DE2137805A1 - Process for the production of shiny, decorative composite chrome layers - Google Patents

Description

Priority: 2108.1970 - U.S.A.

The invention relates to new composite metal coverings «, which have an improved © corrosion resistance, and on methods and compositions for d ± © manufacture such composite metal coverings «»

It is known that different combinations of galvanic metal coverings can be used. and smoothing besitaea * are threefold aGhschichtnickalsystame in technology, whether the quantities of sulfur in a single blow is ₅ around the potential ratio of the ji © d®rsöhläge

209809/1458

to control in a certain way. Electroplated chromium deposits have been used on electroplated Mckel and Nickel alloy deposits in combination with copper or nickel underlay and a copper / E nickel alloy overlay. The known methods and the known composite coverings have relatively thick individual layers. When a film is made thinner, it may be necessary in another portion of the composite article, a thicker layer to use * It is also known _v that composite galvanic deposition in a specific physical or chemical property particularly may be good, such as respect gloss or resistance to electrochemical etching, but they are then deficient in other properties, such as corrosion resistance, ductility or uniformity due to the different deposition processes / were used for manufacturing the composite metal objects.

An object of the invention is to provide a new shiny, decorative To create composite chrome coating, which under unfavorable physical and chemical conditions improved Has corrosion resistance. Another object of the invention is to provide new shiny, decorative To create a composite chrome coating, using an extremely thin layer of cobalt as a source of precipitation will. Other goals will emerge from the description below.

It has now been found that unexpectedly corrosion-resistant shiny decorative composite chrome coverings thereby can be made so that a first © layer *

209809/1458

made of copper, a second thin layer of shiny cobalt, a third thin layer of nickel and a fourth layer shining decorative chrome deposited »whereby» to the invention Bath compositions used.

The inventive method for producing a corrosion-resistant, shiny decorative composite chrome coating is carried out by

1. deposits a first layer of copper on a base material;

2. on the copper layer a thin one A layer of shiny cobalt is deposited;

3 * a third thin layer on the cobalt top

nickel-containing layer with a thickness of

2.0 to 12.0 ^ separates; and 4. Galvanically stop at the third nod!

Layer a fourth layer of glossy

decorative chrome deposits.

Examples of base materials coated according to the invention can be made to have a corrosion-resistant, shiny finish to produce decorative composite chrome plating are: iron alloys, like B * steel, copper, nickel, ffessing, Broc £ 0, zinc or alloys made from these metals, as well as plastics, such as (ABS) aerylonitrile / butadies / styrene, polypropylene, Polyethylene, polystyrene and polyacrylic resins, etc. Particularly good results are obtained when the base material consists of steel or an injection-molded part, or if the base material is ABS »

BAD OFUGIN ^AU 209809 / U58

The first stage of the process according to the invention consists in depositing a copper layer on the base material, which is hereinafter referred to as the first layer or the base layer. The first copper layer can be deposited on a zinc injection-molded part or on another base metal by depositing copper, for example, from a cyanide-copper bath, an iyrophosphate-copper bath or an acidic copper bath. Such baths can typically have the compositions given in Table 1 , all values being given in g / l? unless otherwise stated *

Table I. component

(A)

Cu *

(B)

(0)

free KCN (or ITaCH)

* added as copper «
cyanide CuCN

Ou (BI ₄ ) -

HBF ₄ H3BO Cl

CuSO ₄ .

Sulfuric acid susatz

Minimum maximum preferred

45
15th

18th

200 500 225 1.5 5.0 5.5 5.0 25.0 13.0 0.01 0.20 0.05 180 (Saturation) 240 70 80 75 10 20th 15th

BATH ORIGINAL

209803/1458

The bath (B) can additionally contain a heterocyclic urea in amounts of 0.5-10 ^ 0 g / l (preferably 0.7-4 · ₉₀ g / l) in combination with a polyether carrier in amounts of 0.005-10 g / l (preferably 0.1 - 1.0 g / l) and a polysulfide of the formula HaOxS (CH ₂ ^ SS- ^ QH ₂ ^ T SO ₃ Na in quantities of 0 _$ 001 g / l to 1.0 g / l ( preferably 0.005 g / l ~ 0.2 g / l) if extremely leveled, shiny copper deposits are desired.

The additive for a bath of the composition (G) is preferably Bochelle-Saiz "Pheaolsulfonsäur © etc." The Roeh @ ll @ -3alss is preferably used in amounts of 10-20 g / l, usually about 15 g / l5. The deposition of the first copper layer using the bath (A) can be carried out by electroplating for 8-18 m 3 ^{, for example 10 min, at 60-70 0} G, for example 65 ⁰ G ₉

an Eathödenstroffidicht © voa 3-6 A / dm, for example M- , 5 A / tlss φ is used »Torsugsweisa the bath is stirred, for example by air or ^: through B © ¥ © ges, aar cathode» During this time Isasaa Κηρϊ ®τ with @ in © r Diek © voa tjpisehervjaisa 15 - 25 / & - mi &. precautionary © taagafähi? to be separated "

The galvanic deposition fies * @ 2? St © n Supfersslalöb.t aas @iaam sauren Kpfsrfeaa kaaa b @ i 40 * = 50 ° ö ₉ at ^ ielsWaist 4 · 5®05, while 3 _a 5 ~ 35 aiia odss »® elir ₉ b @ iapieisweis® 25 ®ia ₅ violent air spray executed "YjS2 ⁵ ä © a ₂ where eia © stromdioht © voa 1 ~ 5 A / da °°?" b © ispi © lsti © is © 3 A / da det

