Phase equilibria in the Co–Fe–La ternary system have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Isothermal sections at 600 (in the whole concentration region) and 500 °C (in the La-rich region) for this system have been constructed. It was shown that the ternary compound La₂(Co,Fe)₁₇ (τ) (Th₂Zn₁₇-type structure) is stable at 600 °C and has homogeneity range from 67 to 72 at.% Co. It co-exists with the majority of solid phases (αFe,Co), LaCo₁₃, LaCo₅, La₂Co₇ and La₂Co₃ at 600 °C. The LaCo₁₃ phase has the widest homogeneity region and dissolves up to 32.5 at.% Fe at 600 °C. The character of phase equilibria at 500 °C in the studied region is similar to those at solidus temperature. The character of phase equilibria at 600 °C is different from those at the solidus temperature. The main difference involves the fact that the equilibrium τ + LaCo₅ which is present in the Co–Fe–La system at solidus temperature, is absent at 600 °C. Instead, the alternative equilibrium (αFe,Co) + La₂Co₇ is present at 600 °C.

使用X射线衍射（XRD），扫描电子显微镜（SEM）和电子探针显微分析（EPMA）研究了Co-Fe-La三元体系中的相平衡。已经为该系统构建了600（在整个浓度区域）和500°C（在La富集区域）的等温截面。结果表明，三元化合物La ₂（Co，Fe）₁₇（τ）（Th ₂ Zn ₁₇型结构）在600°C下稳定，并且Co的均质度为67至72 at。％。在600°C下具有大多数固相（αFe，Co），LaCo ₁₃，LaCo ₅，La ₂ Co ₇和La ₂ Co ₃。LaCo ₁₃相具有最宽的均匀性区域，并且在600°C时可溶解高达32.5 at。％的Fe。研究区在500°C时的相平衡特性与固相线温度相类似。600°C下的相平衡特性与固相线温度下的相平衡特性不同。主要区别在于以下事实：在固相线温度下，Co–Fe–La系统中不存在平衡τ+ LaCo ₅，但温度为600°C。相反，替代平衡（αFe，Co）+ La ₂ Co ₇在600°C存在。