Thermal stability of anisotropic bonded magnets prepared by additive manufacturing

In this research, anisotropic NdFeB + SmFeN hybrid and NdFeB bonded magnets are additively printed in a polyphenylene sulfide (PPS) polymer binder. Printed NdFeB + SmFeN PPS bonded magnets displayed excellent magnetic properties (B-r [remanence] = 6.9 kG [0.69 T], H-cj [coercivity] = 8.3 kOe [660 kA/m], and BHmax [energy product] = 9.9 MGOe [79 kJ/m(3)]) with superior corrosion resistance and thermal stability. The anisotropic NdFeB bonded magnet shows a high coercivity of 14.6 kOe (1162 kA/m) with a BHmax of 8.7 MGOe (69 kJ/m(3)). The coercivity and remanence temperature coefficients for NdFeB + SmFeN hybrid bonded magnets are -0.10%/K and -0.46%/K, and for NdFeB bonded magnets are -0.14%/K and -0.53%/K in the range of 300-400 K, indicating that the hybrid bonded magnets are thermally stable. The average flux aging loss for hybrid magnets was also determined to be very stable over 2000 h at 448 K (175 degrees C) in air with 2.04% compared to that of NdFeB magnets with 3.62%.