Investigation of Mg/Al alloy sacrificial anode corrosion with scanning electrochemical microscopy

András Kiss, Ricardo M. Souto, Géza Nagy

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6 Citations (Scopus)

Abstract

Corrosion of Mg/Al alloy was investigated with the scanning electrochemical microscope (SECM) using a Mg2+ion selective microelectrode (ISME) as measuring tip. Mg/Al alloys have practical application as sacrificial anodes to prevent the corrosion of various metals susceptible to corrosion. A typical application of such sacrificial anodes is in water boilers. A model (Mg/Al)/Fe target was fabricated using boiler sacrificial anode and high purity iron wires. Corrosion current was measured between the electrically connected galvanic pair, and Mg2+ion flow rate was calculated with Faraday's law of electrolysis. However, Mg2+flow rate could not be calculated with this method while the twometals were left electrically-disconnected. For this reason, fixed height lateral scans and retreating scans were performed above the Mg2+sample with Mg2+ion-selective electrodes employed as SECM tips. Mg2+flow rate was estimated using the concentration profiles obtained with SECM. Relatively high-speed scans were possible with robust, solid contact Mg2+micropipette electrodes, owing to their low resistance compared to conventional micropipettes of the same size.

Original languageEnglish
Pages (from-to)11-14
Number of pages4
JournalPeriodica Polytechnica Chemical Engineering
Volume57
Issue number1-2
Publication statusPublished - 2013

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Keywords

  • Galvanic corrosion
  • ISME
  • Ion-selective microelectrode
  • Potentiometric tip
  • SECM
  • Scanning Electrochemical Microscope
  • Solid contact

ASJC Scopus subject areas

  • Chemical Engineering(all)

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