Sintered NdFeB permanent magnet contains basic raw materials neodymium (ND) 32%, iron (Fe) 64%, boron (B) 1%, , with small amount of dysprosium (Dy), terbium (Tb), cobalt (Co), niobium (Nb), gallium (Ga), aluminum (Al), copper (Cu) and other elements, Sintered NdFeB permanent magnetic materials with the high remanence, high coercivity, and was known as the " Magnetic King" The main characteristics of permanent magnetic materials is: Good magnetic properties, high temperature performance. High Curie temperature, up to 710 ~ 880 degrees Celsius, the maximum operating temperature up to 250 ~ 350 degrees Celsius. So the stability of permanent magnet magnetic material is best, it is suitable for manufacturing various high-performance permanent magnet electro-acoustic devices.