Means for optimized passivation on Ti / Zr-based metal surface, and methods for conversion treatment

An aqueous chromium-free agent for the corrosion protective conversion treatment of metallic surfaces, comprising (A) one or more water-soluble compounds containing at least one atom selected from the elements titanium and / or zirconium, the total concentration of these elements 2.5 x 10 mol / l is not less than, but not greater than 2.0 × 10 (B) one or more water-soluble compounds as a source of fluoride ion comprising at least one fluorine atom, wherein the means designated elements of the respective components (A) and (B) in a molar ratio A: contains z, where z is a real number and greater than 6: B of 1 characterized in that additionally in the middle (C) one or more water-soluble compounds which release copper ions containing at least a copper atom, and (D) one or more water-soluble and / or water-dispersible compounds, which release metal ions include, but are not a source of fluoride ions, comprising at least one metal atom selected from the group consisting of calcium, magnesium, aluminum, boron, iron, manganese and / or ...