Crevice Corrosion Behavior of Alloy 690 in High-Temperature Aerated Chloride Solution

Fangqiang Ning; Jibo Tan; Ziyu Zhang; Xiang Wang; Xinqiang Wu; En-Hou Han; Wei Ke

doi:10.3390/ma15155434

Materials (Aug 2022)

Crevice Corrosion Behavior of Alloy 690 in High-Temperature Aerated Chloride Solution

Fangqiang Ning,
Jibo Tan,
Ziyu Zhang,
Xiang Wang,
Xinqiang Wu,
En-Hou Han,
Wei Ke

Affiliations

Fangqiang Ning: CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Jibo Tan: CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Ziyu Zhang: CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Xiang Wang: CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Xinqiang Wu: CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
En-Hou Han: CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
Wei Ke: CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China

DOI: https://doi.org/10.3390/ma15155434
Journal volume & issue: Vol. 15, no. 15
p. 5434

Abstract

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Crevice corrosion behavior of Alloy 690 in high-temperature aerated chloride solution was studied using a self-designed crevice device. The SEM, EDS, XRD, and XPS analyses results indicated that the oxide films outside the crevice consisted of Ni-Cr oxides containing a small amount of hydroxides, and the oxide films on crevice mouth consisted of a (Ni,Fe)(Fe,Cr)2O4 spinel oxides outer layer and a Cr(OH)3 inner layer, and the oxide films inside the crevice consisted of a α-CrOOH outer layer and a Cr(OH)3 inner layer. When crevice corrosion occurred, the hydrolysis of Cr3+ led to the formation of Cr(OH)3 inside the crevice, and caused the pH value of crevice solution to decrease, and Cl− migrated from outside the crevice into inside the crevice due to electrical neutrality principle and accumulation. When the water chemistry inside the crevice reached the critical value of active dissolution of metal, the active dissolution of metal inside the crevice occurred. In addition, (Ni,Fe)(Fe,Cr)2O4 spinel oxides on the crevice mouth were formed by the deposition of metal ions migrated from inside the crevice. The mechanism of crevice corrosion and the formation mechanism of oxide films at different regions were also discussed.

Published in Materials

ISSN: 1996-1944 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering; Technology: Engineering (General). Civil engineering (General); Science: Natural history (General): Microscopy; Science: Physics: Descriptive and experimental mechanics
Website: http://www.mdpi.com/journal/materials/

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