DE2134457C2 - Aqueous electroplating bath for the deposition of nickel and / or cobalt - Google Patents

Description

OH

R — C — SOF
H

wherein M stands for a cation with the valence of 1-2; Jt for an integer from 1 - 2, accordingly the valence of M, stands; and R is hydrogen or a monovalent aliphatic group with 1-16 Carbon atoms, which are optionally replaced by aldehyde, hydroxyl, carboxyl and / or sulfonate groups is substituted.

The invention relates to an aqueous galvanic bath with improved tolerance to metallic ones Impurities and high concentrations of primary luster, which nickel ions and / or Cobalt ions and at least one of the following substances:

a) primary shiners

b) secondary glossers

c) secondary auxiliary shiners

d) anti-wrinkle agents,

and optionally contains conductive and buffer salts.

It is known that in baths of this type the presence of metallic impurities (especially zinc) easily leads to deposition defects during the electrodeposition of nickel and / or cobalt results when bath compositions containing primary and secondary glossers are used. If zinc is the metallic impurity, then that problem is during electrodeposition particularly acute if the secondary glimmer consists of saccharin. In this case, an inadequate Coverage can occur in areas of low current density. Furthermore, streaky deposits can occur can be obtained. Finally, thin, non-metallic-looking precipitates can also be produced will. These defects can not only degrade the appearance of the electroplated article, but also they can also affect the uptake, appearance, luster, etc. of subsequently applied precipitates, such as B. a chromium deposit affect. These harmful metallic contaminants can get into the bath compositions in a variety of ways. The contaminants can for example from the use of technical grade salts in the preparation of the bath composition, or they may be the result of Dissolution of parts that may fall into the bath composition during electroplating.

It can also often happen that excessive supplement amounts are primary due to false alarms Shiners are introduced into a bath for the deposition of nickel and / or cobalt. Since the primary Shiners usually in relatively low levels

ίο concentrations used must be analytical Determining the supplement amounts of these primary shineers should be done much more frequently than this with other additives for the bath, however, if an excessive amount of primary shine is unintentional is added, then the electrodeposition can be just as faulty as if metallic impurities are present.

A wide variety of additives were used in galvanic nickel baths, such as B. sodium bisulfite and sodium thiosulfate to improve the bath composition's tolerance to metallic contaminants (especially zinc) to improve. However, these known additives resulted from the most diverse Reasons only an improvement over time, or they often even resulted in additional difficulties were as serious as the problem they wanted to fix.

The invention had the object to improve a bath of the type described so that it the Production of healthy nickel and / or cobalt containing electrodeposits within a wide concentration range of the primary gloss and / or the metallic impurities allowed

This object is achieved according to the invention in that an aqueous galvanic bath of Initially designated type a hydroxy sulfonate compound of the following formula is added:

OH

R —C-SO ₃ "

wherein M stands for a cation with the valency from 1 to 2, k stands for an integer from 1 to 2, corresponding to the valence of M; and R represents hydrogen or a monovalent aliphatic group having 1 to 16 carbon atoms, which is optionally substituted by aldehyde, hydroxyl, carboxyl and / or sulfonate groups.

The substrates on which the galvanic deposits containing nickel and / or cobalt according to FIG Invention applied can consist of metal or metal alloys, which are usually galvanized become, such as B. nickel, cobalt, nickel / cobalt, Copper, tin, brass, etc. The metal substrates can have a wide variety of surface properties have, depending on the final look desired, which in turn depends on such factors as Gloss, brilliance, leveling, thickness, etc. of the galvanic coating deposited on such substrates Cobalt and / or nickel. Typical substrate metals include ferrous metals such as steel; Copper; Tin; Copper alloys, such as B. brass, bronze, etc .; and zinc, especially in the form of

die-cast zinc parts, which are made of a support other metals, such as B. copper, etc., may have.

