The isothermal section of the phase diagram of the La–Ni–Cu ternary system at 673 K

Abstract

The isothermal section of the phase diagram of the ternary system La–Ni–Cu has been investigated by X-ray diffraction, differential thermal analysis, optical microscopy and electron microscopy techniques. It consists of 13 single-phase regions, 23 two-phase regions and 11 three-phase regions. At 673 K, the maximum solid solubility of Cu in La 2Ni 7, LaNi 3, La 7Ni 16, La 2Ni 3 and LaNi is about 2, 2, 3, 3 and 5 at.% Cu, respectively. The solid solubility of Cu in La 7Ni 3 and Ni in LaCu 6 is too small to observe. Cu and Ni can replace each other in LaNi 5 and LaCu 5, the LaNi 5 and LaCu 5 form a continuous solid solution. The maximum solid solubility of Ni in LaCu 2 and LaCu is about 15 and 4at.% Ni, respectively. A new ternary compound La 10Cu 85Ni 5 has been observed in the La–Ni–Cu ternary system.