Cathodic polarization behaviour of Nb-Ni alloys in a concentrated KOH solution

Abstract

The cathodic polarization curves of a series of Nb-Ni alloys were measured in a 25 wt.% KOH solution at 25 °C. It was found that a sharp decrease in the hydrogen overpotential occurred when the nickel content of the alloy was increased in the δ + γ region (about 0–40 wt.% Ni). The Nb-31 wt.% Ni alloy, which was composed mainly of the γ phase, had the lowest hydrogen overpotential among the alloys tested. This alloy, however, disintegrated easily owing to the formation of a hydride during cathodic electrolysis. In order to avoid this disintegration during electrolysis the alloys must contain more than 47 wt.% Ni.