JP5774289B2 - Manufacturing method of ceramic products - Google Patents
Manufacturing method of ceramic products Download PDFInfo
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- JP5774289B2 JP5774289B2 JP2010219869A JP2010219869A JP5774289B2 JP 5774289 B2 JP5774289 B2 JP 5774289B2 JP 2010219869 A JP2010219869 A JP 2010219869A JP 2010219869 A JP2010219869 A JP 2010219869A JP 5774289 B2 JP5774289 B2 JP 5774289B2
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- 239000000919 ceramic Substances 0.000 title claims description 86
- 238000004519 manufacturing process Methods 0.000 title description 13
- 239000002002 slurry Substances 0.000 claims description 22
- 239000002344 surface layer Substances 0.000 claims description 17
- 239000000843 powder Substances 0.000 claims description 12
- 230000003746 surface roughness Effects 0.000 claims description 11
- 239000011358 absorbing material Substances 0.000 claims description 9
- 238000000151 deposition Methods 0.000 claims description 2
- 239000007779 soft material Substances 0.000 claims 1
- 239000000047 product Substances 0.000 description 17
- 239000000463 material Substances 0.000 description 14
- 239000010410 layer Substances 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 10
- 238000001035 drying Methods 0.000 description 10
- 238000010304 firing Methods 0.000 description 9
- 238000000465 moulding Methods 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000005266 casting Methods 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 229910052602 gypsum Inorganic materials 0.000 description 5
- 239000010440 gypsum Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 239000002270 dispersing agent Substances 0.000 description 4
- 239000002904 solvent Substances 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 229920001084 poly(chloroprene) Polymers 0.000 description 3
- 229920002379 silicone rubber Polymers 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 239000006228 supernatant Substances 0.000 description 3
- 229920006311 Urethane elastomer Polymers 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 239000002250 absorbent Substances 0.000 description 2
- 230000002745 absorbent Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 239000004593 Epoxy Substances 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 241001149900 Fusconaia subrotunda Species 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 229920005549 butyl rubber Polymers 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- JEGUKCSWCFPDGT-UHFFFAOYSA-N h2o hydrate Chemical compound O.O JEGUKCSWCFPDGT-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000003002 pH adjusting agent Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- 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
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- Producing Shaped Articles From Materials (AREA)
- Moulds, Cores, Or Mandrels (AREA)
Description
本発明は、中空状のセラミックス製品の製造方法に関する。 The present invention relates to the production how the hollow ceramic product.
近年、半導体や液晶の製造装置は大型化している。これに伴い、これら装置の構造部材に用いられ、セラミックス焼結体からなるセラミックス製品も大型化している。例えば、ガイドレールは長さが１メートルを超えることもある。 In recent years, semiconductor and liquid crystal manufacturing apparatuses have become larger. Along with this, ceramic products made of ceramic sintered bodies that are used for structural members of these devices are also becoming larger. For example, the guide rail may exceed 1 meter in length.
これら装置は高精度な位置制御が必要とされ、ガイドレールなどの構造部材は自重による変形などを防止するために軽量かつ高剛性であることが望まれている。長尺中実状（ムク状）では重量が嵩むので、セラミックス製品を中空化（トンネル状）して、軽量化と高剛性化を図っている。 These devices require highly accurate position control, and structural members such as guide rails are desired to be lightweight and highly rigid in order to prevent deformation due to their own weight. Since the weight is increased in the long solid state (much shape), the ceramic product is hollowed out (tunnel shape) to reduce the weight and increase the rigidity.
中空状のセラミックス焼結体の製造方法として、セラミックス焼結体間に、焼結体と同じ組成からなる成形用スラリーを介在させて焼成することにより、接合させる方法（例えば、特許文献１参照）、及び、坏土を中空形状に付与可能な金型から押し出して中空状のセラミックス成形体を連続的に形成し、得られたセラミックス成形体を焼成する方法（例えば、特許文献２参照）がある。 As a method for producing a hollow ceramic sintered body, a method is performed in which a molding slurry having the same composition as that of the sintered body is interposed between the ceramic sintered bodies and fired (for example, see Patent Document 1). In addition, there is a method of continuously forming a hollow ceramic molded body by extruding a clay from a mold capable of imparting a hollow shape, and firing the obtained ceramic molded body (for example, see Patent Document 2). .
しかし、セラミックス焼結体同士を焼成して接合すると、接合界面に空隙が存在するため、局所的な剛性低下が発生するという問題がある。一方、押し出し成形で得られたセラミックス成形体は、成形体強度が不足するため、中空状の維持が困難であり、また、成形体内部で粒子が配向するため、焼成時の変形が大きくクラックが発生するという問題がある。 However, there is a problem in that when the ceramic sintered bodies are sintered and joined together, voids are present at the joining interface, resulting in a local reduction in rigidity. On the other hand, the ceramic molded body obtained by extrusion molding is difficult to maintain a hollow shape due to insufficient molded body strength, and because the particles are oriented inside the molded body, deformation during firing is large and cracks are generated. There is a problem that occurs.
