Title

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

Authors

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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