JP4339870B2 - Nanocarbon production method and nanocarbon production apparatus - Google Patents

Description

The present invention relates to a nanocarbon manufacturing method and a nanocarbon manufacturing apparatus.
In particular, it is suitable for a method for producing nanoscale (10 ⁻⁶ to 10 ⁻⁹ m) size particles mainly composed of carbon.

Hereinafter, an electron emission source will be described as an example.
The field electron emission source is energy-saving and has a long life compared to a thermionic emission source that requires heating. At present, field electron emission source materials include semiconductors such as Si (silicon), metals such as Mo (molybdenum) and W (tungsten), as well as nanoscale-sized carbon materials represented by nanotubes (hereinafter, Carbon-based nanomaterials). Among these, carbon nanomaterials have the characteristics that they themselves have sufficient size and sharpness to concentrate the electric field, are relatively chemically stable, and have excellent mechanical strength. Promising as a source.

  Conventional methods for producing nanotubes, which are representative of carbon-based nanomaterials, include laser ablation, arc discharge between graphite electrodes in an inert gas, and chemical vapor deposition (CVD) using hydrocarbon gas. . Among these, nanotubes produced by the arc discharge method have few atomic arrangement defects and are suitable for a field electron emission source.

The process of the conventional arc discharge method is as follows (refer patent document 1).
After placing two graphite electrodes facing each other in the container, the container is once evacuated, and then an inert gas is introduced to generate an arc. The arc anode evaporates violently, producing soot, and deposits on the cathode surface. The arc discharge is continued for several minutes or more, and then the apparatus is opened to the atmosphere, and the cathode deposit is taken out. The cathode deposit is composed of a soft core including nanotubes and a hard shell not including nanotubes. When graphite containing a catalytic metal is used for the anode, nanotubes are present in the soot. A nanotube is taken out from the soft core or soot, and the nanotube is supported on a substrate to be an electron emission source.
JP 2000-95509 A

  Problems in manufacturing a carbon-based nanomaterial such as a nanotube and an electron emission source made of the carbon-based nanomaterial in the conventional arc discharge method are as follows.

  At the time of nanomaterial production, a vacuum vessel, a vacuum exhaust device, and an inert gas introduction device are necessary, and the device cost is relatively high. Moreover, exhaust and air release must be repeated, and the process is long. Then, after completion of the process, it is necessary to collect the cathode deposit or soot and clean the apparatus every time, which is not suitable for continuous mass production. Furthermore, in order to create an electron-emitting device using the carbon-based nanomaterial produced by this method, the soft core and the hard shell are separated, soot is isolated, purified, and supported on the substrate. This process is necessary.

  The present invention does not necessarily require a process container or the like, and the soot containing nanocarbon is obtained by evaporating an arc target material mainly composed of carbon by arc discharge using a welding arc torch or an apparatus having a similar structure. A method for generating and collecting the soot is provided, and a manufacturing apparatus for the method is provided.

In addition, in order to facilitate the production and recovery, there is provided a method in which a base material exists around the discharge peripheral region or the soot scattering portion, and the soot deposited on the base material is recovered through the base material, and the manufacturing is provided. A device is provided. Similarly, the present invention provides a method of recovering soot dispersed and dissolved in a fluid (liquid) around a discharge surrounding region or around a soot scattering portion and providing the manufacturing apparatus. Similarly, the present invention provides a method for recovering soot deposited or dispersed on a granular material around a discharge surrounding area or around a soot scattering portion via a fluid, and a manufacturing apparatus therefor.
Further, the recovered nanocarbon or composite soot of nanocarbon and metal fine particles (composite material) can be used as a hydrogen storage material.

The method for producing nanocarbon according to claim 1 comprises:
Arcing by applying a voltage between the first electrode and the second electrode in the atmosphere, in the air, or in a gas atmosphere, the step of disposing the first electrode and the second electrode mainly composed of a carbon material. A step of generating discharge, a step of evaporating the carbon material of the second electrode by the arc discharge to generate soot containing nanocarbon, and a step of recovering soot containing nanocarbon. It is characterized by comprising control means for controlling the discharge direction.

The method for producing nanocarbon according to claim 2 comprises:
Arcing by applying a voltage between the first electrode and the second electrode in the atmosphere, in the air, or in a gas atmosphere, the step of disposing the first electrode and the second electrode mainly composed of a carbon material. A step of generating a discharge; a step of evaporating the carbon material of the second electrode by the arc discharge to generate soot containing nanocarbon; and a step of recovering the soot containing nanocarbon. The discharge direction of the soot is controlled by supplying a specific gas or air to the generation region.

The method for producing nanocarbon according to claim 3,
Arcing by applying a voltage between the first electrode and the second electrode in the atmosphere, in the air, or in a gas atmosphere, the step of disposing the first electrode and the second electrode mainly composed of a carbon material. A step of generating electric discharge, a step of evaporating the carbon material of the second electrode by the arc discharge to generate soot containing nanocarbon, and a step of collecting the soot containing nanocarbon. The discharge direction of the soot is controlled by adjusting an angle formed by the electrode and the second electrode in a range of 45 degrees to 135 degrees.

The method for producing nanocarbon according to claim 4 is the method for producing nanocarbon according to claim 3,
The carbon material of the second electrode is characterized by using a carbon material containing or incorporating an additive, or a carbon material in which the additive is dispersed, applied, plated or coated on a part or all of the surface. .

The method for producing nanocarbon according to claim 5 is the method for producing nanocarbon according to claim 3,
The arc discharge is performed while supplying a specific gas or air to a region where the arc discharge is generated.

The method for producing nanocarbon according to claim 6 is the method for producing nanocarbon according to claim 2 or 5,
The arc discharge is performed while supplying the specific gas or the air from the first electrode side to the arc discharge generation region.

The method for producing nanocarbons according to claim 7 is the method for producing nanocarbons according to claim 2 or 5,
The first electrode is a torch electrode provided in an arc torch, and a specific gas or air is supplied to the arc torch while moving the torch electrode and the second electrode relative to each other to generate the arc discharge The method includes a step of generating soot containing nanocarbon by evaporating the carbon material of the second electrode by the arc discharge while supplying the specific gas or the air.

