WO2004111299A2 - Solution and method for ultra thin, non-porous and highly adhesive gold coating - Google Patents
Solution and method for ultra thin, non-porous and highly adhesive gold coating Download PDFInfo
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- WO2004111299A2 WO2004111299A2 PCT/IL2004/000513 IL2004000513W WO2004111299A2 WO 2004111299 A2 WO2004111299 A2 WO 2004111299A2 IL 2004000513 W IL2004000513 W IL 2004000513W WO 2004111299 A2 WO2004111299 A2 WO 2004111299A2
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- WO
- WIPO (PCT)
- Prior art keywords
- gold
- coating
- group
- copper
- substrate
- Prior art date
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- 238000000576 coating method Methods 0.000 title claims abstract description 43
- 239000011248 coating agent Substances 0.000 title claims abstract description 35
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 title claims abstract description 31
- 229910052737 gold Inorganic materials 0.000 title claims abstract description 31
- 239000010931 gold Substances 0.000 title claims abstract description 31
- 238000000034 method Methods 0.000 title claims description 28
- 239000000853 adhesive Substances 0.000 title description 3
- 230000001070 adhesive effect Effects 0.000 title description 3
- 239000000203 mixture Substances 0.000 claims abstract description 13
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 9
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 7
- 238000010668 complexation reaction Methods 0.000 claims abstract description 7
- JAJIPIAHCFBEPI-UHFFFAOYSA-N 9,10-dioxoanthracene-1-sulfonic acid Chemical compound O=C1C2=CC=CC=C2C(=O)C2=C1C=CC=C2S(=O)(=O)O JAJIPIAHCFBEPI-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000000758 substrate Substances 0.000 claims description 18
- 238000007654 immersion Methods 0.000 claims description 17
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 10
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 7
- 229910052709 silver Inorganic materials 0.000 claims description 7
- 239000004332 silver Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 229910045601 alloy Inorganic materials 0.000 claims description 6
- 239000000956 alloy Substances 0.000 claims description 6
- 239000002638 heterogeneous catalyst Substances 0.000 claims description 6
- 238000009472 formulation Methods 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- 239000002537 cosmetic Substances 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- 229910000570 Cupronickel Inorganic materials 0.000 claims description 2
- 229910018828 PO3H2 Inorganic materials 0.000 claims description 2
- 239000002253 acid Substances 0.000 claims description 2
- 125000000217 alkyl group Chemical group 0.000 claims description 2
- 125000004103 aminoalkyl group Chemical group 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 239000010949 copper Substances 0.000 claims description 2
- YOCUPQPZWBBYIX-UHFFFAOYSA-N copper nickel Chemical compound [Ni].[Cu] YOCUPQPZWBBYIX-UHFFFAOYSA-N 0.000 claims description 2
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 claims description 2
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 claims description 2
- 239000001257 hydrogen Substances 0.000 claims description 2
- 229910052739 hydrogen Inorganic materials 0.000 claims description 2
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims description 2
- 125000002768 hydroxyalkyl group Chemical group 0.000 claims description 2
- 239000011859 microparticle Substances 0.000 claims description 2
- 239000002105 nanoparticle Substances 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 239000000243 solution Substances 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 9
- 239000002184 metal Substances 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- 239000003054 catalyst Substances 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- 238000007772 electroless plating Methods 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 2
- XWULEGJMNMPRCI-UHFFFAOYSA-N [bis(phosphonooxymethyl)amino]methyl dihydrogen phosphate Chemical compound OP(O)(=O)OCN(COP(O)(O)=O)COP(O)(O)=O XWULEGJMNMPRCI-UHFFFAOYSA-N 0.000 description 2
- 230000002421 anti-septic effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 230000001953 sensory effect Effects 0.000 description 2
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical class NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 239000008139 complexing agent Substances 0.000 description 1
- 230000001010 compromised effect Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 229910021505 gold(III) hydroxide Inorganic materials 0.000 description 1
- WDZVNNYQBQRJRX-UHFFFAOYSA-K gold(iii) hydroxide Chemical compound O[Au](O)O WDZVNNYQBQRJRX-UHFFFAOYSA-K 0.000 description 1
- 239000012456 homogeneous solution Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 239000002674 ointment Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000008194 pharmaceutical composition Substances 0.000 description 1
- 239000000825 pharmaceutical preparation Substances 0.000 description 1
- 229940127557 pharmaceutical product Drugs 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 150000003378 silver Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/31—Coating with metals
- C23C18/42—Coating with noble metals
- C23C18/44—Coating with noble metals using reducing agents
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/1601—Process or apparatus
- C23C18/1633—Process of electroless plating
- C23C18/1635—Composition of the substrate
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/54—Contact plating, i.e. electroless electrochemical plating
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/22—Secondary treatment of printed circuits
- H05K3/24—Reinforcing the conductive pattern
- H05K3/244—Finish plating of conductors, especially of copper conductors, e.g. for pads or lands
Definitions
- the present invention relates to new method for gold coating on metal surfaces. More particularly the present invention relates to a new composition for immersion coating of gold onto a metallic substrate, methods utilizing the same and products produced thereby.
