JPH0224786B2 - - Google Patents
Info
- Publication number
- JPH0224786B2 JPH0224786B2 JP59172128A JP17212884A JPH0224786B2 JP H0224786 B2 JPH0224786 B2 JP H0224786B2 JP 59172128 A JP59172128 A JP 59172128A JP 17212884 A JP17212884 A JP 17212884A JP H0224786 B2 JPH0224786 B2 JP H0224786B2
- Authority
- JP
- Japan
- Prior art keywords
- silicon carbide
- sintering
- sintered body
- porous
- less
- 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 - Lifetime
Links
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 53
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 32
- 238000005245 sintering Methods 0.000 claims description 32
- 239000002245 particle Substances 0.000 claims description 14
- 229910021426 porous silicon Inorganic materials 0.000 claims description 11
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 238000000034 method Methods 0.000 description 11
- 239000000203 mixture Substances 0.000 description 10
- 239000011148 porous material Substances 0.000 description 10
- 238000000465 moulding Methods 0.000 description 7
- 239000000843 powder Substances 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 5
- 229910052796 boron Inorganic materials 0.000 description 5
- 150000003961 organosilicon compounds Chemical class 0.000 description 5
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000011882 ultra-fine particle Substances 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000003054 catalyst Substances 0.000 description 3
- 239000001913 cellulose Substances 0.000 description 3
- 229920002678 cellulose Polymers 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 229920001971 elastomer Polymers 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 239000012188 paraffin wax Substances 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000000921 elemental analysis Methods 0.000 description 2
- 239000001307 helium Substances 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 150000002894 organic compounds Chemical class 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 229920000548 poly(silane) polymer Polymers 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 238000000197 pyrolysis Methods 0.000 description 2
- 150000004756 silanes Chemical class 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- VIPCDVWYAADTGR-UHFFFAOYSA-N trimethyl(methylsilyl)silane Chemical compound C[SiH2][Si](C)(C)C VIPCDVWYAADTGR-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 101150003085 Pdcl gene Proteins 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- XMIJDTGORVPYLW-UHFFFAOYSA-N [SiH2] Chemical compound [SiH2] XMIJDTGORVPYLW-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000012190 activator Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000002390 adhesive tape Substances 0.000 description 1
- 150000001638 boron Chemical class 0.000 description 1
- 150000001639 boron compounds Chemical class 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000009770 conventional sintering Methods 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000000280 densification Methods 0.000 description 1
- UBHZUDXTHNMNLD-UHFFFAOYSA-N dimethylsilane Chemical compound C[SiH2]C UBHZUDXTHNMNLD-UHFFFAOYSA-N 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 125000000816 ethylene group Chemical group [H]C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 239000008240 homogeneous mixture Substances 0.000 description 1
- 150000002430 hydrocarbons Chemical group 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 125000001570 methylene group Chemical group [H]C([H])([*:1])[*:2] 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 150000004686 pentahydrates Chemical class 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 125000000843 phenylene group Chemical group C1(=C(C=CC=C1)*)* 0.000 description 1
