Influence of sintering profile on the mechanical properties of manganese oxide doped 3Y-TZP

Abstract

Zirconia ceramic has been identified as one of the advanced ceramic material with great mechanical properties which is used as engineering and implant materials. However, the great potential of the ceramic is hindered by low temperature degradation (LTD) where the ceramic experiencing t-m phase transformation that weakens the properties of 3Y-TZP in the presence of moisture. Two-step sintering was found to be effective in producing fully resistance 3Y-TZY but very long holding time is required. Manganese Oxide (MnO2) is reported as good densification aid at low sintering temperature for 3Y-TZP but the LTD issue is not fully resolved. In this study, the effects of different sintering profiles and dwell time on 3Y-TZP added with 0.5 wt.% of MnO2 were studied in order to improve the resistance towards LTD without affecting the intrinsic properties of the ceramic. The effects of adding 0.5 wt.% of manganese oxide (MnO2) into 3 mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) were studied using different sintering profiles and dwell time. The samples were sintered at 1400°C and 1250°C with varying dwell time of 1 min and 2 hours for single step sintering and a combination of 1 min and 30 min, 2 hours and 25 hours for two step sintering. The optimal sintering profile was Profile C2 where doped 3Y-TZP undergone two step sintering with dwell time of 1 minute at 1400°C and 1250°C for 30 minutes. At this optimal sintering conditions, the doped 3Y-TZP samples exhibited 98.5% relative density, with Young’s Modulus of 206.66 GPa and Vicker’s Hardness of 14.35 GPa.

Sintering mechanisms of partially stabilized zirconia (TZ3Y) with ZnO and Co3O4 as sintering additives

“…There are several sintering additives that can be used for the densification of yttria-stabilized zirconia. Typically, they are composed of transition metal oxides, which decrease the sintering temperature by up to 200 °C [2][3][4][5][6][7]. Generally, there are two theories of the role of oxide sintering additives during processing.…”