scholarly journals Research Progresses on Ceramic Materials of Thermal Barrier Coatings on Gas Turbine

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 79
Author(s):  
Shuo Wu ◽  
Yuantao Zhao ◽  
Wenge Li ◽  
Weilai Liu ◽  
Yanpeng Wu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
High Performance ◽  
Ceramic Materials ◽  
Ceramic Coatings ◽  
Thermal Barrier ◽  
Structure Property ◽  
Barrier Coatings ◽  
Doping Modification

Thermal barrier coatings (TBCs) play a vitally important role in protecting the hot parts of a gas turbine from high temperature and corrosion effectively. More and more attention has been paid to the performance modification of ZrO2-based ceramics and seeking for new ceramic materials to meet requirements of gas turbine TBCs. The working principle, merits, and demerits of main technologies for coating preparation are elaborated in this paper, and the properties of new ceramic materials are reviewed. It is found that the thermal conductivity, thermal stability, mechanical properties, and other performances of traditional ZrO2-based ceramics could be improved effectively by doping modification. The emphases for new ceramic materials research were put on pyrochlores, magnetoplumbites, rare-earth tantalates, etc. Rare-earth tantalates with great potentials as new top ceramic materials were described in detail. In the end, the development directions of advanced top ceramic coatings, combining doping modification with preparation technology to regulate and control structure property of high-performance ceramic material, were put forward.

scholarly journals Ceramic Thermal Barrier Coatings for Gas Turbine Engines

1982 ◽  
Author(s):  
R. J. Bratton ◽  
S. K. Lau ◽  
C. A. Andersson ◽  
S. Y. Lee
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Critical Role ◽  
Thick Layer ◽  
Ceramic Coatings ◽  
Turbine Engines ◽  
Thermal Barrier ◽  
Gas Turbine Engines ◽  
Barrier Coatings ◽  
Combustion Gases

Ceramic thermal barrier coatings are currently under active development in the U.S. for both aircraft and industrial/Utility gas turbine operation. These coating systems generally consist of an oxidation-corrosion resistant metal bond coat of the MCrAlY type and either a single thick layer ceramic overcoat or a graded ceramic/MCrAlY overcoat. This paper summarizes studies conducted on the high-temperature corrosion resistance of ZrO2 · Y2O3, ZrO2 · MgO and Ca2SiO4 plasma sprayed coatings that are candidates for use as thermal barrier coatings in gas turbine engines. Coatings were evaluated in both atmospheric burner rig and pressurized passage tests using GT No. 2 fuel and that doped with corrosive impurities such as sodium, sulfur and vanadium. The test results showed that the coatings perform very well in the clean fuel pressurized passage tests as well as burner rig tests. With impure fuels, it was found that chemical reactions between the ceramic coatings and combustion gases/condensates played the critical role in coating degradation. This work was conducted for NASA and EPRI under contract NAS3-21377. Advanced coating development studies have also been conducted for NASA and DOE under contract DEN3-110.

Synchrotron X-Ray Diffraction to Quantify In-Situ Strain on Rare-Earth Doped Yttria-Stabilized Zirconia Thermal Barrier Coatings

2021 ◽  
Author(s):  
Quentin Fouliard ◽  
Johnathan Hernandez ◽  
Hossein Ebrahimi ◽  
Khanh Vo ◽  
Ranajay Ghosh ◽  
...  
Keyword(s):  
Rare Earth ◽  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Gas Turbine Engine ◽  
Temperature Sensing ◽  
Thermal Barrier ◽  
X Ray Diffraction ◽  
Barrier Coatings ◽  
Turbine Engine ◽  
X Ray

Abstract The recent advancement in multifunctional thermal barrier coatings (TBCs) for temperature sensing or defect monitoring has gained interest over the past decade as they have shown great potential for optimized engine operation with higher efficiency, reduced fuel consumption and maintenance costs. Specifically, sensor coatings containing luminescent ions enable materials monitoring using integrated spectral characteristics. While facilitating sensing capabilities, luminescent rare-earth dopants ideally present minimal intrusiveness for the thermal barrier coating. However, the effects of rare-earth dopant addition on thermomechanical and thermochemical properties remain unclear. Our study intends to fill this knowledge gap by characterizing coatings’ internal thermomechnical properties under realistic gas turbine engine operating temperatures. In this work, TBC configurations including industry standard coatings and sensor coatings were compared to quantify dopant intrusiveness. The TBC configurations have been characterized using high-energy synchrotron X-ray diffraction while being heated up to gas turbine engine temperatures. The TBC samples have been subjected to a single cycle thermal load with multiple ramps and holds during XRD data collection. Depth-resolved XRD was used to obtain the 2D diffraction patterns corresponding to each depth location for the determination of strain distributions along the TBCs. Internal strains and stresses acting through the coatings were quantified mostly highlighting that there is negligible variation between the standard and novel sensor coatings. Thus, the thermal response at high temperature remains unaffected with addition of luminescent dopants. This evaluation of novel coating configurations provides valuable insight for future safe implementation of these temperature sensing coatings without performance reductions.

Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

1989 ◽  
Vol 47 ◽  
pp. 426-427
Author(s):  
Ozer Unal
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Ceramic Coating ◽  
High Vacuum ◽  
Ceramic Coatings ◽  
High Energy ◽  
Thermal Barrier ◽  
Protective Oxide ◽  
Barrier Coatings ◽  
Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

Design, Preparation and Thermal Properties of (La0.4Sm0.5Yb0.1)2Zr2O7 Ceramic for Thermal Barrier Coatings

2012 ◽  
Vol 512-515 ◽  
pp. 469-473 ◽  
Author(s):  
L. Liu ◽  
Z. Ma ◽  
F.C. Wang ◽  
Q. Xu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Rare Earth ◽  
Thermal Expansion Coefficient ◽  
Thermal Barrier Coatings ◽  
Expansion Coefficient ◽  
Phonon Transport ◽  
Thermal Barrier ◽  
Barrier Coatings

According to the theory of phonon transport and thermal expansion, a new complex rare-earth zirconate ceramic (La0.4Sm0.5Yb0.1)2Zr2O7, with low thermal conductivity and high thermal expansion coefficient, has been designed by doping proper ions at A sites. The complex rare-earth zirconate (La0.4Sm0.5Yb0.1)2Zr2O7 powder for thermal barrier coatings (TBCs) was synthesized by coprecipitation-calcination method. The phase, microstructure and thermal properties of the new material were investigated. The results revealed that single phase (La0.4Sm0.5Yb0.1)2Zr2O7 with pyrochlore structure was synthesized. The thermal conductivity and the thermal expansion coefficient of the designed complex rare-earth zirconate ceramic is about 1.3W/m•K and 10.5×10-6/K, respectively. These results imply that (La0.4Sm0.5Yb0.1)2Zr2O7 can be explored as the candidate material for the ceramic layer in TBCs system.

scholarly journals Ceramic Thermal Barrier Coatings for Turbine Engine Components

1982 ◽  
Author(s):  
D. S. Duvall ◽  
D. L. Ruckle
Keyword(s):  
Thermal Barrier Coatings ◽  
Ceramic Coatings ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Turbine Engine ◽  
Thermal Environments ◽  
Strain Tolerance ◽  
Endurance Testing ◽  
Plasma Sprayed ◽  
Cooling Air

The durability of plasma sprayed ceramic thermal barrier coatings subjected to cyclic thermal environments has been improved substantially by improving the strain tolerance of the ceramic structure and also by controlling the substrate temperature during the application of the coating. Improved strain tolerance was achieved by using ceramic structures with increased porosity, microcracking or segmentation. Plasma spraying on a controlled-temperature substrate also has been shown to improve durability by reducing harmful residual stresses. The most promising of the strain tolerant ceramic coatings have survived up to 6000 cycles of engine endurance testing with no coating or vane platform damage. In side-by-side engine tests, thermal barrier coatings have shown that they greatly reduce platform distress compared to conventionally coated vanes in addition to permitting reductions in cooling air and attendant increases in engine efficiency.

scholarly journals Analysis of the energetic/environmental performances of gas turbine plant: Effect of thermal barrier coatings and mass of cooling air

2009 ◽  
Vol 13 (1) ◽  
pp. 147-164 ◽  
Author(s):  
Ion Ion ◽  
Anibal Portinha ◽  
Jorge Martins ◽  
Vasco Teixeira ◽  
Joaquim Carneiro
Keyword(s):  
Thermal Conductivity ◽  
Gas Turbine ◽  
Thermal Barrier Coatings ◽  
Turbine Blades ◽  
Heat Transfer Analysis ◽  
Thermal Barrier ◽  
Inlet Temperature ◽  
Barrier Coatings ◽  
Cooling Air Flow ◽  
Cooling Air

