���膨張材料を分散させた表面層を持つセラミックス積層体の耐熱衝撃性

Layered ceramics with composite surface layers were prepared using Ce2Zr3(MoO4)9 (CZM), a low-temperature sintering ceramics, as the matrix and ZrW2O8, a negative expansion material, as the dispersoid. Their thermal shock resistance properties were compared with those of the monolithic matrix and similarly prepared layered ceramics with alumina or zirconia dispersed composites layers. Bending strength before thermal shock was measured, and no significant increase in strength was observed with the addition of ZrW2O8, and no systematic relationship was observed between the thermal expansion coefficient difference of the matrix and dispersoids in the composites prepared in this study. On the other hand, thermal shock fracture tests showed that the addition of ZrW2O8 increased the critical temperature difference (∆Tc) from 100°C to 150°C compared to monolithic CZM, indicating an improved thermal shock resistance. The critical temperature difference tended to increase with decreasing the coefficient of thermal expansion of the added dispersoids.