Oxygen barrier behavior and mechanism of Zr-Si-B-O biomimetic glass film for ZrB2-SiC coating

To reduce the oxidation damage during the initial active oxidation stage of ZrB 2 -SiC coating, this paper employed a slurry-brushing method to prepare a self-healing Zr-Si-B-O biomimetic glass film on the surface of the ZrB 2 -SiC coating. Furthermore, the oxidation resistance behavior of biomimetic glass films with varying ZrO 2 contents was investigated. Experimental results indicate that the Zr-Si-B-O biomimetic glass film can significantly reduce the oxidation weight gain of ZrB 2 -SiC coating. The biomimetic glass film sample with 70 wt% ZrO 2 exhibits the best oxidation protection effect. After oxidation treatment in the temperature range of 600-1600 °C, the weight gain is only 0.081 × 10 −2  g cm −2 , which is 95.35% lower than that of the sample without the biomimetic glass film; after oxidation at 1700 °C, the final protection efficiency and average carbon loss rate reach the optimal values of 99.97% and 0.34 × 10 −6  g cm −2  s −1 , respectively, and the average oxygen permeability is only 0.35%. The presence of Zr-Si-B-O biomimetic glass film can significantly reduce the oxidation activity and improve the oxidation resistance of the coating. This is attributed to the pre-introduction of a flowable and self-healing glass on the coating surface, which prevented the intense oxidation of the coating at the initial stage.