GB474064A - Improvements in or relating to metal surfacing - Google Patents

Abstract

A corrosion-resisting layer is formed on a metal article, such as a sheet, rod, wire, or casting, by covering the article by brushing, spraying, or dipping with a mixture of a finely divided coating material, which may be a metal or a non-metal, and a vehicle which will volatilize at the temperature of treatment, and then heating the article to a temperature less than the fusion temperature of but not less than the normal annealing temperature of the coating material. The coating material is absorbed into the surface layer of the article and, if sufficient coating material is present in the mixture, this alloy layer may be covered by a layer of the coating material. In an example, a corrosing-resisting layer is formed on iron or steel by covering it with a mixture of finely divided aluminium and a vehicle formed by heating chinawood oil, adding to the oil while cooling thickened turpentine or Venice turpentine, and, when cold, adding a thinning liquid such as turpentine or turpentine gum spirit. A flux, e.g. a solution of boric acid in turpentine, may be added to the mixture. The iron or steel covered with the mixture is then dried and heated to a temperature between about 750 and 1100 DEG F., the drying and heating being preferably effected in a neutral or reducing atmosphere or in a partial vacuum. The covering and heating may be repeated, coarse aluminium being, if desired, included in the mixture. The coating material may be present in the form of flakes, granules, or a mixture of flakes and granules. Various materials may be used for making the vehicle, e.g. oils such as castor oil, gums, resin solutions, cellulose solutions, nitrocellulose, rubber and similar materials, metallic soaps, and emulsions such as rubber-latex mixtures. Borax may be used as the flux instead of boric acid and the turpentine in the specific example may be replaced by linseed oil, acetone, or alcohols. Coating materials referred to are aluminium, copper, bronze, lead, zinc, tin, tantalum, cobalt, tungsten, molybdenum, beryllium, titanium, nickel, manganese, silver, uranium, vanadium, zirconium, chromium, alloys such as phosphor-copper, silicon-copper nickel-copper, nickel-silver-copper, and stainless steel, and the non-metals carbon, boron, and silicon. The treatment of iron or iron alloys with aluminium, copper, or bronze as coating material, of copper or bronze with aluminium, and of iron with carbon is specifically referred to.