Table of contents

Metal-oxide-semiconductor (MOS) structures are essential for a wide range of semiconductor devices. This study reviews the development of MOS Schottky diode, which offers enhanced performance when compared with conventional metal-semiconductor Schottky diode structures because of the presence of the oxide layer. This layer increases Schottky barrier heights and reduced leakage currents. It also compared the MOS and metal-semiconductor structures. Recent advances in the development of MOS Schottky diodes are then discussed, with a focus on aspects such as insulating materials development, doping effects, and manufacturing technologies, along with potential device applications ranging from hydrogen gas sensors to photodetectors. Device structures, including oxide semiconductor thin film-based devices, p-type and n-type oxide semiconductor materials, and the optical and electrical properties of these materials are then discussed with a view toward optoelectronic applications. Finally, potential future development directions are outlined, including the use of thin-film nanostructures and high-k dielectric materials, and the application of graphene as a Schottky barrier material.

The data processing regarding AFM nanoindentation experiments on biological samples relies on the basic contact mechanics models like the Hertz model and the Oliver & Pharr analysis. Despite the fact that the two aforementioned techniques are assumed to provide equivalent results since they are based on the same underlying theory of contact mechanics, significant differences regarding the Young's modulus calculation even on the same tested sample have been presented in the literature. The differences can be even greater than 30% depending on the used model. In addition, when the Oliver & Pharr analysis is used, a systematic greater Young's modulus value is always calculated compared to the Hertzian analysis. In this paper, the two techniques are briefly described and two possible reasons that accurately explain the observed differences in the calculated value of the Young's modulus are presented.

In the present study, a Co-rich CoCrNi-AlTi high-entropy alloy was designed and fabricated by hot forging and 700 °C for 8 h annealing process. The microstructure of the resultant alloy was composed of three multicomponent-phases with the face-centered cubic (FCC) structure, hexagonal close-packed (HCP) structure and L1₂ structure, respectively. The alloy exhibited a remarkable combination of tensile yield strength (gigapascal scale) and plasticity (uniform strain over 30%) at both room and cryogenic temperatures. The cooperative operation of multiple mechanisms consisting of refined-grain strengthening, second-phase strengthening, precipitation strengthening, stacking faults and phase-transformation toughening was suggested to be responsible for the excellent mechanical response.

Chemical vapour deposition (CVD) has emerged as the dominant technique to combine high quality with large scale production of graphene. The key challenge for CVD graphene remains the transfer of the film from the growth substrate to the target substrate while preserving the quality of the material. Avoiding the transfer process of single or multi-layered graphene (SLG-MLG) has recently garnered much more interest. Here we report an original method to obtain a 4-inch wafer fully covered by MLG without any transfer step from the growth substrate. We prove that the MLG is completely released on the oxidized silicon wafer. A hydrogen peroxide solution is used to etch the molybdenum layer, used as a catalyst for the MLG growth via CVD. X-ray photoelectron spectroscopy proves that the layer of Mo is etched away and no residues of Mo are trapped beneath MLG. Terahertz transmission near-field imaging as well as Raman spectroscopy and atomic force microscopy show the homogeneity of the MLG film on the entire wafer after the Mo layer etch. These results mark a significant step forward for numerous applications of SLG-MLG on wafer scale, ranging from micro/nano-fabrication to solar cells technology.

Here, the non-specific interaction of the H1N1 influenza virus with a porous layer of silicon nanowires (PSi NWs) was studied by transmission and scanning electron microscopy (TEM, SEM, respectively) and optical spectroscopy. PSi NW layer with a thickness of about 200 nm was fabricated by metal-assisted chemical etching of p-type highly doped crystalline silicon wafers, and consist of porous nanowires with a diameter of 50–200 nm, and a distance between the nanowires of 100–200 nm. It was shown that during the adsorption of viruses, viral particles with a diameter of about 100 nm bind to the porous surface of the nanowires. This interaction was revealed using TEM, SEM, and causes wavelength shifts in the Fabry–Perot fringes in the reflection spectrum of visible light from the PSi NW layer. The results show that thin layers of PSi NWs are a promising nanomaterial for creating filters and sensors for binding and detection of viruses.

In this work TiO₂, Holmium doped (Ho-TiO₂) Titanium oxide nanoparticles (NPs) and the corresponding nanostructured combinations (Ho-TiO₂/ZnO NC) were successfully synthesized through sol gel method and reflux techniques respectively. The prepared nano materials were characterized with the help of x-ray diffraction Analysis (XRD), UV–visible spectroscopy, Scanning Electron Microscopy (SEM), Energy dispersive x-ray Analysis (EDX) and Fourier Transform infrared spectroscopy (FT-IR). The absorption spectra of nano materials were used for band gaps calculation. The band gap of pure TiO₂ NPs was found to be 3.10 eV which was effectively tuned to 2.65 eV by the doping of Holmium at different concentrations. XRD patterns confirmed the crystalline nature and purity of the synthesized nano materials. Morphology and elemental composition of the material were investigated using SEM and EDX respectively. FTIR helped in detecting the functional groups and grafting of the dye on the surface of nanoparticles. The nano materials were used as Photo-anodes in dye sensitized solar cells (DSSC). Pyrocatechol Violet dye was used as a photo-sensitizer. P3HT (polymer), a hole conducting polymer, was employed as a solid state electrolyte. I–V measurements were used for characterization of fabricated solar cells. Ho-TiO₂/ZnO nanomaterial photosensitized with Pyrocatechol violet dye gave the highest percentage efficiency of 1.51. Other characteristic parameters of the fabricated devices such as short circuit current (Jsc), open circuit voltage (Voc), maximum power point (Mpp) and fill factor were found to be 11.2 mA cm⁻², 0.41 V, 1.55(mW cm⁻²) and 0.33 respectively.

The Plackett—Burman method was used to identify and rank most affective parameters on hydrothermal synthesis and properties of the 13X zeolite powder with gel composition of Al₂O₃:aSiO₂:bNa₂O:cH₂O. The affective parameters of SiO₂/Al₂O₃ ratio, synthesis mixture alkalinity, synthesis temperature, and water content were selected for further study of their impacts and gel composition optimization using the Taguchi method. The synthesized powders were characterized by XRD and SEM analysis. Synthesis temperature and mixture alkalinity were found as the most affecting parameters on the 13X zeolite synthesis at the best gel composition of Al₂O₃:5.4SiO₂: 13Na₂O: 840H₂O. Then 13X zeolite membranes were synthesized on the seeded supports using the optimum gel composition and impacts of synthesis temperature and time and coating layer number on their H₂ and CO₂ permeances and ideal H₂/CO₂ selectivity were studied. The optimum 13X zeolite membrane for H₂/CO₂ separation was obtained by three layer coatings at 80 °C for 16 h with H₂ permeance of 2.88 cm³ cm⁻².Pa.s and ideal H₂/CO₂ selectivity of 4.72.

The interaction of metal oxide nanoparticles (NPs) with cells and lipid bilayers is precarious in various fields such as antibacterial and drug or gene delivery. These require a strong control over NPs–cell interactions, an understanding of how the NPs surface impact their interaction with lipid bilayers and cells. Therefore, to elucidate Titanium dioxide (TiO₂) NPs of size 8–10 nm and 90–100 nm and their interaction with lipid bilayer of Escherichia coli and Staphylococcus aureus, we studied membrane potential, membrane permeability. Results of the traditional method of checking antibacterial activity - minimum inhibitory concentration (MIC) was co-related with change in membrane potential and membrane permeability. TiO₂ NPs 8–10 nm have profound action on depolarization of membrane potential of E. coli cells, while of S. aureus were not affected. TiO₂ NPs 90–100 nm have very less effect on membrane potential and permeability of both organisms. It is observed that there exists a strong co-relation between antibacterial activity of the TiO₂ NPs and change in the membrane potential and membrane permeability. These observations are also supported by membrane leakage test by estimation of protein, deoxyribonucleic acid (DNA) and potassium ion (K⁺) ion content.

Stretchable and compressible strain sensors play an essential role in various fields with uses ranging from automotive components to medical devices. This study reports on the fabrication and characteristics of stretchable strain and pressure sensors constructed using a carbon nanotube and graphene composite. The sensors were used for gait analysis, an important step in the diagnosis and management of movement disorders. The stretchable and compressible strain sensors were used to measure peak knee sagittal angles and forces under the feet when walking. Gait analysis is usually performed within a laboratory. However, in this research we propose a shift to gait assessments conducted via long-term daily monitoring using wearable devices.

Effects of copper ferrites with different prepared methods on the catalytic degradation of lignin with hydrogen peroxide as oxidant is studied. The microstructure, spectral properties and magnetic properties of copper ferrites prepared with five methods were characterized. The results showed that the microcosmic appearance of the catalysts prepared by the five methods was nanoparticles or irregular blocks. All the samples have strong magnetic properties. However the magnetic saturation intensity, residual magnetic intensity and coercivity of copper ferrite prepared by different methods are distinct. The degradation rate and the content of benzene-ring substances were the highest when lignin decomposed under the catalyst of copper ferrite prepared by ethylene glycol assisted sol-gel process, while the content of open-ring substances was the highest when lignin decomposed under the catalyst of copper ferrite made by co-precipitation. Compared with Fenton catalyst, The copper ferrite catalyst easily be separated and good repetitive catalytic performance when used in the lignin degradation. In addition, the crystal structure of copper ferrite play an important role on the catalytic degradation properties of lignin.

We report a fabrication method for the production of nanopillar (NP) or nanohole (NH) arrays together with a micrometer-sized structure within a single layer. On a 200 mm silicon wafer, we produced 200–400 nm NP or NH arrays using electron beam lithography (EBL). The EBL patterns on a positive-tone EB resist—either a poly(methyl methacrylate) or chemically semi-amplified resist—were transferred to a hard mask oxide (HMO) layer using reactive-ion etching (RIE), as the first etching step. We used the HMO as an intermediate layer to connect the EB patterns to photolithography patterns. On the EB-patterned HMO layer, large-scale photolithography patterns were produced on a photoresist (PR), and transferred to the HMO layer using the second RIE step. After removing the PR, the mixed EB and photolithography patterns in the HMO layer were transferred to the target layer in the third RIE step. Our method offers an efficient way to combine nanometer-sized EBL patterns with high-throughput photolithography patterns in a single layer.

This study is based on a simple, low-cost and a novel approach towards the removal of excess fluoride ions from aqueous solution by absorbing fluoride on porous vaterite calcium carbonate nanoparticles (PVCCNPs) synthesised using ethylene glycol-water soft template method. SEM images clearly show the porous nature of aggregated nanoparticles present in the dry powder. Physicochemical properties of synthesised PVCCNP and fluoride on PVCCNP was characterised further by FTIR, XRD, XRF, EDX, and TGA-DTG. Fluoride removal by PVCCNPs from 100.00 ml of 10.0 mg l⁻¹ NaF solution with 0.500 g of PVCCNPs, determined using a fluoride ion-selective electrode, indicates that around 90% removal is achieved within 1 h thus reducing the level to desired 1 ppm. The pseudo-second order kinetic model has a better fit to describe the adsorption of fluoride on PVCCNP than pseudo-first order model. The Langmuir isotherm model is more appropriate to describe the equilibrium behaviour of the adsorption process, than the Freundlich model. Given that the value of n (Freundlich constant) is greater than 1 (3.07) and R_L value is in the range of 0 < R_L <1 (0.014–0.024) implies that the adsorption process is spontaneous and fluoride ions are favourably adsorbed on PVCCNPs. Langmuir model shows that the maximum adsorption capacity of fluoride is 1.956 mg g⁻¹. Excess fluoride in drinking waters causes several severe ill-health effects and filter media based on these nanoparticles can be used to remove fluoride down to safe and required levels to tackle these health problems. As such, PVCCNPs-based filter can be designed to remove fluoride in drinking waters. This may be a way for controlling fluorosis and many other diseases associated with excess fluoride present in drinking waters.

By exploiting cellulose nanofibril's high aspect ratio and nano-order-unit interconnected web-like structure of poplar wood, a new approach was designed. Steam explosion was used for the pretreatment of the poplar, followed by enzymatic hydrolysis assisted sonication for the preparation of nanocellulose. The effects the cellulase dosage, enzymatic hydrolysis time and temperature on the yield of nanocellulose were studied. Under optimal conditions nanocellulose yield was approximately 13.2%. The chemical composition, crystallinity, and morphology of the composites were characterised using FT-IR, x-ray diffraction and TEM. The results demonstrated that the structure was not destroyed during the preparation process, that the crystal form remained cellulose I, and the crystallinity was 61.98%, 9.15% higher than that of poplar cellulose. The width was between 20 and 50 nm, with high aspect ratio and a web-like entangled structure. Therefore, nanocellulose prepared using this method is an ideal toughening material that could be applied in composite materials.

In this paper, we present a convenient hydrothermal method to synthesize hierarchical microspheres consisting of ammonium aluminum carbonate hydroxide (AACH) nanowires with a diameter of about 400 nm and length ∼50 μm on aluminum foils. After calcination at 900 °C, hierarchical γ-Al₂O₃ microspheres with mesoporous structures were obtained successfully, which possess a high specific surface area of 124 m² g⁻¹ and high porosity of 0.71cm³ g⁻¹. The possible formation mechanism was discussed. The as-prepared mesoporous γ-Al₂O₃ hierarchical nanostructures exhibited improved adsorption performance towards Congo red in aqueous solution, 90% CR could be removed rapidly in 20 min, and its saturation adsorption capacity in 80 mg l⁻¹ Congo red can reach to 180 mg g⁻¹, it suggests that the hierarchical γ-Al₂O₃ microspheres with unique microstructure have potential in wastewater treatment.

Quaternary semiconductor Cu₂FeSnS₄ (CFTS) nanoparticle powder have been prepared by a simple chemical technique. The synthesized CFTS nanoparticles have been characterized via powder XRD analysis, Raman spectra, FE-SEM-EDS, UV-Visible absorption spectroscopy, thermal analysis and electrochemical characterization. Powder XRD and Raman spectroscopy confirm the phase and structure of the prepared nanoparticles. The optical absorption studies reveal that the CFTS nanoparticles have a direct optimal band gap in the range from 1.32 to 1.5 eV, which indicates that these nanoparticles are potential absorber materials for thin-film photovoltaic application. The synthesized CFTS nanoparticles were transformed to the ink form and the obtained nanoparticle ink coated on a FTO conducting substrate (surface resistivity-13 Ω sq⁻¹). The catalytic activity of the substrate was analyzed by electrochemical impedance spectroscopy (EIS) and cyclic voltammogram (CV) curves. The appropriate optical band gap and stable electrical properties indicate that Cu₂FeSnS₄ Nanoparticles are potential materials for thin-film photovoltaic application.

Zinc oxide (ZnO) nanowires (NWs) are gaining importance in optoelectronics because of their excellent electrical and optical properties. However, defects in the NW structure leads to suppression of the near-band-edge (NBE) ultraviolet (UV) emission, limiting their full potential for applications in optoelectronic devices. In this work, we present enhancement in NBE emission and bandgap modulation in ZnO NWs hydrothermally grown on sputtered Al-ZnO (AZO) films. Al dopant incorporation and post-synthesis thermal annealing are found to increase the NBE emission. Compared to Al-doping, the post-growth annealing produces a more significant enhancement in the NBE emission and a substantial increase of 34.5 meV in the optical bandgap, along with suppression of defect-related deep level emissions caused by oxygen vacancies and interstitials. This further improves the applicability of the ZnO NWs in stable, room temperature emission devices.

