Oxidation behaviors of yttrium silicate modified SiC_f/SiC composites in air and water-oxygen environments

SiC_f/SiC composites have emerged as one of the most promising materials for aero-engine hot-end structures. However, their performance is limited by their susceptibility to oxidation and corrosion reactions with oxygen and water vapor. To overcome this challenge, antioxidant-modified phases are introduced into matrices of SiC_f/SiC composites which improve their water and oxygen resistance. In this study, the resistance of SiC_f/SiC composites modified by yttrium silicate matrix (SiC_f/SiC-YS composites) to air at 1000–1400°C and water-oxygen environments at 1200°C was investigated. The diffusion paths of oxygen in SiC_f/SiC-YS composites and the antioxidant behavior of the yttrium silicate matrix were discussed. Additionally, the differences in oxygen and water-oxygen corrosion resistance of SiC_f/SiC-YS composites at the same temperature were compared. The strength retention of SiC_f/SiC-YS composites after oxidation and water-oxygen corrosion at 1200°C were 138.6% and 108.8%, respectively. This indicates that the addition of water vapor accelerated the degradation of SiC_f/SiC-YS composites. By comparing with SiC_f/SiC composites, it can be concluded that the modification of the yttrium silicate matrix considerably improved the oxidation resistance of SiC_f/SiC composites.