Metal nanoparticle manufacturing equipment

Abstract

To provide a metal nanoparticle production device capable of continuously producing metal nanoparticles of desired particle size for a long period of time.SOLUTION: A metal nanoparticle production device according to the present invention comprises a container containing a liquid, a first metal body, one end of which is disposed in the container and is composed of metal as a raw material for metal nanoparticles, a second metal body, one end of which is disposed of in the container so as to face one end of the first metal body, a high-frequency supply device that supplies a high-frequency to the liquid through one end of the first metal body or one end of the second metal body and generates plasma between the one end of the first metal body and the one end of the second metal body, a feeding device that feeds the first metal body or the second metal body so that the one end of the first metal body and the one end of the second metal body are close to each other, a temperature detection unit that detects the temperature of the one end of the first metal body and the one end of the second metal body, and a control unit that controls the feed rate of the feeding device based on the temperature detected by the temperature detection unit.SELECTED DRAWING: Figure 1

Description

【Technical Field】 【0001】 The present invention relates to a metal nanoparticle manufacturing apparatus. 【Background Art】 【0002】 As a conventional method for manufacturing metal nanoparticles, for example, a method is known in which one end of a raw material metal body serving as a raw material for metal nanoparticles and one end of an electrode conductor are arranged in a liquid so as to face each other, and a high-temperature plasma is generated between both ends. According to this method, a part of the raw material metal body is evaporated by the plasma, and a part of the evaporated raw material metal body is cooled by the liquid, thereby obtaining metal nanoparticles. 【0003】 As a metal nanoparticle manufacturing apparatus using such a conventional method for manufacturing metal nanoparticles, for example, the manufacturing apparatus of Patent Document 1 is known. Patent Document 1 describes a manufacturing apparatus provided with a feeding device that feeds one end of a raw material metal body to one end of an electrode conductor, and configured to continuously manufacture metal nanoparticles while maintaining the distance between both ends. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 International Publication No. 2012 / 147334 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 However, the metal nanoparticle manufacturing apparatus of Patent Document 1 still has room for improvement from the viewpoint of continuously manufacturing metal nanoparticles having a desired particle size for a longer time. 【0006】 Therefore, an object of the present invention is to solve the above problems and provide a metal nanoparticle manufacturing apparatus capable of continuously manufacturing metal nanoparticles having a desired particle size for a longer time. 【Means for Solving the Problems】 【0007】 To achieve the aforementioned objective, the present invention is configured as follows. According to the present invention, a container for holding liquid, One end of the first metal body is placed inside the container and is made of a metal that serves as a raw material for metal nanoparticles, A second metal body is disposed inside the container such that one end of the first metal body faces the other end of the first metal body, A high-frequency supply device that supplies high frequency to the liquid via one end of the first metal body or one end of the second metal body, and generates plasma between one end of the first metal body and one end of the second metal body, A feeding device that feeds the first metal body or the second metal body so that one end of the first metal body and one end of the second metal body are brought close together, A temperature detection unit for detecting the temperature of one end of the first metal body and one end of the second metal body, A control unit that controls the feed rate of the feed device based on the temperature detected by the temperature detection unit, We provide a metal nanoparticle manufacturing apparatus equipped with the following features. [Effects of the Invention] 【0008】 According to the metal nanoparticle manufacturing apparatus of the present invention, metal nanoparticles of a desired particle size can be manufactured continuously for a longer period of time. [Brief explanation of the drawing] 【0009】 [Figure 1] This is a block diagram of a metal nanoparticle manufacturing apparatus according to an embodiment of the present invention. [Figure 2] Figure 1 is a side view of the metal nanoparticle manufacturing apparatus. [Figure 3] Figure 