NL8203266A - COMPOSITION AND METHOD FOR ELECTROLYTIC DEPOSITION OF ZINC NICKEL ALLOYS. - Google Patents

Description

»I» I VO 3662

Composition and method for the electrolytic deposition of zinc-nickel alloys.

The present invention relates to the electrolytic deposition of zinc-nickel alloys and more particularly to compositions and methods for electrolytically making shiny, uniform deposits of zinc-nickel alloys with improved corrosion resistance.

It has long been recognized that electrolytic deposits of zinc nickel alloys impart excellent corrosion resistance to the substrates such as steel to which they are applied. In many instances, the corrosion resistance of zinc-nickel alloy electrolytic deposits is superior to that obtained with an electrolytic deposit of nickel or zinc. Therefore, considerable efforts have been made to utilize this superior corrosion resistance.

In general, it has been found to be extremely difficult to obtain a uniform, glossy electrolytic deposit of zinc-nickel-15 alloys. The electrolytic deposits obtained by prior art processes are typically matte and have a gray to black color. The addition to these electroplating baths of one or more brighteners known to be effective in nickel plating or zinc plating has not resulted in a shiny, uniform electrolytic deposition of zinc nickel alloys. Therefore, electrolytic deposits of such alloys have only been widely used in continuous sheet metal. ringing processes, especially for steel strips or wires and the like, in which no high degree of gloss and uniformity in electrolytic deposition is required.

Typical known methods of plating strips with zinc-nickel alloys are described in U.S. Pat. Nos. 4,282,073. 4,313,802? 3,558,442; 3.42Q.754; 2,419,231? British Patent 548,184 and. Japanese Patent Publication 30 28533/1976. Since these methods are incapable of leading to a shiny, uniform electrolytic deposition of an alloy, they are typically operated at a relatively acidic pH, i.e., a pH in the range of about 1-4. Such acidic electroplating baths are not only much more corrosive to the equipment and the environment, 8TffTT6T '------------------------------- * * i 2 'but are also more difficult to handle. This is due to the natural tendency of the pH to rise in the electroplating bath during the electrolysis process. This necessitates the continuous addition of acid to the electroplating bath. to control and maintain the pH within the desired operating range of the pH.

In addition, the prior art methods of plating strips with zinc-nickel alloys typically use a sulfate or mixed sulfate chloride matrix or, in the case of the process of said Japanese patent publication, a cyanide matrix. The electroplating baths described in the latter publication are not only toxic, but create significant ecological problems. and require expensive equipment for treating the waste. The electroplating baths using a sulfate-containing matrix exhibit low current efficiencies due to the poor conductivity of the sulfate ions, requiring more energy for the plating operation. While this may not be a serious problem in the respective continuous plating processes due to the relatively simple shape, ie strip or wire, of the plated substrate, it becomes very significant when a * 20 is desired to have a glossy uniform deposit on a more complex formed substrate is produced.

An attempt to overcome these difficulties becomes. . described in U.S. Patent 4,285,802. As noted in this publication, a zinc-nickel alloy shiny electrolytic deposit containing up to about 5% nickel is produced from a chloride matrix electroplating bath to about 10 to 100 g per liter of zinc and about 0.01 to 10 g per liter of nickel. As brighteners, the electroplating baths of said publication contain a non-rionic polyoxyalkylated surfactant and. an aromatic aldehyde. Although a workable pH range of about 3.0 to 6.9 is disclosed in said publication, actual practice has shown that in this process no completely shiny deposits of zinc-nickel alloys are obtained when the pH is above about 4, 5. In addition, the maximum nickel content of the af-3S setting of the alloy of. 5% not the desired degree of corrosion protection to the substrate. The method of this U.S. Pat. No. 8,203,266-3, therefore, provides at best only a partial solution to the problems of the standard art.

;. The object of the present invention is therefore to provide an improved electroplating bath and an improved method for the electrolytic deposition of shiny uniform deposits of zinc-nickel alloys.

