JPH0436115B2 - - Google Patents
Info
- Publication number
- JPH0436115B2 JPH0436115B2 JP62102349A JP10234987A JPH0436115B2 JP H0436115 B2 JPH0436115 B2 JP H0436115B2 JP 62102349 A JP62102349 A JP 62102349A JP 10234987 A JP10234987 A JP 10234987A JP H0436115 B2 JPH0436115 B2 JP H0436115B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- raw material
- mullite
- sio
- weight
- 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
- 239000000843 powder Substances 0.000 claims description 55
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 claims description 48
- 229910052863 mullite Inorganic materials 0.000 claims description 48
- 239000002994 raw material Substances 0.000 claims description 46
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 33
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 31
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 23
- 239000007788 liquid Substances 0.000 claims description 22
- 239000013078 crystal Substances 0.000 claims description 19
- 238000001354 calcination Methods 0.000 claims description 14
- 238000004519 manufacturing process Methods 0.000 claims description 10
- 238000010304 firing Methods 0.000 claims description 4
- -1 aluminum silicate compound Chemical class 0.000 claims description 3
- 238000000465 moulding Methods 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims 5
- 150000001875 compounds Chemical class 0.000 description 28
- 238000005245 sintering Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 10
- 239000000203 mixture Substances 0.000 description 7
- 239000010936 titanium Substances 0.000 description 7
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 6
- 238000001035 drying Methods 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 2
- 238000000975 co-precipitation Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 238000003980 solgel method Methods 0.000 description 2
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- 239000005995 Aluminium silicate Substances 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 1
- YKTSYUJCYHOUJP-UHFFFAOYSA-N [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] Chemical compound [O--].[Al+3].[Al+3].[O-][Si]([O-])([O-])[O-] YKTSYUJCYHOUJP-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Natural products N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000000462 isostatic pressing Methods 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
