WO1997035049A1

WO1997035049A1 - Electroplating solution and method of depositing semi-bright nickel plate from the solution

Info

Publication number: WO1997035049A1
Application number: PCT/EP1997/001260
Authority: WO
Inventors: Gregor Brodt; Norbert Wagner
Original assignee: Basf Aktiengesellschaft
Priority date: 1996-03-15
Filing date: 1997-03-12
Publication date: 1997-09-25
Also published as: DE19610361A1

Abstract

For the galvanic deposition of semi-bright nickel plate on a substrate, the invention calls for an aqueous acid elctroplating solution which (a) contains one or more cyclic N-allyl or N-vinyl ammonium compounds, in particular N-allylpyridinium compounds, as brightener and (b) is essentially free of sulfphur which can be reduced under the electrolysis conditions used.

Description

Bath and process for the electrodeposition of semi-gloss nickel

The invention relates to an improved bath and an improved method for the electrodeposition of semi-glossy nickel, which is distinguished by its ductility, its potential difference to high-gloss nickel, its leveling and its absence of sulfur.

It is well known that nickel can be electrodeposited on various base metals to produce a shiny nickel surface. In order to ensure that the surface is shiny and that the entire system, including the base metal, is protected against corrosion, a highly leveling, semi-shiny and as fine as possible nickel layer is deposited. A so-called duplex process can be used to deposit a high-gloss, less noble nickel layer that ensures the desired surface appearance. The greatest possible potential difference between the two nickel layers guarantees correspondingly good corrosion protection. In other processes, a very thin, so-called sacrificial nickel layer with an extremely low potential is inserted between the semi-gloss and high-gloss nickel layer in order to draw the corrosion that may occur into the depth of the overall system and thus to ensure a permanently good surface appearance. These duplex and triplex nickel layers can in a further process step with a chrome layer, in particular with a micro-cracked chrome layer.

It is also known that various chemical compounds can be used in the galvanic bath to produce semi-gloss nickel layers. However, there are always at least one or two, possibly more, nickel salts such as nickel sulfate, nickel chloride, nickel fluoride and others, and at least one inorganic acid, such as sulfuric acid or boric acid, in the baths.

DE-A 22 15 738 describes a galvanic bath for the deposition of semi-shiny nickel, which a) at least one nickel compound which supplies nickel ions for the electrolytic deposition of nickel, b) as the first cooperating semi-gloss additive, the aliphatic, acetylenic compound 3-hexyne-2,5-diol and c) as the second cooperating semi-gloss additive contains an aliphatic aldehyde selected from formaldehyde, chloral, chloral hydrate, bromal or bromal hydrate. This DE-A describes that largely sulfur-free layers are obtained. However, the process has the disadvantage that the gloss is not uniform over the entire current density range. There are problems with milky deposits, particularly in the high current density range. This bath is therefore particularly unsuitable for the rapid deposition of semi-shiny nickel. Furthermore, the milky nature of the precipitation shows that the base metal may not be completely covered by semi-shiny nickel and thus problems with corrosion protection arise.

By U.S. 3,111,466, U.S. 3,367,854, U.S. 3,414,491, U.S. 3,556,959, U.S.

3,677,913, US 3,719,568 and US 3,795,592 disclose coumarin as an additive in electroplating baths for the deposition of semi-gloss Nickel plating can be used. It is also known that the leveling is significantly improved with increasing coumarin concentration. The best leveling is found at a very high coumarin concentration. However, the high coumarin concentration leads to a high concentration of breakdown products, which leads to dull gray deposits that can only be removed by regeneration of the bath using activated carbon treatment and / or hydrogen peroxide treatment. This is a process that is very time-consuming and thus has a cost-burden on production. If the treatment is not carried out in time, these matt gray deposits lead to adhesion problems of the layers above and to major problems in corrosion protection. In DE-A 33 10 881 the coumarin concentration is reduced to a lower concentration level with the same layer properties by the addition of aromatic hydroxycarboxylic acids, water-soluble acetylene alcohols and their ethylene oxide, propylene oxide and propane sultone derivatives. This leads to significantly longer maintenance intervals for the bathrooms and thus to significant cost savings. Nevertheless, towards the end of the bath's service life, there are still dull gray deposits, which in turn lead to corrosion problems. The regeneration to be carried out then leads to costs and also problems with the disposal of the waste.

