DE2333069C2 - Acid, aqueous bath for the galvanic deposition of a shiny nickel-iron coating - Google Patents

Description

O ₁ S - RS - Λ

contains where

A water peat. -R SC ₁ -. -S-Rj-SO, or R ι denotes, where R. R, or R, a saturated alkylene .einc Arvlen- or an aralkyl group and

R, a \ lkyi-. Arvl or aralkyl group means

6 Bad n.ich one of claims I to 5, characterized in that there is also an organic Sultitt the formula

45

R,

contains, in which

C S R,

w)

R, hydrogen (Hler a carbon atom of an organic group.

R ■ nitrogen or a carbon atom of an organic him group and

U _: a Kohlensli'lfalom of an ori: .mischen group

mean.

7. Bath according to claim 6, characterized in that it is as an organic sulfide 2-AminothiazoI in a concentration of 0.001 to 0.005 g / l

8. Bath according to claim 6, characterized in that it is the organic sulfide isothiourea-s-propionic acid in a concentration of 0.001 to Contains 0.010 g / l.

9. Bath according to claim 6, characterized in that it is a compound of the organic sulfide formula

HC - N H

HC CN-CH ₄ O

SO ₃ Na

contains in a concentration of 0.001 to 0.060 g / l.

The invention relates to an acidic aqueous bath for the galvanic deposition of a shiny nickel-iron coating on a corrosion-sensitive bath Substrate with a content of nickel, iron and possibly cobalt ions, a bath-soluble nickel brightener in the form of a sulfo-oxygen compound, at least a bath-soluble complexing agent having at least one carboxyl and one hydroxyl group and optionally a buffer and / or a surface-active compound.

Electrulytic coatings have been used for many years Made of nickel used as a substrate for the electrodeposition of chromium to metal surfaces to impart satisfactory corrosion resistance. LIm the cost of making one To lower a satisfactory decorative coating, attempts have been made to manufacture various nickel alloys. Iron-nickel coatings were made previously used for electrodeposition of electromagnetic films. These films show im generally extremely thin surfaces. are usually not decorative and are not exposed to corrosive conditions

Fin bath of the type described at the beginning is made of chemical / entralblatt (1% 7). No. 30. Ref 2404 known According to this publication it is called Main gloss image is used with formaldehyde, while sulfo-oxygen bonds can optionally be used as additional gloss / formers the /us.it/ of maldehyde, the nickel fisent coating has a slight or cloudy appearance. The formaldehyde also acts as a reducing agent. Brighteners and Finishing Agents

As can also be seen from the publication, work is carried out at a pH of 4-8 and a current density of 2-10 A / dm ² . Despite this relatively low current density, an acceptable iron-nickel coating is achieved according to the publication, ie a coating with sufficient gloss, sufficient smoothness and sufficient ductility. However, these results are only achieved if an appropriate mence of formaldehyde is present.

To what extent such iron-nickel coatings in terms of gloss, smoothness and ductility, however, with coatings made of 100% nickel are comparable cannot be found in the publication.

The invention is based on the object of providing a bath ϊ with which iron-nickel coatings can be deposited which are comparable to 100% nickel coatings in terms of gloss, smoothness and ductility and which have good corrosion resistance .

According to the invention, this object is achieved in a bath described at the outset in that the ratio the nickel and iron ions in the bath is 5 to 50: 1, so that the bath is 0.5-10 g / l of the nickel brightener contains that the complexing agent is not a redu- is ornamental aliphatic carboxylic acid with 1-3 carboxyl groups, 2-8 carbon atoms and 1-6 hydroxyl groups and is present in an amount of 10-100 g / l and that the ratio of the concentration of the complexing agent to which the Eiica ions in the bath is 3 to 50: 1 and the bath has a pH of 2.5 to 5.5.

Advantageous further developments of the invention are described in the subclaims.

