CN105229204A - The galvanic deposit of silver and fluoropolymer nanoparticle - Google Patents

Abstract

Provide electroplating composition and for making the electro-plating method of silver or silver alloys and fluoropolymer nanoparticle codeposition.Silver containing fluoropolymer nanoparticle or silver alloys compound coating have the functional performance of enhancing, the frictional coefficient such as reduced.This electroplating composition comprises: (a) comprises the source of silver ions of utilized as silver methane sulfonate (Ag-MSA); B () comprises the complexing agent with nitrogenous heterocyclic compound; C () comprises the pre-mixing dispersed system of fluoropolymer nanoparticle particle and tensio-active agent, described fluoropolymer nanoparticle particle has the median size from about 10nm to about 500nm; (d) comprise the cosurfactant of cationic fluorosurfactants promoting agent, wherein, described composition has the pH value from about 8 to about 14.

Description

The galvanic deposit of silver and fluoropolymer nanoparticle

Technical field

The present invention relates in general to electroplating composition and for making the electro-plating method of silver or silver alloys and fluoropolymer nanoparticle codeposition, to provide the silver or silver alloys compound coating with enhancement function characteristic.

Background technology

Usually, fine silver coating is high connductivity and compares golden hard.For those reasons, these coatings can be particularly suited for electrical connector.But fine silver coating has high frictional coefficient (COF).Therefore, for the electrical connector applied with silver, need high insertion force.In addition, these coatings have poor wearing character (weather resistance of difference).The seriousness of usual coating abrasion increases along with the increase of normal force.Therefore, these characteristics limit the application of fine silver coating in web member purposes.

The coating be made up of fluoropolymer (such as, tetrafluoroethylene (PTFE)) is known hydrophobic material.Be water-repellancy due to water repellent surface and suppress the absorption of ambient moisture, therefore fluoropolymer coating may be used for giving erosion resistance to metallic surface.

The more known method making the money base compound coating galvanic deposit comprising fluoropolymer nanoparticle.Such as, U.S. Patent Application Publication 2010/0294669 (Abys etc.) describes a kind of method that compound coating based on metal (such as, money base) for being contained fluoropolymer nanoparticle by galvanic deposit strengthens surface property (comprising water-repellancy, erosion resistance, hardness, wear resistance and oilness).The electroplating solution of Abys etc. comprises the dispersed system of inorganic silver salt (such as Silver Nitrate or silver suboxide) and the fluoropolymer nanoparticle with surfactant molecule coating.But, by disclosed plating solution for silver-plating such as Abys, limited stability is provided to fluoropolymer particles, in some instances, provide the coating with bad outward appearance.

Still there is demand in method electrolyte composition and production to the money base compound coating on level and smooth, smooth and erosion-resisting surface, the insertion force that this money base compound coating is very suitable for such as needing to reduce is to reduce the purposes of the web member coating of wearing and tearing.In addition, also exist electrolyte composition and high stability and provide the demand of the method for the uniform deposition thing with good appearance in the length of life of plating solution.

Summary of the invention

Usually, the present invention is directed to electroplating composition and for making the silver of compound or silver alloys be coated with the method be deposited upon on substrate.In an aspect, electroplating composition according to the present invention comprises

A () comprises the source of silver ions of utilized as silver methane sulfonate (Ag-MSA);

B () comprises the complexing agent with nitrogenous heterocyclic compound;

C () comprises the pre-mixing dispersed system of fluoropolymer nanoparticle particle and tensio-active agent, this fluoropolymer nanoparticle particle has the median size from about 10nm to about 500nm; With

D () cosurfactant, wherein, said composition has the pH value from about 8 to about 14.

In another aspect, according to of the present invention for making silver or silver alloys compound coating coating method on the surface of a substrate comprise, substrate surface is contacted with electroplating composition and external electrical source is applied to electroplating composition to make compound coating galvanic deposit on substrate surface thus, wherein, compound coating comprises silver or silver alloys and fluoropolymer nanoparticle.

Other objects and feature are obvious by part and part is hereafter being pointed out.

Accompanying drawing explanation

Figure 1A and Figure 1B illustrates the skeleton diagram not utilizing PTFE particle and utilize the coatingsurface after wear testing that is prepared by PTFE particle and the load of applying 50 grams in the process in 500 cycles of sliding respectively.

Fig. 2 illustrates that digestion time for the composition containing the tensio-active agent be allowed a choice is to the figure of PTFE codeposition speed.

Prepared by the electroplating composition that Fig. 3 illustrates the PTFE utilized containing varied concentration and a series of images of coating after two different thermal ageing tests.

Fig. 4 illustrates a series of scanning electronic microscope (SEM) image of the new coating prepared by the electroplating composition of the PTFE containing varied concentration.

Fig. 5 provides the SEM image of the composite silver coating prepared by the plating solution of the PTFE containing 40g/l.

Fig. 6 illustrates the SEM image heating coated surface grain pattern after 168 hours at 125 DEG C.

Fig. 7 illustrates the SEM image heating coated surface grain pattern after 100 hours at 150 DEG C.

Fig. 8 illustrates focused ion beam (FIB) image of the cross section heating the sample selected by after 100 hours at 150 DEG C.

Fig. 9 illustrates the focused ion beam FIB image of the cross section heating the sample selected by after 100 hours at 150 DEG C.

Figure 10 A illustrates the measuring contact resistance figure for new coated substrate (not having aging) prepared in embodiment 5.

Figure 10 B illustrates the amplification selection figure between 1 milliohm and 2 milliohm contact resistances of Figure 10 A.

Figure 10 C illustrates and at 150 DEG C, heats measuring contact resistance figure after 100 hours for coated substrate prepared in embodiment 5.

Figure 10 D illustrates and at 125 DEG C, heats measuring contact resistance figure after 168 hours for coated substrate prepared in embodiment 5.

Figure 10 E illustrates the amplification selection figure between 1 milliohm and 4 milliohm contact resistances of Figure 10 D.

Figure 11 A illustrates for the fine silver coating in copper substrate, with the AES analytical results of profile depth change.

Figure 11 B illustrates the compound coating deposited for the electroplating composition by the PTFE containing 10g/L, with the AES analytical results of profile depth change.

Figure 12 illustrates the image of the substrate coated by embodiment 7.

Embodiment

Usually, the present invention is directed to electroplating composition and for making the electro-plating method of silver or silver alloys and fluoropolymer nanoparticle codeposition, to provide silver or the silver alloys compound coating of the functional performance with enhancing.

One aspect of the present invention provides a kind of electroplating composition and method, which provides the money base compound coating of the frictional coefficient with reduction.The coating with the frictional coefficient of reduction is especially of value to the electrical connector surface of standing insertion force.The web member surface with the frictional coefficient of reduction reduces insertion force and because this reducing the wearing and tearing on web member surface.

Another aspect provides a kind of electroplating composition and the method for depositing silver base composite coating, this money base compound coating provides the erosion resistance of improvement.When money base compound coating is deposited over corrodible surface (such as, copper or copper alloy) upper time, money base compound coating provide the limit copper blocking layer that contacts with oxygen, surface and limit copper diffusion to the surface of silver based coatings, this prevents from forming cupric oxide on the coating surface.The money base compound coating of the erosion resistance of improvement is provided to be particularly suited for electrical contact surface process.

Another aspect of the present invention provides a kind of electroplating composition and the method for depositing silver base composite coating, and this money base compound coating provides the contact resistance stability of improvement even after thermal aging.Contact resistance is the resistance relevant to the interface between being electrically connected.The thermal ageing of known copper and copper alloy surface increases the contact resistance on surface negatively, and this can cause possible electrical connection fault.The money base compound coating maintaining good contact resistance is after thermal aging very gratifying for electrical connector, and need not use independent nickel blocking layer between silver based coatings and copper base substrate.

Another aspect provides the stable electroplating composition for the money base compound coating at electroplating bath solution life period depositing homogeneous and method.Stable electroplating composition is necessary for cost-efficient electroplating operations.

According to the present invention, the source of silver ions generally including (a) for making the money base compound coating electroplating composition be deposited on substrate and comprise the silver salt of sulfonic acid, (b) complexing agent, c () comprises the pre-mixing dispersed system of fluoropolymer nanoparticle and tensio-active agent, and (d) cosurfactant.In addition according to the present invention, method for making the money base compound coating comprising silver and fluoropolymer nanoparticle be deposited on substrate comprises, surface is contacted with electroplating composition, and external electrical source is put on electroplating composition to make compound coating galvanic deposit on metallic surface thus.

Electroplating composition comprises the silver salt of at least one sulfonic acid as source of silver ions, such as, and utilized as silver methane sulfonate (Ag-MSA).Utilized as silver methane sulfonate has been found in alkaline electro plating solution to be stable especially and to be reliable source of silver ions.Therefore, in multiple embodiment, source of silver ions comprises utilized as silver methane sulfonate.In some embodiments, utilized as silver methane sulfonate is primary or unique source of silver ions.Typically, electroplating composition according to the present invention has from about 5g/L to about 300g/L, from about 10g/L to about 200g/L, from about 15g/L to about 200g/L, from about 10g/L to about 100g/L, from about 5g/L to about 50g/L, from about 10g/L to about 50g/L, or from about 20g/L to about 40g/L the concentration of silver ions of (such as, about 30g/L or about 40g/L).

