JP2021107313A - Method for directly joining graphene-joined body formed by directly joining graphenes, to surface of base material or component - Google Patents

Abstract

To provide a method for joining a graphene-joined body directly to a surface of a base material or component, the graphene-joined body being formed by joining graphenes directly.SOLUTION: Within methanol, a graphene aggregate is produced from an aggregate of graphite particles, and then is separated into sheets of graphene. Subsequently, the sheets of graphene are laminated through a fluid, the viscosity of which is enhanced by mixing an organic compound having high viscosity with the methanol. Moreover, the graphene laminate is arranged on a surface of a base material or component, and then the methanol and the organic component are gasified, thereby compressing the graphene laminate. Accordingly, a graphene-joined body formed by joining the graphenes directly is joined directly to the base material and component.SELECTED DRAWING: Figure 1

Description

In the present invention, first, in methanol filled in a container, all the interlayer bonds of the basal plane made of graphite crystals forming graphite particles are broken, and the basal plane aggregate made of graphite crystals, that is, the aggregate of graphene. Is dispersed in methanol. Next, an organic compound dissolved in methanol and having a viscosity exceeding 30 times the viscosity of methanol is mixed with methanol to prepare a methanol solution having a viscosity exceeding 20 times the viscosity of methanol. Further, in a new container, a collection of graphene in which graphenes are superposed with each other is created on the bottom surface of the new container as the shape of the graphene conjugate via a methanol solution having an increased viscosity. After this, the graphene aggregate is taken out and placed on the surface of the base material or component to evenly compress the surface of the graphene aggregate. As a result, after the methanol and the organic compound are vaporized, the graphenes are directly bonded to each other, and the graphene that comes into contact with the surface of the base material or the component is directly bonded to the surface of the base material or the component, and the graphene is bonded to each other. The bonded body is bonded to the surface of the base material or the component.
The present invention is an application relating to an improvement of Japanese Patent Application No. 2019-107537 (filed on June 9, 1991), which was filed earlier.

In 2004, a physicist at the University of Manchester in the United Kingdom used cellophane tape to tear off a single crystallite from graphite, the basal plane, which two-dimensionally forms a network of hexagonal carbon atoms. For the first time, we succeeded in extracting a planar substance having the size of a carbon atom as the thickness. This new substance was called graphene. The 2010 Nobel Prize in Physics has been awarded for this research result.

Graphene is an extremely thin substance whose thickness corresponds to the size of a carbon atom, and is a completely new carbon material having almost no mass. For this reason, it has physical characteristics far from those of conventional substances, and is attracting attention as a material that can be applied to a wide range of applications.
For example, it is the thinnest material with a thickness of 0.332 nm. The surface area per unit mass is 3000 m ² / g, which is the largest surface area. Furthermore, with Young's modulus of 1020 GPa, it is most stretchable and bendable. In addition, it has a shear modulus of 440 GPa and is the toughest substance. Further, the thermal conductivity is 19.5 W / Cm, which corresponds to 4.5 times the thermal conductivity of silver, which has the highest thermal conductivity among metals. Moreover, the current density exceeds 1000 times that of copper. Furthermore, it has electrical conductivity that is only 23 times the specific resistance of copper. Further, the electron mobility is 15000 cm ² / volt / sec, which is an order of magnitude higher than ^{the mobility of silicone of 1400 cm 2 / volt / sec.} Further, it is a single crystal material having a melting point of more than 3000 ° C. and has extremely high heat resistance.

Graphene, on the other hand, is produced in a variety of ways. For example, the aforementioned professor at Manchenster University physically peeled graphene from graphite by hand. In this method, it is difficult to peel off a large amount of graphene in a short time, and the peeled material is not always a single layer of graphite crystals, that is, graphene.
Further, Patent Document 1 describes a method for producing graphene by thermally decomposing a single crystal of silicon carbide. That is, the silicon carbide is heated in an inert atmosphere to thermally decompose the surface. At this time, silicon having a relatively low sublimation temperature is preferentially sublimated, and graphene is produced by the remaining carbon. However, a single crystal of silicon carbide is a very expensive material. Further, silicon is sublimated at a high temperature exceeding 1600 ° C. and in an atmosphere having a high degree of vacuum, but if even a small amount of silicon remains, graphene is not produced as a residue after thermal decomposition. Therefore, the cost of producing a single crystal of silicon carbide and the thermal decomposition treatment of the single crystal becomes very expensive. In addition, producing a large amount of graphene is more expensive.
Further, Patent Document 2 describes a method for producing graphene by bringing a carbon-based substance into contact with a sheet-shaped single crystal graphitized metal catalyst and heat-treating it in a reducing atmosphere. However, this manufacturing method is not an inexpensive manufacturing method, and is not a manufacturing method having excellent mass productivity. First, the production cost of producing a single crystal graphitized metal catalyst is even higher than that of a single crystal of silicon carbide. Second, the method of contacting a single crystal graphitized metal catalyst with a carbon-based substance is inferior in mass productivity. Third, the method of reducing the graphitized metal catalyst in an atmosphere rich in nitrogen gas containing hydrogen gas at a high temperature exceeding 1000 ° C. increases the heat treatment cost. Producing large quantities of graphene is even more expensive.

None of the graphene production methods to date have been, first of all, a method of simultaneously producing a large amount of graphene by an inexpensive production method. Second, the graphene produced is not necessarily graphene. In other words, graphene is a single crystal material consisting of a collection of carbon atoms that two-dimensionally forms a network structure consisting of hexagons of carbon atoms. Graphene is not produced. Furthermore, since the graphene produced is extremely thin and extremely lightweight, it is extremely difficult to confirm that it is graphene.
Therefore, the present inventor has found a method in which all the graphene produced is complete graphene and a large amount of graphene is instantly produced by an extremely simple method (Patent Document 3). That is, it is composed of only a single crystal of graphite, the crystallization of graphite progresses 100%, and a mass of natural graphite crystal, which is the cheapest carbon material, is crushed, and a collection of graphite particles is collected from the crushed graphite crystal. A collection of scaly graphite particles or lump graphite particles obtained by purifying and selecting only the graphite particles is narrowed into the gap between the two parallel plate electrodes, an electric field is applied to the two parallel plate electrodes, and the electric field is applied. This is a method of simultaneously destroying all the interlayer bonds of the basal plane made of graphite crystals forming graphite particles to produce a large amount of the basal plane, that is, graphene. ^{According to this method, a collection of 1.62 × 10 13} graphenes can be obtained from only 1 g of scaly graphite particles or massive graphite particles.

