界面改性对SiC_p/Cu复合材料热物理性能的影响

Effect of Interfacial Modifying on Thermophysical Properties of SiC_p/Cu Composites

采用热压烧结法成功制备SiC_p/Cu复合材料。采用溶胶-凝胶工艺在SiC颗粒表面制备Mo涂层,研究Mo界面阻挡层对复合材料热物理性能的影响。结果表明:过氧钼酸溶胶-凝胶体系能够在SiC颗粒表面包覆连续性、均匀性较好的MoO_3涂层,最佳工艺配比为SiC∶MoO_3=5∶1(质量比)、过氧化氢∶乙醇=1∶1(体积比),SiC表面丙酮和氢氟酸预清洗处理有利于MoO_3涂层的沉积生长。MoO_3在540℃第一步氢气还原后转变为MoO_2,MoO_2在940℃第二步氢气还原后完全转变为Mo,Mo涂层包覆致密完整。热压烧结SiC_p/Cu复合材料微观组织致密均匀,且相比原始SiC颗粒增强的SiC_p/Cu,经溶胶-凝胶法界面改性处理的SiC_p/Cu复合材料热导率明显提高,SiC体积分数约为50%时,SiC_p/Cu复合材料热导率达到214.16W·m^(-1)·K^(-1)。

SiC_p/Cu composites were successfully fabricated by vacuum hot-pressing method.Molybdenum coating was deposited on the surface of silicon carbide by sol-gel method.The effects of the interfacial design on thermo-physical properties of SiC_p/Cu composites were studied.The results indicate that：continuous and uniform MoO_3 coating can be deposited on the surface of silicon carbide by peroxomolybdic acid sol-gel system,and the best processing parameters are as follows：SiC∶ MoO_3=5∶1（mass ratio）,H_2O_2∶C_2H_5OH=1∶1（volume ratio）,and surface pretreatment with acetone and hydrofluoric acid is good to the deposition and growth of MoO_3 coating.After hydrogen reduction at540℃for 90 min the MoO_3 is changed into MoO_2,and then hydrogen reduction at 940℃for 90 min the MoO_2 is changed into Mo absolutely,and the Mo coating is continuous and uniform.SiC_p/Cu composites prepared by vacuum hot-pressing method show a compact and uniform microstructure,and the thermal conductivity of the composites is increased obviously after the Mo coating interfacial modification,which can reach 214.16W·m^（-1）·K^（-1） when the volume of silicon carbide is about 50%.