DE1621117A1 - Process for the electrolytic deposition of nickel coating - Google Patents

Description

description
to the patent application of

MSsS Chemicals Inc., Hew York, HOY ₀ * VoSt ₀ A ₀

concerning
Process for the electrolytic deposition of handle coatings

Priority χ 26.10 »1966

The invention relates to a new electroplating process «, In particular, it is looking at a new procedure for the electrolytic deposition of a hickel coating, which is characterized by the fact that it has a good protective effect results and can be plated with chrome, being a product is obtained that is extremely resistant to corrosion «,

¥ i © it is generally known _s may maa a plattiertas with chrome product characterized herstelX © n, one ämß a. Gxus & imetall

SAD

2-

100816/1701

«3 2 β» ■

A first plating made of a shiny nickel-plated steel that is characterized by its specificity and leveling, a second plating of bright nickel and a final ohrom plating however, it has been found to be unsatisfactory under extreme conditions. For example, if such a system is subjected to three cylinders of the standard CASS test (ASTM B380-61T) it is found that the surface shows signs of corrosion ₃ which is a loss the surface gloss and the surface gloss and a surface finish of the optical appearance. "These phenomena thus indicate unsatisfactory behavior during the course of the three cycles of the test that after a long period of time, the three Cycles of this Teat, to which the atmosphere is resistant «

The present invention is based on the object of creating a new nickel plating which is characterized by "that an ear plating with improved corrosion resistance can be deposited on it". A further object of the invention is to create a new chromium plating.

109816/1701 bad original

which is characterized by a high level of corrosion resistance, in particular long-lasting corrosion resistance based on

pleaded.

The present invention thus relates to a new process for the production of nickel surfaces, which are characterized in that they can accept a chrome plating with a high resistance to corrosion Bright nickel plating is immersed in an aqueous electroplating bath, since it contains about 120-187 g / l Ni ⁴⁺ , 110-225 g / l NiGl ₂ , 6H ₂ O and 500-900 g / l Ni (BF ₄ ) ₂ , and at least 0, SyM. an outer microris nickel plating from this bath is deposited _e

The base metal that can be plated according to the present invention can Iron including iron alloys, such as "steel, copper, Nickel, brass, bronze, zinc or an alloy of these metals be «The extraordinary results of the invention The process becomes particularly clear when the base metal is steel. “It is a special feature of the new process according to the invention that there is di <3 production of plated. Products with extraordinary and unexpected

109816/1701

-4-

BATH

Properties allowed if the material on which the plating is deposited is a zinc base casting,

Boi a particular Äusftihrungsform of erfindungegemäßen traversed, the first stage consist in depositing a precipitate of copper on the base metal "is referred to as" Kupferbasisplattierung _"B In the case of castings on Zinkbäsis these can be substantially" Xm case it can be omitted from other base metals, such as ζ.B _{0 steel} have the composition given in Table I below, in which all values are expressed in g / l, unless otherwise stated *

Table I. Maxinum preferred component minimum O CM
VO CM 52
18th Gu *
free KGK 45
15th

(or NaCN)

* added as copper cyanide CuCH ₀

-5-

ORIGINAL

109816/1701

The deposition de.? Copper base plating can be carried out by 8 * 12 min »for example 10 tain, continuous electrolysis at 60-7O ⁰ G, for example 65 ⁰ C, and at a cathode atom density of 3-6 A / dm, for example 4» 5 A / dm ₀ Preferably if the bath is stirred, for example, by stirring the air or by moving the cathode. During this time copper can be used in a thickness of 7 * 5-15 / ^. »For example 12 / *» are deposited,

Bas base metal "(a) a casting zinc-based, carrying the above mentioned copper plating" or (b) a steel-based metal, which optionally may bear one _e Kupferbasisplattierung typically either is then further treated according to the invention. Preferably _p semi-gloss Kickelplattierung is applied to the base metal such as ο the Oußstttck zinc-based, carrying the Kupferbaeisplattierung, a first layer schwefelfrelen from a ductile deposited "" The halbgiänzande nickel plating, for example, by electrolytic ischemia deposition from a bath of the tfatte-fype, a sulfamate bath, a fluoborate type bath, a chloride-free sulfate bath, a chloride-free sulfamate bath, etc., or by other processes including the decomposition of nickel carbonyl with the deposition of nickel ".

