Microstructure and ablation behavior of double anti-oxidation protection for carbon-bonded carbon fiber composites

To improve the oxidation protective ability of carbon-bonded carbon fiber (CBCF) composites, double anti oxidation protection for CBCF composites were prepared, i.e., ceramic coating-coated CBCF composites combined with ceramic-modified carbon fiber in CBCF matrix. The ablation behavior of modified CBCF composites was tested under an oxyacetylene flame at 1600 degrees C for 300 s and 800 s, respectively. The results indicate that the ZrB2 in matrix and ZrB2-based ceramic coating can play double protection for CBCF composites during ablation process. The linear ablation rate of the sample after ablation for 300 s and 800 s were -1.1x10(-4) and 8.38x10(-4) cm s(-1), respectively. The modified CBCF composites presented excellent oxidation resistance for 300 s. With the increase of the oxidation time for 800 s, the ZrB2-based ceramic coating experienced catastrophic damage. However, the carbon fiber surface only exhibited some circular pits instead of complete oxidation, implying that the ZrB2 on the carbon fiber surface improved the anti-oxidation and ablation resistance of CBCF composites.