CN105624745A

CN105624745A - Environmentally friendly gold electroplating compositions and methods

Info

Publication number: CN105624745A
Application number: CN201510809862.3A
Authority: CN
Inventors: A·福伊特; M·克洛斯; R·布克斯
Original assignee: Rohm and Haas Electronic Materials LLC
Current assignee: Rohm and Haas Electronic Materials LLC
Priority date: 2014-11-21
Filing date: 2015-11-20
Publication date: 2016-06-01
Anticipated expiration: 2035-11-20
Also published as: JP6073450B2; TWI600805B; US20160145756A1; EP3023520B1; TW201619446A; KR101712970B1; JP2016117946A; CN105624745B; KR20160061268A; EP3023520A1

Abstract

Gold electroplating compositions are substantially free of many environmental toxins to provide an environmentally friendly pure gold electroplating composition. The substantially pure gold electroplating compositions may electroplate gold over a broad current density range to deposit bright to matte gold layers on various types of electronic components and decorative articles.

Description

The golden electroplating composition of environmental protection and method

Technical field

The present invention be directed to the golden electroplating composition of environmental protection and method. More precisely, the present invention be directed to the golden electroplating composition of environmental protection and method, wherein can in wider current density range electroplating mild alloy, thus even at providing bright soft gold deposit under injection and pulse current plating condition.

Background technology

Electrolyzing gold is typically used in adapter and electronics polish, because gold has superior performance in these application-specific. Gold becomes one of the most trustworthy material for electronic building brick due to its anti-corrosion property, electrical conductivity and heat stability. Substantially pure gold is usually by the cyanide electrolysis plating bath containing some additives and metal brightener. These additives have, such as hydrazine, is poisonous and is subject to now many countries and international regulations restriction. The commercially available proof gold body lotion of major part contains free cyanide and one or more grain refiner, such as arsenic, thallium and lead, these materials known are to environmental toxic, therefore, the refuse thrown aside must separate the gold-plated body lotion of this class, and this is also consuming time and expensive for industry. Additionally, this type of gold electroplating bath is dangerous improperly for using the workman of these body lotions there is also.

Give Mo Lisi (Morrissey) U.S.5,277,790 disclose a kind of gold electroplating bath without cyanide, and wherein gold provides with solubility sulphite complexes form. Although described gold electroplating bath is without cyanide, but it at high temperature undesirably produces sulfur dioxide. Sulfur dioxide is a kind of toxic gas with pungent odour. In order to solve this problem, in described plating solution, add even more sulphite. Additionally, gold is with about 0 to 30mA/cm²Relatively low plating rates plating. Accordingly, it would be desirable to the gold electroplating bath of a kind of improvement, described electroplating bath is environmental protection and can carry out plating in wider current density range.

Summary of the invention

Gold electroplating composition includes one or more from the gold ion source of gold cyanide salt, one or more phosphate ion sources, one or more phosphonic acids or its salt source, sodium potassium tartrate tetrahydrate and one or more antimony (III) ion source, and described gold electroplating composition is substantially free of free cyanide.

The method of electrogilding includes providing gold electroplating composition, described gold electroplating composition includes one or more from the gold ion source of gold cyanide salt, one or more phosphate ion sources, one or more phosphonic acids or its salt source, sodium potassium tartrate tetrahydrate and one or more antimony (III) ion source, and described gold electroplating composition is substantially free of free cyanide; Substrate is made to contact with described gold electroplating composition; And use DC current or pulse current, electrogilding over the substrate under 0.03ASD or the electric current density more than 0.03ASD.

Described gold electroplating composition be environmental protection and can in wider current density range, including under high velocity jet plating condition, the soft gold deposit that plating is bright. Described soft gold deposit also has fine grain structure. The compositions of electrogilding may be used for plating gold striking layer (goldstrikelayer) on electronic building brick, and may be used for electroplating mild alloy layer to form the joint of adapter and to form layer gold on exchanger or printed circuit board (PCB). Described gold electroplating composition can be also used for deposition soft gold layer on decorative article. Described gold deposit also has fine grain structure. Less granular size makes the porosity in thin film reduce. The brightness of described deposit is also the direct result of the granular size that this is less. In general, compared to smooth bright deposit, matt or half bright deposit roughness is higher.

