Patent Application
20250034718
The present invention according to a first aspect and second aspect relates to a use of an aqueous alkaline deposition composition for the electroless deposition of a metal or metal alloy, in particular silver, nickel, manganese, cobalt, or copper, on a metal surface of a substrate.
According to a third aspect the present invention is further directed to a method for the electroless deposition of a metal or metal alloy, in particular silver, nickel, manganese, cobalt, or copper, on a metal surface of a metal substrate, with an aqueous alkaline deposition composition according to the first aspect.
According to a fourth aspect the present invention is further directed to a method for the electroless deposition of a metal or metal alloy, in particular silver, nickel, manganese, cobalt, or copper, on a metal surface of a substrate, with an aqueous alkaline deposition composition according to the second aspect.
According to a fifth aspect the present invention is further directed to a substrate with a deposited metal or metal alloy layer, in particular a silver, nickel, manganese, cobalt, or copper layer, on the metal surface of the substrate, wherein the deposited metal or metal alloy layer has been obtained by a method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate according to the third or fourth aspect.
Substrates, such as metal-base substrates, can be coated by various metals or metal alloys to provide a metal coating layer on the surface of the respective substrate. Depending on the type of metal or metal alloy and the material of the surface of the substrate, various applications are possible.
For example, U.S. Pat. No. 3,472,742 refers to plating nickel on aluminum castings. Disclosed is a process comprising a step of treating aluminum with a relatively hot electroless nickel plating solution to apply a flash plate of nickel thereto.
U.S. Pat. No. 3,666,529 refers to a method of conditioning aluminous surfaces for the reception of electroless nickel plating.
EP 3 360 988 A1 refers to a pyridinium compound comprising a building block -[A-D)- having a part (A) a urea or biuret structure which has at least at one pyridinium residue and a nitrogen-containing residue X1 and X2 and wherein the urea or biuret structure is bounded to a part (D) an ether or thioether group. The pyridinium compound is suitable as plating additive for copper deposition.
First, said metal coatings can serve as functional layers on the surface of the respective substrate to allow for an effective protection of the substrate, e.g. against aggressive gases or liquids by means of corrosion resistant metal coatings, the type of which is determined essentially by the intended use of the article.
Second, said metal coatings can serve as decorative layers on the surface of the respective substrate to allow for the desired optical surface characteristic.
Third, said metal coatings can provide electrically conductive structures on the surface of the respective substrate to allow for example for the preparation of electric circuit boards.
Exemplified metal coatings according to the present application comprise silver, nickel, manganese, copper, or cobalt coatings, which can be applied to a variety of substrates, for example metal substrates.
To apply said metal or metal alloy coatings to the respective substrates, the corresponding metals have to be stabilized in the respective deposition composition to avoid aggregation of metal deposits in said deposition compositions.
It was therefore the first objective of the present invention to provide a use of a deposition composition and method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, which allow for an efficient metal deposition, in particular in a metal deposition resulting in a homogenous and closed metal coating layer on the metal surface of a substrate. This preferably includes to provide a simplified method such that for example less pre-treatment steps or even no common pre-treatment steps are necessary anymore, generally resulting is a method sequence with a reduced number of steps.
It was therefore the second objective of the present invention to provide a use of a deposition composition and method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, which can be applied using a wide variety of metals or metal alloys, for example silver, nickel, manganese, cobalt, or copper.
It was therefore the third objective of the present invention to provide a use of a deposition composition and method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, which can be employed for the electroless deposition on a plurality of different metal surfaces, for example copper, brass, aluminum, zinc, and/or steel surfaces as well as zinc-coated steel.
It was therefore the fourth objective of the present invention to provide a use of a deposition composition and method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, which can be used for the electroless deposition on a plurality of different metal substrates, for example large-area metal surfaces in the technical field of general manufacturing on the one side and also fine structures on printed circuit boards in the technical field of electronics on the other side.
It was therefore the fifth objective of the present invention to provide a use of a deposition composition and method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, wherein the deposition composition can be regenerated to allow for an environmentally friendly and cost-effective process. This most preferably includes that a respective deposition composition provides a longer life-time and utilization-time within a respective method.
It was therefore the sixth objective of the present invention to provide a use of a deposition composition and method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, which the metal ions are effectively stabilized in the deposition composition to prevent precipitation.
It was therefore the seventh objective of the present invention to provide a use of a deposition composition and method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, wherein additional layers, which are subsequently deposited on the deposited metal coating have superior functional and/or decorative qualities.
It was therefore the eighth objective of the present invention to provide a use of a deposition composition and method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, which contains chemical compounds with a reduced toxicity.
Finally, it was an objective to provide a use of an improved electroless deposition composition and method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, such that use of an electrical current for deposition can be avoided.
The aforementioned objectives are solved according to the present invention and in particular according to the first aspect to fifth aspect.
According to the first aspect by a use of an aqueous alkaline deposition composition for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, the composition comprising:
Preferably, the aqueous alkaline deposition composition comprises a pH from 7.1 to 13.
The used aqueous alkaline deposition composition for the electroless deposition of a metal or metal alloy on a metal surface of a substrate allows for an efficient deposition of a wide variety of metals or metal alloys on a wide variety of substrate metal surfaces (see examples below). “Metal surface of a substrate” in the context of the present invention comprises a substrate made of metal or metal layers having a metal surface (wherein the metal or metal layer provides the metal surface to be treated). The substrate also comprises any other (non-metallic) material as resin, glass, composites thereof comprising a metal surface to be treated onto the non-metallic substrate. Both substrates will be used therein interchangeable, if not mentioned otherwise.
If “functionalized urea derivatives” is mentioned in the following it always includes the meaning of “and/or salts thereof”, except it is stated otherwise.
It was surprisingly found that the functionalized urea derivative as defined under (a) provides outstanding capabilities in dissolving, complexing, and depositing this wide variety of metals or metal alloys on said wide variety of substrate metal surfaces. Most interestingly, these compounds fulfill this role at the same time. It has been found that compounds of (a) can be utilized in a very flexible and therefore reversible manner. For example, in many cases, such as for Zn, Al, Sn, and Mn metal surfaces, compounds of (a) slightly dissolve the very metal surface of such substrates. This results on the one hand on a freshly prepared metal surface of the substrate for subsequent metallization and therefore means that typical pre-treatment steps can be omitted.
Further, it has been observed that such dissolved metals form precipitates in the deposition composition that can be simply removed by filtration. This means that compounds of (a) have the dissolving ability without complexing these metals too strong. This in turn means that at the same time, compounds of (a) can be loaded either directly with metal ions to be deposited by a metal salt, dissolve a solid metal piece of the metal by oxidation or metal anode material by applying electrical current to provide a respective source of ions to be deposited for metal deposition. Furthermore, such loaded ions are surprisingly directly deposited onto the metal surface of the substrate or freshly prepared metal surface of the substrate. Also surprisingly, the deposition onto the metal surface does neither require an electrical current nor a reducing agent for reducing said metal ions. This means that pure metal layers can be deposited onto the metal surface. In this context “pure” means that no alloying elements as boron or nitrogen were co-deposited which normally occurs by using boron or nitrogen containing reducing agents. “pure” in this context means a metal content of the deposited metal layer of at least 98 wt.-%, more preferred 99 wt.-% and most preferred 99.9 wt.-%.
As a consequence of the aforementioned, the aqueous alkaline deposition composition is used according to the invention for the electroless deposition of a metal or metal alloy, wherein the electroless deposition is a so-called immersion deposition wherein the aqueous alkaline deposition composition does not comprise any intentionally added reducing agent (further details see in the text below).
In the composition, the functionalized urea derivatives are forming a complex with the metal ions to be deposited. When the composition is used, e.g. brought into contact with the metal or the metal surface of the metal substrate, the redox potential of the formed complex is more noble than metal or metal surface of a metal substrate. For example, it could be found that normally less noble manganese (redox potential of −1.03 V against hydrogen) could be shifted by complexing with the inventive functionalized urea derivatives to a more noble potential. In consequence, manganese could be deposited on the normally more zinc surface (redox potential of −0.77 V against hydrogen).
