Pressureless Preparation and Properties of C/SiC Composites

Polycarbosilane was used as the preceramic for matrix formation and 2D layered 0°/90°C fabrics as the reinforcement to fabricate C/SiC composites.The effect of pyrolysis temperature and slurry concentration on the properties of the composites was systematically studied.The results show that the flexural stress increase with the increase of both pyrolysis temperature and slurry concentration. The matrix distribution in fiber bundle is quite homogeneous,but some small pores still exist after eight pyrolysis cycles.When the composite is pyrolyzed at 1100℃,β-SiC begins to form in the matrix. The flexural stress and toughness reach 232MPa and 10.50MPa.m~(1/2),respectively.Observation of long pull-out fibers in the fracture surface demonstrates a toughened fracture behavior of the composite.