JP-A-2015-110485 JP-A-2009-143799 Patent No. 6166860

As explained in paragraph 3, graphene has amazing physical properties that are completely different from conventional materials, so research and development of various parts and devices using graphene are being carried out. On the other hand, if graphene can be manufactured by an inexpensive manufacturing method, graphenes can be freely overlapped with each other, and the overlapping graphenes can be directly bonded to each other to produce a graphene conjugate consisting of a collection of graphenes, the area, thickness, and shape can be obtained. Graphene conjugates can be manufactured without any restrictions. Since this graphene conjugate directly bonds graphene to each other, it has properties close to those of graphene. Furthermore, if the graphene junction can be directly bonded to the base material or component, the base material or component can be imparted with properties similar to graphene, and since there are no restrictions on the area, thickness and shape of the graphene junction, the graphene junction is bonded. There are no restrictions on the base material or parts to be used.
On the other hand, a large amount of graphene can be instantly produced by the production method according to Patent Document 3, but a method for producing a graphene conjugate in which graphenes are directly bonded to each other has not been found from this group of graphenes. Further, graphene produced by simultaneously destroying the basal plane made of graphite crystals in graphite particles by applying an electric field in Patent Document 3 is easily scattered during and after production. Further, graphene is a flat surface having an extremely thin thickness and an extremely large aspect ratio, which is the ratio of the size of the basal plane to the thickness. Therefore, when producing a group of graphene according to Patent Document 3, graphenes overlap each other. Moreover, the number of overlapping graphenes is not constant. In addition, it is not easy to distinguish whether graphenes overlap each other, and it depends on the observation with an electron microscope. Furthermore, since the bonding force between the overlapping graphenes is weak, they can be easily separated at the overlapping parts. Therefore, unless the graphenes are firmly bonded to each other, the graphene bonded body cannot be formed.

In order to directly bond a graphene junction consisting of a group of graphenes directly bonded to each other to the surface of a base material or a part, a group of graphenes in which graphenes overlap must be placed on the surface of the base material or the part. Must be. However, graphene is a flat powder having an extremely small mass, an extremely thin thickness, and an extremely large aspect ratio. Therefore, if graphenes are freely overlapped with each other via a highly viscous liquid, the liquid is adsorbed on the graphenes with an adsorption force according to the viscosity, so that a collection of graphenes in which the graphenes overlap can be taken out from the container. Further, the graphene cluster can be arranged on the surface of the base material or the component without breaking the state in which the graphenes are overlapped with each other through the highly viscous liquid. Based on this idea, the present invention was reached.
However, there are the following five problems to be solved when the graphene bonded body in which graphenes are directly bonded to each other is directly bonded to the surface of the base material or the component.
The first challenge is to simultaneously destroy all of the interlayer bonds of the basal plane consisting of graphite crystals in the graphite particles in a liquid with low viscosity and low density to produce a basal plane aggregate, that is, a graphene aggregate. Find a way. This ensures that graphene does not scatter during and after graphene production. That is, the lower the viscosity of the liquid, the more difficult it is for the liquid to be adsorbed on graphene, and the lower the density, the easier it is for graphene to move in the liquid. Therefore, the graphene aggregate is dispersed in a liquid having low viscosity and low density. However, when all the interlayer bonds of the basal plane made of graphite crystals in the graphite particles are broken at the same time, some graphenes overlap with each other.
The second task is to find a way to separate the graphene aggregates into individual graphenes in the above liquid. In other words, separating each graphene into individual graphenes is a pretreatment for superimposing graphenes on top of each other via a liquid.
The third problem is to find a method of forming a group of graphene in which graphenes are freely overlapped with each other in a liquid having an increased viscosity as the shape of a graphene conjugate formed on the surface of a base material or a part. be.
The fourth task is to dispose the above-mentioned group of graphene on the surface of the base material or part, and to directly join the graphene to each other and to obtain the graphene that comes into contact with the surface of the base material or part of the base material or part. It is to find a method of joining a graphene bonded body, which is directly bonded to the surface and the graphenes are bonded to each other, to a base material or a component.
Graphene is a tough material having a breaking strength of 42 N / m, which is more than 100 times stronger than steel. Therefore, by utilizing this feature, a graphene bonded body in which graphenes are bonded to each other can be bonded to a base material or a component.
The fifth problem is that the means for solving the above four problems all consist of extremely simple processing, and general-purpose inexpensive materials are used. As a result, a graphene aggregate can be produced by an inexpensive method using an inexpensive graphite particle aggregate, and a graphene conjugate having no restrictions on the area, thickness, and shape can be produced by an inexpensive method as a base material having various shapes. Or it can be joined to the surface of a part. As a result, the properties of the graphene conjugate, which is close to the properties of graphene, can be imparted to the base material or component having various shapes, and a new product using graphene is realized.

