US3922209A

US3922209A - Electrode position of alloys of nickel, cobalt or nickel and cobalt with iron and electrolytes therefor

Info

Publication number: US3922209A
Application number: US498947A
Authority: US
Inventors: Frank Passal
Original assignee: M&T Chemicals Inc
Current assignee: Arkema Inc
Priority date: 1974-08-20
Filing date: 1974-08-20
Publication date: 1975-11-25
Anticipated expiration: 1992-11-25
Also published as: IT1033839B; NL7509898A; CA1058553A; JPS5166238A; JPS599637B2; SE7509245L; ES440326A1; ZA755278B; AU8407875A; BR7505302A; SE416825B; GB1464483A; FR2282488A1; CS187487B2; DE2537065A1; FR2282488B1; DE2537065C2

Abstract

WHEREIN M is a cation having a valence of 1-2; k is an integer 1-2 corresponding to the valence of M; and R is hydrogen or a monovalent aliphatic group of 1-16 carbon atoms; and 3. AN HYDROXY CARBOXYLATE COMPLEXING COMPOUND OR A POLYOL COMPLEXING COMPOUND SELECTED FROM THE GROUP CONSISTING OF MANNITOL, SORBITOL AND DULCITOL; AND 4. AN IODIDE OF A BATH COMPATIBLE CATION OR A COMPOUND PROVIDING AN IODIDE ANION WHEN PLATING COBALT-CONTAINING ALLOYS; FOR A TIME PERIOD SUFFICIENT TO FORM A SOUND METAL ELECTROPLATE UPON SAID CATHODE SURFACE.
In accordance with certain of its aspects, this invention relates to a process for the preparation of an electrodeposit which contains iron and at least one metal selected from the group consisting of nickel and cobalt which comprises passing current from an anode to a cathode through an aqueous plating solution containing an iron compound and at least one member selected from the group consisting of cobalt compounds and nickel compounds providing cobalt or nickel ions for electrodepositing alloys of iron with cobalt and/or nickel and containing in combination an effective amount of: 1. AT LEAST ONE MEMBER SELECTED FROM THE GROUP OF COOPERATING ADDITIVES CONSISTING OF: A. PRIMARY BRIGHTENER B. SECONDARY BRIGHTENER C. SECONDARY AUXILIARY BRIGHTENER D. ANTI-PITTING AGENT; AND 2. AN ORGANIC HYDROXY-SULFONATE COMPOUND OF THE FORMULA:

Description

United States Patent 1191 Passal 1451 Nov. 25, 1975 ELECTRODE POSITION OF ALLOYS OF NICKEL, COBALT OR NICKEL AND COBALT WITH IRON AND ELECTROLYTES THEREFOR [75] Inventor: Frank Passal, Detroit, Mich.

[731 Assignee: M & T Chemicals Inc., Greenwich,

Conn.

22 Filed Aug. 20, 1974 211 Appl.No.:498,947

[52] US. Cl 204/43 T [51] Int. Cl. C25D 3/56 [58] Field of Search 204/43 T, 43 N, 43 P, 48, 204/49 [56] References Cited UNITED STATES PATENTS 3,697,391 10/1972 Passal....v 204/43 T 3,804,726 4/1974 Passal 204/43 T 3,806,429 4/1974 Clauss et al. 204/43 T X Primary Examiner-G. L. Kaplan Attorney, Agent, or Firm-Kenneth G. Wheeless; Robert P. Auber [57] ABSTRACT In accordance with certain of its aspects, this invention relates to a process for the preparation of an electrodeposit which contains iron and at least one metal selected from the group consisting of nickel and cobalt which comprises passing current from an anode to a cathode through an aqueous plating solution containing an iron compound and at least one member selected from the group consisting of cobalt compounds and nickel compounds providing cobalt or nickel ions for electrodepositing alloys of iron with cobalt and/or nickel and containing in combination an effective amount of:

1. at least one member selected from the group of cooperating additives consisting of: a. primary brightener b.-secondary brightener c. secondary auxiliary brightener d. anti-pitting agent; and 2. an organic hydroxy-sulfonate compound of the formula:

25 Claims, N0 Drawings ELECTRODE POSITION OF ALLOYS OF NICKEL, COBALT OR NICKEL AND COBALT WITH IRON AND ELECTROLYTES THEREFOR This invention relates to improved processes and compositions for the electrodeposition of semi-bright or bright iron alloys with nickel or cobalt or nickel and cobalt. More particularly, this invention relates to the use of a new additive to improve the plating of ironcontaining alloys of nickel, cobalt and nickel-cobalt.

Because of the much lower cost of iron and its salts as contrasted to that of nickel and cobalt and their salts it would be highly desirable to electrodeposit alloys of nickel or cobalt or nickel and cobalt with iron containing an appreciable iron content thereby reducing metal and salt costs.

DETAILED DESCRIPTION In accordance with certain of its aspects, this invention relates to a process for the preparation of an iron alloy electrodeposit which contains in addition to iron, nickel or cobalt or nickel and cobalt which comprises passing current from an anode to a cathode through an aqueous plating solution containing at least one iron compound and nickel or cobalt or nickel and cobalt compounds to provide nickel, cobalt and iron ions for electrodepositing alloys of nickel or cobalt or nickel and cobalt with iron.

The baths contain an effective amount of at least one member selected from the group consisting of:

a. primary brightener b. secondary brightener c. secondary auxiliary brightener; and

d. anti-pitting agent; and an organic hydroxy-sulfonate compound of the formula:

wherein M is a cation having a valence of 1-2; k is an integer 1-2 corresponding to the valence of M; and R is hydrogen or a monovalent aliphatic group of 116 carbon atoms; and

an hydroxy carboxylate complexing compound or a polyol complexing compound selected from the group consisting of mannitol, sorbitol and dulcitol; and

an iodide ofa bath compatible cation or a compound providing an iodide anion when plating cobalt-containing alloys; for a time period sufficient to form a sound metal electroplate upon said cathode surface.

