Profiles of defects in anodic oxide films deduced from dissolution studies

Abstract

From studies of the chemical dissolution of anodic oxide films on several valve metals, the relative concentration profiles of atomic defects across the films have been deduced. Oxides that are characterized by low energies of defect formation contain relatively high concentrations of defects, this concentration increasing as the oxide grows. Films that are characterized by intermediate energies of defect formation contain lower concentrations of defects, which decrease as the oxide grows, while those oxides that are characterized by high energies of defect formation contain low concentrations of defects, which decrease only insignificantly as the oxide grows. Respective examples of each type are tungsten oxide, titanium oxide, and hafnium oxide.