| 摘要 |
PURPOSE:To improve the magnetic characteristic of an amorphous magnetic steel strip by subjecting said strip to a surface treatment including a phosphate treatment and/or chromate treatment to stick an insulating film thereon then annealing the strip in an oxidative atmosphere. CONSTITUTION:The amorphous magnetic steel strip is subjected to the surface treatment in an aq. soln. consisting essentially of phosphoric acid and water soluble metallic salt and/or an aq. soln. consisting essentially of chromic anhydride and chromate. The insulating film consisting of the mixed film composed of the phosphate film and chromate film is thereby stuck onto said strip at a ratio of 10-1,000mg/cm<2> in terms of dry film weight. Methods such as roll coating and treating method and electrolytic treating method are adequately used for the surface treating method. The thickness of the above-mentioned film is 30- 5,000Angstrom . The above-mentioned steel strip stuck with the film is annealed in the oxidative atmosphere, for example, an atmosphere of air or a gaseous mixture composed of air and inert gas by which the insulating film having necessary interlayer resistance is obtd. without spoiling the max. effect in the magnetic characteristics, i.e., a small iron loss. |
