KR19990007076A - Electroplating of Low Stress Nickel - Google Patents

Abstract

Nickel and nickel alloys may be electroplated from an acidic aqueous solution containing nickel alkane sulfonic acid and a stress-reducing additive that imparts compressive stress to the electrodeposites. The electroplating bath is acidic with a pH of 0-5.

Description

Electroplating of Low Stress Nickel

This application claims priority of US Patent Application No. 60 / 050,140, filed June 18, 1997.

FIELD OF THE INVENTION The field of the present invention relates to baths for electroplating low stress nickel on conductive substrates and to methods of using such baths.

Many industries provide the substrates with corrosion resistant, decorative finishes and electroformed coatings by continuously or batch plating the substrates with nickel in an electroplating bath.

Nickel sulfamate baths are generally consumed when a low stress nickel coating, such as an electrical mold coating, is needed or when the nickel deposit may be subjected to external stress. Nickel sulfamate solutions have (a) better mechanical properties of coatings made with sulfamate than coatings formed from sulfate solutions compared to nickel sulfate solutions, (b) high-speed attachment from sulfamate solutions, and (c) The properties of the deposits are preferred because they are hardly affected by changes in pH and changes in current density. However, some care needs to be taken when nickel sulfamate baths are used.

Typical nickel sulfamate solutions contain nickel sulfamate (400-650 g / l), nickel chloride (5-20 g / l) and boric acid (30-40 g / l). The operating pH is 3.5 to 4.5 and the temperature can vary from 35 to 50 ° C. Soluble nickel anodes are used to supply fresh nickel that is plated to the cathode during electrolysis. The current density is 0.5 to 30 A / dm ² .

One of the problems with using nickel sulfamate baths is the solubility of sulfamate ions.

Sulfamate ions are dissolved in solutions that are neutral or slightly alkaline at elevated temperatures. However, due to the precipitation of nickel hydroxide, this solution is not used at pH above 5.

Hydrolysis of sulfamate ions can be a problem. Hydrolysis of sulfamate is generally characterized by the formation of ammonium ions and unsulfate or sulfate cations:

^{_{H 2 NSO 3 - + H 3}} O + ⇒ NH 4 + + HSO 4 -

Studies of the hydrolysis reaction of sulfamate have found that the rate increases at higher hydrogen ion concentrations (eg, lower pH). These researchers also found that sulfamate hydrolysis increased with increasing electrolyte temperature; Nickel sulfamate solutions are therefore typically operated at lower temperatures than Watts type nickel plating solutions.

Sulfamate ions also decompose at the anode, for example at insoluble anodes such as platinum and at positive nickel oxide electrodes. As the sulfamate decomposes, many intermediates are prepared, such as sulfites, dithionates, azobissulfonates and other unknown materials that can affect the quality of the electrodeposition coating.

It is desirable to provide a bath other than nickel sulfamate for electrodepositing nickel.

When selecting a nickel solution for electrodepositing the nickel layer, it is important to consider the internal stresses formed in the nickel coating. The stress in nickel electrodeposition is from -15,000 PSI (compression) to about +100,000 PSI (tensile). High tensile stresses lead to cracking of the nickel electrodeposition, especially when nickel is subjected to mechanical strain (stress and strain) or elevated temperatures. Nickel electric castings, such as those made from nickel sulfamate solutions, may be warped or resized when removing the substrate if the substrate is in a tensile stress state. High tensile stresses also lead to lower fatigue life of steel and aluminum alloys. The researchers found that when nickel was electrodeposited under compression, a 22% reduction in fatigue life for high-strength steels, but a 59% reduction in fatigue life under tensile stress. Similarly, aluminum alloys plated with nickel at tensile stress show a 55% reduction in fatigue life but only a 10% decrease when nickel is compressive stressed.

