Electron micrographs from thick oxide layers on aluminium

Abstract

Electron micrographs have been obtained of the pore structure in the thick oxide layer formed by anodizing aluminium in sulphuric acid. The pores are shown to be minute tubes of approximately 200 Å diameter running perpendicularly through the oxide and ending almost in contact with the underlying metal. The pore base thickness has been estimated, and the effect of a change in anodizing conditions on the pore base pattern is shown.