In some embodiments, electroplate liquid can containing other source of silver ions, and this other source of silver ions comprises the inorganic silver salt be selected from silver suboxide, Silver Nitrate and Sulfuric acid disilver salt.In these embodiments, the weight ratio of sulfonic acid silver salt and inorganic silver salt is from about 5:1 to about 1:5, from about 3:1 to about 1:3, or from about 2:1 to about 1:1.

For the deposition of ag alloy layer, electroplating composition can comprise multiple alloying metal ions source, such as, and gold, platinum, bismuth and copper.Preferably, these metals are used with the form of their sulfonate, oxide compound, nitrate or vitriol.

Electroplating composition of the present invention comprises complexing agent.According to many aspects, electroplating composition is without cyanogen.Therefore, in multiple embodiment, complexing agent comprises and has nitrogenous heterocyclic compound.Specifically, this has nitrogenous heterocyclic compound and comprises at least one 5 ring or 6 rings.Nitrogenous heterocyclic example comprise glycolylurea, succinimide, pyridine, dipyridyl, pyrimidine, uridylic, its replace or unsubstituted analogue, its derivative and its combination.In some embodiments, this has nitrogenous heterocyclic compound and is selected from replacement or unsubstituted glycolylurea and replacement or unsubstituted succinimide.In other embodiments, complexing agent comprises succinimide.

In multiple embodiment, complexing agent comprises the hydantoin compound with structural formula I

Wherein, R ¹, R ², R ³, and R ⁴be hydrogen independently, there is 1 alkyl to 5 carbon atoms, there is 1 to the hydroxyalkyl of 5 carbon atoms or replace or unsubstituted aryl.In multiple embodiment, R ¹, R ², R ³, and R ⁴be hydrogen or there is 1 alkyl to 5 carbon atoms (such as, methyl or ethyl) independently.In these and other embodiments, R ¹and R ²all there is 1 alkyl to 5 carbon atoms (such as, methyl or ethyl) and R ³and R ⁴all hydrogen.

In some embodiments, structural formula I is selected from following compound: glycolylurea; 1-methyl hydantoin; 1,3-T10; 5,5-T10; 1-methylol-5,5-T10; 5,5-diphenyl hydantoin; With its mixture.In some embodiments, structural formula I is 5,5-T10.

Typically, electroplating composition contains at least about 50g/L, at least about 60g/L, at least about 70g/L, or at least about the complexing agent (such as, having the hydantoin compound of structural formula I) of 80g/L.In multiple embodiment, electroplating composition contains from about 50g/L to about 300g/L, from about 60g/L to about 280g/L, from about 70g/L to about 250g/L, from about 80g/L to about 250g/L, or from about 80g/L to the complexing agent of about 150g/L.

According to the present invention, electroplating composition comprises fluoropolymer nanoparticle.The small part that is enhanced to of some function surface performances of money base compound coating is codeposition due to silver or silver alloys and fluoropolymer nanoparticle.The fluoropolymer nanoparticle being less than visible wavelength by making to have median size is incorporated in money base compound coating of the present invention, obtain function surface performance (the such as water-repellancy of enhancing, erosion resistance, wear resistance and oilness) and do not affect the outward appearance of coating.In other words, the electro-deposition method of bright, the smooth coating of acquisition containing fluoropolymer nanoparticle obtains bright, the smooth coating containing fluoropolymer nanoparticle.

Fluoropolymer particles can be selected from tetrafluoroethylene (PTFE), the ethylene-propylene copolymer (FEP) fluoridized, perfluoroalkoxy resin (PFE, the multipolymer of tetrafluoroethylene and perfluorovinyl ether), the multipolymer (ETFE) of ethylene-tetrafluoroethylene, polychlorotrifluoroethylene (PCTFE), the multipolymer (ECTFE) of ethene-chloro-trifluoro-ethylene, poly(vinylidene fluoride) (PVDF), and fluorinated ethylene propylene (PVF) and its combination.In multiple embodiment, fluoropolymer nanoparticle comprises PTFE nanoparticle.

The median size of fluoropolymer nanoparticle is approximately preferably visible wavelength or is substantially less than visible wavelength (that is, being less than 380nm to 780nm).This median size can be less than about 500nm, is less than about 250nm, is less than about 200nm, is less than about 150nm, or is less than about 100nm.This median size can be greater than 5nm, is greater than about 10nm, or is greater than about 50nm.Therefore, median size can be from about 5nm to about 500nm, from about 10nm to about 500nm, from about 10nm to about 200nm, or from about 50nm to about 150nm.In some embodiments, fluoropolymer nanoparticle has the median size from about 50nm to about 100nm.In other embodiments, fluoropolymer nanoparticle has the median size from about 10nm to about 50nm.

Above-mentioned median size refers to the arithmetical av of the diameter in one group of fluoropolymer nanoparticle.One group of fluoropolymer nanoparticle is containing vicissitudinous diameter.Therefore, particle size can be described according to size distribution in addition, that is, the particle of minimum volume percentage ratio has the diameter lower than certain limit.Therefore, in multiple embodiment, fluoropolymer nanoparticle at least about 50 volume % has the particle diameter being less than 200nm, particle at least about 70 volume % has the particle diameter being less than 200nm, particle at least about 80 volume % has the particle diameter being less than 200nm, or has at least about the particle of 90 volume % the particle diameter being less than 200nm.

In some embodiments, fluoropolymer nanoparticle at least about 30 volume % has the particle diameter being less than 100nm, particle at least about 40 volume % has the particle diameter being less than 100nm, particle at least about 50 volume % has the particle diameter being less than 100nm, or has at least about the particle of 60 volume % the particle diameter being less than 100nm.

In other embodiments, the particle diameter had at least about the fluoropolymer nanoparticle of 25 volume % is less than 90nm, the particle diameter had at least about the particle of 35 volume % is less than 90nm, the particle diameter had at least about the particle of 45 volume % is less than 90nm, or is less than 90nm at least about the particle diameter that the particle of 55 volume % has.

In other embodiments, fluoropolymer nanoparticle at least about 20 volume % has the particle diameter being less than 80nm, particle at least about 30 volume % has the particle diameter being less than 80nm, particle at least about 40 volume % has the particle diameter being less than 80nm, or has at least about the particle of 50 volume % the particle diameter being less than 80nm.

In other embodiments, fluoropolymer nanoparticle at least about 10 volume % has the particle diameter being less than 70nm, particle at least about 20 volume % has the particle diameter being less than 70nm, particle at least about 30 volume % has the particle diameter being less than 70nm, or has at least about the particle of 35 volume % the particle diameter being less than 70nm.

The fluoropolymer nanoparticle adopted in the present invention has so-called " specific surface area ", and it refers to the total surface area of per unit mass nanoparticle.Along with particle diameter reduces, the specific surface area of the particle of given quality increases.Therefore, higher specific surface area is provided as general plotting compared with small-particle.With same in following mode: the sponge with enough exposed surface area has the specific absorption of increase compared with the object with smooth exterior, particle is in order to realize the function that the relative reactivity of specific function is the surface-area of particle to a certain extent.

In multiple embodiment, the present invention adopts fluoropolymer nanoparticle, wherein at least about 50 % by weight, preferably have at least about 15m at least about the nanoparticle of 90 % by weight ²/ g is (such as, at about 15m ²/ g and 35m ²between/g) specific surface area.The specific surface area of fluoropolymer nanoparticle can up to about 50m ²/ g.Such as, the dispersed system (PTFE dispersed system) of DRYFILMWD-4560 has about 23m ²the specific surface area of/g.Nanoparticle adopted in these embodiments can have area and the volume ratio on higher surface.According to the atomicity in a particle, these nanoparticles have the surface atom of higher percentages.Such as, only there is the atom from the teeth outwards compared with small-particle with this particle of about 92% of 13 atoms.In contrast, the larger particles with 1415 total atom numbers only has the atom of this particle of 35% from the teeth outwards.High atomic percent on the surface of particle relates to high particle surface energy, and more affects performance and activity.

The nanoparticle of the area and volume ratio with high specific surface area and high surface is favourable, this is due to compared with larger particles, can be merged in compound coating compared with the fluoropolymer particles of small proportion, then need more particle to realize identical surface-area, and also realize the effect of the frictional coefficient of erosion resistance and the reduction increased.Therefore, the fluoropolymer nanoparticle being low to moderate 10 % by weight in compound coating achieves required effect, and in some embodiments, fluoropolymer nanoparticle component is low to moderate 5 % by weight, such as, between about 1 % by weight and about 5 % by weight.

In electroplating composition, fluoropolymer nanoparticle typically with at least about 1g/L, exists at least about 2g/L or at least about the concentration of 5g/L.In multiple embodiment, fluoropolymer nanoparticle (such as, PTFE) concentration is at about 1g/L with about between 400g/L, at about 1g/L with about between 200g/L, at about 1g/L with about between 50g/L, at about 1g/L with about between 40g/L, at about 1.5g/L with about between 400g/L, at about 2g/L with about between 200g/L, at about 2g/L with about between 100g/L, at about 2.5g/L with about between 50g/L, at about 2g/L with about between 5g/L, at about 5g/L with about between 200g/L, at about 5g/L with about between 100g/L, at about 5g/L with about between 50g/L, at about 10g/L with about between 110g/L, or at about 10g/L with about between 50g/L.

