Manufacturing method of rare earth permanent magnet

Abstract

The invention discloses a manufacturing method of a rare earth permanent magnet. The method comprises following steps: firstly, preparing raw materials of the rare earth permanent magnet into rare earth permanent magnet green bodies with thickness sizes of 1-15MM through a compression moulding technology; then, coating coating layers with heavy rare earth elements on the surfaces of the rare earth permanent magnet green bodies; and finally successively carrying out sintering processing and aging processing to the rare earth permanent magnet green bodies with the coating layers. The method is advantaged by that mechanical processing and surface preprocessing are unnecessarily carried out; the technology for heating processing is carried out only once; the process is simple; the production efficiency is clearly improved; the production process cost is reduced; batch production is easy in realization; the rare earth permanent magnet is moulded by once sintering; the product conformity is relatively high; in the sintering process, the heavy rare earth elements in the coating layers on the surfaces of the rare earth permanent magnet green bodies are diffused to the crystal boundary phase and the main phase crystal grain epitaxial layer of the rare earth permanent magnet; the coercive force is improved to a much greater extent on the premise of hardly reducing the residual magnetism; the application amount of the heavy rare earth is little; and the cost is low.

Description

technical field [0001] The invention relates to a manufacturing technology of a rare earth permanent magnet, in particular to a manufacturing method of a rare earth permanent magnet. Background technique [0002] In the current production and life of human society, with the continuous advancement of science and technology, rare earth permanent magnets (that is, sintered NdFeB magnets) have penetrated into many fields of industry, civil facilities, office automation and scientific research, and some high-tech fields , such as robots, precision machine tools, high-precision instruments, automotive motors and various permanent magnet motor industries, the demand for high-performance rare earth permanent magnets is also rapidly expanding. In the traditional production process of preparing high-performance rare earth permanent magnets, it is necessary to add a large amount of heavy rare earth elements to the rare earth permanent magnets. Although this process can improve the coer...

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Problems solved by technology

Although the second type of method can improve the coercive force of rare earth permanent magnets and only needs one heat treatment compared with the first type of method, because the heavy rare earth elements are directly added to the magnetic powder raw materials, the heavy rare earth elements will be diffused in the grain boundary process. In the case of direct diffusion into the main phase of the rare earth permanent magnet, the remanence is greatly reduced

Compared with the first method, the third method combines the grain boundary diffusion treatment and sintering treatment into one step, omitting one heat treatment process, but two pressing processes are required, and the cladding layer contains Cu powder, which is easy to process during the pressing process. Due to the uneven distribution of Cu powder, the performance of the magnet is inconsistent, so that the consistency of product performance cannot be guaranteed, so mass production cannot be carried out

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