Preparation of compact ZrC-SiC ceramic matrix from thermoset precursors for C/C-ZrC-SiC composites with high mechanical properties

C/C-ZrC-SiC composites with compact ceramic matrix were prepared by thermoset precursors with abundant active functional groups through precursor infiltration and pyrolysis. The mechanism of cross-linking and ceramization of precursor, and the effect of precursor structure on ceramic matrix, interface and mechanical properties of C/C-ZrC-SiC composites were studied. The compact structure of ZrC-SiC ceramics was ascribed to close cross-linked structure, and directly crystallized SiC without carbothermal reduction. The pyrolyzed precursor with more compact structure generated denser ceramic matrix and better interface bonding between the ceramic matrix and the carbon matrix. The composites with compact ZrC-SiC matrix and slightly defective interface performed ideal non-brittle fracture pattern, the flexural and compressive strength were 239 +/- 21 MPa and 302 +/- 24 MPa. The high mechanical properties could be ascribed to the considerable elastic modulus of ZrCSiC matrix, and the apparent crack deflection and fiber pull-out caused by the moderate thermal residual stress damage and interface bonding.