JP5946179B2 - Ceramic film forming apparatus and method - Google Patents

Description

  The present invention relates to a ceramic film forming apparatus and a film forming method for continuously forming a film by refining ceramic raw material powder, performing processing such as crushing and classification, and supplying the fine powder.

  As a technique for forming a film using a powder of ceramics or metal, there are thermal spraying, a cold spray (CS) method, an aerosol deposition (AD) method, and a plasma-assisted AD method. The thermal spraying method, the CS method, and the plasma-assisted AD method are methods in which a film is formed by applying a temperature to a gas carrying a material or powder, and the AD method is a method in which a film is formed at room temperature.

  According to Patent Document 1 and Non-Patent Document 1, the refinement of powder by high-frequency plasma is called a thermal plasma method, which is generated by instantaneously bringing the powder into a thermal plasma to form a gas phase and rapidly solidifying it. This is a method for producing fine particles. In the AD method, water and impurities physically adsorbed on the powder adversely affect the film quality. Therefore, it is necessary to process the powder as disclosed in Patent Documents 2 and 3.

  In the plasma-assisted AD method, according to Non-Patent Document 2, the amount of film formation is improved as compared with the case where plasma is not used. Patent Document 4 describes a process of applying internal strain to brittle material fine particles. The brittle material fine particles given internal strain by this process are collided with the base material, the brittle material fine particles are crushed or deformed by this impact, thereby generating active surfaces, and the active surfaces are recombined to form a composite structure. Is formed.

  On the other hand, in the process of conveying the raw material powder, there is a problem that a large amount of the raw material powder adheres to the conveying tube. As a countermeasure, Patent Document 5 discloses a method for suppressing clogging caused by accumulation of fine particles on the wall surface of a transport pipe by applying an alternating electric field to an electrode attached in a double spiral to a tube-shaped transport pipe. Is described.

JP2007-029859 JP2008-088559 JP 2007-119913 A JP2002-20878 JP2010-241550 Masahiro Kagawa, “Manufacture of Fine Particle Materials by Thermal Plasma Process”, Aerosol Research, Vol. 10, No. 1 (1995), p. 20-27 Jun Meido, “Fundamentals and Applications of Aerosol Deposition Method”

  The process of activating the particle surface and applying internal strain to the powder particles are performed by batch processing. Therefore, for example, when a film is formed on a large base material using the AD method or when mass production is performed, a large cost is required in a manufacturing process that requires a large amount of raw material powder.

  On the other hand, in the AD method and the plasma-assisted AD method, the optimum particle size of the powder for film formation is 0.1 to 1 μm. In general, however, powders in this particle size range are more expensive than powders of the same material having a particle size of several tens of micrometers. Furthermore, in order to obtain a high-purity film, the raw material powder itself needs to have a high purity, and a high-purity powder having an optimum particle size becomes more expensive and costly.

  For example, in the AD method and the plasma-assisted AD method, when a powder having a particle size of 3 μm or more is used, the film is scraped and the film quality is deteriorated. Therefore, this size of powder is not suitable for the film forming method. If a powder having a particle size of 0.1 μm or less is used, a green compact that is pressed and compacted by a collision pressure is formed, so that the amount of film formation is reduced or no film is formed. Not suitable for the film formation method. As mentioned in the AD method and the plasma-assisted AD method, when particles outside the optimum particle size range are mixed in the raw material powder, the film quality of the film is reduced and the amount of film formation is reduced. Is necessary.

  Furthermore, the powder having a particle size of 0.1 to 1 μm adheres to the inner wall of the transfer tube during gas transfer, thereby reducing the amount of powder supplied and closing the transfer tube. The clogging of the powder in the transfer tube hinders stable supply of the raw material powder, and causes further deterioration of the film quality and a decrease in the film formation amount.

  In view of the above-described problems of the prior art, the present invention provides a ceramic film-forming apparatus capable of obtaining a high-quality film by reducing the cost and supplying a powder having an optimum particle size in a stable state. And a film forming method.

In order to achieve the above object, the following technical measures were taken.
That is, the ceramic film forming apparatus of the present invention includes a powder refining means for refining ceramic raw material powder to a predetermined particle diameter, and a transport for transporting the refined powder discharged from the powder refining means by air flow through a transport pipe. And a film forming means for injecting the fine powder conveyed from the powder refining means via the conveying means onto a film forming object, and forming the film. The ceramic raw material powder is configured to be refined by volatilizing the surface thereof by high-frequency plasma, or the ceramic raw material powder is converted to a gas phase state by high-frequency plasma and then cooled and precipitated to be refined. The conveying means is configured to prevent the powder from adhering to and clogging the inner wall of the conveying pipe by applying an AC electric field and an electrostatic field to the conveying pipe. Means comprises a plasma torch for heating the powder, characterized in that it has a nozzle for injecting a heated powder into the film-forming target attached to the torch.

