JPWO2004113225A1 - Nanocarbon production equipment - Google Patents

Abstract

In the nanocarbon production apparatus (173), a plane mirror (169) and a parabolic mirror (171) are provided in the production chamber (107). The light emitted from the laser light source (111) that has passed through the ZnSe window (133) is reflected by the plane mirror (169) and the parabolic mirror (171), and further condensed by the parabolic mirror (171). Irradiate the surface of the rod (101).

Description

  The present invention relates to an apparatus for producing nanocarbon.

  In recent years, the engineering application of nanocarbon has been actively studied. Nanocarbon refers to a carbon substance having a nanoscale microstructure represented by carbon nanotubes, carbon nanohorns, and the like. Among these, the carbon nanohorn has a tubular structure in which one end of a carbon nanotube in which a graphite sheet is rounded into a cylindrical shape has a conical shape. Carbon nanohorns usually gather together in a form in which the conical portions protrude from the surface like horns (horns) around the tube by van der Waals forces acting between the conical portions to form a carbon nanohorn aggregate. Carbon nanohorn aggregates are expected to be applied to various technical fields because of their unique properties.

It has been reported that a carbon nanohorn aggregate is produced by a laser evaporation method in which a raw material carbon substance (hereinafter also referred to as “graphite target”) is irradiated with laser light in an inert gas atmosphere (Patent Literature). 1). Patent Document 1 exemplifies a CO ₂ gas laser as the laser light.

By the way, the wavelength of the CO ₂ gas laser is about 10.6 μm, and ZnSe or the like is suitably used as a material that transmits the CO ₂ gas laser (Patent Document 2). For this reason, when manufacturing a carbon nanohorn aggregate using a CO ₂ gas laser, it is considered that laser light can be condensed on the surface of the graphite target by using a ZnSe lens.

JP 2001-64004 A JP 2001-51191 A

  Therefore, the present invention examined a method for producing a carbon nanohorn aggregate by providing a ZnSe window (hereinafter also referred to as “laser beam window”) in a production chamber. As a result, it was found that the weight ratio (hereinafter referred to as “yield”) of the carbon nanohorn aggregates in the collected soot-like material decreases as the use time of the laser beam window becomes longer. In addition, the life of the laser beam window is relatively short and may be damaged in some cases. As a result, it has been found that the maintenance of the apparatus is expensive and the life of the apparatus itself is shortened. Also, the life of the ZnSe lens provided outside the chamber was relatively short.

  Therefore, the cause of the decrease in the yield of the carbon nanohorn aggregate and the cause of the short life of the laser light window or the lens were investigated. As a result, it was found that when a graphite target is irradiated with laser light, soot-like substances generated from carbon vapor generated from the graphite target may adhere to the surface of the laser light window. It was. It has also been clarified that when soot-like substances adhere to the surface of the laser light window or the lens, the laser light window or the lens is heated by absorbing light at the adhered portion.

In such a case, the optical path may be shifted due to the thermal lens effect. The deviation of the optical path can cause the position where the surface of the graphite target is irradiated with the CO ₂ gas laser, or the power density of the light applied to the surface can be a factor of change. It was speculated that this was the cause of the yield reduction accompanying the increase in the usage time of the apparatus. In addition, it was speculated that heating of the laser beam window and the lens would cause damage. For this reason, the technique of manufacturing, without reducing the yield of a carbon nanohorn aggregate | assembly was required. Further, in order to extend the life of the apparatus, a technique different from the conventional technique is required.

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

  The present inventors diligently studied a method for obtaining nanocarbon with high efficiency. As a result, when the light emitted from the light source is irradiated onto the surface of the graphite target using the optical member, it has been found that it is important to shield the optical member from adhesion of soot-like substances, and the present invention has been achieved. Also, the light emitted from the light source is not directly irradiated onto the surface of the graphite target, but is reflected to change the optical path, and then irradiated onto the graphite target, so that the optical member is protected from adhesion of soot-like substances. The invention has been reached.

  According to the present invention, a graphite target, a chamber containing the graphite target, a window provided in a part of the chamber, and a light source for irradiating light on the surface of the graphite target through the window And a recovery part for recovering nanocarbon generated from carbon vapor evaporated from the graphite target by the light irradiation, and a shielding member interposed between the window part and the graphite target. An apparatus for producing nanocarbon is provided.

  In the present invention, a shielding member is provided between the window portion and the graphite target. As described above, when the light emitted from the light source is configured to be directly irradiated onto the surface of the graphite target after passing through the window, the soot-like substance obtained from the carbon vapor generated from the surface of the graphite target is The soot-like substance easily adheres to the surface of the window because it also scatters in the direction returning to the side. For this reason, when the optical member made from ZnSe was used, the optical member was easy to be heated.

  On the other hand, in the configuration of the present invention, the window is shielded from the surface of the graphite target. With this configuration, even when soot-like substances generated from the surface of the graphite target are scattered to the window side, the soot-like substance moves toward the window part because it is shielded by the shielding member, and the surface Adhering to is suppressed. For this reason, the power density of the light irradiated to the graphite target can be stabilized, and nanocarbon having a desired property can be stably produced at a high yield.

