| 摘要 |
PROBLEM TO BE SOLVED: To increase the adhesion of coating, to impart strong tension to a steel sheet and to improve the effect of improving iron loss by applying metallic plating to the magnetically smoothened surface of a steel sheet, furthermore subjecting the plated face to electrolytic etching and thereafter forming tension- applied type coating. SOLUTION: As for the metallic plating, one or two kinds among the simple substances and alloys Ni, Co, Fe, Cu and Cr are used, an a plating layer having 0.1 to 5 μm thickness is formed. After that, it is subjected to electrolytic etching, and 1/10 to 2/3 of the plating layer thickness is eluted to make the plated face porous, and coating of phosphate-colloidal silica-chromic acid or the like is applied thereto. Furthermore, it is simple and rational that the electrolytic etching is executed in such a manner that, in succession to the metallic plating in an electrolytic plating bath, the polarity is reversed. Since the plated metal subjected to the etching is reduced into the plating bath as it is, it can again be reutilized for the plating of a steel sheet. |