Conversion of carbon dioxide (CO₂) and water (H₂O) to methanol (CH₃OH) is achieved through an artificial photosynthesis procedure utilizing cobalt (Co) micro-particle based photocatalyst and solar energy in a simple, closed reactor. The photocatalyst is fabricated by exposing the surfaces of cobalt microparticles to femtosecond laser irradiation in a gold chloride (AuCl) solution. The morphology and composite of the photocatalyst surfaces were observed and detected to be a layer of cobalt dioxide (CoO) nano-flakes on which some gold (Au) nanoparticles were deposited. The Au nanoparticles harvest the Sunlight energy through a plasmonic effect. The energy absorbed by Au nanoparticles creates electrons and holes which excite the H₂O and CO₂ molecules adsorbed on CoO nanostructure surfaces to form excited hydrogen (H₂)* and excited carbon monoxide (CO)* on the CoO surface. The excited molecules combine to form CH₃OH on the CoO surface. The Au/CoO/Co nanostructured surfaces are useful for developing a low-cost method to convert solar energy to chemical energy in the form of methanol.

Silver nanoparticles are synthesized by employing argon atmospheric pressure DC microplasma technique. Specifically, the variation in fructose molar concentration is investigated for its role in the size of nanoparticles. The 2 mM molar concentration of fructose is optimum for the production of silver nanoparticles in the range '50 ± 10 nm'. Antibacterial and antifungal action demonstrates that silver nanoparticles with small size and larger surface areas are very effective against bacteria and fungus.

Iron molybdate was prepared via simple solution chemistry method and the photocatalytic degradation of a pesticide (endosulfan) was investigated under visible light irradiation. As-prepared (Fe₂(MoO₄)₃) was characterized using scanning electron microscope (SEM), x-ray diffraction (XRD), energy dispersive x-ray spectra (EDX), diffused reflectance spectroscopy (DRS) and Zeta particle sizer techniques. The iron molybdate crystallite size was 36 nm, while grain size was in the range of 160–340 nm. The particles of polymetallic compound were spherical, highly porous and with fluffy texture indicating high surface area. DRS revealed Fe₂(MoO₄)₃ was active under visible region since band gap value calculated was 2.7 eV. Response surface methodology (RSM) was employed for the optimization of photocatalytic activity (PCA) of Fe₂(MoO₄)₃ as a function of catalyst dose, H₂O₂ dose, solution pH and concentration of endosulfan and up to 77% degradation was achieved at optimum conditions, which was monitored by UV/vis spectroscopy. In response to endosulfan degradation, the chemical oxygen demand (COD) and total organic carbon (TOC) were reduced up to 76% and 67%, respectively. Results revealed that iron molybdate is highly efficient photocatalyst for the degradation of endosulfan under solar light irradiation and could possibly be used for the treatment of endosulfan containing wastewater.

Heavy metals are the main factor of water pollution which seriously threaten residents and aquatic life. Here, we demonstrated a mercury ion (Hg²⁺) sensing device based on gold nanoparticles modified silicon nanowire array for highly sensitive, selective and stable detection of mercury ion. Decorated with gold nanoparticles to increase the number of the thiol groups serving as Hg²⁺ sensitive probe and improve performance, the silicon nanowire array based sensor had a large response electric signal in detecting low concentration mercury ion. Importantly, the devices exhibits excellent mercury ion sensing attributes in the range of 1 ng/l-10 μg l⁻¹ with a fairly low detection limit of 0.06 pM. With similar accuracy to ICP-MS, we detected a know sample (1 μg l⁻¹) and unknown sample in less than 1 min. Additionally, the low-cost fabricated process and label free analysis in river water sample make it a potential method in inspecting mercury in water quality.

Nanomaterials based colorimetric detection is an area of vital importance in the field of sensing applications. The nanoparticles are the main component of colorimetric sensor in replacing the natural enzyme based sensor. In this context, zero valent nanoparticles have revolutionized the field of optical sensing especially due to easily shift of electron, facile and low cost of preparation, and ease of surface modification. In this work, zero valent manganese nanoparticles (ZV-Mn NPs) are prepared through a simple and very quick method and modulated with new type of ionic liquid (IL). As-prepared materials were characterized through FE-SEM, HR-TEM, BET, FTIR, and XRD. Subsequently, the peroxidase like catalytic activity of pure and modified ZV-Mn NPs to catalyze oxidation of N,N',N,N'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H₂O₂) investigated. Moreover, the absorbance peak is observed at wavelength 652 nm. The enhanced catalytic activity of ZV-Mn NPs was attributed to the fast transfer of electron mechanism in between substrate and H₂O₂. The coating of IL on ZV-Mn NPs permitted a low limit of detection 0.2 μM with a linear range of 10–280 μM. This work can find wide spread interest in the colorimetric sensing applications. In order to verify the successful demonstration of H₂O₂ sensor, we have applied it in the dairy milk products with satisfactory results.

In this work, AgNPs/PVA/Cellulose was used as a substrate material for surface Raman scattering enhancement. Silver nanoparticles (AgNPs) was synthesized by Lee and Meisel's method with the average particles size of 15.4 nm. Then, this silver colloid was made a homogenous coating on polyvinyl alcohol and cellulose film and structural characteristics of this material were determined using Scanning Electron Microscopy (SEM). The findings demonstrated that the Raman shifts of the pesticide will be identified by the SERS method at 1660 cm⁻¹, 2234 cm⁻¹ (strong intensity), and at 3077 cm⁻¹, 1033 cm⁻¹, 1457 cm⁻¹ (medium intensity) when using the excited laser with wavelength of 532 nm. Under excited laser, the limit of chlorfenapyr detection is 1 ppm (mg l⁻¹), allowing determination of chlorfenapyr residue in food. Potential applications identified food samples containing chlorfenapyr residue for rapid detection, low cost, non-destructive nature and minimal sample preparation.

Two-dimensional (2D) graphene monolayer has been attached importance because of the fantastic physical properties. In this work, we conduct the atomistic simulations to evaluate the phonon behaviors in isotopically doped graphene with Sierpinski Carpet (SC) fractal structure. The thermal conductivities (k) with different fractal numbers are calculated by molecular dynamics simulation. The relationship between the k and the fractal number from 0 to 8 shows a first decreasing and then stable trend. The maximum reduction ratio of the k in SC fractal structures is 52.37%. Afterwards, we utilize the molecular dynamics simulation, phonon wave packet simulation and lattice dynamics simulation to investigate the phonon density of states (PDOS), energy transmission coefficient (ETC), phonon group velocity and participation ratio (PR) in SC fractal structures. In SC fractal structures, the PDOS increases in the low frequency region and the G-band will soften with the enhanced fractal number. We also observe that the isotopic doping atoms can lead to continuous reflected waves in SC fractal structure regions. Moreover, phonon modes in SC fractal structures possess the lower ETCs, phonon group velocities and PRs in comparison with the pristine graphene monolayer. Therefore, we attribute the lower k in SC fractal structures to the stronger phonon-impurity scattering and the increasing localized phonon modes.

Gadolinium aluminate (GdAlO₃, GAP) nano whiskers were synthesized by the hydrothermal-solid state method, Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and thermogravimetry-differential thermal analysis (TG-DTA) were employed to analyze the phase change and the nucleation mechanism of GAP during calcing process. The results show that the precursor of GAP prepared by hydrothermal is (NH₄)_xGdAl(OH)_y(NO₃)_z·nH2O. When the calcination temperature is higher than 900 °C, the precursor recrystallizes, forming the needle shape GAP under the synergistic effect factors. The best preparation conditions are as follows: ammonia water as mineralizer, pH = 9, calcination temperature 1100 °C and holding time 3 h.

Electrospinning has received wide attention for the preparation of uniform diameter nanofibers (ranging from 5 nm to several hundred nanometers) in films with random as well as aligned fashions of the fibers of various materials for use in biomedical applications. Electrospinning research has provided an in-depth understanding of the preparation of light weight, ultrathin, porous, biofunctional curcumin/gelatin nanofibers having applications in wound dressing, drug release, tissue engineering, etc. In the first half of this article, prior research on electrospun curcumin/gelatin nanofibers is reviewed in depth with nanofibers being desired due to their low diameters since these would have then large surface area to volume ratio and enough film porosity as well as improved mechanical (tensile) strength so that when prepared as mats these nanofibers (having high biocompatibility) could be used for sustained release of curcumin and oxygen to wounds during healing. The synthesis of ultrathin nanofibers (having minimum average diameter) is not a simple task unless numerical investigation is carefully done in the first half of this research article. The authors research described here examined the effects of critical process parameters (in the second half of the paper) such as distance between the spinneret and collector, flow rate, voltage and solution viscosity, on the preparation of uniform and ultrathin nanofibers using scanning electron microscopy (SEM) for characterization of the nanofibers. A 2^k factorial design of experiment was found to be a suitable and efficient technique to optimize the critical process parameters used in the preparation of the biofunctional nanofibers with the purpose of having applications in the treatment of problematic wounds such as diabetic chronic ulcers. After parametric investigation, the distance, flow rate and voltage when taken together, were found to have the most significant contributions to the preparation of minimum diameter nanofibers. The primary objective of this research was fulfilled with the development of ultrathin curcumin/gelatin nanofibers having a 181 nm (181 ± 66 nm) average diameter using the optimized setting of a solution having 1.5% gelatin, and 1% curcumin in 10 ml of 98% concentrated formic acid, with the electrospining unit having a voltage of 10 KV, distance from the spinneret to collector drum of 15 cm, flow rate of 0.1 ml h⁻¹, viscosity of 65 cP and drum collector speed of 1000 rpm. However, the lowest average diameter of nanofiber was measured around 147 nm (147 ± 34 nm) which was prepared at a higher voltage, such as 15 KV (at 10 cm distance, 0.15 ml h⁻¹ flow rate and 65 cP viscosity) using the solution. The design of this research paper is based on the view that merely optimization of biofunctional nanofibers may not fully satisfy researchers/engineers unless they are also provided with sufficient information about (a) the entire electrospinning mechanism (numerical investigations of the mechanism) to have better control over preparation of ultrathin nanofibers, and (b) applications of the resulting ultrathin biofunctional nanofibers while fabricating nanofibrous mats (as used now-a-days) for sustained release of curcumin during the critical hours of wound healing and other biomedical applications.

In the present work, the effect of annealing temperature on structural, optical and electrical properties for sol gel synthesized Zn₂SnO₄ nanostructured films has been investigated for their suitability in optoelectronics. These samples were probed by using XRD, UV-Visible spectroscopy, photoluminescence spectroscopy and Hall measurements. The x-ray diffraction study divulges the polycrystalline nature and phase transition from cubic inverse spinal Zn₂SnO₄ phase to pervoskite ZnSnO₃ phase in the synthesized films. The optical transmission of ∼43 %–73 % in the visible region while the optical gap varies from 3.61–3.95 eV has been observed for the annealed films. The defect related emission peaks at 423, 445 and 481 nm has been observed. The lowest electrical resistivity (5.8 × 10^–3 Ω cm) and highest figure of merit  (10^–3 Ω⁻¹) for the films annealed at 600 °C has been observed. These results are very important for the development of new n-type transparent conductor for various optoelectronic devices.

In this study, silica-graphene oxide nano–composites were prepared by sol-gel technique and deposited by spray pyrolysis method on glass substrate. The effect of changing the graphene/silica ratio on the optical properties and wetting of these nano–structures has been investigated. The structural and morphological properties of the thin films have been studied by x-ray diffraction spectroscopy (XRD), field emission scanning electron microscope (FESEM), energy dispersive x-ray spectroscopy (EDS) and atomic force microscope (AFM). XRD results show that silica structures present in the synthesized films exhibit amorphous character and there is a poor arrangement in graphene plates along their accumulation directions. The relationship between the contact angle of the water drop and the surface of thin films was analyzed by surface roughness. The results show that the contact angle is also decreased by decreasing the surface roughness. Absorption and transmittance spectra obtained from (UV–vis) of the studied films were used to compute and determine some optical parameters such as absorption coefficient, transmittance rate, optical gap, refractive index and extinction coefficient of the films. The calculated optical band gaps of films decrease by increase the silica contents in these structures.

The morphology of graphene has an important impact on its applications such as sensing and energy storage. In this study, the evolution of the surface morphology and defect types of graphene that was directly grown on Al₂O₃ by plasma enhanced chemical vapor deposition (PECVD) was investigated by controlled growth conditions. It was found that the defect type of graphene was determined by the ion source power while the surface morphology of graphene was determined by the combination of growth temperature and ion source power. The type of defects of graphene changed from vacancy-like to boundary-like as the ion source power increased, and the morphology of graphene changed from two-dimensional (2D) to three-dimensional (3D) as the temperature rose or the power of the ion source increased. The hydrophobicity of graphene was well correlated with surface morphology, in which the contact angle of graphene changes from 78° to 132° with the change of graphene from 2D to 3D.

SiO₂ aerogels were prepared by sol-gel method and methyl alkylation reaction using TEOS as silicon sources. Silica-supported polyethylenimine (PEI/SiO₂) adsorbents for CO₂ adsorption were prepare by grafting techniques, in which mesoporous SiO₂ aerogel was loaded with PEI and organic compounds functionalized by hydroxyl or amino groups as dopants. CO₂ adsorption isotherms of PEI amine-modified SiO₂ aerogels were measured and the results show that the maximum CO₂ adsorption capacity (1.8 mmol g⁻¹) was obtained over a doped SA-PEI-N-Y loaded with 45% PEI and 15% N-Y (N-[3-(Trimethoxysilyl)propyl]ethylenediamine, denoted as N-Y). In addition, SA-PEI-N-Y has stronger thermal stability than SA-PEI-60% in nitrogen from room temperature to 800 °C at a heating rate of 10 °C min⁻¹. It turns out that N-[3-(Trimethoxysilyl)propyl]ethylenediamine is the best dopant.

The aim of this study is the investigation of the interaction between dyes and polymers which have different polarities. Dye doped polymer films have larger application areas because of the fact that dye is more stable when doped in polymer compared to solvent medium. However, dye dispersion in the polymer medium affects both the spectroscopic and mechanical properties of the polymer. The polymer-dye interaction must be high for a good dispersion,. In this study, polypropylene with apolar character and polymethylmethacrylate with polar groups were chosen as a solid phase to examine polymer-dye interactions. The photophysical properties of phenanthroimidazole-azo compounds synthesized previously were examined with UV–visible and fluorescence spectroscopy techniques in tetrahydrofuran and two polymer media. Also, photostability tests of azo dyes in THF and polymer films were performed. Surface roughness characterizations of polymer films were carried out with AFM. Additionally, the viscoelastic behaviors of the polymethylmethacrylate and polypropylene films under sinusoidal vibrations at different temperatures were studied by dynamic mechanical analysis technique.

We modelled deep indentation in brittle materials via a tensorial approach in three dimensions. Experimentally, we performed deep indentation in base catalyzed aerogels. When deep indentation is performed in these materials, it appears a Hertzian cone crack for both experimental and numerical results. The cone angle (angle between the surface and the boundaries of the Hertzian cone) depends on the material in which indentation is performed. The Young moduli of the materials has no effect on these angles. The tendency is that materials with increasing Poisson ratios have a decreasing value of the Hertzian cone angle.

