Powder supply device and powder deposition device using same

Abstract

A powder supply device (100) comprises: a container (110) in which powder is stored; a tubular discharge passage (131) through which the powder is discharged from the container (110); a feeding carrying unit (140) that feeds and carries the powder toward the discharge passage (131) in the container (110); a feeding driving unit (145) that drives the feeding carrying unit (140); a shaft (150) of which a tip portion (151) is inserted and retracted into / from the discharge passage (131); and an advance / retreat drive unit (155) that drives the shaft (150) forward and backward. The shaft (150) is disposed to penetrate the feeding carrying unit (140), and the powder that is pressed when the shaft (150) advances is discharged from the discharge passage (131), whereby the powder is supplied.

Description

Powder supply device and powder film forming device using the same

[0001] The present invention relates to a powder supplying device and a powder film forming device using the same.

[0002] The present applicant has provided a powder coating method and apparatus for forming a coating on dispersed powder without using a rotation or oscillation mechanism (Patent Document 1). According to Patent Document 1, a jet flow, preferably a supersonic jet flow, containing the powder to be coated is generated. At the speed of the jet flow, shock waves spread from the tip of the powder, easily and reliably separating and diffusing aggregated powder particles. The diffusion effect is particularly significant at supersonic speeds exceeding the speed of sound, which is the maximum speed of vibrations propagating through a medium. The dispersed powder is introduced into a reaction vessel. In the reaction vessel, a film is formed on the surface of the dispersed powder by a reaction between a reactive gas activated by plasma and a raw material gas.

[0003] Patent No. 7013062

[0004] However, the powder contained in the supply source, for example, a hopper, tends to aggregate, which can cause clogging during the supply of the powder from the supply source to the supply destination, resulting in a cutoff in the supply of the powder.

[0005] An object of the present invention is to provide a powder supplying device that can reliably supply powder to a destination without clogging, and a powder film forming device using the same.

[0006] (1) One aspect of the present invention relates to a powder supplying device comprising: a container for storing powder; a tubular discharge passage through which the powder is discharged from the container; a feed moving section for feeding and moving the powder within the container towards the discharge passage; a feed drive section for driving the feed moving section; a shaft disposed within the container, the tip of which is inserted into and removed from the discharge passage; and an advance / retract drive section for driving the shaft to move forward and backward, wherein the shaft is disposed to pass through the feed moving section, and when the shaft moves forward, the powder is pushed and discharged from the discharge passage, thereby supplying the powder.

[0007] According to one aspect of the present invention, powder in a container is fed and moved to a discharge passage by a feed moving unit driven by a feed drive unit. The fed powder is introduced into a tubular discharge passage when the tip of the shaft is retracted toward the container from the discharge passage by the advance / retract drive unit. The discharge passage is tubular with a narrow opening, making it prone to clogging with powder. Therefore, by moving the shaft forward using the advance / retract drive unit, the tip of the shaft pushes the powder and discharges it from the discharge passage. By positioning the feed moving unit approximately at the center of the container to ensure efficient feed movement and providing a shaft that penetrates the feed moving unit, the shaft can be moved forward and backward at the approximately center of the container without interfering with the feed moving unit. Therefore, the discharge passage can be provided on an extension of the approximately central axis of the container, allowing the powder to be efficiently discharged.

[0008] (2) In one aspect (1) of the present invention, the feed moving section may include a feed screw having a hollow section along a central axis, and the shaft may be disposed within the hollow section of the feed screw, thereby allowing the shaft to be disposed through the feed moving section.

[0009] (3) In one aspect (2) of the present invention, the container may further include an agitator provided upstream of the feed / transfer unit in the container to agitate the powder in the container, and an agitation driver that drives the agitator. In this way, the powder before being fed and transferred by the feed / transfer unit can be agitated by the agitator driven by the agitation driver. This allows agglomerated powder to be dispersed.

[0010] (4) In the aspect (3) of the present invention, the feed screw may be disposed so as to penetrate the stirring unit. In this way, the stirring unit can be disposed at a substantially central position of the container, ensuring efficient stirring. By providing a shaft that penetrates the feed moving unit and the stirring unit, the shaft can be moved back and forth at a substantially central position of the container without interfering with the feed moving unit and the stirring unit.

