JP2001261431A - Chromia-zirconia sintered compact and its manufacturing method - Google Patents
Chromia-zirconia sintered compact and its manufacturing methodInfo
- Publication number
- JP2001261431A JP2001261431A JP2000085009A JP2000085009A JP2001261431A JP 2001261431 A JP2001261431 A JP 2001261431A JP 2000085009 A JP2000085009 A JP 2000085009A JP 2000085009 A JP2000085009 A JP 2000085009A JP 2001261431 A JP2001261431 A JP 2001261431A
- Authority
- JP
- Japan
- Prior art keywords
- chromia
- sintered body
- zirconia
- powder
- zirconia sintered
- 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.)
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Links
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ガラス溶解炉や廃
棄物処理溶融炉等の内張材に有用な緻密質のクロミア−
ジルコニア焼結体とその製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dense chromia useful as a lining material for a glass melting furnace or a waste treatment melting furnace.
The present invention relates to a zirconia sintered body and a method for producing the same.
【０００２】[0002]
【従来の技術】クロミア（Ｃｒ2Ｏ3）は、高温において
スラグ融液に濡れにくく溶解しにくいことから、クロミ
アを活用した焼結材料は、ガラス溶解炉や、一般及び産
業廃棄物等の減容化や無害化に有効な廃棄物処理用の溶
融炉等の内張炉材として広く用いられている。これらの
ガラス溶解炉及び廃棄物処理溶融炉では、通常、アルミ
ナ−クロミア質、アルミナ−ジルコニア−クロミア質耐
火物等が用いられているが、侵食が特に激しい部位に
は、その優れた耐食特性からクロミアを主体とした材料
が用いられている。例えば、一般に廃棄物処理溶融炉で
はガラス溶解炉に比べて侵食作用の高い融液が内張材と
接触するため、クロミアを多く含み、且つ、緻密性の高
い材料が必要とされている。 2. Description of the Related Art Chromia (Cr 2 O 3 ) is difficult to wet and dissolve in a slag melt at a high temperature. Therefore, a sintering material utilizing chromia is required to reduce a glass melting furnace, general and industrial waste, and the like. It is widely used as a lining furnace material such as a melting furnace for waste treatment that is effective for consolidation and detoxification. In these glass melting furnaces and waste treatment melting furnaces, alumina-chromia, alumina-zirconia-chromia refractories, etc. are generally used. A material mainly composed of chromia is used. For example, in general, in a waste treatment melting furnace, a melt having a higher erosion action is in contact with a lining material than a glass melting furnace, so that a material containing a large amount of chromia and having high density is required.
【０００３】これに対して、クロミアは大気中で焼成す
ると、蒸発−凝縮機構によって過度な粒成長を起こして
しまい、クロミア単成分では緻密に焼結することが困難
であることから、クロミアを主体とする耐火物を製造す
る場合には、通常、クロミアにＴｉＯ2や粘土等の焼結
助剤を添加し、大気中で高温焼成することで焼結の促進
が図られている。例えば、特開平６−３２１６２８号公
報には、ＴｉＯ2等の焼結助剤を用いて作られたクロミ
ア質焼結体を耐食性骨材として耐火物に応用することが
記載されている。On the other hand, when chromia is fired in the atmosphere, excessive grain growth occurs due to the evaporation-condensation mechanism, and it is difficult to sinter densely with a single chromia component. When a refractory is manufactured, sintering aids such as TiO 2 and clay are usually added to chromia, and sintering is promoted at a high temperature in the air to promote sintering. For example, JP-A-6-321628 describes that a chromia sintered body made by using a sintering aid such as TiO 2 is applied to a refractory as a corrosion-resistant aggregate.
【０００４】しかしながら、このような焼結体は空隙が
多く緻密性に劣り、更に、焼結助剤が液相としてクロミ
アの粒界に存在することとなるため、これがスラグ融液
と接触すると、スラグ中の特性成分の拡散によって焼結
体組織が著しく崩壊し、この結果、クロミアが本来有す
る優れた耐食性機能が生かされることなく、侵食が進行
してしまうことが生じる。However, such a sintered body has many voids and is inferior in density, and furthermore, a sintering aid is present as a liquid phase at the grain boundaries of chromia. The diffusion of the characteristic components in the slag significantly degrades the structure of the sintered body, and as a result, erosion proceeds without utilizing the excellent corrosion resistance function inherent in chromia.
【０００５】更に、クロミアは、他の材料に比べて熱膨
張係数が高く、急激な熱変化に対する耐性に劣り、いわ
ゆる熱衝撃抵抗性に劣るという欠点がある。そのため、
例えば、アルミナ−クロミア質焼結材料では未安定ジル
コニアを添加し、焼結過程で微細亀裂を形成させること
によって熱衝撃抵抗性の改善を図ることが行なわれてい
る（特開平６−１２２５４６号公報等参照）。しかしな
がら、一方で、未安定ジルコニアの場合に限らず、他の
成分との複合化は、焼結時の緻密化を更に困難なものと
し、この結果、クロミア質焼結体の耐食性を著しく低下
させてしまうという問題がある。以上のように、耐食性
と熱衝撃抵抗性を同時に満足したクロミア質焼結体を得
ることは非常に困難である。[0005] Furthermore, chromia has the disadvantage that it has a higher coefficient of thermal expansion than other materials, and is inferior in resistance to rapid thermal changes, and inferior in thermal shock resistance. for that reason,
For example, in an alumina-chromia sintered material, improvement of thermal shock resistance is performed by adding unstable zirconia and forming fine cracks in a sintering process (Japanese Patent Application Laid-Open No. 6-122546). Etc.). However, on the other hand, not only in the case of unstable zirconia, but also in combination with other components, the densification during sintering becomes more difficult, and as a result, the corrosion resistance of the chromia sintered body is significantly reduced. Problem. As described above, it is very difficult to obtain a chromia sintered body that simultaneously satisfies corrosion resistance and thermal shock resistance.
【０００６】これに対し、ガラス溶解炉においては勿論
のこと、特に、上記の廃棄物処理溶融炉では、内張材の
耐用向上によって安定的な連続操業を実現することが望
まれている。これらの溶融炉に使用される内張材として
は、高温での侵食作用に耐えられる耐食性材料であると
共に、急激な温度変化にも対応できる熱衝撃抵抗性に優
れる材料であることが要求される。このため、工業的規
模で、耐食性と熱衝撃抵抗性とを同時に満足した有用な
クロミア質焼結体の開発が待望されている。On the other hand, not only in the glass melting furnace, but particularly in the above waste treatment melting furnace, it is desired to realize stable continuous operation by improving the durability of the lining material. The lining material used in these melting furnaces is required to be not only a corrosion-resistant material that can withstand erosion at high temperatures, but also a material that has excellent thermal shock resistance that can cope with rapid temperature changes. . For this reason, development of a useful chromia sintered body that simultaneously satisfies corrosion resistance and thermal shock resistance on an industrial scale has been desired.
【０００７】[0007]
【発明が解決しようとする課題】従って、本発明の目的
は、クロミアの本来の特性である優れた耐食性機能を充
分に活用しつつ熱衝撃抵抗性の改善が図られた、ガラス
溶解炉だけでなく廃棄物処理溶融炉等の耐食性材料とし
ても適用可能で、しかも、これらの溶融炉を、長期間に
わたって安定的に連続操業できるクロミア−ジルコニア
焼結体、及び、かかる優れた特性のクロミア質焼結体が
容易に得られるクロミア−ジルコニア焼結体の製造方法
を提供することにある。SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide only a glass melting furnace which is capable of improving thermal shock resistance while fully utilizing the excellent corrosion resistance function, which is the original property of chromia. Chromia-zirconia sintered body that can be continuously operated for a long period of time, and can be used as a corrosion-resistant material such as a waste treatment melting furnace. An object of the present invention is to provide a method for producing a chromia-zirconia sintered body from which a compact can be easily obtained.
