WO2010102516A1 - Method of manufacturing hard gold jewellery - Google Patents

Method of manufacturing hard gold jewellery Download PDF

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Publication number
WO2010102516A1
WO2010102516A1 PCT/CN2010/000298 CN2010000298W WO2010102516A1 WO 2010102516 A1 WO2010102516 A1 WO 2010102516A1 CN 2010000298 W CN2010000298 W CN 2010000298W WO 2010102516 A1 WO2010102516 A1 WO 2010102516A1
Authority
WO
WIPO (PCT)
Prior art keywords
mandrel
gold
layer
electroplating
gold layer
Prior art date
Application number
PCT/CN2010/000298
Other languages
French (fr)
Inventor
Sam L. S. Chong
Original Assignee
Pino Aliprandini (Hk) Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pino Aliprandini (Hk) Limited filed Critical Pino Aliprandini (Hk) Limited
Publication of WO2010102516A1 publication Critical patent/WO2010102516A1/en

Links

Classifications

    • A—HUMAN NECESSITIES
    • A44—HABERDASHERY; JEWELLERY
    • A44C—PERSONAL ADORNMENTS, e.g. JEWELLERY; COINS
    • A44C27/00—Making jewellery or other personal adornments
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D1/00—Electroforming
    • C25D1/02—Tubes; Rings; Hollow bodies
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D1/00—Electroforming
    • C25D1/08—Perforated or foraminous objects, e.g. sieves
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/48—Electroplating: Baths therefor from solutions of gold
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/10—Electroplating with more than one layer of the same or of different metals
    • C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/48—After-treatment of electroplated surfaces
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/60—Electroplating characterised by the structure or texture of the layers
    • C25D5/605—Surface topography of the layers, e.g. rough, dendritic or nodular layers
    • C25D5/611—Smooth layers
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/627—Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance

Definitions

  • the present invention relates to the manufacture of gold jewellery.
  • the invention more particularly relates to an electroforming process for manufacturing hard 24 carat gold jewellery.
  • Pure gold jewellery produced by casting is quite soft with a hardness value of only about 40 Hv. Such soft gold jewellery is easily damaged in use.
  • Gold pieces can also be formed by electroforming in a gold potassium cyanide bath. Pieces made by this method are also relatively soft and as a result, the method is generally restricted to the production of ornamental pieces not to be worn.
  • a method of forming hard gold jewellery comprising: forming a mandrel of low melting point material ; electroplating a gold layer over the mandrel; electroplating a copper layer over the gold layer; forming holes through the electroplated layers to the mandrel ; and melting the mandrel and causing it to escape through one or more of the holes .
  • the method further comprises the step of electroplating a nickel layer over the copper layer before the holes are formed.
  • the mandrel is formed of alloy including tin and/or bismuth .
  • the alloy has a melting temperature of about 150 0 C.
  • the mandrel is formed of wax
  • the method further comprises the step of electroplating a primary copper layer on the mandrel, and the gold layer is electroplated over the primary copper layer.
  • the escape of molten mandrel material is assisted by vibration and/or centrifugation.
  • the gold layer is electroplated in a non- cyanide bath comprising a gold sulphite complex.
  • the bath contains organic and inorganic additives to make the gold layer smooth, bright and hard.
  • the melting step takes place at about 200 0 C.
  • the method further comprises the step of dipping the formed gold layer into nitric acid to remove any remaining alloy .
  • the method further comprises the steps of soldering, sand blasting and polishing.
  • Fig. 1 is a schematic illustration of a mandrel-forming step
  • Fig. 2 is a schematic illustration of a pre-treatment step
  • Fig. 3 is a schematic illustration of a primary copper plating step
  • Fig. 4 is a schematic illustration of a 24 carat hard gold electroforming step
  • Fig. 5 is a schematic illustration of a further copper plating step
  • Fig. 6 is a schematic illustration of a nickel plating step
  • Fig. 7 is a schematic illustration of a mandrel melting step
  • Fig. 8 is a schematic illustration of an alloy dissolving step
  • Fig. 9 is a schematic illustration of an emptied hollow gold piece . Description of the Preferred Embodiment
  • Mandrels 10 of low melting point alloy are produced by spin casting in silicon rubber moulds 11 as depicted in Fig . 1.
  • the mandrels 10 are placed in a tumbler to remove spurs and any parting lines . Further grinding and polishing may be required to smooth the surface of the mandrels .
  • wax can be used to form the mandrels. If wax is used, it should be removed before placing the mandrels into the electroforming baths as the bath temperature is typically higher than the melting point of the wax .
  • the mandrels 10 are then attached to jigs 20 of a plating rack. They are cleaned in an electrolytic/ultrasonic cleaning bath 12 as shown in Fig. 2.
  • a thin copper layer is formed in the step shown in Fig . 3.
  • the clean mandrels 10 are transferred to a copper plating bath 13 where a 100 micron (typical thickness) copper layer is electroplated upon the surface of the mandrels 10.
  • This copper layer should be bright and smooth so that the gold electroformed layer will also be bright and smooth. Also this copper layer serves as a barrier layer to the gold and the low melting point alloy. If wax is used to form the mandrel , the wax should be emptied leaving a copper shell for further electroforming.
  • the copper-plated wax mandrels , or low melting point alloy mandrels 10 as the case may be, are placed into the gold electroforming bath 14 (Fig. 4) which contains a non-cyanide solution comprising a gold sulphite complex.
  • the bath 14 contains suitable organic and inorganic additives to make the gold layer smooth, bright and hard.
  • the gold sulphite complex e.g. K 3 Au(SOa) 2
  • alkaline metals such as potassium and sodium or ammonium
  • the organic additives are used to stabilize the gold sulphite complex - preventing it from self-reduction to metallic gold.
  • the electroforming process typically takes about five hours depending on the required gold thickness .
  • the deposition rate is typically about 15 to 20 microns per hour.
  • a second copper layer is electroplated over the gold layer in the copper plating bath 13. This is shown in Fig. 5. This copper layer is typically about 50 microns thick and is plated onto the gold layer to form a protective layer.
  • a thin nickel layer (typically about 5 microns) is electroplated over the copper layer in a nickel plating bath 15.
  • the nickel layer prevents the gold layer from "dissolving" , in which case the low melting point alloy could stick to the gold or copper surface during subsequent melting out of the low melting point alloy.
  • electroplating can be performed by conventional means in which the mandrel and associated layers are connected electrically with the jig 20 and together form a cathode connected to a direct current power source.
  • An anode is connected to the positive terminal of the direct current power source and is immersed in the electroplating bath solution.
  • the pieces 19 are then removed from the jig 20 and two or more holes are drilled in suitable positions through the various electroplated layers to the mandrel core .
  • the pieces 19 are then placed in an oven 16 (Fig. 7) where they are heated to about 200 0 C. Most of the molten low melting point alloy will exude 17 through the holes .
  • Vibration and/or centrifugation can be employed to assist the removal of the molten material .
  • Any remaining low melting point alloy can be removed by immersion of the pieces 19 in a bath 18 of diluted nitric acid (Fig. 8) .
  • the sandwiched copper layers and the nickel layer are dissolved by the nitric acid together with any low melting point alloy so that only a pure gold electroformed shell remains .
  • the pieces 19 are pure gold with assay of more than 99.9%.
  • the pieces 19 can now proceed to soldering, sand blasting and polishing to become jewellery pieces.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Adornments (AREA)
  • Electroplating Methods And Accessories (AREA)
  • Display Devices Of Pinball Game Machines (AREA)

Abstract

A method of forming hard gold jewellery includes forming a mandrel of low melting point material, electroplating a gold layer over the mandrel, electroplating a copper layer over the gold layer, forming holes through the electroplated layers to the mandrel, and melting the mandrel and causing it to escape through one or more of the holes.