[0011] (5) In one aspect (4) of the present invention, the feed drive unit is a first rotary drive unit that rotates the feed screw, and the stirring drive unit is a second rotary drive unit that rotates the stirring unit, and the first and second rotary drive units can be provided outside the container. The first and second rotary drive units can rotate the feed screw and the stirring unit at the same rotational speed or at different rotational speeds. If the feed screw and the stirring unit are rotated at the same rotational speed, one rotary drive unit can be used as both the first and second rotary drive units.

[0012] (6) In the aspect (3) of the present invention, the second rotation drive unit may reversibly rotate the stirring unit. By reversibly rotating the stirring unit, the effect of stirring the powder in the container can be improved.

[0013] (7) In one aspect (3) of the present invention, the rotation speed of the feed screw can be faster than the rotation speed of the agitator. In order to increase the rotation torque of the agitator that agitates the powder, the agitator is set to a relatively low speed, while the rotation torque of the feed screw that feeds and moves the powder can be relatively small, and the rotation speed can be set according to the feed speed of the powder.

[0014] (8) Another aspect of the present invention relates to a powder film forming apparatus including: the powder supplying device according to any one of the above-described aspects (1) to (7); and a film forming device that forms a film on the powder discharged from the powder supplying device.

[0015] According to another aspect of the present invention, a film can be formed on powder that is reliably discharged from the powder supply device without clogging and supplied to the film forming device.

[0016] (9) In another aspect (8) of the present invention, the film-forming apparatus can include a jet nozzle that ejects a jet stream containing powder discharged from the powder supply device and disperses the powder, and a reaction vessel that forms a film on the dispersed powder through a reaction between a plasma-activated reactive gas and a raw material gas. This generates a jet stream, preferably a supersonic jet stream, containing the powder to be film-formed. At the speed of the jet stream, shock waves spread from the tip of the powder, easily and reliably separating and diffusing aggregated powder particles. The diffusion effect is particularly significant at supersonic speeds exceeding the speed of sound, which is the maximum speed of vibrations propagating through a medium. The dispersed powder is introduced into the reaction vessel. In the reaction vessel, a film is formed on the surface of the dispersed powder through a reaction between a plasma-activated reactive gas (e.g., activated species or ions) and the raw material gas. In particular, the discharge passage of the powder supplying device that supplies powder to the jet nozzle cannot have a large opening, so the powder is likely to become clogged. However, the powder supplying device of any of the above-mentioned aspects (1) to (7) can intermittently supply an appropriate amount of powder without clogging.

[0017] (10) In another aspect (8) of the present invention, the powder supplying device further includes a hopper for accommodating the powder, and the hopper can supply the powder to the container of the powder supplying device. In this way, the powder introduced into the hopper in large quantities can be reliably supplied to the film forming device by the powder supplying device without clogging.

[0018] (11) In another aspect (8) of the present invention, the reaction vessel may further include a powder outlet port provided in a bottom wall of the reaction vessel, a plug inserted into and removed from the powder outlet port from outside the reaction vessel, and a plug drive unit that drives the plug to insert and remove to close the powder outlet port during film formation and open the powder outlet port during discharge. The plug that closes the powder outlet port during film formation on the powder can be moved to the outside of the reaction vessel to open the powder outlet port when the coated powder is recovered, and the coated powder can be discharged from the powder outlet port.

[0019] Fig. 1 is a diagram showing a film forming apparatus according to one embodiment of the present invention. Fig. 2 is a diagram showing a powder supplying apparatus according to one embodiment of the present invention. Fig. 3 is a partially enlarged cross-sectional view of the powder supplying apparatus. Fig. 4 is a schematic cross-sectional view of the jet nozzle shown in Fig. 1. Fig. 5 is a schematic cross-sectional view of the atmospheric pressure plasma source shown in Fig. 1. Fig. 6 is a diagram showing a plug and a plug driving unit inserted into and removed from a powder outlet port.

