On the use of mercury-coated tips in scanning electrochemical microscopy to investigate galvanic corrosion processes involving zinc and iron

The corrosion processes related to zinc dissolution that take place in an iron–zinc galvanic pair exposed to a chloride solution were investigated by scanning electrochemical microscopy (SECM) using a mercury-coated platinum microelectrode as SECM tip. Both the release of zinc ions and the consumption of dissolved oxygen that occur in separate sites at the iron–zinc galvanic pair were monitored. Zinc ion quantification could be performed by stripping the zinc metal collected at the Hg-coated tip using linear sweep voltammetry.

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► Scanning microelectrochemical investigation of the corrosion of active metals.
► Hg-microelectrode tips for amperometric scanning electrochemical microscopy.
► Detection of Zn(II) ions release in the galvanic corrosion of a Zn–Fe pair.
► Concentration profiles of metal ions determined by stripping voltammetry.