JPH0624636B2 - Catalyst carrier and method for producing the same - Google Patents
Catalyst carrier and method for producing the sameInfo
- Publication number
- JPH0624636B2 JPH0624636B2 JP60185859A JP18585985A JPH0624636B2 JP H0624636 B2 JPH0624636 B2 JP H0624636B2 JP 60185859 A JP60185859 A JP 60185859A JP 18585985 A JP18585985 A JP 18585985A JP H0624636 B2 JPH0624636 B2 JP H0624636B2
- Authority
- JP
- Japan
- Prior art keywords
- silicon carbide
- sintered body
- surface area
- specific surface
- catalyst carrier
- 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
- 239000003054 catalyst Substances 0.000 title claims description 39
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 89
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 46
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 42
- 239000011148 porous material Substances 0.000 claims description 32
- 229910021426 porous silicon Inorganic materials 0.000 claims description 29
- 238000010304 firing Methods 0.000 claims description 22
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 21
- 239000000377 silicon dioxide Substances 0.000 claims description 21
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 16
- 239000013078 crystal Substances 0.000 claims description 16
- 238000000576 coating method Methods 0.000 claims description 13
- 238000000465 moulding Methods 0.000 claims description 13
- 239000011248 coating agent Substances 0.000 claims description 12
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 8
- 229910052782 aluminium Inorganic materials 0.000 claims description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 8
- 229910052796 boron Inorganic materials 0.000 claims description 8
- 229910052742 iron Inorganic materials 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 239000007888 film coating Substances 0.000 claims 1
- 238000009501 film coating Methods 0.000 claims 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 20
- 239000010408 film Substances 0.000 description 17
- 229910052799 carbon Inorganic materials 0.000 description 14
- 239000007789 gas Substances 0.000 description 14
- 239000002245 particle Substances 0.000 description 14
- 239000007858 starting material Substances 0.000 description 12
- 238000002485 combustion reaction Methods 0.000 description 11
- 238000000034 method Methods 0.000 description 11
- 239000000463 material Substances 0.000 description 10
- 238000005260 corrosion Methods 0.000 description 8
- 230000007797 corrosion Effects 0.000 description 8
- 239000000843 powder Substances 0.000 description 8
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 238000011161 development Methods 0.000 description 5
- 238000007254 oxidation reaction Methods 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000012546 transfer Methods 0.000 description 5
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000011362 coarse particle Substances 0.000 description 4
- 238000001125 extrusion Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- 239000008119 colloidal silica Substances 0.000 description 3
- -1 combustion tubes Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000010419 fine particle Substances 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 239000000243 solution Substances 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
- 239000006229 carbon black Substances 0.000 description 2
- 239000011233 carbonaceous binding agent Substances 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 238000007084 catalytic combustion reaction Methods 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 239000004927 clay Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000004907 flux Effects 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
- 238000002156 mixing Methods 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000007787 solid 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
- 229910018072 Al 2 O 3 Inorganic materials 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
- 229910010413 TiO 2 Inorganic materials 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
- 239000004480 active ingredient Substances 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
- 239000003575 carbonaceous material Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000011294 coal tar pitch Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000008120 corn starch Substances 0.000 description 1
- 229910021419 crystalline silicon Inorganic materials 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 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
- 238000004898 kneading Methods 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
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000013618 particulate matter Substances 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000003825 pressing Methods 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
- 238000012827 research and development Methods 0.000 description 1
- 102200094897 rs121913558 Human genes 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 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
- 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
- 239000000758 substrate Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Landscapes
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
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。TECHNICAL FIELD The present invention relates to a catalyst carrier composed of a porous silicon carbide sintered body having high strength, a large specific surface area and a 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に高温で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
け等の耐摩耗材料、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 high hardness, good wear resistance, good oxidation resistance, good corrosion resistance, good thermal conductivity, low coefficient of thermal expansion, high thermal shock resistance, and chemical and physical properties such as high strength at high temperature. Has excellent properties, and wear resistant materials such as mechanical seals and bearings, refractory materials for high temperature furnaces, heat exchangers, heat resistant structural materials such as combustion tubes, and solutions with 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 and the like.
