Фазовая диаграмма системы As-Zn

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As-Zn (Arsenic-Zinc) H. Okamoto The assessed As-Zn phase diagram is based primarily on [21Hei] for the As-rich liquidus and invariant reactions, on [79Laz] for the homogeneity range of As2Zn, and on [81Laz] for the liquidus near As2Zn3, with review of the data of [06Fri]. The equilibrium diagram at 1 atm pressure should involve the gaseous As phase. The equilibrium phases are (1) the liquid, L; (2) the rhombohedral terminal solid solution, (As); (3) monoclinic As2Zn; (4) b-, a›-, and aAs2Zn3-, and (5) the hexagonal terminal solid solution, (Zn). It must be noted that the phase boundaries on the As-rich side were measured under unspecified pressures higher than 1 atm. The L = (As) + As2Zn eutectic point is at 21 at.% Zn and 723 C [21Hei]. As2Zn dissociates incongruently into As2Zn3 and As4 gas. The dissociation pressure is log (P mmHg) = -12 300/T + 15.0 [59Lyo]. The L = As2Zn + As2Zn3 eutectic point is 41 at.% Zn and 750 C [21Hei]. The b to a› transition temperature was reported variously by different investigators The result of [75Pis], 651 C, is shown in the assessed diagram. The homogeneity range of As2Zn3 is narrow [21Hei]. More precisely, the solubility of As in bAs2Zn3 is at least 0.002 at.% at 672 C [81Laz]. The solubility of As in aAs2Zn3 does not exceed 5 x 10-4 at.% [81Laz]. The L = As2Zn3 + (Zn) eutectic temperature and the melting point of Zn are essentially the same [06Fri, 21Hei]. AsZn2 reported by [04Kon] may be As2Zn3. The lattice parameter vs composition diagrams of the As2Cd3-As2Zn3 system given by [64Zda1], [64Zda2], and [65Cas] indicated existence of a modification of As2Zn3 with the same crystal structure as a››As2Cd3. The existence of this Zn3P2-type phase was reported earlier by [35Sta]. However, the relation to other polymorphic forms has not been reported. In a review on the effect of pressure on the As-Zn phase diagram [87Cla], the change in the liquidus surface at up to 4 GPa is illustrated. [73Cla] and [75Cla] determined the pressure-temperature diagram of As2Zn up to 42 kbar. The melting point of As2Zn decreased from 723 C at ambient pressure to 679 C at 19.0 kbar. [75Cla] found that AsZn forms as a decomposition product of As2Zn at high pressure and temperature and also by a reaction As2Zn3 + As <259> 3AsZn at 40 kbar and 800 to 1200 C. The orthorhombic structure was determined by [76Cla]. The pressure-temperature diagram of As2Zn3 under pressures up to 40 kbar was first determined by [66Jay]. A similar but more detailed diagram for the same pressure range was published by [75Pis]. 04Kon: G.A. Konig, Z. Kristallogr., 38, 543 (1904), as quoted in [Hansen]. 06Fri: K. Friedrich and A. Leroux, Metallurgie, 3(14), 477-479 (1906) in German. 21Hei: W. Heike, Z. Anorg. Allg. Chem., 118(3), 264-268 (1921) in German. 28Nat: G. Natta and L. Passerini, Gazz. Chim. Ital., 58, 545-550 (1928) in Italian. 33Sta: M. v. Stackelberg and R. Paulus, Z. Phys. Chem. B, 22, 305-322 (1933) in German. 35Sta: M. v. Stackelberg and R. Paulus, Z. Phys. Chem. B, 28(6), 427-460 (1935) in German. 56Col: H. Cole, F.W. Chambers, and H.M. Dunn, Acta Crystallogr., 9, 685 (1956). 59Lyo: V.J. Lyons, J. Phys. Chem., 63(7), 1142-1144 (1959). 59Sen: M.E. Senko, H.M. Dunn, J. Weidenborner, and H. Cole, Acta Crystallogr., 12, 76 (1959). 64Naa: H.J. Naake and C.S. Belcher, J. Appl. Phys., 35, 3064-3065 (1964). 64Zda1: W. Zdanowicz, K. Lukaszewicz, and W. Trzebiatowski, Bull. Acad. Pol. Sci., Ser. Sci. Chim., 12, 169-176 (1964). 64Zda2: L. Zdanowicz and W. Zdanowicz, Phys. Status Solidi, 6, 227-234 (1964). 65Cas: G.A. Castellion and L.C. Beegle, J. Phys. Chem. Solids, 26, 766-773 ( 1965). 66Jay: A. Jayaraman, T.R. Anantharaman, and W. Klement, Jr., J. Phys. Chem. Solids, 27, 1606-1609 (1966). 68Weg: S. Weglowski and K. Lukaszewicz, Bull. Acad. Pol. Sci., Ser. Sci. Chim., 16(4), 177-182 (1968). 69Ban: M.D. Banus and M.C. Lavine, High Temp.-High Press., 1(3), 269-276 (1969) . 73Cla: J.B. Clark and C.W.F.T. Pistorius, High Temp.-High Press., 5(3), 319- 326 (1973). 73Pie: A. Pietraszko and K. Lukaszewicz, Phys. Status Solidi (a), 18(2), 723- 730 (1973). 74Fle: M.E. Fleet, Acta Crystallogr. B, 30, 122-126 (1974). 75Cla: J.B. Clark and K.J. Range, Z. Naturforsch. B, 30(5), 688-695 (1976). 75Pis: C.W.F.T. Pistorius, High Temp.-High Press., 7(4), 441-449 (1975). 76Cla: J.B. Clark and K.J. Range, Z. Naturforsch. B, 31(2), 158-162 (1976). 76Pie: A. Pietraszko and K. Lukaszewicz, Bull. Acad. Pol. Sci., Ser. Sci. Chim. , 24(6), 459-464 (1976). 79Laz: V.B. Lazarev, S.F. Marenkin, S.I. Maksimova, B. Khuseinov, and V.Ya. Shevchenko, Izv. Akad. Nauk SSSR, Neorg. Mater., 15(5), 749-751 (1979) in Russian; TR: Inorg. Mater. USSR, 15(5), 586-587 (1979). 81Laz: V.B. Lazarev, V.N. Guskov, and J.H. Greenberg, Mater. Res. Bull., 16(9), 1113-1120 (1981). 87Cla: J.B. Clark, M.E. Thomas, and P.W. Richter, J. Less-Common Met., 132(2), 181-194 (1987). Submitted to the APD Program. Complete evaluation contains 3 figures, 4 tables, and 40 references. Special Points of the As-Zn System