Aerodynamic levitation method has been successfully used to prepare new Er³⁺/Yb³⁺ co-doped La₂O₃-Nb₂O₅-Ta₂O₅ glasses. 980 nm laser can be used to excite the glass for strong absorption of Yb³⁺ ions. The glass show high infrared transmittance of ∼80%. Moreover, the OH⁻ concentration is very low with the value of ∼7 ppm, indicating excellent infrared transmission. The glass performs good optical properties with refractive index of near 2.3. The plane sweeping of EDS reveals that Er³⁺ and Yb³⁺ are distributed homogeneously in the glass. Strong down-conversion luminescence centered at 1530 nm has been achieved from the glass excited at 980 nm. The near-infrared emission is due to the transition of ⁴I_13/2 → ⁴I_15/2 in Er³⁺ ions. After fitting the decay curve, the lifetime of the near-infrared emission can be decided to be ∼5.517 ms. Such long lifetime is very helpful for rare earth ions to achieve strong emission.

Glass fiber reinforced polymer (GFRP) composites have high sensitivity to UV radiation, temperature, and moisture, and these factors lead to the decrease of mechanical properties. This study attempts to modify unsaturated polyester (UP) and vinylester (VE) resins with nano zinc oxide (ZnO) and organo-montmorillonite (OMMT), in order to improve UV radiation resistance and hygrothermal resistance. The nano ZnO/OMMT modified UP and VE based GFRP composites were subjected to UV radiation and hygrothermal aging at 30 °C, 50 °C and 60 °C (95% RH) for 90 days. Mass loss, moisture uptake, color change, flexural properties and short-beam-shear test were investigated. In comparison to unmodified GFRP specimens, ZnO/OMMT modifying decreased the mass loss, the color change, saturation moisture uptake, and the coefficient of diffusion. After exposure in UV radiation for 90 days, the flexural strength and interlaminar shear strength of nano modified GFRP composites increased by 23.5% and 27.8% compared with those of the unmodified GFRP composites. Nano ZnO/OMMT modifying also increased the flexural strength and interlaminar shear strength by 26.5% and 27.2% in hygrothermal condition at 60 °C. Furthermore, based on the change of mechanical properties and Arrhenius rate model, a prediction model was proposed to predict the life of nano modified FRP composites.

In this study, groundnut shell powder (GSP) was used for the reinforcement of recycled polypropylene (recycled PP). The GSP consisting of two-particle sizes viz (0–250 μm and 250–420 μm) was partly treated with sodium hydroxide at room temperature and the GSP both treated and untreated were compressed and compounded with recycled PP to produce GSP-recycled PP composites. For comparison, recycled PP was equally produced as a control sample. The effects of GSP addition and sodium hydroxide treatment on recycled PP were investigated through the mechanical testing of the developed composites. The mechanical properties (tensile strength, hardness, and toughness) of the composites were evaluated and the tensile strength of both treated and untreated GSP-recycled PP composites is higher than the recycled PP and the treated GSP of particle size 0–250 μm having the highest tensile strength at 25 wt% GSP in recycled PP matrix. The hardness of the recycled PP increases with increasing content of GSP while the toughness decreases with increasing concentration of GSP in the recycled PP matrix. The water uptake of the GSP-recycled PP composites was equally studied, and the results revealed that the treated GSP-recycled PP composites has lower rate of water absorption as compared to untreated GSP-recycled PP composites Thermal stability and crystallinity of the composites and monolithic recycled PP were investigated, and it was discovered that the thermal stability and crystallinity of the polymer were enhanced with GSP addition. Morphological characterization of the selected samples through a scanning electron microscope (SEM) and x-ray diffraction (XRD) were equally done to validate the mechanical performance of the composites. Finally, biodegradability study on the composites and the control sample was conducted and it was found out that, the addition of GSP in both forms promotes the biodegradation of the recycled PP polymer. Such biodegradable GSP-recycled PP polymer composite materials are highly valuable for manufacturing food takeaway packages and some of the interior parts of the automobiles.

This research was based on influence of various fly ash filler content in the machining properties of Pineapple (P)/Sisal (S) hybrid fiber reinforcement composites. Fly ash from bio waste materials of Bagasse (BGFA), Banana (BFA) and Coir (CFA) were used. High hardness nature of 3% BFA (22.73 HV) and 3% CFA (23.85 HV) reduces Material Removal Rate (MRR) and increases its surface roughness nature of the composites. Maximum MRR of 376.38 mm³ min⁻¹ was observed in 3% BGFA combinations with 250 MPa Water jet Pressure (WP), 1mm Standoff Distance (SOD) and 20 mm min⁻¹Traverse Speed (TS) as machining parameters. MRR of 353.64 and 352.76 mm³ min⁻¹ was found out with 1% CFA and 1% BFA combinations. Lower surface roughness of 6.39 μm, 6.71 μm and 6.75 μm was found in 3% BGFA, 1% CFA and 1% BFA based composites. Filler surface created a tight bonding with the matrix, which reduces the erosion of fiber particles at higher WP. Untreated fibers showed lesser machining properties due to low fiber/matrix bonding. SEM results showed reducing of cracks and matrix breakages by the substitution of filler powders.

Graphene has an important positive impact on improving polymer material properties, making the application of composite materials widely available. This paper investigates the influence of graphene on the thermal and mechanical properties of Ethylene-vinyl acetate (EVA) by the molecular dynamics (MD) simulations. The thermostability and mechanical properties of the graphene/EVA nanocomposites are analyzed in terms of the glass transition temperature (T_g), mean-square displacement (MSD), modulus, interfacial binding energy (IBE), stress-strain relationship, yield strength, and tensile strength. The influences of the size of graphene on the thermal stability and mechanical properties of EVA are analyzed and discussed. The simulation result indicated that the glass transition temperature, modulus, yield strength, and ultimate strength of the nanocomposites are higher than that of pristine EVA, which is in good consistent with recent experiments. We attribute this finding to the fact that the strong interfacial bonding of graphene to EVA limits the fluidity of the EVA chains and improves the thermal stability and strength of the graphene/EVA composites. The incorporation of graphene enhanced the thermal stability and mechanical properties of EVA.

Epoxy networks of the diglycidyl ether of bisphenol A (DGEBA) were prepared using 4, 4'-diaminodiphenyl (44'DDS) and 3, 3'-diaminodiphenyl (33'DDS) sulfone diamines crosslinking hardeners. The structural, linear optical and mechanical properties of the investigated sample were analysed. Dynamic Mechanical Thermal Analysis and wide-angle x-ray diffraction were conducted to select a candidate presenting interesting thermo-mechanical properties and particular nanostructures embedded in an amorphous matrix. Our choice is therefore focused on DGEBA/33'DDS polymer for which, rocking curve measurements revealed the existence of two principal reflecting planes inclined to each other by about 0.27°. To highlight the potential effect of these interfaces, Thermally Stimulated Depolarization Current (TSDC) and Time Domain Spectroscopy measurements have been carried out. The application of the windowing polarization TSDC technique, in DGEBA/33'DDS polymer sample, gives an almost linear variation of the activation energies in the range between 3.65 and 4.09 eV. To our knowledge, this is the first study concerning epoxy polymers in which activation energies associated to ρ interfacial charge relaxations are calculated. To study the effect of the interfaces and trapped charge carriers, correlated by the angle x-ray diffraction measurements, the optical parameters were investigated. Our contribution will open a new avenue for developing the DGEBA/33'DDS polymer sustainable candidate in optoelectronic engineering applications.

Based on Abaqus software, the temperature profiles during laser heating CFRP materials in different fiber directions was investigated in this research. The 3D temperature distribution and temperature history of laminates with different ply directions were analyzed and compared through the homogenous model. It is found that the focusing characteristics of laser causes a large temperature gradient. Meanwhile, the temperature field of CFRP laminate extends toward the direction of fibers because of the large axial thermal conductivity of carbon fibers. The thermal conduction in the thickness direction is poor, so the lower layer will not reach the melting temperature. In order to verify the validity of the model, a real-time temperature field measurement device consisting of thermal imager and thermocouples was built. The results show that the model can effectively simulate the temperature field of composite materials irradiated by laser.

The current research work focused on the abrasive wear behavior of the basalt fabric as reinforcement in epoxy and polyester composites. Traditional hand-layup technique is used to manufacture the composites. The mechanical characteristics of the basalt fiber reinforced composites have been reported. The two body abrasive wear behavior of the fabricated composites was conducted by using pin/ball on disc tester TR-20 disc equipment. Test were conducted at two different load of 5 N and 10 N, for various sliding distances of 25 m to 100 m at equal intervals with 400 grade grit of particle size 35 μm. Wear resistance of the composites were determined by calculated the specific wear rate of the composites. Basalt fiber as reinforcement in epoxy composites showed better wear resistance than basalt fiber as reinforcement in polyester composites. Wear mechanism of worn samples is conducted by using the Scanning Electron Microscopy (SEM).

In order to improve the toughness of the wood-polymer composites, the microcellular structure was introduced to the polypropylene (PP) based wood-polymer composites by the technology of continuous extrusion in this article. In order to improve the mechanical and thermal properties of the samples further, the content of both wood flour (WF) and the chemical blowing agent were investigated. Besides, the compound foaming agents were also applied in the process of extrusion. According to the experimental results, the addition of WF contributed to increase both the softening temperatures and the apparent densities of the samples, and the best mechanical properties and microcellular structure were obtained when the mass ratio of WF to PP increased to 3/7. In addition, compared with the granular blowing agent, the powdered foaming agent showed a great advantage in dispersion, which helped to improve the bubble morphology and the mechanical strengths of the samples. Furthermore, the minimum bubble size and the maximum bubble density were both achieved at the powder content of 1 phr.

In the present work the possibility is considered of a chemical sensor synthesis for quantitative glutathione (GSH) determination. Sensor is based on a composite working electrode containing an array of micron-sized Ag particles immobilized on a conductive substrate (Ti) coated by dielectric TiO₂ film. To determine GSH in biological fluids, particularly, in saliva, electrochemical silver-based sensors can be used, since such sensors contain –SH group. With the use of cyclic voltammetry (CV) with a composite working electrode containing an Ag microparticles array, the threshold of quantitative GSH determination is reduced to nM level. Since other modern analogues are inferior at least one order of magnitude in the limit of quantitative GSH detection, we assume that the proposed sensor may be of great interest for clinical diagnosis.

In this study, pure titanium and hydroxyapatite (HA) doped titanium alloys used as Surgical Implant Materials by weight percentage (wt%) of 5% and 10% were sintered by powder metallurgy method. Total 9 samples of these alloys are produced, three of them are pure titanium's, which are sintered at 900, 1000 and 1150 °C temperatures, respectively, for 4 h. From the rest of 6 samples, 3 samples were added 5 wt% HA and the last 3 samples were produced by doped 10 wt% HA. Titanium alloys produced by admixture with HA are sintered for 4 h at 900, 1000, 1150 °C temperatures, respectively. Titanium and HA powders were milled for 2 h in a ball-milling mixer and then pressed for half an hour at 20 MPa pressure. EDX, SEM, XRD and Vickers hardness tests were carried out for the analysis of the samples. As a result of the analysis, it was observed that different sintering temperatures caused to various Vickers hardness values and micro-structural changes occurred for pure titanium and HA doped titanium alloys. In addition, multiple phase and Ti plus HA structures were detected in XRD diffractometers of the samples at these temperatures. Most importantly, for the first time in our study, P₃Ti₅ phase was revealed with 00-045-0888 > XRD card. Finally, the effects of sintering temperatures and HA-doped amounts on particle sizes and pore sizes of the samples were determined by SEM analysis.

The perovskite-type oxides ABO₃ have a multifunctional application in different area such as promising new anode for rechargeable batteries (Ni/MH), photovoltaic and photochromic, because of their properties variety. In this work, we interested on the calculation of the electronic, optical and transport properties of the lanthanum gallate perovskite oxides compound, using the first-principles calculations based on the density functional theory. We determined the exchange and correlation effects by a Generalized Gradient Approximation of Perdew−Burke−Ernzerhof (GGA-PBE). As results the energy gaps of LaGaO₃ compound with GGA-PBE have been found as 3.61 eV, from the transport properties we notice that LaGaO₃ is P-type materials with electrical conductivity varied from 0 (Ω.m.s)⁻¹ at 0 K to 10 × 10²⁰ (Ω.m.s)⁻¹ at 800 K.

Improvement of aluminum alloyed p + back surface fields (p + BSF) which is an essential requirement for achieving high efficiency silicon solar cells has been an important task. One of the ways to have better quality BSFs can be to introduce screen printable aluminum pastes with boron content. Two type of pastes were developed in this work and recipes were provided in detail: screen-printable aluminum paste without boron content (B-free-Al-paste), screen-printable aluminum paste with boron content (Al-B-paste). The ingredients of the pastes were optimized and basically evaluated in terms of alloying and impurity characteristics by measurement of sheet resistances, carrier lifetimes and SIMS analysis. Carrier lifetimes of the wafers processed by Al-B-paste maintained at around 300 μs relatively higher than the wafers processed by B-free-Al-paste. P-type silicon solar cells were fabricated using developed pastes and were compared with those of the cells fabricated by commercial aluminum pastes. Best efficiency of 17.8% was achieved with totally vacuum-less cell production process and Suns-Voc analysis were also carried out for fabricated solar cells.

Solution combustion synthesis of calcium aluminate (CaAl₂O₄) nanocomposite using coffee husk extract and its adsorption capacity for removal of Congo red (CR) and Indigo carmine (IC) are reported. Physiochemical properties of adsorbent were studied by PXRD, SEM, TEM and point of zero charge. Batch adsorption studies were conducted to study the effect of adsorbent dosage, pH, contact time, initial dye concentration and temperature on adsorption efficiency of coffee husk derived calcium aluminate nanocomposite (CHCA). Among the isotherms used, Langmuir model explained best the equilibrium data and the maximum monolayer adsorption capacity was found to be 377 and 135 mg/g for CR and IC, respectively. Mass transfer analysis indicated adsorptive removal of dyes was controlled by both external and internal diffusion. Pseudo-first-order model fitted best with experimental kinetic data and adsorption efficiency increased with an increase in the initial bulk concentration of CR and IC. Thermodynamic analysis indicated that adsorption of CR and IC on CHCA is feasible, spontaneous and exothermic in nature. The magnitude of enthalpy and heat of adsorption suggested that the adsorption is physical in nature. The present study explores the potential of coffee husk extract, an agro-based bio-waste, as a novel and eco-friendly fuel in the synthesis of CHCA and the synthesised nanocomposite as a potential adsorbent for the removal of synthetic dyes.

Photocatalytic degradation of methylene blue by graphene decorated titanium dioxide (TiO₂) powders heated at different temperatures was analyzed. The powders were prepared by mixing TiO₂ with graphene prepared by the modified Hummers method. A thermal treatment was applied to mixed and pure TiO₂ powders with the aim of analyze their structural dependence on temperature, and consistently their photocatalytic degradation effect on methylene blue solutions exposed to UV and visible radiation. Structural characterization of the powders was carried out by x-ray diffraction and Raman spectroscopy. When irradiated with UV, the mixed powders showed as high as 87% photocatalytic degradation, while the pure TiO₂ reached values of 59%. For visible radiation, as it is expected, the pure TiO₂ showed no activity, while the mixture presented degradation of 40%.

