JP2006219764A - Aerosol generator, apparatus for forming composite structure, and method of forming composite structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aerosol generator capable of supplying a stable aerosol and an apparatus for forming a composite structure equipped therewith, an aerosol generating method, and a method of forming the composite structure. <P>SOLUTION: In a powder supplying section 22, a rotary table 60 is arranged between a powder housing section 21 and an aerosolizing section 23 and powder is supplied from the powder housing section 21 into a rectangular groove 63 formed by a notched groove 61 formed at the circumferential edge of the rotary table 60 and a semi-annular guide 62 arranged along the outer peripheral side face of the notched groove 61. The powder supplied into the rectangular groove 63 is conveyed up to a plate 64 for cutting by rubbing as the rotary table 60 rotates. The conveyed powder in the groove 63 is cut by rubbing by the plate 64 for cutting by rubbing and is supplied to the aerosolizing section 23. The amount of the supply to the aerosolizing section 23 is controlled by adjusting the rotating speed of the rotary table 60 and changing the dimensions and shape of the width and depth of the groove 63. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aerosol generating device, an aerosol generating method for generating an aerosol by dispersing powder in a gas, a composite structure manufacturing device and a composite structure manufacturing method incorporating this aerosol generating device.

  In recent years, an aerosol generator that generates aerosol by dispersing powder in a gas has been used for a room temperature film forming technique of brittle material fine particles by an aerosol deposition method (Patent Document 1).

  In addition, as a powder supply device in a system for supplying powder into a plasma together with a carrier gas and depositing the powder on a prearranged sample, the powder is dropped from a powder container into a groove formed in a rotatable powder supply board. A device has been proposed. (Patent Document 2)

  In the aerosol deposition method, basically, an aerosol obtained by dispersing fine particles of brittle material having primary particles of about 0.1 to 5 μm in a gas is sprayed onto a substrate at a high speed of subsonic speed to obtain a film-formed body. Here, in order to perform uniform film formation, it is necessary that the brittle material fine particles in the aerosol be sprayed onto the substrate in a state where they are not aggregated as much as possible. For this purpose, as the aerosol generating device, a container for storing ceramic fine particles is installed in a casing, and a gas introduction pipe and an aerosol lead-out pipe are connected to the casing, and the ceramic fine particles in the container are formed by gas from the gas introduction pipe. An aerosol generating device has been proposed in which the aerosol is converted into an aerosol and the aerosol is taken out from the aerosol lead-out tube. (Patent Document 3)

  Furthermore, in order to generate aerosol stably, the ceramic fine particles are stored in a container to which the gas introduction pipe and the aerosol outlet pipe are connected, and the container is reciprocated (direction perpendicular to the gravity vector direction) or eccentrically rotated. Therefore, proposals have been made to aerosolize ceramic fine particles by gas destructive force and vibration. (Patent Document 4)

: JP 2001-181859 A : JP-A-5-239627 : JP-A-2001-348658 : JP 2003-166076 A

  The apparatus described above is not suitable for mass production. That is, for mass production, it is necessary to stably generate aerosol for a long time, but the conventional apparatus cannot generate aerosol continuously. Further, once the device is stopped and the fine particles are replenished, it becomes difficult to generate aerosol at a uniform concentration. Furthermore, powders with poor fluidity or easily agglomerate are likely to be clogged or bridging in the apparatus, and it is difficult to stabilize powder transport for a long time.

In particular, the apparatus disclosed in Patent Document 2 stirs powder with compressed gas, but does not use aerosol, and the operation must be interrupted when the powder in the stirring chamber runs out.
In Patent Document 3, if the ceramic fine particles contained in the container are used up, the aerosol gas deposition operation must be interrupted.
Further, in Patent Document 4, as in Patent Document 3, if the ceramic fine particles in the container are used up, the aerosol gas deposition operation must be interrupted.

  In addition, when the fine particles are metal oxides, they have strong cohesive adhesion and easily clog or bridging in the apparatus. In addition, when it comes into contact with the atmosphere, it absorbs moisture, and more easily clogs and bridges, and may not be able to be aerosolized.

  The present invention has been made in view of the above circumstances, and an aerosol generator capable of stably generating an aerosol at the same concentration as the initial state even when the aerosol is generated for a long time, the aerosol generator, and its It aims to provide a method.