Further possible gloss additives for semi-gloss nickel baths are mentioned in various references. Examples include acetic acid in Met. Finishing, £ 3, April 1965, p. 67, sulfosalicylic acid in SU-A 238 982 (cited from CA 071 / 45117a), and potassium biphthalate in US 3,556,959. With all of these components, however, the ductility of the deposited semi-gloss nickel layer leaves much to be desired. When the coated parts are loaded, this can lead to cracks and possibly even to flaking off of the coating and thus to corroding of the base material. The Corrosion protection cannot be guaranteed for the coated parts.

No. 3,677,912 describes the addition of haloalkyl-N-heterocycles to high-gloss nickel baths containing butynediol or butmediol ethoxylates. In the manner described there, these baths are only suitable for producing a cover layer in the system. But excellent leveling, ductility, gloss and coverage are achieved. Due to the content of basic gloss agents containing sulfonate groups in the bath, the potential of these layers produced with them is very low, and therefore these layers alone cannot be used for corrosion protection.

The use of substituted allyl or vinyl pyridinium, quinolinium or isoquinolium compounds in combination with acetylenically unsaturated compounds is described in WO 93/15241. The formulations described herewith serve for the deposition of high-gloss nickel layers. A particular advantage is that the degrees of gloss achieved and the leveling are described. In addition, this method can save a certain amount of chemicals. However, the nickel layers produced in this way are so unfavorable due to the additional components added according to the examples that they can only be used as cover layers in duplex nickel systems.

The object of the invention was therefore to remedy the deficiencies of the prior art, particularly with regard to use in corrosion-protective duplex and triplex nickel systems. In particular, galvanic semi-gloss nickel deposition should be made possible, with which high ductility, high potential difference to high-gloss nickel and good leveling with no sulfur are achieved. This object is achieved by a process for the galvanic deposition of a semi-glossy nickel layer on a support, in which the support is electroplated with nickel in an aqueous acidic, electroplating bath containing a gloss agent, characterized in that an aqueous acidic electroplating bath is used which a) contains one or more cyclic N-allyl or N-vinylammonium compounds according to the general formula (I) as a brightening agent

in which the N ⁺ component of a pyridine, quinoline or isoquinoline

Ring system is, which additionally one or two

Can carry halogen and / or C _r to C ₄ alkyl substituents,

R, R ", R" represent hydrogen or C _γ - to C ₄ alkyl,

R 'is hydrogen or methyl, m is a number from 0 to 4, n is a number from 1 to 4, and x- denotes an n-valent inorganic or organic anion which promotes water solubility,

and b) is essentially free of sulfur which can be reduced under the electrolysis conditions used. The invention thus relates to the use of the compounds of the formula (I), in particular the pyridinium compounds, in semi-glossy nickel baths.

In particular, the bath is free of sulfur with a value of 4 or lower; in particular, it is free of sulfo or sulfonate groups. In contrast, the bath may contain sulfate groups, and this is preferred.

In the method according to the invention, noble nickel layers or semi-gloss nickel layers are formed on the carrier, which have a high potential compared to a reference electrode compared to the potential of an overlying high-gloss layer, in particular a high-gloss nickel layer. In particular, potential differences of more than about 80 mV, preferably more than about 100 mV, are achieved compared to a high-gloss nickel layer located thereover.

A further solution to the problem is a process for the production of coated molded parts, in which an optionally cleaned, electrically conductive surface area of the molded part is provided with a semi-glossy nickel layer from an aqueous acidic galvanic bath, characterized in that the semi-glossy nickel layer is electrolytically coated from a bath - as defined below in its composition - is applied, the surface area preferably being a metallic conductive surface area, in particular a surface area made of copper, iron, brass, steel, stainless steel, cast iron, preferably copper or steel and a carrier made of metal or a carrier made of plastic is used as the carrier, with at least one electrically conductive surface area being located on the carrier.

