WO2004113225A1

WO2004113225A1 - Nanocarbon-producing device

Info

Publication number: WO2004113225A1
Application number: PCT/JP2004/008743
Authority: WO
Inventors: Takeshi Azami; Tsutomu Yoshitake; Yoshimi Kubo; Daisuke Kasuya; Sumio Iijima; Masako Yudasaka
Original assignee: Nec Corporation
Priority date: 2003-06-24
Filing date: 2004-06-22
Publication date: 2004-12-29
Also published as: US20070025905A1; CN1812931A; TWI270528B; CN100424008C; TW200524825A; JPWO2004113225A1

Abstract

In a nanocarbon-producing device (173), a plane mirror (169) and a parabolic mirror (171) are arranged in a production chamber (107). Light, emitted from a laser light source (111), transmitted through a ZnSe window (133) is reflected at the plane mirror (169) and the parabolic mirror (171), collected at the parabolic mirror (171), and then irradiated onto the surface of a graphite rod (101).

Description

Specification

Nano carbon production equipment

Technical field

The present invention relates to an apparatus for producing nanocarbon.

Background art

[0002] In recent years, engineering applications of nanocarbon have been actively studied. Nanocarbon refers to a carbon material having a nanoscale microstructure, such as carbon nanotubes and carbon nanohorns. Among them, the carbon nanohorn has a tubular body structure in which one end of a carbon nanotube in which a graphite sheet is rolled into a cylindrical shape has a conical shape. Normally, the carbon nanohorns are aggregated in a form of cones protruding from the surface like corners (horns) around the tube by van der Phanoresca working between the conical parts, forming a carbon nanohorn aggregate. The carbon nanohorn aggregate is expected to be applied to various technical fields due to its unique properties.

[0003] The carbon nanohorn aggregate may be manufactured by a laser evaporation method in which a carbon material (hereinafter, also referred to as "Daraphyte target") is irradiated with laser light in an inert gas atmosphere. It has been reported (Patent Document 1). Patent Document 1 exemplifies a CO gas laser as a laser beam.

By the way, the wavelength of a C〇 gas laser is about 10.6 μm, and ZnSe or the like is suitably used as a material that transmits a CO gas laser (Patent Document 2). Therefore, it is thought that when a carbon nanohorn aggregate is manufactured using a CO gas laser, laser light can be focused on the graphite target surface by using a ZnSe lens.

Patent Document 1: Japanese Patent Application Laid-Open No. 2001-64004

Patent Document 2: JP 2001-51191 A

[0006] Disclosure of the Invention

[0007] Therefore, the present invention examined a method of manufacturing a carbon nanohorn aggregate by providing a window made of ZnSe (hereinafter also referred to as a "laser light window") in a manufacturing chamber. Then, as the operating time of the laser-light window becomes longer, the carbon nanotubes in the soot-like material collected It was found that the weight ratio (hereinafter, referred to as “yield”) of the Nohorn assembly was reduced. In addition, the lifetime of the laser-light window may be relatively short, and the window may be damaged. As a result, it was found that the maintenance of the equipment was costly and the life of the equipment itself was shortened. The life of the ZnSe lens provided outside the chamber was also relatively short.

[0008] Therefore, the cause of the decrease in the yield of the carbon nanohorn aggregate and the cause of the short life of the laser window or lens were examined. As a result, when the graphite target is irradiated with laser light, these factors may be that soot-like substances generated from carbon vapor generated from the graphite target adhere to the surface of the laser light window. Was found. It has also been found that when soot-like substances adhere to the surface of the laser window or lens, light is absorbed in the attached area and the laser window or lens is heated.

In such a case, the optical path may be shifted due to the thermal lens effect. The deviation of the optical path may be caused by the displacement of the position where the Co gas laser is

Two

The power density of the irradiated light can be a factor of the change. This was presumed to be the cause of the decrease in the yield due to the increase in the operation time of the equipment. In addition, it was speculated that heating of the laser light window and the lens could cause damage. For this reason, there has been a need for a technique for producing a carbon nanohorn aggregate without reducing the yield. Also, in order to prolong the life of the device, a different technology is required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique for obtaining nanocarbon with high efficiency and stability. Another object of the present invention is to provide a technique for extending the life of a nano-carbon manufacturing apparatus.

[0011] The present inventors diligently studied a technique for obtaining nanocarbon with high efficiency.

As a result, they found that it is important to shield the optical member from the adhesion of soot-like substances when irradiating the light emitted from the light source to the surface of the graphite target using the optical member, and reached the present invention. In addition, the optical member is protected from soot-like substances by irradiating the graphite target after changing the optical path by reflecting the light emitted from the light source without directly irradiating the surface of the graphite target. And arrived at the present invention.

According to the present invention, a graphite target and a chamber for accommodating the graphite target A window provided in a part of the chamber; a light source for irradiating light to the surface of the graphite target through the window; and a carbon vapor evaporated from the graphite target by the irradiation of the light. An apparatus for producing a nanocarbon, comprising: a recovery unit for recovering nanocarbon generated by the method; and a shielding member interposed between the window and the Dalaphite target.

In the present invention, a shielding member is provided between the window and the graphite target. As described above, if the light emitted from the light source passes through the window and is directly irradiated on the surface of the graphite target, the soot-like substance obtained from the carbon vapor generated from the surface of the graphite target becomes However, since it also scatters in the direction returning to the window, the soot-like substance easily adheres to the surface of the window. Therefore, when the optical member made of ZnSe was used, the optical member was easily heated.

[0014] On the other hand, the configuration of the present invention has a configuration in which the window is shielded from the surface of the graphite target. With this configuration, even when the soot-like substance generated from the graphite target surface scatters toward the window, the soot-like substance moves toward the window because the shielding member shields the soot-like substance. Adhesion to the surface is suppressed. For this reason, the power density of the light irradiated to the graphite target can be stabilized, and nanocarbons having desired properties can be stably produced with a high yield.