そこで、石膏からなる中子を配置した鋳型にスラリーを流し込んで鋳込み成形により中空状のセラミックス成形体を形成し、得られた成形体を焼成して中空状のセラミックス焼結体を製造する方法がある。 Therefore, there is a method for producing a hollow ceramic sintered body by pouring slurry into a mold having a gypsum core and forming a hollow ceramic molded body by casting, and firing the obtained molded body. is there.
しかしながら、石膏からなる中子を備えた鋳型を用いて鋳込み成形すると、セラミックス成形体を乾燥させるとき、中空部が収縮して中子を抱きかかえた状態となり、中空部にクラックが発生するという問題がある。 However, when casting is performed using a mold having a core made of gypsum, when the ceramic molded body is dried, the hollow portion contracts to hold the core, and cracks are generated in the hollow portion. There is.
本発明は、以上の点に鑑み、鋳込み成形したセラミックス成形体の乾燥時にクラックが発生することを防止して、中空状のセラミックス製品を安定して製造可能な方法を提供するものである。 In view of the above points, generation of cracks during drying of the cast molded ceramic molded body by preventing and provides a way capable producing hollow ceramic products stably.
本発明のセラミックス製品の製造方法は、少なくとも底部が吸水性材料からなる主型と、少なくとも表面層がショア硬度Ａ(ＪＩＳ)２０〜６０°の柔軟材料からなり、表面粗さＲａが４．０μｍ以下であり、中空部を形成するための中子とを備える鋳型に、セラミックス粉末を分散させたスラリーを注入する工程と、前記スラリーの水分を前記吸水性材料に吸水させると共に、前記セラミックス粉末を前記鋳型に着肉させ、セラミックス成形体を形成する工程とを含むことを特徴とする。 The method for producing a ceramic product of the present invention comprises a main mold having at least a bottom part made of a water-absorbing material, and at least a surface layer made of a flexible material having a Shore hardness A (JIS) of 20 to 60 °, and a surface roughness Ra of 4.0 μm. Ri der hereinafter, a mold and a core for forming the hollow portion, and the step of injecting a slurry prepared by dispersing a ceramic powder, dissipate water water of the slurry in the water-absorbing material, the ceramic powder And a step of forming a ceramic molded body.
本発明のセラミックス製品の製造方法によれば、セラミックス成形体の中空部に接する中子の表面層がショア硬度Ａ(ＪＩＳ)２０〜６０°の柔軟材料からなっている。そのため、セラミックス成形体の乾燥時、中空部が収縮して中子を抱きかかえた状態になったとき、中空部は表面層から反力を受けず比較的自由に収縮できる。よって、乾燥時にクラックが発生するおそれが低減され、セラミックス成形体を安定して製造することができる。 According to the method for producing a ceramic product of the present invention, the surface layer of the core in contact with the hollow portion of the ceramic molded body is made of a flexible material having a Shore hardness A (JIS) of 20 to 60 °. For this reason, when the ceramic molded body is dried, when the hollow portion contracts to hold the core, the hollow portion can be relatively freely contracted without receiving a reaction force from the surface layer. Therefore, the possibility that cracks are generated during drying is reduced, and the ceramic molded body can be manufactured stably.
さらに、セラミックス成形体の中空部に接する中子の表面粗さＲａが４．０μｍ以下であるので、転写される中空部の表面粗さが細かくなり、空隙も少なくなる。よって、セラミックス成形体を焼成したときに、クラック、反り、変形などが生じるおそれが低減され、セラミックス製品を安定して製造することができる。また、中空部の内面性状に高精度な平滑性が得られ、切削加工などの生加工を中空部の内面に施す必要がなく、製造コストを削減することができる。 Furthermore, since the surface roughness Ra of the core in contact with the hollow portion of the ceramic molded body is 4.0 μm or less, the surface roughness of the hollow portion to be transferred becomes fine and the voids are reduced. Therefore, when a ceramic molded body is fired, the risk of cracks, warpage, deformation, and the like is reduced, and a ceramic product can be stably manufactured. Moreover, highly accurate smoothness is obtained in the inner surface property of the hollow portion, and it is not necessary to perform raw processing such as cutting on the inner surface of the hollow portion, thereby reducing the manufacturing cost.
本発明の実施形態に係るセラミックス製品の製造方法で用いられる鋳型（成形型）１０について、主に図１（ａ）及び図１（ｂ）を参照して説明する。 For the mold (mold) 10 for use in the method of manufacturing a ceramic product according to implementation embodiments of the present invention will be mainly described with reference to FIGS. 1 (a) and 1 (b).
