| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for treating a surface with a hexavalent chrome free treatment liquid, which allows manufacturing a heavy anticorrosion organic coated steel material excellent in anticorrosiveness, adhesion, cathode peeling resistance, and thermal cycle durability.SOLUTION: An aqueous solution containing a zirconium compound, a vanadium compound, ammonium phosphate, and a silane coupling agent as essential components and having pH of 8 or more and 12 or less, is applied to a surface of a steel material to form a ground layer having a coating weight equal to or more than 50 mg/mand less than 1500 mg/min metal Zr conversion. The ground layer is coated by one or more organic resin layers for anticorrosion coating. |
