赋形造孔对钽粉电性能的影响

The Influence of Shaping and Pore Formation on the Electrical Properties of Tantalum Powder

  • 摘要: 以K2TaF7为原料,采用金属钠还原—赋形造孔—高温烧结—脱氧工艺制备了电容器用高压高比容钽粉,系统研究了赋形造孔对钽粉微观形貌、孔隙结构和电性能的影响。用激光粒度分布仪(LDSA)、场发射式扫描电镜(FESEM)和3H-2000PS2型静态容量法孔隙度分布测试仪对钽粉的粒度分布、微观形貌和孔隙结构进行表征,并将由该钽粉制成的阳极进行湿式电性能检测。上述研究结果表明:赋形造孔能改善颗粒内部团聚体的分散性。赋形造孔后的还原粉经高温烧结、脱氧后颗粒内部小于0.5 μm的微细孔隙减少,团聚体均匀一致,团聚簇少;高压(100 V以上)赋能时钽粉烧结阳极的重量比容高,漏电流小,损耗小。

     

    Abstract: High-voltage, high-specific-capacitance tantalum powders for capacitors were prepared using K2TaF7 as raw material via a process involving sodium reduction, shaping and pore-forming, high-temperature sintering, and deoxidation. Effects of the shaping and pore-forming treatments on microstructures, pore architecture, and electrical properties of the tantalum powders were systematically investigated. The particle size distribution, morphology and pore structures were characterized using laser diffraction size analysis (LDSA), field-emission scanning electron microscopy (FESEM), and a 3H-2000PS2 static volumetric porosity analyzer. The wet electrical performance of anodes fabricated from the resulting powders was also evaluated. The results demonstrated that the shaping and pore-forming treatments could improves the dispersion of internal agglomerates within the particles. After high-temperature sintering and deoxidation, the treated powders exhibited a reduction in micropores smaller than 1.0 μm, more uniform agglomeration state, and fewer agglomerated clusters. Anode samples sintered from these powders, when anodized at high voltage (above 100 V), can exhibit high specific capacitance, low leakage current and low dissipation factor.

     

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