添加树脂碳对针刺 C / C-SiC 材料熔渗行为及性能的影响

Two kinds of carbon substrates(pyrolytic carbon or pyrolytic carbon with resin carbon)with density of 1.35 g/ cm³ were prepared by chemical vapor infiltration and resin impregnation pyrolysis using 2.5D non-woven carbon cloth and carbon felt laminated needle-punched preform as the structure reinforcement,afterwards,C/ C-SiC composites were obtained by means of the reaction melt infiltration(RMI)method, and influence of different carbon substrates on infiltrated characteristics,microstructure, tensile properties and oxyacetylene ablation properties of C/ C materials were analyzed.The results show that compared with“thin-wall” porous structure formed in pyrolytic carbon strengthed C/ C composites,the“slit”porous structure formed in resin carbon strengthed C/ C composites is beneficial for enlarging the contact area between liquid Si and carbon matrix,improving the infiltration kinetics of RMI process,and obtaining the C/ C-SiC composites with high density and SiC content.The C/ C-SiC composites with resin carbons shows excellent anti-ablation property, and linear ablation rate of the C/ C-SiC composites ablated in oxyacetylene environement for 400 to 600 seconds is reduced by 24%.However the infiltration to liquid Si induced by resin carbon increases the damage for C/ C bone structures,which makes the tensile strength of resin carbon+pyrolytic carbon-based C/ C-SiC composites(104 ± 3)MPa lower than that of pyrolytic carbon-based C/ C-SiC composites(118 ± 3)MPa at room temperature.