Because violet tungsten oxide (VTO) producing process and process parameters are simple as well as equipment are easy to control and many advantages so many manufactures are like to use VTO to producing tungsten powder. VTO cycle reduction method can producing excellent performance submicron or micro tungsten powder particles, to further understand tungsten powder in the reactions process which is used cycle reduction method will conducive to the future development and maturity of this method.
After studies, VTO is first hydrogen reduced to tungsten powder and the specific surface area of tungsten oxide is 0.141m2 • g-1 and particle size mainly between 4.72-12.13um. Compared with the original VTO particle size distribution, after first reduction the particle of VTO is significantly thinner, but still existing coarse particles. The tungsten powder in the air oxidation to tungsten trioxide for the first the specific surface area of it is 0.145m2 • g-1, which is 1.13 times of VTO. It can be seen, the first time oxidized to tungsten trioxide the particle are smaller than VTO particle size which is more uniform distribution, but still significant reunion.