- the unique method of the present invention involves exposure of the metallic substrates to a solution that contains a soluble gold salt, a complexant and a special reducing agent.
- a highly adhesive, non -porous gold coating with various thicknesses can be prepared by this new approach.
- This new coating method can also be used for discrete coating of various metallic substrates having large surface areas such as ultra fine (nano- and micron scale) powders and thin wires.
- the resulted coated powders and wires can be used as heterogeneous catalysts for CO oxidation and other chemical reactions. Description of the related art
- Immersion gold deposition gives coatings of required quality.
- gold adheres to the metal surface through electromotive potentials generated internally by chemical interaction and not by an external force generated by an electric current.
- the coating of gold is as uniform as the surface.
- the process continues as long as part of the metal surface remains uncovered, since metal cations are essentially liberated from this surface to the solution.
- This method provides maximum coating density i.e. the coating is non-porous at the minimum coating thickness, and therefore gives a coating with the physical properties required for decorative purposes.
- Typical thickness of immersion coatings is 0.05-1 ⁇ m.
- composition for gold coating comprising: a) a water soluble gold salt; b) a complexation agent; and c) a tri-substituted reducing agent of the formula NX 3 wherein all of the x's are the same and are reducing moieties.
- said moiety x is selected from the group consisting of CH 2 PO 3 H 2 , CSNH 2 and CH 2 CH 2 S 2 O 2 Na.
- said gold is deposed on a substrate material selected from the group consisting of copper, nickel, silver, an alloy of copper-tin, an alloy of copper-zinc, an alloy of copper-nickel and stainless steel.
- said gold is deposed on a substrate having a form selected from the group consisting of a plate, an ultra-thin wire, micro-particles and nano-particles.
- said complexation agent is a compound of the formula 1
- each of R 1 , R 2 , R 3 and R 4 are each independently selected from the group consisting of hydrogen, alkyl, hydroxyalkyl, aminoalkyl, and alkylcarboxylic acid.
- a method for providing a non-porous gold coating having a thickness of about 0.03-1 O ⁇ m on a metallic substrate comprising immersing said substrate in an immersion solution at a temperature of between about 50-90 0 C in the presence of an immersion solution comprising a water soluble gold salt; a complexation agent; and a tri-substituted reducing agent of the formula NX 3 wherein all of the x's are the same and are reducing moieties for a period of between about 10 and 300 minutes.
- the invention also provides a product whenever produced utilizing the coating method defined above wherein said product is selected from the group consisting of electronic board circuits and devices, jewelry, religious items, adorning items, decorative items, heterogeneous catalysts, sensor devices, and pharmaceutical and cosmetic formulations.
- the present invention provides for the preparation of a heterogeneous catalyst produced by discrete coating of ultra fine powders and thin wires.
- This catalyst is capable of oxidizing CO to CO 2 and may be used in other industrially important chemical processes.
- Most economic methods for catalyst synthesis require co-precipitation of gold hydroxide with metal oxides followed by a calcination step to produce neutral gold particles deposited on a carrier.
- the catalyst presented herein comprises gold particles produced directly in one step. Thus this catalyst is superior to prior art catalysts both with regard to cost and ease of preparation.
