JP2658776B2 - Sinterable alumina and method for producing the same - Google Patents
Sinterable alumina and method for producing the sameInfo
- Publication number
- JP2658776B2 JP2658776B2 JP4312657A JP31265792A JP2658776B2 JP 2658776 B2 JP2658776 B2 JP 2658776B2 JP 4312657 A JP4312657 A JP 4312657A JP 31265792 A JP31265792 A JP 31265792A JP 2658776 B2 JP2658776 B2 JP 2658776B2
- Authority
- JP
- Japan
- Prior art keywords
- alumina
- spinel
- aqueous solution
- water
- acid
- 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
Description
【０００１】[0001]
【産業上の利用分野】本発明は、主として表面に少量の
スピネル層を形成した易焼結性アルミナ並びにそれを得
るためのバイヤ−法水酸化アルミニウム及び／又は中間
アルミナを原料とした易焼結性アルミナの製造方法に関
するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easily sinterable alumina having a small amount of spinel layer formed on its surface and an easy sintering method using aluminum hydroxide and / or intermediate alumina as a raw material for obtaining the alumina. The present invention relates to a method for producing porous alumina.
【０００２】[0002]
【従来の技術】アルミナ粉末は、セラミックス製品、研
磨材、耐火物或いはＩＣ基板等各種の焼結体原料として
汎用されているが、それらの用途の何れに於いても要求
品質が年々厳しくなっている。それへの主たる対応法と
して、焼結原料配合で工夫する方法或いは原料アルミナ
自体を工夫する方法がある。例えば、アルミナ焼結体を
得る際に、アルミナ焼結原料中にマグネシウム化合物を
配合することが特開昭５８−２２３６６３号公報或いは
特開昭５９−１６２１７０号公報等に提案されており、
スピネルの存在でアルミナの異常粒成長を抑制して従来
より高品位の焼結体を得ることが提案されている。しか
し、この方法でも、従来より低い焼結温度としたり微細
で均一な組織の焼結体を得ることが不十分であった。ま
た、アルミナ自体をより低温で焼結し易いアルミナとす
る方法としては、アルミナ自体を微粒状や特定の粒度配
合のものとすることが提案されているが、微粒化コスト
や微粒粉体の取扱性などの点から、限界に近づきつつあ
る。例えば、微粉砕アルミナを適用する方法もあるが、
このようなアルミナは、数十μｍ〜百数十μｍレベルの
状態から１μｍ以下のレベルにするために、解砕更に進
んで粉砕操作を経て製造されている。しかし、このよう
なアルミナは、解砕及び粉砕操作に長時間必要として製
造コストがかさむと共に不純物が混入したり、得られた
アルミナ粒子の形状及び大きさも不揃いなものであるこ
とが多く、一定以上の高密度のものが得られ難いなどの
問題がある。一方、アルミナ表面にマグネシウムイオン
やカルシウムイオンを担持させるさせる方法も考えられ
るが、アルミナをスラリ−鋳込み法で成形する際に、ス
ラリ−粘度が経時的に上昇する現象が見られ、このため
高濃度スラリ−を調製して高密度焼結体を得ることが困
難である事実がある。更に、高品位の焼結体を得るため
に、用途に応じて、低ソ−ダ質（０．０１重量％以下）
や低放射性元素質（０．０５ｐｐｍ以下）のアルミナを
適用することが試みられているが、そのための特別な工
程を経て製造されているため、原料コストが高くなると
いう問題がある。2. Description of the Related Art Alumina powder is widely used as a raw material for various sintered products such as ceramic products, abrasives, refractories, and IC substrates. I have. As a main solution to this, there is a method of devising by mixing the sintering raw material or a method of devising the raw material alumina itself. For example, when obtaining an alumina sintered body, it has been proposed in JP-A-58-223663 or JP-A-59-162170 to incorporate a magnesium compound into an alumina sintering raw material.