鋳型１０は、鋳込み成形法により中空状のセラミックス成形体２２（図２（ｃ）参照）を形成する場合に使用され、主型１１と中子（中型）１２とからなる。 The mold 10 is used when a hollow ceramic molded body 22 (see FIG. 2C) is formed by a casting molding method, and includes a main mold 11 and a core (medium mold) 12.
主型１１は、吸水性材料からなる底部１１ａ、非吸水性材料からなる側壁部１１ｂ、及び底部１１ａが上面に配置される底板１１ｃを備えている。側壁部１１ｂと底板１１ｃとの連結部は、気密性が維持できるように接着されている。 The main mold 11 includes a bottom portion 11a made of a water absorbent material, a side wall portion 11b made of a non-water absorbent material, and a bottom plate 11c on which the bottom portion 11a is disposed on the upper surface. The connecting portion between the side wall portion 11b and the bottom plate 11c is bonded so that airtightness can be maintained.
底部１１ａは、多孔質体などの吸水性材料からなり、鋳込み成形で一般的に使用される石膏からなることが好ましい。ただし、底部１１ａは、エポキシやポリエステル等の樹脂、セラミックスや金属等からなる多孔体などからなるものであってもよい。側壁部１１ｂは、ステンレス鋼等の金属や塩化ビニル等の硬質プラスチックなどの非吸水性材料からなる。なお、側壁部１１ｂは吸水性材料からなるものであってもよい。底板１１ｃは、側壁部１１ｂと同様の非吸水性材料であることが好ましいが、これに限定されない。 The bottom 11a is preferably made of a water-absorbing material such as a porous body, and is preferably made of gypsum generally used in casting. However, the bottom portion 11a may be made of a resin such as epoxy or polyester, a porous body made of ceramics, metal, or the like. The side wall 11b is made of a non-water-absorbing material such as a metal such as stainless steel or a hard plastic such as vinyl chloride. In addition, the side wall part 11b may consist of a water absorbing material. The bottom plate 11c is preferably a non-water-absorbing material similar to the side wall portion 11b, but is not limited thereto.
底部１１ａの下側部に気密空間１３が形成されていることが好ましい。気密空間１３は、トンネル状等の溝や穴からなるものであり、図示しない真空ポンプなどの真空源によってその空間内が減圧されるように構成されている。 It is preferable that an airtight space 13 is formed in the lower portion of the bottom portion 11a. The airtight space 13 is composed of a tunnel-like groove or hole, and is configured such that the space is decompressed by a vacuum source such as a vacuum pump (not shown).
中子１２は、少なくともその表面層１２ａがショア硬度Ａ(ＪＩＳ)２０〜６０°の柔軟材料からなるものであり、その表面粗さＲａが４．０μｍ以下である。このような柔軟材料としては、例えば、ウレタンゴム、シリコンゴム、クロロプレンゴムなどの合成ゴムを用いることができる。なお、中子１２は、全体が柔軟材料からなるものでも、表面層１２ａのみが柔軟材料からなるものであってもよい。なお、表面層１２ａのみが柔軟材料からなる場合、表面層１２ａの厚みは、後述するセラミックス成形体２２（図２（ｃ）参照）の乾燥時の収縮量に応じて適宜定めればよい。 The core 12 has at least a surface layer 12a made of a flexible material having a Shore hardness A (JIS) of 20 to 60 °, and has a surface roughness Ra of 4.0 μm or less. As such a flexible material, for example, a synthetic rubber such as urethane rubber, silicon rubber, or chloroprene rubber can be used. The core 12 may be entirely made of a flexible material, or only the surface layer 12a may be made of a flexible material. In the case where only the surface layer 12a is made of a flexible material, the thickness of the surface layer 12a may be appropriately determined according to the shrinkage amount when the ceramic molded body 22 (see FIG. 2C) described later is dried.
ここでは、４つの中子１２が、縦断面同一で鋳型１０の長手方向に沿って直線状に延びている。各中子１２は、ステンレス鋼等の硬質材料からなる芯部１２ｂと、芯部１２ｂの表面を覆うように形成され、柔軟材料からなる表面層１２ａとから構成されている。 Here, the four cores 12 have the same longitudinal section and extend linearly along the longitudinal direction of the mold 10. Each core 12 includes a core portion 12b made of a hard material such as stainless steel and a surface layer 12a made of a flexible material so as to cover the surface of the core portion 12b.
そして、各中子１２は、その両端部が両側壁１１ｂに形成された穴に嵌合すると共に、ボルト１４で側壁１１ｂに固定されたプレート１５によって保持されている。プレート１５を用いることにより、中子１２と側壁１１ｂとの接続部からスラリー２１（図２（ａ）参照）が漏洩することが防止される。 And each core 12 is hold | maintained by the plate 15 fixed to the side wall 11b with the volt | bolt 14 while fitting the both ends to the hole formed in the both-sides wall 11b. By using the plate 15, the slurry 21 (see FIG. 2A) is prevented from leaking from the connecting portion between the core 12 and the side wall 11b.
