METHOD FOR MAKING A CHROMATE SOLUTION OF GALVANIZED STEEL PLATES

摘要

The chromating solution improves corrosion resistance and reduces black patina on the galvanized steel plates by forming a mixed metal-chromium oxide film. The manufacturing method comprises: adding reducing agents such as ethyl alcohol and methyl alcohol to the chromic acid solutions to obtain chromic ion concentration of 15-25%; adding phosphoric acid of 4˜15g/liter, fluorine compound of 0.1˜10g/liter and phosphate ester potassium salt of 0.01˜1.0g/liter.