Фазовая диаграмма системы As-Cd

К оглавлению: Другие диаграммы (Others phase diargams)

As-Cd (Arsenic-Cadmium) H. Okamoto The assessed As-Cd phase diagram is based primarily on [70Guk] for 0 to 33.3 at.% Cd and on [13Zem] for 33.3 to 100 at.% Cd. Because of the high volatility of As, the pressure on the As-rich side of the assessed diagram is not 1 atm. The equilibrium diagram at 1 atm pressure should involve the gas As phase. The assessed solid-phase transition temperatures are rounded averages of the reported values. The equilibrium phases of the assessed diagram are (1) the liquid L; (2) the rhombohedral terminal solid solution (As); (3) As2Cd, possibly with a few allotropic modifications; (4) b-, a››-, a›-, and aAs2Cd3; and (5) the hexagonal terminal solid solution (Cd). As sublimes at 614 C under 1 atm pressure [Melt]. The As vapor is >1 atm at the melting point of As2Cd [60Lyo]. Therefore, the entire (As) liquidus in the assessed diagram occurs at pressures higher than 1 atm. As2Cd exists in at least two crystalline forms (a and g) [70Uga2] and in an amorphous form (b) [68Uga, 70Uga1]. However, the stability ranges were not reported. Because only one crystal structure of As2Cd is known, no phase transition is shown in the assessed diagram. Amorphous As2Cd is formed by slow cooling from 700 to 500 C, followed by cooling to room temperature at the rate of 30 C/s [68Uga]. bAs2Cd crystallizes at 400 to 415 C on rapid heating [68Uga]. Amorphous As2Cd3 has been formed by vapor deposition on a substrate kept at 20 to 100 C [70Zda] or below 130 C [75Zda]. [65Uga] observed As4Cd3. No similar phase was reported by other investigators. No report is available on the solubility of As in (Cd). The formation of As2Cd on cooling can be easily suppressed, unless the melt is inoculated [13Zem] or continuously vibrated [70Guk]. The L/[L + (As)] liquidus temperature is also lowered by as much as ~50 C [70Guk]. This supercooling temperature must be related to the cooling rate of the specimen and the pressure condition. Therefore, the following observations may include substantial uncertainties. [77Pru] indicated two possibilities in the metastable diagram in the vicinity of As2Cd. If metastable As4Cd is formed peritectically from L and (As) at 580 C, the metastable L = As4Cd + As2Cd3 eutectic point is located at ~36 at.% Cd and 548 C. If As4Cd is not formed, the L = (As) + As2Cd3 metastable eutectic is observed at ~33 at.% Cd and 508 C. This metastable eutectic was observed at ~38 at.% Cd and 526 C by [13Zem] or 530 C by [70Guk]. The melting point of As2Cd decreases from 621 C at ambient pressure to 579.5 C at 19.8 kbar. The maximum melting point of As2Cd is 627.4 C, occurring at 60 kPa (~0.6 atm) [85Nip]. A high-pressure phase As2PdII exists above this pressure [73Cla]. As2CdII may have two polymorphic forms [75Cla]. [75Cla] found that AsCd forms as a decomposition product of As2Cd at high pressure and temperature and also by a reaction As2Cd3 + As <259> 3AsCd at 40 kbar and 850 to 1000 C. According to DTA measurements on As2Cd3 under pressures up to 40 kbar, the melting point decreases linearly from 697 C (lower than the assessed value) at zero pressure to 645 с 5 C at 17 kbar, above which existence of a high- pressure phase with La2O3-type structure was speculated [66Jay]. More recent DTA and volumetric studies of [75Pis] up to 40 kbar revealed four high- pressure phases; the crystal symmetry of the high-pressure phase at low temperatures is orthorhombic. The existence of high-pressure, high-temperature phases (II› and III›) must be corroborated, because the thermal effects at the proposed phase boundaries may not be due to a phase transition [75Pis]. The melting point of As2Cd3 reaches a maximum of 715 C at 20 kPa (~1/5 atm) [ 85Nip]. 13Zem: S.F. Zemczuzny, Int. Z. Metallogr., 4, 228-247 (1913). 28Pas: L. Passerini, Gazz. Chim. Ital., 58, 775-781 (1928) in Italian. 35Sta: M.V. Stackelberg and R. Paulus, Z. Phys. Chem. B, 28(6), 427-460 (1935) in German. 