Effect of Pyrolytic Carbon Coating on Properties of C_f/C-SiC-ZrC Ceramic Matrix Composites

In this paper, C_f-SiC-ZrC, C_f/C-SiC-ZrC composites which the pyrolytic carbon (PyC) coating with the thickness of 0.1 μm, 0.3 μm and 0.5 μm were prepared by chemical vapor deposition (CVD) process combined with precursor infiltration and pyrolysis (PIP) process. Then, SEM, XRD and other methods were used to test the microstructure, flexural strength, fracture toughness and static oxidation of the composites. The results show that after the CVD process, PyC with higher degree of graphitization is deposited on the carbon fiber surface, which can avoid damage to the carbon fiber caused by the PIP process for preparing the ceramic matrix composite. The mechanical properties and oxidation resistance of C_f/C-SiCZrC ceramic matrix composites are higher than C_f-SiC-ZrC composites, and the flexural strength reached 283 MPa, the fracture toughness reached 4.40 MPa•m^1/2. After oxidation for 30 min at 1400°C, we found that the composite with PyC coating of 0.3 μm had good oxidation resistance. (paper)