Accession Number : ADA258055


Title :   X-Ray Diffraction and Electron Microscope Studies of Yttria Stabilized Zirconia (YSZ) Ceramic Coatings Exposed to Vanadia.


Descriptive Note : Master's thesis


Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA


Personal Author(s) : Kondos, Kostandinos G


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a258055.pdf


Report Date : Sep 1992


Pagination or Media Count : 52


Abstract : 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) witch is used as a thermal barrier coating on gas turbine blades can be severely attacked by vanadia. Powders of YSZ containing 8-mol% Y203 and pure zirconia containing various and mounts Of V205 were annealed at 900 deg. C. These were then examined by X-ray diffraction and electron microscopy, as well as single crystals of pure ZrO2 and YSZ (20% Wt Y203) exposed to V205 Melts, to study how the vanadia degrades the YSZ by reacting with the stabilizer to form YVO4 and how the vanadium transforms the cubic and tetragonal YSZ crystal structures to monoclinic which degrades rapidly as a gas turbine blade coating.


Descriptors :   *ANNEALING , *DEGRADATION , *SINGLE CRYSTALS , *ELECTRON MICROSCOPY , *GAS TURBINE BLADES , *X RAY DIFFRACTION , *CERAMIC MATERIALS , *FUELS , *VANADIUM , *BARRIER COATINGS , *THERMAL INSULATION , *ZIRCONIUM OXIDES , *YTTRIUM OXIDES , LOW COSTS , POWDERS , GAS TURBINES , DIFFRACTION , SULFUR , CRYSTALS , MELTS


Subject Categories : Ceramics, Refractories and Glass
      Coatings, Colorants and Finishes
      Metallurgy and Metallography
      Properties of Metals and Alloys
      Test Facilities, Equipment and Methods
      Fuels
      Jet and Gas Turbine Engines


Distribution Statement : APPROVED FOR PUBLIC RELEASE