JP2018193281A - Production method of cylindrical ceramic sintered body - Google Patents

Abstract

To provide a production method of a cylindrical ceramic sintered body which has small deformation on sintering and has a stable shape after repeated firing.SOLUTION: The production method of a cylindrical ceramic sintered body by firing a cylindrical ceramic molding using a firing furnace includes: a molding step S1 of filling raw material powder in a cavity of a cylindrical molding die, followed by press-molding to give a cylindrical ceramic molding; an arrangement step S2 of arranging the cylindrical ceramic molding in the firing furnace; and a firing step S3 of firing the arranged cylindrical ceramic molding in the firing furnace to give a cylindrical ceramic sintered body. In the arrangement step S2, a plurality of first supporting members provided with a plurality of ridge parts on a top face are arranged on a furnace bottom of the firing furnace or on a bottom plate installed on the furnace bottom, a columnar second supporting member is placed on the first supporting members, and the cylindrical ceramic molding is placed standing straight on the second supporting member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a cylindrical ceramic sintered body used as a sputtering target in a magnetron rotary cathode sputtering apparatus.

  Conventionally, a flat plate is generally used as a sputtering target, but when this flat plate target is used for sputtering by a magnetron sputtering method, the use efficiency is 10% to 30%. Stay at%. This is because in magnetron sputtering, plasma is concentrated and collides with a specific part of a flat target by a magnetic field, causing a phenomenon in which erosion proceeds to a specific part of the target surface, and the deepest part reaches the backing plate in the target. This is because the life of the target is reached.

  In response to this problem, it has been proposed to increase the usage efficiency of the target by making the sputtering target cylindrical. This sputtering method uses a cylindrical sputtering target consisting of a cylindrical backing tube and a cylindrical target material formed on the outer periphery thereof, and a magnetic field generating facility and a cooling facility are installed inside the backing tube, Sputtering is performed while rotating the sputtering target. By using such a cylindrical sputtering target, the usage efficiency of the target can be increased to 60% to 70%. In addition, since this sputtering method is excellent in cooling efficiency, it is possible to increase the input power and form a film at a high film formation rate.

  As a material for such a cylindrical sputtering target, a metal material that can be easily processed into a cylindrical shape and has high mechanical strength is widely used. However, ceramic materials have low mechanical strength and are brittle. It has not yet spread.

  Ceramic cylindrical sputtering targets are sprayed by spraying ceramic powder on the outer periphery of a cylindrical backing tube, or filled with ceramic powder on the outer periphery of a cylindrical backing tube. The ceramic powder is generally manufactured by hot isostatic pressing (HIP) method or the like. However, the thermal spraying method has a problem that it is difficult to obtain a high-density target. Further, the HIP method has a problem that initial cost and running cost are high, peeling due to a difference in thermal expansion, and further, recycling of the target and the backing tube cannot be performed.

  On the other hand, in recent years, a cylindrical ceramic molded body is formed by a cold isostatic press (CIP) method, placed on a floor plate in a firing furnace, and fired to obtain a cylindrical ceramic sintered body. After that, a manufacturing method of a cylindrical sputtering target in which a cylindrical target material is obtained by grinding and joined to a cylindrical backing tube has been studied. According to this method, a high-density cylindrical sputtering target can be easily obtained at a relatively low cost in industrial scale production. In addition, since the backing tube can be easily removed from the cylindrical target material and recycled after sputtering, the cost of the cylindrical sputtering target can be reduced.

  However, in this method, when the cylindrical ceramic compact shrinks in the firing process, the cylindrical ceramic fired body is obtained by the frictional force acting between the lower end surface (the surface in contact with the base plate during firing) and the base plate. There is a problem that the combined body is greatly deformed. The cylindrical ceramic sintered body thus deformed not only becomes difficult to attach to the processing equipment in the subsequent grinding process, but also increases the amount of grinding and significantly reduces the productivity. Further, fine cracks (microcracks) and chips are likely to occur during processing, which causes cracks and chips in the cylindrical target material during bonding (bonding) to the backing tube and sputtering. In addition, the deformed ceramic sintered body may be defective due to insufficient machining allowance during processing.

  With respect to this problem, in Patent Document 1, a cylindrical ceramic molded body, which is an object to be fired, is mounted on a floor plate made of a plate-shaped ceramic molded body having sintering shrinkage equivalent to the cylindrical ceramic molded body. A method of placing and firing is proposed. Patent Document 1 describes that it is preferable to spread a bed powder such as alumina powder between a plate-shaped ceramic molded body and a cylindrical ceramic molded body.

  In Patent Document 2, a molded body support composed of a plurality of members that can move independently from a flat substrate (laying plate), and a force that intervenes between the substrate and the molded body support to prevent relative movement between the two. In a state where the cylindrical ceramic molded body is instructed by the molded body support using a firing jig provided with a sliding layer composed of a round bar or a spherical ceramic sintered body, Proposes how to do.