The method of directly joining the graphene bonded body, which is directly bonded to each other, to the surface of the base material or parts, is
A collection of scaly graphite particles or a collection of massive graphite particles is flatly packed on the surface of one of the parallel plate electrodes forming an electrode pair consisting of two parallel plate electrodes, and the one parallel plate electrode is placed in a container. Immersed in packed methanol, the other parallel plate electrode is superposed on the one parallel plate electrode via the aggregate of scaly graphite particles or the aggregate of the massive graphite particles, and two parallel plates are superposed. An electrode pair composed of electrodes is immersed in the graphite, and then a DC potential difference is applied to the gap between the electrode pairs, whereby the magnitude of the potential difference is divided by the size of the gap between the electrode pairs. An electric field corresponding to is applied to the aggregate of the scaly graphite particles or the aggregate of the lump graphite particles, and the application of the electric field causes the basal plane made of graphite crystals forming the scaly graphite particles or the lump graphite particles. All of the interlayer bonds are simultaneously broken to form an aggregate of graphene composed of the basal plane in the gap between the electrode pairs, after which the gap between the electrode pairs is expanded and the electrode pair is tilted in the methanol. Further, vibrations in three directions of left-right, front-back, and up-down are repeatedly applied to the container to move the graphene aggregate into the methanol through the gap between the electrode pairs, and then the two parallel sheets are moved from the container in parallel. The flat plate electrode is taken out, and further, the homogenizer device is operated in the methanol in the container, and impact is repeatedly applied to the graphene aggregate via the graphite, and the graphene aggregates are collected one by one in the graphite. The homogenizer device is taken out from the container, and the homogenizer device is taken out from the container. The compound is mixed in the container in an amount such that the viscosity of methanol in the container becomes more than 20 times the viscosity, and the aggregate of the graphite separated into each graphite is the organic compound. Is dispersed in the solution dissolved in the methanol. After that, vibrations in three directions of left and right, front and back, and up and down are repeatedly applied to the container, and finally, vibrations in the up and down directions are applied to the graphenes via the solution. In the first step of superimposing the graphite and forming a collection of the overlapping graphene on the bottom surface of the container as the shape of the bottom surface.
A new container having the shape of a graphene junction in which graphenes are joined as the shape of the bottom surface is filled with a part of a collection of graphenes in which graphenes overlap each other via the solution, and the container is filled with left and right, front and back, and so on. The graphenes are repeatedly vibrated in three directions, up and down, and finally vibrated in the up and down direction to form a collection of graphene in which graphenes are overlapped with each other via the solution, as the shape of the bottom surface of the new container. The second step and
From the new container, a group of graphene in which graphenes are overlapped with each other is taken out through the solution, and the group of graphene is placed at a position where it is joined to the surface of a base material or a component, and further, the group of graphene is placed. A compression member having a shape is superposed on the surface of the graphene aggregate, after which the base material or the component is heated to the boiling point of the organic compound and the graphene aggregate is compressed by the compression member. As a result, the methanol and the organic compound are vaporized in order from the graphene aggregate, and the contact surfaces of the overlapping graphenes in the graphene aggregate are bonded to each other, and the surface of the base material or the component is formed. The graphene in contact with the base material or the surface of the component is bonded to the surface of the base material or the component, and the graphene junction composed of a collection of graphene bonded to the graphene is bonded to the surface of the base material or the component. Process and
A fourth method in which an impact is applied to a side surface forming the thickness of the compressed member with respect to the compressed member obtained by compressing a collection of graphene, and the compressed member is bonded to the surface of the base material or the component and separated from the graphene joint. Consists of processes
A method of continuously carrying out these four steps is a method of directly joining a graphene bonded body in which graphenes are directly bonded to the surface of a base material or a component.

The present invention differs from Japanese Patent Application No. 2019-107537 filed earlier in the following three points, and the three differences bring about the following effects.
The first point is to superimpose graphene on top of each other through a liquid having a viscosity that is more than 20 times the viscosity of methanol. That is, when graphenes are superposed on each other via a highly viscous liquid, the adhesive force of the liquid adsorbed on the graphene increases according to the viscosity of the liquid. As a result of repeating the experiment by increasing the viscosity of the liquid for various graphene conjugates having an area of 1 m × 1 m and a thickness of 100 laminated graphenes, the viscosity of the liquid was determined. When the viscosity is increased to more than 20 times the viscosity of methanol, a part of the graphene cluster with the graphene overlapped is taken out from the container, and the graphene cluster is put in a new container without breaking the graphene overlapping state. It turned out that it could be transferred. This makes it possible to place a group of graphene transferred to a new container on the surface of the base material or part, and process the group of graphene into a graphene joint to be bonded to the surface of the base material or part. .. On the other hand, since there are no restrictions on the shape of the new container, there are no restrictions on the shape of the base material or parts to which the graphene joint is bonded.
On the other hand, in the prior application, graphenes are superposed on each other via methanol. For this reason, in the prior application, since the adsorptive force of low-viscosity methanol adsorbing to graphene is small, it is possible to take out a group of graphene from which graphenes are overlapped with each other in a state where the graphenes are overlapped with each other. Can not. Therefore, in the prior application, a graphene conjugate was produced in which graphenes were bonded to each other by frictional heat in a container in which a collection of graphene was produced. Therefore, since the container in which the graphene aggregate is manufactured has two pairs of parallel plate electrodes, the shape of the graphene junction that can be manufactured in the container is limited.
The second point is that graphenes are superposed on the bottom surface of a new container having the shape of the graphene conjugate as the shape of the bottom surface via a liquid whose viscosity has been increased to more than 20 times the viscosity of methanol. In other words, when vibrations in three directions are repeatedly applied to a new container to which the graphene collection has been transferred, the graphene has almost no mass in the graphene collection that overlaps through the liquid, so the liquid has priority in the container. Moving. On the other hand, since the shape of graphene is different for each graphene, when the liquid moves, the graphene collection spreads with the liquid throughout the container, and the graphene collection rearranges. That is, due to the high viscosity of the liquid, the liquid does not dissociate from the surface of graphene. Therefore, when the liquid moves, the graphene accompanied by the liquid moves in the container, and the graphene collection spreads throughout the container. Finally, when vertical vibration is applied, a collection of graphene in which graphenes are overlapped with each other via a liquid is formed on the bottom surface of the container as a shape of the bottom surface. Therefore, the graphene collection can be transferred from the container in which the graphene collection is manufactured to a new container, and a graphene collection in which graphenes are overlapped with each other via a liquid can be formed on the bottom surface of the new container. On the other hand, since there are no restrictions on the shape of the bottom surface of the new container, there are no restrictions on the shape of the graphene joint to be joined to the base material or parts, and there are no restrictions on the base material or parts to be joined to the graphene joint. The vibration acceleration applied to the container is 0.2-0.4 G depending on the mass of the graphene aggregate in which the graphenes are overlapped with each other through the liquid.
By the way, since the graphite particles in which the basal planes made of graphite crystals are laminated have a unique outer shape, the shape of the basal plane is different for each basal plane. Furthermore, the shape of the graphite particles in the collection of graphite particles is different for each graphite particle. Therefore, the shapes of individual graphenes are different in the group of graphene produced by simultaneously breaking all the interlayer bonds of the basal plane made of graphite crystals. Therefore, when vibrations in three directions are applied to the graphene collections that overlap each other through the liquid, as described above, the liquids move, and the graphene collections with the liquid spread over the entire bottom surface of the container. , A collection of graphene rearranges. Finally, when vertical vibration is applied, a collection of graphene in which graphenes are overlapped with each other via a liquid is formed on the bottom surface of the container as a shape of the bottom surface.
On the other hand, in the prior application, the graphene conjugate is manufactured in the container in which the graphene aggregate is manufactured. Therefore, in the prior application, since the graphene joint is manufactured in the container in which the two parallel plate electrode pairs exist, the shape of the graphene joint that can be manufactured is limited.
The third point is that the graphene conjugate bonded to the surface of the base material or the component is composed only of graphene, and is therefore close to the properties of graphene. That is, a group of graphene in which graphenes are superposed on each other via a liquid having an increased viscosity is directly placed at a position where the graphene conjugate on the surface of the base material or the component is joined, and the base material or the component is brought to the boiling point of the organic compound. As the temperature rises, the surface of the graphene cluster is evenly compressed. As a result, the graphene joint is in direct contact with the surface of the base material or the component. Since this graphene conjugate consists only of graphene, it is close to the properties of graphene.
On the other hand, in the prior application, after manufacturing the graphene joint, the metal fine particles or metal oxide are used as a means for covering the graphene joint with fine metal particles or fine particles of metal oxide and crimping the graphene joint to the base material or parts. Use fine particles of. Therefore, in the prior application, the graphene junction is crimped to the base material or the component through the collection of the fine metal particles or the fine particles of the metal oxide. Therefore, the properties of the crimped graphene conjugate are the metal fine particles or the metal oxide. Due to the presence of a collection of fine particles of graphene, it dissociates from the properties of graphene as compared to the graphene conjugate of the present invention.

