Structural ordering in annealed anodic oxide films on aluminium

Abstract

Structural ordering in annealed anodic oxide films on aluminium has been investigated by microdiffraction. Microdiffraction, allied with the specimen preparation technique of ultramicrotomy, enables the diffraction patterns to be extracted from exceedingly small volumes, about 10³ nm³, of film material. From this approach, it has been found for the first time that relatively low-temperature annealing of the amorphous anodic oxide films on aluminium results in the development of microcrystalline regions which are too fine to be detected by the conventional X-ray or electron diffraction. The effect of structural ordering on the ionic conductivity in the annealed anodic oxide is also considered.