Acid plating bath and method for the electrolytic deposition of satin nickel deposits
View Patent ↗The plating bath for the deposition of satin nickel deposits according to the present invention contains at least one quarternary ammonium compound and at least one polyether, the at least one polyether having at least one strongly hydrophobic side chain. As compared to prior art plating baths, this acid plating bath has the advantage that it enables a long period of operation or heating and cooling cycles or filtration cycles, makes it possible to perform the filtration needed for continually operating the bath without using active carbon, requires a lower concentration of nickel than prior art baths to produce the satin gloss finish and has a reduced sensitivity to wetting agents that have been dragged in.
1. An acid plating bath for the electrolytic deposition of satin nickel deposits containing a nickel electrolyte, at least one quaternary ammonium compound and at least one polyether, the at least one polyether having at least one strongly hydrophobic side chain, wherein the at least one polyether has the following general chemical formula (I):
wherein
R 1 and R 1′ are independently hydrogen or methyl and can be selected independently in each [(CH 2 CHR 1 O)] a —CHR 1′ —CH 3 unit;
R 3 is hydrogen or a linear chain or branched chain C 1 - to C 18 -alkyl;
a is an integer from 0 to 500;
Z is a grouping selected from the group consisting of a single bond, CH 2 , O, NR 4 , SO 2 , S, NR 4 SO 2 , COO, CO and NR 4 CO, wherein R 4 is hydrogen or a linear chain or branched chain C 1 - to C- 18 -alkyl group;
R 2 is a moiety selected from the group consisting of
and
wherein the chains of the groups having the formulae (II) and (III) can be either linear or branched;
X is a single bond or O:
n and m are integers from 0 to 12, wherein n+m is at least 1;
o is either 0 or 1;
R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are selected independently and are each a moiety selected from the group consisting of hydrogen, a linear chain or branched chain C 1 - to C 18 -alkyl and substituted or unsubstituted phenyl; and
instead of a hydrogen atom the hydrophobic side chain —Z—R 2 is bound to a carbon atom of the unit —CH 2 —CHR 1 —O— or to a carbon atom of the end group —CHR 1′ —CH 3 .
2. The acid plating bath according to claim 1 , wherein Z is O if R 2 is given by the general formula (III) and if X is a single bond.
3. The acid plating bath according to claim 1 , wherein Z is CH 2 if R 2 is given by the general formula (II).
4. The acid plating bath according to any one of claims 1 to 3 , wherein the group —Z—R 2 is bound to a carbon atom of the end group CH 3 of the at least one polyether instead of to a hydrogen atom.
5. The acid plating bath according to any one of the preceding claims 1 - 3 , wherein the at least one polyether is selected from the compounds consisting of
polyethylene glycol octa dimethyl siloxane ether,
polyethylene glycol-polypropylene glycol-hexa dimethyl siloxane ether copolymer,
polyethylene glycol-polypropylene glycol-hexa dimethyl siloxane ether block polymer,
polyalkylene glycol tetra silane ether copolymer,
polyalkylene glycol tetra silane ether block polymer,
polypropylene glycol octa dimethyl silane ether, and
methyl polyalkylene glycol polymethyl siloxane ether.
6. The acid plating bath according to any one of the preceding claims 1 - 3 , wherein the concentration of the at least one polyether ranges from 0.005 to 0.5 g/l.
7. The acid plating bath according to any one of the preceding claims 1 - 3 , wherein at least one primary brightener is additionally included.
8. The acid plating bath according to claim 7 , wherein the concentration of the at least one primary brightener ranges from 0.005 to 10 g/l.
9. The acid plating bath according to any one of the preceding claims 1 - 3 , wherein the concentration of the at least one quaternary ammonium compound ranges from 0.000 1 to 0.1 g/l.
10. The acid plating bath according to any one of the preceding claims 1 - 3 , wherein at least one sulfosuccinic acid ester is additionally included.
11. The acid plating bath according to any one of the preceding claims 1 - 3 , wherein at least one cobalt ion source is additionally included.
12. The acid plating bath according to claim 1 , wherein the acid plating bath is an electroplating bath.
13. A method for the electrolytic deposition of a satin nickel deposit onto a substrate, comprising the method steps:
a) contacting the substrate with the acid plating bath according to any one of claims 1 , 2 , 3 , and 12 ; and
b) setting a current flow between the substrate and an anode.
14. The method according to claim 13 , wherein the plating bath is pumped and/or filtered continuously or discontinuously.