60Lyo: V.J. Lyons and V.J. Silvestri, J. Phys. Chem., 64(2), 266-269 (1960). 60Ste: N.R. Stemple and M.E. Senko, Pittsburgh Diffusion Conf. Abs., p 20 ( 1960). 64Zda: W. Zdanowicz, K. Lukaszewicz, and W. Trzebiatowski, Bull. Acad. Pol. Sci., Ser. Sci. Chim., 12, 169-176 (1964). 65Cas: G.A. Castellion and L.C. Beegle, J. Phys. Chem. Solids, 26, 766-773 ( 1965). 65Uga: Ya.A. Ugai and T.A. Zyubina, Izv. Acad. Nauk SSSR, Neorg. Mater., 1, 860-867 (1965) in Russian; TR: Inorg. Mater., USSR, 1, 790-796 (1965). 66Jay: A. Jayaraman, T.R. Anantharaman, and W. Klement, Jr., J. Phys. Chem. Solids, 27(10), 1605-1609 (1966). 66Kol: B. Koltirine and M. Chaumereuil, Phys. Status Solidi, 13, K1-K3 (1966) in French. 67Zda: W. Zdanowicz, Physical Chemistry of Solids, Ewa. Paust. Wydawnictwo Nauk, Warsaw, 75-122 (1967) in Polish. 68Ale: K.B. Aleinikova, T.A. Zyubina, N.A. Ignatev, and Ya.A. Ugai, Tr. Plouplov Mater., Prib. Ikh. Primen, Voronezh., 49-51 (1968) in Russian. 68Hor: J. Horn and K. Lukaszewicz, Roczn. Chem., 42, 993-999 (1968) in Polish. 68Kat: H. Katzman, T. Donohue, and W.F. Libby, Phys. Rev. Lett., 20(9), 442 ( 1968). 68Ste: G.A. Steigmann and J. Goodyear, Acta Crystallogr. B, 24, 1062-1067 ( 1968). 68Uga: Ya.A. Ugai, T.A. Zyubina, and K.B. Aleinikova, Izv. Acad. Nauk SSSR, Neorg. Mater., 4(1), 17-21 (1968) in Russian; TR: Inorg. Mater., USSR, 4(1), 12-15 (1968). 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). 69Pie: A. Pietraszko and K. Lukaszewicz, Acta Crystallogr. B, 25(5), 988-990 ( 1969). 70Bok: G.B. Bokii, G.I. Goncharenko, G.G. Dvoryankina, V.I. Kovalev, and V.Ya. Shevchenko, Dokl. Acad. Nauk, SSSR, 195(3), 603-606 (1970) in Russian. 70Cer: L. Cervinka and A. Hruby, Acta Crystallogr. B, 26(4), 457-458 (1970). 70Guk: O.Ya. Gukov, Ya.A. Ugai, V.R. Pshestanchik, E.G. Gonchrov, and N.V. Pakhomova, Izv. Acad. Nauk SSSR, Neorg. Mater., 6(11), 1926-1929 (1970) in Russian; TR: Inorg. Mater., USSR, 6(11), 1693-1695 (1970). 70Uga1: Ya.A. Ugai, T.A. Zyubina, and K.B. Aleinikova, Izv. Acad. Nauk SSSR, Neorg. Mater., 6(2), 266-270 (1970) in Russian; TR: Inorg. Mater., USSR, 6(2), 231-233 (1970). 70Uga2: Ya.A. Ugai et. al., Process of Growth of Semiconductor Crystals and Films, Novosibirsk, 330 p (1970); quoted in [79Vol]. 70Zda: L. Zdanowicz and W. Zdanowicz, Exp. Tech. Phys., 18(3), 185-197 (1970). 72Ole: I.D. Oleksyuk, M.I. Golovei, M.Yu. Rigan, Yu.V. Voroshilov, and M.I. Gurzan, Izv. Acad. Nauk SSSR, Neorg. Mater., 8(4), 696-700 (1972) in Russian; TR: Inorg. Mater. USSR, 8(4), 607-610 (1972). 73Cla: J.B. Clark and C.W.F.T. Pistorius, High Temp. -High Press., 5(3), 319- 326 (1973). 73Gol: M.I. Golovei, M.Yu. Rigan, I.D. Olekseyuk, and Yu.V. Voroshilov, Izv. Acad. Nauk SSSR, Neorg. Mater., 9(9), 1520-1523 (1973) in Russian; TR: Inorg. Mater., USSR, 9(9), 1354-1356 (1973). 73Pie: A. Pietraszko and K. Lukaszewicz, Phys. Status Solidi (a), 18(2), 723- 730 (1973). 75Cla: J.B. Clark and K.J. Range, Z. Naturforsch. B, 30(5), 688-695 (1975). 75Pal: K.K. Palkina, V.G. Kuznetsov, V.B. Lazarev, S.F. Marenkin, V.Ya. Shevchenko, and L.G. Maruga, Zh. Neorg. Khim., 20(8), 2026-2028 (1975) in Russian; TR: Russ. J. Inorg. Chem., 20(8), 1129-1130 (1975). 75Pis: C.W.F.T. Pistorius, High Temp.-High Press., 7(4), 441-449 (1975). 75Zda: L. Zdanowicz and S. Miotkowska, Thin Solid Films, 29(1), 171-183 (1975). 76Cla: J.B. Clark and K.J. Range, Z. Naturforsch. B, 31(2), 158-162 (1976). 77Pru: Z. Pruchnik, Mater. Sci., 3(4), 121-125 (1977). 78Mar: S.F. Marenkin, S.I. Maksimova, B. Khuseinov, and V.Ya. Shevchenko, Izv. Acad. Nauk SSSR, Neorg. Mater., 14(3), 397-400 (1978) in Russian; TR: Inorg. Mater., USSR, 14(3), 295-298 (1970). 79Vol: A.E. Vol and I.K. Kagan, Handbook of Binary Metallic Systems, Nauka Pub. , Moscow (1979). 85Nip: G.D. Nipan, H.J. Greenberg, and V.B. Lazarev, Mater., Res. Bull., 20(9), 1115-1122 (1985). Submitted to the APD Program. Complete evaluation contains 3 figures, 3 tables, and 63 references. Special Points of the As-Cd System