Invention According to a different route for the production of high-quality iron-nickel coatings than is evident from the publication mentioned above. According to the invention, the complexing agent is not used in conjunction with formaldehyde, but rather together with a sulfo-oxygen compound as a nickel luster former. »Such glaziers are known as such and are used in particular when separating coatings from 100% nodules! used. The above-mentioned publication also teaches the replacement of such nickel brighteners, but only in connection with formaldehyde. It is new and completely surprising for the experts that such brighteners, when used in conjunction a Komplexierungsmiltel mil in the deposition v "n iron-nickel coatings are used in besiimmten working conditions of the bath * o these coatings excellent gloss, smoothness and impart ductility properties. It is to the merit of the present invention that these working conditions have been precisely defined, specifically with regard to the following parameters: <5

a) Ratio of nickel · iron ions in the bath;

b) quantitative precipitation of the nickel brightener;

c) qualitative and quantitative definition of the complexing agent;

d) ratio of the concentration of the complexing agent for the concentration of iron ions in the bathroom; and

e) pH values of the bath.

It is essential that when following ">"> The inventive teaching 'quality at an Stromdichtebcrcich of 1.1 -7.5 A / dm iron NJckcl-l'berzüge be obtained. Fun such a favorable effect was not to be expected from Fachwell, especially according to "Handbuch der Galvanotech- * o nik", Vol. II. 19, p. 467 in an example of such an iron-nickel bath to which citric acid was added as a complexing agent with a current density of 40 Λ / dm '. From this reference it is known in principle, such a ^ft '' baths z.ur prevent oxidation of the divalent iron ions and thus add oiler sodium citrate to prevent the failure of iron hydroxide citric acid. In addition, it is stated there that a certain ratio of cathodic current density and pH value must be maintained in order to deposit a usable precipitate. In the example given below, a current density of 40 A / dm ^J is used at a pH value of 3.0. If the conditions according to the invention are observed, however, a current density range of 1.1-7.5 is already achieved at the same pH value A / dm ^{1 achieved} excellent results. This is due not least to the use of the special nickel brightener according to the invention.

The bath according to the invention can also be used for electrical purposes Deposition of a shiny nickel-E η coating is used on a plastic substrate will. In general, the plastic substrate, for example acrylonitrile-butadiene-styrene, polyethylene, polypropylene, polyvinyl chloride, phenoliormaidehyd, pretreated by applying a conductive metal coating, for example from Nod! or copper. The Nickei iron coating is then applied as the next coating to the conductive metal coating

Any compound which is soluble in the bath and which contains iron or nickel can be used to introduce the iron and nickel ions into the bath, provided that the anion does not adversely affect the bath. Inorganic nickel salts such as nickel sulfate are preferred or nickel chloride, as well as other nickel salts such as nickel sulfamate, are used. If nickel sulphate salts are used, they are usually present in amounts of 40 to 300 g / l (calculated as nickel sulphals 6H _; O). Nickel chloride can also be used, and it is generally used in an amount ranging from 80 to 250 g / l. The chloride or halide ions are used in order to obtain a satisfactory conductivity of the solution and at the same time to impart satisfactory corrosion properties to the soluble anodes.

Inorganic iron salts, such as iron (II) sulfate or iron (II) chloride, are preferably used. These Salts are preferably used in an amount of 3 to 60 g / l. One can also use other soluble ones in the bathroom Iron salts, such as soluble iron (II) fluoroborate or sulfamate. use.

The complexing agent used is a non-reducing aliphatic carboxylic acid with 1-3 carboxyl groups, 2-8 carbon atoms and 1 6 hydroxyl groups. It is used in an amount of 10-100 g / l. Suitable complexing agents are, for example, citric acid. Malic acid. Gluconic acid, glucoheptonate, Glycolic acid and the water-soluble salts of these compounds, such as the ammonium and alkali metal salts (Potassium, sodium, lithium salts).

The iron can be in the bath as the salt of the complexing agent to be introduced.

With carboxyl group the group -COOFl is meant. In solution, however, the proton dissociates from the carboxyl group away. therefore the term carboxyl group should also include this group.