Another object of the present invention is to provide an improved electroplating bath and an improved process which will provide a glossy uniform electrolytic deposition of zinc-nickel alloys with improved corrosion resistance,

Another object of the present invention is to provide an improved bath and process which operate at a less acidic pH than was possible in the standard art to form a gloss. uniform electrolytic deposition of zinc-nickel alloys with excellent corrosion resistance.

These and other objects will become apparent to those skilled in the art from the description of the invention below.

In the drawing, Figure 1 shows a graph containing the results of measurements of the film thickness distribution for electrolytic deposits obtained with the present invention, and those obtained with the standard technique.

According to the present invention, there is provided an aqueous electroplating bath with a pH of about 4.7 to 8.0, 25 wt I bath at least 10 g / l zinc, 15 g / l nickel. contains at least 200 g / l ammonium ions, has a nickel / zinc weight ratio of at least 0.5 and contains a gloss / grain refining amount of a nonionic polyoxyalkylated surfactant. Electrolysis of this electroplating bath results in a uniform fine-grained electrolytic deposition of zinc-nickel alloys which has at least a semi-gloss appearance and contains at least 5% nickel by weight. The electrolytic deposition of nickel alloys thus obtained provides excellent corrosion resistance to the substrate such as steel on which it is plated.

In a preferred embodiment, the electroplating bath of the present invention may also contain an aromatic aldehyde "820T5T6 .....

4 * or aromatic ketone as a secondary brightener to produce a full mirror-like deposit. Instead of or in addition to the secondary brightener, the bath may contain a lower alkyl carboxylic acid or salt thereof as an auxiliary brightener for low current density regions.

More specifically, the electroplating bath of the invention for zinc-nickel alloys will contain at least 10 g per liter of zinc up to the maximum solubility of zinc in the bath. with an amount of zinc from about 10 to about 90 g per liter being preferred. The nickel content of the electroplating bath will be at least 15 g per liter up to the maximum solubility of nickel in the bath, with an amount of nickel from about 15 to about 60 g per liter being preferred. The nickel / zinc weight ratio in the bath: will be at least about 0.5 and preferably about 0.5 to about 10.

The zinc and nickel are typically used in the bath! at least when the bath is initially formulated, in the form of the respective chlorides. Although all bath-soluble chlorides of zinc and nickel can be used, 20 'the zinc is typically added as zinc chloride (ZnCl 3) and the nickel as nickel chloride hexahydrate (ΝΐΟΐ ^ .δΗ ^ Ο). During the operation of the electroplating process, the desired amount of zinc and nickel will often be maintained in the bath using zinc and nickel metal anodes or zinc nickel alloy anodes which dissolve in the bath during electrolysis. However, if the amount of zinc and nickel supplied by dissolving the anode in the bath is not sufficient to maintain the desired zinc and nickel contents, these levels can be maintained by the additional addition of the respective zinc and nickel chlorides to the bath.

The electroplating baths of the present invention will also have at least about 20 g per liter of ammonium ions up to the maximum solubility. of the ammonium ions in the bath, with amounts in the range of from about 20 to about 120 g per liter being preferred. As with zinc and nickel, the ammonium ions are added to the bath as the bath-soluble chloride, preferably ammonium chloride (NH 2 Cl). Although it has been found necessary to have an ammonium ion content. the bath of at least 82 03Τ6Ί ~; To maintain about 20 g per liter, it has been found that the maximum amount of ammonium ions is not critical provided the amount of ammonium ions in the electroplating bath is sufficient to keep the zinc and nickel ions in solution. it has been found that when the minimum amounts of zinc nickel and ammonium ions of 10, 15 and 20 g per liter are not maintained, and / or when the nickel / zinc weight ratio is not at least about 0.5 ,. no satisfactory deposits of zinc-nickel alloys in terms of uniformity and gloss can be obtained. Moreover, no accepted-. 10. bare deposits and plating operations are realized when the zinc, nickel and ammonium components form the bath. are introduced in the form of the sulfates instead of the chlorides.

In order to obtain sufficient conductivity in the electroplating baths of the invention, the total chloride content of these baths should preferably be at least about 90 g per liter and most preferably about 150 to about 300 g per liter. When the desired total chloride content of the bath is not achieved by the addition of the zinc, nickel and ammonium chlorides, other bath-soluble chloride compounds can be added to achieve the desired total chloride content., Typically such will be in the bath soluble chlorides are potassium chloride or sodium chloride, with potassium chloride being particularly preferred.

