The use of polar organic substances and colloidal materials as corrosion inhibitors has been investigated for many years and wide application has been found for them, especially in acid solutions. In general there is little disagreement that these materials function essentially by treating the metal surface. The first step in the mechanism almost always has been described in terms of adsorption of the inhibitor molecule from solution onto the metal surface. There is, however, considerable variance in opinion as to the function of the adsorbed molecule thereafter in retarding corrosion.
A number of workers postulate that the effect is one which may be described best as a “blanketing” action. Mann and his co-workers1 discuss the amines and certain positively charged colloids in terms of their migration to the cathodic areas of the metal where they become attached, probably by virtue of the electrostatic forces. They maintain that the effectiveness...
