Oxygen content of liquid cobalt in equilibrium with CoO.(1+x)Al2O3 and -Al2O3

Jacob, KT and Hajra, JP (1986) Oxygen content of liquid cobalt in equilibrium with CoO.(1+x)Al2O3 and -Al2O3. In: Zeitschrift für Metallkunde, 77 . pp. 673-677.

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Abstract

The oxygen concentration of liquid cobalt in equilibrium with cobalt aluminate and a-alumina has been measured by suction sampling and crucible quenching techniques at temperatures between 1770 and 1975 K. Experiments were made with cobalt of high and low initial oxygen contents, and with and without the addition of cobalt aluminate. The effect of temperature on the equilibrium oxygen content is represented by the equation, log (at.% 0) = -10,4001T(K) + 4.64 (±0.008). The composition of the spinel phase, CoO.(1+x)AI20 3, saturated with alumina, has been determined by electron probe microanalysis. The values of x are 0.22 at 1770 Kand 0.28 at 1975 K. The oxygen potential corresponding to the three-phase equilibrium between cobalt, aluminate and alumina, and the standard Gibbs' energy of formation of nonstoichiometric cobalt aluminate are evaluated by combining the results of this study with recently published data on the activity of oxygen in liquid cobalt. Implications of the present results to aluminium deoxidation of liquid cobalt are discussed.

Item Type:	Journal Article
Publication:	Zeitschrift für Metallkunde
Publisher:	Carl Hanser Verlag
Additional Information:	Copyright of this article belongs to Carl Hanser Verlag.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	07 Dec 2011 10:22
Last Modified:	07 Dec 2011 10:22
URI:	http://eprints.iisc.ac.in/id/eprint/42581

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