Soft magnetic material and method for producing the same

Abstract

Disclosed are a soft magnetic material having an optimum electrical resistivity and a method for producing such a soft magnetic material. The soft magnetic material comprises a plurality of composite magnetic particles. Each of the composite magnetic particles comprises a metal magnetic particle and an insulating coating film which covers the surface of the metal magnetic particle and contains at least one substance selected from the group consisting of zirconium oxide, aluminum oxide and silicon oxide. The soft magnetic material has an electrical resistivity of not less than 3,000 μΩcm and not more than 50,000 μΩcm, and a magnetic permeability μ of not less than 2,000 and not more than 4,000. A method for producing such a soft magnetic material comprises a step for pressure forming a compaction by compressing a plurality of the composite magnetic particles and a step for subjecting the compaction to a first heat treatment at not less than 400° C. and not more than 900° C.

1 . A soft magnetic material comprising a plurality of composite magnetic particles, wherein 
 each of said plurality of composite magnetic particles has a metal magnetic particle and an insulating coating film, containing at least one substance selected from a group consisting of aluminum oxide, zirconium oxide and silicon oxide, surrounding the surface of said metal magnetic particle, and    electric resistivity ρ is at least 3000 μΩcm and not more than 50000 μΩcm and magnetic permeability μ is at least 2000 and not more than 4000.    
     
     
         2 . (canceled)  
     
     
         3 . A method for producing the soft magnetic material according to  claim 1 , comprising the steps of: 
 preparing a compaction by pressing a plurality of composite magnetic particles having metal magnetic particles and insulating coating films, containing at least one substance selected from a group consisting of aluminum oxide, zirconium oxide and silicon oxide, surrounding the surfaces of said metal magnetic particles; and    performing first heat treatment on said compaction under the atmospheric pressure at a temperature of at least 400° C. and not more than 900° C.    
     
     
         4 . The method for producing a soft magnetic material according to  claim 3 , further comprising the step of pressing said compaction after performing said first heat treatment and thereafter performing second heat treatment under the atmospheric pressure at a temperature of at least 400° C. and not more than 900° C.