- the present invention relates to a gold coating method that in effect performs both immersion and electroless plating directly in one bath.
- Immersion benefits high surface coverage and electroless plating allows a large range of coating thicknesses to be achieved.
- the combination of those techniques becomes possible due to the use of novel reducing agents together with complexing agents such as ethylene diamine derivatives.
- a substrate material is placed into a coating bath preheated to 50-90 0 C for 10- 300 min as required for desirable coating thickness, then washed in water and dried.
- a nickel substrate is inserted in hot (about 7O 0 C) solution that containing 3 g/l of EDTA, 1.25 g/l KAu(CN) 2 and 2 g/l of nitrilo tris(methylene) triphosphoric acid. The duration of the process is 15 minutes. There is produced a nickel substrate having a gold coating wherein the thickness of coating is 0.1 ⁇ m.
- EXAMPLE 3 A silver substrate is inserted in hot (about 85-90 ⁇ C) solution that containing 3 g/l of EDTA, 5 g/l KAu(CN) 2 and 10 g/l of nitrilo tris(methylene) triphosphoric acid. The duration of the process is 120 minutes. There is produced a silver substrate having a gold coating wherein the thickness of coating is 2 ⁇ m.
Landscapes
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrochemistry (AREA)
- Chemically Coating (AREA)
- Paints Or Removers (AREA)
Abstract
The invention provides a composition for gold coating comprising a water-soluble gold salt; a complexation agent; and a tri-substituted reducing agent of the formula NX3 wherein all of the x’s are the same and are reducing moieties.
Description
SOLUTION AND METHOD FOR ULTRA THIN5 NON-POROUS AND HIGHLY ADHESIVE GOLD COATING
The present invention relates to new method for gold coating on metal surfaces. More particularly the present invention relates to a new composition for immersion coating of gold onto a metallic substrate, methods utilizing the same and products produced thereby.
Existing methods allow coating to be made either by immersion technique or by electroless coating. In contradistinction the present invention combines both techniques in situ.
As will be described hereinafter, the unique method of the present invention involves exposure of the metallic substrates to a solution that contains a soluble gold salt, a complexant and a special reducing agent. A highly adhesive, non -porous gold coating with various thicknesses can be prepared by this new approach. This new coating method can also be used for discrete coating of various metallic substrates having large surface areas such as ultra fine (nano- and micron scale) powders and thin wires. The resulted coated powders and wires can be used as heterogeneous catalysts for CO oxidation and other chemical reactions. Description of the related art
Development of economical alternative to gold electroplating originally served two major industries, i.e. the electrical (electronic) industry and the decorative (jewelry) industry.
For decorative purposes high adhesion, hardness and uniform appearance is critical. For this industry the goal was to obtain the thinnest possible coating which never-the-less fulfilled those requirements in order to minimize cost. Immersion gold deposition gives coatings of required quality. During the immersion process gold adheres to the metal surface through electromotive potentials generated internally by chemical interaction and not by an external force generated by an electric current. The coating of gold is as uniform as the surface. The process continues as long as part of the metal surface remains uncovered, since metal cations are essentially liberated from this surface to the solution. When virtually all of the metal surface is coated,
immersion terminates. This method provides maximum coating density i.e. the coating is non-porous at the minimum coating thickness, and therefore gives a coating with the physical properties required for decorative purposes. Typical thickness of immersion coatings is 0.05-1 μm.
In the electrical industry thick, i.e. a coating of about 2-15 μm, is required since the coated surface should have high electric and thermal conductivity. Known immersion procedures cannot provide a coating that thick, since immersion is a self- terminating process. Therefore electroless plating is a method of choice in this case. In this technique initially precipitated gold nuclei catalize reduction of cationic gold by a soluble reductant, i.e. the coating grows on the gold primer. Therefore electroless plating is an autocatalytic process which will continue once it has started and as long as the plating bath contains the proper components such as, metal ions, reducing agents, etc.. In theory, there is no limit to the thickness of metal that can be deposited by this process. However physical properties of the obtained plating are compromised compared to those of the immersion coating, i.e. pure adhesion and high porosivity
Recent development of electronic devices and competition in this field have created a need for coatings with better physical properties and good appearance. Existing solutions for this challenge comprise two stage processes, for example electroless nickel/ immersion gold. As will realized in light of the above state of the art, a one step, in situ, method would be superior to those solutions in terms of cost effectiveness and ease of implementation.
