Korean Journal of Metals and Materials (대한금속재료학회지)

The Korean Institute of Metals and Materials (대한금속재료학회)
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Hot Corrosion of NiCrAlY(ZrO2-Y2O3) Heat Resistant Composite Coatings for Gas Turbines

가스터빈용 NiCrAlY/(ZrO2-Y2O3) 내열복합코팅의 고온 용융염 부식

  • 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)
  • 이재호 (성균관대학교 신소재공학과) ;
  • 이창희 (한양대학교 신소재공학부) ;
  • 이동복 (성균관대학교 신소재공학과)
  • Received : 2010.01.29
  • Published : 2010.06.22
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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

Acknowledgement

Supported by : 기초전력연구원

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