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Mesoscopic transformation at initial corrosion stage of 20# steel in aqueous solution under gas–liquid two-phase stratified flow condition

Guirong Yang (Lanzhou University of Technology, Lanzhou, China)
Zhaoxia Pan (Lanzhou University of Technology, Lanzhou, China)
Zhenghai Zhang (Lanzhou University of Technology, Lanzhou, China)
Wenming Song (Lanpec Technologies Limited, Lanzhou, China)
Ying Ma (Lanzhou University of Technology, Lanzhou, China)
Yuan Hao (Lanzhou University of Technology, Lanzhou, China)

Anti-Corrosion Methods and Materials

ISSN: 0003-5599

Article publication date: 29 March 2021

Issue publication date: 25 May 2021

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Abstract

Purpose

This study aims to investigate the initial corrosion behavior in aqueous solution of 20# seamless steel under (CO2/aqueous solution) gas–liquid two-phase stratified flow conditions.

Design/methodology/approach

The initial corrosion behavior was studied through the weight loss methods, scanning electron microscopy with energy-dispersive x-ray spectroscopy and x-ray diffraction.

Findings

The corrosion rate of 20# steel obviously increases with the increasing gas pressure at different corrosion time when the CO2 pressure is less than 0.11 MPa, and the increase of corrosion rate tends to be steady when the pressure exceeds 0.11 MPa. With the increase of CO2 pressure, the corrosion products changed from flocculent to acicular, granular and scaly. A four-stage model for the growth of the corrosion product layer was proposed, namely, the diffusion reaction stage, the local film formation stage, the complete film formation stage and the densification stage of the product film.

Originality/value

A four-stage model for the growth of the corrosion product layer on the pipe wall surface under this condition was proposed, namely, the diffusion reaction stage, the local film formation stage, the complete film formation stage and the densification stage of the product film. The growing process and densification mechanism of corrosion products layer were discussed.

Keywords

Acknowledgements

The authors would like to acknowledge the financial support for this research provided by the National Natural Science Foundation of China (Grant No. 51765035).

Citation

Yang, G., Pan, Z., Zhang, Z., Song, W., Ma, Y. and Hao, Y. (2021), "Mesoscopic transformation at initial corrosion stage of 20# steel in aqueous solution under gas–liquid two-phase stratified flow condition", Anti-Corrosion Methods and Materials, Vol. 68 No. 2, pp. 53-63. https://doi.org/10.1108/ACMM-02-2020-2257

Publisher

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Emerald Publishing Limited

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