Influence of Y3Al5O12 doping on mechanical properties and thermal conductivity of Sm2Zr2O7-Y3Al5O12 composite ceramics

Rare earth zirconates are considered as one class of the ideal candidate high-temperature structural materials. In this paper, a series of Y3Al5O12 doped Sm2Zr2O7 [(1-x)Sm2Zr2O7-xY3Al5O12, x = 0, 0.05, 0.1, 0.2, 0.3, mol.%] composite ceramics were prepared at 1600 degrees C. The influence of Y3Al5O12 doping on microstructure, mechanical properties and thermal conductivity of Y3Al5O12 doped Sm2Zr2O7 were investigated. The results showed that the composite ceramics were mainly composed of Sm2Zr2O7, Y3Al5O12 and a small amount of SmAlO3 phases. The grain size of Sm2Zr2O7 in composite ceramics obviously decreased with the increase of Y3Al5O12 doping concentration. The fracture toughness of 0.8Sm(2)Zr(2)O(7)-0.2Y(3)Al(5)O(12) composite ceramic was (2.50 +/- 0.14) MPa.m(1/2), which was the highest among the investigated ceramic materials, and was about twice as high as that of pure Sm2Zr2O7 ceramic. The thermal conductivity of composite ceramics increased with the rise of Y3Al5O12 doping concentration at above 600 degrees C. 0.8Sm(2)Zr(2)O(7)-0.2Y(3)Al(5)O(12) composite ceramic had almost no change in grain size and phase composition before and after sintering at 1400 degrees C for 100 h, suggesting that 0.8Sm(2)Zr(2)O(7)-0.2Y(3)Al(5)O(12) composite ceramic had good sintering resistance at 1400 degrees C. (c) 2020 Elsevier B.V. All rights reserved.