Effect of Thermal Barrier Coating in Sustainable Power production of Gas Turbines

The increased demand for high performance gas turbine engines has resulted in a continuous search for new base materials and coatings. With the significant developments in nickel-based superalloys, the quest for developments related to thermal barrier coating (TBC) systems is increasing rapidly and is considered a key area of research. Of key importance are the processing routes that can provide the required coating properties when applied on engine components with complex shapes, such as turbine vanes, blades, etc. Despite significant research and development in the coating systems, the scope of electrodeposition as a potential alternative to the conventional methods of producing bond coats has only been realised to a limited extent. Additionally, their effectiveness in prolonging the alloys’ lifetime is not well understood. This review summarises the work on electrodeposition as a coating development method for application in high temperature alloys for gas turbine engines and discusses the progress in the coatings that combine electrodeposition and other processes to achieve desired bond coats. The overall aim of this review is to emphasise the role of electrodeposition as a potential cost-effective alternative to produce bond coats. Besides, the developments in the electrodeposition of aluminium from ionic liquids for potential applications in gas turbines and the nuclear sector, as well as cost considerations and future challenges, are reviewed with the crucial raw materials’ current and future savings scenarios in mind.

Download Full-text

Effects of Powder Morphology, Microstructure, and Residual Stresses on Thermal Barrier Coating Thermal Shock Performance

Thermal Spray 1996: Proceedings from the National Thermal Spray Conference ◽

10.31399/asm.cp.itsc1996p0855 ◽

1996 ◽

Author(s):

J. Wigren ◽

J.-F. de Vries ◽

D. Greving

Keyword(s):

Residual Stresses ◽

Thermal Shock ◽

Thermal Barrier Coating ◽

Thermal Barrier Coatings ◽

Gas Turbines ◽

Thermal Barrier ◽

Spray Parameters ◽

Powder Morphology ◽

Barrier Coatings ◽

Barrier Coating

Abstract Thermal barrier coatings are used in the aerospace industry for thermal insulation in hot sections of gas turbines. Improved coating reliability is a common goal among jet engine designers. In-service failures, such as coating cracking and spallation, result in decreased engine performance and costly maintenance time. A research program was conducted to evaluate residual stresses, microstructure, and thermal shock life of thermal barrier coatings produced from different powder types and spray parameters. Sixteen coatings were ranked according to their performance relative to the other coatings in each evaluation category. Comparisons of residual stresses, powder morphology, and microstructure to thermal shock life indicate a strong correlation to thermal barrier coating performance. Results from these evaluations will aid in the selection of an optimum thermal barrier coating system for turbine engine applications.

Download Full-text

Evaluation of Applicability of Compact Excitation Light Source to Detection of Thermally Grown Oxide Layer in Thermal Barrier Coating for Gas Turbines

Electrical Engineering in Japan ◽

10.1002/eej.22662 ◽

2014 ◽

Vol 190 (1) ◽

pp. 1-8 ◽

Cited By ~ 5

Author(s):

Tetsuo Fukuchi ◽

Shuzo Eto ◽

Mitsutoshi Okada ◽

Tomoharu Fujii

Keyword(s):

Oxide Layer ◽

Light Source ◽

Thermal Barrier Coating ◽

Gas Turbines ◽

Thermally Grown Oxide ◽

Thermal Barrier ◽

Excitation Light ◽

Barrier Coating ◽

Thermally Grown

Download Full-text

Effects of Surface Deposition, Hole Blockage, and Thermal Barrier Coating Spallation on Vane Endwall Film Cooling

Journal of Turbomachinery ◽

10.1115/1.2720485 ◽

2006 ◽

Vol 129 (3) ◽

pp. 599-607 ◽

Cited By ~ 27

Author(s):

N. Sundaram ◽

K. A. Thole

Keyword(s):

Thermal Barrier Coating ◽

Film Cooling ◽

Gas Turbines ◽

Large Scale ◽

Leading Edge ◽

Thermal Barrier ◽

Cooling Effectiveness ◽

Barrier Coating ◽

Cooling Hole ◽

Alternate Fuels

With the increase in usage of gas turbines for power generation and given that natural gas resources continue to be depleted, it has become increasingly important to search for alternate fuels. One source of alternate fuels is coal derived synthetic fuels. Coal derived fuels, however, contain traces of ash and other contaminants that can deposit on vane and turbine surfaces affecting their heat transfer through reduced film cooling. The endwall of a first stage vane is one such region that can be susceptible to depositions from these contaminants. This study uses a large-scale turbine vane cascade in which the following effects on film cooling adiabatic effectiveness were investigated in the endwall region: the effect of near-hole deposition, the effect of partial film cooling hole blockage, and the effect of spallation of a thermal barrier coating. The results indicated that deposits near the hole exit can sometimes improve the cooling effectiveness at the leading edge, but with increased deposition heights the cooling deteriorates. Partial hole blockage studies revealed that the cooling effectiveness deteriorates with increases in the number of blocked holes. Spallation studies showed that for a spalled endwall surface downstream of the leading edge cooling row, cooling effectiveness worsened with an increase in blowing ratio.

Download Full-text

R&D Status and Needs for Improved EB-PVD Thermal Barrier Coating Performance

MRS Proceedings ◽

10.1557/proc-645-m10.1.1 ◽

2000 ◽

Vol 645 ◽

Cited By ~ 1

Author(s):

C. Leyens ◽

U. Schulz ◽

M. Bartsch ◽

M. Peters

Keyword(s):

Thermal Barrier Coating ◽

Bond Coat ◽

Gas Turbines ◽

Systems Approach ◽

Thermally Grown Oxide ◽

Thermal Barrier ◽

Factors Affecting ◽

Performance Improvements ◽

Barrier Coating ◽

Temperature Capability

ABSTRACTThe key issues for thermal barrier coating development are high temperature capability and durability under thermal cyclic conditions as experienced in the hot section of gas turbines. Due to the complexity of the system and the interaction of the constituents, performance improvements require a systems approach. However, there are issues closely related to the ceramic top coating and the bond coat, respectively. Reduced thermal conductivity, sintering, and stresses within the ceramic coating are addressed in the paper as well as factors affecting failure of the TBC by spallation. The latter is primarily governed by the formation and growth of the thermally grown oxide scale and therefore related to the bond coat. A strategy for lifetime assessment of TBCs is discussed.

Download Full-text

STUDY FOR BLADE CERAMIC COATING DELAMINATION DETECTION FOR GAS TURBINE

International Journal of Modern Physics B ◽

10.1142/s0217979208051030 ◽

2008 ◽

Vol 22 (31n32) ◽

pp. 5699-5704 ◽

Cited By ~ 3

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.

Download Full-text