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The ternary system uranium-boron-carbon
Phase equilibria in the ternary system U-B-C have been established by means of X-ray, metallographic and melting point analyses in the temperature range from 1000 ° C to melting. Three ternary compounds were found to exist: besides the well known monoboroncarbide UBC two new uranium boroncarbides, U...
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Published in: | Journal of nuclear materials 1989-04, Vol.165 (1), p.74-82 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Phase equilibria in the ternary system U-B-C have been established by means of X-ray, metallographic and melting point analyses in the temperature range from 1000 ° C to melting. Three ternary compounds were found to exist: besides the well known monoboroncarbide UBC two new uranium boroncarbides, UB
2C and “U
5B
2C
7”. Ternary phase equilibria are characterized by the incompatibility of uranium metal with boroncarbide B
4C and by the incompatibility of elemental boron and uranium carbides; an isothermal section of the system U-B-C at 1600° C is presented.
At high temperatures the crystal structure of UB
2C was found to be isotypic with the homologous compound ThB
2C; at temperatures below (1675 ± 25)°C h-UB
2C transforms into a low temperature modification with a new (unknown) structure type. The crystal structure of “U
5B
2C
7” is closely related to the structure type of Ho
5B
2C
6−7 as a derivative of La
5
2C
6 Employing the Pirani-technique, congruent melting was revealed for UBC and UB
2C at (2144 ± 25)°C and (2282 ± 30)°C respectively. Using the clear-cross principle in studying possible phase reactions, the thermodynamic stabilities of UBC, UB
2C and U
5B
2C
7 were estimated. |
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ISSN: | 0022-3115 1873-4820 |
DOI: | 10.1016/0022-3115(89)90504-7 |