The purpose of the complexing agent is to remove the metal ions, especially the iron (II) and iron (III) ions, keep in solution. When the pH in conventional Watts baths is above a value of approximately 3.0 increases, iron (III) ions have a tendency to precipitate out of iron (IIl) hydroxide. The complexing agent prevents the formation of a sleep

ges and thus allows the iron and nickel ions are available for electrolytic deposition.

Due to the operating parameters, the pH value of the bath when using a complexing agent is in the range from 2.5 to 3.5. Eevory.-j _a i vitj a range from 3 to 3.5.

The temperature of the bath can range from 49 to 82 ° C. It is preferably 71 ⁰ C.

The average cathode current density is in the range of 1.1-7.5 A / dm ² . It is preferably 4.8 ydm ² .

The concentration of the complexing agent must be at least three times the concentration the iron ions in the bathroom. The ratio of the concentration of the complexing agent to that of the iron ions in the bathroom should be 3 to 50: 1.

The bath can also contain various buffers, such as boric acid or sodium acetate, in amounts from 30 to 60 g / l, preferably 4P g / l. The bath can be operated without stirring or it can be mechanically stirred as well as air circulation, cathode rod guide or similar application.

As far as the nickel brightener is concerned, various sulfo-oxygen compounds can be used. Oeeignet sulfo-oxygen Connect, for example, ^and hang as they are described as brighteners of the first class in "M>'<jeinElectroplating" by John Wiley and Sons, 2nd Aufli'He, S. 272nd

The amount of sulfo-oxygen compound that is used in of the present invention is in the range of 1.5 to 10 g / l. It was found df 3 Saccharin can be used in amounts ranging from 0.5 to 5 g / l and is shiny, ductile Coating results. Will other sulfo-oxygen compounds such as naphthalenetrisulfonic acid, sulfobenzaldehyde or dibenzenesulfonamide is obtained a good gloss, but the ductility is generally not as good as that of saccharin. In addition to the Sulfo-oxygen compounds described above can be other compounds such as sodium allyl sulfonate. Benzene sulfinite, vinyl sulfonate, jS-styrene sulfonate and use cyanoalkanesulfonates (containing 1 to 5 carbon atoms).

As sulfo-oxygen compounds, for example, unsaturated, aliphatic! "Uronic acids, mononuclear and binuclear aromatic sulfonic acids, mononuclear aromatic sulfinic acids, mononuklcare aromatic sulfonamides and sulfonimides can be used.

It has also been found that acetylenic nickel molecules can be used in amounts in the range from 10 to 500 mg / l. Suitable connections are the acetylenic sulfo-oxygen compounds. described in the l'S-PS 28 00 440 are. These nickel brighteners are oxygen-containing, acetylenic sulfo-oxygen compounds. Other acetylenic nickel brightening additives are those described in US Pat. No. 3,366,557, such as the polyethers, those produced by the condensation reaction of acetylenic alcohols and diols, for example propargyl alcohol or butynediol and the lower alkylene oxides. such as epichlorohydrin, ethylene oxide or propylene oxide are formed.

It has also been found that heterocyclic 6 ^r ) quaternary nitrogen or betaine-nickel brightening additives can be used in amounts ranging from 1 to 50 mg / l. Suitable compounds are nickel lacquers as described in US Pat. No. 2,647,866 and the heterocyclic nitrogen-suironates described in US Pat. No. 3,023,151. Preferred compounds described in these literature references are the quaternary pyridine compounds or betaines or pyridinesulfobetaines. Suitable quaternary compounds that can be used are quinaldine propane sultone, quinaldine dimethyl sulfate, quinaldinallyl bromide, pyridinallyl bromide, isoquininaldine propane sultone, isoquinaldine dimethyl sulfate or isochindldinallyl bromide.

