Ceramics in Engines-Long Term Stability of Transformation Toughened Zirconia

The long term thermal stability of two types of magnesia partially stabilized zirconia at temperatures below 1000°C has been determined. The effect on mechanical properties and phase stability of isothermal heating at 800°C and 900°C for up to 2000 hours, and with thermal cycling for a similar period between R.T. and 800°C in air, was measured. It was found that peak-aged (MS) type Mg-PSZ was much more stable than the thermal shock resistant (TS) type in both tests and showed minimal degradation.