Thermal Stability of Partially Stabilized Zirconia

Abstract

Recent syudies on the thermal stability of zirconia ceramics were summarized. Although yttriadoped tetragonal zirconia polycrystals (TZP) show excellent mechanical properties, the fracture strength was greatly degraded by annealing at low temperature such as 200°C in air. This is due to the formation of microcracks accompanied with the tetragonal to monoclinic phase transformation. The phase transformation was induced by the chemical reaction between ZrO₂ and H₂O adsorbed on the surface. The thermal stability of TZP could be improved by decreasing the grain size of zirconia, dispersing Al₂O₃ and alloying with CeO₂.