EP1413646A2 - Process for electroless plating of metals - Google Patents

Abstract

In an electrolyte for electroless plating with nickel films with residual compressive stress, containing a nickel base salt (I), reducing agent, chelant, accelerator and stabilizer, (I) is Ni acetate in an initial concentration of 12-26 g/l. An Independent claim is also included for the process for electroless plating with this electrolyte, in which uniform Ni films are deposited at a constant high rate of deposition of not less than 7-12 microns/hour, with a throughput of not less than 15-22 MTO (metal turn-over) = 70-110 g Ni/l.

Description

This invention relates to an electrolyte for electroless deposition of residual stress metal layers containing a metal base salt, a reducing agent, a complexing agent, an accelerator and a stabilizer, preferably using nickel, copper, silver or gold, most preferably nickel, as the metal.

In addition to electrolytic processes for coating workpieces with a metal layer, so-called external current or electroless plating processes have long been known. Under electroless or even chemical metallization is a chemical surface refinement of almost all metals and many non-conductors to understand. It differs significantly in its chemical, physical and mechanical characteristics of galvanically applied metal coatings. It is advantageous, for example, that the chemical metallization takes place uniformly in the deepest boreholes and fits and, moreover, a virtually constant and contoured layer thickness is produced. These methods are particularly often used for coating non-conductive substrates, for example plastic parts, in order to make them conductive, for example by a metallic surface, and / or to give them an aesthetic appearance. Likewise, by such methods, the material properties of the substrates thus treated can be improved. Thus, depending on the method, for example, the corrosion resistance, hardness and / or wear resistance of the material used can be improved.

The electroless plating with metals is based on an autocatalytic process, so that it is also referred to as autocatalytic coating. In order to reduce the metal ions contained in the deposition bath (electrolyte) to elemental metal in such a coating process, the electrolyte must be added to a corresponding reducing agent, which is oxidized during the reaction itself. In addition, other components, such as phosphorus and / or additional metals, such as copper, etc., are often incorporated into the coating.

Thus, in the case of an electroless metal bath by the use of hypophosphite as a reducing agent metal coatings are produced with a relatively high phosphorus content. The corresponding reaction equation is as follows: $${\text{MSO}}_{\text{4}}{\text{+ CNaH}}_{\text{2}}{\text{PO}}_{\text{2}}{\text{→ M + 2H}}_{\text{2}}{\text{+ 2P + 4 NaH}}_{\text{2}}{\text{PO}}_{\text{3}}{\text{+ Na}}_{\text{2}}{\text{SO}}_{\text{4}}$$

Since the proportion of phosphorus has a significant influence on layer properties such as hardness and corrosion resistance, this is selectively introduced depending on the intended use of the coated article. For example, in the case of non-magnetic coatings with maximum hardness, a phosphorus content of ≥ 10% by weight is desired. In addition, such electroless deposited metal-phosphorus coatings have a higher hardness and better wear resistance than electrodeposited coatings.

However, hypophosphite baths for electroless deposition of metals tend to become unstable during deposition, as the concentration of metal and hypophosphite ion progressively decreases as the concentration of orthophosphite ion continues to increase and the counterions of the metal and hypophosphite ions increase Form of, for example, sodium sulfate. The electrolyte is thus consumed ".

The lifetime of such electroless baths is thus limited because the electrolyte can only be used for a certain number of coating runs with uniform coating results. The age of a bath will commonly reported in Metal Turn-Over (MTO), where 1 MTO is equal to the amount of metal deposited from the bath. This corresponds to the originally used concentration of the metal ions, in each case based on the total volume of the bath, in the bath. In the processes currently known in the art, the degradation products in the electrolyte reach such a high concentration after about 5 to 10 MTO that a high deposition rate and a consistently high quality of the deposited metal can no longer be guaranteed. The electrolyte is then either to replace or regenerate using appropriate tools.