- 239000011505 plaster Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 125000001436 propyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000000859 sublimation Methods 0.000 description 1
- 230000008022 sublimation Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- UEUXEKPTXMALOB-UHFFFAOYSA-J tetrasodium;2-[2-[bis(carboxylatomethyl)amino]ethyl-(carboxylatomethyl)amino]acetate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-]C(=O)CN(CC([O-])=O)CCN(CC([O-])=O)CC([O-])=O UEUXEKPTXMALOB-UHFFFAOYSA-J 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Description
（産業上の利用分野）
本発明は多孔質炭化けい素焼結体の製造方法、
特には各種フイルター、触媒担持体、各種薄膜用
支持体として有用とされる多孔質の炭化けい素焼
結体の製造方法に関するものである。
（従来の技術）
炭化けい素の焼結体は化学的、物理的にきわめ
て安定な性質を有しており、特に高温における耐
酸化性、耐蝕性、熱伝導性、強度にすぐれ、熱膨
張係数も低いということから、ガスタービン翼、
自動車用部材、腐蝕性流体用部材、耐火材、高温
反応炉用部材、電気・電子用部材、機械的部材な
どに有用とされているが、これはその使用目的上
から高密度品が要求されるためにこの高密度化焼
結法が種々提案されている。
他方、この炭化けい素は化学的、物理的に安定
な性質をもつていることから高密度化していない
多孔質焼結体に各種フイルター、触媒担持体、各
種薄膜用支持体への応用が期待されているが、従
来の焼結法では均一な孔を有するものを得ること
ができなかつた。
（発明の構成）
本発明はこのような不利を解決した多孔質炭化
けい素焼結体の製造方法に関するものであり、こ
れは結晶子が50Å以下のβ型炭化けい素の集合体
であり、平均粒径が0.01〜1μである球状形状の超
微粒子状β型多結晶炭化けい素に、平均粒径が
6μ以下の多結晶炭化けい素微粉末を混合し、成
形体に成形後焼結炉内に装入して1000〜1750℃ま
では20℃／分以下の昇温速度で加熱し、ついで
1750〜2500℃で焼結してなることを特徴とするも
のである。
これを説明すると、本発明者らはさきに分子中
に少なくとも１個のけい素―水素結合を有する有
機けい素化合物を750℃以上で熱分解させれば粉
砕工程を経ることなしで超微粒子状の炭化けい素
を高純度でしかも収率よく得ることができること
を見出し（特開昭59−39708号公報、特開昭60−
46911号公報、特開昭60−96517号公報参照）、こ
のようにして得た炭化けい素は焼結助剤の添加な
しでも焼結するし、従来公知の炭化けい素との混
合物も極めて微量の焼結助剤で焼結できることを
見出した（特開昭60−46974号公報、特開昭60−
108369号公報参照）。そして、これについてさら
に研究を進めたところ、上記した気相熱分解法で
得られた超微粒子状のβ型炭化けい素に市販され
ている微粉状の炭化けい素を混合して焼結する
と、両者の焼結特性の相違によつてこの焼結体が
多孔質となることを見出すと共に、超微粒子状β
型炭化けい素に混合する炭化けい素の種類、これ
らの配合比を選択し、さらにこの焼結条件として
焼結温度を1750〜2500℃とするが1000℃から1750
℃までの間の昇温速度を20℃／分以下とすれば割
れのない多孔質炭化けい素焼結体を高純度で容易
に得ることができるということを確認して本発明
を完成させた。
本発明による多孔質炭化けい素焼結体を作るた
めの始発材料とされる超微粒子状β型炭化けい素
は有機けい素化合物の気相熱分解反応によつて得
られるが、この有機けい素化合物はその分子中に
少なくとも１個のSi―Ｈ結合を含むものであり、
これは例えば一般式R2o+2（Si）o〔ここにＲはその
少なくとも１個が水素原子であり、その他はメチ
ル基、エチル基、プロピル基、フエニル基、ビニ
ル基などから選ばれる１価の炭化水素基、ｎは１
〜４の正数〕で示されるシランまたはポリシラン
類、および一般式
〔ここにＲは前記と同じ、R′はメチレン基、
エチレン基またはフエニレン基、ｍは１〜２の正
数〕で示されるシルアルキレン化合物またはシル
フエニレン化合物、あるいは同一分子中にこの両
者の主骨格をもつ化合物があげられる。そして、
この有機けい素化合物としては、次式
CH3SiH3、（CH3）2SiH2、（CH3）3SiH、
（C2H5）2SiH2、C3H7SiH3、
CH2＝CH（CH3）SiH2、C6H5SiH3、
(Industrial Application Field) The present invention provides a method for producing a porous silicon carbide sintered body,
In particular, the present invention relates to a method for producing porous silicon carbide sintered bodies useful as various filters, catalyst carriers, and supports for various thin films. (Prior art) Sintered silicon carbide has extremely stable properties chemically and physically, and has excellent oxidation resistance, corrosion resistance, thermal conductivity, and strength, especially at high temperatures, and has a low coefficient of thermal expansion. gas turbine blades,
It is said to be useful for automobile parts, corrosive fluid parts, refractory materials, high-temperature reactor parts, electrical/electronic parts, mechanical parts, etc., but high-density products are required due to the purpose of use. Various densification sintering methods have been proposed to achieve this goal. On the other hand, since silicon carbide has chemically and physically stable properties, it is expected to be applied to non-densified porous sintered bodies for various filters, catalyst supports, and supports for various thin films. However, it has not been possible to obtain a material with uniform pores using conventional sintering methods. (Structure of the Invention) The present invention relates to a method for producing a porous silicon carbide sintered body that solves these disadvantages. The average particle size is spherical ultrafine β-type polycrystalline silicon carbide with a particle size of 0.01 to 1μ.
