JP6266972B2 - Porous ceramic for firing jig, method for producing porous ceramic for firing jig, and cooling device - Google Patents
Porous ceramic for firing jig, method for producing porous ceramic for firing jig, and cooling device Download PDFInfo
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- JP6266972B2 JP6266972B2 JP2013258596A JP2013258596A JP6266972B2 JP 6266972 B2 JP6266972 B2 JP 6266972B2 JP 2013258596 A JP2013258596 A JP 2013258596A JP 2013258596 A JP2013258596 A JP 2013258596A JP 6266972 B2 JP6266972 B2 JP 6266972B2
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- refrigerant
- porous ceramic
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- pore diameter
- mold
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- 238000001816 cooling Methods 0.000 title claims description 81
- 238000010304 firing Methods 0.000 title claims description 39
- 238000004519 manufacturing process Methods 0.000 title claims description 28
- 239000011148 porous material Substances 0.000 claims description 112
- 239000003507 refrigerant Substances 0.000 claims description 76
- 239000002245 particle Substances 0.000 claims description 49
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- 238000007710 freezing Methods 0.000 claims description 25
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- 239000010935 stainless steel Substances 0.000 claims description 8
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
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- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 1
- UHVMMEOXYDMDKI-JKYCWFKZSA-L zinc;1-(5-cyanopyridin-2-yl)-3-[(1s,2s)-2-(6-fluoro-2-hydroxy-3-propanoylphenyl)cyclopropyl]urea;diacetate Chemical compound [Zn+2].CC([O-])=O.CC([O-])=O.CCC(=O)C1=CC=C(F)C([C@H]2[C@H](C2)NC(=O)NC=2N=CC(=CC=2)C#N)=C1O UHVMMEOXYDMDKI-JKYCWFKZSA-L 0.000 description 1
- 229910052845 zircon Inorganic materials 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
- C04B35/638—Removal thereof
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
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- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/62605—Treating the starting powders individually or as mixtures
- C04B35/62645—Thermal treatment of powders or mixtures thereof other than sintering
- C04B35/62655—Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
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- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
- C04B35/632—Organic additives
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- C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
- C04B38/007—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof characterised by the pore distribution, e.g. inhomogeneous distribution of pores
- C04B38/0074—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof characterised by the pore distribution, e.g. inhomogeneous distribution of pores expressed as porosity percentage
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- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
- C04B2235/54—Particle size related information
- C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
- C04B2235/5445—Particle size related information expressed by the size of the particles or aggregates thereof submicron sized, i.e. from 0,1 to 1 micron
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- C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
- C04B2235/602—Making the green bodies or pre-forms by moulding
- C04B2235/6023—Gel casting
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- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
- C04B2235/6567—Treatment time
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- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
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Description
開示の実施形態は、焼成治具用多孔質セラミックス、焼成治具用多孔質セラミックスの製造方法および冷却装置に関する。 The disclosed embodiments, the porous ceramics for firing jig, a method for manufacturing and cooling device of the porous ceramic for firing jig.
従来、気体または液体から不純物を除去するフィルタや吸着剤、自動車の排気ガス浄化用触媒の担持材料など、セラミックスに多くの気孔が形成された多孔質セラミックスは多岐に及ぶ用途で利用されている。 Conventionally, porous ceramics having many pores formed in ceramics, such as filters and adsorbents for removing impurities from gas or liquid, and support materials for automobile exhaust gas purification catalysts, have been used in various applications.
このような多孔質セラミックスの製造方法として、水溶性高分子の水溶液にセラミックス粒子を分散させた懸濁体（スラリー）をゲル化させた後、凍結させるゲル化凍結法を適用する方法が知られている（例えば、特許文献１参照）。 As a method for producing such porous ceramics, a method of applying a gelation freezing method in which a suspension (slurry) in which ceramic particles are dispersed in an aqueous solution of a water-soluble polymer is gelled and then frozen is known. (For example, refer to Patent Document 1).
しかしながら、特許文献１に記載された製造方法では、一方向に配向した気孔を有する多孔質セラミックスは得られるものの、気孔径のばらつきの少ない多孔質セラミックスを製造する点で改善の余地がある。 However, although the manufacturing method described in Patent Document 1 can obtain porous ceramics having pores oriented in one direction, there is room for improvement in terms of manufacturing porous ceramics with little variation in pore diameter.
実施形態の一態様は、上記に鑑みてなされたものであって、気孔径のばらつきが少ない焼成治具用多孔質セラミックス、焼成治具用多孔質セラミックスの製造方法および冷却装置を提供することを目的とする。 One aspect of the embodiments has been made in view of the above, and provides a porous ceramic for a firing jig with a small variation in pore diameter, a method for manufacturing the porous ceramic for a firing jig , and a cooling device. Objective.
実施形態に係る焼成治具用多孔質セラミックスは、平均気孔径が１〜５００μｍであり、気孔率が５０〜９９％であり、気孔径のばらつきが１３０％以下であり、気孔の平均アスペクト比が２．０以上であり、前記気孔が、互いに向かい合う一方の面から他方の面に向かって一方向に配向するように形成され、水平方向の寸法が１００００ｍｍ ２ 以上である。 Firing jig porous ceramics according to the embodiment, the average pore diameter of 1 to 500 [mu] m, porosity of 50 to 99% state, and are variations in pore diameter less 130%, an average aspect ratio of the pores There is at least 2.0, wherein the pores are formed so as oriented in one direction from one surface to the other surface facing each other, Ru der horizontal dimension 10000 mm 2 or more.
実施形態の一態様によれば、気孔径のばらつきが少ない焼成治具用多孔質セラミックス、焼成治具用多孔質セラミックスの製造方法および冷却装置を提供することができる。 According to one aspect of the embodiment, it is possible to provide a porous ceramic for a firing jig with little variation in pore diameter, a method for manufacturing the porous ceramic for a firing jig , and a cooling device.
以下、添付図面を参照して、本願の開示する焼成治具用多孔質セラミックス（以下、「多孔質セラミックス」と省略して記載する）、焼成治具用多孔質セラミックスの製造方法（以下、「多孔質セラミックスの製造方法」と省略して記載する）および冷却装置の実施形態を詳細に説明する。なお、以下に示す実施形態によりこの発明が限定されるものではない。 Hereinafter, with reference to the accompanying drawings, a porous ceramic for a firing jig disclosed herein (hereinafter abbreviated as “porous ceramic”) , a method for producing a porous ceramic for a firing jig (hereinafter, “ The abbreviated as “a manufacturing method of porous ceramics” and an embodiment of the cooling device will be described in detail. In addition, this invention is not limited by embodiment shown below.
実施形態に係る多孔質セラミックスは、ゲル化、凍結、乾燥、脱脂および焼成の各工程を含む製造方法により作製することができる点で従来の多孔質セラミックスと共通する。一方、実施形態に係る多孔質セラミックスの製造方法では、凍結工程において適用される冷却装置を変更することにより、従来とは異なる特長を有する多孔質セラミックスが形成される。以下では、まず、実施形態に係る多孔質セラミックスの製造方法について説明する。 The porous ceramic according to the embodiment is common to conventional porous ceramics in that it can be produced by a production method including steps of gelation, freezing, drying, degreasing and firing. On the other hand, in the method for producing porous ceramics according to the embodiment, porous ceramics having characteristics different from the conventional ones are formed by changing the cooling device applied in the freezing step. Below, the manufacturing method of the porous ceramics which concern on embodiment is demonstrated first.
図１は、実施形態に係る多孔質セラミックスの製造方法の概要を説明する説明図である。なお、図１では、上述した製造工程のうち、左から順にゲル化、凍結、および焼成の各工程を図示し、乾燥、脱脂の各工程に対応する図示は省略する。 Drawing 1 is an explanatory view explaining an outline of a manufacturing method of porous ceramics concerning an embodiment. In addition, in FIG. 1, each process of gelatinization, freezing, and baking is illustrated in order from the left among the manufacturing processes mentioned above, and illustration corresponding to each process of drying and degreasing is omitted.
まず、ゲル化工程について説明する。ゲル化工程は、セラミックス粒子１と、水溶性高分子２と、水３と、を含み、セラミックス粒子１が水溶性高分子２の水溶液中に均一に分散された懸濁体（スラリー）を、ここでは図示しない型に入れてゲル化させる工程である。懸濁体のゲル化により、セラミックス粒子１が水溶性高分子２の水溶液中に分散された状態で一時的に固定された構造体（ゲル化体）４が形成される。なお、懸濁体をゲル化させてゲル化体４を生成するための型の構成については図３Ａ、３Ｂを用いて後述する。 First, the gelation process will be described. The gelation step includes a suspension (slurry) including ceramic particles 1, a water-soluble polymer 2, and water 3, and the ceramic particles 1 are uniformly dispersed in an aqueous solution of the water-soluble polymer 2. Here, it is a step of gelation in a mold not shown. By the gelation of the suspension, a structure (gelated body) 4 is formed in which the ceramic particles 1 are temporarily fixed in a state where the ceramic particles 1 are dispersed in the aqueous solution of the water-soluble polymer 2. In addition, the structure of the type | mold for gelatinizing a suspension body and producing | generating the gelled body 4 is later mentioned using FIG. 3A and 3B.
次に、凍結工程について説明する。凍結工程は、ゲル化体４を冷却して凍結体６を生成する工程である。ゲル化体４を冷却すると、水溶性高分子２の水溶液から分離した水３が氷５に状態変化し、結晶構造を形成しながら成長する。その結果、セラミックス粒子１と、水溶性高分子２の水溶液がゲル化した部分（図示せず）と、結晶化した氷５の部分とを含む凍結体６が得られる。 Next, the freezing process will be described. The freezing step is a step of cooling the gelled body 4 to generate the frozen body 6. When the gelled body 4 is cooled, the water 3 separated from the aqueous solution of the water-soluble polymer 2 changes to ice 5 and grows while forming a crystal structure. As a result, a frozen body 6 including ceramic particles 1, a portion (not shown) in which an aqueous solution of the water-soluble polymer 2 is gelled, and a portion of crystallized ice 5 is obtained.