In order to solve the above-mentioned problem, the first invention is to spray an aerosol in which fine particles of a brittle material having primary particles of 0.1 to 5 μm are dispersed in a gas toward a base material from a nozzle, and the aerosol is converted into the base. An aerosol generator for use in a composite structure manufacturing apparatus that collides with the surface of a material and forms a structure made of the constituent material of the fine particles on the base material, the aerosol generator being a powder container that contains fine particles And a powder supply unit for quantitatively supplying fine particles from the powder storage unit, and a gas inlet pipe and an aerosol outlet pipe, and the gas from the gas inlet pipe is connected directly to the gas inlet pipe. An aerosol generation unit for extracting fine particles from the aerosol extraction tube was used.
Further, in the second invention, an aerosol in which fine particles of a brittle material having primary particles of 0.1 to 5 μm are dispersed in a gas is jetted from a nozzle toward the substrate, and the aerosol collides with the substrate surface. An aerosol generator for use in a composite structure manufacturing apparatus for forming a structure composed of the constituent material of the fine particles on the base material, the aerosol generator including a powder container for storing fine particles, and the powder A powder supply unit which is a circulating transport means for transporting fine particles from the body containing unit, and a gas inlet pipe and an aerosol outlet pipe are directly connected to each other, and gas from the gas inlet pipe is supplied from the powder supply unit. And an aerosol-generating unit that derives the fine particles from the aerosol lead-out tube.

In the present invention, aerosol refers to a solid-gas mixed phase in which fine particles are dispersed in a gas. In the aerosol used in the aerosol deposition method, fine particles are preferably dispersed in the form of primary particles, but may also contain aggregated particles.

In a preferred aspect of the aerosol generator of the present invention, the powder supply unit, the powder storage unit, and the aerosol generation unit are stored in a vacuum system.
As a first reason for accommodating in the vacuum system, the structure forming chamber for performing the aerosol deposition needs to be maintained in a vacuum in order to prevent the fine particles from being oxidized or reacted. If the aerosol generating unit connected to the structure forming chamber, or the powder supply unit and the powder storage unit communicating with the aerosol forming unit are kept at atmospheric pressure, it is difficult to maintain the vacuum state of the structure forming chamber. . Therefore, the aerosolization unit, the powder supply unit, and the powder storage unit are housed in a vacuum system, and the aerosolization unit, the powder supply unit, and the Arrange the powder container. As a second reason, it is necessary to use a high-purity gas in the structure formation process by aerosol deposition. It has been elucidated that the conveying speed of the powder differs depending on the type of gas and greatly affects the characteristics of the structure. Therefore, it is necessary to use a high-purity gas and constantly stabilize the powder conveyance speed. In addition, when air is mixed in, problems such as contamination entering the structure may occur, and it is necessary to prevent them.
In order to replenish fine particles (powder) without interrupting the operation of the powder storage unit arranged in such a vacuum system, a load lock chamber is provided.

In addition, a composite structure manufacturing apparatus according to the present invention includes the above-described aerosol generation apparatus and a nozzle for spraying the aerosol onto the base material.
Also, the aerosol generating method according to the present invention feeds fine particles from a powder container capable of replenishing fine particles to a powder supply unit, and a predetermined amount of powder is continuously supplied to the aerosol generation unit by the powder supply unit. Then, an aerosol in which fine particles are dispersed in the gas is generated in the aerosol generation unit.
Further, in the composite structure manufacturing method according to the present invention, the aerosol generated by the above-described aerosol generation method is supplied to the nozzle of the composite structure manufacturing apparatus, and the aerosol is made to collide with the substrate surface from the nozzle. The fine particles are crushed and deformed and joined to form a structure made of the constituent material of the fine particles on the substrate.

By using the aerosol generator according to the present invention, it is possible to generate aerosol at the same concentration as the initial state for a long time.
Further, since the apparatus can be performed without stopping the apparatus when replenishing powder (fine particles), the aerosol can be supplied to the nozzle in a stable state without changing the conditions for generating the aerosol.