Since the compound (a) is again available after depositing the loaded metal ion (derived from the source of metal ions), it can participate again in this cycle. Despite unavoidable drag out and partly film deposition onto the deposited metal of a very small amount of the compound (a), the total amount of compound (a) remains relatively stable. Due to the absence of an electrical current, no electrolytic decomposition or breakdown is observed.
As mentioned, the aforementioned cycle most preferably applies to Zn, Al, Sn, and Mn substrates and basically can be carried out for a very long time. Further explanations and preferred features are given throughout the text. However, if the substrate is a Cu substrate, compound (a) still dissolves the very metal surface of the substrate, but copper is more significantly complexed by compound (a) as in case of Zn, Al, Sn, and Mn substrates. As a result thereof, compound (a) starts to become saturated with copper ions after a while. Although the principle of the present invention is still applicable, compound (a) must be released from copper ions at least after a while. Thus, the cycle is comparatively shorter compared to Zn, Al, Sn, and Mn substrates. However, own experiments have shown that such a release can be obtained by simply applying a temperature increase for a comparatively short time to also form a respective copper precipitate, which can be filtered in a subsequent step (see examples below).
In particular, the use of the aqueous alkaline deposition composition allows for an efficient deposition of silver, nickel, manganese, cobalt, or copper. From the definition of “at least one source of metal ions” above, it becomes clear, that e.g. copper cannot be deposited if copper is also the metal of the metal surface to be treated.
Moreover, the aqueous alkaline deposition composition allows for a homogenous deposition of the metal or metal alloy on the metal surface of the substrate during the deposition process, which in turn minimizes surface defects of the resulting metal coating. Such an efficient deposition process is in particular characterized by a constant deposition rate, which allows for an evenly distributed deposition of metal or metal alloy on the substrate surface during the deposition process, which in turn results in an even and closed metal surface, which can be obtained after the deposition process. “closed” in this context means that the obtained metal surface does not show depositing errors as holes.
Moreover, without to be bound by theory, the aqueous alkaline deposition composition seems to provide an effective roughness of the metal surface to be treated onto which the metal or metal alloy layer is deposited. This in turn improves the adhesion of the deposited layer and also of any additional layers, which are subsequently deposited on the deposited metal coatings. Such effective roughness of the treated metal surface can obviously be transmitted to the additionally deposited layer, which consequently also comprise a increased roughness, resulting in optimal functional and/or decorative properties of the resulting surfaces.
Further, the deposited metal surface shows good anti-tarnishing characteristics. It could be found by own experiment, that the obtained metal surface, in particular in case of silver deposition, did not tarnish over time and also fingerprints did not remain on the surface or could be wiped away easily. Without to be bound by theory, it seems that the used compound (a) in the aqueous alkaline deposition composition remains at the resulting surface as a film and mitigates the improved anti-tarnishing effect. Own experiments show anti-tarnishing protection e.g. of a deposited silver surface of several months up to one year. The deposited thin film of compound (a) also shows a positive effect on corrosion resistance.
Furthermore, the aqueous alkaline deposition composition can be applied for the electroless deposition on a variety of different substrates, in particular metal substrates with a metal surface, as foils, sheets, screws, bolts and the like or a substrate comprising a metal surface, such as larger metal surface areas onto plastic parts in the technical field of general metal finishing; or smaller metal surface areas as panels, foils, printed circuit boards (PCBs) or metallic structures e.g. conductive lines and vias, in the technical field of electronics. The substrates which can be used with the present invention are e.g. substrates selected from the group consisting of copper-coated laminate or resin; copper-plated FR4- or HMP-panels; PCBs or ABS resin having a copper surface; glass panels or silicon wafer having at least one copper surface to be treated; sheets or foils made of copper, brass, zinc-coated steel parts; copper or copper-plated panels; connector or socket substrates as aluminum or copper sockets/connectors; and hinges and rims made of aluminum.
Moreover, the functionalized urea derivatives and/or salts thereof selected from the group comprising compounds having formula I of the aqueous alkaline deposition composition allow for an efficient stabilization of the metal ions present in the deposition composition, in particular by chelating (complexing), so that the precipitation tendency of said metal ions can be minimized.
In particular the aqueous alkaline deposition composition does not need the addition of further stabilizing agents, preferably the aqueous alkaline deposition composition does explicitly not contain stabilizing agents for stabilizing the metal ions in the deposition composition, because the functionalized urea derivatives according to the present invention are able to form chelates of the obtained metal ions and thereby stabilizing the metal ions.
Moreover, the compounds of formula I are less toxic compared to other deposition compounds previously used in the prior art.
An additional particular advantage of the aqueous alkaline deposition composition according to the invention is the possibility to regenerate the compounds of said composition to allow for an environmentally friendly and cost-effective process.
The first to eighth objectives mentioned above are solved according to the invention. A use is preferred wherein the aqueous alkaline deposition composition uses preferably at least one source of metal ions which is selected from a group consisting of
The alternative (iii) is preferably provided in a separate tank to directly provide a solution of a complex of (a), (b) and optionally (c) wherein the oxidizing agent is preferably completely consumed. This solution is than added to the aqueous alkaline deposition composition to be used. This avoids the presence of oxidizing agent in the aqueous alkaline deposition composition. The oxidizing agent, preferably oxygen only, which is solved within the deposition composition, added to the deposition composition (e.g. by mixing and agitation of the deposition composition) thereby only allows for an effective oxidization of the solid metal piece in the deposition composition, thereby providing metal ions to be plated in the deposition composition. More preferred solved oxygen is the only oxidizing agent, wherein no other oxidizing agent is added.
Preferably the at least one source of metal ions is (i) at least one metal salt and/or (ii) a metal anode material which is in contact with the aqueous alkaline deposition composition, wherein said metal anode material is oxidized by applying an electric current to said anode, to enable an anodic oxidation process, resulting in a release of metal ions into the aqueous alkaline deposition composition. More preferred the at least one source of metal ions is (i) at least one metal salt.
In particular, the at least one source of metal ions of the aqueous alkaline deposition composition according to the invention can be directly applied to the deposition composition in ionic form, for example by directly dissolving a metal salt in the deposition composition, so that no oxidation of any elemental metal is necessary.
Alternatively or in addition, in particular, the at least one source of metal ions of the aqueous alkaline deposition composition according to the invention can be derived from a metal anode material, which is in contact with the aqueous alkaline deposition composition, wherein said metal anode material is oxidized by applying an electric current to said anode, to enable an anodic oxidation process, resulting in a release of metal ions into the aqueous alkaline deposition composition, so that in this case also no oxidation of any elemental metal is necessary.
In case that the at least one source of metal ions is selected from a group consisting of (i) and (ii), the composition does not comprise any additionally added oxidation agents.
The objectives mentioned above are solved according to a third aspect by a method for the electroless deposition of a metal or metal alloy on a metal surface of a metal substrate (wherein the metal substrate provides said metal surface to be treated), the method comprising the steps:
The objectives mentioned above are solved according to a fourth aspect by a method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, the method comprising the steps:
Said methods for electroless deposition according to the third and fourth aspect allow for a superior metal deposition on the substrate to be treated.
The objectives mentioned above are solved according to a fifth aspect by a substrate with a deposited metal or metal alloy layer on the metal surface of the substrate, wherein the deposited metal or metal alloy layer has been obtained by a method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate according to the third or fourth aspect. Said substrate, in particular metal substrate, comprises an effective metal deposit.
Surprisingly, it could be observed, that during and after the deposition of the metal derived from the metal ions to be deposited, the functionalized urea derivatives are partly coated as a thin film onto the deposited metal surface. This film functions on the one hand as corrosion protection layer and anti-tarnishing layer e.g. for silver deposits. On the other hand, the coated functionalized urea derivatives lose its complexing activity and the re-resolution of the deposited metal.
