JP2019163886A - Sintering unit - Google Patents

Abstract

To provide a sintering unit suppressed in deformation of a sintering dish and usable over a long period.SOLUTION: A sintering unit comprises: a first sintering dish having a first face for placing a sintering object and a second face on the opposite side; and a support body supporting the first sintering dish. The support body abuts on the second face and supports at least a part of an outer peripheral part of the second face. The support body may be cylindrical, and an end facing the second face of the support body may abut on the outer peripheral part of the second face.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sintering unit, and more particularly to a sintering unit suitable for manufacturing a porous sintered body used for an electrolytic capacitor.

  In recent years, along with the reduction in size and weight of electronic devices, there has been a demand for small-sized and large-capacity high-frequency capacitors. As such a capacitor, development of a solid electrolytic capacitor having a small equivalent series resistance (ESR) and excellent frequency characteristics is being promoted. The solid electrolytic capacitor includes an anode body, a dielectric layer formed on the surface of the anode body, a solid electrolyte layer formed on the surface of the dielectric layer, and a cathode layer formed on the solid electrolyte layer. To do. As the anode body, a porous sintered body obtained by sintering valve action metal particles such as tantalum, niobium, and titanium is used.

  In general, a porous sintered body is obtained by pressure-molding valve action metal particles and a binder to obtain a porous molded body, and then firing the porous molded body under reduced pressure while the porous molded body is placed on a sintering dish. Manufactured by tying. Sintering is performed at 1000 ° C. or higher, for example. Therefore, the sintered dish is easily deformed by heat. Therefore, Patent Document 1 proposes that a plurality of concentric stringing ribs are provided on the sintering dish and a cross-shaped partition wall is provided.

JP 2003-13109 A

According to Patent Document 1, the difference in the heat distribution of the sintering pan is reduced, and thermal deformation is suppressed.
An object of the present invention is to further suppress thermal deformation of a sintered dish.

  A first aspect of the present invention includes a first sintering plate having a first surface on which a sintered object is placed and a second surface opposite to the first surface, and a support that supports the first sintering plate. , And the support is in contact with the second surface and supports at least a part of the outer peripheral portion of the second surface.

  According to the present invention, deformation of the sintered dish is suppressed, and long-term use is possible.

It is a perspective view which expands and shows a unit for sintering concerning one embodiment of the present invention. It is the top view which looked at the support body of the unit for sintering which concerns on one Embodiment of this invention, and the 1st sintering pan from the normal line direction of the 2nd surface. It is a perspective view of the support body concerning other one embodiment of the present invention. It is sectional drawing of the unit for sintering which concerns on one Embodiment of this invention. It is sectional drawing which shows the usage condition of the unit for sintering which concerns on one Embodiment of this invention.

  A porous sintered body used for an electrolytic capacitor is usually sintered in a state in which the porous molded body is placed on a sintering dish after pressure forming metal particles for pressure action to obtain a porous molded body. It is manufactured by doing. Sintering is performed, for example, in a state where a plurality of sintering dishes are stacked. The upper sintering plate is supported by a cylindrical body provided near the center of the lower sintering plate, as described in Patent Document 1, for example. At this time, the outer peripheral part of the upper sintering pan which is not supported is deformed by sagging downward by the load and heat generated by the porous molded body. As the deformation progresses, the sintered dish may break.

  Further, as will be described later, an opening is usually provided in the central portion of the sintering dish. A rod-shaped rod-shaped member is inserted into this opening, and the sintering dish is positioned. Therefore, many porous molded bodies will be arrange | positioned in the outer peripheral part of a sintering dish, and an outer peripheral part will deform | transform further easily.