-6-

109816/1701

In a typical Watta bath that can be used according to the invention, ZoB ₀ contains the following components in aqueous solution, all values being expressed in g / l with the exception of the pH values. (The hollow chloride used is the nickel sulfate used is NiSO> .6KLO. So when we speak of nickel chloride or nickel sulphate in these tables then the hexhydrate is meant).

Table II maximum preferred component minimum 500 300 Nickel sulfate .6H ₂ C ) .200 80. 45 Nickel chloride ₆ 6 & 2 ° ³ ° 55 45 Boric acid 35 3 0.75 Semi-gloss additive 0.2 5 4.0 Electrometrisher pH 3

can be contains the following Components: ϊ preferred »7 ■ - Table III 375 IAD ORIGINAL component minimum liaximum 45 Nickel sulfamate 330 600 45 Nickel chloride .6H ₂ O 15th 60 0.75 Boric acid 35 55 ■ ψ Μ ^
4.0 ifalbglanPiftuisatz 0 3 Electrometric pH 3 5 109816/170 1 '

A typical fluoborate bath used according to the invention contains the following components:

Table IV maximum • ■ component minimum 400 preferred Nickel fluorate 250 60 300 Nickel chloride «6H ₂ 0 * 10 30th 20th Boric acid 15th 3 20th Semi-gloss additive 0.2 4th '0.75 Electrometric pH 2 3.0

As is known to those skilled in the Bern art, one can here (as elsewhere) either pure nickel fluorate or Use commercially available nickel fluorate, which contains boric acid, which stabilizes the fluoborate

A typical chloride-free sulfate bath made in accordance with the invention contains the following components:

Table V maximum preferred component minimum 500 400 Nickel sulfate _e 6Hp0 300 55 45 Boric acid 35 3 0.75 Semi-gloss additive 0.2 5 4.0
\ ~ - ξ v- Electrometric pH 3 BATH ORIGINAL ■

109816/1701

A typical chloride-free sulfamate bath, which according to the Invention can be used contains the following components:

Table VI Component Minimum Maximum preferred

Nickel sulfamate 300 600 350

Boric acid 35 55 45

Semi-gloss additive 0.2 3 * 0.75 Blectrometric pH 3 5 4.0

Of course, the baths mentioned may contain the components in amounts that fall outside the stated preferred minimum and maximum "However, normally the most satisfactory and economical work will be carried out when the components in the indicated amounts are present in the bathrooms _o

Semi-gloss additives that can be used in the first stage of the process according to the invention (using the baths of type II-VI) are Z ₀ B ₀ coumarin, butynediol, chloral hydrate, formaldehyde, piperonal, diethoxylated butynediol, bromoalhydrate, etc. ₀ The preferred half-glass The additive is coumarin, which is used in a concentration of 0.2-3 g / l * typically 0.75 g / l »

10 9 8 16/1701

The electrolytic deposition of the first, sulfur-free, ductile semi-glossy nickel plating can be carried out with the semi-gloss baths in Table H-VX using a cathode current density of 1-10 A / dm, for example 5 A / dm, at temperatures of 50-6O ⁰ G, for example 55 ⁰ O, can be carried out for 20-30 minutes, for example 25 minutes ". During this time it is possible to deposit a semi-glossy nickel on the basic metal! with a thickness of 5-40 / t ,, for example 25X4, »to be knocked down-

The semi-glossy nickel plating is essentially sulfur free, doh «that they are about $ 0.004 sulfur and typically 0.002-0.004% sulfur and sometimes only 0.0010-0.0015 # sulfur. The ductility of the semi-gloss cladding can be such that T / 2R the value of 0.5, measured with the well-known standard ~ Ghrysler-Mikromet @ r-Sess.

