Fabrication and properties of lightweight ZrB₂ and SiC-modified carbon bonded carbon fiber composites via polymeric precursor infiltration and pyrolysis

To improve the oxidation-resistance of carbon bonded carbon fiber composites (CBCFs), the low density and porous CBCFs modified with ZrB₂ and SiC ceramics with a density of 0.26, 0.40, 0.61 and 0.77 g cm^-3 were prepared by precursor infiltration and a pyrolysis method. The pyrolysis behavior of the Zr and B-containing hybrid polymeric precursor was studied. The densification behaviour was investigated through the analysis of the microstructures of CBCFs-SiC-ZrB₂ (denoted as CSZ) composites with different density. The mechanical properties, thermal properties and oxidation behavior of the CSZ composites were studied. The results show that the incorporation of a ZrB₂ ceramic coating does not change the anisotropic properties of the CBCF composites. The CSZ composites with a density of 0.77 g cm^-3 with a continuous ZrB₂ ceramic coated layer on the surface of the carbon fibers which exhibit better mechanical properties and antioxidant properties. The composites show remarkable thermal properties which are good for thermal insulation applications.