JP2008119659A - Powder film formation apparatus and powder film formation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder film formation apparatus and a powder film formation method capable of efficiently forming a uniform powder film on the surface of a substrate. <P>SOLUTION: The powder film formation apparatus comprises a particulate production means B for pulverizing a raw material m by applying external mechanical force to the raw material m by relatively moving a treatment container 2 storing and holding the raw material m and a pressurizing member 1 arranged adjacently to the inner circumferential face of the treatment container 2, a substrate holding means 4 for holding a substrate A to which the particulates C immediately after production by the particulate production means B are deposited, and a compressive force application means D for applying a compressive force to the particulates C deposited on the substrate A. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a powder film forming apparatus and a powder film forming method for forming a powder film on a surface of a substrate by attaching fine particles.

When forming a powder film by attaching fine particles to the surface of the substrate, for example, fine particles having a size in the nanometer to micrometer range are used. When a powder film having a porous structure (porous structure) is formed using such fine particles, the specific surface area becomes very large, and for example, a highly active catalyst material can be obtained.
Conventionally, as an apparatus for forming a powder film on the surface of a substrate, for example, there are apparatuses disclosed in Patent Documents 1 and 2.

Patent Document 1 discloses a powder film forming apparatus to which an aerosol deposition method is applied that can form a ceramic powder film on a substrate by injecting and solidifying, for example, a raw material that is ceramic fine particles onto the substrate. Is disclosed.
In the aerosol deposition method, a raw material having a particle size of several tens to several hundreds of nanometers is usually aerosolized, pressurized by an injection nozzle, and then injected onto a film-forming object such as a substrate disposed in a low-pressure chamber. . As a result, the particulate material is solidified to form a powder film.

  The injection nozzle in the apparatus of Patent Document 1 has an introduction direction of the assist gas introduced from the second introduction path at an angle of, for example, less than 90 degrees with respect to the introduction direction of the aerosol gas containing fine particles introduced from the first introduction path. It is set. Thus, the injection pressure of aerosol gas is raised by joining both gas.

  By doing so, the flow velocity of the aerosol gas increases and the assist gas easily flows along the inner wall of the injection nozzle, so that the fine particle material of the aerosol gas hardly adheres to the inner wall. As a result, a good quality film can be stably formed over a long period of time.

  Patent Document 2 discloses a powder film forming apparatus in which fine particle generating means is configured by a processing container disposed inside a casing and a press head disposed inside the processing container. In this apparatus, the transport state of the generated fine particles until reaching the substrate is controlled. Accordingly, the fine particles can be attached to the substrate while preventing the fine particles from aggregating, and a uniform powder film can be formed on the surface of the substrate.

Graphite (graphite) is often used as a raw material for fine particles. Graphite is known as a layered material, and is a material in which atoms are strongly bonded by a covalent bond or the like and densely arranged surfaces are stacked in parallel by a weak bonding force such as Van der Waals force.
In order to produce a layered alignment film of graphite on the surface of a substrate, it is known to apply a vapor phase method such as a CVD method (Chemical Vapor Deposition) or a PLD method (Pulsed Laser Deposition).

  For example, Patent Document 3 describes a technique for forming a conductive graphite film by a CVD method. In the CVD method, first, a compound containing a constituent element of a material for which a thin film is to be formed is vaporized to obtain a raw material gas. This source gas is supplied onto the substrate, and a thin film is formed by a chemical reaction on the substrate surface. The raw material gas undergoes a chemical reaction by the action of heat, plasma, or the like. According to this method, various types of thin films can be formed. For example, as shown in Patent Document 3, a thin film that maintains the characteristics of graphite can be formed on a substrate.

JP 2005-163058 A JP 2006-150160 A Japanese Patent No. 2779413

In order to increase the activity of the powder film formed on the substrate, it is necessary to increase the specific surface area. Therefore, it is preferable to reduce the particle size of the fine particles to be deposited on the substrate as much as possible. For example, so-called nanoparticles having a particle size of about 1 to 100 nm are suitable.
However, when the particle size is reduced, the fine particles collide with each other and tend to agglomerate between the time when the fine particles are ejected and the time when they are attached to the surface of the substrate. For this reason, the particle size constituting the powder film is not stable, and a homogeneous powder film cannot be formed. As a result, the specific surface area of the obtained powder film cannot be sufficiently increased.

  In the apparatus of Patent Document 1, the quality of the film formed by the aerosol deposition method depends on the flow rate of the gas to be sprayed, and the higher the gas flow rate, the higher the quality film is formed. In this apparatus, an assist gas is introduced into the aerosol gas containing the raw material to increase the spray pressure of the aerosol gas and increase the collision speed with the substrate. However, in this apparatus, since the separately produced raw material is collided with the substrate through the path in the injection nozzle, there is a possibility that the fine particles may aggregate during that time.

  In the apparatus of Patent Document 2, the fine particles generated by the fine particle generating means float on the inside of the casing and adhere to the substrate disposed outside the processing container. For this reason, in order to form a better powder film, it is necessary to prevent the fine particles generated in the processing container from aggregating before reaching the substrate.