  The powder refinement means of the ceramic film forming apparatus of the present invention is configured such that the ceramic raw material powder is refined by volatilizing the surface thereof by high frequency plasma, or the ceramic raw material powder is removed by high frequency plasma. It is configured to be fined by becoming a phase state and then cooled and precipitated, and the conveying means of the apparatus is configured to prevent powder adhesion and blockage to the inner wall of the conveying pipe, and the film forming means of the apparatus is It has a plasma torch for heating powder and a nozzle attached to the torch.

  Therefore, continuous processing is possible instead of batch processing, and costs can be significantly reduced even in manufacturing processes that require a large amount of raw material powder, such as when a film is formed on a large substrate or when mass production is performed. Furthermore, the powder refinement means can obtain a powder having the optimum particle size for film formation, and particles outside the optimum particle size range are not mixed into the raw material powder, so that the film quality of the film is reduced and the amount of film formation is reduced. It can be prevented from causing. Moreover, even if the raw material powder is highly miniaturized by the transport means, it does not adhere to the inner wall of the transport pipe during gas transport, and does not reduce the amount of powder supplied and does not block the transport pipe. Thereby, the cost can be suppressed, and the powder having the optimum particle size can be supplied in a stable state, and a high-quality film can be formed.

  It is preferable that the said powder refinement | miniaturization means is comprised so that the average particle diameter of ceramic raw material powder may be refined | miniaturized to 0.01-10 micrometers by high frequency plasma. In this case, it becomes a highly purified fine powder and quality can be improved.

  The frequency for forming the high-frequency plasma in the powder refinement means is preferably 10 kHz to 13.56 MHz, and the output of the plasma power source is preferably 5 to 100 kW. By selecting such conditions, the particle size of the ceramic raw material powder can be adjusted more optimally.

  The plasma torch is preferably one of a direct current plasma torch, an inductively coupled plasma torch, and a capacitively coupled plasma torch. By using such a plasma torch, a dense and high quality film can be obtained.

  The nozzle of the film forming means is preferably made of ceramics or cermet and is inclined at an angle of 60 ° to 120 ° with respect to the film forming target. In this case, a dense and high-quality film can be obtained.

  The conveying means generates a magnetic field in the conveying pipe having a conveying path for conveying the fine powder by gas in an air flow, and the electric field is generated in the direction different from the gas flow direction by the electric field. It is preferable to include an electric field generation unit that suppresses adhesion of the fine powder to the wall surface portion of the conveyance path by flying and moving.

  By such conveying means, the refined high-purity ceramic raw material powder can be introduced into the film forming means in an extremely stable state.

It is preferable to further include an airflow type or mechanical type crushing mechanism that crushes agglomerated particles having a particle size of 3 μm or more formed by agglomeration by the powder refining means to less than 3 μm. By providing the crushing mechanism, the agglomerated aggregated particles can be crushed to make the particle size adjustment more precise.

  It is preferable to further include a classification mechanism for removing fine powder having a size of less than 0.1 μm. By providing a classification mechanism, fine particles are classified to obtain a powder having a more optimal particle size, and a high-quality film can be obtained efficiently.

  The ceramic raw material powder is not limited. For example, any of oxide ceramics having an average particle diameter of 1 to 50 μm, nitride ceramics having an average particle diameter of 1 to 50 μm, and carbide ceramics having an average particle diameter of 1 to 50 μm Can be mentioned.

  By using the above configuration, the average particle diameter of the fine film forming powder introduced into the film forming means can be set to 0.1 to 3 μm, for example.

  The method for forming a ceramic film of the present invention comprises agglomeration of a ceramic raw material powder having an average particle diameter of 1 to 50 μm and agglomerated by agglomeration by agglomeration to an average particle diameter of 0.1 to 10 μm by high-frequency plasma. The grains are pulverized to less than 3 μm, and the refined powder of less than 0.1 μm is removed therefrom, and this refined powder is applied to the inner wall of the transport tube by applying an alternating electric field and an electrostatic field to the transport tube. Film is transported to prevent powder adhesion and blockage, and the transported micronized powder is sprayed onto a film formation target through one of a DC plasma torch, an inductively coupled plasma torch, and a capacitively coupled plasma torch. It is characterized by doing.

  In the manufacturing process that requires a large amount of raw material powder, such as when forming a film on a large base material or mass production because continuous processing is possible by using the ceramic film forming method of the present invention. The cost can be significantly reduced. Furthermore, the average particle size is reduced to 0.1 to 10 μm by high-frequency plasma, and the aggregated particles having a particle size of 3 μm or more obtained by agglomeration are crushed to less than 3 μm, and from these, refined powder of less than 0.1 μm is obtained. As a result, it is possible to obtain a powder having the optimum particle size for film formation, so that particles outside the optimum particle size range are not mixed into the raw material powder, and the film quality of the film is not reduced, and the amount of film formation is not reduced. can do.

