Equilibrium Relations Involving Transition-Metal Oxides at High Temperatures

  • Arnulf Muan

Abstract

Equilibrium relations in oxide systems involving transition metals as components are discussed in terms of phase diagrams and thermo-dynamic properties of individual solid-solution phases. It is shown that at high temperatures (~1400°–1700°C) and very low oxygen pressures \(({{P}_{{{{O}_{2}}}}}\sim {{10}^{{ - 10}}} - {{10}^{{ - 13}}}atm)\) the constituent transition-metal ions occur in unusual oxidation states and that, consequently, the chemistry and the phase relations under these conditions differ dramatically from those prevailing in air. Systems containing chromium oxide or titanium oxide are used as examples, and some general conclusions are drawn. Finally, projections of future directions of research in this area are presented.

Keywords

Phase Relation Oxygen Pressure Equilibrium Relation Chromium Oxide Oxide Solid Solution 
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Copyright information

© Elsevier Science Publishers Ltd 1990

Authors and Affiliations

  • Arnulf Muan
    • 1
  1. 1.Department of GeosciencesThe Pennsylvania State UniversityUSA

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