Author Description

The anodic behaviour of copper, tin, Cu6Sn5, and Cu3Sn was studied in fluosilicate solutions. Copper and tin were found to dissolve freely, whereas the alloys were passivated. Channels or cavities were found to develop on the surfaces of the alloys during their dissolution, and it was postulated that passivation occurred in these depressions by a dissolution-precipitation process. Mechanisms are proposed for the dissolution of copper and tin. The dissolution of the alloys is more complex, one complicating factor being that the stoichiometry of that reaction is slightly different from the stoichiometry of the undissolved material. A number of photomicrographs are given showing the surfaces of the alloys under various conditions.