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摘要: 采用液–固掺杂结合两步氢还原法分别制备未添加和添加质量分数0.1%和1.0%Fe的金属W粉，研究了微量Fe元素对WO3还原过程及产物结构特征的影响。结果表明：WO3前驱体粉体经掺杂和煅烧处理后，在其颗粒表层晶格中形成了含Fe固溶体；在氢气还原过程中，Fe的固溶能够降低WO2.9→WO2和WO2→W的还原温度，促进WO3中裂纹和空隙的产生，细化还原W粉尺寸；还原后Fe元素由偏聚在WO3颗粒表面迁移到W颗粒内部，其分布规律发生了明显转变。Abstract: 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 WO2.9→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.
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Key words:
- trace Fe /
- tungsten powders /
- hydrogen reduction /
- doping /
- ultrafine powders
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图 1 固–液掺杂法制得的WO3和WO3–Fe粉末X射线衍射图谱
Figure 1. XRD patterns of WO3 and Fe-doped WO3 powders by liquid-solid doping
图 2 WO3和WO3–1.0Fe粉末W 4f（a）和WO3–1.0Fe粉末Fe 2p（b）高分辨X射线光电子能谱
Figure 2. W 4f XPS patterns of WO3 and WO3–1.0Fe powders (a) and Fe 2p XPS spectra of WO3–1.0Fe powders (b)
图 3 WO3–1.0Fe粉末透射电镜表征结果：（a）低倍透射电镜形貌；（b）表层高分辨透射电镜形貌；（c）近表层高分辨透射电镜形貌；（d）高角环形暗场图像及能谱线扫描图谱
Figure 3. TEM analysis of WO3–1.0Fe powders: (a) low magnification TEM image; (b) high resolution TEM images at the outer area; (c) high resolution TEM images at the inner area; (d) HADDF image and EDS line scanning spectra
图 5 还原W粉X射线衍射图谱
Figure 5. XRD patterns of the tungsten powders after hydrogen reduction
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