  So, in this embodiment, the outer peripheral part of a sintering pan is supported from the downward direction by the support body which is a member different from a sintering pan. That is, the sintering unit according to the present embodiment supports a first sintering dish having a first surface on which a sintered object is placed and a second surface opposite to the first surface. A support body, and the support body abuts on the second surface and supports at least a part of the outer peripheral portion of the second surface. In this way, by supporting the outer peripheral portion of the sintering dish from below, deformation of the sintering dish due to the load from the object to be sintered and heating is suppressed. Furthermore, the freedom degree of the shape increases by making a support body a separate member from a sintering pan. Furthermore, the cleaning operation is facilitated by removing the support during cleaning of the sintered dish. Carbon derived from the binder contained in the object to be sintered is likely to adhere to the sintering dish. The carbon adhering to the sintering pan may cause recontamination of the object to be sintered and cause embrittlement of the sintering pan. Therefore, it is necessary to periodically clean the sintered dish.

  The outer peripheral portion of the second surface draws a plurality of arbitrary straight lines connecting the center point C and the outer edge of the second surface from the outer edge of the second surface, is on these straight lines, and the distance from the center point C is This is a region up to an annular line (similar to the outer shape of the second surface) formed by connecting a plurality of points that are ½ of a straight line. The center point C is the midpoint of the diameter of the circle when the second surface is circular, and the midpoint of the long and short diameters when the second surface is elliptical. When the second surface has a point-symmetric shape (for example, a rectangle) other than a circle and an ellipse, the center point C is an intersection of a plurality of diagonal lines.

  The support may be cylindrical. At least a part of the end portion facing the second surface of the cylindrical support is in contact with the outer peripheral portion of the second surface. Thereby, it becomes easy to support the outer peripheral part of a 2nd surface equally. When the end portion facing the second surface of the cylindrical support is viewed from the normal direction of the first surface, the shape may be similar to the outer shape of the second surface. For example, when the outer shape of the second surface is circular, the support is cylindrical. The cylindrical shape is not limited to the case of being completely closed, and there may be a gap or a spiral shape.

  The region where the object to be sintered is placed on the first surface of the first sintering pan may be flat. According to this embodiment, it is possible to suppress the deformation of the sintered dish without providing irregularities such as a stringed rib on the first surface. When the first surface is flat, the cleaning operation is further facilitated. That the first surface is flat means that there are no visible irregularities on the first surface.

  When the object to be sintered contains the first valve metal as a main component, it is preferable that the main component of the first sintering dish is also the first valve metal. This is to prevent contamination of the sintered object. A main component is a component which occupies 50 mass% or more of the total mass.

  The sintering unit may further include a second sintering pan. The second sintering dish is disposed so as to face the second surface of the first sintering dish via the support. There may be two or more second sintering dishes. In this case, a support is also interposed between the second sintered dishes. The second sintered dish may be the same type as or different from the first sintered dish. The unit for sintering may include a third sintering pan arranged to face the first surface of the first sintering pan via another support.

  Hereinafter, a sintering unit according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, although the case where the unit for sintering is provided with the 2nd sintering pan of the same type as the 1st sintering pan is illustrated, it is not limited to this. FIG. 1 is an exploded perspective view showing a unit for sintering according to the present embodiment. FIG. 2 is a plan view of the support for the sintering unit and the second sintering pan according to the present embodiment as viewed from the normal direction of the second surface. FIG. 3 is a perspective view of a support according to another embodiment. FIG. 4 is a cross-sectional view of the sintering unit according to the present embodiment. In the illustrated example, the object to be sintered is omitted and the rising portion is exaggerated for convenience.

  The sintering unit 100 includes a first sintering tray 10, a second sintering tray 30, and a support 20 interposed therebetween.

(First sintering dish)
The 1st sintering pan 10 has the 1st surface 10X in which a sintering target object (not shown) is mounted, and the 2nd surface 10Y on the opposite side. An opening 11 is provided near the center of the first surface 10X. In the sintering step, a rod-shaped rod-shaped member is inserted into the opening 11 and the first sintering dish 10 is positioned. A substantially cylindrical reinforcing member 12 for reinforcing the opening 11 is disposed around the opening 11. The reinforcing member 12 is joined to the first surface 10X by a rivet or the like.

