1,203,072. Coating copper metals. GENERAL ELECTRIC CO. 5 June, 1967 [1 Aug., 1966], No. 25862/67. Heading B2E. A method of coating a copper or copper alloy containing at least 50% by weight of copper or metallic and non-metallic objects having coated on a surface a copper or copper alloy coating comprises applying to the article a coating of a phenol of the formula I wherein X is hydrogen, chlorine, bromine or iodine, Q is hydrogen, a hydrocarbon radical, a hydrocarbonoxy radical, a halohydrocarbon radical having at least 2 carbon atoms between the halogen and the phenol nucleus or a halohydrocarbonoxy radical having at least 2 carbon atoms between the halogen atom and the phenol nucleus, Q' is the same as Q or, in addition, halogen, Z is the same as Q or, in addition, halogen or a silicon-containing moiety which is an organosilane of formula: -(-C n H 2n -)-Si-R 3 , organosiloxanes of formula: and copolymeric organosiloxanes of formula: where K is a hydrocarbon radical, a halogenated monovalent hydrocarbon radical, a cyanoalkyl radical, a hydrocarboxy radical, a halogenated hydrocarbonoxy radical or a radical of the formula I above where Q, Q' and X have the above-defined meanings, R' is a hydrocarbon radical, a halogenated monovalent hydrocarbon radical or a cyanoalkyl radical, a is an integer having a value of from 1 to 3, b is zero, 1 or 2, and n is zero or an integer having a value of from 1 to 18, x and y are integers and a catalyst which is pyridine or a pyridine derivative, and exposing the article to air or a free-oxygen-containing atmosphere, and maintaining the article at a temperature at which the phenol reacts with the oxygen of the air to produce an insulating coating on the copper-containing article. The coppercontaining object may be of brass, bronze, German silver, Muntz metal, red brass, metal silver, or a plastics object containing a copper or copper alloy coating, the plastics being polyvinyl chloride, a phenol-thermaldehyde polymer, polyethylene terephthalate, polymethyl methacrylate, a nylon, a melamine-formaldehyde resin, polystyrene or a polycarbonate of a dihydric alcohol. Numerous suitable pyridine derivatives are specified as well as suitable phenols. A solvent is not necessary but a solvent may be used for ease of operation and numerous solvents are exemplified.