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Phase Behavior in the Sm‐B System
Author(s) -
SOLOVYEV G. I.,
SPEAR K. E.
Publication year - 1972
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.1151-2916.1972.tb11344.x
Subject(s) - boride , phase diagram , boron , phase (matter) , materials science , lattice constant , analytical chemistry (journal) , diffraction , solid solution , samarium , thermodynamics , mineralogy , chemistry , metallurgy , inorganic chemistry , chromatography , physics , organic chemistry , optics
Phase equilibria in the samarium‐boron system were investigated by X‐ray and metallographic techniques. Melting behavior and temperatures, or limits for these temperatures, were determined and used in constructing a temperature‐composition phase diagram. Four intermediate binary phases were found: SmB x ( x =2.0±0.6), SmB 4 , SmB 6 , and SmB 66 . The tetra‐ and hexaborides were well known, and phases isomorphous with SmB 66 have been reported, but the SmB x phase gives an X‐ray diffraction pattern different from that of any known boride. Lattice constants were calculated for the 3 phases with known structures; the composition dependence of the values for the tetra‐ and hexaborides indicates that both phases have measurable composition ranges. Measured Vickers’microhardness values increase markedly for phases with increasing boron content. The SmB x phase is very soft compared to most boride phases.