Фазовая диаграмма системы Si-Sm

К оглавлению: Другие диаграммы (Others phase diargams)

Si-Sm (Silicon-Samarium) A.B. Gokhale and G.J. Abbaschian The assessed Sm-Si equilibrium diagram is based in part on the work of [64Cop] and partially on the data from several investigations not directly related to the phase equilibria, but pertaining to the crystal structures of the intermediate phases in the system. The liquidus has been sketched by the present evaluators, based on an assumed similarity of interaction of Si with the RE elements. [64Cop] carried out a partial determination of the phase equilibria on the Sm- rich side (up to 37.5 at.% Si) by metallographic, thermal, and X-ray phase analysis. They reported the presence of a eutectic reaction between (Sm) and Sm5Si3 at 880 C and 15.5 at.% Si. They also indicated the solid solubility of Si in (Sm) to be less than 1 at.%, but did not determine the liquidus, nor did they determine the melting temperature and characteristics of Sm5Si3. The Sm-Si liquidus is based on the Nd-Si system for two reasons: (1) Nd is close to Sm in atomic number; and (2) the liquidus in the Nd-Si system has been determined reliably by [84Ere]. Thus, SmSi and SmSi2 are indicated to melt congruently, whereas Sm5Si3 and Sm5Si4 are shown to form peritectically. In addition, three eutectic reactions-L = (Sm) + Sm5Si3, L = SmSi + SmSi2, and L = (Si) + SmSi2-are included, and Sm3Si5 is shown to decompose peritectoidally. An additional intermediate phase (Nd3Si4) is present in the Nd-Si system, but it decomposes peritectoidally, and is therefore unlikely to affect the shape of the liquidus. 59Per: J.A. Perri, I. Binder, and B. Post, J. Phys. Chem., 63, 616-619 (1959). 64Cop: M. Copeland and H. Kato, Physics and Material Problems in Reactor Control Rods, IAEA, Vienna (1964). 65Gla: E.I. Gladyshevskii and P.I. Kripyakevich, Izv. Akad. Nauk SSSR, Neorg. Mater., 1(5), 702-705 (1965) in Russian. 65Par: E. Parthe, D. Hohnke, W. Jeitschko, and O. Schob, Naturwissenschaften, 52(7), 155 (1965). 66Hoh: D. Hohnke and E. Parthe, Acta Crystallogr., 20, 572-582 (1966). 67Ram: A. Raman, Z. Metallkd., 58, 179-184 (1967). 67Smi: G.S. Smith, A.G. Tharp, and Q. Johnson, Acta Crystallogr., 22, 940-943 ( 1967). 84Ere: V.N. Eremenko, K.A. Meleshevich, Yu.I. Buyanova, and I.M. Obushenko, Dop. Akad. Nauk Ukr. RSRA, 11, 77-82 (1984) in Ukrainian. Published in Bull. Alloy Phase Diagrams, 9(5), 1988. Complete evaluation contains 4 figures, 4 tables, and 20 references. 1