- 239000011812 mixed powder Substances 0.000 description 1
- 239000011225 non-oxide ceramic Substances 0.000 description 1
- 229910052575 non-oxide ceramic Inorganic materials 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229910052573 porcelain Inorganic materials 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- XJDNKRIXUMDJCW-UHFFFAOYSA-J titanium tetrachloride Chemical compound Cl[Ti](Cl)(Cl)Cl XJDNKRIXUMDJCW-UHFFFAOYSA-J 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
Description
産業上の利用分野
本発明は、新規なムライト質焼結体及びその製
造方法に関する。
従来技術及びその問題点
ムライトセラミツクスは、古くから化学磁器、
耐火物等として利用されてきたが、その熱安定性
が非酸化物系セラミツクスに比して優れているこ
とから、最近耐熱性構造材料として脚光を浴びる
ようになつてきた。
従来ムライトセラミツクスは、カオリン、アル
ミナ等の天然原料から製造されている。この様な
セラミツクスにおいては、焼結性を改善するため
に、ムライトの組成よりはシリカが過剰に使用さ
れているので、原料中に含まれる不純物が過剰に
存在するシリカと結合して、焼結体中にガラス相
を多量に形成する。従つて、ムライト焼結体の熱
的性質は、このガラス相に支配され、高温強度が
低下する。
近年、Al2O3／SiO2比をコントロールして化学
的に高純度のムライト原料粉体を調製し、これを
使用してガラス相の少ないムライト質焼結体を製
造する試みがなされており（例えば特願昭61−
286264号）、従来のムライト質焼結体に比して高
温強度に優れた焼結体が得られている。しかしな
がら、この新しいムライト質焼結体においても、
実用的な観点からは、高温における耐クリープ特
性が不充分であり、耐熱性構造材料としては、よ
り一層の耐熱性の向上が要望されている。
問題点を解決する為の手段
本発明者は、従来技術の上記の如き問題点に鑑
みて、研究を進めた結果、Al2O3／SiO2比をコン
トロールするとともに、ムライトの結晶粒径を
2μｍ以上としたムライト焼結体が、優れた耐熱
性を発揮することを見い出した。
そして引続く研究において、本願発明者は、
Al2O3とSiO2の合計100重量部に対してTiO2を
0.02〜５重量％含有させる場合には、耐熱性特に
耐クリープ特性により優れたムライト焼結体が得
られることを見出した。
即ち、本発明は、下記のムライト焼結体及びそ
の製造方法を提供するものである：
() Al2O3／SiO2（重量比）が
73／27〜78／22の範囲内にあり、
() Al2O3とSiO2との合計100重量部に対し
TiO20.02〜５重量部を含み、
() 結晶粒径が2μｍ以上で、
() 主たる結晶相がムライト相からなること
を特徴とする耐熱性ムライト質焼結体；
及び
() Al2O3／SiO2（重量比）が
73／27〜78／22の範囲内にあり、且つ
() Al2O3とSiO2との合計100重量部に対し
TiO20.02〜５重量部を含む粉体原料を成形
した後、焼成することを特徴とする
() Al2O3／SiO2（重量比）が
73／27〜78／22の範囲内にあり、
() Al2O3とSiO2との合計100重量部に対し
TiO20.02〜５重量部を含み、
() 結晶粒径が2μｍ以上で、
() 主たる結晶相がムライト相からなる耐熱
性ムライト質焼結体の製造方法。
本発明によるムライト焼結体は、下記の各要件
を充足する必要がある。
() Al2O3とSiO2との配合割合は、
Al2O3／SiO2＝73／27〜78／22（重量比）の範
囲内とする。この範囲内で特に焼結体の耐クリ
ープ性が高くなる。SiO2が過剰となると、焼
結工程でSiO2又は非晶質相が生成し易くなり、
常温における強度等は向上するが、耐クリープ
性が低下するので、好ましくない。一方、
Al2O3が過剰になりすぎると、アルミナが多量
に析出し、またムライト結晶が針状から粒状に
変つてアスペクト比の小さな結晶となるととも
に強度及び耐熱性が低下し、耐クリープ性も低
下する。Al2O3／SiO2＝73／27〜77／23とする
ことがより好ましい。
() TiO2の含有量は、Al2O3と
SiO2との合計量に対し、0.02〜５重量部とす
る。この範囲内の量が、焼結体の耐熱性向上に
特に顕著な効果を奏する。TiO2の含有量が
0.02重量部未満の場合には、ムライト結晶への
固溶量が少なくなるので、配合効果が充分に発
揮されない。一方、TiO2の含有量が５重量％
を上回る場合には、Al2O3とTiO2との化合物や
TiO2が結晶粒界層に析出するため、焼結体の
機械的特性の低下を招く。TiO2の含有量は、
0.1〜３重量部とすることがより好ましい。
TiO2の存在は、焼結温度を低下させる利点を
も生ずる。
() 焼結体中のムライト結晶の粒径を2.0μｍ以
上とする。結晶粒径が2.0μｍを下回る場合に
は、焼結体の耐クリープ特性が充分には改善さ
れない。ムライト結晶の粒径は、2.5μｍ以上で
あることがより好ましい。尚、焼結体の製造を
以下に示す本発明方法により行なう場合には、