If nanoparticle sources is TEFLONPTFE30, such as, the concentration in electroplating composition can by be added in the electroplating composition of every 1L about 1.5g and about between 350g, at about 5g with about realize between 170g or at the PTFE dispersed system of about 10g and 60 about between 100g % by weight.If nanoparticle sources be containing have an appointment 50 % by weight the dispersed system of PTFE, such as, DRYFILMWD-4560 (48 % by weight), then the concentration in electroplating composition can be low to moderate about 1g/L to realize by adding.In multiple embodiment, PTFE concentration in electroplating composition is at about 1g/L with about between 400g/L, at about 1.5g/L with about between 400g/L, at about 2g/L with about between 200g/L, at about 5g/L with about between 200g/L, at about 5g/L with about between 100g/L, at about 5g/L with about between 50g/L, at about 10g/L with about between 110g/L, or at about 10g/L with about between 50g/L.Calculate according to volume, the concentration in electroplating composition can by the electroplating composition of every 1L to add PTFE dispersion liquid at the volume of about 0.5mL and the PTFE dispersion liquid about between 160mL, more preferably to realize to add PTFE dispersion liquid at the volume of about 6mL and the PTFE dispersion liquid about between 80mL in the electroplating composition of every 1L.

The high surfactivity of fluoropolymer nanoparticle presents some significant challenge, such as, maintain uniform dispersed system.Therefore, fluoropolymer nanoparticle is dispersed in the solvent systems suppressing to reunite.For the solvent water typically of electroplating composition.When dispersed in water, hydrophobic fluoropolymer nanoparticle is easy to be agglomerated into the agglomerate having median size respectively and be greater than the median size of nanoparticle.Because the outward appearance of the nanoparticle negative impact money base compound coating of larger reunion and function, so this is disadvantageous.In other words, if smooth and do not have the money base compound coating of nanoparticle to contain the reunion block of nanoparticle, then it can be matte.In addition, the coacervate of large nanoparticle causes codeposition rate higher in compound coating.The higher deposition of idioelectric fluoropolymer particles can negative impact contact resistance.Therefore, for disperseing the solvent systems of fluoropolymer nanoparticle to comprise tensio-active agent, in order to suppress nanoparticle reunion in aqueous.

Usually, fluoropolymer nanoparticle is added to electroplating composition as with surfactant-stabilized dispersed system.In other words, fluoropolymer nanoparticle was stabilized in dispersed system by tensio-active agent before other components (that is, metal-salt, complexing agent, water etc.) with electroplating composition mix.

The dispersed system of fluoropolymer nanoparticle is commercially.An example of the dispersed system of fluoropolymer nanoparticle is TEFLONPTFE30 (can buy from DuPont company), and it is the dispersed system of the PTFE nanoparticle being approximately equal to or less than visible wavelength.PTFE30 comprises with the dispersed system of PTFE nanoparticle in water of the concentration of about 60 % by weight (every 100 grams of solution are containing 60 grams of particles), and wherein, particle has in about 50nm and the size distribution about between 500nm, and the median size of about 220nm.Another example of the dispersed system of fluoropolymer nanoparticle comprises DRYFILMWD-4560 (can buy from DuPont company), it is with the dispersed system of the PTFE nanoparticle of the concentration of about 48 % by weight in water, wherein, particle has the median size of about 80nm.These particles are typically dispersed in be had in the water/alcohol solvent system of tensio-active agent.Usually, alcohol is water-soluble alcohol, and it has 1 to about 4 carbon atom, such as, and methyl alcohol, ethanol, n-propyl alcohol, Virahol, propyl carbinol, isopropylcarbinol and the trimethyl carbinol.Typically, the ratio of water and alcohol (mole: mole) is between the alcohol of each mole of water of about 10 moles and the alcohol of each mole of water of about 20 moles, more typically between the alcohol of each mole of water of about 14 moles and the alcohol of each mole of water of about 18 moles.

Alternatively, the dispersed system to be added to the fluoropolymer nanoparticle of electroplating composition of the present invention can be prepared by the fluoropolymer particles of combination drying, solvent and tensio-active agent.The PTFE sources of particles of exemplary drying is TEFLONTE-5069AN, and it comprises and has the PTFE particle that median size is about the drying of 80nm.Other PTFE sources of particles comprises the ALGOFLON series product from Solvay company, and from the DYNEON series product that 3M company (St.Paul, Minnesota (U.S.)) can buy.

As indicated, the solvent systems for dispersing nanoparticles comprises one or more tensio-active agents, in order to suppress nanoparticle reunion in aqueous and to maintain the stable of dispersed system.Tensio-active agent can be cationic, negatively charged ion, non-ionic or zwitterionic.Special tensio-active agent can be used alone or combines with other tensio-active agents and uses.

Usually, tensio-active agent comprises hydrophilic head base and hydrophobic tail end.The hydrophilic head base associated with anion surfactant comprises carboxylicesters, sulphonate, sulfuric ester, phosphoric acid ester and phosphonic acid ester.The hydrophilic head base associated with cats product comprise quaternary amine base, sulfonium base and season phosphino-.Quaternary amine base comprises quaternary ammonium, pyridine, dipyridyl and imidazoles.The hydrophilic head base associated with nonionogenic tenside comprises alcohol and acid amides.The hydrophilic head base associated with zwitterionics comprises trimethyl-glycine.Hydrophobic tails typically comprises hydrocarbon chain.Hydrocarbon chain is typically included between about 6 carbon atoms and about 24 carbon atoms, more typically between about 8 carbon atoms and about 16 carbon atoms.

In multiple embodiment, the dispersed system of fluoropolymer nanoparticle comprises nonionogenic tenside.One class nonionogenic tenside comprises those tensio-active agents had based on the such as polyether group of the repeating unit of ethylene oxide (EO) and propylene oxide (PO).The tensio-active agent with polyether chain can be included in the EO repeating unit between about 1 and about 36, the PO repeating unit between about 1 and about 36, or the combination of EO repeating unit between about 1 and about 36 and PO repeating unit.More typically, polyether chain is included in the EO repeating unit between about 2 and about 24, the PO repeating unit between about 2 and about 24, or the combination of EO repeating unit between about 2 and about 24 and PO repeating unit.More typically, polyether chain is included in the EO repeating unit between about 6 and about 15, the PO repeating unit between about 6 and about 15, or the combination of EO repeating unit between about 6 and about 15 and PO repeating unit.These tensio-active agents can comprise the block of EO repeating unit and PO repeating unit, such as, and an EO repeat unit block of being surrounded by two PO repeat unit block or a PO repeat unit block of being surrounded by two EO repeat unit block.Another kind of polyethet surfactant comprises PO repeating unit alternately and EO repeating unit.Be polyoxyethylene glycol, polypropylene glycol and polypropylene glycol/polyoxyethylene glycol in the tensio-active agent of these kinds.

Another kind of nonionogenic tenside comprises the EO built on alcohol and phenolic group, PO, or EO/PO repeating unit, such as, glyceryl ether, butanols ether, amylalcohol ether, hexanol ether, enanthol ether, octanol ether, nonyl alcohol ether, decyl alcohol ether, dodecane alcohol ether, tetradecane alcohol ether, phenol ether, alkyl replace phenol ether, naphthyl alcohol ether and 2-Naphthol ether.About the phenol ether that alkyl replaces, phenolic group is replaced by the hydrocarbon chain with carbon atom between about 1 and about 10, and such as, the hydrocarbon chain of about 8 carbon atoms replaces hydrocarbon chain replacement (phenol in the ninth of the ten Heavenly Stems) of (octyl phenol) or about 9 carbon atoms.Polyether chain can be included in the EO repeating unit between about 1 and about 24, the PO repeating unit between about 1 and about 24, or the combination of EO repeating unit between about 1 and about 24 and PO repeating unit.More typically, polyether chain is included in the EO repeating unit between about 8 and about 16, the PO repeating unit between about 8 and about 16, or the combination of EO repeating unit between about 8 and about 16 and PO repeating unit.Even more typically, polyether chain comprises about 9, about 10, about 11, or about 12 EO repeating units; About 9, about 10, about 11, or about 12 PO repeating units; Or about 9, about 10, about 11, or the combination of about 12 EO repeating units and PO repeating unit.

The nonionogenic tenside of exemplary beta-naphthol derivative is LUGALVANBN012, and it is the 2-Naphthol ethoxylate with 12 the ethylene oxide monomeric units being bonded to naphthols hydroxyl.Similar tensio-active agent is POLYMAXNPA-15, and it is the phenol in the ninth of the ten Heavenly Stems of polyethoxylated.Another tensio-active agent is TRITON-X100 nonionogenic tenside, and it is octyl phenol ethoxylate, typically has about 9 or 10 EO repeating units.The nonionogenic tenside can bought from market in addition comprises PLURONICP, L, and the tensio-active agent of F series.PLURONIC tensio-active agent comprises the Pluronic PE 6800 of P series, comprises P65, P84, P85, P103, P104, P105, and P123; The Pluronic PE 6800 of F series, comprises F108, F127, F38, F68, F77, F87, F88, F98; Pluronic PE 6800 with L series, comprises L10, L101, L121, L31, L35, L44, L61, L62, L64, L81, and L92.These tensio-active agents can be bought from BASF AG.

