Фазовая диаграмма системы Cu-Pm

К оглавлению: Другие диаграммы (Others phase diargams)


Cu-Pm (Copper-Promethium) P.R. Subramanian and D.E. Laughlin No assessed phase diagram is available for the Cu-Pm system. However, the general pattern of Cu-Pm phase relationships is expected to be compatible with those of the other Cu-light lanthanide systems [85Gsc]. Accordingly, the existence of Cu6Pm, Cu5Pm, Cu4Pm, Cu7Pm2, Cu2Pm, and CuPm is proposed, because of the presence of similar phases in the Cu-Ce, Cu-Pr, Cu-Nd, and Cu-Sm systems. Moreover, melting and eutectic temperatures in the Cu-lanthanide systems show a systematic variation across the lanthanide series. On this basis, invariant temperatures were estimated for the proposed Cu-Pm intermediate phases by interpolation of corresponding data for the Cu-Ce, Cu- Pr, Cu-Nd, and Cu-Sm systems. The interpolated invariant temperatures were then combined with thermodynamic modeling and systematics of Cu-lanthanide systems to derive the calculated Cu-Pm phase diagram. Because there is no experimental phase diagram information for the Cu-Pm system, the calculation of Cu-Pm phase relationships involved the following assumptions: terminal solid solubilities are negligible; the liquid behaves like a subregular solution; and eutectic and melting temperatures represent values interpolated from experimental data for the other Cu-lanthanide systems. On this basis, the Cu-Cu6Pm, Cu4Pm-Cu2Pm, and CuPm-aPm eutectic temperatures were estimated to be 870, 800, and 550 C, respectively. For a first approximation, the corresponding compositions were assumed to be close to 9, 25, and 70 at.% Pm, respectively. These compositions were inferred from the Cu- Ce, Cu-Pr, Cu-Nd, and Cu-Sm phase diagrams. The Cu-rich liquidus below 9 at.% Pm and the Pm-rich liquidus above 70 at.% Pm were calculated from thermodynamic data, and the remaining liquidus was estimated from systematics of Cu-lanthanide systems. 85Gsc: K.A. Gschneidner, Jr., private communication (1985). Published in Bull. Alloy Phase Diagrams, 9(3a), Jun 1988. Complete evaluation contains 1 figure, 4 tables, and 6 references. 1