Properties and microstructure of C_f/HfC‐SiC composite prepared by combined process

Abstract

The Cf/HfC‐SiC composite was produced by precursor infiltration and pyrolysis combined with gaseous silicon infiltration and an open porosity as low as 5.4% was achieved. Cf/HfC‐SiC composite has a thermal conductivity of 21.4 W·m−1·K−1, in addition, its flexural strength, elastic modulus, and fracture toughness are 328.9 ± 58.4 MPa, 48.9 ± 2.8 GPa, and 10.2 ± 1.2 MPa·m1/2, respectively. The compact matrix and the toughing mechanism by fibers account for the good mechanical properties. The Cf/HfC‐SiC composite survives the oxyacetylene torch test and the formation of a protective oxide scale by joint action of SiO2 and HfO2 contributes to good ablation performance of the composite.