Effects of Er3+ doping on structure and thermal properties of (Sm1–xErx)2Zr2O7 ceramics for thermal barrier coating

Abstract

Rare earth Er3+ doped (Sm1–xErx)2Zr2O7 (x = 0.1, 0.2, and 0.3) ceramic samples were synthesized using a solid state reaction method. The microstructure and thermal properties of these ceramics were investigated to evaluate their potential as thermal barrier coating materials. The results show that ceramics are compact with regular-shaped grains of 1–5 μm size. (Sm1–xErx)2Zr2O7 has a pyrochlore structure mainly determined by ionic radius ratio, but the ordering degree decreases with increase of the Er2O3 content. There is no phase transformation from 1000 to 1200 °C, and the (Sm1–xErx)2Zr2O7 ceramics exhibit excellent phase stability during thermal treatment at 1200 °C for 100 h and 1400 °C for 50 h. The thermal conductivities of dense (Sm1–xErx)2Zr2O7 ceramics range from 1.52 to 1.59 W/(m·K), which is lower than that of Sm2Zr2O7, and decrease as the Er2O3 content increases. Besides, the thermal expansion coefficient of (Sm1–xErx)2Zr2O7 is higher than that of Sm2Zr2O7.