The © 2? © t © £ mpf © s? Seliielit kaas also a

Bad uiafe Susaas ^ asefcsuag ₅ uiö si # la

09809 / U5

Table II Component minimum maximum preferred

Cu ⁺⁺ 20 30 25

P ₀ O "~ 140 210 175

The electrodeposition of the first copper layer a pyrophosphate copper bath can be used at temperatures of 40-60 ° 0, for example 50 ° 0, for 5 * 5 to 35 min or more »for example 25 min, carried out with vigorous air agitation, whereby a cathode current diameter of 1-4 A / dm ^, for example 3 A / dm is used »

The base material, typically either (a) a zinc die casting or (b) a steel piece with the first copper deposit, is then further treated in accordance with the invention. A second thin layer of cobalt with a thickness of 0.25-5.0 ^ (preferably 1.3-2.8 / ^) is then preferably applied to the base material. The second thin layer of shiny cobalt can be made from a galvanic cobalt bath are deposited, as indicated in the following Table III "Sine more H ^ ßnahme is the decomposition of cobalt carbonyl under Abscheiduag a thin shiny cobalt layer" Ever comes _c jsd © s method into consideration., which is aur Prod @ llmag eiasr thin öobaltschicht suitable.

typical 0obal ^r öbäd © r ₉ di © g @ iaäS of the Irfinduni can be used, aind di @ following © » ₃ i / Ölöii © la aqueous solution the

in g / i

BAD ORICNAL

Tabel A. Sulpharaate bath III ife.ximum "prevent Components Go (as 00 (O ₅ SUHg) ₂ , Hinimum 400 300 GoOl ₂ .6H ₂ O and / or 65
5.0 45
3.2 H _x BO ₃ ,
Saccharin 200 4.5 2.3 Sodium allyl sulfonate 25th
I ₉ O 0.5 0 * 05 Bis-ß-hydroxyethyl
ether of 2-butyne-1,4-diol 1.5 0.5 0.125 Sodium-di-n-hexyl-suead 0.001 4 _? 5 3.8 pH (electrometric) 0.05 B. Fluoborate bath 2.5 maximum fairy adorned Components 500 300 Co (BF ₄ ) ,, Hinimum 50 45 H ₅ BO ₅ 200 50 45 HBF ₄ 30th 6th 3 pH (electrometric) 30th 2

G* Pyro-pnoBTphat bath Components

Hlnimiam

Potassium pyrophospaat
(laydated) 50 100 60 Oobalt Sulphate (hydrated) 60 150 90 citric acid 10 15th Coalt chloride 25th 50 30th

2Q9809 / 1453

Table III cont.

D. Chloride bath components

.6HgO

H ₅ BO ₃

3S. Salt bath Components

Cobalt sulfate (hydrated) Cobalt chloride (hydrated) boric acid

Minimum maximum preferred

200 30

500 50

30th

Minimum maximum preferred

200 350 300 30th 60 50 30th 40 35

! In the galvanic deposition of the second thin layer of glossy ductile cobalt using in Table III indicated baths cathode current densities of 1-10 l / dm, for example, 5 A / dm, and temperatures of 50-60 ⁰ C, for example 55 ° ^c »As well as the deposition times of StO - 1Q min, for example 5 min. -, usually 1 * 3 - 2.8 / 6, and especially about 2.5 / I- ■.

In the bath compositions used according to the invention compatible cooperating additives can be incorporated. Such cooperating additives are e.g .: aromatic sulfonates, sulfonamides or sulfonimides (such as sodium benzene sulfonate. Saccharin, bibenzenesulfonimld, etc.); aliiphatic or aromatic-aliphatically unsaturated sulfonates (such as sodium allyl sulfonate, sodium 3-chloro-2-butene-1-

BATH ORIGINAL

209809/1458

sulfonate, sodium beta-styrene sulfonate, etc.) »aeetyleniseh unsaturated compounds (such as 2-butyne-1,4-diol and its di-, tetra- and hexasubstituted ethylene oxide adducts; 2-methyl-2-butyn-2-ol and its ethylene oxide adducts; N-heterocycles, such as N-1,2 ~ chloropropenyl ~ pyridinium chloride, N ~ allyl chloraldinium bromide; 2,4,6-iDrimethyl-N-propargyl-pyridinium bromide; anionic anti-cigarette agents, such as sodium lauryl sulfate, sodium di ~ n * - hexyl sulfosuccinate, sodium 2-ethyl-h.exyl sulfate; active Sulfur-introducing compounds, such as aromatic sulfinates (such as sodium benzene monosulfinate), bis-omega-sulfopropyl sulfide (Sodium salt), etc.

According to the invention, a third nickel-containing layer is electrodeposited on the second ductile thin layer of shiny cobalt. The third thin nickel-containing layer can have a thickness of approximately 2 - Λ2 / 1 . Typisckerweise is the thickness of the third layer from 3.0 to 8.0 fo, preferably 4.0 to 7, QM and particularly about 5 / t.

According to the invention, a third nickel-containing layer can be deposited which consists of nickel or which consists of a nickel / cobalt alloy * The Electrodeposition of the nickel can be done from baths that contain nickel sulfate, a chloride, typically Nickel chloride, a buffer, typically boric acid, and a wetting agent contain * Other baths can be used as a source of nickel a combination of nickel fluorate with nickel sulfate and nickel chloride or a combination of nickel sulfamate and nickel chloride.! Typical Watts and high chloride baths are in the the following (Tables IV and V given.

