气体压力熔渗制备电子封装用金刚石/铝复合材料的研究

Study on Diamond/Al Composites Prepared by Gas Pressure Infiltration Method for Thermal Management Application

金刚石颗粒增强铝基（diamond/Al）复合材料是最受关注的新一代电子封装材料。本文采用气体压力熔渗法制备了金刚石体积分数达到65%的diamond/Al复合材料;通过对相组成及断口形貌的分析,明确了复合材料的界面优化机制及破坏方式,在此基础上,系统研究了复合材料的热物理性能和力学性能随金刚石粒度的变化规律。气体压力熔渗法制备diamond/Al复合材料可以依靠基体铝与金刚石间的扩散反应实现界面优化,显著改善界面形貌,提高结合强度,复合材料断口微观形貌则呈现出典型的塑性断裂特征;依靠两相原位反应优化后的界面可以更加有效的实现热载流子的耦合移动和应力的传递,从而保证复合材料可以获得更为优异的热导率和力学性能;随着金刚石颗粒直径减小,两相界面的影响得以加强,因此复合材料热导率降低,热膨胀系数小幅减小,而力学性能提高,在本文选择的粒度范围内（30～150μm）,复合材料的热导率、热膨胀系数以及抗拉、抗压、抗弯强度的相应变化区间分别为400～760 W·m^-1·K^-1、4.5～5.3×10^-6K^-1、143～94 MPa、603～363 MPa和429～277 MPa。

Diamond particles dispersed aluminum matrix（ diamond /Al） composite is the promising candidate for new thermal management materials.In this paper,the diamond /Al composites with diamond volume fraction above 65% were fabricated by gas pressure infiltration method.The phase composition and fracture surface were analyzed to determine the interfacial optimization mechanism and failure mold of the composite.Further,the evolution of the thermo-physical and mechanical properties of composites with diamond particle size was investigated.During the gas pressure infiltration process,the diffusive reaction between aluminum matrix and diamond particle is activated,which can significantly optimize the interface in terms of improving the microstructure and enhancing bonding strength.Accordingly,the microscopic fracture morphology of the composites shows the typical characteristics of ductile break of metal matrix.The optimized interface can more effectively accomplish the coupling and movement of thermal carriers and transfer of stress.Therefore,the diamond /Al composites fabricated by gas pressure infiltration method achieve the better thermal conductivity and other properties.Due to the reduction of diamond particle size intensifying the effect of interface,the composites exhibit the reduced thermal conductivity,slightly lowered coefficient of thermal expansion（ CTE）,and enhanced mechanical properties.Within the scope of the selected diamond diameters in this paper（ 30-150 μm）,the thermal conductivity,CTE and mechanical properties including the tensile,compressive as well as bending strength correspondingly change in the range of 400-760 W·m^-1·K^-1,4.5-5.3 ×10^-6K^-1,143-94 MPa,603-363 MPa and 429-277 MPa,respectively.