Effect of antioxidants on the efficiency of jet milling and the powder characteristics of Sm₂Co₁₇ permanent magnets

This study investigated the effect of antioxidants on the grinding efficiency, magnetic powder characteristics, microstructure, and magnetic properties of 2:17 type SmCo permanent magnet materials. The results show that adding antioxidants helps improve the dispersion among magnetic powders, leading to a 33.3% decrease in jet milling time and a 15.8% increase in magnet powder production yield. Additionally, adding antioxidants enhances the oxidation resistance of the magnetic powders. After being stored in a constant temperature air environment at 25 °C for 48 h, the O content in the powder decreased by 33% compared to samples without antioxidants. While in the magnet body, the O content decreased from 0.21 wt.% to 0.14 wt.%, which helps increase the effective Sm content and domain wall pinning uniformity in the magnet. Excellent magnetic properties were obtained in the magnet with added antioxidants: B_r = 11.6 kGs, SF = 79.6%, H_cj = 16.8 kOe, and (BH)_max = 32.5 MGOe.