Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Oxygen solubility and a criterion for the transition from internal to external oxidation of ternary alloys

Journal Article · · Oxidation of Metals
OSTI ID:96435
;  [1]
  1. McMaster Univ., Hamilton, Ontario (Canada)
Smith`s model is expanded in order to derive expressions to quantitatively describe the oxygen-solubility behavior in ternary alloys as a function of alloy composition. Multicomponent-diffusion theory is used to establish a criterion for the onset of internal oxidation beneath the external scale when oxidizing conditions favor formation of the oxide of the least-noble metal in a ternary alloy. The oxygen-solubility model and the criterion are applied to the oxidation of Ni-Cr-Al alloys in 76 torr of oxygen at 1100 and 1200{degrees}C, predicting the minimum Al concentrations required to form a protective Al{sub 2}O{sub 3} scale. It shows that sufficient Cr additions would significantly reduce the oxygen solubility and also alter the oxygen distribution in the ternary alloys, avoiding the oxygen supersaturation necessary for the onset of internal oxidation. These two factors make it easier to establish the protective Al{sub 2}O{sub 3} scale.
OSTI ID:
96435
Journal Information:
Oxidation of Metals, Journal Name: Oxidation of Metals Journal Issue: 5-6 Vol. 42; ISSN OXMEAF; ISSN 0030-770X
Country of Publication:
United States
Language:
English