JP2014159623A - Coating device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for coating an entire surface of a fine particle.SOLUTION: A coating device 1 has: a vacuum container 5; a cylindrical container 10 rotating or swinging relative to the vacuum container 5 around a center axis 9 extending in a horizontal axis direction in the vacuum container 5; an agitation bar 20 extending in the center axis direction along an inner face 19 of the cylindrical container 10, and rotating or swinging relative to the vacuum container 5 around the center axis 9 independently from the cylindrical container 10 so as to agitate powder 3 in the cylindrical container 10; and a dry process unit 30 provided in the cylindrical container 10 and emitting a coating raw material.

Description

  The present invention relates to a coating apparatus and method for coating fine particles.

  Patent Document 1 describes providing a polygonal barrel sputtering apparatus, a carbon-supported catalyst, and a method for producing the same that can support a large number of catalyst fine particles on the outer surface of a carbon support. The polygonal barrel sputtering apparatus of Patent Document 1 includes a vacuum container having a polygonal internal shape in a cross section substantially parallel to the direction of gravity, and a secondary structure formed by agglomerating primary particles of a carbon carrier placed in the vacuum container. Dispersion members that disperse the secondary particles into primary particles or secondary particles smaller than the original secondary particles, a rotation mechanism that rotates the vacuum vessel about the direction substantially perpendicular to the cross section, and a vacuum mechanism disposed in the vacuum vessel The sputtering target and rotating the vacuum vessel using a rotating mechanism or pendulum operation to disperse the carbon carrier secondary particles by the dispersing member while stirring or rotating the carbon carrier in the vacuum vessel. It is described that a fine particle or a thin film is supported on the surface of a carbon carrier by performing sputtering.

JP 2008-38218 A

  The use of core-shell type fine particles, for example, micron-level, sub-micron-level or nano-level particles, in which the surface of fine particles is coated with a material having another property or function has been started in various industrial fields. Particles at the micron level and below are easy to aggregate, and it is necessary to disperse the fine particles in order to coat the entire surface of each particle. However, for this purpose, rotating the vacuum vessel itself or pendulum movement tends to be complicated in configuration, and cannot be said to be an apparatus configuration suitable for mass production.

  One embodiment of the present invention includes a vacuum vessel, a cylindrical vessel that rotates or swings with respect to the vacuum vessel around a central axis extending in the horizontal axis direction in the vacuum vessel, and a central axis along the inner surface of the cylindrical vessel A stirring bar extending in a direction, rotating or swinging with respect to the vacuum container around a central axis independently of the container, and stirring the powder (fine particles) in the cylindrical container; A coating apparatus having a dry process unit installed in a container and discharging a coating material.

  In this coating apparatus, a cylindrical container having both ends or one end opened is disposed inside the vacuum container, and the cylindrical container, not the vacuum container itself, is rotated or swung relative to the vacuum container. Therefore, since the vacuum vessel can be fixed, the configuration of the apparatus can be easily simplified, and an apparatus suitable for mass production can be provided. Furthermore, an agitation bar extending in the central axis direction along the inner wall of the cylindrical container is installed inside the cylindrical container, and the agitation bar is rotated or swung independently of the cylindrical container and the vacuum container. Thereby, the surface of each powder (fine particles) can be coated by a dry process in a state where the powder stored in the cylindrical container is further efficiently stirred and dispersed.

  The coating apparatus is a plurality of drive shafts that support the lower half of the cylindrical container inside the vacuum container, extends along the outside of the cylindrical container, and is spaced apart in a direction perpendicular to the central axis. It is desirable to have a plurality of drive shafts arranged. It is also possible to suspend a cylindrical container in a vacuum container or to support it through a bearing or the like. By providing a plurality of drive shafts and supporting them with the lower half (lower side), the drive shaft can be used as a support member, and the cylindrical container rotates or swings inside the vacuum container with a simple configuration. The configuration can be realized.

