| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 179531 | Electrochemistry Communications | 2013 | 4 Pages |
A new approach for studying the local distribution of anodic and cathodic sites in a corroding system using the scanning vibrating electrode technique (SVET) and scanning electrochemical microscopy (SECM) is presented. When zinc is coupled to iron, dissolution of the active metal occurs in a localized manner (e.g., pitting corrosion), allowing for cathodic sites to be developed on zinc. Local alkalization and oxygen consumption related to cathodic activity are detected above portions of the zinc surface using SECM. Anionic fluxes related to the generation of OH− ions could be measured on the zinc surface outside the corroding pit by rastering the SVET probe closer to the substrate.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Experimental observation of cathodic activity on the more active metal in a zinc–iron galvanic couple. ► The localized dissolution of zinc from corrosion pits leaves the remaining surface available for oxygen electroreduction. ► Depletion of dissolved oxygen and the alkalization of the electrolyte solution occur around the cathodic sites. ► Changes on the oxygen concentration and the pH in the solution can be spatially resolved using an antimony tip in SECM. ► Fluxes of the OH− anions originating from both metals have been detected by SVET.