The nanocarbon production apparatus according to claim 8,
A first electrode and a carbon material containing a carbon material or an additive, or an electrode having a second electrode mainly composed of a carbon material having an additive formed on the surface thereof; A voltage is applied between the first electrode and the second electrode in the air or in a gas atmosphere to generate arc discharge, and the carbon material is evaporated by the arc discharge to generate soot containing nanocarbon. An arc generating means comprising a power source for causing the power supply, a recovery member for recovering the soot, and a control means for controlling the discharge direction of the soot are provided.

The nanocarbon production apparatus according to claim 9,
A first electrode and a carbon material containing a carbon material or an additive, or an electrode having a second electrode mainly composed of a carbon material having an additive formed on the surface thereof; A voltage is applied between the first electrode and the second electrode in the air or in a gas atmosphere to generate arc discharge, and the carbon material is evaporated by the arc discharge to generate soot containing nanocarbon. An arc generating means comprising a power source for causing the soot, a recovery member for recovering the soot, and a specific gas supply means for supplying a specific gas to the arc discharge generation region in order to control the discharge direction of the soot. It is a feature.

The nanocarbon manufacturing apparatus according to claim 10,
A first electrode and a carbon material containing a carbon material or an additive, or an electrode having a second electrode mainly composed of a carbon material having an additive formed on the surface thereof; A voltage is applied between the first electrode and the second electrode in the air or in a gas atmosphere to generate arc discharge, and the carbon material is evaporated by the arc discharge to generate soot containing nanocarbon. An arc generating means comprising a power source for generating the electric power, a collecting member for collecting the soot, and means for adjusting an angle formed by the first electrode and the second electrode in a range of 45 degrees to 135 degrees. It is said.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method and manufacturing apparatus of nanocarbon very easy can be provided.
In addition, it is possible to provide a method and an apparatus for producing a carbon-based nanomaterial that can be easily produced and can be continuously produced in large quantities.
Furthermore, the manufacturing method and manufacturing apparatus of the carbon-type nanomaterial which can control the discharge | release direction of nanocarbon (soot) can be provided.
Furthermore, it is possible to provide a method and apparatus for producing a carbon-based nanomaterial that can prevent cathode deposits from being deposited.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the configuration shown in the drawing, and various design changes are possible.

In the present invention, carbon nanotube, carbon nanofiber, carbon nanoparticle (including nanohorn), CN nanotube, CN (nano) fiber, CN nanoparticle, BCN nanotube, BCN (nano) fiber, BCN nanoparticle, fullerene, or these The mixture of these materials will be collectively referred to as nanocarbon materials.
The soot containing the nanocarbon material of the present invention contains only carbon or at least metal fine particles in addition to carbon.

  FIG. 1 shows a nanocarbon production method, a nanocarbon patterning method, a nanocarbon and a composite material of nanocarbon and metal fine particles (composite soot), a nanocarbon substrate, and an electron emission source according to an embodiment of the present invention. This is a manufacturing apparatus (including a patterning apparatus) used in the manufacturing method.

The present embodiment uses a general-purpose TIG welding arc torch (inert gas arc welding) and a power source (welding power source) in the atmosphere (or atmospheric pressure) or in the air or in a predetermined gas atmosphere. For example, arc discharge is generated for a short period of time to the end of the metal, for example, the material to be arced is evaporated to generate soot containing nanocarbon, and the soot is deposited on a base material which is an example of a collecting member (collecting member) It is to be deposited.
Here, the air roughly includes a gas composition of nitrogen: oxygen = 4: 1. Moreover, in the air includes, for example, about 0.5 to 1.5 atmospheric pressure (50 kPa to 150 kPa).

  TIG welding is a welding method in which arc discharge is usually generated between a non-consumable W (tungsten) electrode and a base material in an inert gas encapsulation, and a filler metal is added separately if necessary.

  As shown in FIG. 1, the manufacturing apparatus of the present invention includes a welding arc torch 1 having a torch electrode 10 as a first electrode, and a second electrode that is disposed opposite to the arc torch 1. A voltage is applied between the material 2 and the arc torch 1 and the arc material 2 (for example, contact ignition, high voltage application, high frequency application, etc.) to generate an arc 4 to generate the arc material 2 A power source 5 for welding that causes soot containing nanocarbon to evaporate, a substrate (base material) 3 such as glass that is disposed opposite to the arc 4 and serves as a recovery member for depositing the soot, and The gas cylinder 6 is a gas supply source for supplying a specific gas to the arc torch 1, and a gas regulator and a flow meter 7 for adjusting the flow rate of the specific gas from the gas cylinder 6. The torch electrode 10 and the arced material 2 containing a carbon material as a main component are disposed to face each other in the air or in the air. Reference numeral 8 denotes the tip of the arc torch 1. Reference numeral 14 denotes soot deposited on the substrate 3.

  FIG. 2 is an enlarged sectional view of the tip 8 of the arc torch 1 in the nanocarbon manufacturing apparatus shown in FIG. As shown in FIG. 2, the tip 8 of the arc torch 1 includes a nozzle 9 of the arc torch 1, a torch electrode 10 made of tungsten or the like as the first electrode, an electrode holder 11 that holds the torch electrode 10, The space between the nozzle 9 and the electrode holder 11 and the encapsulated gas 12 supplied to the arc 4 (arc discharge generation region) generated between the arc torch 1 and the arc material 2 It consists of a flow path.

The general-purpose TIG welding power source 5 is configured to flow a specific gas 12 through the arc torch 1 and normally supplies Ar (argon) gas. In the production of nanocarbon, the type of gas to be used is not particularly limited, and rare gas such as Ar and He (helium), air, carbon dioxide gas such as N ₂ (nitrogen) gas, CO ₂ (carbon dioxide), O ₂ (Oxygen) gas, H ₂ (hydrogen) gas, or a mixed gas thereof may be flowed. Moreover, it is not necessary to flow anything. However, it is more preferable to flow the gas 12 through the arc torch 1.