  A typical dry process unit is a sputtering unit, and the coating apparatus switches and supplies a first AC power to the sputtering unit and a second AC power in which a DC component is superimposed on the first AC power. It is desirable to have a supply unit. By using AC power for sputtering, an insulating coating material can be used for coating. Furthermore, after the plasma is formed by the first AC power, the self-bias can be enhanced by superimposing the negative DC component, and the sputtering efficiency can be improved.

  More preferably, the sputtering unit is a non-equilibrium magnetic field sputtering unit. The density of the plasma in the closed magnetic field can be increased to expand in the direction of the powder that is the coating target, and the sputtering efficiency can be further improved.

  It is desirable to include an opening at at least one end of a cylindrical container holding the powder. The powder can be taken in and out easily. Further, the dry process unit can be supported on the vacuum container side by the support member through the opening. By fixing the dry process unit to the vacuum vessel, the dry process unit can be rotated or oscillated relative to the cylindrical vessel that rotates or oscillates. For this reason, it is easy to relatively average the coating conditions for the fine particles dispersed inside the cylindrical container, and it is easy to mass-produce products (powder) having a more stable coating quality including the film thickness of each fine particle. A coating apparatus can be provided.

  It is desirable that the coating apparatus further has a convex cap portion that covers the upper portion of the dry process unit. An example of the cap portion includes a ridge line extending along the central axis direction and a downwardly inclined surface formed on both sides of the ridge line. When the dry process unit includes a sputtering unit, the cap unit may have a shielding function. By providing a convex cap on the top, powder dispersed in a cylindrical container is less likely to be deposited above the dry process unit, improving coating efficiency, stable quality, and high yield products. Can be provided.

  Moreover, it is desirable that the cylindrical container includes a portion whose inner diameter is smaller than the diameter on the center side. It is possible to suppress the powder from diffusing from the central side where the dry process state, for example, the plasma state of sputtering is more stable toward both end sides, and to improve the coating efficiency.

  The stirring bar is in non-contact with the inner surface of the cylindrical container, and the coating apparatus is a stirring member that is directly or indirectly driven by the stirring bar, at least a part of which contacts the inner surface of the cylindrical container. It is desirable to have a stirring member. By making the stirring bar non-contact with the inner surface of the cylindrical container, the stirring bar can be easily driven independently of the cylindrical container. On the other hand, by providing a stirring member that is directly or indirectly driven by a stirring bar and at least a part of which is in contact with the inner surface of the cylindrical container, the powder in the cylindrical container is more efficiently obtained. Can be distributed. The stirring member is a member having a sufficiently large diameter (effective size) with respect to the fine particles contained in the powder, such as a chain connected to the stirring bar or a ball moved by the stirring bar.

Another aspect of the present invention is a method for producing a powder composed of fine particles coated on a surface using a coating apparatus. The coating apparatus includes a vacuum container, a cylindrical container rotatably supported around a central axis extending in the horizontal axis direction in the vacuum container, and an agitation extending in the central axis direction along the inner surface of the cylindrical container It has a bar and a dry process unit that is installed in a cylindrical container and discharges the coating material. The method includes the following steps.
・ Powder is put in a cylindrical container, and the cylindrical container is rotated or swinged around the central axis with respect to the vacuum container, and the stirring bar is rotated around the central axis independently of the operation of the cylindrical container. Rotate or swing with respect to the vacuum vessel.
• Release the coating material from the dry process unit in parallel with rotation or peristalsis.

The schematic diagram which shows the outline | summary of a coating apparatus. Sectional drawing which shows schematic structure of the center vicinity of a coating apparatus. The figure which shows typically the coated microparticles | fine-particles. The schematic diagram which shows the example from which a coating apparatus differs. The figure which shows an example of a stirring member

