Research Of Diamond/Copper Composite Interface Characterization And Control

In recent years, electronic cooling problems have caused high attention and concern internationally. With the miniaturization, multi-functionalization and compact size of electronic components, the relative heat flow and calorific value of electronic components become increasingly higher, which raise higher requirement of heat dissipation of the device. The key problem of electronic cooling lies in efficient thermal conductivity, which can be effectively solved by studies on heat management with high thermal conductive composite. Because interface is the weak link of high thermal conductive composite, and is also the key factor that affect its performance, the interface characterization and regulation of Diamond/Cu composite are of great significance.In this paper, the pressure melt infiltration method was applied in preparation of Diamond/Cu composite, and its interface was studied deeply and systematically. In addition, the author further analyzed the impact of different types of interfaces on Diamond/Cu composite physical properties. By reducing the number of Diamond/Cu composite interfaces and controlling Diamond/Cu composite interface residual impurities, researchers manufactured perfect interface Diamond/Cu composites through high-pressure infiltration method, and then initially achieved the interface control, which laid the foundation for Diamond/Cu composite interface design.In the pressure infiltration of Diamond/Cu composite process, when the matrix alloying elements was Cr0.8wt%, the Diamond/Cu composite interface bonding reach optimal state. A small number of chromium carbide generated in interfacial reaction of Cr and Diamond scaly distributed in the copper matrix close to interfacial region. Most chromium carbide elements piled up to a stratifor m structure with the thickness about397nm. The chromium carbide layer near the end of diamond was Cr3C2, while near the end of the copper was CryC3.By using the Ⅱ binder, the thermal conductivity of Ⅱ-Diamond/CuCr0.8%was relative higher,595W/m-K. The flexural strength of Ⅰ-Diamond/CuCr0.8%composite materials and Ⅱ-Diamond/CuCr0.8%composites were501MPa,556MPa respectively. The interfacial thermal resistance ratio of Ⅱ-Diamond/CuCr0.5%composite, Ⅰ-Diamond/CuCro.8%composite, and Ⅱ-Diamond/CuCr0.8%composite was2.41:2.16:1. By changing the diamond particle size, and controlling the number of Diamond/Cu composite interfaces, we achieved the regulation of its interface thermal resistance. When diamond particle size were80μm,180μm, the interfacial thermal resistance of B-Diamond/Cu composite was2.165×10"8m2K/W, which was0.71times of A-Diamond/Cu composite (3.058x10" m K/W). Further, the thermal conductivity of Ⅲ-Diamond/Cu composite was620W/m-K., with no additives binder. The interfacial thermal resistance of Ⅲ-Diamond/Cu composite was1.891×10’8m2K/W, which was0.34times of Ⅰ-Diamond/Cu composite interfacial thermal resistance (5.625×10"8m2K/W), and was0.73times of Ⅱ-Diamond/Cu composite interfacial thermal resistance (2.598x10-8m2K/W).Diamond/Cu composites with perfect interface were produced with the method of pressure infiltration. Because some diamond elements realized polycrystalline, and thermal channels were formed, some of the interfacial thermal resistances were replaced by the grain boundary thermal resistance between the particles, thus fundamentally reducing the interfacial thermal resistance. The thermal conductivity of Diamond/CuCro.8%and Diamond/CuNi3o%were separately up to700W/m-K and650W/m-K.