It has been proposed that the presence of spinel suppresses abnormal grain growth of alumina to obtain a higher quality sintered body than before. However, even with this method, it has been insufficient to set the sintering temperature lower than before or to obtain a sintered body having a fine and uniform structure. Further, as a method of converting alumina itself into an alumina that can be easily sintered at a lower temperature, it has been proposed to make the alumina itself into fine particles or a compound having a specific particle size. In terms of gender, it is approaching its limits. For example, there is a method of applying finely ground alumina,
Such alumina is manufactured through a crushing operation and a crushing operation in order to reduce the state from several tens of μm to one hundred and several tens of μm to a level of 1 μm or less. However, such alumina is required for a long time for the crushing and pulverizing operations, so that the production cost is increased and impurities are mixed in.Also, the shape and size of the obtained alumina particles are often not uniform, and more than a certain amount. Is difficult to obtain. On the other hand, a method of supporting magnesium ions or calcium ions on the alumina surface is also conceivable. However, when the alumina is formed by the slurry casting method, a phenomenon in which the slurry viscosity increases with time is observed, and therefore, the high concentration There is a fact that it is difficult to prepare a slurry to obtain a high-density sintered body. Furthermore, in order to obtain a high-quality sintered body, low soda quality (0.01% by weight or less) depending on the application.
And the use of low-radioactive elemental (0.05 ppm or less) alumina have been attempted, but since they are manufactured through a special process for that purpose, there is a problem that the raw material cost increases.
【０００３】[0003]
【発明が解決しようとする課題】本発明者らは、従来に
於ける上記課題に対して種々検討した結果、アルミナ粒
子表面にスピネル層を形成することによって、易焼結性
アルミナを得ることが出来ることを見出したものであ
る。また、そのように表面処理したアルミナを引き続い
て希薄な酸又は塩基で洗浄処理することによって、表面
のスピネル層を溶解させることなく、スラリ−流動性の
改善や脱放射性元素化が可能であることを見出したもの
である。As a result of various studies on the above-mentioned problems in the prior art, the present inventors have found that by forming a spinel layer on the surface of alumina particles, it is possible to obtain easily sinterable alumina. I found what I could do. Also, by washing the surface-treated alumina with a dilute acid or base subsequently, it is possible to improve the slurry fluidity and de-radiation elementization without dissolving the spinel layer on the surface. Is found.
【０００４】[0004]
【課題を解決するための手段】即ち、本願の第一発明
は、主として表面にスピネル層を０．０７〜１．０５重
量％形成したアルミナであることを特徴とする易焼結性
アルミナである。また、第二発明は、水酸化アルミニウ
ム及び／又は中間アルミナを塩酸及び／又は塩化アルミ
ニウムと水溶性で且つ酸溶解性のマグネシウム塩とから
成るスピネル化剤水溶液で湿潤してＭｇＯ換算０．０２
〜０．３重量％のマグネシウム塩を担持させた後、シャ
モット質容器に充填して１０００〜１４００℃で焼成す
ることを特徴とする易焼結性アルミナの製造方法であ
る。更に、本願の第三発明は、焼成後、引き続いて希酸
水溶液及び／又は希塩基水溶液で洗浄処理することを特
徴とする請求項２に記載の易焼結性アルミナの製造方法
である。That is, the first invention of the present application is an easily sinterable alumina characterized by being an alumina having a spinel layer formed on the surface in an amount of 0.07 to 1.05% by weight. . Further, the second invention provides an aluminum hydroxide and / or intermediate alumina which is wetted with an aqueous solution of a spinel agent comprising hydrochloric acid and / or aluminum chloride and a water-soluble and acid-soluble magnesium salt to obtain a 0.02% MgO equivalent.
A method for producing easily sinterable alumina, characterized in that a magnesium salt of about 0.3% by weight is supported, and then filled in a chamotte container and fired at 1000 to 1400 ° C. Further, the third invention of the present application is the method for producing easily sinterable alumina according to claim 2, wherein after the calcination, a washing treatment is carried out with a dilute acid aqueous solution and / or a dilute base aqueous solution.