[0020] The following disclosure provides different embodiments and examples for implementing different features of the presented subject matter. Of course, these are merely examples and are not intended to be limiting. Furthermore, the present disclosure may repeat reference numerals and / or letters in various examples. Such repetition is for the sake of brevity and clarity and does not, in itself, require a relationship between the various embodiments and / or configurations described. Furthermore, when a first element is described as being "connected" or "coupled" to a second element, such a description includes embodiments in which the first and second elements are directly connected or coupled to each other, as well as embodiments in which the first and second elements are indirectly connected or coupled to each other with one or more other intervening elements therebetween. Furthermore, when a first element is described as "moving" relative to a second element, such a description includes embodiments in which at least one of the first and second elements moves relative to the other.

[0021] 1. Film Formation Apparatus FIG. 1 shows a film formation apparatus 1 according to this embodiment. The film formation apparatus 1 includes at least one jet nozzle 10, at least one (e.g., three) atmospheric pressure plasma source 20, a reaction vessel 30, and a powder supply device 100 that supplies powder to the jet nozzle 10. The reaction vessel 30 may include at least one powder inlet port 31, at least one (e.g., three) source gas inlet port 32, at least one (e.g., three) atmospheric pressure plasma flow inlet port 33, and at least one exhaust / powder outlet port 34. In this case, the source gas inlet port 32 is connected to a source gas source 4 via a mass flow controller (MFC) 4A and a valve 4B. Here, the source gas source 4 may contain an inert carrier gas in addition to the source gas. The jet nozzle 10 includes a powder inlet port 11A and a gas inlet port 12A. The powder inlet port 11A is connected to a powder hopper 2, through which powder is introduced. The gas inlet port 12A is connected to an inert gas source 3, for example, Ar, via a flow controller (MFC) 3A and a valve 3B. The gas source 3 may also be used as a raw material gas source 4. In this case, the raw material gas inlet port 32 is unnecessary. The jet nozzle 10 ejects a two-phase jet flow (jet flow) containing a gas (inert gas or raw material gas) and dispersed powder. The atmospheric pressure plasma source 20 generates an atmospheric pressure plasma flow containing an activated reactive gas. A reactive gas source 5 is connected to the atmospheric pressure plasma source 20 via a flow controller (MFC) 5A and a valve 5B. Here, the reactive gas source 5 can contain an inert carrier gas in addition to the reactive gas.

[0022] Powder, a plasma flow from a plasma source, and a source gas are introduced into the reaction vessel 30, and a film is formed on the powder. The formed powder and gas are discharged through an exhaust / powder outlet port 34 provided, for example, at the bottom of the reaction vessel 30. While the gas inside the reaction vessel 30 is exhausted, the formed powder is stored (recovered) in a powder storage (broadly speaking, a recovery section) 7 (FIG. 5).

[0023] 2 shows the powder supply device 100. The powder supply device 100 includes a container 110 that contains powder supplied from a powder hopper 2. In this embodiment, the container 110 may include a cylindrical body 111 and a tapered tube 112 connected to the lower part of the cylindrical body 111. The upper part of the cylindrical body 111 is fixed to and supported by a base 120. The powder hopper 2 is fixed to the base 120, and the powder from the powder hopper 2 is introduced into the cylindrical body 111 through an opening in the base 120.

[0024] The lower part of the tapered tube 112 of the container 110 is fixed to a connecting part 130 that connects the powder introduction port 11A of the jet nozzle 10 to the container 110. The connecting part 130 may be integral with the container 110, or the connecting part 130 may also serve as the powder introduction port 11A of the jet nozzle 10. In this embodiment, as shown in FIGS. 2 and 3 , a tubular discharge passage 131 through which powder is discharged from the container 110 is provided in the connecting part 130. The inner diameter φA of the discharge passage 131 shown in FIG. 2 is a small diameter, for example, about 2 mm. As shown in FIG. 3 , the connecting part 130 has a communication hole 132 that connects the lower end opening 113 of the tapered tube 112 to the discharge passage 131.