[0015] In the present invention, the shielding member is disposed so as to cover the carbon vapor power window evaporated from the graphite target. The shielding member covers the window so as to prevent the light emitted from the light source from reaching the surface of the graphite target and to prevent soot-like substances obtained from carbon vapor generated from the surface of the graphite target from attaching thereto. can do.

[0016] In the present invention, the chamber houses a graphite target. However, it is not necessary to accommodate the entire graph item target. It may contain part of a graphite target.

In the present invention, the window is an optical member that transmits light emitted from a light source, and may be, for example, a laser light window or a lens. In addition, the window is arranged such that a part thereof is exposed to the room. The window is located on the emission end face etc. as part of the light source It may be placed on a wall or the like of a room in which the graphite target is housed as a member independent of the light source.

[0018] In this specification, the "power density" refers to the power density of light actually applied to the surface of the graphite target, that is, the power density at the light irradiation site on the surface of the graphite target. I do.

In the manufacturing apparatus of the present invention, an optical member for guiding the light to the surface of the graphite target may be provided between the window and the shielding member. By doing so, it is possible to reliably irradiate the surface of the graphite target with light. Therefore, nano force can be stably manufactured. Further, in the present invention, since the shielding member is provided between the optical member and the Dalaphite target, the soot-like substance is scattered toward the window portion without being collected by the collection part, and adheres to the surface of the optical member. Can be suppressed. For this reason, the displacement of the laser irradiation position on the surface of the graphite target due to the thermal lens effect and the fluctuation of the power density of light on the surface can be suppressed. Therefore

Therefore, it is possible to stably produce nanocarbon having desired properties. Therefore, the yield of nanocarbon can be improved. Further, since heating of the optical member is suppressed, breakage of the optical member can be suppressed, and the life of the optical member can be extended. Further, it is possible to suppress an increase in maintenance cost of the apparatus due to replacement of the optical member. Therefore, an apparatus configuration excellent in durability and productivity can be easily realized.

According to the present invention, a graphite target, a chamber for accommodating the graphite target, a window provided in a part of the chamber, and a surface of the graphite target via the window are provided. A light source for irradiating light, a recovery unit for recovering nanocarbon generated from carbon vapor evaporated from the graphite target by the irradiation of the light, and a reflecting unit for reflecting the transmitted light transmitted through the window, And a reflecting member for guiding to the surface of the nanocarbon.

Further, in the nanocarbon manufacturing apparatus of the present invention, the optical member may include a reflecting member.

[0022] By doing so, it is possible to irradiate the surface of the graphite target after changing the optical path of the light transmitted through the window. Therefore, adhesion of soot-like substances to the window can be reliably suppressed. Can be.

In the present invention, for example, the surface of the reflection member can be made of metal. By doing so, the heat radiation of the surface is suitably secured. Therefore, even if soot-like substances adhere to the surface, an excessive rise in temperature can be suppressed. In the present invention, a cooling mechanism for cooling the reflection member may be further provided. This makes it possible to more reliably cool the reflecting member. For this reason, it is possible to suppress overheating of the reflection member and improve the life thereof. Further, nanocarbon can be stably produced. Further, in the present invention, a dust cleaning mechanism for removing soot-like substances attached to the reflection member may be further provided. In this way, it is possible to produce nanocarbon while removing soot-like substances at a predetermined timing. For this reason, the yield of nanocarbon can be further improved.

[0024] The apparatus for producing nanocarbon of the present invention may further include a shielding member interposed between the reflection member and the graphite target.

By doing so, it is possible to more reliably protect the window or the optical member from the adhesion of soot-like substances. For this reason, a decrease in the yield of nanocarbon can be suppressed. Further, the life of the optical member can be extended.

[0026] In the nanocarbon manufacturing apparatus of the present invention, the reflection member may have a light-collecting action. By doing so, it is possible to reliably condense light at a predetermined position on the graphite target. For this reason, nanocarbon can be manufactured stably. Further, since light can be focused on the surface of the graphite target without providing an optical member for focusing, nanocarbon can be efficiently produced with a simple configuration. The reflecting member having the light-condensing action may be constituted by a single member, or may be constituted by a combination of a plurality of members.

For example, the reflecting member can be a concave mirror. Further, in the nanocarbon manufacturing apparatus of the present invention, the reflecting member may be a parabolic mirror. In this way, the reflected light reflected by the concave mirror can be surely focused at the focal point. Therefore, the reflected light can be more reliably focused on the surface of the graphite target. Therefore, nanocarbon can be produced more stably.

[0028] In the nanocarbon production apparatus of the present invention, the cylindrical graphite target is It is possible to provide a target holding means for holding and rotating the graphite target about a central axis. By doing so, nanocarbon can be produced continuously. Therefore, the yield of nanocarbon can be improved.

[0029] In the nanocarbon production apparatus of the present invention, the nanocarbon may be a carbon nanohorn aggregate.

[0030] By doing so, a carbon nanohorn aggregate can be stably produced with a high yield.

[0031] The apparatus for producing nanocarbon of the present invention may further include an air suction unit that generates an airflow along the traveling direction of the light from the light source side toward the graphite target side. By doing so, it is possible to more reliably suppress the soot-like substance from moving from the graphite target side to the light source side and adhering to the window or the optical member. For this reason, the life of the device can be more reliably prolonged. In addition, nanocarbon can be produced more stably.

[0032] The forces described above for the configurations of the present invention are also effective as embodiments of the present invention. Further, the expression of the present invention converted into another category is also effective as an embodiment of the present invention.

As described above, according to the present invention, by providing a shielding member between a window and a graphite target, nanocarbon can be produced in high yield. Further, according to the present invention, the life of the nanocarbon production apparatus can be extended.

BRIEF DESCRIPTION OF THE FIGURES

[0033] The above objects and other objects, features, and advantages will become more apparent from the preferred embodiments described below and the accompanying drawings described below.

