GB832062A - Improvements in electrodeposition of metals - Google Patents

Abstract

832,062. Electroplating. GEIGY CO. Ltd. March 28, 1957 [Jan. 16, 1956], No. 1360/56. Class 41. One or more metals which form complexes with amino- or polyamino-polycarboxylic acids are electrodeposited from an aqueous bath containing such metal or metals and in which there is included as the sole complexing agent hydroxyethyl-ethylenediamine-triacetic acid as such, or wholly or partly in the form of an alkali metal or ammonium salt thereof. Typically from chloride baths at 60‹ C. of pH 11 containing 10 g./l. of the metal to be deposited and using soluble anodes: (1) bright copper is plated on to steel, zinc, or zinc die-castings; (2) zinc is plated on to copper or steel; and (3) lead is plated on to mild steel; while (4) semibright cadmium is plated on mild steel from a chloride bath at 60‹ C. of pH 5.4 or 10.2 containing 10 g./l. of cadmium using a cadmium anode; (5) bright but dark-coloured nickel is deposited on copper from a pH 11 sulphate bath at 60‹ C. using a nickel anode; and (6) coppercadmium alloy or brass are deposited from pH 11 chloride baths using soluble anodes, the baths containing also the above-mentioned complexing agent. Indium may be deposited from a bath containing the complexing agent. Known surface-active agents such as dodecylbenzene sulphonate and known brighteners such as gelatine and coumarin may be added to the baths. Reference is made to the prior use of amino - polycarboxylic acids as complexing agents as disclosed in Specifications 718,574 and 737,713 and in German Specification 731,102. The Provisional Specification also states that the complexing agent may be any amino- or polyamino-polycarboxylic acid containing at least two -CH 2 COOH groups and at least one hydroxyethyl group attached to a nitrogen atom and refers to depositing copper, zinc, and nickel from sulphate baths and cadmium from an aqueous solution of the complexing agent and cadmium carbonate. The deposition of gold and antomony is also referred to.