Multi-barrel electrodes containing an internal micro-reference for the improved visualization of galvanic corrosion processes in magnesium-based materials using potentiometric scanning electrochemical microscopy

Dániel Filotás, Bibiana María Fernández-Pérez, L. Nagy, G. Nagy, Ricardo M. Souto

Research output: Contribution to journalArticle

1 Citation (Scopus)


Simultaneous monitoring of pH and Mg2+ distributions above AZ63 magnesium alloy, either spontaneously corroding or galvanically coupled with iron, was achieved using SECM in the potentiometric operation. By introducing an internal micro-reference electrode in a multi-barrel arrangement of the ion-selective microelectrode used as scanning probe, superior performance was achieved compared to conventional single-barrel and double-barrel assemblies. In this way, the impact of the overestimated acidification accompanying metal dissolution using conventional tips was established from model experiments using non ion-sensitive open micropipettes and pH antimony microelectrodes. It is shown that the simultaneously acquired pH and pMg maps provide complementary information on the spontaneous and galvanic corrosion of AZ63 magnesium alloy.

Original languageEnglish
Article number126625
JournalSensors and Actuators, B: Chemical
Publication statusPublished - Oct 1 2019



  • Galvanic corrosion
  • Ion selective microelectrode
  • Magnesium
  • Mg dissolution
  • pH distribution
  • SECM

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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