| 摘要 |
PROBLEM TO BE SOLVED: To provide a non-chromium rust preventing treatment excellent in rust preventing property and adhesion property with overcoating films and to provide a galvanized steel sheet treated with a rust preventive. SOLUTION: In the rust preventing treatment of metal, a galvanized steel sheet is brought into contact with an aq. soln. containing one or more kinds of ions of phosphoric acid compds. selected from phosphate ion, condensed phosphate ion, phytate ion and phosphonate ion by 0.1 to 200 g/l concn. After the sheet is washed with water, a rust preventive coating agent containing one or more kinds of sulfur compds., selected from sulfides, sulfur powder, triazine thiol compds., thiocarbonyl group-contg. compds. and sulfur oxides by 0.1 to 20 g/l and containing a water-based resin and further water-dispersible silica by 10 to 500 g/l concn. is applied on the sheet. The galvanized steel sheet subjected to rust preventing treatment is obtd. by treating a steel sheet by the method above described.
|