However, the required disposal of the spent baths as well as the required new batch of fresh baths disadvantageously leads to high costs and a significant environmental impact.

The regeneration of an electrolyte for nickel deposition means at least withdrawing the resulting orthophosphite as reaction products and optionally an addition of metal and Hypophosphitionen. In previously known processes, interfering components are separated from the bath, for example by adsorption on ion exchange resins or by electrodialytic processes. Although such methods allow a significantly longer life of the baths, but they are usually connected by the complex structure, etc. with very high operating costs.

Another, less expensive form of regenerating baths for the electroless deposition of metals is the in situ precipitation and separation of unwanted ions in the form of sparingly soluble compounds and the subsequent replenishment of required and consumed in the course of bath life time. As precipitant but usually only rare metals in question, the acquisition in turn is very expensive. In addition, the dissolved in the bath dissolved components of these additives can affect the quality of the metal coating.

Furthermore, methods are already known in which interfering precipitations of metal orthophosphite are prevented by the addition of complexing agents, and thus, by the targeted reduction of the concentration of dissolved free Nickel ions, the stability of the baths can be significantly improved. Thus, in the past a wide variety of bath additives have been proposed, but all have the disadvantage that a uniform, non-porous and adherent deposition of metal-phosphorus coatings from such baths with an economically acceptable deposition rate of 7-10 microns / h and with compressive stresses at Phosphorus content of the coating of> 10% over a longer period is not possible. Usually, the life or the period of application of such baths is 7 to max. 10 MTO, using no S ^2- containing accelerators.

The invention has for its object to provide an electrolyte for the electroless deposition of metals from which over a longer period uniform, pore and crack-free metal-phosphorus coatings with constant layer properties and high phosphorus content, at an increased deposition rate, can be deposited. The metals used should preferably be nickel, copper, silver or gold, more preferably nickel. Furthermore, it is intended to provide an electrolyte with high stability and lifetime, containing complexing agents and stabilizers which are effective in a wide volume range and significantly contribute to increasing the rate of deposition and prolonging the life of the bath. Another object of the present invention is to provide a method for electroless deposition of metals, preferably nickel, copper, silver or gold, more preferably nickel.

The object is according to the invention by means of an electrolyte for the currentless deposition of metal layers, preferably nickel, copper, silver or gold, particularly preferably nickel with compressive residual stress, containing a metal base salt, a reducing agent, a complexing agent, an accelerator and a stabilizer achieved in that the electrolyte as Metal base salt, a metal salt whose anions are volatile and which has an initial concentration of 0.01 to 0.3 mol / l. This metal salt whose anions are volatile is preferably at least one salt selected from the group consisting of metal acetate, metal formate, metal nitrate, metal oxalate, metal propionate, metal citrate and metal ascorbate, preferably metal acetate.

By means of the electrolyte according to the invention, the disadvantages known in the state of the art are eliminated by providing a novel composition of the electrolyte and in this way achieving considerably better deposition conditions, thereby simplifying implementation and making it more economical. This is due in principle to the advantageous composition of the electrolyte. In particular, by the use of metal salts whose anions are volatile, preferably metal acetates as the electrolyte base salt, the life of the electrolyte at high deposition rates and uniformly deposited layers with constant layer properties can be significantly extended.

The electrolyte according to the invention is basically composed of one or more metal base salts, preferably metal acetate and a reducing agent, preferably sodium hypophosphite. Furthermore, various additives, such as complexing agents, accelerators and stabilizers, which are advantageously used in acidic electrolytes for the electroless deposition of nickel, are added to the electrolyte. Since the deposition rate is significantly higher in an acidic medium, an acid is preferably added to the electrolyte as a complexing agent. The use of carboxylic acids and / or polycarboxylic acids turns out to be particularly advantageous since, on the one hand, it determines the advantageous solubility of the metal salts and the controlled control of the free metal ions and, on the other hand, prescribes the adjustment of the pH required for the process due to their acid strength . facilitated. The pH of the electrolyte is advantageously in the range of 4.0 to 5.2. In addition, the dissolved metal is particularly advantageously complexed by the use of carboxylic acids and / or polycarboxylic acids whose salts and / or derivatives, preferably hydroxy (poly) carboxylic acids, particularly preferably 2-hydroxypropanoic acid and / or propanedioic acid. At the same time, these compounds serve as activators and as pH buffers and contribute significantly to the stability of the bath by their advantageous properties.