1 is a partially enlarged side view of the metal nanoparticle manufacturing apparatus. [Figure 4A] This is a TEM image of gold nanoparticles produced by a metal nanoparticle manufacturing apparatus according to an embodiment of the present invention. [Figure 4B] This is an enlarged image of Figure 4A. [Figure 5]This graph shows the relationship between the needle valve reading and the water supply volume when the pressure inside the container is 250 hPa. [Modes for carrying out the invention] 【0010】 (Knowledge that formed the basis of this invention) The inventors of this invention have diligently investigated how to continuously produce metal nanoparticles of a desired particle size for a longer period of time, and have obtained the following findings. 【0011】 To generate plasma in a liquid, it is necessary to continuously generate a discharge within the bubbles created by evaporating the liquid. In the manufacturing process of metal nanoparticles, if a portion of the raw metal material decreases due to evaporation, increasing the distance between one end of the raw metal material and one end of the electrode conductor, dielectric breakdown becomes less likely, the discharge becomes discontinuous, and the plasma is more likely to disappear. In this case, it is not possible to continuously manufacture metal nanoparticles of the desired particle size for a longer period of time. 【0012】 In contrast, the manufacturing apparatus described in Patent Document 1 is equipped with a feeding device that feeds one end of the raw material metal body to one end of the electrode conductor, making it possible to continuously manufacture metal nanoparticles while maintaining the distance between the two ends. 【0013】 On the other hand, in radiotherapy, for example, it is known that by introducing an X-ray-opaque lesion identification target into the patient's body and irradiating the lesion identification target, radiation exposure to normal areas can be reduced, thereby enhancing the therapeutic effect. Gold (Au) particles are used as lesion identification targets. The smaller the particle size of the gold particles, the less burden it places on the patient when introduced into the body (minimally invasive). For this reason, there is a demand for the production of gold particles on the nano-order (e.g., 5 nm to 10 nm). 【0014】 The manufacturing apparatus of Patent Document 1 is configured to manufacture metal nanoparticles with relatively low boiling points such as magnesium and zinc. Therefore, the feeding speed of the feeding device is set based on the power for generating plasma, and is set within the range of 1.4 mm / min to 88 mm / min. When attempting to manufacture metal nanoparticles with a high boiling point such as gold using the manufacturing apparatus of this Patent Document 1, since the reduction rate of the raw material metal body by plasma is minute, it is impossible to maintain the distance between one end of the raw material metal body and one end of the electrode conductor more precisely. 【0015】 Also, when manufacturing gold nanoparticles, as the manufacturing progresses, the color of the liquid changes to a dark purple. Therefore, it is difficult to measure the distance between one end of the raw material metal body and one end of the electrode conductor based on the appearance. 【0016】 Therefore, as a result of intensive studies by the present inventors, it has been found that by controlling the feeding speed of the feeding device based on the temperatures of one end of the raw material metal body (first metal body) and one end of the electrode conductor (second metal body), the distance between them can be maintained more precisely. Based on this new finding, the present inventors have arrived at the following invention. 【0017】 According to a first aspect of the present invention, a container for containing a liquid, a first metal body having one end disposed within the container and made of a metal that is a raw material for metal nanoparticles, a second metal body having one end disposed within the container so as to face one end of the first metal body, a high-frequency supply device that supplies high-frequency waves to the liquid through one end of the first metal body or one end of the second metal body and generates plasma between one end of the first metal body and one end of the second metal body, a feeding device that feeds out the first metal body or the second metal body so that one end of the first metal body and one end of the second metal body approach each other, a temperature detection unit that detects the temperatures of one end of the first metal body and one end of the second metal body, a control unit that controls the feeding speed of the feeding device based on the detected temperature of the temperature detection unit, We provide a metal nanoparticle manufacturing apparatus equipped with the following features. 