  In addition, when attempting to form a film by a vapor phase method, the film formation is at the atomic level, so the film formation rate is very slow, and is not suitable for industrial production in terms of efficiency. This is also not preferable in that a special device such as an ion or plasma discharge electrode with high equipment costs is required.

  Accordingly, an object of the present invention is to provide a powder film forming apparatus and a powder film forming method capable of efficiently forming a homogeneous powder film on the surface of a substrate.

  The first characteristic configuration of the present invention for achieving the above object is that the raw material is mechanically moved to the raw material by the relative movement of the processing container that contains and holds the raw material and the pressing member that is disposed close to the inner peripheral surface of the processing container. A fine particle generation unit that applies external force to atomize the raw material, and a substrate holding unit that holds a substrate to which the fine particles immediately after generated by the fine particle generation unit are attached, and compresses the fine particles attached to the substrate. It is in the point which was set as the powder film forming apparatus provided with the compression force provision means to provide.

According to this configuration, the fine particles immediately after being generated by the fine particle generating means are adhered to the substrate to form a powder film, and therefore the aggregation of the fine particles is extremely small. That is, the fine particles floating inside the processing container immediately after generation reach the vicinity of the substrate held by the substrate holding means, and the fine particles flow along the surface of the substrate in a dispersed state. At this time, since the surface of the fine particles is activated, the fine particles that have reached the substrate easily adhere to the surface of the substrate.
In this way, with this configuration, a homogeneous powder film can be obtained under non-heating / dry process conditions using the surface energy of the fine particles.

In addition, since the apparatus of this configuration has a compressive force imparting means, pressing the fine particles already adhered on the substrate further brings the activated surfaces of the fine particles close together, thereby bonding the fine particles more firmly. Can do.
For example, when a material having a layered structure is used as a raw material, when a mechanical external force is applied to the raw material by the fine particle generating means, flaky fine particles with an activated surface appear, and the fine particles reach the substrate and are sequentially stacked. Is done. However, since the fine particles have a large size and are flaky in shape, the activated surfaces of the respective fine particles cannot sufficiently approach each other. Therefore, a strong film cannot be formed simply by laminating flaky fine particles.
However, in this configuration, by pressing the laminated fine particles by the compressive force applying means, the activated surfaces of the flaky fine particles are sufficiently close to each other, and the directionality of the flaky fine particles is maintained and uniform. Thus, a strongly bonded film is formed in a state having a proper orientation.
As a result, a homogeneous powder film can be efficiently formed on the surface of the substrate.

  The second characteristic configuration of the present invention is that, in the above-described powder film forming apparatus, the compressive force applying means includes a pressure member that abuts on the fine particle adhesion surface of the substrate.

  According to this configuration, a compressive force can be directly applied to the powder film formed on the surface of the substrate. Therefore, the density of the powder film can be controlled more accurately.

  According to a third feature of the present invention, in the above-described powder film forming apparatus, the pressurizing member applies a compressive force at a preset position, and the substrate holding unit applies the compressive force by the pressurizing member. A slide mechanism for sliding the substrate with respect to a position is provided.

  According to this configuration, the powder film formed on the substrate by applying a compressive force at a preset position, sliding the substrate, and changing the position of the substrate to which the pressing member applies the compressive force. A compressive force is equally applied to the entire area. As a result, a powder film having a uniform density and the like can be formed in a wide area.

  According to a fourth characteristic configuration of the present invention, in the above-described powder film forming apparatus, the substrate holding unit includes a compression force relaxation mechanism that relaxes the compression force applied to the fine particles attached to the substrate by the compression force applying unit. In the point.

  By providing the compression force relaxation mechanism as in this configuration, it is possible to prevent an excessive pressurizing force from being applied when the substrate is pressed by the pressing member. Accordingly, it is easy to form a powder film having a desired powder density.

  According to a fifth feature of the present invention, the raw material is imparted with mechanical external force by relative movement of the processing container that contains and holds the raw material and the pressing member that is disposed close to the inner peripheral surface of the processing container. Forming a powder film, comprising: a fine particle forming step for forming a fine particle; a fine particle attaching step for attaching the fine particles immediately after the fine particle formation to a substrate; and a compressive force applying step for applying a compressive force to the fine particles attached to the substrate. It is in the point which was a method.

If the fine particles immediately after being produced are adhered to the substrate by the fine particle forming step and the fine particle attaching step as in this configuration, the fine particles are not agglomerated as described in the section regarding the first characteristic configuration. The substrate can be reached. As a result, a homogeneous powder film can be obtained under non-heated / dry process conditions.
Further, as in this configuration, by providing a compressive force application step, it is possible to further apply a compressive force to the laminated fine particles to increase the adhesion between the fine particles. With this configuration, a strong powder film can be formed even when fine particles having relatively large sizes, which are difficult to adhere to each other simply by being laminated, are used. Moreover, since fine particles having a large particle diameter can be used, a powder film can be formed extremely efficiently.

  A sixth characteristic configuration of the present invention is that the above-described powder film forming method includes a friction control step of controlling a friction coefficient of the raw material.

