GB1150748A - Improvements in Electrodeposition of Copper - Google Patents

Abstract

1,150,748. Electro-depositing copper. F.I. NOBEL and B. D. OSTROW. May 4, 1966 [July 2, 1965], No.19799/66. Heading C7B. Bright and smooth Cu deposits are electrodeposited from an aqueous acidic solution of at least one Cu salt in which there is dissolved (I) an organic compound selected from (a) water soluble derivatives of 2-thiazolidinethiones i.e. of (b) 2-imidazolidinethiones i.e. of or a water soluble alkyl derivative thereof, and (c) water soluble reaction products of (a) or (b) with an alkyl aldehyde or dialdehyde, and (II) as a water soluble brightener, a compound different from that in (I) and containing in its molecule (a) a C-S group in which the C atom is attached to at least one other hetero-atom selected from S and N and (b) a water solubilizing group selected from a carboxyl group, a sulphonic acid group and their water soluble salts such as the alkali salts. The compounds I (a) and (b) and their alkyl derivatives may be rendered more soluble by first dissolving them in conc. H 2 SO 4 , alcohol or NaOH. Specified aldehydes for making the reaction products (c) are glyoxal, formaldehyde and adipaldehyde. Many examples of the brighteners (II) are specified. They are of the following types:- (i) dithiocarbamic acid derivatives having the general formula where R 1 and R 2 are H, aliphatic or aromatic groups; n is an integer from 1 to 10 and X is a carboxyl group, sulphonic acid group or its water soluble alkali salts. (ii) heterocyclic N compounds in which one or more H atoms linked to C atoms being adjacent to a N atom are substituted by the radical <SP>(IV)</SP> <SP>-S-(CH</SP>2<SP>)</SP>n<SP>-X</SP> in which a CH 2 group may be substituted by a hydroxy group, (iii) organic sulphonic acids having the general formula or (IV) Z = N-R-S0 3 H where Z is a radical comprising a C atom directly attached to a S atom, to an atom selected from N, S and O and to the N atom of - N - R - SO 3 H. (iv) organic sulphonic acids having the general formula G - R - SO 3 H where G is an organic radical which includes a C atom bonded with 3 hetero-atoms one being a S atom through which G is linked with the radical R-SO 3 H. The other two hetero-atoms are selected from N, S and O at least one of the said other hetero-atoms being N or S. R is a bivalent aliphatic radical. Surface active agents may also be included in the bath, e.g. non-ionic wetting agents having the formula (X) R-O-(CH 2 Ch 2 O) n H where R is aryl or alkyl group containing 6 to 20 C atoms and n is an integer from 2 to 100. Other surface active agents which may be used are amines, alkanol amines, amides and carbowax types containing a hydrophilic group and a large number of ethylene oxide groups. The acid Cu bath used in the Examples contains CuSO 4 .5H 2 O 240 g/ l C.H 2 SO 4 60 g/l Examples 1 to 8 and 12 to 14 are of plating a brass sheet. Examples 9 to 11 are of plating a steel sheet provided with a preliminary Cu coating.