【０００８】[0008]
【課題を解決するための手段】上記の目的は、下記の本
発明によって達成される。即ち、本発明は、相対密度が
９７％以上の緻密な組織を有し、且つ、クロミア粒子か
らなる組織中に重量平均粒子径１０〜８０μｍのジルコ
ニア粒子が全体に対して０．１〜１５重量％の割合で均
一に分散されていることを特徴とするクロミア−ジルコ
ニア焼結体、及び、上記クロミア−ジルコニア焼結体を
製造するための製造方法であって、クロミア粉体に重量
平均粒子径１０〜８０μｍのジルコニア粉体を粉体原料
の全量に対して０．１〜１５重量％になるように加えて
均一に分散させて混合粉体とし、該混合粉体を真空中若
しくは不活性雰囲気中で加圧しながらパルス通電加熱し
て成形及び焼成することを特徴とするクロミア−ジルコ
ニア焼結体の製造方法である。The above objects are achieved by the present invention described below. That is, the present invention has a dense structure having a relative density of 97% or more, and zirconia particles having a weight average particle diameter of 10 to 80 μm are contained in a structure composed of chromia particles in an amount of 0.1 to 15 wt. % And a production method for producing the chromia-zirconia sintered body, wherein the chromia powder has a weight average particle size A zirconia powder of 10 to 80 μm is added in an amount of 0.1 to 15% by weight based on the total amount of the powder raw material and uniformly dispersed to obtain a mixed powder, and the mixed powder is placed in a vacuum or in an inert atmosphere. This is a method for producing a chromia-zirconia sintered body, characterized in that pulsed electric heating is performed while applying pressure and molding and firing are performed.
【０００９】[0009]
【発明の実施の形態】以下に、好ましい実施の形態を挙
げて、本発明を詳細に説明する。本発明のクロミア−ジ
ルコニア焼結体は、クロミア粒子からなる焼結組織中
に、重量平均粒子径１０〜８０μｍのジルコニア粒子が
全体に対して０．１〜１５重量％の割合で均一に分散さ
れた相対密度が９７％以上の緻密な形態を有することを
特徴とする。より好ましくは、クロミア粒子からなる組
織中に重量平均粒子径２０〜４５μｍのジルコニア粒子
が１〜９重量％の割合で均一に分散されている構成のク
ロミア−ジルコニア焼結体、更には、焼結体の組織を構
成する母材であるクロミア粒子の平均粒子径が１〜３μ
ｍの範囲にあるクロミア−ジルコニア焼結体である。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to preferred embodiments. In the chromia-zirconia sintered body of the present invention, zirconia particles having a weight average particle diameter of 10 to 80 μm are uniformly dispersed in a sintered structure composed of chromia particles at a ratio of 0.1 to 15% by weight based on the whole. Characterized by having a dense form having a relative density of 97% or more. More preferably, a chromia-zirconia sintered body having a structure in which zirconia particles having a weight average particle diameter of 20 to 45 μm are uniformly dispersed at a ratio of 1 to 9% by weight in a structure composed of chromia particles, The average particle size of the chromia particles as the base material constituting the body tissue is 1 to 3 μm.
m is a chromia-zirconia sintered body in the range of m.
【００１０】かかる構成の本発明のクロミア−ジルコニ
ア焼結体は、電子顕微鏡（ＳＥＭ）による観察で示され
ているように、クロミア粒子からなる焼結体の組織内
に、該クロミア粒子よりも粒径の大きいジルコニア粒子
が均一に分散されており、該ジルコニア粒子の周囲のク
ロミア焼結組織中に微細な空隙が存在し、更にその空隙
からクロミア焼結組織に伸展した微細な亀裂が存在して
いる。そして、焼結体の大部分を占めるクロミアで構成
されている部分は、局所的な粒成長のない粒子径の揃っ
た均質な焼結組織が緻密に形成された状態となっている
（図１参照）。このように、本発明のクロミア−ジルコ
ニア焼結体は、全体として緻密なクロミア組織を有する
一方で、その焼結組織中に空隙及び／又は微細な亀裂が
均一な分散状態で存在する構造を有するものであるた
め、クロミアが本来有している耐食性が損なわることな
くその作用が充分に発現され、しかも、熱衝撃抵抗性に
優れたクロミア質焼結体となる。かかる効果は、緻密な
クロミア組織によって耐食性が実現され、クロミア焼結
組織内に存在する空隙及び／又は微細な亀裂によって、
熱衝撃により加わる内部応力が緩和される結果、熱衝撃
抵抗性が実現されたものと考えている。[0010] The chromia-zirconia sintered body of the present invention having the above-described structure has a smaller particle size than the chromia particles in the structure of the sintered body composed of chromia particles, as shown by observation with an electron microscope (SEM). Large diameter zirconia particles are uniformly dispersed, fine voids are present in the chromia sintered structure around the zirconia particles, and fine cracks extending from the voids to the chromia sintered structure are present. I have. The portion composed of chromia, which occupies most of the sintered body, is in a state in which a homogeneous sintered structure having a uniform particle size without local grain growth is densely formed (FIG. 1). reference). As described above, the chromia-zirconia sintered body of the present invention has a structure in which voids and / or fine cracks are present in a uniformly dispersed state in the sintered structure while having a dense chromia structure as a whole. Therefore, the chromia sintered body exhibits a sufficient effect without impairing the inherent corrosion resistance of chromia, and has excellent thermal shock resistance. This effect is achieved by the corrosion resistance achieved by the dense chromia structure, and by the voids and / or fine cracks existing in the chromia sintered structure.
We believe that thermal shock resistance was achieved as a result of the relaxation of the internal stress applied by the thermal shock.
【００１１】上記のような構造を有するクロミア−ジル
コニア焼結体を容易に得ることのできる本発明のクロミ
ア−ジルコニア焼結体の製造方法について説明する。本
発明のクロミア−ジルコニア焼結体の製造方法では、先
ず、出発原料として、クロミア粉体と、粉体原料の全体
に対して０．１〜１５重量％、好ましくは１〜９重量％
となる範囲で、特定の粒径を有するジルコニア粉体を混
合させた混合粉体を調製する。そして、この混合粉体
を、真空中又は不活性雰囲気中で加圧しながらパルス通
電加熱することで、成形と同時に焼成がなされてクロミ
ア−ジルコニア焼結体が得られる。かかる方法によれ
ば、相対密度が９７％以上と緻密なクロミア組織をも
ち、且つ、該クロミア焼結組織中に均一に分散されたジ
ルコニア粒子の周辺に空隙及び／又は微細な亀裂を有す
る、耐食性と熱衝撃抵抗性とを実現し得る本発明のクロ
ミア−ジルコニア焼結体が容易に得られる。A method for producing a chromia-zirconia sintered body of the present invention, which can easily obtain a chromia-zirconia sintered body having the above structure, will be described. In the method for producing a chromia-zirconia sintered body of the present invention, first, chromia powder is used as a starting material, and 0.1 to 15% by weight, preferably 1 to 9% by weight, based on the entire powder material.
A mixed powder is prepared by mixing zirconia powder having a specific particle size within the range described below. Then, the mixed powder is heated by applying a pulse current while applying a pressure in a vacuum or an inert atmosphere, whereby sintering is performed simultaneously with molding, and a chromia-zirconia sintered body is obtained. According to this method, the corrosion resistance has a dense chromia structure with a relative density of 97% or more, and has voids and / or fine cracks around zirconia particles uniformly dispersed in the chromia sintered structure. The chromia-zirconia sintered body of the present invention which can realize the thermal shock resistance and the thermal shock resistance can be easily obtained.
【００１２】上記の製造方法で母材原料として使用する
クロミア粉体は、得られるクロミア焼結体の相対密度が
９７％以上であることを要するため、特に、純度の高い
ものを使用することが好ましい。例えば、９９．５重量
％以上の純度の粉体を用いることが好ましい。このよう
な純度の市販されているクロミア粉体は、通常、平均粒
径が１〜３μｍの範囲に調製されているが、本発明にお
いては、これをそのまま使用することができる。本発明
の製造方法によれば、粒成長が抑制されるため、このよ
うなクロミア粉体を使用すれば、１〜３μｍの粒子がそ
のまま焼結した緻密な組織を有するクロミア質焼結体が
得られる。より均質な焼結体を得るためには、よりシャ
ープな粒度分布を有する均一なクロミア微粉体を原料と
して用いることが好ましい。The chromia powder used as a base material in the above-mentioned production method requires that the relative density of the obtained chromia sintered body be 97% or more. preferable. For example, it is preferable to use powder having a purity of 99.5% by weight or more. Commercially available chromia powder having such a purity is usually prepared to have an average particle size in the range of 1 to 3 μm, but in the present invention, this can be used as it is. According to the production method of the present invention, since grain growth is suppressed, use of such chromia powder provides a chromia sintered body having a dense structure in which particles of 1 to 3 μm are sintered as they are. Can be In order to obtain a more uniform sintered body, it is preferable to use a uniform chromia fine powder having a sharper particle size distribution as a raw material.