Accompanying drawing explanation

Fig. 1 is the SEM under 20,000 amplifications, it is shown that with the microstructure of the soft gold deposit that the golden electroplating composition containing antimony (III) ion is electroplated.

Fig. 2 is the SEM under 20,000 amplifications, it is shown that with the microstructure containing the plumbous golden deposit electroplated as the conventional gold electroplating bath of grain refiner.

Detailed description of the invention

Unless context is separately explicitly indicated, otherwise as this specification in the whole text use, below abbreviation should have following implication: DEG C=degree Celsius; G=gram; Mg=milligram; L=liter; ML=milliliter; Em=centimetre; Mm=millimeter; ��m=micron (microns/micrometers); Ppb=parts per billion (ppb); Ms=millisecond; DC=DC current; ASD=ampere/square decimeter=A/dm²; And ASTM=American standard test method (AmericanStandardTestingMethod).

Term " plating " and " plating " are used interchangeably in the whole text in this specification. Term " compositions ", " solution " and " body lotion " is used interchangeably in the whole text in this specification. Term " one (kind) " refers to odd number and plural number.

Unless otherwise noted, otherwise all percentage ratios are all by weight. All numerical rangies all include end points and can be combined in any order, but this kind of numerical range is restricted to total totally 100% in logic.

Compositions includes the gold ion from one or more gold cyanide salt, such as alkali metal gold cyanide compound, such as potassium auricyanide, gold sodium cyanide and Aurous cyanide ammonium. Preferred as alkali gold cyanide compound is potassium auricyanide. Although gold ion is to be provided by gold cyanide salt, but it is not added with free cyanide in gold electroplating composition, such as alkali metal cyanide salt, or any salt of the be provided that free cyanide ligand except gold salt.

Except gold cyanide salt, it is possible to by alkali metal gold thiosulfate compound, such as gold aurothiosulfate trisodium and gold aurothiosulfate tripotassium; Gold halogenide, as auric chloride, tetra chlorauric acid and Auric chloride. provide other gold ion. Preferred gold ion is only provided by gold cyanide salt. This type of gold compound is generally purchased from multiple supplier, maybe can be prepared by method well known in the art.

Add the amount that the amount of the gold salt in described compositions is to provide the gold ion of desired concentration to. In general, the amount of gold ion is 4g/L to 20g/L, it will be preferred that 8g/L to 20g/L, is more preferably 15g/L to 20g/L. In electroplating composition, the amount of gold ion depends on the type of plating, such as injection plating, rack plating or barrel plating.

Described gold electroplating composition includes Conductive inorganic acid and its salt. This type of electric conductivity acid includes but not limited to, phosphoric acid, sulphuric acid and hydrochloric acid, and salt. Preferably, the acid of described Conductive inorganic and its salt are selected from phosphoric acid and potassium dihydrogen phosphate, sodium dihydrogen phosphate, potassium phosphate, sodium phosphate, and mixture. Preferably, when using potassium phosphate, add phosphoric acid.

Alkali compounds can also be added so that the pH value of described compositions maintains 5 to 6.8, it is preferable that 5.8 to 6.7, it is more preferred to the level of hope of 6 to 6.3. This type of alkali compounds includes but not limited to, the hydroxide of sodium, potassium and magnesium, carbonate and other salt. For example, NaOH, KOH, K₂CO₃��Na₂CO₃��NaHCO₃And mixture is applicable alkali compounds. Typically, the amount of included basic matterial is 1g/L to 100g/L.

Including organic phosphorus compound as the chelating agen of gold ion in gold electroplating composition. Its in the pH value range of gold electroplating composition deprotonation and with gold ion chelating, and the sequestering power of these compounds is enough good makes gold compositions stable so that the free cyanide from potassium cyanide or Cyanogran. need not be added.

