ZTA Hardness Enhancement via Hot Isostatic Press Sintering

Abstract

The present work mainly deals with the influence of Y2O3 stabilize ZrO2 (YSZ) additions on the phases, microstructure and mechanical properties of Al2O3 which is known as zirconia toughened alumina (ZTA) through hot isostatic press (HIP) sintering. Different amounts of 8 mol% of yttria stabilize ZrO2 (8YSZ) were added into Al2O3 and the amount of 8YSZ was varied from 0 wt.% to 25 wt.%. There is significant evidence that microstructural coarsening within ZTA was found to produce an improvement of hardness and fracture toughness. These improvements are the evidence for the toughening mechanism through the transition of tetragonal to monoclinic (t-m) structure provide by 8YSZ which is defined to optimize the materials and mechanical properties of Al2O3 ceramics. The 8YSZ grains and Al2O3 grains are impartially distributed among each other. The XRD patterns are corresponds to yttria doped zirconia (Zr0.935Y0.065)O1.968 peaks (ICDD files No. 01-078-1808) and Al2O3 (No. 00-010-0173). The existence of (Zr0.935Y0.065)O1.968 phase relates to the metastable tetragonal form of ZrO2.