The Photogalvanic Disruption of Cuprous Oxide Films on Copper

The cuprous oxide film normally present on copper is disrupted by photogalvanic action. Partial illumination of an oxidized copper surface in an electrolyte results in reduction of the cuprous oxide to metallic copper in the illuminated areas and oxidation and dissolution of the cuprous oxide in the unilluminated areas. The disrupted film is believed to lead to an observed increase in corrosion rate of copper in an illuminated salt‐spray cabinet.