In addition to the zinc, nickel and ammonium components, the new electroplating baths of the present invention will also contain a nonionic polyoxyalkylated surfactant.

The nonionic polyoxyalkylated surfactant will be present in an amount at least sufficient to provide grain refinement of the electrolytic deposition of zinc-nickel alloys and to provide a deposit that is at least semi-gloss in appearance. will typically be present in the bath in an amount of at least about 0.1 g per liter up to its maximum solubility in the bath, with amounts in the range of about 0.1 to 200 g per liter being preferred.

The nonionic polyoxyalkylated surfactants useful in the composition of the present invention are condensation copolymers of one or more alkylene oxides 82-215-6 and one. other compound, wherein the alkylene oxide has 1 to 4 carbon atoms. * and the resulting copolymer product contains from about 10 to about; 70 moles of alkylene oxide per mole of the other compound. Examples:. of such other compounds which can be alkoxylated are 5 alcohols, including linear alcohols, aliphatic monohydric alcohols.

caves, aliphatic polyhydric alcohols, and phenol alcohols; vet2 hours? fatty amides ;. alkylphenols; alkylnaphthols; aliphatic amines, including: both mono- and polyamines? and such,

Examples of typical suitable surfactants of this type are: A, Nonionic copolymers of ethylene oxide and linear alcohols of the formula of the formula, wherein x represents an integer from 9 to 15 and n an integer from 10 to 50, Surfactants with this structure belong to the Tergitol • 15 ST series available from Uinion Carbide. Examples of such useful surfactants are Tergitol Nonionic 15-S-3, Tergitol Nonionic 15-S-5, Tergitol Nonionic 15-S-7, Tergitol Nonionic 15-; S-9 and Tergitol Nonionic 15-S-12 ..

B. Non-ionic copolymers of ethylene oxide and

20 phenol alcohols of the structural formula: H- (CH-) -Ar-O- (CH_CH_0) CH 2 CH.OH

2 X 2 2 n 2 2 wherein Ar is a benzene ring, x is an integer from 6 to 15 and n is an integer from 10 to 50. Surfactants with this structure are among the Igepol CO surfactants available from GAF Corporation.

C. Non-ionic copolymers of ethylene oxide and coconut fatty acids or alkanolamine coconut fatty acids. Coconut fatty acids are derived from the hydrolysis of coconut oil and generally have the structure formula C H0n + 1 COOH in which n is an integer from 5 to 17.

D. Other specific examples of nonionic polyoxyalkylated surfactants useful in the present invention include, for example, alkoxylated alkyl phenols, for example, nonyl phenol? alkylnaphthols; aliphatic monohydric alcohols; aliphatic polyhydric alcohols, for example polyoxypropylene glycol; ethylenediamine; fatty acids, fatty amides, for example amide of 35. coconut fatty acid; or esters, for example sorbitan monopalmitate. Examples of alkoxylated compounds in the above classes available commercially include "Xgepal" CA 630. a brand name for one;

-0 2 0 3X51: ~ J

7 v ethoxylated octylphenol available from the GAF Corporation;

Brij 98, a brand name for a Shoxylated oleyl alcohol available from ICI American., Inc.? Pluronic F68, a brand name for

; * a polyoxyethylene polyoxypropylene glycol available from. BASF

Wyandotte Corp .; Surfynol 485., a brand name for Shoxylated 2,4,7,9-tetramethyl-5-decyn-4,7-diol available from Air Products and Chemicals, Inc .; Tetronic 504, a brand name for a Shoxylated propoxylated ethylenediamine available from BASF Wyandotte Corp .; Myrj 525, a brand name for a Shoxylated stearic acid available from ICI America, Inc .; Amidoa C-5, a brand name for a polythoxylated coconut acid monoethanolamide available from Stepan Chemical Co .; Tween 40, a brand name for a Shoxylated Sorbitan Palmitate available from ICI America, Inc .; Liponox NCT and; OCS brand names for polyoxyethylene alkyl phenol ethers and polyoxyethylene-15 alkyl ethers available from Lion Corp .; Pluronic L64, a brand name for polyoxyethylene polyoxypropylene glycol and Tetronic 704, a brand name for polyoxyethylene polyoxypropylene ethylene diamine, both of which are available from Products Chimiques Ugine-Kuhlman :; and Ethijnse C / 25, a brand name for Shoxylated amines and Ethomid 0/15, a merfe:; 20 name for Shoxylated amides, both of which are available from Akzo

Chemistry.

