Synthesis of γ′-Fe₄N soft magnetic material by high-pressure nitriding approach

A novel synthesis approach was developed to prepare nanoscale γ′-Fe₄N in this paper. Starting from iron powder, high-power ball milling process was conducted at room temperature to create nanocrystalline Fe powder. The milled powder was nitridized in a high-pressure environment. A post-annealing step was followed to anneal the sample, activate the nitrogen atoms, and crystallize the sample. Finally, the prepared sample was characterized by X-ray diffraction, vibrating sample magnetometer, and transmission electron microscope to show its crystalline and magnetic properties. The prepared γ′-Fe₄N powder is compacted into a disk shape to testify its application feasibility in the field of the power transformer. The material showed excellent soft magnetic properties, high saturation magnetization, low coercivity, high electrical resistivity, and high thermal stability up to 640 °C. The proposed approach could have potential application in large volume production of the γ′-Fe₄N soft magnetic material.