FIG. 1 is a diagram showing a configuration of a nanocarbon producing apparatus according to an embodiment.

FIG. 2 is a diagram showing a configuration of a nanocarbon production apparatus according to an embodiment.

FIG. 3 is a diagram showing a configuration of a nanocarbon producing apparatus according to an embodiment.

FIG. 4 is a diagram showing a configuration of a nanocarbon producing apparatus according to an embodiment.

FIG. 5 is a diagram showing a configuration of a nanocarbon production apparatus according to an embodiment.

FIG. 6 is a diagram showing a configuration of a nanocarbon producing apparatus according to an embodiment. FIG. 7 is a diagram showing a configuration of a nanocarbon producing apparatus according to an embodiment.

FIG. 8 is a diagram showing a configuration of a nanocarbon production apparatus according to an example.

FIG. 9 is a view showing a configuration of a nanocarbon producing apparatus according to an example.

FIG. 10 is a view showing a configuration of a nanocarbon production apparatus according to an example.

FIG. 11 is a diagram showing the time of breakage of a ZnSe window in each device of the example.

FIG. 12 is a view showing the relationship between the production time and the yield of carbon nanohorn aggregates in Examples.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(First Embodiment)

The present embodiment relates to a nanocarbon manufacturing apparatus in which the periphery of the optical path of light irradiated on the surface of a graphite target is covered with a cover. FIG. 1 is a cross-sectional view illustrating an example of the configuration of a nanocarbon manufacturing apparatus according to the present embodiment. In this specification, FIG. 1 and the drawings used for describing other manufacturing apparatuses are schematic views, and the sizes of the respective components do not always correspond to actual dimensional ratios.

[0037] The nanocarbon production apparatus 125 of Fig. 1 includes a production chamber 107, a nanocarbon recovery chamber 119, and a transfer pipe 141 connecting these. In addition, the manufacturing apparatus shown in FIG. 1 is a rotating device that holds a laser light source 111 that emits a laser beam 103, a ZnSe plano-convex lens 131, a ZnSe window 133, a cover 167, and a graphite rod 101, and rotates around its central axis. 115 is provided. Further, the nanocarbon production apparatus 125 includes an inert gas supply section 127, a flow meter 129, a vacuum pump 143, and a pressure gauge 145.

In the nanocarbon production apparatus 125, the light emitted from the laser light source 111 is condensed by a ZnSe plano-convex lens 131, and passes through a ZnSe window 133 provided on the wall surface of the production chamber 107 so that the light in the production chamber Irradiated on graphite rod 101. At this time, the laser beam ₁₀₃ passes through a cover 167 provided along the optical path.

The graphite rod 101 is used as a solid carbon substance as a target for irradiation with the laser beam 103. The graphite rod 101 is fixed to a rotating device 115, and is rotatable around a central axis. For example, a laser beam 1 The position of the part irradiated with 03 can rotate the graphite rod 101 so as to move away from the irradiation direction of the laser beam 103. Specifically, in FIG. 1, the graphite rod 101 can be rotated clockwise with respect to the central axis. This makes it possible to more reliably suppress the generation of return light.

[0040] Then, the carbon nanohorn aggregate 117 can be reliably recovered while stably providing a new irradiation surface to be irradiated with the laser beam 103. By fixing the graphite rod 101 to the rotating device 115, it is possible to rotate the rod around the central axis. Further, the graphite rod 101 can be configured to be movable in a direction along the central axis, for example.

[0041] The transfer pipe 141 communicates with and connects the production chamber 107 and the nanocarbon recovery chamber 119. The side of the graphite rod 101 is irradiated with laser light 103 from a laser light source 111, and a nanocarbon recovery chamber 119 is provided via a transfer pipe 141 in the direction in which the plume 109 is generated. The carbon nanohorn aggregate 117 is collected in the nanocarbon collection chamber 119.

[0042] The plume 109 is generated in a direction perpendicular to the tangent line of the graphite rod 101 at the irradiation position of the laser beam 103, that is, in the normal direction. Therefore, if the transport pipe 141 is provided in this direction, the carbon vapor is efficiently generated. The powder is guided to the nanocarbon recovery chamber 119, and the powder of the carbon nanohorn aggregate 117 can be recovered. For example, when the irradiation angle is 45 °, the transfer pipe 141 can be provided in a direction that forms 45 ° with respect to the vertical.

In the nanocarbon production apparatus 125, a cylindrical cover 167 covering the optical path is provided in the production chamber 107 along the passage of the laser beam 103 from near the ZnSe window 133 to near the surface of the graphite rod 101. Is provided. The cover 167 is provided up to the vicinity of the graphite rod 101, and has an open end. The laser beam 103 passes through the force bar 167 and is irradiated on the surface of the graphite rod 101. .

By providing the cover 167, a light irradiation path to the graphite rod 101 is secured, and a soot-like substance obtained from carbon vapor generated by irradiating the surface of the graphite rod 101 with the laser beam 103 is provided. The ZnSe window 133 can be shielded so as not to adhere. Since the adhesion of soot-like substances to the surface of the ZnSe window 133 is suppressed, the ZnSe window Absorption of the laser beam 103 on the surface of the dough 133 is suppressed. Therefore, it is possible to suppress the fluctuation of the power density of the laser beam 103 applied to the surface of the graphite rod 101. Further, an excessive rise in temperature of the ZnSe window 133 can be suppressed. Accordingly, it is possible to suppress the displacement of the irradiation position of the laser beam 103 on the surface of the graphite rod 101 due to the thermal lens effect. Further, it is possible to suppress the deterioration of the ZnSe window 133 due to overheating, and the accompanying damage or combustion.

[0045] Therefore, the nanocarbon production apparatus 125 can stably produce the carbon nanohorn aggregate 117 in a high yield. Also, it is possible to easily realize a device configuration with excellent durability.

