Investigation of the effects of the magnetic field on the anodic dissolution of alloy 690 in SO4 2- + SCN- solution using digital holography

Dongling Xu; Chen Sang; Boyu Yuan; Liang Li

doi:10.1016/j.heliyon.2023.e13566

Investigation of the effects of the magnetic field on the anodic dissolution of alloy 690 in SO₄ ^2- + SCN^- solution using digital holography

Heliyon. 2023 Feb 9;9(2):e13566. doi: 10.1016/j.heliyon.2023.e13566. eCollection 2023 Feb.

Authors

Dongling Xu¹, Chen Sang², Boyu Yuan², Liang Li¹

Affiliations

¹ Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou, 221116, China.
² Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, 221116, China.

Abstract

Digital holography has been employed for in situ observation of dynamic processes occurring at the electrode|electrolyte interface during the anodic dissolution of Alloy 690 in solutions containing SO₄ ^2- + SCN^- with or without magnetic field (MF). It was found that MF increased the anodic current of Alloy 690 in 0.5 M Na₂SO₄ + 5 mM KSCN solution but showed a decreased value when evaluated in 0.5 M H₂SO₄ + 5 mM KSCN solution. For each solution, as a result of the stirring effect due to Lorentz force, MF showed a decreased localized damage further preventing pitting corrosion. The content of nickel and iron at grain boundaries is higher than that on the grain body, in accordance with the Cr-depletion theory. MF increased the anodic dissolution of nickel and iron, which in turn increased the anodic dissolution at grain boundaries. In situ inline digital holography revealed that IGC begins at one grain boundary and progresses to adjacent grain boundaries with or without MF.

Keywords: Alloy 690; Anodic dissolution; Digital holography; Magnetic field; SO42− + SCN−.