【0018】 According to a second aspect of the present invention, the temperature detection unit detects the temperature based on light generated at one end of the first metal body and one end of the second metal body, providing a metal nanoparticle manufacturing apparatus as described in the first aspect. 【0019】 According to a third aspect of the present invention, the temperature detection unit is A light-collecting device that acquires light generated at one end of the first metal body and one end of the second metal body, A spectroscopic measuring device that spectrally measures the light acquired by the aforementioned light-collecting device, The present invention provides a metal nanoparticle manufacturing apparatus according to the first or second embodiment, comprising the above. 【0020】 According to a fourth aspect of the present invention, a metal nanoparticle manufacturing apparatus according to any one of the first to third aspects is provided, further comprising a vacuum device for reducing the pressure inside the container. 【0021】 According to a fifth aspect of the present invention, the container further comprises a liquid refilling section for refilling the container with liquid, The present invention provides a metal nanoparticle manufacturing apparatus according to a fourth embodiment, wherein the liquid replenishment unit is configured to replenish the liquid in the container by the vacuum device reducing the pressure inside the container. 【0022】 According to a sixth aspect of the present invention, the metal nanoparticle manufacturing apparatus according to the fifth aspect is provided, wherein the liquid replenishment unit includes a flow regulator capable of adjusting the flow rate of the liquid supplied into the container. 【0023】 According to a seventh aspect of the present invention, the feeding device is A ball screw attached to the first metal body or the second metal body, A stepping motor that rotates the aforementioned ball screw around its axis, The present invention provides a metal nanoparticle manufacturing apparatus according to any one of the first to sixth embodiments, comprising the above. 【0024】 According to an eighth aspect of the present invention, the control unit intermittently drives the stepping motor when the temperature detected by the temperature detection unit is near the boiling point of the first metal body, thereby feeding out the first metal body or the second metal body at a feed rate of 1 μm / min or more and 15 μm / min or less, as described in the seventh aspect of the present invention. 【0025】 According to the ninth aspect of the present invention, the second metal body is composed of a metal that serves as a raw material for metal nanoparticles, and the present invention provides a metal nanoparticle manufacturing apparatus according to any one of the first to eighth aspects. 【0026】 Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these embodiments. Furthermore, substantially identical components are denoted by the same reference numerals in the drawings. 【0027】 Furthermore, for the sake of clarity, the following uses terms indicating directions such as "up," "down," and "side," assuming the conditions during normal use. However, this does not mean that the usage conditions of the metal nanoparticle manufacturing apparatus according to the present invention are limited. 【0028】 (Embodiment) The overall configuration of the metal nanoparticle manufacturing apparatus according to an embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1 is a block diagram of the metal nanoparticle manufacturing apparatus according to this embodiment. Figure 2 is a side view of the metal nanoparticle manufacturing apparatus of Figure 1. Figure 3 is a partially enlarged side view of the metal nanoparticle manufacturing apparatus of Figure 1. 【0029】 As shown in Figure 1, the metal nanoparticle manufacturing apparatus according to this embodiment comprises a container 1 for containing liquid L, and a first metal body 2 and a second metal body 3 arranged inside the container 1. 【0030】 Container 1 is a reaction vessel for containing liquid L and generating plasma in liquid L. Container 1 is sealed except for piping and other components connected to each part and device. The liquid L contained in container 1 is, for example, water or an organic solvent such as alcohol. 【0031】 The first metal body 2 has one end 2A positioned inside the container 1. In this embodiment, the first metal body 2 is formed in a rod shape and is positioned to extend vertically through the upper wall of the container 1. The first metal body 2 is made of a metal that serves as the raw material for metal nanoparticles. In this embodiment, the first metal body 2 is made of gold (Au). The diameter of the first metal body 2 is, for example, 3 mm. 