JP3450875B2 - Method for producing porous silicon carbide material - Google Patents

Method for producing porous silicon carbide material

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Publication number
JP3450875B2
JP3450875B2 JP10023893A JP10023893A JP3450875B2 JP 3450875 B2 JP3450875 B2 JP 3450875B2 JP 10023893 A JP10023893 A JP 10023893A JP 10023893 A JP10023893 A JP 10023893A JP 3450875 B2 JP3450875 B2 JP 3450875B2
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JP
Japan
Prior art keywords
sic
porous
silicon carbide
mesophase
slurry
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
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JP10023893A
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Japanese (ja)
Other versions
JPH06293575A (en
Inventor
久仁恵 吉田
雄史 堀内
正俊 大西
浩一 井村
Original Assignee
東芝セラミックス株式会社
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
    • C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
    • C04B41/5093—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials with elements other than metals or carbon
    • C04B41/5096—Silicon
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/53—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone involving the removal of at least part of the materials of the treated article, e.g. etching, drying of hardened concrete

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、多孔質炭化珪素材の製
造方法に関し、詳しくは、その骨格が緻密質炭化珪素か
ら形成される多孔質炭化珪素材の製造方法に関する。BACKGROUND OF THE INVENTION The present invention relates to a manufacturing <br/> method for producing a porous silicon carbide material and, more particularly, to a method for producing a porous silicon carbide material whose skeleton is formed from a dense silicon carbide.

【０００２】[0002]

【従来の技術】炭化珪素（ＳｉＣ）材料は、機械的強
度、耐熱性、耐食性、硬度等に優れ各種材料として用い
られている。ＳｉＣ材を多孔質体に形成し、その優れた
特性から種々の用途への適用が試みられている。多孔質
ＳｉＣの製法としては、例えば、特公昭６１−５２１０
７号公報には、所定の形状に成形した炭素成形体、また
は、炭素及びＳｉＣからなる成形体を非酸化性雰囲気下
で珪素（Ｓｉ）を含浸させ、その後、酸素含有ガス雰囲
気で焼成して未反応炭素を燃焼除去し、所定形状を保持
したＳｉＣが三次元網目状に結合した多孔質ＳｉＣの成
形体が提案されている。2. Description of the Related Art Silicon carbide (SiC) materials are used as various materials because of their excellent mechanical strength, heat resistance, corrosion resistance and hardness. It has been attempted to form a SiC material into a porous body and apply it to various uses because of its excellent characteristics. As a method for producing porous SiC, for example, Japanese Patent Publication No. 61-5210.
No. 7, gazette discloses that a carbon compact molded into a predetermined shape or a compact composed of carbon and SiC is impregnated with silicon (Si) in a non-oxidizing atmosphere, and then fired in an oxygen-containing gas atmosphere. A porous SiC molded body has been proposed in which unreacted carbon is burned and removed, and SiC having a predetermined shape is bonded in a three-dimensional mesh.

【０００３】また、特開昭６２−２９７２７９号公報で
は、平均粒径５０〜３００μｍのＳｉＣ粒子表面に炭化
性有機化合物を被覆し、その被覆ＳｉＣ粒子粉末を用い
嵩密度が１．７〜２．１ｇ／ｃｍ3 となるようにして成
形体を形成した後、非酸化性雰囲気下で焼成し、Ｓｉを
含浸させ多孔質ＳｉＣを得る方法が提案されている。更
にまた、特開平２−３４５８２号公報には、ＳｉＣ粒子
表面に炭化性有機化合物を被覆し、その被覆ＳｉＣ粉末
を用い成形体を形成した後、非酸化性雰囲気下で焼成
し、次いで、粒子表面上の生成炭化物と溶融Ｓｉを反応
させてＳｉＣを形成させ、未反応Ｓｉを除去した後、更
に炭化性有機物とＳｉ粒子含有分散液を付着させ、炭化
性有機物を炭化した後、加熱処理してＳｉと反応させて
ＳｉＣを形成させＳｉＣ粒子間の結合部を強化させた多
孔質ＳｉＣ材料の製造法が提案されている。Further, in JP-A-62-297279, the surface of SiC particles having an average particle size of 50 to 300 μm is coated with a carbonizing organic compound, and the coated SiC particle powder is used to obtain a bulk density of 1.7 to 2. A method has been proposed in which a molded body is formed to have a concentration of 1 g / cm 3 and then fired in a non-oxidizing atmosphere to impregnate Si to obtain porous SiC. Furthermore, in JP-A-2-34582, the surface of SiC particles is coated with a carbonizing organic compound, a molded body is formed using the coated SiC powder, followed by firing in a non-oxidizing atmosphere, and then the particles. The generated carbide on the surface is reacted with molten Si to form SiC, and unreacted Si is removed. Then, a carbonizable organic substance and a dispersion containing Si particles are further adhered, and the carbonizable organic substance is carbonized, followed by heat treatment. There has been proposed a method for producing a porous SiC material in which SiC is reacted with Si to form SiC to strengthen the bond between SiC particles.

