Фазовая диаграмма системы Au-Hg

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Au-Hg (Gold-Mercury) H. Okamoto and T.B. Massalski The assessed Au-Hg phase diagram is based on the work of [67Rol], in which the following phases are included: (1) the liquid, L; (2) the fcc terminal solid solution, (Au), having about 19.8 at.% solubility of Hg in (Au); (3) the rhombohedral terminal solid solution, (Hg), having no reported solubility of Au in (Hg); (4) the a1 phase with a long-range ordered cph crystal structure, stable below 419 C and having about 1 at.% solubility range; (5) the cph z phase (Au3Hg), stable below 388 C and having about 5 at.% solubility range; and (6) the Au2Hg intermetallic compound with a hexagonal symmetry, having a homogeneity range of less than с1 at.%. It must be stressed that the assessed diagram represents a phase diagram determined under variable pressure. It is possible that the equilibrium diagram at constant pressure may be different in important details. Because of the low melting and boiling points of Hg (-38.836 C and 356.6 C, respectively), phase diagram-related experiments must be performed under sealed conditions to suppress the loss of Hg. Thus, pressure contributes as an unknown parameter. It is likely that many of the intermediate phases shown in the phase diagram are metastable under standard state conditions. No systematic research has been conducted on the relationship between the stability of the phases and pressure. In the assessed diagram, many potential phases are indicated by a line at the appropriate composition. 67Rol: C. Rolfe and W. Hume-Rothery, J. Less-Common Met., 13(1), 1-10 (1967). Published in Phase Diagrams of Binary Gold Alloys, 1987, and Bull. Alloy Phase Diagrams, 10(1), Feb 1989. Complete evaluation contains 5 figures, 4 tables, and 38 references. 1