【0032】 The second metal body 3 is positioned inside the container 1 such that one end 3A faces the one end 2A of the first metal body 2. In this embodiment, the second metal body 3 is formed in a rod shape and is positioned to extend vertically through the bottom wall of the container. The second metal body 3 is made of a metal that serves as the raw material for metal nanoparticles. In this embodiment, the second metal body 3 is made of gold (Au), similar to the first metal body 2. The diameter of the second metal body 3 is, for example, 3 mm. 【0033】 A high-frequency supply device 4 is connected to the first metal body 2 and the second metal body 3. The high-frequency supply device 4 is a device that supplies high frequency to the liquid L via one end 2A of the first metal body 2 or one end 3A of the second metal body 3, and generates plasma between one end 2A of the first metal body 2 and one end 3A of the second metal body 3. In this embodiment, the high-frequency supply device 4 comprises a high-frequency power supply 41 and a regulator 42, and is connected to the other end portion of the first metal body 2 that protrudes outside the container 1 and the other end portion of the second metal body 3 that protrudes outside the container 1. The other end portion of the first metal body 2 is connected to the GND terminal, which is the reference potential of the high-frequency supply device 4. The other end portion of the second metal body 3 is connected to the high-frequency output terminal of the high-frequency supply device 4. 【0034】 Furthermore, a feeding device 5 is connected to the other end of the first metal body 2, which feeds the first metal body 2 so that one end 2A of the first metal body 2 and one end 3A of the second metal body 3 are brought closer together. The feeding device 5 is configured to feed the first metal body 2 in fine increments of several μm / min to several tens of μm / min. In this embodiment, the feeding device 5 includes a stepping motor 51 and a ball screw 52. The stepping motor 51 rotates the ball screw 52 around its axis. The ball screw 52 is attached to the first metal body 2. When the stepping motor 51 is driven, the ball screw 52 rotates around its axis, and the first metal body 2 connected to the ball screw 52 is fed downward. 【0035】 Furthermore, the metal nanoparticle manufacturing apparatus according to this embodiment includes a temperature detection unit 6, a depressurization device 7, a liquid replenishment unit 8, and a control unit 9. 【0036】 The temperature detection unit 6 detects the temperatures of one end 2A of the first metal body 2 and one end 3A of the second metal body 3. In this embodiment, the temperature detection unit 6 detects the temperature based on the light generated at one end 2A of the first metal body 2 and one end 3A of the second metal body 3. More specifically, the temperature detection unit 6 considers one end 2A of the first metal body 2 and one end 3A of the second metal body 3 as black bodies, spectrally measures the blackbody radiation from these black bodies, and detects the temperature of the object to be measured based on the peak wavelength of the obtained blackbody radiation spectrum. 【0037】 In this embodiment, the temperature detection unit 6 includes a light collection device 61 that acquires light generated at one end 2A of the first metal body 2 and one end 3A of the second metal body 3, and a spectroscopic measuring device 62 that spectrally measures the light acquired by the light collection device 61. As shown in Figure 3, the light collection device 61 includes a light guide rod 611 positioned near one end 2A of the first metal body 2 and one end 3A of the second metal body 3, and an optical fiber 612 that sends the light incident on the light guide rod 611 to the spectroscopic measuring device 62. The light guide rod 611 is, for example, quartz glass. The spectroscopic measuring device 62 spectrally measures the light sent through the optical fiber 612 and calculates the temperature of the object to be measured from the peak wavelength of the obtained blackbody radiation spectrum using the following formula based on Planck's law. 【0038】 【number】 【0039】 In the above equation, λ is the peak wavelength (m) of the blackbody radiation spectrum. h is Planck's constant, 6.626 × 10⁻¹⁶. -34 (J·s). c is the speed of light, 299,792,458 (m / s). k is the Boltzmann constant, 1.38 × 10⁻¹⁰. -23 (J / K) 【0040】 The depressurization device 7 is a device that reduces the pressure inside the container 1. By reducing the pressure inside the container 1 with the depressurization device 7, the boiling point of the liquid L is lowered, making it easier for bubbles to form between one end 2A of the first metal body 2 and one end 3A of the second metal body 3, thereby enabling more stable plasma generation. In this embodiment, the depressurization device 7 includes a vacuum pump 71 and a pressure regulator 72. The vacuum pump 71 sucks air from inside the container 1 to reduce the pressure inside the container 1. The pressure regulator 72 adjusts the pressure inside the container 1. 