The nonionogenic tenside can bought from market in addition comprises water miscible, the nonionic fluorosurfactant of ethoxylation, it can be bought from DuPont company and sell with trade name ZONYL, comprises ZONYLFSN (having the nonionogenic tenside of the telomarB monoether of polyoxyethylene glycol), ZONYLFSN-100, ZONYLFS-300, ZONYLFS-500, ZONYLFS-510, ZONYLFS-610, ZONYLFSP, and ZONYLUR.Other nonionogenic tensides comprise amine condenses, such as cocamidopropyl DEA and cocamidopropyl MEA.The nonionogenic tenside of other kinds comprises the lipid acid (polyethoxye ester) of sour ethoxylation, and it comprises the lipid acid with polyether-based esterification, and typically, this polyether-based is included in the EO repeating unit between about 1 and about 36.Glyceryl ester is included in one, two or three fatty acid groups on glyceryl.

In multiple embodiment, the dispersed system of fluoropolymer nanoparticle comprises anion surfactant.Exemplary anionic surfactants comprises phosphonate ester, alkyl ether phosphate, alkyl sulfuric ester, alkyl ether sulphate, alkyl sulfonic ester, alkyl ether sulfonates, ether carboxylic acid, carboxylicesters, alkyl aryl sulfonate and sulfosuccinic ester.Anion surfactant comprises any one sulfuric ester, such as, with the sulfuric ester (can buy from MFGChemical company) that trade name ULTRAFAX sells, comprise sodium laurylsulfate, sodium laureth sulfate (2 EO), sodium laureth sulfate, sodium laureth sulfate (3 EO), lauryl sulfate, lauryl alcohol ammonium sulfate, TEA-lauryl alcohol sulfuric ester, TEA-lauryl alcohol sulfuric ester, MEA-lauryl alcohol sulfuric ester, MEA-lauryl alcohol sulfuric ester, lauryl alcohol potassium sulfate, lauryl alcohol potassium sulfate, sodium decyl sulfate, octyl group/sodium decyl sulfate, sodium 2-ethylhexyl sulfate, sodium octyl sulfate, nonoxynolum-4 sodium sulfate, nonoxynolum-6 sodium sulfate, sodium cumene sulfate, with nonoxynolum-6 ammonium sulfate.Anion surfactant also comprises sulphonate, such as alpha-olefin sodium sulfonate, xylene monosulfonic acid amine, sodium xylene sulfonate, toluenesulfonic acid sodium salt, dodecylbenzene sulfonate and Sulfite lignin.Other anion surfactant comprises sulfosuccinate surfactant, such as lauryl alcohol disodium sulfosuccinate, laureth disodium sulfosuccinate; Comprise with other anion surfactants; cocoyl-2-ethanol sodium sulfonate; lauryl alcohol phosphoric acid ester; the phosphonic acid ester (can buy from MFGChemicalInc company) of arbitrary ULTRAPHOS series; CYASTAT609 (N; two (2-hydroxyethyl)-N-(3 '-dodecyloxy-2 '-hydroxypropyl) the methylamine methylsulfuric acid ester of N-) and CYASTATLS (3-lauroyl aminocarbonyl propyl) Trimethylamine methylsulfuric acid ester), it can be bought from CytecIndustries company.

In multiple embodiment, the dispersed system of fluoropolymer particles comprises cats product.Exemplary cationic tensio-active agent comprises quaternary ammonium salt, such as Dodecyl trimethyl ammonium chloride, bromide and muriatic cetyltrimethyl ammonium salt, bromide and muriatic cetyltrimethyl ammonium salt, bromide and muriatic alkyl dimethyl benzyl ammonium salt etc.In this aspect, S-106A (the fluoroalkyl salmiac cation tensio-active agent of 28% to 30% and S-208M (negatively charged ion of the mixing of 33% and cationic fluoroalkyl surfactants that tensio-active agent such as can be bought from ChemguardSpecialtyChemicals & Equipment, there is clean positive charge), with AMMONYX4002 (stearyl dimethyl benzyl ammonium chloride cats product, can buy from Stepan company (Northfield, Ill)) be applicable.

According to the present invention, electroplating composition comprises cosurfactant.During the mixing of the fluoropolymer nanoparticle dispersion system in electroplating composition, the tensio-active agent of the pre-mixing existed in dispersed system, by electroplating composition solution dilution, makes fluoropolymer nanoparticle can be unstable and reunite.The stability making the cosurfactant of significant quantity be incorporated to electroplating composition to be found by preventing the reunion of particle from maintaining fluoropolymer nanoparticle dispersion system.Cosurfactant can also promote the wetting of substrate surface and change the surface tension of electroplate liquid.Typically, cosurfactant comprises nonionogenic tenside or cats product.Cosurfactant can be any nonionogenic tenside or cats product of being suitable for being incorporated to fluoropolymer nanoparticle dispersion system as previously mentioned.

As mentioned before, fluoropolymer nanoparticle with silver or silver alloy codeposition on the surface of a substrate.Nanoparticle is not reduced, but is trapped in cathode surface interface by silver ions or silver alloys ion, and this silver ions or silver alloys ion are reduced and are deposited on around fluoropolymer nanoparticle-surfactant complex.Cosurfactant can be selected to make most of positive charge to be imparted to nanoparticle, and then this is convenient to nanoparticle easily makes them adhere to surface until encapsulated by metal refining and be trapped on the surface towards cathodic migration.

In multiple embodiment, cosurfactant comprises the cats product whole positive tensio-active agent electric charges being imparted to fluoropolymer nanoparticle.Compared with other uncharged complexing agents, positively charged fluoropolymer nanoparticle-surfactant complex will be easy to during galvanic deposit, drive particle towards cathode substrate to a greater degree.

The total charge of fluoropolymer nanoparticle-surfactant complex can be quantized as follows.The electric charge of specific surfactant molecule typically is-1 (negatively charged ion), 0 (non-ionic or zwitter-ion), or+1 (positively charged ion).Therefore one group of surfactant molecule has the mean charge of each surfactant molecule between-1 (whole group comprises anionic surfactant molecules) and+1 (whole group comprises cats product molecule).One group of surfactant molecule with 0 electric charge generally can comprise, such as, the anionic surfactant molecules of 50% and the cats product molecule of 50%, the zwitterionics molecule of 100%, or 100% nonionogenic tenside molecule.

When mixing fluoropolymer nanoparticle dispersion system and cosurfactant in electroplating composition, electroplating composition comprises the combination of positively charged ion, negatively charged ion and/or nonionogenic tenside molecule and other negatively charged ion, zwitter-ion, positively charged ion and/or nonionogenic tenside molecule.Preferably, the mean charge of each surfactant molecule of the surfactant molecule group in complex compound is greater than 0.In some embodiments, electroplating composition comprises the positively charged ion cosurfactant used with the nonionic surfactant combinations of the cats product of one or more pre-mixings and/or one or more pre-mixings.Therefore, in multiple embodiment, surfactant mixture comprises cats product molecule and nonionogenic tenside molecule, and it preferably to have between about 0.01 (the nonionogenic tenside molecule of 99% and the cats product molecule of 1%) and 1 (the cats product molecule of 100%) or at the mean charge of about 0.1 (the nonionogenic tenside molecule of 90% and the cats product molecule of 10%) and each surfactant molecule between 1.The mean charge being formed in each surfactant molecule of the surfactant molecule group of the surfactant mixture (tensio-active agent+cosurfactant of pre-mixing) in electroplating composition can be at least about 0.2 (the nonionogenic tenside molecule of 80% and the cats product molecule of 20%), such as, at least about 0.3 (the nonionogenic tenside molecule of 70% and the cats product molecule of 30%), at least about 0.4 the cats product molecule of 40% (the 60% nonionogenic tenside molecule and), at least about 0.5 (the nonionogenic tenside molecule of 50% and the cats product molecule of 50%), at least about 0.6 (the nonionogenic tenside molecule of 40% and the cats product molecule of 60%), at least about 0.7 (the nonionogenic tenside molecule of 30% and the cats product molecule of 70%), at least about 0.8 (the nonionogenic tenside molecule of 20% and the cats product molecule of 80%), or even at least about 0.9 (the nonionogenic tenside molecule of 10% and the cats product molecule of 90%).In each embodiment in these embodiments, the mean charge of each surfactant molecule is for being not more than 1.

The concentration of cosurfactant can be measured by total granulate-matrix interfacial area.For the weight concentration of given particle, median size is less, and the total area of particle surface is higher.By the long-pending (m of specific grain surface ²/ g) be multiplied by particle weight (g) in solution, calculate total surface area.Calculating creates with m ²the total surface area represented.With the Particle Phase ratio of the micron-scale of identical weight concentration, the fluoropolymer nanoparticle having high specific grain surface long-pending of given concentration comprises more total number of particles.Therefore, the tensio-active agent of high density be used for reduce nanoparticle flocculation or cohesion trend.Therefore cosurfactant concentration be the quality of particle and the function of specific surface area.Therefore, in multiple embodiment, for each about 10m ²to about 450m ², about 10m ²to about 250m ², about 20m ²to about 150m ², about 20m ²to about 150m ², about 20m ²to about 80m ², or about 30m ²to about 75m ²the fluoropolymer particles of surface-area, composition comprises the cosurfactant of about a gram.

