PRODUCTION OF METAL MAGNETIC POWDER DUST CORE MATERIAL

摘要

PROBLEM TO BE SOLVED: To obtain a core material exhibiting excellent characteristics in both of saturated magnetic flux density and high-frequency property by heating a gas-atomized metal based soft magnetic powder in an oxidizing gas atmosphere at a specific temp. to oxidize the surface, mixing a specific quantity of a glass based material and extruding the mixture at a high temp. SOLUTION: The metal based soft magnetic powder of an Fe-Si based alloy obtained preferably by an atomizing method and having <=1000μm particle diameter is heated in an oxygen gas-containing atmosphere at a high temp. of >=900 deg.C to oxidize the surface to form an oxide film having insulating property on the powder surface. The glass based material such as a lead glass softened at a high temp. and made plastic is mixed by 1-6% to the weight of the metallic powder in the oxidation treated powder. The powdery mixture is filled in a metal-made capsule and worked by high temp. extrusion at 600 deg.C in the extrusion ratio of >=2. As a result, the dust core material improved in magnetic flux density by making the metallic powder highly dense with high packing factor and improved in high frequency property by suppressing the electrical conductivity of the contact part of powders with each other by the insulating oxide film is obtained.