【0041】 The liquid replenishment unit 8 is for replenishing liquid L in the container 1. When plasma is generated in the container 1, the heat of the plasma causes the liquid L to evaporate. When the liquid L evaporates and one end 2A of the first metal body 2 is exposed to the air, it becomes impossible to collect the generated nanoparticles. The liquid replenishment unit 8 is provided to prevent this. In this embodiment, the liquid replenishment unit 8 is configured to replenish liquid L in the container 1 by the depressurization device 7 reducing the pressure inside the container 1. 【0042】 More specifically, the liquid replenishment unit 8 includes a flow regulator 81 capable of adjusting the flow rate of liquid L supplied into container 1, and a liquid replenishment container 82 that contains the replenishment liquid L. The flow regulator 81 includes a stop valve 811 and a needle valve 812. The stop valve 811 is a valve that can open and close the fluid passage from the liquid replenishment container 82 to container 1. The needle valve 812 is a valve that can adjust the opening ratio of the fluid passage from the liquid replenishment container 82 to container 1. When manufacturing metal nanoparticles, the stop valve 811 is opened. In this state, the depressurization device 7 reduces the pressure inside container 1, creating a pressure difference between container 1 and liquid replenishment container 82, and this pressure difference causes liquid L in liquid replenishment container 82 to move into container 1. By adjusting the opening ratio of the passage with the needle valve 812, the amount of liquid L in liquid replenishment container 82 that moves into container 1 (replenishment amount) can be adjusted. 【0043】 The control unit 9 controls the feed speed of the feed device 5 based on the temperature detected by the temperature detection unit 6. In this embodiment, the control unit 9 includes a PC (personal computer) 91 and a motor driver 92. The PC 91 receives the temperature detected by the temperature detection unit 6 and transmits a command based on the detected temperature to the motor driver 92. The motor driver 92 controls the drive of the stepping motor 51 based on the command from the PC 91. 【0044】 In this embodiment, when the temperature detected by the temperature detection unit 6 is near the boiling point of the first metal body 2, the control unit 9 intermittently drives the stepping motor 51 to feed the first metal body 2 at a feed rate of 1 μm / min or more and 15 μm / min or less. When the distance between one end 2A of the first metal body 2 and one end 3A of the second metal body 3 is large, the energy density of the plasma decreases and the temperature becomes lower. In this case, the temperature detected by the temperature detection unit 6 becomes lower than the boiling point of the first metal body 2. At this time, the control unit 9 drives the stepping motor 51 continuously or intermittently to feed the first metal body 2 at a faster feed rate. 【0045】 Furthermore, in this embodiment, as shown in Figure 3, a thermometer T is provided so as to be in contact with the liquid L inside the container 1. The thermometer T is provided to predict the amount of evaporation of the liquid L by detecting the temperature of the liquid L inside the container 1. 【0046】 According to the metal nanoparticle manufacturing apparatus of this embodiment, the control unit 9 is configured to control the feed rate of the feed device 5 based on the temperatures of one end 2A of the first metal body 2 and one end 3A of the second metal body 3. With this configuration, the distance between one end 2A of the first metal body 2 and one end 3A of the second metal body 3 can be maintained more precisely. As a result, metal nanoparticles of a desired particle size can be manufactured continuously for a longer period of time. 【0047】 Furthermore, in the metal nanoparticle manufacturing apparatus according to this embodiment, the temperature detection unit 6 is configured to detect the temperature based on the light generated at one end 2A of the first metal body 2 and one end 3A of the second metal body 3. With this configuration, the temperature can be detected more accurately even if the boiling point of the metal used as the raw material for the metal nanoparticles is high. 【0048】 Furthermore, the metal nanoparticle manufacturing apparatus according to this embodiment is equipped with a vacuum device 7 that reduces the pressure inside the container 1. With this configuration, the vacuum device 7 reduces the pressure inside the container 1, which lowers the boiling point of the liquid L, making it easier for bubbles to form between one end 2A of the first metal body 2 and one end 3A of the second metal body 3, and enabling more stable plasma generation. 