209809 / U58

Components

Nickel Sulphate Nickel Chloride Boric Acid Temperature ( ⁰ G) Stir

PH

Table IV maximum preferred Watts bath 400 300 minimum 75 60 200 50 40 30th 65 50 50 38

mechanical and / or air or pumping the solution, etc.

2.5 4.5 3.5

Components

Nickel Chloride Nickel Sulphate Boric Acid Temperature ( ^{0 C) Lead}

pH

Table ν maximum preferred Chloride bath 300 225 minimum 150 85 150 50 40 40 65 55 30th 38

mechanical and / or air or pumping the solution, etc.

2.5 4.5 3.5

In the electroplating baths of Tables 17 and V, primary nickel polishers can also be used in quantities of 0.002-0.2 g / l, for example 0.05 g / l; secondary glossers in amounts of 1-30 g / l, for example 5 β / l? and secondary auxiliaries may be present in amounts of 0.5-3 g / L, for example 1 g / L. Typical primary Glänz sr are, for example, acetylenic compounds, such as 2-butyn-1 _i 4-diol, or pyridinium compounds, such as, for example, quaternized pyridine derivatives.

09809 / U58

Typical secondary glossers are, for example, compounds containing sulfur and oxygen, such as ZeE. Saccharin, sodium benzenesulfonate etc. A typical secondary auxiliary shimmer is, for example Sodium allyl sulfonate.

The deposition of the third niekelhaltigen Söhioht can at 40 - 60 ⁰ C, for example 50 ⁰ O, and at a pH of 2.5 to 4.5, for example 5 »5» min while 8-14, for example 10 minutes, are executed, with a nickel-containing coating with a thickness of 2 - Λ2 / 1, for example 5Α ^ ^{Γίι & 1} * ^θη . Nickel alloys, such as aB * Sickel / 0obalt <5 & gierusgen, can also be used as a third layer. applying a shiny kick layer and then a shiny layer, the total nickel-containing layer being about 3 - 6/4, "fertilizing hickal becomes the third nickel-containing layer t

! The Bick & lsehicht kesii. as already erwilat ₉ glitas @ n & seia, but other dekerati ^ ® Niek @ lb © llg @ can also be used, such as ζ · Β. such ©, - dl © a © silky or iron-brushed surface texture, whereby this surface texture is achieved by mechanical © des? other vibrations are caused »

the third thin splints ice, ® nickelh & DEFINITELY Bohicht is Dana the thin © Nickelsehieht preferably in © iners two-stage process is prepared, which is executed © dadisrch which is to ® ± n base material * having a conductive metal surface of cobalt sait a thickness of about 0.25 - 5. OyC *, «unlehst a

209809 / U58. ^{BATHROOM 0RK3INAL}

Layer made of (particles with a particle size of approximately 0.05 "- 5 _e O / fr and a density τοπ 100 to 5-000,000 part

2
chen / cm applied and then AASS in dieeer laying of particles of a conductive nickel-containing layer in a thickness of 0.25 - 5 0 JU / deposits, is thinner than the maximum thickness of said partial double layer, with a nickel-containing matrix ersielt TVIRD ₅ in which the particles are held in a fixed position in the conductive nickel-containing layer, at least a portion of these particles passing through the surface of the conductive nickel-containing layer. Typical galvanic baths and processes for the production of matrix layers containing zero are specified in US patent application 767 972, to which reference is made here *

Typical baths which can be used according to the invention are the baths of Tables IV and V as well as baths, which are given in Tables Vi-X, where all values are expressed in g / l, unless otherwise stated.

A typical sulfeinate bath used in accordance with the invention contains the following components in an aqueous solution (g / l, unless otherwise stated is).

Table VI

component minimum maximum preferred Nickel sulfamate 330 400 375 Milk chloride (hydrated) 15th 60 45 Boric acid 33 55 45 pH 3 5 4.0

BAD 2098Ü9 / US8

A typical chloride-free sulfate bath made according to the invention contains the following components in aqueous solutionj

Tabel YlI maximum preferred component minimum 500
55
5 400
45
4.0 Nickel sulfate
Boric acid
pH (hydrated) 300
35
3

A typical chloride-free sulfamate bath which can be used in accordance with the invention contains the following components in aqueous solution;

Table VIII maximum preferred component minimum 400
55
5 350
45
4.0 Niekel sulfamate
Boric acid
pH 300
35
3

A typical pyrophosphate bath made according to the invention contains the following components in aqueous solution:

component

Sodium Pyrophosphate (hydrated) Nickel Sulphate (hydrated) Sodium bisulfite sodium citrate (hydrated)

BATH 209809 / U58

Table IX maximum preferred minimum 80 65 50 160 120 ert) 80 2.5 2 "U5 70 60 iert) 50

Table IX cont.

component

citric acid
Sodium chloride
Ammonia (28%)
pH

minimum maximum bevorsufffc 10 20th 15th ^J 20 40 50 50 60 50 7.5 9 8.5

A typical IPluoborate bath, which according to the invention ver * contains the following components in aqueous solution:

Table X

Component Minimu m

Nickel fluoborate (hydrated) 250

Nickel chloride (hydrated) 15

Boric acid 15

pH 2

maximum preferred 400 500 60 · 50 50 20th 4th 5.0

A typical nickel / cobalt alloy bath contains the following Components in g / l in aqueous solution:

component

.6H ₂ O

H ₃ BO ₃ ,

Minimum maximum preferred

400 500

15 225 80

15 75 60

50 50 45

209809 / U58

It goes without saying that the baths can contain the components in amounts outside the stated maximums and minimums, but the most satisfactory and economical operation is normally obtained when the _five components are included in the baths in the amounts indicated.