Electrolysis of the above-described electroplating baths will result in uniform, fine-grained electrolytic deposits of zinc-nickel alloys that are at least semi-glossy in appearance. to be. While these deposits are generally not completely mirror-glossy, they have a much stronger microcrystalline, uniform appearance than zinc-nickel alloy deposits obtained with the prior art. These deposits provide excellent corrosion resistance to the substrate, such as steel, to which they are applied. are therefore useful in those cases where a mirror-gloss deposit is not required.

If it is desired to produce electrolytic deposits of zinc-nickel alloys with a mirror gloss, this can be accomplished by incorporating an aromatic aldehyde or aromatic ketone as a secondary brightener in the electroplating bath. Such a secondary brightener is added to the bath in an amount sufficient to impart, inter alia, mirror gloss to the deposit up to the maximum solubility of the brightener additive in the bath. Preferably, these secondary brighteners in the electroplating bath in amounts of from about 0.01 to about 2 g per liter.

Typical examples of aromatic aldehydes or aromatic ketones which can be used as secondary brighteners are the aryl aldehydes and ketones, which are ring-shaped; halogenated aryl aldehydes and ketones, and hydrocyclic aldehydes and ketones. Examples of specific compounds that can be used are ortho-chlorobenzaldehyde, para-chlorobenzaldehyde, benzyl methyl ketone, phenylethyl ketone, cinnamaldehyde, benzalacetone, thiophene aldehyde, furfural-5-hydroxymethylfurfural, furfurylideneacetone, furfural-2- furyl) -3-buten-2-one and the like.

The electroplating baths of the present invention, either with or without the secondary brighteners described above, may also contain a low current density region brightener. Suitable brighteners are the lower alkyl carboxylic acids and their bath soluble salts. wherein the alkyl-20 group contains from about 1 to about 6 carbon atoms Although both the acid itself and the bath-soluble salts can be used, in many cases the sodium, potassium, or ammonium salts have the fore A particularly preferred brightening aid for use in the present invention is sodium acetate. These brightening aids are typically used in amounts ranging from about 0.5 to about 25 g / l, with amounts ranging from about 1 to about 10 g / 1 are particularly preferred.

The pH of the electroplating baths of the present invention is from about 4.7 to about 8, with a pH of about 5 to about 7 "being particularly preferred. When the pH of the solution is below about 4.7 The grain refinement of the deposition is poor and a uniform, glossy appearance is not obtained At a pH above about 8, the electrolytic deposition may become hazy and there is a tendency to develop ammonia gas from the plating bath. -Maintaining the pH of the electroplating bath within the desired range can be achieved by the T2T3 2 6 6 '

Jt; 9 addition of ammonium hydroxide to raise the pH or hydrochloric acid to lower the pH.

In some cases, when the bath is at the high end of the pH range. for example at a. pH from about: 7 to about 58, it may also be desirable to include a suitable complexing agent in the bath to prevent precipitation of the zinc and / or nickel metal. Any suitable zinc and / or nickel complexing agent may be used in an amount sufficient to prevent the precipitation of zinc and / or nickel from the bath. Typical examples of useful complexing agents are ethylenediamine-? tetraacetic acid, diethylene tetramine pentaacetic acid and. Quadrol (Ν, Ν, Ν ', Ν'-tetrakis (2-hydroxypropyl) ethylenediamine).

