Activity-Composition Relations in Orthosilicate and Metasilicate Solid Solutions in the System MnO-CoO-SiO2

Activity‐composition relations in Mn‐Co orthosilicate and metasilicate solid solutions were determined at 1200° to 1250°C by equilibrating selected phase assemblages with metallic cobalt and a gas phase of known oxygen potentials at a total pressure of 1 atm. The orthosilicate solid solution shows a...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 1967-05, Vol.50 (5), p.230-235
Main Authors: BIGGERS, J. V., MUAN, ARNULF
Format: Article
Language:English
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Summary:Activity‐composition relations in Mn‐Co orthosilicate and metasilicate solid solutions were determined at 1200° to 1250°C by equilibrating selected phase assemblages with metallic cobalt and a gas phase of known oxygen potentials at a total pressure of 1 atm. The orthosilicate solid solution shows a slight negative departure from ideality, whereas the metasilicate solid solution is ideal. The stability data derived for the Mn2SiO4 and MnSiO3 end‐members are in good agreement with those previously determined from the system MnO‐“FeO”‐SiO2. The free‐energy change for the reaction 2CoSiO3= Co2‐SiO4+ SiO2 was determined to be ‐3.8 kcal at 1250°C.
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1151-2916.1967.tb15093.x