If the third thin layer containing nickel is a nickel / cobalt alloy layer (which typically contains about 25-50 wt.% cobalt), then the third can be nickel-containing Layer are deposited from a conventional bath, which contains both nickel and cobalt ions, with the Electricity and the auxiliary system so chooses that from the same Bath first a cobalt layer and then a layer of a nickel / cobalt alloy is deposited.

If the thin third layer consists of semi-bright nickel, an aliphatic aldehyde is usually used in combination with a wetting agent such as sodium di-nhexyl-sulfosuecinate, the bath containing 200-400 g / l NiSO ₄ .7H ₂ C.

The baths can therefore contain glossers that are compatible with the bath or other additives that are compatible with the bath, such as Sodium saccharate, wetting agents, etc. High foaming wetting agents, such as sodium laury sulfate can do particularly well be used «when a mechanical guide is used. Low foaming agents such as sodium dialkyl sulfosuccinate are particularly beneficial when air circulation is used.

In a preferred method of operation according to the invention the base material a first copper layer, a second thin cobalt layer (preferably with a thickness of

209809 / U58

0.25 - 5 »0 / Oi on which there is then a layer of particles with a particle size of about 0.05-6.0 / i which a third thin nickel-containing layer is deposited so that a nickel matrix of 2-12 ^ and a sulfur content of less than 0 * 1% by weight is produced, whereupon a fourth layer of shiny decorative chrome is deposited will*

The use of a matrix allows the use of lower effective thicknesses compared to nickel or nickel Uickel / cobalt alloys. A microscopic examination the matrix shows that the particles are held in a matrix of the third thin nickel-containing layer It can also be observed (for example through dark field lighting in a microscope or by the Dubpernell test) that the particles pass through the nickel-containing layer can pass through and that they can be observed over the upper surface *

The composite product produced in this way thus typically contains the following: a first copper layer, a second cobalt layer (preferably 0.25 to 5.0 / 06 thick), a third thin nickel-containing layer with a thickness of 2-12 / £ which preferably has an optical content of less than about 0.1% by weight, based on the weight of the nickel-containing layer, and which has been produced by adding 100 5,000,000 onto the second thin layer of shiny cobalt Particles / cm ² with a size of 0.05 each -

applies and these particles fixed in a thin nickel-containing matrix, at least a portion of these Seeing particles through the nickel-containing matrix and cutting through its surface.

209809/1458

The nickel matrix layer is produced by placing the object coated with cobalt (which therefore has a thin layer of shiny cobalt) in a dispersion bath 5 which has suspended particles with a size of approximately 0.05-5 % O / C. The article coated with glossy cobalt can remain immersed in this dispersion for a certain period of time (for example about 30 seconds), which time is sufficient for a layer of particles to form thereon. Then it is removed and transferred to a matrix bath, in which a conductive layer of .shining nickel is applied. The nickel plating bath (which is treated with activated carbon from time to time and filtered to keep the solution free of impurities and insolubles) can hold 300 g of nickel sulfate heptahydrate _? 60 g of nickel chloride hexahydrate _{s contains} 45 g of boric acid and water up to one liter and has a pH of 4.0 (electrometric). A wide variety of dispersed materials can be used to make the nickel matrix, such as particles made from the following materials: talc, kaolin; Wax ₅ graphite; Sulfides such as hydrogen disulfide and tungsten disulfide; Pigments such as barite ₉ chromium / cobalt green and cobalt / aluminum blue and oxides such as silicon dioxide and aluminum oxide; Plastic particles such as particles of polymers or copolymers of styrene, butadiene, acrylonitrile, vinyl acetate, vinyl chloride, etc .; Diatomaceous earth; powdered aluminum; Activated carbon; Silicates =, such as sodium silicate; Carbonates «such as, for example, potassium carbonate; Carbides $ sulfur; and mixtures of these materials.

There may also be other additives, such as polar organic compounds, for example amides, amines, long-chain alcohols, acetylenic compounds, etc. to improve properties, adhesion, or inhibition

209809/1458

Improve dispersion *

The application of the particles can be carried out by coating the base material with the particles Particles can be blown over the metal surface of the base material «Bas base material can also be blown into a bed of the particles, preferably using a fluidized bed, i.e. a bed in in which the particles are suspended in an upwardly flowing gas stream. You can attach the particles through electrostatic or electrophoretic techniques are done. Optionally, the base metal can be wet to the To support adhesion of the particles "

The particles can be used in the form of a bath, i. in the form of a suspension, emulsion, dispersion or a latex of the solid or semi-solid particles in a medium, preferably a liquid. In a preferred embodiment, solid particles are suspended in a liquid, the concentration being only 0.001%, typically 0.1-2% and preferably about 0.5%. Extraordinary Results can be obtained using baths containing 0.1 to 2% particles

Commercially available materials can typically be used as the particles in the bath. An example of this is talc, which is available with a particle size in the range up to about 7/1 . 0.1-2% talc can be introduced into water and dispersed, for example by grinding in a ball mill or in a Waring mixer, or by stirring. Similar techniques can be used to disperse wax, pigments, kaolin, etc.

209309/1458

The medium in which the particles are suspended can consist of water; but it is preferably a bath with a composition similar to the bath used immediately before, from which the building material for the further Treatment is removed "such as a water rinsing bath or a galvanic nickel bath"

Typical particles can be applied from a bath in the form of a dispersion that is 0 * 005 - 5 (preferably 0.5) Weight parts talc? 95 - 100 (preferably about 100) Parts by weight of water; 0.00005 - 0 ^ 10 (preferably about 0.01) Parts by weight of dirnethyloleamide; and 0.00005-0.10 (preferably contains approximately 0.01} parts by weight of sodium lignosulfonate.

