ELECTROLYTIC PHOSPHATING PROCESS AND COMPOSITE COATING FORMED ON STEEL SURFACE

摘要

The present invention provides a phosphate chemical treatment technology suitable for electrolytic treatment. The present invention discloses a phosphate chemical treatment bath containing at least phosphate ions and phosphoric acid, nitrate ions, metal ions that form a complex with phosphate ions in the phosphate chemical treatment bath, and metal ions for which the electrical potential, at which the ions of the metal dissolved in the phosphate chemical treatment bath are reduced and precipitate as metal, is equal to or greater than the anodic electrolytic reaction potential of water as the solvent; the concentration of metal ions other than those which are a component of the film in the treatment bath being 0-400 ppm, and the treatment bath being substantially free of solids that have an effect on the film formation reaction. IMAGE