  FIG. 1 schematically shows a schematic structure of the coating apparatus. FIG. 2 shows a schematic structure in the vicinity of the center of the coating apparatus 1 by a cross-sectional view seen from the II-II direction of FIG. The coating apparatus 1 includes various fine particles (microparticles, submicron particles, nanoparticles, fine powders, powders, coarse powders, etc.) 2 contained in the powder 3 such as metals, ceramics, and plastics. This is a device for coating the surface of the metal with a metal, oxide, resin or the like. The coated fine particles 2 and the powder 3 containing the fine particles are used for various applications. Examples of applications are automobile exhaust gas catalysts, fuel cell catalysts, conductive fillers, sintered magnets, metal powder injection molding, electrodes, and the like. In recent years, in addition to applications aimed at saving resources, the effects of microscopic structures such as micron structures or nanostructures have also been found, including applications for such effects and applications as highly functional materials. It is.

  The coating apparatus 1 includes a vacuum vessel (chamber) 5, a cylindrical vessel (drum) 10 that rotates or swings around a central axis 9 that extends in the horizontal axis direction in the vacuum vessel 5, and an inner surface 19 of the drum 10. A stirring bar (swing arm) 20 extending in the direction of the central axis 9 along with, a sputtering unit (dry process unit) 30 installed in the drum 10, a power supply unit 50 for supplying power to the sputtering unit 30, and a drum 10, a drive unit 65 that drives the stirring bar 20, and a control unit 69 that controls these drive units 60 and 65.

  The vacuum vessel 5 includes a cylindrical main body 6 and end plates (end walls) 7a and 7b attached to flanges 6a and 6b at both ends of the main body 6 through a sealing material such as an O-ring. A drive shaft 62a for driving the drum 10 and a drive shaft 67 for driving the swing arm 20 are attached to one end plate (the left end plate in the drawing) 7a through an appropriate seal structure. It has been. The sputtering unit 30 is attached to the other end plate (the right end plate in the drawing) 7 b by a support arm 70. The support arm 70 is attached so as to penetrate the right end plate 7 b by an appropriate seal structure and support structure 71, and the sputtering unit 30 and the power supply unit 50 are connected by a wiring 59 arranged inside the support arm 70. Yes.

  The vacuum vessel 5 includes a nozzle (flange, port) 8 a connected to the vacuum generation device 81 and a nozzle 8 b connected to the gas supply device 82. The vacuum generating device 81 includes equipment for making the inside of the vacuum vessel 5 an appropriate vacuum (negative pressure) such as a rotary pump and a diffusion pump. The gas supply device 82 includes a device that supplies an appropriate gas such as Ar serving as a carrier gas for sputtering to the vacuum vessel 5. A heating mechanism 83 such as a sheathed heater arranged so as to surround the drum 10 is further arranged inside the vacuum vessel 5. The inside of the drum 10 can be indirectly heated by the heating mechanism 83 to promote degassing, or the fine particles 2 can be annealed at an appropriate timing when the fine particles 2 are coated. For example, the heating mechanism 83 is preferably capable of heating the inside of the drum 10 to at least about 200 ° C.

  The drum 10 includes a cylindrical body 11 disposed concentrically along a central axis 9 common to the cylindrical vacuum container 5 inside the vacuum container 5, and respective edges (ends) of the body 11. And side plates 12a and 12b attached to 11a and 11b. One side plate (left side plate) 12a is basically a wall plate that closes (seals) one edge 11a, and a drive shaft 67 that drives the swing arm 20 passes through the center along the central axis 9. doing. The other side plate (right side plate) 12b is basically a side plate that forms an opening and reinforces the other edge 11b of the drum 10. Accordingly, an opening 13 having a diameter substantially the same as the inner diameter of the drum 10 is formed at the center of the side plate 12b. The sputtering unit 30 is supported inside the drum portion 11 of the drum 10 by the support arm 70 extending through the opening 13 in a state independent of the drum portion 11.

