Фазовая диаграмма системы Au-Co

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Au-Co (Gold-Cobalt) H. Okamoto, T.B. Massalski, M. Hasebe, and T. Nishizawa The equilibrium phases of the Au-Co system are (1) the liquid, L; (2) the fcc terminal solid solution, (Au), having a maximum solid solubility of 23.0 at.% of Co in (Au) at the eutectic temperature of 996.5 C; (3) the fcc terminal solid solution based on the high-temperature allotropic form, (aCo), having a maximum solid solubility of 2.5 at.% Au in (aCo) at about 1200 C; and (4) the cph terminal solid solution based on the low-temperature allotropic form, (eCo) , stable below 422 C, having a very limited (<0.05 at.%) solubility of Au in ( eCo). The assessed phase boundaries are based mainly on the results of thermodynamic calculations, which are in good agreement with the experimental data of [50Rau] and [84Tas]. The L/[L + (aCo)] liquidus boundary is based on the results of [84Tas]. A metastable fcc phase was found [63Kle] over a wide composition range in splat-cooled alloys. An amorphous phase also forms when the quenching rate is sufficiently high, as observed first by [66Fuj]. [83Liu] also found a cph metastable phase in alloys with 82 and 87 at.% Co, which is less stable than the fcc phase. 50Rau: E. Raub and P. Walter, Z. Metallkd., 41(8), 234-238 (1950) in German. 63Kle: W. Klement, Jr., Trans. AIME, 227(8), 965-970 (1963). 66Fuj: S. Fujime, Jpn. J. Appl. Phys., 5(8), 739-740 (1966). 83Liu: B.X. Liu and M.A. Nicolet, Thin Solid Films, 101(3), 201-206 (1983). 84Tas: P. Taskinen, Scand. J. Met., 13(1), 39-45 (1984). Published in Phase Diagrams of Binary Gold Alloys, 1987, and Bull. Alloy Phase Diagrams, 6(5), Oct 1985. Complete evaluation contains 5 figures, 6 tables, and 28 references. Special Points of the Au-Co System