Organic phosphorus compound includes those compounds with following formula:

Wherein n is the integer of 2 to 3, includes 2 and 3, M₁And M₂Can be identical or different and selected from hydrogen; Ammonium; There is 1-9 carbon atom, preferably there is the lower alkyl groups amine of 1-5 carbon atom or alkali metal cation, such as sodium, potassium and lithium, preferred described alkali metal cation is potassium or sodium, and Z is group that valence state is identical with n and is straight chain or branched chain, substituted or unsubstituted (C₁-C₁₂) (the C that is replaced of alkyl or N-₂-C₃) alkyl, the carbon atom of wherein said Z group is connected to the phosphorus atoms of formula (I). Preferably, Z is straight chain or branched chain, substituted or unsubstituted (C₁-C₄) alkyl, wherein said substituent group is hydroxyl. The amount of this included compounds is 5g/L to 200g/L, it will be preferred that 20g/L to 150g/L, is more preferably 50g/L to 120g/L.

A compounds within the scope of formula above includes amino three (low carbon number alkylene phosphonic acids). The example of this compounds includes amino three (methylene phosphonic acid), amino three (ethylidene phosphonic acids), amino three (isopropylidene phosphonic acids), amino two (methylene phosphonic acid) single (ethylidene phosphonic acids), amino two (methylene phosphonic acid) single (isopropylidene phosphonic acids), amino list (methylene phosphonic acid) two (ethylidene phosphonic acids) and amino list (methylene phosphonic acid) two isopropylidene phosphonic acids.

Low carbon number alkylidene bisphosphonate compound within the scope of above formula is methylenediphosphonate, ethylidene diphosphonic acid, secondary isopropyl di 2 ethylhexyl phosphonic acid (isopropylenediphosphonicacid), isopropylidene di 2 ethylhexyl phosphonic acid, 1 hydroxyethylidine diphosphonate, 1-hydroxy propylidene di 2 ethylhexyl phosphonic acid, butylidene di 2 ethylhexyl phosphonic acid.

Particularly preferred organic phosphorus compound is 1 hydroxyethylidine diphosphonate four potassium, 1 hydroxyethylidine diphosphonate four sodium and hydroxyethylidine-1,1-di 2 ethylhexyl phosphonic acid.

Including antimony (III) ion be antimony potassium tartrate and the form of the combination of sodium potassium tartrate tetrahydrate. Although can add in antimony chloride or the antimony of Antimonous sulfate form (III) ion, but the antimony (III) preferably added is antimony tartrate form. The amount adding antimony (III) salt in gold electroplating composition to should provide 1mg/L to 20mg/L, it is preferable that antimony (III) ion of 5mg/L to 15mg/L. The amount adding the sodium potassium tartrate tetrahydrate in gold electroplating composition to is 10g/L to 50g/L, it will be preferred that 15g/L to 35g/L. The other tartrate added in gold electroplating composition can be the form of tartaric acid, Soluble tartar. or other water solublity tartrate and compound, and its amount is about specified by sodium potassium tartrate tetrahydrate; But, in order to prevent antimony (III) ion-oxygen chemical conversion antimony (V) ion, it is most preferred that tartrate source be sodium potassium tartrate tetrahydrate. In situation without being bound by theory, the existence of antimony (III) ion can provide bright golden deposit, even under injection plating condition. Additionally, antimony can provide soft gold deposit.

Optionally, gold plating coating composition can include one or more organic acid, such as citric acid, malic acid, oxalic acid, formic acid or polyethylene glycine; Or mineral acid, such as phosphoric acid. These acid contribute to making the pH value of described compositions maintain in desired scope. Typically, the amount of included acid is 1g/L to 200g/L.

