Influence of sodium chromate and dodecylamine on enhanced dissolution behavior of Cu—Ni alloy induced by AFM tip scratching

The influence of two inhibitors sodium chromate and dodecylamine on enhanced dissolution of Cu–Ni alloy initiated by atomic force microscopy (AFM) tip scratching in 1.5 M NaCl and 0.01 M HCl was investigated. The lateral force traces and force versus distance curves were measured by AFM in distilled water without or with inhibitors to investigate the influence of inhibitors on physical characters of sample surfaces. The results indicated that enhanced dissolution caused by AFM tip scratching was inhibited by adding sodium chromate or dodecylamine into the corrosive solutions, but their inhibition mechanisms are different. The inhibition effect of sodium chromate is due to its oxidation ability to repair the destroyed protection film and the increase of rigidity of metal surface resulted from the formation of oxide film containing Cr elements. On the other hand, the inhibition effect of dodecylamine is due to the organic adsorption film on metal surface to weaken the friction forces between the tip and the sample and to elevate the ionization energy of metal. C 2006 Springer Science + Business Media, Inc.