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ることが考えら
れる。On the other hand, a silicon carbide having these properties, and a porous silicon carbide-based sintered body consisting of pores having air permeability formed by the crystal, that is, open pores, is a high temperature by utilizing the characteristics of the silicon carbide. It can be used as a heat-resistant / corrosion-resistant material separation material in an atmosphere, an oxidizing atmosphere, and / or a corrosive atmosphere, and is, for example, particulate carbon contained in the exhaust gas of an internal combustion engine, especially in a high-temperature gas such as the exhaust gas of a diesel engine. It is conceivable that it can be used as a filter used for removal of the 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、可熱性のカー
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, when a catalyst component for oxidation reaction is supported on the surface of this porous silicon carbide filter, it is also possible to burn heatable carbon fine particles and convert it into gas. In this case, this porous silicon carbide filter is used. The filter will also function as a heat 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, mainly from the viewpoint of preventing environmental pollution, research and development of low NOx combustion technology has been carried out in the field of industrial combustion devices such as boilers for internal combustion engines and gas turbines, or consumer combustion devices such as oil stoves. As one of them, catalytic combustion technology using a combustion catalyst has been 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 factor in the development of this catalytic combustion technology is the development of the catalyst.In the development of the catalyst, along with the development of the catalytic material for the active oxidation reaction, the development of the carrier for dispersing and supporting the active ingredient is required. 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、発生する反応熱を有効に伝
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
型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 the case of a carrier for combustion catalyst, in addition to having a large surface area to promptly generate a combustion reaction that progresses on the catalyst surface, that is, an oxidation reaction, good heat that can effectively transfer and remove the generated reaction heat is used. In order to have conductivity and to effectively carry out mass transfer in the catalyst pores, the passage resistance of a fluid such as gas is small, that is, the pore volume is large, and moreover, due to collisions between the molded bodies. Satisfaction of many requirements such as abrasion, that is, abrasion resistance and that the molded body itself has sufficient mechanical strength, and that these properties are stable for long-term use. 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 commonly applicable not only to combustion catalysts but also to catalyst carriers for chemical reactions that generally generate heat of reaction, or carriers for catalysts 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)粗大粒の炭化ケイ粗粒子と微細な炭化ケイ粗
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
加えずに炭素質バ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ハ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1900〜2400℃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) Vitreous flux on silicon carbide particles as an aggregate,
Alternatively, after molding by adding a binder such as clay, a method of producing the molded product by baking at a temperature at which the binder melts, (2) coarse silicon carbide coarse particles and fine silicon carbide coarse particles. After mixing and molding, a method of producing by firing at a high temperature of 2000 ° C. or higher, or (3) adding or not adding carbon powder to the silicon carbide powder disclosed in the invention of JP-A-48-39515 A carbonaceous binder is added to the carbon powder, and a theoretical amount of siliconaceous powder that reacts with the free carbon from the hinder generated during firing is added to form the carbonaceous powder. Conventionally known is a method for producing a homogeneously porous crystalline silicon carbide body, which comprises heating 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℃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 the porous body produced by adding glassy flux or clay as the binder as in the above item (1), the binder melts at 1000 to 1400 ° C. It deforms near the glass transition temperature,
Not only is the strength remarkably reduced, but it has the drawback that it can only be used in fields requiring chemical resistance and oxidation resistance.
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 produced by the methods of the above (2) and (3) is schematically illustrated, it has a structure as shown in the drawing, and the porous silicon carbide aggregate 1 and its It is composed of a silicon carbide-based binder or carbonaceous binder 2 and a gap 3 which cover the aggregate and bond the aggregates together.
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 gaps 3, that is, open pores, of the porous body are almost determined by the arrangement of the aggregate particles at the time of 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、しかも比表面積は０．５m2／ｇ以下で著しく小さ
いものになる。Also, when trying to increase the pore volume in the porous body,
A large amount of coarse particles, which are aggregate particles, are required. As a result, the number of contact points of the aggregate particles is reduced, the strength of the porous body is significantly reduced, and the specific surface area is 0.5 m 2 / g or less, which is extremely small. Become.
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 obtain a porous body having high strength, it is necessary to form a mixture of the particle size of the aggregate by appropriately mixing coarse particles and medium particles and / or fine particles, and as a result, The pore volume is as small as 0.1 ml / g at most, and in an extreme case, some open pores tend to be closed.
