Preparation and properties of C/C-ZrC-SiC-ZrB₂ composites via polymer infiltration and pyrolysis

C/C-ZrC-SiC-ZrB₂ composites were prepared by precursor infiltration and pyrolysis (PIP) process using a mixture solution of organic ZrC, ZrB₂ precursor and polycarbosilane as precursor. Microstructure, flexural property and ablation behavior of the composites were studied. The results show that the composites produced by PIP have a homogeneity distribution of ceramic phase. The flexural strength of the composites is 126.31 MPa. There are a large number of carbon fiber bundles pulled-out, and the composites exhibit a pseudo-plastic fracture behavior. After ablated for 120 s by oxyacetylene flame, the composites show no significant ablation, and their linear and mass ablation rates are -2.50×10^-4 mm/s and -1.33×10^-4 g/s, respectively. Different kinds of protective coatings form on the different regions of ablated surface, which can not only reduce the diffusion of oxygen and heat but also remedy defects effectively, and thereby greatly improves the ablation resistance of the composites.