R-FE-B TYPE PERMANENT MAGNET SUPERIOR IN ELECTRIC INSULATION, HEAT RESISTANCE AND CORROSION RESISTANCE AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide an R-Fe-B type permanent magnet superior in electric insulation, heat resistance and corrosion resistance by covering a specified Al or Zn surface metal layer of specified thickness on the surface of this magnet with a polyimide resin through a chromate-treated film by the vacuum evaporation polymerization. SOLUTION: An Al or Zn first metal film of 1.0-10.0μm thick is formed on the surface of an R-Fe-B type permanent magnet having a tetragonal main phase and polyimide film of 2.0-10μm thick is formed on this metal film to form a magnet superior in electric insulation, heat resistance and corrosion resistance. The manufacturing method thereof comprises cleaning the surface of this magnet having the tetragonal main phase, forming the Al or Zn metal film of 1.0-10.0μm on the surface of the magnet by the plating or vapor phase forming method, treating the metal film with chromate, and forming a polyimide film layer of 2.0-10μm thick in vacuum by the evaporation polymerization.