| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for preparing a R-Fe-B based sintered magnet which enables the achievement of a high processing speed, uniform coating, a high production efficiency, and enables the large increase in the coercive force of the magnet after heat treatment because terbium(Tb) and dysprosium(Dy) are sprayed to a surface of a sintered magnet by a thermospray method.SOLUTION: The present invention relates to a method for preparing an R-Fe-b based sintered magnet. The method comprises the steps of: first, preparing an R-Fe-b based sintered magnet having a thickness 1-10 mm by a typical method; then, spraying, by a thermospray method, metallic Tb or Dy to the surface of the sintered magnet in a sealed box until a thickness of 10-200 μm is reached, provided that the inside of the sealed box is placed in an argon gas protection atmosphere; and at the end, setting the sintered magnet with its surface sprayed with Tb or Dy in a vacuum sintering furnace and then, performing a thermal treatment on the sintered magnet at a temperature of 750-1000°C under vacuum or argon gas protection atmosphere so that the heavy rare earth element Tb or Dy is diffused into the sintered magnet along grain boundaries. |
