JP2006213944A - Apparatus for coating powder and method for producing coated powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To deposit a film of high quality on the surface of base material powder in such a manner that variation between lots is minimized. <P>SOLUTION: The apparatus for coating powder is provided with: a body part 11 whose inside is packed with target powder and base material powder; heating means 12 for heating the inside of the body part 11; a stirring means 13a for stirring the target powder and the base material powder inside the body part 11; and an exhausting means 15 for exhausting the inside of the body part 11 and making the same into a vacuum state, and the target powder and the base material powder are heated in a state where they are stirred inside the body part 11 while the inside of the body part 11 is exhausted by the exhausting means 15, thus the surface of the base material powder is coated with a film containing at least one compositional component composing the target powder. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a powder coating apparatus and a method for producing a coated powder.

  In general, soft magnetic materials used in various electromagnetic circuit components such as magnetic cores, motor cores, solenoid coils, ignition coils, reactors, choke coils, or sensors are required to have low iron loss. Increasing the eddy current loss reduces the coercive force to reduce the hysteresis loss. In recent years, there is a high demand for miniaturization and high responsiveness of electromagnetic circuits, and accordingly, it is required to further increase the electrical resistance of soft magnetic materials.

As a method for producing such a soft magnetic material, for example, as shown in the following Patent Document 1, a colloid containing an insulating material is infiltrated into a base powder (for example, Fe powder), and the surface of the base powder There is known a method in which a coating powder in which a colloidal layer containing an insulating material is formed is formed, and then the coating powder is compressed to form a green compact and then fired (hereinafter referred to as “Prior Art 1”). ").
There is also known a method in which an insulating substance powder is mixed with the base material powder, and the mixed powder is compressed to form a green compact, which is then fired (hereinafter referred to as “Prior Art 2”). .
Further, as shown in Patent Documents 2 and 3 below, a coating powder in which an insulating film such as ferrite or a glassy insulating layer is formed on the surface of the base powder by a wet method such as chemical plating or coating is formed. There is also known a method in which a green compact is formed by compressing and then fired (hereinafter referred to as “Prior Art 3”).

  In addition, the soft magnetic material obtained by the above-described conventional methods 1 to 3 has a high coercive force due to the strain generated when being compressed and formed into a green compact, and the hysteresis loss of iron loss is reduced. Therefore, by performing annealing, the coercive force is reduced and the hysteresis loss is reduced.

However, the prior arts 1 to 3 have a problem that it is difficult to manufacture a high-resistance soft magnetic material with an increased electrical resistance.
That is, in the soft magnetic material obtained by the prior art 1, since the strength of the colloid layer is weak, the colloid layer is torn during compression and the surface of the base powder is exposed, so that these base materials are exposed. There was a problem in that it was difficult for the soft magnetic material obtained by firing the powders to come into contact with each other and having high resistance.
Moreover, in the soft magnetic material obtained by the prior art 2, it is virtually impossible to completely cover the surface of the base material powder with the insulating substance powder, and the base material powders are also in contact with each other. As a result, there is a problem that it is difficult to provide the soft magnetic material with high resistance.
Furthermore, in the soft magnetic material obtained by the prior art 3, the insulating coating reacts with the base powder to reduce the insulating properties of the insulating coating, and during the compression, the insulating coating is broken, etc. When the base powder is exposed, the base powders are brought into contact with each other, and it is difficult to provide the soft magnetic material with high resistance.

  That is, as described above, there is a problem that it is difficult to form the coating powder without exposing the surface of the base powder.