In the context of the present invention, the term “at least one” or “one or more” denotes (and is exchangeable with) “one, two, three or more than three”.
The term Cx-Cy according to the present invention refers to a substance comprising a total number from X carbon atoms to Y carbon atoms. For example, the term C1-C6 alkyl refers to alkyl compounds comprising a total number from 1 carbon atom to 6 carbon atoms.
The present invention according to the first aspect provides a use of an aqueous alkaline deposition composition for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, the composition comprising:
It is clear to the skilled person that at least one source of alloying metal ions is needed if a metal alloy shall be deposited on the metal surface of a substrate, instead of a single metal. Those alloying metals are preferred which have similar electrochemical potentials if complexed by compound (a) of the present invention and which are different to the metal of the metal surface to be treated.
According to the first and/or second aspect R1 and R2 are independently selected as nitrogen-comprising heteroaromatic compounds, wherein said nitrogen-comprising heteroaromatic compounds are preferably 4- to 10-membered heteroaromatic compounds comprising from 1 to 4 nitrogen atoms.
One advantage, which is achieved by the use of the aqueous alkaline deposition composition according to the first and/or second aspect of the present invention, results in an efficient deposition, for a variety of metals and/or metal alloys, in particular silver, nickel, manganese, cobalt, or copper, in particular resulting in a homogenous metal deposit. If one of these metals is used as the source of metal ions, two or more of the remaining sources can be used as alloying metal ions.
By using said aqueous alkaline deposition composition according to the first and/or second aspect of the present invention an effective roughness of the obtained metal deposits can be achieved, which allows for an efficient adhesion of any additional layer deposited on the metal deposit.
In particular, the used aqueous alkaline deposition composition can be regenerated so that the material consumption is limited, and a cost-effective and environmentally friendly process can be ensured.
Moreover, due to the nitrogen functionalities present in the functionalized urea derivatives having formula I, a highly efficient stabilization of metal ions in the composition can be achieved by chelating of said metal ions, which results in a reduced precipitation tendency of said metal ions.
In the following, advantageous embodiments of the deposition composition to be used according to the present invention will be explained in more detail.
According to the inventive use, the deposition composition is an aqueous alkaline deposition composition, which preferably comprises more than 50 vol.-% water, based on the total volume of the aqueous alkaline deposition composition, more preferably comprises 75 vol.-% or more water, even more preferably comprises 85 vol.-% or more water, even more preferably comprises 90 vol.-% or more water, even more preferably comprises 95 vol.-% or more water, and most preferably comprises 99 vol.-% or more water. Preferably, water is the only solvent in the aqueous alkaline deposition composition.
Preferably, the oxidizing agent for oxidizing the at least one metal for the deposition composition, which is present preferably in a solution in a separate tank to provide metal ions to be deposited, comprises oxygen dissolved in said solution.
Preferably the oxygen dissolved in the solution originates from atmospheric oxygen diffusing from the ambient air into the solution.
An aqueous alkaline deposition composition is preferred, wherein at least one of R1 and R2 is selected as substituted and/or unsubstituted 4- to 10-membered heteroaromatic compounds, optionally comprising from 1 to 4 nitrogen atoms, optionally comprising at least one substituent selected from the group comprising OR6 and C1-C4 alkyl, wherein R6 is selected from the group comprising hydrogen and C1-C3 alkyl;
An aqueous alkaline deposition composition is preferred, wherein both of R1 and R2 is selected as substituted and/or unsubstituted 4- to 10-membered heteroaromatic compounds, optionally comprising from 1 to 4 nitrogen atoms, optionally comprising at least one substituent selected from the group comprising OR6 and C1-C4 alkyl, wherein R6 is selected from the group comprising hydrogen and C1-C3 alkyl;
An aqueous alkaline deposition composition is preferred, wherein n is an integer from 2 to 3.
An aqueous alkaline deposition composition is preferred, wherein m is an integer from 2 to 3.
An aqueous alkaline deposition composition is preferred, wherein the functionalized urea derivatives and/or salts thereof are selected as compounds having formula I and/or salts thereof, wherein m is 3, wherein n is 3,
An aqueous alkaline deposition composition is preferred, wherein for the compounds having formula I and/or salts thereof, X is selected as oxygen, m and n are both selected as 3, and R1 and R2 are both selected as imidazole, preferably unsubstituted imidazole.
An aqueous alkaline deposition composition is preferred, wherein the compounds having formula I and/or salts thereof are present in the composition preferably at a total concentration from 2 wt.-% to 15 wt.-%, more preferably from 5 wt.-% to 15 wt.-%, even more preferably from 7 wt.-% to 15 wt.-%, and most preferably from 10 wt.-% to 15 wt.-%.
By selecting the concentration of the compounds having formula I of compound (a) in the preferred concentration ranges an efficient deposition process can be ensured.
An aqueous alkaline deposition composition is preferred, wherein the composition does not comprise any additional oxidizing agent, wherein preferably the composition does not comprise any peroxide and/or persulfate compound. A use of an aqueous alkaline deposition composition according to the second aspect of the present invention is preferred, wherein the at least source of metal ions comprises at least one metal salt, for example copper chloride. Therefore, due to the addition of the metal salt no oxidation of any elemental metal in the deposition composition is necessary.
A use of an aqueous alkaline deposition composition according to the second aspect of the present invention is preferred, wherein the at least one source of metal ions is derived from a metal anode material, which is in contact with the aqueous alkaline deposition composition, wherein said metal anode material is oxidized by applying an electric current to said anode, to enable an anodic oxidation process. Therefore, due to the anodic oxidation no addition of any metal salt or oxidizing agent to the deposition composition is necessary. Preferably the deposition composition comprises an anionic agent as carboxylic acids and/or alkyl sulfonic acids and their salts.
In a preferred embodiment of the invention, the source of metal ions is a nickel anode which is dissolved within the deposition composition by applying an electrical current to obtain nickel ions. Preferable in this embodiment the deposition composition comprises citric acid. The current can be applied continuously or semi-continuously. The aqueous deposition composition is an aqueous alkaline deposition composition. In the context of the present invention, the term “alkaline” denotes alkaline, i.e. having a pH above 7. The pH is preferably ranging from 7.1 to 13. An aqueous alkaline deposition composition of the present invention is preferred, wherein the aqueous alkaline deposition composition comprises a pH from 8 to 13, preferably from 9 to 12, more preferably from 9 to 11, and most preferably from 9.5 to 10.5.
By selecting the pH in the preferred ranges an efficient deposition process can be ensured.
An aqueous alkaline deposition composition is preferred, wherein the at least one metal, which is to be deposited onto the metal surface, is selected from the group consisting of manganese, silver, copper, cobalt, or nickel. In case, the at least one metal is selected from the group consisting of manganese, copper, cobalt, or nickel, the metal of the metal surface to be treated cannot be manganese, copper, cobalt, or nickel at the same time, because the metal of the metal surface must be less noble than the metal to be deposited.
An aqueous alkaline deposition composition according to the second aspect is preferred, wherein the at least one metal source comprises manganese, silver, copper, cobalt, or nickel, in particular in ionic form, if the at least one metal source comprises a metal salt or if the at least one metal source is released into the deposition composition by anodic oxidation.
An aqueous alkaline deposition composition is preferred, wherein the at least one metal is present in the composition at a total concentration from 0.1 wt.-% to 15 wt.-% based on the total weight of the composition, preferably at a total concentration from 1 wt.-% to 12 wt.-%, more preferably from 0.75 wt.-% to 5 wt.-%, even more preferably from 1 wt.-% to 3 wt.-%, and most preferably from 1 wt.-% to 2 wt.-%.