【０００４】[0004]

【発明が解決しようとする課題】しかしながら、上記従
来提案の方法は、粒子の充填空隙を利用した多孔質Ｓｉ
Ｃであって、気孔率を約５０％以上の高率とすることは
難しく、また一方、気孔率を高めるために粒径の大きな
ＳｉＣ粒子を用いた場合は、強度が低下し実用性に乏し
いものとなる。更にまた、上記の提案の他、一般に、多
孔性セラミックスの製造方法として、１）開気孔性多孔
質樹脂にセラミックススラリーを付着し、乾燥、焼結し
て樹脂を焼失させた後、焼結させる方法、２）多孔質樹
脂のプレポリマー中にセラミック原料、発泡剤を混合添
加して発泡し、硬化した後、脱脂焼結する方法、３）セ
ラミック微粒子やセラミックスラリーに、昇華性、可燃
性、溶解性物質の粒子径を制御した粒子を添加混合した
成形した後、これらを除去して焼結する方法等が知られ
る。しかし、いずれも高強度のものや微細気孔径のもの
を作製することができず、また、閉気孔の多孔体の作製
が難しい。本発明は、上記したような現況に鑑み、高気
孔率であって、且つ、高強度の多孔質ＳｉＣ材の簡便な
製造方法の提供を目的とする。However, according to the above-mentioned method proposed in the related art, porous Si using the filling voids of particles is used.
C, it is difficult to make the porosity as high as about 50% or more. On the other hand, when SiC particles having a large particle size are used to increase the porosity, the strength is lowered and the practicality is poor. Will be things. Further, in addition to the above-mentioned proposal, generally, as a method for producing a porous ceramic, 1) a ceramic slurry is attached to an open-pore porous resin, dried and sintered to burn off the resin, and then sintered. Method 2) Method of mixing and adding a ceramic raw material and a foaming agent to a prepolymer of a porous resin, foaming, curing and then degreasing and sintering 3) Sublimation, flammability, There is known a method in which particles having a controlled particle diameter of a soluble substance are added and mixed, molded, and then removed to sinter. However, none of them can produce a high-strength one or one having a fine pore size, and it is difficult to produce a porous body having closed pores. In view of the present situation as described above, the present invention aims to provide a simple method for producing a porous SiC material having a high porosity and a high strength.

【０００５】[0005]

【課題を解決するための手段】本発明によれば、メソフ
ェーズ含有ピッチで被覆されてなる炭化珪素粉末及び溶
媒とからなるスラリーに起泡剤を添加し、機械的に撹拌
することにより気泡を生成し、該気泡含有スラリーを用
いて鋳込み成形により成形体を形成し、該成形体を非酸
化性雰囲気下に乾燥及び焼成した後、珪素を含浸させ、
次いで、未反応珪素を除去することを特徴とする多孔質
炭化珪素材の製造方法が提供される。According to the invention, the method
Silicon carbide powder and melt coated with a waze-containing pitch
Add a foaming agent to the slurry consisting of a medium and mechanically stir
To generate bubbles and use the bubble-containing slurry
To form a molded body by cast molding, and
After drying and firing in a chemical atmosphere, impregnate with silicon,
Next, a porous material characterized by removing unreacted silicon
A method of manufacturing a silicon carbide material is provided.