【０００５】本発明において使用する原料水酸化アルミ
ニウムは、工業的に大量生産され安価に入手可能なバイ
ヤ−法によって製造されるギブサイト型水酸化アルミニ
ウムを用いることが経済的に有利である。また、原料中
間アルミナはそれを５００〜１０００℃で焼成して得た
α化率が１０％以下であってＢＥＴ比表面積が８〜１０
０ｍ2 ／ｇのアルミナを用いるのが実用的であり、所望
によって原料としてこれらの両者の混合体を使用するこ
とも出来る。それらは、平均粒径５〜１５０μｍのもの
が汎用的であり、アルミナ換算純度が９９．６重量％以
上で全ソ−ダ含有量０．０５〜０．４重量％、ウランや
トリウム等の放射性元素含有量が２ｐｐｍ以下のものが
好ましい。このような水酸化アルミニウム及び／又は中
間アルミナ（以下、両者を含み「原料アルミナ」ともい
う）をスピネル化剤水溶液で湿潤処理する。スピネル化
剤水溶液は、塩酸及び／又は塩化アルミニウムと水溶性
で且つ酸溶解性のマグネシウム塩とから成る。この場
合、塩酸及び／又は塩化アルミニウムが原料アルミナ表
面を活性状態にすると共に原料アルミナの焼成時の吹き
溢れ防止剤として機能し、一方、マグネシウム塩がアル
ミナ表面のスピネル化剤として機能するものである。ス
ピネル化剤水溶液は、全体として、原料アルミナ１ｋｇ
に対して、塩酸及び／又は塩化アルミニウムを塩素イオ
ン（Ｃｌ- ）として２〜２０ｇの範囲になるように、ま
た水溶性で且つ酸溶解性のマグネシウム塩が酸化マグネ
シウムＭｇＯ換算で０．２〜３．０ｇの範囲となるよう
に、更に水が１０〜２００ｇの範囲となるように混合し
調合されたものを使用する。この場合、塩素源として塩
酸及び／又は、塩化アルミニウムが上記範囲になるよう
に添加されるが、２０ｇを越えて添加する場合には添加
効果の向上も見られないばかりか焼成時の廃ガス中の塩
化水素量が多くなり使用設備を腐食したりして好ましく
なく、一方２ｇ未満の添加量では添加効果が不十分であ
る。また、マグネシウム塩としては、塩化マグネシウ
ム、硝酸マグネシウム、硫酸マグネシウム、塩基性炭酸
マグネシウム等の水溶性で且つ酸溶解性の化合物が使用
され、上記範囲になるように添加されるが、０．２ｇ未
満での添加量の場合にはアルミナ表面でのスピネル形成
量が不十分で添加効果が見られず、一方３．０ｇを越え
て添加するときには，終結体の粒界のスピネル層が多く
なり機械的並びに電気的特性が低下するので好ましくな
い。更に、水の添加量は、原料アルミナ中の結晶水や付
着水等の水分量は対象外とし、上記範囲となるように、
例えば塩酸や塩化アルミニウム水溶液での水分或いはマ
グネシウム塩中の結晶水を引いた残り相当量が現実の添
加量となり、その量は原料アルミナを均一な湿潤状態に
するに必要な程度のものである。湿潤処理は、攪拌混合
機に原料アルミナを投入し、それにスピネル化剤水溶液
を添加して１５〜３５℃で３０分〜５時間攪拌混合する
ことによって行い、これによりスラリ−が調製される。
得られたスラリ−は、所望によって１００〜１４０℃で
２〜２０時間乾燥処理する。次いで、該スラリ−または
その乾燥物を焼成容器に充填または充填しない状態でロ
−タリ−キルン・トンネルキルン・シャトルキルン・電
気炉等の焼成炉で１１００〜１４００℃で３０分〜１５
時間保持して焼成する。この場合、スラリ−またはその
乾燥物をシャモット質容器に充填して焼成するときに
は、原料アルミナ中の不純物が表面に拡散して来て後処
理でそれらの不純物を除去し易くなるので、より好まし
い状態となる。この際、１１００℃未満の焼成ではスピ
ネル形成が不十分であり、１４００℃を越えると生成ア
ルミナの一次粒子が成長して大きくなり焼結性が損なわ
れるようになるので好ましくない。焼成後は、所望によ
って、ボ−ルミル・振動ミル等の粉砕機で解砕処理し製
品とする。[0005] It is economically advantageous to use gibbsite-type aluminum hydroxide as a raw material aluminum hydroxide used in the present invention, which is produced by a via method which is industrially mass-produced and available at low cost. The raw material intermediate alumina has an α conversion of 10% or less and a BET specific surface area of 8 to 10 obtained by calcining the intermediate alumina at 500 to 1000 ° C.
