JPS6245344A - Catalyst carrier and its preparation - Google Patents
Catalyst carrier and its preparationInfo
- Publication number
- JPS6245344A JPS6245344A JP60185859A JP18585985A JPS6245344A JP S6245344 A JPS6245344 A JP S6245344A JP 60185859 A JP60185859 A JP 60185859A JP 18585985 A JP18585985 A JP 18585985A JP S6245344 A JPS6245344 A JP S6245344A
- Authority
- JP
- Japan
- Prior art keywords
- silicon carbide
- surface area
- sintered body
- specific surface
- pore volume
- 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.)
- Granted
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 38
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims abstract description 95
- 239000011148 porous material Substances 0.000 claims abstract description 36
- 229910021426 porous silicon Inorganic materials 0.000 claims abstract description 33
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000013078 crystal Substances 0.000 claims abstract description 18
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 9
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 9
- 229910052796 boron Inorganic materials 0.000 claims abstract description 9
- 229910052742 iron Inorganic materials 0.000 claims abstract description 9
- 230000001590 oxidative effect Effects 0.000 claims abstract description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 29
- 238000010304 firing Methods 0.000 claims description 20
- 239000007789 gas Substances 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 14
- 238000000465 moulding Methods 0.000 claims description 13
- 239000000377 silicon dioxide Substances 0.000 claims description 13
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 229910010271 silicon carbide Inorganic materials 0.000 abstract description 43
- 238000005260 corrosion Methods 0.000 abstract description 8
- 230000007797 corrosion Effects 0.000 abstract description 8
- 230000000704 physical effect Effects 0.000 abstract description 2
- 230000006835 compression Effects 0.000 abstract 2
- 238000007906 compression Methods 0.000 abstract 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 20
- 239000002245 particle Substances 0.000 description 16
- 229910052799 carbon Inorganic materials 0.000 description 14
- 239000000463 material Substances 0.000 description 14
- 239000010408 film Substances 0.000 description 12
- 238000002485 combustion reaction Methods 0.000 description 11
- 239000007858 starting material Substances 0.000 description 11
- 230000007423 decrease Effects 0.000 description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 239000000969 carrier Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000011161 development Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000001125 extrusion Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910052786 argon Inorganic materials 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 239000008119 colloidal silica Substances 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 210000003739 neck Anatomy 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- -1 alumina Chemical class 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 238000007084 catalytic combustion reaction Methods 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000004927 clay Substances 0.000 description 2
- 239000011362 coarse particle Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000010419 fine particle Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000001746 injection moulding Methods 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- FHVDTGUDJYJELY-UHFFFAOYSA-N 6-{[2-carboxy-4,5-dihydroxy-6-(phosphanyloxy)oxan-3-yl]oxy}-4,5-dihydroxy-3-phosphanyloxane-2-carboxylic acid Chemical compound O1C(C(O)=O)C(P)C(O)C(O)C1OC1C(C(O)=O)OC(OP)C(O)C1O FHVDTGUDJYJELY-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- 229920002261 Corn starch Polymers 0.000 description 1
- 229920001732 Lignosulfonate Polymers 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 229940072056 alginate Drugs 0.000 description 1
- 229920000615 alginic acid Polymers 0.000 description 1
- 235000010443 alginic acid Nutrition 0.000 description 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000011233 carbonaceous binding agent Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000011280 coal tar Substances 0.000 description 1
- 239000008120 corn starch Substances 0.000 description 1
- 229940099112 cornstarch Drugs 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001493 electron microscopy Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 239000003350 kerosene Substances 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000006193 liquid solution Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229920000609 methyl cellulose Polymers 0.000 description 1
- 239000001923 methylcellulose Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 239000013618 particulate matter Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 239000002296 pyrolytic carbon Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000035939 shock Effects 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
- 239000011863 silicon-based powder Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000004017 vitrification Methods 0.000 description 1
Landscapes
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は高い強度、大きな比表面積と細孔容積を有する
多孔質炭化ケイ素質焼結体からなる触媒担体およびその
製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a catalyst carrier made of a porous silicon carbide sintered body having high strength, large specific surface area and pore volume, and a method for producing the same.
炭化ケイ素は高い硬度、優れた耐摩耗性、優れた耐酸化
性、優れた耐蝕性、良好な熱伝導率、低い熱膨張率、高
い耐熱衝撃性ならびニ高温Ｔ：の高い強度等の化学的お
よび物理的に優れた特性を有し、メカニカルシールや軸
受は等の耐摩耗材料、高温炉用の耐火材、熱交換器、燃
焼管等の耐熱構造材料、酸およびアルカリ等の強い腐蝕
性を有する溶液のポンプ部品等の耐蝕性材料として広く
使用可能な材料である。Silicon carbide has chemical properties such as high hardness, good wear resistance, good oxidation resistance, good corrosion resistance, good thermal conductivity, low coefficient of thermal expansion, high thermal shock resistance and high strength at high temperatures. and have excellent physical properties, such as wear-resistant materials such as mechanical seals and bearings, heat-resistant structural materials such as refractory materials for high-temperature furnaces, heat exchangers, and combustion tubes, and strong corrosive properties such as acids and alkalis. It is a material that can be widely used as a corrosion-resistant material for pump parts for liquid solutions.
一方、これらの性質を有する炭化ケイ素と、その結晶が
形成する通気性を有するところの気孔、すなわち開放気
孔とからなる多孔質炭化ケイ素質焼結体は、前記炭化ケ
イ素の特徴を生かして、高温雰囲気、酸化性雰囲気およ
び／または腐蝕性雰囲気下における耐熱・耐蝕性物質分
離材料として利用可能であり、例えば内燃機関の排気ガ
ス、特にディーゼルエンジンの排気ガス等の高温気体中
に含まれる微粒子カーボン等の微粒子物質の除去のため
に使用されるフィルターとして利用しうろことが考えら
れる。On the other hand, a porous silicon carbide sintered body consisting of silicon carbide having these properties and air-permeable pores formed by its crystals, that is, open pores, takes advantage of the characteristics of silicon carbide and is able to withstand high temperatures. It can be used as a heat-resistant and corrosion-resistant substance separation material in an oxidizing atmosphere and/or a corrosive atmosphere, such as fine particulate carbon contained in high-temperature gases such as internal combustion engine exhaust gas, especially diesel engine exhaust gas. It is conceivable that it could be used as a filter to remove particulate matter.
さらに、この多孔質炭化ケイ素フィルター表面に、酸化
反応用触媒成分を担持せしめた場合には、可燃性のカー
ボン微粒子を燃焼せしめ、ガスに転化させることも可能
で、この場合、この多孔質炭化ケイ素フィルターは、耐
熱・耐蝕触媒としても機能することになる。Furthermore, if a catalyst component for an oxidation reaction is supported on the surface of this porous silicon carbide filter, it is possible to burn the combustible carbon particles and convert them into gas. The filter will also function as a heat-resistant and corrosion-resistant catalyst.
また最近、主として環境汚染防止の観点から、内燃機関
やガスタービン用ボイラーなどの工業用燃焼装置、ある
いは石油ストーブなどの民生用燃焼装置の分野において
、低ＮＯｘ燃焼技術の研究開発が行なわれており、その
一つとして燃焼触媒を用いる触媒燃焼技術が注目を集め
ている。Recently, research and development of low NOx combustion technology has been conducted mainly in the field of industrial combustion equipment such as internal combustion engines and gas turbine boilers, and consumer combustion equipment such as kerosene stoves, mainly from the perspective of preventing environmental pollution. As one such technology, catalytic combustion technology using combustion catalysts is attracting attention.
この触媒燃焼技術の開発における最も重要な要素は、触
媒の開発であり、触媒の開発においては活性な酸化反応
用触媒物質の開発と並んで、活性成分を分散、担持する
ための担体の開発が極めて重要である。The most important element in the development of this catalytic combustion technology is the development of catalysts.In addition to the development of active catalytic materials for oxidation reactions, the development of carriers for dispersing and supporting active components is also important. extremely important.