  The drum 10 includes conical tapered portions 16a and 16b disposed on both edges 11a and 11b side of the inner side (inner surface) 19 of the body portion 11. The taper portions 16 a and 16 b are arranged such that the inner diameters of the tapered portions 16 a and 16 b are narrower on the both edges 11 a and 11 b side (both ends) than the center portion of the body portion 11. Therefore, the structure of the inside of the body 11, that is, the substantial inside (inner surface) 19 of the drum 10 has a so-called barrel shape in which the center (center side) is wide and both ends are narrow. For this reason, it is suppressed that the powder 3 held inside the drum 10 is dispersed or diffused in the direction of both ends 11a and 11b of the drum 10.

  The drum 10 further includes a rotor 14 connected to the outside of the left side plate 12a, and a passive gear (external gear) 15 attached to the substantially central outer peripheral surface of the drum 10. The drive unit 60 for driving the drum 10 is connected to the motor 61 by a shaft 61a that is driven by the motor 61, penetrates the end wall 7a of the vacuum vessel, and the shaft 62a and the train wheel 62c, and extends along the outside of the drum 10. Shaft 62b. A drive pulley 63 that contacts the rotor 14 and a drive gear 64 that meshes with the passive gear 15 are attached to the shaft 62b. Therefore, the drum 10 is placed in the left or right (clockwise or counterclockwise) direction around the central axis 9 with respect to the vacuum vessel 5 inside the vacuum vessel 5 by the driving unit 60 disposed outside the vacuum vessel 5. Can also be rotated or perturbed.

  In FIG. 1, one shaft 62 b is shown at a position where it can be seen with respect to the drum 10 so that the relationship between the drive unit 60 and the drum 10 can be easily understood. However, the coating apparatus 1 extends along the outside of the drum 10. A plurality of shafts 62b extending in parallel, and these shafts 62b are connected to the shaft 62a by a train wheel 62c.

  As shown in FIG. 2, as an example, the coating apparatus 1 includes two pieces arranged along the central axis 9 with appropriate intervals at left and right symmetrical positions in a direction (left and right) perpendicular to the central axis 9. The lower side (lower half) of the drum 10 is rotatably supported with respect to the vacuum vessel 5 inside the vacuum vessel 5 by these shafts 62b. In this example, the drum 10 rotates (swings) and is supported by the shaft 62b via the rotor 14 and the passive gear 15. Instead of the rotor 14 and the passive gear 15, two sets of passive gears may be provided, two sets of rotors 14 may be provided, or a mechanism for transmitting other driving force may be employed. The drum 10 may be supported by three or more shafts 62b, and the shaft that supports the drum 10 may include a shaft that rotates but does not transmit power.

  It is also possible to suspend the drum 10 inside the vacuum vessel 5 or to rotatably support the drum 10 using a bearing. In this example, a plurality of drive shafts 62b are provided, and the drive shaft 62b can be used as a support member by supporting the lower half (lower side) of the drum 10 by them. Thus, a configuration in which the drum 10 rotates or swings can be realized.

  A stirring bar (swing arm) 20 disposed inside the drum 10 connects the swing portion 21 that is curved or bent along the inner surface 19 of the barrel-shaped drum 10, and the swing portion 21 and the drive shaft 67. Arm portion 29 to be included. Although the cross-sectional shape of the swing part 21 may be a bar, a square, or the like, one shape suitable for stirring is a V-shape. As shown in FIG. 2, the swing portion 21 of this example has an inverted V-shaped cross section, and the V-shaped end portions 22 and 23 are not in contact with the inner surface 19 but are arranged so as to be very close to each other. Has been. The cross-sectional shape of the swing portion 21 is not limited to the V shape, and can be selected from a triangle, a quadrangle, a circle, a ring shape, and the like in consideration of the material of the powder 3, the particle size, the degree of aggregation, and the like.

  The drive unit 65 that drives the stirring bar 20 includes a motor 66 and a drive shaft 67 that is driven by the motor 66. A drive shaft 67 passes through the end wall 7 a of the vacuum vessel and the side plate 12 a of the drum 10 along the central axis 9, and is connected to the arm portion 29 inside the drum 10. Therefore, the stirring bar 20 is moved left and right (clockwise, counterclockwise) around the central axis 9 with respect to the vacuum vessel 5 and the drum 10 inside the drum 10 by the drive unit 65 disposed outside the vacuum vessel 5. Can rotate or swing in any direction.

