Effects of TiO2 addition on the phase, mechanical properties, and microstructure of zirconia-toughened alumina ceramic composite. Issue 3 (April 2015) - Manshor, Hanisah
Abstract: Ceramic composite made up of zirconia-toughened alumina (ZTA) with TiO2 as additive was constructed via a solid-state sintering route. The Vickers hardness of the obtained ZTA–TiO2 was evaluated at various levels of the TiO2 addition. Every sample was dry mixed, uniaxially pressed and sintered at 1600 °C for 1 h in a pressureless condition. The presence of TiO2 was observed to have greatly influenced the microstructure of the Al2 O3 . Grain growth of the Al2 O3 particles was hindered with the addition of 3 wt% TiO2, but increased in size at an excess of 3 wt% TiO2 . According to the results, tialite (Al2 TiO5 ) begun appearing at a composition of ZTA–5 wt% TiO2 and this increased with the TiO2 content. The fracture toughness and hardness were enhanced from 5.93 MPa √m (0 wt% TiO2 ) to 6.56 MPa √m (3.0 wt% TiO2 ) and from 1516.13 HV (0 wt% TiO2 ) to 1615.8 HV (3.0 wt% TiO2 ), respectively. The improved bulk density from 3.9 g/cm 3 (0 wt% TiO2 ) to 4.10 g/cm 3 (3.0 wt% TiO2 ) resulted from the fine microstructure, thereby enhancing the mechanical properties.