| 摘要 |
PROBLEM TO BE SOLVED: To form an insulating film for a grain oriented silicon steel sheet, in which the instability of iron loss value is improved and the necessity of restrictions on the average grain size required of a compound hydroxide is obviated, by mixing a compound hydroxide and one or more kinds among boric acids, silicic acids, phosphoric acids, and salts thereof in specific ratio and subjecting the resultant solution mixture to treatment for improving dispersibility and compatibility. SOLUTION: The compound hydroxide is represented by general formula M<2+> 1-x M<3+> x (OH<-> )2+x-ny (A<n-> )y .mH2 O. In the formula, M<2+> is a divalent metal ion such as Be<2+> , M<3+> is a trivalent metal ion such as Al<3+> , A<n-1> is an n-valent anion such as OH<-> , (x) satisfies 0<x<1, and (m) is the number of molecules of interlamellar water. One or >=2 kinds among boric acids, silicic acids, phosphoric acids, and salts thereof are mixed by 0.5 to >10.0 pts.wt. with 1 pts.wt. of the above compound hydroxide. Then, treatment for improving dispersibility and compatibility is applied to the resultant solution mixture by the use of a propeller blade type agitator, etc., to refine the compound hydroxide, etc. |