Description

Method of Manufacturing Hard Gold Jewellery
Background of the Invention
The present invention relates to the manufacture of gold jewellery. The invention more particularly relates to an electroforming process for manufacturing hard 24 carat gold jewellery.
Pure gold jewellery produced by casting is quite soft with a hardness value of only about 40 Hv. Such soft gold jewellery is easily damaged in use.
Gold pieces can also be formed by electroforming in a gold potassium cyanide bath. Pieces made by this method are also relatively soft and as a result, the method is generally restricted to the production of ornamental pieces not to be worn.
Objects of the Invention
It is an object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages and/or more generally to provide an improved method of forming hard gold jewellery items suitable for every day use. Disclosure of the Invention
There is disclosed herein a method of forming hard gold jewellery, comprising: forming a mandrel of low melting point material ; electroplating a gold layer over the mandrel; electroplating a copper layer over the gold layer; forming holes through the electroplated layers to the mandrel ; and melting the mandrel and causing it to escape through one or more of the holes .
Preferably, the method further comprises the step of electroplating a nickel layer over the copper layer before the holes are formed.
Preferably, the mandrel is formed of alloy including tin and/or bismuth .
Preferably, the alloy has a melting temperature of about 1500C.
Preferably, the mandrel is formed of wax, and the method further comprises the step of electroplating a primary copper layer on the mandrel, and the gold layer is electroplated over the primary copper layer.
Preferably, the escape of molten mandrel material is assisted by vibration and/or centrifugation.
Preferably, the gold layer is electroplated in a non- cyanide bath comprising a gold sulphite complex.
Preferably, the bath contains organic and inorganic additives to make the gold layer smooth, bright and hard.
Preferably, the melting step takes place at about 2000C.
Preferably, the method further comprises the step of dipping the formed gold layer into nitric acid to remove any remaining alloy .
Preferably, the method further comprises the steps of soldering, sand blasting and polishing.
By virtue of using a gold sulphite complex in the electroforming bath together with proper additives, 24 carat gold jewellery pieces can be formed with sufficient hardness to be worn daily .
Brief Description of the Drawings
A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings , wherein : - A -
Fig. 1 is a schematic illustration of a mandrel-forming step;
Fig. 2 is a schematic illustration of a pre-treatment step;
Fig. 3 is a schematic illustration of a primary copper plating step;
Fig. 4 is a schematic illustration of a 24 carat hard gold electroforming step;
Fig. 5 is a schematic illustration of a further copper plating step;
Fig. 6 is a schematic illustration of a nickel plating step;
Fig. 7 is a schematic illustration of a mandrel melting step;
Fig. 8 is a schematic illustration of an alloy dissolving step; and
Fig. 9 is a schematic illustration of an emptied hollow gold piece . Description of the Preferred Embodiment
In the accompanying drawings there is depicted schematically the various steps in forming a hollow piece of gold suitable for use in jewellery. The method typically results in gold jewellery having a purity higher than 99.9% with a micro-hardness high than 100 Hv.
Mandrels 10 of low melting point alloy are produced by spin casting in silicon rubber moulds 11 as depicted in Fig . 1.
After casting, the mandrels 10 are placed in a tumbler to remove spurs and any parting lines . Further grinding and polishing may be required to smooth the surface of the mandrels .
As an alternative to low melting point alloy, wax can be used to form the mandrels. If wax is used, it should be removed before placing the mandrels into the electroforming baths as the bath temperature is typically higher than the melting point of the wax .
The mandrels 10 are then attached to jigs 20 of a plating rack. They are cleaned in an electrolytic/ultrasonic cleaning bath 12 as shown in Fig. 2.
If wax is used to form the mandrels 10, a thin copper layer is formed in the step shown in Fig . 3. The clean mandrels 10 are transferred to a copper plating bath 13 where a 100 micron (typical thickness) copper layer is electroplated upon the surface of the mandrels 10. This copper layer should be bright and smooth so that the gold electroformed layer will also be bright and smooth. Also this copper layer serves as a barrier layer to the gold and the low melting point alloy. If wax is used to form the mandrel , the wax should be emptied leaving a copper shell for further electroforming.
The copper-plated wax mandrels , or low melting point alloy mandrels 10 as the case may be, are placed into the gold electroforming bath 14 (Fig. 4) which contains a non-cyanide solution comprising a gold sulphite complex. The bath 14 contains suitable organic and inorganic additives to make the gold layer smooth, bright and hard.
Typically, the gold sulphite complex (e.g. K3Au(SOa)2) with alkaline metals such as potassium and sodium or ammonium is used to make up the electroforming bath. The organic additives are used to stabilize the gold sulphite complex - preventing it from self-reduction to metallic gold.
The electroforming process typically takes about five hours depending on the required gold thickness . The deposition rate is typically about 15 to 20 microns per hour. After electroforming the gold layer, a second copper layer is electroplated over the gold layer in the copper plating bath 13. This is shown in Fig. 5. This copper layer is typically about 50 microns thick and is plated onto the gold layer to form a protective layer.
Following this step and as shown in Fig. 6, a thin nickel layer (typically about 5 microns) is electroplated over the copper layer in a nickel plating bath 15. The nickel layer prevents the gold layer from "dissolving" , in which case the low melting point alloy could stick to the gold or copper surface during subsequent melting out of the low melting point alloy.
In each of the electroplating steps described above, electroplating can be performed by conventional means in which the mandrel and associated layers are connected electrically with the jig 20 and together form a cathode connected to a direct current power source. An anode is connected to the positive terminal of the direct current power source and is immersed in the electroplating bath solution.
The pieces 19 are then removed from the jig 20 and two or more holes are drilled in suitable positions through the various electroplated layers to the mandrel core . The pieces 19 are then placed in an oven 16 (Fig. 7) where they are heated to about 2000C. Most of the molten low melting point alloy will exude 17 through the holes .
Vibration and/or centrifugation can be employed to assist the removal of the molten material .
Any remaining low melting point alloy can be removed by immersion of the pieces 19 in a bath 18 of diluted nitric acid (Fig. 8) . The sandwiched copper layers and the nickel layer are dissolved by the nitric acid together with any low melting point alloy so that only a pure gold electroformed shell remains .
After all the low melting point alloy is removed, the pieces 19 are pure gold with assay of more than 99.9%.
The pieces 19 can now proceed to soldering, sand blasting and polishing to become jewellery pieces.