【0049】 Furthermore, the metal nanoparticle manufacturing apparatus according to this embodiment includes a liquid replenishment unit 8 for replenishing liquid L in the container 1, and the liquid replenishment unit 8 is configured to replenish liquid L in the container 1 by reducing the pressure inside the container 1 using a depressurization device 7. With this configuration, there is no need to provide a device that forcibly moves the liquid L, such as a pump, so it is possible to make the apparatus smaller and reduce costs. 【0050】 Furthermore, according to the metal nanoparticle manufacturing apparatus of this embodiment, the second metal body 3 is composed of a metal that serves as a raw material for metal nanoparticles, similar to the first metal body 2. This configuration makes it possible to suppress the inclusion of impurities other than the raw material metal in the manufactured metal nanoparticles. When the first metal body 2 and the second metal body 3 are different metals, it is preferable that the boiling point of the first metal body 2 is sufficiently higher than the boiling point of the second metal body 3. When the boiling points of the first metal body 2 and the second metal body 3 are relatively close, or when the boiling point of the first metal body 2 is lower than the boiling point of the second metal body 3, the proportion of metal nanoparticles produced from the second metal body 3 will be higher. When the first metal body 2 and the second metal body 3 are the same type of metal, the proportion of metal nanoparticles produced from the first metal body 2 and the second metal body 3 will be approximately the same. 【0051】 It should be noted that the present invention is not limited to the embodiments described above, and can be implemented in various other forms. For example, in the above description, the first metal body 2 and the second metal body 3 were arranged to be aligned in a straight line in the vertical direction, but the present invention is not limited to this. For example, the first metal body 2 and the second metal body 3 may be arranged at right angles to each other. It is sufficient that one end 2A of the first metal body 2 and one end 3A of the second metal body 3 are close to each other and arranged so that plasma is generated between them. 【0052】 Furthermore, it is preferable that the first metal body 2 is positioned perpendicular or approximately perpendicular to the surface of the liquid L. In this case, bubbles generated between one end 2A of the first metal body 2 and one end 3A of the second metal body 3 are more likely to remain between them, as the bottom of the end 2A of the first metal body 2 acts as a barrier. As a result, plasma can be generated more stably between the end 2A of the first metal body 2 and one end 3A of the second metal body 3. In addition, it is preferable that the bottom of the end 2A of the first metal body 2 has a shape (e.g., a flat surface) or size that facilitates the retention of bubbles. 【0053】 Furthermore, it is preferable that the outer surface of the first metal body 2 is covered with an insulating material to prevent discharge from occurring in unintended areas. Similarly, it is preferable that the outer surface of the second metal body 3 is covered with an insulating material to prevent discharge from occurring in unintended areas. 【0054】 Furthermore, although the first metal body 2 is positioned above and the second metal body 3 is positioned below in the above description, the present invention is not limited to this. The first metal body 2 may be positioned below and the second metal body 3 above. In this case, the ball screw 52 of the feed device 5 may be attached to the second metal body 3. In this case, it is preferable that the other end of the second metal body 3 is connected to the GND terminal, which is the reference potential of the high-frequency supply device 4, in order to prevent electric shock. 【0055】 Furthermore, while the temperature detection unit 6 is described above as detecting temperature based on light generated at one end 2A of the first metal body 2 and one end 3A of the second metal body 3, the present invention is not limited thereto. For example, if the metal used as the raw material for metal nanoparticles has a low boiling point, the temperatures of one end 2A of the first metal body 2 and one end 3A of the second metal body 3 may be measured directly. 【0056】 Furthermore, although the above assumes that the flow regulator 81 is equipped with a stop valve 811, the present invention is not limited to this. The flow regulator 81 does not need to be equipped with a stop valve 811. However, it is more convenient to use the flow regulator 81 when recovering the liquid L in the container 1 if it is equipped with a stop valve 811. 