JP3612770B2 - Manufacturing method of ceramic foam - Google Patents
Manufacturing method of ceramic foam Download PDFInfo
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- JP3612770B2 JP3612770B2 JP04543995A JP4543995A JP3612770B2 JP 3612770 B2 JP3612770 B2 JP 3612770B2 JP 04543995 A JP04543995 A JP 04543995A JP 4543995 A JP4543995 A JP 4543995A JP 3612770 B2 JP3612770 B2 JP 3612770B2
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
- C04B38/02—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by adding chemical blowing agents
Description
【０００１】
【産業上の利用分野】
本発明は発泡セラミックスの製造方法に係り、特に、製品寸法のばらつきが少なく、寸法安定性に優れた発泡セラミックスの製造方法に関する。
【０００２】
【従来の技術及び先行技術】
発泡セラミックスは、その軽量性、断熱性等の優れた特性を利用して、各種建築材料等として広く利用されている。
【０００３】
従来、発泡セラミックスは、炭化珪素等のガス発生剤を含む発泡性セラミックス原料を成形、焼成し、この焼成過程でガス発生剤を発泡させて製造されている。
【０００４】
ところで、セラミックスは焼成により収縮して緻密化するが、発泡セラミックスの焼成においては、焼成収縮による緻密化と、ガス発生剤の発泡による膨張の過程とを経ることになるため、この収縮による寸法変化と膨張による寸法変化という、相反する２つの寸法変化を受けることにより、得られる製品の寸法のばらつきが大きいという欠点がある。
【０００５】
上記従来の問題点を解決し、焼成時の寸法変化が小さく、寸法安定性に優れた発泡セラミックスを製造する方法として、本出願人は、先に、「耐火度の異なる複数の発泡性原料粉末をそれぞれ造粒し、造粒された粒子を乾式混合した後成形し、この成形体を焼成することを特徴とする発泡セラミックスの製造方法」を提案した（特願平６−３８３１９号。以下「先願」という。）
上記先願の方法によれば、焼成時に低耐火度相の膨張に高耐火度相の収縮が併行することにより、全体的な寸法変化が低減され、製品の寸法安定性が向上する。
【０００６】
【発明が解決しようとする課題】
ところで、発泡剤を混合して発泡性原料粉末を調製する場合、一般に発泡剤の使用量は他のセラミックス原料に対して非常に少ない量であるため、これを均一に分散混合することは容易ではない。
【０００７】
しかしながら、上記先願の方法においては、少なくとも２種類の発泡性原料粉末の調製を行う必要があるため、少なくとも２回の発泡剤の均一混合処理が必要となり、原料調製に手間を要するという不具合がある。
【０００８】
本発明に上記先願の問題点を解決し、原料粉末の調製における発泡剤の混合処理を軽減することができ、しかも、寸法安定性に優れた発泡性セラミックスを容易に製造することが可能な発泡セラミックスの製造方法を提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明の発泡セラミックスの製造方法は、耐火度の異なる複数の原料粉末をそれぞれ造粒し、造粒された粒子を乾式混合した後成形し、この成形体を焼成する発泡セラミックスの製造方法であって、最も耐火度の高い高耐火度原料粉末は発泡剤を含み、最も耐火度の低い低耐火度原料粉末は発泡剤を含まないものとし、かつ、該高耐火度原料粉末の磁器化温度と低耐火度原料粉末の磁器化温度との温度差を２００〜４００℃とすることを特徴とする。
