Resin Impregnation Densification Preparation Of Carbon / Carbon Composites

The procedure of liquid impregnation is one of the important procedures of preparing carbon/carbon(C/C) composites. This paper prepared c/c composites by chemical vapor deposition(CVD) and liquid impregnation procedure and examined and analyzed their mechanical properties, heat conduction coefficient and friction and wear properties, and studied the relation of material procedure-structure-properties o. The result showed that the graphization degree of products was higher due to the catalysis grahization of boron of boron phenolic resin and 2Wt% boron carbide, The process of impregnation and curing should proceed successively under pressure, the stress graphization, which is closely related to cohesion of fibre and matrix precusor, appeared on the boundary of fibre and matrix ?The compressive strength and flexure strength of self-facricated composites were far above that of foreign products, the interlaminate shear strength(ILSS) was also higher o The parallel compressive strength of self-fabricated composites was 170-241MPa; parallel flexure strength was 125-201MPa; ILSS was 12-16 MPa?The flexure fracture behavior and fracture surface suggested that the effect of densifying carbon fiber preform by CVD followed by liquid impregnation was better, if we densified carbon fiber preform by liquid impregnation directly, due to too strong bonding between resin carbon which causes brittle fracture easily and carbon fibre, the resin is not appropriate to impregnate the performs at the initial process oThe heat conduction coefficient of c/c composites was closely related to their densities, graphitization degree, the higher densities, the bigger the heat conduction coefficient; the higher graphitization degree, the bigger the heat conduction coefficient o In addition, the material structure, the fibre content, the fiber type and reinforced way of fibre had also some effect on c/c composites ?The friction coefficient value was between 0.21-0.34 when ratating speed was 7500rpm, the inertia equivalent was 30kg m2, the pressure was 0.6MPa or IMPa; thebrake curves becomed stable and little fluctuant with the improvement of heat treatment temperature, the liner wear was less than 2.0 u m0 In general, with the improvement of the graphitization degree, the friction coefficient of c/c composites decreased, the brake properties curves becomed stable . In addition,the graphitization degree was also related to wear, the higher graphitization degree, the bigger mechanical wear, the less oxidized wear,,The graphization degree and heat conduction coefficient of c/c composites impregnated by boron phenolic resin were better than those of c/c composites impregnated by furan resin, but the friction and wear properties of the composites impregnated by furan resin was also better , on the mechanical properties, the compressive strength of the composites impregnated by furan resin was the highest, the toughness was better; the flexure strength of the composites impregnated by pure boron phenolic resin was the highest, the toughness was the besto...