Acoustic emission source analysis of plasma sprayed thermal barrier coatings during four-point bend tests

2001 ◽  
Vol 139 (1) ◽  
pp. 55-62 ◽  
Author(s):  
X.Q. Ma ◽  
S. Cho ◽  
M. Takemoto
Keyword(s):  
Acoustic Emission ◽  
Thermal Barrier Coatings ◽  
Emission Source ◽  
Source Analysis ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Acoustic Emission Source ◽  
Bend Tests ◽  
Point Bend ◽  
Plasma Sprayed

Acoustic Emission Studies of Thermal Barrier Coatings during Cyclic Four Point Bend Tests

1996 ◽  
Author(s):  
J. Voyer ◽  
F. Gitzhofer ◽  
M.L. Boulos ◽  
J. Dionne
Keyword(s):  
Acoustic Emission ◽  
Thermal Barrier Coatings ◽  
Peak Frequency ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Emission Signal ◽  
Barrier Coating ◽  
Bend Tests ◽  
Point Bend ◽  
Plasma Sprayed

Abstract In this study, Acoustic Emission (AE) signals are used to monitor the degradation of plasma sprayed Thermal Barrier Coatings (TBC) using cyclic four point bend tests. Signal analysis both in time and frequency domains is carried out in order to identify the key parameters which can be used to classify the acoustic emission signals as a function of the damage mechanisms. This classification offers a mean of prediction of the long-term behavior of the thermal barrier coating based on the acoustic emission signal signature at the early stages of bench testing. The samples consist of a Nickel-based alloy blade coated with a duplex TBC made of a 150 μm thick bond coat covered with a 300 μm thick partially-stabilized zirconia coating. Tests were performed on unnotched and perpendicularly notched samples in order to discriminate the AE from perpendicular cracks. Two broadband transducers are used for acquisition of acoustic emission signals. Measuring the time between signal detection by each of the two transducers provides a means of determination of the location of the source of the acoustic signals. A classification of the signals based on their energy and their maximum peak frequency is presented. A comparison is made between the degradation mechanisms of TBC under thermal cycling conditions that were presented elsewhere (1) and the results of four point bend tests presented here.

Acoustic Emission Evaluation of Plasma-Sprayed Thermal Barrier Coatings

1985 ◽  
Vol 107 (1) ◽  
pp. 142-146 ◽  
Author(s):  
C. C. Berndt
Keyword(s):  
Acoustic Emission ◽  
Thermal Barrier Coatings ◽  
Thermal Protection ◽  
Failure Behavior ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Ceramic Components ◽  
And Performance ◽  
Complex Phenomena ◽  
Plasma Sprayed

Acoustic emission techniques have recently been used in a number of studies to investigate the performance and failure behavior of plasma-sprayed thermal barrier coatings. Failure of the coating is a complex phenomena, especially when the composite nature of the coating is considered in the light of possible failure mechanisms. Thus it can be expected that both the metal and ceramic components (i.e., the bond coat and ceramic overlay) of a composite thermal protection system influence the macroscopic behavior and performance of the coating. The aim of the present work is to summarize the “state-of-the-art” in terms of this initial work and indicate where future progress may be made.

Sign in / Sign up

Export Citation Format

Share Document