【００１０】
以下に本発明を詳細に説明する。
【００１１】
本発明の方法においては、まず、耐火度の異なる複数の原料粉末、例えば比較的耐火度の高い高耐火度原料粉末と、比較的耐火度の低い低耐火度原料粉末を調製し、各々造粒する。この場合、高耐火度原料粉末は発泡剤を含む高耐火度発泡性原料粉末とし、一方、低耐火度原料粉末は発泡剤を含まない低耐火度非発泡性原料粉末とし、かつ、高耐火度発泡性原料粉末の磁器化温度（最も密度が大きくなる焼成温度）と低耐火度非発泡性原料粉末の磁器化温度との温度差が２００〜４００℃となるようにする。
【００１２】
本発明において、高耐火度発泡性原料としては、例えば、下記配合のものを用いることができ、また、低耐火度非発泡性原料粉末としては、ガラスフリット、天然ガラス等の低耐火度材料を用いて所定の耐火度が得られるような割合で配合した、下記配合のものを用いることができる。なお、下記配合において、ガス発生剤としては、炭化珪素、窒化珪素等を用いることができる。
【００１３】
高耐火度発泡性原料配合（重量部）
長 石 ：４０〜９０
粘 土 ：１０〜６０
ガス発生剤 ：０．０１〜２
低耐火度発泡性原料粉末配合（重量部）
ガラスフリット：２０〜１００
天然ガラス ：０〜８０
長 石 ：０〜７０
粘 土 ：０〜３０
本発明において、高耐火度発泡性原料と低耐火度非発泡性原料との磁器化温度の温度差が２００℃未満であると、良好な寸法安定性が得られなくなる。また、この温度差が４００℃を超えると均一な発泡セラミックスが得られなくなる。このため、高耐火度発泡性原料と低耐火度非発泡性原料との磁器化温度の温度差は２００〜４００℃好ましくは２１０〜３５０℃とする。
【００１４】
このような高耐火度発泡性原料粉末及び低耐火度非発泡性原料粉末は、各々造粒する（以下、高耐火度発泡性原料粉末より得られた造粒粒子を「高耐火度造粒物」、低耐火度非発泡性原料粉末より得られた造粒粒子を「低耐火度造粒物」と称す。）。
【００１５】
ここで、高耐火度造粒物及び低耐火度造粒物は、小さ過ぎても大き過ぎても本発明による焼成時の寸法変化の緩和効果が十分に得られない。高耐火度造粒物及び低耐火度造粒物の粒径は５ｍｍ以下、特に０．１〜２ｍｍとするのが好ましい。
【００１６】
得られた高耐火度造粒物と低耐火度造粒物は、乾式混合してプレス成形し、次いで焼成する。ここで、高耐火度造粒物と低耐火度造粒物との混合割合は、少なくとも一方の造粒粒子が１０重量％以上となるように、即ち、高耐火度造粒物：低耐火度造粒物＝１０〜９０：９０〜１０（重量％）、好ましくは３０〜７０：７０〜３０（重量％）となるようにするのが好ましい。
【００１７】
焼成温度は、用いた高耐火度発泡性原料粉末と低耐火度非発泡性原料粉末の磁器化温度、その混合割合、目的とする発泡セラミックスの気孔率等により異なるが、通常の場合、８００〜１３００℃の範囲で適宜決定される。
【００１８】
なお、上記説明では、高耐火度発泡性原料と低耐火度非発泡性原料との２種類の原料粉末を用いる場合について示したが、本発明においては、耐火度の異なる３種類以上の原料粉末を用いても良いことは言うまでもない。この場合、最も耐火度の高い原料と最も耐火度の低い原料との中間の耐火度を有する原料については、発泡剤を含有するものであっても、発泡剤を含有しないものであっても、いずれでも良い。また、この場合においても、中間の耐火度を有する各発泡性又は非発泡性原料粉末を少なくとも１０重量％混合することが望ましい。
【００１９】
【作用】
耐火度の異なる複数の原料を造粒したものを乾式混合して、成形することにより、得られた成形体は、耐火度の異なる複数の相が分散して混在した状態となる。
【００２０】
