A preparation method of
neodymium iron
boron magnet is disclosed. The composition general formula of the
magnet provided by the invention is R1R2FeMB, wherein R1 is at least one element selected from the group consisting of Nd, Pr, La, Ce, Sm, Sc, Y and Eu, having a content of 23 to 35 wt%; R2 is at least one element selected from the group consisting of Tb, Dy, Gd, and Ho, having a content of 0.1 to 5 wt%; M represents transition group
metal with the exception of Fe, having the content of 0.01 to 5 wt%; B represents simple substance
boron, having the content of 0.8 to 1.2 wt%; the balance isFe and the other inevitable impurities. The preparation method of
neodymium iron
boron magnet provided by the invention works in such a manner that: one or more elements in the R2 are plated to the surface of the magnet, the
metal R2 is diffused into the interior of the magnet by primary high temperature heat treatment, and imbalance organization and
internal stress brought by the high
temperature treatment are eliminated through secondary low temperature
tempering. Low temperature
molten salt electrodeposition method is employed to plate films. The present invention is advantageous in greatly improving the production efficiency, reducing the dosage of the heavy
rare earth during preparation process of magnet, saving
rare earth resource, and obtaining high
coercivity without reducing remanent
magnetism and
magnetic energy product of a magnet.