Typically, organic additives are added to the nickel solution to reduce the tensile stress of the electrodeposition. The composition and concentration of the stress reducing agent depends on the properties of the nickel electrolyte (eg nickel sulfate or nickel sulfamate). The effect of this organic stress reducer on the internal stress of nickel electrodeposition from the nickel sulfate solution was tested. Sulfur containing additives such as saccharin, naphthalene-1,5-disulfonic acid and naphthalene trisulfonic acid are effective as stress reducing agents. Their effects on internal stress in sulfur containing compounds and nickel coatings were also studied. Sodium benzene sulfonate, benzene sulfonamide and sulfanic acid reduce internal stress, but only benzene sulfonamide affects compressive stress. However, p-amino benzene sulfonamides produce stresses that become tensile stresses in nickel electrodepositions plated from sulfate solutions.

Kudryavtsev et al., Entitled Nickel Electrodeposition from Methansufonic Acid-Based Bath, Proceedings of American Electroplaters, Surface Finishing, pages 837-841 (1996), refer to Ni (CH _3). Electroplating Nickel from SO ₃ ) ₂ is compared with electroplating from a nickel sulfamate bath.

Kudjalfchev et al. (1) sulfamate baths are chemically unstable and (2) sulfamate begins to decompose at 60 ° C., but the bath operates at 45 to 60 ° C. and (3) the bath is free of other metal ions. To prevent deterioration of coating quality, deterioration of the efficiency of ductility and cathode currents, including those that are sensitive to impurities, the maximum Fe that can be present in the bath is 20 mg / L, the maximum Cu is 10 mg / L, and the maximum Zn is The disadvantages of sulfamate baths with 10 mg / L, maximum Pb of 2 mg / L and maximum Cr of 2 mg / L are described.

Kudlyafschev et al. Found that the compositions they tested ranged from Ni (CH ₃ SO ₃ ) ₂ 100 to 400 g / l; H ₃ BO ₃ 17 to 40g / ℓ; Saccharin 0.01-1.8 g / l; And 0.02 to 0.5 g of sodium lauryl sulfate; The electroplating process is pH 0.8 to 2.0; Temperature 30 to 60 ° C; And current density (CD) of 0.5 to 39 A / dm ² . However, there is a problem in electroplating using the composition described by Kudrajchev, et al. First, because sodium saccharin is extremely soluble in water but saccharic acid is not, saccharic acid begins to crystallize when the process pH is less than 2 and electrodeposits of saccharic acid are electrodeposited with electroplated nickel, producing an unacceptable coating. Can be. Secondly, Kudrajchevchev et al. Described that the tested Ni (CH ₃ SO ₃ ) ₂ compositions formed positive (tensile) internal stresses and did not form the desired negative (compressed) internal stresses.

Accordingly, it is an object of the present invention to obtain the advantages of avoiding these and other difficulties encountered in the art. These and other advantages are achieved in accordance with the present invention which provides methods and compositions of matter that substantially eliminate one or more of the limitations and disadvantages of the prior art and material compositions described in the art.

In order to achieve these and other advantages, the present invention allows the use of nickel alkanesulfonic acid in electroplating processes to produce low stress nickel coatings with compressive stresses, when specifically and extensively described according to the purposes of the present invention. It includes the composition of the substance.

One aspect of the invention relates to a composition of materials for making low stress electroplating nickel coatings. Such a composition is an aqueous acidic electroplating bath comprising nickel alkane sulfonic acid and a stress reducing additive that imparts compressive stress to the coating.

Another aspect of the invention relates to a method for producing an electroplated coating by electroplating a cathode conductive substrate in a coating bath having an anode inserted in the bath, wherein the bath is essentially a nickel alkane sulfide. Consisting of stress reducing additives that impart compressive stress to the acid and the coating and maintain the pH of the coating bath at about 0 to about 5; A method of maintaining a current density of a substrate at about 1 to about 100 A / dm ² is provided.

Another aspect of the invention is directed to a composition of material for freshly supplying a spent electroplating bath for producing a low stress electroplating nickel coating, wherein the spent bath initially comprises Ni (CH ₃ SO ₃ ) ₂ and the coating. It contains a stress reducing additive that imparts a compressive stress to the composition, the composition is a slurry containing nickel carbonate and aromatic sulfonic acid.

