Effect of Temperature and Holding Time on Zirconia Toughened Alumina (ZTA) Prepared by Two-Stage Sintering

The microstructure and mechanical properties of Zirconia Toughened Alumina (ZTA) produced via two-stage sintering at various sintering temperature of T 1 and T 2 in addition to effect of various holding time were investigated. T 1 temperature was set between the range of 1400°C to 1500°C with a heating rate of 20°C/min. The samples were then sintered at T 2 ranging from 1350°C to 1400°C followed by various holding time between 2 hours to 12 hours. The sintered samples’ microstructural properties, bulk density, hardness (Vickers hardness), elastic modulus (Young’s modulus) and fracture toughness (K 1C ) were then determined. Compared to standard holding time of two-stage sintering which is 12 hours, results show that ZTA produced via two-stage sintering with shorter holding time of 4 hours with T 1 set at 1500°C and T 2 of 1450°C are capable of achieving full densification. In addition, the same sample were also able to achieve hardness up to 19 GPa, Young’s modulus of 390 GPa and fracture toughness of 6.1 MPam 1/2 . The improvement in mechanical properties can be mainly attributed to the absent of surface diffusion at T 2 above 1400°C and also presence of Y-TZP which contributed to lower grain growth due to the pinning effect.