The electroplating baths of the present invention for zinc-nickel alloys are particularly suitable for use in the plating processes, although in some cases they can also be used in barrel plating processes. The plating is typed; pressing performed at cathode current densities from about 4 to about; • * * 80 ASF (43 - 861 A / m1), with a cathode current density of about <10 to about 60 ASF (108 - 646 A / m? -) being particularly preferred. During electrolysis, the electroplating bath is preferably maintained at a temperature in the range of about 25 to 50 ° C, with a temperature in the range of about 30 to 40 ° C being preferred. The anodes used in the electroplating process are preferably anodes of metallic zinc and metallic nickel, although anodes of zinc-nickel alloys can be used. The relative area of the zinc and nickel anodes can be varied to process the desired replacement of zinc and nickel metal in the electroplating bath.

i: In many instances, a zinc to nickel anode ratio of about 9 to 1 has been found to effectively maintain the desired concentrations of zinc and nickel in the electroplating bath.

The invention is further illustrated by the examples. In the examples, the electroplating was performed in a 267 ml Hull cell for 5 minutes at a current of 2 AmpSre and a bath temperature of 35 ° Cr using a zinc anode and a 35- shinier steel sheet as cathode.

8 20Τ2Τ6Π6 ——— 10

example I

It was suggested. an aqueous electroplating bath together containing 100 g / 1 ZnCl 2, 120 g / L NiC 2, O, 240 g / 1 NH 4 Cl and 3 g / 1 ethoxylated 2,4,7,9-tetramethyl-5-decyn-4 7-diol (Surfynol 485). The pH of the bath was 5.5 and the nickel / zinc weight ratio was 0.6

The electrolytic deposition of a zinc-nickel alloy obtained by plating with this bath according to the above procedure was semi-gloss and uniform in appearance.

Example II

For comparison, an electroplating bath was combined; that contained 100 g / l ZnCl 2, 120 g / l NiCl 6 6H 2 O and 240 g / 1 NH 2 Cl.

The nickel / zinc weight ratio in this bath was 0.6 and the pH was 5.5. The electrolytic deposition of a zinc-nickel alloy obtained by electrolysis of this bath in accordance with the procedure described above had an ash gray appearance in the high and medium current density ranges and a black appearance in the low current density ranges, without. traces of shine.

Example III

An electroplating bath was prepared containing 120 g / l 20 ZnCl 3, 160 g / 1 NiC 2 H 2 O, 250 g / 1 NH 2 Cl, 5 g / 1 ethoxylated 2,4,7,9-tetramethyl-5-decyn -4,7-diol (Surfynol 485) and 0.05 g / l benzalacetone. The electroplating bath had a nickel / zinc weight ratio of 0> 7 and a pH of 6.8. The electrolytic deposition of a zinc-nickel alloy obtained by electrolysis of this bath in accordance with the procedure described above had a uniform appearance, and was glossy in the ranges of medium and low current density with only light streaks in the high current density range.

Example IV

An electroplating bath was prepared containing 20 g / l 30 ZnCl, 150 g / 1 ΝΐΟΙ ^ .δ ^ Ο, 15 g / 1 NH ^ Cl, 80 g / 1 KCl, 2 g / 1 polyoxyethylene alkyl phenol ether (Liponox NCT) and 0.04 g / l of benzalacetone. The nickel / zinc weight ratio in the bath was 3.8 and the pH of the bath was 5.0. The electrolytic deposition of a solution obtained by electrolysis of this solution according to the procedure described above. The zinc-nickel alloy had a uniform appearance, was mirror glossy in the medium and low current density regions with only light 820 3T66 i 11 streaks in the high current density region.

Example V

An electroplating bath was prepared containing 80 g / l ZaCl ^ r 80 g / l ΝχΟ ^ .βΗ ^ Ο, 180 g / l NH ^ Cl, 1 g / l polyoxyethylene-polyoxy-5-propylene glycol (Pluronic L64) and 0.02 g / l contained cinnamaldehyde. The nickel / zinc weight ratio in the bath was about 0.5 and the pH of the bath was 5.5. The electrolytic deposition of a zinc-nickel alloy obtained from this bath by electrolysis according to the procedure described above had a uniform appearance and was almost completely mirror-glossy, with only a slight haze.

