Numerical Simulation for Surface Modification of Thermal Barrier Coatings by High-Current Pulse Electron Beam

2010 ◽  
Vol 654-656 ◽  
pp. 1807-1810
Author(s):  
Ying Qin ◽  
Wei Qu ◽  
Xian Xiu Mei ◽  
Sheng Zhi Hao ◽  
Ji Jun Zhao ◽  
...  
Keyword(s):  
Electron Beam ◽  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Turbine Blades ◽  
Ceramic Coatings ◽  
Pulse Electron Beam ◽  
Thermal Barrier ◽  
High Current ◽  
Barrier Coatings ◽  
Pulsed Electron Beam

High current pulsed electron beam is an effective technique for surface sealing of ceramic thermal barrier coatings prepared by electron beam physical vapor deposition. Due to the rapid remelting and solidification, the outer layers of ceramic coatings become smooth and dense, and the protective performance for turbine blades is effectively improved. Because of the complex multi-layered structures in the coatings, a high-current pulsed electron beam treatment requires specific parameter inputs which are related to the temperature field induced by electron energy deposition in the coatings. In this paper, a two-dimensional temperature simulation was performed to demonstrate the melting depth and temperature evolution in ceramic coatings treated by high-current pulsed electron beam. Different energy densities and pulses were studied and discussed for obtaining optimized parameters.

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.

Strain Tolerance and Microstructure of Thermal Barrier Coatings Produced by Electron Beam Physical Vapor Deposition Process

2006 ◽  
Vol 522-523 ◽  
pp. 267-276 ◽  
Author(s):  
Kunihiko Wada ◽  
Yutaka Ishiwata ◽  
Norio Yamaguchi ◽  
Hideaki Matsubara
Keyword(s):  
Electron Beam ◽  
High Temperature ◽  
Thermal Barrier Coatings ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Aging Treatment ◽  
Nanoindentation Test ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Strain Tolerance

Several kinds of thermal barrier coatings (TBCs) deposited by electron beam physical vapor deposition (EB-PVD) were produced as a function of electron beam power in order to evaluate their strain tolerance. The deposition temperatures were changed from 1210 K to 1303 K depending on EB power. In order to evaluate strain tolerances of the EB-PVD/TBCs, a uniaxial compressive spallation test was newly proposed in this study. In addition, the microstructures of the layers were observed with SEM and Young’s moduli were measured by a nanoindentation test. The strain tolerance in as-deposited samples decreased with an increase in deposition temperature. In the sample deposited at 1210 and 1268 K, high-temperature aging treatment at 1273 K for 10 h remarkably promoted the reduction of the strain tolerance. The growth of thermally grown oxide (TGO) layer generated at the interface between topcoat and bondcoat layers was the principal reason for this strain tolerance reduction. We observed TGO-layer growth even in the as-deposited sample. Although the thickness of the initial TGO layer in the sample deposited at high temperature was thicker, the growth rate during aging treatment was smaller than those of the other specimens. This result suggests that we can improve the oxidation resistance of TBC systems by controlling the processing parameters in the EB-PVD process.

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.

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