以下、本発明のセラミックス製品の製造方法の鋳型１０を用いた実施形態について、主として図２（ａ)〜図２（ｄ）を参照して説明する。 Hereinafter, an embodiment using the mold 10 of the method for producing a ceramic product of the present invention will be described mainly with reference to FIGS. 2 (a) to 2 (d).
まず、鋳型１０に注入するスラリー（泥漿）２１（図２（ａ）参照）を用意する。スラリー２１は、セラミックス粉末、分散剤、バインダ、溶媒などから構成される。セラミックス粉末としては、アルミナ粉末であることが好ましいが、炭化珪素、窒化珪素、ジルコニア、スピネル、イットリアなどからなる各種のセラミック粉末であってもよい。分散剤は、ポリカルボン酸系など公知のものである。溶媒は、水、特に不純物が少ないイオン交換水であることが好ましいが、アルコールなど公知の溶媒を用いることができる。バインダは、ポリビニルアルコールやアクリルエマルジョンなどの公知のものである。また、必要に応じて、ｐＨ調整剤や消泡剤等の添加剤を添加してもよい。 First, a slurry (sludge) 21 (see FIG. 2A) to be injected into the mold 10 is prepared. The slurry 21 is composed of ceramic powder, a dispersant, a binder, a solvent, and the like. The ceramic powder is preferably alumina powder, but may be various ceramic powders made of silicon carbide, silicon nitride, zirconia, spinel, yttria and the like. The dispersant is a known one such as a polycarboxylic acid type. The solvent is preferably water, particularly ion-exchanged water with few impurities, but a known solvent such as alcohol can be used. The binder is a known one such as polyvinyl alcohol or acrylic emulsion. Moreover, you may add additives, such as a pH adjuster and an antifoamer, as needed.
セラミックス粉末、分散剤、溶媒などを１８時間〜２４時間混合してスラリー化し、これにバインダを添加して１時間〜２時間再混合して調整することにより、スラリー２１を得る。 A ceramic powder, a dispersant, a solvent, and the like are mixed to form a slurry by mixing for 18 hours to 24 hours, and a binder is added thereto and remixed for 1 hour to 2 hours to adjust to obtain a slurry 21.
そして、図２（ａ）に示すように、スラリー２１を鋳型１０に注入し、その後、真空吸引することにより、成形を行う。なお、真空吸引は０．０ＭＰａ〜−０．１ＭＰａの真空度（ゲージ圧）の範囲で調整する。 And as shown to Fig.2 (a), it shape | molds by inject | pouring the slurry 21 into the casting_mold | template 10 and vacuum-sucking after that. The vacuum suction is adjusted in the range of a vacuum degree (gauge pressure) of 0.0 MPa to -0.1 MPa.
図２（ｂ）に示すように、吸水材料からなる底部１１ａがスラリー２１中の水分を吸水すると共に、セラミックス粉末が鋳型１０に着肉して、着肉層２２が形成される。時間経過に伴い、着肉層２２の厚みは増加し、着肉層２２の上方には余剰スラリー２３が蓄積する。 As shown in FIG. 2B, the bottom 11a made of a water-absorbing material absorbs moisture in the slurry 21, and the ceramic powder is attached to the mold 10 to form the inking layer 22. As time elapses, the thickness of the inking layer 22 increases, and excess slurry 23 accumulates above the inking layer 22.
その後、着肉層２２が所定厚みを超えたとき、図２（ｃ）に示すように、着肉層２２上にある余剰スラリー２３を排出して、着肉層２２を鋳型１０と共に室温下で数日乾燥させた。なお、真空吸引して着肉を行い、上澄みスラリーを排出、もしくは上澄みスラリーを全量吸水してもよく、着肉後、真空吸引を継続してもよい。また、強制乾燥、もしくは大気開放して乾燥してもよい。 Thereafter, when the thickness of the inking layer 22 exceeds a predetermined thickness, as shown in FIG. 2 (c), the surplus slurry 23 on the inking layer 22 is discharged and the inking layer 22 together with the mold 10 at room temperature. Dried for several days. It should be noted that the suction is performed by vacuum suction and the supernatant slurry is discharged, or the entire amount of the supernatant slurry may be absorbed, or the vacuum suction may be continued after the deposition. Moreover, you may dry by forced drying or air release.
