Rare earth permanent magnetic material is one of the important types of magnetic materials. It is a magnetic material prepared by integrating the alloy powder composed of mixed rare earth metals such as samarium and neodymium and transition metals (such as cobalt and iron) into tetragonal crystals by different processes and magnetizing by magnetic field. In 1967, the first generation of SmCo5 rare earth permanent magnet material came out, and the second generation of Sm2Co17 rare earth permanent magnet was successfully developed in the 1970s. Since the 1980s, the third generation neodymium permanent magnet material has become the most widely used variety in permanent magnet materials because of its excellent performance and low price; According to the statistics of Nonferrous Metals Industry Association and rare earth industry association, the output of Nd-Fe-B magnetic materials accounts for about 75% of the output of rare earth permanent magnetic materials.