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。Therefore, the resistance when a fluid passes through such a porous material 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０．２m2／ｇより大きく、比表面積が
３m2／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, a silicon carbide sintered body having suitable properties as a catalyst carrier, that is, having a strength that is easy to handle,
Moreover, at present, there is no porous silicon carbide sintered body having a pore volume of more than 0.2 m 2 / g and a specific surface area of more than 3 m 2 / 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
かも高い強度を有する多孔質炭化ケイ素質焼結体を生成
させ、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大きく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からなる触媒担体
を製造する方法を発明するに至った。本発明は上述のご
とき酸化物被覆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 have solved the drawbacks of the conventional techniques described above,
As a result of various studies aimed at supplying a catalyst carrier composed of a porous silicon carbide-based sintered body having properties required as a heat-resistant catalyst carrier by improvement, a large specific surface area and By using a small amount of silicon carbide powder as a starting material and sintering in a specific atmosphere and temperature range, it is possible to suppress the reduction of the specific surface area and the pore volume and to generate a porous silicon carbide sintered body having high strength. By forming an oxide film on the surface of the porous silicon carbide sintered body, an oxide-coated porous silicon carbide sintered body having a large specific surface area required for use as a catalyst carrier and having an active surface The inventors have invented a method for producing a catalyst carrier composed of an aggregate. It is an object of the present invention to provide a catalyst carrier composed of the oxide-coated porous silicon carbide sintered body as described above and a method for producing the same.
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
し、細孔容積が０．２〜２．０ml／ｇの範囲にあり、比
表面積が３m2／ｇ以上で、かつ平均圧縮強度が300kgf／
cm2以上の多孔質炭化ケイ素質焼結体の多孔質炭化ケイ
素質焼結体の表面に、シリカ膜または／およびアルミナ
膜の被覆を有しており、その比表面積が10m2／ｇ以上で
あることを特徴とし、更に、その製造方法は、(1)比表
面積が３m2／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℃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、(3)前記成形体を1600℃〜2000℃の最高温度で
焼成する工程の、および(4)生成する焼結体にシリカ膜
または／およびアルミナ膜を被覆する工程、シーケンス
から構成される。That is, in the catalyst carrier of the present invention, crystals mainly composed of silicon carbide form a three-dimensional network structure, have open pores, have a pore volume in the range of 0.2 to 2.0 ml / g, and have a specific surface area. Is 3 m 2 / g or more, and the average compressive strength is 300 kgf /
The surface of the porous silicon carbide sintered body of the porous silicon carbide sintered body of cm 2 or more has a coating of a silica film and / or an alumina film, and its specific surface area is 10 m 2 / g or more. Furthermore, the production method is (1) the specific surface area is 3 m 2 / g or more, and the total content of boron, aluminum and iron is 0.3% by weight or less in terms of elements. Step of molding the silicon carbide powder into a desired shape, (2) charging the molded body obtained by the step (1) into a heat-resistant container, in the temperature range of 1400 ℃ ~ 2000 ℃, at least Step of firing for 10 minutes in a non-oxidizing atmosphere in which at least one of CO and N 2 gas partial pressure is maintained at 100 Pa or more, (3) Step of firing the molded body at a maximum temperature of 1600 ° C to 2000 ° C And (4) coating the resulting sintered body with a silica film and / or an alumina film. The sequence consists of sequences.
以下本発明の詳細を説明するが、まず、本発明の触媒担
体のベース物質は、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。Hereinafter, the details of the present invention will be described. First, the base material of the catalyst carrier of the present invention is a porous silicon carbide-based sintered body having open pores in which crystals mainly composed of silicon carbide form a three-dimensional network structure. And the pore volume is 0.2-2.
It should be in the range of 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、多孔質体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．
３〜１．５ml／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 obtained by the substitution method, because the reason is that when the pore volume of the porous body is smaller than 0.2 ml / g, the mass transfer in the pores is inhibited and the catalyst This is because it is disadvantageous when it is used as a carrier, and when it is larger than 2.0 ml / g, the strength of the porous silicon carbide-based sintered body is lowered and it becomes difficult to handle in practical use. Above all, 0.
A pore volume of 3 to 1.5 ml / g can be expected to give good results as a catalyst carrier.
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３m2／ｇであることが必要であり、その理由は比
表面積が３m2／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-based sintered body of the present invention is required to be at least 3 m 2 / g, and the reason is that when the specific surface area is smaller than 3 m 2 / g, it is practically used as a catalyst carrier or the like. This is because they cannot withstand. The specific surface area is a value obtained 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／cm2であることが必要である。その理
由は平均圧縮強度が300kgf／cm2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500kgf／cm2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。Furthermore, the average compressive strength of the silicon carbide sintered body of the present invention must be at least 300 kgf / cm 2 . The reason is that if the average compressive strength is less than 300 kgf / cm 2 , it is difficult to handle in practical use. Above all, the average compressive strength of the silicon carbide sintered body is 500 kgf / cm 2 or more. Is more advantageous for use as a catalyst carrier having various shapes.
次に、本発明の被覆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, the method for producing the catalyst carrier comprising the coated porous silicon carbide-based sintered body of the present invention will be described 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 production method of the present invention comprises a sequence of steps (1), (2) and (3) below.