For bright, well-leveled alloy plating primary brighteners such as diethoxylated 2 butyne-l,4-diol or dipropoxylated 2 butyne-l ,4-diol may be used in cooperation with a sulfo-oxygen secondary brightener, preferably saccharin, a secondary auxiliary brightener and an anti-pitter. If full brightness and leveling are not desired a fairly lustrous deposit with fair leveling may be obtained using as a primary brightener a nitrogen heterocyclic compound such as N-allyl quinolinium bromide at a concentration of about 5 to mg/l in cooperation 2 with a sulfo-oxygen secondary brightener, a secondary auxiliary brightener and an anti-pitter.

The substrates on which the nickel-iron, cobalt-iron or nickel-cobalt-iron containing electrodeposits of this invention may be applied may be metal or metal alloys such as are commonly electrodeposited and used in the art of electroplating such as nickel, cobalt, nickelcobalt, copper, tin, brass, etc. Other typical substrate basis metals from which articles to be plated are manufactured may include ferrous metals such as steel; copper; alloys of copper such as brass, bronze, etc.; zinc, particularly in the form of zinc-base die castings; all of which may bear plates of other metals, such as copper, etc. Basis metal substrates may have a variety of surface finishes depending on the final appearance desired, which in turn depends on such factors as luster, brilliance, leveling, thickness, etc. of the nickel-iron, cobalt-iron and nickel-cobalt-iron containing electroplate applied on such substrates.

The term primary brightener as used herein is meant to include plating additive compounds such as reaction products of epoxides with alpha-hydroxy acetylenic alcohols such as diethoxylated 2 butyne-l ,4-diol or dipropoxylated 2 butyne-l,4-diol, other acetylenics, N-heterocyclics, active sulfur compounds, dye-stuffs, etc. Specific examples of such plating additives are:

l,4-di-(B-hydroxyethoxy)-2-butyne (or diethoxylated 2 butyne-l,4, diol) l,4-di-(,B-hydroxy-y-chloropropoxy)-2-butyne 1,4-di-(B-y-epoxypropoxy )-2-butyne l,4-di-(B-hydroxy-y-butenoxy)-2-butyne l,4-di-( 2'-hydroxy-4-oxa-6'-heptenoxy)-2-butyne N- l ,2-dichloropropenyl pyridinium chloride 2,4,6-trimethyl N-propargyl pyridinium bromide N-allyl quinaldinium bromide N-allyl quinolinium bromide 2-butyne-1,4-diol propargyl alcohol 2-methyl-3-butyn-2-ol thiodiproprionitrile thiourea phenosafranin fuchsin When used alone or in combination, a primary brightener may produce no visual effect on the electrodeposit, or may produce semi-lustrous, fine-grained deposits. However, best results are obtained when primary brighteners are used with either a secondary brightener, a secondary auxiliary brightener, or both in order to provide optimum deposit luster, rate of brightening, leveling, bright plate current density range, low current density coverage, etc.

The term secondary brightener as used herein is meant to include aromatic sulfonates, sulfonamides, sulfonimides, sulfinates, etc. Specific examples of such plating additives are:

. saccharin trisodium 1,3,6-naphthalene trisulfonate sodium benzene monosulfonate dibenzene sulfonimide sodium benzene monosulfinate 3 Such plating additive compounds, which may be used singly or in suitable combinations, have one or more of the following functions:

1. To obtain semi-lustrous deposits or to produce substantial grain-refinement over the usual dull, matte, grainy, non-reflective deposits from additivefree baths.

2. To act as ductilizing agents when used in combination with other additives such as primary brighteners.

3. To control internal stress of deposits, generally by making the stress desirably compressive.

4. To introduce controlled sulfur contents into the electrodeposits to desirably affect chemical reactivity, potential differences in complete coating systems, etc. thereby decreasing corrosion, better protecting the basis metal from corrosion, etc.

The term secondary auxiliary brightener as used herein is meant to include aliphatic or aromatic-aliphatic olefinically or acetylenically unsaturated sulfonates, sulfonamides, or sulfonimides, etc. Specific examples of such plating additives are:

1. sodium allyl sulfonate 2. sodium-3-chloro-2-butene-l-sulfonate 3. sodium B-styrene sulfonate 4. sodium propargyl sulfonate 5 monoallyl sulfamide CH=CH 6. diallyl sulfamide 7. allyl sulfonamide Such compounds, which may be used singly (usual) or in combination have all of the functions given for the secondary brighteners and in addition may have one or more of the following functions:

1 They may act to prevent or minimize pitting (probably acting as hydrogen acceptors).

2. They may cooperate with one or more secondary brighteners and one or more primary brighteners to give much better rates of brightening and leveling than it would be possible to attain with any one or any two compounds selected from all three of the classes:

1. primary brightener;

2. secondary brightener; and

3. secondary auxiliary brightener used either alone or in combination.

3. They may condition the cathode surface by catalytic poisoning, etc. so that the rates of consumption of cooperating additives (usually of the primary brightener type) may be substantially reduced, making for better economy of operation and control.

Among the secondary auxiliary brighteners one may also include ions or compounds of certain metals and metalloids such as zinc, cadmium, selenium, etc. which, although they are not generally used at present, have been used to augment deposit luster, etc. Other cooperating additives of organic nature which may be useful are the hydroxy sulfonate compounds of US. Pat. No. 3,697,391 i.e. typically, sodium formaldehyde bisulfite, the function of which is to make baths more tolerant to primary brightener concentrations, to increase toler- 4 ance toward metallic impurities such as zinc, etc., and, in this invention, to make the bath more tolerant to the complexing agent used and its concentration and also to the content of iron in the bath.