Sometimes areas of low current density may not be completely shiny. Around the current density range To extend the baths according to the invention, other organic sulphide nickel brighteners are used used in amounts ranging from 0.5 to 40 mg / l

These organic sulfides have the formula

R ₁ -N = CSR ₃

R, hydrogen or a carbon atom of an organic Group,

R _{2 is} nitrogen or a carbon atom of an organic group and

Rj is a carbon atom of an organic group

mean. R, and R, or R ₃ can be bonded to one another via a single organic group.

More precisely, one uses as organic Sulphide compounds that are soluble in the bath, 2-aminthiazoles and isothioureas of the formula

R ₄ -C - N

Il Il

R ₅ -C C-NH-R ₆
S.

C — S — R,

R ₇ -N

R, -N
H

wherein

R ₆ denotes H, lower alkyl sulfonic acid groups, aryl sulfonic acid groups, lower alkoxyarylsulfonic acid groups and the salts thereof,

R ₄ and R _{5 are} H, halogen, lower alkyl groups and the divalent group

-C = C-C = C-

! III

Rio Rio Rio Rio

mean in which the radicals R ,,, II, halogen and lower Aii ·· ;. ! group: mean, and in what
R., means lower alkyl sulfonic acid groups and lower alkyl carboxylic acid groups and the salts thereof and wherein

R and R _s M, halogen, lower alkyl groups and the divalent group

R ₁₁

Q fj

Ru Ru

mean in which the R _n groups mean II, Ilaingen and lower alkyl groups.

The term "halogens" is intended to be chlorine, bromine, fluorine and iodine, although chlorine is generally preferred. The term "lower alkyl or alkoxy

Table I.

groups «is intended to encompass groups containing 1 to 6 carbon atoms in a straight or branched chain, groups with 1 to 4 carbon atoms being preferred. The term "sulfonic acids" or "carboxylic acids and their salts" is also intended to include those sulfonic acids and carboxylic acids which contain halogen substituents in the alkyl, alkoxy or aryl groups, examples of salts being the alkali metal salts such as sodium, potassium, lithium -, cesium and rubidium salts, especially the sodium salt. If R 1 and R <are connected to one another in the divalent group above, a six-membered ring is formed, and if R- and R * are connected to one another, a five-membered ring is formed.
Suitable compounds are those of the I ormel

Con / entr. Area (a / l)

(I) UC N

HC C-NH,

0.001 to 0.005

0.001 to (».02

HC - N H

HC CNC ₂ H ₄ O
S.

N H

<f

C - N - (CH ₂ ), - SO ₃ Na

(5) HN

C - S - (CH ₂ ), - COOH

H ₂ N

(6) H ₂ CN

C - S - (CH ₂ ) "- SO ₃ Na

H ₂ CN
H

η = 1 to 4

0.001 to 0.06

0.001 to 0.02

η = 1 to 2

0.001 to 0.01

η = 1 to 4

0.001 to 0.015

The compound Π), 2-aminothiazole, and the compound (2), 2-aminobenzothiazole, can with bromoethanesulfonate, Propane sultone, benzyl chloride, dimethyl sulfate, Diethyl sulfate, methyl bromide, propargyl bromide, Ethylene dibromide, allyl bromide, methyl chloroacetate, sulfophenoxyethylene bramide are implemented. the the latter compound can be implemented, for example, with the compound (1), whereby the connec-

manure (3) receives; connections are formed, which give even better results than compounds (1) and (2). One can also replace the connections (1) and (2) substituted 2-aminothiazoles and 2-aminobenzothiazoles such as 2-amino-5-chlorothiazole and 2-amino-4-rncihyltbiazo! use. About connections how to prepare (5) and (6), you can thiourea with propiolactone, butyrolactone, chloroacetic

acidic, chloropropionic acid, l'ropansulton iitul dimethyl sulfate realize. One can also use Phcnylthioharnsloff. Methylthiourea. Allyl thiourea and others similarly substituted thioureas in the reactions use, whereby V'crbiiuiungcn are formed, which are similar to those of the compounds of type (5t and (6)).

