摘要
The Fe69.5-xNd7 B21Nb2.5Gax(x = 0-1)permanent magnets in the form of rods were prepared by annealing the bulk amorphous alloys.The magnetic properties,phase evolution and microstructure of the alloys were investigated systematically.It is found that the glass forming ability(GFA), microstructure and magnetic properties are sensitive to Ga content for Fe69.5-xNd7 B21Nb2.5Gax(x = 0-1)bulk alloys.The annealed alloys are mainly composed of soft α-Fe,hard Nd2 Fe14B and nonmagnetic Nd1.1Fe4 B4 phases.When x = 0.3,the optimally annealed magnets exhibit magnetic properties of the remanence Br = 0.63 T,intrinsic coercivity Hcj = 368.68 kA/m and maximum energy product(BH)max = 33.73 kJ/m3.Furthermore,magnetic field heat treatment at the temperature close to Curie temperature of Nd2 Fe14B phase was applied to the annealed Fe69.2Nd7 B21Nb2.5Ga0.3 magnet.The results of X-ray diffraction(XRD)and transmission electron microscopy(TEM)indicate that the magnetic field heat treatment can be beneficial for the precipitation of α-Fe.Thus,the Br,Hcj and(BH)max are enhanced by 8.7%,6.3% and 16.3%,respectively.
The Fe69.5-xNd7 B21Nb2.5Gax（x = 0-1）permanent magnets in the form of rods were prepared by annealing the bulk amorphous alloys.The magnetic properties,phase evolution and microstructure of the alloys were investigated systematically.It is found that the glass forming ability（GFA）, microstructure and magnetic properties are sensitive to Ga content for Fe69.5-xNd7 B21Nb2.5Gax（x = 0-1）bulk alloys.The annealed alloys are mainly composed of soft α-Fe,hard Nd2 Fe14B and nonmagnetic Nd1.1Fe4 B4 phases.When x = 0.3,the optimally annealed magnets exhibit magnetic properties of the remanence Br = 0.63 T,intrinsic coercivity Hcj = 368.68 kA/m and maximum energy product（BH）max = 33.73 kJ/m3.Furthermore,magnetic field heat treatment at the temperature close to Curie temperature of Nd2 Fe14B phase was applied to the annealed Fe69.2Nd7 B21Nb2.5Ga0.3 magnet.The results of X-ray diffraction（XRD）and transmission electron microscopy（TEM）indicate that the magnetic field heat treatment can be beneficial for the precipitation of α-Fe.Thus,the Br,Hcj and（BH）max are enhanced by 8.7%,6.3% and 16.3%,respectively.
基金
Project supported by the National Natural Science Foundation of China(51471101)