  However, in these methods, the sliding layer composed of a round bar or a spherical ceramic material has low stability, and is generated by slight inclination of the hearth, decomposition of atmospheric gas or organic components supplied into the furnace. Due to the influence of the air flow, there is a problem that the cylindrical ceramic molded body moves in the furnace together with the sliding layer and comes into contact with the furnace wall and the adjacent cylindrical ceramic molded body. In addition, the arrangement of the cylindrical ceramic molded body in the firing furnace is set so that the cylindrical ceramic molded body is uniformly fired in consideration of the influence of the decomposition product gas and the atmospheric gas supplied to the furnace. However, there is a problem that the cylindrical ceramic molded body is not uniformly fired by such movement.

  On the other hand, in Patent Document 3, a plurality of support members are arranged on the base plate having the air holes so that the longitudinal direction thereof coincides with the radial direction of the circle around the air holes, There has been proposed a method in which a cylindrical molded body is placed vertically thereon. According to this method, movement of the cylindrical molded body in the horizontal direction in the furnace is suppressed, and the coefficient of friction between the oxides is small, so that the support member slides on the floor plate, so that deformation is small and a homogeneous sintered body is obtained. It is said.

JP 2005-281862 A JP 2008-184337 A Japanese Patent Laid-Open No. 2006-88831

  In the method of manufacturing a cylindrical ceramic sintered body, if the firing furnace is repeatedly used, the sliding function cannot be sufficiently exhibited due to deformation or fixing of the support or the support member, and the The cylindrical ceramic molded body may be greatly deformed by the catch.

  In view of the above situation, the present invention is a cylindrical ceramic sintered body used as a sputtering target in a magnetron type rotary cathode sputtering apparatus, and has a stable shape even when repeatedly fired with little deformation during sintering. An object of the present invention is to provide a method for producing a shaped ceramic sintered body.

  In view of the above-described problems, the present inventor has made sincere studies on a method for suppressing deformation accompanying sintering shrinkage of a cylindrical ceramic sintered body. As a result, in the firing method in which the first support member having high-temperature durability is arranged radially and the slippage of the surface is used, the second support member has a plurality of protrusions on the upper surface. By arranging the support member of this and placing the molded body thereon, the contact area between the first and second support members is reduced, and the surface slips stably without the support members sticking together. The knowledge that can be obtained.

  That is, one aspect of the present invention is a method of manufacturing a cylindrical ceramic sintered body in which a cylindrical ceramic molded body is fired using a firing furnace, in which a raw material powder is filled in a cavity of a cylindrical forming mold and subjected to processing. A forming step of obtaining a cylindrical ceramic formed body by pressure forming, an arranging step of placing the cylindrical ceramic formed body in the firing furnace, and a cylinder obtained by firing the placed cylindrical ceramic formed body in the firing furnace And a first support having a plurality of ridges on the top surface of the floor in the firing furnace or a floor plate installed on the furnace floor in the firing step. A plurality of members are arranged, a columnar second support member is placed on the first support member, and the cylindrical ceramic molded body is placed in an upright state on the second support member.

  According to one aspect of the present invention, since the second support member contacts only with the ridges of the first support member, the frictional force is reduced, and the second support is provided according to the shrinkage during sintering of the molded body. The deformation of the sintered body can be reduced by sliding the member.

  At this time, in one aspect of the present invention, the first support member is arranged radially from the center of the cylindrical diameter of the cylindrical ceramic molded body, and the plurality of ridges are tangential to the outer periphery of the cylindrical ceramic molded body. And may be formed in parallel.

  The cylindrical ceramic molded body can be stably placed by arranging the first support members radially, and the ridges are formed parallel to the tangential direction of the outer periphery of the cylindrical ceramic molded body. Thus, the second support member is in a slippery direction.

  Further, at this time, in one embodiment of the present invention, the protruding strip portion may have a semicircular shape in cross-sectional view.

  When the convex strip portion of the first support member is semicircular in cross-sectional view, the contact area with the second support member is further reduced, and the second support member is more slidable.

  Further, at this time, in one embodiment of the present invention, the semicircular radius may be 0.5 mm or more and 5 mm or less.

  In the method for manufacturing a cylindrical ceramic sintered body according to an embodiment of the present invention, which will be described later, it is preferable that the radius of the semicircular ridges be in the above range because deformation during sintering is small.

  In one embodiment of the present invention, the protrusion may have a triangular shape in cross-sectional view.

  If the protrusions of the first support member are triangular in cross-sectional view, the contact area with the second support member is reduced, and the second support member is more slidable.

  In one embodiment of the present invention, the second support member has a columnar shape, and can be arranged radially so that the central axis of the column passes through the center of the cylindrical diameter of the cylindrical ceramic molded body.

  If the second support member is cylindrical, the contact portion with the first support member is almost point contact, and the second support member can be made more slippery by directing it in the contraction direction of the molded body. it can.

  At this time, in one embodiment of the present invention, the diameter of the columnar circle of the second support member may be 0.5 mm or more.

  In the method for manufacturing a cylindrical ceramic sintered body according to an embodiment of the present invention, which will be described later, it is preferable that the radius of the columnar circle of the second support member is in the above range because deformation during sintering is small.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the cylindrical ceramic sintered compact which can suppress the deformation | transformation at the time of sintering can be provided. Moreover, the cylindrical ceramic sintered body obtained by such a manufacturing method not only has high dimensional accuracy and can reduce the amount of grinding, but also when a cylindrical sputtering target is produced by joining with a backing tube. It is possible to effectively suppress the occurrence of cracks and chips. Therefore, according to the present invention, it is possible to provide a cylindrical sputtering target with a higher yield and lower cost than the conventional one, and its industrial significance is extremely high.

