CN1995472A - Gold citrate for glod plating - Google Patents
Gold citrate for glod plating Download PDFInfo
- Publication number
- CN1995472A CN1995472A CN 200610134865 CN200610134865A CN1995472A CN 1995472 A CN1995472 A CN 1995472A CN 200610134865 CN200610134865 CN 200610134865 CN 200610134865 A CN200610134865 A CN 200610134865A CN 1995472 A CN1995472 A CN 1995472A
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- CN
- China
- Prior art keywords
- gold
- salt
- citric acid
- citrate
- dicyan
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- Electroplating And Plating Baths Therefor (AREA)
Abstract
The invention discloses a gold plating gold citrate, which is blended by dicyanoaurate and citrate with chemical component as Mau (CN) 2 (M3C6H5O7 .k1C6H8O7) k2, wherein M represents monovalent cation from one or composition of K+,Na+,NH4+; Mau (CN) 2 is dicyanoaurate; M3C6H5O7 .k1C6H8O7 is citrate; k1 is between 0 and 5; k2 is between 0.3 and 5.
Description
Technical field
The present invention relates to a kind of gold-plated main salt that is used for, particularly a kind of citric acid gold salt that is used for electrogilding or chemical gilding, it mainly is applicable to acidity and neutral gold plating technology.
Background technology
Gold-platedly be widely used industrial.Craft of gilding can divide three classes substantially: alkaline cyanide is gold-plated, sulphite is gold-plated, acidity and neutral gold-plated.Alkaline cyanide is gold-plated to be complexing agent because it uses the KCN of severe toxicity, is unfavorable for safety and environmental protection, so range of application is subjected to strict restriction.Sulphite is gold-plated poor because of bath stability, and the production cost height does not obtain extensive use, and current most popular craft of gilding is acid and neutral gold-plated.
Acid and neutral gold plating technology is used dicyan network potassium aurate [chemical formula KAu (CN) usually
2, have another name called potassium cyanaurite, be commonly called as golden salt] be main salt (see " process of surface treatment complete works " the 290th page for details, the Liu Yubo chief editor, China Measuring Press, in May, 1996 first version).This technology is quantitatively replenished dicyan network potassium aurate according to the consumption of gold.There is following deficiency in it: in the gold-plated process, because consumption and the gold-plated workpiece of electrode reaction are put into, taken out the washing loss that causes, cause gold and citrate in the plating bath simultaneously all lossy.This technology uses dicyan network potassium aurate to be main salt, the just simple loss that replenishes gold, and the loss of citrate needs to replenish in addition in the plating bath.Because commercially available Citrate trianion kind is single, its pH value often differs bigger with the plating bath pH value, thus usually after adding Citrate trianion, also need to adjust separately the pH value of plating bath, cumbersome.In addition, dicyan network potassium aurate belongs to highly toxic substance, gives to use and management brings inconvenience.In addition, in the actual production, need gold-plated primer mostly to be nickel coating.The nickel dam surface generates passivating film NiO easily in air, affect the combination of Gold plated Layer and nickel bottom.
Summary of the invention
The purpose of this invention is to provide a kind of gold-plated citric acid gold salt that is used for, in acid and neutral gold plating technology, substitute dicyan network potassium aurate with it, adding in plating bath when citric acid gold salt replenishes gold and consume, the pH value of plating bath is stablized in the consumption that also can replenish Citrate trianion, thereby improve the stability of plating bath, significantly improve binding force of cladding material and gold plating quality, to compare toxicity lower with dicyan network potassium aurate for it, so use comparatively safe, help environmental protection, manage convenient.
The object of the present invention is achieved like this: adopt citric acid gold salt to substitute dicyan network potassium aurate in acid and neutral gold plating technology, its technical essential is: described citric acid gold salt is the hybrid junctions crystal of dicyan network aurate and citric acid acid salt, and its chemical composition is MAu (CN)
2(M
3C
6H
5O
7K
1C
6H
8O
7) k
2, M represents monovalent cation K in the formula
+, Na
+, NH
4 +In a kind of or its combination, MAu (CN)
2Be dicyan network aurate; M
3C
6H
5O
7K
1C
6H
8O
7Being the acid salt of citric acid, is by citric acid C
6H
8O
7With citrate M
3C
6H
5O
7Mix k
1Be the molar ratio 0≤k of the two
1≤ 5; K
2Molar ratio 0.3≤k for citric acid acid salt and dicyan network aurate
2≤ 5.