ムライト結晶の粒径は、最大20μｍ程度であ
り、この様な焼結体は、所望の優れた性能を発
揮する。
() 焼結体中の結晶相が主にムライト晶からな
つている。上記Al2O3とSiO2との割合において
は、アルミナ相が５％程度まで含まれる場合が
あるが、これによつて焼結体の物性が阻害され
ることはない。
本発明焼結体は、通常かさ密度3.00ｇ／cm3以上
で且つ室温強度25Kgｆ／mm2以上の特性を有しお
り、適切な製造条件で製造されるものは、かさ密
度3.05ｇ／cm3以上で且つ室温強度30Kgｆ／mm2以上
の特性を有する場合がある。
尚、本発明のムライト質焼結体は、その重量の
２％を上限として、ZrO2、Cr2O3等を含んでいて
も良い。この許容版以内であれば、焼結体の物性
に悪影響を及ぼすことはなく、靭性や強度を向上
させたり、焼結を促進する効果が得られることが
ある。又、アルカリ金属酸化物の含有量は、0.1
重量％以下とすることが好ましい。
本発明焼結体を製造するには、Al2O3とSiO2と
の比が所定の範囲内にあり、この両者に対する
TiO2の割合が所定の範囲内にあり、且つAl2O3と
SiO2とからなる主たる成分が予め仮焼によりム
ライト化している粉体原料を常法に従つて成形
し、焼結する。この様な粉体原料は、液体原料を
使用する公知の種々の方法で調製可能であり、製
造方法は、特に限定されない。具体的には、ゾル
ーゲル法、共沈法、液状原料から水分を蒸発させ
て粉体化する方法、液状原料を噴霧して熱分解す
る方法等により得た粉体を900〜1500℃程度の温
度で、好ましくは1000〜1350℃程度の温度で仮焼
する方法等が例示される。
最も一般的な方法である共沈法の場合には、例
えば、メライト質成形焼結体中のAl／Si／Ti比
に相当するAl化合物、Si化合物及びTi化合物を
含む液状原料を調製し、均一となるまで混合し、
各化合物を共沈させた後、乾燥して、粉体を得
る。次いで、ムライト形成温度である900〜1500
℃で仮焼した後、粉砕して分散させ、好ましくは
平均粒径2μｍ以下の焼結用の粉体原料とすれば
よい。或いは、ムライト質成形焼結体中のAl／
Si比に相当するAl化合物及びSi化合物を含む液
状原料を調製し、均一となるまで混合し、両化合
物を共沈させた後、乾燥して、粉体を得る。次い
で、900〜1500℃で仮焼した後、これにTiO2粉末
を加え、全体を粉砕して分散させ、焼結用の粉体
原料としても良い。或いは更に、ムライト質成形
焼結体中のAl／Si比よりも低い割合でAl化合物
及びSi化合物を含む液状原料を調製し、均一とな
るまで混合し、両化合物を共沈させた後、乾燥し
て、粉体を得る。次いで、900〜1500℃で仮焼し
た後、これにAl2O3粉末及びTiO2粉末を加え、全
体を粉砕して分散させ、焼結用の粉体原料として
も良い。或は、ムライト質焼結体中のAl／Si比
に相当するAl化合物及びSi化合物を含む液状原
料を調製し、均一となるまで混合し、両化合物を
共沈させた後、乾燥して、粉体を得る。次いで、
900〜1500℃で仮焼した後、これにケイ酸アルミ
ニウム化合物粉末及びTiO2粉末を加え、全体を
粉砕して分散させ、焼結用の粉体原料としても良
い。或いは更に、ムライト質成形焼結体中の
Al／Si比に相当する割合でAl化合物及びSi化合
物を含む液状原料を調製し、均一となるまで混合
し、両化合物を共沈させた後、乾燥して、粉体を
得る。次いで、900〜1500℃で仮焼した後、これ
をTiを含む液状原料に加えて調製した粉体を粉
砕して分散させ、焼結用の粉体原料としても良
い。
更に、やはり一般的な方法であるゾル−ゲル法
による場合には、例えば、ムライト質焼結体中の
Al／Si／Ti比に相当するAl化合物、Si化合物及
びTi化合物を含む液状原料を調製し、均一とな
るまで混合し、PHの調製により或は乾燥によりゲ
ルを得、これを900〜1500℃で仮焼した後、粉砕
して分散させ、好ましくは平均粒径2μｍ以下の
焼結用の粉体原料とすれば良い。或は、ムライト
質焼結体中のAl／Si比に相当するAl化合物及び
Si化合物を含む液状原料を調製し、均一となるま
で混合し、PHの調製により或は乾燥によりゲルを
得、これを900〜1500℃で仮焼した後、TiO2粉末
を加え、全体を粉砕して分散させ、焼結用の粉体
原料としても良い。或は更に、ムライト質焼結体
中のAl／Si比よりも低い割合でAl化合物及びSi
化合物を含む液状原料を調製し、均一となるまで
混合し、PHの調製により或は乾燥によりゲルを
得、これを900〜1500℃で仮焼した後、Al2O3粉
末及びTiO2粉末を加え、全体を粉砕して分散さ
せ、焼結用の粉体原料としても良い。更に、ムラ
イト質焼結体中のAl／Si比に相当する割合でAl
化合及びSi化合物を含む液状原料を調製し、均一
となるまで混合し、PHの調整により或は乾燥によ
りゲルを得、これを900〜1500℃で仮焼した後、
ケイ酸アルミニウム粉末及びTiO2粉末を加え、
全体を粉砕して分散させ、焼結用の粉体原料とし
ても良い。更に又、ムライト質焼結体中のAl／
Si比に相当するAl化合物及びSi化合物を含む液
状原料を調製し、均一となるまで混合し、PHの調
製により或は乾燥によりゲルを得、これを900〜
1500℃で仮焼した後、Tiを含む液状原料を加え、
全体を粉砕して分散させ、焼結用の粉体原料とし
ても良い。
粉体原料製造の為のAl源としては、アルミナ
ゾル、塩化アルミニウム、硫酸アルミニウム、硝
酸アルミニウム等が使用され、Si源としては、シ
リカゾル、エチルシリケート等が使用され、Ti
