【摘要】 采用熔盐法对低密度C/C复合材料进行Mo₂C改性,分析Mo₂C形成机理以及熔剂组成和反应温度对制备Mo₂C改性C/C复合材料的影响,研究了Mo₂C改性对C/C复合材料微观组织结构的影响。结果表明:仲钼酸铵与C反应生成Mo₂C的过程主要由3个阶段组成:仲钼酸铵分步分解为MoO₃,MoO₃还原为MoO₂,MoO₂与C反应生成Mo₂C;适宜的反应参数为:以LiCl-KCl为熔剂,反应温度为1000℃;Mo₂C颗粒在C相表面形核后首先形成花状聚集的Mo₂C涂层,并随反应温度提高最终形成完整的Mo₂C层;Mo₂C与C界面结合良好,生成Mo₂C过程的催化石墨化和应力石墨化作用使基体炭的有序度提高。更多还原

【Abstract】 Low-density C/C composite was modified with Mo₂C interlayers through a molten salt method. The formation mechanism of Mo₂C layers was analyzed; the effects of flux composition and reaction temperature on the fabrication of Mo₂C interlayers were studied; the influence of Mo2C-modification on the microstructure of C/C composite was also observed. Results show that the reaction between ammonium paramolybdate and C for the formation of Mo₂C layers mainly consists of three steps: decomposition from ammonium paramolybdate to MoO₃, reduction of MoO₃ to MoO₂, and carbonization of MoO₂ to Mo₂C. The appropriate flux is Li Cl-KCl and the suitable reaction temperature is 1000 °C according to the experimental results. Flower-like Mo₂C layers are formed and then continuous Mo₂C layer covers the surface of C phase with the increase of reaction time and temperature. The Mo₂C/C interface shows good bonding state. The pyrolytic carbon phase near the interface exhibits high order degree as a result of catalytic graphitization and stress graphitization. Modification of Mo₂C interlayer for the C/C composite can facilitate the infiltration of Cu and its joining with Cu.更多还原