Electrochemical dissolution of nichrome in sulphuric acid

The paper reports polarisation studies on the dissolution of nichrome in di fferent concentrations of H2SO4 at room temperature. The cathodic current d ensity (i(c)) and anodic current density (i(a)) at fixed over-potential, to gether with the corrosion current density (i(corr)), are found to be propor tional to H2SO4 concentration, whereas they decrease progressively at highe r Na2SO4 concentration, the H2SO4 concentration being maintained at 1.0 M. Anodic polarisation studies indicate that passivity becomes more difficult at increased acid concentrations, whereas an increase in the sodium sulphat e concentration decreases not only the open-circuit corrosion potential, bu t also the passive current (i(p)). The Langmuir adsorption isotherm was use d to establish the mechanism of the process. (C) 2001 Elsevier Science B.V. All rights reserved.