JP2007231317A - Fine particle collection container and fine particle collection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fine particle collection container capable of enhancing the yield of ceramic fine particles by collecting the ceramic fine particles which are scattered without being served for depositing a ceramic film in an aerosol deposition method, and a fine particle collection method using the container. <P>SOLUTION: The fine particle collection container 2 collects fine particles which are scattered without being served for deposition of a ceramic film in a vacuum chamber 5 in the aerosol deposition method for depositing the ceramic film on a base material 4 in the vacuum chamber 5. The fine particle collection container 2 comprises a filter having very fine holes, and is arranged so as to cover at least an ejection nozzle 8 and the base material 4, and provided with a mechanism (an oscillating device) 3 for removing the fine particles adhering on an inner wall of the collection container 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a collection container for ultrafine particles which are scattered without being formed in a ceramic film in an aerosol deposition method (hereinafter referred to as AD method), and a fine particle collection method using the container.

  For the purpose of forming a dense protective film on the surface of a substrate to express the physical and chemical properties such as the mechanical strength inherent to the substrate and to compensate for the physical and chemical properties that are inferior in corrosion resistance, etc. As an effective means, conventionally, a method of forming a sprayed coating such as ceramics on the surface of a substrate is known. However, the method of providing a ceramic layer on the substrate surface using thermal spraying technology is to form a ceramic layer while cooling the workpiece to prevent tempering due to heat during thermal spraying of the base material cured by heat treatment. It had to be done, was very complicated, and caused a decrease in productivity. Furthermore, if a ceramic layer is to be provided on the surface of the substrate by a thermal spraying method, it is necessary to spray a layer of nickel aluminum or the like in advance as a base treatment, which also causes a decrease in productivity.

  In addition, since the ceramic layer obtained by the thermal spraying method is porous, it is necessary to take measures against a decrease in physical properties such as insulation resistance due to intrusion of moisture due to condensation or the like by sealing treatment. For the sealing treatment, a method using a sealing resin containing at least one selected from the group consisting of a synthetic resin, a polymerizable organic solvent, and a fluorosurfactant and a perfluoro group-containing organosilicon compound (Patent Document 1). And a method of sealing by forming a combination layer having a sealing treatment layer made of a resin having good permeability as a lower layer and a sealing treatment layer made of an insulating resin having poor permeability as an upper layer (see Patent Document 2) ) Etc. are known. However, when these sealing methods are used, there is a problem that the cost becomes very high.

  In contrast, an aerosol in which raw material ceramic fine particles are dispersed in a gas is sprayed from an aerosol injection nozzle toward a base material, and the aerosol collides with the surface of the base material at a high speed, thereby forming a coating film made of a constituent material of ultrafine particles. An AD method for forming on a material is known. As an example of the AD method, an ultrafine particle molded body, which is a brittle material containing a fine crystal having a crystal size of 100 nm or less at 95% or more of the theoretical density by bonding an ultrafine particle brittle material of 50 nm to 5 μm on a substrate There is a low-temperature molding method of the obtained brittle material ultrafine particle compact (see Patent Document 3). With the AD method, a dense film of several μm to several tens of μm can be formed with good adhesion, and it is manufactured compared to the thermal spraying method because it does not require cooling of the workpiece, does not require base treatment such as nickel aluminum, and does not require sealing treatment. There is an advantage that the cost is significantly reduced.

However, in the AD method, the ultrafine particles that are formed into a ceramic film are 1 wt% to 10 wt% of the ceramic fine particles sprayed on the substrate, and there is a problem that the yield is extremely low. In addition, since the inside of the film forming apparatus is always in a vacuum environment, among the ceramic fine particles sprayed on the substrate, the ultra fine particles that are scattered without being formed into the ceramic coating are placed in front of the vacuum pump. However, clogging becomes a problem. When clogging occurs, there is a possibility that the degree of vacuum necessary for film formation may not be maintained, which is not preferable.
There is a method to increase the surface area of the filter to solve the problem of clogging and inability to form a film, but it is necessary to enlarge the vacuum chamber, and the enlargement of the equipment is inevitable. Then clogging is inevitable.
Japanese Patent No. 3009516 Japanese Patent Laid-Open No. 2003-183806 Japanese Patent No. 3265481

  The present invention has been made to cope with such a problem, and a fine particle collection container capable of collecting ceramic fine particles that are scattered without being subjected to formation of a ceramic coating in the AD method, and can improve the yield of the fine ceramic fine particles. An object of the present invention is to provide a fine particle recovery method using this container.

