Thermal shock resistance of fiber dispersed ZrO₂ ceramics - influence of Y₂O₃ content of matrix -

Influence of Y₂O₃ content on the thermal shock resistance of ZrO₂Y₂O₃ ceramics including 12vol% of ZrO₂Y₂O₃ fiber was investigated by varying the content of Y₂O₃ from 1.5 to 8.0mol%. After specimens were sintered at 1300°, 1400° and 1500°C for 2h, bending strength, fracture toughness, thermal conductivity, and thermal expansion coefficient were measured. Thermal shock resistance was characterized by strength degradation before/after thermal shock experiment (quenching temperature difference: ΔT = 600K), and it was increased as the Y₂O₃ content was decreased. It is considered that this is due to the decrease in thermal expansion coefficient caused by the increase in monoclinic phase in the matrix, and the increasing of fracture toughness.