(1) 比表面積が３m2／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。(1) A step of forming a silicon carbide powder having 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 into a desired shape.
(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℃〜2000℃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) charging the molded body obtained by the step (1) into a heat-resistant container, within a temperature range of 1400 ° C to 2000 ° C,
Step of firing in a non-oxidizing atmosphere in which the partial pressure of at least either CO or N 2 is maintained at 100 Pa or more for at least 10 minutes.
(3) 前記成形体1600℃〜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.
(4)生成する焼結体にシリカ膜または／およびアルミナ
膜を被覆する工程。(4) A step of coating the produced sintered body with a silica film and / or an alumina film.
まず上記三工程によって細孔容積が０．２〜２．０ml／
ｇ、比表面積が３m2／ｇ以上、そして平均圧縮強度が30
0kgf／cm2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。First, the pore volume is 0.2-2.0 ml /
g, specific surface area of 3 m 2 / g or more, and average compressive strength of 30
It is possible to produce a catalyst carrier composed of a porous silicon carbide-based sintered body having a pressure of 0 kgf / cm 2 or more.
本発明によれば、前記出発原料は、少なくとも３m2／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３m2／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３m2／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 2 / g
It is necessary to use a silicon carbide powder having a specific surface area of 1. The reason for this is that it is difficult to increase the specific surface area of a compact using a starting material having a specific surface area of less than 3 m 2 / g after sintering. This is because it is difficult to obtain a silicon carbide based sintered body having a specific surface area of at least 3 m 2 / 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、しかも容易に製造できるβ型炭化ケイ素を
より効果的に使用することができる。Further, silicon carbide used as a starting material is α type,
Either β-type and / or amorphous silicon carbide can be used, and among them, β-type silicon carbide that can easily produce fine particles having a large specific surface area at low cost can be used more effectively. it can.
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 with respect to 100% by weight of silicon carbide powder contained in the starting material. is there.
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 is that if the total content of boron, aluminum and iron is more than 0.3% by weight in terms of elements, it shrinks during sintering due to the interaction with the free carbon contained in the silicon carbide powder. This is because it is easy to do so, the pore volume decreases, and it becomes difficult to obtain the silicon carbide sintered body having the 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。A carbonaceous substance may be added to the silicon carbide powder so as to contain 5% by weight or less of free carbon.
上記遊離炭素は結晶粉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 free carbon has an effect of suppressing coarsening of the crystal powder, and by being present in the starting material, the silicon carbide crystal grain size can be made uniform, and the reduction of the specific surface area can be suppressed, and comparison is made. It is possible to obtain a sintered body with extremely high strength.
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り、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。In addition, the reason for setting the content of the above free carbon to 5% by weight or less is that if it is more than 5% by weight, excess carbon exists between the silicon carbide powder particles, and the binding between the particles is significantly hindered. Therefore, the strength of the sintered body deteriorates.
上記炭化物質としては、焼結開始時に炭素を存在させら
れるものであればよく、例えばフエノール樹脂、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、糖類、コールタールピッチ、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 carbonized substance may be any one that allows carbon to be present at the start of sintering, for example, phenol resin, lignin sulfonate, polyvinyl alcohol, corn starch, sugar, coal tar pitch, various organic substances such as 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
は生成形態 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０．２ml／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, the content of silicon carbide in the molded body is preferably 10 to 60% by volume, based on 100% by volume of the produced form, because the silicon carbide in the molded body is more than 10% by volume. This is because if the amount is small, the strength of the silicon carbide based sintered body is lowered, and if it is more than 60% by volume, the pore volume of the silicon carbide based sintered body becomes 0.2 ml / g or less, Above all, 17 to 55% by volume gives more preferable 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、例えばダイプレス成形、
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、量産性に富み、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, as a method of forming the starting material into a desired shape, a conventional type molding method generally used in the ceramic industry, for example, die press molding,
Although it can be applied to any of injection molding, extrusion molding, casting molding, etc., die press molding, injection molding, and extrusion molding, which have high mass productivity and can easily and arbitrarily change the porosity of the formed body, are more suitable. It can be applied to advantage.
そして、前記成形体中に占める炭化ケイ素質を10〜60容
量％とすべく、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 molding pressure and the amount of the molding aid added can be arbitrarily selected so that the content of silicon carbide in the molded body is 10 to 60% by volume.
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 silicon carbide contained, a method of making the molding pressure relatively small and increasing the amount of the molding aid can be applied.
また、本発明によれば、前記成形形体は1400℃〜2000℃
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の少なくともいづれか
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 molded form has a temperature of 1400 ° C to 2000 ° C.
