JP2757031B2 - Method for producing mullite sintered body - Google Patents
Method for producing mullite sintered bodyInfo
- Publication number
- JP2757031B2 JP2757031B2 JP1204627A JP20462789A JP2757031B2 JP 2757031 B2 JP2757031 B2 JP 2757031B2 JP 1204627 A JP1204627 A JP 1204627A JP 20462789 A JP20462789 A JP 20462789A JP 2757031 B2 JP2757031 B2 JP 2757031B2
- Authority
- JP
- Japan
- Prior art keywords
- sintered body
- sio
- mullite
- cristobalite
- present
- 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
- 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 title claims description 23
- 229910052863 mullite Inorganic materials 0.000 title claims description 22
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 27
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 16
- 229910052906 cristobalite Inorganic materials 0.000 claims description 16
- 239000011148 porous material Substances 0.000 claims description 12
- 239000002243 precursor Substances 0.000 claims description 12
- 238000000137 annealing Methods 0.000 claims description 11
- 239000011521 glass Substances 0.000 claims description 10
- 239000002344 surface layer Substances 0.000 claims description 10
- 238000000034 method Methods 0.000 description 21
- 238000005245 sintering Methods 0.000 description 14
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 7
- 238000001035 drying Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000002131 composite material Substances 0.000 description 3
- 238000005470 impregnation Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 230000000171 quenching effect Effects 0.000 description 2
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 229910003902 SiCl 4 Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000002003 electron diffraction Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007654 immersion 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
- 239000007788 liquid Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、ムライト質焼結体の表層の開気孔にSiO2前
駆体を充填し、加熱処理してクリストバライト化するこ
とによって、該焼結体の破壊靭性を改良するムライト質
焼結体の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for filling cristobalite by filling an open pore in a surface layer of a mullite sintered body with a SiO 2 precursor and subjecting it to cristobalite by heat treatment. The present invention relates to a method for producing a mullite sintered body that improves the fracture toughness of the body.
従来、ムライト質焼結体は、耐熱性、耐薬品性等多く
の特徴を有するため、種々の凡用部品への使用が試みら
れている。BACKGROUND ART Conventionally, a mullite sintered body has many characteristics such as heat resistance and chemical resistance, and therefore, its use in various general parts has been attempted.
そのムライト質焼結体を部品として常用した場合、外
力によりチッピングすることが多く、その都度部品を取
替えねばならい。これは該焼結体の破壊靭性（K1C）が
2.0MPa・ｍ1/2程度と著しく低いことに起因して起こる
現象である。When the mullite sintered body is commonly used as a part, chipping often occurs due to external force, and the part must be replaced each time. This is because the fracture toughness (K 1C )
This phenomenon is caused by a remarkably low level of about 2.0 MPa · m 1/2 .
そのK1Cを改良しようとして諸々の研究が行われた。
例えば、ムライト質焼結体を製造するにあたって、焼結
時間を長くしたり、あるいは冷却した焼結体を再加熱す
るなどであるが、その結果をほとんど顧みるべきものが
なかった。Various studies have been performed in an attempt to improve its K 1C.
For example, when producing a mullite sintered body, the sintering time is lengthened, or a cooled sintered body is reheated, but there has been almost no result to be taken into account.
また、先に本願出願人は、目的は異なるが、ムライト
質粉末に炭化ケイ素など第三物質を配合した混合物から
製造した焼結体を再加熱する方法（特開昭64−72961）
を提案したが、この製法で得られた焼結体のK1Cは、2.5
〜3.0MPa・ｍ1/2程度であった。Further, the applicant of the present application has previously disclosed a method of reheating a sintered body produced from a mixture of a mullite powder and a third substance such as silicon carbide, for a different purpose (Japanese Patent Application Laid-Open No. 64-72961).
Proposed While, K 1C of the sintered bodies obtained in this process is 2.5
3.03.0 MPa · m 1/2 .
前述の製法で作られた複合ムライト質焼結体は、ムラ
イト質粉末単味から製造された焼結体に比し、そのK1C
が約1.5倍近く向上し、それなりの効果は認められた。The composite mullite sintered body produced by the above-mentioned method has a K 1C
Was improved by about 1.5 times, and a certain effect was recognized.
しかしながら、その複合ムライト質焼結体であって
も、依然として前述した各種部品として、例えば可動部
の部品として使用した場合、特に辺においてチッピング
がしばしば起こり、信頼性にも欠けていたため、ムライ
ト質焼結体のK1Cの一層の改良が切望されていた。However, even when the composite mullite sintered body is used as the above-mentioned various parts, for example, as a part of a movable part, chipping often occurs particularly on the side and lacks reliability, so that the mullite sintering is not performed. further improvement of K 1C of sintered has been desired.
