Corrosion of nickel in acid solutions with hydrogen sulphide

Abstract

The corrosion behavior and dissolution mechanism of nickel in acid solutions with hydrogen sulphide (H 2S) is studied. Results show that the dissolution of nickel is under both the influence of the nickel sulphide layer formed on the electrode surface and the acceleration effect of H 2S. 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 H 2S. This is attributed to the corrosion-hindering effect of the nickel sulphide layer. The hindering effect of the sulphide layer formed in the lower polarization range increased with both solution pH and H 2S concentration. When the polarization potential increased into the higher polarization potential range, however, no obvious hindering effect of nickel sulphide layer on the anodic dissolution of nickel could be observed. A mechanism for the anodic dissolution of nickel in acid solutions with H 2S is proposed.