It is process drawing which shows the outline of the process in the manufacturing method of the cylindrical ceramic sintered compact concerning one Embodiment of this invention. It is a schematic sectional drawing for demonstrating arrangement | positioning of the cylindrical ceramic molded object in a baking furnace. It is a top view for demonstrating arrangement | positioning of the cylindrical ceramic molded object in a firing furnace. It is a schematic sectional drawing for demonstrating an effect | action of a support member at the time of a baking process when a cylindrical ceramic molded object shrink | contracts. It is a figure which shows the shape of the 1st supporting member which concerns on one Embodiment of this invention, (A) is a triangle when a protruding item | line part is a semicircle shape by sectional view, (B) is a triangle by sectional view. This is the case of shape.

Hereinafter, the manufacturing method of the cylindrical ceramic sintered body according to the present invention will be described in the following order with reference to the drawings. In addition, this invention is not limited to the following examples, In the range which does not deviate from the summary of this invention, it can change arbitrarily.
1. 1. Manufacturing method of cylindrical ceramic sintered body 1-1. Molding process 1-2. Arrangement process 1-3. Firing step Cylindrical ceramic sintered body

<1. Manufacturing method of cylindrical ceramic sintered body>
FIG. 1 is a process diagram showing an outline of a process in a method for producing a cylindrical ceramic sintered body according to an embodiment of the present invention. One embodiment of the present invention is a method for producing a cylindrical ceramic sintered body in which a cylindrical ceramic molded body is fired using a firing furnace, in which a raw material powder is filled in a cavity of a cylindrical forming mold and pressurized. A forming step S1 for forming a cylindrical ceramic formed body by molding, an arranging step S2 for disposing the cylindrical ceramic formed body in a firing furnace, and firing the cylindrical ceramic formed body in the firing furnace. A calcining step S3 for obtaining a bonded body, and in the disposing step S2, a plurality of first support members having a plurality of ridges on the upper surface are provided on the hearth in the calcining furnace or on the floor plate installed on the hearth. The columnar second support member is placed on the first support member, and the cylindrical ceramic molded body is placed on the second support member in an upright state.

  By adopting such a support member configuration, the contact area between the first and second support members is reduced, so that the frictional force is reduced and it is difficult to be affected by the sticking between the support members. And the knowledge that the deformation | transformation accompanying sintering shrinkage can be suppressed stably by this was acquired. The present invention has been completed based on these findings.

  Hereinafter, each step will be described in detail. In addition, although the manufacturing method of the cylindrical ceramic sintered compact which concerns on one Embodiment of this invention is not restrict | limited by the size of the cylindrical ceramic sintered compact to manufacture, below, mainly an outer diameter is 80 mm- A case where a cylindrical ceramic sintered body having a diameter of 200 mm, an inner diameter of 40 mm to 190 mm, and a total length of 50 mm to 500 mm is manufactured will be described as an example.

(1-1. Molding process)
The forming step S1 is a step in which the raw material powder is filled in the cavity of the cylinder forming mold and is pressure-formed by, for example, the CIP method to obtain a cylindrical ceramic formed body.

[Raw material powder]
In the present invention, the raw material powder is not particularly limited, and can be appropriately selected according to the composition of the target cylindrical sputtering target. For example, when obtaining a cylindrical sputtering target made of ITO (Indium Tin Oxide), indium oxide (In ₂ O ₃ ) powder and tin oxide (SnO) powder can be used as the raw material powder. Further, in order to obtain a cylindrical sputtering target made of AZO (Aluminium Zinc Oxide) as the raw material powder, aluminum oxide _(Al 2 _{O 3)} can be used powder and zinc oxide (ZnO) powder.

  It is possible to mix the raw material powder at a predetermined ratio and then mold it as it is. However, after mixing with pure water, a binder, a dispersing agent, etc., spray-dried to form a granulated powder and then into the cavity It is preferable to fill. The granulated powder has higher fluidity than the raw material powder and is excellent in filling property. For this reason, by using the granulated powder instead of the raw material powder, a high-density cylindrical ceramic molded body can be easily obtained even in industrial scale production.

[Molding]
Molding is generally CIP (Cold Isostatic Pressing) molding, but is not limited to CIP molding as long as a high-density cylindrical formed body can be obtained. In the case of CIP molding, a raw material powder or granulated powder is filled in a cavity, and then a cylinder forming mold is put into a CIP apparatus and pressure-molded. In order to prevent a pressure medium such as water from entering the mold, the cylinder forming mold may be vacuum-packed and put into the CIP apparatus. The holding pressure in CIP molding is preferably 98 MPa to 294 MPa. When the holding pressure is less than 98 MPa, the density of the obtained cylindrical ceramic molded body may not be sufficiently high. On the other hand, when the holding pressure exceeds 294 MPa, the load on the CIP device is excessively increased and the production cost is increased.

  In addition, it is preferable to set it as 1 minute-30 minutes, and, as for the time (holding time) hold | maintained by holding pressure, it is more preferable to set it as 3 minutes-10 minutes. If the holding time is less than 1 minute, the density of the obtained cylindrical ceramic molded body may not be sufficiently high. On the other hand, if the holding time exceeds 30 minutes, productivity will deteriorate.