It is necessary to perform firing in a non-oxidizing atmosphere in which the gas partial pressure of at least one of CO and N 2 in the atmosphere is maintained at 100 Pa or more for at least 10 minutes within the temperature range of the above. By increasing the gas partial pressure of at least either CO or N 2 to 100 Pa or more in the temperature atmosphere for at least 10 minutes, the neck growth is promoted and the firing shrinkage during sintering of silicon carbide is effective. This is because, as a result, the bonding strength between the crystals of silicon carbide is increased, a sintered body having high strength can be obtained, and a large pore volume can be obtained. However, it is more preferable that the firing is performed 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 load the molded body in a heat-resistant container capable of controlling a firing atmosphere and fire it.
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 load the heat-resistant container in a heat-resistant container to control the firing atmosphere and to promote the bonding between adjacent silicon carbide crystals and the growth of the neck can be promoted. .
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 described above, the reason why it is possible to promote the bonding of adjacent silicon carbide crystal grains and the growth of the neck by charging the green body into a heat resistant container and firing while controlling the firing atmosphere. It is considered that this is because the evaporation-recondensation of silicon carbide between particles and / or the transfer due to surface diffusion can be promoted, and a silicon carbide-based sintered body having 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
質の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 those having a function equivalent to these 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 at the time of firing to 5% by weight or less by charging the green compact into a heat-resistant container capable of controlling the firing atmosphere and firing.
更に、本発明によれば、上記の成形体を1600℃〜2000℃
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-mentioned molded body is 1600 ° C to 2000 ° C.
It is necessary to fire at the maximum temperature in the range of 1, because the firing temperature is lower than 1600 ℃, the growth of particles is insufficient, it is difficult to obtain a sintered body having high strength , When the temperature is higher than 2000 ° C, the grain growth of silicon carbide becomes very active and the particles become coarse, so that the specific surface area decreases remarkably, and the decomposition becomes active, and the developed silicon carbide crystal is reversed. I'm thin and as a result,
This is because it becomes difficult to obtain a sintered body having high strength, and it is particularly preferable to perform firing at 1700 ° C to 1950 ° C.
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、耐蝕性にすぐれ、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S58Cとほぼ同程度の良好な熱伝
導率を有している。The porous silicon carbide-based sintered body produced by the above method has excellent heat resistance and corrosion resistance, and is 2 to more than oxide or nitride ceramics porous body such as alumina or silicon nitride.
It has a good thermal conductivity about four times that of stainless steel S58C.
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 characteristics are used under high temperature conditions such as combustion catalysts,
In addition, it is effective when used as a carrier for a catalyst that requires prompt transfer and removal of reaction heat.
このようにして得られた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ができる。By coating the surface of the silicon carbide-based sintered body thus obtained with a thin film of an active oxide such as silica and / or alumina, a surface activity suitable for supporting and dispersing a catalyst component and its A surface area larger than the surface area of the sintered body can be provided.
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（SiO2）被膜単独の被覆のほか、シリカ被膜
上にさらにアルミナ（Al2O3）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 the silicon carbide sintered body, in addition to the silica (SiO 2 ) film alone, an oxide film such as alumina (Al 2 O 3 ) is further formed on the silica film, A method of forming a composite oxide film such as silica / alumina 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 film has a chemically strong bond with the silicon carbide sintered body as the substrate, and therefore has extremely good stability.
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（TiO2）ジルコニア（ZrO2）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 coating formed in this way has a strong affinity for other metal oxides such as alumina and titania (TiO 2 ) zirconia (ZrO 2 ), and therefore, these silica coatings have a strong affinity. A metal oxide coating 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 porous silicon carbide-based sintered body of the oxide film produced in this manner has a surface having properties equivalent to those of silica, alumina, titania and the like suitable as a catalyst carrier, and at the same time, as bulk properties, heat resistance, It can have the properties of silicon carbide having corrosion resistance and good thermal conductivity, and is a very 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２Ｈ型結晶よりなり、0.29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 described with reference to Examples of the present invention and Comparative Examples thereof. First, in the silicon carbide powder used as a starting material in Example 1 of the present invention, 94.6% by weight is β-type crystals and the balance is It consisted essentially of 2H type crystals, contained mainly 0.29% by weight of free carbon, 0.17% by weight of oxygen, 0.03% by weight of iron and 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18.7m2／ｇであった。The raw material powder had an average particle size of 0.28 μm, and its specific surface area was 18.7 m 2 / g.