高耐火度発泡性原料より得られた高耐火度造粒物で形成される相（以下「高耐火度相」と称す。）と低耐火度非発泡性原料より得られた低耐火度造粒物で形成される相（以下「低耐火度相」と称す。）とが分散して混在した状態の成形体を焼成すると、温度上昇に伴い、まず、成形体素地中の低耐火度相が収縮し始める。更に、焼成温度が上昇すると、低耐火度相が溶融し始めるが、このとき、高耐火度相中のガス発生剤から発生したガスが低耐火度相の溶融相に捕捉されて低耐火度相の発泡が起こる。この時、高耐火度相は収縮過程にあり、その後焼成温度の上昇と共に発泡により膨張する。
【００２１】
即ち、焼結体の焼結温度と嵩比重との関係を模式的に表わす図１において点線で示されるように、まず低耐火度相は、焼成温度上昇に伴って収縮し始める。低耐火度相は、その磁器化温度Ｔ１ に到るまで嵩比重が大きくなり、その後、更に焼成温度が上昇すると次第に軟化し、高耐火度相の粒子間隙を軟化物質で満たすようになる。そして、高耐火度相の発泡剤から発生するガスを捕捉し、発泡する。
【００２２】
高耐火度相だけを焼成した場合には、図１に一点鎖線で示す如く、高耐火度相は、その磁器化温度Ｔ２ に到るまで嵩比重が大きくなり、その後発泡により膨張し、嵩比重が小さくなる。
【００２３】
ところが、低耐火度相と高耐火度相とを混在させると、低耐火度相が高耐火度相からの発生ガスを捕捉して発泡するため、高耐火度相の磁器化温度Ｔ２ よりも低い温度で混合素地の嵩比重低下が開始するようになる。この結果、この混合素地の焼成温度変化による嵩比重の変化は、図１に実線で示す如く、なだらかな曲線となる。
【００２４】
このように、焼成温度が変化しても嵩比重の変動が小さいため、目標値通りの嵩比重の発泡セラミックスを容易に製造できるようになる。また、焼成温度が変化しても、素地の寸法変化が小さいため、発泡セラミックス製品の寸法安定性が高められる。
【００２５】
本発明において、高耐火度相の磁器化温度Ｔ２ と低耐火度相の磁器化温度Ｔ１ との差（Ｔ２ −Ｔ１ ）が２００℃よりも小さいときには、低耐火度相の軟化開始が遅すぎ、混合素地全体の嵩比重低下開始温度が高耐火度相の磁器化温度Ｔ２ に近接し、焼成温度上昇に伴う嵩比重低下が急激なものとなる。一方、（Ｔ２ −Ｔ１ ）が４００℃よりも大きいと、高耐火度相が膨張しないうちに低耐火度相が溶融してガラス融液状となり、高耐火度相から発生したガスが素地表面を突き破って素地外に放出される。そして、焼成後の素地表面は、ガスが抜け出た跡がクレーター状に残留した面性状の悪いものとなる。
【００２６】
【実施例】
以下に実施例及び比較例を挙げて本発明をより具体的に説明する。
【００２７】
実施例１
下記配合の高耐火度発泡性原料粉末Ｉと低耐火度非発泡性原料粉末Ｉとを用い、各々、粒径０．５〜１．５ｍｍに造粒した。なお、下記高耐火度発泡性原料粉末Ｉの磁器化温度は１２００℃、低耐火度非発泡性原料粉末Ｉの磁器化温度は９００℃で、その温度差は３００℃である。
【００２８】
高耐火度発泡性原料粉末配合Ｉ（重量％）
長 石 ：７０
粘 土 ：３０
ＳｉＣ ：０．１５
低耐火度非発泡性原料粉末配合Ｉ（重量％）
ガラスフリット：１００
造粒により得られた高耐火度造粒物Ｉと低耐火度造粒物Ｉとを７０：３０（重量比）の割合でロッキングミキサーにて乾式混合し、混合物をプレス成形した。
【００２９】
この成形体を１１００℃で焼成し、得られた焼結体の嵩比重と面性状を調べ、結果を表１に示した。
【００３０】
なお、表１には、この成形体を十分に焼結させた場合の嵩比重（以下「最高嵩比重」と称す。）、及び、この最高嵩比重と得られた焼結体の嵩比重との差（以下「嵩比重差」と称す。）も併記した。
【００３１】
実施例２
実施例１で用いた高耐火度発泡性原料粉末Ｉと、下記配合の低耐火度非発泡性原料粉末ＩＩとを用い、各々、粒径０．５〜１．５ｍｍに造粒したものを、高耐火度造粒物Ｉ：低耐火度造粒物ＩＩ＝５０：５０（重量比）で乾式混合し、プレス成形した。なお、下記低耐火度非発泡性原料粉末ＩＩの磁器化温度は９８０℃で、高耐火度発泡性原料Ｉの磁器化温度との温度差は２２０℃である。
【００３２】
低耐火度非発泡性原料粉末配合 ＩＩ （重量％）
ガラスフリット：４０
長 石 ：６０