The present invention comprises the following seven processes.
The first treatment produces graphene aggregates from graphite particle aggregates in methanol. That is, a collection of scaly graphite particles or a collection of massive graphite particles narrowed in the gap between the two parallel plate electrode pairs is immersed in methanol, which is an insulator, and a direct current is applied to the two parallel plate electrode pairs. Apply a potential difference. As a result, an electric field corresponding to the value obtained by dividing the potential difference by the size of the gap between the two parallel plate electrode pairs is generated in the electrode gap in which a collection of scaly graphite particles or a collection of massive graphite particles is present. This electric field simultaneously applies a Coulomb force sufficient for breaking the interlayer bond of the basal plane made of graphite crystals to all the above-mentioned graphite particles to all the π electrons that are responsible for the interlayer bond of the basal plane. As a result, the π electron is released from the constraint on the π orbit, and all the π electrons are separated from the π orbit and become free electrons. That is, when the Coulomb force acting on the π electron is given to the π electron as a force larger than the interaction of the π orbit, the π electron is released from the constraint of the π orbit and becomes a free electron. As a result, all the π electrons that are responsible for the interlayer bonding of the basal plane do not exist in the π orbital, and for all the graphite particles, all the interlayer bonding of the basal plane made of graphite crystals forming the graphite particles is performed at the same time. It will be destroyed. As a result, a collection of basal planes made of graphite crystals, that is, a collection of graphene, is instantly produced in the gap between the pair of two parallel plate electrodes. Since the two parallel plate electrode pairs are immersed in methanol, the graphene deposited in the gap between the two parallel plate electrode pairs does not scatter. This solved the first problem described in paragraph 8.
Methanol has a viscosity of 0.59 mPa · s at 20 ° C. and is an organic compound having a low viscosity. Therefore, the adsorption force of methanol adsorbed on graphene is small. Methanol has a density of 0.793 g / cm ³ , and is an organic compound having a low density. Therefore, graphene precipitated in methanol easily moves in methanol. Further, since methanol is an insulator having a volume resistivity of 3 MΩ · cm or more and a dielectric constant of 33, when a potential difference is applied between two parallel plate electrodes immersed in methanol, two parallel plates are applied. An electric field is generated in the gap between the electrodes.
The second treatment moves a collection of graphene into methanol through the gap between the two parallel plate electrodes. Therefore, the gap between the two parallel plate electrodes is expanded in methanol and further tilted in methanol, after which vibration in three directions is applied to the container filled with methanol. This causes a collection of graphene to move into the methanol through the gap between the two parallel plate electrodes. After that, the two parallel plate electrodes are taken out from the container.
The third treatment separates the graphene aggregates into individual graphenes in methanol. That is, when graphene is deposited in the narrow gap between the pair of two parallel plate electrodes, some graphenes overlap with each other, so that each graphene is separated into individual graphenes in methanol. Therefore, the homogenizer device is operated in methanol, and the impact is repeatedly applied to the graphene aggregate via methanol. On the other hand, the bonding between graphenes is simply that the graphenes overlap each other, and the bonding force between the graphenes is extremely small. In addition, a part of the impact applied to methanol is consumed by the molecular vibration of methanol, but since methanol has low viscosity and low density, the ratio consumed by the molecular vibration of methanol is small, and most of the impact energy. Joins the graphene gathering. This impact is applied to the overlapping portion of graphene, the overlapping graphene is easily separated, and methanol enters the gap between the separated graphenes. As a result, when an impact is repeatedly applied to the graphene aggregate, it is separated into individual graphenes in methanol, and the separated graphenes come into contact with methanol. This solved the second problem described in paragraph 8. Whether or not the samples could be separated into individual graphenes is determined by taking out a plurality of samples from methanol and observing the samples with an electron microscope to determine whether or not the samples could be separated into individual graphenes. From this result, the operating conditions and operating time of the homogenizer device are obtained in advance.
When an ultrasonic homogenizer device is used, the generation of ultrafine and enormous numbers of bubbles, which are one order of magnitude smaller than graphene, and the disappearance of the bubbles are determined according to the vibration cycle of the ultrasonic vibration frequency. It is continuously repeated in methanol (this phenomenon is called cavitation), and a shock wave when a huge number of bubbles burst is continuously and repeatedly added to the entire group of graphenes via methanol. When a shock wave is applied to a portion where graphenes overlap each other, the overlapping graphenes are separated, methanol enters the gaps between the separated graphenes, and the graphenes are separated into individual graphenes in a short time.
In the fourth treatment, a group of graphene in which graphenes are superposed with each other via a liquid having an increased viscosity is formed on the bottom surface of a container in which the graphene collections are dispersed as a shape of the bottom surface. Therefore, the organic compound dissolved in methanol is mixed with the methanol in the container in an amount having a viscosity exceeding 20 times the viscosity of the methanol. After that, vibrations in three directions of left-right, front-back, and up-down are repeatedly applied to the container, and finally vibrations in the up-down direction are applied. As a result, a collection of graphene in which graphenes are overlapped with each other via a liquid having an increased viscosity is formed on the bottom surface of the container as a shape of the bottom surface. This solved the third problem described in paragraph 8.
In other words, when repeated vibrations in three directions are applied to a container in which a collection of graphene separated into individual graphene exists in a liquid with increased viscosity, the graphene has almost no mass, so that the liquid is inside the container. Priority is given to moving in three directions. At this time, since the size of graphene is different for each graphene, the graphene aggregate spreads with the liquid throughout the container, and the graphene aggregate is rearranged in the liquid. That is, due to the high viscosity of the liquid, the liquid does not dissociate from the surface of graphene. Therefore, when the liquid moves in the container in three directions, the graphene accompanied by the liquid spreads and moves in the container. Finally, when vertical vibration is applied, a collection of graphene in which graphenes are overlapped with each other via a liquid is formed on the bottom surface of the container as a shape of the bottom surface.
In the fifth treatment, a group of graphene having the shape of a graphene joint to be bonded to a base material or a component is formed on the bottom surface of a new container as a bottom surface shape. That is, the graphene bonded body to be bonded to the surface of the base material or the component has various shapes. Therefore, in the fourth treatment, a collection of graphene in which graphenes are overlapped with each other via a liquid cannot be processed into various shapes. For this reason, a part of the graphene aggregate that has been subjected to the fourth treatment is filled in a new container having the shape of the graphene joint as the shape of the bottom surface, and the container is vibrated in three directions of left and right, front and back, and up and down. Add repeatedly, and finally add vertical vibration. As a result, similar to the result of the fourth treatment, a collection of graphene in which graphenes are overlapped with each other via the increased viscosity liquid is formed on the bottom surface of the new container as a bottom surface shape.
In the sixth treatment, the graphene joint is bonded to the surface of the base material or the component. For this reason, the group of graphene that has been subjected to the fifth treatment is placed at the position where the graphene joints on the surface of the base material or parts are joined, and the compression member having the shape of the group of graphene is used as the group of graphene. Overlay. After that, the base material or the component is heated to the boiling point of the organic compound, and the graphene aggregate is compressed by the compression member. The compression member is, for example, a plate made of ceramics, which has a high melting point and is hard to soften, has high bending strength and is hard to break, and has high insulation resistance and electrons are bound, as a simple compression member. Is used. This ceramic plate is placed on a collection of graphene, and a weight is placed on the ceramic plate. Alternatively, the surface of the compression member may be evenly compressed by the compressor. At this time, methanol and organic compounds are vaporized in order from the aggregate of graphene. In addition, impurities consisting of the base material or parts and water or organic substances existing in the graphene aggregate are also vaporized, and both the surface of the base material or parts and the graphene aggregate are cleaned. Furthermore, compressive stress acts on the graphene aggregate, and the contact surfaces of the overlapping graphene are directly bonded by friction and adhesion, and the graphene that comes into contact with the surface of the base material or part is the surface of the base material or part. A graphene joint consisting of a collection of graphene to which graphene is bonded to each other is bonded to the surface of a base material or a component. This solved the fourth problem described in paragraph 8.
The ceramic plate that compresses a collection of graphene has a high melting point and high insulating properties, so it does not join with graphene. In addition, when methanol, organic compounds, and impurities are vaporized, the graphene aggregate and the surface of the base material or parts have a positive pressure compared to the outside world. Gases that become impurities cannot enter from the outside world. Therefore, both the surface of the substrate or component and the graphene cluster remain clean. Graphene is a tough material with a breaking strength of 42 N / m, which is more than 100 times stronger than steel, and even if a large compressive load that breaks the iron plate is applied when joining graphene to each other, Graphene does not destroy. Therefore, there are no restrictions on the shape and material of the base material or part to which the graphene joint is bonded, as long as the base material or part is not destroyed when the graphene aggregate is compressed. Further, the vaporized methanol and the organic compound are recovered by a recovery machine, and since the boiling points of both are different, the methanol and the organic compound are separated by the difference in boiling point, and the separated methanol and the organic compound are reused.
In the seventh treatment, the weight placed on the compression member is removed, an impact is applied to the side surface forming the thickness of the compression member, and the compression member is bonded to the base material or the surface of the component and separated from the graphene joint. When no weight is used, the impact is directly applied to the side surface of the compression member. As a result, a base material or a component in which the graphene joint is bonded to the surface is obtained.
All of the above seven processes are extremely simple processes. Methanol and organic compounds are general-purpose industrial chemicals. Graphite particles are also an inexpensive industrial material. Therefore, in this method, when seven extremely simple treatments are carried out in succession using inexpensive graphite particles, methanol and an organic compound, a graphene conjugate in which graphenes are overlapped is formed on the surface of a base material or a component. NS. As a result, the fifth problem described in paragraph 8 was solved, and all the problems were solved.

