The electrochemical behavior of β-phase in the Cu30Ni-H system in sodium hydroxide solutions

The electrochemical behavior of Cu30Ni alloy hydride in 1 N NaOH solution was studied. One-shot and cyclic voltammograms, chronocoulometric, amperometric, and potentiometric curves, as well as time variation of the open-circuit (free-corrosion) potential E-cor, were measured. Both types of voltammograms show a limiting current plateau, which can be explained by a preceding chemical reaction of the hydride decomposition. It is concluded (from the character of E-cor vs- t curves) that the hydride decomposition involves the alloy's copper component activation through the copper oxide reduction with hydrogen. The alloy hydride decomposition rate was determined by using chronocoulometry: V = 4.6 x 10(-4) A/cm(2). No potential arrest was observed in the E-cor VS. t and E vs. t curves, which is due to concurrent reactions of electrochemical and chemical recombination involving hydrogen atoms adsorbed at the alloy surface.