In respect to the use of the aqueous alkaline deposition composition according to the second aspect, the above concentrations within the deposition composition also apply to the at least one metal derived from the at least one metal source either by adding the salt into the deposition composition or by releasing the corresponding metal ions into the deposition composition by anodic oxidation.
A use of an aqueous alkaline deposition composition of the present invention is preferred, wherein the substrate is a metal substrate wherein the metal provides the metal surface to be treated or substrate comprising a metal surface, which more preferably comprises metals or metal alloys selected from the group comprising copper, nickel, aluminum, cobalt, manganese, zinc, lead, antimony, tin, rare earth metals, for example neodymium, copper-zinc alloy, copper-tin alloy, copper-nickel alloy, and aluminum-magnesium alloy.
A use of an aqueous alkaline deposition composition of the present invention is preferred, wherein the substrate comprises copper, nickel, aluminum, zinc, or zinc coated steel.
An aqueous alkaline deposition composition is preferred, wherein the composition does not comprise an anionic agent. It could be found by own experiments that the addition of an acid, as hydrochloric acid, sulfuric acid, bromic acid, carboxylic acids as mono-, di- or tricarboxylic acid, e.g. acetic acid or citric acid, alkyl sulfonic acid as methane sulfonic acid, methane-disulfonic acid, methane-trisulfonic acid, aryl sulfonic acid as tosylate compounds, and metal salts thereof have a deteriorate effect of the deposition. It was observed that the addition of an anionic agent will prevent or defer the release of the metal ions to be deposited from functionalized urea derivatives—metal ion complex.
According to a third aspect the present invention is further directed to a method for the electroless deposition of a metal or metal alloy on a metal surface of a metal substrate, the method comprising the steps:
According to a fourth aspect the present invention is further directed to a method for the electroless deposition of a metal or metal alloy on a metal surface of a substrate, the method comprising the steps:
The method according to the third and fourth aspect ensures an efficient deposition process.
A method of the present invention is preferred, wherein the method is performed at a temperature from 20° C. to 100° C., preferably from 30° C. to 80° C., more preferably from 40° C. to 70° C., or 40° C. to 60° C., most preferably at 50° C. to 60° C., or at 50° C.
By performing the method at the preferred temperature ranges, a highly efficient deposition reaction can be ensured.
A method of the present invention is preferred, wherein the substrates to be treated comprise metal substrates, wherein preferably the metal substrates or substrates comprising metal surfaces comprise all metals and metal alloys used for immersion deposition (e.g. silicon, titanium, tantalum and zirconium therefore are excluded) which are less noble than gold and less noble than the metal to be deposited according to their electrochemical standard potential (measured against hydrogen by known methods), preferably with the exception of iron, chromium, and nickel-chromium steel alloys.
A method of the present invention is preferred, wherein the substrates to be treated comprise metals or metal alloys selected from the group consisting of aluminum, copper, nickel, cobalt, manganese, zinc, lead, antimony, tin, rare earth metals, for example neodymium, copper-zinc alloy, copper-tin alloy, copper-nickel alloy, and aluminum-magnesium alloy.
A method of the present invention is preferred, wherein the metal or metal surfaces of the substrates to be treated comprise copper, nickel, zinc, aluminum, zinc-coated steel and/or cobalt.
Thereby, the deposition efficiency of the method is adjusted to allow for an efficient deposition of a huge variety of metal substrates.
In some cases, a method of the present invention is particularly preferred, wherein the substrate and the metal surface thereof comprise, preferably are, aluminum or an aluminum alloy. This is most preferred if the metal and metal alloy, respectively, for electroless deposition comprises, preferably is, nickel, manganese, copper, and/or alloys thereof.
A method of the present invention is preferred, wherein during method step (B) no voltage is applied to the substrate. This means that no electrical current is involved as electron donor for reducing metal ions to the metal or metal alloy upon electroless deposition.
Furthermore, a method of the present invention is preferred, wherein the aqueous alkaline deposition composition is substantially free of, preferably does not comprise, a reducing agent for the electroless deposition of the metal and metal alloy, respectively, most preferably if the metal and metal alloy, respectively, is or comprises nickel and/or manganese. This preferably also applies generally to the aqueous alkaline deposition composition of the present invention. Thus, a conventional, e.g. chemical compound for reducing the metal and metal alloy, respectively, is preferably not needed.
Instead, a method of the present invention is most preferred, wherein the electroless deposition is an immersion deposition. This means that said deposition comprises a redox reaction involving said metal or metal alloy (preferably the metals or metal alloys as defined throughout the present text, more preferably nickel, manganese, and respective alloys thereof) and the surface of the substrate (preferably aluminum or aluminum alloy). In other words, the immersion deposition includes an electron transfer between at least two metals, meaning an electron transfer from a less noble metal to a more noble metal. “more noble metal” means view of the electrochemical series in this context that the redox potential of the complex of metal ions to be deposited and the functionalized urea derivatives is more noble than the metal of the metal surface, e.g. manganese ions complexed by the inventive functionalized urea derivatives are found to be more noble than the metallic zinc substrate. In the context of the present invention, the substrate (including its surface) and its metal surface thereof, is not considered as a reducing agent, but is part of the redox reaction between metal of metal surface and metal ions to be plated. Typically, such type of metal deposition is called immersion deposition. Also typically, such a metal deposition is preferably self-limiting because the more metal or metal alloy is deposited and thereby covering the substrate surface, the less access is provided to the surface metal to drive the process forward.
Thus, preferred is a method of the present invention, wherein the metal and metal alloy for deposition is different from the substrate, more specially from the metal or metal surface of the substrate.
During the use of the deposition composition to deposit metal on the metal surface, the concentration of the metal ions of the metal surface of the substrate rises in the deposition composition while the concentration of the metal ions derived from the source of metal ions declines. The accumulates metal ions derived from the metal surface of the substrate (or metal substrate) build precipitates and sink to the button of the depositing tank.
A method of the present invention is therefore preferred, wherein the method comprises the further step:
The occurring precipitate can be removed from the solution by filtration or other comparable methods.
Additionally the decrease in metal concentration in the deposition composition due to the deposition of metal on the surface of the substrate can be counterbalanced by adding more metal source into the deposition composition, for example by adding elemental metal (solid metal pieces) in case of the method according to the third aspect, or for example by addition metal salt or by applying anodic oxidation in case of the method according to the fourth aspect.
A method of the present invention is preferred, wherein precipitates formed in the aqueous alkaline deposition composition during optionally method step (C1) are removed from the aqueous alkaline deposition composition during method step (C2) to obtain a precipitate-reduced filtered aqueous alkaline deposition composition after method step (C2). The increased temperature promotes the building of the precipitates.
If temperature is optionally increased, a method of the present invention is preferred, wherein the method is performed at a temperature from 20° C. to 100° C., preferably from 30° C. to 80° C., more preferably from 40° C. to 70° C. or 40° C. to 60° C., even more preferably at 50° C. to 60° C., most preferably at 50° C.
By removing the precipitates from the aqueous alkaline deposition composition, the metal ions, which have been removed from the treated metal surface, can be efficiently recovered.
By adding a source of metal ions according to method step (C3) the aqueous alkaline deposition composition can be replenished with metal ions to be deposited. The replenished and filtered aqueous alkaline deposition composition is than reapplied to method step (A).
A method of the present invention is preferred, wherein the metal substrate provided during step (A) is formed as a flexible metal substrate, preferably as a flexible copper substrate, more preferably as a flexible copper-coated polymer.
In some other cases, a flexible foil is preferred, most preferably an aluminum foil. This is most preferred, if the metal and metal alloy, respectively, for electroless deposition is or comprises nickel.
A method of the present invention is preferred, wherein the substrate provided during step (A) is formed as a copper-coated laminate or resin, or a uniform copper substrate.
By depositing metal or metal alloys on different kind of substrates with different chemical and physical properties the method can be applied in a wide scope of applications and is therefore generally usable.