【０００６】[0006]

【０００７】[0007]

【作用】本発明は上記のように構成され、原料にメソフ
ェーズ含有ピッチにより被覆された微細なＳｉＣ粉末と
溶媒とでスラリーを形成し、そのスラリー中に均一に微
細泡を安定的に分散形成させ、そのスラリーを成形用原
料として用いるため、得られる成形体は、カーボン質成
分のメソフェーズ含有ピッチを表面に有する各ＳｉＣ粉
末粒子と微細泡とが均一に分散した形態で保持されて形
成される。従って、得られた多孔質成形体を焼成するこ
とにより、メソフェーズ含有ピッチがカーボン化し、微
細気泡を分散保持しつつＳｉＣ粒子の結合はそのカーボ
ン質を介して緊密となり、ＳｉＣ中に閉微細気泡とカー
ボン質が均一に分散された状態の多孔質ＳｉＣ−Ｃ焼成
体を得ることができる。このＳｉＣ−Ｃ焼成体にＳｉを
含浸させ骨格を構成する原料ＳｉＣ粒子表面のカーボン
質をＳｉＣに変換し原料ＳｉＣ粒子と共に一体化して、
骨格強度を強化して高密度で、緻密で強固な骨格を形成
することができる。更にまた、同時に未反応のＳｉ分及
び／またはカーボン分を除去することにより、スラリー
中の微細気泡と共に相乗的に５０〜９０％の高気孔率で
高強度の多孔質ＳｉＣを得ることができる。The present invention is configured as described above, and a slurry is formed from a fine SiC powder coated with a mesophase-containing pitch as a raw material and a solvent, and fine bubbles are uniformly dispersed and stably formed in the slurry. Since the slurry is used as a raw material for molding, the obtained molded body is formed by holding each SiC powder particles having the mesophase-containing pitch of the carbonaceous component on the surface and fine bubbles in a uniformly dispersed state. Therefore, by firing the obtained porous molded body, the mesophase-containing pitch is carbonized, and while the fine bubbles are dispersed and held, the bonding of the SiC particles becomes tight through the carbonaceous material, and the closed fine bubbles are formed in the SiC. It is possible to obtain a porous SiC-C fired body in which carbon is uniformly dispersed. By impregnating this SiC-C fired body with Si, the carbonaceous material on the surface of the raw material SiC particles forming the skeleton is converted into SiC and integrated with the raw material SiC particles,
The skeleton strength can be enhanced to form a dense, dense and strong skeleton. Furthermore, by simultaneously removing unreacted Si content and / or carbon content, it is possible to synergistically obtain a high strength porous SiC with a high porosity of 50 to 90% together with fine bubbles in the slurry.

【０００８】以下、本発明について詳細に説明する。本
発明において、メソフェーズ含有ピッチで被覆されたＳ
ｉＣとしては、例えば、特開昭６１−１３６９０６号や
同６４−７５５６６号公報に記載され方法等により、所
定粒径のＳｉＣ粒子とメソフェーズピッチ前駆体とを処
理して製造されるものを用いることができる。この場
合、ＳｉＣ粒子表面に被覆されるメソフェーズ含有ピッ
チは、通常、ＳｉＣに対し０．１〜５重量が被覆され
る。これらＳｉＣ粒子に被覆されたメソフェーズ含有ピ
ッチは、用いるメソフェーズピッチ前駆体を選択するこ
とにより、焼成工程等において重金属やアルカリ成分を
放出することがなく、炭化収率を高く、好ましくは９０
％以上にすることができる。また、ＳｉＣ粒子との密着
性がよく、且つ、各ＳｉＣ粒子表面をほぼ均一に被覆さ
れる。また、ＳｉＣ粒子径及び処理条件等を適宜選択す
ることにより、メソフェーズ含有ピッチの被覆層の厚さ
を所定に制御することもできることが知られている。Ｓ
ｉＣ粒子にピッチ等の炭化性物を被覆する方法は、上記
の他、例えば、炭化性物の溶液とＳｉＣ粒子とを攪拌混
合し更に攪拌しつつ加熱乾燥して被覆する方法、ＳｉＣ
粒子で形成された流動層を加熱しつつピッチ等を供給し
て被覆する方法等が知られているが、ＳｉＣ粒子と炭化
性物との結合が弱く、スラリー形成時に剥離のおそれが
あり好ましくない。The present invention will be described in detail below. In the present invention, S coated with mesophase-containing pitch
As the iC, for example, one produced by treating SiC particles having a predetermined particle diameter and a mesophase pitch precursor by the method described in JP-A-61-136906 or JP-A-64-75566 is used. You can In this case, the mesophase-containing pitch coated on the surface of the SiC particles is usually coated with 0.1 to 5 weight of SiC. The mesophase-containing pitch coated with these SiC particles has a high carbonization yield, preferably 90%, by not selecting a mesophase pitch precursor to be used and releasing a heavy metal or an alkaline component in the firing step or the like.
% Or more. Further, the adhesion with the SiC particles is good, and the surface of each SiC particle is covered almost uniformly. It is also known that the thickness of the coating layer of the mesophase-containing pitch can be controlled to a predetermined value by appropriately selecting the SiC particle size, the processing conditions, and the like. S
Other than the above, the method for coating the iC particles with a carbonaceous material such as pitch is, for example, a method in which a solution of the carbonic material and SiC particles are stirred and mixed, and further dried by heating while stirring, and SiC is coated.
A method of supplying a pitch or the like while heating a fluidized bed formed of particles to coat the particles is known, but the bond between the SiC particles and the carbonized material is weak, and peeling may occur during slurry formation, which is not preferable. .

