AN AES STUDY OF ANODIC OXIDE FILM ON 1Cr18Ni9 STAINLESS STEEL

The AES has been used to study the composition of the anodic oxide film on 1Cr18Ni9 stainless steel. The film was formed in the transpassive region during the constant potential anodic polarization in H_2SO_4 and after a treatment with Na_2MoO_4. It has been found that the outer layer of the film contains a lot of Mo and the middle layer is rich in Cr. The concentration of oxygen in the rest of the layer up to the interface rapidly reduces to zero. The middle layer in the transpassive anodic oxide film which is rich in Cr is more wider and oxidized more complete than that in HNO_3 oxide film. By comparison with other oxide films, the possible mechanisms for passivation of transpassive anodic polarization are discussed.