Interface engineering constructs oxide composite bulk γ′-Fe4N magnetic alloys with high resistivity: superior magnetization and manufacturability

• Published in: Journal of materials science & technology 2024-03, Vol.175, p.212-222
• Main Authors: Li, Wanjia, Li, Wangchang, Ying, Yao, Yu, Jing, Zheng, Jingwu, Qiao, Liang, Li, Juan, Che, Shenglei
• Format: Article
• Language: English
• Subjects: Composite γ'-Fe4N bulk; Nitriding mechanism; Resistivity; Saturation magnetization; SPS
• ISSN: 1005-0302
• DOI: 10.1016/j.jmst.2023.07.033

•A novel γ′-Fe4N based soft magnetic material with high resistance and high saturation magnetization was fabricated through the SPS process.•The nitriding mechanism under various nitriding temperature and nitriding time was explored, and the evolution of nitrogen and oxygen content and magnetic properties with nitriding temperature and nitriding time were investigated.•A high resistance oxide interface composed of ZnO or TiO2 was established in the γ′-Fe4N bulk magnetic material through a series of pre-calcination, reduction, and nitridation steps. ZnO doped γ′-Fe4N bulk material has a maximum resistivity of 220 μΩ·cm, accompanied by a high Ms of 156.02 emu/g. While the TiO2 doped γ'-Fe4N exhibits a remarkable resistivity of 379 μΩ·cm and a Ms of 149.7 emu/g. In addition, oxide interface engineering can well block the formation of ε-Fe3N phase, so as to better maintain the excellent magnetic properties.•The innovative design concept of this novel γ′-Fe4N based soft magnetic material has opened up new possibilities for the development of soft magnetic materials with exceptional electrical and magnetic properties, which provides a promising path towards the creation of a new generation of soft magnetic materials for the advanced power equipment. Soft magnetic material with high saturation magnetization (Ms) and high resistance (ρ) is vital to improve the power density and conversion efficient of modern electrical magnetic equipment. Yet, increasing Ms is always at the expense of high resistivity, such as soft magnetic alloys substitute for the ferrite. In this work, the superior comprehensive electromagnetic properties, namely the close association of high saturation magnetization and high resistivity, are combined in a new way in a newly Fe-N based magnetic materials. A high resistance oxide interface engineering was constructed between the conducting ferromagnetic phases in the process of spark plasma sintering (SPS) to achieve superior electromagnetic properties. The ZnO composite γ'-Fe4N bulk has a maximum resistivity of 220 μΩ cm and a Ms of up to 156.02 emu/g, while the TiO2 composite γ'-Fe4N bulk has a maximum resistivity of 379 μΩ cm and a Ms of 149.7 emu/g. The research findings offer valuable insights for the advancement of the next generation of soft magnetic materials, which hold significant potential for use in high-frequency, high-efficiency, and energy-saving power equipment applications. [Display omitted]