Optionally, multiple other golden chelating agen or chelating agent can be included in the composition. The golden chelating agent being suitable for includes but not limited to, thiosulfuric acid; Thiosulfate, such as sodium thiosulfate, Potassium hyposulfite., potassium sorbate and Ammonium hyposulfite.; Ethylenediaminetetraacetic acid and salt thereof; Imine oxalic acid and nitrilotriacetic acid.

One or more the other chelating agen described or the chelating agent that add can be convention amounts, or such as 1g/L to 100g/L, or such as the amount of 10g/L to 50g/L. One or more chelating agent described are usually commercially available or can be prepared by method well known in the art.

Described compositions can also include one or more surfactants. Any applicable surfactant may be used in described compositions. These surfactants include but not limited to, alkoxyalkyl sulfate (alkyl ether sulfate) and alkoxyalkyl phosphate (alkyl ether phosphate). Described alkyl and alkoxyl typically contain 10 to 20 carbon atoms. The example of this type of surfactant is sodium lauryl sulfate, caprylyl sodium sulfate, myristyl sulfate, C₁₂-C₁₈The ether sodium sulfate of straight chain alcohol, lauryl ether sodium phosphate and corresponding potassium salt.

Other applicable surfactant operable includes but not limited to N-oxide surfactant. This type of N-oxide surfactant includes but not limited to, cocoyl dimethyl amine n-oxide, lauryl dimethyl amine N-oxide, oleyldimethylamine N-oxide, dodecyl-dimethyl amine N-oxide, octyldimethyl amine n-oxide, double; two-(ethoxy) isodecyloxypropyl amine n-oxide, decyldimethyl amine N-oxide, acylamidopropyldimethyl amine n-oxide, double; two (ethoxy) C₁₂-C₁₅Alkoxypropan amine n-oxide, lauryl amine n-oxide, lauroyl amido propyl-dimethyl amine N-oxide, C₁₄-C₁₆Alkyl Dimethylamine N-oxide, N, N-dimethyl (hydrogenated tallow alkyl) amine n-oxide, isostearoyl aminocarbonyl propyl morpholine N-Oxide and isostearoyl aminocarbonyl propyl pyridine N-oxides.

Other surfactant being suitable for includes but not limited to, glycine betaine, and alcoxylates, such as ethylene oxide/propylene oxide (EO/PO) compound. This type of surfactant is well known in the art.

Many surfactants can be commercially available or be prepared by the method described in document. Typically, the amount including surfactant in the composition is 0.1g/L to 20g/L.

The component of described compositions can pass through any appropriate methodology as known in the art combination. Typically, mix described component in any order and make compositions reach desired volume by adding enough water. It is likely to need certain heating to dissolve some composition component. Gold electroplating composition is substantially free of arsenic, lead, thallium, hydrazine and sulphite. In general, be substantially free of and be meant to utilize the most conventional analytical equipment to be not easy to described metal, hydrazine and sulphite be detected, if or its be detectable, then its content is 100ppb or lower than 100ppb.

In general, using DC or pulse plating, electric current density can in 0.03ASD and the scope higher than 0.03ASD. Applying for barrel plating, use DC electric current, electric current density can be 0.05ASD to 2.5ASD. Gold ion concentration is preferably in 4g/L to 8g/L scope. Applying for rack plating, use DC electric current, electric current density can in 0.05ASD to 4ASD scope. Gold ion concentration is preferably in 8g/L to 12g/L scope; But, for rack plating, when using pulse current, applicable electric current density can expand 6ASD to, and wherein on-off time ratio (ON: OFFtime) is 1: 3ms. When utilizing injection plating apparatus to carry out injection plating, gold ion concentration is preferably in 12g/L to 20g/L scope. Bright deposit can be obtained by the on-off ratio pulse parameter of the pulse peak current of 2ASD to 70ASD and 1: 1 to 1: 4ms. Depending on the electric current density applied, injection stirring can change between 100 ls/h to 1000 ls/h. Stir at a high speed preferably in using under relatively high impulse peak point current. By adjusting gold concentration and plating parameter, soft gold electroplating composition may be used in rack plating, barrel plating and high velocity jet plating. Different from the proof gold electroplating composition of many routines, described gold electroplating composition can for gold deposition at a high speed together with injection plating apparatus. Injection plating or the plating carried out under higher current density comparatively fast and make the electroplating efficiency on production line increase to some extent compared to the plating carried out under lower current densities. This type of high velocity jet method for plating is that production in enormous quantities is in demand.

