Patent ID: 8337638

Claim:
A method for producing a powder for a dust core, comprising performing silicon impregnation of the surface of a soft magnetic metal powder containing a carbon element, wherein: silicon impregnation is performed by bringing a powder for silicon impregnation containing at least a silicon compound into contact with the surface of a soft magnetic metal powder comprising an iron-based powder, heating the powder for silicon impregnation to dissociate a silicon element from the silicon compound, and then diffusing the thus dissociated silicon element throughout the surface layer of the soft magnetic metal powder via impregnation; silicon impregnation is performed under a diffusion atmosphere allowing dissociation where the reaction rate at which the silicon element is dissociated is higher than the diffusion rate at which the silicon element is diffused throughout the surface layer of the soft magnetic metal powder via impregnation; and the diffusion atmosphere allowing dissociation is formed by adjusting the carbon element content in the soft magnetic metal powder to range from 0.1% by weight to 1.0% by weight, adjusting the silicon element content (% by weight) in a silicon compound to be at least the same as or higher than the carbon element content, and adjusting the temperature for heat treatment to range from 900° C. to 1050° C.