In this work, the oxygen reduction reaction in the absence or presence of 2.0 mol l⁻¹ methanol and the hydrogen oxidation reaction are studied on RuFe electrocatalyst synthesized by a microwave thermal heating method in water as reaction medium. The electrocatalysts were morphologically and structurally typified by scanning electron microscopy and by x-ray diffraction, respectively. Three crystalline phases were found: Ru, Fe₂O₃ and Fe(OH)₃·(H₂O)_x (Bernalite). Functional tests were performed by convective (rotating disk electrode) and non-convective (linear sweep voltammetry and cyclic voltammetry) electrochemical techniques in 0.5 mol l⁻¹ H₂SO₄. Both RuFe electrocatalysts show interesting electrochemical activities since they can carry out both the oxygen reduction reaction and the hydrogen oxidation reaction.

2D covalent organic framework-1 (COF-1) membrane is a potential hydrogen storage material. The hydrogen storage capacity of Li-decorated COF-1 has been studied by first-principles calculation. The results show its hydrogen storage capacity has been improved significantly by Li decoration, which is 7.69 wt%. Then ab initio molecular dynamics simulations at 300 K have been carried out and the results show that 12 H₂ molecules are stably absorbed on the double sides of COF-1 unit cell decorated by 6 Li atoms and the hydrogen storage capacity is 5.26 wt%.

Li–S battery has high theoretical specific capacity and specific energy, but the shuttle effect challenges its commercial application. So many composite materials had been prepared to conquer it. In this research, MCNT/MoS₂/S composite and MCNT/MoS₂/S composite cathode were prepared respectively by a facile hydrothermal method and by melt diffusion method. MoS₂ and MCNT showed uniformly combined together by SEM and TEM. The electrochemical properties of the MCNT/MoS₂/S cathode were carried out on a Gamry electrochemical workstation. The initial capacity arrive 820 mAh·g⁻¹ at 0.1 C, and specific capacities up to ∼460 mAh·g⁻¹ over more than 300 cycles at 0.5 C. The improvement of electrochemical performance due to MoS₂ strongly adsorbing polysulfide and the conductivity network of MCNT.

This study proposes MnO₂ thin nanosheets assembled microspheres with oxygen vacancies and pre-insertion of Na ions (NaMnO_2−x) as highly capable supercapacitor electrodes. The NaMnO_2−x electrode can reach a stable potential window of 1.2 V without oxygen evolution reactions in three-electrode configuration. The voltage window of the assembled aqueous ASC device can be expanded to 2.4 V (1 M Na₂SO₄) by using NaMnO_2−x electrode and activated carbon electrode as positive and negative electrodes, respectively. The NaMnO_2−x electrode delivers a good specific capacitance of 215 F · g⁻¹ at current density of 1 A · g⁻¹. It displays high-rate capability and an excellent cycling stability, maintaining 95.5% of its initial specific capacitance at 2 A · g⁻¹ after 2500 cycles. The ASC device shows a high energy density and power density of 28.56 W · h · kg⁻¹ and 1246 W · kg⁻¹, respectively, at a current density of 1 A · g⁻¹.

Lubricating grease has increased thermorheological properties during heating, which may affect the lubrication of the friction pair. And a friction pair usually heats up in the working process. This study explored the effect of surface temperature of the friction pair on the lubrication performance under lubrication conditions. The thermorheological properties of lubricating grease were analyzed using a rotational rheometer, and the variations and mechanisms of the thermo- rheological properties were explored. The friction-wear test on lubrication was conducted at different temperatures to examine the effects of thermorheological properties on the tribological behaviors of lubricating grease. Wear scar morphology, composition change, and friction-lubrication mechanisms at different temperatures were probed through SEM and X-ray spectrometer analysis. The results showed that lubricating grease has significant thermorheological properties. Moreover, its soap fiber entanglement decreases with rising temperature, and the entanglement properties are slowly lost at high temperature. The soap fiber structure of lubricating grease plays a vital role in lubrication. As temperature rises, the soap fiber entanglement of lubricating grease decreases and the base oil is more easily released under shear, exhibiting a trend of friction coefficient decreasing with the rising temperature. High temperatures weaken the soap fiber entanglement of lubricating grease, the film-forming property, and the surface friction-abrasion resistance of the friction pair and even cause oxidative wear.

Aiming at dense sintering of silicon carbide ceramic, magnesium alloy powder was taken as additive, and silicon carbide powders with two different particle size were sintered by the same hot pressure sintering process. Result shows that ceramic sintered by the powder with larger particle size is denser. Magnesium and carbon segregation is observed in the sample prepared by powder with smaller particle size, in which silicon carbide particles cannot be uniformly dispersed by sintering additives. However, sintering additives distribute homogeneously among silicon carbide particles in the sample prepared by powder with larger particle size, which can effectively play a bonding role. In the selection of liquid phase sintering additives, particle size matching of raw material and sintering additives should be emphasized.

This study investigates the effect of sulfur on Q235 steel and 16Mn steel corrosion in sodium aluminate solution. The corrosion rate of Q235 steel and 16Mn steel reaches the maximum respectively when S²⁻ and S₂O₃²⁻ form synergistic corrosion and S²⁻ is contained alone. But, the size of corroded particles is smaller in the solution containing only S₂O₃²⁻ for two kinds of steel. The corrosion rate of 16Mn steel is greater than Q235 steel. Surface corrosion of two kinds of steel is both composed of sulfides (FeS and FeS₂) and oxides (Fe₂O₃, Fe₃O₄, Al₂O₃ and NaFeO₂). The crystal particles of steel surface are mainly iron oxides according to EDS analysis. Nyquist plots of Q235 steel with different forms of sulfur have two capacitance-resistance arcs and no diffusion impedance. Nyquist plots of 16Mn steel with S₂O₃²⁻ alone is consistent with Q235 steel. But, Nyquist plots of 16Mn steel presents a typical Warburg diffusion phenomenon with containing S²⁻ alone and forming synergistic corrosion.

There is significant interest in hybrid organic-inorganic (HOI) compounds since these materials offer multiple functionalities and properties that can be tailored at the mesoscopic and nanoscale levels. HOIs investigated for photovoltaic applications typically contain lead or mercury. There is considerably less work done on Zn-based HOIs. These could potentially be considered in biomedical applications due to presence of organic components and the biocompatibility of Zn cations. Using a systematic materials selection approach, we have carried out a detailed search of Zn-HOI compounds in two comprehensive experimental crystallographic repositories: Inorganic Crystal Structure Database and American Mineralogist Crystal Structure Database. Thirteen Zn-HOI compounds are discovered: CuZnO₂(CO₃), Zn(C₂O₄), ((CH₃)₂NH₂)Zn₃(PO₄)(HPO₄)₂, (CH₃NH₃)Zn₄(PO₄)₃, Zn(N(CH₂PO₃H)₃)(H₂O)₃, (CH₃NH₃)Zn(HCO₂)₃, Zn₄(CO₃)₂, Zn₈(HPO₄)₁₆(C₂H₈N)₈, Zn₅(CO₃)₂, (Mg₂Zn)₈(CO₃)₂(OH), Zn₇(CO₃)₂(OH)₁₀, Ca₃Zn₂(PO₄)CO₃(OH).2H₂O, and Zn(CO₃). We have then performed first principles calculations via density functional theory with hybrid functional treatment to determine the electronic band gap and optical response of these materials. Our computations show that eleven of the thirteen compounds have insulating properties with band gaps ranging from 2.8 eV to 6.9 eV. Ten of these are found to have a high absorbance in the far ultra-violet (FUV) region of 200–112 nm wavelength. For example, the absorption coefficient of (CH₃NH₃)Zn(HCO₂)₃ is ∼0.75 × 10⁵ cm⁻¹ for F₂ excimer laser energy (wavelength ∼157 nm) which is more than three orders higher than the average tissue absorbance (∼10^1.5 cm⁻¹) and the refractive index of 1.85 is larger than typical biological matter which is in the range 1.36–1.49. These results suggest that Zn-HOIs could potentially find applications in photothermolysis and UV protection.

The linear generalized Green–Naghdi thermoelasticity theory without energy dissipation is employed. The study of thermoelastic interactions in a hollow cylinder under a continuous heat source is carried out. Firstly, Laplace and Hankel transforms are employed to solve the problem without the time domain. Then, the state space approach is employed to get the exact solution of the problem in the space domain. Once again, the inverse Laplace transforms is used to get the solutions in the time domain. Accurate terminologies for the temperature, thermoelastic potential, axial displacement, dilatation, and stresses are derived. Numerical outcomes for field variables are presented with the view of illustrating the theoretical results.

Silicones which possess, amongst others, remarkable mechanical properties, thermal stability over a wide range of temperatures and processability, and rare earth oxides (REO), known for their unique optic, magnetic and catalytic properties can be coupled into multifunctional composite materials (S-REOs). In addition, the intrinsic hydrophobicity of REO and polysiloxanes makes them easily compatible without the need for surface treatments of the former. Thus, europium oxide (Eu₂O₃), gadolinium oxide (Gd₂O₃) and dysprosium oxide (Dy₂O₃) in amounts of 20 pph are incorporated as fillers into silicone matrices, followed by processing mixture as thin films and crosslinking at room temperature. The analysis of the obtained films reveals the changes induced by these fillers in the thermal, mechanical, dielectric and optical properties, as well as the hydrophobicity of the silicones. The luminescence properties of S-REO composites were investigated by fluorescence spectra and lifetime - resolved measurements with a multiemission peaks from blue to greenish register. The thermogravimetrical analysis indicates an increasing of thermal stability of the composites that contain REO, compared to pure silicone. As expected, the dielectric permittivity significantly increased due to nature of the fillers, while the dielectric loss values are relatively low for all samples, indicating a minimal conversion of electrical energy in the form of heat within bulk composites. The presence of rare earth oxides into the silicone matrix facilitates the motions of long-range charge carriers through the network resulting in higher values of conductivity of the composite films. The stress-strain measurements revealed the reinforcing effect of the rare earth metal oxides on a silicone matrix, leading to a significant increase of Young modulus. The known hydrophobicity of silicones is further enhanced by the presence of REO.

In this article, investigated Ni-based Ni₂CuCrFeAl_x (0.5 ≤ x ≤ 2.5) alloys were prepared by powder metallurgy route. On varying x, the alloy changes from single FCC to single BCC with a transition duplex in FCC/BCC region. The severe scattering effect of lattice in these high-entropy alloys was observed by weak x-ray diffraction intensities. Also, owing to this lattice effect, the observed electrical and thermal conductivity are much smaller than those of pure metal components. On a contrary, because of additional scattering effect of FCC/BCC phase boundaries in the alloys, both conductivity values are even higher than those in the duplex phase region. Present work explains the properties of temperature dependant High-Entropy alloys (HEA's) as a potential new class of thermoelectric materials. The thermoelectric properties can be controlled significantly by changing the valence electron concentration via appropriate substitutional elements. Both the electrical and thermal properties were found to decrease with a lower VEC number. These findings highlight the possibility to exploit HEA's as a new class of futuristic high temperature TE materials.

Polymers and polymeric composites are widely used for various applications due to their outstanding and wide range of properties. Polyurethanes, existing in different types, are novel and versatile polymers with excellent mechanical properties. Thermosetting polyurethane resins are among the most widely used polyurethanes wherein their manufacturing and developing have been introduced during the last few years. Self-healing materials have been inspired by biological systems in which damages provoke healing responses. It is almost cost-effective to use self-healing materials in commercial applications. This study investigates a novel self-activated approach in thermosetting polyurethane resins. A tungsten (VI) chloride (${{\rm{WCl}}}_{6}$) catalyst, a co-activator (phenylacetylene) and a dissolution agent (nonylphenol) were used for the onset of ring-opening metathesis polymerization of dicyclopentadiene. Here different percentages of a catalyst in polyurethane resins were used, the impacts of which on fracture toughness and healing efficiency were also studied. To examine healing efficiency, samples with tapered double-cantilever beam geometry were prepared and using the self-activated method, the development of thermosetting polyurethane self-healing was investigated. The results showed that the concentration of catalyst affects the basic properties of the material and healing efficiency of the composite. The highest healing efficiency of 97% was obtained for a 3 wt% catalyst.

Microwave absorbers have been attracted much more attentions in both military and civil fields nowadays. In this paper, we present a multi-band metamaterial absorber with the excellent performances of wide-angle incidence and polarization insensitivity. The designed absorber is composed of two distinct metallic layers separated by a dielectric substrate. The simulated absorptions of the absorber are 92.9%, 92.5% and 98.5% at 5.92 GHz, 6.12 GHz and 8.54 GHz, respectively. The microwave experiments are performed to verify the simulations, and the measured results are in agreement with the simulations. Surface current distribution is illustrated to investigate the physics of absorption. We believe that the designed absorber has numerous potential applications in stealth, sensing, electromagnetic absorption and thermal detectors.

This paper designs a planar electromagnetically induced transparency (EIT) metamaterial, which comprises an asymmetric ellipse split resonance ring (AESRR) and cut wire (CW). The proposed EIT metamaterial works in the wide range of incident angles and has polarization-sensitive at two transmission dips. The frequency of transparency peak is 10.67 GHz and maintains a high quality-factor (180.84). By calculating the multipole's radiated power, it can be found that the toroidal dipole response is enhanced, while the electric dipole response is suppressed at the transparency peak. Interestingly, this paper firstly uses the radiated power of electric dipole to elucidate the polarization sensitivity in two minimal transmissions. Meanwhile, the coupling mechanism of the EIT metamaterial is analyzed by the two-oscillator model and equivalent circuit.

Epitaxial AlGaSb double-layer structures grown on GaSb (001) substrates by Liquid Phase Epitaxy (LPE) were analyzed by high-resolution x-ray diffraction (HRXRD). Four AlGaSb double-layer structures grown at 450 °C were analyzed varying the thickness of the first layer and maintaining the same thickness for a second layer growth. Symmetric reciprocal space mapping measurements around the (004) reflection and asymmetric rocking curves around the (115) reflections have revealed that a subsequent Al0.15Ga0.985Sb growth on an Al0.047Ga0.953Sb layer modifies the relaxation and lattice tilting of the first layer. This behavior is attributed to the formation of dislocations within the layers during the growth and transported between them. In this work, the study was realized ex situ and is in well agreement with in situ studies and theoretical predictions on the relaxation of epitaxial films in diverse materials. The structural analysis of lattice distortion in epitaxial layers is relevant since it could modify the electrical behavior of optoelectronic devices building with them.

Compressively strained Ge_1-xSn_x films (x = 0.04, 0.08, 0.14) have been grown on Ge(004) substrates by Molecular Beam Epitaxy. The wavelength dependence of the refractive index is deduced as ${\rm{n}}({\rm{x}},\lambda )={{\rm{n}}}_{{\rm{Ge}}}(\lambda )+( \mbox{-} 2+3.5\lambda )x+5(1 \mbox{-} \lambda ){x}^{2}$ in the near-infrared range (NIR) (800–1700 nm) for Ge_1-xSn_x alloy films. That is similar to Si_1-xGe_x alloy films. The Hall measurement shows that the donor levels decrease due to dislocation at room temperature. Temperature dependence of the electron mobility for Ge_1-xSn_x films reveals that strain-induced defects lower the carrier mobility from 10 K to 310 K. The maximum carrier mobility reaches 2082 cm²/V·s at T = 122 K for Ge_0.96Sn_0.04/Ge film. These results indicate that Sn-doping has great influences on electronic properties for Ge_1-xSn_x alloys. Our investigations may be helpful for fabricating the high performance optoelectronic devices.

