POWDER MAGNETIC CORE, METHOD FOR MANUFACTURING POWDER COMPACT FOR MAGNETIC CORE, PRESSING DIE AND MOLD DEVICE FOR MANUFACTURING POWDER MAGNETIC CORE, AND LUBRICANT COMPOSITION FOR PRESSING DIE FOR MANUFACTURING POWDER MAGNETIC CORE

摘要

A powder compact for a magnetic core, said powder compact being manufactured by filling the die hole of a die with a soft magnetic powder and compressing the soft magnetic powder to a density ratio of 91% or higher, thereby forming the powder compact, which is then extruded from the die hole. Before the die hole is filled with the soft magnetic powder a lubricant coating film containing a lubricating oil and molybdenum disulfide particles is formed on the inner surfaces of the die hole. A lubricant coating film containing insulating ceramic particles also is effective. The extruded sliding surface of the powder compact has a surface layer part wherein the molybdenum disulfide particles and the insulating ceramic particles are interposed between the particles of the soft magnetic powder, and the powder magnetic core is configured using this powder compact. When the powder compact is extruded from the die hole the insulated state of the soft magnetic powder particles in the surface layer part is not destroyed, so a powder magnetic core suitable for high-frequency applications can be provided.