XPS Investigation of Anodic Passive Films on Fe60Ni40 Polycrystalline Alloy

Anodic passive films formed on Fe60Ni40 in H3BO3-Na2B4O7 buffer solution (pH-9.20) and in H3PO4-Na2HPO4, buffer solution (pH-7.41) have been investigated by XPS. By analysis of the chemical states of elements, components and structure of films, we have probed into the mechanism of the formation of the anodic passive. films. In the H3HO3-Na2B4O7 buffer solution (pH-9.20), the formation of passive film was controlled. by adsorption of OH, and the growth of the passive film was a function of passivation potential and time in passive range. The duplex structure, the Fe, Xi/FeO3, NiO/FeOOH, Ni(OH)(2) was confirmed by detailed peak analysis and profiling. In H3PO4 Na2HPO4 buffer solution (pH=7.41), the formation of passive fain was controlled by competitive react, that is cations of anodic dissolution reacted with anions Such as PO43 and OH et al in solution to form compacted deposit films of the phosphate phase.