GB1304950A - - Google Patents

Abstract

1304950 Electro-coating chromium surfaces with an organic coating M & T CHEMICALS Inc 7 Dec 1970 [11 Dec 1969] 58104/70 Heading C7B A corrosion resistant electro-coated article is prepared by electro-phoretic deposition on to an article bearing a chromium coating of at least 0À001 micron from a bath containing 10-500 gm/l chromic acid (Cr O 3 ) and an organic coating material which will react with the chromium surface when deposited thereon. The chromium surface may be electroplated on to a metal base, e.g. iron, steel, brass, bronze, copper, zinc, aluminium, magnesium or nickel, or may be chemically deposited on to non-conductive bases, e.g. wood or plastics material. Electro-deposition of the chromium may take place from a chromic acid bath, containing as catalysts sulphate ion, e.g. as sulphuric or as strontium sulphate, and fluoride or a complex fluoride, e.g. silicofluoride, fluoaluminate, fluozirconate, fluotitanate or fluoborate. The organic coating material used may be of positive or negative polarity, and various suitable resins are listed, including alkyd, acrylate, epoxy, phenyl-formaldehyde, styrene, polyamine and polyester resins. The bath may include binding agents, fillers, pigments, solvents, dyes, etc; and preferably takes the form of a aqueous colloid or emulsion.