lncorporation of lons in Anodic Oxide Films on Zirconium and Their Effect on Film Behavior

Abstract

Transmission spectra of anodically formed films show that certain anions such as phosphate, sulfate, and several carboxylates are incorporated in these films when they are formed in solutions containing these ions. Furthermore, hydrous films result from anodizing in strongly oxidizing electrolytes. Films formed in many other solutions contain no incorporated ions. Film conductivity and thickness measurements indicate that incorporated ions increase the electrical resistance of the films, as well as limit their growth. It is suggested that these effects arise from lowered rates of diffusion of electrons and oxygen ions through the films and that the lowered diffusion rates result from the space charge created by the incorporated ions.