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Quality Assurance Evaluation of Thermal Barrier Coatings by Electrochemical Impedance Spectroscopy

Published online by Cambridge University Press:  17 March 2011

Jianqi Zhang ,
Danyash Tamboli  and
Vimal Desai
Jianqi Zhang
Affiliation:
Advanced Materials Processing & Analysis Center, University of Central Florida, Orlando, FL 32816-2450, U. S. A.
Danyash Tamboli
Affiliation:
Advanced Materials Processing & Analysis Center, University of Central Florida, Orlando, FL 32816-2450, U. S. A.
Vimal Desai
Affiliation:
Advanced Materials Processing & Analysis Center, University of Central Florida, Orlando, FL 32816-2450, U. S. A.
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Abstract

The technique of electrochemical impedance spectroscopy (EIS) was used to examine the behavior of intact thermal barrier coatings (TBC) at ambient temperature. Cross-sectional morphological examination of TBC was conducted by scanning electron microscope (SEM). By correlating the SEM visual examination with EIS data, TBC was characterized non-destructively. A model of EIS alternative current (AC) equivalent circuit was proposed to establish the relationship between the EIS elemental parameters in the circuit and the microstructural characteristics of TBC. A linear relationship was found to exist between the electrical impedance of TBC topcoat and the thickness of the topcoat. The porosity of TBC top coat showed a linear relationship with the capacitance of ceramic TBC, and the pore shape in the TBC topcoat was represented by the value of the electrical impedance of the pore. The result in the study has demonstrated that EIS can be used as a non-destructive evaluation (NDE) technique for quality assurance of TBC.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 645: Symposium M – Thermal Barrier Coatings-2000 , 2000 , M8.6.1
Copyright
Copyright © Materials Research Society 2001

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References

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