A support is used for the deposition of the semi-gloss nickel layer, the surface (or surface coating) of which is essentially made of metals, Metal alloys, metallized plastics, preferably Cu, Fe, brass, steel, cast iron or chemically copper-plated or chemically nickel-plated plastics, in particular steel and copper surfaces.

The nickel electrolyte baths described above can be used to produce, in particular, semi-gloss nickel coatings on molded parts made of steel or copper surfaces, but also on molded parts made of other materials, for example brass, which have been customarily pretreated. This is usually done at temperatures of 30 to 80 ° C, preferably 40 to 60 ° C.

The Cp to C ₄ alkyl radicals in the general formula (I) are generally n-propyl, isopropyl, n-butyl, isobutyl, see. -Butyl, tert-butyl and especially methyl and ethyl into consideration as halogen substituent, especially chlorine or bromine.

Examples of alkyl or halogen-substituted heterocyclic ring systems for (I) are:

2-, 3- or 4-methylpyridinium,

2-, 3- or 4-chloropyridinium,

2-, 3- or 4-bromopyridinium,

2-, 3- or 4-ethylpyridinium,

3- or 4-n-propylpyridinium, 3- or 4-iso-propylpyridinium,

3- or 4-n-butylpyridinium,

4-tert-butylpyridinium,

2,3-, 2,4-, 2,5-, 2,6- 3,4- or 3,5-dimethryl pyridimum,

3-methyl-4-isopropylpyridinium, 4-tert-butyl-3-methylpyridinium, 2-, 3-, 4-, 5-, 6-, 7- or 8-methylquinolinium, 2- or 6-bromoquinolinium, 2, 4-dichloroquinolinium, 2,4-, 2,8- or 5,8-dymetylquinolinium and 1-, 3-, 4-, 5-, 6-, 7- or 8-Memyliscκ; hinolinium.

Unsubstituted pyridinium is preferred. The radicals R, R 'and R' "preferably represent hydrogen. The variable m preferably represents 1.

Suitable x-valent anions X ^" are the customary inorganic or organic anions which normally promote the water solubility of organic compounds, in particular chloride, bromide, fluoride, sulfate, hydrogen sulfate, nitrate, tetrafluoroborate, perchlorate, 1-hydroxyethane 1,1-diphosphonate, dihydrogen phosphate, phosphate, formate, acetate, oxalate and tartrate.

Of these, single or double (x = 1 or 2) charged anions, especially fluoride, sulfate, nitrate and tetrafluoroborate, but especially chloride and bromide, are preferred. The number of charges corresponds to (1 to 4) the number of N ⁺ in the ring system, ie there are 2 negative charges of the anion or anions, for example 2N ⁺ .

In a preferred embodiment, cyclic N-allylammonium (pyridinium) compounds of the general formula (Ia) are used,

(la)

in which R \ n and X ^"have the meanings given above.

Acetylenically unsaturated compounds which carry at least one polar functional group, preferably in the α-position of Cp to C ₄ -alkyl radicals, can be used as a further component in the brightening agent. Unfunctionalized acetylenically unsaturated hydrocarbons are unsuitable mainly because of their low solubility in aqueous media and their high volatility. The preferred compounds have the general formula (L1)

R ™ - C ■ C - R ^v 01)

in which the radicals R ™ and R ^v are identical or different and droxyl by Hy¬, amino, C _r -C ₄ - alkylamino or di (C _r to C ₄ alkyl) amino-substituted C _r to C ₄ alkyl denote where hydroxyl groups can be reacted with 1 to 10 moles of a C ₂ to C ₄ alkylene oxide or a mixture of such alkylene oxides and one of the radicals R ™ or R ^{v can} also be hydrogen or C _r to C ₄ alkyl.

Suitable C ₂ to C ₄ alkylene oxides are ethylene oxide, propylene oxide or butylene oxide or a mixture of such alkylene oxides. The degree of alkoxylation is preferably 1 to 3, in particular 1.