【００１３】上記のクロミア粉体に添加混合して用いる
ジルコニア粉体は、ＣａＯ乃至はＹ 2Ｏ3で安定化され
た、重量平均粒子径が１０〜８０μｍ、より好ましく
は、２０〜４５μｍの大きさの微粒子を使用する。即
ち、本発明において、粒子径が８０μｍよりも大きいジ
ルコニア粉体を用いた場合には粉体原料の充填性が損な
われ、母材であるクロミア粉体の焼結が阻害され、焼結
体の緻密化が達成されなくなる。更に、焼結条件等によ
っては、４５μｍよりも大きいジルコニア粉体を原料と
して用いた場合に、焼結体の緻密化が充分とはいえない
ことが生じるため、粒子径が４５μｍ以下の大きさのジ
ルコニア微粒子を原料として使用することがより好まし
い。[0013] The above chromia powder is added and mixed for use.
Zirconia powder is CaO or Y TwoOThreeIs stabilized by
In addition, the weight average particle diameter is more preferably from 10 to 80 μm.
Uses fine particles having a size of 20 to 45 μm. Immediately
In the present invention, particles having a particle diameter larger than 80 μm are used.
When luconia powder is used, the filling property of the powder raw material is impaired.
The sintering of chromia powder, which is the base material, is
Body densification is no longer achieved. Furthermore, depending on the sintering conditions, etc.
Zirconia powder larger than 45 μm
When used, the densification of the sintered body is not sufficient
May occur, so that a particle having a particle size of 45 μm or less
It is more preferable to use luconia fine particles as raw material
No.
【００１４】一方、使用するジルコニア粉体の重量平均
粒子径が１０μｍよりも小さいと、クロミア焼結体中に
ジルコニア粉体を添加しても焼結過程で微細亀裂を形成
することができず、焼結体に熱衝撃抵抗性を発現させる
ことができない。更に、２０μｍよりも小さい粒径のジ
ルコニア粉体を用いた場合においても、熱衝撃抵抗性向
上の効果が充分に得られないことがあるので、焼結の際
に、良好な状態でクロミア焼結組織中に空隙及び微細亀
裂を形成させるためには、２０μｍ以上の粒径のジルコ
ニア粉体を用いることがより好適である。On the other hand, if the weight average particle diameter of the zirconia powder used is smaller than 10 μm, even if the zirconia powder is added to the chromia sintered body, fine cracks cannot be formed in the sintering process, The sintered body cannot exhibit thermal shock resistance. Furthermore, even when zirconia powder having a particle size smaller than 20 μm is used, the effect of improving thermal shock resistance may not be sufficiently obtained. In order to form voids and fine cracks in the structure, it is more preferable to use zirconia powder having a particle size of 20 μm or more.
【００１５】原料となる混合粉体中における上記のよう
な粒径を有するジルコニア粉体の添加量は、全体に対し
て０．１〜１５重量％、更には、１〜９重量％とするこ
とが好ましい。１５重量％を超えると、混合粉体中にジ
ルコニア粉体を均一分散することが困難となり、焼結体
とした場合に緻密化が達成されなくなり、一方、０．１
重量％よりも少ないと、ジルコニア粉体添加の効果が得
られない。焼結体組織中におけるジルコニア粒子の均一
な分散をより確実なものとし、得られる焼結体の緻密化
の状態をより好適なものとするためには、ジルコニア粉
体の割合を原料粉体全体の９重量％以下とすることが好
ましい。The amount of the zirconia powder having the above-mentioned particle size in the mixed powder as a raw material is 0.1 to 15% by weight, and more preferably 1 to 9% by weight based on the whole. Is preferred. If the content exceeds 15% by weight, it is difficult to uniformly disperse the zirconia powder in the mixed powder, and when a sintered body is used, densification cannot be achieved.
If the amount is less than 10% by weight, the effect of adding zirconia powder cannot be obtained. In order to ensure uniform dispersion of the zirconia particles in the sintered body structure and to make the state of densification of the obtained sintered body more suitable, the proportion of the zirconia powder should be adjusted to the entire raw material powder. Is preferably 9% by weight or less.
【００１６】本発明においては、上記のような性状のク
ロミア粉体とジルコニア粉体とを特定の割合で混合した
混合粉体を焼結体原料とし、従来のように予め成形体を
作成することなくそのまま使用することができるが、こ
の際に、原料中におけるジルコニア粉体の凝集又は偏在
を避け、前述したような良好な組織構造を有する焼結体
を確実に得るためには、粉体原料中にエタノール等の溶
媒を加え、ボールミル等によって湿式分散混合させて、
均質な混合粉体としたものを用いることが望ましい。In the present invention, a mixed powder obtained by mixing a chromia powder and a zirconia powder having the above properties at a specific ratio is used as a raw material for a sintered body, and a molded body is prepared in advance as in the prior art. However, in this case, in order to avoid agglomeration or uneven distribution of the zirconia powder in the raw material and to obtain a sintered body having a favorable structure as described above, the powder raw material must be used. A solvent such as ethanol is added into the mixture, and the mixture is wet-dispersed and mixed by a ball mill or the like.
It is desirable to use a homogeneous mixed powder.
【００１７】本発明のクロミア−ジルコニア焼結体の製
造方法においては、上記のようにして調製したクロミア
粉体とジルコニア粉体との均質な混合粉体を、真空中若
しくは不活性雰囲気中で加圧しながらパルス通電加熱し
て成形及び焼成する。即ち、本発明の製造方法によれ
ば、従来行なわれていたように予め成形体を作成すると
いった工程を経ることなく、粉体原料をそのまま用いて
クロミア質耐火物が得られるという製造上の大きな利点
がある。In the method for producing a chromia-zirconia sintered body of the present invention, a homogeneous mixed powder of the chromia powder and the zirconia powder prepared as described above is added in a vacuum or in an inert atmosphere. Forming and baking by pulse current heating while pressing. That is, according to the production method of the present invention, a chromia-based refractory can be obtained using powder raw materials as they are, without going through a step of preparing a compact in advance as conventionally performed. There are advantages.
【００１８】本発明において使用するパルス通電加熱加
圧焼結法としては、パルス電流を直接又は間接に利用す
る方法、或いは直接と間接を同時に行なう方法等、各種
の方法があるが、いずれも利用できる。パルス通電加熱
加圧焼結法では、グラファイト等の材料からなる導電性
焼成型（ダイ）に充填された粉体に上下のパンチによっ
て一軸加圧しながら、パルス電流を粉体及び導電性ダイ
に流すことによって起こる粉体自身の発熱作用と、ダイ
及び上下のパンチから伝わるジュール熱で焼成を行な
う。通電するパルスとしては、例えば、正弦波交流の半
波（例えば、正弦波交流を半波整流して得られるもの）
を用い、このパルスを所定回数印加後、所定回数休止す
ることを繰り返し行なう。本発明において使用する加圧
方法としては、上記のような粉体原料に対して一軸加圧
する方法に限定されず、一軸加圧を行ないながら、チャ
ンバー内に導入した不活性ガスを利用した全体加圧によ
って行なってもよい。以下、加圧焼成の方法について具
体的に説明する。As the pulse current heating and pressurizing sintering method used in the present invention, there are various methods such as a method of using a pulse current directly or indirectly, and a method of simultaneously performing the direct and indirect methods. it can. In the pulse current heating and pressure sintering method, a pulse current is applied to the powder and the conductive die while uniaxially pressing the powder filled in a conductive firing mold (die) made of a material such as graphite by upper and lower punches. The baking is performed by the heat generated by the powder itself and Joule heat transmitted from the die and the upper and lower punches. The energizing pulse may be, for example, a half-wave of a sine wave AC (for example, a half-wave rectified sine wave AC).
, The pulse is applied a predetermined number of times, and then a predetermined number of pauses is repeatedly performed. The pressurization method used in the present invention is not limited to the above-mentioned method of uniaxially pressurizing the powder raw material, and the entire process using the inert gas introduced into the chamber while performing the uniaxial pressurization. It may be performed by pressure. Hereinafter, the pressure firing method will be specifically described.
