Oxidation Behavior and Mechanical Property of Ceramifiable Phenolic Resin Matrix Composites with a Wide Temperature Range

The surface of MoSi 2 -SiB 6 / phenolic resin matrix composites was modified by mica, and the thermal oxidation behavior of the composites and the mechanical properties of the pyrolysis products were studied. The results showed that the mica improved the thermal properties of the composites, the thermal expansion coefficient decreased, and the liquid phase formation caused the composites to shrink and increase the density. The flexural strength of mica surface modified composites not only increased to 78.64 MPa after thermal treatment at 800–1 200 °C, but reached 83.02 MPa after high temperature treatment at 1 400 °C. The improvement of the mechanical properties of the residual product benefits from the formation of high temperature ceramic phases such as Mo 2 C and MoB, and the improvement of the shear strength of the composites by the mica. The shear strength of MBm5-2 at room temperature reached 33.08 MPa, indicating that the improvement of the interlayer properties of the composites further improved its mechanical properties.