The Characteristic and the Evaluation of the Barrier Type Anodic Oxide Film

Mainly with regard to the barrier films on Al and partly on Ta, the influence of pretreatments, forming electrolyte, anodizing conditions and heating in air, water or electrolyte solutions on the leakage current, tan δ, durability for water and acid, transient behaviour and breakdown voltage were reviewed along with the characterization of the film. In conclusion, it is emphasized that the characteristic of the film is not inherent but is so variable as to be markedly influenced by those factors listed above, especially by anion species in the forming electrolyte.