Patent ID: 7235208
Filing Date: 2007-06-26
Classification: H01F,Y10T

Abstract:
1. A method of producing a dust core comprising mixing a ferromagnetic powder with an insulating material, drying the resulting mixture, pulverizing the dried mixture, combining a lubricant with the dried, pulverized mixture, pressure molding the resulting combination to form a molded core; and heat treating the molded core at a temperature in the range of about 300 to about 800° C. for a time period in the range of about 20 minutes to about 2 hours in a non-oxidizing atmosphere; the insulating material comprising a trifunctional methyl-phenyl silicone resin having a phenyl content in the range of about 15 mol % to about 60 mol %, based on all organic groups in the silicone resin, wherein the methyl-phenyl silicone resin comprises about 20 mol % to about 70 mol % of trifunctional silicone structural units, based on total moles of methyl-phenyl silicone resin, and the amount of methyl-phenyl silicone resin in the dust core being in the range of about 0.5 to about 3% by weight, based on the weight of ferromagnetic powder.