For example, for printed circuit boards (PCBs) a copper-coated resin, in particular polymer, can be used or a copper-coated glass can be used as substrates. Alternatively, for general manufacturing goods, copper-coated plastics or copper-coated sheet metal can be used as substrates.
A method of the present invention is preferred, wherein step (A) and/or (B) is performed under stirring, preferably at a stirring rate from 20 rpm to 1.000 rpm, more preferably from 50 rpm to 500 rpm, and most preferably at 100 rpm.
A method of the present invention is preferred, wherein step (B) is performed for a duration less than 2 hours, preferably less than 1 hour, more preferably less than 45 min, even more preferably less than 30 min, and most preferably less than 15 min.
A method of the present invention is preferred, wherein step (B) is performed for a duration from 1 min to 2 hours, preferably from 5 min to 1.5 hours, more preferably from 15 min to 1 hour and most preferably from 50 min to 15 min.
The preferred stirring and time intervals of the method allow for an efficient deposition, which can be individually adjusted according to the used metal substrate.
A method of the present invention is preferred, wherein the method comprises a step (P), which is performed prior to step (B), wherein step (P) comprises:
By pre-rinsing the substrate with the acidic solution and a subsequent washing step, an efficient cleaning of the surface on which the metal is deposited during step (B) can be ensured, thereby increasing the effectivity of the method. By pre-rinsing the substrate any potential corrosion of the substrate and/or surface contaminations of the substrate can be efficiently removed before transferring the substrate into the aqueous alkaline deposition composition.
However, method step (P) is an optional method step, and the method according to the third and/or fourth aspect the present invention can be also performed without method step (P).
Preferably, the aforementioned regarding the aqueous alkaline deposition composition according to the first and second aspect of the present invention, preferably what is described as being preferred, applies likewise to the method according to the third and fourth aspect of the present invention.
In a very preferred specific aspect, the method of the present invention refers to an electroless immersion nickel deposition (i.e. without an individual reducing agent), wherein the aqueous alkaline deposition composition comprises nickel ions for electroless depositing nickel or a nickel alloy on aluminum or an aluminum alloy.
Preferably, in this specific aspect, the method of the present invention does not include a pre-treatment of the aluminum and aluminum alloy, respectively, with a pre-treatment composition comprising fluoride prior to step (B),
Preferably, in this specific aspect, the method of the present invention does not include a pre-treatment of the aluminum and aluminum alloy, respectively, with a pre-treatment composition comprising zinc prior to step (B),
Own experiments have shown that this specific aspect allows a significant reduction in pre-treatment effort compared to common plating on aluminum/aluminum alloy procedures. In many cases, an otherwise typical pre-treatment including more than one contacting with a pre-treatment composition comprising fluoride and/or zinc, typically known as zincate-pre-treatment, can be avoided. Rather, the compounds of formula I and salts thereof allow not only for an effective stabilization of the nickel ions in the aqueous alkaline deposition composition but also provide a pre-treatment effect on the aluminum/aluminum alloy surface by at least partly dissolving the detrimental passivation layer thereon.
Preferably, in this specific aspect, the method of the present invention does not include a pre-treatment of the aluminum and aluminum alloy, respectively, with a pre-treatment composition comprising nitric acid prior to step (B).
In this specific aspect, a method of the present invention is preferred, wherein in step (B) the deposited nickel or nickel alloy has a layer thickness ranging from 4 nm to 100 nm, preferably from 7 nm to 80 nm, more preferably from 10 nm to 60 nm, even more preferably from 15 nm to 40 nm, most preferably from 20 nm to 30 nm.
In this specific aspect, a method of the present invention is preferred, wherein step (B) is carried out for a time ranging from 1 minutes to 120 minutes, preferably from 1.5 minutes to 100 minutes, more preferably from 2 minutes to 80 minutes even more preferably from 2.5 minutes to 70 minutes, most preferably from 5 minutes to 15 minutes.
In this specific aspect, preferred is a method of the present invention comprising after step (B), step
Thus, in step (B-1) a further nickel or nickel alloy is electroless deposited on the nickel and nickel alloy, respectively, deposited by immersion deposition in step (B).
As a result, in steps (B) and (B-1) two consecutive nickel layers are deposited on each other.
Preferably, the aforementioned regarding the first and second aspect of the present invention applies likewise to the aforementioned specific aspect.
Preferably, the nickel and nickel alloy to be electroless deposited are either from nickel ions or metallic nickel as nickel source, most preferably from metallic nickel. Since compounds (a) dissolve metallic nickel such that nickel ions are formed, no additional counterion are added to the aqueous alkaline deposition composition. This is of great benefit.
According to a fifth aspect the present invention is further directed to a metal substrate with a deposited metal or metal alloy layer on the surface of the substrate, wherein the deposited metal or metal alloy layer has been obtained by a method for the electroless deposition of a metal or metal alloy on a surface of a substrate according to the third of fourth aspect.
Preferably, the aforementioned regarding the use of the aqueous alkaline deposition composition according to the first and second aspect of the present invention and the method according to the third and fourth aspect of the present invention, preferably what is described as being preferred, applies likewise to the substrate according to the fifth aspect of the present invention.
Preparation of the Aqueous Alkaline Silver Deposition Composition 25.00 g (0.232 mol) of silver powder and a magnetic stir bar were placed in a 2000 ml beaker. Then 200.00 g (0.724 mol) of 1,3-bis(3-(1H-imidazol-1yl)propyl)urea was added and was dissolved in 1775 ml of deionized water. Stirring was carried out for 5 hours at 50° C. at a speed of 150 rpm. At the end of the reaction time, the liquid portion had turned blue-violet. Small amounts of undissolved silver powder were still at the bottom of the beaker. Water, which was evaporated during the 5 hours reaction time, was replenished with deionized water. The obtained yield is 2000.00 g (100.00%). After preparation, the aqueous alkaline silver deposition composition has a pH between 9 and 11 and is ready for the electroless deposition of silver on surfaces of substrates.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. The aqueous alkaline silver deposition composition was then transferred to a 2000 ml graduated cylinder with a magnetic stir bar. The copper-plated ABS substrate was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and immediately coated by immersing the copper-plated ABS substrate in the aqueous alkaline silver deposition composition at 50° C. for 15 minutes. The composition was stirred at about 150 rpm during coating. After coating, the copper-plated ABS substrate was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thickness as 0.084 μm.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. The copper sheet was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and immediately coated by immersing the copper sheet in the aqueous alkaline silver deposition composition at 50° C. for 15 minutes. The composition was stirred at about 150 rpm during coating. After coating, the copper sheet was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thickness as 0.089 μm. The silver surface did not tarnish over time. After 12 weeks no tarnishing could be found. Also fingerprints did not remain on the surface or could be wiped away easily.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. The brass sheet was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and immediately coated by immersing the brass sheet in the aqueous alkaline silver deposition composition at 50° C. for 15 minutes. The composition was stirred at about 150 rpm during coating. After coating, the brass sheet was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thickness as 0.128 μm.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. The copper-plated FR4 panel was immersed in 5% sulfuric acid for 10 seconds, then rinsed with a lot of deionized water and coated immediately by immersing the copper-plated FR4 panel in the aqueous alkaline silver deposition composition at 50° C. for 15 minutes. The composition was stirred at about 150 rpm during coating. After coating, the copper-plated FR4 panel was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thickness as 0.775 μm.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. The copper-plated HMP panel was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and immediately coated by immersing the copper-plated HMP panel in the aqueous alkaline silver deposition composition for 15 minutes at 50° C. with an immersion depth of 25%, for another 15 minutes with an immersion depth of 50% and for another 15 minutes at 50° C. with an immersion depth of 75%. The composition was stirred at about 150 rpm during coating. After coating, the copper-plated HMP panel was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thicknesses after 15 minutes as 0.087 μm, after 30 minutes as 0.141 μm and after 45 minutes as 0.178 μm.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. The copper-plated HMP panel was immersed in 5% sulfuric acid for 10 seconds, then rinsed with a lot of deionized water and immediately coated by immersing the copper-plated HMP panel in the aqueous alkaline silver deposition at 50° C. for 20 hours at an immersion depth of 75%. The composition was stirred at about 150 rpm during coating. After coating, the copper-plated HMP panel was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thickness as 0.428 μm.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. The copper-plated glass panel was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and immediately coated by immersing the copper-plated glass panel in the aqueous alkaline silver deposition composition at 50° C. for 5 minutes. The composition was stirred at about 150 rpm during coating. After coating, the copper-plated glass panel was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thickness as 0.059 μm.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. A copper-plated piece of a wafer was immersed in 5% sulfuric acid for 10 seconds, then rinsed with a lot of deionized water and immediately coated by immersing the copper-plated piece of the wafer in the aqueous alkaline silver deposition composition at 50° C. for 5 minutes. The immersion depth was 95%. The composition was stirred at approximately 150 rpm during coating. After coating, the wafer piece was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thickness as 0.137 μm.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. The high-frequency aluminum socket was immersed in 5% sulfuric acid for 15 seconds until an area-wide gas evolution started. The high-frequency aluminum socket was then rinsed with plenty of deionized water and immediately coated by immersing the high-frequency aluminum socket in the aqueous alkaline silver deposition composition for 5 minutes at 50° C., while the composition was stirred at approximately 150 rpm during coating. After coating, the high-frequency aluminum socket was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thickness as 0.085 μm.