  In the present invention, the shielding member is disposed so as to cover the window portion from the carbon vapor evaporated from the graphite target. The shielding member may be configured to cover the window portion so as to prevent adhesion of soot-like material obtained from carbon vapor generated from the surface of the graphite target while allowing light emitted from the light source to reach the surface of the graphite target. it can.

  In the present invention, the chamber accommodates the graphite target. However, the entire graphite target need not be accommodated. A part of the graphite target may be accommodated.

  In the present invention, the window portion is an optical member that transmits light emitted from the light source, and can be, for example, a laser light window or a lens. Moreover, the window part is arrange | positioned so that the part may be exposed indoors. The window part may be arranged on the emission end face or the like as a part of the light source, or may be arranged on the wall surface of the chamber in which the graphite target is accommodated as a member independent of the light source.

  Further, in this specification, the “power density” refers to the power density of light actually irradiated on the surface of the graphite target, that is, the power density at the light irradiation site on the surface of the graphite target.

  The manufacturing apparatus of this invention WHEREIN: You may provide the optical member for guide | inducing the said light to the said surface of the said graphite target between the said window part and the said shielding member. By doing so, light can be reliably irradiated onto the surface of the graphite target. Therefore, nanocarbon can be manufactured stably. Further, in the present invention, since the shielding member is provided between the optical member and the graphite target, the soot-like substance is scattered in the direction of the window portion without being collected by the collecting portion and adheres to the surface of the optical member. Can be suppressed. For this reason, the shift | offset | difference of the laser irradiation position in the graphite target surface by the thermal lens effect and the fluctuation | variation of the power density of the light in the surface can be suppressed. Therefore, it is possible to continuously produce nanocarbon having a desired property. Therefore, the yield of nanocarbon can be improved. In addition, since heating of the optical member is suppressed, damage to the optical member can be suppressed and the life of the optical member can be extended. Moreover, the increase in the maintenance cost of the apparatus by replacement | exchange of an optical member can be suppressed. Therefore, an apparatus configuration excellent in durability and productivity can be easily realized.

  According to the present invention, a graphite target, a chamber containing the graphite target, a window provided in a part of the chamber, and a light source for irradiating light on the surface of the graphite target through the window A collection unit for collecting nanocarbon generated from carbon vapor evaporated from the graphite target by the irradiation of light, a reflecting member for reflecting the transmitted light transmitted through the window, and guiding it to the surface of the graphite target; An apparatus for producing nanocarbon is provided.

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

  By doing so, the surface of the graphite target can be irradiated after changing the optical path of the light transmitted through the window. Therefore, it is possible to reliably suppress the soot-like substance from adhering to the window portion.

  In the present invention, the reflecting member can be made of metal, for example. By carrying out like this, the heat dissipation of the surface is ensured suitably. Therefore, even if soot-like substances adhere to the surface, an excessive temperature rise can be suppressed. In the present invention, a cooling mechanism for cooling the reflecting member may be further provided. If it carries out like this, a reflective member can be cooled more reliably. For this reason, the overheating of the reflecting member can be suppressed and its life can be improved. Moreover, nanocarbon can be manufactured stably. In the present invention, a dust scavenging mechanism for removing the soot-like substance attached to the reflecting member may be further provided. In this way, nanocarbon can be produced while removing the soot-like substance at a predetermined timing. For this reason, the yield of nanocarbon can further be improved.

  The nanocarbon manufacturing apparatus of the present invention may further include a shielding member interposed between the reflecting member and the graphite target.

  By doing so, the window portion or the optical member can be more reliably protected from the adhesion of soot-like substances. For this reason, the fall of the yield of nanocarbon can be suppressed. Moreover, the lifetime of the optical member can be prolonged.

  In the nanocarbon manufacturing apparatus of the present invention, the reflecting member may have a light collecting action. By doing so, light can be reliably collected at a predetermined position of the graphite target. For this reason, nanocarbon can be manufactured stably. Moreover, since light can be condensed on the surface of the graphite target without providing an optical member for condensing, nanocarbon can be efficiently produced with a simple configuration. In addition, the reflective member which has a condensing effect | action may be comprised from the single member, and may be comprised by the combination of the several member.

  For example, the reflecting member can be a concave mirror. In the nanocarbon manufacturing apparatus of the present invention, the reflecting member may be a parabolic mirror. In this way, the reflected light obtained by reflecting the light to the concave mirror can be reliably collected at the focal point. Therefore, the reflected light can be more reliably condensed on the surface of the graphite target. Therefore, nanocarbon can be manufactured more stably.

  The nanocarbon production apparatus of the present invention may include target holding means for holding the cylindrical graphite target and rotating the graphite target around a central axis. By carrying out like this, nanocarbon can be manufactured continuously. Therefore, the yield of nanocarbon can be improved.

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

  By carrying out like this, a carbon nanohorn aggregate | assembly can be stably manufactured with a high yield.