  Further, by applying an AC electric field and an electrostatic field to the transfer tube, the transfer tube is transferred so as to prevent the powder from adhering to and clogging the inner wall of the transfer tube, and the transferred fine powder is converted into a DC plasma torch or inductively coupled plasma. The film is sprayed onto the film formation target through either a torch or a capacitively coupled plasma torch, so even highly refined raw material powder does not adhere to the inner wall of the transfer tube during gas transfer The powder supply amount does not decrease and the inside of the transport pipe is not blocked. As a result, the cost can be reduced, and at the same time, powder having an optimum particle size can be sprayed in a stable state, and a high-quality film can be formed.

  As described above, according to the present invention, since continuous processing is possible, costs can be greatly reduced even in a manufacturing process that requires a large amount of raw material powder. It is possible to obtain a powder having an optimum particle size for film formation, and particles outside the optimum particle size range are not mixed into the raw material powder, so that it is possible to prevent a decrease in film quality and a decrease in film formation amount. . Even a highly miniaturized raw material powder does not reduce the amount of powder supplied and does not block the inside of the transport tube. Thereby, the cost can be suppressed, and the powder having the optimum particle size can be supplied in a stable state, and a high-quality film can be formed.

1 is a schematic view of a ceramic film forming apparatus according to a first embodiment of the present invention. It is the schematic of the film-forming apparatus of the ceramic membrane | film | coat which concerns on 2nd Embodiment of this invention. It is the schematic of the film-forming apparatus of the ceramic membrane | film | coat concerning 3rd Embodiment of this invention. It is the schematic of the film-forming apparatus of the ceramic membrane | film | coat concerning 4th Embodiment of this invention. It is the schematic of the film-forming apparatus of the ceramic membrane | film | coat which concerns on 5th Embodiment of this invention. It is the schematic of the film-forming apparatus of the ceramic membrane | film | coat which concerns on 6th Embodiment of this invention. ₂ is a cross-sectional photograph of an Al ₂ O ₃ film formed in Example 1 using an electron microscope. 4 is a cross-sectional photograph of an Al ₂ O ₃ film formed in Example 2 by an electron microscope. It is a graph of output dependence of the plasma power source al ₂ O ₃ coating film forming amount. Al is a ₂ O ₃ film graph of output dependence of the plasma power Vickers hardness of the surface of the.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a ceramic film forming apparatus according to a first embodiment of the present invention. The film forming apparatus for ceramic film (hereinafter referred to as film forming apparatus) of the present embodiment manufactures a fine powder from a coarse powder, activates the surface of the refined raw material powder, and forms a base material that is a film forming target. The deposition is performed by spraying on the surface.

  The film forming apparatus includes a powder supply unit 5 as a powder supply unit that supplies raw material powder, a powder refinement unit 4 as a powder refinement unit that refines the ceramic raw material powder 1 to a predetermined particle size, and this powder. Conveying means 7 for conveying the micronized powder 2 discharged from the micronizing unit 4 by airflow, and a base material 3 that is the film forming target of the micronized powder 2 conveyed from the powder micronizing unit 4 via the conveying unit 7. The film forming unit 6 is provided as a film forming means for forming a film by spraying on the film.

The powder supply unit 5 is filled with a ceramic raw material powder 1, and a gas cylinder 13 for supplying a gas for conveying the powder 1 is connected to the powder supply unit 5. The structure of the powder supply unit 5 is not limited. For example, the powder supply unit 5 includes a powder storage unit and a rotating groove part with a circumferential groove, and the raw material powder charged into the powder storage part falls into the groove of the rotating disk by gravity and is filled. In addition, one that can supply a predetermined amount of the raw material powder by adjusting the rotation speed of the rotating disk is mentioned. The gas cylinder 13 is filled with one or more kinds of gases among oxygen, nitrogen, methane, argon, and helium, and this gas is supplied as a carrier gas.

  The powder refinement unit 4 is configured so that the ceramic raw material powder is refined by volatilizing the surface thereof by high frequency plasma, or the ceramic raw material powder is in a gas phase state by high frequency plasma and then cooled and precipitated. It is comprised so that it may refine or spheroidize. Specifically, the method described in Non-Patent Document 1 can be used, and the powder refinement unit 4 generates a supply port for supplying material powder, a plasma torch for generating thermal plasma, and fine particles. It consists of a chamber. The plasma torch is composed of a quartz tube and a coil that surrounds the quartz tube, and a thermal plasma is generated when a high frequency current is supplied to the coil by a high frequency power source.

