| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a bilayer film formation method yielding an excellent finish and corrosion resistance without affecting electrodeposition coatability even if a water washing process following a chemical treatment is partially or entirely dispensed with; and a coated object.SOLUTION: The provided bilayer film formation method is a bilayer film formation method including the following processes for forming a chemical treatment film and an electrodeposition coating film atop a metal-coated object: process 1: a process for forming a chemical treatment film on a metal-coated object by immersing the object within a chemical treatment liquid; and process 2: a process for forming an electrodeposition coating film by electrodeposition-coating the metal-coated object by using a cationic electrodeposition coating material while partially or entirely dispensing with a water washing process wherein the sodium ion content of the chemical treatment liquid by the mass standard is below 500 ppm.</p> |