  The nanocarbon manufacturing apparatus of the present invention may further include an air intake section that generates an airflow along the light traveling direction from the light source side toward the graphite target side. By so doing, it is possible to more reliably suppress the soot-like substance from moving from the graphite target side toward the light source side and adhering to the window part or the optical member. For this reason, the lifetime of the apparatus can be prolonged even more reliably. In addition, nanocarbon can be produced more stably.

As mentioned above, although the structure of this invention was demonstrated, what combined these structures arbitrarily is effective as an aspect of this invention. Moreover, what converted the expression of this invention into the other category is also effective as an aspect of this invention.
As described above, according to the present invention, by providing a shielding member between the window portion and the graphite target, nanocarbon can be produced with high yield. Moreover, according to the present invention, the lifetime of the nanocarbon production apparatus can be extended.

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

FIG. 1 is a diagram showing a configuration of a nanocarbon production 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 manufacturing apparatus according to an embodiment.
FIG. 4 is a diagram showing a configuration of a nanocarbon manufacturing apparatus according to an embodiment.
FIG. 5 is a diagram showing a configuration of a nanocarbon manufacturing apparatus according to an embodiment.
FIG. 6 is a diagram showing a configuration of a nanocarbon manufacturing apparatus according to an embodiment.
FIG. 7 is a diagram showing a configuration of a nanocarbon manufacturing 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 diagram showing a configuration of a nanocarbon production apparatus according to an example.
FIG. 10 is a diagram showing a configuration of a nanocarbon manufacturing apparatus according to an example.
FIG. 11 is a diagram showing the damage time of the ZnSe window in each apparatus of the example.
FIG. 12 is a diagram showing the relationship between production time and yield of carbon nanohorn aggregates in Examples.

  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 an optical path of light irradiated on the surface of a graphite target is covered with a cover. FIG. 1 is a cross-sectional view showing an example of the configuration of the nanocarbon manufacturing apparatus according to the present embodiment. In the present specification, FIG. 1 and the drawings used for explaining other manufacturing apparatuses are schematic views, and the size of each component does not necessarily correspond to the actual dimensional ratio.

  The nanocarbon production apparatus 125 of FIG. 1 includes a production chamber 107, a nanocarbon recovery chamber 119, and a transport pipe 141 that connects them. 1 has a laser light source 111 that emits laser light 103, a ZnSe plano-convex lens 131, a ZnSe window 133, a cover 167, and a graphite rod 101, and a rotating device 115 that rotates around its central axis. Prepare. Furthermore, the nanocarbon manufacturing apparatus 125 includes an inert gas supply unit 127, a flow meter 129, a vacuum pump 143, and a pressure gauge 145.

  In the nanocarbon manufacturing apparatus 125, the light emitted from the laser light source 111 is collected by a ZnSe plano-convex lens 131 and irradiated onto the graphite rod 101 in the manufacturing chamber 107 through a ZnSe window 133 provided on the wall surface of the manufacturing chamber 107. The 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 simple substance serving as a target for laser beam 103 irradiation. The graphite rod 101 is fixed to a rotating device 115 and can rotate around the central axis. For example, the graphite rod 101 can be rotated so that the portion irradiated with the laser beam 103 on the surface of the graphite rod 101 is 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. By so doing, it is possible to more reliably suppress the generation of return light.

  And the carbon nanohorn aggregate | assembly 117 can be collect | recovered reliably, providing the new irradiation surface used for irradiation of the laser beam 103 stably. By fixing the graphite rod 101 to the rotating device 115, it is possible to rotate it around the central axis. Further, the graphite rod 101 can be configured to be movable in a direction along the central axis, for example.

  The transport pipe 141 communicates with and connects the manufacturing chamber 107 and the nanocarbon recovery chamber 119. The side surface of the graphite rod 101 is irradiated with the laser beam 103 from the laser light source 111, and a nanocarbon recovery chamber 119 is provided in the generation direction of the plume 109 via the transfer tube 141 at that time, and the generated carbon nanohorn aggregate 117 is formed. Is recovered in the nanocarbon recovery chamber 119.

  The plume 109 is generated in the direction perpendicular to the tangent to 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 can be efficiently removed from the nanocarbon recovery chamber. 119, the powder of the carbon nanohorn aggregate 117 can be recovered. For example, when the irradiation angle is 45 °, the transport pipe 141 can be provided in a direction that forms 45 ° with respect to the vertical.

  In the nanocarbon manufacturing apparatus 125, a cylindrical cover 167 that covers the optical path is provided in the manufacturing chamber 107 along the passage path of the laser light 103 from the vicinity of the ZnSe window 133 to the vicinity of the surface of the graphite rod 101. The cover 167 is provided up to the vicinity of the graphite rod 101, and an end of the cover 167 is opened. The laser beam 103 passes through the cover 167 and is irradiated on the surface of the graphite rod 101.

