Intrinsic and Extrinsic Variable Effects on Thermal Barrier Coatings Life

2002 ◽  
Author(s):  
Zaher Mutasim
Keyword(s):  
Thermal Barrier Coatings ◽  
Laboratory Testing ◽  
Ceramic Coating ◽  
The Other ◽  
Interface Temperature ◽  
Thermal Barrier ◽  
Mechanical And Thermal Properties ◽  
Barrier Coatings ◽  
Gaseous Environment ◽  
Barrier Coating

Thermal barrier coating life is dependent on many intrinsic and extrinsic variables within the environment that they operate within. Intrinsic variables include material composition, mechanical and thermal properties, microstructure and ceramic coating thickness. On the other hand, extrinsic variables include cycle time, interface and top surface temperatures, and the gaseous environment, among others. Laboratory testing was conducted to determine the effects of these variables on TBC life. This paper addresses TBC life as a function of microstructure, thickness, and interface temperature.

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.

Evaluation of CeSZ Thermal Barrier Coatings for Diesels

2000 ◽  
Author(s):  
P.J. Huang ◽  
J.J. Swab ◽  
P.J. Patel ◽  
W.S. Chu
Keyword(s):  
Thermal Conductivity ◽  
Thermal Expansion ◽  
Thermal Barrier Coatings ◽  
Coefficient Of Thermal Expansion ◽  
Fuel Efficiency ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Mechanical And Thermal Properties ◽  
Barrier Coatings ◽  
Spray Process

Abstract The development of thermal barrier coatings (TBCs) for diesel engines has been driven by the potential improvements in engine power and fuel efficiency that TBCs represent. TBCs have been employed for many years to reduce corrosion of valves and pistons because of their high temperature durability and thermal insulative properties. There are research programs to improve TBCs wear resistance to allow for its use in tribologically intensive areas of the engine. This paper will present results from tribological tests of ceria stabilized zirconia (CeSZ). The CeSZ was applied by atmospheric plasma spray process. Various mechanical and thermal properties were measured including wear, coefficient of thermal expansion, thermal conductivity, and microhardness. The results show the potential use of CeSZ in wear sensitive applications in diesel applications. Keywords: Thermal Barrier Coating, Diesel Engine, Wear, Thermal Conductivity, and Thermal Expansion

Mechanical Properties of Thermal Barrier Coatings at Room Temperature

2005 ◽  
Vol 290 ◽  
pp. 336-339 ◽  
Author(s):  
G. Guidoni ◽  
Y. Torres Hernández ◽  
Marc Anglada
Keyword(s):  
Mechanical Properties ◽  
Thermal Barrier Coatings ◽  
Room Temperature ◽  
Inconel 625 ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Bending Tests ◽  
Four Point Bending ◽  
Barrier Coating ◽  
Plasma Sprayed

Four point bending tests have been carried out on a thermal barrier coating (TBC) system, at room temperature. The TBC system consisted of a plasma sprayed Y-TZP top coat with 8 % in weight of Yttria, a bond coat of NiCrAlY and a Ni-based superalloy Inconel 625 as substrate. The TBC coating was deposited on both sides of the prismatic specimens. Efforts have been done in detecting the damage of the coating by means of Maltzbender et al [1] model.

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.

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.

A review of thermal barrier coatings for improvement in thermal efficiency of both gasoline and diesel reciprocating engines

2020 ◽  
pp. 146808742097801
Author(s):  
Noboru Uchida
Keyword(s):  
Thermal Barrier Coatings ◽  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Exhaust Emissions ◽  
Thermal Barrier ◽  
Cylinder Wall ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Reciprocating Engines ◽  
History Of

Cylinder wall heat insulation using thermal barrier coatings is both an old and new thermal efficiency improvement technology for internal combustion engines. This review first outlines the history of thermal barrier coating (TBC) technologies applied to reciprocating engines from the 1970s up to the present day, by referring to several distinctive reference papers. These research efforts, however, present a number of conflicting conclusions. In order to understand why the results did not always coincide, certain key features of TBC’s studied in the reference papers were then investigated in more detail, such as thermal properties, porosity, surface roughness, and translucence/emissivity. The studies of not only the effect of TBC’s on diesel exhaust emissions, but TBC effects on gasoline and HCCI performance and exhaust emissions, are also reviewed for the investigation of manifold TBC characteristics. Finally, state of the art techniques and constraints were reviewed for experimental and numerical analysis of the heat transfer mechanism, which should be applied to TBC research.

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.

Relation between Concave Cone 3 Dimension Topography and Residual Stress in Thermal Barrier Coatings

2011 ◽  
Vol 291-294 ◽  
pp. 172-175
Author(s):  
Zhi Yong Han ◽  
Huan Wang
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Compressive Stress ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Barrier Coating ◽  
Stress Changes ◽  
Unit Stress

Considering the concave cone 3 dimension interface topography unit, the distribution of residual stress in thermal barrier coating was calculated using ABAQUS soft by finite element method. The calculating result shows that the residual stress is affected by interface topography unit obviously. Compressive stress exists in concave cone topography unit. Stress concentrates in boundary of topography unit and reaches maximal value at the lowest place of the topography. Compressive stress changes with the size of topography unit and the space between two topography units distinctly.

Determination of Thermal Barrier Coatings Average Surface Temperature After Engine Operation for Lifetime Validation

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Grégoire Witz ◽  
Hans-Peter Bossmann
Keyword(s):  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Operating Conditions ◽  
Thermal Barrier ◽  
Engine Operation ◽  
Barrier Coatings ◽  
Average Surface ◽  
Barrier Coating

Assessment of ex-service parts is important for the power generation industry. It gives us the opportunity to correlate part conditions to specific operating conditions like fuel used, local atmospheric conditions, operating regime, and temperature load. For assessment of thermal barrier coatings, one of the most valuable pieces of information is the local thermal condition. A method has been developed in Alstom, allowing determination of a thermal barrier coating average surface temperature after engine operation. It is based on the analysis of the phase composition of the thermal barrier coating by the acquisition of an X-ray diffraction spectrum of the coating surface, and its analysis using Rietveld refinement. The method has been validated by comparing its outcome to thermal models and base metal temperature mapping data. It is used for assessment of combustor and turbine coatings with various purposes: Determination of remnant coating life, building of lifing models, or determination of the coating degradation mechanisms under some specific operating conditions. Examples will be presented showing applications of this method.

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