The graphene conjugate produced by the production method described above brings about the following effects.
First, it is possible to impart properties similar to graphene to the base material and parts. That is, graphene has a thickness of 0.332 nm, which corresponds to the size of a carbon atom, is extremely lightweight, and has almost no mass. Moreover, since the thickness is extremely thin, the presence of graphene cannot be visually confirmed. Moreover, the area of graphene produced from graphite particles is small. For this reason, it is difficult to directly bond graphene to a base material or a component. According to the present invention, a graphene joint can be bonded to the surface of a base material or a component. This graphene conjugate is composed only of graphene and is close to the properties of graphene. As a result, it is possible to impart properties similar to graphene to the base material and parts.
Secondly, there are few restrictions on the base material or parts to which the graphene joint is bonded. That is, in the sixth treatment described above, when the group of graphene arranged on the surface of the base material or part is uniformly compressed, if the base material or part is not destroyed, the base material or part to which the graphene joint is bonded is joined. There are no restrictions on the material and shape of.
Third, there are no restrictions on the area, thickness and shape of the graphene joint. That is, in the fifth process described above, there is no restriction on the shape of the bottom surface of the container used when forming a group of graphene corresponding to the graphene junction having the shape of the bottom surface on the bottom surface of the container. There are no restrictions on area and shape. Further, in the first treatment described above, since there is no restriction on the amount of graphene dispersed in methanol, there is no restriction on the area and thickness of the graphene conjugate.
Fourth, the graphenes are firmly bonded to each other, and the graphene bonded body is firmly bonded to the base material or the component. That is, in the sixth treatment described above, the graphene is in a clean state without impurities, and the contact surfaces of the overlapping graphene are bonded by friction and adhesion, so that the contact surfaces of the graphene are firmly bonded to each other. In addition, the surface of the base material or parts is also in a clean state without impurities, and the graphene in the clean state is bonded to the surface of the base material or parts in a clean state by friction, so that the graphene joint is firmly attached to the base material or parts. Join. That is, graphene consists of the basal plane of graphite crystals and is a perfect flat surface with no irregularities. Therefore, when the vaporization of various gases is completed, the gap between the contact surfaces of the overlapping graphenes becomes even thinner than the thickness of the graphenes. When such a collection of graphene is compressed, the contact surfaces of the overlapping graphenes move very slightly, and frictional heat is generated on the contact surfaces of the overlapping graphenes. In addition, compressive stress acts on the overlapping graphene contact surfaces, causing the contact surfaces to adhere to each other. As a result, the contact surfaces of graphene are firmly bonded to each other by friction and adhesion. On the other hand, the surface of the base material or component has irregularities made of submicrons based on the surface roughness. Therefore, the compressed graphene comes into contact with the convex portion of the surface of the base material or the component, and excessive frictional heat is generated in the convex portion, and the frictional heat firmly joins the surface of the base material or the component and the graphene. do. Therefore, the gap between the base material or component and the graphene joint becomes submicron, and all liquids cannot enter this gap.
Fifth, the graphene conjugate bonded to the substrate or component does not change over time no matter what environment it is used in. That is, the graphene conjugate is composed only of graphene having a melting point of more than 3000 ° C. and has excellent heat resistance. Graphene is an extremely stable substance that is not eroded by acids or alkalis.
Sixth, the surface of the graphene joint has water repellency, oil repellency and antifouling property. That is, the unevenness of the surface of the graphene joint is only 0.332 nm of the thickness of graphene, which is close to a perfect flat surface. Therefore, the surface of the graphene bonded body exhibits superhydrophobicity with a contact angle close to 180 degrees, and the surface is provided with water repellency, oil repellency, and antifouling property.
Graphene has both thermal conductivity equivalent to 4.5 times the thermal conductivity of silver and electrical conductivity equivalent to only 23 times the specific resistance of copper. For this reason, graphene joints include electrodes and contacts having a small area, elongated wiring patterns, and heat conductive sheets having a large area. Further, since the graphene joint has an antistatic function, an electromagnetic wave shielding function, and a heat radiating function, these functions can be imparted to the base material and parts. It is also used as an electromagnetic wave shielding sheet or a heat radiating sheet having a large area. Further, since the graphene joint has excellent corrosion resistance and heat resistance, the base material or component can be covered with a coating film having excellent corrosion resistance and heat resistance. Further, since graphene has a shear modulus of 440 GPa and is the toughest substance, wear resistance and non-destructive property can be imparted to the base material or parts. On the other hand, since graphene is a relatively new material, the products that utilize the properties of the graphene conjugate produced in the present invention are not limited to the above-mentioned products, and it is expected that products in a completely new field will be put into practical use.