As a means for solving such a problem, for example, as shown in Patent Document 4 below, after filling the inside of the container with the base material powder and the insulating substance powder, the inside is filled with 1 × 10 ⁻² Torr. The method and apparatus for forming the coating powder is applied by evacuating to a degree and then sealing the container to form a sealed container, and then heating the sealed container while rotating around its axis. It is possible to do. That is, in this case, by rotating and heating the sealed container, the insulating substance powder is vaporized in the form of atoms or clusters, and the vaporized component is reacted with the surface of the substrate powder, whereby the substrate powder It becomes possible to form a coating powder by forming an insulating coating on the surface side of the substrate.
JP-A-5-258934 Japanese Patent Laid-Open No. 11-1702 JP-A-8-250317 JP 2001-254168 A

  However, in the prior art, since the inside of the sealed container is maintained in a vacuum state by evacuating the container and then sealing the container, it is difficult to achieve a high vacuum without variation among the sealed containers. was there. Therefore, depending on the sealed container, oxygen, nitrogen, carbon dioxide, etc. (hereinafter referred to as “oxygen”, etc.) may remain in the inside. In this case, before the vaporized component reacts with the surface of the base powder. In addition, there is a problem that the reaction affinity between the vaporized component and the surface of the base material powder is impaired, and it becomes difficult to form the insulating coating with high quality. .

  The present invention has been made in view of such circumstances, and a powder coating apparatus and a coating powder capable of forming a high-quality coating on the surface of a base powder with minimal variation between lots. It aims at providing the manufacturing method of.

  In order to solve the above problems and achieve the above object, the powder coating apparatus of the present invention includes a main body portion filled with a target powder and a base material powder, and heating for heating the inside of the main body portion. Means, stirring means for stirring the target powder and the base material powder inside the main body, and exhaust means for evacuating the inside of the main body to bring it into a vacuum state. While evacuating the inside of the part, the surface of the base powder is heated with the target powder and the base material powder being stirred inside the main body part. It is configured to be coated with a film containing at least one.

  According to this invention, the target powder and the base material powder are heated while being stirred inside the main body while exhausting the inside of the main body by the exhaust means. Even when oxygen or the like remains, the stirring and heating can be performed while discharging the oxygen or the like from the inside of the main body. Therefore, when the target powder is vaporized in the form of atoms or clusters by heating the inside of the main body or the like, the vaporized component reacts with the oxygen or the like before reacting with the surface of the substrate powder. This can be suppressed. Thereby, it becomes possible to avoid that the reaction affinity of the said vaporization component and the surface of a base material powder is impaired, and a film can be formed in high quality.

Furthermore, since the inside of the main body is heated while the inside of the main body is evacuated by the exhaust means, the variation between lots in the amount of the oxygen or the like remaining inside the main body at the time of heating Therefore, it is possible to form a high-quality coating film with minimal variation between lots.
Furthermore, since the target powder and the base material powder are directly filled into the main body, the apparatus can be provided with good handleability.

Here, the stirring means includes a drive unit that supports the main body portion so as to be rotatable about its axis, and the exhaust means is directly connected to the main body portion from the outside, and the main body portion is arranged around the axis line. It is desirable to have a structure that rotates together with the main body when rotating.
In this case, since the exhaust means is directly connected to the main body portion from the outside and is configured to rotate together with the main body portion, the connecting portion between the exhaust means and the main body portion when the main body portion rotates. Does not slide. Thereby, it becomes possible to make the inside into a high vacuum degree, rotating a main-body part.

The exhaust means is preferably arranged coaxially with the axis of the main body.
In this case, the rotation of the main body can minimize the centrifugal force acting on the exhaust means, and can reliably achieve a high degree of vacuum inside the main body. It is possible to maintain the degree over a long period.

Furthermore, it is desirable that the agitation means includes a fin-attached plate in which a plurality of fins extending in the radial direction from the radial center portion are provided on the surface of the disc.
In this case, it is possible to easily and surely agitate the target powder and the base powder so as not to contact each other.

The target powder is preferably Mg powder or Mg-based alloy powder, and the base material powder is preferably Fe powder or Fe-based alloy powder having an oxide film formed on the surface thereof.
In this case, it can be formed by firmly bonding the coating on the surface side of the base powder. That is, since Mg powder or the like has the property of being easily oxidized, it is possible to achieve good reaction affinity between the vaporized component such as Mg powder and the surface side (oxide film) of the base powder. This makes it possible to suppress the vaporization component from reacting with the oxygen or the like remaining inside the main body before reacting with the surface of the base powder, It is possible to reliably realize the formation of the coating film with high quality.

