Фазовая диаграмма системы Cu-Hg

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Cu-Hg (Copper-Mercury) D.J. Chakrabarti and D.E. Laughlin The equilibrium phases of the Cu-Hg system are (1) the liquid, L, with a region of immiscibility below ~810 C, which extends down to 660 C and from 15 to ~90 at.% Hg; (2) the fcc solid solution, (Cu), which extends up to 5 at.% Hg at 660 C; (3) the rhombohedral solid solution, (Hg), which is stable below approximately -38.8 C and has negligible solubility of Cu; and (4) the rhombohedral intermediate phase, g, presumably of stoichiometry Cu7Hg6, which forms peritectically at 128 C. The lower temperature limit of stability of g is not known. The assessed Cu-Hg phase diagram is based primarily on the work of [71Lug] and [63Jan]. It is characterized by the presence of a wide region of immiscibility in the liquid and a nearly vertical liquidus at the Hg-rich end. The invariant temperature at which the liquidus terminates has not been determined; consequently, it is not known whether this involves a eutectic or a peritectic transformation. A miscibility gap extends from 15 to about 90 at.% Hg at the monotectic temperature of 660 C. The critical point occurs at about 810 C and between 50 and 55 at.% Hg. The solid solubility of Hg in (Cu) is presumably negligible at room temperature; it increases to a maximum of 5 at.% at 660 C and remains nearly constant at that value up to ~750 C. The solubility of Cu in (Hg) at room temperature is accepted to be 0.006 at.%, based on [32Irv] and [63Jan]. No metastable phases have been reported in the Cu-Hg system, but indirect evidence [32Irv] suggests the likelihood of one or more metastable intermediate phases being present. 32Irv: N.M. Irvin and A.S. Russell, J. Chem. Soc., 891-898 (1932). 63Jan: G. Jangg and H. Palman, Z. Metallkd., 54, 364-369 (1963) in German. 71Lug: E. Lugscheider and G. Jangg, Z. Metallkd., 62, 548-551 (1971) in German. Published in Bull. Alloy Phase Diagrams, 6(6), Dec 1985. Complete evaluation contains 2 figures, 4 tables, and 29 references. 1