By controlling the friction coefficient of the raw material as in this configuration, the magnitude of the external force applied to the raw material when the raw material is pulverized can be changed, and the pulverization speed, the size of the generated fine particles, and the like can be controlled.
For example, by reducing the friction coefficient, the force applied to the fine particles is reduced, the efficiency of pulverization is lowered, and large-sized fine particles are easily obtained. On the other hand, by increasing the friction coefficient, it is possible to increase the force applied to the fine particles, increase the pulverization efficiency, and obtain fine particles with a small size.

  A seventh characteristic configuration of the present invention is that, in the above-described powder film forming method, the friction control step is a step of changing the degree of vacuum.

By changing the degree of vacuum as in this configuration, the amount of gas intervening between the raw material particles can be adjusted.
For example, increasing the degree of vacuum reduces the amount of gas present between the raw material particles. As a result, the raw material particles are closer to each other and easily collide with each other, and the force is easily transmitted between them, so that the pulverization efficiency is increased. On the other hand, when the degree of vacuum is lowered, the amount of gas between the raw material particles increases, it becomes difficult to collide with each other, the force acting between the raw material particles is reduced, and the pulverization efficiency is lowered.
Further, for example, in the case of graphite particles, the oxygen partial pressure is reduced by increasing the degree of vacuum, so that adsorption of oxygen molecules to the particle surface is reduced, and the coefficient of friction between the raw material particles can be increased. As a result, the force acting between the raw material particles is increased and the grinding efficiency is improved.
Thus, by using a simple method of changing the degree of vacuum, the size of the fine particles obtained can be changed, and the grinding efficiency can be adjusted.

  The eighth characteristic configuration of the present invention is that, in the above-described powder film forming method, the friction control step is a step of changing the atmospheric gas.

  Depending on the raw material for forming the powder film, for example, it may be necessary to perform pulverization in an inert gas atmosphere for the purpose of preventing oxidation. In such a case, if the conditions of the atmospheric gas species can be changed as in the present configuration, the friction coefficient of the raw material is controlled and the obtained fine particles Size and grinding efficiency can be adjusted.

  A ninth characteristic configuration of the present invention is that, in the above-described powder film forming method, the friction control step is a step of adding different kinds of particles different from the raw material.

In order to adjust the coefficient of friction of the fine particles, in addition to controlling the gas as described above, it is also effective to disperse other fine particles around the fine particles as a raw material. That is, the fine particles added to be dispersed intervene between the fine particles to be pulverized to exhibit the function of the rolling member, so that the friction coefficient between the fine particles to be pulverized can be reduced.
Further, if different kinds of particles different from the raw material are added, a powder film made of a plurality of types of materials can be obtained. For example, various powder films having different electrical characteristics can be formed.

Embodiments of the present invention will be described below with reference to the drawings.
In the powder film forming apparatus of the present invention, nano-sized fine particles can be attached to the surfaces of various substrates such as sensors and fuel cell electrolyte substrates to form a powder film.

  As the fine particles, for example, those formed by applying a mechanical external force such as a compressive force, a shear force, and an impact force to a massive solid that is a raw material of the fine particles can be used. As the size and shape of the fine particles, those having various shapes and sizes can be used by appropriately setting raw materials and pulverization methods from extremely fine spherical shapes to relatively large pieces.

  In the present embodiment, for example, a case where a raw material having a layered structure is used will be described. When a mechanical external force is applied to, for example, graphite (graphite) serving as an electrode material as such a raw material substance, the graphite is cleaved into layers to obtain flaky fine particles. Hereinafter, a case where a powder film having a laminated structure is formed using the flaky fine particles will be described.

[Powder film forming equipment]
As shown in FIGS. 1 to 3, the powder film forming apparatus X according to the present invention is close to the processing container 2 that contains and holds the raw material m to be atomized, and the inner peripheral surface 2 a of the processing container 2. And a pressing member 1 provided. The pressing member 1 and the processing container 2 constitute the fine particle generation means B, and a mechanical external force is applied to the raw material m by relative movement of these two members, thereby pulverizing the raw material m. At least one of the pressing member 1 and the processing container 2 rotates and relatively moves. In the present embodiment, the processing container 2 is fixed, and the pressing member 1 rotates inside the processing container 2.
The substrate holding means 4 for holding the substrate A to which the fine particles immediately after being generated by the fine particle generating means B are attached is disposed at a position close to the fine particle generating means B along the direction of the inner peripheral surface 2a of the processing container 2. It is.
Furthermore, in the present invention, a compressive force applying means D for applying a compressive force to the fine particles attached to the substrate A is provided.

(Pressing member)
The pressing member 1 is a member that applies a pressing force to the raw material and crushes the raw material.
The pressing member 1 is composed of a press head 1 </ b> A that is held by a shaft 11 that is rotatable about a horizontal axis Z of the processing container 2. A processing surface 1a curved in a convex shape is formed at the tip of the press head 1A so as to face the inner peripheral surface 2a of the processing container 2.
The entire side cross-sectional shape of the press head 1A can be formed in, for example, an egg shape or a rod shape. In addition to this, various shapes such as a rotor having a circular cross section and an appropriate number of processing surfaces provided on the peripheral edge of the rotor can be adopted.

