Фазовая диаграмма системы Au-Sr

К оглавлению: Другие диаграммы (Others phase diargams)

Au-Sr (Gold-Strontium) C.B. Alcock, V.P. Itkin, H. Okamoto, and T.B. Massalski The equilibrium phases of the Au-Sr system are (1) the liquid, L; (2) the terminal fcc solid solution, (Au), with very small solid solubility of Sr; (3) the terminal bcc solid solution, (bSr), with unknown solubility of Au; (4) the terminal fcc solid solution, (aSr), which is stable below 547 C and has very small solubility of Au; and (5) several intermetallic phases (Au5Sr, Au2Sr, AuSr3, and AuSr9) and phases denoted as a, b, and g. The assessed phase diagram is based on the work of [60Fel], with some modifications. According to [60Fel], the liquidus line from the melting point of Au goes down to the eutectic point (890 C at 7 at.% Sr) almost as a straight line at a rate of about -25 C/at.%. However, according to thermodynamic calculations in the present evaluation, the initial slope of the liquidus for an ideal solution is -11.7 C/at.%. The significant difference between the measured and estimated values indicates that the shape of the liquidus line between Au and the eutectic point indicated by [60Fel] is most probably wrong. Therefore, this portion of the diagram is shown as a dashed line. 60Fel: M. Feller-Kniepmeier and T. Heumann, Z. Metallkd., 51, 404-408 (1960) in German. Published in Phase Diagrams of Binary Gold Alloys, 1987, and Bull. Alloy Phase Diagrams, 7(5), Oct 1986. Complete evaluation contains 1 figure, 1 table, and 7 references. Special Points of the Au-Sr System