Here, in the first treatment, from the graphite crystals forming the graphite particles in the graphite particles narrowed to the gap between the two parallel plate electrode pairs by the electric field applied to the gap between the two parallel plate electrode pairs. The phenomenon that all the interlayer bonds of the base surface are simultaneously destroyed will be described.
The carbon atom forming the basal plane made of graphite crystals in graphite particles has four valence electrons. Three of these valence electrons are basal planes made of graphite crystals, that is, σ electrons forming graphene. These σ electrons covalently bond with the σ electrons of three adjacent carbon atoms on the basal plane at an angle of 120 degrees to form a strong hexagonal network structure two-dimensionally. The remaining one valence electron is a π electron, which exists in a π orbit extending in a direction perpendicular to the basal plane. These π electrons are bonded to the π electrons of adjacent carbon atoms in the vertical direction perpendicular to the basal plane with a weak bonding force, and the basal planes are laminated in layers based on this weak bonding force. That is, the basal plane, that is, graphene, is layered to each other by the interaction of π orbitals, which is a weak bonding force. Therefore, the graphite particles have a property of being easily peeled off at the basal plane made of graphite crystals, that is, mechanical anisotropy. This mechanical anisotropy is known as the lubricity of graphite particles.
When an electric field is applied to these graphite particles, a Coulomb force due to the electric field acts on all π electrons. When the Coulomb force acting on the π electron acts on the π electron as a force larger than the interaction of the π orbit acting on the π electron, the π electron is released from the constraint on the π orbit. As a result, all π electrons move away from the π orbit and become free electrons. As a result, all the π electrons, which are the bearers of the interlayer bond of the basal plane made of graphite crystals, are not on the π orbital, so that the interlayer bonds of the basal plane are destroyed at the same time. That is, when the π electron moves a distance of the interlayer distance b of the graphite crystal by the Coulomb force F, the π electron performs work W (W = b · F). This work W is 35 millielectronvolts, which is the magnitude of the interaction of π orbitals per atom acting on π electrons (electronbolts are units that express the magnitude of energy possessed by electrons, and 1 electronvolt is 1. ^Beyond (corresponding to 62 × 10-19 joules), the π electron is released from the constraint of the interaction of the π orbit and becomes a free electron. For example, when the gap between two parallel plate electrode pairs is separated by 100 μm and a DC potential difference of 10.6 kilovolt or more is applied between the electrodes, the interlayer bond of all the basal planes made of graphite crystals is instantly broken. Will be done. As described above, a large amount of graphene can be inexpensively produced by an extremely simple means of applying an electric field to a collection of inexpensive graphite particles. In addition, since the interlayer bonds of all the basal planes are broken at the same time, the obtained fine substance is surely the basal plane made of graphite crystals, that is, graphene.
The group of graphite particles referred to here means a group of relatively small amounts of graphite particles of about 1 g to 100 g. That is, the scaly graphite particles or the massive graphite particles are ^{fine particles having a bulk density of 0.2-0.5 g / cm 3} and a particle size of 1-300 microns. Therefore, it is easy to pull the aggregate of graphite particles into the gap between the two parallel plate electrode pairs, and it is also easy to apply a potential difference to the two parallel plate electrode pairs. When a potential difference is applied to the gap between the pair of two parallel plate electrodes, an electric field is generated in all the regions where the graphite particles are attracted. This electric field acts on the π electron as a Coulomb force larger than the interaction of the π orbit, and the π electron is released from the constraint on the π orbit and becomes a free electron. As a result, all the interlayer bonds of the basal plane made of graphite crystals in the graphite particles are simultaneously broken, and the basal plane made of graphite crystals, that is, a collection of graphene is produced in the gap between the pair of two parallel plate electrodes.
Here, the number of graphene is calculated by arithmetic. Here, it is assumed that all graphite particles are composed of spheres having a diameter of 25 microns, and since the true density of graphite is 2.25 × 10 ³ kg / m ³ , the weight of one graphite particle is high. Is only 1.84 x ^10-8 g. Assuming that the average thickness of the graphite particles is 10 microns, the interlayer distance is 3.354 angstroms. Therefore, the scaly graphite particles having a thickness of 10 microns have 297,265 basal planes, that is, graphene. Are laminated. Therefore, by breaking all the interlayer bonds on the basal plane made of graphite crystals, 297,265 graphene aggregates can be obtained from only one spherical graphite particle. Therefore, for an aggregate of only 1 g of spherical graphite particles, an aggregate of 1.62 × 10 ¹³ graphenes can be obtained when all the interlayer bonds on the basal plane are broken. Therefore, according to this production method, an enormous number of graphene aggregates can be obtained from a small amount of graphite particles.

