Effects of Y2O3 coating on the mechanical properties of SiO2f/SiO2 composites after long-term heat treatment

The Y 2 O 3 coating was prepared on the quartz fibers via the precursor conversion method. Subsequently, quartz fiber-reinforced SiO 2 matrix (SiO 2f /SiO 2 ) composites were prepared using the slurry impregnation method. The effects of the thickness of Y 2 O 3 coating on the mechanical properties of the SiO 2f /SiO 2 composites were investigated. The results indicated that the SiO 2f /SiO 2 composites with a 0.10 μm Y 2 O 3 coating exhibited the optimal comprehensive mechanical properties, possessing a compressive strength, flexural strength, fracture strain, and fracture toughness of 49.0 MPa, 23.6 MPa, 4.44%, and 0.72 MPa m 1/2 , respectively. After heat treatment at 900 °C for 40 h, the flexural strength, fracture strain and fracture toughness of the SiO 2f /SiO 2 composites with a 0.10 μm Y 2 O 3 coating were 20.3 MPa, 4.27% and 0.60 MPa m 1/2 , respectively, representing increases of 12.8%, 94.1% and 13.2% compared to the composites without the Y 2 O 3 coating. The Y 2 O 3 coating improves the interfacial bond strength of the SiO 2f /SiO 2 composites after long-term heat treatment, promoting crack deflection at the interface and thereby enhancing the mechanical properties of the SiO 2f /SiO 2 composites.