As candidate thermal/environmental barrier coatings(T/EBCs),the structure characteristics and comprehensive properties of monoclinic-prime(m')RETaO4(RE=Yb,Lu,Sc)with excellent Al2O3/SiO2 chemical compatibility are...As candidate thermal/environmental barrier coatings(T/EBCs),the structure characteristics and comprehensive properties of monoclinic-prime(m')RETaO4(RE=Yb,Lu,Sc)with excellent Al2O3/SiO2 chemical compatibility are studied.Excellent thermal insulation protection will be provided by m'RETaO4 due to their low thermal conductivity(~1.6 Wm^-1 K^-1,900℃)and prominent thermal radiation resistance,which is much better than those of YSZ(~2.5 Wm^-1 K^-1,1000℃)and La-12 Zr2O7(~2.0 Wm^-1 K,900℃).The thermal expansion coefficients(TECs)are 3.0–8.0×10^-6 K^-1(200-1200℃),which is suitable for T/EBCs applications.Furthermore,absence of phase transition and extraordinary chemical compatibility with Al2O3/SiO2 up to 1500℃indicate the potential application prospect.The documented governing mechanisms of m'RETaO4 properties will enable researchers to promote their application in the future investigation.展开更多
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under the support of the Natural Science Foundation of China(No.51762028,No.91960103)Materials Genome Engineering of Rare and Precious Metal of Yunnan Province(No.2018ZE019)。
文摘As candidate thermal/environmental barrier coatings(T/EBCs),the structure characteristics and comprehensive properties of monoclinic-prime(m')RETaO4(RE=Yb,Lu,Sc)with excellent Al2O3/SiO2 chemical compatibility are studied.Excellent thermal insulation protection will be provided by m'RETaO4 due to their low thermal conductivity(~1.6 Wm^-1 K^-1,900℃)and prominent thermal radiation resistance,which is much better than those of YSZ(~2.5 Wm^-1 K^-1,1000℃)and La-12 Zr2O7(~2.0 Wm^-1 K,900℃).The thermal expansion coefficients(TECs)are 3.0–8.0×10^-6 K^-1(200-1200℃),which is suitable for T/EBCs applications.Furthermore,absence of phase transition and extraordinary chemical compatibility with Al2O3/SiO2 up to 1500℃indicate the potential application prospect.The documented governing mechanisms of m'RETaO4 properties will enable researchers to promote their application in the future investigation.
基金This work was 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.