In a preferred embodiment, acetylenically unsaturated compounds are used in which the radicals R ™ and R ^{v are} identical or different and denote methyl or ethyl substituted by hydroxyl or dimethyl or diethylamino, hydroxyl groups having 1 to 3 mol of a C ₂ - bis C ₄ alkylene oxide, in particular a C ₂ to C ₃ alkylene oxide, or a mixture of such alkylene oxides can be reacted and one of the radicals R ™ or R ^{v can} also be hydrogen, methyl or ethyl. - 10 -

Examples of compounds of the general formula (II) are:

Prop-2-in-l-ol, but-2-in-l, 4-diol,

Hex-3-in-2,5-diol,

2,5-dimethyl-hex-3-in-2,5-diol,

Prop-2-in-1-ol ethoxylate,

Prop-2-in-1-ol-propoxylate, but-2-in-l, 4-diol-monoethoxylate,

But-2-in-1,4-diol-diethαxylate,

But-2-in-l, 4-diol-monopropαxylate,

But-2-in-l, 4-diol-dipropylate,

1-dimethylamino-prop-2-in, l-diethylamino-prop-2-in, l-diethylamino-pent-2-in-4-ol, l-ammo-l, l-dimethylprop-2-in and

3-methyl-but-l-in-3-ol.

Ethoxylate, monoethoxylate, diethoxylate, propoxylate, monopropoxylate and dipropoxylate are to be understood here as meaning the reaction products with 1 mol of alkylene oxide per hydroxyl group in the compounds of the general formula (II).

The use of hex-3-in-2,5-diol or the combination of hex-3-in-2,5-diol with one or more further compounds from the above group is preferred. If acetylenically unsaturated compounds are used, it is preferred that, based on the sum of i and ii as 100% by weight, the brightener i) 2 to 98% by weight of compounds of the general formula (I) and ii ) 98 to 2% by weight of at least one acetylenically unsaturated compound which carries at least one polar functional group.

Furthermore, the cyclic N-allyl or N-vinylammonium compounds can be used alone or in a mixture with the acetylenically unsaturated compounds together with one or more other brighteners. Examples include chloral, chloral hydrate, bromal, bromal hydrate, aliphatic aldehydes or dialdehydes such as formaldehyde, acetaldehyde, glutaraldehyde or glyoxal, formic acid or acetic acid.

The aqueous-acidic electroplating bath is, in particular, essentially free of base gloss agents.

The aqueous acidic nickel electrolyte baths normally also contain one or usually more nickel salts, e.g. Nickel sulphate and nickel chloride, one or more inorganic acids, preferably boric acid and sulfuric acid, further customary brightening agents and optionally further customary auxiliaries and additives in the concentrations customary for this, e.g. Wetting agents and pore prevention agents. Commonly aqueous acidic nickel electrolytes ("Watts electrolytes") generally have the following basic composition:

200 to 350 g / 1 NiSO ₄ ^• 7H ₂ O 30 to 150 g / 1 NiCl ₂ ^• 6H ₂ O 30 to 50 g / 1 H ₃ BO ₃ . The pH value of the electrolyte baths is usually between 3 and 6, preferably between 4 and 5. A strong mineral acid, preferably sulfuric acid, is expediently used to set this pH value.

The components i and ii mentioned are present in the electrolyte baths in low concentrations, generally from 0.01 to 1.0 g / 1, preferably from 0.05 to 0.7 g / 1. The concentrations of further brighteners are normally in the range from 0.1 to 10 g / 1, in particular 0.1 to 2.0 g / 1.

The invention preferably uses such (aqueous-acidic) electroplating baths, suitable for the deposition of the semi-glossy nickel layers, which contain the following components in g / 1 in the specified quantity range, in particular consisting of:

Component from-to preferred

(1) NiSO ₄ • 7 H ₂ O 250-350 g / 1 280-320 g / 1

(2) NiCl ₂ • 6 H ₂ O 40-80 g / 1 50-70 g / 1

(3) boric acid 30-60 g / 1 40-50 g / 1 (4) compounds of the general

Formula (I) 0.01-1.0 g / 1 0.04-0.10 g / 1

(5) - (8) compounds of the general formula (II)

(5) Hex-l-in-2,5-diol 0-1 g / 1 0.2-0.4 g / 1

(6) 1-Diethylamino-prop-2-in 0-0.05 g / 1 0.01-0.02 g / 1

(7) Prop-2-in-1-ol ethoxylate 0-0.2 g / 1 0.04-0.06 g / 1

(8) But-2-in 1,4-diol dipropαxylate 0-0.3 g / 1 0.02-0.03 g / 1

(9) Formaldehyde or Glyoxal 0.2-1 g / 1 0.5-0.6 g / 1

(10) Chloral hydrate 0.5-2 g / 1 1.0-1.4 g / 1

(11) formic acid 0.1-0.5 g / 1 0.15-0.25 g / 1 (12) sodium salt one

Fatty alcohol ether sulfates 0.1-1 g / 1 0.4-0.6 g / 1 Such baths are also the subject of the invention.