この成形体を１１２０℃で焼成して得られた焼結体の嵩比重及び面性状を調べると共に、最高嵩比重及び嵩比重差を求め、結果を表１に示した。
【００３３】
比較例１
実施例１で用いた高耐火度発泡性原料粉末Ｉと、下記配合の低耐火度非発泡性原料粉末ＩＩＩ とを用い、各々、粒径０．５〜１．５ｍｍに造粒したものを、高耐火度造粒物Ｉ：低耐火度造粒物ＩＩＩ ＝７０：３０（重量比）で乾式混合し、プレス成形した。なお、下記低耐火度非発泡性原料粉末ＩＩＩ の磁器化温度は１１５０℃で、高耐火度発泡性原料Ｉの磁器化温度との温度差は５０℃である。
【００３４】
低耐火度非発泡性原料粉末配合 ＩＩＩ（ 重量％）
長 石 ：１００
この成形体を１２００℃で焼成して得られた焼結体の嵩比重及び面性状を調べると共に、最高嵩比重及び嵩比重差を求め、結果を表１に示した。
【００３５】
比較例２
高耐火度発泡性原料Ｉのみを用い、低耐火度非発泡性原料を用いずに実施例１と同様に造粒、成形し、得られた成形体を１２００℃で焼成した。
【００３６】
得られた焼結体の嵩比重及び面性状を調べると共に、最高嵩比重及び嵩比重差を求め、結果を表１に示した。
【００３７】
比較例３
実施例１で用いた高耐火度発泡性原料粉末Ｉと、下記配合の低耐火度非発泡性原料粉末ＩＶとを用い、各々、粒径０．５〜１．５ｍｍに造粒したものを、高耐火度造粒物Ｉ：低耐火度造粒物ＩＶ＝７０：３０（重量比）で乾式混合し、プレス成形した。なお、下記低耐火度非発泡性原料粉末ＩＶの磁器化温度は７８０℃で、高耐火度発泡性原料Ｉの磁器化温度との温度差は４２０℃である。
【００３８】
低耐火度非発泡性原料粉末配合 ＩＶ （重量％）
ガラスフリット（実施例１のものとは異なる。）：１００
この成形体を１０５０℃で焼成して得られた焼結体の嵩比重及び面性状を調べると共に、最高嵩比重及び嵩比重差を求め、結果を表１に示した。
【００３９】
【表１】
表１より、磁器化温度差が２００〜４００℃の高耐火度発泡性原料粉末と低耐火度非発泡性原料粉末とを用いることにより、所望の比重の発泡セラミックスを寸法精度及び形状精度良く製造できることが明らかである。
【００４１】
【発明の効果】
以上詳述した通り、本発明の発泡セラミックスの製造方法によれば、焼成時の収縮、発泡膨張による総寸法変化が低減され、寸法のばらつきが小さく、製品の寸法安定性が大幅に改善されると共に、所望の嵩比重の製品を容易かつ確実に得ることが可能とされる。
【図面の簡単な説明】
【図１】本発明における焼成温度と嵩比重との関係を説明するグラフである。[0001]
[Industrial application fields]
The present invention relates to a method for producing foamed ceramics, and more particularly, to a method for producing foamed ceramics having little dimensional variation and excellent dimensional stability.
[0002]
[Prior art and prior art]
Foamed ceramics are widely used as various building materials and the like by utilizing their excellent properties such as lightness and heat insulation.
[0003]
Conventionally, foamed ceramics are manufactured by molding and firing a foamable ceramic material containing a gas generating agent such as silicon carbide, and foaming the gas generating agent in this firing process.
