Фазовая диаграмма системы Au-Na

К оглавлению: Другие диаграммы (Others phase diargams)

Au-Na (Gold-Sodium) A.D. Pelton The assessed Au-Na phase diagram is based primarily on the work of [11Mat] and [61Kie]. The existence of the compounds Au2Na, AuNa, and AuNa2 is well established. Au2Na has a wide range of homogeneity. The existence of the compound Au5Na at 775 C has recently been reported [84Ega]. AuNa2 melts congruently at 1002 с 10 C, whereas AuNa and AuNa2 melt peritectically at 372 с 5 and 163 с 5 C, respectively. The liquidus in the Au-rich regions was determined by thermal analysis by [ 11Mat]. Error limits of с25 to с50 C apply to most of the liquidus in the present diagram. The smoothed liquidus was calculated from a thermodynamic analysis. Thermodynamic calculations using the enthalpy of melting of pure Na from [ 83Cha], assuming limiting Raoult's law behavior, yield a eutectic composition of 96.1 at.% Na at 81 C for the lower eutectic. Peritectics were observed at 372 and 163 C by [61Kie] using thermal analysis. The solubility of Au in (Na), which is very slight, has been measured in the range of 31 to 51 C [69Bar]. No measurements of the solubility of Na in (Au) are available. 11Mat: C.H. Mathewson, Int. Z. Metall., 1, 81-88 (1911). 61Kie: G. Kienast and J. Verma, Z. Anorg. Allg. Chem., 310, 143-169 (1961) in German. 69Bar: L.W. Barr, J.N. Mundy, and F.A. Smith, Philos. Mag., 20, 389-398 (1969). 83Cha: M.W. Chase, Bull. Alloy Phase Diagrams, 4, 124 (1983). 84Ega: J. Egan and R. Algasmi, Brookhaven National Lab., private communication (1984). Published in Phase Diagrams of Binary Gold Alloys, 1987, and Bull. Alloy Phase Diagrams, 7(2), Apr 1986. Complete evaluation contains 1 figure, 1 table, and 20 references. 1