Polycrystalline silicon carbide fine powder of 6 μ or less is mixed, formed into a compact, charged into a sintering furnace, heated at a temperature increase rate of 20 °C/min or less from 1000 to 1750 °C, and then
It is characterized by being sintered at 1750-2500°C. To explain this, the present inventors found that if an organosilicon compound having at least one silicon-hydrogen bond in its molecule is thermally decomposed at 750°C or higher, it can be turned into ultrafine particles without going through a pulverization process. It was discovered that it was possible to obtain silicon carbide with high purity and good yield (Japanese Patent Application Laid-Open Nos. 59-39708, 1983-
46911, Japanese Patent Application Laid-open No. 60-96517), the silicon carbide thus obtained can be sintered without the addition of a sintering aid, and the amount of mixture with conventionally known silicon carbide is extremely small. It was discovered that sintering can be performed with a sintering aid of
(See Publication No. 108369). Further research on this topic revealed that when commercially available fine powder silicon carbide was mixed with ultrafine β-type silicon carbide obtained by the above-mentioned gas phase pyrolysis method and sintered, It was discovered that this sintered body becomes porous due to the difference in the sintering properties of the two, and it was also discovered that ultrafine particle β
The type of silicon carbide to be mixed with the mold silicon carbide and the mixing ratio of these are selected, and the sintering conditions are set to a sintering temperature of 1750 to 2500℃, but from 1000℃ to 1750℃.
The present invention was completed by confirming that it is possible to easily obtain a crack-free porous silicon carbide sintered body with high purity by setting the temperature increase rate to 20°C/min or less. Ultrafine particulate β-type silicon carbide, which is the starting material for making the porous silicon carbide sintered body according to the present invention, is obtained by a gas phase pyrolysis reaction of an organosilicon compound. contains at least one Si--H bond in its molecule,
This is, for example, the general formula R 2o+2 (Si) o [where R is a monovalent group in which at least one is a hydrogen atom and the others are selected from methyl, ethyl, propyl, phenyl, vinyl, etc. hydrocarbon group, n is 1
silane or polysilane represented by a positive number of ~4], and the general formula [Here, R is the same as above, R' is a methylene group,
Examples include silalkylene compounds or silphenylene compounds represented by an ethylene group or a phenylene group, m being a positive number of 1 to 2, or compounds having both main skeletons in the same molecule. and,
This organosilicon compound has the following formula: CH 3 SiH 3 , (CH 3 ) 2 SiH 2 , (CH 3 ) 3 SiH, (C 2 H 5 ) 2 SiH 2 , C 3 H 7 SiH 3 , CH 2 = CH ( CH3 ) SiH2 , C6H5SiH3 ,
【式】【formula】
【式】【formula】
【式】【formula】
【式】【formula】
【式】【formula】
【式】【formula】
【式】で示されるシラン、
ポリシランが例示され、これらはその１種または
２種あるいは２種以上の混合物として使用される
が、式Silanes and polysilanes represented by the formula are exemplified, and these can be used singly or as a mixture of two or more, but the formula
【式】〔ここにｎは正数〕で示さ
れるジメチルポリシランを350℃以上の温度で熱
分解させて得られるジメチルポリシランを主体と
するメチルハイドロジエンシラン類が好ましいも
のとされる。なお、これらの有機けい素化合物は
従来公知の方法で製造することができるが、これ
らは蒸留工程で容易に高純度化することができ、
粉砕工程が不要なために本反応によつて得られる
炭化けい素は極めて純度の高いものになるという
有利性が与えられる。
この有機けい素化合物の気相熱分解反応はこれ
を750〜1500℃に加熱した反応帯域に水素ガスま
たは窒素、ヘリウム、アルゴンなどの不活性ガス
をキヤリヤーガスとして導入して熱分解させれば
よく、この反応によれば結晶子が50Å以下のβ型
炭化けい素の集合体で、平均粒径が0.01〜1μであ