  The first surface 10X and the second surface 10Y are substantially circular. However, the shape of the first surface 10X and the second surface 10Y is not limited to this, and may be a rectangle or any other shape. The diameters of the first surface 10X and the second surface 10Y are, for example, 10 cm to 25 cm. The distance between the first surface 10X and the second surface 10Y (the thickness of the first sintering pan 10) is, for example, 0.3 mm to 2 mm.

  A rising portion 10Z that rises from the second surface 10Y toward the first surface 10X is provided at the outer edge of the first surface 10X. Thereby, falling of a sintering target object is prevented and deformation | transformation of the 1st sintering pan 10 is further suppressed. The height of the rising portion 10Z from the first surface 10X is, for example, 3 mm to 10 mm. The rising portion 10Z is formed by, for example, pressing a plate material punched larger than the first surface 10X. At this time, the plate material of the rising portion 10Z may be doubled by pressing while folding the outer edge of the plate material.

  The object to be sintered is placed in a region other than the opening 11, the reinforcing member 12, and the rising portion 10Z of the first surface 10X. The said area | region (mounting area | region) in which a sintering target object is mounted is flat, and does not have visible unevenness | corrugations, such as a rib.

  As will be described later, a sintered dish mainly containing a valve metal is generally obtained by processing a plate material manufactured by a powder metallurgy method. The powder metallurgy method is a method in which metal particles are put into a mold and press-molded, and then sintered. Therefore, the obtained plate material has a grain boundary microscopically. The stringing rib is formed, for example, by punching the plate material to the same size as the sintered dish and further pressing. Since the plate material is mechanically bent by press working, the grain boundary is likely to spread. In a rib having a large grain boundary, grain boundary breakage is likely to occur due to heat or the like. Furthermore, when carbon enters the large grain boundaries, the brittleness of the ribs further proceeds. According to this embodiment, since such unevenness is not mechanically formed in the placement region of the first surface 10X, deformation of the sintered dish can be suppressed.

  The material of the 1st sintering pan 10 is not specifically limited, What is necessary is just to select suitably according to the component contained in a sintering target object. When the object to be sintered contains the first valve metal as a main component (a component occupying 50% or more of the total mass), the main component of the first sintering dish 10 is also the first valve metal in order to prevent contamination. Preferably there is. Examples of the first valve action metal include titanium (Ti), tantalum (Ta), niobium (Nb), and the like.

(Support)
The support 20 is disposed so as to face the second surface 10Y of the first sintering pan 10. The support body 20 is in contact with the second surface 10Y and supports at least a part of the outer peripheral portion of the second surface 10Y.

  The support 20 is cylindrical. However, the shape of the support is not limited to this, and may be a columnar shape, a wall shape, or a cylindrical shape other than a cylindrical shape (for example, a square tube). When using columnar or wall-shaped supports, two or more supports are arranged at positions corresponding to the outer peripheral portion of the second surface 10Y.

The outer diameter D ₂₀ (see FIG. 2) of the support 20 is not less than the radius D _{10b of} the second surface 10Y and not more than the diameter D _10a of the second surface 10Y. Thereby, the edge part (1st edge part) 20X which opposes the 2nd surface 10Y of the support body 20 contact | abuts to outer peripheral part 10Ya of the 2nd surface 10Y. In terms deformation suppressing effect is high in the first Shoyuisara 10, the outer diameter _{D 20} of the support 20, 75% of the diameter _{D 10a} of the second surface 10Y or more, may be not more than 100%. The opening 11 is provided in the central portion 10Yb of the second surface 10Y.

  The support 20 has a hole (see FIG. 4) formed by the support 20, the second surface 10 </ b> Y, and the third surface 30 </ b> X of the second sintering dish 30, and a hole (see FIG. 4). A connecting hole). Thereby, the exhaust resistance at the time of decompressing the space S is reduced. The shape of the connecting hole is not particularly limited, and may be circular or rectangular. For example, as shown in FIG. 3, a part of the connection hole 21 may be opened. The total area of the openings formed by the connecting holes 21 on the outer surface (outer surface) of the support 20 is, for example, 0.1% to 25% of the area of the outer surface.