  The powder film forming apparatus X is provided with a rotation driving means 12 including a motor, a pulley, a belt, and the like that rotationally drive the shaft body 11. The rotation driving unit 12 rotates the shaft body 11 to move the press head 1 </ b> A relative to the processing container 2. Here, the processing surface 1a of the press head 1A is moved relative to the inner peripheral surface 2a of the fixed processing container 2. By this relative movement, mechanical energy of a very strong compressive force and shear force is applied to the raw material m in the gap 7 between them. As a result, the raw material m is ground and a fine powdery generated powder C whose surface is activated is obtained. In such a fine particle generating means B, the portion where the generated powder C is generated is particularly the opposite portion between the processing surface 1a and the inner peripheral surface 2a.

(Processing container)
The processing container 2 is a cylindrical member that is fixedly installed on the base 5 and has a horizontal axis Z.
Inside the processing container 2, a cylindrical processing chamber 3 in which the press head 1A rotates is formed. The processing chamber 3 is a fine particle generation space, and the generated powder C generated by the mechanical external force applied to the raw material m during the relative rotation of the press head 1A and the processing container 2 circulates and floats inside the processing chamber 3. .
A gap 7 is formed between the processing surface 1a of the press head 1A and the inner peripheral surface 2a, and the raw material m supplied from the raw material charging means 90 is deposited on the inner peripheral surface 2a.

A recess 31 for receiving the substrate holding means 4 is provided in a part of the inner peripheral surface 2a. In this embodiment, a film is formed on the substrate A in the recess 31.
The recess 31 is located above the axis Z of the processing container 2 and is recessed vertically upward. The recess 31 is provided with an opening 32 that partially communicates with the processing chamber 3. The substrate A faces the processing chamber 3 from the opening 32. As a result, the produced powder C circulating and floating inside the processing chamber 3 adheres to the substrate A.

When the produced powder C is attached to the substrate A at the position of the opening 32, the processing powder is introduced from the side of the recess 31 to prevent the produced powder C from entering the inside of the recess 31 through the opening 32. Gas is circulated on the side 3 (FIG. 3). As the gas, air filled in the processing chamber 3 or various inert gases are used. A gas inflow portion 24 for supplying gas to the concave portion 31 is provided in the concave portion 31, and a gas outflow portion 25 for allowing the gas in the processing chamber 3 to flow out of the processing chamber 3 is provided in the processing chamber 3. At this time, for example, one end of the gas outflow portion 25 is provided inside the shaft body 11 so that the axis of the shaft body 11 and the center of the gas outflow portion 25 coincide with each other, and the processing chamber 3 and the gas outflow portion 25 are provided. Keep in communication.
The gas flowing out of the processing chamber 3 may be recirculated to the recess 31 again.

(Compression force applying means and substrate holding means)
The substrate holding means 4 is arranged so that the substrate A constitutes a part of the inner peripheral surface 2 a of the processing container 2. The substrate holding means 4 includes a plate-like holding member 41, a slide mechanism E and a compressive force relaxation mechanism G which will be described later.

  The surface of the powder film F formed on the surface of the substrate A is disposed on the tangent L of the rotation circle drawn by the pressing member D which is a compressive force applying means (FIG. 2). Here, the “pressurizing member D” refers to a member to which a compressive force can be directly applied by contact with the powder film F formed on the fine particle adhesion surface of the substrate A. The position where the compression force is applied is referred to as a compression force application position N. In this embodiment, the contact point when the substrate A is disposed at the position of the tangent L with respect to the rotation circle of the pressure member D is the compression force application position N. It becomes.

In the powder film forming apparatus X of the present invention, the material of the substrate A is not particularly limited. Therefore, as the substrate A, for example, various materials such as a metal substrate such as copper, a glass substrate, a plastic substrate, a resin substrate, a ceramic substrate, and a weakly heat-resistant substrate constituting electrodes can be used.
The produced powder C adheres to the surface of the substrate A by van der Waals force, electrostatic force, chemical bond, or the like. Therefore, it is preferable to select a substrate material according to the type of raw material used so that a desired adhesion state can be obtained.

The substrate holding means 4 includes a slide mechanism E that slides the substrate A with respect to the compression force applying position N by the pressing member D.
The slide mechanism E is constituted by rails arranged along the wall surface of the recess 31 and driving means for generating power for sliding the substrate A. The rail is arranged in parallel with the tangent L of the rotation circle drawn by the pressure member D.
Note that it is conceivable that the processing chamber 3 and the recess 31 communicate with each other through the opening 32 along with the slide movement. At this time, the holding member 41 that directly holds the substrate A is configured such that the area of the holding member 41 facing the processing chamber 3 is increased. Thereby, it is possible to prevent the generated powder C in the processing chamber 3 from entering the recess 31 via the opening 32 as the substrate A slides by the slide mechanism E.

  The substrate A is arranged on the tangent L of the rotation circle of the pressure member D. When the slide mechanism E slides the substrate A along the tangent line L, all parts of the powder film F pass through the compression force applying position N. Therefore, a compressive force can be applied to the entire powder film F formed on the substrate A. Therefore, when the compression force application position N by the pressure member D is fixed as in this configuration, the substrate A is slid to move the powder film F over the entire characteristics of the powder film F. It can be controlled uniformly.