  The aerosol deposition method considered as one of the places of use of the device according to the claim is a method in which an aerosol in which fine particles such as brittle materials are dispersed in a gas is sprayed from a nozzle toward a base material, and metal, glass, ceramics Particles collide with a substrate such as plastic or plastic, and the impact of this collision causes the particles of brittle material to be deformed or crushed and joined together to directly form a structure composed of the constituent material of the particles on the substrate. In particular, a structure can be formed at room temperature that does not require a heating means, and a structure having mechanical strength equivalent to that of a fired body can be obtained. The apparatus used in this method basically consists of an aerosol generator for generating aerosol and a nozzle for injecting the aerosol toward the base material. When a structure is produced with a larger area than the opening of the nozzle, In addition, it has a position control means that moves and swings the base material and the nozzle relative to each other, and has a chamber and a vacuum pump for forming a structure when producing under reduced pressure, and also generates aerosol It is common to have a gas source.

  The process temperature of the aerosol deposition method is room temperature, and one feature is that the structure is formed at a temperature sufficiently lower than the melting point of the particulate material, that is, several hundred degrees C. or less.

  In addition, the fine particles used are mainly brittle materials such as ceramics and semiconductors, and fine particles of the same material can be used alone or mixed, and different fine particles of brittle material can be mixed or used in combination. Is possible. Further, it is also possible to mix a part of a metal material or an organic material with brittle material fine particles or to coat the surface of brittle material fine particles. Even in these cases, the main component of structure formation is a brittle material.

  In the structure formed by this method, when crystalline brittle material fine particles are used as a raw material, the brittle material portion of the structure is a polycrystalline body whose crystallite size is smaller than that of the raw material fine particles, and the crystal In many cases, there is substantially no crystal orientation, and it can be said that there is substantially no grain boundary layer consisting of a glass layer at the interface between brittle material crystals, and a part of the structure is an anchor that bites into the substrate surface It is characterized by often forming a layer.

  The structure formed by this method clearly has a sufficient strength unlike a so-called green compact in which fine particles are packed by pressure and keeps a form by physical adhesion.

  In this structure formation, it can be judged that the brittle material fine particles are crushed and deformed by measuring the brittle material fine particles used as a raw material and the crystallite size X-ray diffraction of the formed brittle material structure. . That is, the crystallite size of the structure formed by the aerosol deposition method is smaller than the crystallite size of the raw material fine particles. A new surface in which atoms originally present inside and bonded to other atoms are exposed is formed on the slip surface or fracture surface formed by crushing or deforming fine particles. This active new surface having a high surface energy is considered to be formed by joining the surface of the adjacent brittle material, the new surface of the adjacent brittle material, or the substrate surface. In addition, when hydroxyl groups are present on the surface of the fine particles moderately, a mechanochemical acid-base dehydration reaction occurs due to local shear stress generated between the fine particles and between the fine particles and the structure when the fine particles collide with each other. It can be considered. The addition of continuous mechanical impact force from the outside causes these phenomena to occur continuously, and the progress and densification of joints are performed by repeated deformation and crushing of fine particles, and brittle material structures grow. it is conceivable that.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an apparatus diagram of a composite structure manufacturing apparatus incorporating an aerosol generating apparatus according to the present invention. The composite structure manufacturing apparatus includes a structure forming chamber 10 for performing aerosol deposition, and a structure forming chamber 10. The structure forming chamber 10 is maintained at a high vacuum by a pump 11 and includes a nozzle 12 having a rectangular opening for ejecting aerosol into the structure forming chamber 10 and a computer. A substrate holder 13 that can be braked vertically (Z), front and rear, left and right (XY), and a base material 14 attached to the substrate holder 13 are arranged, and a signal from a sensor 15 that measures the concentration of aerosol to the nozzle 12 is received. It is sent to an external feedback control circuit 16 for processing, and the aerosol generator 20 and the gas cylinder 30 filled with nitrogen gas for transportation are used. A signal is sent via the line 17 to the control unit of the respectively performs control so that any amount of supply amount of aerosol that impinges on the substrate to control the aerosol concentration.

  On the other hand, as shown in FIG. 2, the aerosol generator 20 includes a powder container 21 capable of replenishing fine particles such as ceramics and metal oxides, and a powder for quantitatively supplying fine particles from the powder container 21. A body supply unit 22 and an aerosolization unit 23 that aerosolizes the fine particles supplied from the powder supply unit 22 are provided. A gas introduction pipe 24 and an aerosol lead-out pipe 25 are connected to the aerosol generating unit 23.