In accordance with the invention, preference is given to a glossy layer Nickel applied to the first nickel plating. the Results of the invention can be achieved through the use of the second layer aue g3.änaendem Niökel-mit. or without the first or semi-glossy layer can be achieved. It did work, however found »that exceptional © and undesirable © results

-ΙΟ

Ι 0 98 18 / Vi 01

in terms of long-term corrosion resistance can be obtained if both the first semi-glossy layer and the second layer of bright nickel is present »

The electrolytic deposition of bright nickel can be done by flatting from baths that contain nickel sulfate, a chloride such as ZoBo nickel chloride, a buffering agent such as Z ₀ B ₀ boric acid, and a wetting agent. Such baths include the Watts "Baths and High Chloride Baths". Other baths may contain a combination of Niokelfluoborat with Kickelsulfat and Hickelchlorid or a combination of Nlokel Bulfamat and Nickelohlorid as a source of nickel. Typical baths of the wadding type and typical high chloride-containing baths are given in Tables VII and VIII.

Table VII maximum preferred 400 300 Watts-type baths 75 60 minimum 50 40 200 65 ⁰ C 50 ⁰ C 30th 30th 38 ⁰ C

Components
Niakele sulfate,
Niokelorid
Boric acid
temperature

Mechanical stirring and / or

Air or solution pumps uswo

. ".-.-- 2.5 4 _? 5 3.5

10 9 8 1 ^{6/1701 eAD} original

Table VIII Baths preferred High chloride content Maslmum 225 component minimum 300 85 Nickel chloride β 6H ₂ O 150 1.50 - ■ 40 Nickel sulfates "6H ₂ 0 40 50 • 55 ⁰ C Boric acid * 30 - _# 65 ° E temperature * and or emotion mechanically

Air or solution pumps, etc., pH - 2.5 45 '. , 3.5

In the electrolytic baths of Tables 711 and VIII, primary nickel flavors can also be used in quantities of 0.002-0.2 g / l, for example 0.2 g / l, and secondary shine in quantities of 1-3Q g / l, for example 5 g / l * and secondary fires in quantities of 0.5-3 g / l, for example 1 g / l, should be present. Typical primary Glänser include ₀ acetyleniache compounds such as Z ₀ B ₀

i 9 ~ ■

Butynediol, dlethoxylated butyne, phenylpropiolamide or pyridinium _{compounds, such as ζ β} Β _ο quaternized pyridine derivatives, for example oil, ^ '- bis-tpyridiniuBijodldJ ^ je-lutidine ·. Typical secondary Glänzer compounds are ₀ B ₃ Sulfoeauerstofx »Z, for example, saccharin, BenzölmonoBulfonat uswo typical secondary Hilfsglänzer are ζ.B ₀ sodium allylsulfonate, Natriun-3-chloro-buten-i-Bulfonat. · *; *

-12-

BATH O.

109816/1701

BATH

The deposition of the glossy nickel plating may be carried out at temperatures of 40-60 ⁰ C, for example, 5O ⁰ G, such as 3.5 minutes at a pH of 2.5-4.5 "during 6-14, for example, 10 minutes can be carried out, wherein bright nickel plating with a thickness of 7-12 / 4, for example 10yLc, can be obtained.

According to the invention, the first Niokelpiattierung (which If necessary, however, preferably a layer of a second or metallic spot plating carries) an outer micro-cracked nickel plating old one. Thickness of at least about 0.6 / 4, and Typically 0.6-3ytc »preferably about 2 / -G, applied .

