| The electrode current-potential relationships of each nickel and chrome layers in various aqueous solutions have been measured, and the corrosion currents were obtained by coupling above results to investigate the mechanism of corrosion of iron or some other metal articles on which multiple layers of nickel, followed by a layer of chrome, were electroplated. The innermost dull or semibright nickel layer showed the most noble potentials at all range of current densities and in any reaction environments considered, and the next bright nickel layer showed the alternating potential with the outermost chrome layer at above conditions. Since the corrosion potential and the corrosion current in the bright nickel and chrome layers were quite small, corrosion in expected to proceed at the same time on both layer, and it would take a long time to reach upto the innermost dull or semibright nickel layer. As a result, corrosion protection of basis metals would be accomplished. The corrosion currents were comparatively small in alkaline and reducing atmospheres, whereas they were lager in acidic and oxidizing conditions. |
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