【０００９】本発明で用いられる上記した公知の方法に
よりメソフェーズ含有ピッチを被覆するための原料Ｓｉ
Ｃ粉末は、その平均粒径が０．１〜１００μｍ、好まし
くは１〜５０μｍのものが用いられる。平均粒径が０．
１μｍ未満であるとメソフェーズ含有ピッチの被覆が困
難となり、また１００μｍを超えると成形、焼成して得
られるＳｉＣ材においてＳｉＣ粒子同士の結合が減少
し、強度が低下するため好ましくない。また、上記原料
ＳｉＣ粉末に被覆されるメソフェーズ含有ピッチの含有
量は、ＳｉＣ粒子表面に被覆する厚みにより調整するこ
とができる。また、原料ＳｉＣ粒子径及びメソフェーズ
含有ピッチの含有量を調整することにより、得られる焼
成体での気孔径や気孔率を制御することができる。通
常、所望１０〜８０重量％、好ましくは１５〜５０重量
％とするのがよい。メソフェーズ含有ピッチの含有量が
１０重量％未満ではＣ分を介したＳｉＣ粒子同士の結合
が弱くなり、８０重量％以上ではＳｉ含浸時に未反応カ
−ボンが残存することとなり不都合を生じるためであ
る。Raw material Si for coating the mesophase-containing pitch by the above-mentioned known method used in the present invention
As the C powder, one having an average particle size of 0.1 to 100 μm, preferably 1 to 50 μm is used. The average particle size is 0.
If it is less than 1 μm, it becomes difficult to cover the mesophase-containing pitch, and if it exceeds 100 μm, the bonding between SiC particles in the SiC material obtained by molding and firing is reduced, which is not preferable. The content of the mesophase-containing pitch coated on the raw material SiC powder can be adjusted by the thickness of the coating on the surface of the SiC particles. Further, by adjusting the raw material SiC particle diameter and the content of the mesophase-containing pitch, it is possible to control the pore diameter and porosity in the obtained fired body. Generally, the desired amount is 10 to 80% by weight, preferably 15 to 50% by weight. If the content of the mesophase-containing pitch is less than 10% by weight, the bond between the SiC particles via the C content is weakened, and if it is 80% by weight or more, unreacted carbon remains at the time of impregnating Si, which causes inconvenience. .