The nanocarbon production apparatus 125 is provided with a transfer pipe 141 so as to cover the plume 109 along the direction in which the plume 109 is generated. The transfer pipe 141 communicates with a nanocarbon recovery chamber 119 provided on the side of the production chamber 107. When the laser light 103 is irradiated on the surface of the graphite mouth 101, a plume 109 is generated, and the plume 109 is released, so that the carbon vapor becomes a soot-like substance. In the nanocarbon production apparatus 125, since the transfer pipe 141 is formed in the direction in which the plume 109 is generated, the transfer pipe 141 is reliably guided to the nanocarbon recovery chamber 119 through the transfer pipe 141. For this reason, the collection efficiency of the carbon nanohorn aggregate 117 can be improved. The plume 109 is generated in a direction perpendicular to a tangent to the irradiation position of the laser beam 103 on the surface of the graphite rod 101.

[0047] Further, the nanocarbon production apparatus 125 is configured to irradiate the side face thereof with the laser beam 103 while rotating the graphite rod 101 in the circumferential direction. Irradiation of the laser beam 103 is performed in a positional relationship in which the direction of the laser beam 103 does not coincide with the direction in which the plume 109 is generated. In this way, the carbon nanohorn aggregate 117 can be efficiently collected at a position where the irradiation path of the laser beam 103 is not interrupted.

[0048] In the nanocarbon production apparatus 125, the angle of the punolem 109 generated on the side surface of the graphite rod 101 can be predicted in advance. Therefore, the position and the angle of the transfer pipe 141 can be precisely controlled. Therefore, the carbon nanohorn assembly 117 can be efficiently produced under the conditions described later, and can be reliably recovered. Next, a method for manufacturing the carbon nanohorn aggregate 117 using the nanocarbon manufacturing apparatus 125 of FIG. 1 will be specifically described.

[0050] In the nanocarbon production apparatus 125, as the graphite rod 101, high-purity graphite, for example, round rod-shaped sintered carbon, compression molded carbon, or the like can be used.

As the laser beam 103, for example, a high-power C〇 gas laser can be used. Irradiation of the graphite rod 101 of the laser beam 103, Ar, performs a rare gas such as He reaction inert gas atmosphere to This First, for example 10 ³ Pa or more 10 ⁵ Pa in the following atmosphere. Further, after the evacuated beforehand example below 10- ² Pa within the production chamber one 107, Shi preferred that the inert gas atmosphere Rere.

The output, spot diameter, and irradiation angle of the laser beam 103 are set so that the power density of the laser beam 103 on the side surface of the graph rod 101 is substantially constant, for example, 5 kW / cm ² or more and 25 kW / cm ² or less. It is preferable to adjust the.

[0053] The output of the laser beam 103 is, for example, lkW or more and 50kW or less. The pulse width of the laser beam 103 is, for example, 0.5 seconds or more, and preferably 0.75 seconds or more. By doing so, the accumulated energy of the laser beam 103 applied to the surface of the graphite rod 101 can be sufficiently secured. Therefore, it is possible to efficiently manufacture the carbon nanohorn aggregate 117. Further, the pulse width of the laser beam 103 is, for example, 1.5 seconds or less, and preferably 1.25 seconds or less. By doing so, it is possible to prevent the surface of the graphite rod 101 from being excessively heated, thereby fluctuating the energy density of the surface and reducing the yield of the carbon nanohorn aggregate. More preferably, the pulse width of the laser beam 103 is 0.75 seconds or more and 1 second or less. This can improve both the production rate and the yield of the carbon nanohorn aggregate 117.

[0054] Further, the rest width in the irradiation of the laser beam 103 can be, for example, 0.1 seconds or more, and preferably 0.25 seconds or more. By doing so, overheating of the surface of the graphite rod 101 can be more reliably suppressed.

[0055] The laser beam 103 is applied so that the irradiation angle is constant. By rotating the graphite rod 101 at a predetermined speed with respect to the center axis thereof while keeping the irradiation angle of the laser beam 103 constant, the laser beam 103 is directed in a circumferential direction on the side surface of the graphite rod 101. Irradiation can be performed continuously at a constant power density. Further, by sliding the graphite rod 101 in its length direction, the laser beam 103 can be continuously irradiated at a constant power density in the length direction of the graphite rod 101.

The irradiation angle at this time is preferably 30 ° or more and 60 ° or less. The irradiation angle is an angle between a perpendicular to the surface of the graphite target at the irradiation position of the laser beam 103 and the laser beam 103. When using the graphite rod 101 which is a cylindrical graphite rod target, in a section perpendicular to the length direction of the graphite rod 101, a line segment connecting the irradiation position and the center of the circle and an angle formed by a horizontal plane Define.

By setting the irradiation angle to 30 ° or more, it is possible to prevent reflection of the irradiation laser beam 103, that is, generation of return light. In addition, the generated phenolic 109 is prevented from directly hitting the ZnSe plano-convex lens 131 through the ZnSe window 133. Therefore, it is effective to protect the ZnSe plano-convex lens 131 and to prevent the carbon nanohorn aggregate 117 from adhering to the ZnSe window 133. Therefore, the power density of the laser beam 103 irradiated on the graphite rod 101 can be stabilized, and the carbon nanohorn aggregate 117 can be stably manufactured with a high yield.

Further, by irradiating the laser beam 103 at a temperature of 60 ° or less, the generation of amorphous carbon is suppressed, and the ratio of the carbon nanohorn aggregates 117 in the product, that is, the yield of the carbon nanohorn aggregates 117 is improved. Can be done. It is particularly preferable that the irradiation angle is 45 ° ± 5 °. By irradiating at about 45 °, the ratio of the carbon nanohorn aggregates 117 in the product can be further improved.

The nanocarbon production apparatus 125 has a configuration in which the side surface of the graphite rod 101 is irradiated with laser light 103. For this reason, by adjusting the height of the graphite rod 101 with the position of the ZnSe plano-convex lens 131 fixed, it is possible to change the irradiation angle S on the side surface. By changing the irradiation angle of the laser beam 103, the irradiation area of the laser beam 103 on the surface of the graphite rod 101 can be changed, the power density can be made variable, and the power S can be adjusted reliably.