  In addition, by appropriately controlling the drive units 60 and 65 by the control unit 69, the drum 10 and the stirring bar 20 can be synchronized and rotated in the same direction or in opposite directions. is there. The control unit 69 includes appropriate computer resources such as a CPU and a memory, and can freely control the drive units 60 and 65 by software (program, program product).

  The sputtering unit 30 is an example of a dry process unit that coats the surfaces of the fine particles 2 contained in the powder 3 by a dry process. The dry process unit may discharge the coating material into the drum 10 by another dry process such as arc vapor deposition.

  The sputtering unit 30 includes a cathode unit 32 to which a target 31 for discharging a coating material is attached, a shield 38 disposed so as to surround the side and upper side of the cathode unit 32, and an upper portion covering the upper side of the shield 38. A convex cap portion 40 (upward). The cap portion 40 has a roof shape and includes a ridge line 42 extending in the direction of the central axis 9 and surfaces 43 and 44 inclined downward on both sides of the ridge line 42. The tip portions 45 and 46 of the inclined surfaces 43 and 44 are bent in the vertical direction and fixed to the side surface of the shield 38. Even if the powder 3 diffuses above the sputtering unit 30, the inclined surfaces 43 and 44 can suppress the powder 3 from being deposited on the shield 38.

  The cathode unit 32 serving as the center of the sputtering unit 30 is fixed to the arm 70 via a shield 38 and an insulator (not shown), and is independent of the drum 10 on the substantially center of the drum 10, that is, on the central axis 9. Then, it is supported from the vacuum vessel 5 (in a suspended manner). Further, the sputtering unit 30 can be pulled out from the drum 10 by being relatively separated from the end plate 7 a and the end plate 7 b while sliding along the central axis 9.

  The cathode unit 32 includes a housing 33, a magnet 34 housed in the housing 33, a return yoke 35 that allows the magnetic flux of the magnet 34 to pass through, a backing plate 36 that fixes the magnet 34, and a target attached to the backing plate 36. 31. As the magnet 34, a non-equilibrium magnetron is employed, and the plasma region can be expanded closer to the powder 3 that is a coating object by non-equilibrium magnetic field sputtering (unbalanced magnetron sputtering, UBMS). The magnet 34 may not be non-equilibrium, and a method more suitable for the coating material (coating composition) such as a dual magnetron can be adopted.

  The shield 38 is disposed so as to cover the cathode unit 32 except for the surface 31 a of the target 31, and is grounded via the arm 70. For this reason, only the surface 31a of the target 31 is prevented from being sputtered.

  The power supply unit 50 is electrically connected to the cathode unit 32 by a wiring 59 that passes through the arm 70. The power supply unit 50 includes an RF power supply 51, a matching box (MB) 52 connected in series on the output side of the RF power supply 51, and a low-pass filter (LPF) circuit 54 for the output (first RF output) of MB52. And a DC power source 53 connected so as to be turned on and off by a switch 55. The DC power source 53 is wired so that a negative voltage is output with respect to the RF output. The power supply unit 50 turns on and off the switch 55 to thereby generate a first AC power (first RF power, RF output) output from the RF power supply 51 and a DC component (DC power) in the first RF power. Can be switched and supplied with the second AC power (second RF power, RF output) superimposed. For this reason, the coating apparatus 1 can coat the powder 3 using not only the conductive target 31 but also a non-conductive target 31 such as an oxide.

  In the coating apparatus 1, by superimposing the DC power on the first RF power, the sheath electric field of the plasma formed by the first RF power can be made larger than the case of the RF power alone, and the plasma It can be stabilized and the sputtering efficiency can be increased.

(Example)
As an example, the surface of fine particles (micron particles) 2 of SiO ₂ was coated with chromium (Cr) using the coating apparatus 1.

