Dioxide--trioxide region of the vanadium--tungsten--oxygen system. [1373/sup 0/K]
- 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), Journal Name: J. Solid State Chem.; (United States) Vol. 16:1-2; ISSN JSSCB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
ELECTRON MICROSCOPY
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
SCATTERING
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
TUNGSTEN OXIDES
VANADIUM COMPOUNDS
VANADIUM OXIDES
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION