Interaction of high-entropy rare-earth monosilicate environmental barrier coatings subjected to corrosion by calcium-magnesium-alumino-silicate melts

The high-entropy design of rare-earth silicates has been expected to improve CMAS corrosion resistance, which is essential to the development of EBCs for aero-engines. In this work, CMAS corrosion behaviors of plasma-sprayed high-entropy monoslicates ((Lu0.25Yb0.25Er0.25Y0.25)2SiO5 and (Lu0.2Yb0.2Er0.2Ho0.2Y0.2)2SiO5) and Y2SiO5 coatings at 1350 °C for 25–50 h were investigated and compared. The corrosion products included apatite and garnet based on the dissolution-reprecipitation mechanism. The high-entropy coatings possessed improved corrosion resistance compared with the Y2SiO5 coating, which was mainly due to the doped RE elements with smaller ionic radius could improve the stability of crystal structure and form garnet phase more easily.