PHOTOGRAPHIC EVIDENCE OF DELAMINATION OF 2-LAYER STRUCTURE OF ANODIC OXIDE-FILMS ON TANTALUM FORMED IN ELECTROLYTES CONTAINING PHOSPHATE

Direct photographic evidence of delamination of the two-layer film str ucture for anodic tantalum oxide films formed in phosphate-containing electrolytes has been discovered in scanning electron microscopy photo micrographs of flaws in the anodic oxide. The amorphous dielectric oxi de, whose bi-layer structure was suggested by Vermilyea et al., appear s to have been displaced from the site of crystalline oxide growth and to have undergone layer delamination as a result of the large mechani cal stresses present.