Micromorphology and texture of niobium coating electrodeposited in NaCl—KCl—CsCl molten salt system

Abstract

A low-toxicity and environment-friendly NaCl—KCl—CsCl—K2NbF7 system was used to prepare Nb coatings on Mo substrates. The effects of temperature, current density and electrodeposition time on the micromorphologies and textures of the electrodeposited Nb coatings were studied. The results showed that Nb coatings obtained at 30—70 mA/cm2 in the temperature range of 700—750 °C were continuous and compact, with a hardness range of 2.16—2.45 GPa. As the columnar crystals grew with time, the preferential growth orientations of the Nb coatings changed from 〈200〉 to 〈211〉 and then became disordered. With increasing polarization, the morphologies of the Nb coatings changed from hexagonal star-like surface to conical or pyramid-like surface.