Фазовая диаграмма системы Bi-Li

К оглавлению: Другие диаграммы (Others phase diargams)

Bi-Li (Bismuth-Lithium) J. Sangster and A.D. Pelton The assessed phase diagram for the Bi-Li system is based mainly on [34Gru], with review of the data of [64Fos] and [78Wep]. The accuracy of the liquidus shown in the assessed diagram is estimated as с2 degrees for Li content below about 25 at.%, с10 degrees from 25 to 65 at.% Li, and с25 degrees at higher Li content. Solubilities of Li in solid (Bi) and of Bi in solid (Li) have not been reported. The activity coefficient of Bi in liquid alloys with less than 30 at. % Li is nearly unity. If it is assumed that Li is insoluble in solid (Bi), then the liquidus composition at the eutectic temperature of 243 C can be calculated thermodynamically from the enthalpy of fusion as 12.8 at.% Li, in good agreement with the value of 14 at.% Li obtained from extrapolation of the liquidus curves. The solubility of Li in (Bi) is thus expected to be limited to less than 1 or 2 %, as would be expected from the approximately 15% difference in atomic diameters. If it is assumed that Bi is insoluble in solid (Li), then a liquidus composition of 99.0 at.% Li is calculated thermodynamically for a eutectic temperature of 175 C, as shown in the assessed diagram. The results from thermal analysis and electrical conductivity measurements [ 34Gru] indicate that the compounds BiLi and BiLi3 are the only intermediate phases in the system. The emf/coulometric titration measurements [78Wep] at 380 C covered the range 0 to 75 at.% Li and confirm the absence of other phases. X-ray examination of alloys of 7.5, 24.3, 48.6, 63.1, 72.4, 76.2, 78.0, and 82.3 at.% Li [35Zin] identified only the pure elements and the two stoichiometric phases. 34Gru: G. Grube, H. VosskЃhler, and H. Schlecht, Z. Elektrochem., 40(5), 270- 274 (1934) in German. 35Zin: E. Zintl and G. Brauer, Z. Elektrochem., 41(5), 297-303 (1935) in German. 64Fos: M.S. Foster, S.E. Wood, and C.E. Crouthamel, Inorg. Chem., 3(10), 1428- 1431 (1964). 78Wep: W. Weppner and R.A. Huggins, J. Elektrochem. Soc., 125(1) 7-14 (1978). Submitted to the APD Program. Complete evaluation contains 2 figures, 4 tables, and 13 references. Special Points of the Bi-Li System