Except bright deposit is provided at higher current densities, the soft gold deposit that described soft gold electroplating composition deposition is substantially homogeneous. Gold hardness typically represents with Knoop hardness (knoophardness) value and represents the meansigma methods of the multinomial test using 25 grams of indentation instruments to carry out. When plated, Knoop hardness is 91 to 129, i.e. the B eka-gold according to ASTMB488-11. After anneal, Knoop hardness is 78 or A eka-gold. The purity of gold deposit is 99.9% and is Group III purity.

Plating time can change. Time quantum depends on the hope thickness of gold on substrate. Typically, the thickness of gold is 0.01 micron to 50 microns, or such as 0.1 micron to 2 microns, or such as 0.2 micron to 0.5 micron.

Golden plating apparatus electrogilding on substrate of routine can be used. Anode is insoluble anode, such as rustless steel, platinum, the tantalum of bag platinum, the titanium of platinum plating and graphite. Preferably, anode is the Ni?Ti anode of platinum plating.

Soft gold electroplating composition can be used to power on Gold plated Layer at metals such as such as nickel, nickel alloy, copper, copper alloy, stannum and ashbury metals. Preferably, use gold electroplating composition at nickel and nickel alloy, such as electrogilding on joint, adapter, exchanger and printed circuit board (PCB). Described gold electroplating composition can be also used for plating layer gold on the decorative articles such as such as jewelry. Gold electroplating composition can be also used for the plating striking layer cohesiveness to improve between metal level on substrate.

Described soft gold electroplating composition is environmental protection and can use DC or pulse current and under barrel plating, rack plating or injection plating condition, the golden deposit that plating is bright in applicable current density range. Described gold deposit also has fine grain structure. Less granular size makes the porosity in thin film reduce. The brightness of described deposit is also the direct result of the granular size that this is less. In general, compared to smooth bright deposit, matt or half bright deposit roughness is higher.

The following instance meant for illustration present invention, but it is not limiting as its scope.

Example 1

Preparation has the soft gold electroplating bath of aqueous of consisting of:

Table 1

Component	Amount
		Gold from potassium auricyanide	8g/L
Potassium dihydrogen phosphate	79g/L
		Hydroxyethylidine-1,1-di 2 ethylhexyl phosphonic acid	113g/L
Potassium hydroxide	64g/L
		KATHONE^TMLXE Biocide¹	50mg/L
Sodium potassium tartrate tetrahydrate	20g/L
		Antimony (III) from antimony potassium tartrate	8mg/L (antimony (III))

¹The chloro-2 methyl-4-isothiazole-3-ketone of 5-, magnesium nitrate, copper nitrate and 2-methyl-2H-isothiazole-3-ketone, buy from the Dow Chemical (TheDowChemicalCompany, Midland, MI) being positioned at available.

By five 15 �� 20mm²Copper-plated in advance two-sided nickel test panel immerse in the body lotion of the soft gold electroplating bath of 500mL, keeps 3 minutes, golden with plating on nickel. Anode is the Ti electrode of platinum plating. Whole 3 minutes periods, magnetic stirring apparatus is used to stir body lotion. The pH value of body lotion be 6.2 and the temperature of body lotion be 55 DEG C. Apply DC electric current and electric current density is 1ASD. After 3 minutes sections, from body lotion, take out test piece, by deionized water rinsing air drying. Gold deposit is bright. With XDV-SD type FISHERSCOPE^TMX-ray equipment is measured the thickness of gold deposit and is determined as 1.7 microns. Then, use SEM microscope, under 20,000 amplifications, analyze the microstructure of gold deposit in described panel. Fig. 1 shows one of SEM with the acquirement of described microscope. SEM demonstrates less grain structure.