  By providing the cover 167, the soot-like substance obtained from the carbon vapor generated by irradiating the laser beam 103 on the surface of the graphite rod 101 is not attached while ensuring the irradiation path of the light to the graphite rod 101. The ZnSe window 133 can be shielded. Since the attachment of the soot-like substance to the surface of the ZnSe window 133 is suppressed, the absorption of the laser beam 103 on the surface of the ZnSe window 133 is suppressed. Therefore, fluctuations in the power density of the laser beam 103 irradiated on the surface of the graphite rod 101 can be suppressed. Moreover, the excessive temperature rise of the ZnSe window 133 can be suppressed. Therefore, the shift | offset | difference by the thermal lens effect of the irradiation position of the laser beam 103 to the graphite rod 101 surface can be suppressed. Moreover, deterioration of the ZnSe window 133 due to overheating, and accompanying damage or combustion can be suppressed.

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

  The nanocarbon manufacturing apparatus 125 is provided with a transport 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 manufacturing chamber 107. When the surface of the graphite rod 101 is irradiated with the laser beam 103, a plume 109 is generated and emitted from the plume 109, so that the carbon vapor becomes a soot-like substance. In the nanocarbon manufacturing apparatus 125, since the transport pipe 141 is formed in the direction in which the plume 109 is generated, the nanocarbon manufacturing apparatus 125 is reliably guided to the nanocarbon recovery chamber 119 through the transport 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 the tangent to the irradiation position of the laser beam 103 on the surface of the graphite rod 101.

  The nanocarbon manufacturing apparatus 125 is configured to irradiate the side surface of the graphite rod 101 with the laser beam 103 while rotating the graphite rod 101 in the circumferential direction. The laser beam 103 is irradiated in a positional relationship where the direction of the laser beam 103 and the generation direction of the plume 109 do not match. By so doing, the carbon nanohorn aggregate 117 can be efficiently recovered at a position where the irradiation path of the laser beam 103 is not interrupted.

  In the nanocarbon manufacturing apparatus 125, the angle of the plume 109 generated on the side surface of the graphite rod 101 can be predicted in advance. For this reason, the position and angle of the transport pipe 141 can be precisely controlled. Therefore, the carbon nanohorn aggregate 117 can be efficiently manufactured under the conditions described later, and can be reliably recovered.

  Next, the manufacturing method of the carbon nanohorn aggregate 117 using the nanocarbon manufacturing apparatus 125 of FIG. 1 will be specifically described.

  In the nanocarbon manufacturing apparatus 125, as the graphite rod 101, high-purity graphite, for example, round bar-like sintered carbon, compression-molded carbon, or the like can be used.

As the laser beam 103, for example, a high-power CO ₂ gas laser can be used. Irradiation of the laser beam 103 to the graphite rod 101 is performed in a reaction inert gas atmosphere including a rare gas such as Ar or He, for example, an atmosphere of 10 ³ Pa to 10 ⁵ Pa. In addition, it is preferable that the inside of the manufacturing chamber 107 is preliminarily evacuated to, for example, 10 ⁻² Pa or less and then an inert gas atmosphere is provided.

Further, the output, the spot diameter, and the irradiation angle of the laser beam 103 can be adjusted so that the power density of the laser beam 103 on the side surface of the graphite rod 101 is substantially constant, for example, 5 kW / cm ² or more and 25 kW / cm ² or less. preferable.

  The output of the laser beam 103 is, for example, 1 kW or more and 50 kW or less. The pulse width of the laser beam 103 is, for example, 0.5 seconds or more, 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. For this reason, the carbon nanohorn aggregate 117 can be efficiently manufactured. The pulse width of the laser beam 103 is, for example, 1.5 seconds or less, preferably 1.25 seconds or less. By doing so, it is possible to suppress the surface energy density from fluctuating due to excessive heating of the surface of the graphite rod 101 and a decrease in the yield of the carbon nanohorn aggregate. The pulse width of the laser beam 103 is more preferably set to 0.75 seconds or more and 1 second or less. In this way, both the production rate and yield of the carbon nanohorn aggregate 117 can be improved.

  Further, the pause width in the irradiation with the laser beam 103 can be set to, for example, 0.1 seconds or more, and is preferably set to 0.25 seconds or more. By doing so, overheating of the surface of the graphite rod 101 can be more reliably suppressed.

  The laser beam 103 is irradiated so that the irradiation angle is constant. While maintaining the irradiation angle of the laser beam 103 constant, the graphite rod 101 is rotated at a predetermined speed with respect to the central axis thereof, thereby causing the laser beam 103 to have a constant power density in the circumferential direction of the side surface of the graphite rod 101. Irradiation can be continuous. Further, by sliding the graphite rod 101 in the length direction, the laser beam 103 can be continuously irradiated in the length direction of the graphite rod 101 at a constant power density.

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

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

  Moreover, by irradiating the laser beam 103 at 60 ° or less, the generation of amorphous carbon can be suppressed, and the ratio of the carbon nanohorn aggregate 117 in the product, that is, the yield of the carbon nanohorn aggregate 117 can be improved. . The irradiation angle is particularly preferably 45 ° ± 5 °. By irradiation at about 45 °, the ratio of the carbon nanohorn aggregate 117 in the product can be further improved.