The application of the particles on the thin Oobaltsehicht is preferably carried out by immersing the metal surface in an aqueous bath containing the particles "the dipping can occur at room temperature of about 10-40 ⁰ C are performed. The surface is left in the bath long enough to cover the surface, typically 5 to 60 seconds, preferably about 30 seconds. Moderate agitation at this stage is beneficial.

The surface can then be removed from the bath, whereupon it has a layer of particles which adhere evenly to the surface. Typically 100 is 5,000,000 Particles / cm and usually 5,000-2,000,000 particles / cm present on the surface. The on this Surface obtained in this way can optionally be left to dry or rinsed with water. She can too instantly processed wefcer (whereby they still carries a thin adhesive film of liquid). The subsequent nickel layer is deposited from a nickel bath, which is largely free of these particles

209809 / US8

to produce a conductive Uickelschicht that adheres to the ! Particles are penetrated, creating a nickel matrix.

The following examples illustrate typical particle hairdryers Materials that can be used in the indicated concentrations (expressed as% by weight).

209809 / U58

Grief
the dispersion

3 4th O 5 co OO
O 6th (O _7th tn 8th CD 9

11

Type of dispersed weight% alloyed material

Polyvinyl chloride 0.5 latex

Polyvinyl acetate 0.027 latex

Polyvinyl acetate-0.55 latex

Polyvinyl acetate

Latex 0.55

Styrene / butadiene-0.024

latex

MoS ₂ powder 1.0

WS ₂ powder 1.0

WSg powder 1.0

Talc 0.8

Talc 0.8

Talc 0.8

Graphite 1.0

Designation of the dispersed Materials and supplier

Dow 700

Dow Chemical Co.

Plyannil 40-370;
Reichhold Chemical Inc.

Gelva TS-30;

Shawingan Plastics Corp.

Gelva T8-30;

Shawingan Plastics Corp.

Pirestone PL-30;
Firestone Plastics Co.

nominal particle size

0.16
0.5 -

0.5
0.5

0.2

Consolidated Astronautics Inc.

0.4

0.4

Submicron WS2;
Bemol, Inc.
SubmicroL ·. WS2;
Bemol, Inc.

Mistron 2SC;

Sierra Talc & Chemical Co.

Mistron ZSC;

Sierra Talc & Chemical Co.

Mistron ZSC;

Sierra Talc & Chemical Co.

Aquadag;

Acheson Colloids Company

0.4-6 maximum

0.4-6 maximum 0.4-6 maximum

4.2 maximum

CO »J CO CD

Lobster of the dispersion

13th

14th

15th

16

209809 / 17th
18th * · »
«Π
approx 19th 20th 21st 22nd 25th

24

Type of diaper wt% yawed material

Graphite 0.1

Graphite .. 0.4

Graphite 1.6 chromium / cobalt pigment 1.0

Cobalt / aluminum 1.0 pigment

WBp powder + Cr / Co- 1.0 pigment

Talc 0.15

Talc 0.15

Talc

Talc 0.4

Potassium carbonate 0.2

colloidal sulfur 0.05

pergated material
and supplier Mills TiOBi-J pn 1 et ¹ PnA "|, f»> ^ «^ | -
large (y &) dumber 5530;
Asbury Graphite mils 2-5
Inc. JSuntoer 5530;
Asbury Graphite mils 2-5
Inc. Number 5530;
Asbury Graphite 2-5
Inc. V-7687;
Ferro Corp. 0.5 maximum V-3285; 0.5 maximum

; Ferror Corp.

Submicron WS2 and V-7687; 0.4 (WS ₂ ) and Bemol, Inc. and Ferro Corp. 0.5 maximum (Cr / Go)

Nietron Monomix; Sierra! CaIc * Chemicals Inc. Mistron Monomix; Sierra! CaIc & Chemicals Inc.

0.15 matron Monomix;

Sierra Talc & Chemicals Inc.

1.0-6 maximum

1.0-6 maximum

1.0-6 maximum 1.0-6 maximum

Mistron Monomix; Sierra Sharks & Chemicals Inc. Camel white; 10 maximum Harry T. Campbell Sons Corp.

made by pouring a hot saturated solution of sulfur in alcohol - in water

Either one can prepare the above immersion dispersion Water or the nickel or cobalt electrolyte used In any case, the object covered with cobalt, which has the adhering particles, a thin layer of nickel from one or more of the hie? described nickel-containing baths. The baths containing nicotine are kept largely free of the particles that are in the üauchdispersion are present.

The objects with the three layers a thin layer of a nickel matrix having a thickness of 2 - have Λ2 // can then be further provided with a decorative chrome coating ·, the chromium plating can be at temperatures of 30 - 60 ^0C, for example, 43 ° C and b @ i current

'.ρ ο

densities of 5-50 A / dm, for example 10 k / ßm , for 0.5-15 min, for example 5 min, carried out * using baths, ie 100-500 g / l, for example 250 g / l chromic acid and 1-5 g / l «for example 2.5 g / l sulphate ions, which are typically derived from sodium sulphate. In the yerchroarang baths, other components may also be present, such as other 7-chromium catalysts, for example fluoride silicofluoride, or other complex fluorides, self-regulating strontium-containing compositions, substances that suppress the formation of vapors, etc.