  Moreover, the manufacturing method of the coating powder of this invention uses the powder coating apparatus in any one of Claim 1 to 5, and coat | covers the surface of the said base material powder with the said film, and forms coating powder. Features.

  According to the present invention, it is possible to form a high-quality film on the surface of the base powder with minimal variation between lots.

FIG. 1 shows a first embodiment of the present invention. The powder coating apparatus 10 of this embodiment includes a main body 11 filled with a target powder and a soft magnetic base powder having an oxide film formed on the surface, and heating for heating the inside of the main body 11. Means 12, stirring means 13 for stirring the target powder and the base material powder inside the main body 11, and exhaust means 15 for exhausting the inside of the main body 11 to make a vacuum state. While exhausting the inside of the main body 11 by the above, the target powder and the base material powder inside the main body 11 in an inert gas atmosphere or vacuum atmosphere of 1 × 10 ⁻¹² to 1 × 10 ⁻¹ MPa. By heating in a stirred state, a ternary complex oxide film composed of the metal material of the target powder, the soft magnetic material of the substrate powder, and oxygen is formed on the surface of the substrate powder. There is a.

  The main body 11 is formed into a bottomed cylindrical shape from stainless steel or a heat-resistant alloy such as molybdenum, tantalum, or tungsten, or a molybdenum alloy containing titanium and zirconium, and its axis O is parallel to the vertical direction. The vertical structure is arranged vertically. The main body 11 has a large-diameter portion 11f, a small-diameter portion 11b having a smaller diameter than the large-diameter portion 11f, and a large-diameter portion 11b that extends continuously upward from the upper end of the large-diameter portion 11f in the axis O direction It is made into the schematic structure provided with the diameter reducing part 11a continuously provided in the axis line O direction of the diameter part 11f, and being gradually diameter-reduced as it goes below. An opening communicating with the inside of the main body 11 is formed on the upper end surface of the small diameter portion 11b.

  On the small diameter portion 11 b side of the large diameter portion 11 f, that is, on the upper end portion, a charging port 11 c through which the target powder and the base material powder are charged into the main body portion 11 is provided. Furthermore, the coating powder in which the ternary complex oxide film is formed on the surface of the base powder is taken out from the inside of the main body 11 to the outside at the lower end of the main body 11, that is, the reduced diameter portion 11 a. A take-out port (not shown) is provided.

  Then, both ends of the main body 11 in the direction of the axis O, that is, the reduced diameter portion 11a and the small diameter portion 11b are respectively coaxially with the main body 11 so as to extend outward in the direction of the axis O. Second shafts 11d and 11e are provided. The first shaft 11d provided in the reduced diameter portion 11a is connected to a first motor (drive portion) (not shown), and the second shaft 11e provided in the small diameter portion 11b is supported by a bearing (not shown). As described above, when the rotational driving force of the first motor is transmitted to the first shaft 11d, the main body 11 and the second shaft 11e are also rotated around the axis O.

  The heating means 12 is a cylindrical body and is disposed coaxially with the main body 11 so as to surround the outer peripheral surface of the main body 11. The heating means 12 causes the target powder and the base powder filled in the main body 11 to be at a temperature higher than the vaporization temperature of at least the metal substance constituting the target powder and lower than the melting temperature of the base powder. The main body 11 is heated from the outside. Note that the insertion port 11 c of the main body 11 is provided in the main body 11 so that the opening is located outside the heating means 12.

The small diameter portion 11b is provided with the water cooling jacket 14 and the exhaust means 15 coaxially with the axis O in this order in the direction away from the large diameter portion 11f.
The water-cooling jacket 14 has a donut shape, and is disposed in the main body 11 with the small-diameter portion 11b inserted therein, so that the refrigerant circulates on the outer peripheral surface side of the small-diameter portion 11b.