The term "primary shimmer" as used here includes N-heterocyclic compounds, acetylenic compounds, active sulfur compounds, dyes, etc. Specific examples for such additives are:

1. N-1-4 dichloropropenyl pyridinium chloride

2. 2,4,6-Trimethyl-N-propargyl-pyridinium bromide

3. N-allyl quinaldinium bromide

4. 2-butyne -, 4-diol

5. Bis-JJ-hydroxyethyl ether of 2-butyne-1,4-diol

6. Propargyl alcohol

7. 2-iv-ethyl-3-butyn-2-ol

8. Thiodipropionitrile

CH ₂ CH ₂ CN

CH ₂ CH ₂ CN

3. You control the internal stresses of the deposits; they shift the tensions in desirably in the direction of pressure.

4. They keep a controlled sulfur content in the galvanic deposition, which in a desirable way increases the chemical reactivity Potential differences in composite covering systems etc. are influenced, which in turn the corrosion is reduced and a better protection of the base metal against corrosion etc. is achieved.

The term "secondary auxiliary gloss" as used herein includes aliphatic or aromatic-aliphatic olefinically or acetylenically unsaturated sulfonates, sulfonamides, sulfonimides, etc. Special ones Examples of such additives are:

25th

Secondary glossers, used individually or in combinations, have one or more of the following functions:

1. They result in semi-glossy deposits or substantial grain refinement of what is customary dull, granular, non-reflective precipitates that get from additive-free baths will.

2. They act as ductilizers when combined with other 'additives, such as primary Shine, can be used.

Sodium allyl sulfonate

Sodium 3-chloro-2-butene-1-sulfonate

Sodium 0-styrene sulfonate

Sodium propargyl sulfonate

Monoallyl sulfamide

(H ₂ N - SO ₂ - NH - CH ₂ - CH = CH ₂ )

Diallyl sulfamide

9. Thiourea

10. Phenosafranine

11. Fuchsin

A primary shimmer may be used when used alone or in combination have no visible effect on the electrodeposition or semi-glossy, fine-grained ones Generate deposits. However, the best results are obtained when using a primary shimmer secondary gloss and / or a secondary auxiliary gloss can be used, as this increases the gloss of precipitation, the rate of gloss formation, leveling, of a glossy deposit resulting current density range, the coverage in areas of low current density, etc. becomes optimal.

The term "secondary shimmer" as used here includes aromatic sulfonates, sulfonamides, Sulfonimides, sulfinates, etc. Specific examples of such additives are:

1. Saccharin

2. Trisodium 1,3,6-naphthalene trisulfonate

3. Sodium benzene monosulfonate

4. Dibenzenesulfonamide

5. Sodium benzene monosulfinate.

NH-allyl

O ₂ S

NH-allyl

7. Allyl sulfonamide

Secondary auxiliary shiners can be used individually (which is common) or in combination. she all have the functions specified for the secondary glossers plus one or more the following functions:

1. You can prevent or reduce the formation of cavities (presumably they act as hydrogen acceptors).

2. You can use one or more secondary shines and one or more primary Luster work together, creating better luster speeds and better

bo leveling is achieved.

3. You can condition the cathode surface by catalytic poisoning, etc., so that the The rate of consumption of the additives (usually the primary shine) is greatly reduced becomes, which improves economy and operational control

The secondary auxiliary gloss also includes ions or compounds of certain metals and Metallciden, such as. B. zinc, cadmium, selenium, etc. which, although not yet general at present can be used to increase the gloss of the deposit, etc. If zinc as a secondary Auxiliary shine is used in bathrooms that have a high Have a degree of zinc tolerance, then the compositions of the invention can particularly can handle excessive amounts of primary shine well.

As used herein, the term "anti-wrinkle agent" refers to a material which prevents or reduces the formation of gas cavities An anti-cavity agent can also work in such a way that

that it is the baths with impurities such. B. oil, fat 5 are applied.

Void means are optional additives that are only optional in combination with one or more of the the above-mentioned additives, namely primary glossers, secondary glossers and secondary auxiliary glossers,

etc., makes it more tolerable, because of it emulsifying, dispersing and dissolving effects on such impurities. However, the Achieving healthier deposits promotes anti-

The hydroxysulfonate additives according to the invention can according to the following general reaction getting produced:

R-C

+ M [HSO ₃ ] _A

OH

RC-SO3
H

where the symbols M, k and R have the meanings given above.