  The ceramic raw material powder 1 is refined or spheroidized to an average particle size of 0.01 μm to 10 μm by the high frequency plasma by the powder refinement unit 4. A more preferable range of refining or spheroidizing is 0.01 μm to 3 μm in average particle diameter. In this case, the frequency for forming the high-frequency plasma is preferably 10 kHz to 13.56 MHz, and the output of the plasma power source is preferably 5 to 100 kW.

  The conveying means 7 is configured to prevent adhesion and blockage of the fine powder 2 on the inner wall of the conveying pipe by applying an alternating electric field and an electrostatic field to the conveying pipe. The details are as described in JP2010-241550A. The conveying means 7 has a conveying pipe having a conveying path for conveying the finely divided powder 2 by gas and an electric field in the conveying path, and the electric field causes the fined powder to fly in a direction different from the gas flow direction. Electric field generating means for suppressing adhesion of the fine powder to the wall surface portion of the conveyance path.

  In the transfer means 7, an AC electric field or an AC electric field and an electrostatic field by the AC power supply 14 for the transfer pipe are given to the transfer pipe by the double spiral electrode or the quadruple spiral electrode in the powder path to the nozzle 10 in the film forming unit 6. Thereby, adhesion and obstruction | occlusion of the micronized powder 2 to a conveyance pipe inner wall are prevented. Specifically, it is preferable that the voltage applied to the electrode is 0.5 to 10 kV, the frequency is 10 Hz to 1 kHz, and the carrier gas flow rate is 3 to 50 L / min.

  Thereby, the refined powder 2 can be supplied to the film forming unit 6 in a stable state for a long time. For example, when conveying the refined powder 2 having a particle size of 0.1 to 5 μm, an AC electric field is applied to the spiral electrode of the transport tube provided with the double spiral electrode, so that the refined powder 2 is not blocked. The fine powder 2 can be stably conveyed to the film forming unit 6.

  The film forming unit 6 is provided with a plasma torch 9 for heating the powder and a nozzle 10 attached to the torch 9 for injecting the heated powder onto the base material 3. In this embodiment, an inductively coupled plasma torch is used as the plasma torch 9. In the vacuum chamber of the film forming unit 6, an inductively coupled plasma torch 9 is attached to a movable arm 8 and is in a movable state. The inductively coupled plasma torch 9 generates plasma connected to an inductively coupled plasma power source 11. A coil 12 is wound around.

  The frequency for forming high-frequency plasma in the inductively coupled plasma torch 9 is preferably 10 kHz to 60 MHz, and the output of the inductively coupled plasma power source 11 is preferably 100 W to 3 kW. As a result, a heating state of several hundred degrees Celsius occurs during the film formation, the film formation speed is improved, and the film thickness can be increased. The shape of the nozzle 10 is preferably cylindrical, conical, or rectangular with an aspect ratio of 5 or less. Furthermore, it is more preferable that the nozzle 10 is made of ceramics or cermet and is inclined at an angle of 60 ° to 120 ° with respect to the substrate 3. In the film forming unit 6 configured as described above, the gas carrying the fine powder 2 is turned into plasma by the high frequency and high voltage of the plasma generating coil 12, and the fine powder 2 passes through the energy beam. The surface of the fine powder 2 is activated and deposited on the substrate 3 to form a film.

  The ceramic raw material powder 1 used in the film forming apparatus includes, for example, oxide ceramics having an average particle diameter of 1 to 50 μm, nitride ceramics having an average particle diameter of 1 to 50 μm, carbide ceramics having an average particle diameter of 1 to 50 μm, Examples thereof include boride-based ceramics having an average particle diameter of 1 to 50 μm, fluoride-based ceramics having an average particle diameter of 1 to 50 μm, and silicide-based ceramics having an average particle diameter of 1 to 50 μm. The average particle diameter of the refined powder 2 introduced into the film forming unit 6 is adjusted to, for example, 0.01 μm to 3 μm. And when the purity of the ceramic raw material powder 2 is 99.9% or more, the purity of the coating film formed on the substrate 3 can be 99.5% or more. For example, a film having an area of 500 × 500 mm or more can be formed on the substrate 3 and a film having a film thickness of 20 μm or more can be formed.

  According to the film forming apparatus of the present embodiment, the powder refinement unit 4 is configured to be refined by volatilizing the surface of the ceramic raw material powder by the high frequency plasma, or the ceramic raw material powder is evacuated by the high frequency plasma. It is configured to be fined or spheroidized by being cooled and precipitated, and the conveying means 7 is configured to prevent the powder from adhering to and clogging the inner wall of the conveying tube. And an inductively coupled plasma torch 9 for heating the nozzle and a nozzle 10 attached to the torch 9 for injecting heated powder onto the substrate 3.

