Spectroscopic Investigations of Porous and Sealed Anodic Alumina Films

Porous anodic alumina films grown in sulfuric acid and similar specimens ealed 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- l ike in nature, to contain significant amounts of H, and have a S content of 1.5-3 atomic percent (a/o) uniformly distr ibuted throughout the oxide matrices. For the sealed oxide films, surface enr ichment of Ni and Cr species was observed, being particularly significant in the case of Ni. Uni form bulk concentrat ions 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 identif ied as sulfate-like, nickel hydroxide and dichromate-l ike in nature. Ion beam-induced reduction of incorporated S, Ni, Cr, and C species was observed. Electrochemical ly oxidized A1 has encountered great commercia l exploitation, not only as a material of con-struction in industrial applications, but also in the fabrica-t ion of electronic components. This is largely due to the unique oxide film growth patterns exhibited by the metal in various aqueous-based electrolytes (1). The type o