In particular, when a rare gas is used, since the nanocarbon and the rare gas do not cause a chemical reaction, it is most preferable to use the rare gas because the generated nanocarbon is less likely to be destroyed. . That is, in the atmosphere, nanocarbon and oxygen in the atmosphere may cause a chemical reaction (combustion), that is, the generated nanocarbon is highly likely to be gasified or altered. Thus, preventing this reaction is very effective.
Further, if a sufficient shielding gas 12 is allowed to flow, the cathode deposit can be prevented from being deposited on the first electrode (cathode). If the shielding gas 12 is small, deposition may occur and the shape of the first electrode may be deformed. In this case, the arc discharge becomes unstable.

  Therefore, basically no container is required, but if you want to keep it in an inert gas or to prevent the effects of convection caused by wind, etc. The entire apparatus including the working unit may be placed in a simple container (a vacuum container or a pressurized container may be used. Alternatively, a sealed container or an open container may be used). Although the pressure in a container (envelope) is not specifically limited, From the surface of operativity, about atmospheric pressure is good. Here, “around atmospheric pressure” includes, for example, about 0.9 to 1.1 atmospheres (90 kPa to 110 kPa). Similarly, the atmosphere is generally a gaseous gas surrounding the main celestial body, and mainly refers to the earth. On the earth, it is a mixture that contains nitrogen and oxygen as main components and small amounts of carbon dioxide, neon, helium, methane, hydrogen, and so on. It also contains water vapor.

  In normal TIG welding, a W electrode containing thorium or a W electrode containing cerium is used for the torch electrode 10. In the production of nanocarbon, these electrodes may be used, but it is better to use pure graphite for the torch electrode 10 in order to avoid W fine particles adhering to the electron emission source. Moreover, you may use for the torch electrode the material which has refractory metals, such as Mo or Ni, as a main component. The diameter of the torch electrode 10 is not particularly limited, but is preferably about 1 to 7 mm in order to use a general-purpose torch.

  Furthermore, like the general-purpose TIG welding torch, the metal electrode holder 11 is desirably water-cooled. The torch that is the first electrode when the arc 4 is generated continuously (or intermittently) for a long time for the production of a large area nanocarbon substrate or for the continuous mass production of nanocarbon or nanocarbon substrate The electrode 10 and the electrode holder 11 will be heated too much. As a result, the consumption of the torch electrode 10 becomes intense, and the electrode holder 11 itself may be damaged. If the electrode holder 11 is cooled by flowing a gas 12 (specific gas) through the arc torch 1, the electrode holder 11 itself is not damaged by heating, and the torch electrode 10 is also cooled by the electrode holder 11. , Electrode consumption is suppressed.

As the arc current, direct current, direct current pulse, alternating current and alternating current pulse can be used, but direct current or direct current pulse is preferable in order to generate more soot 14.
When using direct current or direct current pulse, the temperature of the evaporation point is higher and the heating area is wider than when alternating current and alternating current pulse are used (cathode spots are alternately formed on the arced material 2). Evaporation is thriving. Therefore, it is more preferable to use a direct current or a direct current pulse for the arc current.
The value of the arc current can be used in a wide range of 5A to 500A. In order not to destroy the material to be arced, 30A to 300A are appropriate. 100 to 300A is more preferable for generating sufficient evaporation of the arced material at high speed.
When the arc is operated with a pulse current, the frequency is not limited, but 1 Hz to 500 Hz is appropriate from the viewpoint of the general-purpose power supply.

In the case of collecting soot, for example, a method of rotating a collecting plate serving as a base material and stripping it off with a scraper disposed at one place or a plurality of places of the rotation destination can be used. Here, even if the recovery plate is not rotated, the same applies to the forward and backward movement.
Furthermore, soot not only adheres to the recovery plate but also floats in the atmosphere (in the airtight container). Therefore, if the soot floating in the atmosphere is recovered using a suction device and a filter, the recovery rate can be further increased.

  A MIG (metal-electrode-inert-gas) torch or the like may be used instead of the TIG arc torch. Further, an apparatus (welding torch) having a structure similar to that of a TIG arc torch, for example, MAG (Metal-electrode-Active-Gas), plasma gouging (plasma cutting) can be used. Further, a thermal spraying torch (plasma spraying torch) or a blast furnace transfer arc torch may be used.

  The material to be arced 2 is mainly composed of graphite, and the shape and size thereof are not particularly limited. However, in order to facilitate evaporation of the material to be arced 2 and from the viewpoint of operability, a thin plate shape or a thin rod shape is preferable. . For example, when the arc current is about 30 to 300 A, the material 2 to be arced is preferably a thin plate or thin bar having a thickness of 1 to 3 mm and a width of about 10 mm. Furthermore, when using the material to be arced 2 having a thickness and a width, it is necessary to increase the arc current.

The arced material 2 containing a carbon material as a main component (that is, containing a large amount of carbon material) is a counter electrode of the torch electrode 10. As this carbon material, graphite, activated carbon, amorphous carbon, or the like can be used.
Further, in order to protect the arced material 2 from the heat of the arc 4 (that is, to reduce the possibility that the arced material 2 is destroyed by the heat of the arc 4), It is good to process on the water-cooled bench 3 which is the electrode stand made.

The material to be arced 2 may be well dried, but may contain moisture.
However, if the material to be arc 2 contains moisture, the energy of the arc 4 is absorbed by the evaporation of the moisture and it is difficult to raise the temperature of the evaporation location. Conversely, when the arced material 2 is wet, moist, contains moisture, or is in water, heating of the arced material 2 by the arc 4 can be prevented. Similarly, in order to prevent the arced material 2 from being heated, the arced material 2 can be directly water-cooled or oil-cooled. Further, a cooling medium such as water or carbon dioxide gas can be sprayed or sprayed on the arced material 2.

