Compared with ordinary tungsten powder, the particle size of submicron tungsten powder is smaller, about 200nm, and has higher chemical activity and larger specific surface area. The oxygen content of the powder can be controlled below 1% after passivation.
The preparation method of tungsten powder includes hydrogen reduction of tungsten trioxide or ammonium para-tungstate. The method is generally divided into two stages:
In the first stage, the tungsten trioxide is reduced to tungsten dioxide at a temperature of 500-700°C. In the second stage, the tungsten dioxide is reduced to tungsten powder at a temperature of 700 to 900°C.
It is worth noting that the performance of reduced tungsten powder (such as purity, particle size, particle size composition, etc.) mainly depends on the reduction process. When reducing tungsten powder in a tube furnace, the main process parameters that affect the reduction rate are the reduction temperature, the loading of tungsten oxide in the burning boat, the moving speed of the burning boat, the flow rate of hydrogen, and the moisture content in the hydrogen.
In addition to the hydrogen reduction method, tungsten powder is prepared by the tungsten oxide carbon reduction method used earlier, and the reduction temperature is higher than 1050°C. However, the purity of tungsten powder obtained by this method is low.
1. It can be used to prepare tungsten products such as high specific gravity alloys, turning tools, drill bits, and molds.
2. It can be used as an additive for the raw material powder of high-performance and high-density alloys (the addition amount ranges from 10% to 20%) and as a raw material additive for tungsten rods and tungsten wires. This can significantly improve the properties of the alloy while reducing the sintering temperature and shortening the sintering time, saving production costs.
3. Submicron tungsten powder can be used as the raw material of nano-tungsten carbide, which can produce high-quality cemented carbide and ferro-tungsten. Because the material has a special pore structure, it can also be used to produce ceramic metalized coatings.
Thank you for reading our article and we hope it can help you to have a better understanding of the submicron tungsten powder. If you want to learn more about tungsten or other types of refractory metals, we would like to advise you to visit Advanced Refractory Metals (ARM) for more information.
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