Study of Early Stage Interaction of Oxygen with Al; Methods, Challenges and Difficulties

Aluminum is among the metals with the greatest affinity for oxygen. Aluminum oxidation occurs easily and rapidly; a surface film can be formed in order of milliseconds. Study of initial oxidation is very important as it concerns the first step of a metal's oxidation and corrosion behavior. Characteristics of the kinetics of early-stage oxidation are believed to have an important influence on the later steadystate growth. Modern sophisticated experimental studies such as scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), low energy electron diffractions (LEED), combining ellipsometry and auger electron microscopy have clarified some of the details of initial stage of both oxygen chemisorption and oxidation kinetics of Al. However, the experimental data are not consistent. Furthermore, the dynamics of absorption and oxidation process are much less understood. This paper reviews the methods, techniques and the challenges of Al initial stage oxidation process measurements and also introduces a new method for studying the oxide layer formation using ablation of the surface with an ultra-fast laser beam and fast imaging techniques. © 2011 The Minerals, Metals & Materials Society. All rights reserved.