WO2021066761A1 - A copper wire with increased conductivity by electrophoretic storage method using graphene conductivity and a method for production - Google Patents
A copper wire with increased conductivity by electrophoretic storage method using graphene conductivity and a method for production Download PDFInfo
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- WO2021066761A1 WO2021066761A1 PCT/TR2019/050824 TR2019050824W WO2021066761A1 WO 2021066761 A1 WO2021066761 A1 WO 2021066761A1 TR 2019050824 W TR2019050824 W TR 2019050824W WO 2021066761 A1 WO2021066761 A1 WO 2021066761A1
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- copper
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- suspension
- charged
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
- H01B1/026—Alloys based on copper
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D13/00—Electrophoretic coating characterised by the process
- C25D13/02—Electrophoretic coating characterised by the process with inorganic material
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D13/00—Electrophoretic coating characterised by the process
- C25D13/12—Electrophoretic coating characterised by the process characterised by the article coated
- C25D13/16—Wires; Strips; Foils
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D13/00—Electrophoretic coating characterised by the process
- C25D13/22—Servicing or operating apparatus or multistep processes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/04—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of carbon-silicon compounds, carbon or silicon
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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)
- Inorganic Chemistry (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
A copper coating method for reducing resistance losses and increasing energy efficiency in conductors and devices where copper is used as conductor, characterized in that; coating of charged graphene oxide particles (5) in the suspension by the electrophoretic storage method, which directs them to the conductive electrodes on the copper surface (wire surface) (7) under the effect of the electric field formed between the electrically charged conductor electrodes of a certain amount.
Description
A Copper Wire with Increased Conductivity by Electrophoretic Storage Method Using Graphene Conductivity and A Method for Production
Technical Field
The invention relates to a copper coating method for reducing resistance losses in conductors and devices where copper is used as a conductor and to improve energy efficiency.
Prior Art
Graphene is defined as a planar carbon material formed by bonding sp2 hybrid carbon atoms with a thickness of 1 atom. Each carbon atom in the graphene crystal contributes to the formation of a delocalized electron network with its p electrons. After graphite was first isolated from graphite by Geim and Novoselov in 2004 using micromechanical separation method using sticky tape, the studies on graphene increased rapidly. Geim and Novoselov received the Nobel Prize in 2010 for their work on graphene.
The planar delocalized electron network of the graphene permits the movement of electrons in the structure at relativistic speeds. Due to this structure, graphene has very high electrical and thermal conductivity, high optical permeability, high mechanical strength and flexibility and very high theoretical specific surface area (2630 m2 / g). In addition, high chemical resistance and non toxic properties have been reported. The combination of one or more of these unusual features has made graphene the material to be used in new super-featured technologies that can replace existing technologies. For example, optical
permeability, flexibility and conductivity can be combined to produce flexible electronics. In addition, graphene, field-effect transistors, touch screens, energy storage and conversion (lithium-ion batteries and fuel cells, electrochemical supercapacitors, dye-sensitive solar cells) and in the field of health (cell imaging, photochemotherapy, drug release, biosensors) potential. However, barriers to the production of large quantities of cheap, pure and flawless graphene limit these applications.
In the present technique, it is desirable to increase the electrical conductivity of copper by graphene coating. There are many different methods for coating. The main methods used are simple immersion method and electroinduction method.
The simple immersion method is carried out by simply immersing the copper to be plated in the graphene-containing suspension for 30 seconds. There is no complete coating on the copper plate as a result of the process. Graphical coating of graphene coated copper plate by simple dipping method is shown in figure-2.
Electro-reduction method, the copper plate to be coated with graphene, dipped in graphene suspension and applied to the -5 V potential of graphene on the copper plate is reduced by coating. There is no complete coating on the copper plate as a result of the process. Graphical deposition of copper plate with electro reduction method is shown in figure- 3
Purpose of The Invention
Aim of the invention; using the high electrical conductivity of graphene is to reduce the losses caused by resistance in transmission lines and devices where copper is used as a conductor and to increase energy efficiency.
Another purpose of the invention is; to be used as a superconductor in electronic devices and to reduce the resistance caused by heating in electronic devices.
Another object of the invention is; graphene coated copper lines are used to prevent electricity losses and contribute to the national economy.
Another main aim of the invention is to provide superconductor wire in electronic devices for hardware such as motherboards, video cards, etc. to increase memory capacity, processor speed and system efficiency in general.
