Non-chromium passivation method and composition for galvanized metal surfaces
AssigneeBetz Laboratories, Inc.
InventorsJiangbo Ouyang, William L. Harpel
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Abstract
A substantially chromium free composition and method for passivating a galvanized metal surface is disclosed. The passivation treatment which may be rinsed or dried-in-place includes phosphoric acid, boric acid and optionally molybdic acid.
Claims6
A process for passivating a galvanized metal surface comprising contacting the galvanized surface with an aqueous, substantially chromium free, treatment solution consisting essentially of from about 0.5 to 50% phosphoric acid, and from about 0.1 to 5% boric acid.
A passivation treatment solution for galvanized metal consisting essentially of from about 0.5 to 5% phosphoric acid, from about 0.1 to 5% boric acid and from 0 to 0.5% molybdic acid wherein said treatment solution is substantially free of chromium.
A composition for passivating a galvanized metal surface consisting essentially of from about 0.5 to 50% phosphoric acid, from about 0.1 to 5% boric acid and from 0 to about 0.5% molybdic acid.
A process for passivating a galvanized metal surface comprising contacting the galvanized surface with an aqueous, substantially chromium free, treatment solution consisting essentially of from about 0.5 to 50% phosphoric acid, from about 0.1 to 5% boric acid, and from about 0.1 to 0.5% molybdic acid.
Dependencies are inferred from the claim text.