Dust core with specific relationship between particle diameter and coating thickness, and method for producing same

Abstract

The object of the present invention is to provide a powder core and method for making the same that is equipped with insulative coating having superior heat resistance, with the coating making it possible to adequately restrict the flow of eddy currents between particles. The powder core is equipped with a plurality of compound magnetic particles bonded to each other. Each of said plurality of composite magnetic particles includes: a metal magnetic particle 10; an insulative lower layer coating 20 surrounding a surface 10a of said metal magnetic particle 10; an upper layer coating 30 surrounding said lower layer coating 20 and containing silicon; and dispersed particles 50 containing a metal oxide compound and disposed in said lower layer coating 20 and/or said upper layer coating 30. A mean particle diameter R of the dispersed particles 50 meets the condition 10 nm<R≦2 T, where the average thickness of the coating combining the lower layer coating 20 and the upper layer coating 30 is T.

Dependencies are inferred from the claim text.