Effects of Processing Conditions of a Ball‐Milled Fe₆₅Co₃₅ Soft Ferromagnetic Alloy on the Structural, Thermal, and Magnetic Properties

The Fe₆₅Co₃₅ alloy is a well‐known Fe‐based soft ferromagnetic alloy with excellent soft magnetic properties, which make it a strong candidate to be used in technological applications. In the present work, synthesizing nanoscrystalline Fe₆₅Co₃₅ alloy by mechanical alloying is focused on, adding cyclohexane (C₆H₁₂) acting as a process control agent (PCA). PCAs are effective in favoring nanostructured alloys with uniform grain size. The production of this type of alloy is a promising approach to tune the magnetic hardness in Fe₆₅Co₃₅. Structural, thermal, morphological, and magnetic properties have been studied after milling for 10, 25, and 50 h with and without the PCA. In the structural analysis, it is shown that the cubic α‐Fe(Co) phase is the predominant phase in all samples. The use of the PCA favors its nanocrystallinity; however, it slows Co diffusion into the Fe matrix. Thermal analysis detects an endothermic process between 525 and 575 °C in the samples milled with C₆H₁₂ only. This is associated with the transition of the residual Fe₃Co superlattice, to the stable α‐Fe(Co). The effect of the residual Fe₃Co at room temperature on the magnetic properties is twofold, by decreasing the saturation magnetization of Fe₆₅Co₃₅ but increasing both remanent magnetization and coercivity.