PURPOSE: To manufacture a sintered permanent magnet made of Nd-Fe-B or Nd-Fe-Co-B alloy having high performance only by inner lubricant without mold lubrication by a powder metallurgy method while continuously press mold ing.
CONSTITUTION: A sintered permanent magnet is manufactured by press molding and sintering the mixture of 100 pts.wt. of alloy powder having a mean particle size of 1 to 20μm and mean crystalline grain size of 1 to 30μm of alloy composition obtained by heat-treating a spheroidal powder having a mean particle size of 500μm or less obtained by a gas atomization method in vacuum or in inert gas atmosphere at 1000°C or lower in some cases, and then comminuting it, and 0.01 to 2 pts.wt. of boric acid ester compound as inner lubricant. Thus, the magnet which can be continuously pressed without mold lubrication and has excellent magnet characteristics of high (BH)max can be manufactured with high productivity.
HIRAISHI NOBUSHIGE
KISHIMOTO YOSHIHISA
ISHIGAKI NAOYUKI
SUMITOMO SPEC METALS