Evaporation and crystallization or separated by using organic solvents The reaction will generally be in aqueous 20.

Media running. The reaction products can be used in Typical examples of this manufacturing process

Be left in the form of an aqueous base solution, the hydroxysulfonate additives are the following,
or the salts can be in crystalline form

O
η HO
I Il NaHSO ₃ - + KHSO ₃ H H - OH H
I. OH OH (a) I Il
H ₂ C = CC + -C-SO ₃ Na I.
- + H ₂ C = C -C-SO ₃ Na
I. ₂ CH ₂ -C-SO ₃ K Il
HC + NaHSO ₃ > H-
I. H H I.
H
J. NaHSO ₃ OH H I.
H OH (b) H ₂ C-CH _2- C-SO ₃ Na SO ₃ Na H O NaHSO ₃ OH
I. NaOOC-C + -> NaOOC- I.
-C-SO ₃ Na H O H (C) CH ₂ CH ₂ -C > CH
I. HO OH HO O
y
C. OH
-C-SO ₃ Li (d)

(e)

H
O

+ 2LiHSO ₃

HC-SO ₃ Li OH

( //
\ H 7th ( 2 1 34 457 : —SO ₃ Na H ₂ O _t H-C = H H I. 8th OH
! H
- SO ₃ NH ₄ \
H 2H-C = CC ^
\ O
J
\
H OH CH ₃ C- H I.
-C-SO, co O
y
H 3 (CHj) ₂ C.
NaOOC-C H (CH _{2 I 2} + NaHSO Ca (HSOj) ₂ - I. 2NaHSO ₃ H -( SO ₃ NaH
I. OH O O
A. ρ H (G) O
y
NaOOC-C 7th
+ CH ₃ \
H \
H 4HSO3 » (H) + NH

Approx

Approx

The hydroxysulphonate additives can be used in aqueous electroplating containing nickel and / or cobalt Baths are used in combination with one or more of the additives indicated above within wide concentration ranges, typically 0.1-5 g / l or more will. When used with the additives described here, then the concentration is preferably about 0.5-2 g / l. Concentrations up to saturation can be used but no particular advantage is obtained thereby. The use of excessively large Quantities generally only add to the running costs of the bath. The hydroxysulfonate additives according to the invention can be added either as solids or in the form of aqueous base solutions. It has been found that the beneficial results of improved tolerance to metallic Impurities (in particular zinc) which are obtained through the use of the additives according to the invention be, even with relatively low concentrations of hydroxysulfonate addition of less than approximately 1.0 g / L are present. At concentrations of not more than about 1.0 g / L has been found to be in cobalt and / or nickel baths, an improved tolerance to zinc for up to several days (4 or 5 Days) is achieved, and that even baths heavily contaminated with metal ions have an improved tolerance Such ions show for at least one day when adding about 1.0 g / l of hydroxysulfonate used

Typical baths containing nickel and / or cobalt (i compositions which, in combination with effective amounts of about 0.5-5 g / l of the hydroxysulfonate additive compounds, about 0.005-0.2 g / l of the primary gloss, about 1.0-30 g / l of the secondary Shine, approximately 0.5-10 g / l of the secondary auxiliary shine and about 0.05-1 g / L of the anti-wrinkle agent can be used are given below.

Typical aqueous galvanic nickel baths, which in combination with effective amounts of the hydroxy sulfonate and the other additives that can be used are the following, in which all concentrations are given in g / i, SöfciTi nothing else is performed:

Aqueous galvanic nickel baths
Table I.

component

Minimum Maximum Preferred

Nickel sulfate 200 500 300 Nickel chloride 30th 80 45 Boric acid 35 55 45 pH (electro- 3 5 4th metric)

A typical sulfamate nickel bath, which according to of the invention includes the following components:

Table 11

component

Minimum Maximum Preferred

Nickel sulfamate
Nickel chloride
Boric acid
pH (electrometric)

330

400 60

55 5

375

45

45

10

A typical fluoborate nickel bath which can be used in accordance with the invention includes the following Components:

Table 111

component

Minimum Maximum Preferred!

