The magnetic powder Sm 2 Fe 17 N x has recently garnered considerable interest due to its competitive pricing. In this study, the preparation of Sm 2 Fe 17 N x magnetic powder by melt quenching and nitriding process was successfully completed. In order to obtain a higher coercivity, the particle size of the magnetic powder was reduced to a diameter of less than 2 μm through ball milling. It was observed that as the ball milling time was extended, the coercivity of the magnetic powder exhibited a decline that was premature in comparison to the expected results. Additionally, the presence of minute particles of magnetic powder may appear spontaneous combustion phenomenon. Accordingly, Sm 2 Fe 17 N x magnetic powder with high coercivity ( H cj = 842.8 kA/m) was prepared by phosphoric acid passivation process. Through XRD patterns, it was found that the phosphoric acid passivation process markedly enhanced the antioxidant capacity of the magnetic powder. Through SEM images, it is found that the fine magnetic powder exhibits a sheet structure and has strong shape anisotropy. The research indicate that the phosphoric acid passivation process is effective in enhancing the stability of Sm 2 Fe 17 N x magnetic powder and inhibiting the oxidation reaction of magnetic powder during use. This has a beneficial impact on the service life of permanent magnet devices in industrial production.
Sm 2 Fe 17 N x magnetic powder was prepared by melt quenching and nitriding process. • Passivation treatment can enhance the strongest comprehensive magnetic properties of magnetic powder. • Passivation treatment enhances the high-temperature antioxidant capacity of magnetic powder. With the wide application of Sm 2 Fe 17 N x magnetic powder, it is necessary to enhance the antioxidant capacity of this magnetic powder. In this study, Sm 2 Fe 17 N x magnetic powder was successfully prepared via the strip casting method. To improve its antioxidant capacity, the surface of Sm 2 Fe 17 N x magnetic powder was passivated using phosphoric acid of different contents. The results indicate that the passivation treatment can significantly improve the comprehensive magnetic properties of Sm 2 Fe 17 N x magnetic powder ( B r = 1.0 T, ( BH ) max = 84.31 kJ/m 3 ), enhance the intrinsic coercivity of the magnetic powder ( H cj = 563.77 kA/m), and endow it with excellent oxidation resistance in a room-temperature air environment. Meanwhile, a high-temperature antioxidant test was conducted on the phosphoric acid-passivated Sm 2 Fe 17 N x magnetic powder The results show that the passivated Sm 2 Fe 17 N x magnetic powder still exhibits good high-temperature oxidation resistance in an air environment at 200 °C. This finding holds guiding significance for reducing the application cost of Sm 2 Fe 17 N x magnetic powder and enabling the full utilization of its high Curie temperature in industrial production.
危险品化学品经营许可证（带存储）