  Therefore, continuous processing is possible, and costs can be significantly reduced even in manufacturing processes that require a large amount of raw material powder, such as when a film is formed on a large substrate or when mass production is performed. Furthermore, the powder refinement unit 4 can obtain a powder having an optimum particle size for film formation, and particles outside the optimum particle size range are not mixed into the raw material powder, so that the film quality of the film is reduced, the amount of film formation is reduced, etc. Can be avoided. Further, even if the raw material powder is highly miniaturized by the transport means 7, it does not adhere to the inner wall of the transport pipe during gas transport, and does not reduce the amount of powder supplied, and does not block the inside of the pipe. Thereby, the cost can be suppressed, and the powder having the optimum particle size can be supplied in a stable state, and a high-quality film can be formed.

  In addition to continuous processing, the coating time is significantly shortened compared to conventional batch processing. In addition, fine powder can be obtained from inexpensive raw powder, and high-purity powder with narrow particle size distribution can be obtained. And a high-purity film is obtained. Since it is a continuous process and it is possible to supply fine powder stably for a long time, it is easy to form a film over a wide range and to increase the thickness.

  Since the powder refinement | miniaturization part 4 is comprised so that the average particle diameter of the ceramic raw material powder 1 may be refined | miniaturized to 0.01-10 micrometers by high frequency plasma, it becomes a highly purified refined powder and can improve quality. . Since the frequency for forming the high-frequency plasma in the powder refinement unit 4 is 10 kHz to 13.56 MHz and the output of the plasma power source is 5 to 100 kW, it is possible to more appropriately adjust the particle size of the ceramic raw material powder. it can.

  By using the inductively coupled plasma torch 9, a dense and high-quality film can be obtained, the nozzle 10 of the film forming unit 6 is made of ceramics or cermet, and is 60 ° to 120 ° with respect to the film forming object. Since it is inclined at an angle, a dense and high-quality film can be obtained.

  FIG. 2 is a schematic view of a film forming apparatus according to the second embodiment of the present invention. This embodiment is different from the first embodiment in that the agglomerate having a particle size of 3 μm or more formed by agglomeration is pulverized to less than 3 μm, and an airflow type or mechanical crushing mechanism 15 and a fineness less than 0.1 μm. And a classification mechanism 16 for removing the powdered powder.

  The coarse ceramic raw material powder 1 is supplied from the powder supply unit 5 to the powder refinement unit 4 at 1 to 500 g / min. Aggregated particles having a particle diameter of 3 μm or more formed by agglomeration are crushed to less than 3 μm by the crushing mechanism 15, and at the same time, cracks are generated on the surface of the fine powder 2. By crushing the surface of the fine powder 2 by the crushing mechanism 15, the surface is activated and the compressive stress applied during film deposition can be relaxed. This makes it possible to improve the deposition rate and increase the thickness of the coating.

  The refined powder 2 crushed by the crushing mechanism 15 classifies fine particles of less than 0.1 mm by the classification mechanism 16 to prevent the fine particles from being mixed into the film. The classification mechanism 16 classifies the fine powder 2 by electrostatic force, centrifugal force, or both. Note that it is not necessary to provide a classification mechanism depending on various conditions such as the voltage applied to the ceramic raw material powder 1 and the plasma generating coil 12 and the film thickness to be applied.

  The ceramic film forming method realized by the film forming apparatus of the present embodiment is a method in which ceramic raw material powder 1 having an average particle diameter of 1 to 50 μm is refined and aggregated by high-frequency plasma to an average particle diameter of 0.01 to 10 μm. The agglomerated particles having a particle size of 3 μm or more are pulverized to less than 3 μm, and the fine powder 2 having a particle size of less than 0.1 μm is removed from the agglomerated powder. By feeding the fine powder 2 that has been conveyed so as to prevent the powder from adhering to and clogging the inner wall of the conveying tube, and the conveyed fine powder 2 is passed through the inductively coupled plasma torch 9, the substrate 3 that is a film formation target. This is a method of forming a film by spraying on the film.

  In the manufacturing process that requires a large amount of raw material powder, such as when forming a film on a large substrate or mass production because continuous processing is possible by using the method for forming a ceramic film of this embodiment. The cost can be significantly reduced. Furthermore, the average particle size is reduced to 0.01 μm to 10 μm by high-frequency plasma, and the aggregated particles having a particle size of 3 μm or more obtained by agglomeration are pulverized to less than 3 μm. Therefore, it is possible to obtain a powder with the optimum particle size for film formation, so that particles outside the optimum particle size range are not mixed into the raw material powder, so that the film quality of the film is not reduced and the amount of film formation is not reduced. Can be.

  Further, by applying an alternating electric field and an electrostatic field to the transport pipe, the transport pipe is transported so as to prevent the powder from adhering to and clogging the inner wall of the transport pipe, and the transported fine powder is passed through the inductively coupled plasma torch 9. Since the film is sprayed onto the substrate 3 to form a film, even if the raw material powder is highly miniaturized, it does not adhere to the inner wall of the transfer pipe during gas transfer and does not decrease the amount of powder supplied. Do not block. Thereby, the cost can be suppressed, and the powder having the optimum particle size can be supplied in a stable state, and a high-quality film can be formed.

