Electrolysis: processes – compositions used therein – and methods – Electrolytic coating – Displacement or replacement coating
Reexamination Certificate
1995-06-22
2001-02-06
Mayekar, Kishor (Department: 1741)
Electrolysis: processes, compositions used therein, and methods
Electrolytic coating
Displacement or replacement coating
C106S001250
Reexamination Certificate
active
06183617
ABSTRACT:
FIELD OF INVENTION
The invention relates to self-regulating, halogen-containing additives for acidic electrolytes for dip-tin-plating substrates of aluminum alloys.
BACKGROUND INFORMATION AND PRIOR ART
As is known, for example, from the EP-A-0 278 752, aluminum alloys can be tin-plated by the exchange method with acidic, halogen-containing additives containing tin salt electrolytes. All the halogen compounds named there are used clearly below their solubility in the electrolyte. This means that these compounds, during constant use of the electrolytes, must be analyzed and adjusted regularly (relatively expensive analyses), in order to keep their content within the necessary solubility ranges.
The present invention therefore is directed to the technical problem of finding halogen-containing additives, with which it is possible to keep the effective halogen content practically constant without the need for relatively expensive analyses and corresponding adjustments and thus to achieve a constant tin-plating quality without great expense.
OBJECT OF THE INVENTION
An object of the present invention is an acidic electrolyte, for dip-tin-plating of aluminum alloys, containing tin salts, surfactants and additives yielding flouride ions where fluoride complexes are added as additives yielding flouride ions.
SUMMARY OF THE INVENTION
This objective is accomplished by adding fluoride complexes, for which the optimum effective halogen content corresponds to the maximum solubility of the active substance in the electrolyte, as flouride-containing additives to the electrolytes. At a moderate overdose of the halogen-containing additive and by selecting a concentration, which is slightly above the solubility product under use conditions, a relatively, constant active substance content in the desired range is thus obtained. The fluoride complexes Na
2
SiF
6
and KBF
4
are preferred.
REFERENCES:
patent: 3769182 (1973-10-01), Beckwith et al.
patent: 4170525 (1979-10-01), Kirman et al.
patent: 0278752 (1988-08-01), None
Guhl Dieter
Honselmann Frank
Frommer & Lawrence & Haug LLP
Mayekar Kishor
TH Goldschmidt AG
LandOfFree
Self-regulating, acidic electrolytes for dip-tin-plating... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Self-regulating, acidic electrolytes for dip-tin-plating..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Self-regulating, acidic electrolytes for dip-tin-plating... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2603467