Zirconia stabilized with 8 wt.% Y2O3 is the most common material to be applied in thermal barrier coatings owing to its excellent properties: low thermal conductivity, high toughness and thermal expansion coefficient as ceramic material. Calculation has been made to evaluate the gains of thermal barrier coatings applied on gas turbine blades. The study considers a top ceramic coating Zirconia stabilized with 8 wt.% Y2O3 on a NiCoCrAlY bond coat and Inconel 738LC as substrate. For different thickness and different cooling air flow rates, a thermodynamic analysis has been performed and pollutants emissions (CO, NOx) have been estimated to analyze the effect of rising the gas inlet temperature. The effect of thickness and thermal conductivity of top coating and the mass flow rate of cooling air have been analyzed. The model for heat transfer analysis gives the temperature reduction through the wall blade for the considered conditions and the results presented in this contribution are restricted to a two considered limits: (1) maximum allowable temperature for top layer (1200?C) and (2) for blade material (1000?C). The model can be used to analyze other materials that support higher temperatures helping in the development of new materials for thermal barrier coatings.

Field Evaluation of 2CaO-SiO2-CaO-ZrO2 Thermal Barrier Coating on Gas Turbine Vanes

1997 ◽  
Author(s):  
N. Mifune ◽  
Y. Harada ◽  
H. Taira ◽  
S. Mishima
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Field Evaluation ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Thermal Change ◽  
Barrier Coating ◽  
Turbine Vanes ◽  
Higher Temperature

Abstract Higher-temperature operation in a gas turbine has urged development of heat-resistant coatings and thermal barrier coatings. We have developed a 2CaO-SiO2-CaO-ZrO2 based thermal barrier coating. This coating should effectively prevent separation of the coating by relieving the shear stress generated due to thermal change of environment between layers with dissimilar properties. The coating was applied to stationary vanes of an actual gas turbine in a 25,000-hour test. This paper describes the results of the field test.

Influence of Bondcoat Topography on the Properties of Suspension Sprayed YSZ Thermal Barrier Coatings

2021 ◽  
Author(s):  
Filofteia-Laura Toma ◽  
Julia Sagel ◽  
Christoph Leyens ◽  
Karel Slámečka ◽  
Serhii Tkachenko ◽  
...  
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Thermal Spraying ◽  
Ceramic Coatings ◽  
Cycling Performance ◽  
Thermal Barrier ◽  
Oxide Ceramic ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Direct Laser

Abstract Intensive R&D work of more than one decade has demonstrated many unique coating properties; particularly for oxide ceramic coatings fabricated by suspension thermal spraying technology. Suspension spraying allows producing yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBC) with columnar microstructure; similar to those produced by electron-beam physical vapor deposition (EB-PVD); and vertically cracked morphologies; with a generally low thermal conductivity. Therefore; suspension sprayed YSZ TBCs are seen as an alternative to EB-PVD coatings and those produced by conventional air plasma spray (APS) processes. Nonetheless; the microstructure of the YSZ topcoat is strongly influenced by the properties of the metallic bondcoat. In this work; direct laser interference patterning (DLIP) was applied to texture the surface topography of Ni-alloy based plasma sprayed bondcoat. Suspension plasma spraying (SPS) was applied to produce YSZ coatings on top of as-sprayed and laser-patterned bondcoat. The samples were characterized in terms of microstructure; phase composition and thermal cycling performance. The influence of the bondcoat topography on the properties of suspension sprayed YSZ coatings is presented and discussed.

scholarly journals The Numerical Modeling of Thermal Stress Distribution in Thermal Barrier Coatings

2017 ◽  
Vol 62 (3) ◽  
pp. 1433-1437
Author(s):  
A. Jasik
Keyword(s):  
Thermal Stress ◽  
Stress Distribution ◽  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Thermal Spraying ◽  
Ceramic Coatings ◽  
Thermal Barrier ◽  
Insulation Layer ◽  
Barrier Coatings ◽  
Thermal Stress Distribution

Abstract The paper presents the results of numerical calculations of temperature and thermal stress distribution in thermal barrier coatings deposited by thermal spraying process on the nickel based superalloy. An assumption was made to apply conventional zirconium oxide modified with yttrium oxide (8YSZ) and apply pyrochlore type material with formula La2Zr2O7. The bond coat was made of NiCoCrAlY. Analysis of the distribution of temperature and stresses in ceramic coatings of different thicknesses was performed in the function of bond-coat thickness and the type of ceramic insulation layer. It was revealed that the thickness of NiCrAlY bond-coat has not significant influence on the stress distribution, but there is relatively strong effect on temperature level. The most important factor influenced on stress distribution in TBC system is related with type and properties of ceramic insulation layer.

Sign in / Sign up

Export Citation Format

Share Document