  The fine particle collection container of the present invention includes a ceramic coating film in an aerosol deposition method in which an aerosol in which ceramic fine particles are dispersed in a gas is sprayed onto a substrate from an aerosol spray nozzle in a vacuum chamber. A fine particle collection container used for collecting the ceramic fine particles scattered without being formed, wherein the fine particle collection container comprises a filter having fine pores through which the ceramic fine particles do not pass, and at least the above-mentioned It is arranged in the vacuum chamber so as to cover the aerosol spray nozzle and the substrate.

The fine particle collection container includes a mechanism for removing the ceramic fine particles adhering to the inner wall of the collection container from the inner wall.
In addition, the fine particle collection container includes a mechanism for storing the ceramic fine particles removed from the inner wall.

  The ceramic fine particles are alumina fine particles having an average particle diameter of 0.01 μm to 2 μm. In the present invention, the average particle diameter is a value measured by Nikkiso Co., Ltd .: Laser type particle size analyzer Microtrac MT3000.

  The fine particle recovery method of the present invention includes a ceramic coating in a film forming process by an aerosol deposition method in which an aerosol in which ceramic fine particles are dispersed in a gas is sprayed onto a substrate from an aerosol spray nozzle in a vacuum chamber. A method of collecting ultrafine particles by using a fine particle collection container disposed in a vacuum chamber, wherein the fine ceramic particles that are scattered without being formed are used in the method. It is a collection container.

The fine particle collection container of the present invention is provided with a filter having fine holes through which ceramic fine particles do not pass, and is disposed in a vacuum chamber so as to cover at least the aerosol injection nozzle and the substrate in the film formation process by the AD method. Therefore, among the ceramic fine particles sprayed on the base material, the ceramic fine particles scattered without being subjected to the formation of the ceramic coating can be captured on the inner wall of the fine particle collecting container.
Further, since the ceramic fine particles trapped on the inner wall of the collection container are equipped with a mechanism for removing the fine particles by, for example, removing the fine particles, the fine particles do not adhere to the inner wall of the collection container and become clogged and maintain a predetermined degree of vacuum. Can be a continuous aerosol injection. Further, since a mechanism such as a saucer for storing the removed fine particles is provided, the fine particle collection container can be taken out and the fine particles can be easily collected from the saucer or the like after the film forming operation is completed.

  Since the fine particle collection method of the present invention is a fine particle collection method using the fine particle collection container described above, the ceramic fine particles scattered without being subjected to the formation of the ceramic film in the film formation process by the AD method are subjected to a degree of vacuum due to clogging. It is possible to capture without lowering, and to collect at the end of the work. The collected ceramic fine particles can be used again as an aerosol raw material, and the yield of the ceramic fine particles can be improved.

In the AD method, an aerosol in which raw material ceramic fine particles are dispersed in a gas such as an inert gas is sprayed from an aerosol spray nozzle toward a base material, and the aerosol is made to collide with the surface of the base material at a high speed, thereby forming a constituent material of ultrafine particles. Is a method of forming a coating comprising: The ceramic fine particles are pulverized by collision to form a clean new surface and cause low-temperature bonding, so that bonding between ultra-fine particles can be realized at room temperature.
In the aerosol, the ceramic fine particles are maintained in a dispersed state. The coating obtained by the thermal spraying method is porous, whereas the coating obtained by the AD method forms the coating from the ultrafine particles dispersed in the aerosol as described above, so that the coating obtained is an extremely dense ceramic layer. Become. For this reason, even if the base material is exposed to moisture due to rainfall or condensation, the physical and chemical properties of the base material may be deteriorated because it is protected by a ceramic layer that does not have pores that allow moisture to penetrate. Absent.
Further, since the ceramic coating by the AD method is dense and extremely stable, the film thickness necessary for ensuring a certain strength and physical properties can be made thinner than that by the thermal spraying method.

Examples of the ceramic fine particles used as an aerosol raw material for forming a ceramic coating by the AD method in order to improve insulation performance and corrosion resistance include oxide ceramic fine particles such as alumina, zirconia, and titania. In the high-purity grade of each ceramic, alumina particles are preferred because the one with a lower true specific gravity is more easily aerosolized.
The average particle diameter of alumina fine particles that can be used in the AD method is 0.01 μm to 2 μm. If it is less than 0.01 μm, it is easy to agglomerate and it is difficult to form an aerosol. The particle size adjustment method of alumina fine particles includes alkoxide method and colloid method, pyrolysis method of ammonium alum, ammonium aluminum carbonate pyrolysis method, improved buyer method, chemical method of ethylene chlorohydrin method, gas evaporation method Heating fine ultrafine particles of several tens of nm or less, produced using physical techniques such as sputtering, vapor phase oxidation, and aluminum underwater spark discharge, secondary particles with a particle size of several hundreds of nanometers are heated. And the like.

