New Technology of Making NdFeB by Sintering

Sintered NdFeB as a third-generation rare earth permanent magnet material, has been in rapid development since 1980's due to its broad industrial applications and high electromagnetic performance. Sintered NdFeB metal materials can easily be oxidized, so future efforts to improve their antioxidative stability are required and the study of new manufacturing technology and new technology is necessary. At present, the traditional technology of sintering NdFeB is discussed, together with the processing technology of powder preparation, hydroforming and vacuum sintering. The article focuses on the milling and forming process, including the traditional ball mill to hydrogen explosion, air grinding powder, and dry magnetic field molding to wet pressure magnetic field oriented molding, to prevent the production process of oxidation, thereby enhancing the electromagnetic properties and their anti-corrosion antioxidant capacity. During the NdFeB sintering process, content of oxygen is regulated to control the phase change. As a result, electromagnetic properties of sintered NdFeB obtained a qualitative leap.