A thermodynamic study of the molybdenum-oxygen system

Journal Article · Thu Dec 01 04:00:00 EST 1994 · Metallurgical Transactions, B (Process Metallurgy); (United States)

DOI:https://doi.org/10.1007/BF02662770· OSTI ID:6547154

Bygden, J; Sichen, Du; Seetharaman, S ^[1]

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1. Royal Inst. of Tech., Stockholm (Sweden). Div. of Theoretical Metallurgy

In the present work, the oxygen partial pressures corresponding to Mo/MoO[sub 2] equilibrium were measured by a solid-electrolyte galvanic cell method. The cell used can be represented as ([minus])Pt[vert bar]Fe[sub (s)], FeO[sub (s)][vert bar][vert bar]ZrO[sub 2]-CaO(11 mole pct) or ThO[sub 2]-Y[sub 2]O[sub 3](17.1 mole pct)[vert bar][vert bar]MoO[sub 2(s)], Mo[sub (s)][vert bar]Pt(+). The measurements were carried out in the temperature range of 1,224 to 1,584 K. The electromotive force (EMF) measured is represented by the following equation: E (mV) = 122.02 [minus] 0.09762 [times] T(K) [+-] 2.12. The values are in good agreement with the earlier measurements. Combining these, an optimized expression for the RT ln P[sub O[sub 2]], corresponding to Mo/MoO[sub 2] equilibrium, was arrived at: RT ln P[sub O[sub 2]] (J/mole) = ([minus]580,563 [+-] 916) + (173.0 [+-] 0.72) [times] T(K). This was incorporated along with the thermodynamic information of other phases in the Mo-O system to achieve a complete thermodynamic description of mainly the solid-phase region of this system by a CALPHAD approach.

• OSTI ID: 6547154
• Journal Information: Metallurgical Transactions, B (Process Metallurgy); (United States), Journal Name: Metallurgical Transactions, B (Process Metallurgy); (United States) Vol. 25:6; ISSN MTTBCR; ISSN 0360-2141
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
360606 -- Other Materials-- Physical Properties-- (1992-)
ACTINIDE COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM OXIDES
CALIBRATION STANDARDS
CHALCOGENIDES
ELECTROCHEMICAL CELLS
ELECTROLYTES
ELEMENTS
IRON
IRON COMPOUNDS
IRON OXIDES
MEASURING METHODS
METALS
MOLYBDENUM
MOLYBDENUM COMPOUNDS
MOLYBDENUM OXIDES
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHYSICAL PROPERTIES
PLATINUM
PLATINUM METALS
REFRACTORY METAL COMPOUNDS
SOLID ELECTROLYTES
STANDARDS
THERMODYNAMIC PROPERTIES
THORIUM COMPOUNDS
THORIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES