Process adapted to provide on a metallic substrate a protective coating based on hexavalent chromium, bath used in the said process and commercial form of the components of the bath

摘要

Process comprisingPPa step for the preparation of the metallic substrate by degreasing, possibly followed by mechanical or chemical pickling,PPa step comprising the use by immersion or spraying of a bath adapted to provide on the metallic substrate the contemplated protective coating andPPa curing step at high temperature,PPand characterized by the fact that the above-mentioned bath comprises at least:P Pa metal in the form of particles,PPchromic acid and/or one of its derivatives as oxidizing agent,PPat least one hydrosoluble solvent having a high boiling point and selected from those of the aprotic polar type and of the ketonic type,P Pwater.