Example 2 (comparison)

Preparation has the aqueous gold electroplating bath of formula as below:

Table 2

Component	Amount
		Gold from potassium auricyanide	8g/L
Potassium dihydrogen phosphate	79g/L
		Hydroxyethylidine-1,1-di 2 ethylhexyl phosphonic acid	113g/L
Potassium hydroxide	64g/L
		KATHONE^TMLXE Biocide	50mg/L
Acetic acid	5g/L
		Three acetate hydrate are plumbous	6mg/L (in lead)

By five 15 �� 20mm²Copper-plated in advance two-sided nickel test panel immerse in the body lotion of 500mL gold electroplating bath, keeps 3 minutes, golden with plating on nickel. Anode is the Ti electrode of platinum plating. Whole 3 minutes periods, magnetic stirring apparatus is used to stir body lotion. The pH value of body lotion be 6.2 and the temperature of body lotion be 55 DEG C. Apply DC electric current and electric current density is 1ASD. After 3 minutes sections, from body lotion, take out test piece, by deionized water rinsing air drying. The thickness of gold deposit is 1.7 microns. Then, use SEM microscope, under 20,000 amplifications, analyze the microstructure of gold deposit in described panel. Fig. 2 shows one of SEM with the acquirement of described microscope. SEM demonstrates coarse grain structure. The optical appearance that this microstructure becomes clear with described deposit half is consistent. Be not so good as the golden electroplating composition of example 1 by the grain structure of the gold of table 2 plating and optical appearance, test panel is with containing from the gold plating in the antimony (III) and lead-free electroplating bath of antimony potassium tartrate and sodium potassium tartrate tetrahydrate in example 1.

Example 3

By eight 15 �� 20mm²Copper-plated in advance two-sided nickel test panel immerse respectively in the body lotion of the 500mL electroplating bath containing formula in the table 1 with example 1. Anode is the Ti electrode of platinum plating. For each body lotion, electrogilding 3 minutes on nickel. During whole plating time, magnetic stirring apparatus is used to stir body lotion. The pH value of body lotion be 6.2 and the temperature of body lotion be 55 DEG C. Apply the electric current density between DC electric current and each panel different. Electric current density is 0.5ASD, 1.2ASD, 1.5ASD, 2ASD, 2.5ASD, 3ASD, 3.5ASD and 4ASD. After plating, from body lotion, take out panel, by deionized water rinsing air drying. All gold deposits all have bright outward appearance.

Repeat electroplating technology described above, but use the gold electroplating bath of the table 2 of example 2 instead. After plating, with the golden deposit of 0.5ASD to 3ASD plating, there is half bright deposit; But, under 3.5ASD and 4ASD, the gold utensil of plating has the outward appearance in intensely dark pool. Result shows, so that it may the electric current density of application and outward appearance, and the gold electroplating bath of table 1 is compared to the plating properties containing plumbous gold electroplating bath with improvement of table 2.

Example 4

The preparation soft Gold electrolysis plating bath as shown in following table:

Table 3

Component	Amount
		Gold from potassium auricyanide	20g/L
Potassium dihydrogen phosphate	79g/L
		Hydroxyethylidine-1,1-di 2 ethylhexyl phosphonic acid	113g/L
Potassium hydroxide	64g/L
		KATHONE^TMLXE Biocide	50mg/L
Sodium potassium tartrate tetrahydrate	20g/L
		Antimony (III) from antimony potassium tartrate	10mg/L (antimony (III))

By 15 �� 20mm²Copper-plated in advance two-sided nickel test panel be placed in containing on the injection plating apparatus of the soft gold electroplating bath of 1000mL table 3. Anode is the Ti electrode of platinum plating. The pH value of body lotion be 6.2 and the temperature of body lotion be 60 DEG C. Applying pulse current and peak current density is 50ASD, on-off time ratio is 1: 3ms. This is corresponding to the average current density of 12.5ASD. Injection is stirred or flow rate is set to 800 ls/h. After the plating time section of 10 seconds, from body lotion, take out panel, by deionized water rinsing air drying. All panels all have bright golden deposit.

