Kinetic Studies on the Dissolution Behavior of Anodic Oxide Films on Aluminum in KF Solutions

A study was made to account for the dissolution of naturally developed and anodically formed oxide films on aluminum in KF solutions. The behavior of these oxide films was investigated by impedance and potential measurements. In general, oxide dissolution was found to follow the empirical relation where $Cm−1$ is proportional to the oxide film thickness. The rate of the dissolution process changed, as indicated by the change in the value of B. This behavior indicates that the oxide is of a duplex nature; the inner layer undergoes dissolution more freely than the outer layer. The oxide dissolves at a rate independent of its thickness, i.e, following zero-order kinetics.