The material to be arced 2 may be pure graphite, but is preferably an additive that promotes evaporation and an additive that serves as a catalyst for nano-sizing soot and graphite that evaporates simultaneously.
The additives include Li (lithium), B (boron), Mg (magnesium), Al (aluminum), Si (silicon), P (phosphorus), S (sulfur), K (potassium), and Ca (calcium). , Ti (titanium), V (vanadium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), Ga (gallium) , Ge (germanium), As (arsenic), Y (yttrium), Zr (zirconium), Nb (niobium), Mo (molybdenum), Rh (rhodium), Pd (palladium), In (indium), Sn (tin) , Sb (antimony), La (lanthanum), Hf (hafnium), Ta (tantalum), W (tungsten), Os (osmium), Pt (platinum), or oxides thereof Nitride or carbide or sulfide or chloride or sulfuric acid compound or nitric compound, or mixtures thereof can be used.

  The additive can be contained in or incorporated in the graphite. Further, the additive may be dispersed, applied, plated or coated on the surface of graphite. Furthermore, the additive may be placed on graphite or sandwiched between graphites. That is, the material to be arced 2 only needs to have a structure in which the graphite and the additive are simultaneously heated by the arc 4.

  In order to efficiently evaporate the material 2 to be arced, it is preferable to generate an arc discharge at the end (end portion or end face of the material) or hole portion (through hole) of a round bar, square bar, plate or the like. In addition, soot 14 is also generated when the arc 4 is irradiated toward a horizontal surface such as a plate (that is, a central portion of the plate or the like) other than the end of the arc-receiving material 2 or the like. However, in order to generate a larger amount, it is more preferable to irradiate the end of the arced material 2 or the like. On the contrary, when the arc 4 is irradiated toward the end other than the end of the arc material 2, a convex portion or a concave portion is formed on the arc material 2, and the convex portion (the convex portion formed by forming the concave portion). It is preferable to irradiate the arc 4 toward the

  FIG. 3A shows a structure in which the additive 22 is dispersed, coated, plated or coated on the surface of the graphite 21, or a structure in which an additive plate made of the additive 22 is placed on the graphite plate made of the graphite 21. ing. Similarly, FIG. 3B shows a structure in which the wire rod of the additive 22 is sandwiched between graphite plates made of graphite 21. FIG.

  When the graphite 21 and the additive 22 are heated at the same time, evaporation of the arced material 2 is promoted due to the difference in evaporation temperature. More specifically, since the evaporation temperature of the additive 22, such as Ni or Y, is lower than the sublimation temperature of the graphite 21, if Ni or Y fine particles are mixed in the graphite, they are contained inside the graphite 21. The surrounding graphite is also crushed because of the explosive evaporation. For this reason, atomization of the arc material 2 (evaporation of the arc material 2) is further promoted. Ni and Y aggregate in the cooling process to form fine particles, and the fine particles serve as a catalyst for growing single-walled carbon nanotubes.

  In order to generate a large amount of soot 14 from the end of the arc material 2 and deposit the soot 14 on the substrate, the angle formed by the arc torch 1 and the arc material 2 should be in the range of 45 to 135 degrees. .

Here, the angle formed by the arc torch 1 and the material to be arced 2 will be described.
FIG. 4 is a view showing the angle formed by the arc torch 1 and the arc-target material 2.
As shown in FIG. 4, first, a substantially central axis of the torch electrode 10 of the arc torch 1 is a straight line A. Next, when the arced material 2 is a linear member, for example, a wire rod whose cross-sectional shape is composed of a cylinder or a prism, the substantially central axis of the linear member is a straight line B. In this case, it means an angle formed by the straight line A and the straight line B (90 degrees in FIG. 4).
Similarly, when the material 2 to be arced is a plate-like member, for example, a rectangular parallelepiped, any one of the X-axis, Y-axis, and Z-axis of the rectangular parallelepiped corresponds to the straight line B.

As shown in FIG. 5, when the arc torch 1 and the material to be arced 2 are arranged linearly (180 degrees), the discharge direction of the soot 14 extends over a wide range.
This is because the arc spot (the arc discharge location in the arced material 2) is not stable, and the soot 14 is discharged in various directions, front and rear, left and right. In this case, a plurality of substrates (one in the case of a cylindrical substrate) may be arranged so that the substrate is opposed to the arc discharge region and surrounds the expected soot 14 discharge direction.

  The apparatus shown in FIG. 5 is provided with a covering member 15 that also functions as a base material, instead of the base material of the apparatus shown in FIG. The covering member 15 is an open container made of glass, ceramics, metal or the like. The covering member 15 has a cylindrical or prismatic shape with the upper and lower surfaces open so as to surround the torch electrode 10 of the arc torch 1, the material to be arced 2, and the arc 4. Thereby, the cleanliness of the work place can be maintained, or the influence of convection caused by wind or the like can be prevented. Further, if the covering member 15 is used as an airtight container and the arc torch 1, the material to be arced 2, and the arc 4 are contained, arc discharge can be performed in an inert gas. Furthermore, it is possible to put the entire apparatus in this hermetic container.

  Here, the covering member 15 shown in FIG. 5 also functions as a substrate which is a base material (collecting member) on which the soot 14 is deposited. That is, it is arranged so as to surround a region where the soot 14 scatters and has a size sufficient for the soot 14 to be deposited. With such a configuration, the components of the apparatus can be reduced. Of course, the substrate and the covering member can be provided separately. Needless to say, the covering member 15 can be applied to other embodiments such as FIG. 1 and FIG.

The distance between the arc torch 1 and the material to be arced 2 is suitably 0.1 to 10 mm.
Moreover, 1-50 mm is suitable for the distance of the to-be-arced material 2 and the board | substrate 3. As shown in FIG.
In FIG. 1, the arced material 2 and the substrate 3 are arranged substantially in parallel, but the angle formed by these is not limited, and may be vertical, for example.

  Even if the graphite of the arc material 2 evaporates, if a means for holding the arc material 2 so as to be movable in a predetermined direction is provided, the arc material 2 and the arc torch are selected depending on the degree of graphite evaporation. It is possible to adjust the distance from one torch electrode 10. Of course, a means for holding the torch electrode 10 in a predetermined direction or holding both the torch electrode 10 and the arced material 2 movably may be provided. This makes it possible to maintain optimum manufacturing conditions.

