Electrochemical properties of protective coatings on maraging steel

摘要

Electrochemical properties of oxides formed on 250 maraging steel in steam at elevated temperatures were compared to standard phosphating treatment. Polarization curves and time-to-pitting experiments established the advantage of these oxides over phosphating. Whereas the elongation of the oxide was low, and diffusion coefficient of hydrogen was not dramatically smaller than for bare maraging steel, the threshold stress in tress corrosion cracking studies was significantly higher for oxidized steel. It is postulated that these benefits arise from the austenitic sub-layer.