Claims

CIAIMS :
1. A method of forming hard gold jewellery, comprising: forming a mandrel of low melting point material ; electroplating a gold layer over the mandrel; electroplating a copper layer over the gold layer; forming holes through the electroplated layers to the mandrel ; and melting the mandrel and causing it to escape through one or more of the holes .
2. The method of Claim 1 , further comprising the step of electroplating a nickel layer over the copper layer before the holes are formed.
3. The method of Claim 1 , wherein the mandrel is formed of alloy including tin and/or bismuth.
4. The method of Claim 3, wherein the alloy has a melting temperature of about 1500C.
5. The method of Claim 1 , wherein the mandrel is formed of wax, and further comprising the step of: electroplating a primary copper layer on the mandrel; and wherein : the gold layer is electroplated over the primary copper layer.
6. The method of Claim 1 , wherein escape of the molten mandrel is assisted by vibration and/or centrifugation .
7. The method of Claim 1 , wherein the gold layer is electroplated in a non-cyanide bath comprising a gold sulphite complex.
8. The method of Claim 7 , wherein the bath contains organic and inorganic additives to make the gold layer smooth, bright and hard.
9. The method of Claim 1 , wherein the melting step takes place at about 2000C.
10. The method of Claim 3, followed by dipping the formed gold layer into nitric acid to remove any remaining alloy .
11. The method of Claim 1, including the further steps of soldering, sand blasting and polishing.
PCT/CN2010/000298 2009-03-11 2010-03-11 Method of manufacturing hard gold jewellery WO2010102516A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN200910127120.7 2009-03-11
CN200910127120A CN101828799A (en) 2009-03-11 2009-03-11 Method for manufacturing hard gold jewelry

Publications (1)

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WO2010102516A1 true WO2010102516A1 (en) 2010-09-16

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITAR20130022A1 (en) * 2013-06-24 2014-12-25 Raika S R L PROCEDURE FOR THE CREATION OF SWEATERS FOR LIGHT ORNAMENTAL ITEMS, PARTICULARLY FOR THE CONSTRUCTION OF CHAINS AND THE LIKE.
ITUB20154997A1 (en) * 2015-10-28 2017-04-28 Raika S R L PROCEDURE FOR THE REALIZATION OF LIGHT ORNAMENTAL ITEMS, PARTICULARLY FOR THE REALIZATION OF CHAINS AND THE LIKE.
IT201600105719A1 (en) * 2016-10-20 2018-04-20 Gold Esprit S R L ARTICLE OF ELECTRIC WORKSHOPS, SILVERWARE AND JEWELERY FROM ELECTROFORMING AND ITS REALIZATION PROCEDURE
CN113699563A (en) * 2021-08-24 2021-11-26 深圳市联合蓝海黄金材料科技股份有限公司 Production method of hard gold round ball

