Study On Processing Sintering Nd-Fe-B Permanent Magnets With High Performance

With development of20years sintered Nd-Fe-B permanent magnets, technology matures increasingly, and have been widely used in industrial, defense, medical, communications, computer, transportation, household appliances and green energy. Domestic enterprises can produce large quantities of magnetic energy product of358～400KJ/m3, which is more and more close to overseas corporation. However, technology and equipment drop behind, manufacturing high-performance(high magnetic energy product and the coercivity), consistency, stability, low cost of Nd-Fe-B magnets is still the direction of research.This article describes a lot of new technologies on the basis of the traditional preparation process, quick-setting strip casting process impacts on the alloy grain size in the different cooling rate, and the microstructure of alloy cast piece influences on microstructure and magnetic properties of sintered Nd-Fe-B magnets. And adding Gd and Ho in the Nd-Fe-B alloys can promote the growth of Nd2Fe14B columnar crystal, make Nd-rich phase distribute evenly, and refine the grain size of the magnet. Ho can improve the intrinsic coercivity, Gd can enhance the Square degrees of the demagnetization curve of the J-H well, but the remanence and magnetic energy product will be lower. Moreover, Gd and Ho reduces magnets open flux irreversible loss, and makes magnets with better thermalstability.