The substrate holding means 4 includes a compression force relaxation mechanism G that relaxes the compression force applied to the generated powder C attached to the substrate A by the pressure member D.
In this embodiment, the case where the compression force relaxation mechanism G is comprised with a spring member is shown.
That is, the holding member 41 that directly holds the substrate A is supported inside the recess 31 by the plurality of spring members 43. At this time, for example, one end of the spring member 43 is connected to the holding member 41 and the other end is connected to the slide mechanism E.

Thus, when the pressing member D presses the substrate A, the compressing force relaxation mechanism G relaxes the compressing force of the pressing member D against the substrate A, that is, the substrate A is separated from the pressing member D. The substrate A can be retracted in the direction. The degree of relaxation of the compressive force by the pressure member D can be variously set by changing the spring constant of the spring member.
Therefore, by providing the compression force relaxation mechanism G, the powder density and the like of the powder film F formed on the surface of the substrate A can be easily controlled to a desired value.

The pressing member D is a means for applying a compressive force to the generated powder C attached to the substrate A.
For example, the pressurizing member D is composed of a pressurizing member D that can contact the substrate A. Thereby, a compressive force can be directly applied to the generated powder C adhered to the surface of the substrate A, and the powder film F can be formed. Therefore, the powder density and the like of the powder film F can be accurately controlled.

In the present embodiment, the processing surface 1a of the press head 1A is a pressure member D. This is in common with the processing surface 1a of the pressing member 1 that imparts mechanical energy to the raw material m as the fine particle generation means B. The pressure member D rotates around the axis Z.
Thus, the structure of the powder film forming apparatus X can be simplified by using the pressing member 1 and the pressing member D as a common member.

  The pressurizing member D intermittently applies a compressive force to the powder film F located at the compressive force applying position N every time it rotates once. By intermittently applying a compressive force to the powder film F in this way, it is possible to alternately apply fine particles to the substrate and apply compressive force to the attached fine particles. Therefore, a constant compressive force can be applied to the powder film F from the initial stage to the later stage of film forming, and a uniform powder film can be formed over the entire thickness direction of the film thickness. Can do.

In the powder film forming apparatus X of the present invention, the fine particles immediately after being produced by the fine particle producing means B are adhered to the substrate A to form the powder film F, so that the surfaces are activated and easily adhere to each other. It is possible to reach the substrate A without agglomerating the produced powder C in the substrate. This is particularly effective when a small-sized raw material that easily aggregates is used.
However, since the apparatus of the present invention is provided with the compressive force imparting means D, the fine particles already adhering to the substrate are further pressed to bring the activated surfaces of the fine particles closer to make the fine particles stronger. It is also effective when laminating large-sized fine particles.
Further, for example, when using graphite which is a material having a layered structure as the raw material m, when a mechanical external force is applied to the graphite by the fine particle generating means B, flaky fine particles having an activated surface appear, which are generated. The layers reach the substrate and are sequentially stacked. However, since the fine particles have a large size and are flaky in shape, the activated surfaces of the respective fine particles cannot sufficiently approach each other. Therefore, a strong film cannot be formed simply by laminating flaky fine particles.
However, in this configuration, by pressing the laminated graphite fine particles by the pressing member D which is a compressive force applying means, the activated surfaces of the flaky fine particles are sufficiently close to each other, and the flaky fine particles Thus, a strongly bonded film is formed in a state where the directivity is maintained and the film has a uniform orientation.
As a result, a homogeneous graphite powder film can be efficiently formed on the surface of the substrate.

[Powder film forming method]
A powder film forming method using the powder film forming apparatus X of the present invention will be described below.
As shown in FIG. 4, in the powder film forming method, the raw material m is introduced into the processing container 2, the atmospheric pressure and the atmospheric gas inside the processing container 2 are adjusted, and different types of particles are added to the raw material m. Then, the friction control step of adjusting the friction coefficient of the raw material m and the pressing member 1 disposed close to the inner peripheral surface 2a of the processing container 2 are moved relative to each other, thereby applying a mechanical external force to the raw material m. a fine particle forming step for forming m into fine particles, a fine particle attaching step for attaching the fine particles immediately after the fine particle formation to the substrate A, and a compressive force applying step for applying a compressive force to the fine particles attached to the substrate A.

  Among these, if the friction coefficient of the raw material m is controlled in the friction control step, the pulverization speed of the raw material m and the characteristics of the generated powder C can be greatly varied. Therefore, it is easy to obtain a powder film having various characteristics by arbitrarily controlling the film forming process.

For example, the friction control step can be a step of changing the degree of vacuum. Specifically, a gas such as air is discharged from the inside of the processing chamber 3 by a vacuum pump (not shown).
Thus, by changing the degree of vacuum, the amount of gas such as air interposed between the raw material particles can be adjusted. By increasing the degree of vacuum, the amount of gas present between the raw material particles is reduced. As a result, the raw material particles are closer to each other and easily collide with each other, and the force is easily transmitted between them, so that the pulverization efficiency is increased. On the other hand, when the degree of vacuum is lowered, the amount of gas between the raw material particles increases, it becomes difficult to collide with each other, the force acting between the raw material particles is reduced, and the pulverization efficiency is lowered.
For example, in the case of graphite particles, the oxygen partial pressure is reduced by increasing the degree of vacuum, so that adsorption of oxygen molecules on the particle surface is reduced, and the coefficient of friction between the raw material particles can be increased. As a result, the force acting between the raw material particles is increased and the grinding efficiency is improved.
Thus, by using a simple method of changing the degree of vacuum, the size of the fine particles obtained can be changed, and the grinding efficiency can be adjusted.

The friction control step can be a step of changing the atmospheric gas. For example, when pulverizing graphite, if the atmospheric gas is oxygen, the fine particles after pulverization are likely to be flakes. When the atmospheric gas is helium, it tends to be a three-dimensional shape.
Further, it is possible to inject different gas types into the existing atmospheric gas and perform gas replacement to change the type of the atmospheric gas.

In the friction control step, different kinds of particles different from the raw material m may be added. For example, polyvinylidene fluoride (PVDF) can be used as the different particles in the case of pulverizing graphite.
In this way, by attaching or bonding particles having a component different from the fine particles around the substance serving as the core of the fine particles, the friction coefficient of the graphite as the raw material m can be easily controlled. Further, since different types of particles different from the raw material m are added, the formed powder film F can retain characteristics based on a plurality of types of materials.
The different kinds of particles can coexist with the raw material m from the beginning of the film forming process, or can be mixed with the raw material m from the middle of the film forming process.
Any of the above friction control steps may be performed according to the raw material, and is not necessarily performed.

<Other configurations>
(Raw material input means)
As shown in FIG. 1, the raw material m can be continuously supplied to the processing chamber 3 by providing the raw material charging means 90. Thereby, the desired powder film F can be manufactured continuously.

Further, after supplying a certain raw material m to generate fine particles and forming a powder film F on the surface of the substrate A, the film is formed by supplying fine particles of different raw materials or particles of the same quality but different in particle diameter. May be. Thereby, the powder film F made of a plurality of layers of different materials can be formed on the surface of the substrate A.
For example, a raw material for forming a primer film for facilitating adhesion of the produced powder C to the substrate A is charged from the raw material charging means 90 to perform fine particle formation, fine particle adhesion, and compression force application, and the primer film is applied to the substrate A. Form. Thereafter, the raw material m is charged from the raw material charging means 90, and the powder film F is laminated on the primer film by performing fine particle formation, fine particle adhesion, and compression force application. With the apparatus of the present invention, various powder films F can be obtained using various combinations of raw materials.
In addition, the raw material input means 90 can be configured to be freely withdrawn so that the raw material m can be supplied into the processing container 2, for example.

(Temperature control means)
When the produced powder C is produced by the fine particle producing means B, or when the compressive force is intermittently applied by the compressive force applying means D, the temperature of the powder film forming apparatus X rises due to frictional heat or the like. Therefore, a temperature adjusting means can be provided in order to adjust the temperature suitable for film formation.
As temperature control means, for example, a jacket (not shown) that covers the entire outer peripheral surface of the processing container 2 may be provided, and a cooling liquid may be circulated. Of course, a heating liquid may be circulated depending on the film forming conditions.

(Discharge means)
The powder film forming apparatus X may be provided with discharge means 20 for discharging the produced powder C. The discharge means 20 discharges, for example, from the treatment surface 1a as a discharge portion disposed to face the inner peripheral surface 2a to the generated powder C deposited on the inner peripheral surface 2a.
The discharging means 20 is configured so that a voltage can be applied from the power supply unit 21 to the conducting wire 22 connected to the press head 1 </ b> A insulated from the processing vessel 2 and the conducting wire 23 connected to the processing vessel 2. Thus, discharge plasma is generated by glow discharge or the like in the gap 7 between the processing surface 1a of the press head 1A and the inner peripheral surface 2a of the processing container 2. As a result, the surface of the produced powder C to which mechanical energy is applied can be activated by the gap 7 between the inner peripheral surface 2a and the treatment surface 1a.

When discharging is performed by the discharge means 20, if the inner peripheral surface 2a and the processing surface 1a are coated with the same material as the generated powder C, the inner peripheral surface 2a and the processing surface 1a are etched. Convenient to suppress contamination.
Moreover, although the discharge means 20 is the treatment surface 1a of the press head 1A, the discharge means 20 may discharge the inner peripheral surface 2a from a discharge portion different from the treatment surface 1a.

(Particle state determination means)
When performing the fine particle treatment, the raw material m may be aggregated. In such a case, an excessive torque is applied to the shaft body 11 and the motor via the press head 1A, and there is a risk that the powder may be overheated or the apparatus may be damaged. In order to prevent this, for example, it is preferable to provide a torque sensor 50 that detects a torque fluctuation of the shaft body 11. Thereby, the approximate particle diameter of the raw material m in the inside of the processing chamber 3 can be grasped. If the detection value of the torque sensor 50 is excessive, the occurrence of the agglomeration can be detected.

