SOME PHASE RELATIONS OF THE BaO-UO$sub 2$-O$sub 2$ SYSTEM
To establish the phase relations of the BaO - UO/sub 2/ system, mixtures of BaCO/sub 3/ and UO/sub 2/ in different proportions were heated at 1200 deg C in hydrogen and then examined by x-ray powder methods. Up to 50 mole% BaO there exists a heterogeneous phase region composed of UO/sub 2/ of the fluorite structure and of BaUO/sub 3/ representing the pseudocubic perovskite structure without alteration of their lattice constants, which indicates the lack of solid solutions. Between 50 and 75 mole% Qa0, the samples are homogenous and the elementary cell of BaUO/sub 3/ changes from pseudocubic to cubic, finally exposing new superstructure lines. This points to a continuous transition from the simple perovskite cell to the face-centered of the (NH/sub 4/)/sub 3/FeF/sub 6/ type. Samples containing more than 75 mole% BaO decompose during the heating offering free BaO content. BaUO/sub 3/ oxidizes itself at room temperature with gradual decreasing lattice constant from 4.401 kX at BaUO/sub 3.o/ to 4.383 kX at BaUO/sub 3.3//sub 6/. Fr om the density measurements of the oxidized samples, the formation of an interstitial solution of the oxygen in the BaUO/sub 3/ lattice is expected. At higher oxygen content BaUO/sub 4/ appears. (auth)
- Research Organization:
- Technical Univ., Wroclaw, Poland
- NSA Number:
- NSA-15-009481
- OSTI ID:
- 4097486
- Journal Information:
- Nukleonika (Poland), Journal Name: Nukleonika (Poland) Vol. Vol: 5; ISSN NUKLA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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BARIUM CARBONATES
BARIUM OXIDES
CALCIUM FLUORIDES
CALCIUM OXIDES
CONFIGURATION
DECOMPOSITION
DEFECTS
DENSITY
FLUORIDES
FLUORITE
HIGH TEMPERATURE
HYDROGEN
INTERSTITIALS
IRON FLUORIDES
LATTICES
MEASURED VALUES
METALS, CERAMICS, AND OTHER MATERIALS
MINERALS
MIXING
OXYGEN
PEROVSKITE
PHASE DIAGRAMS
POWDERS
SAMPLING
SOLID SOLUTIONS
STANDARDS
TEMPERATURE
TITANIUM OXIDES
URANATES
URANIUM DIOXIDE
X RADIATION