METALLIC POWDER FOR POWDER MAGNETIC CORE AND PROCESS FOR PRODUCING POWDER MAGNETIC CORE

摘要

A pure iron powder having a diameter of 10 to 500 µm and a purity of not less than 99% by mass is heated to a temperature region of 600°C or above and 1400°C or below. In this temperature region, Si is enriched in a depth range of 5 µm from the surface of the pure iron powder by a gas phase reaction, and the average Si concentration in this depth range is brought to not less than 0.05% by mass and not more than 2% by mass. According to the above constitution, a metallic powder for a powder magnetic core, which has an enhanced bond strength between an insulating material and particles and in its turn has enhanced electrically insulating properties, can be provided without leading a deterioration in compressibility. In the powder magnetic core thus obtained, a high level of saturated magnetic flux density can be maintained, and a low level of iron loss can be realized.