Фазовая диаграмма системы Bi-Ce

К оглавлению: Другие диаграммы (Others phase diargams)


Bi-Ce (Bismuth-Cerium) K.A. Gschneidner, Jr. and F.W. Calderwood The assessed Ce-Bi phase diagram is based on the work of [13Vog], [59Ple], and [75Yos]. The Ce-rich compound, Ce2Bi, forms peritectically above the melting point of Ce and below the incongruent melting point of Ce5Bi3, which is the next intermediate compound in this system. Ce2Bi has a tetragonal structure of the La2Sb-type. Ce5Bi3 has the hexagonal Mn5Si3-type structure. The peritectic temperature is near 1300 C for Ce5Bi3. The temperature horizontal for this reaction, as well as the horizontal for the Ce2Bi decomposition and the liquidus line for this section of the diagram, is drawn with dashed lines to indicate uncertainty. The only compound in the Ce-Bi system that melts congruently is Ce4Bi3, which melts at ~1740 C. The adjacent compound, CeBi, melts incongruently at ~1630 C. Ce4Bi3 has a cubic structure of the anti-Th3P4-type. CeBi has a cubic structure of the NaCl-type. The Bi-rich compound in this system is CeBi2, which decomposes at 910 C to CeBi and the melt. This phase is reported to be triclinic, which appears to be a distorted version of the anti-La2Sb-type structure. The solid solubility of Ce in (Bi) is extremely small, with no apparent effect on the melting point of Bi [59Ple]. In the other RE-Bi systems, Bi lowers the melting point of the rare earth by a eutectic reaction, but the lowering varies from 40 to 140 C, and the eutectic composition varies from 3.2 to 22.5 at.%. This wide variation makes it difficult to estimate the appropriate values for the Ce-Bi system. Consequently, the Ce-rich portion of the assessed diagram has been drawn with dashed lines to reflect this uncertainty. Additions of Bi are expected to have little effect on the g = d phase transformation of pure Ce, which occurs at 726 C. Averaged data from [61Sch] and [71Kob] indicate that 0.02 at.% Ce is soluble in Bi at 300 C and 0.74 at.% at 600 C. 13Vog: R. Vogel, Z. Anorg. Chem., 84, 323 (1913). 59Ple: R.J. Pleasance, J. Inst. Met., 88, 45 (1959-60). 61Sch: D.G. Schweitzer and J.R. Weeks, Trans. Quart., 54, 185 (1961). 71Kob: V.I. Kober, V.A. Lebedev, I.F. Hichkov, and S.P. Raspopin, Zh. Fiz. Khim., 45, 569 (1971); TR: Russ. J. Phys. Chem., 45, 313 (1971). 75Yos: K. Yoshihara, J.B. Taylor, L.D. Calvert, and J.G. Despault, J. Less- Common Met., 41, 329 (1975). Published in Bull. Alloy Phase Diagrams, 9(4), Aug 1988. Complete evaluation contains 1 figure, 1 table, and 30 references. 1