A method for improving the magnetic efficiency of a sintered ndfeb - lamellar magnet

摘要

Is provided a process for improving the magnetic properties of a sintered neodymium - iron - boron - lamellar magnet. A powder which contains a rare earth element, is applied to the surface of the sintered neodymium - iron - boron - lamellar magnet is applied, in order to form a surface coating layer, and then, a diffusion heat treatment and an aging treatment is carried out in order that the rare earth element in the coating layer to permit, in the interior of the sintered neodymium - iron - boron - lamellar magnet to penetrate. The powder, which contains a rare earth element, is a mixture of a powder of a rare earth metal oxide and a powder of a water material memory alloy hydride. The advantages of the process are in the fact that an oxidizing agent - reduction - reaction between the rare earth oxide and the water storage alloy hydride material is carried out, said rare earth element is reduced and thus, during the hydrogen diffusion heat treatment substance from the water storage alloy hydride is released, so that the diffusion efficiency of the rare earth element it is improved and the depth of diffusion of the rare earth element, is increased, so that the difference in the contents of the rare earth element at various positions in the interior of the sintered neodymium - iron - boron, thin layer magnet is reduced, obviously, the coercive force is increased and, at the same time, it is ensured that the reduction of the residual magnetism is not essential. In addition, a mass production can be carried out, and the squareness of the finished sintered neodymium - iron - boron - lamellar magnet is not impaired.