(1-2. Arrangement process)
The placement step S2 is a step of placing the cylindrical ceramic molded body obtained in the forming step S1 in a firing furnace using the first support member and the second support member. In particular, in the present invention, a plurality of first support members having a plurality of protrusions on the upper surface are arranged on a hearth in a firing furnace or a floor plate installed on the hearth, and the first support member is placed on the first support member. A columnar second support member is placed, and the cylindrical ceramic molded body is placed in an upright state on the second support member.

[Arrangement]
FIG. 2 is a schematic cross-sectional view for explaining the arrangement of the cylindrical ceramic compact in the firing furnace, and FIG. 3 is a plan view for explaining the arrangement of the cylindrical ceramic compact in the firing furnace. . In the present invention, a plurality of first support members 15 having a plurality of ridges 16 on the upper surface are arranged on the hearth 11 in the firing furnace or the floor plate 13 installed on the hearth 11, and the first support member 15. The second support member 17 is placed on the second support member 17, and the cylindrical ceramic molded body 18 is placed on the second support member 17 in an upright state, followed by firing. In addition, when the vent hole 12 is provided in the hearth 11 or the like, a plurality of first support members 15 are arranged radially around the vent hole 12 of the hearth 11, and the second support member 17 is also the first support member 17. The cylindrical ceramic molded body 18 was placed upright on the support member 15 so that the center of the vent 12 of the hearth 11 and the cylindrical axis coincided with each other on the second support member 17. It may be placed in a state and fired. In addition, about the coincidence of the center of the vent hole 12 and the cylindrical axis, it is sufficient that they substantially coincide with each other, and the deviation (for example, about 10% to 30% with respect to the inner diameter of the cylindrical ceramic molded body) is sufficient. In the range where the effect of the present invention is sufficiently obtained, it is allowed.

  More specifically, first, a hearth 11 having a vent 12 is prepared. At this time, the vent 12 also serves as an atmosphere gas supply port. Next, the first support members 15 are arranged radially around the vent hole 12. At this time, for example, as shown in FIG. 3, it is preferable to arrange the plurality of first support members 15 at equal intervals in the circumferential direction. The first support member 15 has a plurality of ridges 16 on the upper surface. Here, the protrusion 16 is an elongated protrusion extending in the plane direction, and the shape thereof is not particularly limited as long as the contact area with the second support member 17 is reduced. A semi-cylindrical or triangular prism shape is preferred. Further, the interval between the protrusions 16 is not particularly limited as long as the second support member 17 does not fall in between, but it is preferably formed continuously as shown in FIG. 5 described later. . Moreover, it is preferable to arrange | position so that the center axis | shaft L1 direction of the protruding item | line part 16 of the 1st supporting member 15 may correspond with the tangent T direction of the circumferential direction of the cylindrical ceramic molded object 18 to be installed. In other words, the plurality of ridges 16 are preferably formed in parallel to the tangential T direction of the outer periphery of the cylindrical ceramic molded body 18. The tangent T on the outer periphery of the cylindrical ceramic molded body 18 is the intersection of the center line in the width direction of the first support member 15 (in the direction of the central axis L1 of the ridge 16) and the outer periphery of the cylindrical ceramic molded body 18. The tangent at.

  The second support member 17 has a columnar shape, and the central axis L2 of the second support member 17 extends through the vent 12 (or the cylindrical ceramic molded body 18) so as to straddle the thickness of the side wall of the cylindrical ceramic molded body 18. It arranges radially so that it may pass through the center C. The second support member 17 has a cylindrical shape, for example. Then, the cylindrical ceramic molded body 18 is placed upright and fired so that the center of the vent 12 and the cylindrical axis of the cylindrical ceramic molded body 18 coincide with each other. Depending on the size of the firing furnace, it is possible to arrange one or more cylindrical ceramic molded bodies 18. In this case, a plurality of vent holes 12 (atmosphere gas supply ports) are provided in the hearth 11. The first and second support members 15 and 17 are disposed around the respective vent holes. At this time, it is sufficient that the vent hole 12 has a space that does not allow the molded bodies 18 to interfere with each other.

In addition, when baking the several types of molded object from which a shape differs, you may install the base plate 13 on the hearth 11. The floor plate 13 is required to have high-temperature durability, its surface state does not easily change, and does not react with the cylindrical ceramic molded body 18 during firing. For this reason, the material is appropriately selected depending on the firing temperature of the cylindrical ceramic molded body 18, etc., and typical materials thereof are ceramic sintered bodies such as alumina (Al ₂ O ₃ ) and zirconia (ZrO ₂ ). Can be used. Further, the floor plate 13 is provided with a vent hole 14. The vent 14 is formed so that the upper surface of the floor plate 13 is disposed at the position where the molded body is disposed. Form as you can. Thereby, the center position of the vent hole 14 and the center position of the cylindrical ceramic molded body 18 can be easily matched by using the floor plate 13 corresponding to the type of the molded body. Further, when there is no vent hole, the cylindrical ceramic molded bodies 18 are appropriately arranged so as to be arranged at equal intervals according to the size of the firing furnace.

