FERROMAGNETIC POWDER FOR MAGNETIC RECORDING MEDIUM AND METHOD FOR PREPARATION THEREOF

摘要

A ferromagnetic powder which contains at least Fe-B or Fe-Co-B with the surface of the powder having thereon a layer of Cr of a layer mainly consisting of Cr and a method of preparing the ferromagnetic powder comprising reducing a metal salt capable of forming a ferromagnetic powder containing at least Fe or Fe-Co in an aqueous solution thereof with one or more borohydride compounds or derivatives thereof and after the reduction is initiated adding an aqueous solution containing Cr ion or an anion containing Cr.