| 摘要 |
PURPOSE:To contrive improvement in corrosion-resisting property by a method wherein a film, consisting of Fe3O4, gamma-Fe2O3 or the mixture o them, is formed on the surface of the magnetic metal powder which is mainly composed of iron. CONSTITUTION:A high density film having excellent oxidation-resisting property, consisting of at least one or more kinds of ferrous oxide selected from [Fe3O4], [gamma-Fe2O3] and [mixture of Fe3O4 and gamma-Fe2O3] of the cubic volume of 5-50% for the cubic volume of magnetic metal powder, is formed on the grain surface of the magnetic metal powder which is mainly composed of iron by placing said magnetic metal powder in the mixture of oxygen gas and nitrogen gas at 80-110 deg.C for 1-100hr after the magnetic metal powder is placed in the mixture of oxygen gas and nitrogen gas at the temperature of 40-70 deg.C for 1-10hr. As a result, the corrosion-resisting property of the magnetic metal powder mainly composed of iron can be improved substantially. |