Because the present invention is in acid and neutral gold plating technology, adopt citric acid gold salt to substitute dicyan network potassium aurate as gold-plated main salt, and citric acid gold salt is the hybrid junctions crystal of dicyan network aurate and citric acid acid salt, so when in plating bath, adding the additional gold consumption of citric acid gold salt, also can replenish the consumption of Citrate trianion, stablize the pH value of plating bath, thereby improve the stability of plating bath.In the actual production, need gold-plated primer mostly to be nickel layer.The nickel dam surface generates passivating film NiO easily in air, affect the combination of Gold plated Layer and nickel bottom.Citrate is to Ni
2+Very strong complex ability is arranged, its stability constant β=2 * 10
14, therefore, Citrate trianion can be removed the passive film on nickel dam surface, improves the bonding force and the gold plating quality of Gold plated Layer and nickel bottom.Citric acid gold salt MAu (CN)
2(M
3C
6H
5O
7K
1C
6H
8O
7) k
2Contain CN in the composition
-, generally, CN
-Severe toxicity.Because it also contains monovalence gold ion Au in forming simultaneously
+With citrate C
6H
5O
7 3-, exist in the time of gold ion and citrate ion and significantly reduced contained CN in the component
-Toxicity.Rat test KAu (CN)
2K
3C
6H
5O
70.5C
6H
8O
7The acute oral median lethal dose be LD
50=80mg/kg, its toxicity significantly is lower than simple cyanide, has not belonged to extremely toxic substance.To compare toxicity lower with dicyan network potassium aurate for it, so use comparatively safely, is conducive to environmental protection, manages convenient.
Embodiment
Describe concrete structure of the present invention in detail in conjunction with following embodiment.Adopt citric acid gold salt to substitute dicyan network potassium aurate in acid and neutral gold plating technology, this citric acid gold salt is the hybrid junctions crystal of dicyan network aurate and citric acid acid salt, and its chemical composition is MAu (CN)
2(M
3C
6H
5O
7K
1C
6H
8O
7) k
2, M represents monovalent cation K in the formula
+, Na
+, NH
4 +In a kind of or its combination, MAu (CN)
2Be dicyan network aurate; M
3C
6H
5O
7K
1C
6H
8O
7Being the acid salt of citric acid, is by citric acid C
6H
8O
7With citrate M
3C
6H
5O
7Mix k
1Be the molar ratio 0≤k of the two
1≤ 5; K
2Molar ratio 0.3≤k for citric acid acid salt and dicyan network aurate
2≤ 5.
K in the formula
1Determine the pH value of product, k
1Be worth more greatly, the acidity of product is just more high.Work as k
1＞5 o'clock, product acidity was then strong excessively, the gold plate tarnish, and gold-plated effect obviously reduces.As long as select appropriate k
1Value just can make the pH value of citric acid gold product salt consistent with the pH value of user's plating bath or approaching.Like this, the user can make the pH value of plating bath keep stable when adding the consumption of the additional gold of citric acid gold salt in the plating bath of coating bath simultaneously.For example, gold-plated user's plating bath pH value between 5.0-5.2, the k of corresponding citric acid gold product salt with it
1Value is 0.5, if cation all is potassium, its chemical composition can be shown KAu (CN)
2(K
3C
6H
5O
70.5C
6H
8O
7) k
2The pH value of this product itself is 5.1, and has certain surge capability, and the pH value of plating bath is stabilized in about 5.1.
K in the formula
2Be the molar ratio of citrate in the hybrid junctions crystal and dicyan network aurate, k
2The size of value determines according to gold-plated user's characteristics.k
2Be worth more greatly, the content of citrate is more high in the product.In fact, more or less all contain citrate in many acidity and the neutral gold-plated plating bath.If citrate content is lower or do not contain Citrate trianion, k in the gold-plated plating bath
2Get low value; Plate thick golden user, in the production Citrate trianion loss slower, k
2Get low value; Otherwise choose high value.Like this, add citric acid gold salt, when replenishing the loss of gold, the loss of citrate has also obtained replenishing, and plating bath is more stable, uses more convenient.Usually with 0.3≤k
2≤ 5 are advisable.In addition, the toxicity of citric acid gold salt and k
2Be worth relevant.k
2Be worth more greatly, toxicity is more low.The k of actual product
2Value is compared with dicyan network potassium aurate between 0.3～5, and the toxicity of citric acid gold salt is lower, uses comparatively safely, manages more conveniently, is more suitable for gold-plated user's needs.
