| 摘要 |
PROBLEM TO BE SOLVED: To provide an electromagnetic steel sheet with an insulating coating film, which comprises mainly a Cr-free inorganic substance, and has excellent corrosion resistance after baking at≤300°C (before stress relieving annealing) and corrosion resistance after stress relieving annealing. SOLUTION: The electromagnetic steel sheet with an insulating coating film comprises Zr, P and one or more selected from Mg and Ca, and in which the molar ratio of P to Zr, P/Zr, is 0,4 to 4.0, and the molar ratio of the total of Mg and Ca to Zr, (Mg+Ca)/Zr, is 0.005 to 0.10. For example, the insulating coating film is obtained by coating the surface of an electromagnetic steel sheet with a coating material, as raw materials, comprising ammonium zirconium carbonate as a Zr compound, magnesium phosphate as a P compound, magnesium hydroxide as an Mg compound and calcium hydroxide as a Ca compound, and baking the same, so as to be a film. Further, a resin may be incorporated into the insulating coating film. COPYRIGHT: (C)2008,JPO&INPIT |
