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研究了SiC颗粒经不同氧化时间的氧化行为,采用无压渗透法制备了体积分数大于55%的SiCp/Al复合材料,分析了复合材料的微观组织与界面形貌,探讨了氧化及界面反应对复合材料热导性能的影响。结果表明:当SiC颗粒在1100℃氧化时,随着氧化时间的延长,其氧化增重及氧化层的厚度均增加,但氧化时间大于6 h时,其增加速率减缓;经氧化处理后,颗粒尖角明显钝化,所制备复合材料颗粒分布均匀,致密度比颗粒未氧化时要高;且氧化改变了复合材料的界面反应及结合,未经氧化颗粒表面出现了短棒状Al_4C_3,4 h氧化后颗粒表面形成了八面体MgAl_2O_4,6 h氧化后仍有残余的SiO_2;随氧化时间的延长,复合材料热导及界面热传导系数均呈先增大后减小的变化趋势,这与不同氧化时的实际界面状况密切相关。
The oxidation behavior of SiC particles at different oxidation time was studied. The SiCp / Al composites with volume fraction greater than 55% were prepared by pressureless infiltration method. The microstructure and interfacial morphology of the composites were analyzed. The effects of oxidation and interfacial reaction Effect of Thermal Conductivity on Composites. The results show that when the oxidation temperature is 1100 ℃, the oxidation weight gain and the oxide layer thickness increase with the increase of oxidation time. However, when the oxidation time is longer than 6 h, the increase rate of SiC particles slows down. After oxidation treatment, The sharp corners were obviously passivated, the composite particles were uniformly distributed and the density was higher than that of the unoxidized particles. The oxidation changed the interfacial reaction and bonding of the composites. The short rod-like Al 4 C 3, The octahedral MgAl 2 O 4 formed on the surface of the rear particles and remained SiO 2 after oxidation for 6 h. With the extension of oxidation time, the thermal conductivity and interface thermal conductivity of the composites increased first and then decreased, The actual interface status is closely related.