Yttrium segregation and YAG precipitation at surfaces of yttrium-doped. cap alpha. -Al/sub 2/O/sub 3/

Journal Article · Fri Aug 01 04:00:00 EDT 1986 · J. Am. Ceram. Soc.; (United States)

OSTI ID:7194976

McCune, R C; Donlon, W T; Ku, R C

Auger electron spectroscopy and low-energy ion scattering were used to assess surface composition of yttrium-doped polycrystalline and single-crystal ..cap alpha..-aluminas which were heated under vacuum to temperatures above 1500/sup 0/C. Extensive surface and intergranular precipitation of yttrium aluminum garnet was observed in a compact of nominal Y content of 210 wt ppm, while apparent Y segregation to surface cation sites predominated in a second compact with a Y content of 160 wt ppm. In the latter case, the segregation enthalpy of yttrium to the alumina surface in the temperature range 1700/sup 0/ to 1900/sup 0/C was estimated to be of the order -44 kJ/mol with a maximum surface cation site occupancy of approx. =13%.

• Research Organization: Research Staff, Ford Motor Co., Dearborn, MI 48121-2053
• OSTI ID: 7194976
• Journal Information: J. Am. Ceram. Soc.; (United States), Journal Name: J. Am. Ceram. Soc.; (United States) Vol. 69:8; ISSN JACTA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AUGER ELECTRON SPECTROSCOPY
CHALCOGENIDES
CHARGED PARTICLES
CRYSTAL DOPING
CRYSTALS
DOPED MATERIALS
ELECTRON SPECTROSCOPY
ELEMENTS
ENTHALPY
FERRITE GARNETS
HEATING
IONS
MATERIALS
METALS
MINERALS
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLYCRYSTALS
PRECIPITATION
SCATTERING
SEGREGATION
SEPARATION PROCESSES
SILICATE MINERALS
SPECTROSCOPY
SURFACE PROPERTIES
SURFACES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VERY HIGH TEMPERATURE
YTTRIUM
YTTRIUM COMPOUNDS