Fabrication and properties of PIP 3D Cf/ZrC–SiC composites

Three-dimensional (3D) Cf/ZrC–SiC composites were successfully prepared by the polymer infiltration and pyrolysis (PIP) process using polycarbosilane (PCS) and a novel ZrC precursor. The Cf/ZrC–SiC composite with relatively more PIP cycles of PCS has a higher density and a lower porosity, which account for the improved mechanical property of the composite. The composite with 6 PIP cycles of PCS has a flexural strength of 136.0±13.1 MPa, and a fracture toughness of 7.3±0.3 MPa m1/2, which is superior to the monolithic ultrahigh temperature ceramics. The relatively low flexural strength and elastic modulus of the Cf/ZrC–SiC composites are attributed to the small stiffness of the matrix because of the debonding feature of the ZrC matrix. The high temperature oxidation testing of the S6-Cf/ZrC-SiC composite reveals that the surface molten ZrO2 layer contributes mainly to the improved anti-ablation property.