Electrolysis: processes – compositions used therein – and methods – Electrolytic coating – Depositing predominantly single metal coating
Patent
1995-06-15
1996-10-01
Gorgos, Kathryn
Electrolysis: processes, compositions used therein, and methods
Electrolytic coating
Depositing predominantly single metal coating
205274, 205275, 205280, C25D 312, C25D 316
Patent
active
055608140
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for producing nickelized shaped articles by electrodeposition of nickel from aqueous acidic baths using thiouronium salts as brighteners. The invention also relates to those thiouronium salts which are novel compounds.
It is also known that acidic nickel electrolytes must contain small amounts of organic substances if the electronickelization is to produce a bright, ductile and level deposition of the metal. Such brighteners, which in general are divided into primary and secondary brighteners, are customarily used in the form of combinations comprising a plurality of these agents in order to enhance the effect.
Praktische Galvanotechnik, Eugen G. Lenze Verlag, Saulgau, 4th edition 1984, pages 268 to 271 (1) describes customary brighteners for nickel electrolytes. Although the compounds are classified as primary or secondary brighteners or leveling agents, it is admitted at the same time that clear-cut classification is not always possible. The brightening compounds mentioned are: further hetero atoms such as sulfur or selenium
DE-B-1 191 652 (2) describes single- or multi-ring heterocyclic nitrogen bases of the aromatic type in quaternized form such as pyridinium salts, e.g. 2-(1-pyridinio)ethanesulfate, as levelers, ie. brighteners, for acidic nickel-plating baths. These agents are used together with customary basic brighteners such as benzene-m-disulfonic acid, diaryldisulfimides or sulfonamides.
U.S. Pat. No. 3,630,857 (3) discloses using nitrile group-containing thiourea derivatives of the general formula ##STR1## where the Rs are independently of one another hydrogen, alkyl, alkenyl or alkynyl each of from 1 to 4 carbon atoms and n is from 1 to 4, as brighteners for aqueous acidic electronickelization baths.
In commercial practice, it is customary to combine alkenylsulfonic acids such as sodium vinylsulfonate or sodium allylsulfonate with other brighteners such as propargyl alcohol, 2-butyne-1,4-diol, propynesulfonic acid or 3-(1-pyridinio)-1-propanesulfonate.
However, the prior art agents generally need to be used in relatively high concentrations in the nickel electrolyte baths used.
It is an object of the present invention to provide an improved process for producing nickelized shaped articles using brighteners that are superior or at least equal in brightening to, for example, 2-(1-pyridinio)ethanesulfate or 3-(1-pyridinio)-1-propanesulfonate, but can be used in a lower concentration.
We have found that this object is achieved by a process for producing nickelized shaped articles by electrodeposition of nickel from aqueous acid baths containing as essential constituents one or more nickel salts, one or more inorganic acids and one or more brighteners, which comprises using as brighteners thiouronium salts of the general formula I ##STR2## where R.sup.1 to R.sup.4 are each hydrogen, C.sub.1 -C.sub.18 -alkyl, which may be carboxyl-, C.sub.1 -C.sub.4 -alkoxycarbonyl- or cyano-substituted, C.sub.2 -C.sub.12 -alkenyl, C.sub.2 -C.sub.12 -alkynyl, C.sub.5 -C.sub.8 -cycloalkyl, C.sub.7 -C.sub.12 -phenylalkyl or phenyl which may be substituted by one or two substituents selected from the group consisting of C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, halogen, hydroxyl, phenyl and C.sub.1 -C.sub.4 -alkoxycarbonyl, alkynylene having in each case up to 20 carbon atoms, --CO--OR.sup.5, --CO--NR.sup.6 R.sup.7, --CO--CH.sub.2 --CO--OR.sup.5, --O--CO--H, --O--CO--R.sup.5, --NR.sup.6 --CO--R.sup.5, --OR.sup.5, --SO.sub.2 --R.sup.5, --SO.sub.2 --OH, --SO.sub.2 --OR.sup.5, --PO(OH).sub.2, --PO(OH)(OR.sup.5), --PO(OR.sup.5).sub.2, OPO(OH).sub.2, --OPO(OH)(OR.sup.5) or --OPO(OR.sup.5).sub.2, where -C.sub.12 -alkynyl, C.sub.5 -C.sub.8 -cycloalkyl, C.sub.7 -C.sub.12 -phenylalkyl or phenyl which may be substituted by one or two substituents selected from the group consisting of C.sub.1 -C.sub.4 -alkyl, halogen, hydroxyl, phenyl and C.sub.1 -C.sub.4 -alkoxycarbonyl, and solubility in water.
Suitable C.sub.1 -C.sub.4 -alkyl for R.sup.6 to R.sup.10, R.sup.12 and R.sup.13 and
REFERENCES:
patent: 2892760 (1959-06-01), Gundel et al.
patent: 3630857 (1971-12-01), Du Rose et al.
patent: 3721581 (1973-03-01), Teramura et al.
patent: 3882009 (1975-05-01), Wagener et al.
Protection of Metals, vol. 27, No. 2, Mar./Apr. 1991, pp. 258-261, A. S. Milushkin, et al., "Using New Thiourea Derivatives as Brighteners in Nickel Plating."5
Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
Burkhart Bernd
Glaser Klaus
Oftring Alfred
Schroeder Ulrich
Schwendemann Volker
BASF - Aktiengesellschaft
Gorgos Kathryn
Wong Edna
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