Rare earth silicate in SiC f /SiC composites: Toward water‒oxygen corrosion resistance in high‐temperature gas environment

Silicon carbide fiber‐reinforced silicon carbide ceramic matrix (SiC f /SiC) composites are considered as one of the preferred materials for aero‐engine hot‐end components; however, they will face serious performance degradation when exposed to the complex and harsh environment of high temperature and water‒oxygen corrosion coupling. How to solve the problem of SiC f /SiC composites is a growing concern in the international community. Rare earth silicate materials usually have the advantages of good high‐temperature stability, low oxygen permeability constant, and thermal expansion coefficient matching with SiC, which are internationally recognized as the preferred systems for the new generation of environmental barrier coatings (EBCs); meanwhile, the use of rare earth compounds for matrix modification of SiC f /SiC composites to improve their resistance to water‒oxygen corrosion has gained wide attention. Therefore, the recent progress in rare earth silicate EBCs and modified SiC f /SiC composites are reviewed. Finally, the challenges and prospects of rare earth silicate in improving the water‒oxygen corrosion resistance of SiC f /SiC composites are presented.