ここで、冷却装置１２をゲル化体４の下面７側に配置してゲル化体４を一方側から冷却すると、ゲル化体４中の水３が下面７側から凍結して氷５に状態変化し、この氷５の結晶が下面７側から上面８側に向かって成長しようとする。そして、氷５の結晶が成長する際には、セラミックス粒子１を移動させるのに十分な程度の押圧力が作用する。このため、氷５の結晶が成長しようとする方向にセラミックス粒子１が存在すると、ゲル化により一時的に固定されていたセラミックス粒子１は、成長する氷５の結晶の周囲に排除されるように移動する。 Here, when the cooling device 12 is arranged on the lower surface 7 side of the gelled body 4 and the gelled body 4 is cooled from one side, the water 3 in the gelled body 4 is frozen from the lower surface 7 side to be in the ice 5 state. The crystal of the ice 5 changes and tries to grow from the lower surface 7 side toward the upper surface 8 side. When the ice 5 crystal grows, a pressing force sufficient to move the ceramic particles 1 acts. For this reason, when the ceramic particles 1 are present in a direction in which the crystal of the ice 5 tends to grow, the ceramic particles 1 temporarily fixed by gelation are excluded around the crystal of the growing ice 5. Moving.
すなわち、冷却装置１２を用いてゲル化体４を一方向から冷却すると、一方向側から他方向側に柱状に成長した氷５の結晶を囲むようにセラミックス粒子１が再配列され、これによりセラミックス粒子１の分布に粗密が生じた凍結体６が生成されると考えられる。例えば、ゲル化体４を冷却するための冷媒を所望する温度で安定的に保持することができる冷却装置１２を適用すると、ゲル化体４を均質に凍結させることができる。すなわち、かかる冷却装置１２によりゲル化体４を冷却すると、下面７側から上面８側まで全面にわたり同程度の温度および速度で凍結が進み、同程度の大きさを有する複数の氷５の結晶が下面７側から上面８側に向かって成長した凍結体６が生成される。なお、かかる冷却装置１２の詳細な構成については、図２Ａ、２Ｂを用いて後述する。 That is, when the gelled body 4 is cooled from one direction using the cooling device 12, the ceramic particles 1 are rearranged so as to surround the crystal of the ice 5 grown in a column shape from one direction side to the other direction side. It is considered that a frozen body 6 in which the distribution of the particles 1 is coarse and dense is generated. For example, when the cooling device 12 that can stably hold the coolant for cooling the gelled body 4 at a desired temperature is applied, the gelled body 4 can be frozen uniformly. That is, when the gelled body 4 is cooled by the cooling device 12, freezing proceeds at the same temperature and speed from the lower surface 7 side to the upper surface 8 side, and a plurality of ice 5 crystals having the same size are formed. A frozen body 6 grown from the lower surface 7 side toward the upper surface 8 side is generated. A detailed configuration of the cooling device 12 will be described later with reference to FIGS. 2A and 2B.
次に、乾燥工程について説明する。乾燥工程は、凍結体６に成長した氷５を除去して気孔１０を生成する工程である。氷５が成長した凍結体６を、例えば真空乾燥により乾燥させると、氷５の結晶が昇華して消失し、代わりに気孔１０が形成される。すなわち、乾燥工程は、氷５を気孔１０に置換する工程である。 Next, the drying process will be described. The drying step is a step of generating pores 10 by removing the ice 5 grown on the frozen body 6. When the frozen body 6 on which the ice 5 has grown is dried, for example, by vacuum drying, the crystals of the ice 5 sublimate and disappear, and the pores 10 are formed instead. That is, the drying process is a process of replacing the ice 5 with the pores 10.
次に、脱脂工程について説明する。脱脂工程は、乾燥工程において気孔１０を生成した凍結体６から水溶性高分子２等の有機成分を除去する工程である。具体的には、セラミックス粒子１の種類に応じて、予め定められた温度条件下で水溶性高分子２等の有機成分を分解して除去する処理を実行する。 Next, the degreasing process will be described. The degreasing step is a step of removing organic components such as the water-soluble polymer 2 from the frozen body 6 that has generated the pores 10 in the drying step. Specifically, a process for decomposing and removing organic components such as the water-soluble polymer 2 under a predetermined temperature condition according to the type of the ceramic particle 1 is executed.
最後に、焼成工程について説明する。焼成工程は、氷５および水溶性高分子２等の有機成分が除去され、気孔１０が形成された凍結体６を焼成して多孔質セラミックス１１を作製する工程である。焼成により得られる多孔質セラミックス１１は、上述した乾燥工程において形成された気孔１０と、気孔１０を囲むようにセラミックス粒子１同士が結合して緻密化したセラミックス骨格９とを有する。 Finally, the firing process will be described. The firing step is a step of producing the porous ceramic 11 by firing the frozen body 6 in which the organic components such as the ice 5 and the water-soluble polymer 2 are removed and the pores 10 are formed. The porous ceramic 11 obtained by firing has pores 10 formed in the drying step described above and a ceramic skeleton 9 in which the ceramic particles 1 are bonded and densified so as to surround the pores 10.
このように、実施形態に係る多孔質セラミックス１１の製造方法によれば、冷却装置１２を用いることで凍結体６に生成された氷５の形状に基づき、下面７側から上面８側に向かって一方向に配向する筒状の気孔１０の周囲にセラミックス骨格９が形成された多孔質セラミックス１１が生成される。ここで、気孔１０が「一方向に配向する」とは、気孔１０の平均アスペクト比が２．０以上、好ましくは３．５以上であることをいう。なお、気孔１０の平均アスペクト比は、後述する実施例に記載する方法により測定することができる。 As described above, according to the method for manufacturing the porous ceramic 11 according to the embodiment, from the lower surface 7 side toward the upper surface 8 side based on the shape of the ice 5 generated in the frozen body 6 by using the cooling device 12. A porous ceramic 11 having a ceramic skeleton 9 formed around a cylindrical pore 10 oriented in one direction is generated. Here, “the pores 10 are oriented in one direction” means that the average aspect ratio of the pores 10 is 2.0 or more, preferably 3.5 or more. The average aspect ratio of the pores 10 can be measured by the method described in the examples described later.
ところで、上述した凍結工程において、従来、図８に示すような所望する温度に冷媒を冷却することができる冷却装置１２ａを適用し、ゲル化体を冷却して凍結体を生成する場合があった。しかしながら、従来の冷却装置１２ａは、気孔径のばらつきの少ない多孔質セラミックスを製造するという観点においては必ずしも十分な構成ではなかった。以下では、上述した凍結工程において好適に適用することができる冷却装置１２の一例について、従来の冷却装置１２ａと比較しながら説明する。 By the way, in the above-described freezing step, conventionally, there has been a case where a cooling device 12a capable of cooling the refrigerant to a desired temperature as shown in FIG. 8 is applied and the gelled body is cooled to generate a frozen body. . However, the conventional cooling device 12a is not necessarily a sufficient structure from the viewpoint of producing porous ceramics with less variation in pore diameter. Hereinafter, an example of the cooling device 12 that can be suitably applied in the above-described freezing step will be described in comparison with the conventional cooling device 12a.
まず、従来の冷却装置１２ａについて説明する。図８は、従来の冷却装置１２ａの構成の概要を示す図である。なお、図８および後述する図２Ａ、２Ｂでは、説明に必要な構成要素をごく模式的に示している。 First, the conventional cooling device 12a will be described. FIG. 8 is a diagram showing an outline of the configuration of the conventional cooling device 12a. In addition, in FIG. 8 and FIG. 2A and 2B mentioned later, the component required for description is shown typically.
また、説明を分かりやすくするために、図８および後述する図２Ａ、２Ｂには、鉛直上向きを正方向とし、鉛直下向きを負方向とするＺ軸を含む３次元の直交座標系を図示している。かかる直交座標系は、後述の説明に用いる他の図面でも示す場合がある。なお、図８における冷却装置１２ａの視点は、後述する図２Ｂにおける冷却装置１２の視点に対応している。 For easy understanding, FIG. 8 and FIGS. 2A and 2B to be described later illustrate a three-dimensional orthogonal coordinate system including a Z-axis in which the vertical upward direction is a positive direction and the vertical downward direction is a negative direction. Yes. Such an orthogonal coordinate system may also be shown in other drawings used in the following description. Note that the viewpoint of the cooling device 12a in FIG. 8 corresponds to the viewpoint of the cooling device 12 in FIG.
図８に示す冷却装置１２ａは、冷却槽１３ａと冷媒調整部１５ａとを備える。冷却槽１３ａと冷媒調整部１５ａとの間には、冷媒供給口２６および冷媒排出口２７が隣接して配置されており、冷却槽１３ａと冷媒調整部１５ａとの間を冷媒１７ａが循環するように流通できるよう構成されている。 The cooling device 12a shown in FIG. 8 includes a cooling tank 13a and a refrigerant adjusting unit 15a. A refrigerant supply port 26 and a refrigerant discharge port 27 are disposed adjacent to each other between the cooling tank 13a and the refrigerant adjustment unit 15a so that the refrigerant 17a circulates between the cooling tank 13a and the refrigerant adjustment unit 15a. It is configured so that it can be distributed.
また、冷却槽１３ａには、型２３ａに入ったゲル化体４ａが配置されている。そして、型２３ａの底部は、冷媒１７ａの液面と接触するように支持されている。 Moreover, the gelled body 4a contained in the mold 23a is arranged in the cooling tank 13a. And the bottom part of the type | mold 23a is supported so that the liquid level of the refrigerant | coolant 17a may be contacted.
ここで、冷媒調整部１５ａに配置されたプロペラ２０ａを回転させると、所望する温度となるように冷却された冷媒１７ａが冷媒供給口２６を介して冷媒調整部１５ａから冷却槽１３ａに供給され、ゲル化体４ａを下面７側から冷却する。ゲル化体４ａを冷却することで昇温された冷媒１７ａは、主として冷却槽１３ａの内壁に添うように向きを変えながらＸＹ平面方向に流動し、冷媒排出口２７を介して冷却槽１３ａから冷媒調整部１５ａに戻される。 Here, when the propeller 20a disposed in the refrigerant adjustment unit 15a is rotated, the refrigerant 17a cooled to a desired temperature is supplied from the refrigerant adjustment unit 15a to the cooling tank 13a through the refrigerant supply port 26. The gelled body 4a is cooled from the lower surface 7 side. The refrigerant 17a heated by cooling the gelled body 4a mainly flows in the XY plane direction while changing its direction so as to follow the inner wall of the cooling tank 13a, and the refrigerant 17a flows from the cooling tank 13a through the refrigerant discharge port 27. It is returned to the adjustment unit 15a.
