METHOD FOR PRODUCING METAL POWDER FOR DUST CORE AND METHOD FOR MANUFACTURING DUST CORE

摘要

A pure iron powder of a diameter of 10 to 500 μm and a purity of 99% by mass or more is heated to a temperature in the range of 600 to 1400° C., and a Si-concentrated layer is formed in regions within a depth of 5 μm from the surfaces of the powder particles by gas-phase reaction at a temperature of that range. The average Si concentration in the regions within this depth is controlled in the range of 0.05% to 2% by mass. Thus, a dust core metal powder enhancing the adhesion of insulating material to the particle without degrading compressibility is produced. The resulting dust core maintains a high saturation magnetic flux density and exhibits a low iron loss.