Oxygen vacancies in Nb/sub 22/O/sub 54-x/, Nb/sub 25/O/sub 62-x/, and Nb/sub 28/O/sub 70-x/
Journal Article
·
· J. Solid State Chem.; (United States)
Isolated oxygen vacancies in Nb/sub 22/O/sub 54-x/, Nb/sub 25/O/sub 62-x/ and Nb/sub 28/O/sub 70-x/ at temperatures above 1300/sup 0/C were examined thermodynamically using gravimetric data obtained previously by Kimura. The concentrations of oxygen vacancies in Nb/sub 22/O/sub 54-x/ and Nb/sub 25/O/sub 62-x/ were estimated from isothermal changes in weight and found to be proportional to Po/sub 2//sup -1///sup 2/. With Nb/sub 28/O/sub 70-x/, on the other hand, the concentration of oxygen vacancies was proportional to Po/sub 2//sup -1///sup 4/. These results can be explained well on the assumption that the main defects, which all depend upon the partial pressure of oxygen in the surrounding atmosphere, are oxygen vacancies with one trapped electron, quasi-free electrons, and tetravalent niobium ions. 6 figures, 2 tables, 24 references. (auth)
- Research Organization:
- National Inst. for Researches in Inorganic Materials, Ibaraki, Japan
- OSTI ID:
- 7355384
- Journal Information:
- J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 16:3; ISSN JSSCB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CRYOGENIC FLUIDS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELEMENTS
FLUIDS
GRAVIMETRIC ANALYSIS
NIOBIUM COMPOUNDS
NIOBIUM OXIDES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
POINT DEFECTS
PRESSURE DEPENDENCE
QUANTITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
TRANSITION ELEMENT COMPOUNDS
VACANCIES
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CRYOGENIC FLUIDS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELEMENTS
FLUIDS
GRAVIMETRIC ANALYSIS
NIOBIUM COMPOUNDS
NIOBIUM OXIDES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
POINT DEFECTS
PRESSURE DEPENDENCE
QUANTITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
TRANSITION ELEMENT COMPOUNDS
VACANCIES