燃焼触媒用担体においては、触媒表面で進行する燃焼反
応、すなわち、酸化反応を迅速に生起せしめるために表
面積が大きいことに加えて、発生する反応熱をを効に伝
達、除去できるような良好な熱伝導度を有することおよ
び触媒細孔内の物質移動を有効に行なわせるために、ガ
ス等の流体の通過抵抗が小さいこと、すなわち、細孔容
積が大きいこと、さらに、成型体相互のぶつかり合いに
よるアブレイジョン、すなわち磨滅に強いことおよび成
形体自身が十分の機械的強度を有すること、そして、こ
れらの特性が長期間の使用に対して安定していることな
ど、多くの要求を満足することが必要である。In addition to having a large surface area to allow the combustion reaction, that is, the oxidation reaction, to occur quickly on the catalyst surface, the carrier for the combustion catalyst has a good surface area so that the generated reaction heat can be efficiently transferred and removed. In order to ensure thermal conductivity and effective mass transfer within the pores of the catalyst, the passage resistance of fluids such as gas must be small, that is, the pore volume must be large, and the molded bodies must collide with each other. It satisfies many requirements such as being resistant to abrasion caused by abrasion, that the molded product itself has sufficient mechanical strength, and that these properties are stable for long-term use. It is necessary.
このような要件は、燃焼触媒のみならず、一般に反応熱
の発生を伴なう化学反応用の触媒担体、あるいは、高温
で使用される触媒用の担体についても共通的にいえるこ
とである。Such requirements are common not only to combustion catalysts but also to catalyst carriers for chemical reactions that generally involve the generation of reaction heat, or catalyst carriers used at high temperatures.
一方、多孔質炭化ケイ素質焼結体の製造方法としては、
（１）骨材となる炭化ケイ素粒子にガラス質フラックス
、あるいは粘土質などの結合材を加え成形した後、その
成形体を前記結合材が溶融する温度で焼き固めて製造す
る方法、（２）粗大粒の炭化ケイ素粒子と微細な炭化ケ
イ素粒子を混合し成形した後、２０００℃以上の高温で
焼成して製造する方法、あるいは、（３）特開昭４８−
３９５１５号の発明で開示されている炭化ケイ素粉に炭
素粉を加え、または加えずに炭素質ノ＼インダーを加え
ると共に、この炭素粉及び焼成時に生成されるバインダ
ーからの遊離炭素と反応する理論量のケイ素質粉を添加
して形成し、しかる後、この成形体の炭素粉中で１９０
０〜２４００°Ｃに加熱して成形体中の炭素分をケイ素
化することを特徴とする均質多孔性再結晶炭化ケイ素体
の製造方法等が従来知られている。On the other hand, as a method for producing a porous silicon carbide sintered body,
(1) A method of manufacturing by adding a binder such as vitreous flux or clay to silicon carbide particles serving as an aggregate, molding it, and then baking and hardening the molded product at a temperature at which the binder melts; (2) A method of mixing coarse silicon carbide particles and fine silicon carbide particles, molding the mixture, and then firing the mixture at a high temperature of 2000°C or higher, or (3) JP-A-1978-
In addition to adding a carbonaceous binder to the silicon carbide powder disclosed in the invention of No. 39515 with or without addition of carbon powder, the theoretical amount that reacts with the carbon powder and free carbon from the binder produced during firing. 190% silicon powder is added to form the molded body, and then 190%
A method for producing a homogeneous porous recrystallized silicon carbide body is conventionally known, which is characterized by heating to 0 to 2400°C to siliconize the carbon content in the molded body.
しかしながら、上記（１）項のごとき結合材としてガラ
ス質フラックス、あるいは粘土を加え製造した多孔質体
の強度は、結合材が１０００〜１４００°Ｃで溶融する
ため、多孔質体はこの温度域、特にガラス化転移温度付
近で変形し、著しく強度が低下するだけでなく、耐薬品
性、耐酸化性が要求される分野における使用がかぎられ
るという欠点がある。However, the strength of porous bodies manufactured by adding glassy flux or clay as a binder as described in item (1) above is limited to 1000 to 1400°C, since the binder melts at 1000 to 1400°C. In particular, it deforms near the vitrification transition temperature, resulting in a significant decrease in strength, and has the disadvantage that its use is limited in fields where chemical resistance and oxidation resistance are required.
一方、上記（２）項及び（３）項の方法で製造された多
孔質体の構造をモデル的に図示すれば、図面に示すごと
き構造のものであり、多孔質炭化ケイ素骨材１とその骨
材を被覆して、骨材同志を結合する炭化ケイ素質結合材
あるいは炭素質結合材２および間隙３とから構成される
。On the other hand, if the structure of the porous body manufactured by the methods of (2) and (3) above is illustrated as a model, it has the structure as shown in the drawing, and it is composed of porous silicon carbide aggregate 1 and its structure. It is composed of a silicon carbide binding material or a carbonaceous binding material 2 that covers the aggregate and binds the aggregates together, and a gap 3.
前記多孔質体の間隙３、すなわち開放気孔は殆んど成形
時に骨材粒子の配置によって決定され、多孔質体の細孔
容積は高々０．２ｍｌ／ｇである。The voids 3, or open pores, of the porous body are determined mostly by the arrangement of aggregate particles during molding, and the pore volume of the porous body is at most 0.2 ml/g.
また、多孔質体中の細孔容積を大きくしようとすると、
骨材粒子となる粗大粒子を多く必要とし、その結果骨材
粒子の接触点が少なくなり、多孔質体の強度は著しく低
下し、しがも比表面積は０．５ ｍ ／ ｇ以下で著し
く小さいものになる。Also, when trying to increase the pore volume in a porous body,
It requires a large number of coarse particles that become aggregate particles, and as a result, the number of contact points between aggregate particles is reduced, the strength of the porous body is significantly reduced, and the specific surface area is extremely small at 0.5 m / g or less. Become something.
一方、強度の高い多孔質体とするためには骨材の粒度配
合を粗粒と中程度の粒子および／または微粒子と適度に
混合し形成することが必要であり、その結果、多孔質体
の細孔容積は高々０．１ｍｌ／ｇで著しく小さく、極端
な場合、一部の開放気孔が閉塞してしまう傾向がある。On the other hand, in order to form a porous body with high strength, it is necessary to mix the particle size of the aggregate appropriately with coarse particles, medium particles, and/or fine particles. The pore volume is extremely small, at most 0.1 ml/g, and in extreme cases there is a tendency for some open pores to become blocked.
このため、このような多孔質体を流体が通過する際の抵
抗は著しく高くなり、物質分離用フィルターや、触媒担
体等として利用する場合、著しく不利益となる。For this reason, the resistance when a fluid passes through such a porous body becomes extremely high, which is extremely disadvantageous when used as a substance separation filter, a catalyst carrier, or the like.
したがって、触媒担体として好適な特性を有する炭化ケ
イ素質焼結体、すなわち、取扱いに容易な強度を有し、
しかも細孔容積が０．２％／ｇより大きく、比表面積が
３％／ｇよりも大きな多孔質炭化ケイ素質焼結体は存在
しないのが現状である。Therefore, the silicon carbide sintered body has characteristics suitable as a catalyst carrier, that is, it has strength that is easy to handle,
Moreover, at present, there is no porous silicon carbide sintered body with a pore volume larger than 0.2%/g and a specific surface area larger than 3%/g.