More specifically, for example, when the position of the ZnSe plano-convex lens 131 is fixed, the power density can be increased by setting the irradiation angle to 30 °. Also, for example, the irradiation angle By setting the angle to 60 °, the power density can be controlled to be low.

[0061] The spot diameter of the laser beam 103 on the side of the graphite rod 101 during irradiation can be, for example, 0.5 mm or more and 5 mm or less.

Further, it is preferable to move the spot of the laser beam 103 at a linear velocity (peripheral velocity) of, for example, not less than 0.1 OlmmZsec and not more than 55 mm / sec. If the linear velocity is high, the length of irradiation of the laser beam 103 on the surface of the graphite rod 101 in one pulse irradiation is long, whereas the evaporation of carbon from the surface of the graphite rod 101 occurs only at the depth from the surface. Is limited to small areas. On the other hand, if the linear velocity is low, the length of irradiation of the laser beam 103 on the surface of the graphite rod 101 in one pulse irradiation is short, but the region where the depth from the surface of the graphite rod 101 is large is large. Evaporation occurs.

[0063] The amount of soot-like substance generated per unit time, that is, the rate of soot-like substance generation and the yield of carbon nanohorn aggregates 117 in the generated soot-like substance are determined by the moving distance of the irradiation position in one pulse light irradiation. It is presumed that it depends on the depth of carbon and carbon evaporation. If the depth at which the carbon evaporates is too deep, a substance other than the carbon nanohorn aggregate 117 is generated, and the yield decreases. Also, if the depth is too shallow, the carbon nanohorn aggregates 117 will not be sufficiently generated. By setting the linear velocity under the above conditions, the carbon nanohorn aggregate 117 can be efficiently produced with a high yield.

For example, when irradiating a laser beam 103 onto the surface of a graphite target having a diameter of 100 mm, the rotating rod 115 rotates the graphite rod 101 having a diameter of 100 mm in the circumferential direction at a constant speed, and the number of rotations is reduced. For example, the linear velocity described above can be realized when the rotational speed is set to be equal to or more than 0.1 Olrpm and equal to or less than 10 Orpm. There is no particular limitation on the rotation direction of the graphite rod 101. The force irradiation position is a force away from the laser beam 103), that is, as shown by the arrow in FIG. It is preferable to rotate in the direction of the force. This makes it possible to more reliably recover the carbon nanohorn aggregate 117.

The soot-like substance recovered in the nanocarbon recovery chamber 119 mainly includes the carbon nanohorn aggregate 117, and is collected, for example, as a substance containing 90 wt% or more of the carbon nanohorn aggregate 117. In the production of nanocarbon using the nanocarbon production apparatus 125, the transfer pipe 141 extends along the emission direction of the laser beam 103 from the ZnSe window 133 to the surface of the graphite rod 101, or from the surface of the graphite rod 101. Via the nanocarbon recovery chamber, one may form an airflow along the direction to 119. For example, an air intake section may be further provided to generate an airflow along the traveling direction of the laser beam 103 from the side of the laser light source 111 to the side of the graphite rod 101. In this way, the force S can be more reliably suppressed from adhering the soot-like substance from the surface of the graphite rod 101 in the direction of the ZnSe window 133. Further, since the generated carbon nanohorn aggregate 117 can be more reliably guided from the transfer pipe 141 to the nanocarbon recovery chamber 119, the recovery rate of the carbon nanohorn aggregate 117 can be improved.

In the nanocarbon manufacturing apparatus 125, a ZnSe plano-convex lens may be provided as a ZnSe plano-convex lens 131 and a ZnSe window 133 using a ZnSe window 133. In other words, in this case, the ZnSe plano-convex lens 131 is not provided outside the manufacturing chamber 107, and a lens is used as a window for sealing the manufacturing chamber 107. In this way, a simple and highly efficient device configuration can be realized.

In the apparatus shown in FIG. 1 and the apparatus described in the following embodiments, the laser light source 111 is provided above the manufacturing chamber 107. Then, the carbon nanohorn aggregate 117 generated by the irradiation of the laser beam 103 is collected in the nanocarbon collection chamber 119 provided on the side of the production chamber 107 via the transfer pipe 141. In this embodiment and the following embodiments, the arrangement of the laser light source 111 is not necessarily limited to a mode in which the laser light source 111 is provided above the manufacturing chamber 107.

For example, FIG. 2 is a diagram showing another configuration of the nanocarbon producing apparatus having the cover 167. In the apparatus shown in FIG. 2, a laser light source 111 is provided on a side of the manufacturing chamber 107, and a laser beam 103 is emitted from a side surface of the manufacturing chamber 107 toward the graphite rod 101. At this time, the plume 109 is generated in a direction perpendicular to the tangent to the irradiation position of the graphite rod 101. In the positional relationship shown in FIG. 2, the punolem 109 is generated in the manufacturing chamber 107 in a direction at an angle of 45 ° with respect to the vertical direction. In the apparatus of FIG. 2, as in the apparatus of FIG. A transport pipe 141 is provided in parallel with the generation direction, so that the soot-like substance generated from the punolem 109 is recovered in a nanocarbon recovery chamber 119 provided above the production chamber 107.

In the apparatus shown in FIG. 2, the rotating device 115 has a rotating mechanism that holds the graphite rod 101 and rotates it along the central axis thereof. Also, in the case of the apparatus shown in FIG. 2, similarly to the apparatus shown in FIG. 1, the graphite rod 101 is configured to be movable in the direction of the central axis.

Further, in the apparatus shown in FIG. 1, a cover 167 is provided as a shielding member for protecting the ZnSe window 133 along the optical path of the laser beam 103 emitted from the laser light source 111 along the optical path. The mode of the shielding member is not limited to this.

