IMPROVEMENTS IN OR RELATING TO NICKEL ELECTROPLATING BATHS

摘要

Satin nickel is electro-plated on to an article as cathode from an aqueous acid nickel bath containing also a lustring agent and from 5 to 100 mg/l of a polyether where X represents oxygen, sulphur or an NH group, R 1 and R 4 represent hydrogen, a hydroxyl group or an organic radical, R 2 and R 3 represent an ethylene or propylene residue, and m,n, and p are whole numbers, which polyether at a temperature of from 40 to 75 C. is able to form a finely dispersed emulsion, and effecting electroplating while the bath is maintained in that temperature range. As described the baths are Watts bath to which have been added aromatic sulphooxygen primary brighteners such as benzene-and naphthalene sulphonic acids, diaryldisulphimides, aryl sulphonamides, N-acetyl-o-toluene sulphonamide and saccharin. The polyether compounds include those classes specified in Specification 602, 591 but preferably are polyethylene oxide of M.W. 30,000 an ethylene oxide-propylene oxide mixed polymer of M.W. 10,000 ethylene oxidepropylene oxide mixed polymers reacted with other compounds containing functional groups or polymers formed from propylene oxide and other compounds with reactive functional groups such as polyols. The stability of the emulsions employed are enhanced by the addition of low molecular weight surfactants such sulphates or sulphonates containing short chain alkyl groups, e.g. isohexyl sulphate, isopropylbenzene sulphonate, sodium hexyl sulphate. The plating current density may be from 0À5 to 10 amps/sq dm, and deposits may be provided directly on iron, brass, copper, nickel or plastic which has been made conductive. A subsequent coating of chromium, gold, silver, copper or bright nickel may be subsequently deposited.