open access

https://hdl.handle.net/2115/62190

Aging of Passive Oxide on SUS304 Stainless Steel in a Sulfuric Acid Solution

英語

SUS304

2016

The Electrochemical Society

J. Electrochemical Society

163(8)

C459-C469

The passive oxide film on SUS 304 stainless steel (SS) was studied in a 0.1 mol dm−3 sulfuric acid solution as a function of passivation time. The passive oxide films were measured by ellipsometry and X-ray photoelectron spectroscopy (XPS). A Mott-Schottky plot of the film capacitance was employed to determine the donor density in the n-type semiconducting oxide film, and current measurements of the Fe3+/Fe2+ redox couple were employed to investigate the electronic transfer process on the passive oxide film. The passive oxide consists of Cr-Fe-Ni oxides in which enrichment of Cr to 57 mol% occurs as the potential increases. During the aging of the passive oxide at 0.6 V vs. Ag/AgCl/saturated KCl (SSC) for 43 ks, the current decreased from 30 μA cm−2 at 10 s to 0.025 μA cm−2 at 43 ks, and the Cr ratio in the oxide increased from 49 to 57 mol% with an increase in the O2– ratio. Notably, the film thickness remained nearly constant at 1.3 nm during the aging process. Enrichment of the Cr content resulted in a decrease in the donor density of the n-type semiconducting passive oxide and the inhibition of electronic charge transfer from/to the Fe3+/Fe2+ redox couple in the electrolyte.

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Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International

© The Electrochemical Society, Inc. 2016. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published in J. Electrochem. Soc. 2016 volume 163, issue 8, C459-C469 .

0013-4651

1945-7111