Thermal Cycling Behavior of Sm2Zr2O7 Ceramics Thermal Barrier Coatings by APS

The prochlore structure ceramic of Sm2Zr2O7 was synthesized by chermical coprecipitation method. Then the feedstock powder for plasma spraying was prepared by spray drying with proper distribution of particle size about 30–70μm. The thermal barrier coatings with a topcoat of Sm2Zr2O7 and with a two– layer topcoat of Sm2Zr2O7/YSZ were prepared by atmospheric plasma spraying(APS). The cohesive strength of Sm2Zr2O7/YSZ coating presented a value of 15.49 Mpa and 23.37 Mpa, respectively. Microstructure and phase analyses reveal that plasma spraying of complex Sm2Zr2O7 is accompanied with the formation of the transverse crack networks. the TBCs with topcoat of Sm2Zr2O7 and Sm2Zr2O7/YSZ performed a thermal cycles of 35 and 60 separately under the test temperature of 1100°C. The thermally grown oxide at the topcoat–bondcoat interface was also the major factors that lead to the coating failure on thermal cycling at about 1100°C.