源としては、塩化チタニウム、チタンアルコキシ
ド等がそれぞれ通常使用される。
上記の様にして製造された原料粉体は、常法に
従つて成形され、1550〜1800℃程度で焼結され
て、本発明のムライト質焼結体となる。
発明の効果
本発明のムライト質焼結体は、高温における耐
クリープ性及び熱安定性、高温強度等に優れてい
るので、高温用ローラー、高温用治具、炉心管、
保護管等として有用である。
実施例
以下に実施例を示し、本発明の特徴とするとこ
ろをより一層明らかにする。
実施例 １
0.5モル％塩化アルミニウム溶液とSiO2分10重
量％のシリカゾルとを混合して、第１表に示す通
りのAl2O3及びSiO2としての重量比を有する均一
な液状原料を得た後、アンモニア水を加えて中和
共沈させ、得られた沈澱物を乾燥し、1250℃で８
時間焼成して、ムライト粉体を得た。このムライ
ト粉体100重量部に所定量のTiO2粉体を加え、粉
砕して分散させた後、混合粉体重量の２％のポリ
ビニルアルコールを加え、静水圧成形法により成
形圧１トン／cm2で60×60×５mmの板状に成形し、
1650℃で２時間焼成してムライト質焼結体（アル
カリ金属酸化物含有量0.1％以下）を得た。
第１表にその結果を示す。尚、第１表における
各項目は、それぞれ以下の事項を示す。
()…Al2O3／SiO2（重量比）
()…TiO2（重量部）
()…ムライト結晶粒径（μｍ）
()…歪み速度（１／ｈ；1500℃、２Kgｆ／mm2の
応力で測定）
INDUSTRIAL APPLICATION FIELD The present invention relates to a novel mullite sintered body and a method for producing the same. Prior art and its problems Mullite ceramics has been used for a long time as chemical porcelain,
Although it has been used as a refractory, it has recently come into the spotlight as a heat-resistant structural material because its thermal stability is superior to non-oxide ceramics. Conventionally, mullite ceramics are manufactured from natural raw materials such as kaolin and alumina. In such ceramics, in order to improve sinterability, silica is used in excess of the mullite composition, so impurities contained in the raw materials combine with the excess silica and cause sintering. Forms a large amount of glass phase in the body. Therefore, the thermal properties of the mullite sintered body are dominated by this glass phase, and the high-temperature strength is reduced. In recent years, attempts have been made to control the Al 2 O 3 /SiO 2 ratio to chemically prepare high-purity mullite raw material powder, and use this to manufacture mullite sintered bodies with little glass phase. (For example, patent application 1986-
No. 286264), a sintered body with superior high-temperature strength compared to conventional mullite sintered bodies has been obtained. However, even in this new mullite sintered body,
From a practical point of view, the creep resistance at high temperatures is insufficient, and as a heat-resistant structural material, further improvement in heat resistance is desired. Means for Solving the Problems In view of the above-mentioned problems of the prior art, the inventors of the present invention have conducted research, and as a result, they have controlled the Al 2 O 3 /SiO 2 ratio and the crystal grain size of mullite.
