GB721204A - Improvements in and relating to the electrolytic deposition of metals - Google Patents

Abstract

721,204. Electrodeposition of metals. DEUTSCHE HYDRIERWERKE AKT.-GES. Aug. 24, 1951 [Sept. 11, 1950 ; Oct. 30, 1950], No. 19966/51. Class 41. In a process for the electrolytic deposition of metals, organic disulphimides or their watersoluble salts are added to the usual metal salt baths before or during electrolysis. There may also be added to the baths wetting agents stable to heavy metal salts and cation-active compounds which dissociate in aqueous solution to give cations containing at least six carbon atoms. The organic disulphimides are compounds of the general formula R-SO 2 -NHSO 2 R<SP>1</SP> in which the hydrogen atom can be replaced by an alkali metal atom or another cation conferring solubility in water. The radicals R and R<SP>1</SP> each represent an aliphatic, cyclo-aliphatic, or aromatic radical, or a mixed type of these radicals, preferably an alkyl substituted aryl radical. Examples of organic disulphimides are di-p-tolyl disulphimide, dioctylphenyl disulphimide, didodecylphenyl disulphimide, di-octyl disulphimide, p-tolyloctyl disulphimide, p-tolyldodecyl disulphimide, dicyclohexyl disulphimide, dinaphthenyl disulphimide and dibenzyl disulphimide. Examples of wetting agents are water-soluble salts of acid alkyl sulphuric acid esters (fatty alcohol sulphonates), of alkyl sulphonic acids and of alkyl aryl sulphonic acids or the corresponding sulphuric acids. The preferred cation-active compounds have a lipophilic character containing aliphatic, cycloaliphatic, aliphatic-aromatic or cycloaliphatic-aromatic hydrocarbon radicals having at least six carbon atoms and which are surface active, so-called cation soaps, e.g. quaternary nitrogen compounds. Compounds which dissociate in aqueous solution to give cations of a resin-like character may be obtained by condensing oxo compounds such as formaldehyde or acetone, and compounds capable of condensation, containing amino salt groups, e.g. salts of guanidine or dicyandiamidine. The process is stated to improve electrodeposition of metals such as zinc, copper, nickel, tin and brass alloy. For nickel coating small amounts of zinc, cadmium and cobalt salts may be added to the bath. Two examples of nickel-plating baths are given, one including the sodium salt of di-p-tolyl sulphimide and the other including sodium dodecyl sulphate, sodium di-p-tolyl sulphimide and lauryl pyridinium sulphate.