GB983932A - Improvements in or relating to the formation of metal coatings - Google Patents

Abstract

Metal surfaces are coated electrophoretically with a metal, held in suspension in very finely divided form in a water-miscible organic solvent which includes a minor amount of water, preferably 5-40%, and then submitting the coating to mechanical pressure, e.g. in a rolling mill, and heating, e.g. to sinter the metal coating. The suspension, e.g. of aluminium powder of about 10% w/v., is of particle size 1-10m , and preferably includes also a small amount of a salt of the metal being deposited, e.g. aluminium nitrate, dissolved in the water-solvent medium, which may be ethyl or methyl alcohol, isopropanol, or acetone. The sheet, strip, wire or article to be coated which may be of steel or copper, is first cleaned by treatment with acid and alkali electrolytically, and passed through the homogeneous suspension, in which the finely powdered metal may be zinc, brass, aluminium, tin, iron, ferro-chrome, nickel-chrome, cadmium, titanium, or zirconium. The coated sheet is then heated, e.g. to 250 DEG C., and passed through pressure rollers, and then if necessary a further stage of heating up to sintering temperature and also a final pressure rolling stage. The thickness of the coating is thereby reduced by up to 10%.