Solution and process for combined phosphatization

摘要

Combined phosphatization acid solution suitable for producing on a metallic substrate a concomitent deposit of at least two metallic ions, of which at least one is generally selected from the group comprising zinc, manganese and iron, said solution being characterized by the fact that it contains a polyphosphate having the formula (XPO3)n wherein n>/=3 and X represents an alkaline, alkaline-earth metal or ammonium, and a chelating agent.