It has been discovered that a mullite sintered body with a thickness of 2 μm or more exhibits excellent heat resistance. In subsequent research, the inventor of the present application
TiO 2 for a total of 100 parts by weight of Al 2 O 3 and SiO 2
It has been found that when the content is 0.02 to 5% by weight, a mullite sintered body having excellent heat resistance, particularly creep resistance, can be obtained. That is, the present invention provides the following mullite sintered body and its manufacturing method: () Al 2 O 3 /SiO 2 (weight ratio) is within the range of 73/27 to 78/22, () For a total of 100 parts by weight of Al 2 O 3 and SiO 2
A heat-resistant mullite sintered body containing 0.02 to 5 parts by weight of TiO 2 , () having a crystal grain size of 2 μm or more, () having a main crystal phase consisting of a mullite phase; and () Al 2 O 3 /SiO 2 (weight ratio) is within the range of 73/27 to 78/22, and () per 100 parts by weight of Al 2 O 3 and SiO 2 in total
It is characterized by molding a powder raw material containing 0.02 to 5 parts by weight of TiO 2 and then firing it () Al 2 O 3 /SiO 2 (weight ratio) is within the range of 73/27 to 78/22. , () for a total of 100 parts by weight of Al 2 O 3 and SiO 2
A method for producing a heat-resistant mullite sintered body containing 0.02 to 5 parts by weight of TiO 2 , () having a crystal grain size of 2 μm or more, and () having a mullite phase as the main crystal phase. The mullite sintered body according to the present invention needs to satisfy the following requirements. () The blending ratio of Al 2 O 3 and SiO 2 is within the range of Al 2 O 3 /SiO 2 =73/27 to 78/22 (weight ratio). Within this range, the creep resistance of the sintered body becomes particularly high. If SiO 2 is in excess, SiO 2 or amorphous phase is likely to be generated during the sintering process.
Although strength and the like at room temperature are improved, creep resistance is lowered, which is not preferable. on the other hand,
If Al 2 O 3 is excessive, a large amount of alumina will precipitate, and mullite crystals will change from needle-like to granular, resulting in crystals with a small aspect ratio, and the strength and heat resistance will decrease, as well as creep resistance. do. It is more preferable that Al 2 O 3 /SiO 2 =73/27 to 77/23. () The content of TiO 2 is 0.02 to 5 parts by weight based on the total amount of Al 2 O 3 and SiO 2 . An amount within this range has a particularly remarkable effect on improving the heat resistance of the sintered body. The content of TiO2
If the amount is less than 0.02 parts by weight, the amount of solid solution in the mullite crystals will be small, so the blending effect will not be sufficiently exerted. On the other hand, the content of TiO 2 is 5% by weight
If the amount exceeds , compounds of Al 2 O 3 and TiO
TiO 2 precipitates in the grain boundary layer, leading to a decrease in the mechanical properties of the sintered body. The content of TiO2 is
More preferably, the amount is 0.1 to 3 parts by weight.
The presence of TiO 2 also has the advantage of lowering the sintering temperature. () The grain size of mullite crystals in the sintered body is 2.0 μm or more. If the crystal grain size is less than 2.0 μm, the creep resistance of the sintered body will not be sufficiently improved. The grain size of the mullite crystals is more preferably 2.5 μm or more. In addition, when manufacturing the sintered body by the method of the present invention shown below,
The grain size of mullite crystals is approximately 20 μm at maximum, and such a sintered body exhibits the desired excellent performance. () The crystalline phase in the sintered body is mainly composed of mullite crystals. In the above ratio of Al 2 O 3 and SiO 2 , up to about 5% alumina phase may be included, but this does not impair the physical properties of the sintered body. The sintered body of the present invention usually has a bulk density of 3.00 g/cm 3 or more and a room temperature strength of 25 Kgf/mm 2 or more, and those manufactured under appropriate manufacturing conditions have a bulk density of 3.05 g/cm 3 or more. and may have a room temperature strength of 30 Kgf/mm 2 or more. The mullite sintered body of the present invention may contain ZrO 2 , Cr 2 O 3 , etc. up to 2% of its weight. If it is within this allowable range, it will not adversely affect the physical properties of the sintered body, and may have the effect of improving toughness and strength and promoting sintering. In addition, the content of alkali metal oxide is 0.1
It is preferable that the amount is less than % by weight. In order to produce the sintered body of the present invention, the ratio of Al 2 O 3 and SiO 2 must be within a predetermined range, and
The proportion of TiO 2 is within the specified range, and the proportion of Al 2 O 3 is within the specified range.