The methods and compositions of the present invention provide a good nickel coating on the conductive substrate.

The description set forth below represents additional features and advantages of the invention, and in part will be apparent from the description, or will be exemplified by the embodiments of the invention. Those skilled in the art will recognize the objects and advantages of the present invention obtained by compositions of the methods and materials specifically pointed out in the description and claims described herein.

Electroplating baths of the present invention generally comprise about 50 to 600 g / l nickel alkanesulfonic acid, preferably about 150 to 450 g / l; About 0.5 to 15 g / l, preferably 5 to 10 g / l, a stress reducing additive for imparting compressive stress to the electrodeposited coating; Optionally from about 0 to 100 g / l nickel halogen, preferably from 20 to 40 g / l and optionally from 0 to about 60 g / l buffer.

Nickel Alkanesulfonic Acid

Nickel alkane sulfonic acids include sulfonic acids of formula (R) (SO ₃ ) _x , wherein R and x are as defined below.

Nickel alkane sulfonate means that the compound is dissolved in water at about room temperature (about 20 ° C.) or at a lower temperature (about 10 to about 20 ° C.), preferably near or slightly below the operating temperature of the bath. It includes a water-soluble compound and is represented by the following formula (1):

Ni [(R) (SO ₃ ) _x ] _y

In Chemical Formula 1,

x is a value from 1 to about 3;

y is a value of 1 to 2 that can be 1 when x is greater than 1;

R is an alkyl group having 1 to about 15 carbon atoms, in particular 1 to about 7 carbon atoms, including straight and branched chain isomers, such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, pentyl and isopentyl, etc. to be. Also included are hydroxy substituted alkyl as alkyl is defined herein. Specific nickel salts in this regard are nickel methane sulfonate, nickel ethane sulfonate, nickel propane sulfonate, nickel isopropane sulfonate, nickel butane sulfonate, nickel isobutane sulfonate, nickel t-butane sulfonate, nickel pentane sulfonate And nickel isopentane sulfonate and the like, as well as hydroxy substituted compounds thereof. R is also from 4 to about carbon atoms including cyclic, heterocyclic hydrocarbon substituents such as cyclobutyl, cyclobutenyl, cyclohexyl, cyclohexenyl, cyclohexadienyl, cyclooctanyl, cyclooctadienyl 16, especially about 6 to about 14 cycloaliphatic, unsaturated cycloaliphatic and aromatic groups.

The compound is present in a sufficient amount such that the concentration of Ni ⁺⁺ is preferably 25 to 135 g / l, more preferably 50 to 100 g / l and most preferably about 80 g / l.

Nickel methane sulfonic acid —Ni (CH ₃ SO ₃ ) ₂ is preferred for use in the baths of the present invention.

Nickel alloy

In addition, the present invention may include an electrodeposited alloy of nickel as the nickel coating of the present invention, and may use an alkane sulphonate salt and a nickel alkane sulfonate of an alloy metal, and in Formula 1, the alloy metal may be substituted for Ni, y is a value of 1 equal to or less than the valence of the alloy metal and x has the value indicated above.

In addition, the alloy of nickel may be electrodeposited using alloying additives in the coating bath instead of or in addition to the sulfonate alloy compounds described herein. Any other group IB, IIB, IIIA, IVA, IVB, VA, VB, VIB, VIIB or VIIIB metal can be used as the alloying metal. Mixtures of alloy metals from group VIIIB and / or group IIB or mixtures of Cr or Mn are also particularly two-component when the alloy metal is present in the coating in an amount of about 0.1 to about 20% by weight, in particular about 5 to about 15% by weight. Or a three-component alloy. Examples of these include NiZn, NiCr, NiFe, NiP, NiMn, NiSn and NiW.

The alloy is prepared in a manner well known in the art by introducing an alloy metal into the coating bath as an anode or by adding an alloy metal salt to the coating bath.

