Corrosion Considerations.

The etching of metals in the graphic arts is a corrosion process. This paper presents in a simplified manner the fundamental mechanisms of corrosion including the electrochemical theory of corrosion. This is the established and accepted theory. Why metals corrode or do not corrode is included. The effect of impressed currents (electrolytic etching) on corrosion is described. A brief discussion is given of the surface characteristics of metals, with regard to accepting or rejecting electroplated metal. The corrosion characteristics of the metals zinc, copper, nickel, chromium, aluminum and magnesium and of the etchants nitric acid and ferric chloride are described. As far as this paper is concerned, these metals and corrosive media cover most of the materials of construction for handling pertinent acids and chemicals. (No manuscript of Dr. Fontana's paper was submitted.)