Nano Tungsten Copper Mixed Powder of Tungsten Copper Electrode Preparation

Compared with traditional powder metallurgy (PM), tungsten copper electrode nano composite material including powder milling, compacting and sintering process, but due to the characteristics of nano particles, there are some differences between traditional powder metallurgy and nano tungsten copper mixed powder preparation.

1. Direct mixing

The nano tungsten powder and copper powder directly mixed according to a certain proportion, which has many methods, such as ultrasonic mixing, mechanical stirring, ball milling and so on. The mixing process should at the inert gas atmosphere, otherwise the nano powder will be oxidized easily.

2. Mechanical alloying (MA)

MA refers to the W, Cu metal powder stirring energy ball milling, high energy planetary ball mill or rotor, while using inert gas to prevent oxidation of the powder during the milling process. In the process of mechanical alloying, collision with a metal ball leaving the powder on powder body ingot refining, and mixing the powder collision between recurrent, so that each element powder blended to achieve a very uniform degree and form of nano crystalline supersaturated solid solution and amorphous phase. In addition, the facility and conditions it required is simple, which is the most widely studied by the researchers and scholars in the world.

3. Composite powder coreduction

Owing to tungsten oxide and copper oxide are easily reduced to the metal by hydrogen (H2), Uses composite powder reduction to prepare a uniform distribution of tungsten-copper composite powders has been one of the hot researches. n recent years, researchers have found that using a special co-reduction method can be directly sintered into dense tungsten-copper composite powder having a uniform fine grain structure, there are some applied to the preparation of parts for industrial use.

There are two methods to the powder preparing, one is that tungsten oxide and copper oxide powder are mixed with water pulping, grinding, spray drying, and reduction with hydrogen was obtained spherical powder, powder of tungsten phase and a copper phase distribution more uniform, wherein the particle size of the tungsten 1-3μm. Then the spherical powder can be pressed and sintered to obtain a dense, fine-grained tungsten-copper composite material. Another is uses ammonium metatungstate reacted with copper oxide complex oxide, copper which is about 26%. Cu is the core, which tungsten grain surrounded by. Although this tungsten-copper composite powder pressing and sintering the resulting tungsten copper material compared to infiltration method can be better thermal conductivity properties as well as the overall performance, but the process is relatively complex, low productivity shortcomings.

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