Tungsten Copper Gradient Heat Sink Material

Tungsten has high melting point, high hardness and other excellent performance, copper has good electrical conductivity. W-Cu composites composed of tungsten and copper have good thermal conductivity, electrical conductivity and low thermal expansion coefficient. At present, W-Cu composites are used in large scale integrated circuits and high-power microwave devices as electronic packaging materials and heat sink materials such as substrates, connectors and heat dissipation parts. 

With the high power of electronic components and more stringent working conditions, the uniform W-Cu heat sink material is difficult to meet the requirements of heat dissipation. Therefore, it is considered to be an effective way to solve this problem by developing the tungsten copper heat sink material which is formed along the thickness direction.

The design of tungsten copper gradient heat sink is mostly based on the principle of reverse design. First, the actual structure and working conditions of the material are determined. Based on these information, we choose the transition performance and microstructure, as well as the preparation and evaluation methods. After determining the composition of each layer, the theoretical density, volume modulus, thermal conductivity and thermal expansion coefficient of the gradient layers can be obtained according to the Kern mixing rule.

The ideal tungsten copper gradient heat sink material is a continuous change from the high tungsten content to the high copper content along the thickness direction. However, the continuous gradient materials have great difficulties in the preparation and precise control of the composition. The main preparation methods of W-Cu gradient materials include infiltration, ion spraying and laminating powder metallurgy.

Tungsten copper gradient heat sink material is the application of gradient function material design thought. Due to the characteristics of tungsten and copper, there are still many works to be perfected in composition design, preparation and sintering. The development of W-Cu heat sink material with variable thickness along the thickness direction has been the goal pursued by researchers. Although some methods can prepare continuous graded materials at present, they are far from enough, and more advanced preparation technologies are needed.

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