| abstract |
[PROBLEMS] To prevent a decrease in film tension and moisture absorption resistance, which becomes a problem when an insulating film treatment solution is made chrome-free, and to provide characteristics necessary for an insulating film of grain-oriented electrical steel sheets, that is, film tension, moisture absorption resistance, and prevention. We propose a chromium-free insulating coating solution for grain-oriented electrical steel sheets that has a rust property and a space factor comparable to those obtained when an insulating coating solution containing a chromium compound is used. SOLUTION: One or more selected from Mg, Ca, Ba, Sr, Zn, Al, and Mn phosphates are contained, and PO 4 in the selected phosphates is used as a reference. In addition, 0.5 to 10 mol of colloidal silica in terms of SiO 2 and 0.1 to 2.0 mol of water-soluble vanadium compound in terms of V are added to 1 mol of PO 4 . [Selection] Figure 1 |