Фазовая диаграмма системы Eu-Mg

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Eu-Mg (Europium-Magnesium) A.A. Nayeb-Hashemi and J.B. Clark The equilibrium phases of the Mg-Eu system are (1) the liquid; (2) the terminal (Mg) and (Eu) phases, with undetermined maximum solid solubilities; ( 3) two congruently formed intermetallic compounds, Mg17Eu2 and Mg2Eu; and (4) two peritectically formed intermetallic compounds, ~Mg5Eu and MgEu. The assessed phase diagram is based primarily on the experimental data of [ 69Muh]. The shape of the (Mg) and (Eu) liquidus is questionable because of insufficient experimental data. The (Eu) liquidus is shown as a dashed line, and the liquidus curves around the melting points of Mg17Eu2 and Mg2Eu have been adjusted slightly. MgEu forms by a peritectic reaction, L + Mg2Eu = MgEu, at 463 C. The thermal analysis data of [69Muh] between 33.33 and 66.2 at.% Eu show evidence of both the suppression of the peritectic reaction for the formation of MgEu and the consequent presence of a metastable eutectic reaction. In the composition range 60 to 65 at.% Eu, [69Muh] showed liquidus arrests that appeared to be the result of severe undercooling. Thus, the temperatures of the metastable and the stable eutectic reactions are apparently very close to each other. In Mg2Eu and Mg17Eu2 compounds between 90 and 295 K, the effective magnetic moments increased with increasing temperature [68Kle]. [78Bus] investigated the magnetic properties of Mg2RE compounds in the temperature range 1.8 to 300 K and in magnetic fields up to 18 kOe. Mg2Eu was found to order antiferromagnetically, with the N‚el temperature at 30 K. According to [79Gra], Mg5Eu and Mg17Eu2 showed magnetic ordering, with N‚el temperatures at 7.8 and 7.9 K, respectively. Above 20 K, Mg5Eu showed Curie-Weiss behavior, and at low temperatures, magnetic ordering of the antiferromagnetic type occurred [81Lue]. 68Kle: W. Klemm and W. Muhlpfordt, Rev. Chim. Mineral., 5, 561-567 (1968) in German. 69Muh: W. Muhlpfordt and W. Klemm, J. Less-Common Met., 17, 127-129 (1969) in German. 78Bus: K.H.J. Buschow, R.C. Sherwood, and F.S.L. Hsu, J. Appl. Phys., 49(3), 1510-1512 (1978). 79Gra: H. Graaf, W.J. Huiskamp, R.C. Thiel, and H.Th. LeFever, Physica, 98B, 60-64 (1979). 81Lue: H. Lueken, J. Less-Common Met., 79, 151-156 (1981) in German. Published in Phase Diagrams of Binary Magnesium Alloys, 1988. Complete evaluation contains 1 figure, 4 tables, and 15 references. Special Points of the Mg-Eu System