To provide a non-chromium insulating film having necessary performances, excellent stability and excellent peeling resistance after annealing even with a thin film of ≤0.5 μm by applying treatment solution with phosphate being a film-forming component on a surface of an electric steel sheet, and by the baking at low temperature.
An insulating film is formed out of treatment solution containing first phosphate (A) to be selected among first phosphate of Al, Mg, Ca, Sr, Ba and Zn, chelating agent (B) consisting of phosphorate compound or phosphorate compound and carboxylic compound, and polyamine (C). The ratio of the total sum ΣMi of the product of the valency×molar number of multivalent metal cations to the molar number ΣPi of phosphor in the treatment solution satisfies the inequalities (1): 1.5≤ΣMi/ΣPi≤5, and the ratio of the total sum ΣOi of the product of the molar number of the chelating agent (B) of the number of acid groups in the molecule to the ΣMi satisfies the inequalities (2): 0.1≤ΣOi/ΣMi≤5.
TAKAMARU HIROKI
NAKAGISHI TETSUYUKI
KITAYAMA HIROAKI
ASAHI KAGAKU KOGYO CO LTD
| JP2001107261A | 2001-04-17 | |||
| JP2008303411A | 2008-12-18 | |||
| JP2005126739A | 2005-05-19 | |||
| JPS6214405A | 1987-01-23 | |||
| JP2003034880A | 2003-02-07 | |||
| JP2002180134A | 2002-06-26 |
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