In-situ impedence spectroscopy study of electrical conductivity and ionic transport in thermally grown oxide scales on a commercial FeCrA1 alloy
2007 (English)In: Oxidation of Metals, ISSN 0030-770X, E-ISSN 1573-4889, Vol. 68, no 5-6, 253-269 p.Article in journal (Refereed) Published
In-situ impedance-spectroscopy measurements were performed at temperatures between 600 and 1,000 degrees C to investigate ionic transport in oxide scales formed on Kanthal AF alloy. The samples were pre-oxidized at 800, 900 and 1,000 degrees C in air. The impedance spectra of the oxide formed at 1,000 degrees C exhibited essentially one semicircle, whereas samples oxidized at lower temperatures showed an additional semicircle at high frequencies suggesting a more heterogeneous oxide. The ionic-transference number, derived by measuring the voltage across the oxide scale, indicates that the oxide is a predominant electronic conductor. Ionic diffusivity in the oxide scales formed at different pre-oxidizing temperatures was calculated, using the ionic-transference number. The ionic diffusivities obtained in this way are in reasonable agreement with literature data acquired by other methods. The oxide-formation temperature has a significant influence on the conductivity and ionic-transport properties of the oxide scale.
Place, publisher, year, edition, pages
2007. Vol. 68, no 5-6, 253-269 p.
alumina scale, FeCrAl alloy, impedance spectroscopy, conductivity, ionic diffusivity, beta-nial alloy, cr-al-alloys, alumina scales, electrochemical method, impedance spectroscopy, oxidation behavior, kanthal af, alpha-alumina, al2o3 scales, dry o-2
IdentifiersURN: urn:nbn:se:kth:diva-17083DOI: 10.1007/s11085-007-9074-xISI: 000250582300004ScopusID: 2-s2.0-35648997906OAI: oai:DiVA.org:kth-17083DiVA: diva2:335126
QC 201008262010-08-052010-08-052013-11-20Bibliographically approved