【００１９】上記のようなパルス通電加熱加圧焼結法で
焼結する場合の焼成条件について説明する。先ず、本発
明においては、真空中、又は、クロミア及びジルコニア
に対して不活性な雰囲気中で焼成を行なうが、この際、
いずれの不活性ガスを使用することもできる。不活性ガ
スの中では、アルゴンガス雰囲気中で行うのが一般的で
ある。The sintering conditions for sintering by the above-described pulse current heating / pressure sintering method will be described. First, in the present invention, firing is performed in a vacuum or in an atmosphere inert to chromia and zirconia.
Any inert gas can be used. In general, the inert gas is used in an argon gas atmosphere.
【００２０】更に、本発明においては、焼成温度１２０
０〜１６００℃、荷重１０〜６０ＭＰａの範囲、更に好
ましくは、１４００〜１５００℃、荷重２０〜４０ＭＰ
ａで焼成を行なうことが好ましい。実際の焼成条件は、
温度と荷重との兼ね合いにおいて決定されるので、上記
の範囲内から適宜に焼成条件を決定すればよい。例え
ば、より高い温度で焼成すれば圧力を低く抑えることが
でき、圧力を高くすることによって、より低い温度での
焼成が可能となる。Further, in the present invention, the sintering temperature is set to 120.
0 to 1600 ° C, load 10 to 60MPa, more preferably 1400 to 1500 ° C, load 20 to 40MPa
It is preferable to perform calcination at a. The actual firing conditions are
Since the firing conditions are determined based on the balance between the temperature and the load, the firing conditions may be appropriately determined from the above range. For example, if the firing is performed at a higher temperature, the pressure can be kept low, and the firing can be performed at a lower temperature by increasing the pressure.
【００２１】特に、高い相対密度の焼結体を得るために
は、１４００℃以上の焼成温度で焼成することが望まし
い。又、焼成温度が高過ぎると、経済性に劣り、粒子の
成長が著しくなり、焼結体の強度の低下を招く恐れがあ
るため、１６００℃、好ましくは１５００℃を超えない
温度で焼成することが望ましい。加圧力については、荷
重１０〜６０ＭＰａの範囲で加圧することが好ましい
が、特に、４０ＭＰａよりも大きい圧力をかけたとして
も、焼結性に対する加圧効果の著しい向上が得られ難い
ため、経済性との兼ね合いから加圧力は４０ＭＰａであ
れば充分である。一方、２０ＭＰａよりも加圧力が小さ
いと、場合によっては加圧効果が充分に得られないこと
があるので実用的でない。In particular, in order to obtain a sintered body having a high relative density, it is desirable to fire at a firing temperature of 1400 ° C. or more. On the other hand, if the firing temperature is too high, the economy is inferior, the growth of particles becomes remarkable, and the strength of the sintered body may be reduced. Therefore, firing at a temperature not exceeding 1600 ° C., preferably 1500 ° C. Is desirable. As for the pressing force, it is preferable to apply a pressure in the range of a load of 10 to 60 MPa. In particular, even if a pressure greater than 40 MPa is applied, a remarkable improvement in the pressing effect on the sinterability is difficult to obtain, so that economic efficiency is low. In view of the above, it is sufficient that the pressure is 40 MPa. On the other hand, if the pressing force is smaller than 20 MPa, the pressurizing effect may not be sufficiently obtained in some cases, so that it is not practical.
【００２２】従って、本発明において、より良好な性状
を有する９７％以上の高い相対密度の本発明のクロミア
−ジルコニア焼結体が得られ、しかも、より実用的な焼
成条件としては、焼成温度が１４００〜１５００℃、荷
重が２０〜４０ＭＰａの範囲で焼成を行なうとよい。か
かる条件で焼成を行なえば、焼結体の組織が緻密で、ス
ラグ融液と接触したとしても組織が崩壊することがな
く、クロミアのもつ優れた耐食性機能が有効に生かさ
れ、しかも、ジルコニア粉体の添加によって熱衝撃抵抗
性の発現に有効な微細亀裂がクロミア焼結組織中に形成
された状態の焼結体が、容易に、且つ、安定して得られ
る。Therefore, in the present invention, a chromia-zirconia sintered body of the present invention having better properties and a high relative density of 97% or more can be obtained, and more practical firing conditions include a firing temperature of It is preferable to perform firing at 1400 to 1500 ° C. and a load of 20 to 40 MPa. If sintering is performed under such conditions, the structure of the sintered body is dense, the structure does not collapse even if it comes into contact with the slag melt, the excellent corrosion resistance function of chromia is effectively utilized, and the zirconia powder By adding the body, a sintered body in which fine cracks effective for the development of thermal shock resistance are formed in the chromia sintered structure can be easily and stably obtained.
【００２３】本発明者らの検討によれば、本発明のクロ
ミア−ジルコニア焼結体のように、特定の粒径を有する
ジルコニア粉体が、特定の範囲内の添加量でクロミア粉
体原料中に均一に分散されている場合には、母材である
クロミアとの熱膨張係数の違いから、その焼結過程にお
いて、ジルコニア粒子の粒界に微細な亀裂及び／又は空
孔が均質な状態で形成されたクロミア焼結体となること
がわかった。そして、焼結体組織内に均一に存在するこ
のような微細亀裂及び／又は空孔によって、急激な熱衝
撃によって発生する亀裂を偏向させるか、その伸展を阻
害することで内部応力を緩和させることができ、この結
果、焼結体の熱衝撃抵抗性を向上させるという作用が発
現される。更に、クロミア母材に添加して使用するジル
コニアは高融点であり、更に高温においてＳｉＯ2質ス
ラグ等に溶解しにくいため、本発明における添加量の範
囲内であれば、従来の焼結助剤のように、液相としてク
ロミアの粒界に存在するといったことにはならないた
め、クロミアが本来有する耐食性機能が損なわることは
なく、耐食性に優れる焼結体となる。According to the study of the present inventors, zirconia powder having a specific particle size, such as the chromia-zirconia sintered body of the present invention, is contained in the chromia powder raw material at an added amount within a specific range. When the zirconia particles are uniformly dispersed in the zirconia particles during the sintering process, fine cracks and / or pores are formed in a homogeneous state due to the difference in the coefficient of thermal expansion from the base material chromia. It was found that the formed chromia sintered body was obtained. Then, such fine cracks and / or pores uniformly present in the structure of the sintered body deflect the cracks generated by the rapid thermal shock or reduce the internal stress by inhibiting the extension. As a result, the effect of improving the thermal shock resistance of the sintered body is exhibited. Further, zirconia used by being added to the chromia base material has a high melting point and is hardly dissolved in SiO 2 slag or the like at a high temperature. As described above, the chromia does not exist as a liquid phase at the grain boundary of chromia, so that the corrosion resistance function inherent to chromia is not impaired, and a sintered body having excellent corrosion resistance is obtained.
【００２４】更に、本発明のクロミア−ジルコニア焼結
体の製造方法は、適正な範囲の粒子径を有するジルコニ
アを、クロミアに対して特定の割合で用いることで、結
晶変態のない安定化ジルコニアを使用した場合でも粒界
に微細亀裂や空隙を良好な状態で生じさせることができ
るので、熱衝撃抵抗性の改善のために使用するジルコニ
ア原料の種類が限定されず、原料選択の範囲が広いとい
う製造上の大きな利点もある。Further, the method for producing a chromia-zirconia sintered body according to the present invention is characterized in that zirconia having a particle size in an appropriate range is used in a specific ratio to chromia, whereby stabilized zirconia having no crystal transformation is obtained. Even when used, fine cracks and voids can be formed in the grain boundary in a good state, so the type of zirconia raw material used for improving thermal shock resistance is not limited, and the range of raw material selection is wide There are also significant manufacturing advantages.
