Effects of porous C/C density on the densification behavior and ablation property of C/C–ZrC–SiC composites

Abstract

C/C–ZrC–SiC composites were prepared by precursor infiltration and pyrolysis process using a mixture solution of organic zirconium-containing polymer and polycarbosilane as precursors. Porous carbon/carbon (C/C) composites with density of 0.92, 1.21 and 1.40g/cm3 were used as preforms, and the effects of porous C/C density on the densification behavior and ablation resistance of C/C–ZrC–SiC composites were investigated. The results show that the C/C preforms with a lower density have a faster weight gain, and the obtained C/C–ZrC–SiC composites own higher bulk density and open porosity. The composites fabricated from the C/C preforms with a density of 1.21g/cm3 exhibit better ablation resistance with a surface temperature of over 2400°C during ablation. After ablation for 120s, the linear and mass ablation rates of the composites are as low as 1.02×10−3mm/s and −4.01×10−4g/s, respectively, and the formation of a dense and continuous coating of molten ZrO2 solid solution is the reason for their great ablation resistance.