IN-SITU ATOMIC-FORCE MICROSCOPY, IMAGING OF ELECTROPRECIPITATED NICKEL HYDROUS OXIDE-FILMS IN ALKALINE ELECTROLYTES

In situ atomic force microscopy images of nickel hydrous oxide films e lectrodeposited on the basal plane of highly oriented pyrolytic graphi te in alkaline electrolytes have shown that a stepwise oxidation leads to irreversible formation of wide crevices throughout the material. U pon subsequent stepwise reduction, the gaps close leaving a hairline t ype crack which follows the profile of the crevice. These potential in duced structural rearrangements have been attributed to stresses induc ed by differences in the densities of the nickel hydrous oxide in the two oxidation states.