Effect of a Thin Oxide Film on the Reaction of Iodine Vapour with Copper

Abstract

IN experimental work on the oxidation of metals the preparation of specimens is directed to the removal of contaminants such as grease, the production of a consistently smooth or rough surface and the realization of a stable metallurgical structure defined by the grain size and texture. The congenital thin oxide film, which may increase in thickness on abrasion and polishing, or change in identity on electrolytic treatment, or disperse on heat-treatment in vacuo, is recognized as influencing the extent of the subsequent oxidation, but is largely ignored in discussions of the oxidation mechanism. In cases where the gaseous reactant is not oxygen, the thin oxide film, having no identity with the reaction system, assumes a different significance. Intuitively this is thought of in terms of protection and some results obtained in a preliminary study of the reaction between copper and iodine vapour demonstrate this.