Effect of ZrO₂ from the oxidation of ZrC on ablation of ZrC modified carbon/carbon composites

Zirconium-containing carbon fiber preform was prepared by ZrOCl₂ aqueous solution impregnation. ZrC modified carbon/carbon (C/C) composites were obtained by a series of procedures combined with densification by thermal gradient chemical vapor infiltration (TCVI) and high-temperature graphitization. The ablation properties were tested in an oxyacetylene torch. The phase composition and morphology of the composites were investigated by XRD and SEM, respectively. Results show that, with increasing ablation times, the linear and mass ablation rates increase firstly and then decrease, remain constant finally when ZrO₂ is not removed after each ablation. Meanwhile, the linear and mass ablation rates increase with the ablation time in case of removing ZrO₂ after each ablation. The evaporation of ZrO₂ will absorb heat and relieve erosion from oxyacetylene flame on the ablated surface of the specimen, and also accelerate the mass loss of the specimen, which leads to the decrease of the linear ablation rate and increase of mass ablation rate of the composites.