The deposition of the. outer nickel plating is preferably carried out by immersing the base, which carries this plating (con), in an electroplating bath, since (a) 120-187 g / l nickel ion »it *, (b) 110-225 g / l nickel chloride NiCl ₂ ßHgO, (o) 300-900 g / l nickel fluorate Ni (BF ^) ₂ , '(&) a primary shimmer, (e) a secondary ulancer and. (f) a Z "ma.tz ₉ consisting of a heterocyclic compound, which contains at least two nitrogen atoms in an otherwise carbocyclic single structure, is immersed _o ICypiseh® such baths are given in Table IX

10 S11S / 17Q 1.

Tab ^ lleJX

component 120 MaxdLmum bevo ^ auat M ⁺ * 110 187 150 Nicfcelchlorid _o 6H ₂ 0 300 225 "150 Mckelfluoborat 0.002. 900 450 Primary shimmer 0.1 0.4 0 _g 2 Secondary shimmer 0.1 1 0.25 additive 20 ⁰ O 0.8 0.25 temperature 65 ⁰ O 55 ⁰ O emotion mechanical and / or
Air or solution pumps

pH

The primary (KLancers * that can be used in this stage of the method according to the invention include such materials (they are in very low or relatively low concentrations a typically 0.002-0.4 g / l, for example 0 * 2 g / l present) _y which in turn result in a visible © (gloss effect or can also not result in ₀

this

von Gläaaenänen in SöEäbiimti © n © n with ₉ die

18/1

be used * to a certain Q-lance "or Koraverfeinerungseffekt erz5ielen ₀ However, when used alone, they found no specular depositions ₀ Typical primary GKLänzsr that" at this stage of the erfindühgsgemäßon method used kÖanen ₉ are z _o B _e aeetylenische Compounds - for example, butynediols, diethoxylated butynediol, phenylpropiolamide, propargyl alcohol, 3-butyn-1-ol, 2-methyl-3 '"butyne" 2 "' Ol _, or pyridinium compounds, such as Z ₀ B ₀ ciuaternied pyridine derivatives ₀ typical secondary glossers that are used in This stage of the process according to the invention can be used, are a _o B _o ^ü ulfo-oxygen compounds ₅ such as Z ₀ Bo saccharin, üFatriumbenzolmonosulfonat, Hatritumrinylsulfonat, HatritHBmetaben soldi $ ulf cast \ in * s _o

The preferred priiaären G-läazer are acetyienische compounds typischerw © isa 2 "-Butiadi © l-1 ₈ 4 Vuoä the preferred eekundäreh {Jlänzer are Sulfosau © ratoffrerbindung®n, preferably Saccharizio -.

The. Elektroplattiermigsbädero from which di® micro-cracked outer nickel plating from © seM @ d © a w @ rä @ a isann, köimen an ohejaiech © -hete ^ osvklisuhs 2u @ atgf ei ^ iadiaaghaltea, the

Sti © kst. © ffat © a © in one ans © astea earfcozyk-

18 / 1701-

triaykliach USWC Seine Usually they aind but you can monozyklischo 2,3,4 etc "contain nitrogen atoms in familiarize otherwise cyrbozyklisQhen ring structure ,, typical ring structures that can be used" are, _o B _e: pyrazole (which is 1.2 ~ diazole ), 2-IsoamidazoX (d _o i _o 1 »3 ~ isodiazole), 1,2 ₉ 3 ~ iDriazole _f 1,2,4-2riasol, pyridazine (d _o i« 1 »2-diazine), pyrimidine (d _o io 1,3-masin), pyraain (d ₍ i, 1 ₉ 4 «diazine), piperazine B-triazine (doi» 1,3 _f 5 ~ 2riazine), ae-sriazine (d _c io 1,2 _f 4- Triazine) _s v- »sriazine (d _o i _o 1,2 * >> triazine), 1 f5« pyrindine (d _o i _o 4-pyrindine), isoindazole (doio benzpyrazole) »ginnoline (d _e i ₀ 1,2 -Benzodiazine), quinazoline (d _{e 0} 1 ₉ 5-benzo «diazine), naphthyridine, pyrido (3» 4-b) pyridine _f pyrido (3 _f ab) pyridine, pyrido (4 »3 ~ b) "- pyridine _i purine ₉ hexamethylenetetramine, bis ^ pyridiniiarerbindungen