A powder raw material whose main component is SiO 2 which has been previously converted into mullite by calcination is shaped and sintered according to a conventional method. Such powder raw materials can be prepared by various known methods using liquid raw materials, and the manufacturing method is not particularly limited. Specifically, powder obtained by a sol-gel method, a coprecipitation method, a method of evaporating water from a liquid raw material to powder it, a method of spraying a liquid raw material and thermally decomposing it, etc. is heated to a temperature of about 900 to 1500°C. For example, a method of calcining preferably at a temperature of about 1000 to 1350°C is exemplified. In the case of the coprecipitation method, which is the most common method, for example, a liquid raw material containing an Al compound, a Si compound, and a Ti compound corresponding to the Al/Si/Ti ratio in the melitic shaped sintered body is prepared, Mix until homogeneous;
After each compound is coprecipitated, it is dried to obtain a powder. Then the mullite forming temperature is 900-1500
After calcining at °C, it is pulverized and dispersed to obtain a powder raw material for sintering, preferably having an average particle size of 2 μm or less. Or Al/in mullite shaped sintered body
A liquid raw material containing an Al compound and a Si compound corresponding to the Si ratio is prepared, mixed until uniform, both compounds are co-precipitated, and then dried to obtain a powder. Next, after calcining at 900 to 1500°C, TiO 2 powder is added thereto, and the whole is pulverized and dispersed, which may be used as a powder raw material for sintering. Alternatively, a liquid raw material containing an Al compound and a Si compound at a lower ratio than the Al/Si ratio in the mullite shaped sintered body is prepared, mixed until uniform, both compounds are co-precipitated, and then dried. to obtain powder. Next, after calcining at 900 to 1500°C, Al 2 O 3 powder and TiO 2 powder are added thereto, and the whole is pulverized and dispersed to be used as a powder raw material for sintering. Alternatively, a liquid raw material containing an Al compound and a Si compound corresponding to the Al/Si ratio in the mullite sintered body is prepared, mixed until uniform, both compounds are co-precipitated, and then dried. Get powder. Then,
After calcining at 900 to 1500°C, aluminum silicate compound powder and TiO 2 powder are added thereto, and the whole is pulverized and dispersed to be used as a powder raw material for sintering. Alternatively, in the mullite shaped sintered body
A liquid raw material containing an Al compound and a Si compound in a proportion corresponding to the Al/Si ratio is prepared, mixed until uniform, both compounds are co-precipitated, and then dried to obtain a powder. Next, after calcining at 900 to 1500° C., this is added to a liquid raw material containing Ti, and the prepared powder is pulverized and dispersed to be used as a powder raw material for sintering. Furthermore, when using the sol-gel method, which is also a general method, for example,
Prepare a liquid raw material containing an Al compound, a Si compound and a Ti compound corresponding to the Al/Si/Ti ratio, mix until homogeneous, obtain a gel by adjusting the pH or drying, and heat it at 900 to 1500℃. After calcination, the powder is pulverized and dispersed to obtain a powder raw material for sintering, preferably having an average particle size of 2 μm or less. Alternatively, an Al compound corresponding to the Al/Si ratio in the mullite sintered body and
Prepare liquid raw materials containing Si compounds, mix until homogeneous, obtain gel by adjusting pH or drying, calcining this at 900-1500℃, then add TiO 2 powder and crush the whole. It may be dispersed and used as a powder raw material for sintering. Alternatively, Al compounds and Si may be contained in a lower proportion than the Al/Si ratio in the mullite sintered body.
Prepare a liquid raw material containing a compound, mix it until it becomes homogeneous, obtain a gel by adjusting the pH or drying it, calcining it at 900-1500℃, and then add Al 2 O 3 powder and TiO 2 powder. In addition, the whole material may be pulverized and dispersed to be used as a powder raw material for sintering. Furthermore, Al is added in a proportion corresponding to the Al/Si ratio in the mullite sintered body.
Prepare a liquid raw material containing a compound and a Si compound, mix until homogeneous, obtain a gel by adjusting the pH or drying, and after calcining this at 900 to 1500 ° C.
