Diffusion of oxygen in transition oxides. II. Self-diffusion of oxygen in the suboxide Nb/sub 28/O//sub 70-x/, the closest to Nb/sub 2/O/sub 5/ stoichiometry

Journal Article · Wed Feb 01 04:00:00 EST 1978 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/S0022-4596(78)90186-X· OSTI ID:6745927

Massiani, Y; Crousier, J P; Streiff, R

To take advantage of a new approach to nonstoichiometry in the oxide Nb/sub 2/O/sub 5/, for which there are several phases in the region of nonstoichiometry showing crystallographic shear structures, a study of oxygen self-diffusion by isotopic solid-gas exchange reaction has been undertaken. The self-diffusion coefficient of oxygen in Nb/sub 2/O/sub 5/ has been measured in the range 900 to 1200/sup 0/C for partial pressures of oxygen varying from 0.3 to 3.3 x 10/sup -2/ atmosphere, a region corresponding to existence of the single-phase suboxide Nb/sub 28/O/sub 70/, the closest to Nb/sub 2/O/sub 5/ stoichiometry. Results obtained at 1046, 1100, and 1200/sup 0/C show that D follows a Po/sub 2//sup -/sup 1///sub 4// dependence in the composition range close to stoichiometry and can be interpreted as arising from singly ionized oxygen vacancies.

• Research Organization: Universite de Provence, Marsielle
• OSTI ID: 6745927
• Journal Information: J. Solid State Chem.; (United States), Journal Name: J. Solid State Chem.; (United States) Vol. 24:1; ISSN JSSCB
• Country of Publication: United States
• Language: French

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
CHEMICAL REACTION YIELD
CRYOGENIC FLUIDS
CRYSTAL STRUCTURE
DIFFUSION
ELEMENTS
FLUIDS
ISOTOPIC EXCHANGE
LOW PRESSURE
MECHANICAL PROPERTIES
NIOBIUM COMPOUNDS
NIOBIUM OXIDES
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PRESSURE DEPENDENCE
SELF-DIFFUSION
SHEAR PROPERTIES
STOICHIOMETRY
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
VERY HIGH TEMPERATURE
YIELDS