| 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. |
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| Key Words |
| composites, plasma spray, corrosion, scanning electron microscopy, SEM, NiCrAlY |
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