Advantageously, a sulfur-containing heterocycle is added to the electrolyte as accelerator. The sulfur-containing heterocycle used is preferably saccharin, its salts and / or derivatives, particularly preferably sodium saccharin. Unlike the ones in the prior art known and commonly used accelerators based on S ² , the addition of saccharinate does not adversely affect the corrosion resistance of the deposited metal layers even in higher concentration.

Another important prerequisite for rapid and high-quality deposition of metal layers is the use of suitable compounds for stabilizing the electrolyte. For this purpose, a number of different stabilizers are known in the art. However, since the stability of the electrolyte according to the invention is significantly influenced by the use of metal salts whose anions are volatile, preferably the acetates, formates, nitrates, oxalates, propionate, citrate and ascorbate of the metals, more preferably metal acetate, are advantageously only small amounts of Stabilizers used. This is on the one hand more economical, on the other hand precipitates etc. are avoided, which can be caused by the addition of additional substances and thus significantly shorten the life of the electrolyte. Thus, advantageously only small amounts of a stabilizer are added to the electrolyte according to the invention in order to counteract a spontaneous decomposition of the metallizing bath. These may be, for example, metals, halogen compounds and / or sulfur compounds, such as thioureas. In this case, the use of metals as stabilizers has proved to be particularly advantageous. Preference is given here to the use of lead, bismuth, zinc and / or tin, which are particularly preferably in the form of a salt whose anion contains at least one carbon atom. These salts are preferably one or more of the salts from the group consisting of acetates, formates, nitrates, oxalates, propionates, citrates and ascorbinates, more preferably acetates.

Depending on which additional properties the metal layers should have, besides phosphorus further components, such as, for example, additional metals, preferably cobalt, and / or finely dispersed particles are incorporated into the layer. In addition, the electrolyte according to the invention has smaller amounts of additional components, such as, for example, salts, preferably potassium iodide.

With respect to the above object, it is particularly preferred by a process for the electroless deposition of metal layers with compressive stresses, an electrolyte containing a metal base salt, a reducing agent, a complexing agent, an accelerator and a stabilizer, preferably nickel, copper, silver or gold as the metal Nickel is used, characterized in that from the electrolyte of the metal base salt as a metal salt, the anions are volatile and having a starting concentration of 0.01 to 0.3 mol / l, uniform metal layers at a consistently high deposition rate in the range of at least 7 to 12 .mu.m / h, with a throughput of at least 14 to 22 MTO = 70 to 110 g ni / l deposited. The metal salt whose anions are volatile is preferably at least one salt selected from the group consisting of the acetates, nitrates, formates, oxalates, propionates, citrates and ascorbate of the metals, more preferably metal acetate.

By using the method according to the invention, the quality of the metallizing bath is surprisingly improved and the service life is considerably prolonged. This has the advantage that not only high deposition rates are achieved by the use of the method according to the invention, but also that the nickel layers obtained by the process are uniform and of high quality, have a very good adhesion and are consistently free of pores and cracks. In addition, the metallization of the surface is improved, especially by more complex substrates. In particular, it is advantageous that uniform nickel layers with compressive residual stresses at a consistently high deposition rate in the range of at least 7 to 14 .mu.m / h, preferably 9 to 12 .mu.m / h with a throughput of at least 14 to 22 MTO = 70 to 110 g Ni / l are deposited ,

Surprisingly, a deposition of high-quality metal-phosphorus layers with phosphorus contents greater than 10% is possible under the same process conditions. This results in the advantageous use of the method according to the invention in a wide variety of areas. For example, the corrosion-resistant metal layers deposited according to the invention are suitable for coating keys or Locks, valves, pipelines, etc .. Due to the high phosphorus content, the layer is non-magnetic and is therefore ideal for coating plugs and contacts and housings for electronic devices, etc. Due to the very good wear resistance, the layers produced by the process according to the invention preferably used in the field of mechanical engineering for coating of running surfaces, couplings, pump housings, etc.

