(v15preprint32)EIS Monitoring of Electrochemical Behavior of 304L Stainless Steel during Immersion in a diluted Nitric Acid Solution

摘要

The passivation behavior of 304L stainless steel coupons in 5.0M HNO3 was studied electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The electrical properties and compositional changes in the passive film with respect to immersion time are investigated by means of these two techniques.EIS tests show progressive changes related to the formation and growth of a passive layer. An increase of resistance and decrease of capacitance values was observed when immersion time was extended. XPS spectra show that the passive layer is enriched in Cr oxide accompanied by the selective dissolution of Fe oxide with an increase in exposure time in the nitric acid solution.