Electrolysis: processes – compositions used therein – and methods – Electrolytic coating – Depositing predominantly alloy coating
Patent
1994-09-30
1995-08-29
Niebling, John
Electrolysis: processes, compositions used therein, and methods
Electrolytic coating
Depositing predominantly alloy coating
205260, 205274, 205275, 205280, C25D 312, C25D 316
Patent
active
054457246
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to the use of novel phosphonium salts as brighteners for aqueous acidic electronickelization baths.
It is known that acidic nickel electrolytes must contain small amounts of organic substances if the electronickelization is to produce a bright, ductile and surface-planar 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 planarizers, 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 multiring heterocyclic nitrogen bases of the aromatic type in quaternized form such as pyridinium salts, e.g. 2-pyridinium-1-sulfatoethane, as planarizers, i.e. 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. 4,076,600 (3) discloses aqueous acidic zinc electrolyte baths containing phosphonium cations of the formula R.sub.4 P.sup..sym. where R is hydroxyalkyl.
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-butine-1,4-diol, propinesulfonic acid or 3-pyridiniumpropyl sulfonate.
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-pyridinium-1-sulfatoethane or 3-pyridiniumpropyl sulfonate, 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 acidic 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 phosphonium salts of the general formula I ##STR2## where R.sup.1 to R.sup.3 are each 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, 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, or mono- or di(C.sub.1 -C.sub.4 -alkyl)amino, --CO--OR.sup.6, --CO--CH.sub.2 --CO--OR.sup.6, --O--CO--H, --O--CO--R.sup.6, --OR.sup.6, --SO.sub.2 --R.sup.6, --SO.sub.2 --OH, --SO.sub.2 --OR.sup.6, --PO(OH).sub.2, --PO(OH)(OR.sup.6), --PO(OR.sup.6).sub.2, --OPO(OH).sub.2, --OPO(OH)(OR.sup.6) or --OPO(OR.sup.6).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, C.sub.1 -C.sub.4 -alkoxy, halogen, hydroxyl, phenyl and C.sub.1 -C.sub.4 -alkoxycarbonyl, solubility in water.
Suitable C.sub.1 -C.sub.4 -alkyl for R.sup.4 and R.sup.5 and for substituents on phenyl are n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl and in particular methyl and ethyl.
Examples of straight-chain or branched C.sub.1 -C.sub.18 - or C.sub.1 -C.sub.12 -alkyl for R.sup.1 to R.sup.3 and R.sup.6 to R.sup.8 in addition to the abovementioned C.sub.1 -C.sub.4 -alkyl radicals are n-amyl, isoamyl, sec-amyl,
REFERENCES:
patent: 4076600 (1973-02-01), Huebner
"Praktishce Galvanotechnik", Eugen G. Lenze Verlag, Saulgan, 4th Ed. (1984), pp. 268-271 (no month).
Burkhart Bernd
Glaser Klaus
Oftring Alfred
Schwendemann Volker
BASF - Aktiengesellschaft
Niebling John
Wong Edna
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