As already described above, the method proposed by the invention is characterized in particular by the composition of the electrolyte. It is therefore advantageously in an economical and environmentally friendly compared to the conventional methods. The electrolyte according to the invention can be regenerated, for example, by means of electrodialytic method. When using metal salts whose anions are volatile, the separation effect of the electrodialysis plant is significantly increased. With the same salt load of orthophosphite-containing but sulphation-free electrolytes, the number of electrolysis cells for separating Ortophosphitionen can be reduced at the same separation efficiency.

At the beginning of the process, the base electrolyte of the electrolyte according to the invention is applied. This contains z. B. in the case of a nickel plating essentially the following composition: 4 - 6 g / l nickel ions 25 - 60 g / l reducing agent 25 - 70 g / l complexing 1 - 25 g / l accelerator 0.1-2 mg / l stabilizer 0-3 g / l other ingredients

The pH range of such a base electrolyte is between 4.0 and 5.0. As already described above, metal salts whose anions are volatile are advantageously used as metal receivers. As metal salts whose anions are volatile one or more salts are preferably selected from the group consisting of metal acetates, metal formates, metal nitrates, metal oxalates, Metal propionates, metal citrates and Metallascorbinaten, particularly preferably used exclusively metal acetate. Since during the reaction, the pH falls through the continuous formation of H ⁺ ions and this must be kept consuming by alkaline media, such as hydroxide, carbonate, or as usually preferred by ammonia in target range, a particular advantage in the sole use of metal salts whose anions are volatile and which preferably originate from the group of the acetates, formates, nitrates, oxalates, propionates, citrates and ascorbinates. This is due to the fact that during the deposition of the metal-phosphorus layers anions of the acetates, formates, nitrate, oxalates, propionates, citrates and ascorbinates are formed, which react with the sodium carbon ions from the sodium hypophosphite to form basic sodium salts. The electrolyte according to the invention thus operates throughout the deposition process in a pH range of 4.0 to 5.2, preferably 4.3 to 4.8, without having to be additionally added larger amounts of alkaline media. Due to the extremely advantageous pH self-regulation can be dispensed with during the process on a continuous pH control and alkaline additives.

The starting concentration of the metal-base salts is 0.04 to 0.16 mol / l, preferably 0.048 to 0.105 mol / l, based on nickel, the content of metal being between 0.068 and 0.102 mol / l, preferably 0.085 mol / l.

The reducing agent used is preferably sodium hypophosphite having a starting concentration of 25 to 65 g / l.

As already explained above, the complexing agents used are carboxylic acids and / or polycarboxylic acids, their salts and / or derivatives, preferably hydroxy (poly) carboxylic acids, particularly preferably 2-hydroxypropanoic acid and / or propanedioic acid. By using these compounds, the dissolved nickel is particularly advantageously complexed, so that the deposition rate can be maintained in a corresponding interval of 7 to 14 .mu.m / h, preferably 9 to 12 .mu.m / h with continuous addition of such complexing agents. The starting concentration of the complexing agent in the base electrolyte is between 25 and 70 g / l, preferably 30 to 65 g / l.