る球状形状をもつ超微粒子状のβ型多結晶炭化け
い素が得られる。
本発明による多孔質炭化けい素焼結体はこのよ
うにして得た超微粒子状β型炭化けい素に通常市
販されている微粉末状の炭化けい素を混合し焼結
することによつて作られるが、これらの配合比は
超微粒子状β型炭化けい素あるいは微粉末状炭化
けい素が１重量部以下では焼結体が多孔質となら
ないので超微粒状炭化けい素99〜１重量部好まし
くは97〜３重量部に対し市販の微粉状炭化けい素
を１〜99重量部好ましくは３〜97重量部配合する
ことがよい。
また、ここに使用される微粉状炭化けい素は一
般に市販されているα型、β型のいずれであつて
もよく、目的とする多孔質焼結体の孔径を均一と
するためにはできるだけ平均粒径の細かいものと
することがよいが、これには機械的粉砕のために
限度があるし、6μ以上の成分が多くなる（粒度
分布の広いもの）と、孔径も不均一になるので平
均粒径が6μ以下のものとすることがよい。この
ものは結晶子が成長したα、β構造の多結晶体を
粉砕したもののため非球状形状をしており、焼結
温度は前記した超微粉状炭化けい素と異なつた値
を有している。
ここに配合された超微粒子状β型炭化けい素と
微粉状炭化けい素との混合物はついでに成形し焼
結すればよいが、この成形はセラミツク業界で公
知の方法で行えばよく、これは例えばダイプレス
法で行なえばよい。この成形には結合剤として、
加熱により分解生成物が残存しないような有機化
合物、例えばパラフイン、低分子量セルロース誘
導体、フエノール樹脂などを単独で、あるいはア
セトンなどに溶解して使用してもよいがこれら結
合剤を使用せずに直接加圧、成形してもよい。ま
たこれをチユーブ、ルツボなどの複雑な成形品と
するためにはラバープレスなどを用いて成形すれ
ばよいが、より精密な成形品を得るためには生の
賦形体をその焼結前に研削するか、あるいはスラ
イスなどの機械加工を施すことがよい。なお、こ
の成形はスリツプキヤスト法で行なつてもよい
が、この場合には炭化けい素粉末にポリエチレン
グリコール、低分子量セルロース誘導体、パラフ
インなどの可塑剤とポリビニルブチラールなどの
結合剤を添加し、水中に分散させてから焼石こう
型内に流し込めばよい。またセルロース誘導体な
どと水との混合物からなる成形可能なペーストは
押出成形、射出成形、ロール成形などを行なつて
もよい。
このようにして得られた成形体はついで焼結す
ることによつて焼結体とされるが、焼結に先立つ
て添加した有機化合物を揮発させたのち、常圧ま
たは真空下のいずれかの方法で行えばよい。この
加熱温度はこれを1750℃以下とすると焼結不足と
なつて焼結体の強度が低下するほか得られる多孔
質焼結体の孔径が一定にならないという不利が生
じ、2500℃以上とすると粒子の成長によつて多孔
質焼結体の孔がみだれたり、一部に炭化けい素の
昇華によつて粗大孔が発生するので、これは1750
〜2500℃の範囲とする必要があるが、好ましくは
1900〜2300℃の範囲とされる。
しかし、この焼結に当つてはこれが焼結助剤を
添加せず、原材料としての２種の炭化けい素の焼
結速度の差を利用して多孔質焼結体とするもので
あることから、焼結温度である1750℃に到達する
までの昇温速度の選択が重要なものとされる。す
なわち、この昇温速度については1000℃までは比
較的早い、例えば40℃／分としてもよいが、1000
℃以上特に1200℃以上での速い昇温は目的とする
多孔質焼結体に割れを発生させるので、1000℃以
上における昇温速度は20℃／分以下、好ましくは
15℃／分以下とすることが必要とされる。
また、この焼結は窒素、アルゴン、ヘリウムな
どの不活性雰囲気下あるいは真空下とすることが
必要とされるが、この焼結工程に先立つて前記し
た成形品についての切削加工を実施する場合に
は、これを必要に応じて仮焼してもよいが、この
温度は1500℃以下とすることがよく、この温度は
その機械加工に必要とされる強度に応じて定めれ
ばよい。
なお、この焼結時にはこれが超微粒子状β型炭
化けい素と市販品のような微粉状の炭化けい素と
の焼結速度の差を利用して多孔質焼結体を得るも
のであるということから、特に焼結助剤を添加す
る必要はないが、焼結密度をあげ、孔径を小さく
するような目的には焼結助剤としてのほう素を
0.03〜1.0重量部添加してもよい。この焼結助剤
の添加により任意の密度を有する焼結体を得るこ
とができるが、この場合に添加するほう素量は前
記した量と同一とすればよく、このほう素として
は金属ほう素、ほう素化合物のいずれであつても
よい。
これを要するに、本発明は結晶子が50Å以下の
β型炭化けい素集合体で平均粒径が0.01〜1μであ
る球状形状をもつ超微粒子状β型多結晶炭化けい
素と平均粒径が6μ以下の微粉状炭化けい素との
混合物を1750〜2500℃で焼結してなる多孔質炭化
けい素焼結体の製造方法に関するものであるが、
このようにして得られたものは多孔性体であるこ
とから密度は1.70〜2.50ｇ／c.c.となるが、その孔
径が0.05〜100μのほぼ均一な孔径をもつものとさ
れるので各種フイルター、触媒担持体、各種薄膜
用支持体として有用とされる。
つぎに本発明の実施例をあげる。
実施例 １〜８
内径70mm、長さ1500mmのムライト製炉心管を備
えた縦型管状電気炉を1400℃に加熱し、ここにテ
トラメチルジシラン10容量％を含む水素ガスを
200／時で導入して８時間反応させたところ、
炭化けい素粉末525ｇ（収率85％）が得られた。
このものは電子顕微鏡のβ―SiC（１，１，１）
回折による暗視野像の測定結果から50Å以下のβ
型炭化けい素の集合体で平均粒径が0.3〜1μであ
る球状形状もつ超微粒子状のβ型多結晶炭化けい
素で、元素分析値がSi67.1％、C31.8％、BET比
表面積が18.1m2／ｇのものであることが確認され
た。
ついで、この超微粒子状β型多結晶炭化けい素
と市販のβ型炭化けい素・β―ランダム（イビ電
社製商品名、最大粒径6μ）とを第１表に示した
割合になるように、パラフイン１重量％を含むヘ
キサン溶液50c.c.に添加して15分間超音波混合を
行なつたのち、35mm×35mm×10mmの金型に入れて
200Kg／cm2で一次成形し、ラバープレスで1.5ト
ン／cm2の圧力で２次成形した。
つぎにこの成形品を常圧焼結用カーボン炉に入
れ、アルゴンガス雰囲気下で1000℃までは40℃／
分、1000℃以上2100℃までは15℃／分の昇温速度
で昇温させ、2100℃で１時間焼結したところ、得
られた焼結体の密度、酸素透過量について第１表
に併記したとおりの結果が得られた。
なお、実施例６、７は焼結助剤として金属ホウ
素を添加したものであり、この場合には密度増加
に効果のあることが認められる。また参考例は
1000℃以上焼結温度までの昇温速度を40℃／分と
した場合であり、収縮が極めて少なく、密度の増
加も僅かで、焼結体にはクラツクが発生してい
た。Methylhydrodiene silanes mainly composed of dimethylpolysilane obtained by thermally decomposing dimethylpolysilane represented by the formula [where n is a positive number] at a temperature of 350° C. or higher are preferred. Note that these organosilicon compounds can be produced by conventionally known methods, but they can be easily purified to a high degree by a distillation process.
