Corrosion of nickel in acid solutions with hydrogen sulphide

The corrosion behavior and dissolution mechanism of nickel in acid solution s with hydrogen sulphide (H2S) is studied. Results show that the dissolutio n of nickel is under both the influence of the nickel sulphide layer formed on the electrode surface and the acceleration effect of H2S. In the lower anodic polarization potential range, the anodic current of nickel electrode with a three-dimensional sulphide layer on its surface was lower than that of the electrode without sulphide layer in solutions with H2S. This is att ributed to the corrosion-hindering effect of the nickel sulphide layer. The hindering effect of the sulphide layer formed in the lower polarization ra nge increased with both solution pH and H2S concentration. When the polariz ation potential increased into the higher polarization potential range, how ever, no obvious hindering effect of nickel sulphide layer on the anodic di ssolution of nickel could be observed. A mechanism for the anodic dissoluti on of nickel in acid solutions with H2S is proposed. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.