Characterization of Ni-25 wt.% Cr alloys containing reactive elements and the oxide scales grown on them at high temperatures using transmission electron microscopy
- Oregon Graduate Institute of Science and Technology, Portland, OR (United States)
Nickel-base alloys of nominal composition Ni-25 Wt.% Cr-(0-0.6 Wt.%) RE (RE=Y, La, and Ce) were prepared by conventional arc-melting Ni, Cr, and Y metal. The microstructure of the alloys was characterized by using electron diffraction and X-ray energy dispersive spectroscopy (XEDS) to determine the structure, morphology, and distribution of second-phase particles. Selected alloys were oxidized at 900{degrees}C and 1000{degrees}C in 1-atm air, and the resultant oxide scales were characterized using the same analytical techniques. The experimentally determined electron-diffraction data were compared with a JCPDF-EDD database, and several compounds were matched. The observed phases were RE oxysulfide, cerium orthochromite-CeCrO{sub 3}, yttria-Y{sub 2}O{sub 3}, yttrium orthochromite-YCrO{sub 3}, and Ni{sub 5}Y. The significance of these observations is discussed with respect to the current level of knowledge on the role of sulfur in the reactive-element effect. The ability of the reactive elements to getter sulfur is examined with respect to the thermodynamic stability of the oxysulfide species.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 96456
- Journal Information:
- Oxidation of Metals, Vol. 43, Issue 5-6; Other Information: PBD: Jun 1995
- Country of Publication:
- United States
- Language:
- English
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