The thermal and environmental barrier coatings (T/EBC) are technologically important for advanced propulsion engine system. In this study, RE4Hf3Oi2 (RE=Ho, Er, Tm) with defect fluorite structure was investigated for ...The thermal and environmental barrier coatings (T/EBC) are technologically important for advanced propulsion engine system. In this study, RE4Hf3Oi2 (RE=Ho, Er, Tm) with defect fluorite structure was investigated for potential use as top TBC layer. Dense pellets were fabricated via a hot pressing method and the mechanical and thermal properties were characterized. RE4Hf3Oi2 (RE=Ho, Er, Tm) possessed a high Vickers hardness of 11 GFa. The material retained high elastic modulus at elevated temperatures up to 1773 K, which made it attractive for high temperature application. The coefficient of thermal expansion (CTE) of RE4Hf3Oi2 (RE = Ho, Er, Tm) laid in the range between 7× 10^-6K^-1 to 10×10^16K^-1 from 473 K to 1673 K. In addition, the rare earth hafnates exhibited lower thermal conductivity which rendered it a good candidate material for thermal barrier applications.展开更多
基金supported financially by the National Key R&D Program of China (No. 2017YFB0703201)the National Natural Science Foundation of China (Nos. 51402311, 51372252 and 51772302)the International Cooperation Key Program (No. 174321KYSB20180008)
文摘The thermal and environmental barrier coatings (T/EBC) are technologically important for advanced propulsion engine system. In this study, RE4Hf3Oi2 (RE=Ho, Er, Tm) with defect fluorite structure was investigated for potential use as top TBC layer. Dense pellets were fabricated via a hot pressing method and the mechanical and thermal properties were characterized. RE4Hf3Oi2 (RE=Ho, Er, Tm) possessed a high Vickers hardness of 11 GFa. The material retained high elastic modulus at elevated temperatures up to 1773 K, which made it attractive for high temperature application. The coefficient of thermal expansion (CTE) of RE4Hf3Oi2 (RE = Ho, Er, Tm) laid in the range between 7× 10^-6K^-1 to 10×10^16K^-1 from 473 K to 1673 K. In addition, the rare earth hafnates exhibited lower thermal conductivity which rendered it a good candidate material for thermal barrier applications.
