Alloy/Oxide Equilibria in Iron--Vanadium--Oxygen and Iron--Niobium--Oxygen Systems

Jacob, KT and Kumar, BV (1987) Alloy/Oxide Equilibria in Iron--Vanadium--Oxygen and Iron--Niobium--Oxygen Systems. In: Steel Research, 58 (2). pp. 71-76.

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Abstract

An experimental characterization of three-phase equilibria in Fe--V--O and Fe--Nb--O systems at 1823, 1873 and 1923K has been carried out using a solid state cell and by analysis of quenched samples. The oxygen potentials corresponding to these three-phase equilibria were monitored by a solid state cell incorporating Y sub 2 O sub 3 doped ThO sub 2 with Cr + Cr sub 2 O sub 3 as reference electrode. Similar measurements were carried out for Fe--Nb--O alloys in equilibrium with a mixture of FeNb sub 2 O sub 6 and NbO sub 2 . These measurements permit evaluation of interaction parameters (e exp V sub O = --6590/T + 2.892 and e exp Nb sub O = --4066/T + 1.502) and activity coefficients of vanadiun and niobium in dilute solution (ln gamma exp O sub V = --35 320/T + 12.68 and ln gamma sub Nb exp O = --12 386/T + 4.34) in liquid iron. The results obtained in this study resolve a number of discrepancies in thermodynamic data reported in the literature, especially regarding the activity coefficients of V and Nb and the stability ranges for V sub 2 O sub 3 and VO sub 1+x . 18 ref.--AA

Item Type:	Journal Article
Publication:	Steel Research
Publisher:	Verlag Stahleisen MBH
Additional Information:	Copyright of this article belongs to Verlag Stahleisen MBH.
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	08 Dec 2011 06:31
Last Modified:	08 Dec 2011 06:31
URI:	http://eprints.iisc.ac.in/id/eprint/42584

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