Localising the electrochemistry of corrosion fatigue

Self Cite

Scanning electrochemical cell microscopy is a useful technique for determining variations in corrosion behavior across a surface. However, the numerous options for experimental parameters and little understanding of their effect on the corroding system render comparisons of results between studies difficult. Herein, we explore changes in corrosion behavior of two martensitic stainless steels, a cast CA6NM and a wrought S41500, as a result of the chosen experimental parameters, including scan rate, approach potential, surface oil immersion, and tip aperture diameter. The study demonstrates that these experimental parameters can be controlled to probe oxide passivation kinetics and single pitting events by changing the surface state and cathodic currents. We measured the pitting and repassivation kinetics of a single pit and determined the compositional change of the Al 2 O 3 inclusion site initiation point. Hundreds of data points were measured within 17 h of experimental time on the stainless steel samples, allowing statistical averages of corrosion and pitting values. This work will open new avenues for fine-tuning various corrosion aspects at the microscale, thereby contributing to a deeper understanding of the corrosion processes and mechanisms of diverse materials.

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Selective Initiation of Corrosion Pits in Stainless Steel Using Scanning Electrochemical Cell Microscopy

Grandy,

Yassine,

Lacasse

et al. 2024

Self Cite

“…6−9 Local breakdown mechanisms are complicated by the application and residuals of stress. 10 Scanning electrochemical microscopy (SECM) has become a vital technique in corrosion research to measure local reactivity of corroding metals and elucidate local corrosion mechanisms. The technique's high spatial resolution stems from using an ultramicroelectrode (UME).…”

Section: ■ Introductionmentioning

confidence: 99%

“…Oxidation of the world’s metallic infrastructure poses an environmental threat of heavy metal contamination, jeopardizes mechanical integrity and safety of objects, and contradicts sustainability . Many corrosion failure mechanisms stem from localized attack due to microstructural heterogeneities and defects, such as metallic/nonconductive inclusions, grain boundaries, different crystallographic orientations, and dislocations, especially in halide-rich environments. − Local breakdown mechanisms are complicated by the application and residuals of stress …”

Section: Introductionmentioning

confidence: 99%

Effect of Redox Mediators on Corrosion Behavior and Scanning Electrochemical Microscopy Response

Mena-Morcillo,

Ebrahimzadeh Pilehrood,

Moshrefi

et al. 2024

Scanning electrochemical microscopy (SECM) is widely used to measure local electrochemical reactivity of corroding surfaces. A major criticism of using SECM in feedback mode for corrosion studies is the requirement of an external redox mediator (RM) as it could react with the metal and affect the Nernst potential at the metal–solution interface. Consequently, it becomes challenging to differentiate the interference caused by the RM from the local reactivity of the metal. Herein, a multiscale electrochemical approach is presented to investigate the effect of RM choice on the corroding substrate. Two common RMs, ferrocenemethanol and hexaammineruthenium(III) chloride, were used to perform SECM over copper and aluminum. It was found during macroscale electrochemical measurements that Ru(NH)6 3+ acted as an oxidant and promoted corrosion. The SECM feedback behavior varied for copper depending on the RM used, suggesting that the corrosion reactions controlled the negative feedback mechanism, not the formation of an insulating passive film. The passivated aluminum surface consistently exhibited negative feedback, regardless of the RM used. SECM approach curves also displayed a distortion in the steady state current, which was caused by the deposition of substrate-generated species on the microelectrode. These deviations in feedback response were accounted for during analysis through incorporation into a finite element model to accurately extract the RM kinetic rate constants. The importance of understanding these processes is highlighted to avoid misinterpretation of passive behavior and advances toward a more quantitative use of SECM for corrosion studies.

“…Scanning electrochemical cell microscopy (SECCM), as a member of scanning probe microscopy (SPM) techniques, has been widely applied in various fields such as catalysis, − energy storage materials, , electrochemical imaging, , metal corrosion, − lithium batteries, and localized surface modification , since its development in 2010. Its notable technical advantage lies in miniaturizing the dual-electrode/triple-electrode test system of conventional electrochemical methods into a micropipette probe with a tip diameter ranging from hundreds of nanometers to a few micrometers, enabling the characterization of electrochemical behavior in the localized areas of the substrate of interest .…”

mentioning

confidence: 99%

Microscale Corrosion Inhibition Behavior of Four Corrosion Inhibitors (BTA, MBI, MBT, and MBO) on Archeological Silver Artifacts Based on Scanning Electrochemical Cell Microscopy

Sun,

Liu,

et al. 2023

The problem of corrosion-induced discoloration and embrittlement in silverware is a significant concern for the long-term preservation of excavated archeological silver artifacts, even after thermal restoration. The key to addressing this issue lies in the meticulous selection and evaluation of corrosion inhibitors that possess targeted corrosion inhibition capabilities. This study focuses on the evaluation of corrosion inhibitors for archeological silver artifacts using scanning electrochemical cell microscopy (SECCM) and X-ray photoelectron spectroscopy (XPS). The researchers aimed to compare the inhibition effects of four corrosion inhibitors [1,2,3-benzotriazole (BTA), 2-mercaptobenzimidazole (MBI), 2-mercaptobenzothiazole (MBT), and 2-mercaptobenzoxazole (MBO)] on a simulated Ag–Cu alloy sample and understand their mechanisms. The results showed that MBT exhibited better corrosion inhibition for microstructural regions with higher silver content due to its ability to form stable chelation structures with Ag(I). MBO exhibited better corrosion inhibition for microstructural regions with higher copper content due to its strong affinity with Cu(I). The targeted corrosion inhibition ability for the β-phase was ranked as MBO > BTA ≈ MBI > MBT, while for the α-phase the ranking was MBT > MBO > MBI > BTA. The study demonstrated the feasibility and capabilities of SECCM in the targeted screening of corrosion inhibitors for different compositions and microstructural regions in archeological metal artifacts. This study highlights the potential of SECCM in corrosion inhibitor research for archeological metal artifacts and wider applications in metal material corrosion protection.