The ternary phase diagram La-Ni-Fe was studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Three isothermal sections, at 750, 600 and 500 °C were constructed covering the whole concentration range. In addition, vertical sections at 15 and 35 at.% La were evaluated based on the abovementioned methods and DTA analysis. Among binary compounds, LaNi₅, La₅Ni₁₉ and La₂Ni₇ have the widest homogeneity regions. The LaNi₅ phase dissolves 19.9, 19.6 and 19.4 at.% Fe at 750, 600 and 500 °C, respectively. The solubility of Fe in La₅Ni₁₉ is 14.5, 12.1 and 8.9 at.% at 750, 600 and 500 °C, respectively. For the La₂Ni₇ phase, the Fe-solubility was found to be 13.9, 11.3 and 10.1 at.% at 750, 600 and 500 °C, respectively. The homogeneity regions of the remaining phases are much smaller. The character of phase equilibria at 750 °C in the Ni-rich region is similar to those at solidus temperature. The character of the phase equilibria at 600 and 500 °C, however, differs from those at higher temperatures. In particular, the equilibrium (γFe,Ni) + La₅Ni₁₉ which is present in the La-Ni-Fe system at solidus temperature and 750 °C, is absent at 600 and 500 °C. Instead, the alternative equilibrium LaNi₅ + La₂Ni₇ is present at 600 °C. Furthermore, the equilibrium La₂Ni₇ + La₂Ni₃ which is present at solidus temperature, is replaced by the alternative equilibrium (αFe) + La₇Ni₁₆ at lower temperatures.

使用 X 射线衍射 (XRD)、扫描电子显微镜 (SEM) 和电子探针微量分析 (EPMA) 研究了 La-Ni-Fe 三元相图。在 750、600 和 500 °C 下构建了三个等温段，覆盖了整个浓度范围。此外，基于上述方法和 DTA 分析评估了 15 和 35 at.% La 的垂直截面。在二元化合物中，LaNi ₅、La ₅ Ni ₁₉和La ₂ Ni ₇具有最宽的均质区。LaNi ₅相在 750、600和 500 °C 下分别溶解 19.9、19.6 和 19.4 at.% Fe。Fe在La ₅ Ni _19中的溶解度在 750、600 和 500 °C 下分别为 14.5、12.1 和 8.9 原子％。对于 La ₂ Ni ₇相，发现在 750、600 和 500 °C 下的 Fe 溶解度分别为 13.9、11.3 和 10.1 at.%。其余相的均匀区域要小得多。750 °C 下富镍区的相平衡特征与固相线温度下的相平衡特征相似。然而，600 和 500 °C 下的相平衡特征与更高温度下的相平衡特征不同。特别是，在固相线温度和 750 °C 下存在于 La-Ni-Fe 系统中的平衡 (γFe,Ni) + La ₅ Ni ₁₉在 600 和 500 °C 时不存在。相反，替代平衡 LaNi ₅  + La ₂ Ni ₇存在于 600 °C。此外，在固相线温度下存在的平衡 La ₂ Ni ₇  + La ₂ Ni ₃在较低温度下被替代平衡 (αFe) + La ₇ Ni ₁₆所取代。