Фазовая диаграмма системы Cu-Tm

К оглавлению: Другие диаграммы (Others phase diargams)

Cu-Tm (Copper-Thulium) P.R. Subramanian and D.E. Laughlin There is no experimental phase diagram information on the Cu-Tm system other than a solubility study by [75Boc]. However, the general features of the Cu-Tm phase diagram are expected to be similar to those of the other Cu-heavy lanthanide systems [85Gsc]. Moreover, melting and eutectic temperatures in the Cu-lanthanide systems, in general, are known to vary systematically across the lanthanide series. Therefore, the phase diagram for the Cu-Tm system was estimated from extrapolation of corresponding invariant temperature data for those Cu-lanthanide systems for which experimental phase diagrams are already known, using the methods described by [83Gsc], in conjunction with thermodynamic modeling. In the calculated diagram, the existence of Cu9Tm2 and Cu7Tm2 is proposed solely on the basis of the presence of similar phases in the Cu-Gd [83Car], Cu-Dy [82Fra], and Cu-Er [70Bus] systems. No thermodynamic data are available for the Cu-Tm system. The calculation of the Cu-Tm phase relationships, therefore, involved the following assumption: the liquid behaves like a subregular solution; terminal solid solubilities are negligible; and eutectic and melting temperatures represent values extrapolated from experimental data for the other Cu-lanthanide systems. In the modeling, the terminal eutectic temperatures were kept fixed, but the eutectic compositions were allowed to vary within 3 at.% to provide a good fit. The Cu-rich and Tm-rich liquidus were calculated from thermodynamic data, and the remaining liquidus was estimated from systematics of Cu-lanthanide systems. [75Boc] reported a maximum solubility of Tm in (Cu) between 0.05 and 0.07 wt.% Tm (0.02 and 0.03 at.% Tm) at the Cu-rich eutectic temperature; the eutectic temperature was reported to lie between 850 and 870 C. Amorphous thin films with the composition Cu0.39Tm0.61 were prepared by [79Mcg] by sputtering from arc-melted specimens, and by thermal evaporation from Cu and Tm targets, followed by condensation from Cu and Tm targets, followed by condensation on liquid nitrogen-cooled sapphire substrates. 63Sto: A.R. Storm and K.E. Benson, Acta Crystallogr., 16, 701-702 (1963). 64Cha: C.C. Chao, H.L. Luo, and P. Duwez, J. Appl. Phys., 35, 257-258 (1964). 65Ian: A. Iandelli and A. Palenzona, J. Less-Common Met., 9, 1-6 (1965). 69Bus: K.H.J. Bushchow, A.S. van der Goot, and J. Birkhan, J. Less-Common Met., 19, 433-436 (1969). 75Boc: N.R. Bochvar and E.V. Lysova, Rare-Metals in Non-Ferrous Alloys, Nauka, Moscow, 12-16 (1975). 79Mcg: T.R. McGuire and R.J. Gambino, J. Appl. Phys., 50(11), 7653-7655 (1979). 82Fra: E. Franceschi, J. Less-Common Met., 87, 249-256 (1982). 83Gsc: K.A. Gschneidner, Jr., and F.W. Calderwood, Bull. Alloy Phase Diagrams, 4(2), 129-131 (1983). 85Gsc: K.A. Gschneidner, Jr., private communication (1985). Published in Bull. Alloy Phase Diagrams, 9(3a), Aug 1988. Complete evaluation contains 1 figure, 5 tables, and 16 references. Special Points of the Cu-Tm System