  In addition to continuous processing, the coating time is significantly reduced compared to conventional batch processing. In addition, fine powder can be obtained from inexpensive raw material powder, and water and A high-purity powder having a narrow particle size distribution can be obtained without mixing impurities such as organic substances, and a high-purity film can be obtained. Furthermore, since it is a continuous process and it is possible to supply fine powder stably for a long time, it is easy to form a film over a wide range and to increase the thickness.

  FIG. 3 is a schematic view of a film forming apparatus according to the third embodiment of the present invention. This embodiment is different from the first embodiment in that a capacitively coupled plasma torch 17 is used for the plasma torch. The capacitively coupled plasma torch 17 is provided with a plasma generating electrode 18 connected to a capacitively coupled plasma power source 19, and the gas for transporting the fine powder 2 by the high frequency and high voltage of the electrode 18 is converted into plasma. Then, when the fine powder 2 passes through the energy beam, the surface of the fine powder 2 is activated and deposited on the base material 3 to form a film. When the capacitively coupled plasma torch 17 is used as in the present embodiment, the frequency for forming the high frequency plasma is preferably 10 kHz to 60 MHz, and the output of the capacitively coupled plasma power source 19 is preferably 100 W to 3 kW.

  FIG. 4 is a schematic view of a film forming apparatus according to the fourth embodiment of the present invention. This embodiment is different from the third embodiment in that the agglomerate having a particle size of 3 μm or more formed by agglomeration is crushed to less than 3 μm, and an airflow type or mechanical crushing mechanism 15 and a fineness less than 0.1 μm. And a classification mechanism 16 for removing the powdered powder.

  FIG. 5 is a schematic view of a film forming apparatus according to the fifth embodiment of the present invention. This embodiment is different from the first and third embodiments in that a DC plasma torch 20 is used for the plasma torch. The direct current plasma torch 20 is provided with a positive electrode 21 and a negative electrode 22 connected to a direct current plasma power source 23. Fine powder 2 is supplied from the axial center of the direct current plasma torch 20, and the inside of the plasma gas is refined. By passing the powder 2, the surface of the fine powder 2 is activated and deposited on the substrate 3 to form a film. When the DC plasma torch 20 is used as in the present embodiment, the output of the DC plasma power source 23 is preferably 5 to 100 kW.

  FIG. 6 is a schematic view of a film forming apparatus according to the sixth embodiment of the present invention. This embodiment differs from the fifth embodiment in that an airflow type or mechanical type crushing mechanism 15 that crushes a refined powder having a particle size of 5 μm or more to less than 3 μm and a refined powder less than 0.1 μm are removed. The classification mechanism 16 is further provided. With such a film forming apparatus, the above-described method for forming a ceramic film can be realized, the cost can be suppressed, and at the same time, a powder having an optimum particle size can be supplied in a stable state, thereby forming a high-quality film. Can be membrane.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to this Example. Using the film forming apparatuses of the first to sixth embodiments, films were formed on the base material under the same conditions other than the conditions based on the configuration unique to each apparatus. The film formation speed and film quality of each embodiment were evaluated in four stages of ◎ to ×. The results are shown in Table 1. The film structure, film formation speed, and film quality produced in the second, fourth, and sixth embodiments were substantially the same. The films created in the first, third, and fifth embodiments were generally inferior in film formation rate to the second, fourth, and sixth embodiments.

  Whether or not film formation is possible due to differences in ceramic raw material powder (material), refinement conditions in the powder refinement section (frequency for generating plasma, power supply output), type of plasma torch, presence / absence of crushing / classifying section Is shown in Table 2.

Example 1
Film formation was performed by the method using the inductively coupled plasma torch of the first embodiment shown in FIG. 2 kg of aluminum oxide (Al ₂ O ₃ ) having a particle size of 20 μm is placed in the powder supply chamber, Ar gas supplied from a gas cylinder at 20 g / min is flowed at 10 L / min, and supplied to the powder refinement unit. The Al ₂ O ₃ powder is refined to a particle size of 0.1 to 2 μm in the powder refinement section. The particle size of the refined powder produced in the powder refinement unit was measured using a particle size distribution measuring device (GRANULOMERTRE 1064, manufactured by CILAS). The micronized Al ₂ O ₃ powder was passed through a transfer tube in which an AC voltage of AC 4.5 kV was applied to a double spiral electrode, and was transferred into a film forming chamber at a pressure of 20 Pa. The conveyed Al ₂ O ₃ powder is introduced into an inductively coupled plasma torch using O ₂ as a plasma gas, a power of 800 W is applied to the plasma generating coil, and an area of 500 × 500 mm on a glass substrate for 1 h. The film was formed.