Since no pulverization step is required, the silicon carbide obtained by this reaction has the advantage of being extremely pure. The gas phase thermal decomposition reaction of this organosilicon compound can be carried out by introducing hydrogen gas or an inert gas such as nitrogen, helium, or argon as a carrier gas into a reaction zone heated to 750 to 1500°C. According to this reaction, ultrafine β-type polycrystalline silicon carbide, which is an aggregate of β-type silicon carbide with crystallites of 50 Å or less and has a spherical shape and an average particle size of 0.01 to 1 μm, is obtained. The porous silicon carbide sintered body according to the present invention is produced by mixing the ultrafine particulate β-type silicon carbide thus obtained with commercially available fine powder silicon carbide and sintering the mixture. However, since the sintered body will not become porous if the ultrafine β-type silicon carbide or fine powder silicon carbide is less than 1 part by weight, the blending ratio is preferably 99 to 1 part by weight. It is preferable to mix 1 to 99 parts by weight, preferably 3 to 97 parts by weight, of commercially available fine powder silicon carbide to 97 to 3 parts by weight. In addition, the fine powder silicon carbide used here may be either the α type or β type which is generally commercially available, and in order to make the pore diameter of the porous sintered body uniform, it is necessary to average the pore size as much as possible. It is better to use particles with a fine particle size, but there is a limit to this due to mechanical crushing, and if there are many components with a particle size of 6μ or more (wide particle size distribution), the pore size will become uneven, so the average It is preferable that the particle size is 6μ or less. This product has a non-spherical shape because it is a pulverized polycrystalline body with α and β structures in which crystallites have grown, and its sintering temperature is different from that of the ultrafine silicon carbide described above. There is. The mixture of ultrafine β-type silicon carbide and fine powder silicon carbide blended here may be molded and sintered at the same time, but this molding may be performed by a method known in the ceramic industry, for example. The die press method may be used. As a binder for this molding,
Organic compounds that do not leave decomposition products when heated, such as paraffin, low molecular weight cellulose derivatives, phenolic resins, etc., may be used alone or dissolved in acetone etc., but they may be used directly without using any of these binders. It may be pressed and molded. In addition, in order to make complex molded products such as tubes and crucibles, it is possible to mold them using a rubber press, but in order to obtain more precise molded products, the raw molded body must be ground before sintering. Alternatively, it is recommended to perform mechanical processing such as slicing. Note that this molding may be performed by the slip cast method, but in this case, a plasticizer such as polyethylene glycol, a low molecular weight cellulose derivative, or paraffin, and a binder such as polyvinyl butyral are added to the silicon carbide powder, and the molding is performed in water. After dispersing the mixture, pour it into a baked plaster mold. Further, a moldable paste made of a mixture of a cellulose derivative or the like and water may be subjected to extrusion molding, injection molding, roll molding, or the like. The molded body thus obtained is then sintered to form a sintered body, but after volatilizing the organic compound added prior to sintering, it is heated under either normal pressure or vacuum. You can do it in this way. If the heating temperature is lower than 1750℃, sintering will be insufficient and the strength of the sintered body will be reduced, and the pore diameter of the resulting porous sintered body will not be constant. This is because the pores of the porous sintered body become obsolete due to the growth of silicon carbide, and coarse pores are generated in some parts due to the sublimation of silicon carbide.
