HIGH PERFORMANCE NON-CHROME PRETREATMENT FOR CAN-END STOCK ALUMINUM

摘要

A chemically and thermally stable chromate free aqueous liquid treatment for metals, especially aluminum, that imparts corrosion resistance as good as that from conventional chromate containing treatments contains water and a fluoroacid selected from the group consisting of H2TiF6, H2ZrF6, H2HfF6, H2SiF6, H2GeF6, H2SnF6, HBF4, and mixtures thereof; a water soluble organic carboxylic acid that contains at least two hydroxyl groups, exclusive of the hydroxyl groups that are part of any carboxyl groups, per carboxyl group in each acid molecule, the water soluble salts of such acids, and mixtures thereof; a source of phosphate ions; and an organic component selected from the group consisting of tannins and amino-phenolic polymers.