Microstructure and Ablation Behavior of C/C Composites Doped with ZrB_2

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 com-posites 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.