[0004]
By the way, ceramics shrink and densify by firing, but firing ceramics undergoes densification by firing shrinkage and expansion process by foaming of the gas generating agent. Due to the two contradictory dimensional changes, i.e., dimensional changes due to expansion, there is a disadvantage that the dimensional variation of the resulting product is large.
[0005]
As a method for solving the above-mentioned conventional problems and producing a foamed ceramic having a small dimensional change at the time of firing and excellent in dimensional stability, the present applicant has previously described “a plurality of foamable raw material powders having different fire resistances”. , Respectively, and after forming the granulated particles, the molded particles are dry-mixed and then molded, and the molded body is fired. Japanese Patent Application No. Hei 6-38319 is proposed. It is called “first application”.)
According to the method of the prior application, the expansion of the low refractory phase simultaneously with the expansion of the high refractory phase during firing reduces the overall dimensional change and improves the dimensional stability of the product.
[0006]
[Problems to be solved by the invention]
By the way, when a foaming raw material powder is prepared by mixing a foaming agent, the amount of foaming agent used is generally very small compared to other ceramic raw materials, so it is not easy to disperse and mix this evenly. Absent.
[0007]
However, in the method of the prior application, since it is necessary to prepare at least two kinds of foamable raw material powders, it is necessary to perform a uniform mixing treatment of the foaming agent at least twice, which requires troublesome preparation of the raw materials. is there.
[0008]
The present invention solves the above-mentioned problems of the prior application, can reduce the mixing treatment of the foaming agent in the preparation of the raw material powder, and can easily produce a foamable ceramic having excellent dimensional stability. It aims at providing the manufacturing method of a ceramic foam.
[0009]
[Means for Solving the Problems]
The method for producing foamed ceramics of the present invention is a method for producing foamed ceramics in which a plurality of raw material powders having different fire resistances are granulated, the granulated particles are dry-mixed and then molded, and the compact is fired. The high refractory raw material powder having the highest fire resistance contains a foaming agent, and the low refractory raw material powder having the lowest fire resistance does not contain the foaming agent. The temperature difference with the porcelainization temperature of the low refractory raw material powder is 200 to 400 ° C.
[0010]
The present invention is described in detail below.
[0011]
In the method of the present invention, first, a plurality of raw material powders having different fire resistance, for example, a high fire resistance raw material powder having a relatively high fire resistance and a low fire resistance raw material powder having a relatively low fire resistance, are prepared, and each granulated. To do. In this case, the high fire resistance raw material powder is a high fire resistance foaming raw material powder containing a foaming agent, while the low fire resistance raw material powder is a low fire resistance non-foaming raw material powder containing no foaming agent, and has a high fire resistance. The temperature difference between the porcelainization temperature of the foamable raw material powder (the firing temperature at which the density becomes the highest) and the porcelainization temperature of the low-fire resistance non-foamable raw material powder is set to 200 to 400 ° C.
[0012]
In the present invention, as the high fire resistance foaming raw material, for example, the following blending can be used, and as the low fire resistance non-foaming raw material powder, a low fire resistance material such as glass frit and natural glass is used. It is possible to use the following compounding compounded in such a ratio that a predetermined fire resistance is obtained. In the following composition, silicon carbide, silicon nitride, or the like can be used as the gas generating agent.
[0013]
High fire resistance foaming raw material combination (parts by weight)
Feldspar: 40-90
Clay: 10-60
Gas generating agent: 0.01-2
Low fire resistance foaming raw material powder formulation (parts by weight)
Glass frit: 20-100
Natural glass: 0-80
Feldspar: 0-70
Clay: 0-30
In the present invention, when the temperature difference in porcelain temperature between the high fire resistance foaming raw material and the low fire resistance non-foaming raw material is less than 200 ° C., good dimensional stability cannot be obtained. On the other hand, if this temperature difference exceeds 400 ° C., uniform foamed ceramics cannot be obtained. For this reason, the temperature difference of the porcelainization temperature of a high fire resistance foaming raw material and a low fire resistance non-foaming raw material shall be 200-400 degreeC, Preferably it is 210-350 degreeC.
