scholarly journals Thermal Shock and Cycling Behavior of Thermal Barrier Coatings (TBCs) Used in Gas Turbines

10.5772/54412 ◽  
2013 ◽  
Author(s):  
Abdullah Cahit ◽  
Kazuhiro Ogawa ◽  
Ahmet Turk ◽  
Ismail Ozdemir
Keyword(s):  
Thermal Shock ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Cycling Behavior

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

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.

Investigation of Thermo-Mechanical Properties of Slurry Based Thermal Barrier Coatings under Repeated Thermal Shock

2009 ◽  
Vol 417-418 ◽  
pp. 197-200 ◽  
Author(s):  
Phuc Nguyen ◽  
Andrei G. Kotousov ◽  
Sook Ying Ho ◽  
Stuart Wildy
Keyword(s):  
Thermal Shock ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Nuclear Power ◽  
Thermal Stresses ◽  
Low Cost ◽  
Industrial Applications ◽  
Experimental Investigations ◽  
Thermal Barrier ◽  
Barrier Coatings

Thermal Barrier Coatings have existed for over 40 years, and with in the last 15 years their use in industrial applications has dramatically increased. Thermal Barrier Coatings (TBCs) are currently used in gas turbines, diesel engines, throughout aerospace and nuclear power industries. The purpose of TBC is to reduce temperature and thermal stresses, and, as a result, increase the reliability and life of load-bearing components subjected to high temperature or temperature flux. However, TBCs often fail under thermal cyclic loading with reliability still being the major issue impeding their wide-spread applications. The focus of this work is on experimental investigations of zirconia/nickel graded TBC system, subject to thermal shock loading. The graded TBC systems were fabricated utilising a recently developed slurry spray manufacturing technique. This is a robust technique, and is able to cover large and curved surfaces at low cost, and provides many advantages in comparison with its alternatives. This paper describes the developed technique and presents selected results of thermo-mechanical and fracture testing of the TBCs including graded coatings fabricated using this new technique.

Highly Porous Thick Thermal Barrier Coatings Produced by Air Plasma Spraying of a Plastic-Ceramic Mixed Powder

1997 ◽  
Author(s):  
G. Gualco ◽  
S. Corcoruto ◽  
A. Campora ◽  
R. Taylor ◽  
D. Schwingel ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Plasma Spraying ◽  
Thermal Barrier Coatings ◽  
Gas Turbines ◽  
Thermal Barrier ◽  
High Porosity ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Barrier Coatings ◽  
Segmentation Cracks

Abstract In order to increase the efficiency of heavy duty gas turbines for power generation and to reduce their emissions, higher combustion chamber temperature is required; a considerable improvement of the insulation properties of the thermal barrier coatings is therefore required. 1.5 mm thick thermal barrier coatings have been deposited by air plasma spraying a mixed polyester-zirconia powder; by this process high porosity, up to 22%, has been achieved together with a good deposition efficiency (about 50%); the coating microstructure has been thoroughly examined by quantitative image analysis, determining the pores size distribution and the vertical segmentation cracks density. Thermal shock tests showed a life improvement with respect to the state-of-art by a factor > 100; relationships among thermal shock life, deposition rate, segmentation cracks density and porosity were determined. Thermal expansion and thermal diffusivity were measured up to 1200 °C; failure strength, failure strain and Young's modulus were determined by a four-point bending technique.

Time-Dependent Behavior and Fracture of Functionally Graded Thermal Barrier Coatings under Thermal Shock

2005 ◽  
Vol 492-493 ◽  
pp. 379-384 ◽  
Author(s):  
Klod Kokini ◽  
Sudarshan V. Rangaraj
Keyword(s):  
Thermal Shock ◽  
Thermal Barrier Coatings ◽  
Functionally Graded ◽  
Yttria Stabilized Zirconia ◽  
Time Dependent ◽  
Thermal Barrier ◽  
Stabilized Zirconia ◽  
Barrier Coatings ◽  
Dependent Behavior ◽  
Bond Coat Alloy

The thermal fracture and its dependence on time-dependent behavior in functionally graded yttria stabilized zirconia - NiCoCrAlY bond coat alloy thermal barrier coatings was studied. The response of three coating architectures of similar thermal resistance to laser thermal shock tests was considered, experimentally and computationally.

Vacuum Plasma Sprayed ZrO2-Based Thermal Barrier Coatings for Aerospace Applications

1998 ◽  
Author(s):  
T. Brzezinski ◽  
A. Cavasin ◽  
S. Grenier ◽  
E. Kharlanova ◽  
G. Kim ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Barrier Coatings ◽  
Temperature Drop ◽  
Single Step ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Vacuum Plasma Spray ◽  
Barrier Coatings ◽  
Vacuum Plasma ◽  
Plasma Sprayed

Abstract Zirconia-based thermal barrier coatings (TBCs), produced using Vacuum Plasma Spray (VPS) technology, were recently subjected to burner rig testing. The VPS TBC performance was compared to TBCs deposited using conventional Atmospheric Plasma Sprayed (APS) and Electron Beam Physical Vapor Deposition (EB-PVD) techniques. All of the coatings consisted of an MCrAlY bond coat and a partially stabilized ZrO2-8%Y2O3 (PSZ) top coat. The TBC coated pins (6.35 mm in diameter) were tested using gas temperatures ranging from 110CC to 1500°C. The pins were tested to failure under severe conditions (1500°C gas temperature, with no internal cooling). The initial testing indicated that under typical operating gas temperatures (1400°C), the VPS TBC performance was comparable, if not superior, to conventional TBCs. Following the encouraging results, thick composite TBCs, produced in a single-step operation, were investigated. Preliminary work on ZrO2-8% Y2O3/Ca2SiO4 composite TBCs with interlayer grading included thermal shock testing and temperature drop measurements across the TBC. The composite TBC thicknesses ranged from 850µm to 1.8 mm. Initial results indicate that thick adherent composite TBCs, with high resistance to severe thermal shock, can be produced in a single step using the VPS process.

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