GB949601A - Improvements relating to the electro-deposition of brass - Google Patents

Abstract

Bright brass is electrolytically deposited from a solution containing Cu and Zn ions and also Ni and/or Co ions, a substance including an NH2 or NH4 radical, and an alkyl or aryl or an alkyl aryl derivative containing a sulphonyl or sulphonic or sulphonate group or groups. The derivative may contain an imide or amide group or groups. Possible Ni and Co salts are nickel sulphate, chloride, cyanide, potassium nickel cyanide and cobalt cyanide. The derivative may be saccharin, naphthalene disulphonate, naphthalenesulphonic acid-formaldehyde condensation products, an alkyl derivative containing a sulphonate group, benzene sulphonamide, toluenesulphonamide, hexa chloro-o-benzoylsulphimide, benzene sulphonic acid and their salts, p-chloro benzene sulphonic acid and ditoluene sulphonamide. The solution may additionally contain allylsulphonic acid or an alkyl aryl ethylene oxide condensation product such as of the alkylated phenol ethylene oxide type. Electrolysis may be at 95-150 DEG F., 4.5-18 amps./sq. ft. and a pH of 8-13. During deposition the solution may be agitated by air or mechanically. A specific plating solution contains Cu, Zn, Ni and K cyanides, K2CO3, NH4OH, Rochelle salt, saccharin and formaldehyde-naphthalene-sulphonate condensation products. The electrodeposited brass may contain small quantities of Ni. Base metals to be plated may be Zn or Ni, "Mazak" (Trade Mark) or dull brass. Cu anodes may be used with replenishment of the Zn in solution as it becomes exhausted or, using brass anodes, the Cu and Zn concentrations are periodically ascertained and adjusted by adding Cu or Zn cyanide. The electrodeposited brass may be mechanically polished. Specification 949,602 is referred to.