Fabrication and characterization of C/SiC composites with large thickness, high density and near-stoichiometric matrix by heaterless chemical vapor infiltration

The C/SiC composites with a 7-8 mm thickness, a 2.3-2.4 g/cm3 density, and a Si/C ratio 1.08-1.09 matrix have been fabricated by heaterless chemical vapor infiltration (CVI) in a 25-h deposition time. The C/SiC composites exhibited a damage-tolerant fracture behavior, and its average flexural strength, longitudinal/transverse compressive strength and fracture toughness were 163 MPa, 304/276 MPa and 6.5 MPa m1/2, respectively. The composites presented a thermal expansion of (1.09-1.93) × 10−6 °C−1 and a thermal conductivity (TC) of 8.34-6.56 W/m °C in the range 200-1000 °C.