Delamination Cracking in Thermal Barrier Coating System

2002 ◽  
Vol 124 (4) ◽  
pp. 922-930 ◽  
Author(s):  
Y. C. Zhou ◽  
T. Hashida
Keyword(s):  
Thermal Stress ◽  
Temperature Gradient ◽  
Thermal Barrier Coating ◽  
Ceramic Coating ◽  
Compressive Load ◽  
Bending Moment ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Thermal Growth ◽  
Coating Delamination

Delamination cracking in thermal barrier coating (TBC) system is studied with the newly developed theoretical model. A semi-infinite long interface crack is pre-existing. The thermal stress and temperature gradient in TBC system are designated by a membrane stress P and a bending moment M. In this case, the effects of plastic deformation, creep of ceramic coating, as well as thermal growth oxidation and temperature gradient in TBC system are considered in the model due to the fact that these effects are considered in the calculation of thermal stress. The energy release rate, mode I and mode II stress intensity factors, as well as mode mixed measure ψ, are derived. The emphatic discussion about PSZ/Ni-alloy reveals that the TBC system may not fail in the form of coating delamination during the period of heat hold. However, the failure may be in the form of coating delamination during cooling or in the heating period during the second cycle or later cycles. The conclusion is consistent with the experimental observations. The delamination of ceramic coating is induced by the compressive load in the coating.

Influence of a Thermal Barrier Coating on the Performance of a Turboprop Engine

1992 ◽  
Author(s):  
J. D. MacLeod ◽  
J. C. G. Laflamme
Keyword(s):  
Surface Roughness ◽  
Thermal Barrier Coating ◽  
Coating Thickness ◽  
Ceramic Coating ◽  
National Research Council ◽  
Engine Performance ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Project Objectives ◽  
The Impact

Under the sponsorship of the Canadian Department of National Defence, the Engine Laboratory of the National Research Council of Canada has evaluated the influence of applying a thermal barrier coating on the performance of a gas turbine engine. The effort is aimed at quantifying the performance effects of a particular ceramic coating on the first stage turbine vanes. The long term objective of the program is to both assess the relative change in engine performance and compare against the claimed benefits of higher possible turbine inlet temperatures, longer time in service and increased time between overhauls. The engine used for this evaluation was the Allison T56 turboprop with the first stage turbine nozzles coated with the Chromalloy RT-33 ceramic coating. The issues addressed in testing this particular type of hot section coating were; 1) effect of coating thickness on nozzle effective flow area; 2) surface roughness influence on turbine efficiency; This paper describes the project objectives, the experimental installation, and the results of the performance evaluations. Discussed are performance variations due to coating thickness and surface roughness on engine performance characteristics. As the performance changes were small, a rigorous measurement uncertainty analysis is included. The coating application process, and the affected overhaul procedures are examined. The results of the pre- and post-coating turbine testing are presented, with a discussion of the impact on engine performance.

Effect of Spinel Growth on the Delamination of Thermal Barrier Coatings

2011 ◽  
Vol 462-463 ◽  
pp. 389-394 ◽  
Author(s):  
Wei Xu Zhang ◽  
Yong Le Sun ◽  
Tie Jun Wang
Keyword(s):  
Growth Rate ◽  
Service Life ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Unit Area ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Thermal Growth ◽  
Plasma Sprayed

The spinel growth induces undulation of the thermal growth oxide layer and decreases the service life of plasma-sprayed thermal barrier coatings. An analytical model is introduced to investigate the effect of spinel growth on the delamination of thermal barrier coating. The analytical results show that the number per unit area and the growth rate of spinel have significant influence on the delamination of thermal barrier coating. The stiffer and thicker thermal barrier coating is more easily to delaminate from the bond coat due to the existence of spinels. The effect of spinel on the delamination cannot be neglected. How to reduce the growth rate and the number of spinel is a key problem to prolong the service life of thermal barrier coatings.

STUDY FOR BLADE CERAMIC COATING DELAMINATION DETECTION FOR GAS TURBINE

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5699-5704 ◽  
Author(s):  
CHOUL-JUN CHOI ◽  
SEUNG HYUN CHOI ◽  
JAE-YEOL KIM
Keyword(s):  
Thermal Barrier Coating ◽  
Gas Turbines ◽  
Life Assessment ◽  
Thermal Barrier ◽  
Large Area ◽  
Pulsed Thermography ◽  
Barrier Coating ◽  
Reliable Assessment ◽  
Coating Delamination ◽  
Remedial Actions

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.

Cracking behaviors of EB-PVD thermal barrier coating under temperature gradient

2019 ◽  
Vol 45 (15) ◽  
pp. 18518-18528 ◽  
Author(s):  
Duoqi Shi ◽  
Jianan Song ◽  
Shaolin Li ◽  
Hongyu Qi ◽  
Xiaoguang Yang
Keyword(s):  
Temperature Gradient ◽  
Thermal Barrier Coating ◽  
Thermal Barrier ◽  
Barrier Coating
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