The bath composition according to the invention is distinguished by an extremely noble potential for electroplated nickel layers. The use of the compounds of the formula (I) according to the invention surprisingly leads to this high potential. This leads to extremely favorable corrosion behavior when used in duplex or triplex nickel coatings and especially in connection with a further, if possible, micro-cracked chrome layer, as is shown in the application examples. In addition, the gloss of the nickel layers produced according to the invention is outstanding over the entire current density range, and the leveling is markedly improved compared to the prior art.

The invention further relates to a method for producing coated molded parts, in particular nickel-plated or chrome-plated molded parts. In this method according to the invention, an optionally cleaned, electrically conductive surface area of the molded part is galvanically provided with a semi-glossy nickel layer from an aqueous acidic semi-glossy nickel bath. According to the invention, an aqueous acid bath is used, as is defined in more detail here.

In a preferred embodiment of the invention, such electrically conductive surfaces and such molded parts as are defined above are used in the method for producing the coated molded parts. It is also preferred here to coat a surface made of copper or steel. The electrically conductive surface areas of the molded parts either consist of the metal of the molded part itself or are metallized surfaces of non-conductive molded parts, in particular metallized surfaces on a plastic area of the molded part. It is preferred according to the invention to apply a high-gloss nickel layer to the surface area of the molded part provided with the semi-gloss nickel layer. A sacrificial layer can also be applied between the semi-gloss nickel layer and the high-gloss nickel layer in a manner known per se. Finally, it is preferred according to the invention to then electrolytically provide the high-gloss nickel layer with a chrome layer. As a result, molded parts are produced with a corrosion-resistant, high-gloss chrome surface, as are used in many areas of application of technology.

Examples B1 to B7 and Comparative Examples VI to VIII

The mixtures and comparative mixtures listed in the following tables were used as brighteners in weakly acidic electroplating baths for the deposition of nickel.

The aqueous nickel electrolyte used had the following composition:

300.0 g / 1 NiSO ₄ • 7H ₂ O 60.0 g / 1 NiCl ₂ • 6H ₂ O 45.0 g / 1 H ₃ BO ₃

The respective concentrations of brighteners are given in the respective tables. The pH of the electrolytes was adjusted to 4.2 using sulfuric acid or sodium hydroxide solution.

Galvanized iron sheets were used to assess the gloss and other properties of the deposited semi-gloss nickel layers the coating with semi-gloss nickel in a hydrochloric acid solution was freed of zinc and degreased cathodically in an alkaline electrolyte according to the usual methods. The nickel deposition was carried out in a 250 ml Hull cell at 55 ° C. and a current of 2 A over a period of 10 minutes. The sheets were then rinsed with water and dried with compressed air.

The gloss was assessed optically, with grades from 1 to 5 being awarded. The grading scheme is composed as follows:

5 = excellent gloss

4 = good gloss

3 = moderate gloss

2 = poor gloss 1 = no gloss

The leveling was assessed optically. To do this, the iron sheet is scratched at the bottom using a glass fiber brush approx. 1 cm high. Starting from the highest current density range (I range), the percentage of the leveled range is given.

The veils were assessed optically and described according to the following table.

1 = no veil

2 = very weak veil

3 = faint veil

4 = medium veil

5 = strong veil 6 = very strong veil The potential values were determined against a calomel electrode. For this purpose, a galvanized sheet of iron, which was freed of zinc in a hydrochloric acid solution before coating and degreased cathodically in an alkaline electrolyte by the customary methods, was immersed in the corresponding semi-glossy nickel bath or the comparative bath for 30 minutes and at 3.2 A / dm ² and 55 ° C nickel deposited. The sheet was then immersed in an aqueous solution which contained 50 g / 1 KCl and 0.26 g / 1 CuCl ₂ and was adjusted to a pH of 3.2 by means of acetic acid, and the potential by means of a high-resistance voltmeter measured against the standard electrode.