The term anti-pitting agent as used herein is an organic material (different from and in addition to the secondary auxiliary brightener) which has surfactant properties and which functions to prevent or minimize gas pitting. An anti-pitting agent may also function to make the baths more compatible with contaminants such as oil, grease, etc. by their emulsifying, dispersing, solubilizing, etc. action on such contaminants and thereby promote attaining of sounder deposits. Antipitting agents are optional additives which may or may not be used in combination with one or more members selected from the group consisting of a primary brightener, a secondary brightener, and a secondary auxiliary brightener. Of the four classes of organic surfactants i.e., anionic, cationic, nonionic or amphoteric, the type commonly used for the electrodeposition of Ni, Co, Fe, or alloys thereof and for functioning as anti-pitters is the anionic class. The anionic class individual members commonly used may be exemplified by the following:

sodium lauryl sulfate sodium lauryl ether sulfate sodium di-alkylsulfosuccinates sodium 2-ethylhexyl sulfate Typical nickel-iron-containing, cobalt-iron-containing, and nickel-cobalt-iron-containing bath compositions which may be used in combination with effective amounts of about 0.0050.2 grams per liter of the primary brightener, with about 1.0-30 grams per liter of the secondary brightener, with about 05-10 grams per liter of the secondary auxiliary brightener, and with about 0.05-1 gram per liter of anti-pitting agent, described herein, are summarized below. Combinations of primary brighteners and of secondary brighteners may also be used with the total concentration of members of each class coming within the typical concentration limits stated.

The hydroxy-sulfonate additive compounds of the invention may be prepared according to the following general reaction:

wherein M is a cation having a valence of 1-2; preferably M is an alkali metal or alkaline earth metal cation or ammonium; k is an integer l-2 corresponding to the valence of M; and R is hydrogen or a monovalent aliphatic group of l-l6 carbon atoms.

Typical nickel-containing, cobalt-containing, and nickelcobalt-containing bath compositions also containing iron which may be used in combination with effective amounts of about 0.5-5 g/l of the hydroxy-sulfonate additive compounds and effective amounts of about 0.00SO.2 g/l of the primary brighteners, with about l.030 g/l of the secondary brightener, with about O.5l0 g/l of the secondary auxiliary brightener, and with about 0.05l g/l of anti-pitting agent, described herein are summarized below. Boric acid should be present in an amount of from 15 grams per liter to 60 grams per liter.

Mannitol, sorbitol and dulcitol are optical isomers having the following formula: HOCH,(CHOH ,CH,0H

Mannitol, sorbitol, and dulcitol are used in single or combined concentration of grams per liter to 60 grams per liter. Their function in nickel, cobalt and iron alloys thereof plating baths have been disclosed in U.S. Pat. No. 3,804,726.

The aqueous bath compositions for electrodeposition of cobalt with iron or nickel and iron alloys may contain effective amounts of iodide from widely varying sources. Ionic iodide compounds have been found to be most preferred since the addition of such compounds has been found to be convenient and inexpensive. Any water-soluble iodide having a bath-compatible cation associated therewith may be employed in amounts sufficient to provide enhanced cobalt-containing electro: deposits as compared to cobalt-containing electrode posits which may be obtainedvin the absence of iodide ion. Typical iodide compounds include the alkali metal iodides, alkaline earth iodides, other inorganic watersoluble metal iodides, as well as organic or other suitable compounds which may provide ionizable iodide ions on addition to the bath.

Examples of such iodide compounds include sodium iodide, potassium iodide, cesium iodide, lithium iodide, ammonium iodide, calcium iodide, magnesium iodide, nickel iodide, cobaltous iodide, etc. Materials which are converted to iodide in the cobalt-containing electroplating bath or during the electrodeposition process may also be employed. In particular, iodine may be added (such as in the form ofa solution in methanol) to the aqueous cobalt-containing bath composition to provide effective amounts of iodide anions by interaction with bath constituents such as cobaltous ions according to the invention herein. Organic compounds which provide ionizable iodide ions may also be employed, but the use of such compounds is generally not preferred unless the organic moiety contributes some added effect which may be desirable for a particular cobalt or cobalt-alloy electroplating process.

Any effective amount of iodide may be employed. By an effective amount as used herein is meant an amount of iodide which is sufficient to provide improved cobalt-containing electrodeposits from a cobalt-containing electroplating bath composition as compared to an identical cobalt-electroplating bath composition which is essentially free of iodide ions. In typical bath compositions which contain cobalt ions it has been found that at least about 0.1 g/l of iodide (measured as iodide, I, ion) has been found to be sufficient to obtain improved cobalt deposits and at least 0.1 g/l has been found to give excellent results. An iodide ion concentration of 0.1-5 g/l will generally be found sufficient. Higher amounts of iodide may be used, but in general-the use of excessive amounts of iodide does not produce further enhancement of the cobalt-containing electrodeposit and may only serve to increase costs.

Typical aqueous nickel-containing electroplating baths (which may be used in combination with effective amounts of cooperating additives) include the following wherein all concentrations are in grams per liter (g/l) unless otherwise indicated.

Salts to make up the bath are of the types generally used for nickel and cobalt plating i.e. the sulfates and chlorides, usually combinations thereof. Ferrous iron 6 may be added as Ferrous Sulfate or Ferrous Chloride, or Ferrous Sulfamate, preferably the sulfate which is easily available at low cost and good degree of purity (as FeSO -7H O).