【００２５】次に、本発明のクロミア−ジルコニア焼結
体の製造方法で用いるパルス通電加熱加圧焼結法の効果
について説明する。パルス通電加熱加圧焼結法では、先
に述べたように、黒鉛等の導電性ダイスに充填された粉
体原料に荷重をかけながら加熱を行うため、粉体の塑性
流動が起き易く、空隙が効果的に排除され、より緻密な
焼結体が得られる。更に、パルス通電加熱加圧焼結法の
プロセスでは、外部応力のかかる粒子接触部に高エネル
ギーのパルス電流が流れ、溶着状態のネックを瞬時に形
成するものであるため、従来のホットプレス法、熱間等
方加圧焼結法に比べて、短時間での焼結が可能となる。
更に、その結果として、先に述べたクロミアの性質であ
る粒成長を抑制することが可能となり、焼結の際に粒成
長を伴うことがないので焼結体組織を緻密化できるとい
う利点もある。Next, the effect of the pulse current heating / pressurizing sintering method used in the method for producing a chromia-zirconia sintered body of the present invention will be described. In the pulse current heating and pressure sintering method, as described above, since heating is performed while applying a load to the powder raw material filled in a conductive die such as graphite, the plastic flow of the powder is likely to occur, and the void is easily generated. Is effectively eliminated, and a denser sintered body can be obtained. Furthermore, in the process of the pulse current heating and pressure sintering method, a high-energy pulse current flows in the particle contact portion where external stress is applied, and a neck in a welded state is instantaneously formed. Sintering can be performed in a shorter time as compared with the hot isostatic pressing method.
Furthermore, as a result, it is possible to suppress the grain growth, which is a property of chromia described above, and there is also an advantage that the sintered body structure can be densified because the sintering does not involve the grain growth. .
【００２６】以上のパルス通電加熱加圧焼結法を用いた
プロセスにより得られた本発明のクロミア−ジルコニア
焼結体を電子顕微鏡（ＳＥＭ）によって観察した結果、
図１に示したように、クロミアに比べて格段に大きな粒
径のジルコニア粒子の周囲に空隙が存在し、更にその空
隙からクロミア焼結組織に伸展した微細な亀裂が存在し
ていることが確認できた。又、クロミアで構成された部
分については、局所的な粒成長が起きることなく、粒子
径の揃った均質な焼結組織が形成されていることがわか
った。パルス通電加熱加圧焼結法を用いれば、これらの
特徴を有する、従来法のものと比べて高温耐食性材料と
しての信頼性の高い本発明のクロミア−ジルコニア焼結
体が容易に得られる。更に、本発明のクロミア−ジルコ
ニア焼結体の製造方法は、成形と焼成が同時に行われ、
更に、僅か５分程度の保持時間で焼結処理を行うことが
できるため、工業的規模での生産に利用することが可能
である。As a result of observing the chromia-zirconia sintered body of the present invention obtained by the above-described process using the pulse current heating / pressure sintering method by an electron microscope (SEM),
As shown in FIG. 1, it was confirmed that voids exist around zirconia particles having a significantly larger particle size than chromia, and that fine cracks extending from the voids to the chromia sintered structure exist. did it. In addition, it was found that a uniform sintered structure having a uniform particle size was formed without local grain growth in the portion composed of chromia. The use of the pulse current heating / pressurizing sintering method makes it possible to easily obtain the chromia-zirconia sintered body of the present invention having these features and having higher reliability as a high-temperature corrosion-resistant material than the conventional method. Furthermore, in the method for producing a chromia-zirconia sintered body of the present invention, molding and firing are performed simultaneously,
Furthermore, since the sintering process can be performed with a holding time of only about 5 minutes, it can be used for production on an industrial scale.
【００２７】[0027]
【実施例】次に、実施例及び比較例を挙げて本発明を更
に詳細に説明する。 ＜実施例１〜４及び参考例１＞クロミア粉体原料として
平均粒径１μｍの市販品（日本化学工業(株)製、Ｇ５）
を用い、ジルコニア粉体原料として平均粒径４４μｍの
市販品（福島製鋼(株)製、ジルボン）を用いた。そし
て、これらをポットミルを用いて下記の方法で混合して
混合粉体原料を調製した。ポットミルによる混合は、
１，０００ｍｌポリプロピレン容器に混合粉体３５０ｇ
（クロミア粉体を３４６．５ｇ、ジルコニア粉体を３．
５ｇで全体に対してジルコニアを１重量％含有）、エタ
ノールを３００ｍｌ、φ１０ｍｍの鉄芯入りナイロン樹
脂ボールを３００個入れ、６０ｒ.ｐ.ｍ.の回転数で２
４時間行った。上記のようにして混合した後、ロータリ
ーエバポレーターを用いて乾燥を行い、その後、目の開
きが３００μｍのフルイで分級して、３００μｍ以下の
混合粉体を得た。Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. <Examples 1 to 4 and Reference Example 1> Commercially available chromia powder raw material having an average particle diameter of 1 µm (G5, manufactured by Nippon Chemical Industry Co., Ltd.)
And a commercial product (Zirbon, manufactured by Fukushima Steel Co., Ltd.) having an average particle size of 44 μm was used as a zirconia powder raw material. These were mixed using a pot mill by the following method to prepare a mixed powder raw material. Mixing with a pot mill
350g of mixed powder in a 1,000ml polypropylene container
(346.5 g of chromia powder and 3.6.5 g of zirconia powder).
5 g, containing 1% by weight of zirconia with respect to the whole), 300 ml of ethanol, 300 pieces of nylon resin balls containing a 10 mm iron core, and 2 at a rotation speed of 60 rpm.
Performed for 4 hours. After mixing as described above, the mixture was dried using a rotary evaporator, and then classified with a sieve having openings of 300 μm to obtain a mixed powder of 300 μm or less.
【００２８】粉体の充填部は、図２に示したように、上
下パンチとダイとによって形成されるが、パンチの形状
は上下ともにφ６０×４０ｍｍであり、ダイの形状は、
外径φ１００ｍｍ、内径φ６０．８ｍｍ、高さ７０ｍｍ
のものを用いた。これらの材質はいずれもグラファイト
である。先ず、ダイに下パンチを差し込んだ後、ダイ内
部に、上記で調製した混合粉体原料を均一に充填し、上
パンチを差し込んだ。本実施例では、ダイ及びパンチ
と、粉体との反応によるダイの損傷を防ぐために、０．
２ｍｍ厚のカーボンシートを、上下パンチと充填された
混合粉体原料との間に各々１枚、粉体原料が充填される
ダイの内壁に２枚設置した。The filling portion of the powder is formed by upper and lower punches and a die as shown in FIG. 2, and the shape of the punch is φ60 × 40 mm at both upper and lower sides, and the shape of the die is
Outer diameter φ100mm, inner diameter φ60.8mm, height 70mm
Was used. These materials are all graphite. First, after inserting the lower punch into the die, the mixed powder raw material prepared above was uniformly filled into the die, and the upper punch was inserted. In this embodiment, in order to prevent the die from being damaged due to the reaction between the die and the punch and the powder, the diameter of the die is set to 0.
One 2 mm-thick carbon sheet was placed between the upper and lower punches and the filled mixed powder material, and two sheets were placed on the inner wall of the die filled with the powder material.
【００２９】次に、上記のようにしてクロミア−ジルコ
ニア混合粉体原料を充填したダイスを、放電プラズマ焼
結機（（株）イズミテック製、ＳＰＳ−７．４０）のチ
ャンバー内にセットし、焼成を行った。本実施例におけ
る通電パルスは、正弦波交流を整流して得られたパルス
幅２．７ｍｓの半波を用い、このパルスを１２回オンし
て印加した後、２回オフして休止（ゼロ電流値の幅が
５．４ｍｓ）することを繰り返し行なった。先ず、チャ
ンバー内を５Ｐａ以下の真空状態とした後、表１に示し
たような種々の焼成条件で焼成して、Ｎｏ．Ａ〜Ｅの５
種類の焼結体を得た。即ち、焼成条件は、夫々、３０又
は４０ＭＰａの加圧力を粉体にかけながら、１９又は２
０分間で１３５０、１４００、１４５０℃の到達温度に
夫々昇温し、その所定の温度で５分間保持して加圧焼成
を行なった。このようにして焼成した後、加圧を完全に
開放すると共に自然冷却し、４００℃に達した時点で大
気開放して各焼結体を得た。Next, the die filled with the chromia-zirconia mixed powder material as described above is set in a chamber of a discharge plasma sintering machine (SPS-7.40, manufactured by Izmitek Co., Ltd.) The firing was performed. The energizing pulse in this embodiment uses a half-wave of 2.7 ms in pulse width obtained by rectifying a sine wave alternating current. This pulse is turned on and applied 12 times, then turned off twice and stopped (zero current). The value range was 5.4 ms). First, the interior of the chamber was evacuated to 5 Pa or less, and then fired under various firing conditions as shown in Table 1. 5 of A to E
Various types of sintered bodies were obtained. That is, the sintering conditions were 19 or 2 while applying a pressing force of 30 or 40 MPa to the powder, respectively.
