CATHODIC HYDROGENATION OF COPPER AND CU30NI ALLOY IN SULFURIC-ACID-SOLUTIONS

The anodic behavior of samples of copper and Cu30Ni alloy hydrogenated in advance by cathodic polarization (i(c) = 0.05 A/cm2, t = 2 h) in s ulfuric acid solutions was studied by a combination of radioisotope an d electrochemical measurements. It was found that the amount of hydrog en absorbed by COPPer (m(H) = 6-10(-8) g/cm2) is about 20 times lower than that absorbed by nickel hydrogenated under the same conditions. D uring anodic polarization of the hydrogenated alloy, the net current i (a) initially is consumed exclusively for hydrogen ionization (i(a) = i(H)), then the partial rates of copper and nickel ionization increase and i(H) decreases. Here m(H) is about 2.5 times lower than it is in nickel. It was found that copper is dissolving selectively from the al loy so long as hydrogen absorbed by the alloy is ionized. This effect is explained by nickel atoms at the alloy surface being inhibited by h ydrogen.