The finding of a material with the precise properties needed to solve a specific issue is the first topic that needs unraveling when an application is projected. One approach to find a material with a specific property value is to study a different but linked property. The aim of this research is to find materials with similar Electronic Band Structures (EBS); which in a simulation typically contain more than 1,000 ordered pairs of data. Our approach is, instead of calculating the similarities between the EBS of different materials, to calculate the similarity between their crystalline structures, and then the similarity between the EBS of the resulting similar compounds is tested. The software system developed in this research finds materials with similar crystallography, then the similarity of the compounds is tested by comparing the DFT modeled Electronic Band Diagrams (EBDs). The crystallographic data was mined from the Crystallography Open Database (COD) in the form of CIF files; that were used to calculate the x-ray diffraction (XRD) data using REFLEX, a component of Materials Studio. The plane presence, position and intensity of the peaks from the XRD data, were used to calculate the similarity between materials. With the list of similar materials from the previous process and the correspondent CIF files, the CASTEP code (from Materials Studio) was used to calculate the EBDs. In this work, three different materials were analyzed: CdTe, CdSe and GaAs. As results, 2D maps showing 50 compounds with the highest similarities are shown and for the EBD analysis, the 6 + most similar compounds were computed and analyzed by means of the first derivative. It is shown that the EBDs of the similar materials share the same shape, but with different values, making the system a useful tool for Materials Integration.

The spatially continuous control of the physical properties in semiconductor materials is an important strategy in increasing electron-capturing or light-harvesting efficiencies, which is highly desirable for the application of optoelectronic devices including photodetectors, solar cells and biosensors. Unlike the multi-layer growth of chemical composition modulation, local strain offers a convenient way to continuously tune the physical properties of a single semiconductor layer, and open up new possibility for band engineering within the 2D plane. Here, we demonstrate that the gradient refractive index and bandgap can be generated in atomically thin transition metal dichalcogenide flakes due to the effect of thermal strain difference. A highly resolved confocal scanning optical microscopy is used to perform a real-space light-reflection mapping of suspended atomically thin WSe₂ flakes at the low temperature of 4.2 K, in which the parabolic light-reflection profiles have been observed on suspended monolayer and bilayer WSe₂ flakes. This finding is corroborated by our theoretical model which includes the effect of strain on both the refractive index and bandgap of nanostructures. The inhomogeneous local strain observed here will allow new device functionalities to be integrated within 2D layered materials, such as in-plane photodetectors and photovoltaic devices.

Tungsten oxide based gas sensors have attracted a lot of attention in breath acetone analysis due to their potential in clinical diagnosis of diabetes. The major problem with this material in sensor application has been remarkable response to all gases but low selectivity to specific gases. Herein, we report the gas sensing performance of WO₃ materials which were synthesized by varying water and ethanol ratios using a facile solvothermal method for acetone detection. The gas sensing properties of as-prepared WO₃ were tested on acetone C₇H₈, NO₂, NH₃, H₂S and CH₄ under relative humidity. X-ray diffraction patterns show that as-prepared WO₃ samples are mainly composed of monoclinic WO₃, a phase having relatively high selectivity to acetone. The as-prepared WO₃ sensors produced using 51:49 ratio of water: ethanol show an increase in acetone response as the acetone concentration increases and a decrease in acetone response as the relative humidity increases. The sensor responded to a very low acetone concentration ranging from 0.5 to 4.5 ppm which is normally found in human breath. Furthermore, the sensor exhibited high sensitivity and selectivity to low ppm of acetone at 100 °C. On contrary, the sensor showed significantly lower response to other gases tested.

Herein, we first explore an efficient solvothermal method to fabricate hierarchical square biscuit-like BiOBr architecture (SBBA), and further utilize it as a visible-light-responsive photocatalyst. The photocatalytic performance of the resultant SBBA is comprehensively evaluated by photocatalytic degradation of methyl orange solution as a model wastewater under the visible light irradiation. The SBBA photocatalyst with a band gap of ∼2.56 eV exhibits remarkable photocatalytic activities in terms of degradation efficiency and reproducibility. More importantly, a plausible electron transfer and involved degradation mechanism are put forward. The excellent photocatalytic activities consolidate it as a promising photocatalyst in practical wastewater treatment.

This study proposes the High-κ dielectric Trench Shielded power UMOSFET (HK TS-UMOSFET) to be assessed using the two-dimensional numerical simulations. The simulations are employed to evaluate HK TS-UMOSFETs susceptibility to single-event burnout (SEB) mechanism. Based on the findings, the influence of alternative high permittivity gate dielectrics to silicon dioxide (SiO₂) in TS-UMOSFET was discussed. Furthermore, in order to improve the performance of the device, its electrical behaviour was simulated with several high-κ dielectrics including Al₂O₃, Si₃N₄ and Aluminium Nitride (AlN). When heavy ions strike the sensitive areas of the device, the electric field distribution and SEB threshold values were extracted. Based on the values yielded, (AlN) was identified as a promising high-κ material to achieve SEB-hardened TS-UMOSFET compared to the other high-κ dielectrics. In conclusion, with (AlN), the HK TS-UMOSFET offers a high SEB tolerance and improved electrical characteristics.

We investigated the temperature dependence of resistivity in thin crystals of FeSe_1−xTe_x (x = 1.0, 0.95, and 0.9), though bulk crystals with 1.0 ≧ × ≧ 0.9 are known to be non-superconducting. With decreasing thickness of the crystals, the resistivity of x = 0.95 and 0.9 decreases and reaches zero at a low temperature, which indicates a clear superconducting transition. The anomaly of resistivity related to the structural and magnetic transitions completely disappears in 55- to 155-nm-thick crystals of x = 0.9, resulting in metallic behavior in the normal state. Microbeam x-ray diffraction measurements were performed on bulk single crystals and thin crystals of FeSe_1−xTe_x. A significant difference of the lattice constant, c, was observed in FeSe_1−xTe_x, which varied with differing Te content (x), and even in crystals with the same x, which was mainly caused by inhomogeneity of the Se/Te distribution. It has been found that the characteristic temperatures causing the structural and magnetic transition (T_t), the superconducting transition (T_c), and the zero resistivity (T_c^zero) are closely related to the value of c in thin crystals of FeSe_1−xTe_x.

We report the synthesis of Y-substituted Mg–Zn [Mg_0.5Zn_0.5Y_xFe_2−xO₄ (0 ≤ x ≤ 0.05)] ferrites using conventional standard ceramic technique. The samples were characterized by x-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FESEM), FTIR spectroscopy, UV–Vis spectroscopy and quantum design physical properties measurement system (PPMS). XRD patterns confirm the single phase cubic spinel structure up to x = 0.03 and appearance of a secondary phase of YFeO₃ for higher Y contents. FESEM images depict the distribution of grains and EDS spectra confirmed the absence of any unwanted element. Completion of solid state reaction and formation of spinel structure has been revealed from FTIR spectra. The FTIR data along with lattice constant, bulk density and porosity were further used to calculate the stiffness constant (C_ij), elastic constant and Debye temperatures. Mechanical stability of all studied compositions is confirmed from C_ij using Born stability conditions. Brittleness and isotropic nature are also confirmed using Poisson's ratio and anisotropy constants, respectively. The enhancement of dc electrical resistivity (10⁵Ω cm to 10⁶Ω cm) with Y content is observed. The energy band gap (increased with Y contents) is found in good agreement with dc electrical resistivity. Ferrimagnetic to paramagnetic phase change has been observed from the field dependent high temperature magnetization curves. The magnetic moments and saturation magnetization were found to be decreased with increasing temperature. The Curie temperature (T_c) has been measured from temperature dependent magnetic moment (M-T) and initial permeability (μ'_i-T) measurements and found to be in good agreement with each other. Decrease in T_c with Y content is due to redistribution of cations and weakening of the exchange coupling constant. The magnetic phase transition has been analyzed by Arrott plot and found to have second order phase transition. The dc resistivity endorses the prepared ferrites are suitable for high frequency and high temperature magnetic device applications as well.

We investigated the influence of 10% substitution of rare-earth (RE) elements on the crystallographic, transport, and magnetic properties of La_0.67–xRE_xCa_0.33MnO₃(RE = Nd, Sm, and Gd, x = 0.0, 0.1) manganite perovskite compounds. The bulk polycrystalline samples were synthesized using solid-state reaction method. The phase purity and crystal structure of studied samples were confirmed by room temperature X-ray diffraction followed by the Rietveld refinement analysis. A high temperature insulator to low temperature metal phase transition is observed in electrical transport measurement. We observed an enhancement in the temperature coefficient of resistance (TCR) and magnetoresistance (MR) by partially substituting La with RE ions. The maximum TCR ≈ 22% and MR ≈ 96% are observed in Gd doped sample. The magnetic transition temperature, T_c, decreases from ∼254 K for the pristine sample to about ∼165 K for the Gd-doped sample. Our analysis of electrical and thermal transport data shows that the Small Polaron Hopping (SPH) is predominant at high temperatures conduction mechanism, whereas at low temperatures mechanism is dominated by electron-magnon scattering. The high temperature insulator paramagnetic phase to low temperature metallic ferromagnetic phase transitions are also observed in thermal conductivity and specific heat.

We present the studies of structural, magnetotransport, and magnetic properties of Ge_1−xEu_xTe bulk crystals with the chemical composition, x, changing from 0.008 to 0.025. For the samples with x > 0.015 the sample synthesis leads to formation of Ge_1−xEu_xTe spinodal decompositions with a broad range of chemical contents. The presence of Ge_1−xEu_xTe spinodal decompositions is responsible for the antiferromagnetic order in our samples with x > 0.015. For the samples with x < 0.015 the structural characterization shows no evidence for clusters, the samples are paramagnetic, but the analysis of the results of magnetic measurements indicates deviations from the random distribution of Eu ions.

A series of Eu³⁺ and Tb³⁺ co-doped CaMoO₄/SrMoO₄ luminescent thin films were prepared by a facile solution method, and they were annealed at 550 °C for 2 h. The luminescent properties of the thin films were studied, which involve the energy transfer from Tb³⁺ to Eu³⁺. The emission color can be changed from green to red, with increasing Eu³⁺ doping concentration in Tb³⁺-doped CaMoO₄/SrMoO₄ thin films. In addition, it was observed that the PL intensity of Eu³⁺ will enhance when Tb³⁺ ions are incorporated into Eu³⁺-doped CaMoO₄/SrMoO₄ thin films. The optical band gaps of the luminescent thin films are found to be in the range of 4.49 to 4.72 eV. These results revealed that Eu³⁺ and Tb³⁺ co-doped CaMoO₄/SrMoO₄ luminescent thin films have a significantly potential application in electroluminescent devices.

In this work, we used the guided-mode expansion method to calculate the photonic band dispersion in two-dimensional photonic crystal slabs. The photonic lattice is hexagonal, composed of air holes with a circular cross-section. The slab is made of a semiconductor material (GaAs) with a dielectric function dependent on pressure and temperature. By maintaining the constant temperature, we found a shift in the photonic band dispersion towards regions of larger frequencies when the hydrostatic pressure increased. Moreover, we consider the effects of pressure on defective modes in cavities L1 and L3. The results reveal that by increasing the pressure, the position of the defective modes manages to tune for the photonic gap. Additionally, we found a decrease in the Q-factor for the L1 cavity when the pressure increases. However, for the L3 cavity, the Q-factor exhibits a non-monotonous behavior by increasing the pressure.

Development of nanoparticles with multi-functionalities is of great importance. In this study, praseodymium sulfide (Pr₂S₃) and molybdenum sulfide (MoS₂) nanoparticles were synthesized. The structural, morphological and optical properties of the as-obtained products were investigated by XRD, XPS, TEM, UV–vis-NIR spectroscopy, and photoluminescence spectroscopy. Pr₂S₃ is found to be used in selective photodegradation of fluorescein sodium salt. MoS₂ can be utilized for selective photodegradation of rhodamine B. In the mixture of rhodamine B, fluorescein sodium salt and rhodamine 6 G, most of rhodamine B and part of fluorescein sodium salt are optically degraded by Pr₂S₃. In the mixture of rhodamine B, fluorescein sodium salt and rhodamine 6 G, part of fluorescein sodium salt and most of rhodamine B is degraded by MoS₂. Moreover, they emit near-infrared fluorescence (800–1100 nm) when excited by the 785 nm light. Deep tissues imaging with high-contrast is shown, utilizing a nanoparticle-filled centrifuge tube covered with animal tissues (pig Bacon meat). Maximum imaging depth below the tissue surface of 1 cm is achieved. Our work provides a rapid yet efficient procedure to make nanoparticles for dual-application-potential in dye-photodegradation and near-infrared deep tissue imaging.

In the present work, lead zirconate titanate PbZr_0.52Ti_0.48O₃ (PZT) bulk ceramic powders having composition aimed for morphotropic phase boundary (MPB) were synthesized by conventional solid-state reaction and sintered by novel spark plasma sintering (SPS) method. The samples sintered at four different temperatures of 800, 850, 900 and 950 °C are found to have almost same density. The effect of SPS temperature on microstructure, phase constituents and dielectric properties is investigated. Rietveld refinement of XRD patterns of samples was carried out to estimate the phase composition revealing that the enhanced dielectric response is due to the presence of monoclinic phase along with the tetragonal phase in the synthesized material. The maximum room temperature dielectric constant ε_r ∼950 was found for the sample sintered at 900 °C. It is observed that the temperature has a significant role in resulting change of phase composition and dielectric performance of all the samples due to sublimation of PbO content.

The properties of Physical Vacuum Deposit (PVD) films could be improved by doping rare earth elements and other metal elements. In this paper, La-Ti/WS₂ composite films were prepared by unbalanced magnetron sputtering. The effect of target power on the structure and properties of La-Ti/WS₂ composite films was studied. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to analyze the micro morphology, composition and crystal structure of the film. The hardness and friction and wear properties of the film were tested by nano-indentation and friction and wear testing machine. The results show that the structure and composition of La-Ti/WS₂ composite films prepared by magnetron sputtering are affected by the target power. With the increase of the target power, the diffraction peak of WS₂ (002) was shifted to the low θ value, the crystal surface spacing was decreased, the crystal lattice shrinked, the porous structure of La-Ti/WS₂ composite films was decreased significantly, the coarse columnar crystal was refined significantly, and the film density was improved effectively. When the target power is 20 W, the sliding surface of La-Ti/WS₂ composite film (002) is parallel to the surface, showing lower friction coefficient and better wear resistance; when the target power is 50 W, La-Ti/WS₂ composite film has higher hardness, higher wear rate and poor wear resistance. The density and friction and wear properties of La-Ti/WS₂ composite films can be improved by suitable La-Ti content.

Zr-Co-RE non-evaporable getter films have excellent gas adsorption performance therefore can be used in vacuum sealed electronic devices. The microstructure of getter films has vital effect on adsorption performance. In this paper, Zr-Co-RE films deposited by DC magnetron sputtering at different glancing angles are investigated including microstructures and adsorption characteristics. The surface and cross-sectional morphologies demonstrate loose, porous and columnar-like structure which forms because of low lateral mobility of Zr and Co atoms and shadowing effect of non-perpendicular sputtering. Zr-Co-RE films are amorphous or nanocrystalline structure. The films deposited at 90° glancing angle show large grain size. After Zr-Co-RE films are heated at 350 °C for 15 min, the H₂ adsorption capacity and pumping speed at ambient temperature are tested. The films grown at 90° glancing angle have highest initial pumping speed (103.9 ml s⁻¹ cm⁻²), which owe to its more gas diffusion path and active surface, meanwhile, the adsorption capacity is lower than 60° because of difficult and limited diffusion process into getter matrix. The films grown at 60° glancing angle have best adsorption capacity (71.5 Pa.ml cm⁻²) and pumping speed stability.

A comparative study of Mo/B₄C and Mo_xC_1-x/B₄C multilayers deposited by DC magnetron sputtering technology was presented in this paper. Using a homemade real-time stress measure instrument, the stress of two kinds of multilayers was investigated. Characterizations of the multilayers before and after annealing were performed by grazing incident and at-wavelength near-normal incident x-ray reflectivity. Experimental results show that after replacing Mo by Mo_xC_1-x, Mo_xC_1-x/B₄C multilayers obtain relatively smaller compressive stress compared with Mo/B₄C multilayers. The corresponding stress value changes from −0.99 GPa to −0.36 Gpa. Mo_xC_1-x/B₄C multilayers have also proven to have better thermal stability up to 600 °C. After repeatedly annealing from 100 °C to 600 °C, Mo/B₄C multilayers had a ∼2% decrease in near-normal incident reflectivity, while Mo_xC_1-x/B₄C multilayers had a smaller 1.4% loss of reflectivity and a higher stability temperature.

SiO₂ was used as the current blocking layer (CBL) during fabricating the InGaN/GaN-based light-emitting diodes (LEDs). The SiO₂ film was prepared by plasma enhanced chemical vapor deposition (PECVD) at a lower temperature (LT) of 180 °C and a higher temperature (HT) of 280 °C for characterizing the reliability of LEDs. The degradation of output power in LT-CBL LED is as high as 6.8% during 1000 h in the high-temperature and humidity (85 °C/85 RH) condition. Experimental results demonstrate the low temperature grown CBL forms a larger side-wall angle via wet etching. The thinner side-wall ITO film cracks and the current spreading effect is suppressed, causing drastic power degradation. On the contrary, the HT-CBL SiO₂ demonstrates optimal step coverage of ITO film for current spreading and then the HT-CBL LEDs slightly degrade as low as 5% in the accelerated reliability test. A dense quality of HT-CBL SiO₂ as well as a good CBL decreased parasitic optical absorption in the p-pad electrode and p-finger. Besides, the HT-CBL SiO₂ showed a small side-wall angle of 40˚ which increased the step coverage and current spreading of ITO. An approach is conducted to confirm the side-wall profile of CBL for each process.

Present work demonstrates the fabrication and utilization of tantalum oxide (Ta₂O₅) thin films as prominent pH sensing electrode material. Ta₂O₅ film of 1 μm thickness was deposited on glass substrates using physical vapor deposition technique. Structural and morphological studies were performed on these thin films. Electrochemical studies were carried out on these films using amperometry, linear sweep voltammetry and cyclic voltammetry techniques. These Ta₂O₅ coated substrates were found to be sensitive to various assorted pH solutions and hence were used as pH sensing electrode. The performance of the electrode was studied in terms of stability, reusability and selectivity. Results reveal that the films were found to be suitable pH sensing material in 1.0–12.0 pH range. The sensing electrodes were found to be reliable and reusable with less than 5 s response time.

In recent years, synthesis of TiC reinforced Cu matrix composites are comprehensively utilized for industrial applications. Synthesis of Cu-TiC as a thin film can also be an intriguing challenge for such applications. In this work, Cu-TiC thin film was deposited by DC magnetron co-sputtering method and examined to investigate the role of C content on the micro-structure, electrical conductivity and surface morphology by using XRD, UV–vis spectroscopy, I-V characteristics, AFM, SEM and EDX analysis. The wt% of C was varied from 14 to 67% while depositing the Cu-TiC films. All the films have resulted to be polycrystalline with Cu and TiC phases. The optical band-gap has decreased from 2.59 to 1.93 eV and the refractive index got enhanced from 2.92 to 3.38 with increase in wt% of C. The ideality factor, electrical resistance, surface roughness across the films has also decreased as wt% of C was increased in Cu-TiC films.

Electromicrofluidic (EMF) devices are used to handle and move tiny amounts of liquids by electrical actuation, including electrowetting-on-dielectric (EWOD) and dielectrophoresis (DEP). Monitoring the liquid characteristics in one of these devices requires suitable sensing transducers incorporated within the microfluidic structure. In the present work, we describe the incorporation of an optofluidic photonic transducer in an EMF device to monitor the refractive index of a liquid during its manipulation. The incorporated transducer consists of a responsive porous Bragg Microcavity (BM) deposited via physical vapor oblique angle deposition. Besides reporting the manufacturing procedure of the sensing-EMF device combining liquid handling and monitoring, the performance of the BM is verified by infiltrating several liquids dripped on its surface and comparing the responses with those of liquid droplets electrically moved from the delivery part of the chip to the BM location. This study proved that modified EMF devices can incorporate photonic structures to analyze very low liquid volumes (∼0.2 μL) during its handling.

In the present work polyethylene is used as a support of yttrium oxide particles doped with thulium atoms and its effect on the luminescent properties is studied. Thulium-doped yttrium oxide was prepared through the polyol method, different values of thulium are explored: 0, 0.5, 1, 1.5, 2.5 and 3.5 at%, as well as different calcinating temperatures: 400, 600, 800 and 1000 °C, are explored in order to determine the synthesis conditions needed for the maximum emission intensity, whose values were 1.5 at% of thulium and 1000 °C. The synthesized powder is dispersed in low-density polyethylene and dispersed as a thin film on glass substrates. The luminescent excitation and emission spectra showed important changes attributed to the influence of the -CH₂– chain vibration; in addition, the presence of the polymer had an important influence on the emission decay time: while the powder showed a single emission process with a time of 9.293 μs, the film showed a two decay process with 1.156 μs and 4.086 μs, each.

Thin films of Ru doped TiO₂ have been deposited on glass substrates at different doping concentration (0.05, 0.07, 0.09, 0.11 mol l⁻¹) by the sol gel method. The prepared thin films were studied: their structural, morphological, optical and photocatlytic properties. The XRD spectra confirm that all the samples have anatase phase with preferential orientation along (101) plane. The position of (101) peaks shift to higher angles with increase doping concentration and 0.07 mol l⁻¹ sample have a sharp and high intensity diffraction peak. Due to condensation and agglomeration effect. The thickness of the thin films increases from 110 nm to 255 nm with the increment of Ru concentrations. AFM images show that the films had good quality and pyramidal shape was distributed over their entire surface. Transmittance and absorbance spectra of the un-doped and Ru doped TiO₂ thin films were recorded by UV–vis spectrometer. The optical band gap of the thin films increases from 3.66 eV to 3.85 eV as the Ru amount increases; this is due to the Moss-Burstein effect. Calculated results show that both the excitation coefficient (k) and refractive index (n) decreases with wavelength at all Ru concentration. Optical conductivity can improve after doping which can be a suitable material for use in sensor and solar cell applications. The photocatalytic activity was investigated by monitoring the degradation of methylene blue (MB) under visible and sun light. The results revealed that the photocatalytic activity under sun light was higher comparing to UV light for all films. Ru doped TiO₂ thin films enhance the efficiency of its photocatalytic activity. It was found that the percentage of degradation was higher in 0.11 mol l⁻¹ Ru doped TiO₂ when compared with other films.

Amorphous germanium films with different thicknesses are deposited by magnetron sputtering (MS) method. Optical band gap and surface resistance are characterized. Our analysis reveals that there are three kinds of structural relaxation (SR) that may occur in amorphous germanium (a-Ge), and they are spontaneous SR (SSR), annealing-induced SR (AISR), and medium range order (MRO)-to-continuous random network (CRN) Sr Samples all demonstrate a band gap widening after these kinds of Sr The properties and mechanisms of SSR, AISR, and MRO-to-CRN SR are elucidated, respectively, which sheds some light on the controversies about SR in a-Ge films. In addition, some experimental results about SSR and AISR are also provided.

Disposable and highly efficient device that can separate oil from water is in high demand. This work reveals the concept of oil/water separation using plasma technology. Copper coated, oxygen plasma-treated mesh has been used to separate oil and water from its mixture. At some critical conditions, the prepared coated mesh showed hydrophobic and oleophilic behavior. The coated mesh was used to separate the oil-water mixture, which allowed the oil to pass through, while it repelled water completely. The designed coated mesh maintained separation efficiency as high as 99 percent. Properties of coated and uncoated mesh were examined using various techniques and analyzed to understand the physical changes.

Thin films of pure and Ti metal ion doped ZnO were grown on glass substrate by spray pyrolysis for various doping ratios keeping the temperature at 400 °C. Impact of Ti doping on morphological, optical and structural properties of ZnO was investigated. Structural confirmation of the thin-film was analyzed by using X-ray diffraction (XRD) studies and it concluded the successful growth of standard thin films of hexagonal wurtzite structure which was polycrystalline in nature. The morphological studies carried out using Scanning Electronic microscope (SEM), endorsed a uniform distribution of grain that are spherical in nature. Composition analysis by energy dispersive spectroscopy showed the presence of Ti, Zn and O in the films. Average grain size was estimated using Scherrer formula and obtained to be in the range of 35 to 50 nm. Atomic force microscopy was used to provide the surface roughness that had increased with the increase of Ti concentration. In the visible region, these films were found to be highly transparent and the average transmittance was obtained to be 85%. Photoluminescence spectral analysis showed a near band edge emission at 397 nm.

The biodegradability and mechanical properties of magnesium make it suitable for temporary implant applications. However, its degradation rate in the physiological environment needs to be controlled. The effect of grain refinement on the degradation rate in the physiological environment is investigated in this work. Samples with different grain size were developed by heat treatment and friction stir processing (FSP) techniques. Potentiodynamic polarization test in NaCl solution and immersion test in supersaturated simulated body fluid (SSBF) were conducted to evaluate the degradation resistance of the samples. The effect of grain refinement on biomineralization was also studied by analysing the surface morphology and composition of the immersion tested samples using SEM and EDAX. It is noted that the grain refinement improves the degradation resistance as well as biomineralization. The enhancement in the biomineralization resulted in the development of a calcium phosphate layer on the surface during the immersion test, which in turn reduced the degradation rate further. Hence grain refinement can be used as an effective metallurgical modification technique to tailor the degradation rate of Mg–Ca alloys in the physiological environment.

In this research, a systematic investigation of the properties of stoichiometric ultra-high temperature ceramics $Z{r}_{x}T{a}_{8-x}{C}_{8}$ is carried out. The mechanical properties including elastic constants, shear modulus, bulk modulus, Zener ratio, Poisson ratio, Pugh's index are calculated and then the hardness (H) and ${H}^{3}/{E}^{2}$ based on a semi-empirical approach are estimated. It exhibits that TaC possesses the lowest hardness equal to 22 GPa that increases to maximum hardness 30 GPa when a single Zr atom is substituted with Ta $(Z{r}_{1}T{a}_{7}{C}_{8}).$ Afterwards, the partial density of states (PDOS) of mentioned ceramics was calculated and plotted. Since the density of states at the Fermi level has some value, it is inferred that they all are electrical conductors. The p-d hybridization, the states at the Fermi level and the Mulliken charges of each atom indicate that the covalent, metallic and ionic nature of bonding exist simultaneously among constituent elements.

Tool nomenclature has a profound effect on the machining of alloys and the cutting force during machining. In this study, the effect of changes in radial rake angle of end mill cutter (+7°,0°, −7°) and machining parameters such as spindle rotational velocity (v) and table feed velocity ( f ) on cutting force and surface roughness were presented using regression analysis and a comparison has been made with the measured surface roughness and cutting force data. Additionally, to confirm the goodness of fit, Analysis of variance (ANOVA) has been undertaken and found that the developed empirical model is significant. The experimental outcome clearly indicates that the radial rake angle of end mill cutter is the most significant parameter, which reflect higher efficiency during machining followed by table feed velocity. Spindle rotational velocity is found to be a least significant parameter. Furthermore, the analysis of chip morphology confirmed the behavioral changes while machining due to the presence of variation in tool nomenclature and machining condition.

The influence of deep cryogenic treatment on the microstructure and properties of AlCrFe₂Ni₂ high-entropy alloy were studied by examining its phase composition, microstructure, and properties after cryogenic treatment. The results showed that as the cryogenic treatment increased, the alloy was composed of face-centered cubic (FCC) and body-centered cubic (BCC) phases. As the treatment time increased, the grain orientation of the BCC phase and B2 phase changed and transformed into each other, and the band FCC phase structures became shorter and more disordered. Deep cryogenic treatment effectively improved the hardness, yield strength, and wear resistance of the alloy. The alloy displayed the best performance with a holding time of 4 h, and the Vickers hardness (338 HV) was 11.6% higher than the as-cast alloy, and the yield strength (920 MPa) was 22.7% higher. The friction coefficient was 0.643, and the wear resistance was also significantly improved.

Al–based rapidly quenched alloys of composition Al₉₀Fe₇Nb₃ and Al₉₃Fe₄Nb₃ were studied by Mӧssbauer spectroscopy, X–ray powder diffraction and differential scanning calorimetry methods. The occurrence of thermally induced phase transformations has been established. It is shown that both ribbons reveal the structure in which Fe–atoms have an aluminum ones neighbors both in amorphous and annealed up to 653 K that corresponds to the atomic arrangement in Al₆Fe metastable phase. At higher than 709.6 K annealing temperatures the structural transformations of this phase into mix of stable Al₁₃Fe₄ compound and aluminium were observed and at 893 K these transformations were completed.

Here, it is found that the incorporation of rGO into (Sn_0.5Ti_0.5)O₂ solid solution suppresses spinodal decomposition via two characteristic routes. First, the addition of rGO to the solid solution leads to the compositional change from (Sn_0.5Ti_0.5)O₂ to (Sn_0.1Ti_0.9)O₂ moving out of the miscibility gap at SnO₂-TiO₂ phase diagram, which suppresses spinodal decomposition. The results indicate that addition of rGO promotes reduction and evaporation of SnO₂ during heat treatment. Secondly, the incorporation of rGO is found to produce the solid solution with lower Sn and Ti valences and more oxygen vacancies, which can also suppress spinodal decomposition.

In this paper, both the tensile deformation behaviors and mechanical properties of in situ ZrB₂ nanoparticles reinforced AA6016 matrix composites are investigated with finite element analysis. For the modeling, the volume fraction of nano ZrB₂ particles is defined by combining cluster sizes with particulate agglomerated degree which was observed in the agglomeration clustered regions by experiments. The effects of clusters on the mechanical behaviors of composites are disclosed according to qualify mechanical behaviors of local particulate agglomeration. The results indicate that finite element analysis is performed to predict the Young's modulus of composites, which is in good agreement with the experimental results. In addition, the speed of stress concentration is faster when the agglomerated degree elevates, which minimizes elongation of composites under the same particle volume fraction. Likewise, under the same agglomerated degree, the higher particle volume fraction of composites triggers the reduction of elongation.

The wear behaviour of the TiNi alloy tested at different conditions (2 and 4 N as applied loads and 40, 50 an 60 wt % as nickel contents) was investigated. For this purpose, two main experimental techniques consisting of wear and indentation tests were used. Scanning electron microscopy (SEM) and laser source profilometry were employed to reveal the wear mechanisms and the affected worn surfaces. Furthermore, design of experiments planning introducing factorial design as well as response surface was adopted to attempt predicting the coefficient friction according to the planned test parameters. Nanoindentation results showed that all the TiNi alloys are harder than a TA6V4 alloy which is commonly used in dental implant. Particularly, the TiNi60 alloy exhibited superior superelasticity, characterized by a lower E/H ratio and a higher depth recovery ratio than the TA6V4 alloy. Besides, the wear rates underwent a substantial increase with the increase of the applied load but a decrease with increasing the Ni content. The worn surfaces analyses revealed an enhanced resistance to adhesive and abrasive wear with increasing nickel content.

