Higher ablative resistance performance of CF-ZrO2/ZrC composites by an in-situ sol-gel method

In the present study, CF-ZrO2/ZrC composites with controllable coating thickness were prepared by an in-situ sol-gel method. Through pretreatment, the carbon fibers surface changed from hydrophobic to hydrophilic and the polar groups on the surface significantly increased, which increased the interface affinity and ensured the stabilities of uniform ZrO2/ZrC coatings preparation. The coating layer increases the thickness of the composites, prolonged the mass and heat transfer on the composites surface. The dense ZrO2/ZrC coating prevents further oxidation of internal C by oxidative gas. As a result, after 4 cycles sol-gel, the mass ablation rate of the composite is decreased from 0.046 to 0.022 mg s−1, under the butane flame for 120s. And the thermal decomposition temperatures are 10.8%–15% higher than those of the original carbon fiber. Thus, this in-situ sol-gel method is a feasible for preparing carbon fiber self-reinforced composites with uniform coating and designable structure, which can effectively improve the ablative resistance ability and thermal decomposition temperature of composites.