かかる構成を有する冷却装置１２ａでは、上述したように冷媒１７ａは冷却槽１３ａの内壁に添うように水平方向に流動することで循環する。ここで、例えば冷媒供給口２６から冷却槽１３ａ内に向かって流動する冷媒１７ａは、冷媒１７ａの流れ方向が大きく屈曲する冷却槽１３ａの隅の部分で冷媒１７ａの流れに淀みが生じ易くなる。そして、冷却槽１３ａにおける冷媒１７ａの流れに淀みが生じると、冷媒１７ａの流速が遅くなることで局所的に凍結能力が減少し、結果として気孔径のばらつきが多い多孔質セラミックスが作製される懸念がある。 In the cooling device 12a having such a configuration, as described above, the refrigerant 17a circulates by flowing in the horizontal direction so as to follow the inner wall of the cooling tank 13a. Here, for example, the refrigerant 17a flowing from the refrigerant supply port 26 toward the inside of the cooling tank 13a is likely to stagnate in the flow of the refrigerant 17a at the corner of the cooling tank 13a where the flow direction of the refrigerant 17a is greatly bent. Then, when stagnation occurs in the flow of the refrigerant 17a in the cooling tank 13a, the freezing ability is locally reduced due to the slow flow rate of the refrigerant 17a, and as a result, porous ceramics with a large variation in pore diameter may be produced. There is.
一方、冷却槽１３ａ内での冷媒１７ａの淀みを防止するためにプロペラ２０ａの回転速度を変更して冷媒１７ａの流速を上昇させると、冷媒１７ａが波打つことで冷媒１７ａの液面に高低差が生じ易くなる。そして、冷媒１７ａの液面に高低差が生じると、例えば型２３ａの底部と冷媒１７ａの液面とが一時的に非接触となることでゲル化体４ａを均質に冷却することができず、結果として気孔径のばらつきが多い多孔質セラミックスが作製される懸念がある。 On the other hand, when the rotational speed of the propeller 20a is changed to increase the flow rate of the refrigerant 17a in order to prevent the refrigerant 17a from stagnation in the cooling tank 13a, the refrigerant 17a undulates and the liquid level of the refrigerant 17a changes. It tends to occur. And when the level difference occurs in the liquid level of the refrigerant 17a, for example, the gelled body 4a cannot be uniformly cooled by temporarily contacting the bottom of the mold 23a and the liquid level of the refrigerant 17a, As a result, there is a concern that porous ceramics having a large variation in pore diameter may be produced.
このように、従来の冷却装置１２ａを適用すると、ゲル化体４ａを適切に冷却することができずに気孔径のばらつきが多い多孔質セラミックスが作製される懸念があった。かかる気孔径のばらつきは、淀みが生じ易い冷却槽１３ａの隅の部分にまでゲル化体４ａが配置される、例えば冷却槽１３ａの寸法に相当するような比較的大型の型２３ａを使用する場合において特に顕著となる。 Thus, when the conventional cooling device 12a was applied, there was a concern that the gelled body 4a could not be appropriately cooled and porous ceramics having a large variation in pore diameters were produced. Such a variation in pore diameter is caused when the gelled body 4a is disposed up to the corner of the cooling tank 13a where stagnation easily occurs, for example, when a relatively large mold 23a corresponding to the size of the cooling tank 13a is used. In particular.
これに対し、実施形態に係る冷却装置１２では、冷却槽１３全体にわたり冷媒１７を適切に流動させることができ、ゲル化体４を均質に冷却させることができる。このため、冷却槽１３内に配置可能ないかなる大きさの型２３を使用してゲル化体４を凍結させる場合であっても、気孔径のばらつきが少ない多孔質セラミックス１１を作製することができる。かかる冷却装置１２の一例について、図２Ａ、２Ｂを用いて以下に説明する。 On the other hand, in the cooling device 12 according to the embodiment, the refrigerant 17 can be appropriately flowed over the entire cooling tank 13, and the gelled body 4 can be cooled uniformly. For this reason, even when the gelled body 4 is frozen using a mold 23 of any size that can be placed in the cooling bath 13, the porous ceramic 11 having a small variation in pore diameter can be produced. . An example of the cooling device 12 will be described below with reference to FIGS. 2A and 2B.
図２Ａは、実施形態に係る冷却装置１２の構成の概要を示す側断面図、図２Ｂは、図２Ａに示す冷却装置１２のＡ−Ａ’線断面図である。 FIG. 2A is a side cross-sectional view illustrating an outline of the configuration of the cooling device 12 according to the embodiment, and FIG. 2B is a cross-sectional view taken along line A-A ′ of the cooling device 12 illustrated in FIG. 2A.
実施形態に係る冷却装置１２は、冷却槽１３と、冷媒調整部１５と、仕切板２５とを備える。ゲル化体４が入った型２３は、冷却槽１３の上方に開口する開口部分から底板２１がゲル化体支持部１４ａ，１４ｂに支持されるように配置される。ここで、凍結体６を適切に生成することができる型２３の一例について、図３Ａ、３Ｂを用いて説明する。 The cooling device 12 according to the embodiment includes a cooling tank 13, a refrigerant adjustment unit 15, and a partition plate 25. The mold 23 containing the gelled body 4 is arranged so that the bottom plate 21 is supported by the gelled body support portions 14a and 14b from the opening portion opened above the cooling tank 13. Here, an example of the mold | type 23 which can produce | generate the frozen body 6 appropriately is demonstrated using FIG. 3A and 3B.
図３Ａは、実施形態に係る多孔質セラミックス１１の製造方法における上述したゲル化および凍結の各工程において好適に使用することができる型２３の構成の概要を示す側断面図、図３Ｂは、図３Ａに示す型２３のＢ−Ｂ’線断面図である。 FIG. 3A is a side sectional view showing an outline of the configuration of a mold 23 that can be suitably used in each of the steps of gelation and freezing described above in the method of manufacturing the porous ceramics 11 according to the embodiment. FIG. It is BB 'sectional view taken on the line of the type | mold 23 shown to 3A.
図示されるように、型２３は底板２１および周壁２２を備える。底板２１は、周壁２２の端面と密着してゲル化体４の下面７の形状を規定する内面２１ａと、ゲル化体支持部１４ａ，１４ｂ上に配置されて冷媒１７に接触する外面２１ｂとを有する。一方、周壁２２は、ゲル化体４の外周形状を規定する内周面２２ａを有する。そして、底板２１の外面２１ｂが冷媒１７に接触または浸漬することにより、ゲル化体４は底板２１を介して下面７から順次冷却されて凍結体６となる。 As illustrated, the mold 23 includes a bottom plate 21 and a peripheral wall 22. The bottom plate 21 has an inner surface 21 a that is in close contact with the end surface of the peripheral wall 22 and defines the shape of the lower surface 7 of the gelled body 4, and an outer surface 21 b that is disposed on the gelled body support portions 14 a and 14 b and contacts the refrigerant 17. Have. On the other hand, the peripheral wall 22 has an inner peripheral surface 22 a that defines the outer peripheral shape of the gelled body 4. Then, when the outer surface 21 b of the bottom plate 21 contacts or is immersed in the refrigerant 17, the gelled body 4 is sequentially cooled from the lower surface 7 via the bottom plate 21 to become the frozen body 6.
ここで、型２３の材質は、ステンレス鋼、鉄、銅またはアルミニウムであり、好ましくはステンレス鋼である。また、底板２１および周壁２２の材質は同じであっても良く、また異なっていても良い。 Here, the material of the mold 23 is stainless steel, iron, copper or aluminum , preferably stainless steel. Moreover, the material of the baseplate 21 and the surrounding wall 22 may be the same, and may differ.
また、底板２１の厚みｔ１および周壁２２の厚みｔ２は同じであっても良く、また異なっていても良いが、実用上、厚みｔ１およびｔ２は同じであることが好ましい。また、厚みｔ１およびｔ２は２ｍｍ以上であることが好ましく、実用上２〜１０ｍｍが好ましい。底板２１の厚みｔ１が２ｍｍ未満だと、冷媒１７の温度に局所的に高低差があった場合には、この冷媒の「温度ムラ」がゲル化体４にダイレクトに伝導されてしまい、ゲル化体４を均質に冷却させることができない懸念がある。また、周壁２２の厚みｔ２が２ｍｍ未満だと、周壁２２に近いゲル化体４の外側と周壁２２から遠いゲル化体４の外側とで冷却速度にばらつきが生じ、ゲル化体４を均質に冷却させることができない懸念がある。 Further, the thickness t 1 of the bottom plate 21 and the thickness t 2 of the peripheral wall 22 may be the same or different, but in practice, the thicknesses t 1 and t 2 are preferably the same. It is preferable that the thickness t 1 and t 2 is 2mm or more, practically 2~10mm are preferred. If the thickness t 1 of the bottom plate 21 is less than 2 mm, if there is a local height difference in the temperature of the refrigerant 17, the “temperature unevenness” of this refrigerant is directly conducted to the gelled body 4, and the gel There is a concern that the chemicalized body 4 cannot be cooled uniformly. When the thickness t2 of the peripheral wall 22 is less than 2 mm, the cooling rate varies between the outside of the gelled body 4 close to the peripheral wall 22 and the outside of the gelled body 4 far from the peripheral wall 22, and the gelled body 4 is homogeneous. There is a concern that it cannot be cooled down.
また、ゲル化体４の大きさは冷却槽１３内に収容できる大きさであれば制限はないが、より好ましくは水平方向の寸法が１３５ｍｍ×１３５ｍｍ以上１０００ｍｍ×１０００ｍｍ以下、すなわち面積換算で１８２２５ｍｍ２以上１０６ｍｍ２以下とされる。かかる場合、焼成後に得られる多孔質セラミックス１１の水平方向の寸法は概ね１００ｍｍ×１００ｍｍ以上７４０ｍｍ×７４０ｍｍ以下、すなわち面積換算で１０４ｍｍ２以上５４７６００ｍｍ２以下となる。ゲル化体４の水平方向の寸法が１８２２５ｍｍ２未満、あるいは焼成後の多孔質セラミックス１１の水平方向の寸法が１０４ｍｍ２未満だと、従来の冷却装置１２ａを適用して凍結体６を生成した場合との気孔径のばらつきの差異が顕著に表れないことがある。一方、ゲル化体４の水平方向の寸法が１０６ｍｍ２超、あるいは焼成後の多孔質セラミックス１１の水平方向の寸法が５４７６００ｍｍ２超だと、冷却装置１２における攪拌機構の能力上の制約により、ゲル化体４の下面側を均質に冷却させることができない懸念がある。 The size of the gelled body 4 is not limited as long as it can be accommodated in the cooling bath 13, but more preferably the horizontal dimension is 135 mm × 135 mm or more and 1000 mm × 1000 mm or less, that is, 18225 mm 2 in terms of area. It is 10 6 mm 2 or less. In this case, the horizontal dimensions of the porous ceramic 11 obtained after firing is approximately 100 mm × 100 mm or more 740mm × 740mm or less, that is, 10 4 mm 2 or more 547600Mm 2 or less in area terms. When the horizontal dimension of the gelled body 4 is less than 18225 mm 2 or the horizontal dimension of the fired porous ceramic 11 is less than 10 4 mm 2 , the frozen body 6 is generated by applying the conventional cooling device 12a. In some cases, the difference in the pore size variation from that of the case does not appear remarkably. On the other hand, if the horizontal dimension of the gelled body 4 exceeds 10 6 mm 2 or the horizontal dimension of the porous ceramics 11 after firing exceeds 547600 mm 2 , due to restrictions on the ability of the stirring mechanism in the cooling device 12 There is a concern that the lower surface side of the gelled body 4 cannot be cooled uniformly.