Nickel fluorate 250 400 300 Nickel chloride 45 60 50 Boric acid 15th 30th 20th pH (electro- 2 4th 3 metric)

A typical chloride-free sulphate-nickel bath, which can be used according to the invention contains the following components:

Table IV minimum maximum Preferred component 300
35
3 500
55
5 400
45
4th Nickel sulfate
Boric acid
pH (electro-
metric)

10

A typical chloride-free sulphamate nickel bath such as can be used in accordance with the invention contains the following components:

Table V

component

Minimum Maximum Preferred

Nickel sulfamate 300 400 350 Boric acid 35 55 45 pH (electro- 3 5 4th melrish)

It should be noted that the above baths the May contain compounds in amounts outside the specified maximum and minimum, but the best and most economical operation is usually achieved when the connections are in the specified Quantities are available. A particular advantage of the chloride-free baths given in Tables IV and V above is that the deposits obtained are largely free of tensile stresses and high Allow deposition rates when using high rate anodes will.

In the following, aqueous electroplating baths containing cobalt and cobalt and nickel are given, in those the combination of an effective amount of one or more hydroxy sulfonates and the other Additives according to the invention improve the tolerances of the bath to metal ions, such as. B. Zinc ions, even when mixed with other additives, such as. B. iodides can be used. If an ionic Iodide addition is used, then an iodide ion concentration can be used 0.5 - 5 g / l can be used.

Aqueous cobalt baths or cobalt / nickel baths

(all concentrations in g / l unless otherwise stated)

maximum Minium Preferred VI. Cobalt bath CoSO. 7 H ₂ O 400 200 300 CoCl ₂ -OH ₂ O 75 15th 60 H ₃ BO ₃ 50 37 45 VII. Cobalt bath CoSO _{4 7H 2} O 500 300 400 NaCl 50 15th 30th H ₃ BO ₃ 50 37 45 VIII. Cobalt bath with high chloride content CoSO ₄ ■ 7 H ₂ O 350 150 225 CoCl ₂ · _{6H 2} O 350 150 225 H ₃ BO ₃ 50 37 45

21 11th continuation 34 457 Minium 12th Preferred IX. Cobalt / nickel alloy bath 200 300 NiSO ₄ -7H ₂ O maximum 15th 80 CoSO ₄ -7H ₂ O 15th 60 NiCl ₂ - 6H ₂ O 400 37 45 Η, ΒΟ, 225 X. Chloride-Cobalt Bath 75 200 300 CoCl ₂ · _{6H 2} O 50 37 45 Η, ΒΟ, X !. Sulfamate Kobak Bath 500 200 290 Co (O ₃ SNH,), 50 15th 60 CoCI ₂ · 6 H ₂ O 37 45 Η, ΒΟ, 400 75 50

Preferred cobalt-containing bath compositions can contain at least about 30 g / L CoCl ₂ -OH ₂ O, and typically 20-50 g / L CoCl ₂ · _{6H 2} O. Other compounds which have a cation compatible with the bath (ie, a cation which does not interfere with the operation of the bath) and which provide at least 7.5 g / l chloride ion (preferably at least about 9 g / l Cl-) can also be used be used.

The pH of all of the above exemplary aqueous nickel and / or cobalt-containing baths can are maintained at values of 2.5-5.0 and preferably about 3.5-4.5 during electroplating. During the operation of the bath, the pH usually has a tendency to increase. He can with acids such as B. hydrochloric acid or sulfuric acid, etc. can be readjusted. Other buffer components (such as formates, citrates, etc.), can additionally or used instead of boric acid for buffering, if necessary or desired.

