US3152975A

US3152975A - Electrodeposition of nickel

Info

Publication number: US3152975A
Application number: US87551A
Authority: US
Inventors: Kardos Otto; Jr William B Stoddard
Original assignee: Hanson Van Winkle Munning Co
Current assignee: Hanson Van Winkle Munning Co
Priority date: 1961-02-07
Filing date: 1961-02-07
Publication date: 1964-10-13
Anticipated expiration: 1981-10-13
Also published as: GB924864A

Description

1 United States Patent 3,152,975 ELECTRQDEPOSET 6N 0F NICKEL Otto Kardos, Red Bank, and William B. Stoddard, Jr.,

Matawan, Nl, assignors to Hanson-Van Winkle- Munning Company, a corporation of New Jersey No Drawing. Filed Feb. 7, 1961, Ser. No. 87,551 11 Claims. (Cl. 204-49) This invention relates toelectroplating and, more particularly, to electrodepositing nickel from an aqueous acidic nickel plating bath. The invention is based on the discovery that the isomeric vinylbenzenesulfonic acids and certain of their salts, when incorporated in a nickel plating bath. Particularly in conjunction with various other additives, are remarkably effective for promoting the formation of ductile electroplates which are much smoother than the basis metal plated in such a bath.

This ability of an electroplating bath to improve on the smoothness of the basis metal is known as leveling ability and can be used industrially to reduce or eliminate mechanical or electrochemical finishing of the base metal.

We have found that in all instances the use of one of the isomeric vinylbenzenesulfonic acids or their corresponding alkali metal, ammonium, magnesium or nickel salts in a nickel plating bath exerts a pronounced leveling effect on the electroplate formed during the plating operation. Accordingly, the invention provides an improved process for producing a nickel deposit substantially smoother than the basis metal to which it is applied which comprises electrodepositing nickel from an aqueous acidic solution of at least one nickel salt in which there is dissolved a substituted-styrene having a structure represented by the formula V r in which M is a cation substituent of the group consisting of hydrogen, alkali metals, ammonium, magnesium and nickel. Although any of the three isomeric vinylbenzenesulfonic acids may be used in a nickel plating bath in accordance with the invention, particularly satisfactory results have been obtained using the sodium salt of para isomer, p-vinylbenzenesulfonic acid.

By themselves, the isomeric vinylbenzenesulfonic acids and their salts, and in particular p-vinylbenzenesulphonic acid, are capable of promoting the formation of excellent bright nickel electrodeposits over the current density range of less than 10 to more than 100 amperes per square foot and of exerting a considerable leveling effect on the bath. When, however, a small quantity of p-vinylbenzenesulfonic acid or one of its above-mentioned salts is incorporated in the plating bath together with either a Class I sulfo-oxygen carrier brightener or a Class 11 secondary brightening compound, the brightness capacity of the bath is extended and the electrodeposit is bright over a very wide current density range with little diminution in the leveling effect exerted by this substituted-styrene on the bath.

Only relatively small quantities of p-vinylbenzenesulfonic acid or its salts are required in the plating bath, especially when used in conjunction with a Class I sulfooxygen carrier brightener or a Class II secondary brightener, for we have found that the p-vinylbenzenesulfonic acid and its salts exert a noticeable leveling efiect on the bath at concentrations as low as abdut 0.1 gram per liter. There appears to be no critical upper limit on the concentration of this substituted-styrene, but there is no particular advantage in using more than about 20 grams per liter, or even less. At concentrations over the range from about 0.1 to about 20 grams per liter, the level effect of p-vinylbenzenesulfonic acid (or its salts) in nickel plating baths has been found to be especially pro- 3,152,975 Patented Oct. 13, 1964 "ice nounced when the bath is operated at temperatures rangmg from about C. to about 85 C. and at a pH from 3.0 to 5.0, with or without agitation of the bath.

The compounds listed in Table I are examples of the sulfo-oxygen compounds which, when used in combination with p-vinylbenzenesulfonic acid and its above-mentioned salts promote the formation of bright and ductile nickel deposits which are substantially smoother than the base metal to which they are applied. These sulfo-oxygen compounds may be used over a wide range of concentrations A to 80 grams per liter), but preferably are used in an amount in the range from about 1 to about 20 grams per liter.

