A low-temperature preparation strategy of SiC/ZrB2-CrSi2-Si/SiC multilayer oxidation-resistant coating for C/C composites: Process, kinetics and mechanism research

[Display omitted] •The self-healing SCZ layer was prepared at low temperature by pre-oxidation.•The effects of the synthesis on the microstructure and performance was discussed.•It is proved that SiCxOy is crucial to the coating protection/failure mechanism.•The protection/failure mechanisms at different temperatures was clarified. In this work, a strategy of preparing multilayer SiC/ZrB2-CrSi2-Si/SiC coating at low-temperature by combining chemical vapor deposition (CVD), brush-sintering and preoxidation was proposed for C/C composites. The coated C/C composites could maintain stable and long-term oxidation resistance at 1473–1673 K, and the specific mass loss was only 8.05 mg∙cm−2 after 1673 K/340 h oxidation. The coupling mechanism of the preparation process on the microstructure and performance, the kinetics process of oxidation behavior and the protection/failure mechanism of the coating were analyzed. Furthermore, the importance of organosilicon (SiCxOy) in the process of self-healing and oxidation resistance was enlightened.