[0025] The powder supplying device 100 includes a feed moving unit 140 that feeds and moves the powder in the container 110 toward the discharge passage 131. The feed moving unit 140 may include, for example, a feed screw 141 and a cylindrical member 142 that surrounds at least the lower end of the feed screw 141. The feed screw 141 has a thread, such as a trapezoidal thread, with an outer diameter of φB as shown in FIG. 2. When the feed screw 141 is rotated, the powder restricted by the cylindrical member 142 is fed and moved along the thread. Note that the cylindrical member 142 is not essential, and the lower end opening 113 provided in the tapered tube 112 or the communication hole 132 provided in the connecting portion 130 may be used instead.

[0026] The powder supplying device 100 has a feed drive unit 145 that drives the feed movement unit 140. The feed drive unit 145 has, for example, as a first rotation drive unit, a pulley 146 that rotates integrally with the feed screw 141, and a drive source such as a belt and a motor that rotates the pulley 146.

[0027] Powder supplying device 100 is disposed within container 110 and includes a shaft 150 including a tip 151 that is inserted into and removed from discharge passage 131, and an advance / retract drive unit 155 that drives shaft 150 forward and backward. When shaft 150 advances and enters discharge passage 131, the powder is pushed by shaft 150 and discharged from discharge passage 131. Advance / retract drive unit 155 reciprocates shaft 150 using fluid pressure such as air or oil, or one of the advance / retract drives may be substituted by the biasing force of a biasing member such as a spring.

[0028] In this embodiment, the shaft 150 is disposed through the feed moving portion 140 so that the feed moving portion 140 and the shaft 150 are disposed approximately at the center of the container 110. To this end, for example, the feed screw 141 has a hollow portion 141A along its central axis, and the shaft 150 is disposed within the hollow portion 141A of the feed screw 141.

[0029] According to this embodiment, the powder in the container 110 is fed and moved to the discharge passage 131 by the feed moving unit 140 driven by the feed driving unit 145. The fed powder is introduced into the tubular discharge passage 131 when the forward / backward driving unit 155 moves the tip 151 of the shaft 150 back toward the container 110 from the discharge passage 131. The discharge passage 131 is tubular and has a narrow opening, so it is prone to clogging with powder. Therefore, by moving the shaft 150 forward using the forward / backward driving unit 155, the tip 151 of the shaft 150 pushes the powder and discharges it from the discharge passage 131. By arranging the feed moving unit 140 at a substantially central position of the container 110 to ensure efficient feed movement and providing the shaft 150 penetrating the feed moving unit 140, the shaft 150 can be moved forward and backward at a substantially central position of the container 110 without interfering with the feed moving unit 140. Therefore, the discharge passage 131 can be provided on an extension line of the approximate central axis of the container 110, and the powder can be discharged efficiently.

[0030] In this embodiment, the container 110 may further include an agitator 160 located upstream of the feed / transfer unit 140 within the container 110 and configured to agitate the powder within the container 110, and an agitator driver 165 configured to drive the agitator 160. In this manner, the powder before being fed and transferred by the feed / transfer unit 140 can be agitated by the agitator 160 driven by the agitator driver 165. This allows agglomerated powder to be dispersed. The agitator 160 may include a rotor 161 disposed within the container 110, having an outer surface similar to the inner surfaces of the cylindrical body 111 and the tapered tube 112 and a hollow portion 162. The rotation of the rotor 161 disperses the powder within the container 110. To enhance the agitation effect, an agitator blade (not shown) may be provided attached to a hole 161A formed in the rotor 161. If an agitator blade is not used, the hole 161A may be sealed.

[0031] A lid 163 is provided to close the hollow portion 162 of the rotating body 161, and the lid 163 is fixed to a rotating shaft 164. The rotating shaft 164 is rotatably supported by a bearing 121 provided on the base 120. The rotating shaft 164 may have a bearing 164A for the feed screw 141. The stirring drive unit 165 has, as a second rotation drive unit, for example, a pulley 166 that rotates integrally with the rotating shaft 164, and a drive source such as a belt and a motor that rotates the pulley 166.

