Process for sealing chromate conversion coatings on electrodeposited zinc
AssigneeEnthone-OMI, Inc.
InventorJose A. O. Maiquez
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Abstract
A process for forming improved chromate conversion coatings on zinc surfaces by treating the zinc surface with an aqueous acidic chromating solution which contains hexavalent chromium and a soluble inorganic salt which has an cation which will form an insoluble organic silicate and, thereafter, treating the thus-formed chromate conversion coating with an aqueous alkaline silicate solution which contains a soluble alkali metal silicate and fluoride ions.
Claims9
A process for forming improved chromate conversion coatings on zinc surfaces which comprises treating the zinc surface with an aqueous acidic chromating solution having a pH of from 0.6 to 2.2 and containing an effective amount of hexavalent chromium and a soluble inorganic salt having an cation which will form an insoluble inorganic silicate, forming a chromate conversion coating on said surface and, thereafter, treating the thus-formed chromate conversion coating with an aqueous alkaline silicate solution having a pH of at least 9.0 and containing an effective amount of a soluble alkali metal silicate and fluoride ions to form an insoluble silicate containing coating on said conversion coating.
Dependencies are inferred from the claim text.