Real-time acoustic emission testing based on wavelet transform for the failure process of thermal barrier coatings

2008 ◽  
Vol 93 (23) ◽  
pp. 231906 ◽  
Author(s):  
L. Yang ◽  
Y. C. Zhou ◽  
W. G. Mao ◽  
C. Lu
Keyword(s):  
Acoustic Emission ◽  
Wavelet Transform ◽  
Real Time ◽  
Thermal Barrier Coatings ◽  
Failure Process ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Emission Testing ◽  
Acoustic Emission Testing

scholarly journals Influence of SiC Addition on Mechanical Behavior of Thermal Barriers with the Aid of Acoustic Emission

2021 ◽  
Vol 5 (1) ◽  
pp. 16
Author(s):  
David Jeronimo Busquets ◽  
Carlos Bloem ◽  
Amparo Borrell ◽  
Maria Dolores Salvador
Keyword(s):  
Acoustic Emission ◽  
Mechanical Behavior ◽  
Thermal Barrier Coatings ◽  
Wavelet Transforms ◽  
Coefficient Of Thermal Expansion ◽  
Microstructural Analysis ◽  
Thermal Barrier ◽  
Transfer Coefficients ◽  
Barrier Coatings ◽  
Thermal Barriers

The improvement of high temperature materials with lower heat transfer coefficients lead to the development of thermal barrier coatings (TBCs). One of the most widely used materials for thermal barrier coatings is Y2O3 stabilized ZrO2 (Y-TZP) because of its excellent shock resistance, low thermal conductivity, and relatively high coefficient of thermal expansion. The aim of this work is to study the TBCs mechanical behavior with the addition of SiC into the suspension of Y-TZP/Al2O3 by acoustic emission (AE). Additionally, a microstructural analysis and a finite elements model were carried out in order to compare results. The coatings were made by suspension plasma spray (SPS) on metal plates of 70 × 12 × 2 mm3. An intermetallic was deposited as a bond coating, followed by a coating of Y-TZP/Al2O3 with and without 15 wt.% SiC, with thicknesses between 87 and 161 μm. The AE becomes a fundamental tool in the study of the mechanical behavior of thermal barriers. The use of wavelet transforms streamlines the study and analysis of recorded sound spectra. The crack generation arises at very low stress levels.

Acoustic emission assessment of interface cracking in thermal barrier coatings

2015 ◽  
Vol 32 (2) ◽  
pp. 342-348 ◽  
Author(s):  
Li Yang ◽  
Zhi-Chun Zhong ◽  
Yi-Chun Zhou ◽  
Wang Zhu ◽  
Zhi-Biao Zhang ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Interface Cracking

Acoustic Emission Evaluation of Thermal Barrier Coatings Using the Three Point Bending Test

1991 ◽  
Author(s):  
A. T. J. Verbeek ◽  
J. M. Houben ◽  
J. A. Klostermann
Keyword(s):  
Acoustic Emission ◽  
Thermal Barrier Coatings ◽  
Light And Electron Microscopy ◽  
Wide Band ◽  
Bending Test ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Bending Tests ◽  
Three Point Bending ◽  
Resonance Sensor

Thermal Barrier coatings were tested in three point bending tests, combined with acoustic emission evaluation. The test specimens consist of a 2 mm substrate with a 0.1 mm FeCrAlY bondcoat and a 0.3 mm ZrO2/Y2O3 93/7.8 weight % topcoat. Both the topcoat and the bondcoat were air plasma sprayed under varying conditions of the substrate cooling and the length of the plasma flame. On investigating the microstructure of the coatings, using light and electron microscopy, differences could be observed, due to the various spraying techniques. The coated specimens were tested in a tensile testing machine equiped with a special tool for three point bending tests. During bending, acoustic emissions from the coating were measured, using a two channel acoustic emission apparatus. Two types of AE sensors were used, namely a 150 kHz resonance sensor and a 0.1 −1 MHz wide band sensor. The various coatings show different AE patterns, especially the bondcoats which showed differences according to the spraying techniques. The use of wide band sensors had some advantages, however they were less sensitive than resonance sensors, they take signals that were received by the resonance ones. After testing, the specimens were prepared and microscopically investigated. Herewith it was possible to establish a relationship between the measured AE signal and the type of coating and coating failure.

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