PROCESS FOR SEALING CHROMATE CONVERSION COATINGS ON ELECTRODEPOSITED ZINC

摘要

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 a 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.