[0032] As shown in FIG. 3 , a portion of the cylindrical member 142 may be fixed to the rotor 161 within the hollow portion 162 of the rotor 161. Since the hollow portion 162 of the rotor 161 is closed by a lid 163, a flow path for the powder stirred by the stirring unit 160 is formed along the direction F4 between the inner surface of the container 110 and the outer surface of the rotor 161, as shown in FIG. 3 . In this case, the powder must pass through the cylindrical member 142, be fed axially by the feed screw 141 inside the cylindrical member 142, and be moved in the direction F5 in FIG. 3 . For this purpose, the cylindrical member 142 has an opening that allows the powder to pass through, and may be formed, for example, by a plurality of shaft-shaped members arranged with gaps in the circumferential direction, a porous member, a mesh member, or the like.

[0033] In this embodiment, the feed screw 141 is disposed so as to pass through the hollow portion 162 of the stirring unit 160. In this way, the stirring unit 160 can be disposed at a substantially central position of the container 110, ensuring efficient stirring. By providing the shaft 150 so as to pass through the feed moving unit 140 and the stirring unit 160, the shaft 150 can be moved back and forth at a substantially central position of the container 110 without interfering with the feed moving unit 140 and the stirring unit 160.

[0034] In this embodiment, a first rotational drive unit 145 that rotates the feed screw 141 of the feed moving unit 140 and a second rotational drive unit 165 that rotates the agitating unit 160 can be provided outside the container 110. The first and second rotational drive units 145, 165 can rotate the feed screw 141 and the agitating unit 160 at the same rotational speed or at different rotational speeds. If the feed screw 141 and the agitating unit 160 are rotated at the same rotational speed, one rotational drive unit may be used as both the first and second rotational drive units 145, 165.

[0035] In the present embodiment, the second rotation drive unit 165 may reversibly rotate the stirring unit 160. By reversibly rotating the stirring unit 160, the stirring effect of the powder in the container 110 can be improved.

[0036] In this embodiment, the rotation speed of the feed screw 141 can be made faster than the rotation speed of the agitator 160. To increase the rotation torque of the agitator 160 that agitates the powder, the agitator 160 is set to a relatively low speed, for example, several tens of rpm, while the rotation torque of the feed screw 141 that feeds and moves the powder can be relatively small, and the rotation speed can be made faster than the rotation speed of the agitator 160 depending on the feed speed of the powder.

[0037] 3. Jet Nozzle Fig. 4 is a schematic cross-sectional view of the jet nozzle 10 shown in Fig. 1. The jet nozzle 10 generates a supersonic jet flow F1 containing powder and a reactive gas, and ejects a two-phase jet flow F2 in which the powder is dispersed at supersonic speed.

[0038] 4 , the jet nozzle 10 may include, for example, a powder nozzle 11, a gas nozzle 12, and a mixing conduit 13. The powder nozzle 11 includes a powder inlet port 11A at its upstream end in the first direction A and a powder outlet port 11B at its downstream end. The gas nozzle 12 is provided, for example, around the powder nozzle 11, and a gas passage is formed between the inner wall of the gas nozzle 12 and the outer wall of the powder nozzle 11. The gas nozzle 12 includes, for example, a gas inlet port 12A in its peripheral wall and a gas outlet port 12B at its downstream end in the first direction A. The diameter of the peripheral wall of the gas outlet port 12B decreases as it moves downstream in the first direction A.

[0039] In this embodiment, as shown in FIG. 1 , gas is pressure-fed from, for example, an inert gas source 3 into the gas nozzle 12 via a flow rate controller 3A, a valve 3B, and a gas inlet port 12A. This gas is made supersonic by passing through a gas outlet port 12B with a reduced diameter. When the gas is ejected from the gas outlet port 12B, a negative pressure is created inside the powder nozzle 11. In the powder supply device 100, the shaft 150 is intermittently driven back and forth to sequentially supply an appropriate amount of powder. For example, the gas is pressure-fed into the gas nozzle 12 in accordance with the timing of powder supply. As a result, the powder is sucked from the powder supply device 100 through the powder inlet port 11A into the powder nozzle 11 under negative pressure.

