The Early-Stage Corrosion of Copper Materials in Chloride and Sulfide Solutions: Nanoscale Characterization and The Effect of Microstructure. Issue 3 (1st March 2022)

• Record Type: Journal Article
• Authors: Guo, Mengnan; Daub, Kevin; Dong, Qingshan; Long, Fei; Binns, W. Jeffrey; Daymond, Mark R.; Shoesmith, David W.; Noël, James J.; Persaud, Suraj Y.
• Is Part Of: Journal of the Electrochemical Society. Volume 169:Issue 3(2022)
• Publication Date: 2022-03-01
• Subjects: Sulfide-induced corrosion -- Copper -- Nuclear waste disposal -- Electron microscopy -- Nanoscale characterization; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/1945-7111/ac4bf4
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The microstructures of copper (Cu) materials were investigated by electron backscatter diffraction, showing that electrodeposited (ED) Cu has a homogenous polycrystalline microstructure, while cold spray (CS) Cu has a heterogeneous microstructure with varying grain size, pores, and interfacial splat regions. The corrosion rate was examined by corrosion potential (ECORR ) and polarization resistance (Rp ) measurements on Cu specimens in solutions containing 0.1 M NaCl + 1 × 10 −3 M Na2 S. Although the as sprayed CS-Cu was the least corrosion resistant, the corrosion rate of the heat-treated CS-Cu was similar to that of the ED-Cu and wrought Cu (SKB-Cu). Electrochemical behaviours of Cu materials were investigated by either a potentiodynamic scan or a potentiostatic polarization at a more positive potential (E > ECORR ) for various experiment durations up to 4 h, showing that the heat-treated CS-Cu, SKB-Cu and ED-Cu exhibited very similar behaviour while the as sprayed CS-Cu showed erratic behavior consistent with a variable surface reactivity. Nanoscale scanning transmission electron microscopy analysis has been performed at the cross-section of an anodically-oxidized CS-Cu specimen, revealing a two-layer film structure, mostly composed of Cu sulfide, with a minor diffusion of sulfur in the local area of an interfacial splat boundary tip.