TABLE I Organic Sulfa-Oxygen Compounds (1) Unsaturated aliphatic sulfonic acids, and alkali metal, ammonium, magnesium, and nickel salts thereof:

Sodium vinyl sulfonate, H C=CHSO Na Sodium allyl sulfonate, H C=CHCH SO Na (2) Mononuclear aromatic sulfonic acids, and alkali metal, ammomum, magnesium, and nickel salts thereof:

Benzene monosulfonic acid, C H SO H Sodium benzene monosultonate, C H SO Na Nickel benzene monosulfonate, (C l-l SO Ni Sodium p-toluene monosulfonate, CI-l C H SO Na p-Chlorobenzene sulfonic acid, ClC H SO l-l 'Sodium p-chlorobenzene sulfonate, ClC H SO Na Sodium p-bromobenzene sulfonate, BrC -H SO Na 1,2-dichlorobenzene sulfonic acid, Cl C H SO l-l 1,2- or 2,5-dichlorobenzene sulfonates, sodium salt,

Cl C H SO Na v m-Benzene disulfonic acid, C H (SO H) Sodium m-benzene disulfonate, C H (SO Na) Nickel m-benzene disulfonate, C H (SO Ni o-Sulfobenzoic acid monoamrnonium salt,

H0OCC H SO NH lamino-2,5-benzene disulfonic acid, H NC H (SO H) o-Aminobenzene sulfonic acid, H NC H SO H (3) Mononuclear aromatic sulfinic acids, and alkali metal, ammonium, magnesium, and nickel salts thereof:

Sodium benzene sulfinate, C H SO Na Sodium p-toluene sulfinate, CH C H SO Na (4) Mononuclear aromatic sulfonamides and sulfonimides:

Benzene sulfonamide, C H SO NH p-Toluene sulfonamide, CH C H SO NH o-Sulfobenzoic imide,

CGHlCONI'ISOg Benzyl sulfonamide, C l-l CI-l SO NH Benzene sulfhydroxamic acid, C H SO NHOH NJJ-dimethyLp-toluene sulfonamidc,

CH C H SO N CH 2 N,N-dicarboxyethyl benzene sulfonamide,

C6H5SO'2N 2 (5) Binuclear aromatic sulfonic acids, and akali metal, ammonium, magnesium, and nickel salts thereof:

3 Sodium Z-naphthol-3,6-disulfonate, HOC H (SO Na) 1-naphthylamine-3,6,8-trisulfonic acid,

(6) Heterocyclic sulfonic acids, and alkali metal, ammonium, magnesium, and nickel salts thereof: Thiophene sulfonic acid, C H S-SO' H Sodium thiophene sulfonate, C H S-SO Na For the most part, only free sulfonic acids are listed in Table I. However, the alkali metal, ammonium, magnesium, and nickel salts are in all cases the full equivalent of the acids, and may be used in their place in carrying out the process of this invention.

Even brighter electrodeposits are obtained when p-vinylbenzenesulfonic acid (or its salts) is employed in the plating bath in conjunction with a Water-soluble acetylenic compound, particularly the oxygen-containing acetylenic compounds. For example, plating baths which contain sodium p-vinylbenzenesulfonate together with a water-soluble acetylenic brightener additive have a much wider brightening capacity and more often yield bright electrodeposits than baths which contain either additive alone. Our experiments indicate that any water-soluble acetylenic compound effectively cooperates to some degree with p-vinylbenzenesulfonic acid or its salts in enhancing the leveling and uniformity of brightness of the nickel electroplate, though some acetylenic compounds are more effective than others.

