The Effect of the Fixed Charge Density of Coating Film on Pitting Potential of Aluminum

Abstract

It has been known well that ion exchange membranes have good resistivity on electrolyte permeation. In this study, the effectiveness of additional ion exchange ability on coating films was examined by pitting potential measurement of coated aluminum specimen. Addition of polyphosphoric acid in acrylic/epoxy resin formed the cation exchange film with the effective fixed charge density value of 2.7×10¹mol/m³. And, it was appeared that the pitting potential of the specimen shifted to noble potential in an aqueous chloride solution at lower concentration than the effective fixed charge density value.