中间相沥青改性可陶瓷化硅橡胶复合材料性能及烧蚀层微观分析OA

The ceramifiable silicone rubber was prepared by blending with silicone rubber as the matrix,molyb-denum silicide(MoSi2)as ablation-resistant filler,a glassy material as low melting point filler,and mesophase pitch(MP)as ceramisation-assisting reactive substance.The tensile strength of the composites at room temperature,the flexural strength of the composites after high-temperature heat treatments at 600℃,800℃,1 000℃,and 1 200℃,and the microscopic morphology and phase evolution of the ablated centre region after oxygen-acetylene flame ablation were tested.The effects of MP content on the mechanical properties,high-temperature oxidation resistance and abla-tion resistance of the ceramicisable silicone rubber composites were investigated.The results showed that the flexural strength of the pyrolysis product of the composite with 20 parts of MP added reached 9.54 MPa after heat treatment at 1 200℃,which was 55.9%higher than that of the composite without MP added.The microscopic morphology shows that the addition of MP can effectively improve the densification of the carbon layer,and the surface of the composite material gradually becomes flat with the increase of MP content,and cracks and holes are basically not observed on the surface.