The starting concentration of the accelerator, preferably using a sulfur-containing heterocycle, more preferably saccharin, its salts and / or derivatives, most preferably sodium saccharin, is from 1 to 25 g / l, preferably from 2.5 to 22 g / l. As stabilizers halogen compound and / or sulfur compound, preferably thiourea can be used. Particularly advantageous, however, is the use of metals, preferably lead, bismuth, zinc and / or tin, particularly preferably in the form of salts whose anions are volatile. These salts are preferably selected from the group consisting of acetates, formates, nitrates, oxalates, propionates, citrates and ascorbinates. Very particular preference is given to the nitrates of the metals used as stabilizers. The starting concentrations of the stabilizers are advantageously from 0.1 to 2 mg / l, preferably from 0.3 to 1 mg / l.

Optionally, further constituents, for example potassium iodide, in a starting concentration of 0 to 3 g / l may also be added to the base electrolyte.

In this basic electrolyte a variety of substrates are introduced and galvanized. To support the lifetime and the stability of the electrolyte, it can be regenerated during the deposition process by means of electrodialysis and / or ion exchange resins. Likewise, supplemental solutions (as exemplified below) may be added to the electrolyte during the deposition process. These replenisher solutions are specially designed to control the individual contents of the basic components and added to the electrolyte in different amounts.

A first replenisher solution includes, for example, the following composition: 500 - 580 g / l reducing agent 5 - 15 g / l complexing 50-150 g / l alkaline buffer 11-20 g / l accelerator 0-3 g / l other ingredients

When creating and using the replenisher solution, the same substances as in the base electrolyte are advantageously used. This results in another very important advantage of the method according to the invention. Since the same substances are used continuously and there are almost no impurities and precipitations, even the compounds from the sink can be returned to the electrolyte. The inventive method thus has a decided material cycle, which can be the process thus more economical and environmentally conscious. The complexing agent content and the content of alkaline buffer are chosen so that, taking into account possible carry-over losses of not more than 40%, an increase to a total content of the complexing agents in the electrolyte to 70 to 90 g / l.

At the same time the content of the accelerator in the electrolyte is controlled so that, for example, in the case of a nickel electrolyte with the use of sodium saccharinate as accelerator per gram of deposited nickel between 0.100 and 0.200 g, preferably 0.150 g are added, wherein the proportion of carryover losses is taken into account. This ensures at the same time a continuous increase to 7.5 - 15 g / l.

As a second replenisher, for example, the following composition can be used: 10 - 50 g / l complexing 0.68 - 2.283 mol / l Metallrezipient 1 - 25 g / l accelerator 40-80 mg / l stabilizer

In this case, the complexing agent of the second replenisher solution may be the same as in the first replenisher or, if necessary, another. Thus, for example, in the case of a content of a hydroxycarboxylic acid, for example 2-hydroxypropanoic acid of 60 g / l, a hydroxycarboxylic acid, for example propanedioic acid with a content of 0.5 g / l, can be used as second complexing agent in the base electrolyte. By adding by means of replenisher, the content of propanedioic acid is then increased by 0.005 to 0.015 g / g of precipitated nickel, with the carry-over losses with are considered. Due to the continuous increase of propanedioic acid from 0.5 g / l to about 1.2 g / l at 16 MTO equal to 80 g Ni / l, the deposition rate is maintained at the specified interval.

With such an approach as well as the associated replenisher solution, the use of metal sulfate in addition to the metal base salts described so far ensures a separation of adherent metal layers with residual compressive stresses up to a throughput of at least 14 MTO. If only metal-base salts are used whose anion has at least one carbon atom and which preferably originate from the group of acetates, formates, oxalates, propionates, citrates and ascorbinates, the lifetime of the electrolyte surprisingly increases to up to 22 MTO. The already mentioned compressive residual stress is an extremely important and very desirable layer property. It positively influences the bending cycle stress and increases the ductility. So z. For example, in the case of nickel, metal layers with a ductility of> 0.5% are deposited. Likewise, the residual compressive stresses have a positive effect on the corrosion resistance of the metal-phosphorus layers.

