High Temperature Oxidation Resistance of Two Ni(Co)CrAlYSi(Hf) Overlay Coatings

Abstract:

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Two MCrAlY overlay coatings (NiCrAlYSi and NiCoCrAlYHf) were deposited on a DS superalloy of Ni-Al-Cr-Co-W-Mo-Ta-Hf system by vacuum arc deposition method. The two coatings show a good protection for the DS superalloy during the isothermal oxidation test at 1150 for 100 h. A continuous alumina-based scale was formed at the surfaces of the coated specimens after oxidation. Y2O3, NiO and SiO2 are also detectable in the oxide scale. For the Hf-bearing coating, some HfO2 particles exist at the interface between the coating and the substrate. But after the cyclic thermal oxidation at 1100°C, the Hf-free coating exhibited better oxidation resisitance than the Hf-bearing coating. The HfO2 blocks between the coat and the substrate may be the crack initiation which leads to the failure of the coating.

Info:

Periodical:

Materials Science Forum (Volumes 539-543)

Main Theme:

Edited by:

T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran

Pages:

1146-1152

DOI:

10.4028/www.scientific.net/MSF.539-543.1146

Citation:

Z. H. Huang et al., "High Temperature Oxidation Resistance of Two Ni(Co)CrAlYSi(Hf) Overlay Coatings", Materials Science Forum, Vols. 539-543, pp. 1146-1152, 2007

Online since:

March 2007

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$35.00

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