The electrochemical behaviour of cobalt in alkaline nitrate melts at different temperatures

The electrochemical behaviour of cobalt in molten alkali nitrates in the temperature range from 141 to 321°C has been investigated. At lower temperatures the metal dissolves as Co(II); the oxidation product at higher temperatures is Co₃O₄. Nitrogen oxides are also formed. Passivation and localized corrosion occur under definite anode potential, Co(II) concentration and temperature conditions. These effects have been studied by non-stationary measurements. Co(II) dissolved in the melt can be electrodeposited either on cobalt or platinum cathodes.