Further, by providing such a torque sensor, the particle state determining means 28 can be configured in the powder film forming apparatus X of the present invention.
The fine particle state determination means 28 increases the specific surface area of the produced powder C as the processing state of the raw material m to which mechanical action is applied inside the processing container 2 increases, and the processing surface 1a and the inner peripheral surface 2a Take advantage of the increased resistance in relative movement. That is, when the rotational speed of the shaft body 11 or the torque applied to the shaft body 11 exceeds a predetermined value, it can be determined that the processing state of the raw material m has reached a desired fine particle state.

(Power control means)
For example, the powder film forming apparatus X may be provided with a power control means 30 for reducing the driving speed of the rotation driving means 12 by knowing the end of the micronization process. By providing the apparatus, the atomization step and the like can be stopped at an optimal timing. As a result, the particle size distribution of the fine particles forming the powder film F becomes narrow, and a uniform powder film F can be obtained.

[Example 1]
Using the powder film forming apparatus X described above, a film formation process was performed under the following conditions to form a powder film on the substrate A. 12.0 g of graphite was used as a powder raw material. As the heterogeneous particles, 4.0 g of PVDF was used.
The operating conditions of the powder film forming apparatus X in the case where the raw material m is only graphite were the rotation speed of the press head 1A of 4000 rpm, the atmospheric pressure of 10 Pa, and the processing time of 20 minutes.
The operating conditions of the powder film forming apparatus X when PVDF was added to graphite were a press head 1A rotation speed of 4000 rpm, an atmospheric pressure of 50 Pa, and a processing time of 10 minutes.

FIG. 5 shows a photomicrograph of graphite before the micronization step. From this, it can be seen that graphite is a substance having a layered structure.
FIG. 6 shows a micrograph of a cross section of the powder film F formed by finely pulverizing graphite. Thereby, it turns out that the powder film F shows a layer shape in the cross-sectional view. That is, in the powder film forming apparatus X of the present invention, if the generated flaky fine particles immediately adhere to the surface of the substrate holding means 4, the desired powder film can be obtained even if it is a flaky particle having a relatively large size. It can be seen that F is obtained.
FIG. 7 shows a photomicrograph of the surface of the powder film F formed by converting the graphite into fine particles. Thereby, it turns out that the powder film F has a smooth surface shape.

[Example 2]
The transition of specific surface area when the friction control process was performed was examined.
FIG. 8 shows a change in the relationship between the specific surface area (m ² / g) of the produced powder C and the degree of vacuum (Pa) when the friction control step for changing the degree of vacuum is performed. The treatment was performed at 4,000 rpm for 20 minutes with respect to 9.9 g of graphite.
In FIG. 8, it can be seen that the specific surface area increases as the degree of vacuum decreases, that is, the pulverization efficiency increases as the degree of vacuum decreases.

In FIG. 9, the transition of the specific surface area was examined when the treatment time for atomization passed when the atmospheric gas was atmospheric air and the degree of vacuum was 10 Pa. The fine particle treatment was performed under the condition of 4000 rpm with respect to 9.9 g of graphite.
When the atmospheric gas is atmospheric pressure air, the specific surface area hardly changes even when the pulverization time elapses, and the pulverization efficiency does not change. However, it can be seen that when the degree of vacuum is increased to 10 Pa, the specific surface area increases as the pulverization time elapses, and the pulverization efficiency improves.

FIG. 10 shows the relationship between the specific surface area (m ² / g) of the produced powder C and the operation time (minutes) when the friction control step of adding different particles different from the raw material m is performed. The pulverization process was performed under the conditions of 4000 rpm and 50 Pa for 12.0 g of graphite and 4.0 g of PVDF.
According to this, it was found that when different kinds of particles are added, the specific surface area increases with the lapse of operation time.

[Another embodiment]
<1> In the above embodiment, an example in which graphite is used as the layered material has been shown. However, the present invention is not limited to this. For example, as an inorganic layered material, layered silicate clay (clay mineral), layered hydroxide, transition metal oxide, transition metal dichalcogenide, phosphate, metal phosphorus compound Etc. can be used.
In addition, oxide superconducting materials such as lanthanum, yttrium, bismuth, and thallium can be used.
Furthermore, it is also possible to use a layered material composed of a layered perovskite compound, a transition metal dichalcogenide, a metal halide, etc. having conductivity.

<2> The fine particles constituting the powder film F are not limited to those made of a single material, but may be a generated powder C generated by synthesizing a plurality of materials.

<3> In the said embodiment, the case where the processing container 2 was fixed and the press member 1 rotated inside the said processing container 2 was illustrated. However, it is not limited to such an embodiment, and the pressing member 1 may be fixed and the processing container 2 may rotate, or the pressing member 1 and the processing container 2 may rotate in opposite directions.

<4> Although the press head 1A provided with the single processing surface 1a is illustrated in the above embodiment, the present invention is not limited to this, and a plurality of processing surfaces 1a may be provided.

