Фазовая диаграмма системы Au-In

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Au-In (Gold-Indium) H. Okamoto and T.B. Massalski The equilibrium phases of the Au-In system are (1) the liquid, L; (2) the fcc terminal solid solution, (Au), with about 12.5 at.% solubility of In; (3) the bct terminal solid solution, (In), with no recognizable solid solubility; (4) the aLa-type (or Ni3Ti-type) hexagonal a1 phase, Au7In; (5) the cph z phase, with solubility ranging from 13 to 23 at.% In; (6) the b phase, which is reported to be either orthorhombic or hexagonal; (7) the cph b1 phase, which is stable at a lower temperature range than the b phase; (8) the bCu3Ti-type e› phase, Au3In; (9) the e phase, which is a disordered phase of e› (10) the hexagonal g› phase, Au7In3; (11) the g brass type g phase, stable between 28.8 and 31.4 at.% In, with an approximate atomic composition of Au9In4; (12) the Ni2Al3-type y phase, stable between 35.3 and 39.5 at.% In, with an approximate atomic composition of Au3In2; (13) the triclinic intermetallic compound AuIn, with 50 to 50.1 at.% In solubility range; and (14) the fluorite (CaF2)-type intermetallic compound AuIn2, with no appreciable solubility range. The assessed phase diagram is based primarily on the work of [64His], with review of the studies of [38Kub], [45Owe], [71Nik], and [72Str]. The calculated phase diagram exhibits reasonable agreement with the experimental data. The temperature dependence of the heat of mixing and heat capacity measurements indicates the existence of Au-In associations in the liquid phase, most notable at about 55 at.% In. Associations decrease with increasing temperature [81Cas]. The accepted [L + (Au)]/(Au) solidus boundary shows a retrograde solubility, with the maximum solubility of ~12.7 at.% In in (Au) at 680 C, which is only 0.2 at.% more than the solubility of In at the peritectic point. No evidence of solid solubility of Au in (In) has been detected. The melting point of AuIn2 remains almost constant under pressure up to 3 GPa and then increases with pressure at the rate of 11.5 C/GPa. This indicates a possible polymorphic transition at 3 GPa [66Sto]. Editor's note: A thermodynamic model consistent with the phase diagram and thermodynamic data was reported by [88Ans]. 38Kub: O. Kubaschewski and F. Weibke, Z. Elektrochem., 44, 870-877 (1938) in German. 45Owe: E.A. Owen and E.A.O. Roberts, J. Inst. Met., 71, 213-254 (1945). 64His: S.E.R. Hiscocks and W. Hume-Rothery, Proc. R. Soc. (London), A282, 318- 330 (1964). 66Sto: A.R. Storm, J.H. Wernick, and A. Jataraman, J. Phys. Chem. Solids, 27, 1227-1232 (1966). 71Nik: V.K. Nikitina, A.A. Babitsyna, and Yu.K. Lobanova, Izv. Akad. Nauk SSSR, Neorg. Mater., 7(3), 421-427 (1971) in Russian ; TR: Inorg. Mater., 7(3), 371- 376 (1971). 72Str: M.E. Straumania and V.K. Patel, Z. Metallkd., 63(1), 33-37 (1972). 81Cas: R. Castanet, W. Ditz, K.L. Komarek, and E. Reiffenstein, Z. Metallkd., 72(3), 176-180 (1981). 88Ans: I. Ansara and J.P. Nabot, Thermochim. Acta, 129, 89-97 (1988). Published in Phase Diagrams of Binary Gold Alloys, 1987. Complete evaluation contains 6 figures, 8 tables, and 45 references. Special Points of the Au-In System