  FIG. 4 is a schematic cross-sectional view for explaining the operation of the support member when the cylindrical ceramic formed body 18 contracts in the firing step S3 described later. As described above, the first support member 15 having the plurality of ridges 16 on the upper surface and the columnar second support member 17 are placed, and the cylindrical ceramic molded body 18 is placed thereon and fired. The first support member 15 is in contact with the hearth 11 or the floor plate 13 in the planar shape of the first support member 15. The first support member 15 and the second support member 17 are configured such that the upper surface shape of the first support member 15 is a shape in which convex strips 16, for example, a semi-cylindrical column or a triangular column are continuous, and the second support member 17 is, for example, It is cylindrical. The central axis L1 direction of the semicircular cylinder or triangular prism of the upper surface shape of the first support member 15 is arranged so as to coincide with the circumferential tangent T direction of the cylindrical ceramic molded body 18 to be installed, The support members 17 of 2 are arranged radially so that the central axis L2 of the column passes through the center C of the vent 12 (or the cylindrical ceramic molded body 18) so as to straddle the thickness of the side wall of the cylindrical ceramic molded body 18. To do.

  For this reason, the center axis L1 direction of the semicircular cylinder or the triangular prism of the upper surface shape of the first support member 15 and the columnar center axis L2 of the second support member 17 intersect each other at a value close to a right angle. The first support member 15 and the second support member 17 are in point contact at the intersection. The second support member 17 and the cylindrical ceramic molded body 18 are such that the second support member 17 has a columnar shape, and the central axis L2 of the column is a vent so as to straddle the thickness of the side wall of the cylindrical ceramic molded body 18. 12 (or cylindrical ceramic molded body 18) is arranged in a radial manner so as to pass through the center C of the cylindrical ceramic molded body 18, so that line contact occurs. The second support member 17 has, for example, a columnar shape, and the second support member 17 bites into the bottom surface of the cylindrical ceramic molded body 18 by the weight of the cylindrical ceramic molded body 18 and is substantially on the surface. In contact.

  In the firing step S3 to be described later, when the cylindrical ceramic molded body 18 contracts, the cylindrical ceramic molded body 18 and the second support member 17, and the hearth 11 or the floor plate 13 and the first support member 15 are respectively surfaces. The first contact member 15 and the second support member 17 are in point contact with each other, and the friction force acting between them is extremely small compared to the friction force acting during the contact. For this reason, it becomes possible to slide and move while the cylindrical ceramic molded body 18 is placed between the first support member 15 and the second support member 17 at the time of sintering shrinkage of the cylindrical ceramic molded body 18. Deformation associated with sintering shrinkage can be greatly suppressed. In addition, the resistance value can be adjusted by changing the pitch of the top surface-shaped convex strips 16 (for example, a shape in which a semi-cylindrical column or a triangular column is continuous) of the first support member. It can be set appropriately according to the above.

The vent hole 12 is required to have a size that can ensure a sufficient supply amount of the atmospheric gas and that does not drop the support member that has been slid during firing. Therefore, it is preferable to adjust the range of the open area rate of the vent holes of ^{3cm 2 ~30cm} 2.

  Since the moving direction of the second support member 17 is limited in principle to the direction from the radially outer side to the center of the cylindrical ceramic molded body 18 (the arrow direction in FIG. 4), the slight inclination of the hearth 11 It is possible to prevent the cylindrical ceramic molded body 18 from moving and coming into contact with the furnace wall or the adjacent cylindrical ceramic molded body due to the influence of the airflow generated during firing.

[Support member]
The first support member 15 and the second support member 17 are required to have high-temperature durability, their surface states do not easily change, and do not react with the cylindrical ceramic formed body 18 during firing. For this reason, the material is appropriately selected depending on the firing temperature of the cylindrical ceramic molded body 18, etc., and typical materials thereof are ceramic sintered bodies such as alumina (Al ₂ O ₃ ) and zirconia (ZrO ₂ ). Can be used.

  The first support member 15 is required to mount and stably support the cylindrical ceramic molded body 18 via the second support member 17. For this reason, it is necessary to arrange the first support member 15 at three or more locations. 4 or more are more preferable, and 6 or more are more preferable. However, if there are too many installation places of the first support member 15, they interfere with each other when they are slid and are preferably suppressed to about 10 places or less.

  FIG. 5 is a view showing the shape of the first support member 15 according to the embodiment of the present invention. The upper surface shape of the first support member 15 is, for example, a shape in which a semi-cylindrical column or a triangular column is continuous. For example, as shown in FIG. 5A, the shape in which the semicylindrical portions are continuous may be a repetitive shape having a semicircular cross section. The semicircular repeating structure preferably has a semicircular radius of 0.5 mm or more and 5 mm or less. If the semicircular radius is less than 0.5 mm, it is difficult to obtain the effect of preventing sticking during firing. If the radius exceeds 5 mm, the distance between the point contacts of the first support member 15 and the second support member 17 may become long, and the second support member 17 may be deformed. When the compact 18 is sintered and contracted, the second support member 17 cannot move smoothly while the cylindrical ceramic compact 18 is placed.

  Further, the continuous shape of the semicylindrical body of the first support member 15 may not be a complete semicircle, but may be an elliptical shape. Alternatively, it may be a shape in which an arc having a length of 10% to 80% is repeated with respect to a circular circumferential length.