First, the end plate 7 a and / or 7 b of the vacuum vessel 5 was opened, and the powder 3 was introduced into the drum 10. In this example, 100 g of the powder 3 composed of SiO ₂ fine particles 2 having an average particle diameter of 4 to 5 μm was measured and placed in the drum 10.

  Next, a target 31 to be coated on the powder 3 was attached to the cathode unit 32. In this example, a Cr target 31 having a purity of 99.9% as a coating material was attached to the cathode unit 32. Thereafter, the end plates 7 a and 7 b were closed, and the vacuum vessel 5 was evacuated by the vacuum generator 81.

  After evacuation, the heating mechanism 83 is turned on to heat the inside of the drum 10 to 120 ° C., and the drum 10 and the stirring bar 20 are asynchronously oscillated at a symmetric angle of 15 degrees about the lower part of the drum 10. I let you. Thereby, the powder 3 was dispersed and heated before sputtering, and the powder 3 was dehydrated and degassed to make it difficult to aggregate.

  When the pretreatment is completed, the Ar partial pressure in the vacuum vessel 5 is set to 1 Pa, and 400 W of RF power (first RF power) is first supplied from the power supply unit 50 to the cathode unit 32 to generate plasma 39, Next, the second RF power obtained by superimposing the DC component of (−) 240 V on the first RF power was supplied to the cathode unit 32 to maintain the plasma 39. In that state, sputtering was performed for 1 hour.

  During sputtering, the drive units 60 and 65 were controlled by the control unit 69, and the drum 10 and the stirring bar 20 were asynchronously swung at a symmetrical angle of 15 degrees about the lower part of the drum 10.

After the sputtering, the SiO ₂ powder 3 coated with Cr was taken out and the particle size distribution was measured. The average value of the particle size distribution was 6.0 μm.

FIG. 3A shows the result of the structural analysis. As shown in FIG. 3A, the SiO ₂ fine particles 2 were almost uniformly covered with the Cr coating material 4. Therefore, it was found that the powder 3 containing micron-sized fine particles 2 and the surface of each fine particle 2 coated almost uniformly can be produced by the coating apparatus 1.

  FIG. 3B shows another example of the fine particles 2 that can be produced by the coating apparatus 1. In this example, the coating material 4 is formed intermittently in the shape of islands or grains on the surface of the fine particles 2 serving as the core. In order to form the coating material 4 on the surface of the fine particles 2 in the form of islands or grains, it can be formed by sputtering, for example, by sputtering under a high Ar partial pressure or by lowering the RF power. .

  Further, the coating apparatus 1 coats the fine particles 2 (powder 3) by discharging the coating composition into the drum 10 by RF sputtering (RF sputtering) using RF power. Therefore, the coating composition is not limited to metal and may be an oxide. Further, since the sputtering unit 30 is disposed along the central axis 9 at the center of the drum 10, the sputtering unit 30 can be brought close to the powder 3 that coats the target 31. For this reason, sputtering efficiency can be raised.

  It can be said that the coating apparatus 1 is a sputtering apparatus in which the cylindrical drum 10 (body portion 11) is anodized and the cathode unit 32 is arranged along the center. This configuration can also be regarded as a hollow anode configuration in which the anode side is a cylinder, and can be said to be a form in which plasma is easily confined. On the other hand, a flat cathode is arranged in a cylindrical anode, and the distance between the cathode and anode is likely to change, and the potential difference at the end with respect to the center of the cylinder tends to be different. Depending on the case, it may be difficult to generate stable plasma over the entire region inside the cylindrical body 11. On the other hand, the power supply unit 50 of this example can supply the second RF power obtained by superimposing the DC power on the RF power, and the cathode can be connected even under conditions or places where the plasma is difficult to stabilize by self-bias. Stable plasma can be generated and maintained by pulling the potential to the negative side beyond the self-bias.

