高压熔渗金刚石/铜复合材料的低温导热特性

Low-temperature heat conduction characteristics of diamond/Cu composite by high pressure infiltration

为研究高压熔渗金刚石/铜复合材料导热率在低温区的变化规律,采用高压熔渗(HRF)的方法分别制备了不同粒度(100μm,250μm,400μm)的金刚石/铜复合材料,利用扫描量热法分析评价了高压熔渗法制备的不同粒度金刚石/铜复合材料的低温导热特性,采用扫描电子显微镜(SEM)分析其显微组织。研究结果表明:由于高压熔渗制备的金刚石/铜复合材料中的部分金刚石发生聚晶反应,导致金刚石颗粒间晶界传热的热阻远小于界面传热热阻;高压熔渗条件下,金刚石颗粒内部变形破碎导致缺陷增多,且100~150K低温下以声子为主要热载子的传热对裂纹和间隙等缺陷敏感,导致在较低温区内金刚石/铜复合材料的导热率低于普通压力熔渗(PF)所制备的金刚石/铜复合材料的导热率。

In order to study variation of the thermal conductivity of the diamond/Cu composite prepared by high pressure infiltration at low temperature zone,the diamond/Cu composites with different diamond particle sizes(100μm,250μm and 400μm)were separately prepared by high pressure infiltration(HPF)method,the scanning calorimetry was used to analyze and evaluate the thermal conductivity of the diamond/Cu composites at low temperature,and SEM was used to analyze the microstructure of the composites.The results show that the thermal resistance of diamond particles in the heat transfer of grain boundary is far less than that in the interfacial heat transfer,for part of the diamond in the diamond/Cu composites prepared by high pressure infiltration becomes involved in polycrystalline reaction.The inner deformation and crushing of diamond particles result in more defects under high pressure infiltration condition,and the heat transfer with phonons as the main heat carrier at low temperatures of 100-150K is sensitive to such defects as crack and clearance.Therefore,the thermal conductivity of diamond/Cu composites prepared by high pressure infiltration method is lower than that of the composites prepared by common pressure infiltration(PF)method at low temperature.