2000 g of the aqueous alkaline silver deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker for 20 minutes at a stirring rate of 150 rpm. The high-frequency aluminum socket was immersed in 5% sulfuric acid for 15 seconds until an area-wide gas evolution started. The high-frequency aluminum socket was then rinsed with plenty of deionized water and immediately coated by immersing the high-frequency aluminum socket in the aqueous alkaline silver deposition composition for 15 minutes at 50° C., while the composition was stirred at approximately 150 rpm. After coating, the high-frequency aluminum socket was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the silver layer thickness as 0.352 μm.
The aqueous alkaline silver deposition composition as prepared above deposits translucent to opaque, matte to shiny silver layers on a variety of different substrates as used above, which do no longer tarnish over time. Silver deposit layers of 0.05 μm to 0.75 μm are obtained at temperatures between 30° C. to 50° C. after a coating time from 5 minutes to 60 minutes.
During the use of the deposition composition the concentration of the metal ions of the metal surface of the substrate (as explained in the example above) rises in the deposition composition while the concentration of the available silver ions derived from the source of silver ions declines.
For recycling of the deposition composition or parts thereof, the deposition composition was filtered to separate precipitates of the metal ions derived from the metal surface. The filtered aqueous alkaline deposition composition was replenished by adding silver powder in principle as described under preparation of the aqueous alkaline silver deposition composition above. In consequence, the silver powder is dissolved and thus provides the silver ions. The silver ions will be complexed by the compound as mentioned above. Finally, the replenished and filtered aqueous alkaline deposition composition will be used again in method step (A).
25.00 g (0.426 mol) of nickel anode spheres (diameter approximately 8 mm) and a small magnetic stir bar were carefully placed at the bottom of a 2000 ml beaker. Then 200.00 g (0.724 mol) of 1,3-bis(3-(1H-imidazol-1yl)propyl)urea was added and was dissolved in 1775 ml of deionized water. The composition was stirred for 168 hours at 50° C., at a speed of 150 rpm such that the nickel anode spheres are not moved. At the end of the reaction time, the composition had turned blue-green. Small amounts of undissolved nickel anode spheres were still at the bottom of the beaker. Water, which was evaporated during the 168 hours reaction time, was replenished with deionized water. The obtained yield was 2000.00 g (100.00%). After preparation, the aqueous alkaline nickel deposition composition has a pH between 9 and 11 and is ready for the electroless deposition of nickel on a surface of a substrate.
2000 g of the aqueous alkaline nickel deposition composition as prepared above were heated to 40° C. in a 2000 ml beaker for 60 minutes at a stirring rate of 150 rpm. The zinc galvanized steel sheet was immersed in 5% sulfuric acid for 15 seconds until an area-wide gas evolution started. The zinc galvanized steel sheet was then rinsed with plenty of deionized water and immediately coated by immersing the zinc galvanized steel sheet in the aqueous alkaline nickel deposition composition at 40° C. for 60 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the zinc galvanized steel sheet was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the nickel layer thickness as 0.018 μm.
2000 g of the aqueous alkaline nickel deposition composition as prepared above were heated to 60° C. in a 2000 ml beaker for 50 minutes at a stirring rate of 150 rpm. The zinc galvanized steel sheet was immersed in 5% sulfuric acid for 15 seconds until an area-wide gas evolution started. The zinc galvanized steel sheet was then rinsed with plenty of deionized water and immediately coated by immersing the zinc galvanized steel sheet in the aqueous alkaline nickel deposition composition at 60° C. for 60 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the zinc galvanized steel sheet was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the nickel layer thickness as 0.029 μm.
1000 g of the aqueous alkaline nickel deposition composition as prepared above were heated to 60° C. in a 2000 ml beaker for 38 minutes at a stirring rate of 150 rpm. The aluminum connector was directly coated, by immersing the aluminum connector in the aqueous alkaline nickel deposition composition at 60° C. for 15 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the aluminum connector was rinsed clear with deionized water and dried with compressed air. FIB analysis determined the nickel layer thickness as 0.013 μm.
Electroless deposition of nickel on a surface of an aluminum connector, followed by a chemical deposition (i.e. with the help of a reducing agent) of nickel on a surface of an aluminum connector.
1000 g of the aqueous alkaline nickel deposition composition as prepared above were heated to 60° C. in a 2000 ml beaker for 38 minutes at a stirring rate of 150 rpm. The aluminum connector was directly coated, by immersing the aluminum connector in the aqueous alkaline nickel deposition composition at 60° C. for 15 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the aluminum connector was rinsed clear with deionized water and dried with compressed air.
500 g of an aqueous chemical nickel deposition composition (Nichem MP 1188 available by Atotech Deutschland GmbH) were heated to 88° C. in a 1000 ml beaker for 44 minutes at a stirring rate of 150 rpm. The nickel immersion coated aluminum connector was directly coated, by coating the nickel immersion coated aluminum connector in the aqueous chemical nickel deposition composition at 88° C. for 20 minutes. The composition was not stirred during coating. After coating, the nickel immersion and chemical nickel coated aluminum connector was rinsed clear with deionized water and dried with compressed air. FIB analysis determined the immersion nickel layer thickness as 0.016 μm.
In a 1000 ml beaker with magnetic stirring bar, 250 ml deionized water was added, then with vigorous stirring, first 5.50 g nickel(II)sulfate and then 15.00 g ammonium chloride were added. The light green solution was stirred at approximately 150 rpm. The light green solution was mixed with deionized water to a volume of 500 ml and heated to 60° C. for 37 minutes. The aluminum connector was directly coated, by immersing the aluminum connector in the aqueous chemical nickel deposition composition at 60° C. for minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the aluminum connector was rinsed clear with deionized water and dried with compressed air. FIB analysis determined the nickel layer thickness as 0.032 μm. The obtained Ni immersion layer shows poor homogeneity and defects.
The aqueous alkaline nickel deposition composition deposits translucent to opaque, matte to bright nickel layers on aluminum, zinc, and tin substrates. Depending on the surface properties of the base material, these can be matte to highly polished. Nickel deposit layers of 0.02 μm to 0.03 μm are obtained in 60 minutes, at temperatures from 40° C. to 60° C., which do no longer tarnish over time.
During the use of the deposition composition the concentration of the metal ions of the metal surface of the substrate (as explained in the example above) rises in the deposition composition while the concentration of the available nickel ions derived from the source of nickel ions declines.
