Thermal Nondestructive Testing of Thermal-Barrier Coatings of Turbine Buckets

Вавилов, В. П.; Маринетти, С.; Cernuschi, F.; Roba, D.

doi:10.1007/s11181-005-0194-6

Cited by 9 publications

(2 citation statements)

References 16 publications

(32 reference statements)

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“…Both samples contained machined recesses with different areas and depths, as shown in Figures (10) and (11). To conduct the tests, the samples were pressed against a metallic surface such that the machined recesses acted as differentlysized delamination regions, while scanning was performed on the upper (smooth) surface of the samples.…”

Section: Resultsmentioning

confidence: 99%

IFFT-Based Microwave Non-Destructive Testing for Delamination Detection and Thickness Estimation

Jawad

Akbar

2021

IEEE Access

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Microwave Non-Destructive Testing (NDT) techniques for dielectric coatings are vital processes in many industrial applications due to their superior defect detection capabilities over traditional NDT methods. However, the limited bandwidth and post-processing complexities of these techniques cause them to fall short of accurately estimating the delamination thickness in such structures. In this paper, a novel low-complexity signal processing method is proposed to estimate the delamination thickness in metalbacked dielectric coatings using bandwidth-limited Open-Ended Rectangular Waveguide (OERW) probes. Here, Inverse Fast Fourier Transform (IFFT) process is used to convert the measured complex reflection coefficients at the surface of the coating to the time domain. Next, the amplitude of a specific time step is used to accurately estimate the delamination thickness without extra time-consuming processing. Using a 3 mm-thick macor samples with machined defects, the proposed technique is validated by correctly estimating delamination thickness down to 0.4 mm using an OERW probe with 13.5 GHz bandwidth. Hence, this technique overcomes the challenge of the OERW's limited bandwidth, which highly affects the possibility of tracking shifting in the peak reflection in the time domain. Moreover, the proposed method does not add to the complexity of the NDT process, which makes it suitable for in-situ real time applications. Hence, following this approach would be of great importance to numerous industries, where accurate thickness estimation of minute delamination in coatings is essential to avoid system failure.

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Section: Resultsmentioning

confidence: 99%

IFFT-Based Microwave Non-Destructive Testing for Delamination Detection and Thickness Estimation

Jawad

Akbar

2021

IEEE Access

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“…Vavilov et al investigated the performances of PPT, the logarithm polynomial and the PCA approaches in terms of the SNR on the same set of coated samples containing different types of defects, and they concluded that PPT technique shows the highest SNR compared to the others techniques, when the first significant frequency is considered in the Fourier analysis (Ref 39,45).…”

Section: Defect Detectability Enhancementmentioning

confidence: 99%

Thirty Years of Thermal Barrier Coatings (TBC), Photothermal and Thermographic Techniques: Best Practices and Lessons Learned

Cernuschi

Bison

2022

J Therm Spray Tech

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With the adoption of thermal barrier coatings (TBCs) to protect the hot parts of gas turbines at the end of the last century, the characterization of their thermophysical properties and the evaluation of their state of integrity has become necessary. That leads to the development and/or the adaptation of photothermal and thermographic techniques to meet the newly requirements that have emerged. Whereas this is not an all-encompassing review of all the literature on the subjects, this work summarizes the research and the development of techniques specifically aimed at measuring the thermophysical properties, the characterization of the microstructure and the identification of adhesion defects to the metal component of the TBCs. In the following, the best practices, the lessons learned, the successes and the defeats experienced along almost thirty years will be summarized.

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High-precision nondestructive evaluation of a thermal barrier coating based on perovskite quantum dot anion exchange

Han,

Ding,

Wang

et al. 2024

Nano Res.

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Thermal Nondestructive Testing of Thermal-Barrier Coatings of Turbine Buckets

Abstract: The thermal inspection of thermal-barrier coatings of turbine buckets is briefly reviewed. An inspecting and data-processing technique is proposed and illustrated by experimental results.

Cited by 9 publications

References 16 publications

IFFT-Based Microwave Non-Destructive Testing for Delamination Detection and Thickness Estimation

IFFT-Based Microwave Non-Destructive Testing for Delamination Detection and Thickness Estimation

Thirty Years of Thermal Barrier Coatings (TBC), Photothermal and Thermographic Techniques: Best Practices and Lessons Learned

High-precision nondestructive evaluation of a thermal barrier coating based on perovskite quantum dot anion exchange

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