The chrome layer produced by the method according to the invention can be at least about 0.02 / £ (decorative Thicknesses are less than about 1/0 made will. They are particularly characterized by @in shiny decorative appearance, high corrosion resistance and © iae micro-cracked and microporous structure. the

BATH ORIGINAL 209809 / 1AS8

Chromium light, which is preferably contained on the particles Nickel matrix layer is applied, the particles partially over the surface of the nickel-containing matrix layer protruding can exhibit microcracking and microporosity over substantially the entire surface.

The micro-cracked surface of the chrome layer, which is produced in the process according to the invention using the matrix described above, has at least 100 cracks per linear centimeter at a distance of 40 mm from the end of high current density in a standard Eull cell with 10 A. Plate coated for 5 min at 43 ° C, whereas the same chromium layer in a typical known Uickel base has only 2-4 microcracks per linear centimeter and the mean current density au. The high microcracking extends largely over the surface of the chrome layer and merges seamlessly into the microporous areas which are characteristic of the areas of low current density in the plating of the matrix surface according to the invention.

When examining this product under a microscope, then it is found that there is a microporous surface in the low current density region of the standard Hull cell Typically, the product of the process will contain a multiplicity of pores, typically about a hundred to two or three million (with a chrome thickness of less than about 0.5> C6> the pores being more or less uniformly distributed over the surface of the metal. A chrome deposited on dl® third thin nickel bar thus contains microporous areas and micro-cracked areas

209809 / USS

Distributed over the entire surface » Be it is believed that the presence of microporous areas (i.e. eatwe er the microporous areas or microcracked areas) on the entire surface of the chromium layer in conjunction with the underlying copper, cobalt and nickel layers produce the new beneficial results the invention allows.

When a chromium layer is applied to the copper / cobalt / knitted matrix layer system as described here5, unexpected advantages are achieved. If all of the other factors are constant, then the iciness of the chrome layer depends on its thickness. Such factors as the concentration of chromic acid, the concentration of the catalyst materials, the deposition temperature, etc. all have an influence. It is a characteristic of the known chromium plating processes that cracking does not occur during the first stage of the deposition up to about 0.5 / t. If the thickness increases, for example in the range of O _? 5 - 1, O ^, then undesirably strong cracks occur. In the likewise unfavorable third level of approximately 1.0 1.5 / έ, for example, a tinsel-like crack formation occurs * that is, M-cracks are interspersed in thick cracks. Only in the fourth stage alone does microcracking develop. The undesirable intermediate stages, ie stages two and three, have an unfavorable appearance. This is especially true after the cracks become more prominent due to the corrosion. The micro-pores and micro-cracks cannot be perceived by the naked eye because of their fine structure. The presence of these M cracks over the entire layer gives an exceptional resistance to corrosion.

BATHROOM OBlGSNAL

209809 / H58

It was unexpectedly found that the invention Process a microporosity is already generated in stage one and that facilitates the formation of microcracks so that in stages two and three the strong hoes or the tinsel-like bites do not appear step «The finished chrome plating has a low current density range microporosity and, in the higher current density range, micro-cracks, with no large individual cracks whatsoever and tinsel-like bite formation are present

The preferred thickness of the decorative shiny chrome plating can be 0.02 - 5 * 0 ^ »for example 0.5 / #». Of the Degree of microcracking (achieved at thicknesses greater than approximately 0.5 / ^) above a typical copper / cobalt / Nickel matrix layer can have at least 100 microcracks each linear centimeter.

In the following examples, unless otherwise specified, base metal plates were provided with a shiny copper layer in a standard bright copper bath. The shiny copper plates were then rinsed, whereupon a layer of .25 to £ 6 shining on them Cobalt (as indicated in Tables XI and XII) was deposited Plates immersed in a dispersion bath containing the suspended particles listed in Table XII contained. The metal plate that layers the thin cobalt was held in this bath to about 30 eek then to make a layer of particles. The plate was then removed and transferred to a matrix bath, in a conductive third nickel-containing layer has been deposited · The bath for the deposition of the nickel-containing layer

BATH ORIGINAL

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(from time to time it was treated with activated charcoal and filtered, to solve the problem of impurities and insolubles Contain substances) contains 300 @ nickel sulfate heptahydrate, 60 g of nickel chloride hexahydrate, 4-5 g of boric acid and water up to to 1 1. The pH was 4-.0. Such examples are given in Table XI in which the nickel layer did not contain any particles. Table XII contains the examples where an Ifickel matrix is present.

After deposition of the Niekeischieht the plate was rinsed with water and then _t plated in a bath ₅ containing 250 g / l chromic acid and 2.5 g / l sulfate (added as Hatriumsulfat) contained and which had a temperature of 45 ⁰ C.

In Tables XI, XII, XIII and XIV the GASS-Ein ~ gradations are given in Fora van pairs of numbers, with the first ; Number the degree of base metal corrosion and the second number indicates the appearance * DIs ratings range from 0-1O. The higher numbers indicate a better ranking Fourths out of 7-6 are acceptable.

