X-ray diffraction and electron microscope studies of yttria stabilzed zirconia (YSZ) ceramic coatings exposed to vanadia.

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Author
Kondos, Konstandinos G.
Date
1992-09Advisor
Fox, A.G.
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Show full item recordAbstract
The U.S. Navy sometimes has the requirement to use low cost fuels containing significant
amounts of vanadium and sulfur in gas turbine engines. Unfortunately the yttria stabilized zirconia
(YSZ) which is used as a thermal barrier coating on gas turbine blades can be severely attacked by
vanadia. Powders of YSZ containing 8-mol% Y2 3 and pure zirconia containing various amounts of
V2Os were annealed at 900°C. These were then examined by X-ray diffraction and electron
microscopy, as well as single crystals of pure Zr02 and YSZ ( 20%wt Y2 3 ) exposed to V2 5 melts,
to study how the vanadium degrades the YSZ by reacting with the stabilizer to form YV04 and how
the vanadia transforms the cubic and tetragonal YSZ crystal structures to monoclinic which degrades
rapidly as a gas turbine blade coating.