TABLE I AQUEOUS NICKEL-CONTAINING ELECTROPLATING BATHS Component Minimum Maximum Preferred nickel sulfate 200 500 300 nickel chloride 30 45 ferrous sulfate 5 80 40 boric acid 35 55 45 pH (electrometric) 3 5 4 A typical sulfamate-type nickel plating bath which may be used in practice of this invention may include the following components:

A typical chloride-free sulfate-type nickel plating bath which may be used in practice of this invention may include the following components:

TABLE III Component Minimum Maximum Preferred nickel sulfate 300 500 400 ferrous sulfate 5 60 45 boric acid 35 55 45 sorbitol, mannitol, l0 60 40 or dulcitol pH (electrometric) 2.5 4 3-3.5

A typical chloride-free sulfamate-type nickel plating bath which may be used in practice of this invention may include the following components:

TABLE IV Component Minimum Maximum Preferred nickel sulfamate 300 400 350 ferrous Sulfamate 5 6O 45 boric acid 35 55 45 sorbitol, mannitol, I0 60 40 or dulcitol pH (electrometric) 2.5 4

It will be apparent that the above baths may contain compounds in amounts falling outside the preferred minimum and maximum set forth, but most satisfactory and economical operation may normally 'be effected when the compounds are present in the baths in the amounts indicated. A particular advantage of the chloride-free baths of Table III and IV, supra, is that the deposits obtained may be substantially free of tensile stress and may permit high speed plating involving the use of high speed anodes. v

The following is an aqueous cobalt-nickel-iron-containing electroplating bath in which the combination of effective amounts of one or more cooperating additives according to this invention will result in beneficial effects.

TABLE v AQUEOUS COBALT-NICKEL-IRON-CONTAINING ELECTROPLATING BATH (All concentrations in g/l unless otherwise noted) Maximum Minimum Preferred Cobalt-Nickel Alloy Bath NiSO. 7H O 400 200 300 C050 7H O 225 l5 80 NiCl 6H O 75 l5 60 H 80 5O 37 45 FeSO 7H,O 60 5 45 Sorbitol, Mannitol, or 60 10 4O Dulcitol Typical cobalt-iron plating baths are the following:

The pH of all of the foregoing illustrative aqueous iron-nickel-containing, cobalt-iron-containing and nickel-cobalt-iron-containing compositions may be maintained during plating at pH values of2.0 to 4.5 and preferably from 3.0 to 3.5. During bath operation, the pH may normally tend to rise and may be adjusted with acids such as hydrochloric acid or sulfuric acid, etc.

Operating temperature ranges for the above baths may be about 30 to 70C. with temperatures within the range of 45 to 65C. preferred.

Agitation of the above baths during plating may consist of solution pumping, moving cathode rod, air agitation or combinations thereof.

Anodes used in the above baths may consist of the particular single metals being plated at the cathode such as iron and nickel, for plating nickel-iron, cobalt and iron, for plating cobalt-iron, or nickel, cobalt, and iron, for plating nickel-cobalt-iron alloys. The anodes may consist of the separate metals involved suitably suspended in the bath as bars, strips or as small chunks in titanium baskets. In such cases the ratio of the separate metal anodes areas is adjusted to correspond to the particular cathode alloy composition desired. For plating binary or ternary alloys one may also use as anodes alloys of the metals involved in such a percent weight ratio of the separate metals as to correspond to the percent weight ratio of the same metals in the cathode alloy deposits desired. These two types of anode systems will generally result in a fairly constant bath metal ion concentration for the respective metals. If with fixed metal ratio alloy anodes there does occur some bath metal ion imbalance, occasional adjustments may be made by adding the appropriate corrective concentration of the individual metal salts. All anodes or anode baskets are usually suitably covered with cloth or plastic bags of desired porosity to minimize introduction into the bath of metal particles, anode slime, etc. which may migrate to the cathode either mechanically or electrophoretically to give roughness in cathode deposits.

The following examples are submitted for the purpose of illustration only and are not to be construed as limiting the scope of the invention in any way.

Hull Cell tests were run under conditions described as follows and the deposits were examined along a line 2.54 cm from and parallel to the bottom edge of the Hull Cell panel.

A polished brass panel was scribed with a horizontal single pass of 2/0 grit emery to give a band width of about 1 cm. at a distance of about 2.5 cm. from the bottom of the panel. After cleaning the panel, including the use of a thin cyanide copper strike to assure excellent physical and chemical cleanliness, it was plated in a 267 ml. Hull Cell, at a 2 ampere cell current for 10 minutes, at a temperature of 50C. and using magnetic stirring.

A Watts Nickel bath was prepared having the following makeup composition:

nickel sulfate-300 g/l nickel chloride60 g/l boric acid-45 g/l The bath was given a high pH nickel carbonate treatment to precipitate heavy metal impurities, treated with 6 grams per liter of activated carbon and filtered after overnight digestion at 60C.

EXAMPLE I 250 ml. Watts Nickel 4 g/l Sodium Saccharinate 2.3 g/] Sodium Allyl Sulfonate 0.05 g/l Diethoxylated Butynediol 40 g/l FeSO .7H O (equivalent to 8.0 g/l Fe) 10 g/l Sodium Tartrate Dihydrate pH adjusted to 4.0

electrometric Thin, iridescent, non-uniform hazy deposit with poor leveling from 0 to about 1.8 asd-brilliant and well-leveled from 1.8 asd to high current density edge (about 12 asd). On adding 1 g/l Sodium Formaldehyde Bisulfite brilliant, well leveled deposit from O to [2 asd with excellent ductility and low current density coverage. On increasing the FeSO .7H O content to 60 g/l an excellent deposit was still obtained with no noticeable change in appearance or physical properties.

EXAMPLE II Same bath composition as for Example I except [0 g/l dl-Malic Acid as the hydroxy-carboxylate compound used.

Thin, uniformly hazy, poorly leveled deposit from 0 to about 2.2 asd iridescent, non-uniform, milky from 2.2 asd to about 5.0 asdbrilliant, well-leveled from 5 asd to high current density edge. On adding 1 g/l Sodium Formaldehyde Bisulfite brilliant, well leveled deposit from 0 to 12 asd. On increasing the FeSO .7H O content to 60 g/l a slightly hazy area about 1 cm. wide and 2.5 cm. long, eliptical in shape, appeared at the bottom low current density corner of the panel but the appearance and physical properties of the remainder of the deposit remained unchanged.

EXAMPLE III Same bath composition as for Example I except that 10 g/l Sodium Citrate Dihydrate was the hydroxy-carboxylate compound used.

Thin, very hazy, poorly leveled deposit between and 3.0 asd iridescent, non-uniform, milky from 3.0 to about 4.5 asd brilliant and well-leveled from 4.5 asd to high current density edge. On adding 1 g/l Sodium Formaldehyde Bisulfite a brilliant, well-leveled, ductile deposit from 0 to 12 asd with excellent low current density coverage. On increasing the FeSO .7I-I O content to 60 g/l, a small non-uniform, iridescent milky area in the lower high current density end of the panel and a slight haze from 0 to about 0.2 asd were obtained remainder of panel unchanged in appearance. On increasing the Sodium Formaldehyde Bisulfite to 2 g/l the high current density defect was eliminated but the very low current density haze persisted the remainder of the panel was unchanged in appearance.

EXAMPLE IV Same bath composition as for Example I except that g/l Sodium Glycolate was the hydroxy-carboxylate used.

Thin, hazy, poorly leveled deposit from 0 to about 2.2 asd brilliant and well-leveled from 2.2 to 12 asd. On adding 1 g/l Sodium Formaldehyde Bisulfite a brilliant, well-leveled, ductile deposit from 0 to 12 asd with excellent low current density coverage. On increasing the FeSO .7H O to 60 g/l a thin hazy band from 0 to about 0.05 asd was obtained the remainder of the panel unchanged in appearance.

EXAMPLE V Same bath composition as for Example I except that 10 g/l Sodium Boroglucoheptonate was the hydroxycarboxylate used.

Thin hazy deposit from 0 to 1.4 asd non-uniformly dull with some iridescence from 1.4 to about 5.0 asd brilliant well leveled from 5.0 asd to high current density edge. On adding 2 g/l of Erythorbic (Isoascorbic) Acid and readjusting pH to 4.0 thin, poorly leveled, hazy deposit from 0 to about 1.1 asd dull, iridescent from 1.1 to 4.0 asd, bright with fair leveling from 4.0 asd to high current density edge. On adding 2 g/l Sodium Formaldehyde Bisulfite bright deposit from 0 to 12 asd with only fair leveling.

COBALT IRON PLATING CO ANODE USED A Cobalt Watts type solution was prepared having the following composition:

cobalt sulfate300 g/l cobalt chloride60 g/l boric acid45 g/l After make-up the bath was given a high pH Cobalt Carbonate-activated carbon purification treatment and filtered after digestion overnight at 60C.

EXAMPLE VI 250 ml. of above stock solution 40 ml/l of 70% by wt. Sorbitol solution 80 g/l FeSO .7l-I O pH adjusted to 3.6.

Deposit lustrous from 0 to about 2.0 asd iridescent milky from about 2 asd to 2.5 asd milky from 2.5 to 11 asd non-uniformly dull from 11 to 12 asd. On

adding 4 g/l Sodium Saccharinate bare (no deposit) from 0 to about 0.1 asd lustrous from 0.1 asd to 2.4

asd dull white from 2.4 asd to 3.0 asd satiny milky from 3 asd to 12 asd and brittle. On adding further 1 g/l Kl (over a nickel strike) the deposit was generally milky from 0 to about 5.0 asd, and smutty, dull and badly pitted from 5 asd to high current density edge. On adding 2.3 g/l Sodium Allyl Sulfonate deposit lustrous from 0 to about 1.5 asd, and very dark, nonuniform and very brittle from 1.5 asd to high current density edge. The deposit was so poor that a primary brightener was not added since from experience such a brightener, if anything, will make the deposit worse unless one can start with a fairly uniformly hazy, glossy, ductile deposit.

EXAMPLE VII 250 ml. above stock solution 4 g/l Ascorbic Acid pH adjusted to 4.3

Lustrous deposit from 0 to about 0.8 asd dull gray, brittle from 0.8 asd to high current density edge. On adding 4 g/l Sodium Saccharinate the entire deposit dull with a dark brownish cast. On further adding 20 g/l FeSO .7H O the deposit bare along low current density edge, lustrous up to about 0.15 asd smeary, off-color and covered with micro-mounds from 0.15 asd to high current density edge. On increasing the FeSO .7l-l O to 40 g/l the deposit glossy semi-bright from 0 to about 0.2 asd non-uniform thin satiny white up to about 3.0 asd partially lustrous from 3 asd to high current density edge.

Based on the previous two Examples the plating of a sound Co-Fe alloy did not appear promising until the following tests.

