Tungsten Copper Electrode Internal Influence Factors

Tungsten copper materials not only has high hardness, high strength, high melting point, high density, low coefficient of thermal expansion and excellent wear and corrosion resistance of W, but also has perfect plasticity and excellent thermal and electrical conductivity of Cu, so it has been widely used in electrical contact materials and electrode materials. But since there is a big difference in melting point and physical properties of them and completely immiscible, usually choose PM (Powder Metallurgy) as the manufacturing process, which also limit the range of applications of tungsten copper. At present, the major way for the preparation of tungsten copper composite material is W-Cu composite powder high energy ball milling, pressing, sintering, by analyzing the influence of grain size and composition of the powder itself and impurities brought sintering properties, in order to better control each key parameters to achieve high-performance tungsten copper electrode products.

In general, in the process of tungsten copper electrode manufacturing, in order to improve the compacts molding effect, we need to add some chemical agents, such as ethanol, stearic acid and so on. These additives may be directly volatilize or decompose in the subsequent sintering step and form pores between the particles. When the sintering temperature is rising, liquid Cu fluidity becomes poor and the gas can not escape completely and formed closed pores, which has a great effect on the density of tungsten copper electrode. In addition, these additives also likely to break down the formation of some C, H, O and other impurities, the smaller its diameter, has a strong expansion of capacity in the alloy. Thus it more likely to occur at a position higher energy grain boundary phase boundary segregation, etc., and even generate crisp phase, bringing the number of alloy intergranular fracture during fracturing along the increase, decrease overall performance. For the powder granularity, When the powder grain size small to some extent, powder sintering temperature decreased, surface area increased, sintering activity enhanced, which is beneficial for powder alloying. When the powder particle size to the nanometer range, the diffusion of powder has been greatly improved, densification process has been accelerated, and the final density of tungsten copper electrode has been improved at the same time.

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