V> z above nickel brighteners must be soluble in the bath, and they will be in the had. when an acid is involved. as an acid itself or as a salt with cations soluble in the had, such as ammonium ions or alkali metal ions, such as lithium. Potassium or sodium ions.

The shiny nickel iron covers made according to the invention with an iron content of 2 (t to 45% / u lead to equally good or better results With certain composite coatings there are shiny nickel deposits.

shiny nickel iron. those thinner than 0.0127 mm Jind. with an alloy content of about 20 to 45% iron results in much better results than an equivalent Cilanz-Niekclüberzug. when copper or brass underlayers are used. If in particular the iron content is 35% or more. the alloy coatings grip the copper or metal underlays stronger than shiny nickel. l) This effect delays penetration into the Cirundmetull.

The shiny nickel-iron covers also work good as a thin topcoat on semi-glossy, sulfur-free nickel coatings. The shiny one Nickel-iron coating is combined in such Coatings are particularly effective when coated with a non-continuous chrome coating such as that used in the IIS-PS 35 63 864 and 31 51 971-3 is described. passed over will. The micro-discontinuous C'hroni covers can be produced by thin nickel coatings which induce microporosity or microcracking in the chromium, or by using the Applies chrome coating from a specific solution, causing micro-cracked chrome to be deposited will.

Up to 50% of the nickel salts can be replaced by cobalt salts, so that a different corrosion »Ion behavior.

It has also been found that the current density of the iron-nickel bath can be extended if an additional brightener containing a sulfide and a sulfonate is used. Such a connection can contain up to 14 carbon atoms, preferably up to 6 carbon atoms, and can be represented by the formula I will be represented.

Formula I.

O ₃ SRSA

wherein

A denotes hydrogen, -Ri-SO ₃ -, -SR ₃ -SO, - or -R ₃ , in which R, R ₁ or R _{3 are} saturated alkylene, arylene or aralkyl groups and

R, an alkyl, an aryl, or an aralkyl group

mean.

The definition of “alkyl, aryl or araikyl groups” also includes the corresponding substituted groups which are substituted with alkyl groups having 1 to 4 carbon atoms, with halogen such as chlorine, bromine or fluorine or with a water-solubilizing group. The term "water-solubilizing group" means any polar group which will facilitate the solubilization of the molecule in the aqueous network. Preferred groups are hydroxyl, ethers such as alkoxy with up to and including 12 carbon atoms, polyoxyalkylenes such as polyoxyethylene up to and including 1000 repeating units or polyoxypropylene with up to and including 50 repeating units. Sulfonic acids. Sulfate. Nitro. Carboxylic acids or their alkyl esters with 1 to (i carbon atoms.

The compounds represented by the formula I. can be made as follows.

When Λ is hydrogen, i. H. a connection of formula II.

O ₁ -SR -SII

the compounds are produced by reacting a suI-tons with sodium sulfide (Na-S).
r> If A is - R, -SO-, ie compounds of the formula III.

Formula III
ι ».J ₁ SRSR ₁ -SO,

these compounds can be prepared by reacting a compound of the formula II with a sultone will.

s. If A is -SR ₃ -SO ₁ -, ie compounds of the formula IV,

Formula IV
■ ι »O ₁ S -RSSR, - SO-,

these compounds can be prepared by reacting a compound of the formula II with a mild oxidizing agent such as hydrogen peroxide .

When AR is ₁ , ie a compound of the formula V.

Formula V
w

O ₁ S -RSR.,

For example, these compounds can be prepared by reacting the sodium salt of a compound containing a mercapto group with a sultone.
Examples of compounds containing mercapto groups are alkyl mercapto compounds, ie compounds in which the alkyl group I contains up to 12 carbon atoms, preferably 1 to 6 carbon atoms, such as methyl mercaptan, propyl mercaptan, butyl mercaptan, hexyl mercaptan, octyl mercaptan, decyl mercaptan, dodecyl mercaptan and aryl mercapto compounds such as benzene mercaptan, Naphthyl mercapto or aralkyl mercaptan such as benzyl mercaptan, 2-phenylethyl mercaptan or 4-butyl mercaptan.