図２Ａ、２Ｂに戻り、実施形態に係る冷却装置１２についてさらに説明する。冷媒調整部１５には、シャフト１９の下端部分に取り付けられたプロペラ２０が冷媒１７に浸漬するように配置されている。 2A and 2B, the cooling device 12 according to the embodiment will be further described. A propeller 20 attached to the lower end portion of the shaft 19 is disposed in the refrigerant adjustment unit 15 so as to be immersed in the refrigerant 17.
また、仕切板２５は、冷媒調整部１５内のシャフト１９およびプロペラ２０と干渉しないように構成されている。仕切板２５はまた、略水平方向に延びるように構成されており、仕切板２５を挟んで上下で冷媒１７をそれぞれ略水平方向に流通させることができる。かかる仕切板２５は冷却槽１３内に終端２５ａを有し、仕切板２５は冷却槽１３の全体を覆うことなく冷却槽１３内で途切れることにより一部が開口している。 Further, the partition plate 25 is configured not to interfere with the shaft 19 and the propeller 20 in the refrigerant adjustment unit 15. The partition plate 25 is also configured to extend in a substantially horizontal direction, and the refrigerant 17 can be circulated in a substantially horizontal direction above and below the partition plate 25. The partition plate 25 has a terminal end 25 a in the cooling tank 13, and the partition plate 25 is partially opened by being interrupted in the cooling tank 13 without covering the entire cooling tank 13.
制御部２４により駆動制御されたモータ１８がプロペラ２０をシャフト１９と共に回転させると、冷媒１７は仕切板２５の上下を互いに異なる方向に流動する。かかる冷媒１７は、冷凍機１６に接続された図示しないフィンを介して熱交換され、所望する温度で保持されつつ仕切板２５の上側を通じて冷却槽１３に順次送られる。そして、冷却槽１３に送られた冷媒１７は、仕切板２５の終端２５ａよりも奥、すなわち冷媒調整部１５から離れた部分で鉛直下向きに潜り込むように流動する。その後、冷媒１７は仕切板２５の下側を通じて冷媒調整部１５側に送られることで冷却装置１２内を循環することができる。 When the motor 18 that is driven and controlled by the control unit 24 rotates the propeller 20 together with the shaft 19, the refrigerant 17 flows in different directions above and below the partition plate 25. The refrigerant 17 is heat-exchanged through fins (not shown) connected to the refrigerator 16 and sequentially sent to the cooling tank 13 through the upper side of the partition plate 25 while being held at a desired temperature. Then, the refrigerant 17 sent to the cooling bath 13 flows so as to sink vertically downward at a position farther from the end 25 a of the partition plate 25, that is, at a portion away from the refrigerant adjusting unit 15. Thereafter, the refrigerant 17 can be circulated through the cooling device 12 by being sent to the refrigerant adjusting unit 15 side through the lower side of the partition plate 25.
かかる構成を備える冷却装置１２によれば、冷却槽１３の全面にわたり、型２３が配置された冷媒１７の表層部分において冷媒１７の液面を波打たせたり冷媒１７の流動を淀ませたりすることなく、冷媒１７を絶えず流動させることができる。そして、ゲル化体支持部１４ａ，１４ｂ上に載置されたゲル化体４は型２３の底板２１側から均質に冷却される。ここで、「冷媒１７の表層部分」とは、冷媒１７の液面を含み、型２３の底板２１が浸漬した部分よりも上方をいう。 According to the cooling device 12 having such a configuration, the liquid surface of the refrigerant 17 is waved or the flow of the refrigerant 17 is stiffened in the surface layer portion of the refrigerant 17 in which the mold 23 is arranged over the entire surface of the cooling tank 13. The refrigerant 17 can flow constantly. The gelled body 4 placed on the gelled body support portions 14a and 14b is uniformly cooled from the bottom plate 21 side of the mold 23. Here, the “surface layer portion of the refrigerant 17” includes the liquid surface of the refrigerant 17 and is above the portion where the bottom plate 21 of the mold 23 is immersed.
なお、冷却装置１２で使用する冷媒１７としては、凝固温度が低く、ゲル化体４を凍結させるために所望する温度まで液状であるものであれば特に制限はない。具体的には、エタノール、メタノール、イソプロピルアルコール、アセトン、エチレングリコールなどが挙げられるが、これらに限定されない。なお、これらの冷媒１７を単独で、あるいは複数種類併用し、また必要に応じて水と混和させて使用することができる。 The refrigerant 17 used in the cooling device 12 is not particularly limited as long as it has a low solidification temperature and is liquid up to a desired temperature for freezing the gelled body 4. Specific examples include, but are not limited to, ethanol, methanol, isopropyl alcohol, acetone, ethylene glycol, and the like. In addition, these refrigerant | coolants 17 can be used individually or in combination of multiple types, and can be mixed with water as needed.
また、冷媒１７の液量は、底板２１が冷媒１７の液面に接触し、あるいは底板２１の一部または全体が冷媒１７に浸漬するように調整される。なお、ゲル化体４のより均質な凍結の観点から、冷媒１７の液面は周壁２２には接触しない、すなわち底板２１の内面２１ａの高さを超える高さにまで到達しない高さとなるように調整されることが好ましい。 In addition, the liquid amount of the refrigerant 17 is adjusted so that the bottom plate 21 is in contact with the liquid surface of the refrigerant 17 or a part or the whole of the bottom plate 21 is immersed in the refrigerant 17. From the viewpoint of more uniform freezing of the gelled body 4, the liquid level of the refrigerant 17 does not contact the peripheral wall 22, that is, does not reach a height exceeding the height of the inner surface 21 a of the bottom plate 21. It is preferable to adjust.
実施形態に係る多孔質セラミックス１１の製造方法において、セラミックス粒子１は、焼成工程において適切に焼成可能なものであれば特に制限はない。具体的には、例えば、ジルコニア、アルミナ、シリカ、チタニア、炭化ケイ素、炭化ホウ素、窒化ケイ素、窒化ホウ素、コーディエライト、ハイドロキシアパタイト、サイアロン、ジルコン、チタン酸アルミニウム、およびムライトのうち１種以上をセラミックス粒子１として適用できるが、これらに限定されない。また、例えば、アルミナおよびシリカを適用してムライトを作製したり、ジルコニアおよびアルミナを適用して複合体を作製したりといった、所望する特性に応じて複数のセラミックス粒子１を組み合わせて使用することができる。 In the method for manufacturing the porous ceramic 11 according to the embodiment, the ceramic particle 1 is not particularly limited as long as it can be appropriately fired in the firing step. Specifically, for example, one or more of zirconia, alumina, silica, titania, silicon carbide, boron carbide, silicon nitride, boron nitride, cordierite, hydroxyapatite, sialon, zircon, aluminum titanate, and mullite are used. Although applicable as the ceramic particle 1, it is not limited to these. Further, for example, a plurality of ceramic particles 1 may be used in combination according to desired properties, such as making mullite by applying alumina and silica, or making a composite by applying zirconia and alumina. it can.
また、セラミックス粒子１は、実用上、平均粒径が１００μｍ以下のものが好ましい。セラミックス粒子１の平均粒径が１００μｍを超えると、所望する多孔質セラミックス１１の形状や大きさによってはセラミックス粒子１の適切な焼成が困難な場合がある。ここで、「平均粒径」とは、レーザ回折式粒度分布測定装置（湿式法）において、球相当径に換算した体積基準の粒度分布に基づいて得られたメジアン径（ｄ５０）を指す。なお、同じ結果を得られるものであれば、測定方法に制限はない。 The ceramic particles 1 preferably have an average particle size of 100 μm or less in practice. When the average particle size of the ceramic particles 1 exceeds 100 μm, it may be difficult to appropriately fire the ceramic particles 1 depending on the shape and size of the desired porous ceramic 11. Here, the “average particle diameter” refers to a median diameter (d50) obtained based on a volume-based particle size distribution converted into a sphere equivalent diameter in a laser diffraction particle size distribution measuring apparatus (wet method). Note that there is no limitation on the measurement method as long as the same result can be obtained.
懸濁体中のセラミックス粒子１の配合量は、１〜５０ｖｏｌ％の範囲が好ましく、より好ましくは１〜３０ｖｏｌ％である。セラミックス粒子１の配合量が１ｖｏｌ％未満だと、例えば乾燥工程において形状を維持することができない場合があり、また、所望の強度を有する多孔質セラミックス１１を製作することが困難となる。また、セラミックス粒子１の配合量が５０ｖｏｌ％を超えると、得られる多孔質セラミックス１１は気孔率が低くなり、多孔体として所望される特徴を十分に示さない場合がある。ここで、「気孔率」とは、ＪＩＳＲ１６３４：２００８に規定する手法に基づき、アルキメデス法により得られた値をいう。かかる測定では、閉気孔は考慮されないため、「見掛け気孔率」とも呼ばれる。なお、本実施形態では、閉気孔はほとんど形成されないため、この「見掛け気孔率」を「気孔率」として取り扱うことができる。 The amount of the ceramic particles 1 in the suspension is preferably in the range of 1 to 50 vol%, more preferably 1 to 30 vol%. If the blending amount of the ceramic particles 1 is less than 1 vol%, for example, the shape may not be maintained in the drying process, and it becomes difficult to produce the porous ceramic 11 having a desired strength. Moreover, when the compounding quantity of the ceramic particle 1 exceeds 50 vol%, the porous ceramic 11 to be obtained has a low porosity and may not sufficiently exhibit the characteristics desired as a porous body. Here, the “porosity” refers to a value obtained by the Archimedes method based on the method defined in JIS R1634: 2008. In such a measurement, closed pores are not taken into account and are also referred to as “apparent porosity”. In the present embodiment, since closed pores are hardly formed, this “apparent porosity” can be handled as “porosity”.