Further, when the graphite of the arc material 2 evaporates and the end of the arc material 2 or the shape of the protruding portion of the arc material 2 is deformed, it is moved to another end or the end is linear. Alternatively, in the case of a planar shape, by providing means for holding one or both of the torch electrode 10 and the arc-treated material 2 so as to be movable in a predetermined direction along the same, optimum manufacturing conditions are similarly maintained. And so on.
Furthermore, it is better to combine the above two movement methods.

Then, the relative movement between the arc torch 1 and the material to be arced 2 may be performed manually (manual hand), or the arc torch 1 is moved in three directions (that is, a plane parallel to the material to be arced 2 (X direction). And the Y direction) and a direction perpendicular to the surface (Z direction) may be used automatically.
In particular, if an NC device (numerical control device) or the like is used, for example, the end of the material to be arced 2 (the end portion or end surface of the material) or the concave portion, the hole portion (through hole) or the convex portion, etc. It becomes possible to irradiate the part with the arc 4.

  According to the manufacturing method of the present invention, nanocarbon or soot containing nanocarbon (composite material containing nanocarbon) is obtained by sequentially replacing the substrate 3 while adjusting the distance and position between the torch electrode 10 and the arced material 2. Can be produced continuously. In addition, the substrate 3 is continuously disposed, and the carbon is continuously moved along the substrate 3 group while adjusting the distance between the torch electrode 10 and the arced material 2, so that the nanocarbon or the soot containing nanocarbon is continuously formed. Production becomes possible. Furthermore, when the substrate 3 has a large area, a large-area nanotube base material can be manufactured by adjusting the distance and position between the torch electrode 10 and the arced material 2 or moving the substrate 3 itself.

In the above manufacturing method, when air or nitrogen is used as the gas flowing through the arc torch 1, nanocarbon containing N, that is, so-called CN nanotube can be formed. In addition, graphite containing a material containing B, graphite containing a metal catalyst (additive), etc., or graphite containing B containing material, or a material containing B, or an additive as an arced electrode When graphite coated with, coated, plated or coated with a material containing is used, nanocarbon containing a BCN network, so-called BCN nanotubes, can be formed. Similarly, various nanocarbons can be formed by changing the atmosphere gas and additives. Here, B represents boron, C represents carbon, and N represents nitrogen.
Moreover, in the electron emission source containing nanocarbon manufactured by the above method, the performance of the electron emission source is improved by oxidizing and removing nanoparticles that inhibit electron emission.

As shown in FIG. 6, the discharge direction of the soot 14 can be controlled by adjusting the angle between the arc torch 1 and the material 2 to be arced as described above.
That is, when the arc torch 1 is tilted in the direction indicated by the dotted arrow in the figure, the deposition position of the soot 14 deposited on the substrate 3 can be changed according to the magnitude of the tilt. Here, the discharging direction of the soot 14 indicates a region where the soot 14 is most likely to be deposited on the substrate 3 (the soot 14 is deposited most thickly).
Similar control is possible by adjusting the angle formed by the arc 4 and the substrate 3.

The apparatus shown in FIG. 6 includes, in addition to the base material shown in FIG. 1, a fluid (liquid) 16 composed of natural water, silicone oil, oil (fluid oil below the arc discharge temperature), and the fluid 16. A container 17 of fluid that is housed and is an open container made of glass, ceramics, metal or the like is disposed in an area where the soot 14 is scattered. The fluid container 17 further accommodates the substrate 3 in the fluid 16 accommodated therein.
In addition to the above, a low-temperature refrigerant such as an aqueous solution, dry ice, liquid nitrogen, or liquid helium can be used as the fluid.

  Further, the fluid container 17 is a cylindrical or prismatic container having an open upper surface so as to surround the arc 4. This also serves as a covering member that keeps the work place clean or prevents the influence of convection caused by wind or the like. That is, it is arranged so as to cover the area where the soot 14 scatters, and has a size sufficient for the soot 14 to be deposited. With such a configuration, the components of the apparatus can be reduced. Of course, this substrate is not necessarily required when nanocarbon is produced without patterning the nanocarbon.

Further, in this case, heat-resistant fine particles such as sand, glass, ceramic, and metal (collectively referred to as granular materials) are possible even if they are not fluids. Furthermore, a mixture of the fluid (liquid) and the heat-resistant fine particles may be used. In this case, the container 17 is a granular container or a fluid and granular container.
Needless to say, the fluid container 17 and the like can be applied to other embodiments such as FIG. 1 and FIG.

Here, the substrate 3 is removed from the fluid container, and the fluid container 17 is a container having a closed system flow path through which the fluid 16 circulates. And the filtration member etc. which have the function to collect | recover the soot 14 containing nanocarbon are provided in the middle of the flow path. With such a configuration, the soot 14 can be continuously collected, and a simpler manufacturing method and an apparatus used therefor can be provided.
Of course, the substrate 3 may not be installed, and after attaching or depositing soot on the fluid surface, the fluid may be selected and filtered to extract and select a predetermined nanocarbon material.

  According to the manufacturing method of the present invention, nanocarbon or soot containing nanocarbon (composite material containing nanocarbon) is obtained by sequentially replacing the substrate 3 while adjusting the distance and position between the torch electrode 10 and the arced material 2. Can be produced continuously. In addition, the substrate 3 is continuously disposed, and the carbon is continuously moved along the substrate 3 group while adjusting the distance between the torch electrode 10 and the arced material 2, so that the nanocarbon or the soot containing nanocarbon is continuously formed. Production becomes possible. Furthermore, when the substrate 3 has a large area, a large-area nanotube base material can be manufactured by adjusting the distance and position between the torch electrode 10 and the arced material 2 or moving the substrate 3 itself.

  FIG. 7 shows an example of a method for forming the electron emission surface in a pattern on the substrate 3. In this case, the mask 13 is set on the substrate 3 and the soot 14 is deposited thereon. If the mask 13 is removed, an electron emission surface having the same pattern as the mask 13 is obtained. At this time, if an electrode or the like corresponding to the opening of the mask is provided on the substrate 3, it can be used as a cathode electrode or the like. Further, if the substrate 3 is an insulator and wiring is provided on each island of the pattern, electrons can be emitted independently from each island. This is a production method useful when manufacturing a panel-type display.

