Anodic behaviour of stainless steel covered with an electrochemically deposited Ce2O3–CeO2 film

Investigations have been carried out on the changes in the corrosion behaviour of OC4004 stainless steel protected by an electrochemically deposited Ce2O3–CeO2 film. It may be assumed, on the basis of the obtained results, that in addition to exercising a screening effect, the cerium oxides film plays the role of an effective cathode stabilizing the steel passive state, i.e. its corrosion resistance without changing the zones of potentials where the steel is in a stable passive state. It has been concluded that in the cases when the Ce2O3–CeO2-protected stainless steel will be used as a construction material for catalytic converters designed for purification of nitric acid containing emissions, the corrosion will proceed at potentials, where the steel passive state will not be disturbed. Simultaneously, the presence of the Ce2O3–CeO2 coverage screens the accumulation on the SS/Ce2O3–CeO2 surface of iron/iron oxides and hydroxides, which could have a negative effect (as catalyst poisons), on the desired catalytic process.