Фазовая диаграмма системы Ga-Sn

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Ga-Sn (Gallium-Tin) T.J. Anderson and I. Ansara The assessed Ga-Sn phase diagram is a simple eutectic, with a eutectic temperature of 20.5 C. The equilibrium phases are (1) the liquid, L; (2) the tetragonal (Sn) solid solution; and (3) the complex cubic solid solution, (aGa) . The assessed phase diagram is based on an optimization of the liquidus, solidus, and liquid phase thermodynamic data of [32Kro], [32Pus], [61Bos], [ 63Del], [64Pre], [74Shu1], [74Shu2], and [85Tre]. The Sn-rich liquidus data of [63Del] and [32Pus] show somewhat higher temperature values than the other measurements. The assessed liquidus lies between these data sets. Accurate determination of the liquidus temperature near 25 at.% Sn would be helpful in a future assessment. The solubility of Sn in (aGa) is quite small. [62Aud] determined the Ga-rich solidus by measuring the electrical resistance of (aGa) single crystals with three different Sn doping levels. The extrapolated solubility at the eutectic temperature is 0.016 at.% Sn. These measurements are compared to the electrical resistance studies of [61Bos], who reported a maximum solubility of 0.027 at.% Sn at the eutectic temperature. The assessed value of the maximum solubility (0.02 at.% Sn) is taken as the average of these two measurements. The maximum solubility of Ga in (Sn) reported by [64Pre] is 92.9 at.% Sn. The assessed value of the eutectic point solubility (93.6 at.% Sn) was determined from an optimization of select liquidus, solidus, and thermodynamic data. It appears possible to extrapolate the X-ray data of [64Pre] to agree with the assessed maximum solubility. When the solidus data of [64Pre] were not included in the optimization data base, the phase diagram changed negligibly, and the value of the Ga solubility in (Sn) at the eutectic temperature shifted to 93.9 at.% Sn. Ga crystallizes in a complex orthorhombic structure (bGa) on slow cooling or at elevated pressure. The Sn-rich liquidus was extended below the eutectic temperature by [63Del] by electrical resistance measurements. [63Del] also determined the Ga-rich liquidus of the (bGa)-Sn phase diagram using thermal methods at atmospheric pressure. A simple metastable eutectic phase diagram was constructed with a eutectic temperature of --23.36 C and composition of 3. 2 at.% Sn. The calculated eutectic composition and temperature differ very little from the assessed experimental values. 32Kro: W. Kroll, Metallwirtschaften, 2, 435-437 (1932) in German. 32Pus: N.A. Puschin, S. Stepanovic, and V. Stajic, Z. Anorg. Chem., 209, 329- 334 (1932) in German. 61Bos: L. Bosio, A. Defrain, M. Erny, S. Lignel, and I. Epelboin, M‚m. ђtud. Sci. Rev. Metall., 58, 43-51 (1961) in French. 62Aud: Ph. Audit, I. Epelboin, and M. Erny, M‚m. ђtud. Sci. Rev. Metall., 59, 233-239 (1962) in French. 63Del: S. Delcroix, A. Defrain, and I. Epelboin, J. Phys. Radium, 24, 17-20 ( 1963) in French. 64Pre: B. Predel, J. Less-Common Met., 7, 347-355 (1964) in German. 74Shu1: P.E. Shurai, V.N. Danilin, A.G. Dolesov, and I.T. Sryvalin, Trans. Krasnodar Politekh. Inst., 63, 128-131 (1974) in Russian. 74Shu2: P.E. Shurai, V.N. Danilin, and I.T. Sryvalin, Zh. Fiz. Khim., 48, 1325 (1974) in Russian; TR: Russ. J. Phys. Chem., 48, 780 (1974). 85Tre: A.A. Trebukhov, R.G. Sarmurzina, and D.V. Sokol'skii, Zh. Fiz. Khim., 59(8), 2065-2067 (1985) in Russian. Submitted to the APD Program. Complete evaluation contains 3 figures, 8 tables, and 31 references. Special Points of the Ga-Sn System