また、水溶性高分子２としては、ゲル化工程から乾燥工程までセラミックス粒子１の分散を安定的に保持することができるものであればその種類に制限はない。具体的には、例えば、Ｎ−アルキルアミド系高分子、Ｎ−イソプロピルアクリルアミド系高分子、スルホメチル化アクリルアミド系高分子、Ｎ−ジメチルアミノプロピルメタクリルアミド系高分子、ポリアルキルアクリルアミド系高分子、アルギン酸、アルギン酸ナトリウム、アルギン酸アンモニウム、ポリエチレンイミン、カルボキシメチルセルロース、ヒドロキシメチルセルロース、メチルセルロース、ヒドロキシエチルセルロース、ヒドロキシプロピルメチルセルロース、ヒドロキシエチルメチルセルロース、ポリアクリル酸ナトリウム、ポリエチレングリコール、ポリエチレンオキシド、ポリビニルアルコール、ポリビニルピロリドン、カルボキシビニルポリマー、デンプン、ゼラチン、寒天、ペクチン、グルコマンナン、キサンタンガム、ローカストビーンガム、カラギーナンガム、グァーガム、およびジェランガムのうち１種または２種以上を水溶性高分子２として適用できるが、これらに限定されない。 The water-soluble polymer 2 is not limited in its type as long as it can stably maintain the dispersion of the ceramic particles 1 from the gelation step to the drying step. Specifically, for example, N-alkylamide polymer, N-isopropylacrylamide polymer, sulfomethylated acrylamide polymer, N-dimethylaminopropyl methacrylamide polymer, polyalkylacrylamide polymer, alginic acid, Sodium alginate, ammonium alginate, polyethyleneimine, carboxymethylcellulose, hydroxymethylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, sodium polyacrylate, polyethylene glycol, polyethylene oxide, polyvinyl alcohol, polyvinylpyrrolidone, carboxyvinyl polymer, starch , Gelatin, agar, pectin, glucomannan, xantha Gum, locust bean gum, carrageenan gum, guar gum, and one or more of the gellan gum can be applied as a water-soluble polymer 2 is not limited thereto.
また、懸濁体中の水溶性高分子２の配合量は、ゲル化工程から乾燥工程までセラミックス粒子１の分散を安定的に保持することができる程度であれば制限はない。具体的には、例えば、１００質量％の水３に対して、水溶性高分子２を０．５〜１０質量％の割合で配合することが好ましい。水溶性高分子２の配合量が０．５質量％未満だと、例えば乾燥工程において形状を維持することができず、所望の強度を有する多孔質セラミックス１１を製作することが困難となる場合がある。一方、水溶性高分子２の配合量が１０質量％を超えると、水３への溶解が不十分となり、懸濁体としての均一な攪拌・混合が困難となる場合がある。 The amount of the water-soluble polymer 2 in the suspension is not limited as long as the dispersion of the ceramic particles 1 can be stably maintained from the gelation step to the drying step. Specifically, for example, the water-soluble polymer 2 is preferably blended at a ratio of 0.5 to 10% by mass with respect to 100% by mass of water 3. If the blending amount of the water-soluble polymer 2 is less than 0.5% by mass, for example, the shape cannot be maintained in the drying step, and it may be difficult to produce the porous ceramic 11 having a desired strength. is there. On the other hand, if the blending amount of the water-soluble polymer 2 exceeds 10% by mass, dissolution in water 3 may be insufficient, and uniform stirring and mixing as a suspension may be difficult.
なお、懸濁体中へのセラミックス粒子１の均一な分散を容易にするために、セラミックス粒子１の種類に応じた分散剤を適用しても良い。また、セラミックス粒子１を適切に焼成させるために、懸濁体にセラミックス粒子１の種類に応じた焼成助剤を配合しても良い。また、懸濁体を適切にゲル化させるために、必要であれば水溶性高分子２の種類に応じたｐＨ調整剤や開始剤、架橋剤、増粘剤などの各種添加剤を添加しても良い。 In order to facilitate uniform dispersion of the ceramic particles 1 in the suspension, a dispersant corresponding to the type of the ceramic particles 1 may be applied. In order to appropriately fire the ceramic particles 1, a firing aid corresponding to the type of the ceramic particles 1 may be blended in the suspension. In addition, in order to appropriately gel the suspension, various additives such as a pH adjuster, an initiator, a crosslinking agent, and a thickener according to the type of the water-soluble polymer 2 are added if necessary. Also good.
また、凍結工程におけるゲル化体４の凍結温度は、ゲル化体４中の水３が凍結して氷５を生成することが可能な程度であれば制限はない。なお、水溶性高分子２の種類によっては、水溶性高分子２と水３との相互作用により−１０℃以上ではゲル化体４が凍結しない場合があるため、−１０℃以下の凍結温度が好ましい。 The freezing temperature of the gelled body 4 in the freezing step is not limited as long as the water 3 in the gelled body 4 can be frozen to produce the ice 5. Depending on the type of the water-soluble polymer 2, the gelled body 4 may not freeze at −10 ° C. or higher due to the interaction between the water-soluble polymer 2 and water 3. preferable.
また、乾燥工程において、凍結体６の内外の乾燥速度の差を抑制しながら、徐々に氷５を気孔１０に置換することにより亀裂を防ぐ乾燥手法を利用することが可能である。具体的には、凍結体６を凍結乾燥、あるいは水溶性有機溶剤や水溶性有機溶剤水溶液中への浸漬と風乾により、氷５を気孔１０に置換することができる。 Further, in the drying process, it is possible to use a drying technique for preventing cracks by gradually replacing the ice 5 with the pores 10 while suppressing the difference in the drying speed inside and outside the frozen body 6. Specifically, the ice 5 can be replaced with the pores 10 by freeze-drying the frozen body 6 or immersing in a water-soluble organic solvent or a water-soluble organic solvent aqueous solution and air-drying.
例えば、凍結体６を水溶性有機溶剤や水溶性有機溶剤水溶液中に浸漬すると、凍結体６中の氷５は融解し、水溶性有機溶剤と混合される。かかる操作を１回または複数回実行することにより、まず、凍結体６中の氷５であった部分は水溶性有機溶剤に置換される。その後、凍結体６内部が水溶性有機溶剤で置換された凍結体６を、大気中または減圧条件下において乾燥させると、凍結工程において氷５であった部分が気孔１０に置換される。 For example, when the frozen body 6 is immersed in a water-soluble organic solvent or a water-soluble organic solvent aqueous solution, the ice 5 in the frozen body 6 is melted and mixed with the water-soluble organic solvent. By performing this operation once or a plurality of times, first, the portion that was ice 5 in the frozen body 6 is replaced with a water-soluble organic solvent. Thereafter, when the frozen body 6 in which the inside of the frozen body 6 has been replaced with a water-soluble organic solvent is dried in the air or under reduced pressure conditions, the portion that was ice 5 in the freezing step is replaced with pores 10.
水溶性有機溶剤を利用した乾燥工程において、水溶性有機溶剤としては、水溶性高分子２を浸食せず、かつ水３よりも揮発性が高いものが適用される。具体的には、メタノール、エタノール、イソプロピルアルコール、アセトン、酢酸エチルなどが挙げられるが、これらに限定されない。これらの水溶性有機溶剤を単独で、あるいは複数種類併用した乾燥を１回または複数回実行することにより、凍結体６内で氷５であった部分に、気孔１０が形成される。 In the drying process using the water-soluble organic solvent, a water-soluble organic solvent that does not erode the water-soluble polymer 2 and has higher volatility than the water 3 is applied. Specific examples include, but are not limited to, methanol, ethanol, isopropyl alcohol, acetone, and ethyl acetate. By performing drying using these water-soluble organic solvents alone or in combination of a plurality of types once or a plurality of times, pores 10 are formed in the portions that were ice 5 in the frozen body 6.
また、脱脂工程において、例えば３００℃〜９００℃の脱脂温度が適用される。ここで、例えば、炭化珪素、窒化珪素などの非酸化物セラミックスを脱脂する場合には、アルゴンや窒素などの不活性ガス雰囲気下で脱脂をすることが好ましい。これに対し、例えば、アルミナ、ジルコニア、アパタイトなどの酸化物セラミックスを原料とする場合には、大気雰囲気下で脱脂をすることが好ましい。 In the degreasing step, for example, a degreasing temperature of 300 ° C. to 900 ° C. is applied. Here, for example, when degreasing non-oxide ceramics such as silicon carbide and silicon nitride, it is preferable to degrease in an inert gas atmosphere such as argon or nitrogen. On the other hand, for example, when using oxide ceramics such as alumina, zirconia, and apatite as a raw material, it is preferable to degrease in an air atmosphere.
そして、焼成工程では、使用するセラミックス粒子１の種類や配合量、目標とする強度等に応じて、焼成温度、焼成時間および焼成雰囲気が適宜調整されることにより、気孔径のばらつきが少ない多孔質セラミックス１１が作製される。 And in a baking process, according to the kind and compounding quantity of the ceramic particle 1 to be used, target intensity | strength, etc., by adjusting suitably a baking temperature, baking time, and baking atmosphere, it is a porous with few dispersion | variation in a pore diameter. The ceramic 11 is produced.
このようにして得られる多孔質セラミックス１１の構成について、図４を用いて説明する。図４は、実施形態に係る多孔質セラミックス１１の模式図である。 The configuration of the porous ceramic 11 thus obtained will be described with reference to FIG. FIG. 4 is a schematic diagram of the porous ceramic 11 according to the embodiment.
図４に示すように、実施形態に係る多孔質セラミックス１１は、気孔１０の平均アスペクト比が２．０以上、好ましくは３．５以上となるように形成される。このような平均アスペクト比を有する気孔１０は、例えば、互いに向かい合う一方の面ｆ１から他方の面ｆ２に向かって一方向に配向するように形成される。 As shown in FIG. 4, the porous ceramic 11 according to the embodiment is formed so that the average aspect ratio of the pores 10 is 2.0 or more, preferably 3.5 or more. The pores 10 having such an average aspect ratio are formed, for example, so as to be oriented in one direction from one surface f 1 facing each other toward the other surface f 2 .
また、実施形態に係る多孔質セラミックス１１は、気孔径のばらつきが１３０％以下であり、好ましくは８５％以下である。気孔径のばらつきが１３０％を超えると、例えば、粗大な気孔を含むことで局所的に機械的強度が低い箇所が生じ、取扱い上の不具合が生じることがある。また、気孔径がばらつくことで濾過特性がばらつくため、例えばフィルタ用途での使用において不具合が生じる懸念がある。なお、気孔径のばらつきは、後述する実施例に記載する方法により測定することができる。 Further, the porous ceramic 11 according to the embodiment has a pore size variation of 130% or less, preferably 85% or less. When the variation in pore diameter exceeds 130%, for example, the presence of coarse pores may cause a location where the mechanical strength is locally low, resulting in handling problems. Moreover, since the filtration characteristics vary due to variations in the pore diameter, there is a concern that problems may occur in use in filter applications, for example. In addition, the variation in pore diameter can be measured by the method described in Examples described later.
