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| Abstract No.: |
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Scheduled at:
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Tuesday, May 04, 2010, Hullet Room 5:00 PM
Cold Spraying 4
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| Title: |
Effects of surface morphology of MCrAlY bond coat on the isothermal oxidation and thermal fatigue behavior of thermal barrier coatings
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| Authors: |
Chang-Jiu Li / Xi'an Jiaotong University, P.R. China
Yong Li* / School of Materials Science and Engineering, Xi'an Jiaotong University, P.R.China
Lu-Kuo Xing/ School of Materials Science and Engineering, Xi'an Jiaotong University, P.R.China
Guan-Jun Yang/ School of Materials Science and Engineering, Xi'an Jiaotong University, P.R.China
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| Abstract: |
Cold sprayed alloy coating is formed through the plastic deformation of alloy particles in solid state, which induces a different surface morphology from that by conventional thermal spraying techniques. In the present study the oxidation of the MCrAlY bond coats with different surface morphologies deposited by both cold spraying and low-pressure plasma spraying (LPPS) and thermal fatigue behavior of thermal barrier coatings (TBCs) were compared. Both of the two as-deposited bond coats exhibited dense microstructure. However, surface morphology of LPPSed MCrAlY bond coat is significantly different from that of cold-sprayed one. The particles on surface of the cold sprayed bond coat showed a smoother surface than that of the LPPSed bond coat which was modified by the splashed splat fragments. The splashed splat fragment attached on the surface of LPPSed bond coat increased the surface area of bond coat and limited its bonding with the underlying coating, which accelerated the depletion of Al element during oxidation and high temperature thermal cyclic test. An Al2O3 film covered by a layer of Ni/Cr rich oxide was formed on the modified surface bond coat deposited by LPPS. Only Al2O3-based TGO was formed on the cold sprayed bond coat. TBCs with a smooth surface bond coat deposited by cold spraying were more resistant to thermal cycling than that with a modified surface bond coat deposited by LPPS, which was due to the less growth of Ni/Cr rich oxides during thermal cycling.
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