Citric acid gold salt is the hybrid junctions crystal of dicyan network aurate and citric acid acid salt, and its manufacture method has two kinds of eutectic method and hybrid systems.Its eutectic method is that Citrate trianion, citric acid are dissolved in hot water in proportion with dicyan network aurate, promptly separates out uniform hybrid junctions crystal after the cooling.Hybrid system: with dicyan network aurate, Citrate trianion, the thin brilliant mixing of citric acid adds the aqueous solution mixing of water or adding citric acid salt again, makes to generate uniform hybrid junctions crystal.Actual product can contain moisture, comprises crystal water.
Substitute golden salt with citric acid gold salt and be used for acidity and neutral gold plating technology, its using method is:
1. open cylinder (new plating bath preparation)
(1) by the golden salt amount of former need (or gold amount), according to chemical formula conversion citric acid gold salt addition m
1
(2) according to m
1Calculate the citrate amount m that brings into simultaneously
2
(3) from former Citrate trianion total amount, deduct m
2, as the actual add-on (maintenance Citrate trianion total amount is constant) of Citrate trianion.
All the other operation stepss are constant.
2. mend cylinder (solution composition replenishes in the production process)
Need to add golden salt amount (or gold amount) according to chemical formula conversion citric acid gold salt addition by former.
Since replenished the consumption of citrate in the plating bath simultaneously, citrate dope in the plating bath, and two important indicators of pH value are more stable, can improve gold plating quality, prolong the adjustment cycle of citric acid salt concentration and pH value, use more convenient.
The composition of citric acid gold salt will adapt to craft of gilding during actual production.Should select appropriate k
1Value makes the pH value of product consistent with the pH value of plating bath or approaching, selects appropriate k
2Value improves the stability of citric acid salt concentration in the plating bath.Monovalent cation K
+, Na
+, NH
4 +Little to gold-plated influence, can substitute mutually usually, not necessarily require consistent with the positively charged ion of plating bath.
Embodiment one is thick metal plated
| Main salt composition | KAu (CN) 2 | KAu (CN) 2K 3C 6H 5O 70.5C 6H 8O 7 |
| Open cylinder | Dicyan network potassium aurate 40g/l citric acid 18g/l potassium citrate 40g/l PH 5.0-5.8 | Citric acid gold salt 96g/l |
| Mend cylinder | 1. every consumption 1g gold is mended KAu (CN) 22. 1.46g detect a citrate content every day and transfer one time pH value additional 3. every days | 1. every consumption 1g gold is mended citric acid gold salt 3.5g 2. and is detected weekly citrate content one time |
From above comparison example as can be known, use citric acid gold salt to be main salt, open cylinder and mend cylinder all greatly easy, and plating bath ingredient stability in gold-plated process, gold-plated effective.
Embodiment two plating thin gold
| Main salt composition | KAu (CN) 2 | KAu (CN) 2[(NH 4) 3C 6H 5O 70.5C 6H 8O 7] 3 |
| Open cylinder | Dicyan network potassium aurate 6g/l diammonium hydrogen citrate 120g/l potassium antimony tartrate 0.1g/l | Citric acid gold salt 27g/l diammonium hydrogen citrate 100g/l potassium antimony tartrate 0.1g/l |
| PH 5.0-5.6 | PH5.0-5.6 | |
| Mend cylinder | 1. every consumption 1g gold is added KAu (CN) 22. 1.46g detect a citrate content every day and transfer one time pH value additional 3. every days | 1. every consumption 1g gold is added citric acid gold salt 6.6g 2. citrate content of detection in per 2 days and is replenished PH of 3. per 2 days accent |
From above comparison example as can be known, use citric acid gold salt to mend cylinder, the citrate content of plating bath and pH value can be adjusted from original every day and once change adjustment in per two days into once, and bath element is more stable.