また、実施形態に係る多孔質セラミックス１１は、平均気孔径が１μｍ〜５００μｍであることが実用上好ましく、より好ましくは１２μｍ〜１０２μｍである。なお、平均気孔径は、後述する実施例に記載する方法により測定することができる。 Moreover, it is practically preferable that the porous ceramics 11 which concern on embodiment are 1 micrometer-500 micrometers in average pore diameter, More preferably, they are 12 micrometers-102 micrometers. In addition, an average pore diameter can be measured by the method described in the Example mentioned later.
また、実施形態に係る多孔質セラミックス１１の気孔率は、５０％〜９９％の範囲が好ましく、より好ましくは７０％〜９９％である。多孔質セラミックス１１の気孔率が５０％未満だと、実施形態に係る多孔質セラミックス１１の製造方法を用いる必要性が低減する。また、多孔質セラミックス１１の気孔率が９９％を超えると、例えば乾燥工程において形状を維持することができない場合があり、また、所望の強度を有する多孔質セラミックス１１を製作することが困難となる。 In addition, the porosity of the porous ceramic 11 according to the embodiment is preferably in the range of 50% to 99%, more preferably 70% to 99%. When the porosity of the porous ceramic 11 is less than 50%, the necessity of using the method for manufacturing the porous ceramic 11 according to the embodiment is reduced. Further, if the porosity of the porous ceramic 11 exceeds 99%, for example, the shape may not be maintained in the drying process, and it becomes difficult to produce the porous ceramic 11 having a desired strength. .
次に、実施形態に係る多孔質セラミックス１１を製造する方法について、図７を用いて詳細に説明する。図７は、実施形態に係る多孔質セラミックス１１を製造する処理手順を示すフローチャートである。 Next, a method for producing the porous ceramic 11 according to the embodiment will be described in detail with reference to FIG. FIG. 7 is a flowchart showing a processing procedure for manufacturing the porous ceramic 11 according to the embodiment.
図７に示すように、まず、セラミックス粒子１と、水溶性高分子２と、水３とを混合して懸濁体を調製する（ステップＳ１０１）。焼成助剤やｐＨ調整剤、開始剤、架橋剤などの各種添加剤は、このタイミングで添加すると良い。なお、水溶性高分子２は、セラミックス粒子１と混合する前に予め水３と混合して水溶液としたものを使用しても良く、また、水溶性高分子２とセラミックス粒子１とを予め混合したものを攪拌中の水３に添加しても良い。そして、分散剤を使用する場合には、セラミックス粒子１と予め混合しておくことが好ましい。 As shown in FIG. 7, first, ceramic particles 1, water-soluble polymer 2, and water 3 are mixed to prepare a suspension (step S101). Various additives such as a baking aid, a pH adjuster, an initiator, and a crosslinking agent may be added at this timing. The water-soluble polymer 2 may be used as an aqueous solution by mixing with water 3 in advance before mixing with the ceramic particles 1, or the water-soluble polymer 2 and ceramic particles 1 may be mixed in advance. The product may be added to the water 3 being stirred. And when using a dispersing agent, it is preferable to mix with the ceramic particle 1 previously.
続いて、ステップＳ１０１において調製した懸濁体をゲル化させてゲル化体４を形成する（ステップＳ１０２）。懸濁体のゲル化を促進させるために、必要であれば懸濁体を加熱しても良い。 Subsequently, the suspension prepared in step S101 is gelled to form a gelled body 4 (step S102). In order to promote gelation of the suspension, the suspension may be heated if necessary.
次に、実施形態に係る冷却装置１２を用いてゲル化体４を凍結させて氷５の結晶が一方向に成長した凍結体６を生成する（ステップＳ１０３）。続いて、凍結体６を乾燥させて凍結体６に成長した氷５を除去し、気孔１０を生成する（ステップＳ１０４）。 Next, the gelled body 4 is frozen using the cooling device 12 according to the embodiment, and the frozen body 6 in which the crystals of the ice 5 grow in one direction is generated (step S103). Subsequently, the frozen body 6 is dried and the ice 5 grown on the frozen body 6 is removed to generate pores 10 (step S104).
さらに、氷５が除去されて気孔１０が生成された凍結体６から水溶性高分子２等の有機成分を除去する脱脂を行い（ステップＳ１０５）、引き続いて焼成を行う（Ｓ１０６）。以上の各工程により、実施形態に係る一連の多孔質セラミックス１１の製造が終了する。 Further, degreasing is performed to remove organic components such as the water-soluble polymer 2 from the frozen body 6 in which the ice 5 is removed and the pores 10 are generated (step S105), and then baking is performed (S106). Through the above steps, the production of a series of porous ceramics 11 according to the embodiment is completed.
上述してきたように、実施形態に係る多孔質セラミックスの製造方法は、ゲル化工程と、凍結工程と、焼成工程とを含む。ゲル化工程は、セラミックス粒子と、水溶性高分子と、水とを含む懸濁体を、ステンレス鋼、鉄、銅またはアルミニウム製の型に入れてゲル化させたゲル化体を生成する工程である。凍結工程は、ゲル化体を凍結させて凍結体を生成する工程である。乾燥工程は、凍結体に成長した氷を除去して気孔を生成する工程である。焼成工程は、氷が除去された凍結体を焼成する工程である。凍結工程は、対面する一方の側から他方の側に表層部分が流動する冷媒にゲル化体の入った型の底板を接触させてゲル化体の下面側から凍結させる工程である。 As described above, the method for producing a porous ceramic according to the embodiment includes a gelling step, a freezing step, and a firing step. The gelling step is a step of generating a gelled body in which a suspension containing ceramic particles, a water-soluble polymer, and water is placed in a mold made of stainless steel, iron, copper, or aluminum and gelled. is there. The freezing step is a step of generating a frozen body by freezing the gelled body. The drying step is a step of generating pores by removing ice grown on the frozen body. The firing step is a step of firing the frozen body from which the ice has been removed. The freezing step is a step of freezing from the lower surface side of the gelled body by bringing the bottom plate of the type containing the gelled body into contact with the refrigerant whose surface layer portion flows from one side to the other side.
したがって、実施形態に係る多孔質セラミックスの製造方法によれば、気孔径のばらつきが少ない多孔質セラミックスを作製することができる。 Therefore, according to the method for producing a porous ceramic according to the embodiment, it is possible to produce a porous ceramic with little variation in pore diameter.
ところで、実施形態に係る多孔質セラミックスが気孔径のばらつきが少ないことによる利点としては、例えば、以下のことが挙げられる。 By the way, as an advantage by the porous ceramics which concern on embodiment having few dispersion | variation in a pore diameter, the following is mentioned, for example.
まず、実施形態に係る多孔質セラミックスは、気孔径のばらつきが少なく、機械的強度にばらつきが生じ難いので、局所的に機械的強度が劣ることによる使用上の不具合を低減することができる。また、実施形態に係る多孔質セラミックスを例えばフィルタとして利用すると、気孔径のばらつきが少ないことで濾過特性が安定する。かかる用途の場合には、一方向に配向した気孔を有することが好ましい。 First, since the porous ceramics according to the embodiment have little variation in pore diameter and hardly cause variation in mechanical strength, it is possible to reduce problems in use due to locally inferior mechanical strength. Further, when the porous ceramic according to the embodiment is used as a filter, for example, the filtration characteristics are stabilized due to the small variation in pore diameter. For such applications, it is preferable to have pores oriented in one direction.
さらに、実施形態に係る多孔質セラミックスを、例えば積層セラミックスコンデンサなどの電子部品を載せて窯炉内で焼成するための焼成治具（例えば、セッター、さや（匣鉢）またはラックなど）として利用すると、電子部品焼成時の脱脂効果がほぼ均等になり、窯炉内の配置によらず焼成した電子部品の諸物性が安定する。かかる用途の場合、上面から下面に向かって一方向に配向するように形成された気孔を有する多孔質セラミックスを適用することが好ましい。 Furthermore, when the porous ceramic according to the embodiment is used as a firing jig (for example, a setter, a sheath (a mortar) or a rack) for placing an electronic component such as a multilayer ceramic capacitor and firing it in a kiln. In addition, the degreasing effect at the time of firing the electronic parts becomes almost uniform, and the physical properties of the fired electronic parts are stabilized regardless of the arrangement in the kiln. For such applications, it is preferable to apply porous ceramics having pores formed so as to be oriented in one direction from the upper surface to the lower surface.
なお、上述した実施形態では、冷却装置１２は型２３をゲル化体支持部１４ａ，１４ｂに直接配置する構成として説明したが、かかる構成に限定されない。例えば、網状の、または複数の開口を有するカゴまたは棚の上に型２３を静置し、このカゴまたは棚をゲル化体支持部１４ａ，１４ｂに支持されるように配置する構成としても良い。 In the above-described embodiment, the cooling device 12 has been described as a configuration in which the mold 23 is directly disposed on the gelled body support portions 14a and 14b. However, the configuration is not limited thereto. For example, the mold 23 may be placed on a net or a basket or shelf having a plurality of openings, and the basket or shelf may be arranged to be supported by the gelled body support portions 14a and 14b.
また、上述した実施形態では、冷却装置１２における冷媒１７は仕切板２５の上側を冷媒調整部１５から冷却槽１３に送られ、仕切板２５の終端２５ａよりも奥で鉛直下向きに潜り込むように流動し、次いで仕切板２５の下側を冷却槽１３から冷媒調整部１５に送られる構成として説明したが、かかる構成に限定されない。すなわち、冷媒１７が仕切板２５の下側を冷媒調整部１５から冷却槽１３に送られ、仕切板２５の終端２５ａよりも奥で鉛直上向きに湧き出るように流動し、次いで仕切板２５の上側を冷却槽１３から冷媒調整部１５に送られる構成としても良い。 Further, in the above-described embodiment, the refrigerant 17 in the cooling device 12 is sent from the refrigerant adjustment unit 15 to the cooling tank 13 on the upper side of the partition plate 25, and flows so as to sink vertically downward from the end 25 a of the partition plate 25. Then, although the lower side of the partition plate 25 has been described as a configuration that is sent from the cooling tank 13 to the refrigerant adjustment unit 15, the configuration is not limited thereto. That is, the refrigerant 17 is sent from the refrigerant adjusting unit 15 to the cooling tank 13 on the lower side of the partition plate 25 and flows so as to spring up vertically behind the end 25a of the partition plate 25, and then on the upper side of the partition plate 25. It is good also as a structure sent to the refrigerant | coolant adjustment part 15 from the cooling tank 13. FIG.