そこで、本発明者らは、チッピングが焼結体の表層で
起こる点に着目し、該表層を集中的に補強することを研
究した結果、表層の開気孔をクリストバライトで充填す
れば、K1Cの改良に有効であることを知見して、本発明
を完成させた。Therefore, the present inventors have focused on the point that chipping occurs on the surface layer of the sintered body, and as a result of studying that the surface layer is intensively reinforced, if the open pores of the surface layer are filled with cristobalite, K 1C The inventors have found that the present invention is effective for improvement and completed the present invention.
すなわち、本発明の要旨は、開気孔率20〜40容量％の
ムライト質予備焼結体（以下、単に予備焼結体という）
の開気孔にSiO2前駆体を充填したのち、本焼結し、1450
〜1580℃でアニール処理することにより、該焼結体の表
層に存在するSiO2系ガラス相をクリストバライト化する
ことを特徴とするムライト質焼結体の製造方法にある。That is, the gist of the present invention is that a mullite pre-sintered body having an open porosity of 20 to 40% by volume (hereinafter, simply referred to as a pre-sintered body)
After filling the open pores with the SiO 2 precursor,
An object of the present invention is to provide a method for producing a mullite sintered body, wherein an anneal treatment is performed at about 1580 ° C. to convert the SiO 2 -based glass phase present in the surface layer of the sintered body into cristobalite.
以下、本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail.
本発明は、予備焼結体の開気孔をクリストバライトで
満たすと共に、周辺に存在するムライトおよび／または
α−Al2O3と結合させて、その表層を改質し、ムライト
質焼結体のK1Cを改良しようとする方法である。The present invention fills the open pores of the pre-sintered body with cristobalite, binds to the surrounding mullite and / or α-Al 2 O 3 , modifies the surface layer thereof, and improves the K of the mullite sintered body. This is a way to improve 1C .
そのクリストバライトは微小な開気孔に直接充填する
ことはできない。したがって、本発明では液相あるいは
気相のSiO2前駆体を開気孔に充填し、焼結し、アニール
処理することにより、究極的に表層にクリストバライト
として散在させる方法を用いた。クリストバライトは化
学的にはSiO2で示され、理論的には1450℃以上で生成
し、急冷することによって安定相となる。The cristobalite cannot directly fill the tiny open pores. Therefore, in the present invention, a method of filling the open pores with the liquid or gaseous SiO 2 precursor, sintering and annealing to ultimately disperse the cristobalite in the surface layer is used. Cristobalite is chemically represented by SiO 2 and theoretically forms at 1450 ° C. or higher and becomes a stable phase by quenching.
本発明で使用する予備焼結体は、常法にしたがって製
造されたものであれば特に限定しないが、開気孔率を大
きくするには、焼結時間を短くするかまたは焼結温度を
低くすればよい。したがって焼結時間または焼結温度を
適宜調節して、20〜40容量％の開気孔率を有する予備焼
結体を得る。好ましい組成はAl2O3 70〜80重量％残りが
SiO2からなるムライト（理論組成Al2O3 71.8重量％、Si
O228.2重量％）を主とする焼結体である。開気孔率が40
容量％を超えると予備焼結体自体にクラックが発生する
場合があり、20容量％未満であると最終焼結体のクリス
トバライトの生成量が少なすぎてK1Cの改良が見られ
ず、いずれも好ましくない。好ましい開気孔率は20〜40
容量％である。The pre-sintered body used in the present invention is not particularly limited as long as it is manufactured according to a conventional method.To increase the open porosity, the sintering time must be shortened or the sintering temperature must be lowered. I just need. Therefore, the sintering time or sintering temperature is appropriately adjusted to obtain a pre-sintered body having an open porosity of 20 to 40% by volume. The preferred composition is 70-80% by weight of Al 2 O 3
Mullite consisting of SiO 2 (theoretical composition Al 2 O 3 71.8% by weight, Si
O 2 28.2% by weight). Open porosity of 40
May occur cracks exceeds vol% in the preliminary sintered body itself, showed no improvement with less than 20 volume% final sintered cristobalite K 1C by the amount is too small for both Not preferred. Preferred open porosity is 20-40
% By volume.
