Probe electrode study of cathodically polarized PtIr-YSZ interfaces
- 7 Downloads
Local cathodic polarizations of yttria-stabilized zirconia were carried out with a PtIr probe as the working electrode in a controlled atmosphere high temperature scanning probe microscope to investigate the reduction of zirconia. Impedance spectroscopy was performed at 650 °C during increasing and decreasing polarization, in a range between 0.5 and − 2 V in 9% H2 in N2 saturated with water vapor at room temperature (25 °C). With increased polarization, the impedance spectra changed from a simple suppressed arc at low polarizations into two capacitive arcs separated by an inductive loop and followed by an inductive loop at low frequencies. Areas with high conductance as well as significantly decreased high-frequency resistances resulted from the polarizations and indicate the introduction of electronic conductivity in YSZ. Near the probe|YSZ contacts, areas with very low conductance and accumulation of Si-containing particles were observed, pointing to additional migration of silica impurities towards the probe.
KeywordsPtIr-YSZ Strong cathodic polarization Inductive impedance CAHT-SPM
Stimulating discussions with Mogens Bjerg Mogensen and Christodoulos Chatzichristodoulou are greatly appreciated.
We gratefully acknowledge financial support from Energinet.dk through the ForskEL program “Solid Oxide Fuel Cells for the Renewable Energy Transition” contract no 2014-1-12231 and from ECoProbe (DFF—4005-00129) funded by the Danish Independent Research Council.
- 7.Levy M, Fouletier J, Kleitz M (1988) Model for the electrical conductivity of reduced stabilized zirconia. Solid State Sci Technol 135:1584–1589Google Scholar
- 21.Hansen KV, Wu Y, Jacobsen T, Mogensen MB, Theil Kuhn L (2013) Improved controlled atmosphere high temperature scanning probe microscope. Rev Sci Instrum 84:073701-073701-7Google Scholar
- 24.Robie RA, Hemingway BS (1995) Thermodynamic properties of minerals and related substances at 298.15 K and 1 Bar (105 Pascals) pressure and at higher hemperatures. US Geol Surv Bull:2131Google Scholar
- 30.Holm R (1967) Stationary Contacts. In: Electric contacts, 4th edn. Springer-Verlag, Berlin, pp 18Google Scholar