THE APPEARANCE OF DIFFERENT ORDERED STATES IN REFRACTORY NON-STOICHIOMETRIC PHASES

Journal Article · Mon Jan 01 04:00:00 EST 1962 · Bull. soc. chim. France

OSTI ID:4840132

Collongues, R; Lefevre, J; Jorba, M P.Y.; Queyroux, F

Systems of refractory oxides often have extended nonstoichiometric phases. During conventional thermal treatment, the arrangement of point faults (substitutions or holes) can be modified and new structures appear. In the ZrO/ sub 2/-GeO/sub 2/ system, two intermediate phases with very similar structures appear, one being derived from Zr/sub 3/GeO/sub 8/ and the other from ZrGeO/sub 4/ . These two phases can be considered as superstructures of the type A/sub 3/B and AB of the same disordered solution extending from ZrO/sub 2/ to ZrGeO/sub 4/. In ZrO/sub 2/-rare earth oxide systems, a very extended disorder lacunose solid solution appears at high temperature. For the usual compositions, variable according to the ionic radius of the rare earth compound, the distributions of cations and of holes can be ordered and different superstructures can appear. The most important corresponds to the formation of a superstructure of the pyrochlore type with the general formula Zr/sub 2/M/sub 2/O/sub 7/. Its principal properties are described and the extent of its region of homogeneity is interpretated on the basis of simple geometric considerations. (tr-auth)

• Research Organization: Centre National de la Recherche Scientifique, Paris
• NSA Number: NSA-16-019383
• OSTI ID: 4840132
• Journal Information: Bull. soc. chim. France, Journal Name: Bull. soc. chim. France Vol. Vol: No. 1
• Country of Publication: Country unknown/Code not available
• Language: French

Related Subjects

CATIONS
COMPOUNDS
CONFIGURATION
DEFECTS
DISTRIBUTION
GERMANIUM OXIDES
HEAT TREATMENTS
HIGH TEMPERATURE
HOMOGENEOUS REACTORS
IONS
LATTICES
METALS, CERAMICS, AND OTHER MATERIALS
OXIDES
PHASE DIAGRAMS
RARE EARTHS
REFRACTORIES
SOLID SOLUTIONS
URANIUM MINERALS
VARIATIONS
ZIRCONIUM OXIDES
ZONES