Microstructure and ablation behavior of C/C composites doped with ZrB₂

ZrB₂ was first introduced into carbon preforms through ultrasonic and vacuum immersion-carbonthermal reduction method. After densification using thermal gradient chemical vapor infiltration and graphitization, ZrB₂ doped C/C composites were prepared. The oxyacetylene ablation results show that the linear and mass ablation rates of the composites after doping with 6.87wt% ZrB₂ decreased by 64.9% and 67.5%, respectively. The ablation of C/C composites is mainly controlled by thermochemical and thermophysical reactions and mechanical denudation does not play a dominant role. The evaporation of ZrO₂/B₂O₃ during ablation would take away large amounts of heat, reducing the thermal impact of flame to the ablation surface.