感应等离子体制备高纯致密球形钼粉研究

Study on the preparation of dense spherical molybdenum powders with high purity via induction plasma

摘要:

采用感应等离子体实现了钼粉的球化、致密化、细化和纯化，制备出高纯致密球形钼粉，同时研究了感应等离子体功率和原料粉粒度对球化率的影响。采用扫描电子显微镜、X射线衍射仪和激光粒度分析仪对球化处理前后粉末的形貌、物相和粒度分布进行测试和分析。结果表明，形状不规则的原料钼粉，经等离子体球化处理后得到球形度好、表面光滑、分散性良好、球化率几乎可达100%的球形钼粉。球化处理后，钼粉粒度变细，且粒度分布更集中。相同工艺条件下，随着等离子体功率的增加，钼粉的球化率先增大后降低，当等离子体功率为25kW时钼粉球化效果最好，粒度较小的钼粉球化率较高。随着钼粉球化率的提高，粉末的流动性和松装密度得到显著改善。钼粉末的流动性由40s／50g提高为11s／50g，松装密度由2.3g／cm3提高到6.1g／cm3。

Abstract:

Using induction plasma, spheroidization, densification, refinement and purity of molybdenum powder were realized, Dense spherical powders with high purity were prepared. The effects of the plasma power and particle size of raw molybdenum powder on spheroidization efficiency of products were studied. The phase composition，morphologies and particle size distributions of the powder before and after spheroidization were characterized by x-ray diffraction(XRD),scanning electron microscopy(SEM) and laser micron sizer(LMS).The result show that the spherical molybdenum powder can be obtained from irregular powder after induction plasma spheroidization. The powder presents smooth surface and good disparity, and the spheroidization efficiency is almost 100%.After plasma treatment, the particle size become finer and its distribution is more concentrated. Under otherwise identical conditions, ,spheroidization efficiency increases firstly and then decreases with the increasing of plasma power. When the plasma power is 25kW,the effects of spheroidization is best. Smaller the particle size, higher the spheroidization efficiency is. With the increasing of spheriodization efficiency, the powder flow ability and apparent density have been significantly improved. The molybdenum powder flow ability is improved from 40s／50g to 11s／50g, and the apparent density from 2.3g／cm3 to 6.1g／cm3.