Research progress in rare earth silicate environmental barrier coatings

Ceramic matrix composites are desirable materials for the hot end components of high performance generation aeroengines due to their high temperature resistance, low density and excellent high temperature mechanical properties. However, when exposed to combustion environment, the ceramic matrix composites are subjected to serious water vapor corrosion. Thus, environmental barrier coatings are indispensable to apply to their surfaces to extend their service life.The rare earth silicate has become the primary candidate material for the new generation of environmental barrier coating materials because of its suitable thermal expansion coefficient with the substrate, outstanding water vapor corrosion resistance and high temperature stability. The characteristics, preparation techniques and typical service performance of rare earth silicates were reviewed in this paper, with focus on their classification, thermal/physical properties, as well as the damage and failure mechanisms during high-temperature corrosion processes. Finally, the research directions of high entropy design of multi-component rare-earth silicates and the design of new thermal/environmental barrier coating systems were proposed. This paper aims to provide useful references for the further application of rare earth silicate materials.