Electrodeposition of niobium from molten salts

Abstract

Niobium as well as the other refractory metals (4th, 5th and 6th columns of periodic table of elements), except chromium, cannot be electrodeposited from aqueous medium. Nevertheless, these metals can be obtained from alkali halides due to the high decomposition voltage of these solvents. Electrodeposition can be divided into electrowinning, electroplating, electrorefining and electroforming. The aim of this work is to present our results on the three latter topics for niobium in alkali fluoride melts. The effect of electrolysis parameters, such as cathodic current density and temperature on current efficiency, deposit morphology, microstructure, grain size and niobium purity is discussed. Niobium electroplating was performed on wires, tubes, plates and cathodes of complex shapes in order to study the influence of the cathode shape and the anode-cathode distance on coating distribution. Corrosion data of niobium electroplates in mineral acid media are also shown. Some Nb electroforms are also presented. © 2011 Nova Science Publishers, Inc. All rights reserved.