Abstract
The uniform and localized corrosion of Zn in chloride solution were analyzed using the scanning vibrating electrode technique (SVET). Initially, shallow crystallographic pits nucleate, which then spread laterally assuming prismatic hexagonal orientations (100), and finally cover the whole surface. Anomalous cathodic currents are observed by SVET over the whole surface after the corrosion type changes from localized to uniform corrosion of the metal surface due to the lateral growth of pits. These anomalous residual cathodic currents are unreal and were assigned to pH and oxygen concentration variations near the electrode surface, changing the open circuit potential (OCP) of the vibrating Pt microelectrode of the SVET system in the negative direction toward the surface. The combined action of the /Zn2+ hydrolysis and oxygen reduction causes a pH increase toward the metal surface. A similar effect is expected in the case of oxygen depletion near the surface by the cathodic reaction. For a corrosion process under diffusion control, the concentration gradients will form in the region of the μ-electrode vibration, as confirmed by measuring the OCP of the μ-electrode versus the distance to the electrode surface.
Similar content being viewed by others
Data availability
Data will be sent on request.
References
Ogle K, Baudu V, Garrigues L, Philippe X (2000) Localized electrochemical methods applied to cut edge corrosion. J Electrochem Soc 147(10):3654–3660
Fedrizzi L, Bonora P (2007) Organic and inorganic coatings for corrosion prevention: research and experience, Papers from EUROCORR ‘96 CRC Press, London
Jagtap RN, Patil PP, Hassan SZ (2008) Effect of zinc oxide in combating corrosion in zinc-rich primer. Prog Org Coat 63(4):389–394
Gergely A, Bertóti I, Török T, Pfeifer É, Kálmán E (2013) Corrosion protection with zinc-rich epoxy paint coatings embedded with various amounts of highly dispersed polypyrrole-deposited alumina monohydrate particles. Prog Org Coat 76(1):17–32
Manhabosco SM, Manhabosco TM, Geoffroy N, Vignal V, Dick LFP (2018) Corrosion behaviour of galvanized steel studied by electrochemical microprobes applied on low-angle cross sections. Corros Sci 140:379–387
Reeichlek RA, Mccurdy EG, Hepler LG (1975) Zinc hydroxide: solubility product and hydroxy-complex stability constants from 12.5-75 °C. Can J Chem 53(24):3841–3845
Assaf FH, Abd S, El-Rehiem Z (1999) AM Pitting corrosion of zinc in neutral halide solutions. Mater Chem Phys 58(1):58–63
Thomas S, Birbilis N, Venkatraman MS, Cole IS (2012) Corrosion of zinc as a function of pH. Corrosion NACE 015009-1- 015009-9
Miao W, Cole IS, Neufeld AK, Furman S (2007) Pitting corrosion of Zn and Zn-Al coated steels in pH 2 to 12 NaCl solutions. J Electrochem Soc 154(1):C7–C15
Alvarez MGM, Galvele JR (1976) Pitting of high purity Zinc and pitting potential significance. Corrosion NACE 32(7):285–294
Santos AP, Manhabosco SM, Rodrigues JS, Dick LFP (2015) Comparative study of the corrosion behavior of galvanized, galvannealed and Zn55Al coated interstitial free steels. Surf Coat Technol 279:150–160
Manhabosco SM, Batista RJC, Silva SN, Dick LFP (2015) Determination of current maps by SVET of hot-dip galvanized steel under simultaneous straining. Electrochim Acta 168:89–96
Win N, Khan K, Sullivan JH, McMurray HN (2019) Concentration effects on the spatial interaction of corrosion pits occurring on zinc in dilute aqueous sodium chloride. J Electrochem Soc 166:C3028–C3038
Challi MS, Worsley DA (2001) Cut edge corrosion mechanisms in organically coated zinc–aluminium alloy galvanized steels. Br Corros J 36(4):297–303
Souto RM, Garcia YG, Bastos AC, Simões AM (2007) Investigating corrosion processes in the micrometric range: a SVET study of the galvanic corrosion of zinc coupled with iron. Corros Sci 49(12):4568–4580
Izquierdo J, Nagy L, González S, Santana JJ, Nagy G, Souto RM (2013) Resolution of the apparent experimental discrepancies observed between SVET and SECM for the characterization of galvanic corrosion reactions. Electrochem Commun 27:50–53
Assaf FH, Abd El-Rehiem SS, Zakya AM (1999) Pitting corrosion of zinc in neutral halide solutions. Mater Chem Phys 58(1):58–63
Watanabe N, Devanathan MAV (1964) Reversible oxygen electrodes. J Electrochem Soc 211:615–619
Hoare JP (1966) The reversible oxygen electrode. Nature 211(5050):703–705
Burke LD, Buckley DT (1994) Anomalous stability of acid-grown hydrous platinum oxide films in aqueous media. J Electroanal Chem 366(1-2):239–251
Lopes PP, Strmcnik D, Tripkovic D, Connell JG, Stamenkovic V, Marković NM (2016) Relationships between atomic level surface structure and stability/activity of platinum surface atoms in aqueous environments. ACS Catal 6(4):2536–2544
Brown PL, Ekberg (2016) Hydrolysis of metal ions. Wiley-VCH, Weinheim
Snihirova D, Lamaka SV, Gonzalez-Garcia Y, Yilmaz A, Scharnagl N, Montemor MF, Zheludkevich ML (2019) Influence of inhibitor adsorption on readings of microelectrode during SVET measurements. Electrochim Acta 322(134761):1–9
Acknowledgments
The authors much acknowledge the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior for the fellowship of V.C. and Fundação Luiz Englert for the fellowship of N.F.L (Porto Alegre, Brazil). The authors also acknowledge Galvânica Beretta (Nova Santa Rita, Brazil) for providing Zn samples and the Microscopy & Microanalysis Center of UFRGS (CMMA) for the use of facilities.
Funding
This study was financially supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (funding project number CAPES PROEX 23038.000341/2019-71).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Electronic supplementary material
ESM 1
(PDF 1010 kb)
Rights and permissions
About this article
Cite this article
Cerveira, V., Lopes, N.F. & Dick, L.F.P. Anomalous currents determined by SVET due to composition gradients on corroding Zn surfaces in 0.1 M NaCl. J Solid State Electrochem 24, 1889–1898 (2020). https://doi.org/10.1007/s10008-020-04646-7
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10008-020-04646-7