そこで本発明者らは、前記従来の技術の欠点を解消し、
かつ改善して、耐熱触媒担体として必要な特性を有する
多孔質炭化ケイ素質焼結体からなる触媒担体を供給する
ことを目的として種々研究を重ねた結果、比表面積が大
きく、特定の不純物成分の少ない炭化ケイ素粉末を出発
原料とし、特定の雰囲気および温度範囲内で焼結するこ
とによって、比表面積および細孔容積の減少を抑え、し
かも高い強度ををする多孔質炭化ケイ素質焼結体を製造
する方法およびその多孔質炭化ケイ素質焼結体の表面に
酸化物被膜を形成させることにより、触媒担体として利
用する場合に必要な比表面積が太き（しかも活性な表面
を有する酸化物被覆多孔質炭化ケイ素質焼結体を製造す
る方法を発明するに至った。本発明は上述のごとき多孔
質炭化ケイ素質焼結体からなる触媒担体及びその製造方
法を提供することを目的としたものである。Therefore, the present inventors solved the drawbacks of the conventional technology,
As a result of various research aimed at providing a catalyst carrier made of a porous silicon carbide sintered body that has the characteristics necessary as a heat-resistant catalyst carrier, the results show that it has a large specific surface area and is free from certain impurity components. By using a small amount of silicon carbide powder as a starting material and sintering it within a specific atmosphere and temperature range, we produce a porous silicon carbide sintered body that suppresses the decrease in specific surface area and pore volume and has high strength. By forming an oxide film on the surface of the porous silicon carbide sintered body, the specific surface area required for use as a catalyst support is large (and the oxide-coated porous material has an active surface). A method for manufacturing a silicon carbide sintered body has been invented.The object of the present invention is to provide a catalyst carrier made of the above-mentioned porous silicon carbide sintered body and a method for manufacturing the same. .
［発明の構成］
すなわち、本発明の触媒担体は、主として炭化ケイ素よ
りなる結晶が三次元の網目構造をなし、開放気孔を有す
る多孔質炭化ケイ素質焼結体であって、細孔容積が０．
２〜２．０ｍｌ／ｇの範囲にあり、比表面積が３ ｍ
／ ｇ以上で、かつ平均圧縮強度が３００ｋｇｆ ／
ｃｆ以上の多孔質炭化ケイ素質焼結体であることを特徴
としたものであり、また、上記の多孔質炭化ケイ素質焼
結体の表面が、シリカ膜または／およびアルミナ膜によ
って被覆されており、その比表面積が１０ｉ／ｇ以上で
あることも有効な特徴であり、更に、その製造方法は、
（１）比表面積が３ｍ／ｇ以上で、ホウ素、アルミニウ
ムおよび鉄の含有量の合計が元素に換算して０．３重量
％以下である炭化ケイ素粉末を所望の形状に成形する工
程、（２）前記（１）の工程により得られた成形体を耐
熱性の容器に装入して、１４００℃〜２０００°Ｃの温
度範囲内において、少なくとも１０分間ＣＯあるいはＮ
２の少なくともいづれかのガス分圧が１００ Ｐａ以上
に維持された非酸化性雰囲気中で焼成する工程、（３）
前記成形体を１６００°Ｃ〜２０００°Ｃの最高温度で
焼成する工程のシーケンスから構成される。[Structure of the Invention] That is, the catalyst carrier of the present invention is a porous silicon carbide sintered body in which crystals mainly made of silicon carbide form a three-dimensional network structure and have open pores, and the pore volume is 0. ．．
It is in the range of 2 to 2.0 ml/g and has a specific surface area of 3 m
/ g or more, and the average compressive strength is 300 kgf /
cf or more, the porous silicon carbide sintered body is characterized in that the surface of the porous silicon carbide sintered body is covered with a silica film or/and an alumina film. , its specific surface area of 10 i/g or more is also an effective feature, and its manufacturing method is
(1) A step of molding silicon carbide powder having a specific surface area of 3 m/g or more and a total content of boron, aluminum, and iron of 0.3% by weight or less in terms of elements into a desired shape, (2 ) The molded product obtained in step (1) above is charged into a heat-resistant container and heated with CO or N for at least 10 minutes within a temperature range of 1400°C to 2000°C.
(3) firing in a non-oxidizing atmosphere in which the partial pressure of at least one of the gases in step 2 is maintained at 100 Pa or higher;
It consists of a sequence of steps in which the molded body is fired at a maximum temperature of 1600°C to 2000°C.
以下本発明の詳細な説明するが、まず、本発明の触媒担
体は、主として炭化ケイ素よりなる結晶が三次元の網目
構造をなし、開放気孔を有する多孔質炭化ケイ素質焼結
体であって、その細孔容積が０．２〜２．０ｍｌ／ｇの
範囲であることが必要である。The present invention will be described in detail below. First, the catalyst carrier of the present invention is a porous silicon carbide sintered body in which crystals mainly composed of silicon carbide have a three-dimensional network structure and have open pores, It is necessary that the pore volume is in the range of 0.2 to 2.0 ml/g.
ここで、細孔容積は置換法により求めた値であり、その
理由は、前記多孔質体の細孔容積が０．２ｍｌ／ｇより
小さいと、細孔内での物質移動が阻害され、触媒担体と
して利用する場合不利であり、また２、０ｍｌ／ｇより
大きいと、多孔質化炭化ケイ素質焼結体の強度が低下し
、実用上の取り扱いが困難となるためである。なかでも
０．３〜１．５ ｍｌ／ ｇの細孔容積であることが触
媒担体として良好な結果を期待することができる。Here, the pore volume is a value determined by the substitution method, and the reason is that when the pore volume of the porous body is smaller than 0.2 ml/g, mass transfer within the pores is inhibited, and the catalyst This is disadvantageous when used as a carrier, and if it exceeds 2.0 ml/g, the strength of the porous silicon carbide sintered body decreases, making practical handling difficult. Among these, good results can be expected as a catalyst carrier if the pore volume is 0.3 to 1.5 ml/g.
また、本発明の炭化ケイ素質焼結体の比表面積は、少な
くとも３ｍ／ｇであることが必要であり、その理由は比
表面積が３ ｎ（／ ｇよりも小さいと、触媒担体等と
しては実用に耐えないためである。なお、前記比表面積
は窒素吸着によるＢＥＴ法によって求められる値である
。Further, the specific surface area of the silicon carbide sintered body of the present invention must be at least 3 m/g, and the reason is that if the specific surface area is smaller than 3 n(/g), it cannot be used as a catalyst carrier, etc. This is because the specific surface area is a value determined by the BET method using nitrogen adsorption.
さらに本発明の炭化ケイ素質焼結体の平均圧縮強度は少
なくとも３００ｋｇｆ／ｃｉであることが必要である。Further, it is necessary that the average compressive strength of the silicon carbide sintered body of the present invention is at least 300 kgf/ci.
その理由は平均圧縮強度が３００ｋｇｆ／ｄよりも小さ
いと、実用上の取り扱いが困難となるからであり、なか
でも、前記炭化ケイ素質焼結体の平均圧縮強度は５００
ｋｇｆ／ｃｏ！以上であることが、種々の形状を持った
触媒担体として使用する上でより有利である。The reason for this is that if the average compressive strength is less than 300 kgf/d, practical handling becomes difficult.
kgf/co! The above is more advantageous for use as a catalyst carrier having various shapes.
次に、本発明の多孔質炭化ケイ素質焼結体からなる触媒
担体の製造方法について詳細に説明する。Next, a method for producing a catalyst carrier made of a porous silicon carbide sintered body according to the present invention will be explained in detail.
本発明の製造方法は下記（１）、（２）および（３）の
各工程のシーケンスからなるものである。The manufacturing method of the present invention consists of the following sequence of steps (1), (2), and (3).
（１） 比表面積が３ｍ／ｇ以上で、ホウ素。(1) Boron with a specific surface area of 3 m/g or more.