~2500℃, preferably
It is said to be in the range of 1900-2300℃. However, in this sintering process, no sintering aid is added, and the difference in sintering speed between two types of silicon carbide as raw materials is used to create a porous sintered body. , the selection of the heating rate until the sintering temperature of 1750°C is reached is considered to be important. In other words, the rate of temperature increase up to 1000℃ may be relatively fast, for example, 40℃/min, but
Rapid temperature increase above 1200℃ will cause cracks in the target porous sintered body, so the temperature increase rate above 1000℃ is preferably 20℃/min or less.
It is necessary to keep the temperature below 15℃/min. In addition, this sintering must be performed under an inert atmosphere such as nitrogen, argon, helium, etc. or under vacuum, but when cutting the molded product described above prior to this sintering process, This may be calcined if necessary, but this temperature is preferably 1500°C or less, and this temperature may be determined depending on the strength required for machining. In addition, during this sintering, a porous sintered body is obtained by utilizing the difference in sintering speed between ultrafine particle β-type silicon carbide and commercially available fine powder silicon carbide. Therefore, it is not necessary to add a sintering aid, but boron as a sintering aid may be used to increase the sintering density and reduce the pore size.
It may be added in an amount of 0.03 to 1.0 parts by weight. A sintered body having an arbitrary density can be obtained by adding this sintering aid, but the amount of boron added in this case may be the same as the amount described above, and this boron is metal boron. , or a boron compound. In summary, the present invention is a β-type polycrystalline silicon carbide aggregate with crystallites of 50 Å or less and a spherical shape with an average particle size of 0.01 to 1μ, and an ultrafine particle β-type polycrystalline silicon carbide with an average particle size of 6μ. The following relates to a method for producing a porous silicon carbide sintered body by sintering a mixture with finely powdered silicon carbide at 1750 to 2500°C,
Since the material obtained in this way is a porous material, its density is 1.70 to 2.50 g/cc, but since it has a nearly uniform pore size of 0.05 to 100 μ, it can be used with various filters, catalysts, etc. It is said to be useful as a carrier and a support for various thin films. Next, examples of the present invention will be given. Examples 1 to 8 A vertical tubular electric furnace equipped with a mullite furnace tube with an inner diameter of 70 mm and a length of 1500 mm was heated to 1400°C, and hydrogen gas containing 10% by volume of tetramethyldisilane was introduced into it.
When introduced at a rate of 200/hour and reacted for 8 hours,
525 g (yield 85%) of silicon carbide powder was obtained. This is β-SiC (1,1,1) in an electron microscope.
β of less than 50 Å from the measurement results of dark-field images by diffraction.