[0014]
Such a high fire resistance foaming raw material powder and a low fire resistance non-foaming raw material powder are each granulated (hereinafter, the granulated particles obtained from the high fire resistance foaming raw material powder are referred to as “high fire resistance granulated product”. “The granulated particles obtained from the non-foaming raw material powder with low fire resistance are called“ low fire resistance granulated products ”.).
[0015]
Here, if the high fire resistance granulated product and the low fire resistance granulated product are too small or too large, the effect of mitigating the dimensional change during firing according to the present invention cannot be sufficiently obtained. The particle size of the high fire resistance granulated product and the low fire resistance granulated product is preferably 5 mm or less, particularly preferably 0.1 to 2 mm.
[0016]
The obtained high fire resistance granulated product and low fire resistance granulated product are dry-mixed, press-molded, and then fired. Here, the mixing ratio of the high refractory granulated product and the low refractory granulated product is such that at least one granulated particle is 10% by weight or more, that is, high refractory granulated product: low refractory degree. Granulated product = 10 to 90:90 to 10 (% by weight), preferably 30 to 70:70 to 30 (% by weight).
[0017]
The firing temperature varies depending on the porcelainization temperature of the high fire resistance foaming raw material powder and the low fire resistance non-foaming raw material powder used, the mixing ratio thereof, the porosity of the target foamed ceramics, etc. It is determined appropriately in the range of 1300 ° C.
[0018]
In the above description, the case of using two types of raw material powders of a high fire resistance foaming raw material and a low fire resistance non-foaming raw material has been described. However, in the present invention, three or more types of raw material powders having different fire resistances are used. It goes without saying that can be used. In this case, for a raw material having a fire resistance intermediate between the raw material with the highest fire resistance and the raw material with the lowest fire resistance, even if it contains a foaming agent, it does not contain a foaming agent, Either is fine. Also in this case, it is desirable to mix at least 10% by weight of each foamable or non-foamable raw material powder having an intermediate fire resistance.
[0019]
[Action]
A mixture obtained by granulating a plurality of raw materials having different fire resistances is dry-mixed and molded, whereby the obtained molded body is in a state where a plurality of phases having different fire resistances are dispersed and mixed.
[0020]
A phase formed from a high fire resistance granulated material obtained from a high fire resistance foaming raw material (hereinafter referred to as “high fire resistance phase”) and a low fire resistance granulation obtained from a low fire resistance non-foaming raw material When a molded body in which a phase formed by a product (hereinafter referred to as a “low fire resistance phase”) is dispersed and mixed is fired, first, as the temperature rises, the low fire resistance phase in the green body is Start to contract. Furthermore, when the firing temperature rises, the low refractory phase starts to melt, but at this time, the gas generated from the gas generating agent in the high refractory phase is trapped in the molten phase of the low refractory phase. Foaming occurs. At this time, the high refractory phase is in the contraction process, and then expands due to foaming as the firing temperature increases.
[0021]
That is, as shown by a dotted line in FIG. 1 schematically showing the relationship between the sintering temperature and the bulk specific gravity of the sintered body, first, the low refractory phase starts to shrink as the firing temperature rises. Low refractoriness phase bulk density is increased up to the its porcelain temperature T 1, then softened progressively further firing temperature increases, comprising a particle clearance high refractoriness phase to fill in the softened material. And the gas generated from the foaming agent of the high fire resistance phase is captured and foamed.
[0022]
When only the high refractory phase is fired, as shown by the one-dot chain line in FIG. 1, the high refractory phase increases in bulk specific gravity until reaching the porcelainization temperature T 2 , and then expands by foaming. Specific gravity is reduced.
[0023]
However, when the low refractory phase and the high refractory phase are mixed, the low refractory phase captures and foams the gas generated from the high refractory phase, so that it is more than the porcelainization temperature T 2 of the high refractory phase. The bulk density of the mixed substrate starts to decrease at a low temperature. As a result, the change in the bulk specific gravity due to the change in the firing temperature of the mixed base becomes a gentle curve as shown by the solid line in FIG.
