Substituted chromic acid passivation environmental protection process

Abstract

The invention provides a substituted chromic acid passivation environmental protection process. A passivation solution for passivation comprises 10-20 g / L of ammonium persulfate, 2-6 g / L of phytic acid, 15-25 g / L of trisodium phosphate, 1-3 mL / L of phosphoric acid, 0.5-1 mL / L of boric acid, 0.5-3 g / L of zirconium n-propoxide, 0.1-1 g / L of benzotriazole, 3-6 g / L of complexing agent, 5-10 g / L of water-soluble film-forming resin, 4-6 g / L of nanometer silica, 0.1-3 g / L of stabilizing agent, and the balance water. The passivation solution completely meets the electroplating wastewater discharge standards of China, RoHS of the European Union and other environmental protection standards. According to the process, ammonium persulfate and trisodium phosphate serve as main passivation substances, phytic acid serves as an auxiliary passivation substance, and the chelation bridging effect is achieved through crosslinking of water-soluble film-forming resin and the complexing agent, so that a three-substance combined molecular composite film layer is formed. Accordingly, the film forming effect is good, the film forming speed is high, and the film layer has good adhesive force and is compact and uniform in film formation.

Description

technical field

[0001] The invention belongs to the technical field of metal surface treatment, and in particular relates to an environmentally friendly process replacing chromic acid passivation. Background technique

[0002] Hot-dip metal materials, including hot-dip galvanized metal materials and hot-dip galvanized metal materials, in order to prevent corrosion, a layer of metal protective paint will be coated on the surface of the hot-dip metal materials to form a protective film. Therefore, the performance of metal protective coatings is very important for the anti-corrosion of hot-dip metal materials.

[0003] Hexavalent chromate passivation technology is a chemical conversion surface treatment technology commonly used in industry due to its excellent corrosion resistance and good self-healing ability of chemical conversion film. However, due to the high toxicity of hexavalent chromium, it not only produces serious waste water and waste residue pollution in the prod...

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