  The powder supply unit 22 may be provided with a mechanism for controlling the supply amount of fine particles. As this mechanism, as shown in FIG. 3A, a slide plate 27 is slidably overlapped with a bottom plate of a powder supply unit 22 in which an opening 26 of a flow path is formed, and an opening 28 and an opening formed in the slide plate 27 are formed. A structure is conceivable in which the flow path is narrowed at a portion in common with 26. Further, as shown in FIG. 3 (b), a configuration is conceivable in which a conical valve 29 is disposed in the opening 26 of the flow path so as to be movable up and down.

FIG. 4 is a cross-sectional view of the powder container 21, and the powder container 21 is decompressed as described above. Therefore, a load lock chamber 40 is attached. The load lock chamber 40 and the powder container 21 are partitioned by a gate 41.
In order to supply the powder (fine particles) into the powder container 21, the lid 42 of the load lock chamber 40 is opened with the gate 41 closed, and the powder (fine particles) is filled therein, and the lid After closing 42, the inside of the load lock chamber 40 is depressurized through the suction pipe 43 until the pressure is almost the same as that in the powder storage unit 21. Supply powder (fine particles). At this time, when the gate 41 is suddenly opened, a large amount of powder (fine particles) is supplied into the powder containing portion 21 in a short time, and the powder (fine particles) at the bottom of the powder containing portion 21 is compacted. Will change. In order to prevent this, a driving device that automatically controls the opening and closing of the gate 41 is attached, and the amount of powder (fine particles) supplied to the powder container 21 is adjusted to a very small amount by opening at low speed.

The powder supply unit 22 may have a structure shown in FIGS. 5 to 9 in order to adjust the amount of fine particles supplied to the aerosol-generating unit 23.
The powder supply unit 22 shown in FIG. 5 has an endless belt 50 disposed between the powder storage unit 21 and the aerosol generating unit 23, and the powder from the powder storage unit 21 is placed in a groove 51 formed in the endless belt 50. The endless belt 50 travels to supply a predetermined amount of powder to the aerosol generating unit 23. Note that the supply amount to the aerosol generating unit 23 is controlled by adjusting the traveling speed of the endless belt 50 or changing the width and depth of the groove 51 and the shape thereof.

  Further, the powder supply unit 22 shown in FIG. 6 has a rotary table 60 disposed between the powder storage unit 21 and the aerosol-generating unit 23, and a notch groove 61 formed on the peripheral edge of the rotary table 60, Powder is supplied from the powder storage unit 21 into a rectangular groove 63 formed by a semi-annular guide 62 disposed along the outer peripheral side surface of the notch groove 61. The powder supplied to the rectangular groove 63 is conveyed to the scraping plate 64 as the rotary table 60 rotates. The transported powder in the groove 63 is scraped off by the scraping plate 64 and supplied to the aerosol generating unit 23. Note that the supply amount to the aerosol generating unit 23 is controlled by adjusting the rotation speed of the rotary table 60 or changing the width and depth dimensions and shape of the groove 63.

  The powder supply unit 22 shown in FIG. 7 has a rotary table 80 provided with a certain gap between the powder storage unit 21 and the aerosolization unit 23, and the powder stored in the powder storage unit 21. However, the rotary table 80 rotates and passes through the gap between the split body accommodating portion 21 and the rotary table 80, and is supplied in a state where the rotary table 80 is uniformly spread over the rotary table 80. The powder spread on the rotary table by the rotation of the rotary table 80 is conveyed to the aerosolization unit 23. The aerosol generating unit 23 maintains a certain gap with the rotary table, and the powder passes through this gap and is conveyed into the aerosol generating unit.

  Next, the inside of the aerosol-generating part is shown in FIG. The powder 82 that has passed through the gap between the aerosolization part and the rotary table and is introduced into the aerosolization part is diffused and crushed by the gas ejected from the gas introduction pipe 24 to be aerosolized. Further, the scraping mechanism 81 can be provided between the gas introduction pipe 24 and the aerosol introduction pipe. As a result, it is possible to reliably scrape out the powder that is fixed and agglomerated and is not aerosolized, thereby increasing the efficiency of aerosolization. The amount supplied to the aerosol generating unit 23 is controlled by adjusting the rotational speed of the rotary table 80 or changing the gap interval between the powder container 21 and the rotary table 80. Further, the concentration of the aerosol generator can be controlled by changing the size and shape of the scraping mechanism 81.