For example, FIG. 3 shows an apparatus having a configuration in which a partition 179 is provided instead of the cover 167 of the nanocarbon production apparatus 125 shown in FIG. Other configurations are the same as those of the nanocarbon production apparatus 125. In the apparatus shown in FIG. 3, a partition 179 is provided in the manufacturing chamber 107. The partition wall 179 divides the production chamber 107 into two chambers, a chamber in which the ZnSe window 133 is provided and a chamber in which the graphite rod 101 is provided. The partition wall 179 is provided with a hole for allowing the laser beam 103 to pass therethrough to reach the graphite rod 101. Therefore, it is possible to irradiate the graphite rod 101 with laser light. By providing the partition 179, the soot-like substance generated from the graphite rod 101 side can be blocked from moving to the ZnSe window 133 side. Therefore, the soot-like substance can be suppressed from adhering to the surface of the ZnSe window 133.

Further, in the apparatus shown in FIGS. 1 to 3, the power window in which the ZnSe window 133 was provided on the wall surface of the manufacturing chamber 107 as a window is a mode in which a part of the power window is exposed in the manufacturing chamber 107. If it is, it is not limited to this configuration. For example, a laser light source 111 having a window on the emission end face may be arranged in the manufacturing chamber 107. In this case, the soot-like substance is prevented from adhering to the window of the laser light source 111 by shielding the space between the laser light source 111 and the graphite rod 101 with a shielding member such as the cover 167 or the partition wall 179. . Further, the ZnSe plano-convex lens 131 may be provided in the manufacturing chamber 107. In this case, for example, the cover between the ZnSe plano-convex lens 131 and the graphite rod 101 is By shielding with the 167 or the partition 179, the adhesion of the soot-like substance to the surface of the ZnSe plano-convex lens 131 can be suppressed.

(Second Embodiment)

The present embodiment relates to a nanocarbon manufacturing apparatus having a configuration in which light emitted from a light source 111 is not directly applied to the surface of the graphite rod 101, but is reflected and changed the optical path, and then applied to the surface of the graphite rod 101. .

FIG. 4 is a cross-sectional view showing a state where the nanocarbon producing apparatus 173 according to the present embodiment is viewed from the side. In the present embodiment, the same components as those of the nanocarbon manufacturing apparatus 125 described in the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

In the nanocarbon production apparatus 125 (FIG. 1), the laser beam 103 emitted from the laser light source 111 is condensed by the ZnSe plano-convex lens 131 so that the spot diameter on the surface of the graphite rod 101 becomes a predetermined size. In contrast to the configuration in which the ZnSe window 133 irradiates the inside of the production chamber 107, the nanocarbon production apparatus 173 shown in FIG. From 133, it is irradiated into the production chamber 107. Since the nanocarbon production apparatus 173 has a plane mirror 169 and a parabolic mirror 171 for changing the optical path of the laser beam 103, the laser beam 103 is reflected by the plane mirror 169 in the production chamber 107, and The light is reflected by the plane mirror 171. The light reflected by the parabolic mirror 171 is collected on the surface of the graphite rod 101 installed near the focal point of the parabolic mirror 171.

As described above, in the nanocarbon production apparatus 173, the laser beam 103 that has entered the production chamber 107 through the ZnSe window 133 does not directly irradiate the surface of the graphite rod 101. After being reflected twice by the parabolic mirror 171 and changing the optical path, the light is irradiated onto the surface of the graphite rod 101. Further, since the light passes through the plane mirror 169 and the parabolic mirror 171, the optical path length from the ZnSe window 133 to the graphite rod 101 is increased in the nanocarbon manufacturing apparatus 173 as compared with the nanocarbon manufacturing apparatus 125. be able to.

[0078] Thus, device configurations and the attachment to the plume 109 and _ZnSe window _{1 33} of the soot-like material from the plume 1 0 ₉ surface forces generated in graphite rod 101 is suppressed Has become. Therefore, even if the nanocarbon production apparatus 173 is used for a long time, it is possible to suppress a change in the power density of the laser beam 103 applied to the surface of the graphite rod 101. For this reason, a decrease in the yield of the carbon nanohorn aggregate 117 can be suppressed, and the carbon nanohorn aggregate 117 can be stably continuously produced. Further, the device life of the nanocarbon production device 173 can be extended.

[0079] In the nanocarbon producing apparatus 173, for example, Cu can be used as the material of the plane mirror 169 or the parabolic mirror 171. Since Cu has a high thermal conductivity, heat is efficiently radiated even if soot-like substances adhere to the surface. The plane mirror 169 and the parabolic mirror 171 may have a surface coated with, for example, Au or Mo. By using such a material, breakage of the plane mirror 169 or the parabolic mirror 171 can be suppressed.

In the nanocarbon producing apparatus 173, the light emitted from the laser light source 111 is reflected twice, and then is emitted to the surface of the graphite rod 101. There is no particular limitation on the number of reflections as long as the configuration reaches the surface of the graphite rod 101 after changing the optical path. It can be configured to reflect once, or it can be reflected three or more times to reflect the graphite rod 101. Irradiation may be performed.

Further, in the nanocarbon producing apparatus 173, the laser beam 103 is reflected by the parabolic mirror 171 so as to be condensed on the surface of the graphite rod 101. The shape of the reflecting mirror is not limited to the parabolic mirror 171 as long as it can collect light. For example, a concave mirror having another shape can be used. Further, a plurality of reflecting mirrors may be combined to collect light on the surface of the graphite rod 101.

(Third Embodiment)

The present embodiment relates to another configuration of the nanocarbon production device. Also in this embodiment, the same components as those of the nanocarbon production apparatus 125 (FIG. 1) or the nanocarbon production apparatus 173 (FIG. 4) described in the first or second embodiment are denoted by the same reference numerals. The description is omitted as appropriate.

