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http://dx.doi.org/10.3365/KJMM.2010.48.06.506

Hot Corrosion of NiCrAlY(ZrO2-Y2O3) Heat Resistant Composite Coatings for Gas Turbines  

Lee, Jae Ho (School of Advanced Materials Science and Engineering, Sungkyunkwan University)
Lee, Changhee (Department of Materials Science and Engineering, Hanyang University)
Lee, Dong Bok (School of Advanced Materials Science and Engineering, Sungkyunkwan University)
Publication Information
Korean Journal of Metals and Materials / v.48, no.6, 2010 , pp. 506-513 More about this Journal
Abstract
The composite coatings of $(ZrO_2-8Y_2O_3)$/(Ni-22Cr-10Al-1Y) were prepared by the air plasma spraying method. They consisted of (Ni,Cr)-rich regions,$(ZrO_2-Y_2O_3)$-rich regions, and $Al_2O_3$-rich regions that were formed by oxidation of Al from (Ni-22Cr-10Al-1Y) during spraying. The coatings corroded at 800 and $900^{\circ}C$ in NaCl-$Na_2SO_4$ molten salts up to 50 hr. Ni, Cr and Al oxidized to NiO, $Cr_2O_3$ and ${\alpha}-Al_2O_3$, respectively. These oxides and $(ZrO_2-Y_2O_3)$ were dissolved off into the molten salts during hot corrosion, which resulted in the ever-lasting corrosion of the composite coatings. Chromium diffused out from the (Ni,Cr)-rich regions and oxidized to $Cr_2O_3$, which was most frequently found as surface scales. Aluminum retained in the (Ni,Cr)-rich regions were similarly diffused out.
Keywords
composites; plasma spray; corrosion; scanning electron microscopy (SEM); NiCrAlY;
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Times Cited By KSCI : 3  (Citation Analysis)
Times Cited By SCOPUS : 0
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