Abstract
Copper and copper-nickel alloys are known to form partially passive films in marine conditions, both naturally and under positive potential bias. Here, the anodic passivation behaviour of copper and of constantan (Cu54Ni45Mn1) as a model for a copper-nickel alloy are investigated and compared at high positive overpotentials and in 0.5 M NaCl(aq). Abrupt potential-dependent passive film breakdown is observed for both Cu and Cu-Ni alloys during voltammetry and during chrono-amperometry experiments. For Cu a single transitions occurs at 0.2 V vs. SCE consistent with a Cu(II/I) process leading to interfacial stress and breaking of a passive CuCl film. For Cu-Ni alloy, two stages are observed at 0.3 V vs. SCE due to a Cu(II/I) process and at 1.7 V vs. SCE due to a sub-interfacial Ni(IV/II) process. A breakdown mechanism is proposed based on redox processes at the buried interface at the metallic conductor | passive ion conductor junction.
| Original language | English |
|---|---|
| Pages (from-to) | 195-200 |
| Number of pages | 6 |
| Journal | ChemElectroChem |
| Volume | 7 |
| Issue number | 1 |
| Early online date | 13 Dec 2019 |
| DOIs | |
| Publication status | Published - 2 Jan 2020 |
Bibliographical note
Funding Information:We thank members of the Department of Chemistry and the Materials Analysis Suite (MC2) at the University of Bath for ongoing support and access to facilities.
Publisher Copyright:
© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Keywords
- Cu−Ni
- alloys
- anodic passivation
- breakdown
- marine corrosion
ASJC Scopus subject areas
- Catalysis
- Electrochemistry
Access to Document
- CuNi_Alloy_ChemElectroChem_Template_revision_final
This is the peer reviewed version of the following article: Marken, F., Langley, A., Elmer, A. and Fletcher, P. (2019), Linking the Cu(II/I) and the Ni(IV/II) potential to passive film breakdown for a Cu‐Ni alloy immersed in aqueous 0.5 M NaCl. ChemElectroChem, which has been published in final form at https://doi.org/10.1002/celc.201901927. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.