  The exhaust means 15 is directly connected to the main body portion 11 coaxially with the main body portion 11 from the outside so as to close the opening of the small diameter portion 11b, and when the main body portion 11 rotates around the axis O. The main body 11 is configured to rotate together. The exhaust means 15 is connected to a vacuum pipe 15a communicated with a vacuum pump (not shown) so that the inside of the main body 11 can be exhausted. Examples of the exhaust means 15 include a rotary pump and a mechanical pump. Further, a filter or the like (not shown) is disposed at a connection portion between the inside of the exhaust means 15 and the inside of the small diameter portion 11b, and when the inside of the main body portion 11 is exhausted by the exhaust means 15, The internal target powder and substrate powder are not discharged.

  With the above configuration, when the gas inside the main body 11 is exhausted from the exhaust means 15 via the vacuum pipe 15a by the vacuum pump, the gas heated by the heating means 12 is once cooled by the water cooling jacket 14. After that, the exhaust means 15 and the vacuum pipe 15a are sequentially passed.

  In this embodiment, the stirring means 13 is constituted by a finned plate 13a disposed coaxially with the axis O of the main body portion 11 inside the lower end portion of the large diameter portion 11f, and the first motor. ing. The finned plate 13a is rotatably supported around the axis O by a second motor (not shown) installed inside the small diameter portion 11b, and faces one surface of the disk, that is, the small diameter portion 11b of the main body portion 11. As shown in FIG. 1 (b), a plurality of fins 13b extending in a state of being curved radially outward from the radial center are provided on the surface. The finned plate 13a is formed of stainless steel or the heat resistant alloy, and a hole 13c in which a shaft (not shown) connected to the second motor is disposed is formed in a central portion in the radial direction.

  With the above configuration, the rotation of the main body 11 around the axis O by the first motor causes a centrifugal force to act on the target powder and the base powder filled in the main body 11, and the finned plate 13a. Is rotated around the axis O by the second motor so that a lift force directed upward in the direction of the axis O can be mainly applied to each powder. Here, the finned plate 13a is supported by the second motor so as to be capable of rotating in the forward and reverse directions around the axis O, thereby changing the direction of the centrifugal force acting on each powder by the finned plate 13a. Be able to. As described above, the target powder and the base material powder filled in the main body 11 are stirred to such an extent that these powders do not contact each other. That is, stirring is performed so that the surface of each individual powder is exposed. That is, the mean free path of each powder can be secured.

  Here, examples of the target powder include Mg powder, Mg—Al based alloy powder, Mg—Si based alloy powder, Mg—Si—Al based alloy powder, and the like. Examples of the base powder include Fe powder, Fe-Al alloy powder, Fe-Ni alloy powder, Fe-Cr alloy powder, Fe-Si alloy powder, Fe-Si-Al alloy powder, Examples thereof include Fe—Co alloy powder, Fe—Co—V alloy powder, and Fe—P alloy powder.

  Next, a method for producing coated powder by the powder coating apparatus 10 configured as described above will be described. In the present embodiment, Mg powder having an average particle diameter of 50 μm is employed as the target powder, and Fe powder having an average particle diameter of 70 μm is employed as the base powder.

  First, when the Fe powder and Mg powder are put into the main body 11, the Fe powder is preliminarily placed in an oxidizing atmosphere of about 50 ° C. to 500 ° C. for several minutes to several tens of hours to perform an oxidation treatment. An oxide film is formed. Next, after mixing the Fe powder and Mg powder on which this oxide film is formed, the mixed powder is introduced into the main body 11 from the inlet 11c, and then the opening of the inlet 11c is closed.

Then, the heating means 12 causes the inside of the main body 11 to reach a temperature higher than the vaporization temperature of the metal substance (Mg) constituting the target powder (Mg powder) and lower than the melting temperature of the base powder (Fe powder) (about In the state heated to 150 ° C. to 1100 ° C., the inside of the main body portion 11 in an inert gas atmosphere is exhausted by the vacuum pump through the vacuum pipe 15a and the exhaust means 15, and the internal pressure is reduced to about 1 × 10 ⁻¹² MPa to ¹ × 10 ⁻¹ MPa. At this time, the gas inside the main body 11 passes through the small-diameter portion 11b in which the water cooling jacket 14 is disposed. Therefore, after the gas heated to high temperature by the heating means 12 is cooled by the water cooling jacket 14, the exhaust means 15 is passed through. pass. Thereby, the inside of the main body 11 is made an inert gas atmosphere and a vacuum atmosphere.