また、上述した実施形態では、脱脂工程（ステップＳ１０５）は必須の工程として説明したが、水溶性高分子２の種類および配合量によっては省略しても良い。かかる場合、水溶性高分子２は焼成工程（ステップＳ１０６）において分解、除去される。 Moreover, although the degreasing process (step S105) was demonstrated as an essential process in embodiment mentioned above, you may abbreviate | omit depending on the kind and compounding quantity of the water-soluble polymer 2. FIG. In such a case, the water-soluble polymer 2 is decomposed and removed in the firing step (step S106).
（実施例１）
平均粒径０．５μｍのアルミナ粒子（セラミックス粒子１に対応）１０ｖｏｌ％と、水９０．０ｖｏｌ％とを混合した。これにゼラチン（水溶性高分子２に対応）３．０質量％（水３に対して）を添加して調製した懸濁体を銅製の型２３に入れ、５℃の冷蔵庫内に静置し、ゲル化体４を得た。
Example 1
10 vol% of alumina particles (corresponding to ceramic particles 1) having an average particle diameter of 0.5 μm and 90.0 vol% of water were mixed. A suspension prepared by adding 3.0% by mass of gelatin (corresponding to water-soluble polymer 2) (with respect to water 3) was placed in a copper mold 23 and left in a refrigerator at 5 ° C. Thus, a gelled body 4 was obtained.
次に、ゲル化体４の入った型２３を、冷媒１７として−３５℃のエタノールを適用した冷却装置１２で冷却し、凍結体６を生成させた。続いて凍結体６を型２３から取り出し、凍結乾燥装置で２４時間乾燥した。さらに、大気雰囲気下の電気炉にて６００℃で２時間脱脂した後、１６００℃で２時間焼成することにより、鉛直方向の厚さｃ＝９ｍｍの多孔質セラミックス１１が得られ、さらに水平方向の幅を均等に揃える加工を施す事により、ａ×ｂ×ｃ＝１００ｍｍ×１００ｍｍ×９ｍｍとした（図６参照）。なお、加工を施す前の多孔質セラミックス１１の水平方向の幅ａ×ｂは、（１０４〜１０６）ｍｍ×（１０４〜１０６）ｍｍ程度となる。得られた多孔質セラミックス１１の気孔率、気孔１０の平均アスペクト比、平均気孔径、および気孔径のばらつきを、型２３の厚みおよび材質と共に表１に示す。また、本実施例で作製した多孔質セラミックス１１の部分縦断面図を図５Ａに示す。 Next, the mold 23 containing the gelled body 4 was cooled by the cooling device 12 to which −35 ° C. ethanol was applied as the refrigerant 17 to generate the frozen body 6. Subsequently, the frozen body 6 was taken out from the mold 23 and dried for 24 hours with a freeze-drying apparatus. Furthermore, after degreasing at 600 ° C. for 2 hours in an electric furnace in an air atmosphere, the porous ceramic 11 having a vertical thickness c = 9 mm is obtained by firing at 1600 ° C. for 2 hours. By performing a process for evenly aligning the width, a × b × c = 100 mm × 100 mm × 9 mm was obtained (see FIG. 6). The horizontal width a × b of the porous ceramics 11 before processing is about (104 to 106) mm × (104 to 106) mm. Table 1 shows the porosity of the obtained porous ceramic 11, the average aspect ratio of the pores 10, the average pore diameter, and the variation in the pore diameter, along with the thickness and material of the mold 23. Moreover, the partial longitudinal cross-sectional view of the porous ceramics 11 produced by the present Example is shown to FIG. 5A.
ここで、多孔質セラミックス１１の「気孔１０のアスペクト比」は、図５Ａに示す部分縦断面図の画像解析に基づいて算出することができる。すなわち、気孔１０の断面部を楕円体に近似し、面積、長径および短径を測定したときの長径から短径を除した値を「気孔１０のアスペクト比」という。そして、任意に選択した５０個の気孔１０のアスペクト比の平均値を、「気孔１０の平均アスペクト比」と規定する。 Here, the “aspect ratio of the pores 10” of the porous ceramic 11 can be calculated based on the image analysis of the partial longitudinal sectional view shown in FIG. 5A. That is, the cross section of the pore 10 is approximated to an ellipsoid, and a value obtained by dividing the major axis when the area, major axis, and minor axis are measured is referred to as “aspect ratio of the pore 10”. Then, an average value of the aspect ratios of 50 pores 10 arbitrarily selected is defined as “average aspect ratio of the pores 10”.
また、多孔質セラミックス１１の「平均気孔径」および「気孔径のばらつき」は、次のようにして算出した。まず、作製された多孔質セラミックス１１を、図６に示すように幅ａ１×ｂ１＝１５ｍｍ×１５ｍｍ、厚さｃ＝９ｍｍの試料片として中央（α）と端部（β、γ、δ、ε）の計５ヶ所からそれぞれ切り出した。次に、この５つの試料片についてそれぞれ平均気孔径を算出した。ここで、各試料片の「平均気孔径」とは、接触角１４０度で水銀圧入法を用いて各試料片についてそれぞれ測定し、気孔１０を円柱近似した際の気孔分布に基づいて得られたメジアン径（ｄ５０）をいう。 The “average pore size” and “pore size variation” of the porous ceramics 11 were calculated as follows. First, as shown in FIG. 6, the produced porous ceramic 11 is formed as a sample piece having a width a 1 × b 1 = 15 mm × 15 mm and a thickness c = 9 mm as a center (α) and an end (β, γ, δ). , Ε), respectively. Next, the average pore diameter was calculated for each of the five sample pieces. Here, the “average pore diameter” of each sample piece was obtained by measuring each sample piece using a mercury intrusion method at a contact angle of 140 degrees and based on the pore distribution when the pore 10 was approximated to a cylinder. This is the median diameter (d50).
そして、各平均気孔径のうち、最大値と最小値との差を求め、この値（（最大値）−（最小値））を各平均気孔径の平均値で除した値の百分率を「気孔径のばらつき」（％）とした。また、試料片ごとに得られた平均気孔径の平均値を、多孔質セラミックス１１の「平均気孔径」と規定する。 Then, the difference between the maximum value and the minimum value among the average pore diameters is obtained, and the percentage of the value obtained by dividing this value ((maximum value) − (minimum value)) by the average value of each average pore diameter is expressed as “cell Variation in pore diameter ”(%). Further, the average value of the average pore diameter obtained for each sample piece is defined as the “average pore diameter” of the porous ceramic 11.
（実施例２）
型２３の厚みを変更したことを除き、実施例１と同様にして多孔質セラミックス１１を得た。得られた多孔質セラミックス１１の気孔率、気孔１０の平均アスペクト比、平均気孔径、および気孔径のばらつきを、型２３の厚みおよび材質と共に表１に示す。
(Example 2)
A porous ceramic 11 was obtained in the same manner as in Example 1 except that the thickness of the mold 23 was changed. Table 1 shows the porosity of the obtained porous ceramic 11, the average aspect ratio of the pores 10, the average pore diameter, and the variation in the pore diameter, along with the thickness and material of the mold 23.
（実施例３）
型２３の材質をアルミニウム（Ａｌ）に変更したことを除き、実施例２と同様にして多孔質セラミックス１１を得た。得られた多孔質セラミックス１１の気孔率、気孔１０の平均アスペクト比、平均気孔径、および気孔径のばらつきを、型２３の厚みおよび材質と共に表１に示す。
(Example 3)
A porous ceramic 11 was obtained in the same manner as in Example 2 except that the material of the mold 23 was changed to aluminum (Al). Table 1 shows the porosity of the obtained porous ceramic 11, the average aspect ratio of the pores 10, the average pore diameter, and the variation in the pore diameter, along with the thickness and material of the mold 23.
（実施例４）
型２３の材質をステンレス鋼（ＳＵＳ）に変更したことを除き、実施例２と同様にして多孔質セラミックス１１を得た。得られた多孔質セラミックス１１の気孔率、気孔１０の平均アスペクト比、平均気孔径、および気孔径のばらつきを、型２３の厚みおよび材質と共に表１に示す。
Example 4
A porous ceramic 11 was obtained in the same manner as in Example 2 except that the material of the mold 23 was changed to stainless steel (SUS). Table 1 shows the porosity of the obtained porous ceramic 11, the average aspect ratio of the pores 10, the average pore diameter, and the variation in the pore diameter, along with the thickness and material of the mold 23.
（実施例５）
型２３の材質および厚みを変更したことを除き、実施例１と同様にして多孔質セラミックス１１を得た。得られた多孔質セラミックス１１の気孔率、気孔１０の平均アスペクト比、平均気孔径、および気孔径のばらつきを、型２３の厚みおよび材質と共に表１に示す。
(Example 5)
A porous ceramic 11 was obtained in the same manner as in Example 1 except that the material and thickness of the mold 23 were changed. Table 1 shows the porosity of the obtained porous ceramic 11, the average aspect ratio of the pores 10, the average pore diameter, and the variation in the pore diameter, along with the thickness and material of the mold 23.
（実施例６）
エタノールの温度を−２０℃としたことを除き、実施例４と同様にして多孔質セラミックス１１を得た。得られた多孔質セラミックス１１の気孔率、気孔１０の平均アスペクト比、平均気孔径、および気孔径のばらつきを、型２３の厚みおよび材質と共に表１に示す。
(Example 6)
A porous ceramic 11 was obtained in the same manner as in Example 4 except that the temperature of ethanol was −20 ° C. Table 1 shows the porosity of the obtained porous ceramic 11, the average aspect ratio of the pores 10, the average pore diameter, and the variation in the pore diameter, along with the thickness and material of the mold 23.
（実施例７）
エタノールの温度を−１０℃としたことを除き、実施例１と同様にして多孔質セラミックス１１を得た。得られた多孔質セラミックス１１の気孔率、気孔１０の平均アスペクト比、平均気孔径、および気孔径のばらつきを、型２３の厚みおよび材質と共に表１に示す。
(Example 7)
A porous ceramic 11 was obtained in the same manner as in Example 1 except that the temperature of ethanol was −10 ° C. Table 1 shows the porosity of the obtained porous ceramic 11, the average aspect ratio of the pores 10, the average pore diameter, and the variation in the pore diameter, along with the thickness and material of the mold 23.
