Oxidation-reduction and the major type of ionic disorder in. cap alpha. -Al/sub 2/O/sub 3/

Journal Article · Sat Oct 01 04:00:00 EDT 1983 · J. Am. Ceram. Soc.; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1983.tb10539.x· OSTI ID:6325534

Kroger, F A

The oxidation-reduction constants of Al/sub 2/O/sub 3/:Ti and Al/sub 2/O/sub 3/ are derived from experimental data on the basis of models with aluminum vacancies or oxygen interstitials as dominant species. Reasonable agreement between the experimental values of the enthalpies involved and published theoretical values are found in both cases. Combination with the enthalpies of oxidation determined from acceptor-doped Al/sub 2/O/sub 3/ leads to values of the enthalpy of disorder for the four possible mechanisms. All agree equally well with computed values. Published microstructure studies point to Frenkel disorder of oxygen as the dominant ionic disorder mechanism. Empirical potentials used in theoretical computations appear to be preferable to nonempirical ones, at least for computations related to oxygen defects.

• Research Organization: Department of Materials Science, University of Southern California, University Park, Los Angeles, California
• OSTI ID: 6325534
• Journal Information: J. Am. Ceram. Soc.; (United States), Journal Name: J. Am. Ceram. Soc.; (United States) Vol. 66:10; ISSN JACTA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELEMENTS
ENTHALPY
INTERSTITIALS
METALS
MICROSTRUCTURE
NONMETALS
ORDER-DISORDER TRANSFORMATIONS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POINT DEFECTS
REDOX POTENTIAL
REDUCTION
THERMODYNAMIC PROPERTIES
TITANIUM ADDITIONS
TITANIUM ALLOYS
VACANCIES