Dioxide--trioxide region of the vanadium--tungsten--oxygen system. [1373/sup 0/K]

Journal Article · Thu Jan 01 00:00:00 EST 1976 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(76)90015-3· OSTI ID:7365465

Ekstroem, T ^[1]; Tilley, R J.D.

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1. Univ. of Stockholm

The phases existing at 1373/sup 0/K in the ternary vanadium--tungsten--oxygen system between the compounds WO/sub 3/, WO/sub 2/, VO/sub 2/, and V/sub 2/O/sub 5/ were characterized by x-ray diffraction and electron microscopy. In the region close to WO/sub 3/, no evidence of substantial substitution of vanadium into the tungsten trioxide structure was found and extensive formation of ternary CS phases was not found. In samples heated for 14 days, the major ternary phase observed was a rutile phase (V,W)O/sub 2/, although some other less stable ternary compounds were also recorded in the V/sub 2/O/sub 5/ rich region of the phase field. Besides these, an orthorhombic modification of tungsten trioxide was found coexisting with the usual monoclinic form, disordered W/sub n/O/sub 3n-1/ (102) crystallographic shear phases and the binary oxide W/sub 18/O/sub 49/. These results are summarized in a phase diagram. Samples heated for short periods of time contained, in addition to the compounds listed above, another unidentified phase and disordered W/sub n/O/sub 3n-2/ (103) crystallographic shear phases. A comparison of both sets of results allows a possible mechanism to be put forward for the reaction between the original tungsten and vanadium oxides. (auth)

• OSTI ID: 7365465
• Journal Information: J. Solid State Chem.; (United States), Vol. 16:1-2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
TUNGSTEN OXIDES
PHASE STUDIES
VANADIUM OXIDES
ELECTRON MICROSCOPY
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
SCATTERING
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
VANADIUM COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies