DE1621326A1 - Process for non-electrical plating of non-conductive objects - Google Patents

Description

45 414

George C. Reinhard, 16682 Robert JJane, Huntington Beach, California and

Michael W. O'Mara, 11209 Stamy Road, Whittier, California, United States

Process for the non-electrical plating of non-conductive objects

The invention relates to the plating of metals onto the surface of articles without application of electricity and in particular of the non-electrical plating of metals such as kickel and cobalt with- ' means of chemical reduction of the metal ions to the pure metal or metal element in question, with hypophosphite or hypophosphate salt is used as a reducing anion will.

Because the reaction is catalyzed by certain metals triggered, it is known as catalytic plating. Since also the deposited or precipitated

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'(621326

Metals also act as catalysts for the reaction, one speaks more precisely of autocatalytic Plating.

Some of the earliest patents relating to this process are U.S. Patents 2,532,283 and US Pat 2,532,284 by A. Brenner and Grace Ridell. Since these first patent specifications, numerous other patent specifications were published and further contributions were made, so this method is highly developed nowadays.

Srots of the high level of development of the known processes the requirements are becoming higher and higher in order to reduce the limitations of this method. Accordingly Suggestions were made to improve some special features, For example, to improve efficiency, use faster plating speeds at a given To achieve temperature, plating sufficiently fast to enable at low temperatures and to improve deformability and adhesion, etc.

Originally there were methods of plating metals which are inherently catalytic or for one Catalytic converters have been developed, whereby even non-catalytic non-metals such as glass, ceramics, organic substances, which can be natural as well as plastics., in a similar way for cataly-

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transmitters have been made receptive or receptive,

and finally a catalytic remanufacturing cladding
to enable production by coating it with a PiIm made of a catalytic metal such as palladium or otherwise preparing it.

The processing of organic base or carrier materials such as plastics, synthetic resins, polymeric materials in general, Fylon, etc. makes it more and more urgent to create further improvements to the "known process" Even with the not fully developed processes and ineffective methods, plastic bodies of various kinds were made and for a variety of uses that have been produced in known manner by injection molding, Vakuuajguß, die casting and other casting methods, etc., with metals _s plated so AEAS this body Off = · ropes, in use in the utility, decorative? in the beauty etc .'alle types of metals such as silver soid ₉ copper, brass, chromium, etc. mimic. Due to the natural properties of the plastics, and their relatively low cost Sest ^ hung including economic production v / hereby ground advantages over such objects orsielt made entirely of the metals consist that by the above procedures mentioned above can be imitated.

The acrylonitrile-butadiene-styrene copolymer-Kunststoffj the tiird hereinafter simply called IBS _s is commercially available

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and is particularly preferred because it is a solid, dense, impact-resistant type of polymer by practical molding methods can be shaped and deformed into large volume articles and is strong in the market is gaining ground to metals and other plastics for numerous uses and applications substitute.

There is already a need for such articles that are made from materials such as ABS plastics, however became the full application or the suggestion for full application of these plastics because of the lack of perfection an effective, reliable, quick and effective plating process has hitherto been prevented.

In contrast to the plating of metals and heat-resistant non-metals, the polymeric plastics are organic or semi-organic nature (polymeric Hydrocarbons, hydrofluorocarbons, silicones) are generally much more sensitive to heat, so that their Processing is severely limited, making it impossible or impractical to use many of the solutions, methods, and techniques to use for their processing, which can be used for metals and heat-resistant light metals. The dissolving effect of the heat is a particularly important one Point of view. At temperatures that are far below those at which metals show signs of dissolution or transformation show arise in plastics and

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Synthetic resins have such effects as softening and destruction. This is not only possible at elevated temperatures or observed under dry heat conditions, but even at temperatures where water is boiling, and even in humid conditions. Accordingly, as general condition, although this is not always applicable, that plating processes do not apply higher temperatures than 60 ° C and of course as close as possible to be carried out at room temperature of about 21 ° C.

Generally speaking, it is the object of the invention therein to improve the known methods in such a way that taking these into account through the material properties The conditions set for the plastics in a simple and effective way to cate the plastics with Metal, etc. aggXieh is.

More precisely, it is the object of the invention to create the possibility of using certain catalytic oil-hypophosphite plating baths to precipitate electrically conductive deposits of metal phosphorus, which is a characteristic precipitate from such hypophosphite-reduced reactions, and to precipitate the metal phosphorus at isolating speeds and at all deposit temperatures and soalt particular a flat animals in aisärigea -temperatures to "rmSgllöhen. This rapid plating takes place at temperatures between at least normal

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Rare temperature of about 21 ° C to at least through Plastics in general and in particular acrylonitrile butadiene styrene plastic: fle, which are generally referred to as ABS plastics, set upper limit temperature, which is generally about 60 ° 0.

Another object of the invention is to provide improved stability of the plating solution so that it can be used over long periods of time, with only the reagents or reaction means having to be used accordingly. It is Aufgab® the Erfindisng ₉ pH-control, so that it is not necessary toäiafig ziasugeben alkali to adjust the pH value to hold the wheel to the desired &, which is usually necessary in bsstiiaister örensen an automatic to provide to to neutralize the reaction acid which normally forms in the reaction of the hypoplaospbites.

The stand of fecbnik shows how the "pretreatment, conditioning and preparation of the objects to be plated should be carried out. It can be any Processes are used that make the plastic or non-metallic object catalytically active, including the deposition of metal from the metal hypophosphite or cataly ti see to make reduction baths possible.

BATH ORIGINAL

A careful study of the prior art clearly shows that heretofore generally common inexpensive salts of nickel and sulfur chloride have been used to make up the bath and thereby provide the nickel required for air plating.

The original work of Brenner and Ridell shows that particular types of ions, other than SO, and Cl, were added for specific purposes and adhered, proving their importance. For example, alkali salts of weak organic acids create a buffer effect for maintaining the pH value within certain limits in the acidic pH value range. This is to avoid a rapid drop in pH below a certain value, below. the plating speed is greatly reduced or the plating is prevented entirely. Other organic salts were those which form complexes with nickel and belong to the group of reactants such as hydroxyacetic acid, lactic acid, citric acid or tartaric acid. This was carried out in such a way that, if an addition of alkali was necessary to raise the pH to the desired value, which, as recommended, resulted in a local neutralization of the insoluble basic salt or hydroxide, which is unfavorable for the stability of the bath, is not formed. These salts, which are formed from the weak acids contained in them, have buffer properties in addition to their complex properties.

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The work of Gutzeit et al determined the puncture of other organic anions, which are "accelerating" act on the reaction, by which is meant that they contribute to the speed of the reaction and thus the Increase plating speed.

Refer other contributions to the known art relies on the chemical additions, usually cations, in immeasurable quantities, thereby causing stabilization becomes, and resort to mosquito carbonate additions to acidic Baths to replace the used Mekel and at the same time to increase the pH value as desired without having to enter foreign ions into the bath.

So far seemed to have the opposite effect inorganic ions, especially SO. and Cl, valued without expressly excluding them, which is believed to produce the best results to be able to.

A gate treatment is required in order to avoid non-metals and non-catalytic materials for the reaction of the applied solution, at least at the beginning of the treatment and until the autocatalysis has started, catalytically do.

This is done during the pretreatment by applying a thin, often imperceptible, invisible adhesive

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tend * film made of pure palladium, which, since it is a catalyst that triggers reduction, which after Fiekel or cobalt has been deposited, autocatalytically is continued.

This pretreatment and preparation generally requires that the underlay material is cleaned and conditioned or prepared in a suitable manner so that the Palladium faster and more complete from the material the document is taken up and adheres to it, since the thoroughness of this application of the palladium is the complete success or partial failure of all subsequent chemical and electrical metal deposits.

The pretreatment depends entirely on the material to be processed. Pali's organic polymeric materials, including ABS plastics, are first pretreated to remove dirt, oil, grease and other foreign matter using any alkaline detergent. This pretreatment is followed by a weak acid rinse to neutralize the alkali cleaning agent. Subsequently, the article by wet oxidation in a bath of chromic acid mixture is generally at a maximum of 60 ⁰ C, or chemically matted geltet, whereupon the article in response to: .ce g £ Iltig "n rinsing to be pretreated enough ER-?

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seems to be subjected to subsequent treatment so that its surface can receive an adhesive palladium film applied to it. Methods working with peculiar or non-peculiar mixtures generally consist of using a Film made of a strong reducing agent, which is able to dissolve palladium salts into their individual elements to be disassembled, to be absorbed by the cleaned, etched or abraded workpiece surface. Accordingly becomes elemental or pure palladium when the workpiece is immersed in the palladium salt solution in the form of a thin, often invisible and even monomolecular Elm is deposited on the workpiece.

As noted for the first time by Brenner and Ridell, rain Ammonia ions the reaction especially in the more alkaline or based pH ranges, while others Cations like barium and magnesium influence the speed of the reaction in a better or worse sense.

The need to buffer substances from the salt of a weak Provide acid and / or means for generating complex compounds when baths operate in the acid range and in these alkali supplements are entered in order to periodically adjust the pH value from time to time, is not an unconditional requirement and important and am best only desirable when the bathroom in one

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ammonia-containing medium is operated, is constant in the alkaline pH range and the pH is adjusted with ammonia and, better still, by adding an excess of ammonia, as proposed here. This is the case if the numerous compounds of the Mckel-ammonia complex compounds are buffering agents in the alkaline range of the pH scale. The critical pH value at which the basic compounds or Hickel hydroxides become insoluble is not within the pH value limits for working with this solution. Within these limits, the complexes of nickel-ammonia compounds prevent insoluble basic compounds or hydroxides from forming, despite the alkaline nature of the bath. The excess of free ammonia ensures a satisfactory pH value for a long time, which reduces the risk of an accidental drop in the pH value below the pH value desired for a good job. According to the present invention, therefore, it is unnecessary to select the anion taking each of these punctures into account; rather, it can be selected primarily from an economic point of view, provided that inorganic anions, especially SO ₄ and Cl anions, are avoided.

However, examples of plating baths consistent with the features disclosed and taught herein are not limited to these are the following:

ORIGINAL BATHROOM

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example 1

A solution with traces of up to (preferably) 7.5 g Nickel / 1 at a pH of at least 8 of nickel-ammonia-hypaphosphite, preferably with a Excess of ammonia hydroxide was produced.

Example 2

A solution with traces of up to (preferably) 7.5 g nickel / l at a pH value of at least 8 from nickel ammonia glycolate, which was preferably made with an excess of ammonia hydroxide.

In Example 1, no additional anions were added. Only a portion of hypophosphite in connection with Hiekel has been added as an anion in an amount sufficient to reduce not more than 50 $> of the nickel on a theoretical basis. This is only wn about 1/3 of the amount necessary to reduce all of the nickel in practice.

This is an ideal ratio of hypophosphite to nickel to get the bath to work initially because it when the bathroom is so extremely activated or "accelerated", ratsaai is the concentration of the hypophosphites in the beginning nlcbt mater adding more aggregates to increase. Ba the activity of these solutions in alkaline media by the absolute concentration of the hypophosphitea or

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BATH ORIGINAL

the ratio between hypophosphite and nickel increased and is stimulated or promoted, one contributes high hypophosphite concentration excessive to activity and makes it so reactive that the stability of the bath is canceled.

However, if the hypophosphite is applied faster than the nickel during operation, the resultant does Relationship between hypophosphite and nickel the solution even more stable. The hypophosphite must of course be refilled according to its consumption in order to be effective Ensure consumption of nickel. Such additions are made from time to time in the form of an alkali or aluminum oxide salt and made in an amount that will restore the ratio between hypophosphite and nickel to its original value brings, but does not exceed the original ratio, thereby undesirably increasing the stability the solution would be affected.

In the second embodiment example 2 ₉ hypophosphite, since it is in the? used nickel compound is not available; Be added at the beginning. This is done like this; that at the beginning the same molar ratio γόη 1 mol nickel to 1 mol hypophosphate © ug d @ ® already mentioned Sr and the stability of the Lö'srag vosfeas - & @ n «■ From the likewise ob © 33. © already stated "reason is the SaeMillXQ» ron ^ hypophosphite in OT i @ © © lb 23rd allgaistlaan Weis® w && tegstl ^ tii Ast u & cä, ¥ ®i @ © wi © ia? @s>

BATH ORIGINAL

Binding described with Example 1 carried out.

If Dian, one of the two baths described and, in the case of Example 2 with an additive, ammonia hypophosphite is used in the specified amount to effect the reduction, the plating takes place quickly at a room temperature of about 21 ^° C. Bas plating makes itself felt by the development of at the reaction formed gas on the surface of the catalyzing article and the visually noticeable change in appearance, which is noticeable when lightly colored plastic bodies are plated), since the article quickly darkens and becomes opaque on its surface and gradually acquires metallic luster and appearance .

At higher temperatures the speed of the Eeatetioa rad deposition of metal increases very quickly, which etemfeterieeb, "for all © solutions of the kind described is ο with seupersturge from 37 ° to 44 ⁰ O is the plateau? -

ity of an order of magnitude that about 0.013 'S-fcd. Metal is deposited. This is it dia most practical "aad optimal speed for that

© !! mean the average

fte Eiaastsitoi ^ Q ä®s? fut © ll @ a _s © r follows the reaction Ablsgei ^ sag s® ncbaollj, iaB si © impractical for the

ma99n / iRoi ^BAD

Electroplating is pretreated plastics. At even higher temperatures, which come close to those normally used (more than 93 ^° C.), the rate of reaction and deposition is so great that, because of the instability associated with this, they should not be used with the exception of certain special applications , without reducing the rate of deposition, either by reducing the ratio between hypophosphite and nickel or by adding retardants such as those which are precisely to be avoided by the present invention and which characterize other slower working baths used heretofore, which in many ways with the proposed Bathrooms are identical except for this one point.

In attempts so far to improve the method first proposed by Brenner and Ridell one has to deal with additives like the activators or "accelerators" suggested by Gutzeit et al. tried to remedy. In contrast, the However, the present invention does not improve the solution or the bath by means of aggregates or by Complicate the composition of the bath, but rather by simplifying the process for the reaction basic ions necessary or formed during the reaction; in particular, this is done by avoiding such Ions in the bathroom, which are particularly inhibitory to the reaction

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act (i.e. SO. and Cl) and which have always been used up to now have been achieved.

The level of the pH value of the solution or the bath is automatically maintained for a long time if an excess of ammonia is used and is proportional to the size of the excess, which can be varied within wide limits. The acid formed in the reaction, characteristic of these nickel-hypophosphite plating solutions, is neutralized as soon as it is formed, without causing a reduction in the pH until the excess ammonia has been consumed. Thereafter, the change in the pH value does not take place abruptly, but gradually, since the complex nickel compound acts as a buffer, which can only reduce the pH value gradually with the removal of ammonia bound in the complex compound by the acid formed during the reaction, wherein the nickel compound is converted from a higher complex compound to a lower complex compound. This gives rise to a progressive chromatic V _e of the solution ränderung from dark blue complex with maximum nickel compound on the variations of a greenish blue, bluish green and finally to a green of lower Nicktlwrbindung complex. Thus, the color change is a visual display of the change in the pH value, which the operator can always determine without any special examinations, and ultimately a control practice

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or control experience developed that is reliable and secure. If the composition of the bath is visual is monitored, it is preferable to use the dark blue one caused by the maximum complex Niekel compound Coloring work. As soon as there is a greenish tinge results, preparations should be made to add additional excess ammonia to the bath.

So far, the main objection to working with has been alkaline baths containing ammonia, even if no large excess of ammonia is provided and, in particular, if there was an excess of ammonia, in that an uneconomical loss of ammonia by volatilizing it into the atmosphere associated with a unhealthy, irritating to human organs, uncomfortable and undesirable atmosphere because of the strong Volatility of ammonia would arise.

This is understandable because the solutions or baths heretofore proposed have been so inactive, and consequently so slow in plating speed, that they do not produce plating at room temperature or operate so slowly that they are impractical and do not develop practical plating speeds, if not at least one temperature of 71 ⁰ O was applied. Usually temperatures between 87 ° and 99 ° C were necessary to achieve practical plating speeds. With these

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Temperatures, ammonia is so volatile that it very quickly out of the solution or the bath into the surrounding area The atmosphere evaporates, and even the double salt of the complex compound of nickel is dissolved and removed with which it was associated. This makes the pH much faster than just under the influence of the acid formed in the reaction is reduced. In addition, there is an economically noticeable loss of ammonia by volatilizing it into the atmosphere and the atmosphere is accordingly contaminated.

These disadvantages have also been found in the proposed solutions occur if they were to be used at the higher temperatures given above.

In the operation of these non-electric hypophosphite reducing baths, the phosphite anion is formed as a reaction product and its concentration increases in proportion to the amount of nickel deposited by plating to. In the proposed baths, this accumulating by-product does not or does not affect the solution inhibits their effectiveness nods if the replenishing amount of the nickel precipitated by plating is not exceeds three times the original nickel concentration of 7.5 g / l. The slight decrease that occurs in the process the plating speed is easily compensated for by increasing the temperature, for which purpose a sufficiently large SpislrauiSL is provided, or by

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BATH ORIGINAL

Increase in the absolute concentration of hypophosphite,

According to the inventors, this flexibility is due to it attributable to the fact that no reaction-inhibiting, externally added inorganic anions, in particular, in the bath SO, - and Cl anions, are provided and that In the ammonia-containing medium, ammonia cations predominate, which is an essential feature of this invention.

It should also be noted that the improved results described here with the bath according to Example 2 also can then be achieved when the production of the nickel-ammonia-hydroxyacetate The glycolic acid used is the 70% commercial technical acid and not the one Acid purity which burner as essential to achieve the activity of its solutions indicating that in the best cases, as indicated, not as active were like the solutions according to the present invention *

In the manufacture of double salts of ammonia complex compounds it is customary to make these from the normal salt, which is stoichiometric by reacting Proportions of nickel and aniones either by ion exchange or by reaction of the acid with a suitable basic connection of the Hickels such as Nickel hydroxide, carbonate, etc. is formed, a quantity of ammonia hydroxide being added to the normal salt is to the complex compound of the described

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Degree and the type described.

It was found, however, that the double ammonia-nickel complex compound of the composition and type described directly by adding one of the amount of normal Ammonia salt equivalent amount of a Niekel base material how nickel carbonate can be made into an ammonia-containing solution of the normal ammonia salt, whereby an unexpected reaction takes place very quickly and certainly in such a way that the reaction comes to an end. the Reaction is simplified even at moderate heat when nickel carbonate is the base material, being a fast one Excretion of carbon dioxide accompanies the reaction. In the case of the exemplary embodiments described, those used are Ammonium or ammonia salts, hypophosphite or hydroacetate.

It was found that the reaction described above can be used to fill the bath with additional nickel ions and is an economical method forms to achieve this and at the same time undesirable Switching off anions or preventing the addition of unwanted anions that are already present. When a Supplement the already made from normal ammonia salt in ammonia-containing Medium-composed solution by simply adding the predetermined amount of the nickel base material, preferably of nickel carbonate, in the form of a water slurry or by sieving or other suitable

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Way while stirring the bath and at If a slightly elevated temperature is to be carried out, the nickel is a perfect solution quickly and without difficulty a. This regeneration is preferably carried out when no workpieces are being plated.

