PROCESSES FOR FORMING CHROMATE CONVERSION COATINGS UPON ZINCI FEROUS SURFACES AND SOLUTIONS FOR USE THEREIN

摘要

1341902 Chromating zinc surfaces AMCHEM PRODUCTS Inc 18 Aug 1971 [19 Aug 1970] 38744/71 Heading C7U Zinc or zinc alloy surfaces, e.g. galvanized iron, are chromated in a bath comprising 3 to 20g. Il. chromic acid, one or more acids selected from the group consisting of nitric, acetic and fluosilicic acids, and a source of fluoride, the pH of the bath lying in the shaded area of the Figure. The active fluoride may be hydrofluoric, fluosilicic or fluotitanic acids. The temperature of the bath may be 60 to 125‹F.