Study On Preparation And Properties Of C_f/C-SiC Composites Modified By Graphene Materials

Compared with traditional materials,C_f/C-SiC composites inherit the good mechanical properties of carbon fiber and the high temperature oxidation resistance of silicon carbide substrates,and are widely used in aerospace and other industrial fields.With the development of aerospace vehicles,the aerospace industry has placed higher demands on the high temperature and mechanical properties of carbon fiber reinforced ceramic matrix composites in extremely harsh environments.However,in the process of preparing C_f/C and C_f/C-SiC composites The medium matrix is prone to cracks,making it difficult for composite materials to meet higher performance requirements.In this paper,hydrothermal reduction method is used to introduce nano-scale graphene into C_f/C-SiC composites to improve the structure of the matrix,make the matrix of the composite more dense,reduce the defects such as cracks,and improve the bending properties and resistance of the composite.Oxidation properties.The effects of graphene content on C_f/C-SiC composite silicon carbide,pyrolytic carbon microstructure,bending properties and oxidation resistance were studied.The main conclusions are as follows:(1)As the content of graphene materials increases,the graphene material in the preform has a tendency to assemble into a network structure,and when the content of the graphene material in the preform increases to 1.2 wt%,Graphene materials achieve a variety of bonding methods inside the carbon fiber.(2)Due to the presence of graphene material,the grain of silicon carbide is refined and ordered,and the dense deposition of pyrolytic carbon makes the pyrolysis carbon structure more complete and the degree of graphitization higher.(3)When the content of graphene in the preform reaches 1.2wt%,the graphene material and the carbon fiber appear in various overlapping manners,so that the bonding between the carbon fibers becomes stronger,and the interface between the carbon fiber and the matrix is??optimized,and the ceramic is improved.The bending properties of the base composite.As the content of graphene material increases,the flexural strength and modulus of rGO-Cf/C-SiC composites increase first,and the maximum load and fracture strength of composites increase with graphene.Increase.(4)Compared to the pure Cf/C-SiC composite,the rGO-Cf/C-SiC composite exhibited a lower oxidation rate in the isothermal oxidation performance test at600-900°C.When the graphene content in the preform is 0.8wt%,the rGO-Cf/C-SiC composite has the best oxidation resistance.When the graphene content is too much,the graphene material on the surface of the preform is excessively stacked,and the pyrolytic carbon is unevenly deposited.The surface of the rGO-Cf/C-SiC composite is prone to microporosity,thereby deteriorating the oxidation resistance of the composite.