A thermodynamic study of the molybdenum-oxygen system

Journal Article · Thu Dec 01 00:00:00 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), Vol. 25:6; ISSN 0360-2141
• Country of Publication: United States
• Language: English

Related Subjects

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