【0057】 Furthermore, while the liquid replenishment unit 8 is configured to replenish liquid L in the container 1 by the depressurization device 7 reducing the pressure inside the container 1, the present invention is not limited to this. For example, the liquid replenishment unit 8 may be configured to replenish liquid L in the container 1 by a pump (not shown). 【0058】 Furthermore, while the control unit 91 controls the feed rate of the feeder 5 based on the temperature detected by the temperature detection unit 6 as described above, it is not necessary to always control the feed rate of the feeder 5 based on the temperature detected by the temperature detection unit 6 during the production of metal nanoparticles. For example, as the production of metal nanoparticles progresses, the liquid in the container 1 changes to a dark purple color. In this case, the temperature detection unit 6 may not be able to detect the light generated at one end 2A of the first metal body 2 and one end 3A of the second metal body 3. On the other hand, as the production of metal nanoparticles progresses (for example, a few minutes after plasma is generated), the distance between one end 2A of the first metal body 2 and one end 3A of the second metal body 3 may change steadily. In this case, the distance between one end 2A of the first metal body 2 and one end 3A of the second metal body 3 can be maintained by keeping the feed rate of the feeder 5 constant. That is, the control unit 91 may control the feed rate of the feeder 5 based on the temperature detected by the temperature detection unit 6 in the initial stages of metal nanoparticle production, while controlling the feed rate of the feeder 5 to maintain it at a specific speed after the initial stages of metal nanoparticle production. 【0059】 (Examples) A specific example of the metal nanoparticle manufacturing apparatus according to this embodiment will be described. 【0060】 In this embodiment, a T857-2 (13.56MHz) manufactured by Create Design Co., Ltd. was used as the high-frequency power supply 41, and a 102Y-X manufactured by Create Design Co., Ltd. was used as the regulator 42. The actuators used were DR28G2.5B03-AZAKU manufactured by Oriental Motor Co., Ltd. as the stepping motor 51 and ball screw 52. The motor driver 92 was an AZD-KD manufactured by Oriental Motor Co., Ltd. A DTU-20 manufactured by ULVAC KIKO Co., Ltd. was used as the vacuum pump 71, and an NVC-3000 manufactured by Tokyo Rikakikai Co., Ltd. was used as the pressure regulator 72. A BVC01-6 manufactured by Nippon Pisco Co., Ltd. was used as the stop valve 811, and an FMNV2-LB-2-V-N1 manufactured by IBS Co., Ltd. was used as the needle valve 812. 【0061】 Furthermore, a gold (Au) rod with a diameter of 3 mm was used as the first metal body 2 and the second metal body 3. The first metal body 2 was made of tin-plated copper flat braided wire (38 mm 2 The second metal body 3 was connected to the GND terminal of the high-frequency supply device 4 by ). 2 It was connected to the high-frequency output terminal of the high-frequency supply device 4 by a wire. The first metal body 2 and the second metal body 3 were positioned perpendicular to the liquid surface L in the container 1. The outer surfaces of the first metal body 2 and the second metal body 3 were covered with insulating tubes with an outer diameter of 6 mm and an inner diameter of 4 mm, respectively. 500 ml of water was placed in the container 1 as liquid L. 【0062】 After reducing the pressure in container 1 to 250 hPa (absolute pressure) using the depressurization device 7, a high-frequency power of 100 W to 150 W was applied to the first metal body 2 by the high-frequency supply device 4, generating plasma between one end 2A of the first metal body 2 and one end 3A of the second metal body 3. During the initial stages of gold (Au) nanoparticle production, the control unit 91 controlled the feed speed of the feed device 5 based on the temperature detected by the temperature detection unit 6. After the initial stages of gold nanoparticle production, the control unit 91 controlled the feed device 5 to achieve a feed speed of 2.5 μm / min by providing a 6-second pause time for every 0.25 μm movement per step. During the production of gold nanoparticles, water was replenished from the liquid replenishment unit 8 as needed. In this manner, the production of gold nanoparticles was carried out continuously for 6 hours. As the production of gold nanoparticles progressed, the water in container 1 changed to a dark purple color. The amount of water replenished into container 1 from the liquid replenishment container 82 was 200 ml. During the production of gold nanoparticles (6 hours), the plasma was generated continuously and stably. TEM imaging of the obtained particles (see Figures 4A and 4B) confirmed that they were gold nanoparticles with the desired particle size of approximately 10 nm in diameter. 