Vanadia reactions with yttria stabilized zirconia
The reaction of vanadia films with yttria stabilized single-crystal cubic and polycrystalline cubic-tetragonal zirconias was studied using Rutherford backscattering (RBS) and x-ray diffraction, with some selected depth profiling studies. Vandium on zirconia readily oxidizes at 500 /sup 0/C to form vanadia films. With increasing temperature, small amounts of vanadia diffuse into the zirconia. Near 650 /sup 0/C the vanadia forms a eutectic solution at the surface and massive diffusion into the ZrO/sub 2/ occurs. With rapid heating much of the vanadia volatilizes; with slow heating the vanadia diffuses large distances into the zirconia. Near 800 /sup 0/C the vanadia principally reacts with yttria to form yttrium vanadate. At 980 /sup 0/C and above, vanadia is completely reacted. Zirconia coated with materials which do not form a eutectic mixture (tantala, tantalum, vanadium) showed little reaction or diffusion at 900--1000 /sup 0/C, but massive dissolution when a eutectic is formed (vanadia, chromia+vanadia). Yttria preferentially diffuses toward the surface when a reaction takes place to form YVO/sub 4/ . When yttria is sequestered as the vanadate, the zirconia changes phase from cubic to monoclinic. Little difference in reactivity is observed between single-crystal and polycrystalline zirconia due to eutectic solution formation, which, with the phase separation, produces a very corroded surface.
- Research Organization:
- Department of Materials Science and Engineering, Bard Hall, Cornell University, Ithaca, New York 14853
- OSTI ID:
- 5312094
- Journal Information:
- J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 63:11; ISSN JAPIA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALLOYS
CHEMICAL REACTIONS
COHERENT SCATTERING
CRYSTALS
DATA
DIFFRACTION
ELASTIC SCATTERING
ELEMENTS
EXPERIMENTAL DATA
FILMS
HIGH TEMPERATURE
INFORMATION
METALS
MONOCRYSTALS
NUMERICAL DATA
POLYCRYSTALS
RUTHERFORD SCATTERING
SCATTERING
STABILIZATION
THIN FILMS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VANADIUM
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION
YTTRIUM ADDITIONS
YTTRIUM ALLOYS
ZIRCONIUM COMPOUNDS