This study aims to investigate the effect of TiN inclusions on the fracture mechanism of 20CrMnTi steel with martensite. Size of martensite packets, blocks and TiN inclusions were characterized, and the room-temperature tensile properties, impact toughness and fracture toughness were tested of 20CrMnTi steel quenched at different temperatures. The effects of TiN inclusions on the impact toughness and fracture toughness were investigated according to the Hall-Petch relationship. The results show that, TiN inclusions are high temperature stable phases which insoluble to the matrix, mostly squared in shape and dispersed. The impact toughness and fracture toughness of 20CrMnTi steel decrease with increasing sizes of the initial austenite grains, martensite packets and blocks as the quenching temperature increases. Interestingly, the TiN inclusions strongly affect the toughness of the 20CrMnTi steel in the fracture and the fine-grained sample has a better toughness. Under high-stress concentrations, TiN inclusion particles can initiate cleavage cracking.

Fe-Cr alloys with different chromium contents have been designed in the current study for the ball mill liner working in weakly alkaline slurry. The structure, mechanical properties, corrosion behavior and erosion-corrosion behavior of the alloys were investigated. The result shows that with the increasing Cr content, the hardness and corrosion resistance of the alloy are improved. However, the impact toughness of the alloy shows a decreasing trend with the increase of Cr content. The alloy with the Cr content of 6.978 wt% exhibits the best erosion-corrosion resistance among all alloys in the weakly alkaline slurry. Further analysis shows that the erosion-corrosion mass loss of these alloys in weakly alkaline slurry mainly results from pure mechanical erosion and the interaction between corrosion and erosion. The damage process has also been discussed by interaction models of corrosion and erosion. The result is beneficial to provide reference for selection and development of erosion-corrosion resistant material for ball mill liner working in weakly alkaline medium.

The transformation of carbides in a 1.9Cr-1.4Mo-0.3 V secondary hardening steel that was subjected to over-ageing at 600 °C–700 °C has been investigated. The carbides were characterized using scanning electron microscope (SEM), x-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometry (ICP-AES), and transmission electron microscopy (TEM) preformed on carbon replicas. The results indicate that MC, M₂C, and M₃C were formed during over-ageing from 600 to 700 °C, whereas M₇C₃, and M₂₃C₆ started to be formed at 650 and 700 °C, respectively. In addition, the co-existence of hexagonal and orthorhombic M₇C₃ structures in a carbide particle was firstly observed. M₃C was transformed to other carbides, and the formation of both M₂C and M₂₃C₆ may follow the 'separate nucleation' mechanism, whereas M₇C₃ was transformed from M₃C via the 'in situ nucleation' mechanism. The crystallographic orientation relationships between the in situ transformed M₇C₃ and M₃C are ${(11\bar{2})}_{{{\rm{M}}}_{{\rm{3}}}{\rm{C}}}\,//\,{(3\bar{3}0\bar{1})}_{{{\rm{M}}}_{{\rm{7}}}{{\rm{C}}}_{{\rm{3}}}}$${\rm{and}}\,{[312]}_{{{\rm{M}}}_{{\rm{3}}}{\rm{C}}}\,//\,{[10\bar{1}3]}_{{{\rm{M}}}_{{\rm{7}}}{{\rm{C}}}_{{\rm{3}}}}.$

The 7075 aluminum alloy of the 7xxx series largely used for structures in modern aircraft has been successfully fabricated using selective laser melting (SLM) technology. The morphology of the initial 7075 aluminum alloy powders was characterized by a Zeiss Evo 50 Scanning electron microscope (SEM). Energy Dispersive x-ray (EDX) spectrometer attached to SEM was used as a tool to obtain the chemical composition of the powders. Processing parameters including scan speed, hatch distance and constant laser power (100 and 150 W) effect on densification, microstructure and hardness were investigated. The initial powder particles were found to be elongated and non-spherical and composed of Al, Zn, Mg, Cu, and Ag without Si. The result of the influence of processing parameters on properties of the as-built samples by SLM technology indicates that higher densification of parts can be gained using higher laser power and lower laser scan speed and hatch distance due to significant reduction in the number of pores. Two major types of pores including metallurgical and keyhole pores have been identified with the keyhole pores dominating the samples processed by low laser power of 100 W. The keyhole pores increase in size at a high scan speed and hatch distances. By using higher laser power of 150 W, the keyhole pores reduced significantly while metallurgical pores appear. The result of the hardness test conducted on the samples shows that high values of hardness can be achieved with low scan speed.

The 0.1C-18Cr-1Al-1Si ferritic heat-resistant stainless steel has attracted considerable attention to high-temperature applications due to its favorable combination of creep and oxidation resistance. In this paper, the microstructural evolution and precipitation behavior of the 0.1C-18Cr-1Al-1Si ferritic heat-resistant stainless steel is studied from the compression deformation data in the temperature range of 850 °C–1050 °C and the strain rate range of 0.01–1 s⁻¹. Experimental results demonstrate that higher temperatures and lower strain rates enhance the dynamic recrystallization (DRX) process with remarkable effectiveness. The main precipitates are proved as the AlN phases and the (Cr,Fe)₂₃C₆ carbides during hot deformation. With an increase in the deformation temperature, the size of (Cr,Fe)₂₃C₆ and AlN gradually increases, and volume fraction gradually decreases. When the strain rate decreases, the average size and volume fraction of (Cr,Fe)₂₃C₆ and AlN gradually increase. At the lower temperatures, the occurrence of dynamic recrystallization (DRX) is strongly influenced by (Cr,Fe)₂₃C₆ formed on the grain boundaries, mainly because it causes a pinning effect, which hinders the movement of dislocations and delays the occurrence of the DRX.

Herein, the effect of substitution of Ni with Ni₃Al and two-step sintering on the phase transformation, microstructure evolution, and properties of W–6Ni–4Co alloys were evaluated. The results show that the reaction products of Ni₃Al and Co include (Ni, Co)₃Al₄ to Co₂Al₉ during the two-step sintering process. When Ni was substituted by Ni₃Al, the densification temperature was reduced. The distribution of W phase turned from stripes to network, and the grain size increased with an increase in the sintering temperature. The Ni₃Al substituted sample sintered at 1500 °C for 20 min displayed a combination of high densification parameter, microhardness, and strength because of denser microstructure of the alloy.

In this paper, homogeneously dispersed TiC nanoparticles and fine-grained composite was successfully achieved by friction stir processing (FSP) of in situ 0.5 wt.% TiC/7085Al nanocomposites with different rotational speed. The effects of the rotational speed on the microstructures and tensile properties were investigated. Experimental results showed that the stir zone (SZ) exhibited equiaxed recrystallized grains with fine size and a high fraction of high-angle grain boundaries (HAGBs) caused by dynamic recrystallization (DRX). Moreover, the tensile strength and elongation of the friction stir processed (FSPed) composite were significantly improved compared with the base composite. With the rotational speed of 1000 rpm, the composite has the smallest grain size and the optimum mechanical properties. The average grain size decreased to 1.61 μm, the yield strength (YS), ultimate tensile strength (UTS) and elongation reached to 345 MPa, 429 MPa and 17.8%, respectively.

Owing to their high permeability, metallic soft magnetic materials exhibit high potential as microwave absorbers. The great challenge in designing desirable absorption properties from these materials is their large electrical permittivity at microwave frequencies. So, decreasing their permittivity within acceptable limits while keeping permeability at sufficiently high or improved levels is considered an important requirement for matching impedance and obtaining excellent electromagnetic (EM) absorption properties. In the present research, FeCo alloy particles produced employing by a simple wet chemical reduction process with the intention of investigating dependence of their EM properties on synthesis parameters. The characterizations were done with the help of x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The intrinsic EM properties (ε_r, μ_r) in a frequency range of 2–18 GHz were measured by a vector network analyzer (VNA) for the paraffin composites containing obtained products. The results indicated that the concentration of NaOH and metallic salts as the synthesis precursors can tune the permittivity and permeability. Under optimum conditions, bandwidths of 7.3 and 5.5 GHz with thicknesses of only 1.2 and 1.5 mm were obtained respectively. Also, Reflection loss (RL) of −45 dB was attained. The excellent EM absorption properties demonstrated that the synthesized FeCo alloy may be an ideal absorber having both a wide absorption bandwidth and a low thickness.

In this study, the corrosion behavior and corrosion resistance of TWIP (Twinning Induced Plasticity) steels in the industrial atmospheric environment were studied by dry-wet cycle immersion test and electrochemical experiments. The results showed that the corrosion rates of TWIP steel gradually decreased with the increase of corrosion time. A layer of corrosion products was formed on the surface of TWIP steel during alternating immersion accelerated corrosion process, whose main components were Fe₃O₄ and α-FeOOH. With the prolongation of corrosion time, the rust layer on the surface of TWIP steel had a certain protective effect on the steel matrix. The adherent and defect-free electroless nickel–phosphorus (Ni-P) coatings were prepared on TWIP steels. Electrochemical test results showed the corrosion current density of the coating was about six times lower than that of TWIP steel substrate, indicating that the coating effectively improved corrosion resistance of TWIP steel and protected the steel substrate from erosion of corrosive ions. Additionally, the surface microhardness of TWIP steel was significantly increased after electroless Ni-P plating treatment.

Casting is suggested to be a promising method to produce the low-cost ODS steel with large volume and high throughput. However, the ingot homogeneity of the cast ODS steel was rarely reported. Recently, our group prepared a castable ODS steel, which exhibited long creep life of 3800 h under 650 °C and 120 MPa. Thus the purpose of this work is presenting the homogeneity of the castable ODS steel. Theoretical addition of Y was 0.1 wt% thereby the steel was named as 9Cr-10Y. Nine samples were machined from the top, middle, bottom, left, center, right regions of this plate then subjected to homogeneity analysis. Y content, prior austenite grain size and second phase size of the nine specimens were 0.023–0.034 wt%, 9.27–0.94 μm and 294–314 nm, respectively. Low coefficient of variation (Cv) of 14.5% for Y content, 2.3% for prior austenite grain size and second phase size indicated that the homogeneous composition and microstructure were achieved in the 9Cr-10Y plate. Besides, hardness fluctuated within a small range and all the Cv values were in the range of 0.8%–4.3%, which demonstrated that the hardness distribution along RD, TD, and ND was homogeneous. Furthermore, the 9Cr-10Y plate exhibited high strength of 765 MPa and high elongation of 18.9% as well as low DBTT of −40 °C.

The Ti_xCrFeCoNiCu(x:molar ratio, ${\rm{x}}=0,\,0.2,\,0.5,\,0.8,\,{\rm{or}}\,1.0$) coating was depositd on aluminum by laser cladding. The phase structure, microstructure, hardness, wear resistance and corrosion resistance were studied. The results show that with the increase of Ti content, the phase structure of the Ti_xCrFeCoNiCu coating changes from single FCC to FCC + B2, and FCC + Laves phase. When Ti is increased to 1.0, cracks appear in the coating. The hardness of the Ti_xCrFeCoNiCu coating is enhanced with the increase of Ti content, and ranges from 215HV_0.2 to 585HV_0.2, which is about 3 to 7 times that of the substrate. The strengthening mechanism of Ti_0.2CrFeCoNiCu is solid solution strengthening, and when the Ti content is greater than 2, the strengthening mechanism of Ti_xCrFeCoNiCu coating is precipitation strengthening. The influence of Ti on the wear resistance exhibits the same trend as with hardness. When Ti increased from 0 to 0.8, the wear rate of the Ti_xCrFeCoNiCu coating changed from ${\rm{2.26}}\times {{\rm{10}}}^{-{\rm{4}}}\,{{\rm{mm}}}^{{\rm{3}}}\,{{\rm{Nm}}}^{-1}$ to $9.92\times {10}^{-7}\,{{\rm{mm}}}^{{\rm{3}}}\,{{\rm{Nm}}}^{-1}:$ smaller than the substrate. The addition of Ti increases the current corrosion density of Ti_xCrFeCoNiCu coating, but both coatings still exhibits superior corrosion resistance relative to the substrate.

Composite materials are being widely studied for the last few decades, and it has optimized the day to day applications in the engineering field. In this advancement, the use and development of metal matrices was a significant outcome that concentrated on the addition of many particulate materials in a metal matrix at nano and micro levels. Among these Magnesium, metal matrices are having a high potential, especially in transport, defense, and aircraft industries. Many research works are being carried out to use the capabilities of Magnesium and has provided excellent results. This paper is an overview of the development, processing, and improvement of properties in Magnesium alloys. Various manufacturing processes such as self-propagating high-temperature method, stir casting, laser cladding, and powder metallurgy has been used to develop the magnesium composites for increasing the properties by using various wt% of reinforcements added in the matrix. The improvement in mechanical properties such as tensile strength, yield strength, hardness and tribological properties such as wear rate is reviewed. The different properties and capabilities of Magnesium alloys such as AZ31, AZ91, and ZE41 is also discussed from the various research works.

The present study was undertaken to evaluate the effect of temperature, immersion time, and different corrosive media such as HCl, H₂SO₄ and KOH at different time intervals at 30 °C, 40 °C and 60 °C on the corrosion behavior of Fe and Ni-based alloy. The use of the design of experiment (DOE) and the analysis of variance (ANOVA) can be a useful methodology to reach this research. The analysis of the effects of each variable and their interaction on the corrosion of Fe and Ni-based alloys important role in selective best materials choice. The corrosion rate differs with different time intervals and different acid-base environments and increased with an increase in temperature from 30 to 60 °C. The study further reveals that the corrosion rate in different environment follows the order: HCl > H₂SO₄ > KOH.

Tungsten-nickel-manganese alloy is an excellent potential replacement of depleted uranium alloy for kinetic energy penetrator (KEP) due to its high self-sharpening effect. In this work, the 90W-4Ni-6Mn alloy was prepared by vacuum sintering, and the effects of the sintering temperature and oxygen content on its microstructure and properties were discussed. Sintering temperature had a great influence on the properties of tungsten heavy alloy. The optimal properties of 90W-4Ni-6Mn with the relative density of 99.43%, the W grain size of 3.80 μm, and the compressive strength of 2790 MPa were obtained at the sintering temperature of 1125 °C for 60 min under a vacuum of 10⁻²∼10⁻³ Pa. With the increase of oxygen content, the densification of powders became more difficult, and the microstructure homogeneity and mechanical properties of sintered samples decreased accordingly. The results provide a new effective way to prepare W–Ni–Mn alloy with high performance.

This work aims to investigate the effects of two welding techniques (gas tungsten arc welding (GTAW) with filler metal ER70S-3 and flux cored arc welding (FCAW) with filler metal E71T1C) on the microstructure and mechanical properties (including softening due to the conversion of martensite into tempered martensite) of DP steels with different martensite volume fractions ranging from 9 to 20%. Microstructure features and the constituents of base metals and heat affected zones of all weldments were examined and analyzed using an optical microscope and a scanning electron microscope integrated with energy-dispersive x-ray spectroscopy. Hardness, tensile, and v-notch impact toughness measurements were also carried out. Visual and radiographic inspection showed that both the FCAW and GTAW techniques produced sound weldments. However, DP steel weldments exhibited softening effects, which led to a decrease in joint efficiency. This decrease were related to transformation of the original martensite into tempered martensite. The results also revealed that the DP steel joints efficiencies are ranged from 85.9 to 87.7% using the FCAW process and ranged from 83.3 to 86% using the GTAW process. The impact toughness of the samples welded by FCAW is higher than the impact toughness of those welded by GTAW due to a higher percentage of acicular ferrite. This information should be valuable in the automotive and other industries, where DP steels are valued for their combination of high strength and ductility, which leads to weight savings and thus to reduced fuel consumption.