Such as, DRYFILMWD-4560 is the PTFE nanoparticle dispersion system that can buy from DuPont company, and it is containing the median size with about 80nm of 48 % by weight and the about 23.0m of having an appointment ²the PTFE particle of the specific surface area of/g.From about 0.05g to about 2g in order to maintain the quality of the cosurfactant of the dispersed system of one gram of these PTFE particle, from about 0.1g to about 2g, from about 0.2g to about 1.5g, or from about 0.3g to about 1g (such as about 0.3g).

Cosurfactant concentration can also be designated as the fluoropolymer particles surface-area of molar basis per unit.Cosurfactant volumetric molar concentration can scope be from least about 0.0001 mmole to the fluoropolymer particles surface-area of every square metre, the tensio-active agent of about 1 mmole.In multiple embodiment, cosurfactant volumetric molar concentration is from about 0.0005 mmole to about 0.5 mmole, from about 0.001 mmole to about 0.5 mmole, or from about 0.005 mmole to the fluoropolymer particles surface-area of every square metre, the tensio-active agent of about 0.1 mmole.In some embodiments, cosurfactant volumetric molar concentration is from about 0.0125 mmole to about 1 mmole, from about 0.015 mmole to about 0.5 mmole, from about 0.05 mmole to about 0.25 mmole, from about 0.075 mmole to about 0.15 mmole, or from about 0.02 mmole to the fluoropolymer particles surface-area of every square metre, the tensio-active agent of about 0.1 mmole.In other embodiments, cosurfactant volumetric molar concentration is to about 0.002 mmole or from about 0.0005 mmole to the fluoropolymer particles surface-area of every square metre, the tensio-active agent of about 0.002 mmole from about 0.0001 mmole.

In some embodiments, cosurfactant comprises cationic fluorosurfactants promoting agent.Make the cationic fluorosurfactants promoting agent of significant quantity be incorporated to electroplating composition to be found not only to make fluoropolymer dispersed system stablize, and provide the stability on the period (such as, being greater than one month) extended.In addition, surprisingly, cationic fluorosurfactants promoting agent provide when compared with other surfactant fluoropolymer particles and silver larger codeposition degree and by having highlighted and the sedimental outward appearance of color perfecting.In some embodiments, cosurfactant comprises cationic fluorosurfactants promoting agent, wherein electroplating composition does not contain any nonionic fluorosurfactant or is substantially devoid of any nonionic fluorosurfactant (that is, being not more than the fluoropolymer particles surface-area of the nonionic fluorosurfactant every square metre of about 0.00005 mmole or about 0.00001 mmole).In some embodiments, cosurfactant comprises or mainly comprises the mixture of cationic fluorosurfactants promoting agent or anionic fluorosurfactants and cationic fluorosurfactants promoting agent.In other embodiments, the unique fluorochemical surfactant contained in electroplating composition is cationic fluorosurfactants promoting agent.In some embodiments, other cats products (that is, being not more than the fluoropolymer particles surface-area of the nonionic fluorosurfactant every square metre of about 0.00005 mmole or about 0.00001 mmole) that electroplating composition does not contain other cats products outside cationic fluorosurfactants promoting agent or is substantially devoid of outside cationic fluorosurfactants promoting agent.

Fluorochemical surfactant comprises, such as, and the fluoroalkyl ammonium salt of halogenide (such as, bromide and muriate).Specific fluorochemical surfactant is S-106A (the fluoroalkyl salmiac cation tensio-active agent of 28% to 30% and the hexylene glycol of 10%) and S-208M (negatively charged ion of the mixing of 33% and cation fluorine alkyl surfactants, there is clean positive charge), it can be bought from ChemguardSpecialtyChemicals & Equipment company.In some embodiments, cosurfactant comprises or mainly comprises fluoroalkyl salmiac cation tensio-active agent.

Have been found that making the cationic fluorosurfactants promoting agent of higher rate be incorporated into fluoropolymer nanoparticle surface amasss and provide larger stability to electroplating composition.Therefore, in some embodiments, for each about 10m ²to about 80m ², about 20m ²to about 80m ², about 30m ²to about 75m ², or about 50m ²to about 70m ²the fluoropolymer particles of surface-area, composition comprises the cationic fluorosurfactants promoting agent of about a gram.In some embodiments, the concentration of the cationic fluorosurfactants promoting agent in electroplating composition is from about 0.2g/L to about 35g/L, from about 0.5g/L to about 20g/L, from about 0.5g/L to about 10g/L, from about 1g/L to about 6g/L, from about 1g/L to about 5g/L, from about 1g/L to about 4g/L, from about 1g/L to about 3g/L, or from about 1.5g/L to about 6g/L.

Electroplating composition of the present invention can comprise other additives, and it comprises such as, wetting agent, conducting salt, brightening agent, complexing agent, pH adjusting agent, and buffer reagent.

In multiple embodiment, electroplating composition of the present invention comprises wetting agent.Wetting agent is added to electroplating composition to promote the wetting of substrate surface and the surface tension of change electroplate liquid.About electro-plating method, there is the electroplate liquid of low surface tension advantageously: (1) strengthens the wetting of substrate surface; (2) ability that solution reduces or eliminates bubble is strengthened; (3) concave surface/cavity on plate surface is prevented; (4) solvability of organic materials (such as, grain-refining agent, brightening agent and other solution additives) is increased; (5) reduce the deposition potential of various metals, this allows uniform settling and alloy.The electroplate liquid with low surface tension is particularly advantageous about fluoropolymer nanoparticle, this is because which enhance the dispersiveness of fluoropolymer nanoparticle in electroplating composition.

Suitable wetting agent used in the present invention comprises, such as, and sulfonic acid, the such as 2-Naphthol of sulfopropyl poly-alkoxylation, the condensed products of naphthene sulfonic acid, and its salt (such as, poly-naphthalene formaldehyde sulfonate).The particular example of wetting agent comprises the TAMOLN series (such as, TAMOLNN9401 and TAMOLNN8906) and VULTAMOLNN series that can buy from BASF.

Typically, electroplating composition contains at least about 5g/L, at least about 10g/L, at least about 15g/L, or at least about the wetting agent of 20g/L.In multiple embodiment, electroplating composition contains from about 5g/L to about 50g/L, from about 5 to about 40g/L, from about 10g/L to about 30g/L, or from about 10g/L to the wetting agent of about 20g/L.

Electroplating composition of the present invention can also comprise conducting salt, and this conducting salt comprises concentration between 50g/L and 500g/L, between 100g/L and 300g/L, or sulfonic acid between 130g/L and 200g/L and/or sulfonic acid.Preferably, conducting salt comprises methanesulfonic potassium.Except methanesulfonic potassium, other methane sulfonates (such as methanesulfonic sodium) is applicable, and vitriol and other compounds are also suitable as the conducting salt used in electroplating composition.

The alkali metal bromide of significant quantity can be added to electroplating composition, for improving deposition results (such as, according to concentration, from bright to unglazed).The interpolation of alkali metal bromide (especially Potassium Bromide) generally provide compound coating on the surface of a substrate evenly outward appearance.When the uniform dim layer of needs, Potassium Bromide is specially suitable.And, about color, by add alkali metal bromide (such as Potassium Bromide), obtain evenly deposition results.Therefore, in multiple embodiment, electroplating composition comprises from about 30mg/L to about 500mg/L or from about 100mg/L to the alkali metal bromide of about 200mg/L.Other additives (such as bismuth citrate and selenium salt) also can be added to improve surface brightness.

In some embodiments, electroplating composition comprises thiosulphate, such as, and Sulfothiorine.Thiosulphate is typically to be added to electroplating composition from about 50mg/L to about 500mg/L or from about 100mg/L to the concentration of about 200mg/L.Herein, thiosulphate serves as matting agent.The silver layer deposited by this electroplating composition is dim equably, there is internal stress hardly, and has excellent welding property.

In multiple embodiment, electroplating composition also comprises antifoam additive.Such as, can be used for controlling the amount of the foam generated between the usage period of electroplating composition based on the emulsion antifoam agent of silicone.The suitable antifoam additive based on silicone is a DC1430, and it can be bought from DowCorning company.When deployed, antifoam additive is typically to be added to electroplating composition from about 10ppm to about 500ppm or from about 30ppm to the amount of about 300ppm.

In some embodiments, electroplating composition of the present invention comprises following:

The concentration of each component can change independently in such as listed above specified range.

From about 8 to about 14 according to the pH value of electroplating composition of the present invention, from about 9 to about pH12.5, from about 9.5 to about 11.5, or from about 9 to about 11.The alkali of such as potassium hydroxide can be used for maintaining the pH value of composition.