[0040] In the mixing conduit 13 where the powder and the supersonic gas are mixed, a two-phase supersonic jet flow F1 containing the powder (solid phase) and the gas (vapor phase) is generated. In the mixing conduit 13, shock waves spread from the tip of the powder that is moving at supersonic speed, so that the condensed powder particles are easily and reliably separated and diffused. Note that, for example, the injector disclosed in Japanese Patent Laid-Open Publication No. 10-85634 ejects a two-phase supersonic jet flow containing a liquid phase and a gas phase, but does not eject a two-phase supersonic jet flow containing a solid phase (powder) and a gas phase (e.g., an inert gas).

[0041] In this embodiment, the jet nozzle 10 may have a diffuser 14 at the downstream end of the mixing pipe 13, the diameter of which increases downstream in the first direction A. The diffuser 14 can convert velocity energy into discharge pressure. At this time, the cavitation phenomenon occurring in the diffuser 14 can promote the diffusion of the powder. However, the jet nozzle 10 may not have the diffuser 14 and may eject a two-phase jet flow F2 as the supersonic jet flow F1.

[0042] In this way, a two-phase jet F2 containing powder dispersed at supersonic speed can be ejected from the mixing conduit 13 or the diffuser 14 of the jet nozzle 10. In other words, a two-phase jet F2 containing dispersed powder and a gas that functions as a carrier gas can be generated without using a rotation or swing mechanism.

[0043] 4. Plasma Source Figure 5 is a schematic cross-sectional view of the atmospheric pressure plasma source 20 shown in Figure 1. The atmospheric pressure plasma source 20 includes, for example, a grounded outer tube 21 and a high-voltage electrode 22 disposed within the outer tube 21. A high-voltage AC power supply 23 is connected to the high-voltage electrode 22. The inner surface of the outer tube 21 and the outer surface of the high-voltage electrode 22 are coated with a dielectric. Cooling water may be supplied to the water passage 21A provided in the outer tube 21 and the water passage 22A provided in the high-voltage electrode 22. A reactive gas source 5 is connected to the reactive gas inlet port 20A of the outer tube 21 via a mass flow controller (MFC) 5A and a valve 5B. The atmospheric pressure plasma flow outlet port 20B of the outer tube 21 is connected to the atmospheric pressure plasma flow inlet port 33 of the reaction vessel 30. A high-voltage electric field is formed between the outer tube 21 and the high-voltage electrode 22. When a reactive gas is introduced from the reactive gas source 5, the reactive gas is ionized to generate an atmospheric pressure plasma flow F3. The inner surface of the outer tube 21 and the outer surface of the high-voltage electrode 22 are covered with a dielectric material.

[0044] 5. Reaction Vessel A two-phase jet F2 containing powder, an atmospheric pressure plasma flow F3, and a source gas are introduced into the reaction vessel 30. Activated reactive gas (ions, activated species, etc.) in the atmospheric pressure plasma flow F3 reacts with the source gas. This reaction can form a film on the surface of the powder dispersed in the atmospheric pressure plasma flow F3. As described above, the two-phase jet F2 may be a two-phase jet containing powder and a source gas. In this case, there is no need to separately introduce a source gas into the reaction vessel 30.

[0045] Here, the reaction vessel 30 may include a peripheral wall 30A having a circular cross section in a plan view. The jet nozzle 10, the source gas source 4, and the atmospheric-pressure plasma source 20 can respectively introduce the two-phase jet F2, the source gas, and the atmospheric-pressure plasma flow F3 from a direction intersecting the radial direction of the reaction vessel 30 at a constant angle. In other words, the powder inlet port 31, the source gas inlet port 32, and the atmospheric-pressure plasma flow inlet port 33 provided in the reaction vessel 30 are formed along a direction intersecting the radial direction of the reaction vessel 30 at a constant angle. The two-phase jet F2, the source gas, and the atmospheric-pressure plasma flow F3 are introduced into the reaction vessel 30 at a predetermined pressure, for example, 0.2 Pa or higher. In this manner, as shown by the dashed lines in FIG. 5 , the dispersed powder, the source gas, and the reactive gas activated by the atmospheric-pressure plasma each form a swirling flow swirling along the peripheral wall 30A within the reaction vessel 30. As a result, the reaction between the source gas and the reactive gas and the film formation on the powder are efficiently carried out in the swirling flow.