【００１０】本発明において、上記メソフェーズ含有ピ
ッチが被覆されたＳｉＣ粉末は、水、アルコール、アセ
トン等の水性及び非水性の溶媒と共にスラリーを形成
し、更に微細泡を形成した後、次工程の成形工程に供給
する。本発明のスラリーの固形分濃度は、通常の鋳込成
形と同様に７５〜８５重量％に調整すればよく、また、
必要に応じて解膠剤、バインダー等を添加することがで
きる。スラリー中に微細泡の均一な形成は、上記のＳｉ
Ｃ粒子のスラリーに起泡剤を添加し、形成される気泡が
均一に分散安定化されるまで機械的に攪拌することによ
り行うことができる。この場合、上記メソフェーズ含有
ピッチの含有量と併せ、起泡剤の添加量、攪拌時間及び
攪拌強度等を制御することにより得られる成形体及び焼
成体の気孔率を調整することができる。通常は、所望の
気孔率及び成形体形状に合わせ、スラリー粘度を１００
０〜２０００ｃｐで適宜選択し、二頭式攪拌機を用い、
１０分〜２時間攪拌して微細泡を形成分散する。In the present invention, the above-mentioned SiC powder coated with mesophase-containing pitch forms a slurry together with an aqueous or non-aqueous solvent such as water, alcohol or acetone, and further forms fine bubbles, and then is molded in the next step. Supply to the process. The solid content concentration of the slurry of the present invention may be adjusted to 75 to 85% by weight as in ordinary cast molding.
A peptizing agent, a binder and the like can be added if necessary. The uniform formation of fine bubbles in the slurry is due to the above-mentioned Si.
It can be carried out by adding a foaming agent to the slurry of C particles and mechanically stirring until the bubbles formed are uniformly dispersed and stabilized. In this case, it is possible to adjust the porosity of the molded body and the fired body obtained by controlling the amount of the foaming agent added, the stirring time, the stirring strength, etc. together with the content of the mesophase-containing pitch. Generally, the slurry viscosity is adjusted to 100 according to the desired porosity and the shape of the molded body.
Select appropriately from 0 to 2000 cp, using a two-headed stirrer,
Stir for 10 minutes to 2 hours to form and disperse fine bubbles.

【００１１】本発明の成形体は、上記のようにして形成
された微細泡が均一に分散保持されたメソフェーズ含有
ピッチ被覆のＳｉＣ粒子のスラリーを、好ましくは非吸
水性の成形型を用いて、所望形状に鋳込み成形して得る
ことができる。成形体はスラリー中の微細気泡を保持し
て多孔質となる。成形体は、多孔質のまま乾燥され、そ
の後要すれば脱脂処理等をした後、アルゴン、窒素 等
の非酸化性ガス雰囲気下で、約９００〜１８００℃で焼
成処理して、ＳｉＣ表面のメソフェーズ含有ピッチをカ
ーボン化する。本発明のメソフェーズ含有カーボンは加
熱処理により通常９０％以上がカーボン化される。従っ
て、上記多孔質成形体を焼成して形成される多孔性Ｓｉ
Ｃ−Ｃ焼成体は、微細泡を保持しつつ、多孔質焼成体の
骨格を構成する各ＳｉＣ粒子が、その表面のカーボン質
を介して緊密に接合されものとなる。即ち、ＳｉＣ−Ｃ
焼成体は、加熱焼成によりメソフェーズ含有ピッチがカ
ーボンに変化し、骨格部の原料ＳｉＣ粉末粒子表面がカ
ーボンで被覆された形態となる。The molded article of the present invention comprises a slurry of SiC particles coated with mesophase-containing pitch, in which the fine bubbles formed as described above are uniformly dispersed and held, and preferably using a non-water-absorbing mold. It can be obtained by casting into a desired shape. The molded body becomes porous by holding fine bubbles in the slurry. The molded body is dried as it is porous, and if necessary, after degreasing, etc., it is fired at about 900 to 1800 ° C in an atmosphere of non-oxidizing gas such as argon and nitrogen to obtain the mesophase of the SiC surface. Carbonize the contained pitch. 90% or more of the mesophase-containing carbon of the present invention is usually carbonized by heat treatment. Therefore, the porous Si formed by firing the porous molded body is
In the C-C fired body, while holding fine bubbles, the SiC particles constituting the skeleton of the porous fired body are closely bonded via the carbonaceous material on the surface thereof. That is, SiC-C
In the fired body, the mesophase-containing pitch is changed to carbon by heating and firing, and the surface of the raw material SiC powder particles of the skeleton portion is covered with carbon.