Electroplating composition can be prepared by the following method.First, complexing agent (such as, hydantoin compound), any wetting agent and conducting salt (such as, methanesulfonic potassium) mix to form solution with water.Source of silver ions (such as, Ag-MSA) is added to solution, then adds cationic fluorosurfactants promoting agent and any alkali metal bromide.Then, the pre-mixing dispersed system comprising fluoropolymer nanoparticle particle and tensio-active agent is mixed together in the solution together with required any antifoam additive.In order to avoid precipitation, the pH value of solution is maintained from about 9 to about 11 (such as, about 10) during whole technique.The alkali of such as potassium hydroxide can be added the pH value maintaining solution as required.

Electroplating composition of the present invention is used in for making in the method for money base compound coating galvanic deposit on substrate.Contacted with electroplating composition by the surface of substrate, galvanic deposit occurs.Cathode substrate and anode are electrically connected to rectifier respectively by wire.That is, outside electron source is applied to electroplating composition to make compound coating galvanic deposit on substrate surface thus.Cathode substrate has clean negative charge and metal ions is in the solution reduced make money base compound coating be deposited on cathode substrate place on cathode surface.Oxidizing reaction occurs in anode place.Nanoparticle is trapped in interface by metal ion, and this metal ion is reduced and is deposited on around nanoparticle.Negative electrode and anode can flatly or be vertically arranged in groove.

Between the working life of electroplating system, when rectifier is energized, metal ions is reduced on the surface of cathode substrate.Pulsed current, galvanic current, reversal periods electric current, or other suitable electric currents can be utilized.Typically, from about 0.1A/dm ²to about 10A/dm ², from about 1A/dm ²to about 5A/dm ², or from about 2.5A/dm ²to about 3.5A/dm ²setting current density under, substrate to be coated contacts with electroplating composition.From about 0.05 μm/min to about 5 μm/min, from about 0.5 μm/min to about 5 μm/min, from about 1 μm/min to about 5 μm/min, or plating speed from about 1 μm/min to about 2.5 μm/min, can depositing silver base composite coating.

Utilize heater/cooler, can maintain the temperature of electrolytic solution, electrolytic solution flows out and flows through heater/cooler from stock chest thus, is then circulated to stock chest.The typical operating temperature scope of electrolyte composition from about 40 DEG C to about 60 DEG C, from about 40 DEG C to about 55 DEG C, or from about 50 DEG C to about 55 DEG C.

Money base compound coating of the present invention can be applied to multiple substrate.Electrical connector and other electronic units are comprised according to the illustrative substrate of money base compound coating of the present invention, automobile component, metallized plastics, and the inviscid parts for using in injection molding tool for being coated with.In some embodiments, comprise electrical connector for the substrate applied, and more particularly, there is or do not have copper or the copper alloy web member on nickel blocking layer.

The money base compound coating comprising fluoropolymer nanoparticle utilizing electroplating composition of the present invention to deposit can have and is not more than about 20 μm, is not more than about 10 μm, is not more than about 5 μm, or be not more than the thickness of about 3 μm.Such as, in some embodiments, the thickness of money base compound coating is from about 0.5 μm to about 10 μm, from about 1 μm to about 10 μm, or from about μm to about 5 μm (such as, about 1 μm to about 3 μm).

When compared with the silver coating prepared by the similar electroplating composition not containing fluoropolymer nanoparticle, the money base compound coating comprising fluoropolymer nanoparticle utilizing electroplating composition of the present invention to deposit has the frictional coefficient obviously reduced.Therefore, in multiple embodiment, money base compound coating has from about 0.05 to about 0.5, and from about 0.05 to about 0.3, or from the frictional coefficient of about 0.1 to about 0.2.

The money base compound coating comprising fluoropolymer nanoparticle utilizing electroplating composition of the present invention to deposit is typically containing at least 1.2 % by weight, 1.5 % by weight, 1.8 % by weight, 2.0 % by weight, 2.5 % by weight, the fluorine (atom) of 3.0 % by weight, 3.5 % by weight or 4.0 % by weight, it can be composed (EDS) to measure by Energy Dispersive X-ray.In specific embodiment, money base compound coating contains from about 1 % by weight to about 7 % by weight, from about 1 % by weight to about 5 % by weight, from about 1 % by weight to about 3 % by weight, from about 2 % by weight to about 7 % by weight, from about 2.5 % by weight to about 5 % by weight, or from about 3 % by weight to about 4 % by weight fluorine (atom).

Electroplating composition of the present invention provides a kind of money base compound coating with the contact resistance suitable with the silver based coatings not containing fluoropolymer nanoparticle.Therefore, money base compound coating typically has and is less than about 10 milliohms, is less than about 5 milliohms, or is less than the contact resistance of about 2 milliohms.In addition, different from fine silver settling, even if the contact resistance comprising the money base compound coating of fluoropolymer nanoparticle utilizing electroplating composition of the present invention to deposit remains constant or almost constant after thermal aging and there is not nickel blocking layer.Such as, under the static load between 50 grams and 250 grams, keep after 100 hours at 150 DEG C, money base compound coating has and is less than about 10 milliohms, is less than about 5 milliohms, or is less than the contact resistance of about 2 milliohms.

Even if electroplating composition of the present invention provides the money base compound coating also maintaining uniform outer appearance after thermal aging.Fine silver settling on copper or copper alloy substrate fades because copper is diffused into the surface of deposition of silver thing.But, money base compound coating of the present invention restriction or eliminate copper diffusion and make sedimental outward appearance in time and be exposed to heat and still remain even.

After having described the present invention in detail, apparently, amendment and modification are possible and do not depart from scope of the present invention limited in the appended claims.

Embodiment

Provide following non-limiting example to explain the present invention further.

Embodiment 1

Following electroplating composition is produced the deposition for silver and money base compound coating.The pH value of each composition is approximately 9.5.Add potassium hydroxide as required to maintain this pH value.

Copper alloy substrate is at 2.6A/dm ²about 1 minute is contacted with each plating solution under the current density of the setting of (1.2 μ/min).The frictional coefficient (COF) of each coating utilizing CETR general micro tribology measurement amount to be deposited by these electroplating bath solutions and contact resistance (CR).The load of 50g is applied in 500 circulations to measure frictional coefficient.During measuring contact resistance, use the ball of pure silver lustre plating.The weight percent of atomic fluorine is in the coating measured by EDS.Present these measuring results in the following table.

After PVvalue testing, be also evaluated wear resistance (it applies the load of 50g in the process of 500 circulations of sliding) by the coatingsurface had prepared by the plating solution 1-3 of PTFE nanoparticle and plating solution 1-4.Profilograph is utilized to measure the profile on each surface.The skeleton diagram on each surface provides respectively in Figure 1A and Figure 1B.The width of the wear print on the silver coating prepared by plating solution 1-3 is 290 microns, the degree of depth about 1.8 microns.Width for the wear print of the silver-colored compound coating prepared by the plating solution 1-4 with PTFE nanoparticle is 186 microns, the degree of depth about 0.4 micron.

Result from these tests shows, composition of the present invention significantly reduces the frictional coefficient of silver coating and improves wear resistance, maintains low contact resistance simultaneously.

Embodiment 2

Utilize the plating solution 1-4 prepared by embodiment 1, silver-colored compound coating is deposited on copper alloy substrate.Coated substrate then at 125 DEG C by heating seven days.After thermal aging, frictional coefficient as described in Example 1 and measuring contact resistance is repeated.Result shows, after thermal aging, these performances are constant.

Embodiment 3

The solution of utilized as silver methane sulfonate mixes with the PTFE dispersed system under the concentration of the PTFE of 10g/L.The tensio-active agent that the sample of solution is different from four kinds mixes.After shelf aging five weeks, detect the stability of solution.Result provides in the following table.

Embodiment 4

Utilize the composition prepared by embodiment 3, copper alloy substrate is coated with silver-colored compound coating.After during the shelf aging of electroplating composition, substrate is coated.The weight percent (w%F) of atomic fluorine measures the observed value as PTFE nanoparticle codeposition speed by EDS.Present the figure of digestion time to w%F in fig. 2.During the whole burn-in test cycle, fluorochemical surfactant S106A provides the highest PTFE nanoparticle codeposition speed.

Embodiment 5

Utilize plating solution 1-4 prepared by embodiment 1, a series of copper alloy substrate is coated with silver-colored compound coating, except the concentration of PTFE nanoparticle changes from 0g/L to 40g/L.After coating (newly formed) and after thermal ageing test, the outward appearance of observation coating: after (1) heats 168 hours at 125 DEG C, or after (2) heat 100 hours at 150 DEG C.Fig. 3 illustrates the image on the surface of each substrate after each period.Fine silver coating and the compound coating display deposited by the electroplating composition of the PTFE nanoparticle containing 1g/L are faded, and this part is because copper is diffused into the surface of silver coating.Even if the substrate with the silver-colored compound coating deposited by the electroplating composition of the PTFE nanoparticle containing 5g/L or more also has uniform outward appearance after thermal ageing test.

