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