The temperature was raised to the ultimate temperature of 1350, 1400, or 1450 ° C. in 0 minutes, and the pressure was maintained at the predetermined temperature for 5 minutes to perform pressure firing. After firing in this manner, the pressure was completely released and the product was naturally cooled. When the temperature reached 400 ° C., the product was released to the atmosphere to obtain each sintered body.
【００３０】＜実施例５〜７及び参考例２〜４＞混合粉
体原料として、混合粉体３５０ｇ（クロミア粉体を３１
８．５ｇ、ジルコニア粉体を３１．５ｇで全体に対して
ジルコニアを９重量％含有）を用いた以外は実施例１〜
４と同様にして、表１に示した焼結条件でＮｏ．Ｆ〜Ｋ
の６種類の焼結体を得た。<Examples 5 to 7 and Reference Examples 2 to 4> As a mixed powder raw material, 350 g of a mixed powder (31
Example 1 except that 8.5 g, 31.5 g of zirconia powder and 9% by weight of zirconia based on the whole were used.
No. 4 in the same manner as in No. 4 under the sintering conditions shown in Table 1. F to K
Were obtained.
【００３１】（評価）焼成終了後、上記で得られたφ６
０ｍｍ×１０ｍｍの焼結体をＪＩＳ−Ｒ１６０１に準ず
る曲げ強度測定用試料に切断加工し、各焼結体につい
て、下記に述べる方法で、相対密度、曲げ強度、侵食試
験、熱衝撃抵抗性試験を実施してその特性を評価した。
その結果を各焼結体の焼成条件と共に表１に示した。(Evaluation) After the completion of the firing, the φ6 obtained above was obtained.
A sintered body of 0 mm x 10 mm is cut into a sample for bending strength measurement according to JIS-R1601, and the relative density, bending strength, erosion test, and thermal shock resistance test are performed on each sintered body by the method described below. And evaluated its properties.
The results are shown in Table 1 together with the firing conditions of each sintered body.
【００３２】（１）相対密度 アルキメデス法によって相対密度の計測を行なった。即
ち、ＪＩＳ−Ｒ２２０５に準拠して、得られた嵩密度
を、クロミアとジルコニアの理論密度、及びジルコニア
の添加割合を用いて算出したクロミア−ジルコニア焼結
体の理論密度で除して、百分率で表したものを相対密度
とした。(1) Relative density The relative density was measured by the Archimedes method. That is, based on JIS-R2205, the obtained bulk density is divided by the theoretical density of chromia and zirconia, and the theoretical density of the chromia-zirconia sintered body calculated using the addition ratio of zirconia, and expressed as a percentage. What was expressed was defined as relative density.
【００３３】（２）曲げ強度 ＪＩＳ−Ｒ１６０１に準拠し、室温における３点曲げ強
度を測定した。(2) Bending strength A three-point bending strength at room temperature was measured according to JIS-R1601.
【００３４】（３）侵食試験 耐食性の評価は、下記の合成スラグによる侵食試験によ
り行なった。スラグ侵食試験は、試薬から調製した合成
スラグを白金坩堝にいれ、これを電気炉内に設置して試
験温度１５００℃で溶融し、その溶融スラグ中に５０時
間、夫々の焼結体（試料）を浸漬させて実施した。試験
後、焼結体を切断し、ＳＥＭによりスラグとの界面を観
察し、焼結体の減少量を測定して侵食量とし、各焼結体
の耐食性を評価した。(3) Erosion Test The corrosion resistance was evaluated by the following erosion test using synthetic slag. In the slag erosion test, a synthetic slag prepared from a reagent was placed in a platinum crucible, placed in an electric furnace and melted at a test temperature of 1500 ° C., and each sintered body (sample) was melted in the molten slag for 50 hours. Was immersed. After the test, the sintered body was cut, the interface with the slag was observed by SEM, the reduction amount of the sintered body was measured, and the amount of erosion was determined, and the corrosion resistance of each sintered body was evaluated.
【００３５】（４）熱衝撃抵抗性試験 焼結体から切断加工したＪＩＳ−Ｒ１６０１に準拠する
曲げ強度測定用試料をある温度に保持して（これを保持
温度という）縦型管状炉中に吊るし、３０分間保持した
後、急激に水中へ落下させ、乾燥させた後の室温３点曲
げ強さを測定した。先に測定した室温での曲げ強度と比
べて急激に焼結体に強度変化が生じた時の上記保持温度
と水温との差を急冷温度差、ΔＴｃ（℃）と定義した。
このようにして得られるΔＴｃの値が大きいものほど、
熱衝撃抵抗性が良好であると判断できる。(4) Thermal shock resistance test A sample for bending strength measurement according to JIS-R1601 cut from a sintered body is held at a certain temperature (this is called a holding temperature) and suspended in a vertical tubular furnace. After holding for 30 minutes, the mixture was rapidly dropped into water and dried, and the three-point bending strength at room temperature was measured. The difference between the above-mentioned holding temperature and the water temperature when the strength of the sintered body suddenly changed compared with the bending strength at room temperature measured earlier was defined as a quenching temperature difference, ΔTc (° C.).
The larger the value of ΔTc obtained in this way is,
It can be determined that the thermal shock resistance is good.
【００３６】（５）評価結果 表１に示した相対密度の測定結果からわかるように、ク
ロミアに分散させるジルコニアの添加量が多いと、少な
い場合に比べて緻密化が進行しにくいことがわかった。
しかし、ジルコニアの添加量を９重量％と多くした場合
であっても、焼成温度及び加圧力の焼成条件を適宜なも
のとすれば、相対密度の高い緻密な焼結体を得ることが
できることがわかった。例えば、加圧力が４０ＭＰａと
高い場合には、比較的低い１４００℃の焼成温度で９
７．０％以上の相対密度の焼結体が得られるが、加圧力
が３０ＭＰａと低い場合には、同様に９７．０％以上の
相対密度の焼結体を得るためには、それよりも高い１４
５０℃の焼成温度で焼成する必要があることがわかっ
た。(5) Evaluation Results As can be seen from the measurement results of the relative density shown in Table 1, it was found that when the added amount of zirconia dispersed in chromia was large, the densification hardly proceeded as compared with the case where the added amount was small. .
However, even when the addition amount of zirconia is increased to 9% by weight, a dense sintered body having a high relative density can be obtained by appropriately setting the firing conditions such as the firing temperature and the pressing force. all right. For example, when the pressure is as high as 40 MPa, the firing temperature is relatively low at 1400 ° C.
Although a sintered body having a relative density of 7.0% or more can be obtained, when the pressing force is as low as 30 MPa, a sintered body having a relative density of 97.0% or more is similarly required. High 14
It was found that it was necessary to fire at a firing temperature of 50 ° C.
【００３７】焼成条件を加圧力３０ＭＰａ、焼成温度１
４５０℃と一定にし、使用する混合粉体原料中における
ジルコニアの添加量を変えた場合の焼結体について、上
記の曲げ強度試験及び熱衝撃抵抗性試験を行なって、そ
の特性を比較した。この結果、表１中の焼結体Ｎｏ．Ｃ
及びＨに示されているように、ジルコニアの添加量の多
いＮｏ．Ｈの焼結体は、Ｎｏ．Ｃのジルコニアの添加量
の少ない焼結体に比べて室温の曲げ強度が若干低下する
ものの、熱衝撃抵抗性は向上していた。これは、Ｎｏ．
Ｃに比べてジルコニアの添加量の多いＮｏ．Ｈの焼結体
では、組織全体としてジルコニア粒子周辺の空隙や微細
亀裂が増加するので、熱衝撃抵抗性が向上したものと考
えられる。The firing conditions were as follows: a pressure of 30 MPa and a firing temperature of 1
The above-mentioned bending strength test and thermal shock resistance test were performed on the sintered body when the addition amount of zirconia in the mixed powder raw material used was kept constant at 450 ° C., and the characteristics thereof were compared. As a result, the sintered body No. C
As shown in Nos. And H, no. No. H sintered body Although the bending strength at room temperature was slightly reduced as compared with the sintered body containing a small amount of C zirconia, the thermal shock resistance was improved. This is No.
No. C containing a larger amount of zirconia than C. In the sintered body of H, voids and fine cracks around the zirconia particles increase in the entire structure, and it is considered that the thermal shock resistance is improved.