  Further, in this coating apparatus 1, the sputtering unit is supported by the drive gear 64 or the like so that the center of the cylindrical body 11 of the drum 10 coincides with the central axis 9, and passes through the opening 13 inside the body 11 of the drum 10. 30 is inserted. Since the sputtering unit 30 is disposed so as to be located substantially at the center of the body portion 11, the drum 10 and the stirring bar 20 can be rotated or swung without interfering with the sputtering unit 30. Further, the powder 3 may be swollen not only in the radial direction inside the body 11, that is, in the direction along the inner surface 19, and the powder 3 that coats the target 31 of the sputtering unit 30 may be used. To be close to. For this reason, sputtering efficiency can further be improved.

  At the time of coating, the powder 3 can be stirred only by rotating or swinging the drum 10. However, when the fine particles 2 constituting the powder 3 are submicron-sized or nano-sized, for example, about several μm or less, they tend to aggregate due to the influence of the quantum effect, and the drum 10 is simply rotated. Then, it is difficult to disperse the aggregated fine particles 2.

  The coating apparatus 1 breaks the powder 3 agglomerated between the inner surface 19 and the stirring bar 20 that moves differently from the inner surface 19 by rotating or swinging the stirring bar 20 by an independent drive unit 65 to form fine particles. 2, the powder 3 is scraped up with the stirring bar 20 to be decomposed into fine particles 2, and further, the powder 24 is moved over the slope 24 or 25 of the stirring bar 20 to be decomposed into fine particles 2. be able to. By combining these series of processes, movements, and effects, the agglomerated powder 3 can be mechanically and thermally dispersed in the individual fine particles 2.

  The drum 10 and the stirring bar 20 may be driven asynchronously or may be driven synchronously. Moreover, the drum 10 and the stirring bar 20 may be moved regularly, or may be moved irregularly using an appropriate random number. The amplitude and the period for swinging the drum 10 and the stirring bar 20 can be appropriately adjusted by the control unit 69 depending on the amount, material, particle size, degree of aggregation, etc. of the powder 3.

  Further, the drum 10 and the stirring bar 20 move with respect to the vacuum vessel 5, whereas the sputtering unit 30 is fixed to the vacuum vessel 5. Accordingly, the fine particles 2 stirred and dispersed by the drum 10 and the stirring bar 20 move relatively violently with respect to the sputtering unit 30 and move around in the plasma formed by the sputtering unit 30. Therefore, even if the coating conditions realized by the sputtering unit 30 are different inside the drum 10, since the fine particles 2 move to various places, the coating conditions are easily averaged. Therefore, it is possible to produce and provide a powder 3 composed of fine particles 2 that are uniformly coated.

  FIG. 4 shows a different example of the coating apparatus 1. In the coating apparatus 1, the drum 10 does not include the tapered portions 16 a and 16 b, and the inner surface 19 is formed only by the body portion 11. The inside of the drum 10 has a cylindrical shape, not a barrel shape. For this reason, the swing part 21 of the stirring bar 20 is linear so as to follow the cylindrical inner surface 19 of the drum 10. When the internal volume of the drum 10 is small, the plasma displacement in the central axis direction is not so large. Therefore, the powder 3 does not have to be actively concentrated on the central portion of the drum 10, and conversely, the coating time can be shortened by dispersing (distributing) the powder 3 so as to spread at both ends of the drum 10. .

  FIG. 5 is a cross-sectional view showing an example of a stirring member that moves in conjunction with the stirring bar 20. This stirring member is a chain 26 that is longer than the metal stirring bar 20, and several places, in FIG. 5, three places 26a, 26b, and 26c are fixedly connected to the stirring bar 20 so as to have a slack. Yes. Therefore, when the stirring bar 20 is swung, the operating portions 26d and 26e of the chain 26 move in a complicated manner along the inner surface 19 of the drum 10 in conjunction with the movement of the stirring bar 20, and a part of the chain 26 is It moves while contacting the inner surface 19.