  In the case of a continuous shape of triangular prisms, for example, as shown in FIG. The angle θ of the apex is not particularly limited, but by setting it to 60 ° to 120 °, processing when the first support member 15 is manufactured becomes easy. The continuous triangular pitch is not less than 0.5 mm and not more than 5 mm, as in the semicircular shape. Further, the vertex portion may be subjected to R processing or C surface processing in order to prevent chipping in the vicinity of the vertex due to contact during handling or the like.

  The shape of the first support member 15 in the planar direction is not particularly limited, but if the second support member 17 has such a size that the second support member 17 does not slip off when sliding in the cylindrical diameter direction due to sintering shrinkage. Good. For example, a rectangular member having a width of 50 mm and a length of 60 mm can be used. Further, when a plurality of the first support members 15 are arranged, a trapezoidal shape with a short inner portion may be used so that the inner tip portion is not interfered.

  Such ridges 16 of the first support member 15 can be formed, for example, by grinding the upper surface of the plate-like member. Alternatively, a member whose upper surface is a semi-cylindrical or triangular prism may be arranged or embedded in a predetermined formwork. When the upper surface shape is a semi-cylindrical shape, for example, a plurality of cylindrical members are continuously arranged. A first support member 15 may be used in which the cylindrical members are connected to each other with a heat-resistant tape or the like.

  The second support members 17 are arranged on the first support member 15 in a radial pattern around the vent hole. The shape of the second support member 17 is not particularly limited as long as the contact area with the first support member 15 is reduced, and may be a prism, a polygonal column, etc. Etc. are particularly preferred.

  The length of the second support member 17 is longer than the length that can support the ceramic molded body, and may be a length that does not interfere with each other when sintered and contracted. The diameter of the second support member 17 may be 0.5 mm or more in consideration of the biting into the cylindrical ceramic molded body 18 when firing, and the upper limit is limited by the size of the first support member 15. For example, a round bar having a diameter of 3 mm and a length of 50 mm can be applied.

(1-3. Firing step)
The firing step S3 is a step of firing the cylindrical ceramic formed body arranged as described above using a firing furnace to obtain a cylindrical ceramic sintered body.

[Baking conditions]
The firing conditions of the cylindrical ceramic molded body should be appropriately selected according to the composition and size thereof, the characteristics of the firing furnace, etc., and are not particularly limited. In general, firing can be performed under the following conditions. it can.

a) Debinding step In the firing step, first, the organic components contained in the cylindrical ceramic molded body are heated from room temperature to a specific temperature (debinding temperature) over a certain period of time (debinding time). Need to be removed.

  The binder removal temperature at this time is preferably 300 ° C. to 600 ° C., more preferably 400 ° C. to 500 ° C. The binder removal time is preferably 50 hours to 300 hours, more preferably 100 hours to 300 hours. With such a binder removal temperature and binder removal time, the organic components contained in the cylindrical ceramic molded body can be sufficiently removed.

During the binder removal step, it is necessary to supply the atmospheric gas at a rate of 100 L / min to 600 L / min, preferably 200 L / min to 400 L / min per 1 m ³ of the furnace volume. The atmosphere may be air, oxygen, or any mixed gas thereof.

b) Sintering Step After the binder removal step, the furnace temperature is raised to the firing temperature, and this temperature is held for a certain period of time to sinter the cylindrical ceramic molded body.

  The firing temperature varies depending on the composition of the cylindrical ceramic molded body. For example, when indium oxide is the main component, the firing temperature is preferably set to 1200 ° C. to 1600 ° C., to obtain a high-density cylindrical ceramic sintered body. Therefore, it is more preferable to set it as 1300 to 1600 degreeC. On the other hand, when zinc oxide is the main component, it is preferably 1000 ° C. to 1400 ° C., and more preferably 1250 ° C. to 1350 ° C. from the same viewpoint. The holding time at the firing temperature is preferably 5 hours to 40 hours, more preferably 10 hours to 30 hours.

The atmosphere in the sintering stage varies depending on the composition of the cylindrical ceramic formed body, but depending on the composition, air, oxygen, or a mixed gas thereof is preferably 100 L / min to 600 L / min per 1 m ^{3 of} furnace volume. Supplies 200 L / min to 400 L / min.

<2. Cylindrical Ceramic Sintered Body>
The cylindrical ceramic sintered body obtained by the manufacturing method according to one embodiment of the present invention is obtained by firing uniformly while suppressing deformation of the cylindrical ceramic molded body. Such a cylindrical ceramic sintered body is characterized by excellent dimensional accuracy. More specifically, when a plurality of supporting members are used, the sintering shrinkage is freely contracted without being fixed at the time of sintering, so that the amount of deformation of the cylindrical shape is within 1.5 mm. Thus, the cylindrical ceramic sintered body obtained by the manufacturing method according to an embodiment of the present invention is a sintered body with excellent dimensional accuracy.

