Published online by Cambridge University Press: 25 February 2011
Yttria-doped tetragonal zirconia polycrystals (Y-TZP) containing 2 and 3 mol% of Y2O3 uniformly alloyed by 0-15 mol% of CeO2 or diffusing CeO2 on the surface were fabricated, and the mechanical properties and thermal stability of the sintered bodies were evaluated by annealing in humidity conditions at 50–600° C. The tetragonal-to-monoclinic phase transformation proceeded at 100–500°C in air, and accompanied microcracks. The phase transformation proceeded rapidly on the surface, but slowly inside the body. The bending strength of the annealed specimens depended on the depth of the transformation layer thickness, but not on the degree of the phase transformation on the surface. Alloying CeO2 was useful to improve the thermal stability of Y-TZP, but noticeably decreased the fracture strength. Diffusing CeO2 on the suface of Y-TZP seemed to be useful to improve the thermal stability without loss of the fracture strength.