Trivalent chromium passivate solution and process
AssigneeOccidental Chemical Corporation
InventorBento Da Fonte, Jr.
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Abstract
An aqueous acidic solution and process for treating metal surfaces, particularly zinc and zinc alloy surfaces, to impart improved corrosion resistance thereto. The solution contains effective amounts of chromium ions substantially all of which are in the trivalent state, hydrogen ions to provide a pH of about 1.5 to about 2.2, an oxidizing agent, iron ions in combination with at least one additional metal ion selected from the group consisting of cobalt, nickel, molybdenum, manganese, lanthanum and mixtures thereof. The treating solution may optionally further contain halide ions and a wetting agent.
Claims30
An aqueous acidic solution for treating receptive metal substrates to impart a chromate passivate film thereon comprising chromium ions substantially all of which are in the trivalent state, an acid, a solution compatible peroxide or persulfate oxidizing agent, iron ions in combination with at least one additional metal ion selected from the group consisting of cobalt, nickel, molybdenum, manganese, lanthanum, lanthanide mixture and mixtures thereof present in an effective amount to impart increased corrosion resistance to the treated substrate.
Dependencies are inferred from the claim text.