The method developed to achieve the said objectives; is the process of coatting copper by electrophoretic storage method.
Description of the Figures
Figure 1 is the front view of the uncoated copper plate.
Figure-2 is the front view of the copper plate coated with simple dipping method.
Figure-3 is the front view of the copper plate coated with electro-reduction method.
Figure-4 is the front view of the copper plate coated with electrophoretic storage method.
Figure-5 is the schematic view of the electrophoretic storage method.
Figure-6 is the cross-sectional view of the copper wire (7) coated with electrophoretic storage method.
Figure-7 is the graph of the current- voltage data at lOnm depth with “four point probe” device for uncoated copper.
Figure-8 is the graph of the current- voltage data at -1.105nm depth with “four point probe” device for uncoated copper.
Figure-9 Graph of the current- voltage data at -lOnm depth with “ four point probe ’’device for copper coated with graphene.
Figure- 10 Graph of the current- voltage data at 1.105m depth with “four point probe” device for copper coated with graphene.
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(1) Power supply
(2) Anode
(3) Cathode
(4) Glass cabinet
(5) Charged graphene oxide particles
(6) Stable graphene suspension
(7) Copper surface (wire)
(8) Graphene coating
(9) Plastic coating
Detailed Description of the Invention
The invention relates to a copper coating method for reducing resistance losses in conductors and devices where copper is used as a conductor and to improve energy efficiency.
Electrophoretic storage method; It is an electrochemical method which directs the charg graphene oxide particles (5) in the suspension to the conductive electrodes to hold onto the copper surface (7) under the effect of electric field formed between a certain amount of electrical potential and charged conductive electrodes. Accumulation of matter in the electrode is caused by particle coagulation.
Advantages of electrophoretic storage method; technique; It is simple, it can be applied to combinations of a wide range of materials and is suitable for large scale production. In order to apply the electrophoretic storage method, it is necessary to first prepare stable suspensions of graphene (6) of charged graphene oxide particles (5) of the material to be coated in a suitable solvent. The beaker contains 100 ml of suspension, 50 mg of graphene, 10 ml of isopropyl alcohol, 90 ml of water and at least 50 mg of salt. Graphene, isoprofile alcohol, water and salt ratios used in the mixture can be used in varying amounts for alcohol homogenization. Suitable materials include isopropyl alcohol and water.
In the system according to the invention, certain amounts of graphene are mixed with isopropyl alcohol and then sonication process is provided to form homogeneous and stable graphene suspensions (6). Further, Mg (N03) 2 salt is added to the prepared suspension. The addition of magnesium (mg) salt is used small to make the graphene oxide positively charged. Said salt is added to the mixture dissolved in water. The steps of forming the mixture may vary. After the mixture is prepared, homogenization is performed by sonication process.
After the prepared suspension is filled into the glass cabinet (4) where the electrophoretic storage method process will be carried out, the apparatus given in Figure 5, which uses copper plate to be coated as cathode (3) and anode (2), is installed. Using the power supply (1), 30 V potentials are applied for 10 minutes and electrophoretic storage method treatment is performed. Variations in the given values may cause the coating thickness to change and the efficiency to increase or decrease accordingly. Both surfaces (anode and cathode) were used as copper. Since the important part is that the coating takes place on the anode, the cathode can be changed but it is more appropriate to use copper in terms of conductivity.
The experimental apparatus used in the electrophoretic storage method process and the graphene coated copper surface (wire) (7) obtained is shown in Figure-4. It is evident that copper surfaces (plate) coated with electrophoretic storage method and baked at 150 ° C are coated homogeneously with graphene. The baking process can be carried out at the desired temperature until drying is allowed to evaporate the solvent. The electrical conductivity measurements of copper wires (7) (plates) coated with electrophoretic storage method were compared with uncoated copper surface (wire) (7). Current- Voltage data obtained from different depths with “four point probe” device for uncoated copper wire (7) are shown in Figure-7 and Figure- 8. The current-voltage data obtained from different depths with the “four point probe” device for copper coated with graphene are shown in figure-9 and figure- 10 below.
Resistance (R) values of the samples were calculated from the slope of the current-voltage graphs according to Ohm's Law. Using the resistance data, the conductivity (L) values of the samples were calculated according to L = 1 / R formula. The calculated R and L values are given in Table- 1.