FIG. 7 shows a cross-sectional photograph of the Al ₂ O ₃ film formed in Example 1 using an electron microscope. Although voids are observed inside the film, it is firmly adhered to the substrate. It can be understood that a film having a thickness of 10 μm or more can be easily formed because the compressive stress applied to the base material is reduced by applying heat to the fine powder particles during film deposition.

(Example 2)
Film formation was performed by the method using the inductively coupled plasma torch of the second embodiment shown in FIG. 2 kg of Al ₂ O ₃ powder having a particle size of 16 μm is placed in the powder supply chamber, Ar gas supplied from a gas cylinder at 20 g / min is flowed at 20 L / min, and supplied to the powder refinement unit. In powders finer unit, the _Al 2 _{O 3} powder, refining the particles 0.1～4Myuemu. When this was pulverized in the crushing chamber, the fine particles were further crushed to 0.1 to 1.6 μm. The particle size of the refined powder produced in the powder refinement unit and the refined powder crushed in the crushing chamber were measured using a particle size distribution measuring device (CRANAS, GRANULOMERTRE 1064). The refined Al ₂ O ₃ powder was passed through a double spiral electrode through a transfer tube to which an AC voltage of 6 kV was applied, and was introduced into a film forming chamber at a pressure of 20 Pa. The introduced Al ₂ O ₃ powder is introduced into an inductively coupled plasma torch using O ₂ as a plasma gas, a power of 900 W is applied to the plasma generating coil, and an area of 500 × 500 mm on the glass substrate for 1 h. The film was formed.

FIG. 8 shows a cross-sectional photograph of the Al ₂ O ₃ film formed in Example 2 using an electron microscope. It is recognized that the surface of the powder is activated by crushing the fine powder with a crushing mechanism and giving cracks, and the powder is firmly adhered to the substrate. By providing the crushing mechanism and the classification mechanism, the ratio of the fine powder that contributes to the film formation increased more than in Example 1, and the film formation speed was improved. This is a film formation rate about 10 times that of the conventional AD method.

(Example 3)
Film formation was performed by the method using the DC plasma torch of the fifth embodiment shown in FIG. 2 kg of Al ₂ O ₃ powder having a particle size of 3 μm is placed in the powder supply chamber, Ar gas supplied from a gas cylinder at 20 g / min is flowed at 10 L / min, and supplied to the powder refinement unit. In powders finer unit, the _Al 2 _{O 3} powder, refining the particles of 0.1-2 .mu.m. The particle size of the refined powder produced in the powder refinement unit was measured using a particle size distribution measuring device (GRANULOMERTRE 1064, manufactured by CILAS). The micronized Al ₂ O ₃ powder is passed through a carrier tube in which an alternating voltage of 7 kV is applied to a double spiral electrode, introduced into a direct current plasma torch in a film forming chamber at a pressure of 20 Pa, and glass having an area of 500 × 500 mm. A film was formed on the substrate for 1 h.

In the Al ₂ O ₃ film formed in Example 3, a green compact was partially formed. When the crushing mechanism and the classification mechanism were used in Example 2, a film was formed without forming the green compact. On the other hand, the crushing mechanism and the classification mechanism are not installed in this embodiment. Therefore, it is considered that the formation of the green compact is due to the fact that the fine powder aggregates and a closed state is generated by the fine powder near the direct current plasma torch and the fine powder cannot be supplied stably.

FIG. 9 shows the results of measuring the output dependence of the plasma power supply of the amount of Al ₂ O ₃ coating formed using the method using the inductively coupled plasma torch of the second embodiment shown in FIG. This is the amount of film formation when Ar gas is flowed at 20 L / min as the carrier gas, AC 6 kV is applied to the double spiral electrode, and the film is formed on the glass substrate for 1 h with an area of 500 × 500 mm. The horizontal axis of the graph of FIG. 9 is the output of the plasma power source, and the vertical axis is the film thickness when the film is formed at 1 cm ² for 1 min. It can be seen that the deposition rate increases as the output of the plasma power supply increases.

FIG. 10 shows the results of measuring the dependence of the Vickers hardness on the surface of the Al ₂ O ₃ coating on the output of the plasma power source using the method using the inductively coupled plasma torch of the first embodiment shown in FIG. This is the amount of film formation when Ar gas is flowed at 10 L / min as the carrier gas, applied to the double spiral electrode at AC 4.5 kV, and deposited on the glass substrate for 1 h with an area of 500 × 500 mm. The Vickers hardness was measured using a micro Vickers hardness meter (manufactured by Akashi Seisakusho, HM-124). The measurement conditions are a load of 245.2 mN and holding for 15 s. The horizontal axis of the graph of FIG. 10 is the output of the plasma power source, and the vertical axis is the Vickers hardness. It is recognized that the hardness of the surface of the Al ₂ O ₃ film decreases as the output of the plasma power source increases. The reason for the decrease in hardness is considered to be a decrease in the film density due to the improvement in the amount of film formation, as shown in the sectional photograph of the film shown in FIG.