[0046] The reaction vessel 30 can be evacuated during film formation. An exhaust port (not shown) provided in the reaction vessel 40 can be provided, for example, at the top of the reaction vessel 30 and connected to an exhaust pump (not shown). Since the two-phase jet F2, source gas, and atmospheric pressure plasma flow F3 are introduced into the reaction vessel 30 at a pressure of, for example, 0.2 Pa or more, the exhaust gas inside the reaction vessel 30 can be evacuated even without an exhaust pump 6. In this manner, the atmospheric pressure plasma flow F3 and source gas are continuously introduced into the reaction vessel 30, and a film can be formed on the powder continuously supplied to the reaction vessel 30. After film formation, the powder falls onto the bottom wall 30B of the reaction vessel 30 by its own weight.

[0047] 6, the powder discharge port 34 for the powder, which is provided, for example, in the center of the bottom wall 30B of the reaction vessel 30, is communicated with a powder discharge block 35, which is a hollow below the powder discharge port 34. The powder discharge block 35 is connected to a recovery unit (not shown).

[0048] 6, the reaction vessel 30 may further include a plug 36 that is inserted into and removed from the powder discharge port 34 from outside the reaction vessel 30, and a plug drive unit 37. The plug drive unit 37 includes, for example, a cylinder 37A and a piston rod 37B, and the plug 36 is fixed to the free end of the piston rod 37B. In this way, the plug 36 that closes the powder discharge port 34 when a film is formed on the powder can be moved to the outside of the reaction vessel 30 by the plug drive unit 37 to open the powder discharge port 34 and discharge the powder from the powder discharge port 34 when the formed powder is recovered.

[0049] The powder on which the film has been formed can be supplied again from the powder hopper 2 to the reaction vessel 30 via the powder supply device 100, thereby allowing the film forming process to be carried out multiple times on the powder.

[0050] By repeating the film formation process of the same film type on the powder, it is possible to form thicker films. On the other hand, different films can also be laminated on the powder. In this case, for example, different source gases can be stored in the source gas sources 4 connected to the multiple, e.g., three, source gas inlet ports 32 shown in FIG. 1 , and / or different reactive gases can be stored in the multiple reactive gas sources 5. Different films can be laminated on the powder by changing the source gas and / or reactive gas supplied for one or more film formation processes.

[0051] 5. Film Formation on Powder By selecting the reaction gas and raw material gas, various films can be formed on the powder. For example, an oxide film can be formed on the powder. In this case, an oxidizing gas is used as the reaction gas. The oxidizing gas can be a mixture of a carrier gas, for example, argon (Ar), and water vapor. When this mixture gas is supplied to the atmospheric pressure plasma source 20, Ar+H ２ O → Ar ＊ +OH ＊ +H ＊and the OH radical (OH ＊ On the other hand, as a raw material gas, for example, TMA(Al(CH ３ ) ３ ) is supplied using, for example, Ar as a carrier gas. ３ ) ３ ) is an OH radical (OH ＊ ) to form aluminum oxide, Al ２ O ３ As a result, the surface of the powder is covered with an oxide film.

[0052] A nitride film can be formed on the powder. In this case, nitriding gas NH ３ Nitriding gas NH ３ is supplied to the atmospheric pressure plasma source 20, NH radicals are generated. On the other hand, when the source gas is, for example, TDMAS(SiH[N(CH ３ ) ２ ] ３ ) can be used to form a SiN film on the powder by the reaction of NH radicals with TDMAS. Alternatively, for example, TDMAT(Ti[N(CH ３ ) ２ ] ４ ) is used, a TiN film can be formed on the powder by the reaction between NH radicals and TDMAT.

[0053] A metal film can be formed on the powder. In this case, for example, a halogen gas can be used as the reactive gas. When halogen is supplied to the atmospheric pressure plasma source 20, for example, Cl radicals are generated. On the other hand, when sublimated CuCl is used as the raw material gas, for example, CuCl+Cl→Cu+Cl ２ By the reaction above, a copper (Cu) film can be formed on the powder.

