摘要
The magnetic properties,microstructure and magnetic hardening of sintered (Nd_(1-x)Dy_x)_(16)Fe_(77.2)B_(6.8) and Nd_(16)Fe_(77.2)B_(6.8)+ywt-%Dy_2O_3 magnets have been stud- ied.As an addition of Dy to the magnet during smelting,Dy atoms may enter the matrix phase Nd_2Fe_(14)B,so as to enhance H_A,refine grains and improve boundary struc- ture,as well as to increase H_(ci)of the magnet.If Dy_2O_3 is added to powder material prior to sintering,Dy atoms diffuse into the epitaxial layer of grains of matrix phase causing enhancement of K′_1,also refinement of grains and improvement of boundary structure.The NdFeB based permanent magnets with higher H_(ci) and greater(BH)_m may be produced by adding about 2—3 wt-% Dy_2O_3 which make a favourable condition for lower cost.
The magnetic properties,microstructure and magnetic hardening of sintered (Nd_(1-x)Dy_x)_(16)Fe_(77.2)B_(6.8) and Nd_(16)Fe_(77.2)B_(6.8)+ywt-%Dy_2O_3 magnets have been stud- ied.As an addition of Dy to the magnet during smelting,Dy atoms may enter the matrix phase Nd_2Fe_(14)B,so as to enhance H_A,refine grains and improve boundary struc- ture,as well as to increase H_(ci)of the magnet.If Dy_2O_3 is added to powder material prior to sintering,Dy atoms diffuse into the epitaxial layer of grains of matrix phase causing enhancement of K′_1,also refinement of grains and improvement of boundary structure.The NdFeB based permanent magnets with higher H_(ci) and greater(BH)_m may be produced by adding about 2—3 wt-% Dy_2O_3 which make a favourable condition for lower cost.
