Two C/C preforms were prepared by the chemical vapor infiltration of pyrocarbon into needle-punctured carbon fiber felts to a density of 1.5 g/cm3,followed by or without graphitization at 2300℃. The two preforms were first treated in a KCl-LiCl molten salt mixture(mol/mol=59:41) containing 10 wt% ammonium molybdate at 1000 ℃ for 1 h to form a Mo2C layer on pore walls of the preforms,then leached with deionized water to remove the KCl and LiCl,and finally vacuum-infiltrated with liquid cop-per at 1200 ℃ for 1 h to obtain C/C-Cu composites. Results indicate that the thicknesses of the Mo2C layers are 2.5 and 3 μm for the preforms with and without graphitization,respectively. The Mo2C layer improves the wetting of the pore walls by copper,which makes the copper infiltration complete. Local Raman spectroscopy shows that the intensity ratio of the G and D bands of the pyrocar-bon is higher near carbon fibers while this trend is reversed after the molten salt treatment,indicating that the Mo2C layer causes cat-alytic and stress-induced graphitization effects for the pyrocarbon in both preforms.%采用熔盐法在炭/炭(C/C)坯体内部孔隙表面制备Mo2C改性层后,真空熔渗纯Cu制备出C/C-Cu复合材料,研究复合材料制备过程中热解炭的显微组织结构演变.结果表明,具有不同石墨化度的C/C坯体经Mo2C涂层改性后,Cu相均可充分填充改性坯体内及Mo2C涂层内部的孔隙,获得致密性较好的C/C-Cu复合材料.经Mo2C涂层改性后,C/C-Cu复合材料中热解炭的结构有序度提高,且越靠近Mo2C涂层热解炭的有序度越高.另外,采用拉曼光谱分析了热解炭结构有序度提高的原因.
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