The particulate collection container of the present invention will be described with reference to FIG. FIG. 1 is a view showing a ceramic film forming apparatus by AD method equipped with a fine particle collecting container of the present invention. FIG. 1 shows an example in which a film-forming base material is used as an outer ring of a bearing, and a ceramic film is formed on the outer peripheral surface of the outer ring.
As shown in FIG. 1, a ceramic film forming apparatus 1 using an AD method has a vacuum chamber 5. In the vacuum chamber 5, an outer ring as a base material 4 on which a ceramic film is to be formed is rotated (A in the figure) and an object rotating motor 7 is moved in the axial direction (B in the figure) for positioning XY. A table 6, an aerosol injection nozzle 8 for injecting aerosol, and a particulate collection container 2 covering all of them are disposed. Here, as shown in FIG. 1, when the outer ring or the like is used as the base material 4, the positioning XY table 6 and the object rotating motor 7 are used together. Only the XY table 6 may be used. Further, the substrate 4 may be fixed and the aerosol injection nozzle 8 may be moved.
The fine particle collection container 2 is composed of a filter having fine holes through which ceramic fine particles such as the above-mentioned alumina fine particles (average particle size: 0.01 μm to 2 μm) do not pass, and a method for removing fine particles adhering to the inner wall of the collection container 2 As an example, FIG. 1 includes a vibration device 3 that vibrates the collection container 2 itself.
The aerosol spray nozzle 8 sprays ceramic fine particles onto the surface of the substrate 4 from the tip of a nozzle having an opening such as a rectangle.
The inside of the vacuum chamber 5 is depressurized by the vacuum pump 10. In order to prevent mixing of ceramic fine particles, a fine particle filter 9 is provided immediately before the vacuum pump 10.
As an aerosol carrier gas, an inert gas is used and is supplied from the gas supply facility 12 to the aerosol generator 11. Usable inert gases include argon, nitrogen, helium and the like.

The fine particle collection container of the present invention may be constituted by a filter having fine holes through which ceramic fine particles do not pass so that ceramic fine particles scattered without being applied to the ceramic coating can be captured.
As a filter material, any of woven fabric, non-woven fabric, resin porous body and the like can be used without particular limitation. Among these, it is preferable to use an inexpensive non-woven fabric. In addition, as resin which comprises a filter, both a thermoplastic resin and a thermosetting resin can be used without a restriction | limiting in particular.
The fine particle collection container of the present invention is required to be disposed in a vacuum chamber so as to cover at least the aerosol injection nozzle and the substrate. In addition, by reducing the number of sealing points with the movable part in the vacuum chamber, the object rotating motor for rotating the base material, the positioning XY table, etc. in order to efficiently capture the ceramic particles scattered in the particle collecting container, etc. It is preferable to be disposed in a covering form.
The particulate collection container may have an indefinite shape such as a bag, in addition to a predetermined shape such as a box, as long as the above requirements are satisfied.

In the AD method, the ratio of the ceramic fine particles that are scattered without being formed to the ceramic coating to the amount of the ceramic fine particles injected reaches 90% to 99% by weight, resulting in clogging and maintaining the degree of vacuum. In consideration of difficulty, it is preferable that the fine particle collection container of the present invention includes a mechanism for removing fine particles attached to the inner wall of the collection container.
As a mechanism for removing ceramic fine particles adhering to the inner wall of the collection container, a mechanism for removing the fine particles by washing the inner wall to which the fine particles have adhered (brushing, air shower, etc.), or applying vibration to the inner wall to which the fine particles have adhered. And a mechanism for removing fine particles from the inner wall.
Among these, it is preferable to adopt a mechanism that applies vibrations to the inner wall and removes ceramic fine particles from the inner wall because it is easy to install and operate. Specifically, a method of attaching a vibration motor, a striking device or the like to the outer wall of the collection container and applying vibration to remove the ceramic fine particles is preferable.
Further, it is preferable to install a tray on the bottom of the container body in order to easily store the collected ceramic fine particles and to facilitate collection. As the shape of the saucer, a cone-like saucer or the like having a sharp edge with respect to the bottom surface on which the fine ceramic particles are easily collected is preferable.

The fine particle recovery method of the present invention will be described with reference to FIG. As shown in FIG. 1, an aerosol using ceramic fine particles as a raw material is supplied from an aerosol generator 11, and an outer ring (base material 4) rotated at a predetermined rotational speed by an object rotating motor 7 from an aerosol injection nozzle 8. Then, aerosol is sprayed, and a ceramic film is formed on the outer ring (base material 4). At the same time, the outer ring (base material 4) is moved in the axial direction by the positioning XY table 6, so that a film is uniformly formed on the surface of the outer ring (base material 4). All of these operations are performed in a space covered with the particulate collection container 2. Note that an inert gas is used as the carrier gas for the aerosol and is supplied from the gas supply facility 12 to the aerosol generator 11.
Gas injected onto the outer ring (base material 4) and ceramic fine particles that have not been used for forming the ceramic film are sucked by the vacuum pump 10 through the vacuum chamber 5, and the ceramic fine particles that have not been used for forming the ceramic film are filtered. It adheres to the inner wall of the fine particle collection container 2 made of Ceramic fine particles adhering to the inner wall are wiped off by the vibration device 3 and fall to the bottom of the fine particle collecting container 2, and clogging of the ceramic fine particles on the inner wall is prevented.
After completion of the operation for forming the ceramic film, the fine particle collection container 2 is taken out of the vacuum chamber 5 and the ceramic fine particles stored in the bottom of the container are collected.