For recycling of the deposition composition or parts thereof, the deposition composition was filtered to separate precipitates of the metal ions derived from the metal surface. The filtered aqueous alkaline deposition composition was replenished by adding nickel powder in principle as described under preparation of the aqueous alkaline nickel deposition composition above. In consequence, the nickel powder is dissolved and thus provides the nickel ions. The nickel ions will be complexed by the compound as mentioned above.
Finally, the replenished and filtered aqueous alkaline deposition composition will be used again in method step (A).
25.00 g (0.455 mol) of manganese pieces and a small magnetic stir bar were carefully placed on the bottom of a 2000 ml beaker. Then 200.00 g (0.724 mol) of 1,3-bis(3-(1H-imidazol-1yl)propyl)urea was added and was dissolved in 1775 ml of deionized water. Stirring was carried out for 60 hours at 30° C. at a speed of 150 rpm. It was prevented that the temperature of the composition rises above 40° C., to avoid an uncontrollable autocatalytic reaction, in which the manganese would dissolve exothermically with strong hydrogen evolution. At the end of the stirring, the liquid composition had turned light blue. Small amounts of undissolved manganese pieces were still at the bottom of the beaker. Water, which was evaporated during the 60 hours reaction time, was replenished with deionized water. The obtained yield was 2000.00 g (100.00%). After preparation, the aqueous alkaline manganese deposition composition has a pH between 9 and 11 and is ready for the electroless deposition of manganese on a surface of a substrate.
2000 g of the aqueous alkaline manganese deposition composition as prepared above were heated to 30° C. in a 2000 ml beaker for 35 minutes at a stirring rate of 150 rpm. A zinc galvanized steel sheet measuring 70×12×0.2 mm was immersed in 5% sulfuric acid for 15 seconds until an area-wide gas evolution started. The zinc galvanized steel sheet was then removed, rinsed with plenty of deionized water and immediately coated by immersing the zinc galvanized steel sheet in the aqueous alkaline manganese deposition composition at 30° C. for 60 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the zinc galvanized steel sheet was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the manganese layer thickness as 0.012 μm.
2000 g of the aqueous alkaline manganese deposition composition as prepared above were heated to 30° C. for 18 minutes in a 2000 ml beaker at a stirring rate of 150 rpm. A zinc galvanized steel sheet measuring 70×70 mm was immersed in 5% sulfuric acid for 10 seconds until gas evolution started over the entire area. The zinc galvanized steel sheet was then removed, rinsed with plenty of deionized water and immediately coated by immersing the zinc galvanized steel sheet in the aqueous alkaline manganese deposition composition at 30° C. for 90 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the zinc galvanized steel sheet was rinsed with deionized water and dried with compressed air. XRF analysis determined the manganese layer thickness as 0.111 μm.
500 g of the aqueous alkaline manganese deposition composition as prepared above were heated to 30° C. in a 1000 ml beaker for 12 minutes at a stirring rate of 150 rpm. The aluminum connector was directly coated, by immersing the aluminum connector in the aqueous alkaline manganese deposition composition at 30° C. for 15 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the aluminum connector was rinsed clear with deionized water and dried with compressed air. FIB analysis determined the manganese layer thickness as 0.019 μm.
500 g of the aqueous alkaline manganese deposition composition as prepared above were heated to 30° C. in a 1000 ml beaker for 12 minutes at a stirring rate of 150 rpm. The aluminum connector was directly coated, by immersing the aluminum connector in the aqueous alkaline manganese deposition composition at 30° C. for 15 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the aluminum connector was rinsed clear with deionized water and dried with compressed air.
500 g of an aqueous chemical nickel deposition composition (Nichem MP 1188 available by Atotech Deutschland GmbH) were heated to 88° C. in a 1000 ml beaker for 44 minutes at a stirring rate of 150 rpm. The nickel immersion coated aluminum connector was directly coated, by coating the nickel immersion coated aluminum connector in the aqueous chemical nickel deposition composition at 88° C. for 20 minutes. The composition was not stirred during coating. After coating, the manganese immersion and chemical nickel coated aluminum connector was rinsed clear with deionized water and dried with compressed air. FIB analysis determined the nickel layer thickness as 0.015 μm.
The aqueous alkaline manganese deposition composition deposits translucent to opaque, gray to pinkish manganese layers on aluminum and zinc, which become silver-colored when heated strongly. Depending on the surface condition of the aluminum or zinc surface, the deposit layers can be dull to highly polished. Manganese layers of 0.01 μm are obtained at 30° C. in 60 minutes.
During the use of the deposition composition the concentration of the metal ions of the metal surface of the substrate (as explained in the example above) rises in the deposition composition while the concentration of the available manganese ions derived from the source of manganese ions declines.
For recycling of the deposition composition or parts thereof, the deposition composition was filtered to separate precipitates of the metal ions derived from the metal surface. The filtered aqueous alkaline deposition composition was replenished by adding manganese powder in principle as described under preparation of the aqueous alkaline manganese deposition composition above. In consequence, the manganese powder is dissolved and thus provides the manganese ions. The manganese ions will be complexed by the compound as mentioned above. Finally, the replenished and filtered aqueous alkaline deposition composition will be used again in method step (A).
10.10 g (0.170 mol) of cobalt powder and a magnetic stir bar were placed in a 1000 ml beaker. Then, 100.00 g (0.289 mol) of 1,3-bis(3-(1H-imidazol-1yl)propyl)urea (80% wt.-% dissolved in water) was added and was dissolved in 700 ml of deionized water. Stirring was carried out for 24 hours at 50° C. at a speed of 150 rpm. At the end of the reaction time, the composition had turned pink. Small amounts of undissolved cobalt powder were still at the bottom of the beaker. Water, which was evaporated during the 24 hours reaction time, was replenished with deionized water. The obtained yield was 810.10 g (100.00%). After preparation, the aqueous alkaline cobalt deposition composition has a pH between 9 and 11 and is ready for the electroless deposition of cobalt on surfaces of substrates.
2000 g of the aqueous alkaline cobalt deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker at a stirring rate of 150 rpm in 36 minutes. The aluminum perforated plate was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and was immediately coated by immersing the aluminum perforated plate in the aqueous alkaline cobalt deposition composition for 15 minutes at 50° C. with an immersion depth of 90%, for another 15 minutes with an immersion depth of 60% and for another 15 minutes with an immersion depth of 30%. The composition was stirred at about 150 rpm during coating. After coating, the aluminum perforated plate was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the cobalt layer thicknesses as follows: a cobalt layer after 15 minutes was not detectable; a cobalt layer after 30 minutes has a thickness of 0.003 μm and a cobalt layer after 45 minutes has a thickness of 0.011 μm.
2000 g of the aqueous alkaline cobalt deposition composition as prepared above was heated to 50° C. for 39 minutes in a 2000 ml beaker at a stirring rate of 150 rpm. The zinc galvanized steel sheet was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and immediately coated by immersing the zinc galvanized steel sheet in the aqueous alkaline cobalt deposition composition for 15 minutes at 50° C. with an immersion depth of 90%, for another 15 minutes with an immersion depth of 60% and for another 15 minutes with an immersion depth of 30%. The composition was stirred at about 150 rpm during coating. After coating, the zinc galvanized steel sheet was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the cobalt layer thicknesses as follows: cobalt layer after 15 minutes: 0.017 μm, cobalt layer after 30 minutes: 0.024 μm and cobalt layer after 45 minutes: 0.028 μm.
The aqueous alkaline cobalt deposition composition deposits translucent to opaque cobalt layers on aluminum and zinc, which no longer tarnish. The shiny layers shine in all spectral colors depending on the incidence of light. This effect persists even after six months of storage under atmospheric conditions. Depending on the surface condition of the aluminum or zinc surface, the cobalt deposit layers can be matte to highly glossy. Uniformly closed cobalt deposit layers of 0.003-0.028 μm are obtained at 50° C. for 5 minutes to 60 minutes.