The corrosion protection values were determined using a salt spray test. For this purpose, a galvanized iron sheet, which had been freed of zinc in a hydrochloric acid solution prior to coating and cathodically degreased in an alkaline electrolyte by the usual methods, was first used for 10 minutes at 2 A / dm ² and 55 ° using the baths according to the invention or the comparison baths C coated with semi-gloss nickel. It was then coated for a further 10 minutes at 2 A / dm ² and 55 ° C. in a commercially available high-gloss nickel bath. In a second series of experiments, a commercially available chrome bath with a micro-cracked 0.3 μm thick chrome layer was then used. The sheets treated in this way were placed in a salt spray tester in accordance with DIN 50021. The sheets were removed once a week and the degree of rust was assessed optically in accordance with DIN 53210. The values given are the mean values for two iron plates treated in the same way.

The following tables show the results of the tests carried out. It can be clearly seen that the semi-glossy nickel layers produced according to the invention have better potential values and corrosion protection values for duplex nickel layers than the prior art. this applies with extremely good gloss and leveling values for semi-gloss nickel layers.

TabeUe 1

Composition of the gloss agent deposits in Example No. (B) and Comparative Example No. (V); Figures in mg / 1

Table 2

Assessment of the sample sheets

Trial gloss 1 leveling veil

B 1 1 5% 5 ä_2 2 25% 4

B_2 3 50% 3

B 4 4 10% 2

B 5 4 50% 2

B 6 4 40% 2

B_7 4 20% 2

V 1 5 90% 1

V 2 5 85% 1

V 3 1 0% 6

V 4 2 5% 4

V 5 3 40% 3

V 6 4 20% 2

V 7 4 20% 2

Y_S 1 5% 6

V 9 1 0% 5

V 10 5 25% 2

Table 3

Determined potential values

Trial value in mV

B 1 + 30

B 2 + 19

! L2 - 20

B 7 - 40

V 1 - 128

V 2 - 180

V 5 - 48

VJ7-66

Table 4

Corrosion protection values determined in degree of rust over time

Table 5

Determined corrosion protection values of the chrome-plated sheets in degree of rust over time

Claims

claims

1. A method for the electrodeposition of a semi-glossy nickel layer on a support, in which the support is electroplated with nickel in an aqueous acidic, glossy electroplating bath, characterized in that an aqueous acidic electroplating bath is used which a) contains one or more cyclic N-allyl or N-vinylammonium compounds according to the general formula (I) as a brightening agent

in which the N ⁺ component of a pyridine, quinoline or isoquinoline

Ring system is, which additionally one or two

Can carry halogen and / or C _r to C ₄ alkyl substituents,

R, R ", R" represent hydrogen or Cp to C ₄ alkyl,

R 'is hydrogen or methyl, m is a number from 0 to 4, n is a number from 1 to 4, and

X denotes an n-valent inorganic or organic anion which promotes water solubility, and b) is essentially free of sulfur which can be reduced under the electrolysis conditions used.

2. The method according to claim 1, characterized in that the gloss agent contains an N-allylpyridinium compound, in which in the general formula (I) R, R "and R '" are hydrogen and m = 1.

3. The method according to claim 1 or 2, characterized in that, based on the sum of i and ii as 100 wt .-%, of the gloss agent i) 2 to 98 wt .-% of compounds of general formula (I) and ii) 98 to 2% by weight of at least one acetylenically unsaturated compound which carries at least one polar functional group.

4. The method according to claim 3, characterized in that the gloss agent as one acetylenically unsaturated compound contains one or more compounds of the general formula (II),

R ™ - C ■ C - R ^v (II)

in which the radicals R ™ and R ^{v are the} same or different and are substituted by hydroxyl, amino, C _r to C ₄ alkylamino or di (C _j _ to C ₄ alkyl) amino C _r to C ₄ alkyl denote where hydroxyl groups can be reacted with 1 to 10 mol of a C ₂ - to C ₄ -alkylene oxide or a mixture of such alkylene oxides and one of the radicals R ^w or R ^{v can} also be hydrogen or C _r to C ₄ -alkyi.