Each example was done in duplicate with a steel plate. All plates finally received 0.25 / t Chrome done before testing for OASS classification became,

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I. copper Table XI layer OASS classification 44 hours Thickness (jt &) the .Nickel 22 hours at 25th 2. shine - 3 10/10 game
No. 25th of the cobalt VJl 10/10 10/10 1 25th 1 5 10/10 0/0 2 25th 1 6th 0/0 0/0 3 25th 0 " 6th 0/0 10/6 4th 25th 0 0 10/8 10/6 5 O 6th 0 .10 / 8 0/0 6th O 6th 5 3/2 0/0 7th 1 ' 5 8/7 8th 1

In Examples 3 and 4, "in which a layer of Hickel anst®li @ τοη 1y ££ cobalt and 5 / CHickel was used (in contrast to Examples 1 and 2, which explain the invention), the ClSS ratings were complete unsatisfactory (0/0), both after 22 hours and after 44 hours. The first layer of copper was omitted in Examples 7 and 8. It can be seen that the OASS classification was significantly worse than in the case of the 22 st Examples 1 md 2 _e ÖABS the classifications of Examples st In MA 7 and 8 completely imsufriedenstellend.

In the following "examples" a niokeliferous matrix was used used as a nickel-containing layer * The particles passed from talc (0.1% Salcum - Astron Honomir in water /. ? Before the determination of the GASS Sinstufuagen was a shift of 0.127 / X applied from Clirom.

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CASS ^ classification

With- 1. Copper 2. Glänsesi- 3 »Nickel- 22 st 44 st

game of the Cobalt Matrix

9
(Ver
same) 18th 0 , 625 , 7 * 6
(Glans-
nickel) 10/9 10/6 10 18th 0 * 25 1.8 10/10 10/10 11 18th 1 »5. 1 * 8 10/10 10/10 12th 18th 2 fO 1.8 10/10 10/10 13th 18th 5 1.8 10/10 10/10

As can be seen from Table XII, a low nickel strength can be used when a oil matrix is used, and the overall thickness of the cobalt and oil layer can also be reduced while still receiving exceptional CASS ratings.

In comparative example 9, a 7 »6 ^ tstarks (Jlanssniekel layer on the lie of the carbon layer and the nickel matrix layer verv; eadeb. The GlSö ratings were both at 22 st and 44 st lower.

In the following examples, comparisons were made in order to show the effect that arises when , instead of the first copper layer, as used in accordance with the invention, a first layer of nickel (made of two different layers of nickel) is used V.:elbäd@rn) siasetat.

The watery jrlanükuprerbac «. was the same as in Example 1 and eats 240 g / l CuSO ₄ .5H ₃ O, 60 g / l H

BATH

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0.06 g / l chloride ion, 1 ^ 0 g / l polyether and about 0.020 g / l sulfonated disulfide.

The first aqueous nickel bath which was used for the experiments given in Table XIII (designated bright nickel bath 1) contained JOO g / l NiSO ,,. ? H _o 0.60 g / l NiCl ₀ .6H _o 0.35 g / l Η, ΒΟ ,, 0.05 g / l primary '' gloss (mainly butynediol), 5 * 0 g / l secondary gloss (saccharin ) and 0.125 g / l wetting agent (sodium di-n-hexyl sulfosuccinate)

The second aqueous nickel bath which was used for the experiments given in Table XIII below (referred to as bright nickel bath 2) contained 300 g / l NiSO ^.? H ₂ 0.60 g / l NiOl ₂ .6H ₂ O, 35 g / l H ₅ BO ₅ , 0.02 g / l primary gloss (mainly acetylenic diol) and 0.125 g / l wetting agent (sodium di-n-hexyl sulfosuccinate).

The aqueous Glanzco'baltbad, which was used for the preparation of the gloss layer for the cobalt set forth in Table XIII testing _t containing 300 g / l CoSO ^ · 7H ₂ O, 60 g / l CoCl ₂ .6H ₂ O, 45 g / l H ₅ BO ₅ , 5.0 g / l saccharin, primary gloss (mainly butynediol) and wetting agent (sodium di-n-hexyl sulfosuccinate)

Identical steel plates were electroplated with the above baths. A 0.25 / C thickness was then added Chromium layer applied by electroplating, the chromium bath of Example 1 and the same deposition conditions were used. The results are in Table XIII summarized.

BAD ORlGiRAL

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! Table Uli
Thickness Cfc) of the deposited layer CASS grading

With- 1. first layer 2. gloss- 3 » gloss- 22 st

game cobalt nickel 1

44 3t

13 18 (bright copper) 2.5

14 18 (bright copper) 2.5

15 18 (bright nickel 1) 2.5

16 18 (bright nickel 2) 2 ₉ 5

1.8 1 * 8

10/10

10/10 10/10 10/9 10/7

From Table XIII, the first nickel layer can be seen with the same copper layer OASS-Einstufungesi _s @rgibt ringsr are.

di®? mentions a how

et ge

In the following examples (there are five in Table XI), the same steel plate as in Tersuchen of Tables XI - Uli v @ s? ^ ®M © to Di © sut © Kx _ was made of a layer aqueous glass button © röi, d ₉ tji © @ S3 for Table XIII is described «, under ¥ a.etasg mm ifientisehen deposition conditions the deposited Di © Diek® d © § copper was the same®. The aweit © Cob & ltseh sees mräe deposited in Ssalieher manner on the first copper layer ame @ ia @ a aqueous Glanscobaltbad, as © s ia table HII aag @ g © b © a. is, with identical deposition diagiisgeii applied% ns? the _v to a second glossy cobalt cliioht with © iner Siek © ir © a 2, produced as it is given in Table HT "Mae third nickel-containing layer with the thickness given in Table 217 under Yesw®nü.wo.s © ia © s Hiek®l / C © "& alt-Bads produced, which 240 g / l HiSO ₄₅ 60 g / l CoSO ₁ ^. 60 g / l MCl ₀ ο6H ₀ O and 45 g / l H ^ BO ^ contained.

et el ΐ? ·?

legisrte Anoaen of 80 wt _e -fö Micke 1 uad 20

BATH ORIGINAL

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The 0.25 / έ thick chrome layer was made in the same way and applied from the same bath as described in Example 1 is.