EXAMPLE VIII 250 m1. above stock solution 40 g/l FeSO .7H O

2 g/l Erythorbic Acid 4 g/l Sodium Saccharinate 2.3 g/l Sodium Allyl Sulfonate pI-I adjusted to 4.0

Non-uniformly milky, brittle deposit from 0 to 12 asd. On adding 2 g/l Sodium Formaldehyde Bisulfite bright, poorly leveled deposit from 0 to about 5.0 asd yellowish to dark and very brittle from 5 asd to high current density edge. On adding 20 g/l Sorbitol and readjusting pH to 4.0 deposit lustrous with scattered haze and ductile from 0 to about 8 asd dull gray, grainy, brittle from 8 asd to high current density edge. On further adding 50 mg/l Diethoxylated Butynediol deposit bright with poor leveling from 0 to about 1.8 asd non-uniformly very milky, iridescent from 1.8 asd to high current density edge. On further adding 1 g/l KI brilliant poorly leveled deposit from 0 to about 2 mm. from high current density dull grainy 2 mm. width band along high current density edge. On increasing the Cobalt Chloride content from 60 to g/l brilliant fairly well-leveled, ductile deposit from 0 to high current density edge. A satisfactory bath composition to give a very good, commercially acceptable deposit was then:

Cobalt Sulfate 300 g/l Cobalt Chloride 120 gll Boric Acid 45 g/l Sorbitol 20 g/l Erythorbic Acid 2 g/l -continued Sodium Formaldehyde Bisulfite 1 g/l Potassium Iodide 1 g/l Sodium Saccharinate 4 g/l Sodium Allyl Sulfonate 2.3 g/l Ferrous Sulfate 40 g/l Diethoxylated Butynediol 50 mg/l It was evident from the test sequence that Erythorbic Acid, Sodium Formaldehyde Bisulfite, Potassium Iodide and Sorbitol synergistically interacted with 1, 2 and 2 auxiliary brighteners to give an excellent deposit; increasing the Cobalt Chloride content increased the limiting current density. After the addition of K1 all the deposits of this Example were made over a thin nickel strike.

EXAMPLE IX A bath having the following composition was prepared and purified by activated carbon treatment.

cobalt chloride200 g/l cobalt-sulfate200 g/l boric acid30 g/l To 250 ml. of the above bath there were added the equivalents of the following:

Sorbitol 40 g/l FeSO .7H O 40 g/l Sodium Saccharinate 4 g/l Sodium Allyl Sulfonate 2.3 g/l Potassium Iodide 1 g/l pH adjusted to 4.0

The deposit was non-uniformly very milky from to about 3.5 asd and lustrous from 3.5 asd to the high current density edge. The leveling was poor. On adding 1 g/l Sodium Formaldehyde Bisulfite the deposit was lustrous from 0 to 12 asd with poor leveling and a very slight rather uniform haze the ductility was excellent. On further adding 50 mg/l Diethoxylated Butynediol a brilliant, ductile, fairly well leveled deposit was obtained from 0 to 12 asd and the low current density coverage was fairly good. All the deposits of this Example were'made over a thin nickel strike deposit.

EXAMPLE X The bath of Example I was then subjected to a 4-liter life test using conditions as follows:

Plating cell liter rectangular cross-section (13 cm X 15 cm) made of Pyrex.

Solution volume 4 liters to give a solution depth, in

absence of anode, of about 20.5 cm.

Temperature 60C. (maintained by immersing cell in a thermostatically controlled water bath).

Agitation moving cathode rod.

Anode single bagged titanium basket containing SD nickel squares.

Cathode brass strip (2.54 cm x 20.3 cm x 0.071 cm) buffed and polished on one side and immersed to a depth of about 17.8 cm horizontal bend 2.54 cm from bottom and the next 2.54 cm bent to give an internal angle on the polished side of cathode of about 45 polished side facing anode at an approximate distance of 10.2 cm and scribed vertically in center with a 1 cm wide band of a single pass of 2/0 grit emery paper scratches.

Cell current 5.0 amperes.

Time solution electrolyzed about 7 hours per day occasional cathodes plated for 30 minutes to evaluate deposit leveling, uniformity, ductility, luster (overall and in low current density recessed area).

Filtration occasional batch.

Additions the pH was periodically adjusted when necessary with dilute sulfuric acid to within a range of 3.0 to 3.5 electrometric; periodic replenishment additions of the primary brightener and the secondary auxiliary brightener were made to maintain deposit luster and leveling. The ferrous iron content of the bath was maintained with separate nickel and Armco iron anode systems in bagged titanium baskets with occasional corrective additions of ferrous sulfate, based on analysis for ferrous iron, to maintain the nickel and ferrous iron contents of the bath fairly constant.

Plating tests were first run on the bath of Example I also containing 0.125 g/l Sodium di-n-hexyl-sulfosuccinate and made up initially without Sodium Formaldehyde Bisulfite, using electrolytic nickel squares as anode in a bagged titanium anode basket, adding iron as 40 g/l FeSO .7I-I O and using air agitation at a temperature of C. The first two deposits showed a definite haze in the recess of the bent cathode and at the solution line and this was completely eliminated after adding 1 g/l Sodium Formaldehyde Bisulfite to subsequently give brilliant, ductile, quite well leveled deposits overall. After several hundred ampere-hours of electrolysis, during which period suitable additive replenishments (mainly 1 brightener and FeSO .7I-I O) were made to give a bright, leveled alloy containing about 35% Fe on the average, a basic iron precipitate formed to some extent on the anode bag, some of which also became suspended in the solution resulting in an orange-peel defect on shelf areas. On adding 2 g/l Erythorbic Acid the basic ferric salt was reduced and solubilized and excellent performance was again attained.

The deposits had the following general characteristics:

Brightness very good and easy to maintain.

Ductility excellent.

Internal Stress low tensile.

Leveling fairly good.

Hydrogen Embrittlement by Chromium Plating very low.

Pitting Tendency very low.

Smoothness of Deposits excellent.

