Фазовая диаграмма системы Cu-Eu

К оглавлению: Другие диаграммы (Others phase diargams)

Cu-Eu (Copper-Europium) P.R. Subramanian and D.E. Laughlin The present assessment of the Cu-Eu system is based primarily on the recent phase diagram investigation of [85Cos], who reported the existence of four intermediate phases: Cu5Eu, Cu2Eu, CuEu, and CuEu2. The Cu-Eu phase diagram of [85Cos] is based on DTA, metallography, and X-ray analysis. Thermal analyses were carried out using several thermal cycles with varying heating and cooling rates to ensure reproducibility. Eu is chemically very active, and according to [85Cos], alloys containing >30 at.% Eu are oxidizable in air, the tendency to oxidize decreasing with increasing Cu content. The phase diagram of the Cu-Eu system deviates from the systematics of Cu with the other light lanthanides in that the phases Cu6Eu and Cu4Eu are absent, Cu5Eu melts congruently, and Cu2Eu melts peritectically. In contrast, it is observed that in the other light lanthanides, the 6:1 as well as the 4:1 phases do occur, and in addition, the 5:1 phases melt peritectically, and the 2:1 phases melt congruently. These differences are attributable to the fact that Eu is one of the two lanthanides that are divalent in the standard state. [85Cos] concluded that the solid solubility of Cu in (Eu) is negligible, because the lattice parameter of Eu does not change significantly upon alloying with Cu. Similarly, there is no evidence of any terminal solid solubility of Eu in (Cu). 85Cos: G.A. Costa, E.A. Franceschi, and A. Tavansi, J. Less-Common Met., 106, 175-182 (1985). Published in Bull. Alloy Phase Diagrams, 9(3a), Aug 1988. Complete evaluation contains 2 figures, 6 tables, and 18 references. Special Points of the Cu-Eu System