MAGNETIC POWDER FOR MAGNETIC RECORDING MEDIUM

摘要

A magnetic powder for a magnetic recording medium is obtained by forming a silica layer on a surface of an acicular iron oxide fine powder as a core by treating it with a silicon compound before preparing a cobalt modified acicular iron oxide fine powder by dispersing said acicular iron oxide fine powder as the core in an aqueous solution of ammonia containing cobalt ion and treating it in an inert gas atmosphere at high temperature or in a reduction atmosphere.