  Note that the mask 13 may be installed above the substrate 3 (a space between the arced material 2 and the substrate 3). When the mask 13 is disposed in the vicinity of the arc 4, a material that can withstand the high temperature and thermal shock of the arc, such as a refractory metal, ceramics, or graphite, is used.

Similarly, the substrate 3 to be used is not limited. An adhesive layer 23 may be provided on the substrate 3 in order to improve the adhesion between the substrate 3 and the soot 14 deposited on the surface, or to improve the electrical characteristics between the substrate 3 and the soot 14. . Moreover, in order to protect the board | substrate 3 from the heat | fever of the arc 4, you may cool the board | substrate 3 at the time of manufacture.
Since cooling the substrate 3 can reduce the possibility of the substrate being broken (cracked) by heat, it is preferable to add a means for cooling the substrate 3 at the time of manufacture and cool the substrate 3. preferable.

In the case of an AC arc or AC pulsed arc, sprayed, coated, plated, coated (evaporated) or injected with graphite containing a material containing pure graphite, an additive, etc., or an additive, etc. Graphite can be used.
On the other hand, in the case of direct current arc or direct current pulse arc, pure graphite cannot be used. However, graphite containing a material containing an additive or the like, or a material containing an additive or the like is dispersed, applied, plated, coated (evaporated) or Injected graphite can be used.

  FIGS. 8A to 8C show an example of a method that can be applied when the adhesion between the substrate 3 and the soot (nanocarbon) 14 is poor. FIG. 8A to FIG. 8C are modifications of the method described in FIG. 7 and are different only in that an adhesive layer 23 is provided on the substrate 3.

In this method, first, a patterned adhesive layer 23 is formed on the substrate 3 as shown in FIG. Various methods such as screen printing can be used to form the adhesive layer 23. In addition, as a material for the adhesive layer 23, a conductive paste such as an Al paste or a conductive C paste can be used.
Next, as shown in FIG. 8B, soot (nanocarbon) 14 is deposited by the apparatus shown in FIG. 7 before the adhesive layer 23 is cured.

Thereafter, the adhesive layer 23 is cured. When the adhesive layer 23 is cured, the soot 14 deposited on the adhesive layer 23 is in close contact with the adhesive layer 23.
Finally, if the entire substrate 3 is washed (for example, washed with water), the soot 14 deposited on the substrate 3 is removed, and the soot 14 deposited on the adhesive layer 23 is formed into a pattern as shown in FIG. It is formed.
The adhesive layer 23 can be used as a cathode electrode or a cathode wiring when used as an electron emission source.

As a method of using the nanocarbon electron emission source manufactured by the manufacturing method of the present invention, a conventional diode method or triode method can be used.
Particularly, it is suitable for a display tube, a display panel, a light emitting element, a light emitting tube, a light emitting panel and the like.
Furthermore, by emitting electrons from the nanocarbon generated at a specific location, it can be applied to a display device having a complicated pattern.

  Nanocarbon produced by the production method of the present invention, or composite soot of nanocarbon and metal fine particles can be suitably used as a hydrogen storage material.

An example of specific experimental results is shown below.
FIG. 9 is a photograph of an electron emission source manufactured in the form of a TUT string using the apparatus of FIGS. 1 and 7.
The substrate serving as the base material is conductive Si. A graphite plate containing Ni / Y (Ni and Y content: 4.2 and 1.0 mol%, plate thickness: 2 mm, width 5 mm) was used as the arc-treated material, and the atmosphere was open (atmospheric pressure) with a direct current of 100 A. (Below).

  Note that substantially the same results were obtained when activated carbon, amorphous carbon, or graphite containing a catalytic metal was used instead of the graphite plate. In addition, when a specific gas, particularly a rare gas, was used, the yield of the produced nanocarbon increased. From this, it was confirmed that the use of a rare gas is very effective.

  A scanning electron micrograph of the deposit is shown in FIG. It can be seen that the nano-sized structures are dispersed all over. This deposit contained single-walled carbon nanotubes, nanohorns, and the like as shown in FIG. Here, the nanohorn is a carbon nanoparticle having a shape obtained by rolling a graphite sheet into a conical shape, and the tip is also closed in a conical shape (Pore structure of single-wall carbon nanohorn aggregates / K. Murata, K Kaneko, F. Kokai, K. Takahashi, M. Yudasaka, S. Iijima / Chem. Phys. Lett., Vol. 331, pp. 14-20 (2000) ”).

  When the sample was used to emit electrons with a fluorescent tube having a bipolar structure, and the phosphor screen was irradiated, it was visually observed that the phosphor screen emitted light. Here, the results when using activated carbon, amorphous carbon, or graphite containing an additive instead of the graphite plate, and the effects when using a specific gas were the same as in FIG.

  In each of the above-described embodiments, an example in which nanocarbon on the base material (substrate 3) is used as it is, but separated and recovered from the base material (substrate 3) as a composite of nanocarbon and metal fine particles. Of course, it can be used. Furthermore, it is of course possible to refine the soot and use it as nanocarbon such as a single nanotube.

FIGS. 12 to 14 show the soot produced by using the apparatus shown in FIG. 1 and observed from the base material (substrate 3) with a transmission electron microscope.
FIG. 12 was taken at a low magnification. In FIG. 12, the light-colored portions are carbon materials, and the dark portions are metal fine particles, which are mixed and condensed. It can be seen that a bundle of needle-like single-walled nanotubes protrudes from the end of the condensate.

FIG. 13 shows another field of view observed at a high magnification. FIG. 13 shows that single-walled carbon nanotubes are formed in a bundle. Single-walled carbon nanotubes are grown using metal fine particles as a catalyst.
FIG. 14 shows another field of view observed at a high magnification. In FIG. 14, it can be seen that carbon nanohorns exist.