It is an aggregate of β-type polycrystalline silicon carbide with an average particle size of 0.3 to 1μ and a spherical shape, with an elemental analysis value of 67.1% Si, 31.8% C, and a BET specific surface area. was confirmed to be 18.1 m 2 /g. Next, this ultrafine particulate β-type polycrystalline silicon carbide and commercially available β-type silicon carbide, β-random (trade name, manufactured by IBIDEN Co., Ltd., maximum particle size 6μ) were mixed in the proportions shown in Table 1. The mixture was added to 50 c.c. of hexane solution containing 1% by weight of paraffin, mixed ultrasonically for 15 minutes, and then placed in a 35 mm x 35 mm x 10 mm mold.
Primary molding was performed at 200 kg/cm 2 and secondary molding was performed using a rubber press at a pressure of 1.5 tons/cm 2 . Next, this molded product is placed in a carbon furnace for atmospheric pressure sintering, and the temperature is increased to 40°C until 1000°C under an argon gas atmosphere.
The temperature was raised at a heating rate of 15°C/min from 1000°C to 2100°C, and sintered at 2100°C for 1 hour. The density and oxygen permeation of the obtained sintered body are also listed in Table 1. The results were as expected. Note that in Examples 6 and 7, metal boron was added as a sintering aid, and in this case, it is recognized that it is effective in increasing the density. Also, a reference example is
This was when the heating rate was 40°C/min from 1000°C to the sintering temperature, and there was very little shrinkage, only a slight increase in density, and cracks occurred in the sintered body.
【表】【table】
【表】
商品名、最大粒径５μ）を使用した。
実施例 ９
実施例１におけるテトラメチルジシランをジメ
チルシランとしたほかは同様にしたところ結晶子
が50Å以下のβ型炭化けい素の集合体であり、平
均粒径が0.1〜0.7μである球状形状をもつ、元素
分析値がSi 67.1％、Ｃ 32.3％でBET比表面積
が16.3m2／ｇの超微粒子状β型多結晶炭化けい素
が得られたので、この５重量部に実施例１で使用
した市販の炭化けい素95部とメチルセルロース・
60SH―4000〔信越化学工業(株)製商品名〕５重量
部、グリセリン８重量部、水19重量部を15〜20℃
の温度でヘンシエルミキサーを用いて混合したの
ち、三本ロールを10回パスさせて均一混合物とし
た。
つぎに、この混合物をスクリユー押出機を用い
て巾50mm、厚さ２mmのシートとし、これを50mmの
長さに切断してからラバープレスで1.5t／cm2の加
圧処理し、ついで700℃で30分間加熱して有機質
物を除去後、窒素ガス雰囲気中において1200℃ま
では40℃／分、1200〜2100℃は10℃／分の昇温速
度で昇温させた後、2100℃で１時間焼結したとこ
ろ、密度1.82ｇ／c.c.、酸素透過量2.5×10-2c.c.／
cm．seo.cmHgの多孔質炭化けい素焼結体が得ら
れた。
応用例
実施例２で得た30×30×３mmの多孔質炭化けい
素焼結体を充分に洗滌し乾燥してから、センシタ
イザー液（SnCl2・2H2O ５ｇ／ｌ、HCl 40ml／
）で、ついでアクテイバーター液（２％PdCl
溶液2.5ml／、HCl １ml／）に浸漬して表面
活性処理を行なつた。
つぎにこれを硫酸銅（５水和物）７ｇ／、エ
チレンジアミン４酢酸ナトリウム30ｇ／、
NaOH7ｇ／、ホルマリン（37％）10ml／か
らなる無電解銅メツキ浴に７時間浸漬したとこ
ろ、14μの銅メツキがされた焼結板が得られた
が、このものは接着テープによる剥離テストでも
メツキ膜の剥離は認められず、260℃のハンダ浴
に４分間浸漬してもふくれなどが生じることはな
かつた。
以上の例から、本発明の製造方法で得られた多
孔質炭化けい素焼結体はガス透過率にすぐれてお
り、各種フイルターとして有用とされること（実
施例参照）、またこれはその表面に微小孔がある
ので接着特性にすぐれ、各種コーテイング用基板
としても使用し得ることが確認された（応用例参
照）。[Table] Product name, maximum particle size 5μ) was used.