本発明において、SiO2前躯体を開気孔に充填する方法
としては、溶液含浸法、CVI法、溶融Si含浸法、Si上記
吸着法等など、セラミックス製造業界で慣用に行われて
いる方法が、またそれぞれの充填方法に適したSiO2前駆
体が採用される。例えば、溶液含浸法では、予備焼結体
をシリカゾル、シリコン、アルコキシドなどの適当な濃
度の溶液に浸漬すればよく、もし一回の浸漬で充填が十
分でなければ、浸漬−乾燥を繰り返せばよい。また、CV
I法では、SiCl4を原料として原焼結体の開気孔に金属シ
リコン状態で沈着させることによって充填する方法等が
示される。ここで使用されるSiO2前駆体とは、アニール
処理後においてクリストバライトとなる化合物である。
そのSiO2前駆体及び充填方法は開気孔の大きさなどを勘
案して適宜に採用する。In the present invention, as a method of filling the SiO 2 precursor into the open pores, a method commonly used in the ceramics manufacturing industry, such as a solution impregnation method, a CVI method, a molten Si impregnation method, and the above-described adsorption method of Si, An SiO 2 precursor suitable for each filling method is employed. For example, in the solution impregnation method, the pre-sintered body may be immersed in a solution of an appropriate concentration such as silica sol, silicon, or alkoxide, and if the filling is not sufficient in one immersion, immersion-drying may be repeated. . Also, CV
In the method I, a method is described in which SiCl 4 is used as a raw material to be deposited by depositing it in the open pores of a raw sintered body in a metallic silicon state. The SiO 2 precursor used here is a compound that becomes cristobalite after annealing.
The SiO 2 precursor and the filling method are appropriately adopted in consideration of the size of the open pores and the like.
SiO2前駆体を充填された予備焼結体は、必要に応じて
乾燥した後、1590〜1800℃で本焼結する。こうしてSiO2
前駆体はSiO2系ガラス相となる。上記の場合、常温から
昇温して本焼結温度に上げれば、前記乾燥工程は省略可
能である。The pre-sintered body filled with the SiO 2 precursor is dried if necessary, and then main-sintered at 1590 to 1800 ° C. Thus SiO 2
The precursor becomes a SiO 2 glass phase. In the above case, the drying step can be omitted if the temperature is raised from normal temperature to the main sintering temperature.
次いで、1450〜1580℃でアニール処理し、続いて急冷
することにより、表層のSiO2系ガラス相を安定なクリス
トバライトとして定着させる。アニール処理保持時間
は、開気孔の大きさ、特に深さと関連して一概には決め
られないが、48時間以上保持すれば、ほぼ目的は達せら
れる。なお、本焼結からアニール処理へ移行するさい、
焼結体を一旦冷却後アニール処理してもよく、また、温
度調節して連続的に行ってもよい。なお、好ましいアニ
ール処理温度は1500〜1550℃である。Next, annealing is performed at 1450 to 1580 ° C., followed by rapid cooling to fix the SiO 2 -based glass phase of the surface layer as stable cristobalite. The annealing treatment holding time cannot be unconditionally determined in relation to the size of the open pores, particularly the depth, but if the holding time is 48 hours or more, the purpose can be almost achieved. In addition, when shifting from the main sintering to the annealing process,
The sintered body may be once cooled and then annealed, or may be continuously adjusted to a desired temperature. The preferred annealing temperature is 1500 to 1550 ° C.
焼結、アニール処理をすることにより、SiO2前駆体は
SiO2系ガラス相を経由してクリストバライトとなる。予
備焼結体の組成がAl2O3過剰域のときは、開気孔中のSiO
2系ガラス相の一部は周辺のAl2O3と反応してムライトを
生成し、一方SiO2過剰域のときは、予備焼結体の表層マ
トリックス中に分散しているSiO2系ガラス相はクリスト
バライト化する。それゆえ、Al2O3過剰域、SiO2過剰域
いずれの場合においても、本発明は適用でき、特に後者
は著しく過剰になると高温温度を低下させるので好まし
くないが、SiO2が２重量％程度過剰の場合は、むしろK
1Cに好影響を与える。By sintering and annealing, the SiO 2 precursor becomes
It becomes cristobalite via the SiO 2 glass phase. When the composition of the pre-sintered body is in the Al 2 O 3 excess region, SiO 2 in the open pores
Part of the 2 system glass phase reacts with the surrounding Al 2 O 3 to form mullite, while in the SiO 2 excess region, the SiO 2 system glass phase dispersed in the surface matrix of the pre-sintered body Turns into cristobalite. Hence, Al 2 O 3 excess range, in either case SiO 2 excess region, the present invention is applicable, although not preferred because especially the latter lowers the hot temperature becomes a large excess, SiO 2 is about 2 wt% In excess, rather K
Has a positive effect on 1C .
以下、本発明を実施例に基づいて説明する。 Hereinafter, the present invention will be described based on examples.
試製予備焼結体を用いて下記要領で、ムライト質焼結
体を製造し、K1Cを測定した。In the following procedure using a Shisei presintered body, to produce a mullite sintered body was measured K 1C.
高純度ムライト粉末（AM−72S、日本セメント社製）
にα−Al2O3粉末（AL−160−SG−６昭和電工社製）を３
重量％配合し、バインダーを混合して、加圧成形し、脱
脂した後、1600℃、保持時間を変動させて予備焼結し
て、第１表に示す様々の開気孔率を有する予備焼結体を
作製した。High purity mullite powder (AM-72S, manufactured by Nippon Cement Co., Ltd.)
