Effect of 45S5 bioactive glass on the sintering temperature of titanium-hydroxyapatite composite

Titanium (Ti) is widely known for its good mechanical properties and corrosion resistance. However, it has poor biocompatibility. Hydroxyapatite (HA) is a biocompatible material but has poor mechanical properties. Making Ti-HA composite creates a promising choice of biomaterial in dental and medical applications. However, creating a Ti-HA composite requires sintering at high temperatures which leads to oxidation of Ti. The aim of this study was to reduce the sintering temperature of Ti-HA composite by incorporating 45S5 Bioactive Glass (BG) without compromising the chemical, physical and mechanical properties of the composite. In this study, a Ti-HA-BG composite with wt% of 45-45-10 respectively was produced via powder metallurgy. This was compared with the control composite consisting of 50 wt% Ti- 50 wt% HA. Powders according to the above-mentioned ratio were milled at 200 rpm for 5 hours by using a planetary ball milling machine. Samples were then compacted into cylindrical pellets via uniaxial pressing at 1500 psi and sintered in an atmospheric furnace at 1000 °C, 1100 °C and 1200 °C for 4 hours. Ti-HA and Ti-HA-BG sample characteristics were examined and compared by using Fourier Transformed Infrared Spectroscopy (FTIR), Energy Dispersive X-Ray (EDX) and X-Ray Diffraction (XRD). The density and volumetric expansion of the composites were also measured and compared. Results from XRD data indicate the reduction of oxidation of Ti and decomposition of HA in Ti-HA-BG composite at lower temperature in comparison to Ti-HA composite. The density of Ti-HA-BG composites are higher compared to Ti-HA composite while the volumetric expansion of Ti-HA-BG composites is lesser than Ti-HA composite. Therefore, BG is a low melting point additive that acts as a good sintering aid to effectively lower the sintering temperature while maintaining the desired properties of initial components.