Spectroscopic investigations of porous and sealed anodic alumina films

Porous anodic alumina films grown in sulfuric acid and similar specimens sealed in nickel acetate and dichromate sealing baths were subjected to a number of surface and bulk analytical techniques (XPS, RBS, SIMS, and XRD). All the oxide films were found to be amorphous-like in nature, to contain significant amounts of H, and have a S content of 1.5-3 atomic percent (a/o) uniformly distributed throughout the oxide matrices. For the sealed oxide films, surface enrichment of Ni and Cr species was observed, being particularly significant in the case of Ni. Uniform bulk concentrations for Ni and Cr were found to be of the order of 0.5 and 1 a/o, respectively. The S, Ni, and Cr species present in the oxide films were identified as sulfate-like, nickel hydroxide and dichromate-like in nature. Ion beam-induced reduction of incorporated S, Ni, Cr, and C species was observed.