A comparision between the oxygen reduction rates on zinc in the active and passive state

S. Thomas, I S Cole, N. Birbilis

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

Abstract

The oxygen consumption by zinc, due to the oxygen reduction reaction (ORR), was measured using a Pt microelectrode, operating in a redox completion mode. These experiments were performed on zinc anodically polarised, in solutions with pH 7 (active state) and pH 13 (passive state). In the electrode potential range -1.05 VSCE to -0.5 VSCE, the anodic currents in the pH 7 solution (range: 2.5-7.5 mA/cm2) are higher than that in a pH 13 solution (range: 0.01 to 0.5 mA/cm2). In the pH 7 solution, when anodically polarised, the oxygen concentration measured (using the Pt microelectrode) at a 50 micron distance from the zinc surface is 15-60% of the bulk oxygen concentration. Therefore at the same position, the oxygen consumption by zinc (due to ORR), is between 40-85% of the bulk oxygen concentration. In a pH 13 solution, as zinc becomes passive, the oxygen consumption by zinc (due to ORR) is around 70-80% of the bulk oxygen concentration. The rate of ORR on zinc oxides (ZnO/Zn(OH)2) is therefore significant when compared to actively corroding zinc.

Original languageEnglish
Title of host publicationAnnual Conference of the Australasian Corrosion Association 2013: Corrosion and Prevention 2013
Subtitle of host publicationBrisbane, Australia; 10-13 November 2013
Place of PublicationKerrimuir VIC Australia
PublisherAustralasian Corrosion Association (ACA)
Pages689-696
Number of pages8
ISBN (Electronic)9781634394369
Publication statusPublished - 2013
EventAustralasian Corrosion Association (ACA) Conference 2013: Corrosion and Prevention - Brisbane Qld Australia, Brisbane, Australia
Duration: 10 Nov 201313 Nov 2013

Conference

ConferenceAustralasian Corrosion Association (ACA) Conference 2013
Abbreviated titleCP 2013
CountryAustralia
CityBrisbane
Period10/11/1313/11/13

Keywords

  • Oxygen reduction reaction
  • Passivity
  • Pt microelectrode
  • SECM
  • Zinc

Cite this

Thomas, S., Cole, I. S., & Birbilis, N. (2013). A comparision between the oxygen reduction rates on zinc in the active and passive state. In Annual Conference of the Australasian Corrosion Association 2013: Corrosion and Prevention 2013: Brisbane, Australia; 10-13 November 2013 (pp. 689-696). [120] Australasian Corrosion Association (ACA).