Inert substituted compounds which have the above ring structures can also be used. Typical inert substituents which may be attached to these rings are Z ₀ B ₀ inert hydrocarbon groups, typically aromatic groups such as Z ₀ B ₀ haphthyl, xylenyl, solyl , or aliphatic groups ₉ typically JÜLkylgruppeng such as ZeB ₀ methyl ₉ ethyl, propyl and butyl groupso The preferred substituents are the lower AUcylgruppisa ,? for example 3ene _e less than 5 = 6 carbon atoms

BAD OBtGlH

16V 1701

have _β These low Alkylgruppeii can coals = · atoms or on nitrogen atoms (for example 2 _e 6 Dirnethylpyrasin) available ₉ or they can Brüpkexigruppen represent the additional rings "constituting · as for example boi 1 ( '1' -lthyl © n -2 ₅ 2 '-dipyridiniiuahalogeniden as _ζ β Β β dsm dibromide or the dichloride is the case). In the heterocyclic additional compounds one or more of the nitrogen atoms may be quaternislert such _e B ₀ terosyklischen by reacting the h © compound with hydrochloric acid , hydrobromic acid sulfuric acid, etc * ₀ In the latter case, compounds which are otherwise because of their low solubility of less utility, be made considerably more soluble by the Quateraisierung "

Typical examples of compounds that can be used in accordance with the invention are: s «= triazine, u ~ triasin _f v« triazine, p ^ iäasin, pyrimidines, indole, “isobenzazole,” pyrindine _? laoindazola cinnoline quinazoline naphthyridine, pyrido * - (3 »4-b pyridine, pyrido (5 $ 2-b) -pyridine _f pyrido- (4 , 3-b) -pyridine, hexamethylaate et ramin _e piperazine, pyrazine _a 28 6 -Dimethylpyrazine

Although it is found that considerably improved results According to the invention, heterocyclic ones are obtained

used _t those in the above categories

BATH

10 9818/1701

fall, but exceptional results are achieved by the Use the following specific and exemplary Connections received:;

(I)

(II)

(III)

Hexamethylenetetramine

Pyrazine

2 _S 6-bimethylpyraaia

1.1 ^J - »ethylene ~ 2 _f 2 * ^ ipyridinium dichloride

OH,

IT

HO.

CH,

■ \

-CH-

CD

ff

(II)

108816/1701

(III)

This heteroayklisoheaZusatsverbindungen may be present in the bath in order to achieve a micro huge outer Hickelplattierung in effective amounts, and _f swar typically in amounts of 0.1-8.0 g / 1, for example, about O 25 g / lo VorEUgsweise is di © compound as quaternisisrten the compound (d _o h _o that at least one of the nitrogen atoms is quaternized) where Z ₀ B ₀ hydrochloric acid or a Eohlenviasseratoffhalogenide xiie Z ₀ B ₀ · methyl »chloride used»

The "preferred additional heterocyclic compound is ij ^ -ethylene-ajS'-dipyridinium dichloride. This product is available from California Chemical Company under the trademark "Ortho di Quat".

Typical baths beispielhaft® ,, used bsi this stage of the process of the invention include i £ _f LEVERAGING folgendesί

OFlIGmAL

109816/1701

Table X Components 120 dipyTidinium dichloria 187 150 Ni ⁺ V ...- .., no 225 150 Nickel chloride _o 6H ₂ 0 300 900 450 Nickel fluorate 0 * 002
φ 0.4 0.2 Primary (KLänser,
ZoBo butynediol 0.1 i 0.25 Secondary Giancer ₉
KoBo saccharin O ₈ I. 0.8 0.25 Addition t SSoBo

XI

Components Minimum M ^ imum "bevorsupj 120 187 .. 150 Nickel chloride _o 6Hg0 110 225 150 Niokelfluoborat 300 900 450 Primary Grazer
ZoBo butynediol O ₅ OOg 0 _s 4 0 ₉ 2. Secondary glasses
ZcB ₀ saccharin 0.1 1 0 ₉ 25 Additional connection
SoBö hexamethylene
tetramine .0.1 0.8 0.25

109818/1701

Components 120 maximum prefers 110 18? 150 fflekelchlorid _o 6Hg0 300 225 150 üTickal fluoborate 0.002 900 450 Primary shimmer
ZoBo butynediol 0.1 0.4 0.2 Secondary G-lancer
ZoBo saccharin 0.1 t- 0.25 Additional connection
Z ₉ Bo Pyraziß 0.8 0.25

The deposition of the microcracked nickel precipitate can bsi 40-60 ⁰ C, 50 ⁰ beispielswQise O, at a pH iron 2 * 5-4o5, for example 3 $ 5 _f during 2-4 min, for example 2 minutes, erfolgeng said sine shiny with Nickelplattierwng a thickness of at least about OgS ^ H. $ preferably 9 e.g. 1Zt _- ,, eraielen _o

It is a special Merkiaal the deposited in this way ITickelplattierung that it was characterized by a micro-cracked © Struktixr If, for example, in a thickness of at least about 0.6 j ** _r and Virtue "weiae _Ο? 6 · »3 ^, S ₀ Bo 1 jj ^ _g is then found that the precipitation is at least 10% / cm, as a precaution! 00 = 600 parts / cm ₉ and typically about

109816/1701

250 cracks / cm contained The micro-crack pattern allows for a glossy to mirror-glossy fickle plating with the specified thickness, which is characterized by a high resistance to corrosion _{or similar}

Is is a feature of this outer nickel plating that it can be mirror-shiny ^ if si © is deposited in the above manner _s and that it allows the achievement of a high leveled specular surface, which is characterized in particular by their assets "that it can accommodate a Ghromplattierung and that it allows the creation of a plated object that has an unexpected degree of corrosion resistance.

Chromium can be deposited on the shiny nodule plating according to the invention by means of deposition on an ear plating bath in the following syntax set out in table SIII

Ü3äü3S • Ϊ1 b ^ ö ^ uj -22- 250 400 250 9 - 1 2.5 4.0 '2.5 ORIGINAL - _ * BATH D9816 / 17C

₂₂ ".1521117

The sulfate can be introduced "in the form of sodium sulfate or Sohwefel" satire In Chrosnplattierungsbad other ingredients · may be present, such as 2 "B _e such ingredients that make dae Bad selbstregulierand or high. Deposition rates allow »Typical such other components in the bath are strontium ions (which are issued in the form of strontium sulfate or strontium sulfate) or SiFg == *" ₉ which can be issued in the form of KalJUaasllicofluorid «,

The chromium plating can © rfindungsgemäße bsi 45 "-55 ° O, wherein" play facing © 5O ⁰ C during 2-4 ₉ Sain _9, for example, 5 min / dm at a Eathodenstromdichte of 12-20 A, for example 14 A / dm @ executed expectant n _e This typically means that a chromium plate with a thickness can be achieved

Ss is a "special highlight & es Merksaal of the invention terstollen products «that they face the infiltrations a corrosive atmosphere with an exceptional one have been found to be highly resistant for a long time, for example

an invented GeisSi olsrom-plated product orrosioasbediBgimgen ^ as sJ * in the OASS-ICeet or in the G © »© clk®t ©« »Tegt, we are subject to this © new products

109818/1701

■■ "" ■ -23- "1521117

practically no visible corrosion on the volume for three cycles this test shows “Typical bright chrome plate protrusions show a remarkable one even under the most favorable conditions Degree of corrosion after the first cycle of Corrodkote-

The invention is explained in more detail with the aid of the following examples « All parts bind expressed by weight * eof em nothing else is stated o

