Abstract:Tungsten nano-powders were prepared by carbon assisting hydrogen reduction using ammonium metatungstate (AMT) and glucose as raw materials. The effects of tungsten carbon molar ratio and reduction technology on the mean particle size and residual carbon amount of tungsten powders were investigated. The results show that the reduction products, the mean particle size and residual carbon amount of tungsten powders depend on the reduction temperature and tungsten carbon molar ratio, there is not apparent effect of reduction duration on the mean particle size and residual carbon amount of tungsten powders when reduction duration is more than 1 h. The reduction products depend on reduction temperature. When the reduction temperature is 700, 750 and 800 ℃, the reduction products are W+WO₂, W+W₂C+WC and W, respectively. When the tungsten carbon molar ratio increases from 1:2.0 to 1:3.0, the mean particle size of tungsten powders decreases from 98 nm to 42 nm. The residual carbon amount of tungsten powders is less than 0.05% (mass fraction) when the tungsten carbon molar ratio is less than 1:2.6, but the continuous increase of the tungsten carbon molar ratio results in the significant increase of the residual carbon amount of tungsten powders. Tungsten nano-powders without obvious agglomeration are prepared by the carbon assisting hydrogen reduction of the precursor with tungsten carbon molar ratio of 1:2.6 at 800 ℃ for 1 h. The mean size and residual carbon amount of tungsten nano-powders are 46 nm and 0.05% (mass fraction), respectively.

Key words: tungsten nano-powder; carbon assisting hydrogen reduction; reduction temperature; reduction time