Фазовая диаграмма системы Ag-C

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Ag-C (Silver-Carbon) I. Karakaya and W.T. Thompson The assessed Ag-C phase diagram is based primarily on review of experimental solubility studies [19Ruf, 69Mcl]. This system exhibits immiscibility to a very high degree. The solubility of Ag in graphite is extremely low, but not known precisely. The solid solubility of graphite in (Ag) was studied by a vapor transport technique [69Mcl] in the range 785 to 957 C. The solubility of graphite in fcc (Ag) at its melting point was found to be 0.036 at.%. Graphite has a much lower solubility in liquid Ag. At 1660, 1735, and 1940 C (boiling point), [ 19Ruf] reported 0.011, 0.022, and 0.20 at.%, respectively. One implication of the assessed diagram is that the apparent melting point of Ag in contact with graphite (actually, the peritectic) is higher than that for pure Ag. A yellow precipitate of Ag2C2 from an aqueous solution has been reported [ 49Ves, 59Sne]. The procedure involves the passing of acetylene into an ammoniacal solution of silver nitrate. When dry, the precipitate is white, photosensitive, and highly explosive [59Sne]. Other compounds of Ag and C have been reported, such as Ag4C and AgC [59Sne]. Their identity as true compounds is in doubt. 19Ruf: O. Ruff and B. Bergdahl, Z. Anorg. Allg. Chem., 106, 76-94 (1919) in German. 49Ves: R. Vestin and E. Ralf, Acta Chem. Scand., 3, 101-124 (1949). 59Sne: M.C. Sneed, J.L. Maynard, and R.C. Brasted, Comprehensive Inorganic Chemistry, Vol. II, D. Van Nostrand Co., Inc., New York (1959). 69Mcl: R.B. McLellan, Scr. Metall., 3, 389-391 (1969). Published in Bull. Alloy Phase Diagrams, 9(3), Jun 1988. Complete evaluation contains 1 figure, 1 table, and 5 references. 1