  The nanocarbon manufacturing apparatus 125 is configured to irradiate the side surface of the graphite rod 101 with the laser beam 103. For this reason, the irradiation angle to the side surface can be changed by adjusting the height of the graphite rod 101 while the position of the ZnSe plano-convex lens 131 is fixed. 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, and the power density can be made variable and reliably adjusted.

  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 °. For example, the power density can be controlled to be low by setting the irradiation angle to 60 °.

  Further, the spot diameter of the laser beam 103 on the side surface of the graphite rod 101 at the time of irradiation can be, for example, 0.5 mm or more and 5 mm or less.

  Moreover, it is preferable to move the spot of the laser beam 103 at a linear velocity (circumferential velocity) of, for example, 0.01 mm / sec or more and 55 mm / sec or less. When 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. On the other hand, the evaporation of carbon from the surface of the graphite rod 101 occurs because the depth from the surface is small. Limited to area. On the other hand, when 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 evaporation occurs to a region where the depth from the surface of the graphite rod 101 is large. .

  The amount of soot-like substance produced per unit time, that is, the soot-like substance production rate, and the yield of the carbon nanohorn aggregate 117 in the soot-like substance produced are determined by the movement distance of the irradiation position and the carbon in one pulse light irradiation. It is assumed that it depends on the evaporation depth. When the depth at which carbon evaporates is too deep, a product other than the carbon nanohorn aggregate 117 is generated, and the yield decreases. Further, if the depth is too shallow, the carbon nanohorn aggregate 117 is not sufficiently generated. By setting the linear velocity to the above-described conditions, the carbon nanohorn aggregate 117 can be efficiently manufactured with a high yield.

  For example, when irradiating the surface of a graphite target with a diameter of 100 mm with the laser beam 103, the rotating rod 115 rotates the graphite rod 101 with a diameter of 100 mm at a constant speed in the circumferential direction, and the rotational speed is, for example, 0.01 rpm or more and 10 rpm. The linear velocity described above can be realized as follows. Although there is no particular limitation on the rotation direction of the graphite rod 101, the irradiation position is away from the laser beam 103, that is, the direction from the laser beam 103 toward the carrier tube 141 as indicated by an arrow in FIG. It is preferable to rotate it. By doing so, the carbon nanohorn aggregate 117 can be recovered more reliably.

  The soot-like substance recovered in the nanocarbon recovery chamber 119 mainly includes the carbon nanohorn aggregate 117, and is recovered, 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 nanocarbon is produced 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 transport pipe 141. An air flow may be formed along the direction reaching the recovery chamber 119. For example, an air intake section that generates an air flow along the traveling direction of the laser light 103 from the laser light source 111 side toward the graphite rod 101 side may be further provided. In this way, it is possible to more reliably suppress the soot-like substance from adhering to the ZnSe window 133 from the surface of the graphite rod 101. Moreover, since the produced | generated carbon nanohorn aggregate | assembly 117 can be guide | induced more reliably from the conveyance pipe 141 to the nanocarbon collection | recovery chamber 119, the recovery rate of the carbon nanohorn aggregate | assembly 117 can be improved.

  In the nanocarbon manufacturing apparatus 125, the ZnSe plano-convex lens 131 and the ZnSe window 133 are used. However, a ZnSe plano-convex lens may be provided as the ZnSe window 133. That is, in this case, the lens is used as a window for sealing the manufacturing chamber 107 without providing the ZnSe plano-convex lens 131 outside the manufacturing chamber 107. By doing so, an apparatus configuration that is simple and excellent in production efficiency is realized.

  In the apparatus of FIG. 1 and the apparatus described in the following embodiments, the laser light source 111 is provided above the manufacturing chamber 107. The carbon nanohorn aggregate 117 generated by the irradiation with the laser beam 103 is collected in a nanocarbon recovery chamber 119 provided on the side of the manufacturing chamber 107 via the transport pipe 141. In the present embodiment and the following embodiments, the arrangement of the laser light source 111 is not necessarily limited to an aspect provided above the manufacturing chamber 107.

  For example, FIG. 2 is a diagram illustrating another configuration of a nanocarbon manufacturing apparatus having a cover 167. In the apparatus of FIG. 2, a laser light source 111 is provided on the side of the manufacturing chamber 107, and the laser beam 103 is irradiated from the 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 of FIG. 2, the plume 109 is generated in the manufacturing chamber 107 in a direction that forms 45 ° with respect to the vertical upper direction. In the apparatus of FIG. 2, similarly to the apparatus of FIG. 1, the transfer pipe 141 is provided in parallel to the plume generation direction from the vicinity of the surface of the graphite rod 101, and the soot-like substance generated from the plume 109 is provided in the upper part of the manufacturing chamber 107 The nanocarbon recovery chamber 119 is configured to be recovered.

  2, the rotating device 115 has a rotating mechanism that holds the graphite rod 101 and rotates it along the central axis thereof. In the case of the apparatus of FIG. 2 as well, the graphite rod 101 is configured to be able to move in the direction of the central axis as in the apparatus of FIG.

  In the apparatus of FIG. 1, a cover 167 that covers the optical path of the laser beam 103 emitted from the laser light source 111 is provided as a shielding member for protecting the ZnSe window 133. Is not limited to this.