Additives for stress reduction to impart compressive stress to coatings

Stress reducing additives that impart compressive stress to the electroplating coatings are in the bath of 0.5 to 15 g / l, preferably 2 to 15 g / l, more preferably 5 to 10 g / l, most preferably about 8 g / l. Present in concentration. Typically the concentration of the additive may range from 5-20% of the nickel ion concentration present in the bath.

Useful additives include those known to be useful in Watts baths and sulfamate baths. All are well known in the art and include aromatic sulfonic acids which may be a 6-membered ring or polynuclear ring having about 10 to about 14 carbon atoms in its aromatic group. Any position of 1 to about 3 sulfonate groups may be substituted in the aromatic ring. Examples include aminobenzene sulfonic acid, benzene sulfonic acid, benzene disulfonic acid, naphthylamine disulfonic acid, naphthalene monosulfonic acid, naphthalene disulfonic acid, naphthalene trisulfonic acid, naphthol monosulfonic acid and p-toluene sulfonic acid. .

Other useful stress reducing additives include benzene sulfamide, cysteine hydrogen chloride, saccharin (useful when the pH of the bath can be maintained above 2), p-toluene sulfonamide, thioacetamide, thiosemicarbazide and thiourea It includes.

Naphthalene trisulfonic acid, in particular 1,3,6-naphthalene trisulfonic acid, is preferred.

Nickel halide

If a soluble nickel anode is used in the process, preferably the bath contains a nickel halogen such as for example NiCl ₂ or NiBr ₂ . Nickel halide acid assists in dissolution of the soluble anode. The amount of nickel halogen present in the bath is about 0 to 100 g / l, preferably 20 to 40 g / l.

Other additives for bath

It is also within the scope of the present invention to control the bath by adding other ingredients known to those skilled in the art. Such other additives may be formulated to reduce surface tension and prevent bubbling of hydrogen gas, for example, from 0 to about 60 g / l of a buffer such as boric acid, preferably from 35 to 45 g / l and / or surfactants (eg Sodium lauryl sulfate) from 0 to about 2 ml / l, preferably about 1 ml / l.

pH

Electrodeposition according to the process of the invention is carried out at a pH of about 0 to about 5, preferably about 0.5 to about 4.5, most preferably about 1 to 4.

Current density

The compositions and methods of the present invention operate at current densities from about 1 A / dm ² to about 200 A / dm ² , preferably from about 2 A / dm ² to about 30 A / dm ² . Preferred current densities for high speed plating such as steel strips are from about 50 A / dm ² to about 100 A / dm ² .

Temperature

The process of the invention is carried out at approximately room temperature (20 ° C.) to about 80 ° C., preferably from about 30 ° C. to about 70 ° C., most preferably from about 40 ° C. to about 60 ° C.

Stirring

The solution may be agitated to prevent burning in the high current density region and even to control the temperature of the solution. Air stirring, mechanical stirring, pumping, cathode rods and other solution stirring means are all satisfactory. Moreover, it can operate without stirring a solution.

For high speed plating, such as in steel strips, the agitation of the bath preferably forms a flow rate of about 0.5 to 5 m / s.

Newly supplied composition

If the process uses an insoluble anode, it may ultimately be necessary to provide a fresh solution of the bath so that sufficient nickel is present in the bath to enable electroplating of low stress nickel. Compositions suitable for freshly supplying an electroplating bath containing spent nickel alkane sulfonic acid and stress reducing additives are intended to provide compressive stress to nickel carbonate (a) and electrodeposits that provide a fresh supply of nickel and increase the pH of the bath. It is a slurry containing the additive (b) for stress reduction of the initial bath used.

Typically, the slurry may contain 0.5 to 10 g / l, preferably 1.5 to 5 g / l, of a stress reducing additive per 1000 g / l of nickel carbonate present in the slurry. However, the amount of stress reducing additive may depend on the particular stress reducing additive used in the slurry. For example, when 1,3,6-naphthalene trisulfonic acid is a stress reducing additive, the amount thereof may be about 1 to 6 g / l, most preferably about 3 g / l per 1000 g / l of nickel carbonate.