Α-Al 2 O 3 powder (AL-160-SG-6 manufactured by Showa Denko KK)
% By weight, mixed with a binder, press-molded, degreased, and pre-sintered at 1600 ° C with varying holding time to obtain a pre-sintering with various open porosity as shown in Table 1. The body was made.
各予備焼結体をSiO2含有量30重量％のシリカゾル（日
産化学工業社製「スノーテックスＳ」）に浸漬し、500
℃で乾燥してSiO2前駆体を予備焼結体に充填した。この
浸漬−乾燥工程の繰り返した。Each pre-sintered body was immersed in silica sol having 30% by weight of SiO 2 (“Snowtex S” manufactured by Nissan Chemical Industries, Ltd.), and 500
After drying at ℃, the pre-sintered body was filled with the SiO 2 precursor. This dipping-drying step was repeated.
引き続き、各予備焼結体について、電気炉で1630℃４
時間本焼結を行い、急冷した後、再び第１表に示す温度
で50時間アニール処理後、空冷した。Subsequently, each pre-sintered body was heated at 1630 ° C 4 in an electric furnace.
After performing main sintering for a period of time and quenching, annealing was performed again at the temperature shown in Table 1 for 50 hours, followed by air cooling.
急冷された本焼結体については、その一部を裁断した
試験片から薄片を作り、透過電子顕微鏡（TEM）による
電子線回折で各本焼結体の表層のSiO2系ガラス相の存非
を調べたところ、全てについて該ガラス相が確認され
た。With respect to the quenched sintered body, a thin section was prepared from a test piece obtained by cutting a part of the sinter, and the presence of the SiO 2 glass phase in the surface layer of each sintered body was determined by electron diffraction using a transmission electron microscope (TEM). As a result, the glass phase was confirmed for all the samples.
アニール処理後の焼結体についてＸ線回折を行い、ク
リストバライトが全ての焼結体に確認された。X-ray diffraction was performed on the sintered body after the annealing treatment, and cristobalite was confirmed in all the sintered bodies.
続いて、IM法でK1Cを測定し、得られた結果を第１表
併記した。Subsequently, K1C was measured by the IM method, and the obtained results are shown in Table 1.
なお、比較例１は予備焼結体について、上記本焼結を
行ったときの焼結体の開気孔率を示した。比較例５は本
焼結したさい、クラックが発生したので、SiO2系ガラス
相及びクリストバライトの確認ならびにK1Cの測定は行
わなかった。In Comparative Example 1, the open porosity of the pre-sintered body when the main sintering was performed was shown. In Comparative Example 5, cracks occurred during the main sintering, so that confirmation of the SiO 2 -based glass phase and cristobalite and measurement of K 1C were not performed.
〔発明の効果〕 本発明の方法によって得られるムライト質焼結体の破
壊靭性値は、従来法による複合焼結体のそれをはるかに
凌駕した。 [Effect of the Invention] The fracture toughness value of the mullite sintered body obtained by the method of the present invention far exceeds that of the composite sintered body according to the conventional method.
本発明の方法によって得られるムライト質焼結体を各
種部品に使用すれば、その部品のチッピングを大巾に減
少させることができる。When the mullite sintered body obtained by the method of the present invention is used for various parts, chipping of the parts can be greatly reduced.
Claims (1)
の予備焼結体の開気孔にSiO2前駆体を充填したのち、本
焼結し、得られた焼結体を1450〜1580℃でアニール処理
することにより、該焼結体の表層に存在するSiO2系ガラ
ス相をクリストバライト化することを特徴とするムライ
ト質焼結体の製造方法。1. A mullite pre-sintered body having an open porosity of 20 to 40% by volume is filled with an SiO 2 precursor in the open pores and then sintered to obtain a sintered body of 1450 to 1580. A method for producing a mullite sintered body, comprising annealing an SiO 2 -based glass phase present on the surface layer of the sintered body by cristobalite by annealing at a temperature of ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1204627A JP2757031B2 (en) | 1989-08-09 | 1989-08-09 | Method for producing mullite sintered body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1204627A JP2757031B2 (en) | 1989-08-09 | 1989-08-09 | Method for producing mullite sintered body |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0369577A JPH0369577A (en) | 1991-03-25 |
| JP2757031B2 true JP2757031B2 (en) | 1998-05-25 |
Family
ID=16493606
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1204627A Expired - Lifetime JP2757031B2 (en) | 1989-08-09 | 1989-08-09 | Method for producing mullite sintered body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2757031B2 (en) |
-
1989
- 1989-08-09 JP JP1204627A patent/JP2757031B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0369577A (en) | 1991-03-25 |
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