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CN102934870A (en) * 2012-06-05 2013-02-20 时兴伟 Process method for manufacturing hollow finger ring with noble metal
CN104544801B (en) * 2014-08-20 2015-11-18 深圳市联合蓝海科技开发有限公司 A kind of preparation method of gold ornament
CN104593831A (en) * 2015-01-26 2015-05-06 黄盛平 Method for producing watch by virtue of 3D noble metal technique
CN105193018A (en) * 2015-09-10 2015-12-30 深圳市金百泰珠宝实业有限公司 Manufacturing process of gold bracelet and gold bracelet
CN107028305A (en) * 2016-11-30 2017-08-11 陈哲 A kind of processing method of hollow gold ornaments
CN106637307B (en) * 2017-01-04 2019-01-01 中国地质大学（武汉） A kind of additive for gold without cyanogen electroforming process
CN110791758A (en) * 2019-11-27 2020-02-14 衡阳市晋宏精细化工有限公司 Portable jewelry gilding device
CN111761313B (en) * 2020-07-10 2021-10-26 中国工程物理研究院激光聚变研究中心 Method for manufacturing hollow double-layer gold cone

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4343684A (en) * 1980-12-19 1982-08-10 Stanley Lechtzin Method of electroforming and product
US4464231A (en) * 1980-10-22 1984-08-07 Dover Findings Inc. Process for fabricating miniature hollow gold spheres
JPH08218192A (en) * 1995-02-14 1996-08-27 Yasui Boeki Kk Production of hollow electroforming products by noble metal
US6212745B1 (en) * 1996-10-09 2001-04-10 Pgcm Conception, Societe Civile D'inventeurs Method for setting stones in the surface of a jewel produced by electroforming
CN101255579A (en) * 2007-02-26 2008-09-03 深圳市百泰珠宝首饰有限公司 Method for manufacturing hollow out multiple-layer gold ornaments

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4464231A (en) * 1980-10-22 1984-08-07 Dover Findings Inc. Process for fabricating miniature hollow gold spheres
US4343684A (en) * 1980-12-19 1982-08-10 Stanley Lechtzin Method of electroforming and product
JPH08218192A (en) * 1995-02-14 1996-08-27 Yasui Boeki Kk Production of hollow electroforming products by noble metal
US6212745B1 (en) * 1996-10-09 2001-04-10 Pgcm Conception, Societe Civile D'inventeurs Method for setting stones in the surface of a jewel produced by electroforming
CN101255579A (en) * 2007-02-26 2008-09-03 深圳市百泰珠宝首饰有限公司 Method for manufacturing hollow out multiple-layer gold ornaments

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITAR20130022A1 (en) * 2013-06-24 2014-12-25 Raika S R L PROCEDURE FOR THE CREATION OF SWEATERS FOR LIGHT ORNAMENTAL ITEMS, PARTICULARLY FOR THE CONSTRUCTION OF CHAINS AND THE LIKE.
ITUB20154997A1 (en) * 2015-10-28 2017-04-28 Raika S R L PROCEDURE FOR THE REALIZATION OF LIGHT ORNAMENTAL ITEMS, PARTICULARLY FOR THE REALIZATION OF CHAINS AND THE LIKE.
IT201600105719A1 (en) * 2016-10-20 2018-04-20 Gold Esprit S R L ARTICLE OF ELECTRIC WORKSHOPS, SILVERWARE AND JEWELERY FROM ELECTROFORMING AND ITS REALIZATION PROCEDURE
CN113699563A (en) * 2021-08-24 2021-11-26 深圳市联合蓝海黄金材料科技股份有限公司 Production method of hard gold round ball
CN113699563B (en) * 2021-08-24 2023-01-03 深圳市联合蓝海黄金材料科技股份有限公司 Production method of hard gold round ball

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