Example VI

An electroplating bath was prepared containing 20 g / 1 ZnCl 2, 240 g / 1 NiCl 2 .6H 2 O, 60 g / 1 NH 4 Cl, 1 g / 1 polyoxyethylene alkyl amine (Ethendom C / 25) and 0.02 g / 1 ortho: chlorobenzaldehyde . The nickel / zinc weight ratio in the bath was about 6.2 and the pH of the bath was 5.3. The electrolytic deposition of a zinc-nickel alloy obtained by electrolysis of this bath according to the procedure described above had a uniform appearance, and was almost mirror-glossy with only a slight haze.

Example VII

An electroplating bath was prepared containing 120 g / 1 ZnCl 2, 120 g / 1 NiCl 2 .6H 2 O, 240 g / 1 NH 4 Cl, 10 g / 1 ethoxylated 2,4,7,9-tetramethyl-5-decyn-4.7 diol (Surfynol 485) and 0.3 g / l benzalacetone. The electroplating bath had a nickel / zinc weight ratio of about 0.5 and a pH of 5.6. The electrolysis deposit of a zinc-nickel alloy obtained by the electrolysis of this bath according to the procedure described above had a uniform appearance and was mirror-glossy over the entire surface. This electrolytic deposit was analyzed for nickel content and it was found that the nickel content of the deposit in the areas 2 cm, 5 cm and 8 cm were removed from the high current side of the Hull cell plate, respectively. 6 wt%, 7.9 wt% and 10.7 wt%.

Example VIII

An electroplating bath was prepared containing 20 g / l of ZhCl 4, 240 g / l. NiCl2.6E20, 150 g / l NE / Cl, 2.0 g / l polyoxyethylene alkyl amide (Ethomid 0/15) and 0.1 g / l phenylethyl ketone. The bath had a nickel / zinc weight ratio of about 6.2 and a pH of 6.8. The electrolytic deposition of a zinc-nickel alloy obtained by the electrolysis of this solution according to the procedure described above was uniform, completely mirror-glossy, with only light streaks in the high current density range.

Example IX

Three electroplating baths were prepared, which contained 120 g / l ZnCl 4, 140 g / 1 NiCl 3, e, 240 g / 1 NH 4 Cl, 1.0 g / 1 benzalacetone, and 5.0 g / l of a nonionic polyoxyalkylated surfactant . agent 10. In the first bath, the surfactant was polyoxyethylene alkyl ether (Liponox OCS); in the second bath, the surfactant was polyoxyethylene sorbitan palmitate (Tween 40); and in the third bath, the surfactant was ethoxylated propoxylated: ethylenediamine (Tetronic 704). In each bath, the nickel / zinc weight ratio was 0.72 and the pH of the bath 5.5. The electrolysis deposits of zinc-nickel alloys obtained by the electrolysis of these three baths according to the procedure described above were each uniform and mirror-like over the entire surface. i [

. Example X.

An electroplating bath was prepared containing 100 g / l

ZnCl 2, 130 g / 1 NiCl 2 .S ^ O, 200 g / 1 NH 4 Cl, 2.0 g / 1 sodium acetate, 5.0 g / 1 ethoxylated 2,4,7,9-tetramethyl-5-decyn-4,7- diol (Surfynol 485) and 0.1 g / l benzalacetone. The nickel / zinc weight ratio in the bath was 0.67 and the pH of the bath was 5.6. The electrolytic deposition of a zinc-nickel alloy obtained by electrolysis of this bath according to the procedure described above was uniform and completely mirror-glossy over the entire surface.

Example XI j

Using the electroplating baths of Examples 1 and 3 to 10, steel plates were plated with a zinc-nickel alloy deposit to a thickness of 3 µm at a bath temperature of 35 ° C and a cathode current density of about 30 ASF (323 A / m2). The panels thus plated were then subjected to the standard salt spray test (ASTM 'B-117) and it was found that at least about 160 hours of exposure was required before a red rust on the surface of the zinc. nickel alloy - “820 3 26 6” ““ 13.

'J f • gon to develop. Equal steel panels were plated to the same thickness, plated with a commercial glossy electrolytic nickel deposit and with a commercial glossy electrolytic zinc deposit. The nickel plated panels and the zinc plated panels were then subjected to the standard salt spray test and it was found that exposure for only 8 hours and during; 40 hours were required for the development of red rust on the nickel deposit and on the zinc deposit.