  The components of the samples shown in FIGS. 12 to 14 contain approximately 70 to 80 mol% carbon, 2 to 10 mol% oxygen, 1 to 5 mol% yttrium (Y), and 4 to 20 mol% nickel (Ni). It is. Moreover, 1-30 mol% is a single-walled nanotube, and 0.1-5 mol% is a nanohorn. Furthermore, 0.1-5 mol% multi-walled nanotubes were also observed. The remaining carbon components are carbon nanoparticles and amorphous carbon.

  Nanocarbon produced by the production method of the present invention or composite soot (composite material) containing nanocarbon and metal fine particles can be used as an occlusion material such as hydrogen. The hydrogen storage rate of soot shown in FIGS. 12 to 14 was measured by a capacity method and found to be 1 to 10 wt% at room temperature of 30 atm. Moreover, it was 0.1-1 wt% in normal temperature normal pressure. More values are expected by optimizing the manufacturing conditions. For this reason, the soot containing nanocarbon produced by the production method of the present invention is suitable for an occlusion body such as hydrogen. In addition, the amorphous carbon fine particles also have a space in which hydrogen can be occluded. Moreover, since metal components, such as Ni and Y, are also hydrogen occluding, it is suitable for occlusion bodies, such as hydrogen. Therefore, it is not always necessary to separate nanocarbon from the soot.

Nanocarbon produced by the production method of the present invention is characterized in that soot contains multi-walled carbon nanotubes, carbon nanohorns, carbon nanoparticle, amorphous carbon, and fullerene as well as single-walled nanotubes. For this reason, if the operation | work which isolate | separates nanocarbon from this soot is performed, it can be utilized as nanocarbon which consists of one type or multiple types.
Here, in order to separate and purify nanocarbon from soot, it is necessary to remove large particles by sieving, centrifugation, removal of amorphous components by superheat oxidation, removal of metal components by acid, alkali, aqua regia, reverse aqua regia, etc. A method is available.

  Multi-walled carbon nanotubes exist when graphite is used for the torch electrode. This is because the multi-walled carbon nanotubes synthesized on the surface of the graphite torch electrode are blown off and mixed into the soot. CN nanotubes, CN nanofibers, and CN nanoparticles are produced by using nitrogen as a shielding gas. BCN nanotubes, BCN nanofibers, and BCN nanoparticles are also produced by putting B in a carbon electrode and using nitrogen as a shielding gas. Soot is a mixture of multiple types of nanocarbons.

In addition, for composites or mixed soot (composite or mixed material) containing nanocarbon and metal fine particles (composite or mixed material), it is not only the metal that is added (coated) as an additive, so strictly speaking, an additive containing metal fine particles Fine particles.
The size of the metal particulates is about 1 nm to typically 1 μm (up to 10 μm original additive size). The material is an additive composition and its carbide. The metal fine particles are generated by melting, evaporating, or forming fine particles due to the high temperature of the arc and aggregating in the cooling process. In the case of a single additive, the metal fine particles exist in a simple substance or carbide state. In the case of a plurality of additives, they exist in the form of simple substances, alloys and carbides thereof.

  FIG. 15 is a diagram showing an apparatus for measuring the electron emission characteristics of the electron emission source. Electron emission characteristics of an electron emission source (electron emission device) using soot 14 containing nanocarbon and metal fine particles as an electron emission material and a conventional electron emission source using single-walled carbon nanotubes as an electron emission material were measured. It is for comparison. In FIG. 15, a substrate (cathode substrate) 3 and an anode substrate 103 are disposed facing each other in a vacuum chamber 100. On the substrate 3, a cathode electrode 101 and soot 14 layers (emitter layers) are laminated. On the anode substrate 103, an anode electrode (also a lead electrode) 102 is formed. The distance between the substrate 3 and the anode substrate 103 is set to 100 μm. A DC power source 104 and an ammeter 105 are connected in series between the cathode electrode 101 and the anode electrode 102.

  FIG. 16 shows the electron emission characteristics of an electron emission source using soot 14 containing nanocarbon and metal fine particles as an electron emission material using the measurement apparatus of FIG. 15, and electron emission of single-walled carbon nanotubes instead of soot 14. It is the data which compared the electron emission characteristic of the electron emission source used as material. Here, the single-walled carbon nanotube is manufactured by a conventional vacuum arc discharge method. As shown in FIG. 16, the electron emission source using soot 14 (nanocarbon) manufactured in the atmosphere is earlier than the electron emission source using single-walled carbon nanotubes manufactured in the conventional vacuum. It can be seen that the rising characteristics are not inferior and show almost the same electron emission characteristics.

The nanocarbon produced by the production method of the present invention can be used for a mixture to a secondary battery electrode, a secondary battery electrode, a mixture to a fuel cell electrode, and a secondary battery electrode.
The nanocarbon produced by the production method of the present invention can be used as a mixture with rubber, plastic, resin, ceramics, steel, concrete and the like. By mixing the nanocarbon with these materials, strength, thermal conductivity, electrical conductivity, and the like can be improved.

  In each of the above embodiments, a flat plate is used as the shape of the base material (substrate 3), but a columnar shape such as a columnar shape or a prismatic shape or a spherical shape may be used.

Similarly, in each of the above embodiments, a conductive Si material (conductive substrate) is used as the material of the base material (substrate 3). However, an insulating substrate such as glass or ceramic, or the surface of the conductive substrate is insulated. It is also possible to use an insulating substrate on which a film is formed, a conductive substrate such as a metal, or a conductive substrate on which the conductive film is formed on the surface of the insulating substrate.
In addition to the substrate, a flexible member such as a film can be used.
Furthermore, when it arrange | positions in the vicinity of the generation | occurrence | production area | region of arc discharge, it is necessary to use the base material provided with heat resistance.

