Influence of solvothermal treatment time on oxidation of carbon/carbon composites containing ZrB2 micro-particles

Abstract

Carbon/carbon composites were modified with a borate sol precursor and ZrB2 micro-particles by a sol–gel/solvothermal method to improve the oxidation resistance property at low temperature. The phase compositions, surface and cross-section microstructures of the C/C matrix were investigated. Results show that the surface of the composites is covered by a B2O3 and ZrB2 layer. The internal micro-holes are occupied by B2O3 and ZrB2. The anti-oxidation property of the composites after modification improves with the increase of the solvothermal treatment time from 24h to 60h. Longer solvothermal treatment time is found to have more ZrB2 both on the surface and inside the matrix, resulting in better anti-oxidation property. The carbon/carbon composites modified at 453K for 60h exhibit the best anti-oxidation property, which can effectively protect carbon/carbon composites from oxidation in air at 1073K for 12h with a mass loss of 0.1%. The formation of B2O3 and ZrO2 is found to be helpful to improve the oxidation resistance of the composites. The oxidation of the modified C/C composites was particularly studied.