During the use of the deposition composition the concentration of the metal ions of the metal surface of the substrate (as explained in the example above) rises in the deposition composition while the concentration of the available cobalt ions derived from the source of cobalt ions declines.
For recycling of the deposition composition or parts thereof, the deposition composition was filtered to separate precipitates of the metal ions derived from the metal surface. The filtered aqueous alkaline deposition composition was replenished by adding cobalt powder in principle as described under preparation of the aqueous alkaline cobalt deposition composition above. In consequence, the cobalt powder is dissolved and thus provides the cobalt ions. The cobalt ions will be complexed by the compound as mentioned above. Finally, the replenished and filtered aqueous alkaline deposition composition will be used again in method step (A).
26.411 g (0.416 mol) of copper foil pieces (approximately 1×1 cm) and a magnetic stir bar were placed in a 3000 ml beaker. Then, 211.29 g (0.765 mol) of 1,3-bis(3-(1H-imidazol-1yl)propyl)urea was added and was dissolved in 2139.31 ml of deionized water. Stirring was carried out for 60 hours at 50° C. at a speed of 150 rpm. At the end of the reaction time, the composition had turned bright blue. Small amounts of undissolved copper foil pieces were still at the bottom of the beaker. Water, which was evaporated during the 60 hours reaction time, was replenished with deionized water. The obtained yield was 2377.01 g (100.00%). After preparation, the aqueous alkaline copper deposition composition has a pH between 9 and 11 and is ready for the electroless deposition of copper on surfaces of substrates.
2000 g of the aqueous alkaline copper deposition composition as prepared above was heated to 50° C. in a 2000 ml beaker at a stirring rate of 150 rpm for 39 minutes. The aluminum perforated plate was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and immediately coated by immersing the aluminum perforated plate in the aqueous alkaline copper deposition composition for 15 minutes at 50° C. with an immersion depth of 90%, for another 15 minutes with an immersion depth of 60% and for another 15 minutes with an immersion depth of 30%. The composition was stirred at about 150 rpm during coating. After coating, the aluminum perforated plate was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the copper layer thicknesses as follows: copper layer after 15 minutes: 0.004 μm, copper layer after 30 minutes: 0.006 μm and copper layer after 45 minutes: 0.007 μm.
2000 g of the aqueous alkaline copper deposition composition as prepared above was heated to 60° C. in a 2000 ml beaker at a stirring rate of 150 rpm in 38 minutes. The aluminum foil was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and immediately coated by immersing the aluminum foil in the aqueous alkaline copper deposition composition for 15 minutes at 60° C. with an immersion depth of 90%, for another 15 minutes at an immersion depth of 60% and for another 15 minutes at an immersion depth of 30%. The composition was stirred at about 150 rpm during coating. After coating, the aluminum foil was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the copper layer thicknesses as follows: copper layer after 15, 30 and 45 minutes: 0.007 μm.
500 g of the aqueous alkaline copper deposition composition as prepared above were heated to 50° C. in a 1000 ml beaker for 25 minutes at a stirring rate of 150 rpm. An aluminum connector measuring 30.7×29.5 mm was rinsed with deoinized water and immersed in 5.00% sulfuric acid for 60 seconds. After 20 seconds an area-wide gas evolution started. The aluminum connector was then removed, rinsed with plenty of deionized water and immediately coated by immersing the aluminum connector in the aqueous alkaline copper deposition composition at 50° C. for 15 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the aluminum connector was rinsed clear with deionized water and dried with compressed air. A homogenous Cu layer was obtained. A copper layer thickness of 16.97 μm was determined by FIB analysis.
1000 g of the aqueous alkaline copper deposition composition as prepared above were heated to 50° C. in a 1000 ml beaker for 25 minutes at a stirring rate of 150 rpm. An aluminum panel measuring 127×44.3×0.6 mm was rinsed with deionized water and immersed in 5.00% sulfuric acid for 60 seconds. After 20 seconds an area-wide gas evolution started. The aluminum panel was then removed, rinsed with plenty of deionized water and immediately coated by immersing the aluminum panel in the aqueous alkaline copper deposition composition at 50° C. for 15 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the aluminum panel was rinsed clear with deionized water and dried with compressed air. An inhomogeneous and porous Cu layer was obtained. A copper layer thickness of 121.92 μm was determined by FIB analysis.
2000 g of the aqueous alkaline copper deposition composition as prepared above was heated to 60° C. in a 2000 ml beaker for 35 minutes at a stirring rate of 150 rpm. The zinc galvanized steel sheet was immersed in 5% sulfuric acid for 10 seconds, then rinsed with plenty of deionized water and immediately coated by immersing the zinc galvanized steel sheet in the aqueous alkaline copper deposition composition for 15 minutes at 60° C. with an immersion depth of 90%, for another 15 minutes at an immersion depth of 60% and for another 15 minutes at an immersion depth of 30%. The composition was stirred at about 150 rpm during coating. After coating, the zinc galvanized steel sheet was rinsed clear with deionized water and dried with compressed air. XRF analysis determined the copper layer thicknesses as follows: copper layer after 15 minutes: 0.023 μm, copper layer after 30 minutes: 0.037 μm and copper layer after 45 minutes: 0.042 μm.
500 g of the aqueous alkaline copper deposition composition as prepared above were heated to 50° C. in a 1000 ml beaker for 26 minutes at a stirring rate of 150 rpm. The aluminum connector was directly coated, by immersing the aluminum connector in the aqueous alkaline copper deposition composition at 50° C. for 15 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the aluminum connector was rinsed clear with deionized water and dried with compressed air. FIB analysis determined the copper layer thickness as 0.017 μm.
500 g of the aqueous alkaline copper deposition composition as prepared above were heated to 50° C. in a 1000 ml beaker for 26 minutes at a stirring rate of 150 rpm. The aluminum connector was directly coated, by immersing the aluminum connector in the aqueous alkaline copper deposition composition at 50° C. for 15 minutes. The composition was stirred at approximately 150 rpm during coating. After coating, the aluminum connector was rinsed clear with deionized water and dried with compressed air.
500 g Cupracid UP600 (available by Atotech Deutschland GmbH) without brightener were added to the 1000 ml beaker under gentle stirring. A 50×70×2 mm titanium grid was used as anode. The aluminum connector was attached to an aluminum wire and immersed for 20 minutes at 20° C. in an acidic copper bath at 3A/dm2. The distance between the aluminum connector and titanium grid was 4 cm. After plating, the immersion copper-coated and electrochemical copper plated connector was rinsed with deionized water and dried with compressed air. The obtained copper layer thickness was very homogeneous and closed.
The aqueous alkaline copper deposition composition deposits translucent to opaque copper layers on aluminum and zinc, which no longer tarnish. Depending on the surface condition of the aluminum or zinc surface, the copper layers can be matte to high-gloss. Uniformly closed layers 0.004-0.042 μm at 50° C. to 75° C. can be obtained from 5 minutes to 60 minutes.
During the use of the deposition composition the concentration of the metal ions of the metal surface of the substrate (as explained in the example above) rises in the deposition composition while the concentration of the available copper ions derived from the source of copper ions declines.
For recycling of the deposition composition or parts thereof, the deposition composition was filtered to separate precipitates of the metal ions derived from the metal surface. The filtered aqueous alkaline deposition composition was replenished by adding copper powder in principle as described under preparation of the aqueous alkaline copper deposition composition above. In consequence, the copper powder is dissolved and thus provides the copper ions. The copper ions will be complexed by the compound as mentioned above. Finally, the replenished and filtered aqueous alkaline deposition composition will be used again in method step (A).
| Number | Date | Country | Kind |
|---|---|---|---|
| 21213534.7 | Dec 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/085252 | 12/9/2022 | WO |