乾燥後、着肉層２２を主型１１から抜き取って脱型する。これにより、着肉層からなるセラミックス成形体２２が得られる。その後、セラミックス成形体２２を乾燥機内で強制乾燥する。なお、この段階で、セラミックス成形体２２から中子１２又は芯部１２ｂのみを抜き取ってもよい。 After drying, the inking layer 22 is extracted from the main mold 11 and removed. Thereby, the ceramic molded body 22 which consists of a walled layer is obtained. Thereafter, the ceramic molded body 22 is forcibly dried in a dryer. At this stage, only the core 12 or the core portion 12b may be extracted from the ceramic molded body 22.
セラミックス成形体（着肉層）２２は乾燥時に収縮し、その中空部が中子１２を抱きかかえた状態になる。しかし、中空部に接する中子１２の表面層１２ａは、ショア硬度Ａ(ＪＩＳ)２０〜６０°の柔軟材料からなり、乾燥による中空部の収縮量に応じた厚みを有している。そのため、中空部は反力を受けず比較的自由に収縮できる。よって、乾燥収縮時に中空部にクラックが発生するおそれを低減することができ、長尺など大型のセラミックス成形体２２を安定して得ることができる。 The ceramic molded body (filled layer) 22 shrinks during drying, and the hollow portion is in a state of holding the core 12. However, the surface layer 12a of the core 12 in contact with the hollow portion is made of a flexible material having a Shore hardness A (JIS) of 20 to 60 ° and has a thickness corresponding to the amount of shrinkage of the hollow portion due to drying. Therefore, the hollow portion can be relatively freely contracted without receiving a reaction force. Therefore, the possibility that cracks are generated in the hollow portion during drying shrinkage can be reduced, and a large ceramic molded body 22 such as a long one can be obtained stably.
さらに、セラミックス成形体２２の中空部に接する中子１２の表面層１２ａの表面粗さＲａが４．０μｍ以下と細かいので、転写される中空部の表面粗さが細かくなり、空隙も少なくなる。よって、後述する焼成時に、クラック、反り、変形などが生じるおそれを低減することができる。また、中空部の内面性状に高精度な平滑性が得られ、切削加工などの生加工を中空部の内面に施す必要がなく、製造コストを削減することができる。 Further, since the surface roughness Ra of the surface layer 12a of the core 12 in contact with the hollow portion of the ceramic molded body 22 is as fine as 4.0 μm or less, the surface roughness of the transferred hollow portion becomes fine and the voids are reduced. Therefore, it is possible to reduce the possibility of cracks, warpage, deformation and the like during firing, which will be described later. Moreover, highly accurate smoothness is obtained in the inner surface property of the hollow portion, and it is not necessary to perform raw processing such as cutting on the inner surface of the hollow portion, thereby reducing the manufacturing cost.
なお、必要に応じて、セラミックス成形体２２を所望形状に生加工してもよい。 If necessary, the ceramic molded body 22 may be processed into a desired shape.
その後、セラミックス生成体２２を、公知の焼成方法で焼成して、図２（ｄ）に示すように、セラミックス焼結体２０を得る。例えば、セラミックス成形体２２を酸化雰囲気で１５００℃〜１６００℃の温度で常圧焼成する。ここで、セラミックス成形体２２は、中子１２を内部に抱えたまま焼成され、焼成中に表面層１２ａを焼失させてもよい。このとき、表面層１２ａはセラミックス成形体２２の空隙を介しても外部に抜け出す。 Thereafter, the ceramic product 22 is fired by a known firing method to obtain a ceramic sintered body 20 as shown in FIG. For example, the ceramic molded body 22 is fired at normal temperature at a temperature of 1500 ° C. to 1600 ° C. in an oxidizing atmosphere. Here, the ceramic molded body 22 may be fired while holding the core 12 therein, and the surface layer 12a may be burned off during firing. At this time, the surface layer 12 a is pulled out to the outside even through the voids of the ceramic molded body 22.
なお、必要に応じて、セラミックス成形体２２を５００℃程度まで徐々に加熱して内部のバインダを脱脂させてもよい。また、強度を強化するために、セラミックス成形体２２を１０００℃〜１３００℃で仮焼してもよい。 If necessary, the ceramic molded body 22 may be gradually heated to about 500 ° C. to degrease the internal binder. In order to enhance the strength, the ceramic molded body 22 may be calcined at 1000 ° C. to 1300 ° C.
最後に、必要に応じて、所望の寸法となるようにセラミックス焼結体２０に仕上げ加工を施す。 Finally, if necessary, the ceramic sintered body 20 is finished so as to have a desired dimension.