（実施例８）
セラミックス粒子１として平均粒径０．７μｍのイットリア完全安定化ジルコニア粒子を使用したことを除き、実施例１と同様にして多孔質セラミックス１１を得た。得られた多孔質セラミックス１１の気孔率、気孔１０の平均アスペクト比、平均気孔径、および気孔径のばらつきを、型２３の厚みおよび材質と共に表１に示す。また、本実施例で作製した多孔質セラミックス１１の部分縦断面図を図５Ｂに示す。
(Example 8)
A porous ceramic 11 was obtained in the same manner as in Example 1 except that yttria fully stabilized zirconia particles having an average particle diameter of 0.7 μm were used as the ceramic particles 1. Table 1 shows the porosity of the obtained porous ceramic 11, the average aspect ratio of the pores 10, the average pore diameter, and the variation in the pore diameter, along with the thickness and material of the mold 23. Moreover, the partial longitudinal cross-sectional view of the porous ceramics 11 produced by the present Example is shown to FIG. 5B.
（比較例１）
冷却装置１２を冷却装置１２ａに変更したことを除き、実施例１と同様にして多孔質セラミックス１１を得た。得られた多孔質セラミックス１１の気孔率、気孔１０の平均アスペクト比、平均気孔径、および気孔径のばらつきを、型２３の厚みおよび材質と共に表１に示す。
(Comparative Example 1)
A porous ceramic 11 was obtained in the same manner as in Example 1 except that the cooling device 12 was changed to the cooling device 12a. Table 1 shows the porosity of the obtained porous ceramic 11, the average aspect ratio of the pores 10, the average pore diameter, and the variation in the pore diameter, along with the thickness and material of the mold 23.
実施例および比較例において使用した冷媒１７の温度、型２３の厚みおよび材質、ならびに作製した多孔質セラミックス１１について、表１にまとめて示す。 Table 1 summarizes the temperature of the refrigerant 17, the thickness and material of the mold 23, and the produced porous ceramic 11 used in the examples and comparative examples.
表１に示されるように、実施例１〜８のように作製された多孔質セラミックス１１はいずれも、気孔１０の平均アスペクト比が３．５以上であり、互いに向かい合う一方の面から他方の面に向かって一方向に配向するように気孔１０が形成されている（図５Ａ、５Ｂ参照）。また、実施例１〜８のように作製された多孔質セラミックス１１ではいずれも、適用する冷却装置１２が比較例１とは相違することに起因して、気孔径のばらつきが８６％以下と少ない気孔１０が形成されたことがわかる。 As shown in Table 1, all of the porous ceramics 11 produced as in Examples 1 to 8 had an average aspect ratio of the pores of 3.5 or more, and from one surface to the other surface facing each other. The pores 10 are formed so as to be oriented in one direction toward (see FIGS. 5A and 5B). Moreover, in any of the porous ceramics 11 produced as in Examples 1 to 8, the variation in pore diameter is as small as 86% or less because the applied cooling device 12 is different from Comparative Example 1. It can be seen that the pores 10 have been formed.
また、実施例１および２を比較すると、型２３の厚みが大きい方が気孔径のばらつきが小さくなることがわかる。この理由は、型２３の厚みが大きいと、冷媒１７の温度に局所的に高低差があった場合であっても、型２３の底板２１がこの冷媒の「温度ムラ」を緩衝し、底板２１の内面２１ａ側の温度を均質化させてゲル化体４側に伝えられるためであると考えられる。 Further, comparing Examples 1 and 2, it can be seen that the larger the thickness of the mold 23, the smaller the variation in pore diameter. The reason for this is that if the thickness of the mold 23 is large, the bottom plate 21 of the mold 23 buffers the “temperature unevenness” of the refrigerant, even if there is a local height difference in the temperature of the refrigerant 17. It is considered that this is because the temperature on the inner surface 21a side is homogenized and transmitted to the gelled body 4 side.
また、実施例２〜４を比較すると、型２３としてステンレス鋼を適用した場合に気孔径のばらつきが最も小さくなることがわかる。この理由としては、例えば、ステンレス鋼の方が、他の物質（銅およびアルミニウム）よりも単位体積当たりの比熱が大きいことに起因して冷媒１７のごく局所的な温度差をも型２３に伝達させにくいためであると解釈することができる。 Moreover, when Examples 2-4 are compared, when stainless steel is applied as the mold | type 23, it turns out that the dispersion | variation in a pore diameter becomes the smallest. The reason for this is that, for example, stainless steel has a higher specific heat per unit volume than other substances (copper and aluminum), so that a very local temperature difference of the refrigerant 17 is also transmitted to the mold 23. It can be interpreted that it is difficult to prevent.
なお、上述において、ゲル化体４およびこのゲル化体４から凍結体６を経て作製される多孔質セラミックス１１の形状は直方体、すなわち四角柱として説明したが、これに限定されるものではない。ゲル化体４および凍結体６を生成するための型２３の、特に周壁２２の形状を変更することにより、多孔質セラミックス１１の形状を例えば三角柱、五角柱などの多角柱、円柱または楕円柱など自由に変更させることができる。 In the above description, the shape of the gelled body 4 and the porous ceramics 11 produced from the gelled body 4 through the frozen body 6 has been described as a rectangular parallelepiped, that is, a quadrangular prism, but is not limited thereto. By changing the shape of the mold 23 for generating the gelled body 4 and the frozen body 6, especially the shape of the peripheral wall 22, the shape of the porous ceramic 11 is changed to a polygonal column such as a triangular prism or a pentagonal column, a cylinder or an elliptical column, etc. It can be changed freely.
また、作製された多孔質セラミックス１１の形状に応じて、セラミックス粒子１の「平均気孔径」および「気孔径のばらつき」を測定するために試料片を切り出す位置および形状ならびに切り出す試験片の個数を自由に変更させることができる。 Further, in order to measure the “average pore diameter” and “pore size variation” of the ceramic particles 1 in accordance with the shape of the produced porous ceramics 11, the position and shape of the sample piece and the number of test pieces to be cut out are determined. It can be changed freely.
さらなる効果や変形例は、当業者によって容易に導き出すことができる。このため、本発明のより広範な態様は、以上のように表しかつ記述した特定の詳細および代表的な実施形態に限定されるものではない。したがって、添付の特許請求の範囲およびその均等物によって定義される総括的な発明の概念の精神または範囲から逸脱することなく、様々な変更が可能である。 Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
１ セラミックス粒子
２ 水溶性高分子
３ 水
４，４ａ ゲル化体
５ 氷
６ 凍結体
７ 下面
８ 上面
９ セラミックス骨格
１０ 気孔
１１ 多孔質セラミックス
１２，１２ａ 冷却装置
１３，１３ａ 冷却槽
１４ａ，１４ｂ ゲル化体支持部
１５，１５ａ 冷媒調整部
１６ 冷凍機
１７，１７ａ 冷媒
１８ モータ
１９ シャフト
２０，２０ａ プロペラ
２１ 底板
２１ａ 内面
２１ｂ 外面
２２ 周壁
２２ａ 内周面
２３，２３ａ 型
２４ 制御部
２５ 仕切板
２５ａ 終端
２６ 冷媒供給口
２７ 冷媒排出口
DESCRIPTION OF SYMBOLS 1 Ceramic particle 2 Water-soluble polymer 3 Water 4, 4a Gelled body 5 Ice 6 Frozen body 7 Lower surface 8 Upper surface 9 Ceramic skeleton 10 Pore 11 Porous ceramics 12, 12a Cooling device 13, 13a Cooling tank 14a, 14b Gelled body Support parts 15, 15a Refrigerant adjustment part 16 Refrigerator 17, 17a Refrigerant 18 Motor 19 Shaft 20, 20a Propeller 21 Bottom plate 21a Inner surface 21b Outer surface 22 Peripheral wall 22a Inner peripheral surface 23, 23a Type 24 Control unit 25 Partition plate 25a Termination 26 Refrigerant supply Port 27 Refrigerant outlet
Claims (7)
気孔率が５０〜９９％であり、
気孔径のばらつきが１３０％以下であり、
気孔の平均アスペクト比が２．０以上であり、
前記気孔が、互いに向かい合う一方の面から他方の面に向かって一方向に配向するように形成され、
水平方向の寸法が１００００ｍｍ ２ 以上である
ことを特徴とする焼成治具用多孔質セラミックス。 The average pore diameter is 1 to 500 μm,
The porosity is 50-99%,
Ri Der variation of pore diameter less 130%,
The average aspect ratio of the pores is 2.0 or more,
The pores are formed to be oriented in one direction from one surface facing each other to the other surface;
Firing jig porous ceramics in which the horizontal dimension, wherein the Ru der 10000 mm 2 or more.
前記ゲル化体を凍結させて凍結体を生成する凍結工程と、
前記凍結体に成長した氷を除去して気孔を生成する乾燥工程と、
前記氷が除去された前記凍結体を焼成する焼成工程と
を含み、
前記凍結工程は、対面する一方の側から他方の側に表層部分が流動する冷媒に前記ゲル化体の入った前記型の底板を接触させて前記ゲル化体の下面側から凍結させる工程であることを特徴とする焼成治具用多孔質セラミックスの製造方法。 A gelling step for producing a gelled body obtained by putting a suspension containing ceramic particles, a water-soluble polymer, and water into a mold made of stainless steel, iron, copper or aluminum ;
A freezing step of freezing the gelled body to produce a frozen body;
A drying step of removing the ice grown on the frozen body to generate pores;
A baking step of baking the frozen body from which the ice has been removed,
The freezing step is a step in which the bottom plate of the mold containing the gelled body is brought into contact with a refrigerant whose surface layer portion flows from one side facing to the other side to freeze from the lower surface side of the gelled body. A method for producing a porous ceramic for a firing jig .
前記冷却槽の対面する一方の側から他方の側に前記冷媒の表層部分が流動するように前記冷媒を循環させる冷媒調整層と、を備える
ことを特徴とする冷却装置。 The gelled body is made by contacting a bottom plate of a stainless steel, iron, copper or aluminum mold containing a gelled body obtained by gelling a suspension containing ceramic particles, a water-soluble polymer and water. A cooling tank for freezing from the lower surface side of the
A refrigerant adjustment layer that circulates the refrigerant so that a surface layer portion of the refrigerant flows from one side facing the cooling tank to the other side.
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| JP2013258596A JP6266972B2 (en) | 2013-12-13 | 2013-12-13 | Porous ceramic for firing jig, method for producing porous ceramic for firing jig, and cooling device |
| PCT/JP2014/080528 WO2015087665A1 (en) | 2013-12-13 | 2014-11-18 | Porous ceramic material, method for producing porous ceramic material, and cooing device |
| TW103143448A TWI646068B (en) | 2013-12-13 | 2014-12-12 | Porous ceramics, method for produce porous ceramics and cooling device |
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| JP5176198B2 (en) * | 2007-02-21 | 2013-04-03 | 独立行政法人産業技術総合研究所 | Method for producing ceramic porous body having macroporous communication holes |
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