  Then, the main body portion 11 is rotated around the axis O by the first motor, whereby centrifugal force is applied to the Fe powder and Mg powder filled in the main body portion 11. Further, by rotating the finned plate 13a around the axis O by the second motor, a lift force directed upward in the direction of the axis O is mainly applied to the Fe powder and the Mg powder. Here, by changing the forward / reverse rotation of the finned plate 13a at a predetermined timing, the direction of centrifugal force by the finned plate 13a acting on each powder is changed.

The outer diameter of the large-diameter portion 11f of the main body 11 is about 600 mm and the size in the direction of the axis O is about 2500 mm. The main body 11 has 99.8 kg of Fe powder and 0. When 2 kg is filled, the main body 11 is rotated at about 0.2 rpm to 3 rpm, and the finned plate 13 a is rotated at about 0.2 rpm to 120 rpm.
As described above, the individual Fe powder and Mg powder are stirred to the extent that they do not contact each other as described above.

In this state and while evacuating the inside of the main body 11 by the exhaust means 15, holding for several minutes to several tens of hours allows the Fe powder (base powder) to become the Mg component (metal) of the Mg powder (target powder). (Material) is exposed to gas vaporized in an atomic or cluster form, and from the surface of Fe powder, Mg (target powder metal material), Fe (base powder metal material), and oxygen O A ternary composite oxide film is formed having a concentration gradient in which Mg and O decrease from the surface of the oxide film toward the inside thereof, while Fe increases toward the inside thereof, and the coating powder Form.
Thereafter, a take-out port (not shown) is opened to take out the composite powder, and then the composite powder is placed in an oxidizing atmosphere at about 50 ° C. to 500 ° C. for several hours for post-oxidation treatment. And after compressing this composite powder and shape | molding a green compact, the soft-magnetic material was formed by baking at about 400 to 1300 degreeC.

  As described above, according to the powder coating apparatus 10 and the coating powder manufacturing method according to the present embodiment, the target powder and the base powder are removed from the main body 11 while the inside of the main body 11 is exhausted by the exhaust means 15. In the case where the gas vaporized in the form of atoms or clusters that reacts with oxygen or the like remains in the main body portion 11, the reacted gas is heated in the main body portion 11. It becomes possible to stir and heat while discharging from the inside of 11. Therefore, when the target powder is vaporized in the form of atoms or clusters by heating the inside of the main body 11 or the like, the vaporized component reacts with the oxygen or the like before reacting with the surface of the substrate powder. It becomes possible to suppress doing. Thereby, it becomes possible to avoid that the reaction affinity of the said vaporization component and the surface of a base material powder is impaired, and a film can be formed in high quality.

Further, similarly, since the inside of the main body portion 11 is heated while the inside of the main body portion 11 is exhausted by the exhaust means 15, the amount of the oxygen or the like remaining inside the main body portion 11 during this heating. As a result, it is possible to minimize the variation between lots, and it is possible to form a high quality coating film with a minimum variation between lots.
Furthermore, since the target powder and the base powder are directly filled into the main body 11, the apparatus 10 can be provided with good handling properties.

  Further, since the exhaust means 15 is directly connected to the main body portion 11 from the outside and rotates together with the main body portion 11, the exhaust means 15 and the main body portion 11 are connected when the main body portion 11 rotates. The part does not slide. This makes it possible to keep the inside of the main body 11 at a high degree of vacuum while rotating.

  Further, since the exhaust means 15 is disposed coaxially with the axis O of the main body 11, the centrifugal force acting on the exhaust means 15 is minimized by the rotation of the main body 11, and the main body It is possible to reliably realize a high degree of vacuum in the interior of the head 11, and it is possible to maintain such a degree of vacuum over a long period of time.