The common structural feature of these water-soluble acetylenic compounds is the preesnce of a highly nucleophilic triple bond which is neither sterically hindered nor impeded in approaching the cathode. Only relatively small quantities of the acetylenic compounds are required in the bath when used in conjunction with p-vinylbenzenesulfonic acid or any of its above-mentioned salts. Concentrations as low as 0.1 millimol per liter, or even less, are effective in some cases, though in general it is preferable to employ at least 1 rnillimol per liter. In general, there is no advantage in employing more than about 25 millimols per liter of the acetylenic brighteners, and in most plating baths the full benefit of their presence is achieved with concentrations in the range from 1 to millimols per liter.

in which each of R and R are substituents of the group consisting of hydrogen, alkyl, alkenyl, alkynyl, and hydroxy-substituted and alkoxy-substituted alkyl, alkenyl, and alkynyl groups, R is a substituent of the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, hydroxy-substituted and alkoxy-substituted alkenyl and alkynyl groups, and substituted-alkyl groups having the structural configuration in which each of R and R are substituents of the group consisting of hydrogen, alkyl, alkenyl, alkynyl, and hydroxy-substituted and alkoxy-substituted alkyl, alkenyl, and alkynyl groups, and each of R and R, are substituents of the group consisting of hydroxy, alkoxy, carboxysubstituted alkoxy, formoxy, alkanoxy, halogen and polyoxy groups. Where R is a substituted-alkyl group having the above-illustrated structural configuration, then the acetylenic compound is termed an a, x'-disubstituted acetylenic compound, since both carbon atoms vicinal to the same acetylenic bond contain either the same or a diiferent functional group. The compounds listed in Table II are examples of various tit-substituted acetylenic compounds which may be used successfully in plating baths containing p-vinylbenzenesulfonic acid or one of its salts. As indicated previously, these acetylenic compounds are preferably used in concentrations from about 1 to about 25 millimols per liter.

TABLE II a-Substituted Acetylenic Compounds l z Ra O E 0- 9-31 Compound R1 Ra R: R

2-Butyne-lA-diol -H H CHzOH 0H 1,4-Di-(fl-hydroxyethoxy)-2-butyne H CH O CH; CHzOH O CHzCHzO H 1,4-Diacetoxy-2-butyne H 0 Hi 0 lOI 0 H3 0 (I? C H;

3-Butyne-1,2-dio1 CH2OH -H H O H B-Methyl-l-butyne- CHa OH3 H -OH 3-Methyl-l-pentyn-3-ol. CzH5 CH -11 OH 2-Propyn-l-ol E I -H H OH 2,5-Dimethyl-1-oeten-3-yn-5-ol C3H GH; (3113 --OH 3-Methyl-l-nonyn-3-ol CH13 OH; H OH 2,4-Hexadiyne-l,6-diol H CECCH:O H OH 1Methoxy-2-propyne H H 0 CH3 3-Methoxy-3-methyl-4,6-heptadiyne O 1115 CH -GECH O 0 H 3-Ethoxy-3,5,7-trimethyll-octyne... O H CH H O CzHu 1-Formoxy-2-propyne H H '-H 0 $311 1-Acet0xy-2-propyne -11 -H H O C CH3 3-Methy1-1-nonyn-3-yl acetate -0 H1a -CH3 H O (H CH3 Among the most satisfactory acetylenic brightening agents are those prepared by reacting either an a-liydroxy or an a,a-dihydroxy acetylenic compound, such as those listed in Table H, with either ethylene oxide or epichiorohydrin. These adducts readily dissolve in acidic nickel plating baths and are unusually effective in such baths both in promoting the formation of bright and ductile electrodeposits over wide current density ranges and in exerting a pronounced leveling effect on the bath during the plating operation. Two such adducts which are notably effective when used in conjunction with p-vinylbenzenesulfonic acid or any of its above-mentioned salts,

particularly with sodium p-vinylbenzenesulfonate, are the a,ot-di-(polyoxy)-2-butynes obtained upon the reaction of 1 2-butyne-l,4-diol with ethylene oxide and with epichlorohydrin.

