Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Preparation of Niobium Powders for Solid Electrolyte Capacitors through Hunter Process Using Metallothermic Reduction Method
Jae-sik YoonJae-yeol YangJi-myon LeeSoon-jik Hong
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2013 Volume 54 Issue 1 Pages 114-118


The niobium capacitor shows somewhat more unstable characteristics than the commercial tantalum capacitors, but it will be nonetheless considered as an excellent substitute of tantalum capacitors in the future. In this study, niobium powder is fabricated by metallothermic reduction process using K2NbF7 as a raw material, KCl and KF as diluents, and Na as a reducing agent. The niobium particle size greatly decreases from 0.7 to 0.2 µm as the amount of diluent increases. However, when a higher surface area of niobium powder is desired, more amounts of diluents are used in the said method. The niobium powder morphology and particle sizes are very sensitive to the amount of sodium excess, thus the particle size of niobium powder increases with increases in the amount of sodium excess. When more diluent and sodium are used, the niobium powder is contaminated further by impurities such as Fe, Cr, Ni and others.

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© 2012 The Japan Institute of Metals and Materials
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