The comparison (Example 18) was identical in all respects to Example 17, with only a layer of semi-bright nickel with a thickness of 3/4 instead of the
2,3JU thick luster if the layer (layer 2) of Example 17 was used * The semi-glossy nickel layer was produced using a bath as described in US Pat. No. 3,486,989 and which is 300 g / l
NiSO ₄₄ 7H ₂ O, 45 g / l NiCl ₂ .6H ₂ O, 45 g / l H ₅ BO ₃ and 0.15 g / l
Fiperonal contained. An electrometrically measured pH of 3.8-4.0 was used. The results are in the table
XIV stated.

209809/1 458

example
Grief

table XIV

Thickness (/ 4) of the deposited layer 1. first layer 2. second layer

CASS classification

3 «shiny alloy of nickel 22 st 44 st
and cobalt '

18 (bright copper) 2.5 (bright cobalt) 1.8

10/10 10/9

18 18 (bright copper) 3.0 (semi-bright 1.8 (comparison) nickel)

10/9

10/6

--J OO O

As can be seen from Table SIV, the CASS ratings were for example 17 (according to the invention better than the classifications, obtained with the comparison, and ssw was at both 22 st and 44 st.

It is believed that the improved properties (especially the improved corrosion resistance) obtained according to the invention is due to the maintenance has a correct balance between the electrochemical activities in the various individual layers. It will believed that due to the fact that cobalt corrodes more rapidly than nickel or copper, there is considerable corrosion the cobalt layer arises when the corrosion paths reach this oobalt layer. Obviously the activity of the cobalt layer is not quite as sensitive to the Sulfur content, as is the case with a nickel layer, which is why the cobalt layer is a preferred corrosion tends »The relative activities of the metal layers of the composite coating can be obtained by that one compares the! potentials of these netalles with the standard calomel electrode in a 3% strength (by weight) aqueous sodium chloride solution saturated with air. It was found that the incorporation of cobalt into a shiny, sulphurous nickel coating was up to about 50 wt% has only a weak effect on this potential. However, if the oobalt content rises above 50 wt .- #, then the potential changes more rapidly in the more active direction. On the basis of these considerations it can be assumed It is suggested that cobalt protects the nickel and chromium in a similar way that zinc protects steel. This hypothesis is supported by photomicrographs of the cross-section of corroded precipitates, which show that corrosion pores, which are in the cobalt layer extend, also extend laterally, so that the cobalt layer preferentially corrodes, whereas the copper layer

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remains largely intact. So it is particularly surprising that extremely thin layers of cobalt can be used to to achieve effective corrosion improvement »

It is believed that the cobalt thin layers are therefore are effective because of the resistance to the path of electrical current through the relatively thin physical Ab-DBsstangen is increased, therefore the corrosion current between the cobalt and the chromium is decreased, although one Current is sufficiently large to prevent corrosion of the nickel.

209809 / U58

Claims (4)

Claims (λ7) Process for the production of a gl & BSt & the decorative composite chrome coating, thereby gekennselehnet that one (1) deposits a first layer of copper on a base metal; (2) deposits a second thin layer of cobalt on the copper; (5) on the cobalt layer a third thin nickel-containing layer with a thickness of 2 - 12 / έ separates; and (4) Electroplating a fourth layer of shiny decorative chrome on the third nickel layer « 2. The method according to claim 1, characterized © indicates that the second thin cobalt layer with a thickness of 0.25 - 5 * 0 ^ / 6 is deposited. 3. The method according to claim 1, characterized in that the third nickel-containing layer has a sulfur content of less as 0 * 1 wt .-%. 4. The method according to claim 3, characterized in that the third thin nickel-containing layer is thereby produced is to attach a layer of particles 0.05 in size to the second thin cobalt layer and which are present in a density of about 100 to 5,000,000 particles / cm, and that one is in this position a conductive thin nickel-containing layer with an effective thickness of 0.25 - 5.0 ^ deposited from particles, which is less than the maximum thickness of the particle layer, 209809 / U58 Of - whereby a matrix is formed in which the particles the cobalt surface are retained in the conductive thin nickel-containing layer, with at least some of the particles look through the surface of said conductive thin nickel-containing layer. 5 «Method according to claim 4, characterized in ₅ that the density of the particles on the thin cobalt layer 5000 to 2,000,000 particles / cm ^2, 6 »A process for producing a shiny _t decorative composite chromium coating, characterized in that (1) a © first layer on a base metal made of copper with a thickness of 5 * 0 - 50 / £ separates; (2) a second thin layer on top of the copper layer A layer of cobalt with a thickness of 0.25-5 is deposited 5 (5) A layer of particles having a particle size is deposited on the thin cobalt layer from about 0.05 - 6, O ^ and in a density of about 100 to 5,000,000 / cm exist; in this layer of particles a conductive thin metal layer with an effective Deposits a thickness of 0.25-5 »0 / £, the thinner than the maximum thickness of the layer of particles is to form a third thin layer of a to produce a nickel-containing matrix with a thickness of .0.25 - 5.0 ^; and (5) on the third thin layer of one nickel-containing matrix deposits a fourth layer of shiny decorative chrome. BATH 209809 / U58 7. The method according to claim 6, characterized in that the fourth layer of shiny decorative chrome has a thickness of at least approximately Q _% Q>2βA> . 209809 / U58