Фазовая диаграмма системы Ba-Li

К оглавлению: Другие диаграммы (Others phase diargams)

Ba-Li (Barium-Lithium) A.D. Pelton Only one study of the phase diagram of the Li-Ba system has been reported [ 58Kel]. The assessed phase diagram is based primarily on this work. Liquidus points and eutectic and peritectic temperatures were measured by thermal analysis in steel crucibles. A eutectic at 10.5 at.% Ba at 143 C and a peritectic at 18.4 at.% Ba at 156 C were found. The peritectic is associated with the incongruently melting compound Li4Ba, identified by X-ray diffraction. X-ray studies showed no solubility in any of the three solid phases at ambient temperature. These studies were made over the composition range of 1 to 99.6 wt.% Ba, which places the upper limit of solubility of Ba in (Li) at 1 wt.% Ba (0.05 at.% Ba) and of Li in (Ba) at 0.6 wt.% Li at 25 C. However, 0.6 wt.% Li is the same as 10.7 at.% Li. Thus, on an atomic percent basis, an appreciable solubility of Li in (Ba) has not been ruled out. The liquidus was calculated from thermodynamic analysis. It reproduces the liquidus of [58Kel] to within с0.5 to 1.0 wt.%, which is the accuracy with which points could be read from the small weight percent diagram of [58Kel]. No tabulation of data was given by these authors. Because of the very large difference in the atomic weights of Li and Ba, therefore, most experimental points on the Ba liquidus could only be read to с5 to 10 at.%. Under the assumption of no solid solubility, a subregular expression for the excess Gibbs energy of the liquid phase was chosen so that the calculated Li liquidus passes exactly through the reported eutectic point and so that the calculated Ba liquidus passes exactly through the reported peritectic point. 58Kel: D.V. Keller, F.A. Kanda, and A.J. King, J. Phys. Chem., 62, 732-733 ( 1958). Published in Bull. Alloy Phase Diagrams, 5(5), Oct 1984. Complete evaluation contains 2 figures, 1 table, and 6 references. 1