With this state of the art in mind there is now provided according to the present invention a composition for gold coating comprising: a) a water soluble gold salt; b) a complexation agent; and c) a tri-substituted reducing agent of the formula NX3 wherein all of the x's are the same and are reducing moieties.
In preferred embodiment of the present invention said moiety x is selected from the group consisting of CH2PO3H2, CSNH2 and CH2CH2S2O2Na.
Preferably said gold is deposed on a substrate material selected from the group consisting of copper, nickel, silver, an alloy of copper-tin, an alloy of copper-zinc, an alloy of copper-nickel and stainless steel.
Preferable said gold is deposed on a substrate having a form selected from the group consisting of a plate, an ultra-thin wire, micro-particles and nano-particles.
In preferred embodiment of the present invention said complexation agent is a compound of the formula 1
In another aspect of the present invention there is provided a method for providing a non-porous gold coating having a thickness of about 0.03-1 Oμm on a metallic substrate comprising immersing said substrate in an immersion solution at a temperature of between about 50-900C in the presence of an immersion solution comprising a water soluble gold salt; a complexation agent; and a tri-substituted reducing agent of the formula NX3 wherein all of the x's are the same and are reducing moieties for a period of between about 10 and 300 minutes.
The invention also provides a product whenever produced utilizing the coating method defined above wherein said product is selected from the group consisting of electronic board circuits and devices, jewelry, religious items, adorning items, decorative items, heterogeneous catalysts, sensor devices, and pharmaceutical and cosmetic formulations.
Thus as will be realized major application of the invention is in the coating of parts used in manufacturing of electronic devices. Additional applications are preparation of heterogeneous catalysts, gas sensory devices and components for cosmetic and pharmaceutical products.
In addition the present invention provides for the preparation of a heterogeneous catalyst produced by discrete coating of ultra fine powders and thin wires. This catalyst is capable of oxidizing CO to CO2 and may be used in other industrially important chemical processes. Most economic methods for catalyst synthesis require co-precipitation of gold hydroxide with metal oxides followed by a calcination step to produce neutral gold particles deposited on a carrier. The catalyst presented herein comprises gold particles produced directly in one step. Thus this catalyst is superior to prior art catalysts both with regard to cost and ease of preparation.
As is known change in surface potential occurs when a substrate adsorbs to the surface of a heterogeneous catalyst. Preparation of a discrete gold coating on ultra thin, metal wire enables monitoring of this potential change, and this is a principle for development of gas sensory devices.
Several cosmetic and pharmaceutical applications of noble metals have been explored recently. Silver is added to skin care products and it is claimed that such formulations inhibit contamination and aging of the skin due to the antiseptic properties of silver. Gold is superior to silver in terms of antiseptic properties and therefore applicable in the above mentioned formulations. However final gold containing products will be significantly more expensive than silver analogues. This problem can be overcome by ultra thin gold coating of metal powders and use of those powders in ointments and other pharmaceutical formulations.
Thus the present invention relates to a gold coating method that in effect performs both immersion and electroless plating directly in one bath. Immersion benefits high surface coverage and electroless plating allows a large range of coating thicknesses to be achieved. The combination of those techniques becomes possible due to the use of novel reducing agents together with complexing agents such as ethylene diamine derivatives.
While the invention will now be described in connection with certain preferred embodiments in the following examples so that aspects thereof may be more fully understood and appreciated, it is not intended to limit the invention to these particular
embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the scope of the invention as defined by the appended claims. Thus, the following examples, which include preferred embodiments will serve to illustrate the practice of this invention, it being understood that the particulars shown are by way of example and for purposes of illustrative discussion of preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of formulation procedures as well as of the principles and conceptual aspects of the invention. EXAMPLE 1 Preparation of coating solution:
Ingredients listed in Table 2 are dissolved in 900ml of distilled water, and then water is added to bring the final volume of the homogeneous solution to 1000ml.