なお、以上、本発明の実施形態について図面を参照して説明したが、本発明はこれに限定されない。例えば、中子１２の断面形状は、丸形状や角形状など任意であり、その長手方向に同一でなくともよい。また、中子１２は、直線状に延びるものに限定されず、波状、階段状など任意の形状に延びるもののほか、ブロック状、筒状など任意の形状のものであってもよい。また、中子１２の個数も限定されず、セラミックス成形体２２に任意の個数の中空形状を形成することができる。また、複数の中子１２を組み合わせて、セラミックス成形体２２に複雑な中空形状を形成することもできる。また、中子１２の支持構造も限定されない。 Although the embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to this. For example, the cross-sectional shape of the core 12 is arbitrary, such as a round shape or a square shape, and may not be the same in the longitudinal direction. Further, the core 12 is not limited to a linearly extending shape, and may be of an arbitrary shape such as a block shape or a cylindrical shape in addition to an arbitrary shape such as a wave shape or a staircase shape. Further, the number of the cores 12 is not limited, and an arbitrary number of hollow shapes can be formed in the ceramic molded body 22. Further, a complex hollow shape can be formed in the ceramic molded body 22 by combining a plurality of cores 12. Further, the support structure of the core 12 is not limited.
このように、中子１２の形状、個数、支持構造などが限定されないので、所望するセラミックス製品の重量や剛性などに応じて、自由度の大きな中空形状をセラミックス成形体２２に付与することが可能となる。例えば、角板状、円板状、柱状、棒状などの中子１２を用いて、減肉リブ形状を備えたセラミックス成形体２２を得ることができる。 Thus, since the shape, number, support structure, etc. of the core 12 are not limited, it is possible to impart a hollow shape with a high degree of freedom to the ceramic molded body 22 in accordance with the desired weight and rigidity of the ceramic product. It becomes. For example, a ceramic molded body 22 having a reduced rib shape can be obtained by using a core 12 such as a square plate shape, a disk shape, a column shape, or a rod shape.
また、本発明は、固形鋳込み成形法などに比較すると、成形可能なセラミックス成形体２２の大きさに制約が少なく、小型品から大型品まで適用できる。特に、一辺が４００ｍｍ以上、又は直径３００ｍｍ以上で、肉厚が４０ｍｍ以上の大型肉厚形状のセラミックス成形体２２を形成するに適している。 Further, the present invention has less restrictions on the size of the ceramic molded body 22 that can be molded compared to a solid cast molding method, and can be applied from a small product to a large product. In particular, it is suitable for forming a large-sized thick ceramic formed body 22 having a side of 400 mm or more or a diameter of 300 mm or more and a thickness of 40 mm or more.
また、例えば、中実円柱状の中子を底部１１ａの載置することにより、鉛直方向に延びる円柱状の穴が形成された肉厚円筒状のセラミックス成形体２２を得ることができる。 Further, for example, by placing a solid cylindrical core on the bottom 11a, a thick cylindrical ceramic molded body 22 in which a cylindrical hole extending in the vertical direction is formed can be obtained.
また、主型１１に注入したスラリー２１中にブロック状の中子１２を埋め込むことにより、外部と連通しない空洞を有したセラミックス成形体２２を得ることができる。この場合、中子１２を全て柔軟材料からなるものとして、焼成の際に中子１２を全て焼失させればよい。 Further, by embedding the block-shaped core 12 in the slurry 21 injected into the main mold 11, a ceramic molded body 22 having a cavity that does not communicate with the outside can be obtained. In this case, all the cores 12 may be made of a flexible material, and all the cores 12 may be burned off during firing.
また、中子１２の成形空間に対する体積割合は５％〜９５％の範囲であればよく、セラミックス成形体２２の肉厚の薄厚も限定されない。
また、本発明は、加圧鋳込みや固形鋳込みにも適用可能である。
Moreover, the volume ratio with respect to the shaping | molding space of the core 12 should just be the range of 5%-95%, and the thin thickness of the ceramic molded object 22 is not limited.
The present invention is also applicable to pressure casting and solid casting.
〔実施例及び比較例〕
セラミックス製品がアルミナセラミックス焼結体である場合について、実施例及び比較例を説明する。セラミックス粉末として市販のアルミナ粉末（昭和電工株式会社製ＡＬ−１６０ＳＧ−４、純度９９．７％）を用い、バインダ（三井東圧化学株式会社製ＷＡ−３２０）、分散剤（互応化学工業株式会社製ＫＥ−５５２）及びイオン交換水を混合して調整し、スラリーを作製した。
[Examples and Comparative Examples]
Examples and comparative examples will be described in the case where the ceramic product is an alumina ceramic sintered body. A commercially available alumina powder (AL-160SG-4 manufactured by Showa Denko KK, purity 99.7%) is used as the ceramic powder, a binder (WA-320 manufactured by Mitsui Toatsu Chemical Co., Ltd.), a dispersing agent (Kyoto Chemical Industry Co., Ltd.). KE-552) and ion-exchanged water were mixed and adjusted to prepare a slurry.
