Isothermal oxidation behaviour of thermal barrier coatings with CoCrAlY bond coat irradiated by high-current pulsed electron beam

2014 ◽  
Vol 317 ◽  
pp. 360-369 ◽  
Author(s):  
Jie Cai ◽  
Qingfeng Guan ◽  
Xiuli Hou ◽  
Zhiping Wang ◽  
Jingxin Su ◽  
...  
Keyword(s):  
Electron Beam ◽  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Isothermal Oxidation ◽  
Oxidation Behaviour ◽  
Thermal Barrier ◽  
High Current ◽  
Barrier Coatings ◽  
Pulsed Electron Beam

scholarly journals Isothermal Oxidation Behavior of Gadolinium Zirconate (Gd2Zr2O7) Thermal Barrier Coatings (TBCs) produced by Electron Beam Physical Vapor Deposition (EB-PVD) technique

2018 ◽  
Vol 16 (1) ◽  
pp. 986-991 ◽  
Author(s):  
Kadir Mert Doleker ◽  
Yasin Ozgurluk ◽  
Hayrettin Ahlatci ◽  
Abdullah Cahit Karaoglanli
Keyword(s):  
Electron Beam ◽  
Thermal Barrier Coatings ◽  
Vapor Deposition ◽  
Bond Coat ◽  
Physical Vapor Deposition ◽  
Isothermal Oxidation ◽  
Atmospheric Plasma ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
X Ray

AbstractThermal Barrier Coatings (TBCs) provide thermal insulation for gas turbine components operating at high temperatures. Generally, TBCs were produced on a MCrAlY bond coat with 7-8% Yttria Stabilized Zirconia (YSZ) using Atmospheric Plasma Spray (APS) technique. In this study, Inconel 718 substrate material was coated with CoNiCrAlY bond coat using high velocity oxygen fuel (HVOF) technique. Afterward, Gd2Zr2O7 was deposited on samples using Electron Beam Physical Vapor Deposition (EB-PVD) technique. Produced TBCs were exposed to isothermal oxidation tests at 1000°C for 8 h, 24 h, 50 h and 100 h in muffle furnace. Scanning electron microscopy-energy distribution X-ray (SEM-EDX) spectroscopy was used to investigate thermally grown oxide (TGO) layer and TGO growth behavior of TBCs. In addition, X-ray Diffractometer (XRD) analysis was performed to TBCs to understand whether phase transformation occurs or not before and after oxidation.

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.

NONDESTRUCTIVE IMPEDANCE SPECTROSCOPY EVALUATION OF THE BOND COAT OXIDATION IN THERMAL BARRIER COATINGS

2007 ◽  
Vol 14 (05) ◽  
pp. 935-943 ◽  
Author(s):  
L. YANG ◽  
Y. C. ZHOU ◽  
W. G. MAO ◽  
Q. X. LIU
Keyword(s):  
Impedance Spectroscopy ◽  
Thermal Barrier Coatings ◽  
Bond Coat ◽  
Equivalent Circuit Model ◽  
Isothermal Oxidation ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Plasma Sprayed

In this paper, the impedance spectroscopy technique was employed to examine nondestructively the isothermal oxidation of air plasma sprayed (APS) thermal barrier coatings (TBCs) in air at 800°C. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were also used to characterize the microstructure evolution of TBCs. After oxidation, the thermally grown oxide (TGO), which was mainly composed of alumina as confirmed by EDX, formed at the upper ceramic coat/bond coat interface, the lower bond coat/substrate interface, and the bond coat. Impedance diagrams obtained from impedance measurements at room temperature were analyzed according to the equivalent circuit model proposed for the TBCs. Various observed electrical responses relating to the growth of oxides and the sintering of YSZ were explained by simulating the impedance spectra of the TBCs.

scholarly journals Enhancing the Oxidation Resistance of NiCrAlY Bond Coat by High-Current Pulsed Electron Beam Irradiation

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 912
Author(s):  
Xianxiu Mei ◽  
Xiaonan Zhang ◽  
Lisong Zhang ◽  
Na Li ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Oxidation Resistance ◽  
Thermal Barrier Coating ◽  
Bond Coat ◽  
Electron Beam Irradiation ◽  
Thermal Barrier ◽  
High Current ◽  
Beam Irradiation ◽  
Pulsed Electron Beam ◽  
Barrier Coating

The bond coat of a NiCrAlY thermal barrier coating plays an important role in solving the thermal expansion mismatch between a metal matrix and a ceramic layer and in improving the oxidation resistance of the whole thermal barrier coating. However, the NiCrAlY bond coat prepared by low-pressure plasma spraying is not conducive to its oxidation resistance because its lamellar structure is loose, porous and the surface is rough. To improve the oxidation resistance of the bond coat, the NiCrAlY bond coat prepared by plasma spraying was modified by high-current pulsed electron beam with different energy densities. Under the electron beam irradiation, the surface of the coating became smooth, and there was a 3–5 μm thick remelting layer on the surface. Under the irradiation, the thickness of the thermal growth oxide layer decreased, and the oxidation resistance was significantly improved, the oxidation product being mainly Al2O3.

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