2-butyne-l,4-diol reacts with ethylene oxide in the presence of a base to form a l,4-di-(hydroxypolyethoxy)- Z-butyne which is structural characterized by the formula II brighteners as unsaturated N-oxides (e.g., pyridine N-oxide); aromatic phosphinic acids (e.g., phenylphosphinic acid); wamino-N-heterocyclic compounds (e.g., a-amino pyridines and oz-pyrimidines); bis-pyridyls (e.g.,

2,2'-dipyridyl); olefinic alcohols (e.g., 2-bu'tene-1,4-diol);,

the condensation products of tetraethylene-pentamine with acryonitrile, methyl sulfate, epichlorohydrin, benzenesulfonyl chloride, or dimethylchloracetal; pyridinium halides (e.g., ethylene-bis-pyridinium bromide, dimethylene-bis- 41.25 grams per liter of boric acid. After adjusting the pH of the bath to 4.5 with sulfuric acid, the, electrodeposits were formed in an open vessel on roughened steel cathodes, using vigorous air agitation, a bath temperature of 60 C., and an average current density of 60 amperes per square foot. In several of these examples, the ditference in roughness values of the electroplated and the unplated (roughened) steel panels was measured to determine whether the additive or combination of additives employed exerted a leveling effect onrthe bath during the plating operation.

EXAMPLE I Using a nickel plating solution having the basic composition described above and to which had been added 0.5 gram per liter of sodium p-vinylbenzenesulfonate, nickel was electrodeposited on a roughened steel panel over a period of 30 minutes. Under these conditions, the resultant electrodeposit was uniformly bright. The difierence between roughness values between the electroplated and unplated (roughened) steel panel was 86 per: cent, indicating that sodium p-vinyl-benzenesulfonate (which exists as the free acid in the solution) exerted a pronounced leveling eflect on the bath during the plating operation.

- EXAMPLE II a To the basic Watts plating solution described above was added 0.5 gram per li-ter'of sodium p-vinylbenzenesulfonate and 0.1 gram per liter of 2-butyne-l,4-diol, and nickel was electrodeposited on a roughened steel panel,

' using conditions which were identical to those described pyridinium chloride, and nitropyridinium pyrazole chloride); various azo compounds, such as mono, di-, and riarninoazo-benzenes; halogenated carbonyls, such as chloral hydrate, bromal hydrate, and butylchloral hydrate; coumarin compounds; alkylated quinolinium halides (egi, benzyl methyl quinolinium chloride); polyalkylene amines; and amino polyaryl methanes.

The following examples are illustrative of the effectiveness with which p-vinylbenzenesulfonic acid and its abovementioned salts may be used in nickel electroplating baths in accordance with the invention. In each of these examples, the basic plating bath employed was an aqueous solution containing 300 grams per liter of nickel sulfate, 45 grams per liter of nickel chloride (hexahydrate), and

in Example I. The resultant electrodeposit was brilliant in appearance, the increase in the brilliance of the deposit produced by the addition of 2-butyne-1,4-diol to the bath being easily discernable.

i EXAMPLE III Nickel was electrodeposited under the same conditions as those employed in Example II, with the sole difference being that 0.1 gram per liter of sodium 1,4-dihydroxy-2- 'butene-2-sulfonate (the reaction product of equimolar quantities of 2-butyne-l,4-diol and sodium bisulfite) was also added to the bath. The resultant electrodeposit was brilliant in appearance and substantially smoother than the roughened steel panel to which it was applied, and was not alfected when the bath was contaminated with copper and Zinc impurities. When 2 grams per liter of sodium fluoborate was added to this bath, the electrodeposit remained unaffected even when the bath was contaminated with iron. 7

EXAMPLE IV Using the basing plating bath having thecomposition 3 given above and to which had been added 4 grams per i liter of sodium benzenesulfonate, nickel was electrode-' posited on a roughened steel panel for a period of 30 minutes at a bath temperature of 60 C. and a current density of 60 amperes per square foot. There was no dilference Upon the addition of 1.2 grams per liter ofsodium p vinylbenzenesulfonate to this bath, the leveling effect 7 exerted by the bath was increased to 65 percent, the resultant electrodeposit being uniformly bright in appearance.

The general principle illustrated in each of the foregoing examples, that p-vinylbenzenesulfonic acid exerts a pronounced leveling effect on nickel plating baths when used alone or in combination with various other additives, was repeatedly and consistently verified in many tests using a large number of Class I carrier brighteners or Class II secondary brighteners.