The invention will now be explained in more detail with the aid of the following examples.

example 1

A nickel electroplating bath was prepared by placing the following ingredients in water were combined to the stated concentrations (in g / l, unless otherwise stated) achieve.

component Concentralization (g / l) NiSO ₄ - 7 H ₂ O 300 NiCl ₂ · 6 H ₂ O 60 H ₃ BO ₃ 45 Sodium saccharinate (0.6 mol H ₂ O) 3.8 Sodium di-n-hexyl sulfosuccinate 0.125 pH (electrometric) 3.8

A polished brass plate was cleaned and coated in a 267 ml Hull cell with a cell current of 2 A for 10 minutes at a temperature of 50 ^° C. using magnetic stirring. The resulting deposit was uniformly fine-grained and glossy and had excellent ductility and a uniform milky haze. When zinc sulfate was added to the solution in an amount equivalent to 0.08 g / l Zn ⁺ ^ and when the deposition test was repeated, the end of the low current density of about 0-1.6 A / dm ^{2 was} very streaky and dark, with There were places that had a very thin coating. The deposits were sometimes considerably thinner at such points than at the neighboring points.

A quantity of sodium hydroxymethyl sulfonate additive was added to the solution contaminated with zinc, which was sufficient to achieve a concentration of 1 g / l. The separation test was then repeated. An excellent deposit was again obtained, with no streaking and none thin and dark spots in the low current density area were present, indicating that the bath was effectively regenerated.

Example 2

Example 1 was repeated, with 1 g / l of the addition of disodium 1-hydroxy-1,3-propane disulfonate instead of the Additive sodium hydroxymethyl sulfonate was used. It got the same beneficial effects The bath was made insensitive to zinc after contamination with zinc ions, which made the bathroom unusable beforehand.

Example 3

Betspiel 1 was repeated using 1 g / l of the additive disodium a-sulfo-glycolate instead of the additive sodium hydroxymethyl sulfonate . Essentially the same beneficial effects were achieved. The bath composition was made insensitive to zinc by the addition of 1 g / l disodium-sulfo-glycolate. The bath had a considerably increased service life.

Example 4

Example 1 was repeated using 1 g / l sodium l-glycerol sulfonate instead of the addition of sodium hydroxymethyl sulfonate, with im

essentially the same good results were obtained. The bath was after an addition of 1 g / l Sodium-l-glycerine-l-sulfonate insensitive to zinc.

Example 5

A nickel electroplating bath was prepared by placing the following ingredients in water were combined in such a way that the stated concentrations (in g / l, unless otherwise stated) were obtained.

component concentration (g / l) NiSO ₄ · 7H ₂ O 300 NiCl, -6H ₃ O 60 H ₃ BO ₃ 45 Sodium saccharinate (0.6 mol H ₂ O) 3.8 Sodium allyl sulfonate 2.3 2-butyne-1,4-diol 50 mg / 1 Bis-j8-hydroxy-ethyl-ether of 25 mg / 1 2-butyne-1,4-diol N-l ^ -Dichloropropenylpyridinium- 10 mg / 1 chloride Sodium di-n-hexyl sulfosuccinate 0.125 pH (electrometric) 3.8

A polished brass plate was cleaned and coated in a 267 ml Hull cell with a current of 2 A for 10 minutes at a temperature of 50 ^° C. using a magnetic stirrer. The electroplated nickel coating obtained was shiny and heavily leveled and had excellent ductility and coverage in the low current density range. (This was particularly evident from the strong nickel deposition on the back of the plate, which was not facing the anode.)

Such an amount of zinc sulfate was added to the above galvanic nickel bath that a concentration of 0.08 g / l Zn ⁺ + resulted. The coating experiment was then repeated using an identical clean polished brass plate using the same deposition conditions. The nickel-plated plate obtained had a dark, thin and very streaky coating in the area of low current density. It was thus evident that the coverage in the low current density range was drastically reduced due to the presence of the zinc ions.

1 g / l sodium hydroxymethyl sulfonate, Disodium 1-hydroxy-13-propane disulfonate, Disodium 2-sulfo-glycolate and sodium 1-glycerol sulfonate added, followed by electrodeposition under the same conditions as was carried out beforehand. In each case, the excellent deposition properties of the original Bads restored

The electroplating bath was restored five days each · 8 daily for st with continued stirring at 50 ⁰ C heated It deposition experiments were often conducted under the same conditions and with identical plates to determine the way people work bath composition recovered. All additives showed excellent recovery for at least 2 days.

