Mechanical Property, Oxidation and Ablation Resistance of C/C-ZrB2-ZrC-SiC Composite Fabricated by Polymer Infiltration and Pyrolysis with Preform of Cf/ZrB2

C/C-ZrB2-ZrC-SiC composites were fabricated by polymer infiltration and pyrolysis (PIP) with a preform of Cf/ZrB2. The carbon fibers and the resin carbon were coated with ceramic layer after PIP in the composites. The composite presents a pseudo-plastic fracture due to deflection of cracks and pullout of fibers. The composite has a higher bending strength by this method in comparison with the conventional PIP process due to fewer heat treatment cycles. The static oxidation test shows that the mass loss of the composites is no more than 1% after 20 min oxidation at 1100 °C. The “core-shell” structure between ZrC-SiC ceramic and other phases plays a positive role in preventing the inward diffusion of oxygen. The ablation resistance of the C/C-ZrB2-ZrC-SiC composite samples was tested using a plasma generator. After ablation for 120 s, the mass and linear ablation rates of the composites are 4.65 mg cm−2 s−1 and 2.46 µm s−1, respectively. The short carbon layer shows a better ablation resistance than the nonwoven carbon fabric layer after the ceramic coating is peeled off because of its higher ceramic content.