  Furthermore, since the stirring means 13 includes a fin-attached plate 13a in which a plurality of fins 13b extending in the radial direction from the radial center portion are provided on the surface of the disk, the target powder and the base material are provided. It is possible to easily and surely agitate the powders so that they do not contact each other.

  Furthermore, the target powder is Mg powder or Mg-based alloy powder, and the base material powder is Fe powder or Fe-based alloy powder having an oxide film formed on the surface thereof. It can be formed by firmly bonding the coating to the surface side of the material powder. That is, since Mg powder or the like has the property of being easily oxidized, it is possible to achieve good reaction affinity between the vaporized component such as Mg powder and the surface side (oxide film) of the base powder. This makes it possible to suppress the vaporization component from reacting with the oxygen or the like remaining in the main body 11 before reacting with the surface of the base powder, It is possible to reliably realize the formation of the coating film with high quality.

  Furthermore, when manufacturing the said coating powder, the inside of the main-body part 11 is higher than the vaporization temperature of the metal substance (Mg) which comprises target powder (Mg powder) by the heating means 12, and is base material powder (Fe powder) Therefore, it is possible to vaporize the Mg component of the Mg powder without melting the Fe powder, and the Fe powder is contained in the gas containing the vaporized Mg component. Can be exposed to. Therefore, it is possible to form a uniform coating on the surface of the Fe powder by firmly bonding it without exposing the surface.

Further, after forming an oxide film on the surface of the Fe powder, the Fe powder and the Mg powder are put into the main body 11, and then the inside of the main body 11 is 1 × 10 ⁻¹² to 1 × 10 6. ^{Since the} coating powder is formed in an inert gas atmosphere or a vacuum atmosphere of ^-1 MPa, the surface of the Fe powder is homogeneously composed of the Fe component of the Fe powder, the Mg component of the Mg powder, and oxygen O. It is possible to form the ternary complex oxide film by strongly bonding it.

  In particular, in this embodiment, the coating formed on the surface of the Fe powder has a concentration gradient in which Mg and O decrease from the surface of the coating toward the inside thereof, while Fe increases toward the inside. Since it was formed as a ternary complex oxide film, the obtained individual coating powder can be provided with high insulation. Therefore, combined with the fact that it is possible to prevent the tearing of the coating as described above, it is possible to more reliably form a high-resistance soft magnetic material.

  Hereinafter, the Example which forms the said coating powder with the powder coating apparatus 10 and the manufacturing method of coating powder mentioned above is described. Here, since the manufacturing conditions for forming the oxide film on the surface of the Fe powder are the same in each example and the comparative example described later, first, the manufacturing conditions for this oxide film will be described. That is, the Fe powder was placed in the atmosphere at a temperature of 220 ° C. and held for 2 hours, and an oxidation treatment was performed to form an oxide film on the surface.

In Example 1, after mixing the Fe powder with the oxide film formed thereon and the Mg powder, the mixed powder was adjusted to an internal temperature of 650 ° C. and an internal pressure of 1.33 × 10 ⁻⁸ kPa ( A vacuum atmosphere) and an inert gas atmosphere are introduced into the main body 11 from the inlet 11c. The body powder 11 was rotated around the axis O at 3 rpm, and the finned plate 13a was held around the axis O at 10 rpm for 1 hour to form the coating powder. Next, when the concentration distribution of Mg, Fe and O in the ternary composite oxide film of the coating powder in the thickness direction was measured using an Auger electron spectrometer, Mg and O While decreasing from the surface toward the inside, it was confirmed that Fe increased toward the inside.

  In Example 2, the coating powder obtained in Example 1 was placed in the atmosphere at a temperature of 220 ° C. and held for 2 hours for oxidation treatment. Then, when the concentration distribution of Mg, Fe and O in the ternary composite oxide film of the coating powder in the thickness direction was measured using an Auger electron spectrometer, Mg and O were observed on the surface of the oxide film. From this, it was confirmed that Fe decreased toward the inside while Fe increased toward the inside. Furthermore, it was confirmed that no Fe was present on the surface of the ternary composite oxide film.

