Фазовая диаграмма системы Bi-Te

К оглавлению: Другие диаграммы (Others phase diargams)

Bi-Te (Bismuth-Tellurium) H. Okamoto and L.E. Tanner Many versions of the Bi-Te equilibrium phase diagram have been proposed, and at least one intermetallic phase, Bi2Te3, is generally accepted. Although [ 05Mon], [25End], [30Kor], and [70Laf] reported Bi2Te3 as the only intermediate phase in the Bi-Te system, other work seems to have established that there are several additional phases in the composition range ~30 to ~60 at.% Te [45War, 58Abr, 64Sta, 65Gla, 68Bre, 69Liu, 69Str, 79Yam]. The boundaries of the additional phases are very uncertain. The assessed Bi-Te phase diagram is a compromise of many contradictory experimental results and is most tentative in the range of stacking variants. The disagreement may be due to the fact that all intermediate phases are composed of two types of unit stacks, one based on pure Bi and the other on Bi2Te3, which may form ordered states at any ratio. Out of an infinite number of possible sequences of ordered stacking, only a limited number of structures are observable experimentally. The solubility of Bi in (Te) is 0.005 at.%, according to the density and Hall effect measurements of [63Ver]. A narrow Bi2Te3 range is included in the assessed phase diagram. It is not surprising that on the Bi-rich side of Bi2Te3, only gradual changes were observed in various physical properties, because the existence of a series of stacking variants and the slow ordering process of these stackings lead to the appearance of a wide single phase. A narrow Bi2Te3 phase field of ~1 at.% or less was first reported by [58Abr] based on thermo emf and thermal data and by [57Sat] based on the measured number of charge carriers in a zone-refined solid. All stacking variants comprise two fundamental stacks, one based on two-layer pure Bi and the other on five-layer stoichiometric Bi2Te3 [70Ima]. Known stacking variants are shown as line compounds in the assessed diagram. Dashed lines show probable variants. Bi2Se3-type Bi2Te3 transforms into an In2Se3-type, high-pressure phase, Bi2Te3II, at pressures higher than 40 kbar and temperatures higher than 400 C [68Ata]. The pressure dependence of the melting point of Bi2Te3 was measured by [61Li], [62Bal], and [65Sti]. Their results are in good agreement. The melting point increases with increasing pressure up to a maximum of 603.3 C at 16 kbar [ 61Li]. Then the melting temperature decreases to 595 C at 25 kbar [65Sti] ( maximum pressure measured) and to 535 C at 50 kbar [62Bal]. 05Mon: K. Monkemeyer, Z. Anorg. Allg. Chem., 46(4), 415-422 (1905) in German. 25End: H. Endo, Sci. Rep. Tohoku Univ., 14, 479-512 (1925). 30Kor: F. Korber and U. Haschimoto, Z. Anorg. Allg. Chem., 188, 114-126 (1930) in German. 45War: H.V. Warren and M.A. Peacock, Univ. Toronto Stud., Geol. Ser., (49), 55- 69 (1945). 57Sat: C.B. Satterthwaite and R.W. Ure, Jr., Phys. Rev., 108(5), 1164-1170 ( 1957). 58Abr: N.Kh. Abrikosov and V.F. Bankina, Zh. Neorg. Khim., 3(3), 659-667 (1958) in Russian; TR: J. Inorg. Chem., 3(3), 152-165 (1958). 61Li: C.Y. Li, A.L. Ruoff, and C.W. Spencer, J. Appl. Phys., 32, 1733-1735 ( 1961). 62Bal: D.L. Ball, Inorg. Chem., 1(4), 805-811 (1962). 63Ver: V.I. Veraksa, V.N. Lange, and T.I. Lange, Zh. Fiz. Khim., 37(10), 2308- 2310 (1963) in Russian; TR: Russ. J. Phys. Chem., 37(10), 1245-1246 (1963). 64Sta: M.M. Stasova, Zh. Strukt. Khim., 5(5), 793-794 (1964) in Russian; TR: J. Struct. Chem. USSR, 5(5), 731-732 (1964). 65Gla: A.C. Glatz, J. Electrochem. Soc., 112(12), 1204-1207 (1965). 65Sti: S.M. Stishov and N.A. Tikhomirova, Zh. Eksp. Teor. Fiz., Pis'ma Red., 1( 1), 20-22 (1965) in Russian; TR: JETP Lett., 1(1), 12-13 (1965). 68Ata: E.Ya. Atabaeva, E.S. Itskevich, S.A. Mashkov, S.V. Popova, and L.F. Vereshchagin, Fiz. Tverd. Tela, 10(1), 62-65 (1968) in Russian; TR: Sov. Phys. Solid State, 10(1), 43-46 (1968). 68Bre: R.F. Brebrick, J. Appl. Crystallogr., 1(4), 241-246 (1968). 69Liu: C.C. Liu and J.C. Angus, J. Electrochem. Soc., 116(8), 1054-1060 (1969). 69Str: J. Strassburger, J. Electrochem. Soc., 116(5), 640-645 (1969). 70Ima: P.M. Imamov and S.A. Semiletov, Kristallografiya, 15(5), 972-978 (1970) in Russian; TR: Sov. Phys. Crystallogr., 15(5), 845-850 (1971). 70Laf: M. Laffitte, R. Castanet, and Y. Claire, High Temp.-High Pressures, 2(3) , 317-323 (1970) in French. 79Yam: K. Yamana, K. Kihara, and T. Matsumoto, Acta Crystallogr. B, 35(1), 147- 149 (1979). Submitted to the APD Program. Complete evaluation contains 4 figures, 11 tables, and 81 references. 1