  For example, FIG. 3 shows an apparatus having a configuration in which a partition wall 179 is provided instead of the cover 167 of the nanocarbon manufacturing apparatus 125 of FIG. Other configurations are the same as those of the nanocarbon manufacturing apparatus 125. In the apparatus of FIG. 3, a partition wall 179 is provided in the manufacturing chamber 107. The partition wall 179 partitions the manufacturing 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 through and reaching the graphite rod 101. For this reason, laser light irradiation to the graphite rod 101 is possible. By providing the partition wall 179, it is possible to shield the soot-like substance generated from the graphite rod 101 side from moving to the ZnSe window 133 side. For this reason, it can suppress that a soot-like substance adheres to the ZnSe window 133 surface.

  In the apparatus shown in FIGS. 1 to 3, a ZnSe window 133 is provided as a window on the wall surface of the manufacturing chamber 107. However, the window has this configuration as long as a part of the window is exposed in the manufacturing chamber 107. It is not limited. For example, a laser light source 111 having a window on the emission end face may be disposed in the manufacturing chamber 107. In this case, the space between the laser light source 111 and the graphite rod 101 is shielded by a shielding member such as the cover 167 or the partition 179, so that the attachment of the soot-like substance to the window of the laser light source 111 is suppressed. A ZnSe plano-convex lens 131 may be provided in the manufacturing chamber 107. In this case, by adhering the space between the ZnSe plano-convex lens 131 and the graphite rod 101 with, for example, the cover 167 or the partition 179, adhesion of soot-like substances to the surface of the ZnSe plano-convex lens 131 can be suppressed.

(Second embodiment)
The present embodiment relates to a nanocarbon manufacturing apparatus configured to irradiate the surface of the graphite rod 101 after irradiating the light emitted from the light source 111 without directly irradiating the surface of the graphite rod 101, changing the optical path.

  FIG. 4 is a cross-sectional view showing the nanocarbon production apparatus 173 according to the present embodiment as viewed from the side. In this embodiment, the same code | symbol is attached | subjected to the component similar to the nanocarbon manufacturing apparatus 125 described in 1st embodiment, and description is abbreviate | omitted suitably.

  In the nanocarbon manufacturing apparatus 125 (FIG. 1), the laser light 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, and then from the ZnSe window 133. In the nanocarbon manufacturing apparatus 173 shown in FIG. 4, the laser light 103 emitted from the laser light source 111 is not condensed and enters the manufacturing chamber 107 from the ZnSe window 133, whereas the manufacturing process is performed in the manufacturing chamber 107. Irradiated. Since the nanocarbon manufacturing 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 manufacturing chamber 107, and is further parabolic. Reflected by the 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 manufacturing apparatus 173, the laser beam 103 incident on the manufacturing chamber 107 through the ZnSe window 133 is not directly irradiated on the surface of the graphite rod 101, but the plane mirror 169 and the parabolic mirror. After being reflected twice by 171 to change the optical path, the surface of the graphite rod 101 is irradiated. In addition, since the nanocarbon manufacturing apparatus 173 passes through the plane mirror 169 and the parabolic mirror 171, the length of the optical path from the ZnSe window 133 to the graphite rod 101 can be increased as compared with the nanocarbon manufacturing apparatus 125.

  Therefore, the plume 109 generated from the surface of the graphite rod 101 and the soot-like substance obtained from the plume 109 are prevented from adhering to the ZnSe window 133. Therefore, even if the nanocarbon manufacturing apparatus 173 is used for a long time, a change in the power density of the laser beam 103 irradiated on the surface of the graphite rod 101 can be suppressed. For this reason, the fall of the yield of the carbon nanohorn aggregate 117 can be suppressed, and the carbon nanohorn aggregate 117 can be stably continuously produced. In addition, the device life of the nanocarbon production device 173 can be extended.

  In the nanocarbon manufacturing 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. Moreover, the surface of the plane mirror 169 and the parabolic mirror 171 may be coated with Au or Mo, for example. By using such a material, damage to the plane mirror 169 or the parabolic mirror 171 can be suppressed.

  In the nanocarbon manufacturing apparatus 173, the light emitted from the laser light source 111 is reflected twice and then irradiated onto the surface of the graphite rod 101. However, the light emitted from the laser light source 111 changes the optical path. The number of reflections is not particularly limited as long as it reaches the surface of the rear graphite rod 101, and can be configured to reflect once, or can be configured to reflect three or more times and irradiate the graphite rod 101. Good.

  In the nanocarbon manufacturing 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. For example, the shape of the reflecting mirror is not limited to the parabolic mirror 171, and for example, a concave mirror having another shape can be used. Moreover, you may condense on the surface of the graphite rod 101 combining several reflective mirrors.

(Third embodiment)
The present embodiment relates to another configuration of the nanocarbon manufacturing apparatus. 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 will be omitted as appropriate.

