3D Cf/SiBCN composites prepared by an improved polymer infiltration and pyrolysis

摘要

Using liquid poly（methylvinyl）borosilazanes （PMVBSZ） as precursor, carbon fiberreinforced SiBCN matrix composites （Cf/SiBCN） were fabricated by a modified polymer infiltrationand pyrolysis （PIP） process. With dicumyl peroxide added as cross-linking agent, the PMVBSZ couldbe solidified at a low temperature of 120℃, leading to a high ceramic yield of-70%. Thecross-linking mechanism and ceramization processes of the precursor were investigated in detail.Moreover, a modified infiltration technology was developed, which improved the efficiency andprotected the precursor against moist air during PIP. Consequently, the obtained Cf/SiBCN compositeshad an oxygen content of around 1.22 wt%. Benefiting from the high ceramic yield and highefficiency of the modified PIP, Cf/SiBCN composites with an open porosity of -10% and uniformmicrostructure were obtained after only 7 cycles of PIP. The flexural strength and fracture toughnessof the derived Cf/SiBCN composites were 371 MPa and 12.9 MPa.m1/2, respectively. This workprovides a ootential route for the fabrication of hida performance Cf/SiBCN composites.