The third generation of rare earth permanent magnet NdFeB (NdFeB) magnets are the strongest contemporary performance permanent magnets, which not only has high remanence, high coercivity, high energy product, high cost performance characteristics, and easily processed into various sizes, are now widely used in aerospace, electronic, sound, instruments, jewelry, leather handbags, packing boxes, toys, medical technology and other aviation equipment required permanent magnetic device, especially for developing high-performance , smaller, lighter and a variety of replacement products.