Although the examples have illustrated the use of sodium p-vinylbenzenesulfonate in the standard Watts nickel electroplating bath, which is prepared by dissolving nickel sulfate, nickel chloride, and boric acid in water, similar advantages are also attained when p-vinylbenzenesulfonic acid or its above-mentioned salts are dissolved in other types of aqueous acidic nickel electroplating baths. For example, p-vinylbenzenesulfonic acid and its salts are beneficial when used in straight nickel sulfate baths, in straight nickel chloride baths, and in various other m'ckel plating baths based on using nickel formate, nickel sulfamate, or nickel fluoroborate as the nickel salt which is dissolved in an aqueous acidic solvent, or in nickel plating baths containing cobalt salts. Consequently, the invention is applicable to electrodeposition from any aqueous acidic solution of one or more nickel salts.

We claim:

1. A process for producing a nickel deposit substantially smoother than the basis metal to which it is applied which comprises electrodepos-iting nickel from an aqueous acidic solution of at least one nickel salt in which there is dissolved from about 0.1 to about grams per liter of a substituted-styrene having a structure represented by the formula in which M is a cation substituent of the group consisting of hydrogen, alkali metals, ammonium, magnesium, and

nickel. A

2. A process for producing a nickel deposit substantially smoother than the basis metal to which it is applied which comprises electrodepositing nickel from an aqueous acidic solution of at least one nickel salt in which there is dissolved from about 0.1 to about 20 grams per liter of a substituted-styrene of the group consisting of p-vinylbenzenesulfonic acid and the alkali metal, magnesium, ammonium, and nickel salts thereof.

3. A process for producing a nickel deposit substantially smoother than the basis metal to which it is applied which comprises electrodepositing nickel from an aqueous acidic solution of at least one nickel salt in which there is dissolved from about 0.1 to about 20 grams per liter of a substituted-styrene of the group consisting of pvinylbenzenesulfonic acid and the alkali metal, magnesium, ammonium, and nickel salts thereof, and from about /1 to about 80 grams per liter of a water-soluble sulfooxygen compound of the group consisting of unsaturated aliphatic sulfonic acids, mononuclear and binuclear aromatic sulfonic acids, mononuclear aromatic sulfinic acids, the alkali metal, magnesium, ammonium, and nickel salts of said acids, and mononuclear aromatic sulfonamides and sulfonirnides.

4. A process for producing a nickel deposit substantially smoother than the basis metal to which it is applied which comprises electrodepositing nickel from an aqueous acidic solution of at least one nickel salt in which there is dissolved from about 0.1 to about 20 grams per liter of a substituted-styrene of the group consisting of p-vinylbenzenesulfonic acid and the alkali metal, magnesium, ammonium, and nickel salts thereof, and from about 0.1 to about millimols per liter of a water-soluble acetylenic compound.

lenic compound having a structure represented by the formula R2 R CEC-( 3-R1 in which each of R and R are substituents of the group consisting of hydrogen, alkyl, alkenyl, alkynyl, and hydroxy-substituted and alkoxy-substituted alkyl, alkenyl, and alkynyl groups, R is a substituent of the group consisting of hydrogen, halogen, alkyl, aikenyl, alkynyl, hydroxy-substituted and alkoxy-substituted alkenyl and alkynyl groups, and substituted-alkyl groups having the structural configuration in which each of R and R are substituents of the group consisting of hydrogen, alkyl, alkenyl, alkynyl, and hydroxy-substituted and alkoxy-substituted alkyl, alkenyl, and alkynyl groups, and each of R, and R, are substituents of the group consisting of hydroxy, alkoxy, carboxy-substituted alkoxy, formoxy, alkanoxy, halogen and polyoxy groups.

6. A process for producing a nickel deposit substantially smoother than the basis metal to which it is applied which comprises electrodepositing nickel from an aqueous acidic solution of at least one nickel salt in which there is dissolved from about 0.1 to about 20 grams per liter of a substituted-styrene of the group consisting of p-vinylbenzenesulfonic acid and the alkali metal, magnesium, ammonium, and nickel salts thereof, and from about 0.1 to about 3 grams per liter of 2-butyne-1,4-diol.

