Preparation,Mechanical And Antioxidant Properties Of C/C-SiC Composites

As a thermal structural material,C/C composite materials are generally in an aerobic service environment.C/C composite materials that have not been modified by oxidation will begin to gradually oxidize and fail at about 400?.The introduction of SiC in C/C composites to prepare carbon fiber reinforced carbon-silicon carbide(C/C-SiC)dual matrix composites not only improves the high temperature oxidation resistance of C/C composites,but also expands the application field of C/C composite materials to meet the needs of industrial applications.In this paper,the C/C-SiC composite was prepared by introducing SiC ceramic matrix into low-density C/C composite with a BN-SiC double interface layer through polymer impregnation cracking(PIP)and reactive infiltration(RMI)methods.The density,fracture mode and microstructure of C/C-SiC composites prepared by introducing SiC matrix into two methods were studied,and the performance characteristics of composites prepared by the two methods were comprehensively compared.The oxidation resistance of C/C-SiC composites was studied by high temperature static oxidation.The influence of different matrix components on the oxidation resistance of C/C-SiC composites was analyzed.The experimental results show that the C/C-SiC composites prepared by the RMI method have a dense surface and brittle fracture,but the grains of the SiC matrix are fine.C/C-SiC composites with a theoretical degree of densification close to 70% can be prepared by the PIP method.The composites show non-brittle fracture,fiber pulling out and fiber debonding phenonmenons.The density of C/C-SiC composites with different matrix components and the content of SiC ceramic matrix in the matrix will affect the mechanical properties of the composite.When the densities of the materials are similar,the mechanical properties of the composites increase with the increase of the SiC ceramic content in the matrix;the densities have a greater effect on the mechanical properties of the composites.The density and SiC content in the matrix are high,the flexural strength of the composite material can reach 227.9 MPa.Using the temperature difference of ?T=1200? for thermal quenching,it was found that the material did not have a large change in bending strength after thermal shock.The component with a higher SiC content in the material matrix showed improved mechanical properties after thermal quench.During the static oxidation at 1200?,the composite with the least SiC content in the matrix oxidized.However,at 1500?,an oxide protective layer was formed inside the composite with SiC content of 30 wt.% And 16 wt.% In the matrix,which showed good oxidation resistance.