  The material of the support 20 is not particularly limited, and may be appropriately selected according to the components contained in the sintered object. When the sintered object includes the first valve action metal as a main component, the main component of the support 20 is also preferably the first valve action metal. The distance between the outer surface and the inner surface of the support 20 (the thickness of the support 20) is, for example, 0.3 mm to 2 mm.

(Second sintering plate)
The second sintering dish 30 is disposed so as to face the second surface 10Y of the first sintering dish 10 with the support 20 interposed therebetween.
The second sintering dish 30 is the same type as the first sintering dish 10. However, the shape of the second sintering dish 30 may be different from that of the first sintering dish 10, and the second sintering dish 30 may be larger or smaller than the first sintering dish 10. .

  The 2nd sintering pan 30 has the 3rd surface 30X in which a sintering target object is mounted, and the 4th surface 30Y on the opposite side. An opening 31 is provided near the center of the third surface 30 </ b> X, and a reinforcing member 32 is disposed around the opening 31. An end portion (second end portion 20Y) opposite to the first end portion 20X of the support body 20 abuts on the outer peripheral portion of the third surface 30X. The outer peripheral portion of the third surface 30X can be defined similarly to the outer peripheral portion 10Ya of the second surface 10Y.

An outer edge of the third surface 30X is provided with a rising portion 30Z that rises from the fourth surface 30Y toward the third surface 30X, that is, toward the first sintering plate 10. As shown in FIG. 4, the height _{H 20} of the third surface 30X of the support 20 is greater than the height _{H 30} of the third surface 30X of the rising portion 30Z. Accordingly, the outer peripheral portion 10Ya of the first sintering pan 10 is supported by the support body 20 instead of the second sintering pan 30. Therefore, even when the second sintering tray 30 (particularly the rising portion 30Z) is deformed, the deformation of the outer peripheral portion 10Ya of the first sintering tray 10 is suppressed. The rising portion 30Z is usually formed by press working. Therefore, the rising portion 30 </ b> Z may slightly spread outward toward the first sintering dish 10. In this case, the rising portion 30Z is easily deformed so as to spread further outward.

The height H20 of the support ₂₀ is not particularly limited. The height _{H 20} of the support 20, for example, may be more than 110% of the height _{H 30} of the rising portion 30Z, may be 120% or more. From the viewpoint of productivity, it is preferable that the distance between the first sintering dish 10 and the second sintering dish 30 is not excessively wide. In this regard, the height _{H 20} of the support 20, may be 200% or less of the height _{H 30} of the rising portion 30Z, may be not more than 170%.

(Sintering object)
The object to be sintered is, for example, a porous molded body obtained by pressure-molding valve action metal particles. A part of the anode wire is embedded in the porous molded body. The remainder of the anode wire is led out from the porous molded body. After the porous molded body is sintered, it is used as an anode body of an electrolytic capacitor. The shape and size of the object to be sintered are not particularly limited, and are, for example, a rectangular parallelepiped having a side of 2 mm or less.

  The object to be sintered contains one or more valve action metal particles and a binder. The valve action metal particles may be an alloy composed of two or more metals. For example, an alloy containing a valve action metal and silicon, vanadium, boron, or the like can be used. A compound containing a valve metal and a typical element such as nitrogen may be used. The object to be sintered may contain a kind of valve metal (first valve metal) as a main component. A binder is not specifically limited, For example, an acrylic resin etc. are mentioned.

FIG. 5 is a cross-sectional view showing how the sintering unit 100 is used.
In FIG. 5, a third sintering dish 40 is further arranged on the opposite side of the first sintering dish 10 from the second sintering dish 30, and the support 20 is arranged between the sintering dishes. Yes. A lid 50 is disposed on the opposite side of the third sintering dish 40 from the first sintering dish 10, and the support 20 is also disposed between the third sintering dish 40 and the lid 50. The plurality of supports 20 may be the same type or different. Openings are provided in the vicinity of the center of the third sintering plate 40 and the lid 50, and the openings are reinforced by reinforcing members 42 and 52, respectively.