The amount of slurry added to the bath may be based on the amp hour that the bath being consumed is exposed and may be sufficient to maintain the amount of nickel in the bath at the desired concentration by the electroplating machine.

anode

Anodes useful in the process of the invention include, for example, soluble anodes such as nickel foil, for example insoluble anodes such as platinum and precious metal oxides.

The insoluble (inactive) positive electrode used in the present invention is insoluble (inert) in the electrolyte solution and consists of a solid bipolar metal or metal compound, for example an oxide, wherein the metal is IVB, VB, VIB, VIIB, VIIIB and IB of the periodic table. The group or anode may be a metal or alloy thereof as described above, leading to, for example, cheaper basic metals from Group IVB, VB, VIB, VIIB, and Group VIIIB metals and their supporting materials, including their alloys (eg stainless steel). Include. Preferred anodic metal compounds are iridium dioxide (IrO ₂ ). Alloy metals of IrO ₂ are preferably VIB and VIIB metals such as chromium, molybdenum and nickel.

Insoluble anodes may be used to electrodeposit any galvanic metal in addition to nickel. Metals that can be electrodeposited are known to those skilled in the art and include zinc, copper, lead, chromium, magnesium, tin, molybdenum and alloys thereof.

Board (cathode)

Electroplating is performed in the manner described herein by electrolytically coating a conductive substrate using the composition of the present invention, wherein the substrate (cathode) comprises any electrically conductive substrate or polymer substrate, or a conductive material such as a metal or carbon substrate Insulation substrates coated with (eg, polymeric materials or ceramic substrates, such as synthetic polymer substrates) or any kind of known conductive substrate.

Despite describing examples of electroplating methods as performed on steel substrates, any conductive substrate may use polymers, plastics, pure metals, metal alloys and other iron alloy substrates or metals or IB, IIB, IIIA, IVA And alloys based on Group IVV, VA, VB, VIB, VIIB or VIIIIB metals and elements, which alloys of two or more metals and elements, in particular of two or three or four component metals and elements Combination.

fair

The coating proceeds by passing an electric current between the anode in the electric coating bath and the cathode in the bath for a sufficient time to electrodeposit the desired nickel coating on the cathode.

As indicated throughout the specification, the various numerical ranges describing the invention also specifically include concentration ranges of compounds, ratios of such compounds to other compounds, molecular weight, pH, current density, temperature, etc., as well as integer and / or fractionality. Any combination of lower and lower ranges of concentrations and higher and upper ranges shown herein, including values and ranges within these ranges, are included.

Example 1

A bath containing Ni (CH ₃ SO ₃ ) ₂ (300 g / l) and 1,3,6-naphthalene trisulfonic acid (7.5 g / l) was prepared. Nickel halogen or buffer is not added.

The bath is used to electrodeposit the nickel coating on the steel plate using gentle air agitation at 50 ° C. using a 1 L plating vessel. The anode is a piece of nickel foil. The average current density is about 4 A / dm ² . The pH of the bath starting the plating is 3.5 and 2.1 at the end of the plating.

Electrodeposition is carried out for 15 minutes to give a thickness of 7-10 μm of the coating. The coating is smooth and semi-bright. The stress in the coating is -6000 PSI (compression).

Example 2

Containing Ni (CH ₃ SO ₃ ) ₂ (300 g / l), 1,3,6-naphthalene trisulfonic acid (75 g / l), NiCl ₂ (40 g / l) and H ₃ BO ₃ (45 g / l) Prepare the bath

The bath is used to electrodeposit the nickel coating on the steel plate using gentle air agitation at 50 ° C. using a 1 L plating vessel. The anode is a piece of nickel foil. The average current density is about 4 A / dm ² . The pH of the bath starting the plating is 3.5 and at the end of the plating is 3.4.

