Studies of the Structure of Anodic Oxide Films on Aluminum, I

The influence of the formation voltage on the structure of nonporous anodic aluminum oxide films has been studied by electron microscope and electron diffraction methods. It has been shown that low formation voltages (<100 v) produce an amorphous oxide layer, whereas high formation voltages produce amorphous oxide together with some crystalline γ'‐alumina. The location of this crystalline oxide within the anodic layer is discussed.