[0024]
Thus, since the fluctuation of the bulk specific gravity is small even when the firing temperature is changed, it becomes possible to easily manufacture the foamed ceramic having the bulk specific gravity as the target value. Further, even if the firing temperature changes, the dimensional stability of the foamed ceramic product is improved because the dimensional change of the substrate is small.
[0025]
In the present invention, when the difference (T 2 −T 1 ) between the porcelainization temperature T 2 of the high refractory phase and the porcelain temperature T 1 of the low refractory phase is smaller than 200 ° C., the softening of the low refractory phase starts. is too slow, the bulk density decreases starting temperature of the whole mixture matrix is close to the porcelain temperature T 2 of the high refractoriness phase, bulk density decreases due to sintering temperature rise becomes sharp. On the other hand, if (T 2 −T 1 ) is higher than 400 ° C., the low refractory phase melts to become a glass melt before the high refractory phase expands, and the gas generated from the high refractory phase becomes the surface of the substrate. Is released outside the substrate. And the base surface after baking becomes a thing with a bad surface property in which the trace which gas escaped remained in the shape of a crater.
[0026]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
[0027]
Example 1
Using the high fire resistance foaming raw material powder I and the low fire resistance non-foaming raw material powder I of the following composition, each was granulated to a particle size of 0.5 to 1.5 mm. In addition, the porcelainization temperature of the following high fire resistance foaming raw material powder I is 1200 degreeC, the porcelainization temperature of the low fire resistance nonfoaming raw material powder I is 900 degreeC, and the temperature difference is 300 degreeC.
[0028]
High fire resistance foaming raw material powder blend I (wt%)
Feldspar: 70
Clay ： 30
SiC: 0.15
Low fire resistance non-foaming raw material powder formulation I (wt%)
Glass frit: 100
The high fire resistance granulated product I and the low fire resistance granulated product I obtained by granulation were dry-mixed at a ratio of 70:30 (weight ratio) with a rocking mixer, and the mixture was press-molded.
[0029]
This compact was fired at 1100 ° C., the bulk specific gravity and surface properties of the obtained sintered body were examined, and the results are shown in Table 1.
[0030]
In Table 1, the bulk specific gravity (hereinafter referred to as “maximum bulk specific gravity”) when the molded body is sufficiently sintered, and the maximum bulk specific gravity and the bulk specific gravity of the obtained sintered body are shown. (Hereinafter referred to as “bulk specific gravity difference”).
[0031]
Example 2
Using the high fire resistance foaming raw material powder I used in Example 1 and the low fire resistance non-foaming raw material powder II of the following composition, each granulated to a particle size of 0.5 to 1.5 mm, A high fire resistance granulated product I: a low fire resistance granulated product II = 50: 50 (weight ratio) was dry-mixed and press-molded. The porcelainization temperature of the following low fire resistance non-foaming raw material powder II is 980 ° C., and the temperature difference from the porcelainization temperature of the high fire resistance foaming raw material I is 220 ° C.
[0032]
Low fire resistance non-foaming raw material powder blend II (wt%)
Glass frit: 40
Feldspar ： 60
While examining the bulk specific gravity and surface property of the sintered body obtained by firing this molded body at 1120 ° C., the maximum bulk specific gravity and the bulk specific gravity difference were determined, and the results are shown in Table 1.
[0033]
Comparative Example 1
Using the high fire resistance foaming raw material powder I used in Example 1 and the low fire resistance non-foaming raw material powder III having the following composition, each granulated to a particle size of 0.5 to 1.5 mm, A high fire resistance granulated product I: a low fire resistance granulated product III = 70: 30 (weight ratio) was dry-mixed and press-molded. In addition, the porcelainization temperature of the following low fire resistance non-foaming raw material powder III is 1150 ° C., and the temperature difference from the porcelainization temperature of the high fire resistance foaming raw material I is 50 ° C.
