HOT CORROSION BEHAVIOR OF A (NiCoCrAlYSiB+AlSiY) COMPOSITE COATING
LU Xuyang, YU Daqian, JIANG Sumeng, LIU Shanchuan, GONG Jun, SUN Chao
State Key Laboratory for Corrosion and Protection, Institute of Metal Research, Chinese Academy of Sciences,Shenyang 110016
Cite this article:
LU Xuyang, YU Daqian, JIANG Sumeng, LIU Shanchuan, GONG Jun, SUN Chao. HOT CORROSION BEHAVIOR OF A (NiCoCrAlYSiB+AlSiY) COMPOSITE COATING. Acta Metall Sin, 2012, 48(4): 461-468.
Abstract Two kinds of the coatings, the conventional NiCoCrAlYSiB coating and the composite coating (NiCoCrAlYSiB+AlSiY), were prepared using arc ion plating (AIP) on the Ni base single crystal superalloy substrate. Comparative studies of the hot corrosion behaviors of the substrate and two different coatings in Na2SO4 + K2SO4 and Na2SO4 + NaCl at 900 and 700 ℃ were investigated. The results showed that, during the hot corrosion at 900 ℃, NiO was formed on the surface of the substrate while Cr2O3 was formed on the surface of the conventional coating with the formation of internal oxidation and sulfidation, and Al2O3 was formed on the surface of the composite coating. Slighter internal oxidation appeared in the outer layer of the composite coating. The composite coating contained sufficient Al reservoirs to supply the formation and repair of Al2O3. During the hot corrosion at 700 ℃, NiO was formed on the surface of the substrate and Cr2O3 was formed on the surface of the conventional coating with severe internal oxidation, while internal oxidation appeared in the outer layer of the composite coating. The Cr-enriched inner layer did not suffer from corrosion damage, which can improve the corrosion resistance of the composite coating.