Fig. 4 illustrates scanning electronic microscope (SEM) image on each surface after coating (newly formed).SEM image shows, PTFE particle distributes (in Fig. 4 to Fig. 9 in specific image, stain is PTFE particle) equably in whole coatingsurface.Fig. 5 provides the SEM image of the composite silver coating prepared by the plating solution containing 40g/lPTFE.Image shows, PTFE particle distributed in three dimensions equably in whole coating.Fig. 6 illustrates and to heat after 168 hours at 125 DEG C, the SEM image of coated surface grain structure.Fig. 7 illustrates and to heat after 100 hours at 150 DEG C, the SEM image of coated surface grain structure.Fig. 8 illustrates and to heat after 100 hours at 150 DEG C, focused ion beam (FIB) image of the cross section of selected sample.In fine silver settling, the space of hollow is identified along copper substrate surface and silver-colored interface, and it may diffuse through silver layer by copper and cause.Composite silver coating prepared by the plating solution containing 5g/lPTFE presents the interface of close-fitting substrate surface and silver-PTFE.Fig. 9 illustrates and to heat after 100 hours at 150 DEG C, the focused ion beam FIB image of the cross section of selected sample.The copper particle of diffusion is present on the surface of fine silver settling (0g/LPTFE), and it shows the spot of the light color for sedimental near surface.Composite silver coating prepared by the plating solution containing 10g/lPTFE seems effectively to prevent copper to be diffused into sedimental surface, and this presents the interface of close-fitting substrate surface and silver-PTFE.

The general micro tribology instrument of CETR and QUadTechLR2000 milliohmmeter is utilized to measure the contact resistance of each coating.Frictiograph controls the load applied, and it increases to 250g from 0g.During measuring contact resistance, use pure silver lustre plating ball.The measuring contact resistance value for each newly formed substrate (not having thermal ageing) is presented in Figure 10 A and table 1.Present the amplification selection figure between 1 milliohm and 2 milliohm contact resistances of Figure 10 A in fig. 1 ob.Present in Figure 10 C and table 2 and heat after 100 hours at 150 DEG C, for the measuring contact resistance value of each substrate.Present in Figure 10 D and table 3 and heat after 168 hours at 125 DEG C, for the measuring contact resistance value of each substrate.The amplification selection figure between 1 milliohm and 4 milliohm contact resistances of Figure 10 D is presented in Figure 10 E.

The measuring contact resistance value of the substrate (not having thermal ageing) that table 1. newly applies

Table 2. at 150 DEG C after 100 hours, the measuring contact resistance value of coated substrate

Table 3. at 125 DEG C after 168 hours, the measuring contact resistance value of coated substrate

Significantly, at 150 DEG C after thermal ageing 100 hours, the compound coating that fine silver coating and the electroplating composition by the PTFE nanoparticle only containing 1g/L deposit has the contact resistance higher than 10 milliohms respectively.Even if the contact resistance with the substrate of the silver-colored compound coating deposited by the electroplating composition of the PTFE nanoparticle containing 5g/L or more after thermal ageing test also all the time lower than 5 milliohms.

Embodiment 6

Utilize Auger electron spectrum (AES) analysis from the substrate of the compound coating having fine silver coating and deposited by the electroplating composition of the PTFE nanoparticle containing 10g/L of embodiment 5, it has stood the thermal ageing continuing 100 hours at 150 DEG C.Figure 11 A presents for fine silver coating, with this AES analytical results of the change of profile depth.Figure 11 B presents the compound coating deposited for the electroplating composition by the PTFE nanoparticle containing 10g/L, with this AES analytical results of the change of profile depth.Result shows, after thermal aging, fine silver coating contains a large amount of copper in the surface of deposition of silver thing.On the other hand, compound coating contains the copper of negligible quantity in surface.These results show, compound coating is effective in the surface of limit copper diffusion to silver coating.

Embodiment 7

Brass alloys substrate is plated for testing high speed electrodeposition purposes in flow-through cell.Three kinds of electroplating compositions are tested in this experiment.Cationic fluorosurfactants surfactant concentration is change (that is, 1.7ml/L, 2.5ml/L, or 3.3ml/L) in each electroplating composition.Electroplating composition contains following composition:

In each test run, flow-through cell container contains the electroplating composition of 8 liters.Sprinker is positioned at the bottom of flow-through cell container and the surface of sensing substrate.During use, electroplating composition is stirred.The pH value of each electroplating composition is maintained at about 10, and is maintained at about 53 DEG C in the temperature of electroplating.Each substrate is immersed in electroplating composition and continues 1 minute, moves horizontally in a reservoir to simulate high speed electrodeposition simultaneously.The current density applied is approximately 2.5A/dm ².Make the observed result of the foam levels of each electroplating composition used.Each composition has acceptable foam levels.

The thickness of the silver-colored compound coating on the front and back of substrate is measured by XRF technology.In addition, the observed value of weight percent (w%F) as PTFE nanoparticle codeposition speed of atomic fluorine is measured by EDS.Result is provided in following table 4.

The thickness of table 4. coated substrate and atomic fluorine measuring result

Compare the outward appearance of each substrate.The image of coated substrate is presented in Figure 12.Coating is uniform, but the coating color deposited by the electroplating composition of the tensio-active agent containing 1.7ml/L is faint yellow.Make surfactant concentration increase to 2.5ml/L and 3.3ml/L and improve sedimental color.In addition, this embodiment illustrates that electroplating composition is suitable for high speed electrodeposition purposes.

When introducing the element of the present invention or its preferred implementation, article " " (" a ", " an ") and " described " (" the " and " said ") refer to there is one or more element.Term " comprises ", " comprising " and " having " refer to comprising property and refer to the other element that can exist and enumerate outside element.

According to above, can find out, achieve multiple object of the present invention and obtain other advantageous resultss.

Do not depart from the scope of the present invention due to multiple change can be made in above-mentioned composition and method, therefore to be intended that in above-mentioned specification sheets and accompanying drawing contained all the elements and should to be understood as that illustrative but not restrictive sense.

Claims (52)

1., for making the silver of compound or silver alloys be coated with the electroplating composition be deposited upon on substrate, described electroplating composition comprises:

A () comprises the source of silver ions of utilized as silver methane sulfonate (Ag-MSA);

B () comprises the complexing agent with nitrogenous heterocyclic compound;

C () comprises the pre-mixing dispersed system of fluoropolymer nanoparticle particle and tensio-active agent, described fluoropolymer nanoparticle particle has the median size from about 10nm to about 500nm; With

D () comprises the cosurfactant of cationic fluorosurfactants promoting agent, wherein, described composition has the pH value from about 8 to about 14.

2. electroplating composition as claimed in claim 1, wherein, described cosurfactant also comprises anionic fluorosurfactants.

3. electroplating composition as claimed in claim 1 or 2, wherein, described electroplating composition is substantially devoid of any nonionic fluorosurfactant.

4. electroplating composition as claimed in claim 3, wherein, described electroplating composition is not containing any nonionic fluorosurfactant.

5. the electroplating composition according to any one of Claims 1-4, wherein, described cationic fluorosurfactants promoting agent comprises fluoroalkyl ammonium halide tensio-active agent.

6. the electroplating composition according to any one of claim 1 to 5, wherein, described fluoropolymer nanoparticle has at about 15m ²/ g and about 50m ²between/g or at about 20m ²/ g and about 50m ²specific surface area between/g.

7. the electroplating composition according to any one of claim 1 to 6, wherein, the concentration of described cationic fluorosurfactants promoting agent is from about 0.2g/L to about 35g/L, from about 0.5g/L to about 20g/L, from about 0.5g/L to about 10g/L, from about 1g/L to about 6g/L, from about 1g/L to about 5g/L, from about 1g/L to about 4g/L, from about 1g/L to about 3g/L or from about 1.5g/L to about 6g/L.

8. the electroplating composition according to any one of claim 1 to 6, wherein, for each about 10m ²to about 80m ², about 20m ²to about 80m ², about 30m ²to about 75m ², or about 50m ²to about 70m ²the fluoropolymer particles of surface-area, described electroplating composition comprises the cationic fluorosurfactants promoting agent of about a gram.

9. the electroplating composition according to any one of claim 1 to 6, wherein, the concentration of described cationic fluorosurfactants promoting agent is from about 0.0005 mmole to about 0.5 mmole, from about 0.001 mmole to about 0.5 mmole or from about 0.005 mmole to the fluoropolymer particles surface-area of every square metre, the tensio-active agent of about 0.1 mmole.

10. the electroplating composition according to any one of claim 1 to 6, wherein, the concentration of described cationic fluorosurfactants promoting agent is from about 0.0125 mmole to about 1 mmole, from about 0.015 mmole to about 0.5 mmole, from about 0.05 mmole to about 0.25 mmole, from about 0.075 mmole to about 0.15 mmole or from about 0.02 mmole to the fluoropolymer particles surface-area of every square metre, the tensio-active agent of about 0.1 mmole.

11. electroplating compositions according to any one of claim 1 to 6, wherein, the concentration of described cationic fluorosurfactants promoting agent is to every square metre, the tensio-active agent fluoropolymer particles surface-area of about 0.002 mmole or from about 0.0005 mmole to every square metre, the tensio-active agent fluoropolymer particles surface-area of about 0.002 mmole from about 0.0001 mmole.

12. electroplating compositions according to any one of claim 1 to 6, wherein, the concentration of described fluoropolymer nanoparticle, for being greater than about 1g/L, being greater than about 2g/L, or being greater than about 5g/L.

