Branched morphology of Nb powder particles fabricated by calciothermic reduction in CaCl2 melt

Abstract

A new branched morphology of metallic niobium powder particles was produced by calciothermic reduction of niobium oxides in molten CaCl 2. The influence of some reaction parameters on the powder particle morphology was studied, and the formation mechanism was investigated. It was found that the formation of intermediate complex niobium oxides (Ca x Nb 2 O y) was crucial in the formation of niobium powder particles with the branched morphology. Based on this finding, the formation mechanism of the 2 branched morphology in four stages was proposed. These Nb powder particles with microscopic branches can prevent particle sintering during the fabrication process of electric capacitors, allowing the latter to exhibit a higher capacitance.

(Invited) Metal Production in CaCl2-Based Melts

“…The appearance of Ca-containing phases such as CaNb 2 O 6 , CaTa 2 O 6 and CaV 2 O 4 in the way from Nb 2 O 5 , Ta 2 O 5 and V 2 O 3 to the corresponding metals indicates the important contribution of Ca and CaO (6)(7)(8)(9)(10)(11).…”

Efeito do processo de hidrogenação na redução do tamanho de partículas de nióbio utilizadas em capacitores eletrolíticos / Effect of the hydrogenation process on reducing the size of niobum particles used in electrolytic capacitors

“…Por meio do controle da morfologia, da redução e distribuição do tamanho das partículas é possível alterar as propriedades elétricas. Por exemplo, ao reduzir o tamanho médio de suas partículas do Nb, consegue-se atingir melhores valores de capacitância [3,6]. Diante disso, algumas técnicas são estudadas para a obtenção de partículas cada vez menores [7][8][9].…”