【００１２】上記多孔性ＳｉＣ−Ｃ焼成体は、次いで、
アルゴン、窒素等の不活性ガス雰囲気中、または真空中
で、約１４５０℃以上の温度、好ましくは１４５０〜１
７００℃で、Ｓｉ含浸処理される。Ｓｉの含浸は、通
常、溶融Ｓｉと接触することにより行われ、例えば、粉
末状金属Ｓｉ中に焼成体を埋没させた状態で昇温溶融す
る方法、バインダーと共にペースト状とした金属Ｓｉ粉
末で焼成体表面を覆い昇温溶融する方法、金属Ｓｉシー
トを用いて焼成体を包囲して昇温溶融する方法等があ
る。本発明において、上記方法等によりＳｉＣ−Ｃ焼成
体にＳｉを含浸させることにより、溶融Ｓｉが、残留気
孔から多孔性ＳｉＣ−Ｃ焼成体中に侵入し、ＳｉＣ粒子
表面を包囲し各ＳｉＣ粒子間を緊密に結合しているカー
ボンと反応し、新たにＳｉＣを形成する。従って、微細
気泡を有する多孔性焼成体を構成する骨格部は、形成さ
れた新たなＳｉＣと原料ＳｉＣ粉末とが一体化されて補
強強化され、高密度で緻密質、高強度となる。The above-mentioned porous SiC-C fired body is then
In an atmosphere of an inert gas such as argon or nitrogen, or in a vacuum, a temperature of about 1450 ° C. or higher, preferably 1450 to 1
Si impregnation is performed at 700 ° C. The impregnation of Si is usually carried out by contacting with molten Si. For example, a method of heating and melting the sintered body in a powdered metal Si in a state of being embedded therein, a method of firing with a binder-like metallic Si powder together with a binder There are a method of covering the surface of the body and heating and melting, and a method of enclosing the fired body using a metal Si sheet and melting and heating. In the present invention, when the SiC-C fired body is impregnated with Si by the above method or the like, molten Si penetrates into the porous SiC-C fired body through the residual pores, surrounds the surface of the SiC particles, and separates between the SiC particles. Reacts with the carbon that is tightly bound to form new SiC. Therefore, in the skeleton forming the porous fired body having fine cells, the newly formed SiC and the raw material SiC powder are integrated and reinforced, so that the density is high, the density is high, and the strength is high.

【００１３】本発明の多孔質ＳｉＣ材は、上記のＳｉ含
浸後の焼成体から未反応のＳｉ及び／またはカーボン分
を各除去成分の可溶液等で適宜処理することにより除去
して、スラリー中に形成した微細気泡と共に所定の気孔
率を有して形成される。例えば、未反応Ｓｉは、苛性ソ
ーダ、フッ化水素等を用い、また未反応炭素は酸素含有
ガス雰囲気中で加熱処理して除去することができる。本
発明において、上記Ｓｉ含浸処理のＳｉ含浸量により、
焼成体中の未反応カーボン及び未反応Ｓｉの含有量が変
化する。従って、目的に応じてＳｉ含浸量を調整するこ
とにより、それぞれの含有量を制御し、その後の除去処
理を経て気孔径及び気孔率を調整することもできる。The porous SiC material of the present invention is prepared by removing the unreacted Si and / or carbon content from the above-mentioned Si-impregnated fired body by appropriately treating it with a solution of each of the components to be removed, etc. It is formed with a predetermined porosity together with the fine bubbles formed in 1. For example, unreacted Si can be removed by using caustic soda, hydrogen fluoride or the like, and unreacted carbon can be heat-treated in an oxygen-containing gas atmosphere. In the present invention, according to the Si impregnation amount of the Si impregnation treatment,
The content of unreacted carbon and unreacted Si in the fired body changes. Therefore, by adjusting the Si impregnation amount according to the purpose, the respective contents can be controlled, and the pore diameter and the porosity can be adjusted through the subsequent removal treatment.

【００１４】本発明の多孔質ＳｉＣは、上記のように、
スラリーへの添加起泡剤の種類及び添加量、ＳｉＣ粒子
径及びメソフェーズ含有ピッチの被覆量、Ｓｉ含浸量等
の各条件をそれぞれ調整し、更に、微細泡の形成時の攪
拌条件を調整し、気孔径及び気孔率を制御することによ
り、５０％を超える高気孔率とすることができ、且つ、
上記のように製造され、緻密質ＳｉＣの骨格が微細気孔
を均質に分散保持しながら強固に結合されるため高強度
となる。但し、気孔率が９０％以上に形成した場合は、
強度的に実用性に欠けることになり好ましくない。The porous SiC of the present invention, as described above,
The type and addition amount of the foaming agent added to the slurry, the SiC particle size and the coating amount of the mesophase containing pitch, each condition such as the Si impregnated amount is adjusted, and further, the stirring conditions at the time of forming the fine bubbles are adjusted, By controlling the pore size and the porosity, a high porosity exceeding 50% can be achieved, and
Since the dense SiC skeleton manufactured as described above is firmly bonded while uniformly maintaining fine pores, it has high strength. However, when the porosity is 90% or more,
It is not preferable because it lacks practicality in terms of strength.