Add aluminum silicate powder and TiO2 powder,
The entire product may be pulverized and dispersed to be used as a powder raw material for sintering. Furthermore, Al/
Prepare a liquid raw material containing an Al compound and a Si compound corresponding to the Si ratio, mix it until it becomes homogeneous, obtain a gel by adjusting the pH or drying it, and add it to 900~
After calcining at 1500℃, liquid raw materials containing Ti are added,
The entire product may be pulverized and dispersed to be used as a powder raw material for sintering. Alumina sol, aluminum chloride, aluminum sulfate, aluminum nitrate, etc. are used as Al sources for powder raw material production, and silica sol, ethyl silicate, etc. are used as Si sources.
As the source, titanium chloride, titanium alkoxide, etc. are usually used. The raw material powder produced as described above is molded according to a conventional method and sintered at about 1550 to 1800°C to obtain the mullite sintered body of the present invention. Effects of the Invention The mullite sintered body of the present invention has excellent creep resistance, thermal stability, and high-temperature strength at high temperatures, so it can be used in high-temperature rollers, high-temperature jigs, furnace tubes, etc.
Useful as a protection tube, etc. Examples Examples are shown below to further clarify the features of the present invention. Example 1 A 0.5 mol% aluminum chloride solution and a 10 wt% SiO 2 silica sol were mixed to obtain a homogeneous liquid raw material having the weight ratio as Al 2 O 3 and SiO 2 as shown in Table 1. After that, aqueous ammonia was added to neutralize and coprecipitate, and the resulting precipitate was dried and heated at 1250°C for 8
After firing for a period of time, mullite powder was obtained. A predetermined amount of TiO 2 powder was added to 100 parts by weight of this mullite powder, crushed and dispersed, then polyvinyl alcohol of 2% of the weight of the mixed powder was added, and the molding pressure was 1 ton/cm by isostatic pressing. 2. Form into a plate shape of 60 x 60 x 5 mm.
A mullite sintered body (alkali metal oxide content: 0.1% or less) was obtained by firing at 1650°C for 2 hours. Table 1 shows the results. Note that each item in Table 1 indicates the following items. ()...Al 2 O 3 /SiO 2 (weight ratio) ()...TiO 2 (parts by weight) ()...Mullite crystal grain size (μm) ()...Strain rate (1/h; 1500°C, 2Kgf/mm 2 (measured at stress of)
【表】
本発明のムライト質焼結体No.１〜５は、歪み速
度が小さく、優れた耐クリープ性を備えているこ
とが明らかである。
実施例 ２
実施例１と同様の手順により、TiO2含有量
0.05％（Al2O3とSiO2との合計重量に対し）、ムラ
イト結晶粒径2.3μｍで
Al2O3とSiO2との重量比が種々異なるムライト
質焼結体を製造した。
第１図にAl2O3／SiO2比と歪み速度（１／ｈ）
との関係を示す。
Al2O3／SiO2比が73／27〜78／22の範囲で良好
な耐クリープ性が得られている。[Table] It is clear that the mullite sintered bodies Nos. 1 to 5 of the present invention have low strain rates and excellent creep resistance. Example 2 The TiO 2 content was determined by the same procedure as in Example 1.
Mullite sintered bodies having different weight ratios of Al 2 O 3 and SiO 2 with a mullite crystal grain size of 0.05% (based on the total weight of Al 2 O 3 and SiO 2 ) of 2.3 μm were produced. Figure 1 shows the Al 2 O 3 /SiO 2 ratio and strain rate (1/h).
Indicates the relationship between Good creep resistance was obtained when the Al 2 O 3 /SiO 2 ratio was in the range of 73/27 to 78/22.
第１図は、ムライト質焼結体におけるAl2O3／
SiO2比と耐クリープ性との関係を示すグラフで
ある。
Figure 1 shows Al 2 O 3 /
It is a graph showing the relationship between SiO 2 ratio and creep resistance.
