Fabrication and properties of 2D C/C-ZrB2-ZrC-SiC composites by hybrid precursor infiltration and pyrolysis

Two dimensional C/C-ZrB2-ZrC-SiC composites were fabricated through precursor infiltration and pyrolysis process using a mixture of polycarbosilane and ZrB2 precursor and ZrC precursor as the impregnant. The microstructures, mechanical properties and ablation properties of the composites were investigated. The results showed that the homogeneity of the composite improved on using novel precursors that can dissolve with polycarbosilane through the formation of nanocomposite matrix. The flexural strength and fracture toughness first increased and then decreased on increasing the pyrocarbon content in the composite. Compared with the C/C-SiC composite, the ablation resistance of C/C-ZrB2-ZrC-SiC composite was greatly enhanced. The mass loss rate and linear recession rate exposed to the plasma torch were 1.7 mg/s and 1.8 mu m/s, respectively. The formation of a ZrO2-SiO2 glassy layer on the surface significantly contributed to the excellent ablative property of the composite.