Properties and microstructure of Cf/HfC-SiC composite prepared by combined process

The C-f/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. C-f/HfC-SiC composite has a thermal conductivity of 21.4 W center dot m(-1)center dot 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 center dot m(1/2), respectively. The compactmatrix and the toughing mechanism by fibers account for the good mechanical properties. The C-f/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.