Electrodeposition is carried out for 15 minutes to give a thickness of 9-12 μm of coating. The coating is smooth and semi gloss. The stress is -5200 PSI (compression).

Example 3

A bath containing Ni (CH ₃ SO ₃ ) ₂ (300 g / L), sodium saccharin (1 g / L), NiCl ₂ (40 g / L) and H ₃ BO ₃ (45 g / L) was prepared.

The bath is used to electrodeposit the nickel coating on the steel plate using gentle air agitation at 50 ° C. using a 1 L plating vessel. The anode is a piece of nickel foil. The average current density is about 4 A / dm ² . The pH of the bath starting the plating is 3.3 and at the end of the plating is 3.4.

Electrodeposition is carried out for 30 minutes to give a thickness of 19-23 μm of coating. The coating is smooth and semi gloss. The stress is -2000 PSI (compression).

Example 4

A bath containing Ni (CH ₃ SO ₃ ) ₂ (300 g / l) and 1,3,6-naphthalene trisulfonic acid (7.5 g / l) was prepared. The bath is used to electrodeposit the nickel coating on the steel plate using gentle air agitation at 50 ° C. using a 1 L plating vessel. The anode is an iridium oxide coated titanium piece. The average current density is about 4 A / dm ² . The pH of the bath starting the plating is 1.8 and at the end of the plating is 1.7.

Electrodeposition is carried out for 60 minutes to give a thickness of 40-45 μm of coating. The coating is smooth and semi gloss. The stress is -3200 PSI (compression).

Example 5

A bath containing Ni (CH ₃ SO ₃ ) ₂ (300 g / l) and 1,3,6-naphthalene trisulfonic acid (7.5 g / l) was prepared. The bath is used to deposit the nickel coating on the steel plate using gentle air agitation at 55 ° C. using a 1 L plating vessel. Two anodes, soluble nickel foil and iridium oxide coated titanium pieces are used. The average current density is about 5 A / dm ² . The pH of the bath starting the plating is 2.0 and 1.8 at the end of the plating.

Electrodeposition is carried out for 30 minutes to give a thickness of 18-22 μm of coating. The coating is smooth and semi gloss. The stress is -1500 PSI (compression).

Example 6

Nickel methanesulfonate solutions are prepared by dissolving 150 g / l NiCO ₃ in 70% MSA. After complete dissolution of the nickel carbonate, the solution is filtered to remove any remaining specific material. To this was added 30 g / l boric acid and 5 g / l naphthalenetrisulfonic acid. This solution is heated to 60 ° C. to dissolve the boric acid. Upon cooling to room temperature the pH is adjusted to 2.0 with 70% MSA.

A. The steel coupon is washed with an anode in NaOH 50 g / l and then rinsed with water. It is activated for 5 seconds at room temperature in 5% HCL. The steel is plated at 4 A / dm ² for 15 minutes. The plate is glossy and smooth. The cathode current efficiency is 89.3%.

B. Add 10 g / l of Al ₂ O ₃ (150mesh) to this solution and mix. The second plate is pretreated as described above and plated for 15 minutes. The plate is smooth and semi-gloss. The cathode efficiency is 90.2%. Scanning electron microscopy shows the co-deposition of aluminum oxide particles in the nickel matrix.

Example 7

Nickel methanesulfonate solutions are prepared by dissolving 150 g / l NiCO ₃ in 70% MSA. After complete dissolution of the nickel carbonate, the solution is filtered to remove any remaining specific material. To this was added 15 g / l nickel chloride, 30 g / l boric acid and 3 g / l naphthalenetrisulfonic acid. This solution is heated to 60 ° C. to dissolve the boric acid. Upon cooling to room temperature the pH is adjusted to 3.2 using 70% MSA.

A. The steel plate is pretreated as described above and plated in solution. The plate is glossy and smooth. Cathode current efficiency is 96%.