ι Sodium hydroxymethyl sulfonate was even after 5 Effective days in the restored bath composition.

Addition of 1 g / l NaHSO ₃ results in dull, unusable galvanic deposits. This shows that the crowd

in bisulf it is too high.

In another comparative experiment using the zinc contaminated bath of this example an amount of 0.04 g / l sodium bisulfite was added to the contaminated bath instead of the

ii organic hydroxysulfonate additives according to the invention. The zinc tolerance was greatly improved, which was evident when the deposition attempt was repeated using identical clean brass plates and the same deposition conditions as in

2ii showed original uncontaminated bath. However, if the restored bath was ^{stirred at 50 °} C. for about 2 hours, poor deposition properties were obtained again. Thus, this demonstrates the unexpected superiority of the organic hydroxysulfonate additives of the invention in restoring the contaminated bath.

Another experiment was carried out using the zinc contaminated bath of this example. Here, 0.775 g / l sodium bisulfite was replaced

3d of the organic hydroxy-su'fonatzusatzes according to the invention were added. When the deposition test was repeated, the precipitate showed practically no leveling, was ^{veiled in the range of 0 to about 8 A / dm 2} and had cloudy spots in the range of about 0.8-12 A / dm ^2. In addition, the portion of the precipitate where the maximum agitation effect occurred during deposition, that is, within a band extending approximately 1 cm from the underside of the plate, was severely cracked, with the portion having a higher current density Was provided with microcracks, and the part where there was a lower current density was provided with macrocracks. The overcoat also had a dark brown sheen. Although this addition worked against zinc contamination, namely because no streaks appeared in the area of low current density and the deposit was neither thin nor dark, the deposit could not be regarded as a bright nickel deposit. The experiment was repeated with 0.04 g / l sodium hydroxymethyl sulfonate instead of the sodium bisulfite, and a usable precipitate was obtained, that is to say that the effects were almost completely eliminated with low SiruiVidichie and only a dark and thin precipitate in the The range was 0-0.2 A / dm ² .

In a similar comparison, the same contaminated bath composition was found but at 1 g / l Sodium benzene monosulfinate instead of the invention

according to organic hydroxysulfonate compounds used It was found that although the Sodium benzene monosulfinate showed an improved zinc tolerance, but that the leveling properties were completely lost. (For this purpose, it was determined to what extent the galvanic precipitation is a standard scratch topped up the one on the brass plate prior to electrodeposition with an emery paper No. 4/0 was generated.)

Example 6

A galvanic nickel bath was produced by adding the following ingredients to the water given concentrations (in g / l, unless otherwise stated) were combined.

component concentration NiSO ₄ · 7 H ₂ O 300 NiCl ₂ -OH ₂ O 60 H ₃ BO ₃ 45 Sodium saccharinate (0.6 mol H ₂ O) 3.8 Sodium allyl sulfonate 2.3 2-methyl-3-butyn-2-ol 10 mg / 1 N-l ^ -Dichloropropenyl-pyridinium- IO mg / l chloride Sodium di-n-hexyl sulfosuccinate 0.125

1 g / l sodium hydroxymethyl sulfonate, disodium 1-hydroxy-1,3-propane disulfonate. Disodium - «- sulfoglycolate or sodium 1-glycerol sulfonai were excellent Deposits in the range of low current density are obtained which have an excellent gloss, an excellent coverage, a good color and a high Exhibited uniformity and which showed neither thin, nor dark, nor streaky areas.

Examples

A cobalt electroplating bath was prepared by adding the following ingredients to water were combined so that the concentrations given below were obtained (in g / l, if nothing otherwise specified).

20th

Using the deposition conditions given in Example 1, a brilliant, well-leveled, ductile precipitate was obtained, but in the area of low current density at the end of the plate (corresponding to a current density range of about 0-0.8 A / dm ² ) a thin, dark, Uneven and partly streaky surface available.

