The Use of Nuclear Reactions to Trace the Source of Oxygen in Anodization

In cases where the anodization of metals involves the use of chemical solutions, the oxidation mechanism is frequently uncertain. In such cases it is usually possible to make oxygen bearing solutes from oxygen which is enriched in isotope-18. After use in anodization, the oxide films can be analyzed by the method of nuclear microanalysis which separately profiles the 18O and 16O. In this way the depth distribution of the 18O can be compared quantitatively with that of the 16O arising from all other oxygen bearing chemicals in solution. We have applied this method to the case of the anodization of vanadium and zirconium. The results indicate an unconventional anodization mechanism for the vanadium case.