Embodiment three chemical gildings
| Main salt composition | KAu (CN) 2 | KAu (CN) 2(Na 3C 6H 5O 7) 5 |
| Open cylinder | Dicyan network potassium aurate 5g/l natrium citricum 50g/l ammonium chloride 75g/l nickel chloride 15g/l PH7.-7.5 | Citric acid gold salt 27g/l natrium citricum 30g/l ammonium chloride 75g/l nickel chloride 15g/l PH7.-7.5 |
| Mend cylinder | 1. every consumption 1g gold is added dicyan network potassium aurate 1.46g and is detected a citrate content 2. every days and replenish and transfer one time pH value 3. every days | 1. every consumption 1g gold is added citric acid gold salt 8.0g 2. citrate content of detection in per 2 days and is replenished PH of 3. per 2 days accent |
From above comparison example as can be known, use citric acid gold salt to mend cylinder, the citrate content of plating bath and pH value can be adjusted from original every day and once be extended for adjustment in per two days once, and bath element is more stable.
Embodiment tetracid plating thin gold
Plating bath PH=3.5, Gold Content 0.8g/l, because workpiece is special, the Citrate trianion loss is big when gold-plated.The golden salt of former employing is main salt, and citrate need per hour be added once.Use citric acid gold salt KAu (CN) instead
2(K
3C
6H
5O
73C
6H
8O
7)
5Be main salt, citrate changes into and checking every day, adjusts once.
Embodiment five is electroplated special thick gold (electroforming)
The golden salt of former employing is main salt, per hour replenishes once golden salt, replenishes a citrate every day.Use citric acid gold salt KAu (CN) instead
2(K
3C
6H
5O
70.5C
6H
8O
7)
0.3Be main salt, citrate once changes per three days into and replenishes once by replenishing every day.
Claims (1)
1, a kind of for gold-plated citric acid gold salt, in acid and neutral gold plating technology, adopt citric acid gold salt to substitute dicyan network potassium aurate, it is characterized in that: described citric acid gold salt is the hybrid junctions crystal of dicyan network aurate and citric acid acid salt, and its chemical composition is MAu (CN)
2(M
3C
6H
5O
7K
1C
6H
8O
7) k
2, M represents monovalent cation K in the formula
+, Na
+, NH
4 +In a kind of or its combination, MAu (CN)
2Be dicyan network aurate; M
3C
6H
5O
7K
1C
6H
8O
7Being citric acid acid salt, is by citric acid C
6H
8O
7With citrate M
3C
6H
5O
7Mix k
1Be the molar ratio 0≤k of the two
1≤ 5; K
2Molar ratio 0.3≤k for citric acid acid salt and dicyan network aurate
2≤ 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610134865 CN1995472A (en) | 2006-12-19 | 2006-12-19 | Gold citrate for glod plating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610134865 CN1995472A (en) | 2006-12-19 | 2006-12-19 | Gold citrate for glod plating |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1995472A true CN1995472A (en) | 2007-07-11 |
Family
ID=38250673
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200610134865 Pending CN1995472A (en) | 2006-12-19 | 2006-12-19 | Gold citrate for glod plating |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1995472A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101781784A (en) * | 2010-02-10 | 2010-07-21 | 张东山 | Gold potassium citrate for gold plating and preparation method thereof |
| CN101172946B (en) * | 2007-11-20 | 2011-02-16 | 三门峡市恒生生化技术有限公司 | Gold potassium lemon acid for gold plating and method for producing the same |
| CN102162111A (en) * | 2011-03-14 | 2011-08-24 | 张东山 | Preparation method of potassium gold citrate for gold plating |
| CN115160126A (en) * | 2022-08-16 | 2022-10-11 | 李婧 | Preparation method of gold potassium citrate without free cyanogen |
-
2006
- 2006-12-19 CN CN 200610134865 patent/CN1995472A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101172946B (en) * | 2007-11-20 | 2011-02-16 | 三门峡市恒生生化技术有限公司 | Gold potassium lemon acid for gold plating and method for producing the same |
| CN101781784A (en) * | 2010-02-10 | 2010-07-21 | 张东山 | Gold potassium citrate for gold plating and preparation method thereof |
| CN102162111A (en) * | 2011-03-14 | 2011-08-24 | 张东山 | Preparation method of potassium gold citrate for gold plating |
| CN115160126A (en) * | 2022-08-16 | 2022-10-11 | 李婧 | Preparation method of gold potassium citrate without free cyanogen |
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| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
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| C12 | Rejection of a patent application after its publication | ||
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Open date: 20070711 |