Solution based processing and properties of carbon fiber reinforced SiCÂ +Â ZrO2 composites

Uni-directional carbon fiber (Cf) reinforced SiC + ZrO2 composites were prepared by a solution approach in which the matrix was prepared using water-soluble precursors of colloidal silica, sucrose and zirconium oxychloride as sources of silica, carbon and zirconia respectively. After suitable heat treatment, the precursors convert into fine SiC + ZrO2 particles with a uniform dispersion. In Cf/SiC + ZrO2 composites, in situ formation of SiC + ZrO2 provides an effective way for uniform dispersion of SiC and ZrO2 in the matrix. Analysis indicates complete reaction of the precursors to yield SiC + ZrO2 as the composite matrix. The room temperature mechanical properties and the fracture behaviour of the composites were examined. A tensile strength of 617 ± 54 MPa and fracture energy of 2.69 ± 0.9 MJ/m3 were obtained. The tensile strength of Cf/SiC + ZrO2 composites was twice that of Cf/SiC composites produced by same approach. This is attributed to stabilization of the zirconia phase in the presence of the SiC phase by tailoring the starting materials and their composition.