13. electroplating compositions according to any one of claim 1 to 12, wherein, the concentration of described fluoropolymer nanoparticle is at about 1g/L with about between 400g/L, at about 1g/L with about between 200g/L, at about 1g/L with about between 50g/L, at about 1g/L with about between 40g/L, at about 1.5g/L with about between 400g/L, at about 2g/L with about between 200g/L, at about 2g/L with about between 100g/L, at about 2.5g/L with about between 50g/L, at about 2g/L with about between 5g/L, at about 5g/L with about between 200g/L, at about 5g/L with about between 100g/L, at about 5g/L with about between 50g/L, at about 10g/L with about between 110g/L, or at about 10g/L with about between 50g/L.

14. electroplating compositions according to any one of claim 1 to 13, wherein, described fluoropolymer nanoparticle has from about 10nm to about 200nm, from about 50nm to about 150nm, from about 50nm to about 100nm, or from about 10nm to the median size of about 50nm.

15. electroplating compositions according to any one of claim 1 to 14, wherein, at least about 50 volume %, the described fluoropolymer nanoparticle of 70 volume %, 80 volume % or 90 volume % has and is less than 200nm, is less than 100nm, be less than 90nm, be less than 80nm, or be less than the particle diameter of 70nm.

16. electroplating compositions according to any one of claim 1 to 15, wherein, the tensio-active agent of pre-mixing comprises nonionogenic tenside.

17. electroplating compositions according to any one of claim 1 to 16, wherein, the concentration of described silver ions is from about 5g/L to about 300g/L, from about 10g/L to about 200g/L, from about 10g/L to about 100g/L, from about 5g/L to about 50g/L, from about 10g/L to about 50g/L, or from about 20g/L to about 40g/L.

18. electroplating compositions according to any one of claim 1 to 17, wherein, described in there is described nitrogenous heterocyclic compound comprise 5 rings or 6 rings.

19. electroplating compositions according to any one of claim 1 to 18, wherein, described nitrogen heterocyclic ring be selected from by glycolylurea, succinimide, pyridine, dipyridyl, pyrimidine, uridylic, its replace or unsubstituted analogue, its derivative and its combine the group that forms.

20. electroplating compositions according to any one of claim 1 to 19, wherein, described in have described nitrogenous heterocyclic compound be selected from by replace with the group formed with unsubstituted succinimide of unsubstituted glycolylurea and replacement.

21. electroplating compositions according to any one of claim 1 to 20, wherein, described complexing agent comprises succinimide.

22. electroplating compositions according to any one of claim 1 to 21, wherein, described complexing agent comprises the hydantoin compound with structural formula I

In formula, R ¹, R ², R ³, and R ⁴be hydrogen independently, there is 1 alkyl to 5 carbon atoms, there is 1 to the hydroxyalkyl of 5 carbon atoms or replace or unsubstituted aryl.

23. electroplating compositions as claimed in claim 22, wherein, the R of structural formula I ¹, R ², R ³and R ⁴be hydrogen independently, there is 1 alkyl to 5 carbon atoms.

24. electroplating compositions as claimed in claim 23, wherein, R ¹and R ²that there is 1 alkyl to 5 carbon atoms, and R ³and R ⁴be hydrogen independently.

25. electroplating compositions as claimed in claim 22, wherein, structural formula I is selected from following compound: glycolylurea; 1-methyl hydantoin; 1,3-T10; 5,5-T10; 1-methylol-5,5-T10; 5,5-diphenyl hydantoin; With its mixture.

26. electroplating compositions as claimed in claim 22, wherein, structural formula I is 5,5-T10.

27. electroplating compositions according to any one of claim 22 to 26, wherein, the concentration of the hydantoin compound of described structural formula I is at least about 50g/L, at least about 60g/L, at least about 70g/L or at least about 80g/L.

28. electroplating compositions according to any one of claim 22 to 26, wherein, the concentration of the hydantoin compound of described structural formula I is from about 50g/L to about 300g/L, from about 60g/L to about 280g/L, from about 70g/L to about 250g/L, from about 80g/L to about 250g/L or from about 80g/L to about 150g/L.

29. electroplating compositions according to any one of claim 1 to 28, wherein, described electroplating composition also comprises wetting agent, and this wetting agent comprises the 2-Naphthol of the poly-alkoxylation of sulfopropyl, the condensed products of naphthene sulfonic acid or its salt.

30. electroplating compositions as claimed in claim 29, wherein, the concentration of described wetting agent is at least about 5g/L, at least about 10g/L, at least about 15g/L or at least about 20g/L.

31. electroplating compositions as claimed in claim 29, wherein, the concentration of described wetting agent is from about 5g/L to about 50g/L, from about 5 to about 40g/L, from about 10g/L to about 30g/L or from about 10g/L to about 20g/L.

32. electroplating compositions according to any one of claims 1 to 31, wherein, described electroplating composition also comprises the sulfonic acid of concentration between 50g/L and 500g/L, between 100g/L and 300g/L or between 130g/L and 200g/L and/or sulfonic acid.

33. electroplating compositions as claimed in claim 32, wherein, described sulfonic acid and/or sulfonic acid comprise methanesulfonic potassium.

34. electroplating compositions according to any one of claims 1 to 33, wherein, described electroplating composition also comprises about 30mg/L to about 500mg/L or from about 100mg/L to the alkali metal bromide of about 200mg/L.

35. electroplating compositions as claimed in claim 34, wherein, described alkali metal bromide comprises Potassium Bromide.

36. electroplating compositions according to any one of claims 1 to 35, wherein, described electroplating composition also comprises antifoam additive.

37. electroplating compositions according to any one of claims 1 to 36, wherein, the pH value of described composition is from about 9 to about 12.5, from about 9.5 to about 11.5 or from about 9 to about 11.

38. 1 kinds are coated to method on substrate surface for making silver or silver alloys compound coating, and described method comprises:

Described substrate surface is contacted with the electroplating composition such as according to any one of claims 1 to 37, and

Make external electrical source be applied to described electroplating composition to make described compound coating galvanic deposit on described substrate surface thus, wherein, described compound coating comprises silver or silver alloys and fluoropolymer nanoparticle.

39. methods as claimed in claim 38, wherein, described compound coating has from about 0.05 to about 0.5, from about 0.05 to about 0.3 or frictional coefficient from about 0.1 to about 0.2.

40. methods as described in claim 38 or 39, wherein, described compound coating contains the fluorine (atom) of at least 1.2 % by weight, 1.5 % by weight, 1.8 % by weight, 2.0 % by weight, 2.5 % by weight, 3.0 % by weight, 3.5 % by weight or 4.0 % by weight.

41. methods as described in claim 38 or 39, wherein, described compound coating contains from about 2 % by weight to about 7 % by weight, from about 2.5 % by weight to about 5 % by weight or from about 3 % by weight to about 4 % by weight fluorine (atom).

42. methods according to any one of claim 38 to 41, wherein, described compound coating has and is less than about 10 milliohms, is less than about 5 milliohms or is less than the contact resistance of about 2 milliohms.

43. methods according to any one of claim 38 to 42, wherein, described substrate comprises electrical connector.

44. methods according to any one of claim 38 to 43, wherein, described substrate surface comprises copper.

45. methods according to any one of claim 38 to 44, wherein, described substrate surface does not comprise nickel blocking layer.

46. methods according to any one of claim 38 to 45, wherein, described substrate is with from about 0.1A/dm ²to about 10A/dm ², from about 1A/dm ²to about 5A/dm ², or from about 2.5A/dm ²to about 3.5A/dm ²the current density of setting contact with described electroplating composition.

47. methods according to any one of claim 38 to 46, wherein, described compound coating has and is not more than about 20 μm, is not more than about 10 μm, is not more than about 5 μm or be not more than the thickness of about 3 μm.

48. methods according to any one of claim 38 to 47, wherein, described compound coating has from about 0.5 μm to about 10 μm, from about 1 μm to about 10 μm, from about μm to about 5 μm or from the thickness of about 1 μm to about 3 μm.

49. methods according to any one of claim 38 to 48, wherein, described compound coating is with 0.05 μm/min to about 5 μm/min, be deposited from about 0.5 μm/min to about 5 μm/min, from about 1 μm/min to about 5 μm/min or from about 1 μm/min to the plating speed of about 2.5 μm/min.

50. 1 kinds of methods for the preparation of electroplating composition, described method comprises:

(1) complexing agent of hydantoin compound, any one wetting agent and conducting salt and water mixing is made to comprise to form solution;

(2) source of silver ions comprising Ag-MSA is made to be blended in described solution;

(3) cosurfactant and any one alkali metal bromide is made to be blended in described solution;

(4) after step (1) to step (3), make to comprise the pre-mixing dispersed system with the fluoropolymer nanoparticle particle of median size from about 10nm to about 500nm and tensio-active agent and be mixed together in described solution to form described electroplating composition together with any one antifoam additive; With

(5) alternatively by adding alkali, the pH value of described mixture is maintained about 9 to about 10.

51. 1 kinds of copper base substrates, described copper base substrate have above it by the method according to any one of claim 38 to 49 the money base compound coating that deposits.

52. 1 kinds of electrical connector copper base substrates, described electrical connector copper base substrate have above it by the method according to any one of claim 38 to 49 the money base compound coating that deposits.