  Next, the coated powders of Examples 1 and 2 were compressed to form a plate-like green compact having a rectangular shape in plan view of 55 mm length × 10 mm width × 5 mm thickness, and an outer diameter of 35 mm. A ring-shaped green compact having a ring shape with an inner diameter of 25 mm and a thickness of 5 mm was molded. These green compacts are placed in a nitrogen atmosphere at a temperature of 600 ° C. and held for 30 minutes and fired to form a plate-like soft magnetic material and a ring-like soft magnetic material. While measuring the relative density, specific resistance, and bending strength of the material, the ring-shaped soft magnetic material was wound, and the magnetic flux density was measured with a BH tracer. These results are shown in FIG.

  In the soft magnetic material of the comparative example shown in this figure, after mixing the Mg powder and the Fe powder with the oxide film formed in the air, immediately after forming the green compact as described above, It is obtained by firing a green compact. That is, the soft magnetic material of this comparative example is obtained by forming the green compact or the like using a mixed powder obtained by simply mixing in the air without being processed by the apparatus 10 shown in FIG. .

  From the results shown in FIG. 2, the soft magnetic material formed on the basis of the coating powder obtained in Examples 1 and 2 is superior in bending strength, magnetic flux density and specific resistance as compared with the comparative example. Was confirmed.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the said Example, although the said target powder and the said base material powder were heated inside the main-body part 11 made into 1 * 10 < ^-12 > ^-1 * 10 < ^-1 > MPa inert gas atmosphere, it replaced with this Alternatively, heating may be performed in a vacuum atmosphere. Further, the first and second motors are provided, and the main body 11 and the finned plate 13a are both rotated around the axis O. However, only one of the first and second motors is provided, and the main body is provided. 11 or only the finned plate 13a may be rotated. In this case, only the first motor is provided, and the finned plate 13a is disposed inside the lower end portion of the large diameter portion 11f in a fixed state coaxially with the axis O of the main body portion 11, and the main body by the first motor. Only the portion 11 may be rotated around its axis O.

Further, instead of stirring the target powder and the base powder by rotating, for example, at least one of the main body 11 and the finned plate 13a is vibrated in the direction of the axis O or the direction crossing the axis O, or You may make it stir by making it rock | fluctuate. Furthermore, instead of the finned plate 13a, a plurality of fin-like bodies may be arranged on the inner peripheral surface of the reduced diameter portion 11a with a predetermined interval in the circumferential direction.
Furthermore, in the said embodiment, although target powder was made into Mg powder and base material powder was made into Fe powder, it is not limited to this.

  Furthermore, as the base powder to be introduced into the main body 11, a structure in which an oxide film is formed on the surface of the metal powder or alloy powder is employed, but a base powder in which no oxide film is formed is employed. Also good. Moreover, although the method of forming the ternary composite oxide film on the surface of the base powder has been shown, the surface of the base powder is covered with a film containing at least one of the composition components constituting the target powder. In this case, the configuration of the coating is not limited to the ternary composite oxide film.