FIG. 5 is a cross-sectional view showing a state where the nanocarbon producing apparatus 175 according to the present embodiment is viewed from the side. The basic configuration of the nanocarbon production system 175 is the same as that of the nanocarbon production system 173 (Fig. 4). The difference from the nanocarbon production apparatus 173 is that a cover 167 for protecting the passage route is provided.

By providing the cover 167, the soot-like substance generated from the plume 109 can be further reliably prevented from directly adhering to the ZnSe window 133 as described in the first embodiment. Further, soot-like substances can be more reliably prevented from adhering to the surface of the plane mirror 169 or the parabolic mirror 171. For this reason, deviation of the irradiation position or power density of the laser beam 103 on the surface of the graphite rod 101 is suppressed, and a decrease in the yield of the carbon nanohorn aggregate 117 is suppressed. In addition, the life of the device can be further extended.

[0085] In the nanocarbon production apparatus 175 of Fig. 5, the cover 167 is provided in contact with the wall surface of the production chamber 107, so that the ZnSe window 133 is provided inside the production chamber 107. However, as long as the inert gas can be sealed in the manufacturing chamber 107, the position of the ZnSe window 133 is not limited to the inside of the manufacturing chamber 107. For example, the ZnSe window 133 may be provided on the wall surface of the manufacturing chamber 107. For example, FIG. 6 is a diagram showing a nanocarbon manufacturing apparatus 176 in which a ZnSe window 133 is provided on a wall surface of a manufacturing chamber 107.

(Fourth Embodiment)

In the above embodiments, the case where the graphite rod is used has been described as an example. However, in each of these embodiments, the shape of the graphite target is not limited to a cylindrical shape, and may be, for example, a sheet shape, a rod shape, or the like. And so on.

[0087] For example, FIG. 7 is a diagram showing an apparatus configuration in the case of using a sheet-like graphite target in the nanocarbon production apparatus 175 (FIG. 5) according to the third embodiment.

In the nanocarbon production apparatus 177 shown in FIG. 7, the graphite target 139 is a solid carbon simple substance serving as a target for irradiation with the laser beam 103. The graphite target 139 is held by a target holding section 153 on a target supply plate 135. The plate holding unit 137 translates the target supply plate 135 in the horizontal direction. For this reason, when the target supply plate 135 moves, the graphite target 139 installed thereon moves by a force S, and the position between the irradiation position of the laser beam 103 and the surface of the graphite target 139 moves. The relative position moves.

For example, screw ridges (not shown) are formed on the bottom surface of the target supply plate 135 and the surface of the plate holding portion 137, and the target supply plate 135 is moved from the upper left to the lower right in FIG. It can be configured to be mobile. Also, a groove (not shown) or the like is formed on the surface of the target supply plate 135, and a protrusion (not shown) is formed at the bottom of the target holding portion 153 so that the groove can slide. The target holding unit 153 and the graph object target 139 held by the target holding unit 153 can be configured to be movable in a direction perpendicular to the plane of FIG.

With such a configuration, the graphite target 139 can be supplied to the irradiation position of the laser light 103 emitted from the laser light source 111.

[0091] Further, when the graphite target is formed in a sheet shape or a rod shape, the thickness is set to a size that can be completely used when the laser beam 103 is irradiated once or several times and all evaporated. Thereby, the yield of the carbon nanohorn aggregate 117 can be further improved. This is because the surface of the graphite rod 101 is roughened when irradiated with the laser beam 103, and the power density is deviated when the laser beam 103 is irradiated again. This is because the smaller the number of times the surface is irradiated with the laser beam 103, the more stable the force-bonded nanohorn assembly 117 can be produced.

[0092] The present invention has been described based on the embodiments. It is understood by those skilled in the art that these embodiments are exemplifications and various modifications are possible, and that such modifications are also within the scope of the present invention.

[0093] In the apparatus according to the above embodiment, the soot-like substance obtained by the irradiation of the laser beam 103 is deposited on the substrate having an appropriate structure configured to be recovered in the nanocarbon recovery chamber 119. And can be collected by a method of collecting fine particles using a dust bag. In addition, an inert gas can be circulated in the reaction vessel to recover soot-like substances by the flow of the inert gas.

In the above embodiment, when manufacturing the carbon nanohorn aggregate 117, conditions such as the power density of irradiation light on the surface of the graphite target, the pulse width, the pause width, or the moving speed of the graphite target are as shown in the graph. Ait target shape and desired force It can be appropriately selected according to the shape of the one-bon nanohorn assembly 117. In addition, the shape, diameter, length, shape of the tip, the spacing between carbon molecules and carbon nanohorns, etc. of the carbon nanohorns constituting the carbon nanohorn assembly 117 vary depending on the irradiation conditions of the laser beam 103 and the like. It is possible to control.

In the apparatus shown in the second to fourth embodiments (FIGS. 4 to 7), a force window in which a ZnSe window 133 is provided on the wall surface of the manufacturing chamber 107 is used as a window. The configuration is not limited to this configuration as long as a part is exposed in 107. For example, a laser light source 111 having a window on the emission end face may be arranged in the manufacturing chamber 107. In this case, the light emitted from the laser light source 111 is reflected by a reflecting mirror such as a plane mirror 169 or a parabolic mirror 171 and then reaches the surface of the graphite rod 101, so that the light is emitted to the window of the laser light source 111. Adhesion of soot-like substances is suppressed. Further, a ZnSe plano-convex lens 131 may be provided in the manufacturing chamber 107. In this case, the light transmitted through the ZnSe plano-convex lens 131 is reflected by a reflecting mirror such as a plane mirror 169 or a parabolic mirror 171 and then reaches the surface of the graphite rod 101 so that the ZnSe plano-convex lens 131 Adhesion of soot-like substances to the surface can be suppressed.