The thickness of the electrolytic deposits of zinc-10 nickel alloys obtained according to Examples I, II and VII were. measured at different distances from the high flow side of the Hull cell plate * These thicknesses were then plotted against the distance from the high flow side of the Hull cell plate, as shown in Figure 1. The results show that. the addition of the brightening additives of the present invention does not have any significant adverse effect on the thickness of the electrolytic deposit obtained, over a wide range of current densities, compared to; the deposits obtained from a similar electroplating bath not containing these additives; 8203265 ”!

Claims (9)

An aqueous composition for the electrolytic deposition of zinc-nickel alloys, comprising at least 10 g / l zinc, at least 15 g / l nickel, at least 20 g / l ammonium ions, and a nonionic polyoxyalkylated. surfactant in an amount. 5 sufficient to process grain refinement of the electrolytic deposit of a zinc-nickel alloy and at least to process it; semi-gloss, which bath has a nickel / zinc weight ratio of at least 0.5 and a pH of about 4/7 to about 8.0. The composition of claim 1, wherein the zinc 10 is present in an amount from about 10 to about 90 g / l, the nickel is present in an amount from about 15 to about 60 g / lr, the ammonium ions are present in an amount from about 20 to about 120 g / lr the nonionic polyoxyalkylated surfactant is present. is in an amount from about 0.1 to about 200 g / l, the nickel / zinc weight ratio is about 0.5 to about 10, and the pH is about 5.0 to about 7.0. Composition according to claim 1, also comprising a secondary brightening agent, selected from aromatic amides and aromatic ketones, which secondary brightening agent is present in. an amount sufficient to impart mirror gloss to the zinc-nickel electrolytic deposit. The composition of claim 2, wherein a secondary brightener is also selected selected from aromatic aldehydes and aromatic ketones, which secondary brightener is present. .25 is in an amount from about 0.01 to about 2 g / l. > The composition of claim 1, wherein also a low current density gloss aid is selected, selected from lower alkyl carboxylic acids and salts thereof, said gloss aid is present in an amount of from about 0.5 to about 25 g / l. Assembly according to claim 2, wherein also a low current density. brightener is present, selected from lower alkyl carboxylic acids and salts thereof, which brightener is present in an amount from about 1.0 to about 10 g / l. ---- "8Τ (ΓΤ2Τ5 -: ----- ί) A composition according to claim 3, which also contains a: low current density brightener selected from lower alkyl carboxylic acids and salts thereof, which brightener is present in an amount from about 0.5 to about 25 g / l. A composition according to claim 4, wherein also a low current density gloss aid is present selected from lower alkyl carboxylic acids and salts thereof, said gloss aid being present in an amount from about 1.0 to about 10 g / l. j 9. A composition according to claim 2, characterized in that the nonionic polyoxyalkylated surfactant is ethoxylated 2,4,7V9-tetramethyl-5-decyn-4,7-diol. A composition according to claim 4, characterized in that: the nonionic polyoxyalkylated surfactant is geithoxy— * | taught is 2,4,7,9-tetramethyl-5-decyn-477-diol and the secondary gloss. 15 giving: agent is phenylalacetone. i 11. A composition according to claim 6, characterized in that the non-ionic polyoxyalkylated surfactant is ethoxylated 2,4,7,9-tetramethyl-5-decyn-4,7-diol and the low flow - the density of the shine aid is sodium acetate. 12. A composition according to claim 8, characterized in that; the nonionic polyoxyalkylated surfactant is 2,4,7,9-tetramethyl-5-decyn-4,7-diol, the secondary brightener is benzalacetone, and the low current density brightener is sodium acetate. 13. Process for producing glossy, uniform electrolytic deposits of zinc-nickel alloys. comprising passing an electric current through an aqueous composition according to one or more of claims 1 to 12, between an anode and a cathode, and continuing to pass electric current for sufficient periods of time to deposit the desired electrolytic deposition of a zinc-nickel alloy on the cathode substrate. ίίΤΤΙΙΓ- ~