  The amount of deformation is based on the following measurement. The cylindrical ceramic sintered body obtained by the present invention has a deformation amount Δd (defined by the difference between the maximum value dmax and the minimum value dmin of the inner diameter d measured at four or more positions in the circumferential direction of the end surface on the ground side. = Dmax−dmin) is 1.5 mm or less. Here, the four positions in the circumferential direction determine the first inner diameter by a straight line passing through the center of the cylindrical ceramic sintered body, and sequentially determine the inner diameter on the straight line at the position where the phase is shifted by 45 °. What is necessary is just to measure, and when there are many measurement locations, the angle from which the phase shifts may be determined according to the number.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to a following example at all.

In the following Examples and Comparative Examples, the characteristics of the obtained cylindrical ceramic sintered body were evaluated, and the results are summarized in Table 1. As an evaluation method, a product obtained by firing 8 cylindrical ceramic compacts per fired batch was manufactured 5 times (40 in total), and the number of deformations exceeding 1.5 mm was counted. Regarding the raw materials and compositions shown in Table 1, 2AZO means that Al ₂ O ₃ is 2 wt%, ZnO is 98 wt%, and 10 ITO is SnO ₂ is 10 wt% and In ₂ O ₃ is 90 wt%. means. In addition, the flat plate of the first support member of the comparative example is a plate that looks rectangular when the cross section is viewed radially from the center of the cylindrical diameter.

Example 1
[Granulated powder]
In Example 1, first, the zinc oxide powder and the aluminum oxide powder were weighed so that the ratio of the aluminum oxide powder was 2% by mass. Pure water, polyvinyl alcohol (PVA) as a binder, and a dispersant are added so that the concentration of these raw material powders is 60% by mass, and they are mixed and crushed by a bead mill (manufactured by Ashizawa Finetech Co., Ltd.). As a result, a slurry was formed.

Next, this granulated powder was obtained by spray-drying this slurry with a spray dryer (made by Okawahara Kako Co., Ltd., ODL-20 type). When the tap density of this granulated powder was measured using a shaking specific gravity measuring device (KRS-409, manufactured by Kuramochi Scientific Instruments), it was confirmed to be 1.5 g / cm ³ .

[Molding process]
After filling this granulated powder into a cylindrical rubber mold, it is put into a cold isostatic press, and is molded by pressing with a holding pressure of 294 MPa and a holding time of 10 minutes, so that the outer diameter is 180 mm and the inner diameter is 150 mm. Eight cylindrical ceramic compacts having a total length of 350 mm were produced.

[Arrangement and firing process]
A normal pressure firing furnace having eight cylindrical ceramic compacts obtained in the molding step and having an inner diameter of 40 mm (opening area: 12.6 cm ² ) and eight atmosphere gas supply ports and a furnace volume of 0.5 m ³ It was placed in (Marusho Denki Co., Ltd.) and baked.

First, for each cylindrical ceramic molded body, an alumina flooring plate having an inner diameter of 30 mm (opening area: 7.1 cm ² ) and having a ventilation hole of 250 mm length, 250 mm width, and 5 mm thickness is prepared. Were installed on the hearth. Next, a first support member made of alumina having a shape in which a semi-cylinder having a width of 50 mm, a total length of 60 mm, and a top surface having a radius of 0.5 mm is continuously formed around the vent hole, the longitudinal direction of the first support member centered on the vent hole These were arranged radially at six locations so as to coincide with the radial direction of the circle centered on the vent hole. At this time, the first support member was arranged at approximately equal intervals so that the central axis direction of the semicircular column of the upper surface shape of the first support member was tangential to the circumferential direction of the cylindrical ceramic molded body. The second support member is a round rod made of alumina having a diameter of 3 mm and a length of 50 mm. Two second support members are provided for each first support member, 12 in total, with the vent hole as the center. The rods were arranged radially so that the central axis of the rod coincided with the radial direction of the circle centered on the vent hole. Subsequently, the cylindrical ceramic molded body was placed on the support member in an upright state so that the cylindrical axis coincided with the center of the vent hole on the second support portion.

In this state, the temperature is raised to 450 ° C. (debinder temperature) over 160 hours while circulating air at 300 L / min per 1 m ^{3 of} the furnace volume through the atmospheric gas supply port. The binder was removed by Then, while circulating oxygen at a volume of 300 L / min per 1 m ³ in the furnace, the temperature was raised to 1350 ° C., held at this temperature (firing temperature) for 20 hours, and the cylindrical ceramic compact was sintered, Eight cylindrical ceramic sintered bodies were produced. These cylindrical ceramic sintered bodies were taken out from the furnace, and the amount of deformation was measured.

  The above procedure was repeated 5 times to produce a total of 40 cylindrical ceramic sintered bodies. The number of deformation amounts of 1.5 mm or more at this time was counted.

(Example 2)
In Example 2, the shape of the upper surface of the first support member was a shape in which semicircular cylinders having a radius of 1.0 mm were continuous. Other than that, 40 cylindrical ceramic sintered bodies were produced in the same manner as in Example 1.

Example 3
In Example 3, the shape of the upper surface of the first support member was a shape in which a half cylinder with a radius of 1.5 mm was continuous, and the material was zirconia. The material of the second support member was also zirconia. Other than that, 40 cylindrical ceramic sintered bodies were produced in the same manner as in Example 1.

