Medium blue tungsten oxide may be used to produce metal tungsten (W) powder. The blue tungsten oxide (BTO) may be made into W powder by reduction method. Certainly, BTO may also be obtained by reducing yellow tungsten oxide.
There are four methods for reducing W powder with industrial value: carbon reduction method, carbon-containing gas reduction method, decomposition ammonia reduction method, and hydrogen reduction method. Among them, the most widely used method is hydrogen reduction method.
The W powder obtained by reduction method has a particle size of 0.3~30μm, and its color changes with the particle size. The finer the particle size of powder, the darker the color. The corresponding colors of tungsten powder with different particle sizes are as follows:
1. Coarse tungsten powder is gray and has a metallic highlight.
2. The medium tungsten powder is ash black.
3. Ultrafine tungsten powder is dark black.
The fine tungsten powder has a large surface activity and is easy to absorb moisture and be oxidized if it is exposed to air. Ultrafine tungsten powder is easily oxidized to tungsten trioxide without purification.
More details, please visit:
http://www.tungsten-powder.com/Blue-Tungsten-Oxide.html