7. A process for producing a nickel deposit substantially smoother than the basis metal to which it is applied which comprises electrodepositing nickel from an aqueous acidic solution of at least one nickel salt in which there is dissolved from about 0.1 to about 20 grams per liter of a substituted-styrene of the group consisting of p-vinylbenzenesulfonic acid and the alkali metal, magnesium, ammonium, and nickel salts thereof, and from about 0.1 to about 3 grams per liter of a 1,4-di-(hydroxyethylpolyethoxy)-2-butyne having the structural formula .p-vinylbenzenesulfonic acid and the alkali metal, magnesium, ammonium, and nickel salts thereof, and from about 0.01 to about 2 grams per liter of a bisulfite addition product having a structure represented by the formula in which M is a cation substituent of the group consisting of hydrogen, alkali metals, ammonium, magnesium, and

nickel. 7

'9. A process for producing a nickel deposit substan tially smoother than the basis metal to which it is applied which comprises electrodeposi-ting nickel from an aqueous acidic solution of at least one nickel salt in which there is dissolved from about 0.1 to about 20 grams per liter of a substituted-styreneof the group consisting of p-vinylbenzenesulfonic acid and the alkali metals, magnesium, ammonium, and nickel salts thereof, from about A to about 80 grams per liter of a water-soluble sulfooxygen compound of the group consisting of unsaturated aliphatic sulfonic acids, mononuclear and binuclear aromatic sulfonic acids, mononuclear aromatic sulfinic acids, the alkali metal, magnesium, ammonium, and nickel salts of said acids, and mononuclear aromatic sulfonamides and sulfonimides, and from about 0.1 to about 25 millimols per liter of a water-soluble acetylenic compound.

10. A process for producing a nickel deposit substantially smoother than the basis metal to which it is applied which comprises electrodepositing nickel from an aqueous acidic solution of at least one nickel salt in which there is dissolved from about :1 to about 20 grams per liter of a substituted-styrene of the group consisting of p-vinylbenzenesulfonic acid and the alkali metal, magnesium, ammonium, and nickel salts thereof, from about A to about 80 grams per liter of a water-soluble sulfooxygen compound of the group consisting of unsaturated aliphatic sulfonic acids, mononuclear and binuclear aromatic sulfonic acids, mononuclear aromatic sulfinic acids, the alkali metal, magnesium, ammonium, and nickel salts of said acids, and mononuclear aromatic, sulfonamides and sulfonimides, from about 0.1 to about 25 millimols per liter of a water-soluble acetylenic compound, and from about 0.01 to about 2 grams per liter of a bisulfite addition product having a structure represented by the formula HOOHPCH=C CHQOH in which M is a cation substituent of the group consisting of hydrogen, alkali metals, ammonium, magnesium, and nickel.

11. In the process of electroplating nickel from an acid aqueous solution of a nickel salt, the step comprising adding to said solution at least about 0.5 gram per liter of a compound selected from the group consisting of para vinyl benzene sulfonic acid and salts thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,455,555 Brown Dec. 7, 1948 2,466,677 Brown Apr. 12, 1949 2,523,190 Brown Sept. 19, 1950 2,712,522 Kardos et al. July 5, 1955 FOREIGN PATENTS 1,141,135 France Mar. 11, 1957 1,231,332 France Apr. 11, 1960 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3 l52,975 October 13 1964 Otto Kardos et a1.

It is hereby certified that error-appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line l4 for "bath, Particularly" read bath particularly line 45 for "p-vinylbenzenesulphonic" read p-vinylbenzenesulfonic line 7O for "level" read leveling column 3, line 29 for "preesnce" read presence column 5 line 35, for "structural" read structurally column 6, line 67, for "basing" read basic column 7, line 24 for "fluoroborate" read fluoborate Signed and sealed this 30th day of March 1965c (SEAL) Attest:

ERNEST W. SWIDER I EDWARD J. BRENNER Attcsting Officer Commissioner of Patents

Claims

1. A PROCESS FOR PRODUCING A NICKEL DEPOSIT SUBSTANTIALLY SMOOTHER THAN THE BASIS METAL TO WHICH IT IS APPLIED WHICH COMPRISES ELECTRODEPOSITING NICKEL FROM AN AQUEOUS ACIDIC SOLUTION OF AT LEAST ONE NICKEL SALT IN WHICH THERE OF A SUBSTITUTED-STYRENE HAVING A STRUCTURE REPRESENTED BY THE FORMULA