The group -SO ₃ - is intended to include the acid and all salts which are soluble in the bath, such as the alkali metal salts, for example the sodium or potassium salts.

The sultones which can be used in the above-described llniset- H ₁ C / ions are those of the fol

structures:

c ii - cHj — cH -

SO; O

I ₁ C- (CH,) CH-CH ₂ -CH,

I I

O-

-SO,

H ₁ C - (CI I,), - C H-CH ₂ -CH, O SO ₂

11, C- (CH-K-CH-CH-CH-CH,

I i

SO ₂ O

CH- CH, - CH, - CH- CH, CH,

H, CO SO ₂

CH, HC ₁ - (CH,) - CH-CH-CH-CH ₁

i I

co O

1I ₁ C (CH ₂ K-CH-CH ₂ -CH-CH ₁ SO O

H ₁ C- (CII,) CH-CH, -CH-CH ₁

ι ι

SO,-

-O

H ₁ C- (CHO ₁ - -CH- CII, - CH,

i j

O SO,

11, C- (CH ₂ I-CH-CH ₂ -CH ₂ -CH _:

j i

O- SO ₂

H ₁ C-CH-CH ₂ -CH-CH ₅

SO,-

-O

CH, -CH, -CH, -CIi, -CH, C-CH ₂ -CH-CH,
'H ₁ C SO ₃ O

CH ₂ -CH ₂ -CH ₂

SO,

CH ₃ -CH.-CII.-CII,
SO, O

h, c - cn - cn, - cn,

SO,-

I. O

CH,

H ₁ C- CC H-. - CH - CH,

I I

SO, O

H ₁ C-CH-CH-CH-CH-CH-CH,

I I

O SO-

CH,

so.

SO- - O

A. Y) X / O- .A
'ί! I -SO; Λ

SO,-

-O Λ / Λ,

It can be seen that the groups R, R ₁ and R _{2 are} the remaining parts of the reaction of a Sultan and the compounds mentioned above.

The organic sulfide according to the invention is in the nickel-iron bath in a concentration in the range from 0.001 to 0.020, preferably from 0.001 to 0.005 g / l. used.

Line suitable composition used in the present Invention can be used is as follows.

Miileriiil 23 33 069 14th 13th Preferred Group nil ionsbc rich Concentration Nickeisuliat 6 IU) iK-r -.- vh Nickel chloride 50 g / l Liisenfin sulfate 7 H ₂ O 40 to 300 g / l 100 g / l Complexing agent 60 to 250 g / l 15 g / l Boric acid 5 to 40 g / l 20 g / l average Cathode current density 10 to 100 g / l 60 g / l Anode current density 30 to 90 g / l temperature 7.2 to 4.5 AAIM ¹ pH 1.08 to 2.2 A / dno stir 60 to 71 C 3.4 to 4.2 Glossy fabric 2.5 to 5.5 with air or with a stick see above

Ks can also use surfactants as additives can be used in the bath, whereby one wünlchenswerte Results obtained that serve to prevent any scarring or granulation occurring in the case of particular Avoid situations that may arise.

It has been found that soluble iron anodes or nickel-iron alloy anodes can be used I was thrilled when large amounts of iron were introduced into the system. The vciii '.' Ratio of nickel to iron in the anode area should be kept at about 4: 1. Double (nickel and iron) anocles are preferred used, and the iron anodes should be insulated and connected to the anode bar via a device which has a high electrical resistance, such as a nickel-chromium wire »Which are controlled with a separate rheostat, by a total current from the iron anodes of S to 30%, preferably from 10 to 25%, of the total anode current maintain. Anode bags, filter bags, hoses and tank linings are in the generally used according to other bright nickel processes.

