Phase relationships in the system Cr-W-O and thermodynamic properties of CrWO4 and Cr2WO6

Jacob, K. T. (1980) Phase relationships in the system Cr-W-O and thermodynamic properties of CrWO4 and Cr2WO6 Journal of Materials Science, 15 (9). pp. 2167-2174. ISSN 0022-2461

[img]
Preview
PDF - Publisher Version
484kB

Official URL: http://www.springerlink.com/content/k12h156444325j...

Related URL: http://dx.doi.org/10.1007/BF00552303

Abstract

The phase diagram of the Cr-W-O system at 1000 ° C was established by metallographic and X-ray identification of the phases present after equilibration in evacuated silica capsules. Two ternary oxide phases, CrWO4 and Cr2WO6 were detected. The oxygen potential over the three-phase mixtures, W+Cr2O3 s+CrWO4, WO2.90+CrWO4+Cr2WO6 and Cr2O3+CrWO4+Cr2WO6, were measured by solid state cells incorporating Y2O3 stabilized ZrO2 electrolyte and Ni+NiO reference electrode. The Gibbs' energies of formation of the two ternary phases can be represented by the following equations W(s) + ½Cr203(s) + 5/4 02(g) → CrWO4(s). ΔG° =- 172 047 + 48.725T(±230) cal mo1-1. Cr203 (s) + WO3(s) → Cr2WO6 (s). ΔG± = -3 835 + 0.235T(±500) cal mol-1.

Item Type:Article
Source:Copyright of this article belongs to Springer-Verlag.
ID Code:12993
Deposited On:11 Nov 2010 07:07
Last Modified:16 May 2016 22:14

Repository Staff Only: item control page