  The embodiments and examples disclosed above are illustrative and not restrictive. For example, if necessary, the ceramic film deposition apparatus of the present invention may be provided with other configurations, and each part, the configuration of each mechanism, powder conveyance conditions, miniaturization conditions, film deposition conditions, and the like are appropriately changed.

DESCRIPTION OF SYMBOLS 1 Ceramic raw material powder 2 Refined powder 3 Base material 4 Powder refined part 5 Powder supply part 6 Film-forming part 7 Conveying means 8 Movable arm 9 Inductively coupled plasma torch 10 Nozzle 11 Inductively coupled plasma power supply 12 Plasma generating coil 13 Gas cylinder 14 AC power source for carrier tube 15 Crushing mechanism 16 Classification mechanism 17 Capacitive coupling plasma torch 18 Plasma generating electrode 19 Capacitive coupling plasma power source 20 DC plasma torch 21 Positive electrode 22 Negative electrode 23 DC plasma power source

Claims (11)

A powder refining means for refining ceramic raw material powder to a predetermined particle size;
Conveying means for conveying the refined powder discharged from the powder refining means with an air current through a conveying tube;
A film forming means for injecting the fine powder conveyed from the powder refining means through the conveying means onto a film formation target, and forming a film;
The powder refinement means is configured such that the ceramic raw material powder is refined by volatilizing the surface thereof by high frequency plasma, or the ceramic raw material powder is in a gas phase state by high frequency plasma and then cooled and precipitated. Configured to refine,
The transport means is configured to prevent adhesion and blockage of powder on the inner wall of the transport pipe by applying an alternating electric field and an electrostatic field to the transport pipe.
The film forming means includes a plasma torch for heating powder, and a nozzle attached to the torch for injecting heated powder onto a film forming object.   2. The ceramic film forming apparatus according to claim 1, wherein the powder refinement means is configured to refine the average particle size of the ceramic raw material powder to 0.01 to 10 [mu] m by high frequency plasma. .   3. The ceramic film-forming apparatus according to claim 2, wherein a frequency for forming the high-frequency plasma in the powder refinement means is 10 kHz to 13.56 MHz, and an output of the plasma power source is 5 to 100 kW. .   4. The ceramic film forming apparatus according to claim 1, wherein the plasma torch is any one of a direct current plasma torch, an inductively coupled plasma torch, and a capacitively coupled plasma torch.   5. The ceramic according to claim 1, wherein the nozzle of the film forming means is made of ceramic or cermet and is inclined at an angle of 60 ° to 120 ° with respect to the film forming target. Film deposition equipment. The conveying means is
A transport pipe having a transport path for air transporting the fine powder by gas;
Generation of an electric field that suppresses adhesion of the refined powder to the wall surface of the transport path by generating an electric field in the transport path and causing the electric field to fly and move the refined powder in a direction different from the gas flow direction. And a ceramic film forming apparatus according to any one of claims 1 to 5. 2. An airflow type or mechanical type crushing mechanism for crushing agglomerated particles having a particle diameter of 3 μm or more formed by agglomeration by the powder refining means to less than 3 μm is further provided. The film-forming apparatus of the ceramics film in any one of -6.   The film forming apparatus for a ceramic film according to claim 1, further comprising a classification mechanism for removing the fine powder having a size of less than 0.1 μm.   The ceramic raw material powder is any one of oxide ceramics having an average particle diameter of 1 to 50 μm, nitride ceramics having an average particle diameter of 1 to 50 μm, and carbide ceramics having an average particle diameter of 1 to 50 μm. The film forming apparatus for a ceramic film according to claim 1.   10. The ceramic film-forming apparatus according to claim 1, wherein an average particle diameter of the refined powder introduced into the film-forming means is 0.1 to 3 μm.   A ceramic raw material powder having an average particle size of 1 to 50 μm is refined to an average particle size of 0.1 to 10 μm by high-frequency plasma, and agglomerated particles having a particle size of 3 μm or more obtained by agglomeration are crushed to less than 3 μm. The fine powder of less than 0.1 μm is removed from this, and this fine powder is conveyed so as to prevent the powder from adhering to and clogging the inner wall of the conveyance pipe by applying an AC electric field and electrostatic field to the conveyance pipe. Film formation of a ceramic film, characterized in that the fine powder that has been conveyed is sprayed onto a film formation object through any one of a direct current plasma torch, an inductively coupled plasma torch, and a capacitively coupled plasma torch. Method.