R-FE-B PERMANENT MAGNET EXCELLENT IN ELECTRIC INSULATION, HEAT RESISTANCE, AND CORROSION RESISTANCE, AND ITS MANUFACTURE

摘要

PURPOSE: To enhance the electric insulation, heat resistance, and corrosion resistance by covering the surface of an R-Fe-B permanent magnet with a polyimide resin layer through a carbon layer with a specified thickness by vapor polymerization method. CONSTITUTION: This is an R-Fe-B permanent magnet which has a polyimide layer 2.0μm-10μm thick on the surface of its main body whose main phase consists of tetragonal crystal through a carbon layer 0.005μm-0.1μm thick. And, for the manufacture, a polyimide layer 2.0μm-10μm thick is made by vapor polymerization after formation of carbon layer 0.005μm-0.1μm thick on the surface of a magnet by the PVD film formation method of vapor deposition, sputtering, and ion plating, after cleaning the surface of the R-Fe-B permanent magnet. The vapor polymerization is one which imide processing is performed at 280 deg.C-380 deg.C under normal pressure after formation of a polyamic acid film by heating and deposing two kinds of monomers at 200 deg.C-250 deg.C in a vacuum enclosure where the pressure is 1-10<-3> Pa.