中文摘要：

为了制备具有良好的热导率、热稳定性、导电性和柔顺性的纳米颗粒填充硅树脂复合材料,首先以乙基封端聚二甲基硅氧烷（PDMS）为基体材料,以碳包钴纳米颗粒（C@Co）为填料,采用研磨共混法制备了C@Co/PDMS复合热界面材料。然后,运用TEM、XRD、Raman和SEM分别对C@Co的微观结构、物相、石墨化程度和分散性进行了研究。最后,研究了C@Co含量对复合热界面材料的热导率、热稳定性、导电性和柔顺性的影响。结果表明：该复合热界面材料的热导率随着C@Co含量的增加而增大,当C@Co的含量为24wt%时,复合材料的热导率达到最大值1.64 W/（m·K）,比纯PDMS的提高了10.7倍;TG分析表明,添加24wt%的C@Co后,复合材料的起始分解温度和最终分解温度比纯PDMS的分别提高了约70℃和80℃,说明C@Co能提高复合材料的热稳定性;随着C@Co含量的增加,复合热界面材料的电导率非线性增大,拟合试差计算的逾渗阀值为10wt%,即C@Co含量小于10wt%时复合材料的绝缘性良好,而填充24wt%的C@Co时复合材料的电导率为9.38×10^-3 S·m^-1;复合材料的硬度适中,处于17.6-26.8HA范围内,表明该复合材料的柔顺性较好。因此,24wt%C@Co/PDMS复合材料不仅能满足热界面材料电性能的基本要求,且具有良好的热导率、热稳定性和柔顺性。

英文摘要：

In order to prepare the nanoparticles filling silicone composites with favorable thermal conductivity,thermal stability,electrical conductivity and flexibility,vinyl terminated polydimethylsiloxane（PDMS）was used as matrix material and carbon coated cobalt nanoparticles（C@Co）was used as filler,C@Co/PDMS composite thermal interface materials were prepared by ground co-blend method firstly.Then,TEM,XRD,Raman,and SEM were employed to investigate the microstructure,phase,degree of graphitization and dispersibility of C@Co.Finally,the effects of C@Co content on thermal conductivity,thermal stability,electrical conductivity and flexibility of composite thermal interface materials were investigated.The results show that the thermal conductivity of the composite thermal interface materials increases with the C@Co content increasing,when the C@Co content is 24wt%,the thermal conductivity of the composite reaches the maximum 1.64 W/（m·K）,which is 10.7times higher than that of neat PDMS.TG analysis indicates that after the addition of 24wt% C@Co,the initial decomposition temperature and final decomposition temperature of composites increase about 70 ℃ and 80 ℃ comparing to that of the neat PDMS respectively,accounting for C@Co can enhance the thermal stability of the composites.With the C@Co content increasing,the electrical conductivity of the composite thermal interface materials increases nonlinearly,and the percolation threshold value of fitting trial and error calculation is 10wt%,which means that when the C@Co content is less than 10wt%,the insulativity of composite is favorable;but when filled with 24wt% C@Co,the electrical conductivity of composite is 9.38×10^-3 S·m^-1.The hardness of composites is moderate,which is in the range of17.6-26.8HA and indicates that the flexibility of the composite is preferable.Therefore,24wt% C@Co/PDMS composite can not only meet the basic requirements of the electrical properties of thermal interface materials,but also have favorable thermal conductivity,thermal stab