  When the stirring bar 20 is driven asynchronously with the drum 10, it is necessary to ensure a clearance even if it is very small between the stirring bar 20 and the drum 10. When the diameter of the fine particles 2 is reduced, the stirring efficiency is further improved by stirring the powder 3 while contacting the inner surface 19 of the drum 10. Therefore, it is effective to provide a stirring member that is directly or indirectly driven by the stirring bar 20 and at least a part of which is in contact with the inner surface 19 of the drum 10. The stirring member may be a wire, a brush, or the like, but is preferably a member having a sufficiently large diameter (effective size) with respect to the fine particles 2 included in the powder 3. For example, the chain 26 connected to the stirring bar may be used, or a ball moved by the stirring bar may be used. For example, by introducing a plurality of metal balls having a diameter of, for example, about 5 mm into the drum 10 together with the powder 3, the metal balls randomly move along the inner surface 19 of the drum 10 in conjunction with the movement of the stirring bar 20. Make a move. The powder 3 colliding with the metal sphere is dispersed and stirred by the impact of the collision. These stirring members are not limited to one type, and a plurality of types may be used simultaneously.

  In the present embodiment, the body portion 11 of the drum 10 has a cylindrical shape. However, if the drum 10 is only rotated without being rotated, the upper portion of the drum 10 is open, for example, a half pipe shape or the like. It may be. Sputtering is the most preferable example of the dry process, but a unit (dry process unit) having a function of coating in the gas phase by a different method such as arc vapor deposition is installed instead of or together with the sputtering unit. May be.

DESCRIPTION OF SYMBOLS 1 Coating apparatus 5 Vacuum container 10 Drum 20 Stirring bar 30 Sputtering unit

Claims (9)

A vacuum vessel;
A cylindrical container that rotates or swings with respect to the vacuum container around a central axis extending in a horizontal axis direction in the vacuum container;
A stirring bar extending in the direction of the central axis along the inner surface of the cylindrical container, wherein the stirring bar rotates or swings around the central axis with respect to the vacuum container independently of the cylindrical container. A stirring bar for stirring the powder in the container,
A coating apparatus having a dry process unit installed in the cylindrical container and discharging a coating material.   2. The plurality of drive shafts for supporting the lower half of the cylindrical container inside the vacuum container according to claim 1, wherein the drive shaft extends along the outside of the cylindrical container and is perpendicular to the central axis. A coating apparatus having a plurality of drive shafts spaced apart from each other. In Claim 1 or 2, the dry process unit includes a sputtering unit,
The coating apparatus further includes a power supply unit that switches and supplies the first AC power and the second AC power in which a DC component is superimposed on the first AC power to the sputtering unit.   4. The coating apparatus according to claim 3, wherein the sputtering unit is a non-equilibrium magnetic field sputtering unit. 5. The method according to claim 1, wherein at least one end of the cylindrical container is an opening,
The coating apparatus which has a supporting member which supports the said dry process unit independently with respect to the said cylindrical container within the said vacuum container.   6. The coating apparatus according to claim 1, further comprising an upwardly protruding cap portion that covers an upper portion of the dry process unit.   The coating apparatus according to claim 1, wherein the cylindrical container includes a portion whose inner diameter is smaller than a diameter on a central side.   8. The stirring member according to claim 1, wherein the stirring bar is non-contact with the inner surface of the cylindrical container, and is further a stirring member driven directly or indirectly by the stirring bar. The coating apparatus which has a stirring member in which a part contacts the inner surface of the said cylindrical container. A method for producing a powder containing fine particles coated on a surface by a coating apparatus,
The coating apparatus includes a vacuum vessel,
A cylindrical container rotatably supported around a central axis extending in the horizontal axis direction in the vacuum container;
A stirring bar extending in the direction of the central axis along the inner surface of the cylindrical container;
A dry process unit installed in the cylindrical container and releasing a coating material;
The method is
The powder is put into the cylindrical container, the cylindrical container is rotated or swinged with respect to the vacuum container around the central axis, and the stirring bar is independent of the operation of the cylindrical container. Rotating or peristating with respect to the vacuum vessel about the central axis;
Releasing the coating material from the dry process unit in parallel with the rotating or peristating.

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