NDE of degradation of thermal barrier coating by means of impedance spectroscopy

Ogawa, Kōichi; Minkov, Dorian; Shoji, Tetsuo; Sato, Minoru; Hashimoto, Hideo

doi:10.1016/s0963-8695(98)00069-3

Cited by 70 publications

(21 citation statements)

References 8 publications

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“…There is no obvious influence of voltage amplitude on impedance spectra as long as it can ensure that the current is greater than the range of instrument. However, the electrode size brings large error in the measurement error, which also is founded in Ogawa' IS experimental investigation on layer thicknesses of TBCs [18], causing 330% the maximum measurement error. Therefore, it is necessary to quantify the measurement error for precise quantitative evaluation.…”

Section: Introductionmentioning

confidence: 96%

Error and modification in thermal barrier coatings measurement using impedance spectroscopy

Yang

Zhu

et al. 2017

Ceramics International

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A B S T R A C TIn impedance spectroscopy testing of metal/ceramic multi-layers, such as thermal barrier coatings (TBCs), in order to avoid electric leakage, asymmetric electrode is widely adopted. However, how is electric field distribution in asymmetric electrode system, what error does it bring to measurement results, and how to modify these errors etc., are still not understood. In this study, electric field divergence in TBCs measurement induced by asymmetric electrode is investigated through solving a three-dimensional electric field equations numerically. The results show that the asymmetric electrode inevitably triggers divergence of electric field line, and as frequency decreases the divergence increases considerably. When Pt electrode diameter is chosen as 1 mm in ceramic coating, the errors in thickness measurement for both YSZ and TGO are 26.20% and 89.3%, respectively. The errors rise as both YSZ and TGO thicknesses increase, while the errors decrease as Pt electrode size increases. The error in thickness measurement for TGO layer is much larger than that for YSZ. Through present research, a scheme to eliminate the effect of electric field divergence on measurement error is proposed.

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Section: Introductionmentioning

confidence: 96%

Error and modification in thermal barrier coatings measurement using impedance spectroscopy

Yang

Zhu

et al. 2017

Ceramics International

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“…Paranjape et al [15] demonstrated that bulk impedance could be used to characterize the void fraction of two-phase flow within a 0.78 mm square microchannel. With respect to thermal interfaces, capacitance has been used with a spectroscopy technique utilizing a single electrode to detect flaws in an insulating layer [16,17]. In this paper, the perpendicular-array wire mesh sensor concept is adapted for characterization of a dielectric TIM layer.…”

Section: Introductionmentioning

confidence: 99%

Void Detection in Dielectric Films Using a Floating Network of Substrate-Embedded Electrodes

Taylor

Garimella

2014

Journal of Electronic Packaging

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A sensor is developed for simple, in situ characterization of dielectric thermal interface materials (TIMs) at bond line thicknesses less than 100 lm. The working principle is based on the detection of regions of contrasting electric permittivity. An array of long, parallel electrodes is flush-mounted into each opposing substrate face of a narrow gap interface, and exposed to the gap formed between the two surfaces. Electrodes are oriented such that their lengthwise dimension in one substrate runs perpendicular to those in the other. A capacitance measurement taken between opposing electrodes is used to characterize the interface region in the vicinity of their crossing point (junction). The electric field associated with each electrode junction is numerically simulated and analyzed. Criteria are developed for the design of electrode junction geometries that localize the electric fields. The capacitances between floating-ground electrodes in the electrode sensor configuration employed give rise to a nontrivial network of interacting capacitances which strongly influence the measured response at any junction. A generalized solution for analyzing the floating network response is presented. The technique is used to experimentally detect thermal grease spots of 0.2 mm to 1.8 mm diameter within a 25 lm interface gap. It is necessary to use the generalized solution to the capacitance network developed in this work to properly delineate regions of contrasting permittivity in the interface gap region using capacitance measurements.

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“…It could be applied not only to studying the corrosion resistance of components after surface treatment [23][24][25] but also to evaluating the integrity of components [26]. Harrison et al [27] investigated the corrosion resistance of white layer in NaOH solution using electrochemical methods.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical characteristics of white layer generated by hard milling AISI H13 steel

Yan

Zhang

et al. 2014

Int J Adv Manuf Technol

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In the field of hard cutting, researches on white layer have become more extensive and in-depth in recent years, because white layer has an important influence on the performances and life of components. Nevertheless, properties of white layer, especially its corrosion properties, have not been well understood or clearly defined. In this study, specimens with different subsurface microstructures (no obvious change, dark layer, and white layer) were produced in the process of tool wear to analyze their electrochemical properties using electrochemical methods. It was found that electrochemical properties were distinct between specimens with and without white layer. A specimen with white layer had obviously lower electrochemical impedance and more anodic steady-state open-circuit potential than that without white layer in 3.5 wt.% NaCl solution. That is to say, specimens with white layer were prone to corrosion in this solution. The results also manifest that electrochemical method can be a reliable, convenient, and nearly nondestructive method to detect white layer.

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NDE of degradation of thermal barrier coating by means of impedance spectroscopy

Cited by 70 publications

References 8 publications

Error and modification in thermal barrier coatings measurement using impedance spectroscopy

Error and modification in thermal barrier coatings measurement using impedance spectroscopy

Void Detection in Dielectric Films Using a Floating Network of Substrate-Embedded Electrodes

Electrochemical characteristics of white layer generated by hard milling AISI H13 steel

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