Фазовая диаграмма системы Fe-Te

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Fe-Te (Iron-Tellurium) H. Okamoto and L.E. Tanner The phases in the assessed Fe-Te equilibrium diagram are (1) the liquid, L; (2) the W-type bcc terminal solid solution, (aFe); (3) the Cu-type fcc terminal solid solution, (gFe); (4) rhombohedral, high-temperature b›; (5) PbO- or Cu2Sb-type tetragonal b; (6) g, with an unknown crystal structure; (7) Cr3Se4- type monoclinic d; (8) NiAs-type hexagonal d›, very similar to d; (9) FeSb2- type orthorhombic e; and (10) the gSe-type (Te) terminal solid solution. b transforms into a monoclinic form, b1, below -210 C (63 K). e transforms to a cubic FeS2-type phase, FeTe2I, under high pressures. Most of the important features in the assessed diagram are based primarily on thermal and isopiestic experimental data [74Ips]. In the original diagram of [59Lle] (modified by [Elliott] to avoid some ambiguity), there is a z phase, which appears to be a high-temperature modification of e with either NiAs - or CdI2-type hexagonal structure. [70Abr] reported two high-temperature phases-z (750 to 825 C) and h (722 to 772 C)- at around 50 at.% Te. [74Ips] could not corroborate these findings. A large amount of information is available on the magnetic properties of Fe-Te alloys. The difference in alloy compositions, degree of order, presence of a second phase, and other factors appear to cause conflicting results. Typical examples related to the phase diagram follow. According to [55Chi], the N‚el temperature of b is -143 C. [59Wes] found a sharp maximum in the specific heat of a 47.4 at.% Te alloy at -210 C, which is in agreement with the transition temperature of b to b1 observed by [75Fru]. [60Nay] found well-defined anomalies in electrical conductivity and in magnetic susceptibility at 260 and 206 C, respectively, in a 48.7 at.% Te alloy. According to [76Red], the M”ssbauer quadrupole spectrum of an alloy of the same composition collapses at 147 C. The N‚el temperatures of d› and e are 527 and -206 C, respectively [55Chi]. 55Chi: S. Chiba, J. Phys. Soc. Jpn., 10(10), 837-842 (1955). 59Lle: J.P. Llewellyn and T. Smith, Proc. Phys. Soc. (London), 74(1), 65-74 ( 1959). 59Wes: E.F. Westrum, Jr., C. Chou, and F. Gronvold, J. Chem. Phys., 30(3), 761- 764 (1959). 60Nay: R. Naya, M. Murakami, and E. Hirahara, J. Phys. Soc. Jpn., 15, 360-361 ( 1960). 70Abr: N. Kh. Abrikosov, K.A. Dyul'dina, and V.V. Zhdanova, Khal'kogenidy, (2), 98-114 (1970) in Russian. 74Ips: H. Ipser, K.L. Komarek, and H. Mikler, Monatsh. Chem., 105(6), 1322- 1334 (1974). 75Fru: D. Fruchart, P. Convert, P. Wolfers, R. Madar, J.P. Senateur, and R. Fruchart, Mater. Res. Bull., 10(3), 169-174 (1975) in French. 76Red: K.V. Reddy and S.C. Chetty, Phys. Status Solidi (a), 37(2), 687-694 ( 1976). Published in Bull. Alloy Phase Diagrams, 11(4), Aug 1990. Complete evaluation contains 1 figure, 3 tables, and 37 references. Special Points of the Fe-Te System