1. School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
2. National Key Laboratory of Science and Technology on Materials Under Shock and Impact,Beijing Institute of Technology， Beijing 100081, China
et al.
SiCf/SiC ceramic matrix composites meet the high thrust-to-weight ratio requirements of next-generation aeroengines but require environmental barrier coatings for protection under extreme high-temperature conditions. Current environmental barrier coatings inevitably develop cracks during service,necessitating self-healing coatings for autonomous crack repair. In this study, based on Yb2Si2O7,Yb2Si2O7-SiC and Yb2Si2O7-Yb2SiO5 were fabricated via spark plasma sintering and pressureless sintering, respectively. The self-healing behavior of these composites was investigated to evaluate their feasibility as environmental barrier coating materials.Results show that adding 5wt%~10wt% SiC to Yb2Si2O7 promoted crack healing after 1 h at 1100 ℃ in air, driven by SiO2 formation from SiC oxidation, which filled cracks through volume expansion. However, at 1300 ℃, excessive SiC oxidation caused significant volumetric stress, generating new cracks within the composites. Yb2SiO5 addition enhanced material densification and crack healing. The composite with 50wt% Yb2SiO5 achieved optimal healing efficiency (78%), attributed to thermally induced compressive stress from higher thermal expansion coefficient of Yb2SiO5. This stress facilitated crack closure in the Yb2Si2O7 matrix.