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| Abstract No.: |
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Scheduled at:
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Wednesday, September 28, 2011, Saal A 4:00 PM
Aviation Industry 3
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| Title: |
The protectiveness of alumina scales in thermal barrier coating with cold sprayed bond coating
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| Authors: |
Abreeza Manap* / Department of Mechanical Engineering, Universiti Tenaga Nasional, Malaysia
Kazuhiro Ogawa/ Fracture and Reliability Research Institute, Tohoku University, Japan
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| Abstract: |
This paper presents the results of a study of the oxidation behavior of thermal barrier coating (TBC) with air plasma sprayed (APS) yttria-stabilized zirconia (YSZ) top coat and CoNiCrAlY bond coat deposited using two different spraying techniques, low pressure plasma spray (LPPS) and cold spray (CS). The TBC is subjected to isothermal oxidation and creep tests at 900 °C and evaluated using scanning elctronmicroscopy (SEM), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM). Residual stress in the TGOs is measured using X-ray diffraction (XRD). After 800, the TGO developed in TBC with CS bond coat is composed of gamma-Al2O3 and alpha- Al2O3 and the TGO developed in TBC with LPPS bond coat was composed of only alpha-Al2O3. Despite the presence of this metastable gamma phase that is known to have a high oxide growth rate, the TGO of the CS specimen exhibits favorable behavior; smaller TGO thickness, absence of mixed oxides, lower residual stress. The effects of TGO texture on residual stress generation is discussed. Overall findings indicate that the oxidation behavior of the TBC with CS bond coat is superior compared to that of the TBC with LPPS bond coat.
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