This result is quite unexpected because it is well known that insoluble Mckel base materials and Mckel base compounds react directly with acid and form a soluble salt, but generally in alkaline media remain inert and inactive and insoluble. Accordingly, the proposal is to use the double ammonia complex nickel compounds of the type described above both for the original bath and for refilling of nickel is another desirable improvement and advance over the prior art of the technique.

The invention is not limited to the "compounds described above." limited, since other organic acids can also be used, only hydroxyacetates were used in the description chosen because these are typical compounds and preferred because they are e.g. Currently economically advantageous are, especially in the commercially available 70 # technical form that has been determined to be suitable. This solution is in the present case in no way from the normally usual reasons (namely because of the well-known property of complex nickel compounds in the pH-WerA

BATH ORIGINAL

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form rich below pH = 8). According to the invention is not worked in this pH range, since the plating at low temperatures is insufficient and too slow in this pH value range.

When plating a non-conductive object that then to receive a second plating by electrolytic process, it is necessary to the surface of the dielectric deposit a quantity of conductive material in sufficient thickness to be deposited on it Layer to be able to perform a satisfactory electroplating. When the deposit or pre-plating is sufficient, the following electroplating can be performed without affecting the electric current too great resistance to bend, which prevents burning of the workpiece and at the same time a satisfactory electrolytic plating speed is maintained.

In practical trials it was possible for a period of six months using one solution of the type described to carry out a uniform production of well-plated objects by using the Bath a film or coating of a conductive metal-phosphorus mixture on the order of thickness 0.508 / U (5f08.10 ~ ^ mm) from the bath on the objects is deposited. This is with an immersion time of only 5 minutes in the catalytic solution heated to 43 ° C with improved activity of the kind described above

reached wor ^ _{2 Q ,, g} g _A BAD ORIGINAL

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The reject (1 ^) was abnormally low compared to other baths (for which a reject of only 10 96 is designated as ⁿ good ^w ) and the production rate was precisely adhered to.

In addition, solutions were used daily under severe production conditions that remained stable for long periods of time and repeatedly replenished and regenerated to an equivalent of three times the original nickel concentration became.

There were solutions from plating to practically exhaustion their nickel content (up to 95 #) used what Visually detectable by the low color value of the solution in comparison with the strongly colored Niekel complex compound was because the color of the bath is a suitable means of assessing the amount of nickel it contains.

Plating until the nickel content of the Bath leads to better economy if the bath is to be replaced, as this makes it possible to to remove virtually all of the usable expensive nickel from the bath before discarding the bath.

Claims

, BAD ORlßiNAL

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Claims (18)