Moreover, in the said embodiment, although the said vertical structure was shown as the powder coating apparatus 10, it may replace with this and may employ | adopt the powder coating apparatus 20 of a horizontal structure as shown in FIG.
That is, the main body 21 has a bottomed cylindrical shape, and both end portions 21a and 21c are supported by the support portion 22 so that the axis O extends in the horizontal direction and is orthogonal to the vertical direction. It is arranged sideways in a state where it can be rotated by a motor. The water cooling jacket 14 and the exhaust means 15 are disposed at one end 21a in the axis O direction of the main body 21 and surrounds the outer peripheral surface of the central portion 21b of the main body 21 in the axis O direction. The heating means 12 is arranged so that both end portions 21a and 21c in the axis O direction protrude. Furthermore, the inlet 11c and the outlet 21d are disposed at each connecting portion between the both end portions 21a and 21c of the main body 21 and the central portion 21b so that the opening is located outward from the heating means 12. To do. Furthermore, elevating means (for example, a hydraulic cylinder) 23 that supports the end portions 21a and 21c so as to be elevable is disposed on the both end portions 21a and 21c, respectively. As a result, when the coating powder is formed and then taken out, the other end 21c provided with the takeout port 21c is moved downward, and the one end 21a is moved upward. Can be tilted with respect to the axis O. Note that a filter or the like (not shown) is disposed at a connecting portion between the inside of the one end 21 a of the main body 21 and the inside of the exhaust means 15, and the inside of the main body 21 is exhausted by the exhaust means 15. At this time, the target powder and base material powder inside the main body 21 are not discharged. Further, as shown in FIG. 3B, a plurality of fins 21e extending radially inward are provided on the inner peripheral surface of the central portion 21b with a predetermined interval in the circumferential direction. . The fins 21e may extend continuously in the direction of the axis O or may extend intermittently.
Even in such a configuration, substantially the same function and effect as the embodiment of FIG. 1 can be achieved.

  Here, in the powder coating apparatuses 10 and 20 shown in FIGS. 1 and 3, the exhaust means 15 is directly connected to the main body parts 11 and 21 from the outside, and the main body parts 11 and 21 rotate around the axis O. However, instead of this, instead of this, for example, a rotary joint is directly connected to the main body parts 11 and 21, and the inside of the main body parts 11 and 21 is connected via the rotary joint. And the exhaust means 15 may communicate with each other. That is, as long as the target powder and the base material powder can be heated while being stirred inside the main body parts 11 and 21, while the inside of the main body parts 11 and 21 is exhausted by the exhaust means 15, You may make it arrange | position the exhaust means 15 in the position independent of the main-body parts 11 and 21. FIG.

  Provided are a powder coating apparatus and a method for producing a coating powder, which can form a high-quality coating on the surface of a base powder with minimal variation between lots.

It is the schematic block diagram of (a) powder coating apparatus shown as 1st Embodiment which concerns on this invention, and (b) The top view of a board with a fin. It is a figure which shows the result of having verified the effect of the coating powder obtained by the manufacturing method of the coating powder shown as one Embodiment which concerns on this invention. It is the schematic block diagram of (a) powder coating apparatus shown as 2nd Embodiment which concerns on this invention, and (b) It is XX arrow sectional drawing of (a).

Explanation of symbols

10, 20 Powder coating apparatus 11, 21 Main body 12 Heating means 13a Plate with fins (stirring means)
13b Fin 15 Exhaust means

Claims (6)

A main body filled with the target powder and the base powder, a heating means for heating the inside of the main body, a stirring means for stirring the target powder and the base powder inside the main body, and And an evacuation means for evacuating the inside of the main body to make a vacuum state,
By heating the target powder and the base material powder while stirring the inside of the main body part while exhausting the inside of the main body part by the exhaust means, the surface of the base material powder is heated to the target powder. A powder coating apparatus characterized in that it is coated with a film containing at least one of the compositional components constituting the above. The powder coating apparatus according to claim 1, wherein
The agitation unit includes a drive unit that rotatably supports the main body portion about its axis, and the exhaust unit is directly connected to the main body portion from the outside so that the main body portion rotates about its axis. And a powder coating apparatus characterized by being configured to rotate together with the main body. The powder coating apparatus according to claim 2,
The powder coating apparatus, wherein the exhaust means is arranged coaxially with the axis of the main body. The powder coating apparatus according to any one of claims 1 to 3,
The powder coating apparatus according to claim 1, wherein the stirring means includes a fin-equipped plate in which fins extending radially outward from the radial center are provided on the surface of the disc. In the powder coating apparatus according to any one of claims 1 to 4,
The target powder is Mg powder or Mg-based alloy powder, and the base material powder is Fe powder or Fe-based alloy powder having an oxide film formed on the surface thereof. Coating equipment. A method for producing a coated powder, wherein the powder coating apparatus according to any one of claims 1 to 5 is used to coat the surface of the substrate powder with the coating to form a coated powder.

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