Examples

, In these examples, unless otherwise indicated _s plating on a steel plate with a thickness of about 1, 5, and carried out with a size of 10 sam χ 15 cm, consisted of the soft alloy steel 1010th

In all Pällen, unless otherwise specified, the steel plate before -was d © r treatment to remove Rostfleeken _P grease, oil and the like "in the usual V / else cleaned before treatment was applied to the steel no copper

Yienn a haXbglänsensä © Nlckelplattierung applied to the 8auh @? E steel plate \ raräe _{9 then} it was made of sinem

BATH

109816/1701

A nickel plating bath deposited »which contained 45 g / l Hiekel chloride ο6H ₂ O, 300 g / l nickel sulfate .6H ₃ O, 45 g / l boric acid and 0.2 g / l • 1,4 ~ butyne, diol, the electrometric pH at was held approximately 3 "5" / The plating was coated with a Kathodenstromdiehte of 6 a / dm at 55 ⁰ C for 35 rain executed, whereby a precipitate was obtained from a nickel halbglünzenden of 30yii ₀

If, in the examples, the code is a bright nickel strike, then this was obtained by electrolytic deposition from a plating _{bath containing 60 g / l nickel chloride e} 6H ₂ 0, 300 g / l nickel bilfate, 6HgO, 40 g / l boric acid and O ₈ 2 g / l butyne diol as the primary Giänaer, 1 g / l of saccharin as eekundären ölänzer and 1 g / l Butindlol-monosulfonate as a secondary Help "Glänzer contained the bath was during 10 min lasting deposition at 55 ⁰ O at a pH of 3» 5 held, whereby a nickel plating with a thickness of 7 »5 / * t was achieved,

The electrodeposition of the micro-sparse silver plating according to the invention was carried out in these examples. a bath carried out ₉ the 150 g / l nickel chloride _o 6Hg0, 450 g / l ITickelfluorboratp 0 ^ 2 g / l "butynediol as a primary GKUtaeer, ₀ 25 g / l Saccliariii as a s © kimaer G-läaser unit the Ib of the following -

-816/1701

angegebenen- amounts of heterocyclic compound additive contained "The bathroom was during Plattierungsaeit on a elektrometrlschen pH of 4 and a temperature of 55 ⁰ C supported * th ₀ The plating was changed as indicated in the sequence to achieve the desired thickness of plating"

If there is talk of a decorative chrome plating "then it was obtained by deposition from a bath" since 250 g / l chromic acid and 25 g / l sulfates, which were added as sulfuric acid, would contain the deposition for 1.25 min at a cathode current density of 21 _s 6 A / dm made it possible to obtain a decorative chrome plating with a thickness of

example 1

In this comparative example, an ® was applied to the metal plate Bright nokel plating and then a chrome plating applied »

Example 2

In this example "comprising conducting explained dea © rfindungsgeraäßen method, the Stamäardatsiilplatt © © .werde with a lananickelplattierung with microcracked Ui © k @ l (2 min continuous deposition in a bath containing at elBem.QeihaXt O ₉ 25 g / 1

-26

109816/1701 bad original

1521117

Hexamethylenetetramine) and then plated with chrome *

example 3

In this comparison example "the standerdatahlplatte with bright nickel and then plated with chrome,

Example 4

In this example? which is a comparison fairy example, mirde the standard steel plate with semi-polished nickel »old glossy nickel and plated with chrome.

Example 5

In this example, which illustrates the process of the invention, the standard steel plate with semi-bright nickel, plated nickel microcracked (2 min continuous deposition in a bath containing 0 _# 25 g / l hexamethylenetetramine) and then with chromium was

Example 6

In this example, which is a comparative example » became the standard steel plate with semi-gloss nickel and plated with chrome

109816/1701

Example 7 -

In this example, which explains the method according to the invention, the standard steel plate is plated with semi-bright nickel, with micro-cracked nickel and with chrome. The micro-cracked nickel was deposited from a bath, which O _e 25 g / 1 Isi ^ -Athylea. 2 _f 2 \ - <5'ipyridinium dichloride contained. The deposition lasted 2 minutes, whereby a plating with a thickness of 1 »O / t was obtained"

