High-coercivity iron-rich rare-earth permanent magnet material based on (Fe, Co)3B-Nd-M (M=Al, Si, Cu, Ga, Ag, Au)

Abstract

High-coercivity, high-remanence permanent magnet materials have been obtained via a crystallization treatment of amorphous (Nd,Dy)xFe 80.5-x-yCoyB18.5M1 alloys for 3≤x≤5 and 0≤y≤5, where M represent the additives Al, Si, Cu, Ga, Ag, and Au. It has been found that addition of Co and M results in a significant reduction of the crystal grain size and leads to significant improvements both in the intrinsic coercivity and in the energy product. The materials are superior to Nd2Fe14B-based rapidly solidified materials in the remanence Br, the temperature coefficient of Br, and magnetizability. The typical values of temperature coefficients of Br and HcJ are, respectively, -0.05%/K and -0.35% K. The magnetizing force required to obtain substantial remanence is approximately 0.8 MA/m. Compaction-molded resin-bonded magnets produced from these materials have magnetic performance (Br, HcJ) in the range between 0.89 T, 0.29 MA/m and 0.80 T, 0.35 MA/m.