Example Using the ceramic film forming apparatus 1 equipped with the particulate collection container 2 and the vibration device 3 shown in FIG. 1, 100 grams of alumina particulate was charged into the aerosol generating device 11 and the outer ring (6202: SUJ2, dimensions) as the base material 4 35 mm × 29 mm × 15 mm) was formed by the AD method. The AD method uses a driving device that uses a positioning XY table 6 and an object rotation motor 7 in combination with a base material 4 that moves in the axial direction while rotating at a peripheral speed of 6 mm / min. Under reduced pressure of 100 Pa or less, an aerosol of alumina fine particles was sprayed through a nozzle having an opening size of 5 mm × 0.3 mm to form a film. The film was formed until the film thickness reached 4 μm.
Alumina fine particles were manufactured by Daimei Chemical Industry Co., Ltd .: Tymicron TM-DAR, and used after heat-drying under reduced pressure of 10 Pa or less with an average particle size of 0.16 μm. Helium was used as the carrier gas, and the particle velocity was controlled by the carrier gas flow rate.
The film formation time was 30 minutes, and the inside of the vacuum chamber was kept stably at 1 kPa or less during the film formation operation.
Further, after the formation of the film, the fine particle collection container 2 and the fine particle filter 9 were taken out and observed. As a result, a large amount of alumina fine particles were deposited on the bottom of the fine particle collection container 2, and the alumina fine particles adhered to the fine particle filter 9. There wasn't.

Comparative Example A film was formed on the outer ring as the base material 4 in the same manner as in Example 1 except that the ceramic film forming apparatus 1 without the particulate collection container 2 and the vibration device 3 shown in FIG. 1 was used.
During the film formation operation, the reduced pressure of 100 Pa or less increased to 30 kPa or more 5 minutes after the start of injection, and it took 120 minutes to form the film.
After the film formation was completed, the fine particle filter 9 was taken out and observed, and as a result, alumina fine particles adhered and clogging occurred.

  The fine particle collection container of the present invention is composed of a filter having fine pores, and is disposed so as to cover at least the aerosol injection nozzle and the base material, so that the ceramic fine particles scattered without being formed by the ceramic coating can be efficiently collected. Therefore, it can be suitably used in a ceramic film forming apparatus using an AD method used in various industries.

It is a figure which shows the ceramic film formation apparatus by AD method equipped with the fine particle collection container of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ceramic film formation apparatus 2 Fine particle collection container 3 Vibrating device 4 Base material 5 Vacuum chamber 6 XY table for positioning 7 Object rotation motor 8 Aerosol injection nozzle 9 Fine particle filter 10 Vacuum pump 11 Aerosol generator 12 Gas supply equipment

Claims (5)

In the film deposition process using the aerosol deposition method in which aerosol is formed by spraying ceramic fine particles dispersed in a gas from a aerosol spray nozzle onto a substrate in a vacuum chamber, the ceramic film is not formed and scattered. A fine particle collection container used for collecting the ceramic fine particles,
The fine particle collection container includes a filter having fine holes through which the ceramic fine particles do not pass, and is disposed in the vacuum chamber so as to cover at least the aerosol injection nozzle and the base material. Collection container.   The fine particle collection container according to claim 1, further comprising a mechanism for removing the ceramic fine particles adhering to the inner wall of the collection container from the inner wall.   The fine particle collection container according to claim 1 or 2, wherein the fine particle collection container comprises a mechanism for storing ceramic fine particles removed from the inner wall.   4. The fine particle collection container according to claim 1, wherein the ceramic fine particles are alumina fine particles having an average particle diameter of 0.01 to 2 [mu] m. In the film deposition process using the aerosol deposition method in which aerosol is formed by spraying ceramic fine particles dispersed in a gas from a aerosol spray nozzle onto a substrate in a vacuum chamber, the ceramic film is not used for the formation and scatters. An ultrafine particle collection method for collecting the ceramic fine particles by a fine particle collection container disposed in a vacuum chamber,
The fine particle collection container according to any one of claims 1 to 4, wherein the fine particle collection container is the fine particle collection container.

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