Tungsten Copper Heat Sink Plasma Spraying

With the rapid development of science and technology, integrated in the microelectronics industry sectors related electronic products have become more sophisticated, the corresponding energy consumption also increased. So it places higher demands on heat sink properties, which not only required high density and strength, but also has excellent electrical conductivity, thermal conductivity and low coefficient of thermal expansion. Tungsten copper is composed of W with high hardness, high density, high strength, high melting point and low coefficient of thermal expansion and Cu with perfect electrical and thermal conductivity so that it can be an ideal material for heat sink. Furthermore, the properties of tungsten copper heat sink can be improved by the adjustment of W and Cu content.

Since there is a great difference in physical and chemical properties between W and Cu, which has 2000℃ difference in melting point. Both of them do not form a compound or solution, so it is a kind of typical pseudo alloy. Therefore, it is difficult to achieve by common pressed and sintered, the infiltration is the best way. But infiltration is easy to form pores certain deficiencies and to bring some difficulties to the subsequent processing. Plasma spraying is a strengthening of the material surface and surface-modified new multi-purpose precision spraying techniques. It uses plasma arc drove by DC as the heat source and has the following characteristics:

1. Ultra-high temperature characteristics, suitable for spraying refractory material;

2. High particle injection rate, the coating is dense and has higher bonding strength;

3. In the process of spraying, inert gas used as the shielding gas so that the coating material difficult to be oxidized.

Plasma spraying technique can make the surface of the substrate with a high temperature oxidation, thermal insulation, anti-friction, wear and corrosion, insulation, radiation protection and sealing properties, which can heat metal, alloy and ceramics to molten or semi-molten state and spray to the surface after pretreatment at high speed to form a firmly attached layer. In addition, plasma spraying also can be used in medical field, the coating layer of a few microns in artificial bone surface coating can achieve enhanced affinity for artificial bone and the strengthening effect.