摘要 |
A metal surface treatment method for a metal base material in order to improve the uniformity of a cathodic electrodeposition coating film, the method including: a surface treatment step for forming a chemical conversion film on a metal base material by contacting the metal base material with a metal surface treatment composition including zirconium and/or titanium ions and an adhesive imparting agent characterized in being at least one selected from the group consisting of (A) silicon-containing compound, (B) adhesive imparting metal ion, and (C) adhesive imparting resin; and a heating/drying step to heat and dry the metal base material, on which the chemical conversion film is formed, at 60° C. to 190° C. for at least 30 seconds. |