Effect of Y2O3 doping on preparation ultrafine/nano-tungsten powder and refinement mechanism

In this study, ultrafine/nano W–Y2O3 composite powders were synthesized by spray drying, roasting and two-step hydrogen reduction using ammonium metatungstate and yttrium nitrate as raw materials. The mechanism of the influence of Y2O3 on the growth of WO2.72 and the particle refinement of tungsten powder is discussed. The effect of Y2O3 particles on the reduction behavior of tungsten powder was investigated using scanning electron microscopy to study the near surface morphology and X-ray diffraction for phase ID (composition) and crystal structural changes for the reduced powders at each step. The results show that the doping of 0.3 wt.% Y2O3 can significantly increase the aspect ratio of WO2.72 in the first step of hydrogen reduction. Moreover, Y2O3 can effectively inhibit the growth of tungsten particles in the hydrogen reduction process. Therefore, The Y2O3-doped tungsten powders have finer particles and a narrower particle size distribution range than the undoped powders. The average particle diameter of 0.3 wt.% Y2O3 doping tungsten powder was in the range of 90–120 nm.