It is a figure which shows the outline of the manufacturing apparatus of nanocarbon (composite soot of nanocarbon and metal microparticles). It is a partial expanded sectional view of the nanocarbon manufacturing apparatus of FIG. It is a figure which shows the modification which added the additive to the to-be-arced material (2nd electrode). It is a figure which shows the angle which the arc torch 1 and the to-be-arced material 2 make. It is a figure which shows the case where the arc torch 1 and the to-be-arced material 2 are arrange | positioned at linear form (180 degrees). It is a figure which shows controlling the discharge | release direction of soot 14 by adjusting the angle of the arc torch 1 and the to-be-arced material 2. FIG. It is a figure which shows an example of the method of forming nanocarbon in a specific location (patterning). It is a figure which shows the other example of the method of forming nanocarbon in a specific location (patterning). It is a figure which shows the patterned electron emission source (TUT character string) produced using the method of FIG. It is a figure which shows the state of the surface (surface of a deposit) of the patterned electron emission source created in FIG. It is a figure which shows the single-walled carbon nanotube which exists in the patterned electron emission source (sediment) of FIG. It is a TEM photograph (low-magnification photograph) of the soot manufactured using the apparatus shown in FIG. 2 is a TEM photograph (high magnification photograph) of soot (composite of single-walled nanotubes and metal fine particles) produced using the apparatus shown in FIG. 1. It is a TEM photograph (high magnification photograph) of the soot (nanohorn) manufactured using the apparatus shown in FIG. It is the schematic of the apparatus which measures the electron emission characteristic of the electron emission source which concerns on the Example of this invention. It is a figure which shows the electron emission characteristic of the electron emission source which concerns on the Example of this invention.

Explanation of symbols

1 ... arc torch,
2 ... Arc material,
3 ... substrate,
4 ... Ark,
5 ... Power supply,
6 ... Gas cylinder,
7 ... Gas regulator and flow meter,
8 ... The tip of the arc torch,
9 ... Arc torch nozzle,
10 ... torch electrode,
11 ... Electrode holder,
12 ... Encapsulated gas,
13 ... Mask,
14 ... Accumulated soot (nanocarbon),
15 ... covering member,
16 ... fluid (liquid),
17 ... Fluid / granular container (fluid / granular container)
21 ... graphite,
22 ... additives,
23. Adhesive layer,
100 ... Vacuum chamber,
101 ... cathode electrode,
102 ... anode electrode,
103 ... anode substrate,
104: DC power supply,
105: Ammeter.

Claims (10)

A step of opposingly arranging the first electrode and the second electrode mainly composed of a carbon material;
A step of generating an arc discharge by applying a voltage between the first electrode and the second electrode in the air or in the air or in a gas atmosphere;
Evaporating the carbon material of the second electrode by the arc discharge to generate soot containing nanocarbon;
A step of collecting the soot containing nanocarbon,
A method for producing nanocarbon, comprising control means for controlling the soot discharge direction. A step of opposingly arranging the first electrode and the second electrode mainly composed of a carbon material;
A step of generating an arc discharge by applying a voltage between the first electrode and the second electrode in the air or in the air or in a gas atmosphere;
Evaporating the carbon material of the second electrode by the arc discharge to generate soot containing nanocarbon;
A step of collecting the soot containing nanocarbon,
A method for producing nanocarbon, characterized in that a discharge direction of the soot is controlled by supplying a specific gas or air to a region where the arc discharge is generated. A step of opposingly arranging the first electrode and the second electrode mainly composed of a carbon material;
A step of generating an arc discharge by applying a voltage between the first electrode and the second electrode in the air or in the air or in a gas atmosphere;
Evaporating the carbon material of the second electrode by the arc discharge to generate soot containing nanocarbon;
A step of collecting the soot containing nanocarbon,
A method for producing nanocarbon, wherein the soot discharge direction is controlled by adjusting an angle formed by the first electrode and the second electrode in a range of 45 degrees to 135 degrees.   The carbon material of the second electrode is a carbon material containing or containing an additive, or a carbon material in which the additive is dispersed, applied, plated or coated on a part or all of the surface. The method for producing nanocarbon according to claim 3.   The method for producing nanocarbon according to claim 3, wherein the arc discharge is performed while supplying a specific gas or air to a region where the arc discharge is generated.   The method for producing nanocarbon according to claim 2 or 5, wherein the arc discharge is performed while supplying the specific gas or the air from the first electrode side to the generation region of the arc discharge.   The first electrode is a torch electrode provided in an arc torch, and a specific gas or air is supplied to the arc torch while moving the torch electrode and the second electrode relative to each other to generate the arc discharge 6. The nano of claim 2 or 5, comprising a step of generating soot containing nanocarbon by evaporating the carbon material of the second electrode by the arc discharge while supplying a specific gas or the air. Carbon manufacturing method. An electrode comprising a first electrode and a carbon material containing a carbon material or an additive, or a second electrode mainly composed of a carbon material on which a carbon material or additive is formed on the surface;
A voltage is applied between the first electrode and the second electrode in the air, air, or gas atmosphere to generate an arc discharge, and the carbon material is evaporated by the arc discharge to include nanocarbon. Arc generating means comprising a power source for generating soot;
A collecting member for collecting the soot;
An apparatus for producing nanocarbon, comprising control means for controlling the soot discharge direction. An electrode comprising a first electrode and a carbon material containing a carbon material or an additive, or a second electrode mainly composed of a carbon material on which a carbon material or additive is formed on the surface;
A voltage is applied between the first electrode and the second electrode in the air, air, or gas atmosphere to generate an arc discharge, and the carbon material is evaporated by the arc discharge to include nanocarbon. Arc generating means comprising a power source for generating soot;
A collecting member for collecting the soot;
An apparatus for producing nanocarbon, comprising: a specific gas supply means for supplying a specific gas to the arc discharge generation region in order to control the soot discharge direction. An electrode comprising a first electrode and a carbon material containing a carbon material or an additive, or a second electrode mainly composed of a carbon material on which a carbon material or additive is formed on the surface;
A voltage is applied between the first electrode and the second electrode in the air, air, or gas atmosphere to generate an arc discharge, and the carbon material is evaporated by the arc discharge to include nanocarbon. Arc generating means comprising a power source for generating soot;
A collecting member for collecting the soot;
An apparatus for producing nanocarbon, comprising means for adjusting an angle formed by the first electrode and the second electrode in a range of 45 degrees to 135 degrees.

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