About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
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| Symposium
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Cutting-Edge Characterization and Electrochemical Techniques for Unraveling Corrosion Phenomena
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| Presentation Title |
Revisiting Transpassivity with a new lens: Transpassive corrosion mechanisms in Ni probed with in situ respirometry coupled electrochemical polarization |
| Author(s) |
Karthikeyan Hariharan, Ann-Kathrin Bach, Mark P. Bruns, Sannakaisa Virtanen |
| On-Site Speaker (Planned) |
Karthikeyan Hariharan |
| Abstract Scope |
Transpassivity in passive metals and alloys has been extensively studied, but unresolved mechanistic questions remain. The complexity of the transpassive regime, influenced by side reactions like oxygen evolution(OER) and secondary passivity, hinders a comprehensive understanding. However, recent development of in situ methods enable simultaneous tracking of all reactions in the transpassive regime, providing a holistic perspective. In this study, we investigate transpassivity of pure Ni in 0.5 M Na<sub>2</sub>SO<sub>4</sub> at pH = 5 coupling conventional electrochemical measurements with novel in situ respirometry technique. Conventional understanding of transpassivity in Ni assumes that dissolution is triggered by OER-induced acidification. On contrary, we provide direct evidence that transpassive dissolution precedes the onset of OER. The OER does not activate until a secondary passive film is formed. While OER-induced acidification did not trigger the Ni transpassive dissolution, it leads to localized intergranular attack. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Environmental Effects, Characterization, Sustainability |