Thermo-physical and mechanical properties of Yb2O3 and Sc2O3 co-doped Gd2Zr2O7 ceramics

摘要

Ceramic materials for the thermal barrier coating (TBC) application of Gd2Zr2O7 (GZO), (Gd0 .94Yb0.06)(2)Zr2O7 (GYb(0.06)Z), (Gd0.925Sc0.075)(2)Zr2O7 (GSc(0.075)Z), (Gd0.865Sc0.075Yb0.06)(2)Zr2O7 (GSc(0.075)Yb(0.06)Z), and (Gd0.8Sc0.1Yb0.1)(2)Zr2O7 (GSc(0.1)Yb(0.1)Z) were successfully synthesized by chemical co-precipitation. The effects of the doping of Sc2O3 and Yb2O3 on the phases, thermo-physical and mechanical properties of the ceramics were investigated. The results show that both Yb2O3 and Sc2O3 doping promoted the phase transition of GZO from pyrochlore to fluorite. All the Sc2O3-doped samples exhibited enhanced fracture toughness, as compared to the undoped sample. Furthermore, the GSc(0.075)Yb(0.06)Z sample revealed a thermal conductivity of similar to 0.8 W/mK at 1200 degrees C, which was nearly 30% lower than that of the undoped sample. The associated mechanisms related to the effects of the doping on the thermophysical and mechanical properties are discussed.