In the powder supply unit 22 shown in FIG. 9, a rotary table is disposed between the powder storage unit 91 and the aerosolization unit 94 as a circulating transport unit 92.
For the powder in the powder container 91, the powder is put into the groove 93 on the rotary table 92 by using the weight of the powder, a stirring member, or applying vibration to the powder container 91. Supply.
Specifically, an annular groove 93 is formed on the horizontal upper surface of the rotary table 92, the powder is supplied into the powder container 91, and then the powder overflowed upward from the groove 93 by a squeegee plate or the like. In this state, the powder in the groove 93 is sent to the aerosolization means 94 by the rotation of the rotary table 92, and is supplied to the nozzle as aerosol.
It is possible to adjust the amount of powder transport by changing the size of the groove 93 or changing the rotational speed by the driving means.

Overall configuration diagram of a composite structure manufacturing apparatus incorporating an aerosol generating apparatus according to the present invention The figure which shows arrangement | positioning of each part which comprises the same aerosol generator. (A) And (b) is a figure which shows another example of a powder supply part. Diagram showing the structure of the load lock chamber Perspective view showing a specific example of the powder supply unit Perspective view showing a specific example of the powder supply unit Perspective view showing a specific example of the powder supply unit 7 is an enlarged cross-sectional view of the main part of FIG. Perspective view showing a specific example of the powder supply unit

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Structure formation chamber, 11 ... Pump, 12 ... Nozzle, 13 ... Substrate holder, 14 ... Base material, 15 ... Sensor, 16 ... Feedback control circuit, 17 ... Wiring, 20 ... Aerosol generator, 21 ... Powder storage , 22 ... powder supply unit, 23 ... aerosolization unit, 24 ... gas introduction pipe, 25 ... aerosol outlet pipe, 26 ... channel opening, 27 ... slide plate, 28 ... opening, 29 ... conical valve , 40 ... Load lock chamber, 41 ... Gate, 42 ... Lid, 43 ... Suction pipe, 50 ... Endless belt, 51 ... Groove, 60 ... Rotary table, 61 ... Groove, 62 ... Scraping plate, 80 ... Rotary table, 81 ... Crushing mechanism, 82 ... powder, 91 ... powder storage unit, 92 ... rotary table, 93 ... groove, 94 ... aerosolization means.

Claims (4)

An aerosol in which fine particles of a brittle material having a primary particle of 0.1 to 5 μm are dispersed in a gas is jetted from a nozzle toward a base material, and the aerosol collides with the surface of the base material. An aerosol generator for use in a composite structure manufacturing apparatus for forming a structure on a substrate, wherein the aerosol generator quantifies fine particles from the powder container and fine particles from the powder container. Aerosolization that is directly connected to a powder supply unit to be supplied, a gas introduction pipe, and an aerosol lead-out pipe, and that uses the gas from the gas introduction pipe to derive fine particles from the powder supply part from the aerosol lead-out pipe And an aerosol generating device characterized by being capable of generating aerosol at the same concentration as the initial state for a long time. 2. The aerosol generating apparatus according to claim 1, wherein the powder supply unit, the powder storage unit, and the aerosol generating unit are arranged in a vacuum system. An apparatus for producing a composite structure comprising an aerosol generating device and a nozzle for causing aerosol to be sprayed onto the base material to collide with the surface of the base material to form a structure made of the constituent material of the fine particles on the base material. A composite structure manufacturing apparatus comprising the aerosol generating apparatus according to claim 1 or 2 as an aerosol generating apparatus. A composite structure manufacturing method using the composite structure manufacturing apparatus according to claim 3, wherein an aerosol in which fine particles are dispersed in a gas is generated in the aerosolization unit, and the aerosol is used for the composite structure manufacturing apparatus. A composite structure manufacturing method in which an aerosol is made to collide with a substrate surface from a nozzle, the fine particles are joined by impact of the collision, and a structure made of a constituent material of the fine particles is formed on the substrate.