Ageing evaluation of thermal barrier coating: comparison between pulsed thermography and thermal wave interferometry

The component of the hot gas path in gas turbines can survive to very high temperatures because they are protected by ceramic Thermal Barrier Coating (TBC); the failure of such coating can dramatically reduce the component life. A reliable assessment of the Coating integrity and/or an Incipient TBC Damage Detection can help both in optimizing the inspection intervals and in finding the appropriate remedial actions. This study gives the TBC integrity; so other methods are required, like thermography to obtain indications of TBC delamination. Pulsed Thermography detects coating detachments and interface defects, with a large area of view but a spatial resolution of few mm. The mentioned techniques as a whole constitute a powerful tool for the life assessment of thermal barrier coating.

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Investigation of Delamination in Thermal Barrier Coating by Pulsed Thermography

10.21611/qirt.2018.p29 ◽

2018 ◽

Author(s):

W. Kim ◽

R. Shrestha ◽

S. Myoung

Keyword(s):

Thermal Barrier Coating ◽

Thermal Barrier ◽

Pulsed Thermography ◽

Barrier Coating

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Thickness measurement of thermal barrier coating by pulsed thermography

10.1117/12.2602765 ◽

2021 ◽

Author(s):

Sen Wang ◽

Ning Tao ◽

Jing He ◽

Chao Ge ◽

Shixing Wang ◽

...

Keyword(s):

Thermal Barrier Coating ◽

Thickness Measurement ◽

Thermal Barrier ◽

Pulsed Thermography ◽

Barrier Coating

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Research on detection of thickness of thermal barrier coating by laser transmission infrared thermal wave method

Infrared and Laser Engineering ◽

10.3788/irla201746.0704003 ◽

2017 ◽

Vol 46 (7) ◽

pp. 704003

Author(s):

李永君 Li Yongjun ◽

肖俊峰 Xiao Junfeng ◽

朱立春 Zhu Lichun ◽

张炯 Zhang Jiong ◽

高斯峰 Gao Sifeng ◽

...

Keyword(s):

Thermal Barrier Coating ◽

Thermal Wave ◽

Thermal Barrier ◽

Wave Method ◽

Barrier Coating ◽

Thermal Wave Method

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Thermal Modeling and Analysis of a Thermal Barrier Coating Structure Using Non-Fourier Heat Conduction

Journal of Heat Transfer ◽

10.1115/1.4006976 ◽

2012 ◽

Vol 134 (11) ◽

Cited By ~ 4

Author(s):

Stephen Akwaboa ◽

Patrick Mensah ◽

Ebubekir Beyazouglu ◽

Ravinder Diwan

Keyword(s):

Heat Flux ◽

Heat Conduction ◽

Temperature Distribution ◽

Thermal Barrier Coating ◽

Thermal Wave ◽

Heat Conduction Equation ◽

Thermal Barrier ◽

Hyperbolic Heat Conduction ◽

Barrier Coating ◽

Fourier Heat Conduction

This paper presents a numerical solution of the hyperbolic heat conduction equation in a thermal barrier coating (TBC) structure under an imposed heat flux on the exterior of the TBC. The non-Fourier heat conduction equation is used to model the heat conduction in the TBC system that predicts the heat flux and the temperature distribution. This study presents a more realistic approach to evaluate in-service performance of thin layers of TBCs typically found in hot sections of land based and aircraft gas turbine engines. In such ultrafast heat conduction systems, the orders of magnitude of the time and space dimensions are extremely short which renders the traditional Fourier conduction law, with its implicit assumption of infinite speed of thermal propagation, inaccurate. There is, therefore, the need for an advanced modeling approach for the thermal transport phenomenon taking place in microscale systems. A hyperbolic heat conduction model can be used to predict accurately the transient temperature distribution of thermal barrier structures of turbine blades. The hyperbolic heat conduction equations are solved numerically using a new numerical scheme codenamed the mean value finite volume method (MVFVM). The numerical method yields minimal numerical dissipation and dispersion errors and captures the discontinuities such as the thermal wave front in the solution with reliable accuracy. Compared with some traditional numerical methods, the MVFVM method provides the ability to model the behavior of the single phase lag thermal wave following its reflection from domain boundary surfaces. In addition, parametric studies of properties of the substrate on the temperature and the heat flux distributions in the TBC revealed that relaxation time of the substrate material, unlike the thermal diffusivity and thermal conductivity has very little effect on the transient thermal response in the TBC. The study further showed that for thin film structures subject to short time durations of heat flux, the hyperbolic model yields more realistic results than the parabolic model.

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HOT CORROSION OF CERIA-YTTRIA STABILIZED ZIRCONIA PLASMA SPRAYED THERMAL BARRIER COATING BY EUTECTIC VANDIUM PENTAOXIDE-SODIUM SULFATE

THE IRAQI JOURNAL FOR MECHANICAL AND MATERIALS ENGINEERING ◽

10.32852/iqjfmme.vol18.iss1.83 ◽

2018 ◽

Vol 18 (1) ◽

pp. 182-192 ◽

Cited By ~ 1

Author(s):

Mohammed J Kadhim ◽

Mohammed H Hafiz ◽

Maryam A Ali Bash

Keyword(s):

Thermal Barrier Coating ◽

Hot Corrosion ◽

Monoclinic Phase ◽

Volume Fraction ◽

High Volume ◽

Thermal Barrier ◽

Air Plasma ◽

Plan View ◽

Barrier Coating ◽

Plasma Sprayed

The high temperature corrosion behavior of thermal barrier coating (TBC) systemconsisting of IN-738 LC superalloy substrate, air plasma sprayed Ni24.5Cr6Al0.4Y (wt%)bond coat and air plasma sprayed ZrO2-20 wt% ceria-3.6 wt% yttria (CYSZ) ceramic coatwere characterized. The upper surfaces of CYSZ covered with 30 mg/cm2 , mixed 45 wt%Na2SO4-55 wt% V2O5 salt were exposed at different temperatures from 800 to 1000 oC andinteraction times from 1 up to 8 h. The upper surface plan view of the coatings wereidentified for topography, roughness, chemical composition, phases and reaction productsusing scanning electron microscopy, energy dispersive spectroscopy, talysurf, and X-raydiffraction. XRD analyses of the plasma sprayed coatings after hot corrosion confirmed thephase transformation of nontransformable tetragonal (t') into monoclinic phase, presence ofYVO4 and CeVO4 products. Analysis of the hot corrosion CYSZ coating confirmed theformation of high volume fraction of YVO4, with low volume fractions of CeOV4 and CeO2.The formation of these compounds were combined with formation of monoclinic phase (m)from transformation of nontransformable tetragonal phase (t').

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