Investigation on behavior and mechanism of enhanced water vapor corrosion resistance for (Lu0.25Yb0.25Er0.25Y0.25)2SiO5 environmental barrier coating

Abstract

Rare-earth monosilicate (RE2SiO5) have been considered to be a promising material for the environmental barrier coating because of their superior thermal and mechanical properties. However, the water vapor corrosion resistance of single-component RE-silicate materials, such as Y2SiO5, should be further improved. The high-entropy design is one of the most suitable methods to enhance the corrosion resistance for single-component RE-silicate materials. In this work, the multicomponent RE-silicate ((Lu0.25Yb0.25Er0.25Y0.25)2SiO5, (4HES)) and single-component RE-silicate (Y2SiO5) coatings were investigated with regard to its water vapor corrosion behaviors at 1350 °C for 300 h. A thinner and denser corrosion layer was generated in the 4HES coating, indicating that the 4HES coating possessed better corrosion resistance than the Y2SiO5 coating. The improved corrosion resistance is attributed to the better hydrophobic property as well as the more stable crystal structure of the rare-earth oxide and 4HES phase which was resulted from the high-entropy design.