The impact of water and oxygen contents on the corrosion performance of yttrium silicate modified SiCf/SiC composites under high temperature conditions

SiCf/SiC composites have emerged as a prominent research area in the field of structural materials for engine hot end applications. However, SiCf/SiC composites exhibit susceptibility to oxidation and corrosion when exposed to oxygen and water vapor. The yttrium silicate ceramic in the SiCf/SiC composite (SiCf/SiC-YS composite) serves as corrosion-resistant matrix. The corrosion behavior of SiCf/SiC-YS composites was assessed by examining the phase composition, microstructure, and bending strength after exposure to different water and oxygen environments. The results show that SiCf/SiC-YS composites exhibit excellent resistance to water and oxygen at temperatures below 1300 degrees C. Above 1300 degrees C, the decomposition of yttrium disilicate affects the internal structure and bending strength of the composites. Temperature-and water vapor concentration-dependent crystal transformation of yttrium silicate is a crucial factor that influences the microstructure and water oxygen corrosion resistance of SiCf/SiC-YS composites.