Title:Characteristics of Niobium Powder Used Capacitors Produced by Metallothermic Reduction in Molten Salt
VOLUME: 10 ISSUE: 1
Author(s):Jae-sik Yoon, Gae-hang Lee, Soon-jik Hong, Hyun-seon Hong, Chan-gi Lee and Ji-myon Lee
Affiliation:Korea Basic Science Institute, 169-148 Gwahangno Yusung-gu, Daejeon 305-806, Korea.
Keywords:Diluents, metallothermic reduction, niobium capacitor, raw material, reducing agent, tantalum capacitor.
Abstract: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 0.7μm to 0.2μm 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 [1,2].