上記炭化ケイォ粉末 100重量％に対し、ポリビニルアル
コール５重量％、水 300重量％を配合し、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 added to 100% by weight of the above-mentioned carbonized carbon powder, and the mixture was 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50kg／cm2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 sampled, granulated, and then molded at a pressure of 50 kg / cm 2 using a metal pressing die. As a result, the proportion of silicon carbide in this formed body was 42.9% by volume of the whole. .
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 green molded body was placed in a graphite crucible, which is a heat-resistant container, and fired in an atmosphere of mainly argon gas at 1 atm using a Tammann type firing furnace.
昇温過程は 450℃／時間で1400℃まで昇温し、1400℃か
ら1600までの間を 150℃／時間で昇温し、CO濃度を100
Pa以下にした。In the temperature raising process, the temperature is raised to 1400 ° C at 450 ° C / hour, the temperature is raised from 1400 ° C to 1600 at 150 ° C / hour, and the CO concentration is 100%.
Reduced to below Pa.
その後、最高温度1900℃まで 300℃／時間の割合で昇温
し、最高温度で４時間保持した。After that, the temperature was raised to a maximum temperature of 1900 ° C at a rate of 300 ° C / hour and kept at the maximum temperature for 4 hours.
なお、1500℃から1900℃までの温度範囲内でCO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。The CO concentration is 20% within the temperature range of 1500 ℃ to 1900 ℃.
The flow rate of the argon gas was appropriately adjusted so that the flow rate was within the range of 300 ± 50 Pa per minute.
得られた焼結体の密度は1.36ｇ／cm3であり、細孔容積
は0.42ml／ｇ、比表面積は17.9m2／ｇであり、この焼結
体の平均圧縮強度は1220kgf/cm2の高い値を有してい
た。The density of the obtained sintered body was 1.36 g / cm 3 , the pore volume was 0.42 ml / g, the specific surface area was 17.9 m 2 / g, and the average compressive strength of this sintered body was 1220 kgf / cm 2 Had a high value of.
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２Ｈ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、0.27μｍ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16.8m2／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 had 92.8% by weight of β-type crystals and the balance being substantially 2H-type crystals,
0.21 wt% free carbon, 0.17 wt% oxygen, 0.05 wt%
Of iron, 0.1% by weight of aluminum, 0.4% by weight of boron, and a silicon carbide powder having an average particle diameter of 0.27 μm, and its specific surface area was 16.8 m 2 / 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／cm
2であり、細孔容積は0.19ml／ｇであり、比表面積は
１．８m2／ｇと著しく低いものであった。Using this starting material, a silicon carbide-based sintered body was obtained in the same manner as in Example 1. The density of the sintered body was 1.97 g / cm 3.
2 , the pore volume was 0.19 ml / g, and the specific surface area was 1.8 m 2 / g, which was extremely low.
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.
11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, in the silicon carbide powder used as the starting material in Example 2 of the present invention, 96.3% by weight was β-type crystals, and the balance was substantially 2H-type crystals, and 0.81% by weight of free carbon, 0.
The raw material powder mainly contained 11% by weight of oxygen and 0.01% by weight of aluminum, and iron and boron were not detected.
また、この粉末の平均粒径は0.15μｍであり、比表面積
は51.2m2／ｇであった。The average particle size of this powder was 0.15 μm, and the specific surface area was 51.2 m 2 / g.
この出発原料100重量％に対し、比表面積128m2／ｇのカ
ーボンブラック粉末２重量％、ポリオキシエチレンノニ
ルフエニルエーテル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、ニーダーによ
って加圧混練した後、押し出し圧力20kgf/cm2で押出成
形を行い、径５mm、長さ５mmのペレットを成形した。To 100% by weight of this starting material, 2% by weight of carbon black powder having a specific surface area of 128 m 2 / g, 0.4% by weight of polyoxyethylene nonylphenyl ether, 20% by weight of water and 200% by weight of methylcellulose powder were added. After kneading under pressure with a kneader, extrusion molding was performed at an extrusion pressure of 20 kgf / cm 2 to form pellets having 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 compact 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。The molded body was degreased at 2 ° C./hour to 300 ° C., charged into a graphite crucible, and fired in a Tamman furnace in an atmosphere of mainly argon gas at 1 atm.
その昇温過程は1400℃まで 250℃／時間で昇温し、1400
℃から1500℃までの間を60℃／時間で昇温し、CO濃度を
100 Pa以下にした。The temperature rise process is 1400 ° C, which is heated at 250 ° C / hour.
Increase the CO concentration by raising the temperature from 60 ℃ to 1500 ℃ at 60 ℃ / hour.
Reduced to 100 Pa or less.