(Example 4)
In Example 4, the raw material powder was a mixed powder of indium oxide powder and tin oxide powder, the ratio of the tin oxide powder was 10% by mass, and the concentration of the raw material powder was 65% by mass to form a slurry. . A spherical granulated powder was obtained in the same manner as in Example 1 except that the cylindrical ceramic molded body had an outer diameter of 200 mm, an inner diameter of 160 mm, and a total length of 330 mm. The tap density of this granulated powder was 1.5 g / cm ³ . The cylindrical ceramic compacts were respectively installed on a hearth having a vent hole with an inner diameter of 30 mm (opening area: 7.1 cm ² ) via a support member. The binder removal temperature was 500 ° C., and the firing temperature was 1550 ° C. In addition, the upper surface shape of the first support member was a shape in which a half cylinder with a radius of 5.0 mm was continuous. The second supporting member was an alumina round bar having a diameter of 0.5 mm and a length of 50 mm. Other than that, 40 cylindrical ceramic sintered bodies were produced in the same manner as in Example 1.

(Example 5)
In Example 5, the shape of the upper surface of the first support member was a shape in which triangular prisms having isosceles triangles with apexes of 90 ° and isosceles sides of 2.0 mm were continuous. The second support member was an alumina round bar having a diameter of φ3.0 mm and a length of 50 mm. Other than that, 40 cylindrical ceramic sintered bodies were produced in the same manner as in Example 4.

(Comparative Example 1)
In Comparative Example 1, the top surface shape of the first support member was a planar shape, and the material was made of alumina. The second support member was an alumina square bar with a side of 3.0 mm and a length of 50 mm. Other than that, 40 cylindrical ceramic sintered bodies were produced in the same manner as in Example 1.

(Comparative Example 2)
In Comparative Example 2, the upper surface shape of the first support member was a planar shape, and the material was made of zirconia. The second support member was a square bar made of zirconia with a side of 3.0 mm and a length of 50 mm. Other than that, 40 cylindrical ceramic sintered bodies were produced in the same manner as in Example 1.

(Comparative Example 3)
In Comparative Example 3, the upper surface shape of the first support member was a planar shape, and the material was made of alumina. The second support member was made of alumina having a square of 3.0 mm on one side and a length of 50 mm. Other than that, 40 cylindrical ceramic sintered bodies were produced in the same manner as in Example 4.

  About the said Example and the comparative example, the deformation amount of 40 cylindrical ceramic sintered compacts was measured, respectively, and the number of the deformation amount of 1.5 mm or more at that time was counted. The results are shown in Table 1.

  From Table 1, it can be seen that in the examples, the number of deformation exceeding 1.5 mm is 0, the shape of the sintered body is good, and the dimensional accuracy is maintained even after repeated 5 times. In the comparative example, it can be seen that the frictional resistance is large and the amount of deformation may be large between the support members.

  Although one embodiment and each example of the present invention have been described in detail as described above, those skilled in the art will appreciate that many modifications can be made without departing from the novel matters and effects of the present invention. It will be easy to understand. Therefore, all such modifications are included in the scope of the present invention.

  For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term anywhere in the specification or the drawings. Moreover, the structure of the manufacturing method of a cylindrical ceramic sintered compact is not limited to what was demonstrated in one Embodiment and each Example of this invention, A various deformation | transformation implementation is possible.

DESCRIPTION OF SYMBOLS 11 Hearth, 12 (furnace floor) vent, 13 laying board, 14 (sill board) vent, 15, 15A, 15B 1st support member, 16, 16A, 16B Convex section, 17 2nd support member , 18 Cylindrical ceramic molded body

Claims (7)

A method for producing a cylindrical ceramic sintered body by firing a cylindrical ceramic molded body using a firing furnace,
A forming step of filling a raw material powder into a cavity of a cylindrical forming mold and press-molding to obtain a cylindrical ceramic molded body,
An arranging step of arranging the cylindrical ceramic molded body in the firing furnace;
A firing step of firing the arranged cylindrical ceramic compact in the firing furnace to obtain a cylindrical ceramic sintered body;
In the arranging step, a plurality of first support members having a plurality of convex portions on the upper surface are arranged on a hearth in the firing furnace or a floor plate installed on the hearth, and the first support member is placed on the first support member. A method for producing a cylindrical ceramic sintered body, wherein a columnar second support member is placed, and the cylindrical ceramic molded body is placed in an upright state on the second support member.   The first support member is arranged radially from the center of the cylindrical diameter of the cylindrical ceramic molded body, and the plurality of ridges are formed in parallel to the tangential direction of the outer periphery of the cylindrical ceramic molded body. The manufacturing method of the cylindrical ceramic sintered compact of description.   The method for manufacturing a cylindrical ceramic sintered body according to claim 1, wherein the protruding portion has a semicircular shape in cross-sectional view.   The method for producing a cylindrical ceramic sintered body according to claim 3, wherein the semicircular radius is 0.5 mm or more and 5 mm or less.   The method for manufacturing a cylindrical ceramic sintered body according to claim 1, wherein the protruding portion has a triangular shape in cross-sectional view.   The said 2nd support member is a column shape, and arrange | positions radially so that the center axis | shaft of this column may pass the cylindrical diameter center of the said cylindrical ceramic molded object. Manufacturing method of cylindrical ceramic sintered body.   The method for producing a cylindrical ceramic sintered body according to claim 6, wherein a diameter of a columnar circle of the second support member is 0.5 mm or more.

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