Phosphoric acid passivation treatment improves the anti-oxidant capacity of Sm2Fe17Nx magnetic powder

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.