Фазовая диаграмма системы Ba-Na

К оглавлению: Другие диаграммы (Others phase diargams)

Ba-Na (Barium-Sodium) A.D. Pelton The assessed phase diagram for the Na-Ba system is based on the work of [65Kan] and [71Add], which are in reasonable agreement above 28 at.% Ba. For Ba content less than 28 at.%, the data of [71Add] are preferred. There is one eutectic at 83 C and 4.5 at.% Ba. Two intermediate compounds were identified: Na4Ba, with a peritectiod reaction at 70 C, and NaBa, with a peritectic at 197 C. The assessed NaBa/[L + NaBa] solidus boundary was determined semiquantitatively. The solubility of Ba in (Na) reaches a maximum of 1.2 at.% at 70 C, and the maximum solubility of Na in (Ba) is 5 at.% at 197 C. Na was found to be very soluble in NaBa [65Kan]. Thermodynamic analysis was performed to obtain the thermodynamic properties of the liquid phase and of the (bNa) and (Ba) solid solutions. Phase boundaries of the [L + (Ba)] and [L + (bNa)] regions shown in the assessed diagram were calculated via this thermodynamic analysis. A peritectoid reaction involving (bNa), NaBa, and another compound was reported at 70 с 0.5 C by [71Add] and at 65 с 5 C by [65Kan]. The other compound associated with this reaction was identified by X-ray studies as Na4Ba by [65Kan]. No evidence of soubility of Ba in NaBa was found, but substantial solubility of Na in NaBa was reported. However, this was observed only after homogenization by soaking from 1 to 42 days. During conventional slow cooling at rates of 1 C/min, eutectic and peritectoid halts were observed at compositions up to 45 at.% Ba by [65Kan] and [71Add]. Visible segregation of samples was observed in the NaBa region [65Kan] due to settling of the much denser NaBa phase. 65Kan: F.A. Kanda, R.M. Stevens, and D.V. Keller, J. Phys. Chem., 69, 3867- 3872 (1965). 71Add: C.C. Addison, G.K. Creffield, P. Hubberstey, and R.J. Pulham, J. Chem. Soc. A, 16, 2688-2691 (1971). Published in Bull. Alloy Phase Diagrams, 6(1), Feb 1985. Complete evaluation contains 2 figures, 2 tables, and 10 references. 1