  FIG. 5 is a cross-sectional view showing the nanocarbon production apparatus 175 according to the present embodiment as viewed from the side. The basic device configuration of the nanocarbon manufacturing apparatus 175 is the same as that of the nanocarbon manufacturing apparatus 173 (FIG. 4), but the nanocarbon manufacturing apparatus 175 is provided with a cover 167 for protecting the passage path of the laser light 103. This is different from the nanocarbon manufacturing apparatus 173.

  By providing the cover 167, as described in the first embodiment, it is possible to further reliably prevent the soot-like substance generated from the plume 109 from directly attaching to the ZnSe window 133. Further, it is possible to more reliably prevent soot-like substances from adhering to the surface of the plane mirror 169 or the parabolic mirror 171. For this reason, the irradiation position of the laser beam 103 or the power density fluctuation 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 apparatus can be further prolonged.

  5 has a structure in which a ZnSe window 133 is provided inside the manufacturing chamber 107 because the cover 167 is provided in contact with the wall surface of the manufacturing chamber 107, but an inert gas is used. The position of the ZnSe window 133 is not limited to the inside of the manufacturing chamber 107, and may be provided on the wall surface of the manufacturing chamber 107, for example. For example, FIG. 6 is a diagram showing a nanocarbon production apparatus 176 in which a ZnSe window 133 is provided on the wall surface of the production chamber 107.

(Fourth embodiment)
In the above embodiment, the case where a graphite rod is used has been described as an example. However, in any 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. Good.

  For example, FIG. 7 is a diagram showing an apparatus configuration when a sheet-like graphite target is used in the nanocarbon production apparatus 175 (FIG. 5) described in the third embodiment.

  In the nanocarbon manufacturing apparatus 177 of 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 unit 153 on the target supply plate 135. The plate holding part 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, and the relative position between the irradiation position of the laser beam 103 and the surface of the graphite target 139 moves. .

  For example, threads (not shown) are formed on the bottom surface of the target supply plate 135 and the surface of the plate holding portion 137 so that the target supply plate 135 can move from the upper left to the lower right in FIG. can do. Further, 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 on the bottom of the target holding portion 153 so that the groove can be slid. By engaging, the target holding unit 153 and the graphite target 139 held by the target holding unit 153 can be configured to be movable in a direction perpendicular to the paper surface of FIG.

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

  Further, when the graphite target is formed into a sheet shape or a rod shape, the thickness of the graphite target is vaporized when irradiated with the laser beam 103 once or several times, so that the carbon nanohorn can be used up. The yield of the aggregate 117 can be further improved. This is because once the laser beam 103 is irradiated, the surface of the graphite rod 101 becomes rough, and when the laser beam 103 is irradiated again, power density fluctuation occurs. This is because the smaller the number of times the laser beam 103 is irradiated, the more stable the carbon nanohorn aggregate 117 can be produced.

  The present invention has been described based on the embodiments. It should be understood by those skilled in the art that these embodiments are illustrative and that various modifications are possible, and that such modifications are within the scope of the present invention.

  In the apparatus according to the above embodiment, the soot-like substance obtained by the irradiation with the laser beam 103 is recovered in the nanocarbon recovery chamber 119, but is deposited and recovered on an appropriate substrate. In addition, it can be collected by a method of collecting fine particles using a dust bag. Alternatively, the inert gas can be circulated in the reaction vessel, and the soot-like substance can be recovered by the flow of the inert gas.

  In the above embodiment, conditions such as the power density of the irradiation light on the surface of the graphite target, the pulse width, the resting width, or the moving speed of the graphite target when the carbon nanohorn aggregate 117 is manufactured depend on the shape and purpose of the graphite target. It can be appropriately selected according to the shape of the carbon nanohorn aggregate 117. In addition, the shape, diameter, length, tip shape, spacing between carbon molecules and carbon nanohorns, etc. of the carbon nanohorns constituting the carbon nanohorn aggregate 117 are variously controlled according to the irradiation conditions of the laser beam 103, etc. Is possible.

  In the apparatus shown in the second to fourth embodiments (FIGS. 4 to 7), the ZnSe window 133 is provided on the wall surface of the manufacturing chamber 107 as a window. If it is the aspect which exposed the part, it will not be limited to this structure. For example, a laser light source 111 having a window on the emission end face may be disposed in the manufacturing chamber 107. In this case, the light emitted from the laser light source 111 is reflected by, for example, a reflecting mirror such as a plane mirror 169 or a parabolic mirror 171 and then reaches the surface of the graphite rod 101, soot to the window of the laser light source 111. Adherence of particulate matter is suppressed. 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, for example, a reflecting mirror such as a plane mirror 169 or a parabolic mirror 171 and then reaches the surface of the graphite rod 101 to reach the surface of the ZnSe plano-convex lens 131. It is possible to suppress adhesion of soot-like substances.

