MANUFACTURE OF CORE

PURPOSE:To reduce iron loss in a high frequency region by forming a high molecular layer by polymerizing a monomer attached onto the surfaces of magnetic powder and compression-molding magnetic powder. CONSTITUTION:A solution in which a monomer is dissolved in a solvent easy to be evaporated and removed is manufactured, and magnetic powder is introduced into the solution and suspended. Pure iron powder, Fe-Si alloy powder, Fe-Al alloy powder, etc. are used as magnetic powder, and an acrylic group, a styrene group, an ethylene group, etc. employed as the monomer. The monomer as one part is adsorbed onto the surfaces of magnetic powder in the solution. The solvent is removed, and the monomer on the surfaces of magnetic powder are polymerized through a proper method. Lastly, a mold for molding is filled with magnetic powder, the surfaces thereof are coated with a high molecular layer, and magnetic powder is compression-molded, thus obtaining a core. Accordingly, since electrical insulating properties among magnetic powder particles are improved, eddy current loss to AC magnetization of the whole core is reduced extremely, and iron loss is also minimized.