アルミニウムおよび鉄の含有量の合計が元素に換算して
０．３重量％以下である炭化ケイ素粉末を所望の形状に
成形する工程。A step of molding silicon carbide powder into a desired shape in which the total content of aluminum and iron is 0.3% by weight or less in terms of elements.
（２）上記（１）の工程により得られた成形体を耐熱性
の容器に装入して、１４００°Ｃ〜２０００’ｃの温度
範囲内において、少なくとも１０分間ＣＯあるいはＮ２
の少なくともいづれかのガス分圧が１００ Ｐａ以上に
維持された非酸化性雰囲気中で焼成する工程。(2) Place the molded product obtained in step (1) above into a heat-resistant container and store it in a temperature range of 1400°C to 2000'c for at least 10 minutes using CO or N2.
A step of firing in a non-oxidizing atmosphere in which the partial pressure of at least one of the gases is maintained at 100 Pa or more.
（３）前記成形体を１６００°Ｃ〜２０００℃の最高温
度で焼成する工程。(3) A step of firing the molded body at a maximum temperature of 1600°C to 2000°C.
以上の三工程によって細孔容積が０．２〜２．０ｍｌ／
ｇ、比表面積が３ｍ／ｇ以上、そして平均圧縮強度が３
００ｋｇｆ ／ ｃｔＡ以上である多孔質炭化ケイ素質
焼結体からなる触媒担体を製造することができる。Through the above three steps, the pore volume is reduced to 0.2-2.0ml/
g, specific surface area of 3 m/g or more, and average compressive strength of 3
It is possible to produce a catalyst carrier made of a porous silicon carbide sintered body having a power density of 00 kgf/ctA or more.
本発明によれば、前記出発原料は、少なくとも３ ｍ
／ ｇの比表面積を有する炭化ケイ素粉末であることが
必要であり、この理由は比表面積が３ ｍ ／ ｇより
小さい出発原料を用いた成形体は、焼結の後、比表面積
を増加させることが困難であり、少なくとも３ ｍ ／
ｇの比表面積を有する炭化ケイ素質焼結体を得ること
が困難となるからである。According to the invention, said starting material is at least 3 m
It is necessary that the silicon carbide powder has a specific surface area of 3 m / g, and the reason for this is that molded bodies using starting materials with a specific surface area smaller than 3 m / g have a specific surface area that increases after sintering. is difficult and at least 3 m/
This is because it becomes difficult to obtain a silicon carbide sintered body having a specific surface area of g.
また、出発原料として使用される炭化ケイ素は、α型、
β型および／または非晶質炭化ケイ素のいづれも使用す
ることができるが、なかでも大きな比表面積をもつ微粒
子を安価に、しがち容易に製造できるβ型炭化ケイ素を
より効果的に使用することができる。In addition, silicon carbide used as a starting material is α-type,
Both β-type and/or amorphous silicon carbide can be used, but β-type silicon carbide can be used more effectively because it can easily produce fine particles with a large specific surface area at low cost. I can do it.
また、本発明によれば、出発原料に含まれる炭化ケイ素
粉末１００重量％に対し、ホウ素、アルミニウムおよび
鉄の含有量の合計が元素に換算して０．３重量％以下で
あることが必要である。Further, according to the present invention, it is necessary that the total content of boron, aluminum, and iron is 0.3% by weight or less in terms of elements, based on 100% by weight of silicon carbide powder contained in the starting material. be.
その理由は、前記ホウ素、アルミニウムおよび鉄の含有
量の合計が元素に換算して０．３重量％より多いと、炭
化ケイ素粉末中に含有されている遊離炭素との相互作用
によって焼結時に焼成収縮し易く、細孔容積が減少し、
本発明の目的とする０、２ｍｌ／ｇ以上の細孔容積を有
する炭化ケイ素質焼結体を得ることが困難になるからで
ある。The reason for this is that if the total content of boron, aluminum and iron is more than 0.3% by weight in terms of elements, sintering occurs due to interaction with free carbon contained in silicon carbide powder. Easily shrinks, pore volume decreases,
This is because it becomes difficult to obtain a silicon carbide sintered body having a pore volume of 0.2 ml/g or more, which is the object of the present invention.
なお、上記炭化ケイ素粉末に５重量％以下の遊離炭素を
含有させるべく炭素質物質を添加することができる。Note that a carbonaceous substance may be added to the silicon carbide powder so that it contains 5% by weight or less of free carbon.
上記遊離炭素は結晶粒の粗大化を抑制する作用を有して
おり、出発原料中に存在させることにより、炭化ケイ素
結晶粒径を均一化し、比表面積の減少を抑制することが
できる上、比較的高強度の焼結体を得ることができる。The above-mentioned free carbon has the effect of suppressing the coarsening of crystal grains, and by making it present in the starting raw material, it is possible to make the silicon carbide crystal grain size uniform, suppress the decrease in specific surface area, and compare A sintered body with high strength can be obtained.
また、上記遊離炭素の含有量を５重量％以下とする理由
は、５重量％よりも多いと炭化ケイ素粉末粒子間に過剰
の炭素が存在することになリ、粒と粒との結合を著しく
阻害するため、焼結体の強度が劣化するからである。Furthermore, the reason why the free carbon content is set to 5% by weight or less is that if it is more than 5% by weight, excessive carbon will exist between the silicon carbide powder particles, which will significantly impair the bond between the particles. This is because the strength of the sintered body deteriorates due to the interference.
北記炭素物質としては、焼結開始時に炭素を存在させら
れるものであればよく、例えばフェノール樹脂、リグニ
ンスルホン酸塩、ポリビニルアルコール、コンスターチ
、ｔｉｎ、コールタールピンチ、アルギン酸塩のような
各種有機物質、あるいはカーボンブラック、アセチレン
ブラックのような熱分解炭素を有利に使用することがで
きる。The carbon material mentioned above may be any material as long as it allows carbon to be present at the start of sintering, such as various organic materials such as phenol resin, lignin sulfonate, polyvinyl alcohol, cornstarch, tin, coal tar pinch, and alginate. Alternatively, pyrolytic carbon such as carbon black or acetylene black can be advantageously used.
本発明においては、前記成形体中に占める炭化ケイ素質
は生成形体１００容量％に対し、１０〜６０容量％であ
ることが好ましく、その理由は成形体中の炭化ケイ素質
が１０容量％よりも少ないと、前記炭化ケイ素質焼結体
の強度が低下するからであり、６０容量％より大きいと
、前記炭化ケイ素質焼結体の細孔容積が０．２ ｍｌ／
ｇ以下となるためであり、なかでも１７〜５５容量％
であることがより好ましい結果を与える。In the present invention, it is preferable that the silicon carbide content in the molded body is 10 to 60 volume% based on 100 volume% of the formed body. If it is less than 60% by volume, the pore volume of the silicon carbide sintered body will be reduced to 0.2 ml/
g or less, especially 17 to 55% by volume.
gives more favorable results.
本発明によれば、前記出発原料を所望される形状に成形
する方法としては、セラミック業界において一般に使用
されている従来形式の成形法、例えばグイプレス成形、
射出成形、押出成形あるいは鋳込み成形等のいづれでも
適用可能であるが、量産性に冨み、しかも生成形体の気
孔率を容易に、しかも任意に変えることのできるダイプ
レス成形、射出成形、押出成形をより有利に適用できる
。According to the present invention, the method for forming the starting material into the desired shape includes conventional forming methods commonly used in the ceramic industry, such as Gouipress molding.
Any method such as injection molding, extrusion molding, or cast molding can be applied, but die press molding, injection molding, and extrusion molding are suitable for mass production and can easily and arbitrarily change the porosity of the formed body. It can be applied more advantageously.
そして、前記成形体中に占める炭化ケイ素質を１０〜６
０容量％とすべ（、成形圧力および成形助剤の添加量を
任意に選択することができる。The silicon carbide content in the molded body is 10 to 6.