  Moreover, in the apparatus (FIGS. 4 to 7) shown in the second to fourth embodiments, a cooling mechanism for cooling the parabolic mirror 171 may be further provided. By cooling the parabolic mirror 171, excessive heating is suppressed even when soot-like substances adhere to the surface of the parabolic mirror 171, so that the life of the apparatus can be further extended. Further, a dust scavenging mechanism for removing soot-like substances attached to the surface of the parabolic mirror 171 may be provided. With such a configuration, even when a soot-like substance adheres to the surface of the parabolic mirror 171, it can be removed at an appropriate timing. Therefore, the power of light irradiated on the surface of the graphite rod 101 It is possible to control the density more reliably so that the density becomes a constant value. For this reason, the yield of the carbon nanohorn aggregate can be further improved. Moreover, the lifetime of the apparatus can be further extended. Here, the cooling mechanism and the dust scavenging mechanism have been described by taking the case of the parabolic mirror 171 as an example, but these mechanisms can also be provided for the plane mirror 169 as necessary.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these.

  In this example, the carbon nanohorn aggregate 117 was manufactured by a laser ablation method using the nanocarbon manufacturing apparatus 126 shown in FIG. 2 and the nanocarbon manufacturing apparatus shown in FIG. 8, FIG. 9, and FIG. However, FIGS. 8 and 9 are configurations in which the laser beam 103 is incident from the side surface of the manufacturing chamber 107 in the nanocarbon manufacturing apparatus 173 of FIG. 4 and the nanocarbon manufacturing apparatus 175 of FIG. This is a device. The apparatus of FIG. 10 is a nanocarbon manufacturing apparatus having a configuration similar to that of the nanocarbon manufacturing apparatus 126 of FIG.

Sintered round bar carbon having a diameter of 100 mm as a solid carbon material is placed in a vacuum vessel, and after the inside of the vessel is evacuated to 10 ⁻² Pa, Ar gas has an atmospheric pressure of 1.01325 × 10 ⁵ Pa. Introduced as follows. Subsequently, the solid carbon material was irradiated with high-power CO ₂ laser light 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 1 sec, the rest width was 250 msec, and the solid carbon material was rotated at 6 rpm, and the laser beam was irradiated so that the irradiation angle was 45 °. Laser irradiation was performed until the ZnSe window was broken, and the time until the ZnSe window was broken was measured in each apparatus.

  Further, 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 apparatus. In FIG. 11, “ZnSe” is the experimental result for the apparatus of FIG. In addition, the “ZnSe—nanocarbon adhesion prevention cone”, “parabolic mirror”, and “parabolic mirror—nanocarbon adhesion prevention cone” are the nanocarbons shown in FIG. 2, FIG. 8, and FIG. 9, respectively. It is an experimental result about a manufacturing apparatus.

  From FIG. 11, it was found that the durability of the ZnSe window 133 is increased by providing the cover 167 in the device configuration for condensing using the ZnSe plano-convex lens 131. In addition, it has been clarified that by using the parabolic mirror 171 to collect light, the endurance time of the ZnSe window 133 is remarkably increased, and further, the cover 167 is further provided.

  From this result, it was confirmed that the life of the apparatus can be extended by adopting a configuration in which the surface of the graphite rod 101 is irradiated after reflecting and condensing the laser beam 103 using the parabolic mirror 171.

  FIG. 12 is a diagram showing the relationship between the manufacturing time and the yield of the carbon nanohorn aggregate 117 for the “ZnSe” and “parabolic mirror” devices in FIG. 11, that is, the devices in FIGS. . From FIG. 12, in the apparatus of FIG. 10, the yield of the carbon nanohorn aggregate 117 decreases as the manufacturing 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 it can be seen that the yield is almost constant. For this reason, 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, thereby stably stabilizing the carbon nanohorn aggregate. It became clear that it was possible to produce with high yield.

Claims (9)

A graphite target,
A chamber containing the graphite target;
A window provided in a part of the chamber;
A light source that irradiates light onto the surface of the graphite target through the window;
A recovery unit for recovering nanocarbon generated from carbon vapor evaporated from the graphite target by the light irradiation;
A shielding member interposed between the window portion and the graphite target;
An apparatus for producing nanocarbon, comprising: In the nanocarbon manufacturing apparatus 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 portion and the shielding member. The nanocarbon manufacturing apparatus according to claim 1 or 2, wherein the optical member includes a reflecting member. A graphite target,
A chamber containing the graphite target;
A window provided in a part of the chamber;
A light source that irradiates light onto the surface of the graphite target through the window;
A recovery unit for recovering nanocarbon generated from carbon vapor evaporated from the graphite target by the light irradiation;
A reflecting member for reflecting the transmitted light transmitted through the window and guiding it to the surface of the graphite target;
An apparatus for producing nanocarbon, comprising: 5. The nanocarbon manufacturing apparatus according to claim 4, further comprising a shielding member interposed between the reflecting member and the graphite target. The nanocarbon manufacturing apparatus according to any one of claims 3 to 5, wherein the reflecting member has a light condensing function. The nanocarbon manufacturing apparatus according to any one of claims 3 to 6, wherein the reflecting member is a parabolic mirror. The nanocarbon production apparatus according to any one of claims 1 to 7, further comprising target holding means for holding the cylindrical graphite target and rotating the graphite target around a central axis. Nanocarbon manufacturing equipment. The nanocarbon manufacturing apparatus according to any one of claims 1 to 8, wherein the nanocarbon is a carbon nanohorn aggregate.

Images