Method for grain boundary adulterated by oxide or nitride to improve the NdFeB permanent magnetic material performance

Abstract

The invention relates to a method of a rare earth material technic field for adding an oxide in a grain boundary or increasing an Nd-Fe-B permanent magnetic material performance by a nitride, the method comprises: (1) preparing an Nd-Fe-B ingot casting alloy by an ingot casting process or preparing an Nd-Fe-B alloy rapid hardening thin sheet by a rapid hardening thin sheet process, (2) performing rough-cracking on the alloy and grinding the alloy to powder by an air flow; (3) adding oxide or nitride powder and evenly mixing; (4) directional press-forming the mixed power in a magnetic field, isostatic cool pressing a blank after being directional press-forming; (5) putting the blank into a high vacuum fritting furnace, producing a magnet by fritting and tempering. The Nd-Fe-B permanent magnetic material has a chemical formula of NdaFe100-a-b-cBbMc, atom percents are: 12<=a<=24, 5.5<=b<=7, 0<=c<=7; M is one or more of elements Dy, Tb, Co, Ga, Al, Cu. The fritted Nd-Fe-B prepared in the invention has better magnetic performance and corrosion resistance than the magnet produced without adding the oxide or the nitride.

Description

technical field

[0001] The invention relates to a method in the technical field of rare earth materials, in particular to a method for improving the magnetic properties, thermal stability and corrosion resistance of NdFeB permanent magnet materials by adding oxides or nitrides at grain boundaries to improve NdFeB permanent magnets. approach to material properties. Background technique

[0002] Sintered NdFeB magnets have high remanence, coercive force and maximum magnetic energy product. Since their inception, they have been widely used in many fields such as national defense, household appliances, medical machinery, electronic information and automobile industries, especially in recent years. The popularity of computers, electronic communications and other equipment and the rapid development of low-energy automotive motors have broadened its application prospects. However, the low thermal stability and corrosion resistance of NdFeB permanent magnet materials greatly reduce...