PROCESS FOR PREPARING CHROMIUM CONVERSION COATINGS FOR IRON AND IRON ALLOYS

摘要

Process of coating iron alloys to improve the corrosion resistance and adhesive bonding strengths. The process comprises treating the iron or iron alloys such as steel with an acidic aqueous solution comprising, per liter of solution, from about 0.01 to 22 grams of a water soluble trivalent chromium compound, about 0.01 to 12 grams of hexafluorozirconate, at least one tetrafluoroborate and/or hexafluorosilicate, at least one water soluble divalent zinc compound and from 0.0 to 10 grams of water soluble thickeners and/or water soluble surfactants.