The following examples illustrate the invention.

example 1

A bath for a shiny iron-Mickel coating was formulated as follows:

50 g / l Nickel sulfate hexahydrate 100 g / l Nickel chloride hexahydrai 15 g / l Iron (II) sulfate heptahydrate 20 g / l Ammonium hydrogen citrate 60 g / l Boric acid pH 4.0 temperature 65.6 ° C stir Rod 4.5 g / l Saccharin 3.75 g / i Allyl sulfonate 200 mg / i Butir.'jio'i-a'h! Inoxid (Ye; hälinis Lf mole Ovid: 1 mole D; o !; 10 mg / l Quinaldin propane sultone.

Example 2

The procedure described in Example 1 was used, c but 7.5 to 75 g / l glycine instead of citrate, forming an insoluble complex. One received not an acceptable coating of nickel and iron.

Example 3

Another nickel-iron bath was formulated as follows:

75 g / l nickel sulfate hexahydrate

75 g / l nickel chloride hexahydrate

15 g / l iron (II) sulfate heptahydrate

40 g / l sodium gluconate

40 g / l boric acid

pi I 3.0

Temperature 65.6 ° C

Stirring air

2.5 g / l saccharin

6.0 g / l allyl sulfonate

50 mg / 1 glycerine ether of butynediol (ad-

duct from 1.8MoI ethylene cvii: 1 mol Diol)

50 mg / 1 sulfonated glycerol ether of butynediol (same as the adduct above with the exception that the product is sulfonated)

vi 15 mg / 1 adduct of 1.8 mol epichlorohydro-

inside: 1 mole of propargyl alcohol: the product is sulfonated

2.5 mg / 1 thiourea-S-acetic acid.

A test plate (J-shaped bent steel) was electroplated in this bath; you got a shiny, uniform nickel plating with excellent ductility and clean indentation surfaces.

The iron content of the deposit was 20 to 25%.

Example 4

A nickel-iron bath with a fine iron concentration was examined in a test facility in the laboratory. The following bath composition was used:

Rolled steel plates were coated at 4.8 A / m- and one e-hieit hoc!; glossy, ductile deposits, the 15 to 20% iron smhirUcr:

NiCl,

H, 0

42.fi g / l

100th year g / l

76.6 s / 1st

Ii

H ₃ BO ₃

Na-gluconal

Total iron

Saccharin

Allyl sulfonate

Glycerine ether of butynediol

(see example 3)

sulfonated glycerol ether

(see example 3)

Adduct of ethylene oxide and

Propargyl alcohol

pH

temperature

lfi

36.0 g / l

65.0 g / l 5.8 g / l 2.5 g / l 6.0 g / l 0.05 g / l

0.05 g / l 0.012 g / l

3.0 68 ° C

A steel plate (J type) was galvanized at 5.4 A / drrr; a completely shiny, leveled, very juctile coating with a partially omitted indentation area.

To the bath was added 0.002 g / l dithiodipropane sulfbnate, and another plate was electroplated. The resulting deposition was again complete on the whole shiny, leveled, and ductile, but this time the recessed areas were clean, covered, and shiny.

These deposits contained 38 to 47 percent iron.

Example 5
A bath was formulated as follows:

Total iron 3.11 g / l Fe ' ^: 2.83 g / l Fe * ' 0.28 g / l Allyl sulfonate 4.5 g / l Saccharin 3 g / l Butynediol-ethylene oxide adduct 200 mg / 1 (1.1.8 molar ratio) Quinaldin propane sultone 10 mg / 1 NiCI, 101.8 g / l NiSO ₄ 122.7 g / l Ni " 52.6 g / l Boric acid 59.1 g / l pH 4.0 temperature 65.6 ° C stir cathode or stick

A J-shaped plate was ^{electroplated at 4.3 A / dm 2} and a completely glossy deposit was obtained in the areas of high current density and a haze at a slightly lower current density.

By adding only 50 mg / 1 benzenesulfinate, the haze on the depression was completely removed. the Coatings contained 17.5% Fe.

Example 6

Two nickel-iron baths with the following composition were made:

NiCI, 6H, O
NiSO, 6H, ()
FeSO.,

75 g / l 75 g / l 15 g /!

