Autodeposition of organic coatings on metal surfaces is used for corrosion prevention in many branches of industry. The main advantages are its simplicity, ease of operation, low energy costs, and no volatile organic compounds. Furthermore the thickness of the coating is uniform regardless of the sample's shape. The autodeposition process consists of cleaning the metal surface, water rinsing, coating in the autodeposition bath, water rinsing, and curing. The coating process is due to multivalent metal ions produced by the oxidation of the metal surface, which destabilize the dispersion polymer particles. Typically an autodeposition bath consists of an acidic water emulsion of a polymer, to which an oxidant, a complexing agent, and an emulsifier are added. The oxidant is usually hydrogen peroxide. It is of considerable interest to know how different parameters influence the corrosion resistance of the coatings. New emulsifiers and coating materials have been proposed to improve the quality of the protective films. Other investigators have studied the effect of the production conditions on the corrosion resistance. In this work the type of the latex and the nature and the concentration of the acid are studied. The corrosion resistance of the coatings is used to characterize their quality.
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