Long-term oxidation behaviors of C/SiC composites with a SiC/UHTC/SiC three-layer coating in a wide temperature range

A SiC/UHTC/SiC triple layer was designed and coated on C/SiC composites by chemical vapor deposition and brushing-sintering techniques to achieve long-term oxidation protection in a wide temperature range. After exposure to 1100 °C and 1300 °C for 114 h, and 1500 °C for 68 h in air, the coated composites exhibited mass losses of only 0.36, 1.65 and 3.45 mg/cm2, respectively. The low mass loss rates can be attributed to the synergistic effects of the ZrB2-based ultra-high temperature ceramic (UHTC) and SiC layers. The oxidation process and protective mechanism at different temperatures were discussed in detail.