Effect of Nb content on Sm₂Fe_17−xNb_x and its nitrides prepared by reduction-diffusion method

In this paper, Sm₂Fe_17−xNb_xN₃ magnetic powder was prepared by reduction-diffusion reaction and the content of Nb-Fe was controlled during the preparation process. By observing the microstructure of Sm₂Fe_17−xNb_x alloys and Sm₂Fe_17−xNb_xN₃, the magnetic properties of Sm–Fe–N alloys doped with different contents of Nb were investigated. The results show that the introduction of Nb can not only refine and homogenize the grains of Sm-Fe alloys to a certain extent, but also inhibit the formation of α-Fe during the nitriding process of Sm–Fe alloys. In addition, the introduction of Nb makes Sm-Fe alloy show better nitriding effect. Thus, the coercivity of Sm₂Fe_17−xNb_xN₃ powder is significantly improved. In this study, when x = 0.4, Nb has the best inhibitory effect on α-Fe in the reduction-diffusion process. The Sm₂Fe_17−xNb_xN₃ magnetic powder prepared under this condition has the highest intrinsic coercivity, which is 803.56 kA/m. When the value of x is in the range of 0.2 to 0.4, Nb has the greatest contribution to the magnetic properties of the prepared Sm₂Fe_17−xNb_xN₃ powder.