In the method of directly bonding the graphene conjugate in which the graphenes described in paragraph 9 are directly bonded to the surface of the base material or the component, the organic compound described in paragraph 9 is an organic compound belonging to glycols, and the glycols The organic compound to which it belongs is used as the organic compound described in paragraph 9, and the graphene junction is bonded to the surface of the substrate or component according to the method of bonding the graphene conjugate to the surface of the substrate or component described in paragraph 9. This is a method in which a graphene bonded body in which graphenes are directly bonded to each other is directly bonded to the surface of a base material or a component.

That is, the organic compound belonging to glycols is an organic compound that dissolves in methanol and has a viscosity exceeding 30 times the viscosity of methanol, and can be used as the organic compound described in paragraph 9.
Glycols include ethylene glycols and propylene glycols.
Further, the ethylene glycols include ethylene glycol having a viscosity of 21 mPa · s (21 ° C.) and a boiling point of 197 ° C., diethylene glycol having a viscosity of 36 mPa · s (20 ° C.) and a boiling point of 244 ° C., and a viscosity of 48 mPa. There are triethylene glycol having a viscosity of s (20 ° C.) and a boiling point of 287 ° C., and tetraethylene glycol having a viscosity of 55 mPa · s (20 ° C.) and a boiling point of 314 ° C. Both are soluble in methanol and have a viscosity of more than 30 times the viscosity of methanol. Therefore, ethylene glycols can be used as the organic compound described in paragraph 9.
On the other hand, propylene glycol includes propylene glycol having a viscosity of 56 mPa · s (20 ° C.) and a boiling point of 188 ° C. and dipropylene glycol having a viscosity of 116 mPa · s (25 ° C.) and a boiling point of 227 ° C. .. Both are soluble in methanol and have a viscosity of more than 30 times the viscosity of methanol. Therefore, propylene glycol can be used as the organic compound described in paragraph 9.

It is explanatory drawing which enlarged and represented a part of the side surface which the graphene joint body which graphene was directly bonded to each other was directly bonded to an aluminum plate.

Example 1
In this embodiment, a graphene joint obtained by joining graphene to each other is formed on an aluminum plate as a 1 m × 1 m sheet according to the method described in paragraph 9.
First, 2 liters of methanol was filled into a container with a flat bottom of 1.2 m x 1.2 m.
Next, with respect to the parallel plate electrode in which the effective area of the electrode in which the electric field is generated is 1 m × 1 m, scaly graphite particles (for example, Z-100 of Ito Graphite Industry Co., Ltd.) cover the entire effective surface in which the electric field is generated. 10 g of the above was uniformly squeezed. This parallel plate electrode is immersed in a container filled with methanol, the other parallel plate electrode is superposed on the parallel plate electrode, and the two parallel plate electrodes are a collection of scaly graphite particles. A 12 kilovolt DC voltage was applied between the electrodes, combined with a gap of 100 μm. Next, the gap between the two parallel plate electrodes is expanded, the two parallel plate electrodes are tilted in methanol, and vibration acceleration in three directions consisting of 0.2 G is repeatedly applied to the container, and then the container is used. Two parallel plate electrodes were taken out from. Further, ultrasonic vibration of 20 kHz was applied to the methanol in the container for 2 minutes by the horn of an ultrasonic homogenizer device (product LUH300 of Yamato Scientific Co., Ltd.). After this, the horn was taken out of the container. Next, 500 cc of propylene glycol (for example, a product of Showa Chemical Co., Ltd.) was mixed in the container. The viscosity of the mixed solution increases 25 times the viscosity of methanol at 20 ° C. Further, the vibration acceleration in three directions consisting of 0.3 G was repeatedly applied to the container, and finally, the vibration acceleration in the vertical direction consisting of 0.3 G was applied.
After that, a container having a flat bottom surface of 1 m × 1 m and having open sides on all sides was filled with approximately half of the sample prepared above. After that, the vibration acceleration in three directions consisting of 0.3 G was repeatedly applied to the container, and finally, the vibration acceleration in the vertical direction consisting of 0.3 G was applied. Further, the four side surfaces were opened, and a sample having an area of 1 m × 1 m in the container and having a thin thickness was taken out. This sample is placed on an aluminum plate having an area of 1 m × 1 m and a thickness of 5 mm, and an alumina plate having an area of 1 m × 1 m and a thickness of 1 cm is placed on the sample. Five 100 kg weights were placed on the surface at intervals so as to form a cross mark, and the temperature was raised to 190 ° C. After that, the weight was removed, and impacts were simultaneously applied to three places on the side surface of the alumina plate to remove the alumina plate from the sample.
Next, the plane and side surfaces of the prepared sample were observed and analyzed using an electron microscope. As the electron microscope, an extremely low acceleration voltage SEM manufactured by JFE Techno Research Co., Ltd. was used. This device can observe the surface with an extremely low acceleration voltage from 100 volts, and has the feature that the surface of the sample can be directly observed without forming a conductive film on the sample. First, the secondary electron beam between 900 and 1000 volts of the backscattered electron beam from the plane of the sample was taken out and image processed. An extremely thin step was confirmed on the flat surface of the sample. Next, the secondary electron beam between 900 and 1000 volts of the backscattered electron beam from the side surface of the sample was taken out and image processing was performed. The extremely thin substances formed 10 layers and overlapped with each other. Furthermore, as a result of image processing of the energy of the characteristic X-ray and its intensity, it was confirmed that only carbon atoms were present and the sample was a graphene conjugate in which graphenes overlapped with each other.
In FIG. 1, a part of the side surface of the graphene junction in which graphenes overlap each other is enlarged and schematically shown. 1 is graphene and 2 is an aluminum plate.
Even if the prepared sample was dropped from a height of 2 m, the graphene joint did not peel off from the aluminum plate and the graphene joint was not damaged. Therefore, the graphenes were bonded to each other with a constant bonding force. At the same time, the graphene joint is bonded to the aluminum plate with a constant bonding force.