B. To this solution add ₂ g / l MoS ₂ molybdenum disulfide. Mix for 10 minutes. The steel plate is pretreated and plated as described above. The cathode efficiency is 94%. SEM analysis shows the presence of MoS ₂ particles.

C. Add ₂ g / l MoS ₂ to a fresh nickel solution. These particles are mixed in a nickel solution for 10 minutes. The steel plate is cleaned as described above and plated in this solution. SEM analysis shows the presence of MoS _{2 in} the nickel coating.

Example 8

A 5% aqueous solution of sulfamic acid is prepared and the pH is adjusted to 3.0. The oxidation of sulfamic acid is investigated using a three electrode electrochemical setup. The counter electrode is an IrO ₂ grid. The reference electrode is silver / silver chloride. The working electrode is iridium coated titanium. The potential of this system is scanned from -0.2V in the direction of the anode. Large oxide peaks appear at + 0.3V.

Prepare 5% MSA solution and adjust pH to 3.0 using sodium bicarbonate. The same three electrode system is used for this investigation. There is no oxidation peak at + 0.3V in this MSA solution.

Thus, an insoluble anode can be used in the nickel methanesulfonate electrolyte and no alteration by side products occurs. Insoluble anodes in sulfamic acid solutions can be used to induce destruction of the product at the anode.

Comparative Example 1

A bath containing Ni (CH ₃ SO ₃ ) ₂ (300 g / l) and sodium saccharin (1 g / l) was prepared. Nickel halogen is not used.

The bath is used to electrodeposit the nickel coating on the steel plate using gentle air agitation at 50 ° C. using a 1 L plating vessel. The anode is a piece of nickel foil. The average current density is about 4 A / dm ² . During plating white precipitates appear in the plating solution. It is saccharic acid that precipitates because of a drop in pH.

Electrodeposition is carried out for 30 minutes to give a thickness of 17-23 μm of coating. The coating is slightly rough and semi gloss. +4200 PSI (tensile).

Comparative Examples 2 to 5

Five coatings of nickel electroplated from a bath containing Ni (CH ₃ SO ₃ ) ₂ are compared. The effect of H ₃ BO ₃ , NiCl ₂ , pH, CD and NTS (1,3,6-naphthalene trisulfonic acid) on stress is investigated. All processes are operated at 60 ° C.

Summary of results

The stress in all electrodeposits in the absence of NTS is the tensile force. NTS is essential to ensure compressive stress.

Comparison swear 2 Comparison profane 3 Comparison lust 4 Comparative bath 5 of the present invention Comparative bath 6 of the present invention Ni (CH ₃ SO ₃ ) ₂ 300 g / ℓ 300 g / ℓ 300 g / ℓ 300 g / ℓ 300 g / ℓ NTS radish radish radish 7.5g / ℓ 7.5g / ℓ NiCl ₂ 45g / ℓ 45g / ℓ 45g / ℓ 45g / ℓ radish H ₃ BO ₃ radish radish 30 g / ℓ 30 g / ℓ radish pH 4.5 1.2 1.47 1.47 1.21 CD in process Stress of coating Stress of coating Stress of coating Stress of coating Stress of coating 4A / dm ² +17,344 +17,759 +20,115 -7,963 -7,543 8 A / dm ² +37,890 +16,947 +20,529 -7,445 -8,229 12 A / dm ² +30,282 +21,298 +19,996 -7,824 -8,465 20 A / dm ² +22,568 +25,078 +18,400 -9,335 -6,936 50 A / dm ² +19,263 +16,272 Combustion Combustion +380 slightly burning

Throughout the specification, the inventors of the present invention refer to various materials that are used in the present invention as based on a particular compound, and in fact contain these components, or these components include at least the basic components in these materials.

It will be apparent to those skilled in the art that various modifications and variations can be made to the compositions and methods of the present invention without departing from the spirit or scope of the invention. Such modifications and variations of the present invention are intended to be included as part of this invention, provided they are within the scope of the appended claims and their equivalents.