Table 1. Resistance and calculated conductivity values measured from different depths of graphene coated and uncoated copper sheets
With the invention, the electrical conductivity at a depth of 10 nm is about 10000 times higher than that of pure copper. According to the law of currents, the current prefers low resistance path. As a result, a significant increase in conductivity at a depth of lOnm significantly increases the conductivity of the entire copper plate. If industrial production can be made, the energy loss due to heating caused by resistance in electrical lines and the amount of copper used can be reduced. In said electrophoretic storage method, the copper surface (7) is coated at 30 V potential for 10 minutes and baked at 150 ° C. In alternative embodiments of the invention, baking may be carried out at 100-200 ° C. Therefore, the method has the property of being applicable on an industrial scale. Reducing the tension used in graphene coating in the system of the invention increases the time, increasing the voltage decreases the time. Productivity varies according to voltage and application time.
Invention; it is a graphene coating (8) method on copper surface (wire) (7) which can be found in various forms such as wire and plate by electrophoretic storage method. After the copper wire (7) is coated with a suspension containing graphene, a plastic coating (9) can be made on the copper wire (7). With the plastic coating (9), both copper wire (7) and graphene coating (8) are protected from external factors. Variability of the numerical data in the coating stages may change the amount of coating and the results, but various variations do not cause the method to change. After yield, uniform values (V, time, firing temperature, distance) and constant materials (graphene quality) can be used to produce uniform ( not non-uniform in every other productions, constant yield) production.
Stable graphene containing power supply (1), anode (2), cathode (3), glass cabinet (4), charged graphene oxide particles (5) for conducting the graphene coating (8) of the copper wire (7) of the present invention by electrophoretic storage method suspension (6) is used. In alternative embodiments of the invention, instead of the glass cabinet (4) cabinets of other material may be used.
The invention is a copper coating method for reducing resistance losses and increasing energy efficiency in conductors and devices where copper is used as conductor, characterized in that; coating of charged graphene oxide particles (5) in the suspension by the electrophoretic storage method, which directs them to the conductive electrodes on the copper surface (wire surface) (7) under the effect of the electric field formed between the electrically charged conductor electrodes of a certain amount.
The invention is a method characterized in that; it comprises following process steps,
Preparation of stable graphene suspensions (6) of charged graphene oxide particles (5) of the material to be coated charged in water or a suitable solvent containing only water with isopropyl alcohol added, Adding salt Mg (N03) 2 and / or any salt containing +2 cations to the prepared suspension,
Mixing certain amounts of graphene with isopropyl alcohol, if not added in the first process step,
The process of sonication for the formation of homogeneous and stable graphene suspensions (6).
The suspension characterized in that; each 100 ml suspension contains 50 mg graphene, 10 ml isopropyl alcohol, 90 ml water and at least 50 mg salt.
The invention is a method characterized in that; after the filling of said suspension into the glass cabinet (4) in which the electrophoretic storage process is carried out, copper plate to be coated is used both as cathode (3) and anode (2).
The invention is a method characterized in that; applying of at least 30 V potentials for 10 minutes using the power supply (1) while performing electrophoretic storage. The invention is a method characterized in that; baking the copper plate at
100-200°C after the electrophoretic storage method is completed.
The invention is a method characterized in that; it comprises, a power supply (1), anode (negatively charged coat) (2), cathode (positively charged coat) (3), the glass cabinet (4), and the stable graphene suspension (6) including charged graphene oxide particles (5) which enable said method to be performed.
The invention is a method characterized in that; the graphene coating (8) is carried out via anode.
The invention is a copper coating method for reducing resistance losses and increasing energy efficiency in conductors and devices where copper is used as conductor, characterized in that; it comprises a copper wire (7) that coating of charged graphene oxide particles (5) in the suspension by the electrophoretic storage method, which directs them to the conductive electrodes on the copper surface (wire surface) (7) under the effect of the electric field formed between the electrically charged conductor electrodes of a certain amount.
Claims
1. A copper coating method for reducing resistance losses and increasing energy efficiency in conductors and devices where copper is used as conductor, characterized in that; coating of charged graphene oxide particles (5) in the suspension by the electrophoretic storage method, which directs them to the conductive electrodes on the copper surface (wire surface) (7) under the effect of the electric field formed between the electrically charged conductor electrodes of a certain amount.