【００３８】[0038]
【表１】 [Table 1]
【００３９】＜実施例８及び９＞混合粉体原料として、
ジルコニアの添加量の異なる下記の２種類の混合粉体を
用い、表２に示した夫々の焼成条件で焼結する以外は実
施例１等と同様にして、実施例８及び９の焼結体Ｌ及び
Ｍを得た。即ち、混合粉体原料として、夫々、実施例１
で使用したと同様のクロミア粉体に、実施例１で使用し
たと同様のジルコニアを用い、これを粉体原料全体に対
して１重量％含有させたものと、粉体原料全体に対して
９重量％含有させたものを用いた。<Examples 8 and 9> As mixed powder raw materials,
The sintered bodies of Examples 8 and 9 were prepared in the same manner as in Example 1 and the like, except that sintering was performed under the respective firing conditions shown in Table 2 using the following two types of mixed powders having different addition amounts of zirconia. L and M were obtained. That is, as a mixed powder raw material,
The same chromia powder as that used in Example 1 was used, and the same zirconia as used in Example 1 was used and contained 1% by weight based on the whole powder raw material, What contained a weight% was used.
【００４０】＜比較例１〜３＞下記の夫々の製造方法
で、比較例１では、ジルコニア粉体を添加せずにクロミ
ア粉体のみを粉体原料として焼結体Ｎｏ．Ｎを得、比較
例２では、ＴｉＯ2及びＳｉＯ2を焼結助剤として含有す
るクロミア粉体を粉体原料とする焼結体Ｎｏ．Ｏを得、
比較例３では、アルミナ粉体のみを粉体原料ととする焼
結体Ｎｏ．Ｐを得た。製造方法としては、Ｎｏ．Ｎの比
較例１の焼結体については、実施例１で使用したと同様
のクロミア粉体を用い、実施例及び参考例の場合と同様
に、放電プラズマ燒結機を用いて、表２に示した焼成条
件で焼成した。又、比較例２では、焼結助剤（ＴｉＯ2
及びＳｉＯ2）を合量で１０重量％使用して、実施例１
で使用したと同様のＣｒ2Ｏ3を９０重量％含む粉体原料
を用いて、先ず、一軸加圧により成形体を作製し、その
後、得られた成形体を大気中で１７５０℃で焼成して、
比較例のクロミア質焼結体Ｎｏ．Ｏを得た。更に、比較
例３では、重量平均粒径２〜３μｍのアルミナ粉体を用
いて、大気中で１６００℃で焼成して、比較例のアルミ
ナ質焼結体Ｎｏ．Ｐを得た。<Comparative Examples 1 to 3> In each of the following production methods, in Comparative Example 1, the sintered body No. 1 was prepared by using only chromia powder as a powder raw material without adding zirconia powder. N was obtained. In Comparative Example 2, a sintered body No. using chromia powder containing TiO 2 and SiO 2 as sintering aids as a powder raw material was used. Get O,
In Comparative Example 3, the sintered body No. using only the alumina powder as the powder material was used. P was obtained. As the manufacturing method, For the sintered body of Comparative Example 1 of N, the same chromia powder as used in Example 1 was used, and the discharge plasma sintering machine was used as shown in Table 2 in the same manner as in Examples and Reference Examples. The firing was performed under the same firing conditions. In Comparative Example 2, the sintering aid (TiO 2
And SiO 2 ) in a total amount of 10% by weight.
First, a compact was prepared by uniaxial pressing using the same powder raw material containing 90% by weight of Cr 2 O 3 as used in the above, and then the obtained compact was fired at 1750 ° C. in the air. hand,
The chromia sintered body No. of the comparative example. O was obtained. Further, in Comparative Example 3, alumina powder having a weight average particle diameter of 2 to 3 μm was fired in the air at 1600 ° C. P was obtained.
【００４１】[0041]
【表２】 [Table 2]
【００４２】（評価）夫々の焼成終了後、得られた焼結
体をＪＩＳ−Ｒ１６０１に準ずる曲げ強度測定用試料に
切断加工し、先に述べたと同様の方法で、相対密度、曲
げ強度、侵食試験、熱衝撃抵抗性試験を実施して、その
特性を夫々評価した。その結果を表３に示した。(Evaluation) After completion of each firing, the obtained sintered body was cut into a sample for measuring bending strength according to JIS-R1601, and the relative density, bending strength, and erosion were obtained in the same manner as described above. A test and a thermal shock resistance test were performed, and the characteristics were evaluated. Table 3 shows the results.
【００４３】表３から明らかなように、先ず、従来法に
従い焼結助剤を用い大気中で焼成した比較例２の焼結体
Ｎｏ．Ｏでは相対密度が９０．２％であったのに対し、
実施例８及び９の焼結体Ｌ及びＭでは相対密度が９７％
以上であり、実施例８及び９の焼結体は、いずれも緻密
なクロミア焼結体であることが確認できた。更に、比較
例２の焼結体Ｎｏ．Ｏに比べて、実施例８及び９の焼結
体Ｌ及びＭは、格段に耐食性に優れていることもわかっ
た。これは、比較例２のＮｏ．Ｏの焼結体は、ジルコニ
アと異なり、クロミアの粒界に液相になり易い不純物
（ＴｉＯ2及びＳｉＯ2）を含むため、耐食性が劣るもの
になったと考えられる。以上のように、ジルコニアの添
加量に関わらず、実施例８及び９の焼結体Ｌ及びＭは、
Ｎｏ．Ｏの従来のクロミア焼結体に比べて、高い緻密性
を有し、且つ、耐食性に優れていることが確認できた。As is clear from Table 3, first, the sintered body No. of Comparative Example 2 fired in the air using a sintering aid according to the conventional method. In O, the relative density was 90.2%,
In the sintered bodies L and M of Examples 8 and 9, the relative density was 97%.
As described above, it was confirmed that each of the sintered bodies of Examples 8 and 9 was a dense chromia sintered body. Further, the sintered body No. Compared with O, the sintered bodies L and M of Examples 8 and 9 were also found to be much more excellent in corrosion resistance. This corresponds to No. 2 of Comparative Example 2. Unlike the zirconia, the sintered body of O contains impurities (TiO 2 and SiO 2 ) which are likely to be in the liquid phase at the grain boundaries of chromia, so that it is considered that the corrosion resistance is inferior. As described above, regardless of the amount of zirconia added, the sintered bodies L and M of Examples 8 and 9
No. Compared to the conventional chromia sintered body of O, it was confirmed that it had high denseness and was excellent in corrosion resistance.
【００４４】又、表３に示されているように、比較例１
のジルコニアを添加しないクロミアのみからなる焼結体
Ｎｏ．Ｎは、高い相対密度を有し、非常に緻密で耐食性
に優れた材料であることがわかった。しかし、熱衝撃抵
抗性試験を行なった結果、このクロミア焼結体Ｎｏ．Ｎ
は、ジルコニアを添加した実施例８及び９の焼結体Ｌ及
びＭと比較すると、熱衝撃抵抗性に劣ることがわかっ
た。更に、実施例８及び９の焼結体Ｌ及びＭは、この比
較例１のクロミア焼結体Ｎｏ．Ｎと比べてジルコニアの
添加したことに起因して若干の耐食性の低下が見られる
ものの、大きく耐食性が損なわれることはなく、耐食性
と熱衝撃抵抗性との両立が図られていることが確認でき
た。As shown in Table 3, Comparative Example 1
Of sintered body No. consisting of only chromia without the addition of zirconia N was found to be a material having a high relative density, being very dense and having excellent corrosion resistance. However, as a result of performing a thermal shock resistance test, this chromia sintered body No. N
Was found to be inferior in thermal shock resistance as compared with the sintered bodies L and M of Examples 8 and 9 to which zirconia was added. Furthermore, the sintered bodies L and M of Examples 8 and 9 are the same as the chromia sintered bodies No. 1 of Comparative Example 1. Although a slight decrease in corrosion resistance was observed due to the addition of zirconia compared with N, it was confirmed that corrosion resistance was not significantly impaired, and that both corrosion resistance and thermal shock resistance were achieved. Was.