The molding pressure and the amount of molding aid added can be arbitrarily selected.
例えば、炭素ケイ素質の含まれる割合を小さくするには
、成形圧を比較的小さくし、成形助剤の量を多くする方
法を適用することができる。For example, in order to reduce the proportion of carbon-silicon substances contained, a method can be applied in which the molding pressure is relatively low and the amount of molding aid is increased.
また、本発明によれば、前記生成形体は１４００℃〜２
０００℃の温度範囲内において少なくとも１０分間雰囲
気中のＣＯあるいはＮ２の少なくともいずれかのガス分
圧が１００ Ｐａ以上に維持された非酸化性雰囲気中で
焼成されることが必要であり、その理由は上記温度雰囲
気内において少なくとも１０分間雰囲気中のＣＯあるい
はＮ２の少なくトモいづれかのガス分圧を１００ Ｐａ
以上とすることによって、ネックの成長を促進させ、か
つ炭化ケイ素の焼結時における焼成収縮を効果的に抑制
することができ、その結果、炭化ケイ素の結晶同志の接
合強度が高くなり、高い強度を有する焼結体を得ること
ができ、しかも大きな細孔容積を得ることができるから
であり、なかでも少なくとも３０分間上記の雰囲気中で
焼成されることがより好ましい。Further, according to the present invention, the formed body is heated at a temperature of 1400°C to 2°C.
It is necessary to perform firing in a non-oxidizing atmosphere in which the partial pressure of at least one of CO or N2 in the atmosphere is maintained at 100 Pa or higher within a temperature range of 000°C for at least 10 minutes. The partial pressure of either CO or N2 gas in the atmosphere at the above temperature was increased to 100 Pa for at least 10 minutes.
By doing so, it is possible to promote neck growth and effectively suppress firing shrinkage during sintering of silicon carbide.As a result, the bonding strength between silicon carbide crystals is increased, resulting in high strength. This is because it is possible to obtain a sintered body having a large pore volume and a large pore volume, and it is particularly preferable to perform firing in the above atmosphere for at least 30 minutes.
また、本発明によれば、上記成形体を焼成雰囲気を制御
することのできる耐熱性容器内に装入し、焼成すること
が有利である。Further, according to the present invention, it is advantageous to charge the molded body into a heat-resistant container in which the firing atmosphere can be controlled and to fire the molded body.
このように耐熱性の容器内に装入して焼成雰囲気を制御
しつつ焼成することが有利である理由は、隣接する炭化
ケイ素の結晶同志の結合およびネックの成長を促進させ
ることができるからである。The reason why it is advantageous to charge the material into a heat-resistant container and fire it while controlling the firing atmosphere is because it can promote the bonding of adjacent silicon carbide crystals and the growth of necks. be.
前述のごとく、耐熱性の容器内に生成形体を装入して焼
成雰囲気を制御しつつ焼成することによって隣接する炭
化ケイ素結晶同志の結合およびネックの成長を促進させ
ることができる理由は、炭化ケイ素粒子間における炭化
ケイ素の蒸発−再凝縮および／または表面拡散による移
動を促進することができるためと考えられ、強度の高い
炭化ケイ素質焼結体を得ることができる。As mentioned above, the reason why bonding between adjacent silicon carbide crystals and neck growth can be promoted by charging the formed body into a heat-resistant container and firing while controlling the firing atmosphere is that silicon carbide This is thought to be because the movement of silicon carbide between particles by evaporation-recondensation and/or surface diffusion can be promoted, and a silicon carbide sintered body with high strength can be obtained.
上記耐熱性の容器としては、黒鉛や炭化ケイ素などの材
質およびこれらと同等の機能を有するものを有利に使用
することができる。As the heat-resistant container, materials such as graphite and silicon carbide, and materials having functions equivalent to these materials can be advantageously used.
また、上記生成形体を焼成雰囲気を制御することのでき
る耐熱性容器中に装入して焼成することにより、焼成時
における炭化ケイ素の揮散率を５重量％以下に制御する
ことが有利である。Further, it is advantageous to control the volatilization rate of silicon carbide to 5% by weight or less during firing by charging the formed body into a heat-resistant container in which the firing atmosphere can be controlled and firing it.
更に、本発明によれば、上記の成形体を１６００℃〜２
０００℃の範囲の最高温度で焼成することが必要であり
、その理由は、焼成温度が１６００℃よりも低いと粒子
の成長が不十分であり、高い強度を有する焼結体を得る
ことが困難であり、２０００℃よりも高い温度になると
、炭化ケイ素の粒成長が非常に活発となり、粒子が粗大
化するため、比表面積が著しく減少し、しかも分解が盛
んになり、発達した炭化ケイ素結晶が逆にやせ細ってし
まい、その結果、高い強度を持った焼結体を得ることが
困難となるためであり、なかでも１７００℃〜１９５０
℃の間で焼成することが好適である。Furthermore, according to the present invention, the above molded body is heated at 1600°C to 2°C.
It is necessary to fire at a maximum temperature in the range of 1,600°C, because if the firing temperature is lower than 1,600°C, grain growth will be insufficient and it will be difficult to obtain a sintered body with high strength. When the temperature is higher than 2000℃, the grain growth of silicon carbide becomes very active and the particles become coarser, resulting in a significant decrease in the specific surface area and moreover, the decomposition becomes active and the developed silicon carbide crystals become On the contrary, it becomes thin and thin, and as a result, it becomes difficult to obtain a sintered body with high strength.
It is preferable to calcinate between .degree.
上記の方法によって製造された多孔質炭化ケイ素質焼結
体は、耐熱、耐蝕性にすくれ、かつアルミナや窒化ケイ
素等の酸化物、窒化物系セラミックス多孔体に比べ２〜
４倍程度、ステンレス鋼５５８Ｃとほぼ同程度の良好な
熱伝導率を有している。The porous silicon carbide sintered body produced by the above method has excellent heat resistance and corrosion resistance, and is 2 to 2 times more resistant than oxide and nitride ceramic porous bodies such as alumina and silicon nitride.
It has good thermal conductivity, which is about 4 times as good as stainless steel 558C.
これらの特性は、燃焼触媒など高温条件下で使用され、
かつ反応熱のすみやかな伝達及び除去を必要とする触媒
の担体として使用した場合に効果的である。These properties are used under high temperature conditions such as combustion catalysts,
Moreover, it is effective when used as a carrier for a catalyst that requires rapid transfer and removal of reaction heat.
適当な形状に成形された炭化ケイ素質焼結体は、それ自
体で触媒担体として使用できるほか、この炭化ケイ素質
焼結体の表面をシリカあるいは／およびアルミナ等の活
性酸化物の薄膜で被覆することにより、触媒成分を担持
分散させるに当って好適な表面活性と、その焼結体の表
面積よりもさらに大きな表面積を付与することもできる
。The silicon carbide sintered body formed into an appropriate shape can be used as a catalyst support by itself, or the surface of the silicon carbide sintered body can be coated with a thin film of active oxide such as silica and/or alumina. By doing so, it is possible to impart suitable surface activity for carrying and dispersing catalyst components and a surface area even larger than that of the sintered body.
炭化ケイ素質焼結体の表面に酸化物被膜を形成する場合
、シリカ（ＳｉＯ□）被膜単独の被覆のほか、シリカ被
膜上にさらにアルミナ（Ａｌ２Ｏ２）等の酸化物被膜を
形成させ、シリカ／アルミナ等の複合酸化物被膜を形成
させる方法が、活性表面と大表面積を得るには好適であ
る。When forming an oxide film on the surface of a silicon carbide sintered body, in addition to coating with a silica (SiO□) film alone, an oxide film such as alumina (Al2O2) is further formed on the silica film. A method of forming a composite oxide film such as the above is suitable for obtaining an active surface and a large surface area.
