METHOD FOR IMPROVING MAGNETIC PROPERTIES OF SINTERED NEODYMIUM-IRON-BORON THIN-SHEET MAGNET

文件类型：PDF文档
文件大小：912K
Provided is a method for improving magnetic properties of a sintered neodymium-iron-boron thin-sheet magnet. A powder containing a rare earth element is coated on the surface of the sintered neodymium-iron-boron thin-sheet magnet to form a surface coating layer, and then a diffusion treatment and an aging treatment are carried out to allow the rare earth element in the coating layer to enter into the interior of the sintered neodymium-iron-boron thin-sheet magnet. The powder containing a rare earth element is a mixture of a powder of a rare earth oxide and a powder of a hydrogen storage alloy hydride. The advantages of the method are that an oxidation-reduction reaction is carried out between the rare earth oxide and the hydrogen storage alloy hydride, the rare earth element is reduced, and hydrogen is released from the hydrogen storage alloy hydride during the diffusion treatment, thus the diffusion efficiency of the rare earth element is remarkably improved, and the diffusion depth of the rare earth element is increased, such that the difference in the contents of the rare earth element at different positions in the interior of the sintered neodymium-iron-boron thin-sheet magnet is narrowed, the coercive force is obviously increased and at the same time the residual magnetism reduction is ensured to be not obvious. Moreover, mass production can be performed, and the squareness of the final sintered neodymium-iron-boron thin-sheet magnet will not be affected.