2. A method mentioned in claim 1, characterized in that; it comprises following process steps,
Preparation of stable graphene suspensions (6) of charged graphene oxide particles (5) of the material to be coated charged in water or a suitable solvent containing only water with isopropyl alcohol added, Adding salt Mg (N03) 2 and / or any salt containing +2 cations to the prepared suspension,
Mixing certain amounts of graphene with isopropyl alcohol, if not added in the first process step,
The process of sonication for the formation of homogeneous and stable graphene suspensions (6).
3. The suspension mentioned in claim 1; each 100 ml suspension contains 50 mg graphene, 10 ml isopropyl alcohol, 90 ml water and at least 50 mg salt.
4. A method mentioned in either one of the claims stated above, characterized in that; after the filling of said suspension into the glass cabinet (4) in which the electrophoretic storage process is carried out, copper plate to be coated is used both as cathode (3) and anode (2).
5. A method mentioned in either one of the claims stated above, characterized in that; applying of at least 30 V potentials for 10 minutes using the power supply (1) while performing electrophoretic storage.
6. A method mentioned in either one of the claims stated above, characterized in that; baking the copper plate at 100-200°C after the electrophoretic storage method is completed.
7. A method mentioned in claim 1, characterized in that; it comprises, a power supply (1), anode (negatively charged coat) (2), cathode (positively charged coat) (3), the glass cabinet (4), and the stable graphene suspension (6) including charged graphene oxide particles (5) which enable said method to be performed.
8. A method mentioned in claim 1, characterized in that; the graphene coating (8) is carried out via anode.
9. A copper coating method for reducing resistance losses and increasing energy efficiency in conductors and devices where copper is used as conductor, characterized in that; it comprises a copper wire (7) that coating of charged graphene oxide particles (5) in the suspension by the electrophoretic storage method, which directs them to the conductive electrodes on the copper surface (wire surface) (7) under the effect of the electric field formed between the electrically charged conductor electrodes of a certain amount.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/TR2019/050824 WO2021066761A1 (en) | 2019-10-03 | 2019-10-03 | A copper wire with increased conductivity by electrophoretic storage method using graphene conductivity and a method for production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/TR2019/050824 WO2021066761A1 (en) | 2019-10-03 | 2019-10-03 | A copper wire with increased conductivity by electrophoretic storage method using graphene conductivity and a method for production |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114686944A (en) * | 2022-04-08 | 2022-07-01 | 北京科技大学 | Surface treatment method for reducing oxygen-free copper secondary electron yield |
| CN115074799A (en) * | 2022-07-21 | 2022-09-20 | 日铭电脑配件(上海)有限公司 | Anodic oxidation cathode plate and preparation method and application thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110227000A1 (en) * | 2010-03-19 | 2011-09-22 | Ruoff Rodney S | Electrophoretic deposition and reduction of graphene oxide to make graphene film coatings and electrode structures |
| US20130220530A1 (en) * | 2012-02-24 | 2013-08-29 | Kuanping Gong | Method of transferring graphene |
| WO2015041439A1 (en) * | 2013-09-23 | 2015-03-26 | 전자부품연구원 | Coaxial cable including graphene coating layer and manufacturing method therefor |
-
2019
- 2019-10-03 WO PCT/TR2019/050824 patent/WO2021066761A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110227000A1 (en) * | 2010-03-19 | 2011-09-22 | Ruoff Rodney S | Electrophoretic deposition and reduction of graphene oxide to make graphene film coatings and electrode structures |
| US20130220530A1 (en) * | 2012-02-24 | 2013-08-29 | Kuanping Gong | Method of transferring graphene |
| WO2015041439A1 (en) * | 2013-09-23 | 2015-03-26 | 전자부품연구원 | Coaxial cable including graphene coating layer and manufacturing method therefor |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114686944A (en) * | 2022-04-08 | 2022-07-01 | 北京科技大学 | Surface treatment method for reducing oxygen-free copper secondary electron yield |
| CN114686944B (en) * | 2022-04-08 | 2024-01-26 | 北京科技大学 | Surface treatment method for reducing secondary electron yield of oxygen-free copper |
| CN115074799A (en) * | 2022-07-21 | 2022-09-20 | 日铭电脑配件(上海)有限公司 | Anodic oxidation cathode plate and preparation method and application thereof |
| CN115074799B (en) * | 2022-07-21 | 2024-04-26 | 日铭电脑配件(上海)有限公司 | Anodic oxidation cathode plate and preparation method and application thereof |
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