[0054] The reactive gas may be activated in the reaction vessel 30. The atmospheric pressure plasma is not limited to one using a high voltage electric field, and may also use, for example, high frequency waves or microwaves.

[0055] 1...film formation apparatus, 2...powder hopper, 3...inert gas source, 4...raw material gas source, 5...reactive gas source, 6...exhaust pump, 7...powder storage, 10...injector, 11...powder nozzle, 11A...powder introduction port, 11B...powder outlet port, 12...reactive gas nozzle, 11A...reactive gas introduction port, 11B...reactive gas outlet port, 13...mixing conduit, 14...diffuser, 20...atmospheric pressure plasma source, 20A...reactive gas introduction port, 20B...atmospheric pressure plasma flow outlet port, 21...outer tube, 21A...water channel, 22...high voltage electrode, 22A...water channel, 23...AC power supply, 30...reaction vessel, 30A...peripheral wall, 30B...bottom wall, 31...powder introduction port, 32...raw material Gas introduction port, 33...atmospheric pressure plasma flow introduction port, 34...powder discharge port, 36...plug, 37...plug drive unit, 100...powder supply device, 110...container, 120...base, 130...connection unit, 131...discharge passage, 140...feed movement unit, 141...feed screw, 141A...hollow portion, 142...cylindrical member, 145...feed drive unit (first rotation drive unit), 146...pulley, 150...shaft, 152...tip portion, 160...stirring unit, 161...rotating body, 162...hollow portion, 163...lid body, 164...rotating shaft, 164A...bearing, 165...stirring drive unit (second rotation drive unit), 166...pulley, F1...supersonic jet flow, F2...two-layer jet flow, F3...plasma flow

Claims

1. A powder supplying device comprising: a container for storing powder; a tubular discharge passage through which the powder is discharged from said container; a feed movement section for feeding and moving the powder within said container towards the discharge passage; a feed drive section for driving said feed movement section; a shaft disposed within said container and having a tip section which is inserted into and removed from said discharge passage; and an advance / retract drive section for driving said shaft forward and backward, said shaft being disposed so as to pass through said feed movement section, and said powder being pushed when said shaft moves forward is discharged from said discharge passage, thereby supplying said powder.

2. A powder supplying device according to claim 1, wherein the feed moving section includes a feed screw having a hollow section along a central axis, and the shaft is disposed within the hollow section of the feed screw.

3. A powder supplying device according to claim 2, further comprising: a stirring section provided within the container upstream of the feed moving section for stirring the powder within the container; and a stirring drive section for driving the stirring section.

4. A powder supplying device according to claim 3, wherein the feed screw is disposed so as to penetrate through the stirring section.

5. A powder supplying device as claimed in claim 3, wherein the feed drive unit is a first rotary drive unit that rotates the feed screw, the agitator drive unit is a second rotary drive unit that rotates the agitator, and the first and second rotary drive units are provided outside the container.

6. A powder supplying device according to claim 5, wherein the second rotation drive unit reversibly rotates the stirring unit.

7. A powder supplying device according to claim 5, wherein the rotation speed of the feed screw is faster than the rotation speed of the stirring portion.

8. A powder film forming apparatus comprising: a powder supplying apparatus according to any one of claims 1 to 7; and a film forming apparatus for forming a film on the powder discharged from the powder supplying apparatus.

9. A powder film forming apparatus according to claim 8, comprising: a jet nozzle for ejecting a jet flow containing powder discharged from the powder supply device to diffuse the powder; and a reaction vessel for forming a film on the diffused powder by a reaction between a raw material gas and a reactive gas activated by plasma.

10. A powder deposition apparatus according to claim 8, further comprising a hopper in which the powder is accommodated, the hopper supplying the powder to the container of the powder supply device.

11. A powder coating apparatus according to claim 8, wherein the reaction vessel further comprises: a powder discharge port provided in a bottom wall of the reaction vessel; a plug that is inserted into and removed from the powder discharge port from outside the reaction vessel; and a plug drive unit that drives the plug to be inserted and removed to close the powder discharge port during film formation and to open the powder discharge port during discharge.

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