Oxidation and Hot Corrosion of Ni-Cr- and Co-Cr-Base Alloys Containing Rare Earth Oxide Dispersions

The effects of rare earth oxide (REO) dispersions, Y2O3, and CeO2, on the oxidation and hot corrosion characteristics and mechanisms of Ni-Cr- and Co-Cr-base alloys were studied. Primary emphasis was directed toward a detailed investigation of Ni-20w/oCr-3v/o REO and Co-21w/oCr-3v/o REO alloys prepa...

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Bibliographic Details
Main Authors: Stringer,John, Wright,Ian G, Wilcox,Ben A, Jaffee,Robert I
Format: Report
Language:English
Subjects:
COBALT ALLOYS
CORROSION
HEAT RESISTANT ALLOYS
HEAT RESISTANT METALS
OXIDATION
Properties of Metals and Alloys
RARE EARTH ELEMENTS
SUPERALLOYS
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Summary:The effects of rare earth oxide (REO) dispersions, Y2O3, and CeO2, on the oxidation and hot corrosion characteristics and mechanisms of Ni-Cr- and Co-Cr-base alloys were studied. Primary emphasis was directed toward a detailed investigation of Ni-20w/oCr-3v/o REO and Co-21w/oCr-3v/o REO alloys prepared by attritor milling, and preliminary oxidation results were obtained on Co-Cr-Al-Y2O3 alloys. It was found that REO particles had four effects on the oxidation behavior of Ni-Cr and Co-Cr alloys: (1) They promote the selective oxidation of chromium to form a continuous protective Cr2O3 scale; (2) The rate of growth of Cr2O3 is reduced compared with particle-free alloys; (3) Cr2O3 oxide scale growth is inward in dispersion alloys compared with outward growth in particle-free alloys; (4) Oxide scale adhesion is improved. A kinetic analysis was developed to account for the oxidation behavior and a model of scale growth is presented. (Author)