鋳型１０として、底部１１ａが石膏、側壁部１１ｂ及び底板１１ｃが硬質プラスチックからなり、主型の内側寸法が幅１１００ｍｍ、深さ５００ｍｍ、奥行き１１００ｍｍであるものを用いた。底部１１ａの下側部には、真空ポンプにより減圧される吸引溝１３が形成されている。４本の中子１２を幅方向に２００ｍｍ、高さ方向に３０ｍｍだけ隙間を設けて、縦２本、横２本に図１（ａ）及び図１（ｂ）に示すように配置した。各中子１２の外側形状は、幅２５０ｍｍ、高さ３０ｍｍ、奥行き１１００ｍｍの四角柱状である。鋳型１０は、底部１１ａの着肉面（上面）が水平になるように水平な場所に設置した。 As the mold 10, a mold was used in which the bottom 11 a was made of gypsum, the side wall 11 b and the bottom plate 11 c were made of hard plastic, and the inner dimensions of the main mold were 1100 mm wide, 500 mm deep, and 1100 mm deep. A suction groove 13 that is decompressed by a vacuum pump is formed on the lower side of the bottom 11a. The four cores 12 were provided with a gap of 200 mm in the width direction and 30 mm in the height direction, and arranged as shown in FIG. 1A and FIG. The outer shape of each core 12 is a quadrangular prism shape having a width of 250 mm, a height of 30 mm, and a depth of 1100 mm. The mold 10 was installed in a horizontal place so that the wall surface (upper surface) of the bottom 11a was horizontal.
次に、この鋳型１０に前述したスラリーを注入した。着肉は、吸引溝１３から吸引する吸引真空力をゲージ圧で０ＭＰａ〜−０．１ＭＰａの範囲で調整しながら行った。着肉厚みが１５０ｍｍに到達したとき、着肉層２２上にある上澄みスラリー２３を排出した。着肉厚みは、着肉層２２の上面に棒を押し当てて測定した。その後、吸引溝１３から吸引する吸引真空力をゲージ圧で−０．１ＭＰａとして所定時間吸水を行った。 Next, the slurry described above was poured into the mold 10. The fleshing was performed while adjusting the suction vacuum force sucked from the suction groove 13 in the range of 0 MPa to −0.1 MPa as a gauge pressure. When the wall thickness reached 150 mm, the supernatant slurry 23 on the wall layer 22 was discharged. The thickness of the inking was measured by pressing a stick against the upper surface of the inking layer 22. Thereafter, the suction vacuum force sucked from the suction groove 13 was set to -0.1 MPa as a gauge pressure, and water was absorbed for a predetermined time.
そして、室温下で１４日乾燥し、さらに３０℃〜６０℃まで徐々に加熱して強制乾燥した後、セラミックス成形体２２を主型１１から取り出した。なお、この時点では、中子１２はセラミックス成形体２２内に残置されている。 And it dried at room temperature for 14 days, and also after heating gradually to 30 to 60 degreeC and forced-drying, the ceramic molded object 22 was pick_out | removed from the main type | mold 11. As shown in FIG. At this time, the core 12 is left in the ceramic molded body 22.
次に、セラミックス成形体２２を酸化雰囲気下で常圧焼成した。１６００℃で２時間焼成して、セラミックス焼結体２０を得た。 Next, the ceramic molded body 22 was fired at normal pressure in an oxidizing atmosphere. The ceramic sintered body 20 was obtained by firing at 1600 ° C. for 2 hours.
実施例と比較例の結果を表１にまとめた。なお、硬度は、実施例１〜５及び比較例１，２ではＪＩＳ Ｋ ６２５３に準拠したショア硬度Ａ(ＪＩＳ)、比較例３ではショア硬度Ｄ（ＪＩＳ）、比較例４ではモース硬度、比較例５ではＪＩＳ Ｚ ２２４４に準拠したビッカース硬度での値である。 The results of Examples and Comparative Examples are summarized in Table 1. In Examples 1 to 5 and Comparative Examples 1 and 2, Shore hardness A (JIS) conforming to JIS K 6253, Shore hardness D (JIS) in Comparative Example 3, Mohs hardness in Comparative Example 4, and Comparative Example 5 is a value in Vickers hardness according to JIS Z 2244.
