| 摘要 |
PROBLEM TO BE SOLVED: To provide a chromium-free chemical conversion treatment liquid that may provide excellent corrosion resistance and paint adhesion on a surface of metallic materials such as aluminum and aluminum alloy represented by an aluminum die casting material and the like.SOLUTION: The problem is solved by providing a chromium-free chemical conversion treatment liquid comprising a titanium fluoride complex ion having a concentration of 2 to 400 ppm in terms of Ti, and pentavalent vanadium compound ion having a concentration of 10 to 1000 ppm in terms of V and having a pH in the range of 2.4 to 4.4. The weight ratio (A/B) of the concentration A of the titanium fluoride complex ion in terms of Ti and the concentration B of the pentavalent vanadium compound ion in terms of V is preferably in the range of 0.1 to 4.5, and the chromium-free chemical conversion treatment liquid preferably further comprises a zirconium fluoride complex ion having a concentration of 1 to 1000 ppm in terms of Zr. |