【００１５】[0015]

【実施例】以下、本発明を実施例に基づき詳細に説明す
る。但し、本発明は下記実施例により制限されるもので
ない。 実施例１ 平均粒径１．０μｍのＳｉＣ粒子をメソフェーズ含有ピ
ッチの含有量が 重量％となるように、平均粒径１．
０μｍのＳｉＣ粉末（昭和電工（株）製）を、エチレン
ヘビーエンドタールのメソフェーズピッチ前駆体で処理
し、それぞれメソフェーズ含有ピッチで被覆されたＳｉ
Ｃ粉末を得た。上記で調製されたメソフェーズ含有ピッ
チで被覆されたＳｉＣ粉末１００重量部に、水２５重量
部、分散剤０．２５重量部及びバインダー１．０重量部
を添加し、ポットミルで混合してスラリーを形成した。
得られたスラリーに起泡剤を１．０重量部添加し、１５
分間攪拌してスラリー中に微細気泡を均一に分散形成し
た。得られた微細泡分散保持したスラリーを、直径１０
０ｍｍφ、厚さ１０ｍｍの円板状に成形した。次いで、
成形体を窒素ガス雰囲気中で、６００℃で１時間保持し
バインダーを離散させて脱脂した。EXAMPLES The present invention will now be described in detail based on examples. However, the present invention is not limited to the following examples. Example 1 SiC particles having an average particle diameter of 1.0 μm were used so that the content of mesophase-containing pitch was 1% by weight.
0 μm SiC powder (manufactured by Showa Denko KK) was treated with a mesophase pitch precursor of ethylene heavy end tar, and each Si was coated with a mesophase containing pitch.
C powder was obtained. To 100 parts by weight of the SiC powder coated with the mesophase-containing pitch prepared above, 25 parts by weight of water, 0.25 parts by weight of a dispersant and 1.0 part by weight of a binder were added and mixed by a pot mill to form a slurry. did.
Add 1.0 part by weight of a foaming agent to the obtained slurry,
After stirring for a minute, fine bubbles were uniformly dispersed and formed in the slurry. The obtained slurry containing fine bubbles dispersed therein was treated with a diameter of 10
It was formed into a disk shape having a diameter of 0 mm and a thickness of 10 mm. Then
The molded body was held in a nitrogen gas atmosphere at 600 ° C. for 1 hour to separate the binder and degrease.

【００１６】脱脂後、アルゴンガス雰囲気中、１８００
℃で１時間焼成して焼成体を得た。得られた焼成体を、
更に、１５００℃アルゴンガス気圧下で、溶融Ｓｉに浸
漬してＳｉを含浸処理した。得られたＳｉ含浸のＳｉＣ
焼成体を、４００℃の溶融水酸化ナトリウム中に浸漬し
て未反応Ｓｉを除去した。得られた多孔質炭化珪素体の
気孔率及び嵩密度を溶液に灯油を用いたアルキメデス法
で、また曲げ強度を３点曲げ試験法で測定した。その結
果、気孔率は６０％、嵩密度は１．３ｇ／ｃｍ3 、曲げ
強度は１００ＭＰａであった。After degreasing, in an argon gas atmosphere, 1800
It baked at 1 degreeC for 1 hour, and obtained the baked body. The obtained fired body,
Furthermore, it was immersed in molten Si at 1500 ° C. under an argon gas pressure to impregnate Si. Obtained Si-impregnated SiC
The fired body was immersed in molten sodium hydroxide at 400 ° C. to remove unreacted Si. The porosity and bulk density of the obtained porous silicon carbide body were measured by the Archimedes method using kerosene in the solution, and the bending strength was measured by the three-point bending test method. As a result, the porosity was 60%, the bulk density was 1.3 g / cm 3 , and the bending strength was 100 MPa.