Table 2 Ingredients and their amounts
Deposition procedure:
A substrate material is placed into a coating bath preheated to 50-900C for 10- 300 min as required for desirable coating thickness, then washed in water and dried. EXAMPLE 2
A nickel substrate is inserted in hot (about 7O0C) solution that containing 3 g/l of EDTA, 1.25 g/l KAu(CN)2 and 2 g/l of nitrilo tris(methylene) triphosphoric acid. The duration of the process is 15 minutes. There is produced a nickel substrate having a gold coating wherein the thickness of coating is 0.1 μm. EXAMPLE 3
A silver substrate is inserted in hot (about 85-90 α C) solution that containing 3 g/l of EDTA, 5 g/l KAu(CN)2 and 10 g/l of nitrilo tris(methylene) triphosphoric acid. The duration of the process is 120 minutes. There is produced a silver substrate having a gold coating wherein the thickness of coating is 2μm. EXAMPLE 4
The procedure of examples 1 and 2 is repeated to produce ultrathin coatings on different metals as set forth in table 3 hereinafter. Table 3 Substrate material, time of immersion and resulting thickness
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative examples and that the present invention may be embodied in other specific forms without departing from the essential attributes thereof, and it is therefore desired that the present embodiments and examples be considered in all respects as illustrative and not restrictive, reference being made to the appended claims, rather than to the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims
1. A composition for gold coating comprising: a) a water soluble gold salt; b) a complexation agent; and c) a tri-substituted reducing agent of the formula NX3 wherein all of the x's are the same and are reducing moieties.
2. A composition according to claim 1 wherein the moiety x is selected from the group consisting of CH2PO3H2, CSNH2 and CH2CH2S2O2Na.
3. A composition according to claim 1 wherein the gold is deposed on a substrate material selected from the group consisting of copper, nickel, silver, an alloy of copper-tin, an alloy of copper-zinc, an alloy of copper-nickel and stainless steel.
4. A composition according to claim 1 wherein the gold is deposed on a substrate having a form selected from the group consisting of a plate, an ultra-thin wire, micro-particles and nano-particles.
5 A composition according to claim 1 wherein said complexation agent is a compound of the formula 1
6. A method for providing a non-porous gold coating having a thickness of about 0.03-1 Oμm on a metallic substrate comprising immersing said substrate in an immersion solution at a temperature of between about 50-900C in the presence of an immersion solution comprising a water soluble gold salt; a complexation agent; and a tri-substituted reducing agent of the formula NX3 wherein all of the x's are the same and are reducing moieties for a period of between about 10 and 300 minutes.
7. A product whenever produced utilizing the coating method of claim 6 wherein said product is selected from the group consisting of electronic board circuits and devices, jewelry, religious items, adorning items, decorative items, heterogeneous catalysts, sensor devices, and pharmaceutical and cosmetic formulations.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL156,442 | 2003-06-15 | ||
| IL15644203A IL156442A0 (en) | 2003-06-15 | 2003-06-15 | Novel solution and method for ultra thin, non-porous and highly adhesive gold coating |
| IL16244204A IL162442A0 (en) | 2004-06-10 | 2004-06-10 | Solution and method for ultra thin, non-porous andhighly adhesive goldcoating |
| IL162,442 | 2004-06-10 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2004111299A2 true WO2004111299A2 (en) | 2004-12-23 |
| WO2004111299A3 WO2004111299A3 (en) | 2005-02-10 |
Family
ID=33554212
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IL2004/000513 WO2004111299A2 (en) | 2003-06-15 | 2004-06-14 | Solution and method for ultra thin, non-porous and highly adhesive gold coating |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2004111299A2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5364460A (en) * | 1993-03-26 | 1994-11-15 | C. Uyemura & Co., Ltd. | Electroless gold plating bath |
| JP4116718B2 (en) * | 1998-11-05 | 2008-07-09 | 日本リーロナール有限会社 | Electroless gold plating method and electroless gold plating solution used therefor |
-
2004
- 2004-06-14 WO PCT/IL2004/000513 patent/WO2004111299A2/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| WO2004111299A3 (en) | 2005-02-10 |
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