| Title |
Hot Corrosion of NiCrAlY/(ZrO2-Y2O3) Heat Resistant Composite Coatings for Gas Turbines |
| Authors |
이재호(Jae ho Lee); 이창희(Chang Hee Lee); 이동복(Dong Bok Lee) |
| DOI |
https://doi.org/10.3365/KJMM.2010.48.06.506 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
composites; plasma spray; corrosion; scanning electron microscopy; SEM; NiCrAlY |
| Abstract |
The composite coatings of (ZrO2-8Y2O3)/(Ni-22Cr-10Al-1Y) were prepared by the air plasma spraying method. They consisted of (Ni,Cr)-rich regions,(ZrO2-Y2O3)-rich regions, and Al2O3-rich regions that were formed by oxidation of Al from (Ni-22Cr-10Al-1Y) during spraying. The coatings corroded at 800 and 900℃ in NaCl-Na2SO4 molten salts up to 50 hr. Ni, Cr and Al oxidized to NiO, Cr2O3 and α-Al2O3, respectively. These oxides and (ZrO2-Y2O3) 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 Cr2O3, which was most frequently found as surface scales. Aluminum retained in the (Ni,Cr)-rich regions were similarly diffused out. |