この場合、シリカ被膜は基体である炭化ケイ素質焼結体
と化学的に強い結合を作るのできわめて安定性がよい。In this case, the silica coating forms a strong chemical bond with the silicon carbide sintered body that is the base, so it is extremely stable.
このようにして形成されたシリカ被膜はそれ自身アルミ
ナ、チタニア（ＴｉＯ□）ジルコニア（ＺｒＯ□）など
の他の金属酸化物に対して強い親和性をもつので、この
シリカ被膜上にさらにこれら別種の金属酸化物被膜を形
成させることができる。The silica film formed in this way itself has a strong affinity for other metal oxides such as alumina, titania (TiO□), and zirconia (ZrO□). A metal oxide film can be formed.
このようにして製造された酸化物被膜の多孔質炭化ケイ
素質焼結体は、表面は触媒担体として好適なシリカ、ア
ルミナ、チタニアなどと同等の特性を有し、同時にバル
ク特性としては、耐熱、耐蝕、良熱伝導性の炭化ケイ素
の性質をもつことができ、上記触媒担体としてきわめて
有効な素材となる。The oxide-coated porous silicon carbide sintered body produced in this way has surface properties equivalent to those of silica, alumina, titania, etc., which are suitable as catalyst carriers, and at the same time has bulk properties such as heat resistance, It has the properties of silicon carbide, which is corrosion resistant and has good thermal conductivity, making it an extremely effective material as the catalyst carrier.
次に、本発明を、本発明の各実施例およびその比較例に
ついて説明すると、まず、本発明の実施例１の出発原料
として使用した炭化ケイ素粉末は、９４．６重量％がβ
型結晶で残部が実質的に２ Ｈ型結晶よりなり、０．２
９重量％の遊離炭素、０．１７重量％の酸素、０．０３
重量％の鉄、０．０３重量％のアルミニウムを主として
含有し、ホウ素は検出されなかった。Next, the present invention will be explained with respect to each example of the present invention and its comparative example. First, the silicon carbide powder used as the starting material in Example 1 of the present invention has a β content of 94.6% by weight.
type crystal, the remainder essentially consists of 2H type crystal, and 0.2
9 wt% free carbon, 0.17 wt% oxygen, 0.03
It mainly contained 0.03% by weight of iron, 0.03% by weight of aluminum, and no boron was detected.
また、この原料粉末は０．２８μｍの平均粒径を有して
おり、その比表面積は１８．７ｍ／ｇであった。Further, this raw material powder had an average particle size of 0.28 μm and a specific surface area of 18.7 m/g.
上記炭化ケイ素粉末１００重量％に対し、ポリビニルア
ルコール５重量％、水３００重量％ヲ配合し、ボールミ
ルの中で５時間混合した後乾燥した。5% by weight of polyvinyl alcohol and 300% by weight of water were blended with 100% by weight of the above silicon carbide powder, mixed in a ball mill for 5 hours, and then dried.
この乾燥混合物を適量採取して、顆粒化した後金属製押
し型を用いて５０ ｋｇ ／ ｃｌの圧力で成形した結
果、この生成形体のうち炭化ケイ素の占める割合は全体
の４２．９容量％であった。An appropriate amount of this dry mixture was collected, granulated, and then molded using a metal mold at a pressure of 50 kg/cl. As a result, the proportion of silicon carbide in the formed product was 42.9% by volume of the total. there were.
上記の生成形体を耐熱性の容器である黒鉛製ルツボに装
入し、タンマン型焼成炉を使用して１気圧の主としてア
ルゴンガス雰囲気中で焼成した。The above-mentioned formed body was placed in a graphite crucible, which is a heat-resistant container, and fired in a Tamman-type firing furnace in an atmosphere of mainly argon gas at 1 atm.
昇温過程は４５０°Ｃ／時間で１４００℃まで昇温し、
１４００″Ｃから１６００°Ｃまでの間を１５０°Ｃ／
時間で昇温し、ＣＯ淵度を１００ Ｐａ以下にした。In the heating process, the temperature was raised to 1400°C at 450°C/hour.
150°C/between 1400″C and 1600°C
The temperature was raised over time to bring the CO depth to 100 Pa or less.
その後、最高温度１９００℃まで３００”Ｃ／時間の割
合で昇温し、最高温度で４時間保持した。Thereafter, the temperature was increased to a maximum temperature of 1900° C. at a rate of 300”C/hour, and maintained at the maximum temperature for 4 hours.
なお、１５００°Ｃから１９００°Ｃまでの温度範囲内
でｃ ｏ 濃度が２０分間３００±５０ Ｐａの範囲内
になるようにアルゴンガス流量を適宜調整した。Note that the argon gas flow rate was appropriately adjusted so that the co concentration was within the range of 300±50 Pa for 20 minutes within the temperature range of 1500°C to 1900°C.
得られた焼結体の密度は１．３６ｇ／ｃｎ！であり、細
孔容積は０．４２ｍ１／ｇ、比表面積は１７．９ｍ／ｇ
であり、この焼結体の平均圧縮強度は１２２０ｋｇｆ／
ｃｔの高い値を有していた。The density of the obtained sintered body was 1.36g/cn! The pore volume is 0.42 m/g and the specific surface area is 17.9 m/g.
The average compressive strength of this sintered body is 1220 kgf/
It had a high value of CT.
次に、上記実施例１に対比させるための比較例１にて、
その出発原料として使用した炭化ケイ素粉末は、９２．
８重量％がβ型結晶で残部が実質的に２ Ｈ型結晶より
なり、０．２１重量％の遊離炭素、０．１７重量％の酸
素、０．０５重量％の鉄、０．１重量％のアルミニウム
、０．４重量％のホウ素を主として含有し、０．２７μ
ｍの平均粒径を有する炭化ケイ素粉末であり、その比表
面積はｔ６．ｓ＝／ｇであった。Next, in Comparative Example 1 for comparison with Example 1 above,
The silicon carbide powder used as the starting material was 92.
8% by weight of β-type crystals and the remainder substantially of 2H-type crystals, 0.21% by weight of free carbon, 0.17% by weight of oxygen, 0.05% by weight of iron, 0.1% by weight. of aluminum, mainly containing 0.4% boron, and 0.27μ
It is a silicon carbide powder having an average particle size of m, and a specific surface area of t6. s=/g.
この出発原料を用いて、実施例１と同様の方法で炭化ケ
イ素質焼結体を得たところ、焼結体の密度は１．９７ｇ
／ｃｕｔであり、細孔容積は０．１９ｍ１／ｇであり、
比表面積は１．８ｍ／ｇと著しく低いものであった。Using this starting material, a silicon carbide sintered body was obtained in the same manner as in Example 1, and the density of the sintered body was 1.97 g.
/cut, the pore volume is 0.19 m1/g,
The specific surface area was extremely low at 1.8 m/g.
次に、本発明の実施例２の出発原料として使用した炭化
ケイ素粉末は、９６．３重量％がβ型結晶であり、残部
が実質的に２Ｈ型結晶よりなり、０．８１重量％の遊離
炭素、０．１）重量％の酸素、０．０１）重量のアルミ
ニウムを主として含有し、鉄およびホウ素は検出されな
い原料粉末であった。Next, the silicon carbide powder used as the starting material in Example 2 of the present invention has 96.3% by weight of β-type crystals, the remainder substantially consists of 2H-type crystals, and 0.81% by weight of free The raw powder contained mainly carbon, 0.1% by weight of oxygen, and 0.01% by weight of aluminum, with no iron or boron detected.
また、この粉末の平均粒径は０．１５μｍであり、比表
面積は５１．２ｒｒｊ／ｇであった。Moreover, the average particle diameter of this powder was 0.15 μm, and the specific surface area was 51.2 rrj/g.