  The third sintering dish 40 may be the same type and the same material as the first sintering dish 10. The lid 50 has a size that covers at least the support 20 and is, for example, the same size as the surface of the third sintering plate 40 that faces the lid 50. The lid 50 may be made of the same material as the first sintering pan 10.

An example of a sintering process using the sintering unit 100 according to the present embodiment will be described.
First, the support 20 is disposed on the first surface 10 </ b> X of the first sintering dish 10. Next, the sintering object is placed on the first surface 10X. The object to be sintered may be placed between the support 20 and the rising portion 10Z. A plurality of objects to be sintered are placed at a time. Similarly, the support body 20 is arranged on the second sintering plate 30 and the third sintering plate 40, and the object to be sintered is placed thereon.

  Each sintering pan on which the object to be sintered is placed is stacked. As a result, the sintering unit 100 including the three sintering dishes is assembled. The interval between the sintering dishes is defined by the support 20 interposed between the sintering dishes. After covering the uppermost sintering dish (third sintering dish 40) with the lid 50, the rod-shaped member 60 is inserted into the openings formed in the respective sintering dishes and the lid 50. The position of each sintering dish is determined by the rod-shaped member 60.

The unit 100 for sintering is conveyed in a sintering furnace, for example in the state mounted in the base 70. FIG. The sintering furnace includes, for example, a binder removal chamber, a sintering chamber, a cooling chamber, and the like, and the sintering unit 100 is first transported to the binder removal chamber. In the binder removal chamber, the sintering unit 100 is heated at 300 to 500 ° C. under reduced pressure. Thereby, at least a part of the binder contained in the sintered object is removed. Next, the sintering unit 100 is transported to the sintering chamber. In the sintering chamber, the sintering unit 100 is heated at 1000 to 1500 ° C. under reduced pressure. Thereby, the valve action metal particles contained in a sintered object are sintered. Thereafter, the sintering unit 100 is transported and cooled, and then carried out of the sintering furnace.
By the above method, a porous sintered body is obtained.

  The unit for sintering according to the present invention is used, for example, for producing a porous sintered body used as an anode body of an electrolytic capacitor.

DESCRIPTION OF SYMBOLS 100: Unit for sintering 10: 1st sintering pan 10X: 1st surface 10Y: 2nd surface 10Ya: Outer peripheral part 10Yb: Center part 10Z: Rising part 11: Opening 12: Reinforcement member 20: Support body 20X: 1st End 20Y: Second end 21: Connection hole 30: Second sintering plate 30X: Third surface 30Y: Fourth surface 30Z: Rising portion 31: Opening 32: Reinforcement member 40: Third sintering plate 40Z: Rising Portion 41: Opening 42: Reinforcement member 50: Lid 52: Reinforcement member 60: Bar-shaped member 70: Base

Claims (7)

A first sintering dish having a first surface on which the object to be sintered is placed and a second surface opposite to the first surface;
A support for supporting the first sintering pan,
The support unit is a sintering unit that abuts on the second surface and supports at least a part of an outer peripheral portion of the second surface. The support is cylindrical,
2. The sintering unit according to claim 1, wherein an end portion of the support body facing the second surface is in contact with the outer peripheral portion of the second surface.   The unit for sintering according to claim 1 or 2, wherein a region where the object to be sintered is placed on the first surface is flat. The sintered object includes a first valve metal as a main component,
The unit for sintering according to any one of claims 1 to 3, wherein the first sintering pan includes the first valve metal as a main component. A second sintering dish disposed to face the first sintering dish via the support;
The second sintering dish includes a third surface facing the first sintering dish and a fourth surface on the opposite side.
The unit for sintering according to claim 1, wherein the support is in contact with the third surface. The outer edge of the third surface is provided with a rising portion that rises toward the first sintering pan,
The unit for sintering according to claim 5, wherein a height of the support from the third surface is larger than a height of the rising portion from the third surface.   The said support body is provided with the hole which connects the space formed by the said support body, the said 2nd surface, and the said 3rd surface, and the outer side of the said support body, For sintering of Claim 5 or 6 unit.

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