IRON POWDER FOR HIGH PERMEABILITY GREEN COMPACT MAGNETIC CORE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To obtain a high magnetic permeability without bringing a cost increase on deterioration of moldability upon an iron powder by specifying the strain quantity evaluated by the half-value width of anαFe (200) peak by X-ray diffraction to a specific value or below and the average crystal grains size to a specified value or above. SOLUTION: The strain quantity of the iron powder evaluated by the half- value width of theαFe (200) peak by the X-ray diffraction is <=0.18 deg and the average crystal grains size is >=10μm. The sponge iron of >=0.35 deg of the strain quantity evaluated by the half-value width of theαFe (200) peak by the X-ray diffraction is adequately used as feed sponge iron in order to efficiently produce such iron powder. The energy introduced by the pulverization of such feed sponge iron acts as driving force for restoration and recrystallization at the time of finish reduction, thereby decreasing the strain quantity of the product iron powder and growing the crystal grains. The pulverizing machine used for pulverization includes an ordinary ball mill, etc. The finish reduction annealing is preferably executed under conditions of 800 to 950 deg.C and 20 to 120 minutes.