【0063】 Figure 5 is a graph showing the relationship between the scale reading of the needle valve 812 and the water supply amount (amount of water added to container 1) when the pressure inside container 1 is 250 hPa. In the graph of Figure 5, the dotted line shows the amount of water evaporated from container 1 (approximately 1.1 mL / min) as confirmed in previous experiments. From Figure 5, it can be seen that the required amount of water can be added to container 1 by adjusting the scale reading of the needle valve 812 (setting the scale reading to 10). [Industrial applicability] 【0064】 The metal nanoparticle manufacturing apparatus according to the present invention can continuously manufacture metal nanoparticles of a desired particle size for a longer period of time, and is therefore particularly useful as an apparatus for manufacturing metal nanoparticles from metals having high boiling points. [Explanation of symbols] 【0065】 1 container 2 First metal body 2A One end 3 Second metal body 3A One end 4. High-frequency supply device 41 High frequency power supply 42 Coordination combiner 5. Feed device 51 Stepping motor 52 Ball screw 6. Temperature detection unit 61 Daylighting device 611 Light guide rod 612 Optical Fiber 62 Spectrometer 7. Pressure Reducing Device 71 Vacuum pump 72 Pressure Regulator 8 Fluid replenishment section 81 Flow regulator 811 Stop Valve 812 Needle Valve 82 Liquid refill container 9. Control Unit 91 PC 92 Motor Driver L liquid T thermometer

Claims

[Claim 1] A container for holding liquid, One end of the first metal body is placed inside the container and is made of a metal that serves as a raw material for metal nanoparticles. A second metal body is placed inside the container such that one end of the first metal body faces the other end of the first metal body, A high-frequency supply device that supplies high frequency to the liquid via one end of the first metal body or one end of the second metal body, and generates plasma between one end of the first metal body and one end of the second metal body, A feeding device that feeds the first metal body or the second metal body so that one end of the first metal body and one end of the second metal body are brought close together, A temperature detection unit for detecting the temperature of one end of the first metal body and one end of the second metal body, A control unit that controls the feed rate of the feed device based on the temperature detected by the temperature detection unit, A metal nanoparticle manufacturing apparatus equipped with the following features. [Claim 2] The metal nanoparticle manufacturing apparatus according to claim 1, wherein the temperature detection unit detects the temperature based on light generated at one end of the first metal body and one end of the second metal body. [Claim 3] The temperature detection unit is A light-collecting device that acquires light generated at one end of the first metal body and one end of the second metal body, A spectroscopic measuring device that spectrally measures the light acquired by the aforementioned light-collecting device, The metal nanoparticle manufacturing apparatus according to claim 2, comprising: [Claim 4] The metal nanoparticle manufacturing apparatus according to claim 1, further comprising a vacuum device for reducing the pressure inside the container. [Claim 5] The container further comprises a liquid refilling section for refilling the liquid inside the container. The metal nanoparticle manufacturing apparatus according to claim 4, wherein the liquid replenishment unit is configured to replenish the liquid in the container by the vacuum device reducing the pressure inside the container. [Claim 6] The metal nanoparticle manufacturing apparatus according to claim 5, wherein the liquid replenishment unit is equipped with a flow regulator capable of adjusting the flow rate of the liquid supplied into the container. [Claim 7] The aforementioned feeding device is A ball screw attached to the first metal body or the second metal body, A stepping motor that rotates the aforementioned ball screw around its axis, The metal nanoparticle manufacturing apparatus according to claim 1, comprising: [Claim 8] The metal nanoparticle manufacturing apparatus according to claim 7, wherein the control unit intermittently drives the stepping motor when the temperature detected by the temperature detection unit is near the boiling point of the first metal body to feed out the first metal body or the second metal body at a feed rate of 1 μm / min or more and 15 μm / min or less. [Claim 9] The metal nanoparticle manufacturing apparatus according to any one of claims 1 to 8, wherein the second metal body is composed of a metal that serves as a raw material for metal nanoparticles.

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