Studies on the Inhibition of Corrosion of Mild Steel (Part 3)

Abstract

To confirm the idea described in previous reports, some experiments have been carried on as follows.
(1) Corrosion rate of mild steel in hydrochroric, phosphoric, or sulfuric acid was measured, either with the addition of alcoholic compound singly, or with the addition of alcoholic compound in combination with sulfur or nitrogen containing inhibitors, or with the addition of alcoholic compound with chromate for the purpose of preventing pitting corrosion.
(2) In the case of phosphate film on mild steel, the character of film and the speed of film formation were measured with the addition of nitrate to the solution.
(3) Corrosion rate of mild steel dipped in industrial water or sea water with the addition of ordinary inhibitors was measured.
It became clear that the idea expressed in previous reports is applicable to wide range by this experiments. And a new idea about pitting corrosion is inferred as follows: -
Probably a kind of electric condenser is constructed due to adsorptive films, and energies to be accumulated in the condenser will be transported to iron surface through the small holes in the films.
Pitting corrosion occures at the bottom surface of these small holes.