Characterization of isothermally oxidized ZrO2-8wt.%Y2O3 thermal barrier coatings by electrochemical impedance spectroscopy

    Authors

    J. W. Byeon; B. Jayaraj;Y. H. Sohn

    Comments

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    Keywords

    thermal barrier coating; electrochemical impedance spectroscopy; thermally grown oxide; isothermal oxidation; nondestructive evaluation; Engineering, Environmental; Materials Science, Multidisciplinary

    Abstract

    Electrochemical impedance spectroscopy was employed to examine ZrO2-8wt.%Y2O3 (yttria stabilized zirconia, YSZ) thermal barrier coating (TBC) as a function of isothermal exposure time at 1121 degrees C. Electrochemical impedance response (resistance and capacitance of YSZ and thermally grown oxide (TGO)) of TBC specimens was analyzed with an alternative current equivalent circuit based on the multi-layered micro-constituents of TBC, and the impedance response was correlated with microstructural changes attributed to isothermal oxidation. The resistance of YSZ was observed to increase initially and then decrease with thermal exposure. The initial increase was related to the high temperature sintering of YSZ, and the subsequent decrease was discussed in terms of microcrack initiation and electrolyte penetration. The TGO thickness was linearly correlated to the capacitance of TGO.

    Journal Title

    Eco-Materials Processing & Design Vi

    Volume

    486-487

    Publication Date

    1-1-2005

    Document Type

    Article

    Language

    English

    First Page

    145

    Last Page

    148

    WOS Identifier

    WOS:000230389400037

    ISSN

    0255-5476; 0-87849-966-0

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