【００１７】実施例２ 平均粒径が３０μｍのＳｉＣ粒子を用いた以外は、実施
例１と同様にして、多孔質炭化珪素体を得た。得られた
多孔質炭化珪素体の気孔率、嵩密度及び曲げ強度を同様
に測定した。その結果、気孔率は７５％、嵩密度は０．
８ｇ／ｃｍ3 、曲げ強度は３０ＭＰａであった。Example 2 A porous silicon carbide body was obtained in the same manner as in Example 1 except that SiC particles having an average particle size of 30 μm were used. The porosity, bulk density and bending strength of the obtained porous silicon carbide body were measured in the same manner. As a result, the porosity was 75% and the bulk density was 0.
The bending strength was 8 g / cm 3 and the bending strength was 30 MPa.

【００１８】[0018]

【発明の効果】本発明は、メソフェーズ含有ピッチで被
覆されたＳｉＣと溶媒とによりスラリーを形成し、スラ
リー中に微細気泡を安定的に均一分散させて鋳込成形
し、均一且つ均質にカーボン質化合物のメソフェーズ含
有ピッチが配された成形体から多孔性ＳｉＣ−Ｃ焼成体
を得て、カーボンをＳｉＣに変化させ多孔質ＳｉＣの緻
密質骨格を構成するＳｉＣと一体化させて骨格強度を増
大でき、５０％を超える高気孔率を有する多孔質ＳｉＣ
材を得ることができる。INDUSTRIAL APPLICABILITY According to the present invention, a slurry is formed from SiC coated with a mesophase-containing pitch and a solvent, and fine bubbles are stably and uniformly dispersed in the slurry for casting to obtain a uniform and homogeneous carbonaceous material. It is possible to obtain a porous SiC-C fired body from a molded body in which the mesophase-containing pitch of the compound is arranged, convert carbon into SiC, and integrate it with SiC that constitutes the dense skeleton of porous SiC to increase the skeletal strength. , Porous SiC with high porosity over 50%
The material can be obtained.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 井村 浩一 神奈川県秦野市曽屋30 東芝セラミック ス株式会社 開発研究所内 (56)参考文献 特開 平３−215375（ＪＰ，Ａ) 特開 平２−34582（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C04B 35/56 - 35/58 C04B 38/00 - 38/10 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Imura 30 Soya, Hadano-shi, Kanagawa Toshiba Ceramics Co., Ltd. Research and Development Laboratory (56) Reference JP-A-3-215375 (JP, A) JP-A-2-34582 (JP, A) (58) Fields surveyed (Int.Cl. 7 , DB name) C04B 35/56-35/58 C04B 38/00-38/10

Claims (2)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 メソフェーズ含有ピッチで被覆されてな
る炭化珪素粉末及び溶媒とからなるスラリーに起泡剤を
添加し、機械的に撹拌することにより気泡を生成し、該
気泡含有スラリーを用いて鋳込み成形により成形体を形
成し、該成形体を非酸化性雰囲気下に乾燥及び焼成した
後、珪素を含浸させ、次いで、未反応珪素を除去するこ
とを特徴とする多孔質炭化珪素材の製造方法。1. A foaming agent is added to a slurry composed of a silicon carbide powder coated with a mesophase-containing pitch and a solvent.
Adding and mechanically stirring to generate bubbles ,
The molded body is formed by casting using a bubble-containing slurry was dried and fired shaped body in a non-oxidizing atmosphere, impregnated with silicon, then, characterized in that the removal of unreacted silicon porous Of manufacturing a high quality silicon carbide material. 【請求項２】 該炭化珪素粉末が、平均粒子径０．１〜
１００μｍである請求項１記載の多孔質炭化珪素材の製
造方法。2. The silicon carbide powder has an average particle diameter of 0.1 to 0.1.
Porous method of producing a silicon carbide material according to claim 1 wherein the 100 [mu] m.
JP10023893A 1993-04-02 1993-04-02 Method for producing porous silicon carbide material Expired - Fee Related JP3450875B2 (en)

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JP3450875B2 true JP3450875B2 (en) 2003-09-29

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