METHOD FOR MANUFACTURING DUST CORE AND DUST CORE OBTAINED BY THE METHOD

摘要

TO PROVIDE A METHOD FOR MANUFACTURING A DUST CORE AND A DUST CORE CAPABLE OF IMPROVING THE STRENGTH WITHOUT GREATLY LOWERING THE DENSITY. THE METHOD FOR MANUFACTURING A DUST CORE INCLUDES A MOLDING STEP OF OBTAINING A POWDER COMPACT BY COMPRESSION-MOLDING A MIXTURE OF IRON-BASED SOFT MAGNETIC POWDER FOR POWDER COMPACT AND A LUBRICANT, THE IRON-BASED SOFT MAGNETIC POWDER FOR POWDER COMPACT INCLUDING A PHOSPHORIC ACID-BASED CHEMICAL CONVERSION COATING ON THE SURFACE OF THE IRON-BASED SOFT MAGNETIC POWDER, A HEAT TREATMENT STEP 1 OF HEATING THE POWDER COMPACT AT 300°C OR ABOVE AND 500°C OR BELOW, A HEAT TREATMENT STEP 2 OF EXECUTING HEATING THEREAFTER AT ABOVE 500°C AND 700°C OR BELOW IN AN OXIDATIVE ATMOSPHERE, AND A HEAT TREATMENT STEP 3 OF EXECUTING HEATING FOR 30 MIN OR MORE AND 120 MIN OR LESS AT 300°C OR ABOVE AND 450°C OR BELOW.