[0034]
Low fire resistance non-foaming raw material powder blend III ( wt%)
Feldspar: 100
While examining the bulk specific gravity and surface properties of the sintered body obtained by firing this molded body at 1200 ° C., the maximum bulk specific gravity and the bulk specific gravity difference were determined, and the results are shown in Table 1.
[0035]
Comparative Example 2
Granulation and molding were performed in the same manner as in Example 1 using only the high fire resistance foaming raw material I and not using the low fire resistance non-foaming raw material, and the resulting molded body was fired at 1200 ° C.
[0036]
While examining the bulk specific gravity and surface property of the obtained sintered body, the maximum bulk specific gravity and the bulk specific gravity difference were determined, and the results are shown in Table 1.
[0037]
Comparative Example 3
Using the high fire resistance foaming raw material powder I used in Example 1 and the low fire resistance nonfoaming raw material powder IV of the following composition, each granulated to a particle size of 0.5 to 1.5 mm, A high fire resistance granulated product I: a low fire resistance granulated product IV = 70: 30 (weight ratio) was dry-mixed and press-molded. In addition, the porcelainization temperature of the following low fire resistance non-foaming raw material powder IV is 780 ° C., and the temperature difference from the porcelainization temperature of the high fire resistance foaming raw material I is 420 ° C.
[0038]
Low fire resistance non-foaming raw material powder formulation IV (wt%)
Glass frit (different from that of Example 1): 100
While examining the bulk specific gravity and surface properties of the sintered body obtained by firing this molded body at 1050 ° C., the maximum bulk specific gravity and the bulk specific gravity difference were determined, and the results are shown in Table 1.
[0039]
[Table 1]
From Table 1, by using a high fire resistance foaming raw material powder having a porcelain temperature difference of 200 to 400 ° C. and a low fire resistance non-foaming raw material powder, it is possible to produce a foam ceramic having a desired specific gravity with high dimensional accuracy and shape accuracy. Obviously you can.
[0041]
【The invention's effect】
As described above in detail, according to the method for producing a foamed ceramic of the present invention, the total dimensional change due to shrinkage and expansion during firing is reduced, the dimensional variation is small, and the dimensional stability of the product is greatly improved. In addition, it is possible to easily and reliably obtain a product having a desired bulk specific gravity.
[Brief description of the drawings]
FIG. 1 is a graph illustrating the relationship between a firing temperature and bulk specific gravity in the present invention.
Claims (1)
最も耐火度の高い高耐火度原料粉末は発泡剤を含み、最も耐火度の低い低耐火度原料粉末は発泡剤を含まないものとし、かつ、該高耐火度原料粉末の磁器化温度と低耐火度原料粉末の磁器化温度との温度差を２００〜４００℃とすることを特徴とする発泡セラミックスの製造方法。A method for producing a foamed ceramic in which a plurality of raw material powders having different fire resistances are granulated, the granulated particles are dry mixed and then molded, and the molded body is fired.
The high fire resistance raw material powder having the highest fire resistance contains a foaming agent, and the low fire resistance raw material powder having the lowest fire resistance does not contain the foaming agent. A method for producing foamed ceramics, characterized in that the temperature difference from the porcelainization temperature of the raw material powder is 200 to 400 ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04543995A JP3612770B2 (en) | 1995-03-06 | 1995-03-06 | Manufacturing method of ceramic foam |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04543995A JP3612770B2 (en) | 1995-03-06 | 1995-03-06 | Manufacturing method of ceramic foam |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08239280A JPH08239280A (en) | 1996-09-17 |
| JP3612770B2 true JP3612770B2 (en) | 2005-01-19 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04543995A Expired - Fee Related JP3612770B2 (en) | 1995-03-06 | 1995-03-06 | Manufacturing method of ceramic foam |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3612770B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IL125855A (en) | 1998-04-06 | 2007-06-03 | Technion R & D Foundation Ltd | Method of producing ceramic foams |
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1995
- 1995-03-06 JP JP04543995A patent/JP3612770B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08239280A (en) | 1996-09-17 |
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