〔実施例１−５〕
ショア硬度Ａ(ＪＩＳ)２０〜６０°で表面粗さＲａが４．０μｍ以下のシリコンゴム、クロロプレンゴム、ウレタンゴム、ブチルゴムからなる表面層１２ａを有する中子１２を備えた鋳型１０を用いて成形した。このとき、得られたセラミックス成形体２２は、何れも、乾燥時にクラックは発生せず、外観目視は良好であり、中空部の表面も平滑であった。その後、中空部に加工を加えることなく、セラミックス成形体２２を焼成した。得られたセラミックス焼結体２０は、何れも外観目視は良好であり、反り、変形、クラックは発生していなかった。そして、嵩密度は３．９０ｇ／ｃｍ３以上であり、良好に緻密化していた。
[Example 1-5]
Molded using a mold 10 having a core 12 having a surface layer 12a made of silicon rubber, chloroprene rubber, urethane rubber, and butyl rubber having a shore hardness A (JIS) of 20 to 60 ° and a surface roughness Ra of 4.0 μm or less. did. At this time, none of the obtained ceramic compacts 22 was cracked during drying, the appearance was good, and the surface of the hollow part was smooth. Thereafter, the ceramic molded body 22 was fired without processing the hollow portion. The obtained ceramic sintered bodies 20 were all visually good in appearance and were not warped, deformed, or cracked. The bulk density was 3.90 g / cm 3 or more, and it was well densified.
〔比較例１〕
ショア硬度Ａ(ＪＩＳ)が１５°のシリコンゴムからなる表面層１２ａを有する中子１２を備えた鋳型１０を用いて成形した。得られたセラミックス成形体２２は、自重と乾燥収縮によって中空部内に変形が生じていた。その後、焼成して得られたセラミックス焼結体２０にはクラックが発生していた。
[Comparative Example 1]
Molding was performed using a mold 10 provided with a core 12 having a surface layer 12a made of silicon rubber having a Shore hardness A (JIS) of 15 °. The obtained ceramic compact 22 was deformed in the hollow part by its own weight and drying shrinkage. Thereafter, cracks occurred in the sintered ceramic body 20 obtained by firing.
〔比較例２〕
表面粗さＲａが１０．０μｍのクロロプレンゴムからなる表面層１２ａを有する中子１２を備えた鋳型１０を用いて成形した。得られたセラミックス成形体２２には所望の中空形状が形成されていたが、中空部の表面粗さが粗く空隙が多く存在することが目視で確認された。これは、中子１２の表面粗さが粗かったためであると考えられる。その後、焼結して得られたセラミックス焼結体２０には、反り、変形、クラックが発生しており、嵩密度は３．７０ｇ／ｃｍ３と低く、十分に緻密化されていなかった。
[Comparative Example 2]
Molding was performed using a mold 10 provided with a core 12 having a surface layer 12a made of chloroprene rubber having a surface roughness Ra of 10.0 μm. Although the desired hollow shape was formed in the obtained ceramic molded body 22, it was visually confirmed that the surface roughness of the hollow portion was rough and there were many voids. This is presumably because the surface roughness of the core 12 was rough. Thereafter, the ceramic sintered body 20 obtained by sintering was warped, deformed, and cracked, and the bulk density was as low as 3.70 g / cm 3 , which was not sufficiently densified.
〔比較例３，４，５〕
ポリエチレン、石膏及びステンレス鋼と、ショア硬度Ａ（ＪＩＳ）が６０°を超える硬い材質からなる中子１２を備えた鋳型１０を用いて成形した。得られたセラミックス成形体２２から中子１２を引き抜くことができず、セラミックス成形体２２にクラックが発生した。
[Comparative Examples 3, 4, 5]
Molding was performed using a mold 10 having a core 12 made of polyethylene, gypsum, stainless steel, and a hard material having a Shore hardness A (JIS) exceeding 60 °. The core 12 could not be pulled out from the obtained ceramic molded body 22, and cracks were generated in the ceramic molded body 22.
１０…鋳型、 １１…主型、 １１ａ…底部、 １１ｂ…側壁部、 １１ｃ…底板、 １２…中子、 １２ａ…表面層、 １２ｂ…芯部、 １３…気密空間（溝）、 ２０…セラミックス製品（セラミックス焼結体）、 ２１…スラリー、 ２２…セラミックス成形体（着肉層）。 DESCRIPTION OF SYMBOLS 10 ... Mold, 11 ... Main type, 11a ... Bottom part, 11b ... Side wall part, 11c ... Bottom plate, 12 ... Core, 12a ... Surface layer, 12b ... Core part, 13 ... Airtight space (groove), 20 ... Ceramic product ( Ceramic sintered body), 21 ... Slurry, 22 ... Ceramic molded body (walled layer).
Claims (1)
前記スラリーの水分を前記吸水性材料に吸水させると共に、前記セラミックス粉末を前記鋳型に着肉させ、セラミックス成形体を形成する工程とを含むことを特徴とするセラミックス製品の製造方法。 To form a hollow part with at least a main mold having a water-absorbing material at the bottom and a soft material having at least a surface layer of Shore hardness A (JIS) 20 to 60 ° and a surface roughness Ra of 4.0 μm or less. Injecting a slurry in which ceramic powder is dispersed into a mold including a core;
And a step of causing the water-absorbing material to absorb moisture of the slurry, and forming the ceramic molded body by depositing the ceramic powder on the mold.
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