Example 9 The same procedure as in Example 1 was performed except that dimethylsilane was used instead of tetramethyldisilane. The result was an aggregate of β-type silicon carbide with crystallites of 50 Å or less, and a spherical shape with an average particle size of 0.1 to 0.7 μ. Ultrafine particulate β-type polycrystalline silicon carbide with elemental analysis values of 67.1% Si, 32.3% C, and a BET specific surface area of 16.3 m 2 /g was obtained. 95 parts of commercially available silicon carbide and methylcellulose were used.
60SH-4000 [trade name manufactured by Shin-Etsu Chemical Co., Ltd.] 5 parts by weight, 8 parts by weight of glycerin, and 19 parts by weight of water at 15-20℃
After mixing using a Henschel mixer at a temperature of , the mixture was passed through a triple roll 10 times to obtain a homogeneous mixture. Next, this mixture was made into a sheet with a width of 50 mm and a thickness of 2 mm using a screw extruder, which was cut into 50 mm lengths and then subjected to pressure treatment at 1.5 t/cm 2 using a rubber press, and then heated to 700°C. After heating for 30 minutes to remove organic substances, heat in a nitrogen gas atmosphere at a rate of 40°C/min up to 1200°C, 10°C/min from 1200 to 2100°C, and then heat at 2100°C for 1 hour. After time sintering, the density was 1.82 g/cc, and the oxygen permeation rate was 2.5×10 -2 cc/
cm. A porous silicon carbide sintered body with seo.cmHg was obtained. Application Example After thoroughly washing and drying the porous silicon carbide sintered body of 30 x 30 x 3 mm obtained in Example 2, a sensitizer solution (SnCl 2 2 H 2 O 5 g/l, HCl 40 ml/
), then add activator solution (2% PdCl
Surface activation treatment was performed by immersing the sample in 2.5 ml of solution and 1 ml of HCl. Next, this was mixed with 7 g of copper sulfate (pentahydrate), 30 g of sodium ethylenediaminetetraacetate,
When immersed in an electroless copper plating bath consisting of 7 g of NaOH and 10 ml of formalin (37%) for 7 hours, a sintered plate plated with 14μ copper was obtained, but this plate was not plated even in a peel test using adhesive tape. No peeling of the film was observed, and no blistering occurred even after immersion in a 260°C solder bath for 4 minutes. From the above examples, it can be seen that the porous silicon carbide sintered body obtained by the production method of the present invention has excellent gas permeability and is useful as various filters (see Examples). It was confirmed that it has excellent adhesive properties because of the micropores and can be used as a substrate for various coatings (see application examples).
Claims (1)
であり、平均粒径が0.01〜1μである球状形状の超
微粒子状β型多結晶炭化けい素に、平均粒径が
6μ以下の多結晶炭化けい素微粉末を混合し、成
形体に成形後焼結炉内に装入して1000℃から1750
℃までは20℃／分以下の昇温速度で加熱し、つい
で1750〜2500℃で焼結してなることを特徴とする
多孔質炭化けい素焼結体の製造方法。1. It is an aggregate of β-type silicon carbide with crystallites of 50 Å or less, and has an average particle size of 0.01 to 1μ.
Polycrystalline silicon carbide fine powder of 6μ or less is mixed and formed into a compact, then charged into a sintering furnace and heated from 1000℃ to 1750℃.
A method for producing a porous silicon carbide sintered body, comprising heating at a rate of temperature increase of 20°C/min or less up to 10°C, and then sintering at 1750 to 2500°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59172128A JPS6153163A (en) | 1984-08-18 | 1984-08-18 | Porous silicon carbide sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59172128A JPS6153163A (en) | 1984-08-18 | 1984-08-18 | Porous silicon carbide sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6153163A JPS6153163A (en) | 1986-03-17 |
| JPH0224786B2 true JPH0224786B2 (en) | 1990-05-30 |
Family
ID=15936079
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59172128A Granted JPS6153163A (en) | 1984-08-18 | 1984-08-18 | Porous silicon carbide sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6153163A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2728457B2 (en) * | 1988-10-01 | 1998-03-18 | イビデン株式会社 | Method for producing sintered conductive silicon carbide porous body |
| WO2011064854A1 (en) * | 2009-11-25 | 2011-06-03 | イビデン株式会社 | Process for producing fired ceramic and process for producing honeycomb structure |
| JP5749473B2 (en) * | 2009-11-25 | 2015-07-15 | イビデン株式会社 | Method for manufacturing ceramic fired body and method for manufacturing honeycomb structure |
-
1984
- 1984-08-18 JP JP59172128A patent/JPS6153163A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6153163A (en) | 1986-03-17 |
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