Study of Elastic Modulus and Roughness of Porous Alumina Toughened Zirconia

Alumina Toughened Zirconia (ATZ) composite with 20 wt% alumina has been prepared by powder compaction method after stabilized zirconia using 3 mol. of yttria to get the 3Y-TZP compound. A graphite additive (0,10,20,30, and 40) wt.% have been added to produce porous ATZ. The composite has been sintered in the air at 1500 °C. The effect of porosity on physical and structural properties have been investigated. Porosity increased, and bulk density decreased with graphite additives increases in the range (7.5-51.7) % and (5.6-2.8) g/cm³ respectively for (3Y-TZP/20 wt% Al₂O₃) specimens. The porosity effect is apparent by deteriorating the mechanical properties; the diametric strength decreased from 95.7 to 8.7 MPa, while the young modulus decreased from 159.7 to 27.3 GPa with porosity increases. Surface morphology was detected by atomic force microscope (AFM). The average grain size and roughness of 3Y-TZP/20 wt% Al₂O₃ specimens increased with increasing porosity from 75.44 to 91.9 nm and 2.9 to 18.7 nm, respectively. It was found that porous ATZ was successfully fabricated by using graphite additives. The apparent porosity of 3Y-TZP/20 wt% Al₂O₃ composite after sintering can be controlled by the amount of graphite content in the powder mixture. The presence of porosity greatly influences physical and microstructural properties.