A high-entropy (Yb0.2Y0.2Lu0.2Ho0.2Er0.2)2Si2O7 environmental barrier coating prepared by atmospheric plasma-spray

A high-entropy (Yb0.2Y0.2Lu0.2Ho0.2Er0.2)2Si2O7 coating has in the present study for the first time been prepared by using an atmospheric plasma-spray. The microstructure, composition, and properties of the coating were characterized and assessed. The phase structure of this high-entropy coating was basically the same as that of the powder. Moreover, the rare earth elements were evenly distributed (on the atomic scale) and the content was close to the theoretical value. There was no tendency for elemental segregation. This coating also showed an excellent phase stability at 1300 °C, 1400 °C, and 1500 °C, and its thermal expansion coefficient was very close to those of the ceramic matrix composites. This high-entropy coating has, thus, a high potential to be used as an environmental barrier coating, and the atmospheric plasma-spray is a suitable method to use in the preparation of these high-entropy pyrosilicate coatings.