5. The method according to any one of claims 1 to 4, characterized in that the aqueous-acidic galvanic bath is substantially free of Grund¬ shine.

6. Galvanic bath, suitable for the deposition of a semi-gloss nickel layer on a conductive surface, characterized by a content of the following components in the specified quantity range in g / 1

Component from-to preferred

(1) NiSO ₄ ^• 7 H ₂ O 250-350 g / 1 280-320 g / 1

(2) NiCl ₂ ^• 6 H ₂ O 40-80 g / 1 50-70 g / 1

(3) boric acid 30-60 g / 1 40-50 g / 1

(4) Compounds of the general formula (I) 0.01-1.0 g / 1 0.04-0.10 g / 1

(5) - (8) compounds of the general formula (ü)

(5) Hex-l-in-2,5-diol 0-1 g / 1 0.2-0.4 g / 1

(6) 1-Diethylamino-prop-2-in 0-0.05 g / 1 0.01-0.02 g / 1

(7) Prop-2-in-1-ol ethoxylate 0-0.2 g / 1 0.04-0.06 g / 1 (8) but-2-in-1, 4-diol-dipropoxylate 0- 0.3 g / 1 0.02-0.03 g / 1

(9) Formaldehyde or Glyoxal 0.2-1 g / 1 0.5-0.6 g / 1

(10) Chloral hydrate 0.5-2 g / 1 1.0-1.4 g / 1

(11) Formic acid 0.1-0.5 g / 1 0.15-0.25 g / 1

(12) Sodium salt of a fatty alcohol ether sulfate 0.1-1 g / 1 0.4-0.6 g / 1

7. Aqueous, acidic galvanic bath consisting of the following components in the specified quantity range in g / 1

Component from-to preferred

(1) NiSO ₄ ^• 7 H ₂ O 250-350 g / 1 280-320 g / 1 (2) NiCl ₂ • 6 H ₂ O 40-80 g / 1 50-70 g / 1

(3) boric acid 30-60 g / 1 40-50 g / 1

(4) compounds of general

Formula (I) 0.01-1.0 g / 1 0.04-0.10 g / 1

(5) - (8) compounds of the general formula (II)

(5) Hex-l-in-2,5-diol 0-1 g / 1 0.2-0.4 g / 1

(6) 1-Diethylamino-prop-2-in 0-0.05 g / 1 0.01-0.02 g / 1

(7) Prop-2-in-1-ol ethoxylate 0-0.2 g / 1 0.04-0.06 g / 1

(8) But-2-in 1,4-diol dipropαxylate 0-0.3 g / 1 0.02-0.03 g / 1

(9) Formaldehyde or Glyoxal 0.2-1 g / 1 0.5-0.6 g / 1

(10) Chloral hydrate 0.5-2 g / 1 1.0-1.4 g / 1

(11) Formic acid 0.1-0.5 g / 1 0.15-0.25 g / 1

(12) sodium salt one

Fatty alcohol ether sulfates 0.1-1 g / 1 0.4-0.6 g / 1.

8. A process for the production of coated molded parts, in which an optionally cleaned, electrically conductive surface area of the molded part is galvanically provided from an aqueous-acidic galvanic bath with a semi-glossy nickel layer, characterized in that the semi-glossy nickel layer is electrolytically produced from a bath

Claim 6 or 7 is applied, wherein preferably a metallically conductive surface area, in particular a surface area made of copper, iron, brass, steel, stainless steel, cast iron, preferably copper or steel, is used as the surface area, and a carrier made of Metal or a carrier made of plastic is used, at least one electrically conductive surface area being located on the carrier.

9. The method according to claim 8, characterized in that a high-gloss nickel layer is electrolytically applied to at least a part of the surface area of the support bearing the semi-gloss nickel layer. is brought, wherein a sacrificial layer is preferably applied between the semi-gloss nickel layer and the high-gloss nickel layer.

10. The method according to claim 9, characterized in that a chromium layer is applied electrolytically to at least part of the surface area of the support bearing the high-gloss nickel layer.