Mechanisms of Degradation and Failure in a Plasma-Deposited Thermal Barrier Coating

1990 ◽  
Vol 112 (4) ◽  
pp. 521-526 ◽  
Author(s):  
J. T. DeMasi-Marcin ◽  
K. D. Sheffler ◽  
S. Bose
Keyword(s):  
Thermal Barrier Coating ◽  
Damage Accumulation ◽  
Ceramic Coating ◽  
Coating Layer ◽  
Thermal Exposure ◽  
Ceramic Layer ◽  
Constitutive Behavior ◽  
Thermal Barrier ◽  
Accumulation Process ◽  
Barrier Coating

Failure of a two-layer plasma-deposited thermal barrier coating is caused by cyclic thermal exposure and occurs by spallation of the outer ceramic layer. Spallation life is quantitatively predictable, based on the severity of cyclic thermal exposure. This paper describes and attempts to explain unusual constitutive behavior observed in the insulative ceramic coating layer, and presents details of the ceramic cracking damage accumulation process, which is responsible for spallation failure. Comments also are offered to rationalize the previously documented influence of interfacial oxidation on ceramic damage accumulation and spallation life.

scholarly journals Mechanisms of Degradation and Failure in a Plasma Deposited Thermal Barrier Coating

1989 ◽  
Author(s):  
Jeanine T. Demasi-Marcin ◽  
Keith D. Sheffler ◽  
Sudhangshu Bose
Keyword(s):  
Thermal Barrier Coating ◽  
Damage Accumulation ◽  
Ceramic Coating ◽  
Coating Layer ◽  
Thermal Exposure ◽  
Ceramic Layer ◽  
Constitutive Behavior ◽  
Thermal Barrier ◽  
Accumulation Process ◽  
Barrier Coating

Failure of a two layer plasma deposited thermal barrier coating is caused by cyclic thermal exposure and occurs by spallation of the outer ceramic layer. Spallation life is quantitatively predictable, based on the severity of cyclic thermal exposure. This paper describes and attempts to explain unusual constitutive behavior observed in the insulative ceramic coating layer, and presents details of the ceramic cracking damage accumulation process which is responsible for spallation failure. Comments also are offered to rationalize the previously documented influence of interfacial oxidation on ceramic damage accumulation and spallation life.

Classification of defects in a thermal barrier coating layer using the fuzzy C-means algorithm

2015 ◽  
Vol 16 (1) ◽  
pp. 53-57 ◽  
Author(s):  
Pyeong-Ho Kim ◽  
Jeong-Suk Kim ◽  
Jin-Hyo Park ◽  
Ku-Hyeun Lee ◽  
Yo-Seung Song ◽  
...  
Keyword(s):  
Thermal Barrier Coating ◽  
Coating Layer ◽  
Thermal Barrier ◽  
Fuzzy C Means ◽  
Barrier Coating ◽  
Fuzzy C Means Algorithm

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.

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.

scholarly journals Crack Initiation Strength of Thermal Barrier Coating Layer under Thermal Shock.

2001 ◽  
Vol 50 (3) ◽  
pp. 297-302 ◽  
Author(s):  
Masayuki ARAI ◽  
Toshio SAKUMA ◽  
Uichi IWATA ◽  
Masahiro SAITOH
Keyword(s):  
Crack Initiation ◽  
Thermal Shock ◽  
Thermal Barrier Coating ◽  
Coating Layer ◽  
Thermal Barrier ◽  
Barrier Coating

Evolution of Thermal Barrier Coating Strain Tolerance During Engine Operation and its Application to Lifing Models

2012 ◽  
Author(s):  
Markus Schaudinn ◽  
Grégoire Witz ◽  
Hans-Peter Bossmann
Keyword(s):  
Mechanical Properties ◽  
Thermal Barrier Coating ◽  
Residual Life ◽  
Propagation Model ◽  
Ceramic Layer ◽  
Limiting Factor ◽  
Thermal Barrier ◽  
Engine Operation ◽  
Strain Tolerance ◽  
Barrier Coating

Models for thermal barrier coating lifetime prediction are often based on bondcoat oxidation models leading to an end of life criterion either based on bondcoat full consumption or a critical thermally grown oxide thickness. Such models can be satisfactory on turbine parts where the most common coating delamination modes are black or grey failure which are linked to the bondcoat behaviour. Such models are not reliable for combustor parts with thick thermal barrier coating systems where the most common life limiting factor is the formation of cracks appearing in the ceramic layer few tens of microns above the bondcoat interface. This behaviour is linked to the TBC layer mechanical properties and should be described by a model taking into account the evolution of the TBC mechanical properties during engine operation, the mechanical loads in the ceramic layer and a crack propagation model in the TBC. A study of the strain tolerance of TBC from combustor parts after engine operation was performed by taking samples from combustor liners at various locations having different TBC surface temperature. The strain tolerance of TBC samples was measured by four-point bending and correlated with the TBC microstructure and various engine operation parameters. It was shown that the TBC microstructure has an influence on TBC strain tolerance, and that the evolution of the TBC strain tolerance during engine operation is linked to the TBC temperature as well as the operating hours. The data have been used to develop a predictive model of the evolution of the TBC strain tolerance during engine operation. This model allows optimization of parts reconditioning interval, and provides tools for determining the residual life of coated components.

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