HjBO, 40 g / l

Na gluconate 12.5 g / l

Na-citral 12.5 g / l

Saccharin 3.0 g / l

Allyl sulfonate 6.0 g / l

Adduct of butynediol and 0.06 g / l

Epichlorohydrin (1.2 mol hydrin: 1 mol diul), hydrolyzed
product

Adduct of butynediol and 0.06 g / l

Epichlorohydrin (1.2 mol hydrin: 1 mol diol), sulfonated
product

Adduct of propargyl alcohol and 0.02 g / l
Epichlorohydrin (1: 1 molar ratio),
sulfonated product

Dithiodipropane sulfonate 0.002 g / l Epichlorohydrin (1: 1 molar ratio), 0.002 g / l ι emperaiur
stir air sulfonated product 71.1 ° C NiCl, 6Η, 0 7 ^ς "/! Dithiodipropane sulfonate air NiSO ₄ 6 H, O 75 g / i temperature FeSO ₄ 7H ₂ O 15 g / l stir H, BO, 40 g / l Na gluconate 12.5 g / l NHj citrate 12.5 g / l Saccharin 3.0 g / l Allyl sulfonate 6.0 g / l Adduct of butynediol and 0.06 g / l Epichlorohydrin (1.2 mol Hy inside: I mole diol). hydrolyzed product Adduct of butynediol and 0.06 g / l Epichlorohydrin (1.2 moles Hy inside: 1 mol diol), sulfonated product Adduct of propargyl alcohol and 0.02 g / l

In each bath, hot plates were electroplated at 4.8 A / dm 'for 10 minutes. The results showed that both deposits were completely glossy and had clean surfaces, the Test plate A was leveled better than test plate B. Both plates showed excellent results Ductility

It can be seen from examples that two complexing agents can be used to achieve desirable results / u So it was found that the (iluconate-KompIcxicruiigsmiUel the inclination bcsit / i. After long flexrolysis times, insoluble material, such as a nickel salt / from a glucon: 7erset / ungsprmlukl. »U form. In order to continue to obtain desirable results, one can also use a Mixture, ms complexing mills. like from r'jiral and (ilutonat. use

Claims (5)

Patent claims: 1. Acidic aqueous bath for galvanic deposition of a shiny nickel-iron coating a corrosion-sensitive substrate with a ■> Content of nickel, iron and possibly cobalt ions, a bath-soluble nickel luster in the form a sulfo-oxygen compound, at least one bath-soluble complexing agent with at least one carboxyl and one hydroxyl group and optionally a buffer and / or a surface-active compound, characterized in that that the ratio of nickel and iron ions in the bath is 5 to 50: 1, that the bath is 0.5-10 g / l des Nickel gloss former contains that the complexing ü is a non-reducing aliphatic carboxylic acid with 1 -3 carboxyl groups, 2-8 carbon atoms and 1-6 hydroxyl groups and in one Amount of 10-100 g / l is present and that the ratio of the concentration of the complexing agent to which the iron ions in the bath is 30-50: 1 and the bath has a pH value of 2.5 to 5.5 2. Bath according to claim 1, characterized in that the iron ions in a total concentration in an amount in the range of 5 to 40 g / l, öerech- 2ϊ net as FeSO ₄ · 7 H ₂ O are present, that the nickel sulfate in an amount ranging from 40 to 300 g / l, calculated as nickel sulfate · 6H2O , is present and that the nickel chloride is present in an amount in the range from 80 to 250 g / l 3 bath according to claim 1 or 2, characterized in that there is also an acetylenic Contains nickel brighteners in an amount in the range from 10 to 500 mg / 1. 4. Bath according to one of claims 1 to 3, characterized in that there is also a quaternary heterocyclic nitrogen compound as a nickel brightener in an amount ranging from 1 to 50 mg / 1 contains. 5. Bath according to one of claims I to 4, characterized in that there is also a connection the formula