この出発原料１００重量％に対し、比表面積１２８１７
ｇのカーボンブランク粉末２重量％、ポリオキシエチレ
ンノニルフェニルエーテル０．４重量％、水２０重量％
およびメチルセルロース粉末２００重量％を添加し、ニ
ーダ−によって加圧混練した後、押し出し圧力２０ｋｇ
ｒ／ｃＪで押出成形を行い、径５鶴、長さ５龍のペレッ
トを成形した。Based on 100% by weight of this starting material, the specific surface area is 12817
g carbon blank powder 2% by weight, polyoxyethylene nonylphenyl ether 0.4% by weight, water 20% by weight
After adding 200% by weight of methylcellulose powder and kneading under pressure with a kneader, extrusion pressure was 20kg.
Extrusion molding was carried out at r/cJ to form pellets with a diameter of 5 mm and a length of 5 mm.
この成形体の炭化ケイ素の占める割合は、２５．３容量
％であった。The proportion of silicon carbide in this molded body was 25.3% by volume.
上記の成形体を２℃／時間で３００℃まで脱脂を行った
後、黒鉛製ルツボに装入し、タンマン炉を使用して１気
圧の主としてアルゴンガス雰囲気中で焼成した。After degreasing the above molded body to 300° C. at 2° C./hour, it was placed in a graphite crucible and fired in a Tammann furnace at 1 atmosphere, mainly in an argon gas atmosphere.
その昇温過程は１４００°Ｃまで２５０°Ｃ／時間で昇
温し、１４００℃から１５００℃までの間を６０°Ｃ／
時間で界温し、ＣＯ濃度を１００ Ｐａ以下にした。The temperature rise process is to raise the temperature at 250°C/hour up to 1400°C, and then to increase the temperature at 60°C/hour between 1400°C and 1500°C.
The mixture was brought to ambient temperature for an hour to reduce the CO concentration to 100 Pa or less.
その後、最高温度１７５０°Ｃまで９００℃／時間で昇
温し、１７５０°Ｃで１０分間保持したが、１５００”
ｃ以降の焼成過程中の雰囲気はすべてＮ２濃度が５００
±１００ ＰａになるようにＮ２ガスを適宜注入した。After that, the temperature was raised at a rate of 900°C/hour to a maximum temperature of 1750°C and held at 1750°C for 10 minutes.
The atmosphere during the firing process from c onwards has a N2 concentration of 500.
N2 gas was appropriately injected so that the pressure was ±100 Pa.
得られた焼結体の密度は０．７７ｇ／ｃＡであり、細孔
容積は０．９９ｍ１／ｇ、比表面積は３８．１ｍ／ｇで
あり、この焼結体の平均圧縮強度は５５０ｋｇｆ ／ｃ
ｍｌの高い値を有していた。The density of the obtained sintered body was 0.77 g/cA, the pore volume was 0.99 m1/g, the specific surface area was 38.1 m/g, and the average compressive strength of this sintered body was 550 kgf/c.
It had a high value of ml.
さらに、本発明の実施例３として、例えば国産のコロイ
ダルシリカ（スノーテックス２０．固形分？農度約２０
％）を蒸留水で２倍に希釈し、ＰＨ＝１０に調整した。Furthermore, as Example 3 of the present invention, for example, domestically produced colloidal silica (Snowtex 20. Solid content? Agricultural degree approximately 20
%) was diluted twice with distilled water and adjusted to pH=10.
一方、実施例１において得られた多孔質炭化ケイ素質焼
結体（比表面積１７．９ｍ／ｇ）を真空容器中に装入し
、１）０−２ＮＨで脱ガス処理した後、上記コロイダル
シリカ溶液を同容器内に注入し、しかる後、大気圧まで
パージした。On the other hand, the porous silicon carbide sintered body (specific surface area 17.9 m/g) obtained in Example 1 was charged into a vacuum container, and after 1) degassing treatment with 0-2NH, the colloidal silica The solution was poured into the same container and then purged to atmospheric pressure.
パージ後、焼結体をコロイダルシリカ溶液から取出し、
乾燥皿中１００″Ｃで乾燥した後、シリコニット炉に装
入し、１４００°Ｃで、５０重量％水薄気−空気混合ガ
ス５β／分流通下で５時間保持し焼成した。After purging, remove the sintered body from the colloidal silica solution,
After drying at 100''C in a drying dish, it was placed in a silicone furnace and fired at 1400°C for 5 hours under a flow of 5β/min of 50 wt % water thin air-air mixed gas.
得られたシリカ被覆の多孔質炭化ケイ素質焼結体の重量
増加は１３．５％であり、、比表面積は１６．８ｍ／ｇ
であった。The weight increase of the obtained silica-coated porous silicon carbide sintered body was 13.5%, and the specific surface area was 16.8 m/g.
Met.
電子顕微鏡観察により、炭化ケイ素表面に、０．３μｍ
の厚さでシリカ被膜が形成されていることが確かめられ
た。By electron microscopy observation, 0.3μm of silicon carbide surface was observed.
It was confirmed that a silica film was formed with a thickness of .
また、本発明の実施例４として、例えば国産のアルミナ
ゾル（アルミナゾル−１０００，固形分濃度１０％）に
蒸留水を加え、ＰＨ＝４に調整した。Further, as Example 4 of the present invention, for example, distilled water was added to domestically produced alumina sol (Alumina Sol-1000, solid content concentration 10%) to adjust the pH to 4.
一方、実施例３で得られたシリカ被膜の多孔質炭化ケイ
素質焼結体（比表面積１６．．８％／ｇ）を、上記アル
ミナゾルに実施例３と同様の方法で真空含浸し、アルミ
ナゾルから取出した後、乾燥気中で５０℃で乾燥した。On the other hand, the silica-coated porous silicon carbide sintered body (specific surface area 16.8%/g) obtained in Example 3 was vacuum impregnated into the alumina sol in the same manner as in Example 3. After taking it out, it was dried at 50° C. in dry air.
その乾燥体をエレマ炉中に装入し、空気中５００℃で２
時間保持して焼成した。。The dried product was charged into an Elema furnace and heated at 500℃ in air for 2 hours.
It was held for a while and fired. .
得られたシリカ／アルミナ複合酸化物被覆の多孔質炭化
ケイ素質焼結体の重量増加は８．２％、比表面積は５２
．５ｍ／ｇであった。The weight increase of the obtained porous silicon carbide sintered body coated with silica/alumina composite oxide was 8.2%, and the specific surface area was 52.
．． It was 5m/g.
そこで、電子顕微鏡観察により、シリカ被覆多孔質炭化
ケイ素質焼結体の表面に、０．１５μｍの厚さでアルミ
ナ被覆が形成されていることが確かめられた。Accordingly, by electron microscopic observation, it was confirmed that an alumina coating with a thickness of 0.15 μm was formed on the surface of the silica-coated porous silicon carbide sintered body.
従って、本発明では、耐熱、耐蝕性で、かつ良熱伝導性
の耐熱触媒として必要な特性を有する多孔質炭化ケイ素
質焼結体を供給でき、しかも、その多孔質炭化ケイ素質
焼結体の比表面積および細孔容積の減少を抑えると共に
、その多孔質炭化ケイ素質焼結体に高い強度をもたせ得
るので、その取扱が容易になるという効果がある。Therefore, in the present invention, it is possible to provide a porous silicon carbide sintered body having properties necessary as a heat-resistant catalyst that is heat resistant, corrosion resistant, and has good thermal conductivity. This has the effect of suppressing a decrease in specific surface area and pore volume, and also imparting high strength to the porous silicon carbide sintered body, making it easier to handle.
