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Electrochemical corrosion resistance of thermal oxide formed on anodized stainless steel

Hongda Deng (Department of Chongqing University of Science and Technology, School of Metallurgical and Materials Engineering, Chongqing, China)
Yongliang Liu (Department of Northeast Sichuan Gas Field, PetroChina Southwest Oil and Gas Field Company, Chengdu, China)
Zhen He (Chongqing Acoustics-Optics-Electronics CO., LTD. of China Electronics Technology Group Corporation, Chongqing, China)
Xiantao Gou (Chongqing University of Science and Technology, Chongqing, China)
Yefan Sheng (Chongqing University of Science and Technology, Chongqing, China)
Long Chen (Chongqing University of Science and Technology, Chongqing, China)
Jianbing Ren (Chongqing Liyun Nozzle Limited Company, Chongqing, China)

Anti-Corrosion Methods and Materials

ISSN: 0003-5599

Article publication date: 9 April 2021

Issue publication date: 25 May 2021

114

Abstract

Purpose

The purpose of this paper is to investigate and explain thermal oxide effect on electrochemical corrosion resistance anodized stainless steel (SS).

Design/methodology/approach

Electrochemical corrosion resistance of thermal oxides produced on anodized 304 SS in air at 350°C, 550°C, 750°C and 950°C in 3.5 wt.% NaCl solution have been investigated by dynamic potential polarization, EIS and double-loop dynamic polarization. Anodized 304 SS were obtained by anodization at the constant density of 1.4 mA.cm-2 in the solution containing 28.0 g.L-1H3PO4, 20.0 g.L-1C6H8O7, 200.0 g.L-1H2O2 at 70°C for 50 min. SEM and EDS had been also used to characterize the thermal oxides and passive oxide.

Findings

Interestingly, anodized 304SS with thermal oxide produced at 350°C displayed more electrochemical corrosion and pitting resistance than anodized 304 SS only with passive oxide, as related to the formation of oxide film with higher chromium to iron ratio. Whereas, anodized 304SS with thermal oxide formed at 950°C shows the worse electrochemical corrosion and pitting resistance among those formed at the high temperatures due to thermal oxide with least compact.

Originality/value

When thermally oxidized in the range of 350°C–950°C, electrochemical corrosion and pitting corrosion resistance of anodized 304 SS decrease with the increase of temperature due to less compactness, more defects of thermal oxide.

Keywords

Acknowledgements

The authors would like to acknowledge the financials supported by Natural Science Foundation Project of CQ CSTC (cstc2019jcyj-msxmX0181) and Research Foundation of Chongqing University of Science & Technology (CK2016Z09) and Research Foundation of Chongqing Liyun Nozzle CO., LTD.

Citation

Deng, H., Liu, Y., He, Z., Gou, X., Sheng, Y., Chen, L. and Ren, J. (2021), "Electrochemical corrosion resistance of thermal oxide formed on anodized stainless steel", Anti-Corrosion Methods and Materials, Vol. 68 No. 2, pp. 105-112. https://doi.org/10.1108/ACMM-10-2020-2385

Publisher

:

Emerald Publishing Limited

Copyright © 2021, Emerald Publishing Limited

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