Electrochemical dissolution of nichrome in sulphuric acid

The paper reports polarisation studies on the dissolution of nichrome in different concentrations of H2SO4 at room temperature. The cathodic current density (ic) and anodic current density (ia) at fixed over-potential, together with the corrosion current density (icorr), are found to be proportional to H2SO4 concentration, whereas they decrease progressively at higher 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 sulphate concentration decreases not only the open-circuit corrosion potential, but also the passive current (ip). The Langmuir adsorption isotherm was used to establish the mechanism of the process.