Effect of trace Fe doping on the hydrogen reduction behaviors of WO₃ powders

Tungsten powders without and with Fe doping (0.1% and 1.0% in mass fraction) were prepared by liquid‒solid doping and two-step hydrogen reduction method, respectively. The influences of trace Fe on the reduction behaviors of WO₃ powders and the microstructure characteristic of W powders were systematically studied. The results indicate that the Fe-containing solid solution is formed in the surface crystal lattice of WO₃ particles after doping and calcination. In the process of hydrogen reduction, Fe solution can reduce the reaction temperatures of WO_2.9→WO₂ and WO₂→W, promote the formation of micro-cracks and holes in the WO₃, and refine the particle size of tungsten powders. After reduction, Fe migrates from the surface of WO₃ particles to the interior of tungsten particles, and the Fe distribution changes obviously.