Development of Mg2+ ion-selective microelectrodes for potentiometric scanning electrochemical microscopy monitoring of galvanic corrosion processes

Javier Izquierdo, András Kiss, Juan José Santana, Lívia Nagy, István Bitter, Hugh S. Isaacs, Géza Nagy, Ricardo M. Souto

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33 Citations (Scopus)

Abstract

The fabrication of a solid-contact, micropipette-based magnesium ion-selective micro-tipped electrode (ISME) suitable for scanning electrochemical microscopy is reported and compared against a conventional micro-tipped ISME having a conventional aqueous internal reference electrode. Measurements showed that the solid-contact ISME had a lower internal resistance and a faster response time than the one with a liquid-contact. These advantages increased the spatial distribution and improved 2D images depicting concentration distributions of Mg2+. The ability of the microelectrode to image local ionic concentration has been tested over magnesium surfaces freely corroding or galvanically coupled to iron in aqueous chloride-containing solution. Scans of magnesium ion distribution, in the absence of corrosion currents, were alsomade over a micro-pipette source containing a concentrated magnesium chloride gel as a source of Mg2+ and over a current source in the absence of Mg2+. From these measurements it was concluded that the potentiometric measurements over corroding surfaces were dominated by the changes in Mg2+ distributions with small electric potential contributions due to corrosion current.

Original languageEnglish
Pages (from-to)C451-C459
JournalJournal of the Electrochemical Society
Volume160
Issue number9
DOIs
Publication statusPublished - Aug 20 2013

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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