[0096] Further, in the apparatus shown in the second to fourth embodiments (Figs. 4 to 7), a cooling mechanism for cooling parabolic mirror 171 may be further provided. By cooling the parabolic mirror 171, excessive heating is suppressed even when a soot-like substance adheres to the surface of the parabolic mirror 171, so that the life of the apparatus can be further extended. Further, a dust cleaning mechanism for removing soot-like substances attached to the surface of parabolic mirror 171 may be provided. With such a configuration, even if soot-like substance adheres to the surface of the parabolic mirror 171, it can be removed at an appropriate timing, so that the light irradiated on the surface of the graphite rod 101 can be removed. It is possible to more reliably control the power density so as to be a constant value. For this reason, the yield of carbon nanohorn aggregate can be further improved. In addition, the life of the device can be further extended. Here, the cooling mechanism and the dust cleaning mechanism have been described by taking the case of the parabolic mirror 171 as an example. However, it is possible to provide these mechanisms to the plane mirror 169 as needed. [0097] Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited thereto.

[0098] (Example)

In this example, the carbon nanohorn aggregate 117 was manufactured by the laser ablation method using the nanocarbon manufacturing apparatus 126 shown in FIG. 2 and the nanocarbon manufacturing apparatus shown in FIGS. 8, 9, and 10. Was. However, FIGS. 8 and 9 show the laser beam 103 from the side of the production chamber 107 in the nano-force production apparatus 173 of FIG. 4 and the nanocarbon production apparatus 175 of FIG. 5, respectively, similarly to the nanocarbon production apparatus 126. This device is configured to be incident. Further, the apparatus of FIG. 10 has the same configuration as the nanocarbon production apparatus 126 of FIG. 2 and is different from the nanocarbon production apparatus 126 in that it does not have the cover 167.

[0099] The sintered rod carbon 100mm in diameter as the solid carbon material was placed in a vacuum vessel, after evacuating the inside of the container to a 10- ² Pa, an Ar gas 1. 01325 X 10 ⁵ Pa Atmosphere Pressure. Next, the solid carbon material was irradiated with a high-power CO laser beam at room temperature. The laser output was 100 W and the power density on the surface of the solid carbon material was 22 kW / cm ² . The pulse width was set to 1 sec, the rest width was set to 250 msec, and the solid carbon material was irradiated with laser light while rotating at 6 rpm so that the irradiation angle was 45 °. Laser single light irradiation was performed until the ZnSe window was broken, and the time until the ZnSe window was broken in each device was measured.

[0100] Furthermore, in the case of using the apparatus of Fig. 10 and the nanocarbon production apparatus 173 of Fig. 8, the relationship between the production time and the yield of the carbon nanohorn aggregate 117 was examined.

FIG. 11 is a diagram showing the damage time of the ZnSe window in each device. In FIG. 11, “ZnSe” is an experimental result for the apparatus of FIG. In addition, “ZnSe + nanocarbon adhesion prevention cone”, “parabolic mirror”, and “parabolic mirror + nanocarbon adhesion prevention cone” are the nanocarbons shown in Figs. 2, 8, and 9, respectively. These are the results of experiments on manufacturing equipment.

[0102] From FIG. 11, it has been clarified that the durability of the ZnSe window 133 is increased by providing the cover 167 in the device configuration for condensing light using the ZnSe plano-convex lens 131. Ma In addition, it is clear that the converging configuration using the parabolic mirror 171 significantly increases the lifetime of the ZnSe window 133, and further increases by providing the cover 167. Was.

[0103] From these results, it was confirmed that the apparatus life can be prolonged by employing a configuration in which the laser beam 103 is reflected and condensed using the parabolic mirror 171 and then irradiated onto the surface of the Daraphyte rod 101. Was done.

FIG. 12 shows the relationship between the production time and the yield of the carbon nanohorn aggregate 117 for the “ZnSe” and “parabolic mirror” devices in FIG. 11, ie, the devices in FIGS. 10 and 8. FIG. 12, the yield of the carbon nanohorn aggregate 117 decreases in the apparatus of FIG. 10 as the production time elapses. On the other hand, when the nanocarbon production apparatus 173 of FIG. 8 is used, even if the production time is prolonged, the yield of the carbon nanohorn aggregate 117 does not decrease, and the yield is almost constant. Therefore, the laser beam 103 is reflected by the plane mirror 169 and the parabolic mirror 171, and the laser beam 103 is condensed on the surface of the graphite rod 101 by the parabolic mirror 171, so that the carbon nanohorn aggregate is stably formed. It was found that the compound can be produced in a high yield.

Claims

The scope of the claims

[1] Graphite targets,

A chamber containing the graphite target,

A window provided in a part of the chamber;

A light source that irradiates light to the surface of the graphite target through the window; and a recovery unit that recovers nanocarbon generated from carbon vapor evaporated from the graphite target by irradiation of the light.

A shielding member interposed between the window portion and the graphite target,

An apparatus for producing nanocarbon, comprising:

[2] The apparatus for producing nanocarbon according to claim 1,

An apparatus for producing nanocarbon, comprising: an optical member for guiding the light to the surface of the graphite target between the window and the shielding member.

3. The apparatus for producing nanocarbon according to claim 1, wherein the optical member includes a reflection member.

[4] Graphite targets,

A chamber containing the graphite target,

A window provided in a part of the chamber;

A reflecting member for reflecting transmitted light transmitted through the window and guiding the light to the surface of the graphite target;

An apparatus for producing nanocarbon, comprising:

[5] The apparatus for producing nanocarbon according to claim 4, further comprising a shielding member interposed between the reflection member and the graphite target. .

[6] The apparatus for producing nanocarbon according to any one of claims 3 to 5, wherein the reflecting member has a light-collecting action.

[7] The apparatus for producing nanocarbon according to any one of claims 3 to 6, wherein the reflecting member is a parabolic mirror.

[8] The apparatus for producing nanocarbon according to any one of claims 1 to 7, wherein the target holding the cylindrical graphite target and rotating the graphite target about a central axis. An apparatus for producing nanocarbon, characterized by comprising means.

[9] The apparatus for producing nanocarbon according to any one of claims 1 to 8, wherein the nanocarbon is a carbon nanohorn aggregate.