In addition, other components such as additional metals, preferably copper, and / or finely disperse particles, such as finely dispersed fluorine-containing thermoset or thermosetting plastic, may be added to the electrolyte as well as the replenisher, which in the deposited layers additional hardness, dry lubricating effects and / or achieve other properties.

For a more detailed illustration of the invention, a preferred embodiment of the electrolyte according to the invention is described below, to which, however, the invention can not be limited.

Example 1:

composition electrolyte Supplementary solution RA Supplementary solution SA Nickel acetate 4-hydrate (g / l) 12.5 - 25.5 / 200 - 212 Sodium hypophosphite (g / l) 30 - 50 515-565 / Hydroxycarboxylic acid (g / l) 32 - 55 / 25 - 35 Hydroxypolycarboxylic acid (g / l) 0,5 - 5 / / Sodium saccharin (g / l) 2.5 - 22 12.5 - 15 / Potassium iodide (g / l) 0.1 - 2 1 - 2 / Lead acetate (mg / l) 0.3 - 1 / 60 - 65 Ammonia 25% by weight (ml / l) 100-150

Such an electrolyte has a self-regulating pH range of 4.3 to 4.8 and allows deposition rates of 8 to 12 μm / hr. The internal stress of the layers deposited therefrom is -10 to -40 N / mm ² . When using the above electrolyte composition metal phosphorus layers with consistently good properties, especially residual compressive stresses at a throughput of 22 MTO equal to 110 g Nill deposited.

By raising the pH range to 4.6 - 5.2 layers with residual compressive stresses of 0 to - 15 N / mm ^{2 are} deposited. The determination of a second pH interval leads to a significant increase in the deposition rate to 12-20 μm / h. The phosphorus content of these layers is 8-10% P. By further raising the pH range to 5.5-6.2, layers with residual compressive stresses of -5 to -30 N / mm ^{2 are} deposited. The phosphorus content of these layers is 2-7% P.

Claims (32)