さらに、本発明では、上記多孔質炭化ケイ素質焼結体の
表面に酸化物被膜を形成させることにより、耐熱触媒担
体として利用する場合に必要な大比表面積活性表面を有
する酸化物被覆付きの多孔質炭化ケイ素質焼結体を容易
に提供できる。Furthermore, in the present invention, by forming an oxide film on the surface of the porous silicon carbide sintered body, the porous silicon carbide sintered body has an oxide-coated porous structure having a large specific surface area and an active surface necessary for use as a heat-resistant catalyst carrier. A quality silicon carbide sintered body can be easily provided.
図面は多孔質体の構造をモデル的に図示した拡大図であ
る。
工業技術院長の復代理人
イビデン株式会社の代理人The drawing is an enlarged view illustrating the structure of a porous body as a model. Sub-agent of the Director of the Agency of Industrial Science and Technology; Agent of IBIDEN Co., Ltd.
Claims (1)
造をなし、開放気孔を有する多孔質炭化ケイ素質焼結体
であって、細孔容積が０．２〜２．０ｍｌ／ｇの範囲に
あり、比表面積が３ｍ＾２／ｇ以上で、かつ平均圧縮強
度が３００ｋｇｆ／ｃｍ＾２以上の多孔質炭化ケイ素質
焼結体であることを特徴とする触媒担体。 ２、前記多孔質炭化ケイ素質焼結体の表面はシリカ膜ま
たは／およびアルミナ膜によって被覆されており、その
比表面積が１０ｍ＾２／ｇ以上である特許請求の範囲第
１項記載の触媒担体。 ３、細孔容積が０．２〜２．０ｍｌ／ｇの範囲にあり、
比表面積が３ｍ＾２／ｇ以上で、かつ平均圧縮強度が少
なくとも３００ｋｇｆ／ｃｍ＾２である多孔質炭化ケイ
素質焼結体からなる触媒担体の製造方法であって、（１
）比表面積が３ｍ＾２／ｇ以上で、ホウ素、アルミニウ
ムおよび鉄の含有量の合計が元素に換算して０．３重量
％以下である炭化ケイ素粉末を所望の形状に成形する工
程、（２）前記（１）の工程により得られた成形体を耐
熱性の容器内に装入して、１４００℃〜２０００℃の温
度範囲内において少なくとも１０分間、ＣＯあるいはＮ
＿２の少なくともいずれかのガス分圧が１００Ｐａ以上
に維持された非酸化性雰囲気中で焼成する工程、（３）
前記成形体を１６００℃〜２０００℃の最高温度で焼成
する工程のシーケンスからなる多孔質炭化ケイ素質焼結
体からなる触媒担体の製造方法。[Scope of Claims] 1. A porous silicon carbide sintered body in which crystals mainly composed of silicon carbide form a three-dimensional network structure and have open pores, the pore volume being 0.2 to 2.0 ml. /g, a specific surface area of 3 m^2/g or more, and an average compressive strength of 300 kgf/cm^2 or more. 2. The catalyst carrier according to claim 1, wherein the surface of the porous silicon carbide sintered body is coated with a silica film or/and an alumina film, and the specific surface area thereof is 10 m^2/g or more. . 3. Pore volume is in the range of 0.2 to 2.0 ml/g,
A method for producing a catalyst carrier made of a porous silicon carbide sintered body having a specific surface area of 3 m^2/g or more and an average compressive strength of at least 300 kgf/cm^2, the method comprising:
) A step of molding silicon carbide powder into a desired shape with a specific surface area of 3 m^2/g or more and a total content of boron, aluminum, and iron of 0.3% by weight or less in terms of elements, (2 ) The molded product obtained in step (1) above is charged into a heat-resistant container, and heated with CO or N for at least 10 minutes within a temperature range of 1400°C to 2000°C.
(3) a step of firing in a non-oxidizing atmosphere in which the partial pressure of at least one of the gases in _2 is maintained at 100 Pa or more;
A method for producing a catalyst carrier made of a porous silicon carbide sintered body, comprising a sequence of steps of firing the molded body at a maximum temperature of 1600°C to 2000°C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60185859A JPH0624636B2 (en) | 1985-08-26 | 1985-08-26 | Catalyst carrier and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60185859A JPH0624636B2 (en) | 1985-08-26 | 1985-08-26 | Catalyst carrier and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6245344A true JPS6245344A (en) | 1987-02-27 |
| JPH0624636B2 JPH0624636B2 (en) | 1994-04-06 |
Family
ID=16178127
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60185859A Expired - Lifetime JPH0624636B2 (en) | 1985-08-26 | 1985-08-26 | Catalyst carrier and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0624636B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02180641A (en) * | 1988-12-29 | 1990-07-13 | Ibiden Co Ltd | Catalyst carrier and its manufacture |
| JP2001510729A (en) * | 1997-07-25 | 2001-08-07 | ペシネイ ルシェルシュ | Silicon carbide foam with large specific surface area and improved mechanical properties |
| JP2010201362A (en) * | 2009-03-04 | 2010-09-16 | National Institute Of Advanced Industrial Science & Technology | Catalyst support, method for producing the catalyst support, and catalyst |
| JP2012101215A (en) * | 2010-10-13 | 2012-05-31 | Ibiden Co Ltd | Honeycomb catalyst body and method of manufacturing the same |
| KR101379476B1 (en) * | 2007-04-24 | 2014-04-02 | 주식회사 칸세라 | METHOD FOR MANUFACTURING SiC HONEYCOMB STRUCTURE |
| JP2019518706A (en) * | 2016-04-28 | 2019-07-04 | インディアン・インスティテゥート・オブ・テクノロジー | Method for converting sulfur trioxide and method for producing hydrogen |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4642955B2 (en) * | 1999-06-23 | 2011-03-02 | イビデン株式会社 | Catalyst support and method for producing the same |
| EP1808228A4 (en) * | 2004-09-02 | 2008-02-13 | Ibiden Co Ltd | Honeycomb structure, method for production thereof and exhaust gas purification device |
| US11772082B1 (en) * | 2018-06-21 | 2023-10-03 | Avn Corporation | Catalyst supports—composition and process of manufacture |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5026795A (en) * | 1973-07-12 | 1975-03-19 | ||
| JPS5053290A (en) * | 1973-09-13 | 1975-05-12 | ||
| JPS624446A (en) * | 1985-06-29 | 1987-01-10 | Ibiden Co Ltd | Catalyst carrier |
-
1985
- 1985-08-26 JP JP60185859A patent/JPH0624636B2/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5026795A (en) * | 1973-07-12 | 1975-03-19 | ||
| JPS5053290A (en) * | 1973-09-13 | 1975-05-12 | ||
| JPS624446A (en) * | 1985-06-29 | 1987-01-10 | Ibiden Co Ltd | Catalyst carrier |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02180641A (en) * | 1988-12-29 | 1990-07-13 | Ibiden Co Ltd | Catalyst carrier and its manufacture |
| JP2001510729A (en) * | 1997-07-25 | 2001-08-07 | ペシネイ ルシェルシュ | Silicon carbide foam with large specific surface area and improved mechanical properties |
| KR101379476B1 (en) * | 2007-04-24 | 2014-04-02 | 주식회사 칸세라 | METHOD FOR MANUFACTURING SiC HONEYCOMB STRUCTURE |
| JP2010201362A (en) * | 2009-03-04 | 2010-09-16 | National Institute Of Advanced Industrial Science & Technology | Catalyst support, method for producing the catalyst support, and catalyst |
| JP2012101215A (en) * | 2010-10-13 | 2012-05-31 | Ibiden Co Ltd | Honeycomb catalyst body and method of manufacturing the same |
| JP2019518706A (en) * | 2016-04-28 | 2019-07-04 | インディアン・インスティテゥート・オブ・テクノロジー | Method for converting sulfur trioxide and method for producing hydrogen |
| US11390522B2 (en) | 2016-04-28 | 2022-07-19 | Indian Institute Of Technology, Delhi | Process for conversion of sulfur trioxide and hydrogen production |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0624636B2 (en) | 1994-04-06 |
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