Each of the steel plates of these examples was subjected to the Stondard-CASS test referred to above. The reading was carried out so that each plate ₉ for the specified time was kept under Xestbedingungen was investigated whereupon the surface of the base metal for corrosion _o In Examples 6 and 7 was used test of Corrodkote test,

example

1 (control)

5 (control)

4 (control)

duration

22 hours 107 hours 22 ötimden 22 hours

Remarks

100 rust spots nothing

50 EostfXeek © Z Rostfleeks

109Ö16 / 17Ö1

ORIGINAL BATHROOM

An examination of the specimens on the bath of cycles of the specified tests showed ρ that the control samples in Examples 1, 3 and _t 4 were heavily corroded. 6 All other samples showed practically no corrosion. The plates of Examples 2, 5 and 7 showed high corrosion resistance under the test conditions and a minimal number of surface defects. The plate of Example 5 showed a completely exceptional corrosion resistance ο In fact, at the end of the rigorous test it was just as shiny as before the test «

A comparison of example 4 (this example is typical for a double cap chrome plating according to the state of the art) Examples 2 * 5 and 7 (which use the process according to the invention explain) clearly shows the superiority of the method according to the invention.

It can be seen from Table XIII that the process according to the invention allows a chrome-plated product to be obtained, which is characterized by an unexpectedly high corrosion resistance. It can be seen that the panels passing through the method according to the invention in a preferred embodiment (Example 2) were obtained ^ are particularly good.

»29-

109816/1701 ^eAD

Claims (1)

29- - 1621.U7, Godfather η ta K ₁ a checked he Ie method of electrolyte laughing deposition of a Mlokeischicht, which is characterized by Saa capacity for receiving a C roraplattierung having a high corrosion resistance ,, characterized gekennse leans _f that b on a base metal, a first sulfur-containing ölanssniokelplattierung ^ aufDTlii ^, and that then at least 0, 6m. an external micro-cracked nickel plating electrolytically deposited from a bath; that contains about .. ■ -, ". ,,"_; 120-187 g / l Hi ⁺⁺ _e 110-125 g / l HiC! l _2O 6H ₂ 0 and 300-900 g / l 3ii (BP ₄ ) ₂ . The method of claim? * Characterized in that the bath for dl © outer Mckelplattierung containing an effective amount of a heterocyclic Additives food & sverbindung that mlndestene two nitrogen atoms in an otherwise carbocyclic ring structure contains ₀ 5 »method NaOH claim 2, dadur ö hg β k ® η η - _r is characterized that as heterosyklische Zusatsverbindung hexamethylenetetramine" Biperasin "Fyrazin» pyrazine or Ivi ^ -ithylen ^^ ' is used. : © AD ORtOiNAL 10 9 8 16/1701 4β method according to claim J, dadurehgekenn « draws that as a heterocyclic additional compound. is used _o ο method according to one of the preceding, specifications, characterized by 'that the first one was a sulfur-free, semi-glossy one Nickel plating is deposited " 6 »Method according to one of claims 1 to 4» thereby characterized in that the first Ulekelplattierung deposited a glossy Nxekelplate ο Method according to one of claims 1 to 4, characterized characterized in that the first nickel plating a sulfur-free, semi-glossy mckel plating and a layer of shiny nickel plating includes 8 "Method according to one of claims 2 to 1, characterized in that the bath for the electrolytic deposition of the outer, micro-cracked nickel plating 120-187 g / l JiI ⁺ *, 110-225 g / l NiCl ₂ <> 6H ₂ 0 , 150-450 g / l Ki (BF ^) ₂ , © inen primary gloss and a 'secondary oil dancer contain ^ - 1 f09816 / 1701 Process according to Claim 8 »characterized in that the additional heterocyclic compound is used in an amount of Q _P 1-0.8 g / l. BATH 109816/1701