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Melting Behavior in the System UO 2 –PuO 2
Author(s) -
CHIKALLA T. D.
Publication year - 1963
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1963.tb11739.x
Subject(s) - liquidus , melting point , oxygen , plutonium , solid solution , helium , materials science , phase diagram , thermodynamics , chemistry , analytical chemistry (journal) , phase (matter) , metallurgy , radiochemistry , alloy , physics , organic chemistry , composite material , chromatography
The melting points of UO 2 and PuO 2 in a helium atmosphere were found to be 2730°× 30° C and 2280°× 30° C, respectively. With the exception of a melting maximum at the composition 90 UO 2 –10 wt% PuO 2 , the liquidus exhibits good continuity and agrees well with that calculated from thermodynamic data. X‐ray diffraction data on melted PuO 2 and UO 2 ‐PuO 2 solid solutions indicate that oxygen is evolved during melting but that no reduction to a second‐phase plutonium suboxide occurs. The oxygen‐plutonium atomic ratio of melted PuO 2 is 1.62, so that the 2280° C temperature reported here is the result of a dissociation reaction and is considered to be a pseudo melting point. Lattice parameters of melted UO 2 –PuO 2 samples vary linearly with composition but are approximately 0.2% greater than anticipated because of an oxygen deficiency.