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钨粉改性工艺对喂料流变性能及钡钨阴极多孔钨基体孔隙性能的影响

Influence of tungsten powder modification process on the rheological properties of feedstock and pore properties of porous tungsten matrix for barium-tungsten cathodes

  • 摘要: 采用低能球磨、气流破碎和射频等离子体球化技术对平均粒径3~5 μm的工业还原钨粉进行改性处理,将改性后的钨粉作为原料,运用金属注射成形技术制备钡钨阴极用多孔钨基体。系统研究了不同改性工艺对钨粉性能、注射过程喂料流变学特性以及最终制备所得多孔钨基体孔隙结构特征参数的影响规律。结果表明,经气流破碎处理的钨粉以及利用射频等离子体球化技术制得的钨粉呈现出粒度分布更窄、颗粒表面光滑且粉末分散性较好的特性。在采用相同粘结剂的情况下,由气流破碎处理钨粉和射频等离子体球化钨粉制备的喂料具备更高的粉末装载量,这两种钨粉制备的多孔钨基体能满足钡钨阴极的基本要求,且闭孔率低,孔隙连通性更好,孔径分布更均匀。

     

    Abstract: The industrial reduced tungsten powders with the average particle size of 3~5 μm were modified by low-energy ball milling, airflow crushing, and radio frequency plasma spheroidization technology, respectively. The modified tungsten powders were used as the raw materials, and the metal powder injection molding (MIM) technology was applied to prepare the porous tungsten matrix for barium-tungsten cathodes. The influence of modification processes on the properties of tungsten powders, the rheological characteristics of the feedstock during the injection process, and the pore structure of the finally prepared porous tungsten matrix were systematically studied. The results show that the tungsten powders prepared by airflow crushing (ACW) and radio frequency plasma spheroidization technology (SW) exhibit the characteristics of narrower particle size distribution, smooth particle surfaces, and better powder dispersibility. Using the same binder, the feedstock prepared by ACW and SW powders has the higher powder loading. The porous tungsten matrix prepared by ACW and SW powders can meet the basic requirements of barium-tungsten cathodes with low closed pore rate, better pore connectivity, and more uniform pore size distribution.

     

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