Mg matrix composites reinforced by graphene nanoplatelets (GNPs) offers an efficient approach for improving the mechanical properties of Mg alloys. Unfortunately, the poor uniform dispersion of GNPs into Mg matrix vastly restricts their development. In addition, surface oxidation of Mg alloy powders is always serious. To alleviate these issues, pickling and surface modification technologies of ZK61 Mg alloy powders and mixing process with GNPs have been investigated. The results show that ZK61 alloy powders with smooth surface and low degree of oxidation can be obtained after being simultaneously mechanically stirred and ultrasonically treated for 30 min in a 0.2 vol% HF ethanol solution. They were then rinsed and dried, and modified by 0.3% wt% cetyl trimethyl ammonium bromide to carry a positive charge. Subsequently, GNPs ethanol suspension was poured into the modified ZK61 alloy powders solution and mechanically stirred for 10 min, and then a powder mixture that GNPs randomly attached on the Mg powders was obtained after drying.XPS analysis reveals that GNPs were adsorbed on the surfaces of the modified Mg powders by the mechanism of electrostatic adsorption. The achieved method for preparing GNPs/ZK61 alloy mixture powders provides a new strategy for fabricating Mg matrix composites reinforced by uniformly distributed GNPs.

An investigation was conducted on Al-4%Cu alloy sheets to study the role of deformation path on the strength properties, evolution of microstructure and crystallographic texture during cryogenic rolling. Samples were rolled to two distinct thickness strains (50% and 75%) by unidirectional and cross rolling (bidirectional) routes. The strength and hardness properties were found to be more efficient in the cross rolled samples at 50% reduction than their counterparts rolled unidirectionally. Dynamic recovery was observed at higher rolling reductions on cross rolling. Microscopic features observed by EBSD revealed the occurrence of significant grain refinement on the samples rolled with a change of strain path. Also, the alteration of the rolling route resulted in distinct deformation textures and microstructures. TEM studies pointed out the scattered diffusion of the disintegrated dislocation cores and the redistribution of the second phase particles on higher rolling reductions with the change of strain path. Furthermore, the texture results showed a threefold increase on the Goss/Brass ratio which indicated the good fracture toughness behaviour of the cross rolled samples at lower reductions.

The Al-11.0Mg-2.6Si-4.0Zn-0.6Mn (wt%) alloy is a new developed high strength die cast alloy which can be used for structural parts in the automotive and aerospace industry. In this study, the effect of various amount of Ti on microstructure evolution and mechanical properties of Al-11.0Mg-2.6Si-4.0Zn-0.6Mn (wt%) alloy under as-cast and T6 heat treatment conditions are investigated. The addition of Ti results in the formation of Al₃Ti intermetallic phase, and the volume fraction and forming temperature increases with the increase of titanium content. With 0.1wt% Ti addition, the best mechanical properties of the alloy. The yield strength (YS), ultimate tensile strength (UTS) and elongation reach up to 350 MPa, 440 MPa and 3.29% respectively after heat treatment. Titanium content should be controlled below 0.10%.

In this paper, the corrosion behavior of X80 pipeline steel weld joints in an acidic red soil solution was studied. The results show that uniform corrosion occurs on the entire surface of the weld joint after 840 h immersion. The corrosion degree of heat affected zone (HAZ) is more serious than that of base metal (BM) and weld zone (WZ). The corrosion rate of HAZ specimen is always higher than those of WZ and BM specimens throughout the separated immersion. The accelerating corrosion of HAZ may come from its microstructure change, its corrosion sensitivity and the deterioration of mechanical performance of corrosion product on it.

In this paper, WC-10Co4Cr coating was prepared on the surface of LC9 aluminum alloy by high velocity air-fule (HVAF) process. And a thermal deformation method was developed to enhance the coating properties. Experimental results show that, during the process of thermal deformation, the increase of temperature and deformation amount could improve the microhardness of coating surface. With temperature of 480 °C and deformation amount of 16% (0.8 mm), the microhardness reached the maximum value of 1349 HV0.3, which increased nearly 20% compared with that of specimen (1137 HV0.3) without compressive deformation. Besides, the strengthening effects of thermal deformation temperature and deformation amount on the bonding strength of coating were obvious. With deformation temperature of 450 °C and deformation amount of 8% (4 mm), the bonding strength reached the maximum critical load of 188 N, which was 17.5% higher than that of initial state.

The corrosion behavior and microstructural changes in explosively welded AA5083/AA1050/SS 321 multilayer tubes after heat treatment were studied. Heat treatment were performed in 350 and 450 °C for 6 and 8 h. Microscopic results indicated significant changes in the thickness and concentration of alloying elements in locally melting zone with heat treatment temperature. According to electrochemical tests results at samples interfaces, by increasing the temperature and time of the heat treatment process, the energy stored due to explosive welding is reduced, the difference in the concentration of aluminum related to steel in the interface layer decreases, and the corrosion rate (current density) and electrical charge transfer decrease.

In this work, four Mg-Y-Zn alloys with specific Y/Zn (wt%) ratio have been prepared. The effects of Y/Zn (wt%) on the microstructure of extruded Mg-Y-Zn alloy were investigated by SEM and TEM. The mechanical properties and corrosion behavior of extruded Mg-Y-Zn alloy were also studied by tensile test, electrochemical and immersion measurements. The corrosion mechanism was studied by SEM observation of the surface morphology of the samples after immersion corrosion. The result indicates that the as-extruded Mg-6Y-3Zn alloy consists of α-Mg, W phase and long-period stacking ordered structure (LPSO) phases. Two types of LPSO structure (18 R and 14 H) appear in the as-extruded alloys. The volume fraction of LSPO increases with the increase of Y and Zn atoms witht the same Y/Zn mass ratio. Mg-9Y-3Zn alloy has the best comprehensive mechanical properties. Its yield strength, ultimate tensile strength and elongation are 230 MPa, 327mpa and 23% respectively, because the volume fraction of LSPO phase in the alloy is the highest. In addition, the higher volume fraction of LPSO is beneficial to enhance the corrosion resistance of Mg-9Y-3Zn alloy.

This research paper describes the enhancement of mechanical, wear and corrosion behaviour of the Copper (Cu) matrix composite by reinforcing Fly ash (FA) and Tungsten (W). The main objective of this study was to reduce the weight and cost of the hybrid composites. The weight percentage of low density material (FA) was kept constant at 6% and samples were prepared by the addition of W in weight percentages of 3, 6 and 9 in the Cu matrix. The characterization of the hybrid composites was studied using a Scanning Electron Microscope (SEM) and Energy-dispersive spectroscopy (EDS). The micrographs revealed the uniform distribution of W and FA in the Cu matrix. From the mechanical characterization, it was identified that there is an increase in microhardness and compressive strength with the addition of W particles. It can be understood that the W particles occupy substitutional type reinforcement and FA particles occupy interstitial type reinforcement in the Cu matrix. The Wear behavior and its mechanism were studied using worn surface SEM micrographs. It was observed that the lowest specific wear rate was recorded for the hybrid composition of Cu-6FA-6W. Electrochemical polarization test and Electrochemical Impedance Spectroscopy (EIS) study revealed that Cu-6FA-9W shows higher corrosion resistance in both 1 N HCl (256.593 × 10⁻⁴ Ω cm²) and seawater media (219.855 × 10⁻⁴ Ω cm²) than pure Cu.

The effects of rare earth Ce on the microstructure, mechanical properties and corrosion behavior of Al-Cu-Mn-Mg-Fe alloys were investigated by means of microstructure analysis, tensile test and electrochemical corrosion test. The research shows that the Al-Cu-Mn-Mg-Fe alloy after low temperature heat treatment mainly contains the S (Al₂CuMg) phase, the T (Al₂₀Cu₂Mn₃) phase, the Al₆ (Mn, Fe) phase and the Al₇Cu₂Fe phase, and the rare earth Ce makes the alloy form the new rare earth phase Al8Cu4Ce. The appearance of this phase has a significant refinement effect on the Al₆ (Mn, Fe) phase. Compared with Ce-free, the yield strength and tensile strength of Al-Cu-Mn-Mg-Fe alloy with 0.254 ωt% Ce increased by 7% and 15%, respectively, and the elongation increased from 3.1% to 4.8%. It also has better corrosion resistance, which is represented by the decrease of corrosion current density and positive shift of corrosion potential in Tafel measurement in solutions of different concentrations, and the increase of corrosion impedance in electrochemical impedance spectroscopy test, especially the corrosion current density was reduced by 6.06 μA cm⁻² in 3.5% NaCl solution.

In this study, the effect on the structure stability, elastic properties and electronic structure of P-doped Mg₂Si were studied by the first-principles pseudopotential plane wave method based on density functional theory. The lattice constants, formation enthalpy, cohesive energy, elastic constants, and elastic moduli of Mg₂Si, Mg₇Si₄P, Mg₈Si₃P and Mg₈Si₄P were calculated, and the electronic structure analysis was also performed. The occupation tendency, structural stability, bonding characteristics, orbital hybridization and the change of conductivity of doping P atoms in the matrix were further investigated. Among them, the research results of formation enthalpy, cohesive energy and elastic constant show that Mg₂Si, Mg₈Si₃P and Mg₈Si₄P can all exist stably in the system, and the crystal structure of Mg₇Si₄P can not exist stably. P atoms doping into the Mg₂Si lattice tend to occupy Si atoms position preferentially. The results of elastic modulus study show that Mg₂Si and Mg₈Si₄P are brittle phase and Mg₈Si₃P is ductile phase. The plasticity and toughness of Mg₂Si alloy system are improved by doping P atoms. The electronic structure analysis shows that the method of doping P atoms changes the orbital hybridization and bonding characteristics of the system. The Mg-P and Si-P covalent bond formed by Mg₈Si₃P and Mg₈Si₄P increase the structure stability. The energy band structure analysis also show reduction of the band gap from 0.224 to 0.184 eV for Mg₂Si with P dopants at the substitutional Si-sites and the band gap closure in the system with interstitial P-impurities. It enhances the metallic property of the material, and Mg₈Si₄P phase also transform from its semiconducting to metallic state. Consequently, this method both increases the carrier concentration and reduces the energy of free electron transition. The conductivity of the Mg₂Si alloy system will be improve.

While particulate-reinforced metal matrix composites are composed of two phase materials with dramatically different physical and mechanical properties, sound wave-particle interactions play an important role in their ultrasonic inspection tests. In the present work, we investigate the sound wave-particle interactions in silicon carbide (SiC) particle-reinforced aluminum (Al) matrix composites under the pulse-echo mode ultrasonic inspection by means of finite element simulations. Be consistent with experimentally observed real microstructures, the simulated SiC particles have polygon shapes and are randomly dispersed in the Al matrix. In particular, the sound wave-particle interactions are revealed, and their correlations with the A-scan signals are investigated. Furthermore, the effects of extrinsic pulse frequency and intrinsic SiC particle size on the ultrasonic inspection of the composites are addressed. Simulation results indicate that the interference of sound waves with heterogeneous SiC particles leads to more pronounced deflection, scattering and conversion of sound waves than the pure Al matrix, which in turn result in higher attenuation of sound waves in SiCp/Al composites. It is also found that the sound wave-particle interactions have a strong dependence on both pulse frequency and particle size.

The physical characters that belong to hypo-eutectic Al-Si alloys are affected by certain important factors including the dimension, distribution together with structure of eutectic Si crystals together with primary α-Al. In this paper, A356-x Al-5Ti-0.62C-1.07La (x = 0, 4, 5, 6, 7 wt%) alloys are was prepared by mechanical stirring. The effects of Al-5Ti-0.62C-1.07La intermediate alloy on the microstructures and mechanical properties of A356 alloy are investigated. Results show that the primary α-Al was significantly refined by Al-5Ti-0.62C-1.07La intermediate alloy. The secondary dendrite arm space (SDAS) of unrefined α-Al is approximately 40 μm. When the substance of Al-5Ti-0.62C-1.07La intermediate alloy is 6 wt%, SDAS declines to 10 μm. In addition, the component part of eutectic Si turns from thick acicular/schistose to short rod-like together with a section of pellets. Adding 6 wt% Al-5Ti-0.62C-1.07La intermediate alloy, A356-T6 alloy obtained the best tensile function and hardness. The ultimate tensile strength (UTS), elongation (El) together with Vickers hardness (HV) are 183.5 MPa, 8.2% and 62.3, which is increased by 30.3%, 95.2% and 38.1%, respectively. Furthermore, the variation in mechanical properties change with the development of micro-structure.

The effects of Ce on the microstructure of Zn-5.5Al-4.5Mg alloy and the corrosion mechanism of Zn-5.5Al-4.5Mg-0.3Ce alloy and its coatings were investigated in this research. The results show that the structure of Zn-5.5Al-4.5Mg-0.3Ce alloy is composed of hcp-Zn, fcc-Al and ternary eutectic structure (Zn/Al/MgZn₂/Mg₂Zn₁₁), without dendritic tissue and MgZn₂. The salt spray corrosion performance of Zn-5.5Al-4.5Mg-0.5CMC-2C coating was significantly better than that of Zn-5.5Al-4.5Mg-0.3Ce coating and Zn-5.5Al-4.5Mg-0.5CMC coating. The corrosion current density of Zn-5.5Al-4.5Mg-0.5CMC-2C coating was 3.217 μA cm⁻², which was significantly lower than 3.96 μA cm⁻² of Zn-5.5Al-4.5Mg-0.3Ce alloy and 5.879 μA cm⁻² of Zn-5.5Al-4.5Mg alloy. Sodium carboxymethylcellulose and graphene improve the film formation and electrical conductivity of water-based lithium silicate resin. During corrosion of Zn-5.5Al-4.5Mg-0.3 Ce series alloy and coatings, Zn and Mg₂Zn₁₁ dissolved preferentially to form corrosion products of Zn₅(OH)₆(CO₃)₂ and Zn₅(OH)₈Cl₂·H₂O. Mg₆Al₂(OH)₁₆CO₃·4H₂O and Zn₄Al₂(OH)₁₂CO₃·3H₂O bimetallic hydroxide colloidal membranes were formed, which attached and wrapped on the surface of early corrosion products. Mg₆Al₂(OH)₁₆CO₃·4H₂O and Zn₄Al₂(OH)₁₂CO₃·3H₂O, preventing the dissolution of soluble corrosion products, improved the corrosion resistance of Zn-5.5Al-4.5Mg-0.3Ce alloy.

In this paper, a novel method was proposed to measure the residual stress and plasticity parameters of metal materials with yield plateau through continuous spherical indentation test. The indentation energy was selected as the indentation parameter to establish a dimensionless equation between the residual stress and material parameters through dimensional analysis method. The effects of residual stress and plastic parameters on the indentation response tests are studied, and the dimensionless function expressions are determined respectively when the specimen with or without residual stress based on the finite element analysis data of different residual stress levels. Based on the self-established inverse analysis, the yield strength (${\sigma }_{y}$), strain hardening exponent (n), ratio coefficient (a) and residual stress (${\sigma }_{r}$) can be obtained through indentation test. At last, the validation of the method presented in this paper was verified by simulating the material (SS400 and SM490) with the known material parameters.