Claims (1)
TiO20.02〜５重量部を含み、 () 結晶粒径が2μｍ以上で、 () 主たる結晶相がムライト相からなることを
特徴とする耐熱性ムライト質焼結体。 ２ () Al2O3／SiO2（重量比）が 73／27〜78／22の範囲内にあり、且つ () Al2O3とSiO2との合計100重量部に対し
TiO20.02〜５重量部を含む粉体原料を成形し
た後、焼成することを特徴とする () Al2O3／SiO2（重量比）が 73／27〜78／22の範囲内にあり、 () Al2O3とSiO2との合計100重量部に対し
TiO20.02〜５重量部を含み、 () 結晶粒径が2μｍ以上で、 () 主たる結晶相がムライト相からなる耐熱
性ムライト質焼結体の製造方法。 ３ (イ) 所定の割合でAlとSiとTiとを含む液状
原料から調製した粉体を900〜1500℃で仮焼し
て得た粉体原料、 (ロ) AlとSiとを含む液状原料から調製した粉体
を900〜1500℃で仮焼し、これにTiO2粉末を加
えて得た粉体原料、 (ハ) AlとSiとを含む液状原料から調製した粉体
を900〜1500℃で仮焼し、これにAl2O3粉末及
びTiO2粉末を加えて得た粉体原料、 (ニ) AlとSiとを含む液状原料から調製した粉体
を900〜1500℃で仮焼し、これにケイ酸アルミ
ニウム化合物粉末及び TiO2粉末を加えて得た粉体原料、又は (ホ) AlとSiとを含む液状原料から調製した粉体
を900〜1500℃で仮焼し、これをTiを含む液状
原料に加えて得た粉体原料 を粉砕して分散させた後、成形し、焼成する特許
請求の範囲第２項に記載の耐熱性ムライト質焼結
体の製造方法。[Claims] 1 () Al 2 O 3 /SiO 2 (weight ratio) is within the range of 73/27 to 78/22, and () Al 2 O 3 and SiO 2 are in a total of 100 parts by weight. Against
A heat-resistant mullite-based sintered body containing 0.02 to 5 parts by weight of TiO 2 , () having a crystal grain size of 2 μm or more, and () having a main crystal phase consisting of a mullite phase. 2 () Al 2 O 3 /SiO 2 (weight ratio ) is in the range of 73/27 to 78/22, and ()
It is characterized by molding a powder raw material containing 0.02 to 5 parts by weight of TiO 2 and then firing it. () Al 2 O 3 /SiO 2 (weight ratio) is within the range of 73/27 to 78/22. , () for a total of 100 parts by weight of Al 2 O 3 and SiO 2
A method for producing a heat-resistant mullite sintered body containing 0.02 to 5 parts by weight of TiO 2 , () having a crystal grain size of 2 μm or more, and () having a mullite phase as the main crystal phase. 3 (a) A powder raw material obtained by calcining a powder prepared from a liquid raw material containing Al, Si, and Ti in a predetermined ratio at 900 to 1500°C, (b) A liquid raw material containing Al and Si. Powder raw material obtained by calcining the powder prepared from 900 to 1500℃ and adding TiO 2 powder to it, (c) Powder prepared from a liquid raw material containing Al and Si at 900 to 1500℃ A powder raw material obtained by adding Al 2 O 3 powder and TiO 2 powder to the powder, and (d) a powder prepared from a liquid raw material containing Al and Si is calcined at 900 to 1500 °C. A powder raw material obtained by adding aluminum silicate compound powder and TiO 2 powder to this, or (e) a powder prepared from a liquid raw material containing Al and Si is calcined at 900 to 1500 ° C. The method for producing a heat-resistant mullite sintered body according to claim 2, wherein the powder raw material obtained in addition to the liquid raw material containing Ti is pulverized and dispersed, then molded and fired.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62102349A JPS63270352A (en) | 1987-04-24 | 1987-04-24 | Sintered material of heat-resistant mullite and production thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62102349A JPS63270352A (en) | 1987-04-24 | 1987-04-24 | Sintered material of heat-resistant mullite and production thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63270352A JPS63270352A (en) | 1988-11-08 |
| JPH0436115B2 true JPH0436115B2 (en) | 1992-06-15 |
Family
ID=14325006
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62102349A Granted JPS63270352A (en) | 1987-04-24 | 1987-04-24 | Sintered material of heat-resistant mullite and production thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63270352A (en) |
-
1987
- 1987-04-24 JP JP62102349A patent/JPS63270352A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63270352A (en) | 1988-11-08 |
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