その後、最高温度1750℃まで 900℃／時間で昇温し、17
50℃で10分間保持したが、1500℃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 maximum temperature is raised to 1750 ℃ at 900 ℃ / hour, and
50 and ° C. at for 10 minutes, but all N 2 concentration atmosphere in the firing process after the 1500 ° C. was appropriately injected N 2 gas to be 500 ± 100 Pa.
得られた焼結体の密度は0.77ｇ／cm3であり、細孔容積
は0.99ml／ｇ、比表面積は38.1m2／ｇであり、この焼結
体の平均圧縮強度は550kgf／cm2の高い値を有してい
た。The density of the obtained sintered body was 0.77 g / cm 3 , the pore volume was 0.99 ml / g, the specific surface area was 38.1 m 2 / g, and the average compressive strength of this sintered body was 550 kgf / cm 2. Had a high value of.
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，固形分濃度約20％）を
蒸留水で２倍に希釈し、PH＝10に調整した。Further, as Example 3 of the present invention, for example, domestically produced colloidal silica (Snowtex 20, solid content concentration of about 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17.9m2／ｇ）を真空容器中に装入し、10
-2mmHg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 2 / g) obtained in Example 1 was charged in a vacuum vessel,
After degassing with -2 mmHg, the colloidal silica solution was injected 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、
乾燥器中 100℃で乾燥した後、シリコニット炉に装入
し、1400℃で、50重量％水蒸気−空気混合ガス５／分
流通下で５時間保持し焼成した。After purging, take out the sintered body from the colloidal silica solution,
After drying in a dryer at 100 ° C., it was placed in a silicon knit furnace, and baked at 1400 ° C. under a flow of 50 wt% steam-air mixed gas at 5 / min for 5 hours.
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16.8m2／ｇであった。The weight increase of the obtained silica-coated porous silicon carbide-based sintered body was 13.5%, and the specific surface area was 16.8 m 2 / g.
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。0.3 μm on the surface of silicon carbide by electron microscope observation
It was confirmed that the silica coating was formed at the 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 a domestically produced alumina sol (alumina sol-1000, solid content concentration 10%) to adjust PH = 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16.8m2／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-based sintered body (specific surface area: 16.8 m 2 / g) obtained in Example 3 was vacuum impregnated into the above alumina sol in the same manner as in Example 3 and taken out from the alumina sol. Then, it was dried in a dry atmosphere at 50 ° C.
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 placed in an Elema furnace and baked in air at 500 ° C. for 2 hours. .
得られたシリカ／アルミナ複合酸化物被覆の多孔質炭化
ケイ素焼結体の重量増加は８．２％、比表面積は52.5m2
／ｇであった。The obtained silica / alumina composite oxide-coated porous silicon carbide sintered body had a weight increase of 8.2% and a specific surface area of 52.5 m 2.
/ 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。Therefore, it was confirmed by electron microscope observation that an alumina coating was formed to a thickness of 0.15 μm on the surface of the silica-coated porous silicon carbide-based 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
質焼結体の表面にシリカ膜または／およびアルミナ膜か
らなる酸化物被膜を形成させることにより、高い比表面
積を付与できるのみならず、シリカおよびアルミナの有
する触媒担体として好適な特性と、炭化ケイ素質焼結体
の有する良好な耐熱性、耐蝕性、熱伝導性とを兼ね備え
た優れた触媒担体を提供できる。Therefore, in the present invention, an oxide film composed of a silica film and / or an alumina film is formed on the surface of a porous silicon carbide-based sintered body which has heat resistance, corrosion resistance, and properties required as a heat-resistant catalyst having good thermal conductivity. By forming it, not only it is possible to give a high specific surface area, but it also has the characteristics suitable as a catalyst carrier of silica and alumina and the good heat resistance, corrosion resistance, and thermal conductivity of the silicon carbide sintered body. An excellent catalyst carrier can be 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。The drawing is an enlarged view showing the structure of the porous body as a model.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭50−26795（ＪＰ，Ａ) 特開 昭50−53290（ＪＰ，Ａ) 特開 昭62−4446（ＪＰ，Ａ) ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-50-26795 (JP, A) JP-A-50-53290 (JP, A) JP-A-64-2446 (JP, A)
Claims (2)
の網目構造をなし、開放気孔を有し、細孔容積が0.2 〜
2.0 ml/gの範囲にあり、比表面積が３m2/g以上で、かつ
平均圧縮強度が300kgf/cm2以上である多孔質炭化ケイ素
質焼結体の表面に、シリカ膜または／およびアルミナ膜
の被覆を有しており、その比表面積が10m2/g以上である
触媒担体。1. A crystal mainly composed of silicon carbide has a three-dimensional network structure, has open pores, and has a pore volume of 0.2-.
