| 摘要 |
The paint adhesion and corrosion resistance of surfaces of aluminum and its alloys, particularly when using a paint based on poly(vinyl chloride), is improved by using a conversion coating solution having a pH in the range from 1.0 to 3.0 and containing: (A) an amount of phosphate ions that is stoichiometrically equivalent to at least 5.0 g/L of phosphoric acid; (B) at least 1.0 g/L of hexavalent chromium; (C) at least 0.1 g/L of fluoride ions; and (D) a complex fluoride ion component selected from the group consisting of: (i) at least 4.0 g/L of fluosilicate ions, (ii) at least 0.5 g/L of fluoborate ions, (iii) at least 2.0 g/L of fluozirconate ions, and (iv) at least 2.0 g/L of fluotitanate ions. |
