Method of producing galvanized steel sheets Molly phosphate coating treatment solution and the improvement of corrosion resistance after resin coating by using this, galvanized steel

摘要

PURPOSE: A liquid for treating a molyphosphate film and a method of fabricating a galvanized steel sheet are provided to be improved in corrosion resistance of the liquid after coating resin by improving combining force between a molyphosphate film and the resin layer and to fabricate a galvanized steel sheet excellent in corrosion resistance with the liquid. CONSTITUTION: A liquid for a molyphosphate film is prepared by adding 8.0-50g/l of nitric acid and over 2g/l of gamma-glycidoxypropyltrimethoxysilane to 4.0-30g/l of molybdenum and 7.0-14g/l of phosphoric acid. A molyphosphate film is formed by depositing a galvanized steel sheet in the liquid. The galvanized steel sheet improved in corrosion resistance is manufactured by coating acrylic resin on the molyphosphate film about 1000-1200mg/m2.