METHOD OF TREATING SURFACE OF METAL BASE, METALLIC MATERIAL TREATED BY THE SURFACE TREATMENT METHOD, AND METHOD OF COATING THE METALLIC MATERIAL

摘要

A method of treating the surface of a metal base which is conducted prior to cationic electrodeposition coating in order to improve throwing power in the cationic electrodeposition coating; a metallic material treated by the surface treatment method; and a method of coating this metallic material. The method of treating the metal surface of a metal base, which improves throwing power in cationic electrodeposition coating, comprises: a surface treatment step in which a metal surface treatment composition comprising zirconium ions and/or titanium ions and an adhesion promoter characterized by being at least one member selected from the group consisting of (A) silicon compounds, (B) adhesion-promoting metal ions, and (C) adhesion-promoting resins is brought into contact with a metal base to form a chemical conversion coating on the base; and a heat-drying step in which the metal base having the chemical conversion coating formed is heated at 60-190° for 30 seconds or longer to dry the coating.