EXAMPLE XI Using the finally evolved bath composition of Example VIII a 4 liter life test was run on depositing a brilliant, leveled cobalt-iron alloy using essentially the conditions of Example X except that the anode metal was cobalt. Optimumly using moving cathode rod agitation to attain best deposit luster in extreme low cathode current density areas, bright, well-leveled, ductile cobaltiron deposits having tensile stress were obtained consistently. It was found, however, over an electrolysis period of several hundred ampere-hours that the average cobalt content was about 94% while the average iron content was only about 6 percent. This relatively low iron content would not seem to make the decorative plating of bright, leveled cobalt-iron alloy economically attractive because of the preponderant alloy metal content would be of the relatively expensive cobalt. In con- .13 trast, in nickel-iron alloy plating substantially higher iron contents may be obtained, say, up to almost 50 percent, which together with the lower price for nickel than for cobalt makes nickel-iron alloy plating much more economically attractive for decorative commercial purpose. In cobalt-iron plating the metal cobalt acts as a metal considerably more noble than iron and thereby plates in preference to iron at the cathode even at relatively high bath iron metal contents. However applications may be found for the utilization of a high cobalt-low iron sound alloy deposit to take advantage of possibly special magnetic, metallurgical, physical etc. properties. t I 1 Although this invention has been illustratedby reference to specific embodiments, modifications thereof which are clearly within the scope of the invention will be apparent to those skilled in the art.

I claim: 1 l. A process for the preparation of an electrodeposit which contains iron and at least .one metal selected from the group consisting of nickel and cobalt which comprises passing current from an-anode to a cathode through an aqueous acidic electroplating solution-containing an iron compound and at least one member selected from the group consisting of cobalt compounds and nickel compounds providing cobalt or nickel ions for electrodepositing alloys of iron with cobalt and/or nickel and containing in combination:

1. at least one member selected from the group of cooperating additives consisting of: a. 0.005 gram per liter to 0.2 gram per liter of primary brightener b. 1.0 gram per liter to 30 grams per liter of secondary brightener c. 0.5 gram per liter to 10 grams per liter of secondary auxiliary brightener d. 0.05 gram per liter to 1 gram per liter of anti-pitting agent; 2. 0.5 gram per liter to 5 grams per liter of an organic hydroxy-sulfonate compound of the formula:

wherein M is a cation having a valence of 1-2; k is an integer l2 corresponding to the valence of M; and R is hydrogen or a monovalent aliphatic group of ll6 carbon atoms;

3. 10 grams per liter to 60 grams per liter of an hydroxy-carboxylate complexing compound or a polyol complexing compound selected from the group consisting of mannitol, sorbitol and dulcitol; and

4. 0.1 gram per liter to 5 grams per liter of an iodide of a bath compatible cation or a compound providing an iodide anion.

2. The process of claim 1 wherein said primary brightener is 1,4-di-(B-hydroxy ethoxy-Z-butyne).

3. The process of claim 1 wherein said primary brightener is 1,4-di-(B-hydroxy propoxy-Z-butyne).

4. The process of claim 1 wherein said organic hydroxy-sulfonate compound is sodium formaldehyde bisulfite.

14 5. The process .of claim 1 wherein said hydroxy-carboxylate is sodium tartrate dihydrate.

6. The process of claim 1 wherein said hydroxy-carboxylate compoundis malic acid.

7. The process of claim 1 wherein said hydroxy-carboxylate compound is sodium citrate dihydrate.

8. The process of claim 1 wherein said hydroxy-carboxylate compound is sodium glycolate.

9. The process of claim 1 wherein said hydroxy-carboxylate compound is sodium boroglucoheptonate.

10: An aqueous acidic electroplating solution containing at least-one ferrous compound and at least one member selected from the group consisting of nickel compounds and cobalt compounds, providing ions for electrodepositing cobalt-iron alloy, nickel-iron alloy, or nickel-'cobalt-iron alloy and containing in combination:

1 at'leastonemember selected from the group of cooperating additives consisting of: a. 0.005 gram per liter to 0.2 gram per liter of primary brightener b. 1.0 gram per liter to 30 grams per liter of secondary brightener c. 0.5 gram per liter to 10 grams per liter of secondary auxiliary brightener i d. 0.05 gram per liter to 1 gram per liter of'anti-pitting agent; 2. 0.5 gram per liter to 5 grams per liter of an organic hydroxy-sulfonate compound of the formula:

11. A process for the preparation of a cobalt-iron electrodeposit which comprises passing current from an anode to a cathode through an aqueous acidic plating solution containing 200 grams per liter to 500 grams per liter of cobalt sulfate, 45 grams per liter to grams per liter of cobalt chloride, 15 grams per liter to 60 grams per liter of boric acid, 0.5 gram per liter to 5 grams per liter of erythorbic acid, 0.5 gram per liter to 10 grams per liter of sodium formaldehyde bisulfite, 0.1 gram per liter to 5 grams per liter of potassium iodide, 1.0 gram per liter to 30 grams per liter of sodium saccharinate, 0.5 gram per liter to l0 grams per liter of sodium allyl sulfonate, 5 grams per liter to 60 grams per liter of ferrous sulfate, and 0.005 gram per liter to 0.2 gram per liter of diethoxylated butynediol.