【００４５】更に、表３に示されているように、実施例
８及び９の焼結体Ｌ及びＭは、従来より熱衝撃抵抗性に
優れる材料として用いられている高純度アルミナ焼結体
である比較例３の焼結体Ｐと比べても遜色のない熱衝撃
抵抗性を示すことがわかった。特に、ジルコニア粒子が
９重量％添加されている実施例１０の焼結体Ｍでは、上
記の高純度クロミア焼結体よりも優れた熱衝撃抵抗性を
示すことがわかった。Further, as shown in Table 3, the sintered bodies L and M of Examples 8 and 9 are high-purity alumina sintered bodies conventionally used as materials having excellent thermal shock resistance. It was found that the sintered body P exhibited thermal shock resistance comparable to that of the sintered body P of Comparative Example 3. In particular, it was found that the sintered body M of Example 10 to which 9% by weight of zirconia particles were added exhibited better thermal shock resistance than the above-described high-purity chromia sintered body.
【００４６】[0046]
【表３】 [Table 3]
【００４７】[0047]
【発明の効果】以上説明したように、本発明によれば、
クロミアの緻密な組織中に特定の大きさのジルコニア粒
子を特定の割合で均一に分散させることで、焼結体の緻
密性を低下させることがなく、耐食性に優れ、しかも熱
衝撃抵抗性を向上を実現させたクロミア−ジルコニア焼
結体が提供される。又、本発明によれば、上記のような
優れたクロミア−ジルコニア焼結体が容易に経済的に得
られるクロミア−ジルコニア焼結体の製造方法が提供さ
れる。更に、本発明によれば、高温での耐食性及び熱衝
撃抵抗性に優れ、ガラス溶解炉や廃棄物処理溶融炉等に
おいて長期使用可能な高温耐食性材料として好適な、ク
ロミア−ジルコニア焼結体が提供される。As described above, according to the present invention,
By uniformly dispersing zirconia particles of a specific size at a specific ratio in the dense structure of chromia, it does not reduce the denseness of the sintered body, has excellent corrosion resistance, and improves thermal shock resistance Provided is a chromia-zirconia sintered body. Further, according to the present invention, there is provided a method for producing a chromia-zirconia sintered body from which the above-described excellent chromia-zirconia sintered body can be easily and economically obtained. Further, according to the present invention, there is provided a chromia-zirconia sintered body which is excellent in corrosion resistance and thermal shock resistance at high temperatures and is suitable as a high-temperature corrosion-resistant material which can be used for a long time in a glass melting furnace, a waste treatment melting furnace, and the like. Is done.
【図１】本発明のクロミア−ジルコニア焼結体をＳＥＭ
で組織観察した結果を示す概略図である。FIG. 1 shows an SEM of a chromia-zirconia sintered body of the present invention.
It is the schematic which shows the result of structure | tissue observation.
【図２】本発明のクロミア−ジルコニア焼結体を得るた
めの粉体試料の充填容器を示す概略図である。FIG. 2 is a schematic view showing a container for filling a powder sample for obtaining a chromia-zirconia sintered body of the present invention.
フロントページの続き (72)発明者 大河 誠 愛知県半田市亀崎北浦町一丁目46番地 美 濃窯業株式会社技術研究所内 (72)発明者 梶田 吉晴 愛知県半田市亀崎北浦町一丁目46番地 美 濃窯業株式会社技術研究所内 Ｆターム(参考） 4G030 AA17 AA22 BA25 CA04 GA11 GA27 4K051 AA03 AA09 AB03 BE03 Continued on the front page (72) Inventor Makoto Okawa 1-46 Kamezaki-Kitaura-cho, Handa-shi, Aichi Prefecture Inside the Technical Research Institute of Minoh Ceramics Co., Ltd. F-term in the Ceramics Research Laboratory (reference) 4G030 AA17 AA22 BA25 CA04 GA11 GA27 4K051 AA03 AA09 AB03 BE03
Claims (6)
し、且つ、クロミア粒子からなる組織中に重量平均粒子
径１０〜８０μｍのジルコニア粒子が全体に対して０．
１〜１５重量％の割合で均一に分散されていることを特
徴とするクロミア−ジルコニア焼結体。A zirconia particle having a dense structure with a relative density of 97% or more and a weight average particle diameter of 10 to 80 μm in the structure composed of chromia particles is contained in the chromium particles at a ratio of 0.1 to 80%.
A chromia-zirconia sintered body which is uniformly dispersed at a ratio of 1 to 15% by weight.
の範囲にあり、且つ、ジルコニア粒子の周辺のクロミア
焼結組織中に空隙及び／又は微細な亀裂を有する請求項
１に記載のクロミア−ジルコニア焼結体。2. The chromia particles have an average particle size of 1 to 3 μm.
The chromia-zirconia sintered body according to claim 1, wherein the chromia-zirconia sintered body has voids and / or fine cracks in a chromia sintered structure around the zirconia particles.
焼結体を製造するためのクロミア−ジルコニア焼結体の
製造方法であって、クロミア粉体に重量平均粒子径１０
〜８０μｍのジルコニア粉体を粉体原料の全量に対して
０．１〜１５重量％になるように加えて均一に分散させ
て混合粉体とし、該混合粉体を真空中若しくは不活性雰
囲気中で加圧しながらパルス通電加熱して成形及び焼成
することを特徴とするクロミア−ジルコニア焼結体の製
造方法。3. A method for producing a chromia-zirconia sintered body for producing the chromia-zirconia sintered body according to claim 1, wherein the chromia powder has a weight average particle diameter of 10%.
８０80 μm of zirconia powder is added in an amount of 0.1 to 15% by weight with respect to the total amount of the powder raw material and uniformly dispersed to obtain a mixed powder, and the mixed powder is placed in a vacuum or in an inert atmosphere. A method for producing a chromia-zirconia sintered body, characterized in that pulsed electric heating is performed while applying pressure to form and sinter.
の範囲にある請求項３に記載のクロミア−ジルコニア焼
結体の製造方法。4. The chromia powder has an average particle size of 1 to 3 μm.
The method for producing a chromia-zirconia sintered body according to claim 3, wherein
０〜６０ＭＰａの範囲で焼成を行なう請求項３又は４に
記載のクロミア−ジルコニア焼結体の製造方法。5. A firing temperature of 1200 to 1600 ° C. and a load of 1
The method for producing a chromia-zirconia sintered body according to claim 3, wherein the firing is performed in a range of 0 to 60 MPa.
０〜４０ＭＰａの範囲で焼成を行なう請求項３又は４に
記載のクロミア−ジルコニア焼結体の製造方法。6. A firing temperature of 1400 to 1500 ° C. and a load of 2
The method for producing a chromia-zirconia sintered body according to claim 3, wherein the firing is performed in a range of 0 to 40 MPa.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000085009A JP4430782B2 (en) | 2000-03-24 | 2000-03-24 | CHROMIA-ZIRCONIA SINTERED BODY AND PROCESS FOR PRODUCING THE SAME |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000085009A JP4430782B2 (en) | 2000-03-24 | 2000-03-24 | CHROMIA-ZIRCONIA SINTERED BODY AND PROCESS FOR PRODUCING THE SAME |
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|---|---|
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| JP4430782B2 JP4430782B2 (en) | 2010-03-10 |
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|---|---|---|---|
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008532915A (en) * | 2005-03-15 | 2008-08-21 | サン−ゴベン・セントル・ドゥ・レシェルシェ・エ・デチュード・ユーロペアン | Gasification reactor internal lining |
| EP1982965A1 (en) * | 2005-05-30 | 2008-10-22 | Refractory Intellectual Property GmbH & Co. KG | Refractory ceramic product |
| CN115093237A (en) * | 2022-06-09 | 2022-09-23 | 中钢集团洛阳耐火材料研究院有限公司 | Preparation method of compact chromium oxide product with high thermal shock resistance |
-
2000
- 2000-03-24 JP JP2000085009A patent/JP4430782B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008532915A (en) * | 2005-03-15 | 2008-08-21 | サン−ゴベン・セントル・ドゥ・レシェルシェ・エ・デチュード・ユーロペアン | Gasification reactor internal lining |
| EP1982965A1 (en) * | 2005-05-30 | 2008-10-22 | Refractory Intellectual Property GmbH & Co. KG | Refractory ceramic product |
| CN115093237A (en) * | 2022-06-09 | 2022-09-23 | 中钢集团洛阳耐火材料研究院有限公司 | Preparation method of compact chromium oxide product with high thermal shock resistance |
| CN115093237B (en) * | 2022-06-09 | 2023-06-16 | 中钢集团洛阳耐火材料研究院有限公司 | Preparation method of compact chromium oxide product with high thermal shock resistance |
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|---|---|
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