Фазовая диаграмма системы In-Nb

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In-Nb (Indium-Niobium) H. Okamoto The assessed In-Nb phase diagram is based on the diagram of [82Vil], which was determined by X-ray, metallography, and differential thermal analysis measurements with a heating rate of ~4 C/min and on [74Die] for the solubility of Nb in liquid In. Two intermediate phases exist: Cr3Si-type InNb3 and high-temperature e, stable above ~390 C. Because of contradictory experimental observations re-garding the solid phases and the possible existence of liquid immiscibility, the assessed diagram appears to be subject to further investigation. [69Das] predicted that the In-Nb liquid shows immiscibility. However, [82Vil] postulated that the liquidus is monotonic. The data of [74Die] are in agreement with [69Das]. The L = (In) + InNb3 eutectic temperature is 142 с 4 C [82Vil], which is definitely lower than the melting point of pure In (156.634 C [Melt]). According to the initial slope calculation of the (In) liquidus, the eutectic composition is about 3 at.% Nb, where the heat of fusion of In is 3280 J/mol [83Cha]. However, because the solubility of Nb in liquid In presumably is small, as indicated by possible liquid immiscibility [69Das], the calculated eutectic composition appears to be rather large. To be consistent, the eutectic temperature may need to be closer to the melting point of In than the reported value. Because there was no other information, the diagram of [82Vil] is accepted tentatively. Based on a pressure-temperature diagram, [64Kil] considered InNb3 to be metastable at room temperature. However, the extrapolation is rather arbitrary, and it is quite possible that InNb3 falls in the stable region at room temperature, as indicated by an equally probable extrapolation to 1 bar. In fact, [64Jei] and [82Vil] were able to prepare InNb3 under 1 bar pressure at above room temperature. The superconducting transition temperature of InNb3 is 9.2 K [62Ban] or 9.28 [68Ott]. A cast alloy containing 67 at.% Nb homogenized at 1050 C for 1.5 days included a W-type phase in addition to (In) and (Nb), which are expected from the phase diagram [65Ram]. The details of this phase are unknown. 62Ban: M.D. Banus, T.B. Reed, H.C. Gatos, M.C. Lavine, and J.A. Kafalas, J. Phys. Chem. Solids, 23, 971-973 (1962). 64Jei: W. Jeitchko, H. Nowotny, and F. Benesovsky, Monatsh. Chem., 95(4/5), 1040-1043 (1964) in German. 64Kil: D.H. Killpatrick, J. Phys. Chem. Solids, 25, 1213-1216 (1964). 65Ram: A. Raman and K. Schubert, Z. Metallkd., 56(1), 44-52 (1965) in German. 68Ott: G. Otto, Z. Phys., 215(4), 323-334 (1968) in German. 69Das: C. Dasarathy, Trans. Metall. Soc. AIME, 245(9), 2015-2019 (1969). 74Die: E.N. Dieva, Physicochemical Studies of Liquid Metals and Alloys, V.G. Bamburov, Ed., Izd. Ural'sk. Nauch. Tsentra Akad. Nauk SSSR, Sverdlovsk, 98- 104 (1974). 82Vil: P. Villars and K. Girgis, Z. Metallkd., 73, 169-171 (1982) in German. 83Cha: M.W. Chase, Bull. Alloy Phase Diagrams, 4(1), 123-124 (1983). Submitted to the APD Program. Complete evaluation contains 1 figure, 2 tables, and 8 references. 1