12. The composition of claim 11 wherein said primary brightener is 1,4-di-(B-hydroxy ethoxy-2- butyne).

13. The composition of claim 11 wherein said primary brightener is 1,4-di-(B-hydroxy propoxy-2- butyne).

14. The composition of claim 11 wherein said organic hydroxy-sulfonate compound is sodium formaldehyde bisulfite.

15. The composition of claim 11 wherein said hydroxy-carboxylate is sodium tartrate dihydrate.

16. The composition of claim 11 wherein said hydroxy-carboxylate compound is malic acid.

17. The composition of claim 11 wherein said hydroXy-carboxylate compound is sodium citrate dihydrate.

18. The composition of claim 11 wherein said hydroxy-carboxylate compound is sodium glycolate.

19. The composition of claim 11 wherein said hydroxy-carboxylate compound is sodium boroglucoheptonate.

20. The composition as claimed in claim 11 wherein said nickel compounds are nickel sulfate and nickel chloride.

21. The composition as claimed in claim 11 wherein said nickel compounds are nickel sulfamate and nickel chloride.

22. The composition as claimed in claim 11 wherein said cobalt compounds are cobalt sulfate and cobalt chloride.

23. The composition as claimed in claim 11 wherein said cobalt compounds are cobalt sulfamate and cobalt chloride.

24. The composition as claimed in claim 11 wherein said ferrous compound is ferrous sulfate or ferrous chloride.

25. An aqueous acidic electroplating solution which contains 200 grams per liter to 500 grams per liter of cobalt sulfate, 45 grams per liter to grams per liter of cobalt chloride, 15 grams per liter to 60 grams per liter of boric acid, 10 grams per liter to 60 grams per liter of sorbitol, 0.5 gram per liter to 5 grams per liter of erythorbic acid, 0.5 gram per liter to 10 grams per liter of sodium formaldehyde bisulfite, 0.1 gram per liter to 5 grams per liter of potassium iodide, 1.0 grams per liter to 30 grams per liter of sodium saccharinate, 0.5 gram per liter to 10 grams per liter of sodium allyl sulfonate, 5 grams per liter to 60 grams per liter of ferrous sulfate, and 0.005 gram per liter to 0.2 gram per liter of diethoxylated butynediol.

Claims

1. A PROCESS FOR THE PREPARATION OF AN ELECTRODEPOSIT WHICH CONTAINS IRON AND AT LEAST ONE METAL SELECTED FROM THE GROUP CONSISTING OF NICKEL AND COBALT WHICH COMPRISES PASSING CURRENT FROM AN ANODE TO A CATHODE THROUGH AN QUEOUS ACIDOC ELECTROPLATING SOLUTION CONTAINING AN IRON COMPOUND AND AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OF COBALT OR COMPOUNDS AND A NICKEL COMPOUNDS PROVIDING COBALT OR NICKEL IONS FOR ELECTRODEPOSITING ALLOYS OF IRON WITH COBALT AND/OR NICKEL AND CONTANING IN COMBINATION:

2. 0.5 gram per liter to 5 grams per liter of an organic hydroxy-sulfonate compound of the formula:

2. The process of claim 1 wherein said primary brightener is 1,4-di-( Beta -hydroxy ethoxy-2-butyne).

3. The process of claim 1 wherein said primary brightener is 1, 4-di-( Beta -hydroxy propoxy-2-butyne).

5. The process of claim 1 wherein said hydroxy-carboxylate is sodium tartrate dihydrate.

6. The process of claim 1 wherein said hydroxy-carboxylate compound is malic acid.

10. An aqueous acidic electroplating solution containing at least one ferrous compound and at least one mEmber selected from the group consisting of nickel compounds and cobalt compounds, providing ions for electrodepositing cobalt-iron alloy, nickel-iron alloy, or nickel-cobalt-iron alloy and containing in combination:

11. A PROCESS FOR THE PREPARATION OF A COBALT-IRON ELECTRODEPOSIT WHICH COMPRISES PASSING CURRENT FROM AN ANODE TO A CATHODE THROUGH AN AQUEOUS ACIDIC PLATING SOLUTION CONTAINING 200 GRAMS PER LITER TO 500 GRAMS PER LITER OF COBALT SULFATE, 45 GRAMS PER LITER TO 80 GRAMS PER LITER OF COBALT CHLORIDE, 15 GRAMS PER LITER TO 60 GRAMS PER LITER OF BORIC ACID, 0.5 GRAM PER LITER TO 5 GRAMS PER LITER OF ERYTHORBIC ACID, 0.5 GRAM PER LITER TO 10 GRAMS PER LITER OF SODIUM FORMALDEHYDE BISULFITE, 0.1 GRAM PER LITER TO 5 GRAMS PER LITER OF POTASSIUM IODIDE, 1.0 GRAM PER LITER TO 30 GRAMS PER LITER OF SODIUM SACCHARINATE, 0.5 GRAM PER LITER TO 10 GRAMS PER LITER OF SODIUM ALLYL SULFONATE, 5 GRMS PER LITER TO 60 GRAMS PER LITER OF FERROUS SULFATE, AND 0.005 GRAM PER LITER TO 0.2 GRAM PER LITER OF DIETHOXYLATED BYTYNEDIOL.

12. The composition of claim 11 wherein said primary brightener is 1,4-di-( Beta -hydroxy ethoxy-2-butyne).

13. The composition of claim 11 wherein said primary brightener is 1,4-di-( Beta -hydroxy propoxy-2-butyne).

25. An aqueous acidic electroplating solution which contains 200 grams per liter to 500 grams per liter of cobalt sulfate, 45 grams per liter to 80 grams per liteR of cobalt chloride, 15 grams per liter to 60 grams per liter of boric acid, 10 grams per liter to 60 grams per liter of sorbitol, 0.5 gram per liter to 5 grams per liter of erythorbic acid, 0.5 gram per liter to 10 grams per liter of sodium formaldehyde bisulfite, 0.1 gram per liter to 5 grams per liter of potassium iodide, 1.0 grams per liter to 30 grams per liter of sodium saccharinate, 0.5 gram per liter to 10 grams per liter of sodium allyl sulfonate, 5 grams per liter to 60 grams per liter of ferrous sulfate, and 0.005 gram per liter to 0.2 gram per liter of diethoxylated butynediol.