Repeat described technique with the gold electroplating bath of table 2, but the amount of gold ion is 20g/L gold. Injection described above is used to stir and plating parameter. Gold deposit has substantially matt or calcination outward appearance. Repeat described test, but pulse peak current density be 30ASD and flow rate same as described above. This is corresponding to the average current density of 7.5ASD. All deposits are all lacklustre. The electroplating bath of table 2 under injection is stirred, do not provide at higher current densities bright or or even half bright golden deposit, therefore, the performance of described gold body lotion is not as the golden plating body lotion of table 3.

Claims

1. a golden electroplating composition, described compositions comprises one or more from the gold ion source of gold cyanide salt, one or more phosphate ion sources, one or more phosphonic acids or its salt source, sodium potassium tartrate tetrahydrate and one or more antimony (III) ion source, and described gold electroplating composition is without free cyanide.

2. gold electroplating composition according to claim 1, wherein said gold cyanide salt is selected from potassium auricyanide, gold sodium cyanide and Aurous cyanide ammonium.

3. gold electroplating composition according to claim 1, one or more phosphate ion sources wherein said are selected from phosphoric acid, sodium dihydrogen phosphate and potassium dihydrogen phosphate.

4. gold electroplating composition according to claim 1, one or more phosphonic acids wherein said have following formula:

Wherein n is the integer of 2 to 3, M₁And M₂Can be identical or different and selected from hydrogen, ammonium, lower alkyl groups amine or alkali metal cation, and Z is group that valence state is identical with n and is straight chain or branched chain, substituted or unsubstituted (C₁-C₁₂) (the C that is replaced of alkyl or N-₂-C₃) alkyl, the carbon atom of wherein said Z group is connected to the phosphorus atoms of formula (I).

5. gold electroplating composition according to claim 1, wherein said one or more antimony (III) ion source is selected from antimony potassium tartrate, Antimony sodium oxide L(+)-tartrate, Antimonous sulfate and antimony chloride.

6. gold electroplating composition according to claim 1, wherein said gold electroplating composition is substantially free of lead, arsenic, thallium, hydrazine and sulphite.

7. a method for electrogilding, described method includes:

A., gold electroplating composition is provided, described compositions comprises one or more from the gold ion source of gold cyanide salt, one or more phosphate ion sources, one or more phosphonic acids or its salt source, sodium potassium tartrate tetrahydrate and one or more antimony (III) ion source, and described gold electroplating composition is substantially free of free cyanide;

B. substrate is made to contact with described gold electroplating composition; And

C. DC current or pulse current are used, under 0.03ASD or the electric current density more than 0.03ASD, electrogilding over the substrate.

8. the method for electrogilding according to claim 7, wherein said electric current density is 1ASD to 50ASD.

9. the method for electrogilding according to claim 7, wherein said gold cyanide salt is selected from potassium auricyanide, gold sodium cyanide and Aurous cyanide ammonium.

10. the method for electrogilding according to claim 7, one or more phosphate ion sources wherein said are selected from phosphoric acid, sodium dihydrogen phosphate and potassium dihydrogen phosphate.

11. the method for electrogilding according to claim 7, one or more phosphonic acids wherein said have following formula:

12. the method for electrogilding according to claim 7, wherein said one or more antimony (III) ion source is selected from antimony potassium tartrate, Antimony sodium oxide L(+)-tartrate, Antimonous sulfate and antimony chloride.

13. the method for electrogilding according to claim 7, wherein said gold electroplating composition is substantially free of free cyanide, lead, arsenic, thallium, hydrazine and sulphite.

14. the method for electrogilding according to claim 7, wherein said substrate is printed circuit board (PCB), for the joint of adapter, switch or decorative article.