About 1 g / l of sodium hydroxymethyl sulfonate, Disodium 1-hydroxy-1,3-propane disulfonate, disodium a-sulfoglycclate and sodium 1-glycerol sulfonate added. Then new clean identical brass plates were made using these baths and under Using the same conditions as in Example 1 electroplated to produce nickel-plated plates that excellent gloss, covering, color, and uniformity in the previously defective low current density range of the plates, with none at all Evidence of thin, dark or streaked areas could be found on the panels.

Example 7

In the original uncontaminated bath of Example 1, the following additional organic Additions introduced:

55

component concentration (g / l) CoSO _{4 7H 2} O 300 _{CoCl 2} · 6H ₂ O 60 H ₃ BO ₃ 45 Sodium saccharinate (0.6 mol H ₂ O) 3.8 Bis-jß-hydroxy-ethyl-ether of 50 mg / 1 2-butyne-1,4-diol Sodium allyl sulfonate 2.3 Sodium di-n-hexyl sulfosuccinate 0.025

When a deposition test was carried out as in Example 6, the deposition was unevenly dull and had an extremely brownish hue. However, if 1 g / l sodium hydroxymethyl sulfonate, disodium 1-hydroxy-1,3-propane disulfonate, disodium a-sulfo-glycolate or sodium 1-glycerol sulfonate was added, then a glossy one was good leveled cobalt deposit achieved in every case except for a small dull, iridescent brownish area in the vicinity of the high current density area edge; the area of this area was approximately 1 cm ² . This matt area in the area of high current density was eliminated by adding 0.1 g / l NaI. Without the organic hydroxysulfonate additive according to the invention, at least approximately 0.75 g / l NaI would have been necessary in order to achieve correspondingly good results.

1. Sodium allyl sulfonate 2.3 g / l

2. Bis-j3-hydroxyethyl ether of
2-butyne-1,4-diol 75 mg / 1

3. 2-butyne-1,4-diol 9 mg / l

4. Propargyl alcohol 9 mg / 1

The amounts of the last three primary glossers were approximately 50% in excess of the optimal amount for every component of that particular primary gloss combination.

When a deposition test was carried out as described in Example 1, the characteristics of the deposition in the low current density region were approximately the same as in Example 5. That is, the portion of the plate having a current density of 0.8 A / dm ² , had a thin, dark, uneven and streaky coating. When adding

Example 9

An electroplating bath for a nickel / cobalt alloy was produced by placing the the following ingredients were combined in the specified concentrations.

component

concentration

(g / l)

NiSO ₄ · 7 H ₂ O
NiCl ₂ · _{6H 2} O
CoSO _{4 7H 2} O

300 60 60

230 222/5

17th

continuation

Beslandleil concentration (g / l) H ₃ BO ₃ 40 Sodium benzene monosulfonate 7.5 Sodium-ally I-sulfbnate 2.3 2-M ethyl-3-butyn-2-ol 0.01 N-l ^ -Dichloropropenyl- 0.01 pyridinium chloride Sodium di-n-hexyl sulfosuccinate 0.025 pH (electrometric) 3.8

If a brass plate was placed in this solution in a Hull cell under the same conditions as in Example 1 was electroplated, then the deposit was very unevenly milky to dull, and it only partial coverage in the area of low current density was obtained. If 1 g / l sodium hydroxymethyl sulfonate, Disodium 1-hydroxy-1,3-propane disulfonate, Disodium a-sulfo-glycolate or sodium-1-glycerol-sulfonate was added to the solution in the Hull cell and when the Hull cell test was repeated, then a brilliant and leveled very ductile precipitate was obtained which showed good coverage even in the area of low current density. The one used in this experiment The anode was made of nickel.

Claims (1)

Claim: Aqueous galvanic bath with improved tolerance to metallic impurities and high concentrations of primary brighteners, which nickel ions and / or cobalt ions and at least one of the following substances: a) primary shiners b) secondary glossers c) secondary auxiliary shiners d) anti-wrinkle agents, as well as optionally containing conductive and buffer salts, characterized by a content of a hydroxysulfonate compound of the formula