The present invention is electroplating nickel and nickel alloys from an acidic aqueous solution containing nickel alkane sulfonic acid and a stress reducing additive that imparts compressive stress to the electrodeposited product.

Claims (22)

Nickel alkanesulfonic acid (a), A stress reducing additive (b) for imparting compressive stress to the coating, Any nickel halogen (c) and A composition of matter for producing a low stress electrodeposited nickel coating, which is an acidic electroplating aqueous bath comprising any buffer (d). The amount of nickel alkanesulfonic acid is present in a concentration of about 50 to about 600 g / l, the stress reducing additive is present in an amount of about 0.5 to about 15 g / l and nickel halogen in an amount of 0 to about 100 g / l And a buffer is present in an amount from 0 to about 60 g / l. The amount of nickel alkanesulfonic acid is present in a concentration of about 150 to about 300 g / l, the stress reducing additive is present in an amount of about 5 to about 10 g / l and nickel halogen of 20 to about 40 g / l And the buffer is present in an amount of 35 to about 45 g / L. The composition of claim 1 wherein the additive for stress reduction is aromatic sulfonic acid. The composition of claim 1 wherein the nickel alkane sulfonic acid is nickel methane sulfonic acid and the stress reducing additive is naphthalene trisulfonic acid. The composition of claim 1 further comprising nickel halogen. The composition of claim 6 wherein the nickel halogen is NiCl ₂ . Essentially Nickel alkanesulfonic acid (a), A stress reducing additive (b) for imparting compressive stress to the coating, Any nickel halogen (c) and Electroplating the negative electrode conductive substrate in a bath of paint composition with positive electrode, consisting of any buffer (d), maintaining the paint composition at pH about 0 to about 5, and maintaining a current density on the substrate from about 1 to about 200 A / A method of making a low stress electrodeposited nickel coating comprising maintaining at dm ² . The method of claim 8, wherein the bath further comprises nickel halogen. The method of claim 8, wherein the pH is maintained at about 0.5 to about 2.0. The method of claim 8, wherein the substrate comprises a steel conduit. The method of claim 8, wherein the substrate comprises a steel wire. The method of claim 8, wherein the substrate comprises flat steel. The amount of nickel alkane sulfonic acid is present in a concentration of about 50 to about 600 g / l, the stress reducing additive is present in an amount of about 0.5 to about 15 g / l and nickel halogen in an amount of 0 to about 100 g / l And buffer is present in an amount from 0 to about 60 g / l. The amount of nickel alkanesulfonic acid is present in a concentration of about 150 to about 300 g / l, the stress reducing additive is present in an amount of about 5 to about 10 g / l and nickel halogen of 20 to about 40 g / l And buffer is present in an amount from 35 to about 45 g / l. The method of claim 8, wherein the nickel alkane sulfonic acid is nickel methane sulfonic acid and the stress reducing additive is naphthalene trisulfonic acid. The method of claim 8, wherein the nickel alkane sulfonic acid is nickel methane sulfonic acid and the stress reducing additive is sodium saccharin and the composition is maintained at pH about 2 to about 5. 10. A depleted electroplating bath containing Ni (CH ₃ SO ₃ ) ₂ and a stress reducing additive, wherein the bath is used for a low stress electrodeposited nickel coating and the composition is a slurry comprising nickel carbonate and a stress reducing additive in the initial bath. A composition of matter for freshly feeding it. 19. The composition of claim 18 wherein the slurry comprises 0.5 to 10 g / l per 1000 g / l of nickel carbonate for the stress reducing additive. The method of claim 18, wherein the stress reducing additive is an aromatic sulfonic acid. Insoluble anode, including immersing the galvanic metal on the substrate by immersing the anode and the substrate in an aqueous solution of a salt of a soluble alkanesulfonic acid or salt of an aromatic sulfonic acid of galvanic metal and passing current through the solution at a sufficient current density. A method of electroplating a galvanic metal coating on a conductive substrate in the presence of a. The method of claim 21, wherein the alkanesulfonic acid is methanesulfonic acid.