Example 2
In this example, the remaining part of the sample in which graphenes are overlapped with each other via the methanol solution of propylene glycol prepared in Example 1 has a flat bottom surface of 1 cm × 50 cm, and all four sides are open. Filled in a container that can. After that, the vibration acceleration in three directions consisting of 0.3 G was repeatedly applied to the container, and finally, the vibration acceleration in the vertical direction consisting of 0.3 G was applied. Further, the four side surfaces were opened, and a sample having an area of 1 cm × 50 cm in the container and having a thin thickness was taken out. This sample is placed on an aluminum plate having an area of 1 cm × 50 cm and a thickness of 5 mm, and an alumina plate having an area of 1 cm × 50 cm and a thickness of 1 cm is placed on the sample. Three 10 kg weights were placed on top of the weight at intervals and the temperature was raised to 190 ° C. Then, after removing the weight, an impact was simultaneously applied to three places on the side surface of the alumina plate to remove the alumina plate from the sample.
Next, the plane and the side surface of the prepared sample were observed and analyzed using an electron microscope in the same manner as in Example 1. As a result, in the sample, about 100 layers of graphene overlapped to form a graphene contact concrete.
Two examples of joining a graphene joint to an aluminum plate have been described. When compressing a graphene cluster in which graphenes overlap each other on a base material or a component, compressive stress is evenly applied to the compressive stress. If it can withstand, there are no restrictions on the base material or parts.

1 graphene 2 aluminum plate

Claims (2)

The method of directly joining the graphene bonded body, which is directly bonded to each other, to the surface of the base material or parts, is
A collection of scaly graphite particles or a collection of massive graphite particles is flatly packed on the surface of one of the parallel plate electrodes forming an electrode pair consisting of two parallel plate electrodes, and the one parallel plate electrode is placed in a container. Immersed in packed methanol, the other parallel plate electrode is superposed on the one parallel plate electrode via the aggregate of scaly graphite particles or the aggregate of the massive graphite particles, and two parallel plates are superposed. An electrode pair composed of electrodes is immersed in the graphite, and then a DC potential difference is applied to the gap between the electrode pairs, whereby the magnitude of the potential difference is divided by the size of the gap between the electrode pairs. An electric field corresponding to is applied to the aggregate of the scaly graphite particles or the aggregate of the lump graphite particles, and the application of the electric field causes the basal plane made of graphite crystals forming the scaly graphite particles or the lump graphite particles. All of the interlayer bonds are simultaneously broken to form an aggregate of graphene composed of the basal plane in the gap between the electrode pairs, after which the gap between the electrode pairs is expanded and the electrode pair is tilted in the methanol. Further, vibrations in three directions of left-right, front-back, and up-down are repeatedly applied to the container to move the graphene aggregate into the methanol through the gap between the electrode pairs, and then the two parallel sheets are moved from the container in parallel. The flat plate electrode is taken out, and further, the homogenizer device is operated in the methanol in the container, and impact is repeatedly applied to the graphene aggregate via the graphite, and the graphene aggregates are collected one by one in the graphite. The homogenizer device is taken out from the container, and the homogenizer device is taken out from the container. The compound is mixed in the container in an amount such that the viscosity of methanol in the container becomes more than 20 times the viscosity, and the aggregate of the graphite separated into each graphite is the organic compound. Is dispersed in the solution dissolved in the methanol. After that, vibrations in three directions of left and right, front and back, and up and down are repeatedly applied to the container, and finally, vibrations in the up and down directions are applied to the graphenes via the solution. In the first step of superimposing the graphite and forming a collection of the overlapping graphene on the bottom surface of the container as the shape of the bottom surface.
A new container having the shape of a graphene junction in which graphenes are joined as the shape of the bottom surface is filled with a part of a collection of graphenes in which graphenes overlap each other via the solution, and the container is filled with left and right, front and back, and so on. The graphenes are repeatedly vibrated in three directions, up and down, and finally vibrated in the up and down direction to form a collection of graphene in which graphenes are overlapped with each other via the solution, as the shape of the bottom surface of the new container. The second step and
From the new container, a group of graphene in which graphenes are overlapped with each other is taken out through the solution, and the group of graphene is placed at a position where it is joined to the surface of a base material or a component, and further, the group of graphene is placed. A compression member having a shape is superposed on the surface of the graphene aggregate, after which the base material or the component is heated to the boiling point of the organic compound and the graphene aggregate is compressed by the compression member. As a result, the methanol and the organic compound are vaporized in order from the graphene aggregate, and the contact surfaces of the overlapping graphenes in the graphene aggregate are bonded to each other, and the surface of the base material or the component is formed. The graphene in contact with the base material or the surface of the component is bonded to the surface of the base material or the component, and the graphene junction composed of a collection of graphene bonded to the graphene is bonded to the surface of the base material or the component. Process and
A fourth method in which an impact is applied to a side surface forming the thickness of the compressed member with respect to the compressed member obtained by compressing a collection of graphene, and the compressed member is bonded to the surface of the base material or the component and separated from the graphene joint. Consists of processes
The method of carrying out these four steps in succession is a method of directly joining a graphene bonded body in which graphenes are directly bonded to the surface of a base material or a component. In the method of directly bonding the graphene conjugate in which the graphenes according to claim 1 are directly bonded to the surface of the base material or the component, the organic compound according to claim 1 is an organic compound belonging to glycols, and the glycol An organic compound belonging to the same category is used as the organic compound according to claim 1, and a graphene conjugate is attached to the surface of the substrate or component according to the method of bonding a graphene conjugate to the surface of the substrate or component according to claim 1. A method of directly bonding graphene bonded bodies, which are directly bonded graphene to each other, to the surface of a base material or component.

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