Microstructural Evolution And Thermal-Physical Properties of Ytao4 Coating after High-Temperature Exposure

Abstract

YTaO4 spherical powders were synthesized via centrifugal spray granulation, the YTaO4 coatings were fabricated by atmospheric plasma spraying (APS) technique. The effect of heat treatment time and temperature on the properties of YTaO4 coatings was investigated, including phase composition, thermal conductivity, hardness and Young’s modulus. The results showing YTaO4 coating undergoes a phase change during the APS process, and has a low thermal conductivity (0.53 W·m-1·K-1 at 900 °C). As the heat treatment temperature increases, the sprayed sample undergoes the phase transition (T¢→M¢→T→M). However, the volume difference caused by the phase change is extremely small and can be ignored. Compared with YSZ, YTaO4 coating has a smaller Young's modulus, which means its tolerance is better. The results show that YTaO4 has excellent thermal-physical properties as thermal barrier coatings (TBCs).

Keywords: YTaO4 coatings, Phase change, Thermal conductivity, Elastic modulus, Thermal barrier coatings (TBCs)