A silica film and / or an alumina film is formed on the surface 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 300 kgf / cm 2 or more in the range of 2.0 ml / g. A catalyst carrier having a coating of 10 and having a specific surface area of 10 m 2 / g or more.
比表面積が３m2/g以上で、かつ平均圧縮強度が少なくと
も300kgf/cm2である多孔質炭化ケイ素質焼結体の表面に
シリカ膜または／およびアルミナ膜の被覆を有してお
り、その比表面積が10m2/g以上である触媒担体の製造方
法であって、(1)比表面積が３m2/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N2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℃〜200
0℃の最高温度で焼成する工程、および(4)生成する焼結
体にシリカ膜または／およびアルミナ膜を被覆する工
程、のシーケンスからなる、多孔質炭化ケイ素質焼結体
の表面にシリカ膜または／およびアルミナ膜の被覆を有
する触媒担体の製造方法。2. The pore volume is in the range of 0.2 to 2.0 ml / g,
The surface 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 has a silica film and / or an alumina film coating, A method for producing a catalyst carrier having a surface area of 10 m 2 / g or more, wherein (1) the specific surface area is 3 m 2 / g or more, and the total content of boron, aluminum and iron is 0 in terms of elements.
3% by weight or less of the step of molding the silicon carbide powder into a desired shape, (2) the molded body obtained by the step (1) is charged into a heat-resistant container, 1400 ℃ ~ 2000 ℃ In the temperature range of at least 10 minutes, the step of firing in a non-oxidizing atmosphere in which the gas partial pressure of at least one of CO or N 2 is maintained at 100 Pa or more, (3) the molded body 1600 ℃ ~ 200
A silica film on the surface of a porous silicon carbide sintered body, which comprises a sequence of a step of firing at a maximum temperature of 0 ° C., and a step of (4) coating the resulting sintered body with a silica film and / or an alumina film. Or / and a method for producing a catalyst carrier having a coating of an alumina film.
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 JPS6245344A (en) | 1987-02-27 |
| JPH0624636B2 true 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 (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000078451A1 (en) * | 1999-06-23 | 2000-12-28 | Ibiden Co., Ltd. | Carrier for catalyst and method for preparing the same |
| WO2006025498A1 (en) * | 2004-09-02 | 2006-03-09 | Ibiden Co., Ltd. | Honeycomb structure, method for production thereof and exhaust gas purification device |
| JP2010155241A (en) * | 1997-07-25 | 2010-07-15 | Centre National De La Recherche Scientifique (Cnrs) | Silicon carbide foam with high specific surface area and improved mechanical properties |
| US11772082B1 (en) * | 2018-06-21 | 2023-10-03 | Avn Corporation | Catalyst supports—composition and process of manufacture |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2731562B2 (en) * | 1988-12-29 | 1998-03-25 | イビデン株式会社 | Catalyst carrier and method for producing the same |
| 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 |
| EP2441513B1 (en) * | 2010-10-13 | 2013-08-07 | Ibiden Co., Ltd. | Honeycomb catalyst body and method for manufacturing honeycomb catalyst body |
| EP3448806A4 (en) | 2016-04-28 | 2019-11-27 | Indian Institute of Technology Delhi | Process for conversion of sulfur trioxide and hydrogen production |
Family Cites Families (3)
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|---|---|---|---|---|
| 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
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010155241A (en) * | 1997-07-25 | 2010-07-15 | Centre National De La Recherche Scientifique (Cnrs) | Silicon carbide foam with high specific surface area and improved mechanical properties |
| WO2000078451A1 (en) * | 1999-06-23 | 2000-12-28 | Ibiden Co., Ltd. | Carrier for catalyst and method for preparing the same |
| JP2001062302A (en) * | 1999-06-23 | 2001-03-13 | Ibiden Co Ltd | Catalyst carrier and production thereof |
| JP4642955B2 (en) * | 1999-06-23 | 2011-03-02 | イビデン株式会社 | Catalyst support and method for producing the same |
| WO2006025498A1 (en) * | 2004-09-02 | 2006-03-09 | Ibiden Co., Ltd. | Honeycomb structure, method for production thereof and exhaust gas purification device |
| JP5161458B2 (en) * | 2004-09-02 | 2013-03-13 | イビデン株式会社 | Manufacturing method of honeycomb structure |
| US11772082B1 (en) * | 2018-06-21 | 2023-10-03 | Avn Corporation | Catalyst supports—composition and process of manufacture |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6245344A (en) | 1987-02-27 |
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