Investigation of Inhibiting Properties Of the Pertechnetate Ion

Abstract

Abstract Corrosion of iron in an aggressive medium containing sulfate and chloride ions has been completely inhibited by addition of minute amounts of the pertechnetate ion. Its effectiveness on the basis of mol concentration required under similar conditions is much greater than that of such widely-used inhibitors as the nitrite, chromate and dichromate ions. The pertechnetate ion is capable of inhibiting corrosion caused by a mol concentration of aggressive ions higher than that of the inhibitor itself. Experimental results indicate that the corrosion inhibiting power of the pertechnetate ion is the result of its adsorption on the metal surface, with resultant stifling of the anodic process of metal ionization. This is accomplished with a quantity of pertechnetate considerably smaller than that needed to produce a monomolecular layer on the metal surface; complete surface coverage is not required for complete inhibition.