<5> In the above embodiment, the processing surface 1a of the press head 1A and the compressive force applying means D are used as a common member. However, the present invention is not limited to this, and the processing surface 1a and the compressive force applying means D may be separate members. At this time, the compressive force applying means D is configured to control the drive separately from the press head 1 </ b> A so as to apply the compressive force to the powder film F of the substrate A. The compressive force applying means D is provided at a position closer to the substrate A than the processing surface 1a which is the fine particle generating means B.
The compressive force applying means D is not limited to the rotationally driven mode, and may be configured to apply the compressive force to the powder film F of the substrate A by reciprocating driving.

<6> In the above embodiment, the configuration in which the compressive force is intermittently applied to the powder film F has been described. However, the present invention is not limited to this, and a configuration in which a compressive force is continuously applied to the powder film F may be employed.
For example, the compressive force applying means D is constituted by a roller that moves while rotating on the surface of the powder film F formed by attaching fine particles to the substrate A so as to have a predetermined thickness. At this time, the substrate A is fixed without sliding.
Further, the roller and the substrate A may be moved relative to each other in opposite directions.

<7> In the present embodiment described above, the compressive force applying means D is configured to be able to contact the substrate A. However, the present invention is not limited to this, and the compressive force may be applied to the substrate A without contacting the compressive force applying means D and the substrate A. For example, the compression force applying means D is configured to release compressed air. In this case, by discharging the compressed air toward the powder film F, characteristics such as the powder density of the powder film F can be controlled.

  Furthermore, a compressive force may be applied to the powder film F by applying a centrifugal force to the powder film F formed on the surface of the substrate A. For this purpose, for example, the pressing member 1 is fixed, the processing container 2 is rotated, and the substrate A is held on the processing container 2 side to form the powder film F. Thereby, centrifugal force acts on the powder film F formed on the substrate A by the rotation of the processing container 2. By controlling the rotation speed of the processing container 2, the centrifugal force acting on the powder film F can be adjusted, and the density and the like of the powder film F can be controlled.

<8> In the above embodiment, the case where the compression force relaxation mechanism G is configured by a spring member is illustrated. However, the present invention is not limited to this, and for example, a low-resilience elastic resin having shock absorption performance can be applied.

<9> In the above embodiment, the processing container 2 is a cylindrical member having a horizontal axis Z. However, the present invention is not limited to this, and the axis Z may be in the vertical direction.

  The powder film forming apparatus and the powder film forming method of the present invention are a film forming apparatus and a film forming method for forming a powder film by attaching fine particles generated by applying mechanical external force to a raw material to a substrate. Applicable.

Schematic cross-sectional view of the powder film forming apparatus of the present invention Schematic diagram of essential parts of the powder film forming apparatus of the present invention Schematic diagram of essential parts of the powder film forming apparatus of the present invention The flowchart which showed the outline | summary of the procedure of the powder film formation method of this invention Micrograph showing graphite before pulverization Photomicrograph showing cross section of graphite powder film Micrograph showing the surface of graphite powder film The figure which shows the relationship between the degree of vacuum and the specific surface area in the friction control process The figure which shows the relationship between the grinding operation time and the specific surface area when the atmosphere is different The figure which shows the relationship between the grinding operation time and the specific surface area when different kinds of particles are added

Explanation of symbols

X Powder film forming apparatus A Substrate B Fine particle generation means C Fine particles (generated powder)
D Compression force applying means (pressure member)
E Slide mechanism G Compression force relaxation mechanism m Raw material 1 Press member 2 Processing container 4 Substrate holding means

Claims (9)

A processing unit for containing and holding the raw material and a pressing member disposed in proximity to the inner peripheral surface of the processing container relatively move, thereby providing a mechanical external force to the raw material to make the raw material fine particles, Substrate holding means for holding a substrate to which the fine particles immediately after generated by the fine particle generating means are attached;
A powder film forming apparatus comprising compressive force applying means for applying a compressive force to the fine particles attached to the substrate.   The powder film forming apparatus according to claim 1, wherein the compressive force applying unit is a pressurizing member capable of coming into contact with the fine particle adhesion surface of the substrate.   The pressure member applies a compressive force at a preset position, and the substrate holding unit includes a slide mechanism that slides the substrate with respect to a compressive force applying position by the pressurizing member. Powder film forming equipment.   The powder film forming apparatus according to any one of claims 1 to 3, wherein the substrate holding unit includes a compression force relaxation mechanism that relaxes the compression force applied to the fine particles attached to the substrate by the compression force applying unit. A process for storing and holding the raw material and a pressing member disposed close to the inner peripheral surface of the process container are relatively moved, thereby applying a mechanical external force to the raw material to make the raw material fine,
A fine particle attaching step for attaching the fine particles immediately after the fine particles to the substrate;
A compressive force applying step of applying a compressive force to the fine particles attached to the substrate.   The powder film forming method according to claim 5, further comprising a friction control step of controlling a friction coefficient of the raw material.   The powder film forming method according to claim 6, wherein the friction control step is a step of changing a degree of vacuum.   The powder film forming method according to claim 6, wherein the friction control step is a step of changing an atmospheric gas.   The powder film forming method according to claim 6, wherein the friction control step is a step of adding different kinds of particles different from the raw material.