Electrolyte for the electroless deposition of pressure-level nickel layers containing a metal-base salt, a reducing agent, a complexing agent, an accelerator and a stabilizer,
characterized,
in that the electrolyte has, as metal base salt, a metal salt whose anions are volatile and which is present in a starting concentration of 0.01 to 0.30 mol / l. An electrolyte according to claim 1, characterized in that it comprises as the metal salt, the anions are volatile, at least one salt selected from the group consisting of metal acetate, metal formate, metal oxalate, metal nitrates, metal propionate, metal citrate and Metallascorbinat. Electrolyte according to one or more of claims 1 and 2, characterized in that it comprises a metal sulfate as a further metal base salt. Electrolyte according to one or more of claims 1 to 3, characterized in that it comprises sodium hypophosphite as reducing agent. Electrolyte according to one or more of Claims 1 to 4, characterized in that the metal used is preferably nickel, copper, silver or gold, more preferably nickel. Electrolyte according to one or more of claims 1 to 5, characterized in that it comprises as further components metals, preferably copper, and / or finely dispersed particles. Electrolyte according to one or more of Claims 1 to 6, characterized in that it contains as complexing agents carboxylic acids and / or polycarboxylic acids, their salts and / or derivatives, preferably Hydroxy (poly) carboxylic acids, particularly preferably 2-hydroxy-propanoic acid and / or propanedioic acid. Electrolyte according to one or more of claims 1 to 7, characterized in that this complexing agent is present with a total content of at most 70 g / l - 90 g / l. Electrolyte according to one or more of claims 1 to 8, characterized in that it comprises as accelerator a sulfur-containing heterocycle. An electrolyte according to claim 9, characterized in that it comprises as sulfur-containing heterocycle saccharin, its salts and / or derivatives, preferably sodium saccharinate. Electrolyte according to one or more of Claims 1 to 10, characterized in that it has halogen compounds, sulfur compounds and / or metals as stabilizers. Electrolyte according to one or more of Claims 1 to 11, characterized in that it comprises as stabilizers metals, preferably lead, bismuth, zinc and / or tin, more preferably in the form of a salt whose anions are volatile. An electrolyte according to claim 12, characterized in that it comprises as anions of the stabilizers at least one anion from the group consisting of acetates, formates, nitrates, oxalates, propionates, citrates and ascorbinates. Electrolyte according to one or more of claims 1 to 13, characterized in that it comprises additional components, such as salts, preferably potassium iodide. Electrolyte according to one or more of claims 1 to 14, characterized by 0.01-0.3 mol / l metal acetate, 30 to 50 g / l Sodium mono-hydrate, 90 to 120 g / l Hydroxycarboxylic acid alkaline buffered, 0.5 to 10 g / l hydroxypolycarboxylic, 2.5 to 22 g / l saccharinate, 0.1 to 2 g / l Potassium iodide and 0.3 to 1.5 mg / l Lead acetate. Process for the electroless deposition of nickel layers with residual compressive stresses, consisting of an electrolyte containing a metal base salt, a reducing agent, a complexing agent, an accelerator and a stabilizer,
characterized,
in that, from the electrolyte containing, as metal base salt, a metal salt whose anions are volatile and which has a starting concentration of 0.048 to 0.105 mol / l, uniform metal layers at a consistently high deposition rate in the range of at least 7 to 12 μm / h, with a throughput of at least 14 to 22 MTO = 70 to 110 g metal / l are deposited. Process according to Claim 16, characterized in that, as the metal salt whose anions are volatile, at least one salt from the group consisting of the acetates, formates, oxalates, propionates, citrates or ascorbinates of the metal is used. Process according to one or more of Claims 16 and 17, characterized in that the metal used is preferably nickel, copper, silver or gold, more preferably nickel. Process according to one or more of Claims 16 to 18, characterized in that a replenisher solution is added to the electrolyte during the course of the process. Method according to one or more of claims 16 to 19, characterized in that the electrolyte in the course of Implementation added added a reducing agent, an alkaline buffered complexing agent and an accelerator. Process according to one or more of Claims 16 to 20, characterized in that a second replenisher solution is added to the electrolyte during the course of the process. Process according to one or more of Claims 16 to 21, characterized in that the second replenisher solution added to the electrolyte in the course of carrying out the process comprises a nickel-base salt, a complexing agent, accelerator and a stabilizer. Method according to one or more of claims 16 to 22, characterized. that the process is carried out with a closed material cycle. Method according to one or more of claims 16 to 23, characterized in that in addition further components, such as phosphorus and / or additional metals, preferably cobalt, and / or finely dispersed particles are also deposited. Process according to one or more of claims 16 to 24, characterized in that metal-phosphorus layers with phosphorus contents> 10% are deposited. Process according to one or more of Claims 16 to 25, characterized in that metal phosphor layers with phosphorus contents of 2-10% are deposited, the pH being preferably 4.6-6.2. Process according to one or more of Claims 16 to 26, characterized in that sodium hypophosphite is preferably used as the reducing agent. Process according to one or more of Claims 16 to 27, characterized in that the complexing agents used are carboxylic acids and / or polycarboxylic acids, their salts and / or derivatives, preferably hydroxy (poly) carboxylic acids, particularly preferably 2-hydroxypropanoic acid and / or propanedioic acid , Process according to one or more of Claims 16 to 28, characterized in that the total content of the complexing agents in the course of the precipitation process is 70 g / l - 90 g / l. Process according to one or more of Claims 16 to 29, characterized in that the accelerator used is a sulfur-containing heterocycle. Process according to Claim 30, characterized in that the sulfur-containing heterocycle used is saccharin, its salts and / or derivatives, preferably sodium saccharinate. Process according to one or more of Claims 16 to 31, characterized in that the electrolyte is regenerated by means of electrodialysis and / or ion exchange resins.