Claims; 1. A method for the non-electrical plating of metals such as nickel on cleaned surfaces of a practically non-conductive material that has been pretreated by means of catalytic coating, characterized in that the cleaned pretreated material is essentially made of nickel, ammonium or ammonia and hypophosphite wherein the mixture comprises ions of other salts than those containing chlorine or sulfur, existing mixture is treated at a! temperature between 21 ° and 6Q ⁰ C, a pH of 8 or greater. 2. The method according to claim 1, characterized in that the ions by dissolving or decomposing a double Ammonia-idypophosphite complex compound of nickel is formed will. 3. Terfahren according to claim 1, characterized in that the nickel ions by reacting a basic nickel compound from the group of nickel carbonate and nickel hydro3öFd be formed with ammonia hypophosphite. 4. Y @ r £ ahr © n according to claim 1, characterized in that the mixture reacts with a basic nickel compound from the group liskel'aarböiaat sand nickel hydroxide asit within the mixture at ei & ess pE value BATH 10982 071S 9 4 is regenerated by at least 8, with nickel in the molar equivalent to Hypophospb.it is added. 5. The method according to one or more of claims 1 to 4, characterized in that the plating solution with ions of a metal and hypophosphite ions of compounds, which contain neither chlorine nor sulfur, is formed and has a pH value of at least 8. 6. The method according to claim 5, characterized in that the metal ions by reaction of the double ameonia complex compound of nickel to nickel-araaonia-hypophosphite be generated. 7 · The method according to claim 5, characterized in that the metal ions by reaction of a nickel base compound from the group of nickel carbonate and nickel hydroxide generated with ammonia salt of an organic acid such as glycolate will. 8. The method according to claim 5, characterized in that the metal ions in the form of the double ammonia complex compound of nickel can be used. 9. The method according to claim 8, characterized in that the double Aanoniakkomplexverbindungen the nickel Nickel-ammonia salt is an organic acid. BATH ORIGINAL 109820/1594 10. The method according to claim 8, characterized in that the double ammonia complex compound of nickel Is nickel aramonia hydroxyacetate. 11. The method according to one or more of claims 1 to 10, characterized in that the nickel ions the Ions of a double ammonia salt of nickel are and have a pH of at least 8 in the solution an excess of ammonia is maintained, the mixture being a visual indication of the decrease in the pH value below 8, which is proportional to the nickel content remaining in the solution. 12. The method according to one or more of claims 1 to 11, characterized in that a) a solution is prepared, initially essentially consists of nickel and ammonia cations and hypophosphite anions and practically no Cl and Contains SO anions, b) this solution is maintained in a temperature range of 21 ° to 60 ⁰ C, c) an amount of ammonia hydroxide is added to this solution which is in excess over that for developing a dark blue color characteristic, the color being an indication of that The presence of a maximum required amount of ammonia-nickel complex compound is, BAD ORIGINAL 1 09820/1594 d) the cleaned and pretreated objects are immersed in this solution for a time sufficient to form a sufficiently thick coating of an electrically conductive metal-phosphorus mixture of the order of 5.08 to 0.508 / U (5.08. 10 ^mm ) on the objects, e) the solution from time to time according to the When consumption of the hypophosphite occurs, additional hypophosphite is added, which is required to prevent the precipitation of metal from the plating Solution and thus continue plating, f) the solution from time to time according to the neutralization of the excess of ammonia due to the acid formed in the reaction and in agreement with the corresponding reduction in the pH value, which is caused by the visual color change of the solution from dark blue to green, a further excess of ammonia is added to to keep the solution at the desired pH value for further working hours and g) in the solution from time to time with the loss due to precipitated Mek @ l ₉ which is noticeably refilled due to the reduction in the color intensity of the solution maofet _s nickel, which is selected from the group, the Uickel-Amaeniak-HypophosphitT Niekelhydroxyd and Uiekelearbonat contains. BATH 109820/1594 13. The method according to claim 12, characterized in that that the solution initially prepared is essentially nickel and ammonia cations in the form of a double Ammonia-Niekel's salt contains other anions than chlorine and sulfur, the anion preferably that of an organic acid and wherein the solution additionally contains essentially hypophosphite ions. 14. The method according to claim 12 or 13, characterized in that that the nickel-ammonia and hypophosphite ions produced by a Niekel ammonia hypophosphite will. 15. The method according to claim 13 »characterized in that that the nickel and ammonia ions from the double nickel-ammonia salt of an organic acid and the Hypophosphite ions formed or added separately therefrom will. 16. The method according to claim 15, characterized in that the double ammonia salt of an organic Acid is nickel ammonium glycolate. 17. The method according to claim 5, characterized in that the metal kypophosphite ions from nickel-ammonia-hypophosphite are formed. BAD ORiG «NAL 109820/1594 18. The method according to one or more of claims 1 to 17 »characterized in that, to produce a double imsonia-nickel complex connection, a basic nickel compound from the group containing nickel hydroxide and carbonate carbonate, a normal ammonia in an alkaline ammonia-containing medium at a pH A value of at least 8 in not more than the stoichiometric equivalent or the stoichiometric amount is added, whereby the normally insoluble Mckel base compound becomes completely soluble. r \ r \ η ri η J Λ r r \