It is practical to use 0 m 2 / g of alumina, and a mixture of both can be used as a raw material if desired. Those having an average particle size of 5 to 150 μm are generally used, the purity in terms of alumina is 99.6% by weight or more, the total soda content is 0.05 to 0.4% by weight, and the radioactivity of uranium, thorium, etc. Those having an element content of 2 ppm or less are preferred. Such aluminum hydroxide and / or intermediate alumina (hereinafter, also referred to as “raw material alumina” including both) is wet-treated with an aqueous solution of spinel agent. The aqueous spinel agent solution comprises hydrochloric acid and / or aluminum chloride and a water-soluble and acid-soluble magnesium salt. In this case, hydrochloric acid and / or aluminum chloride activates the surface of the raw material alumina and functions as a blow-over preventing agent during firing of the raw material alumina, while the magnesium salt functions as a spinel agent on the surface of the alumina. . The spinel agent aqueous solution is 1 kg of raw material alumina as a whole.
On the other hand, hydrochloric acid and / or aluminum chloride are used as chloride ions (Cl − ) in the range of 2 to 20 g, and the water-soluble and acid-soluble magnesium salt is 0.2 to 3 in terms of magnesium oxide MgO. Water is further mixed and prepared so as to be in a range of 10 to 200 g, so as to be in a range of 0.0 g. In this case, hydrochloric acid and / or aluminum chloride is added as a chlorine source so as to be within the above range. However, when the amount exceeds 20 g, the effect of addition is not improved, and the waste gas at the time of firing is not improved. Is unfavorable because the amount of hydrogen chloride increases and corrodes the equipment used. On the other hand, if the amount is less than 2 g, the effect of addition is insufficient. Further, as the magnesium salt, a water-soluble and acid-soluble compound such as magnesium chloride, magnesium nitrate, magnesium sulfate, and basic magnesium carbonate is used. In the case of the addition amount, the spinel formation amount on the alumina surface is insufficient and the addition effect is not seen. On the other hand, when the addition amount exceeds 3.0 g, the spinel layer at the grain boundaries of the final body increases and the mechanical effect is increased. In addition, it is not preferable because electrical characteristics are deteriorated. Further, the amount of water to be added is such that the amount of water such as crystallization water and attached water in the raw material alumina is excluded from the target, and is in the above range.
For example, the actual addition amount is the remaining amount after subtracting the water content of hydrochloric acid or aluminum chloride aqueous solution or the water of crystallization in the magnesium salt, and the amount is an amount necessary to bring the raw material alumina into a uniform wet state. The wet treatment is carried out by charging the raw material alumina into a stirring mixer, adding an aqueous solution of a spinel agent thereto, and stirring and mixing at 15 to 35 ° C. for 30 minutes to 5 hours, whereby a slurry is prepared.
The obtained slurry is dried at 100 to 140 ° C. for 2 to 20 hours as required. Next, the slurry or its dried product is filled in a firing vessel or not in a firing furnace such as a rotary kiln, a tunnel kiln, a shuttle kiln or an electric furnace at 1100 to 1400 ° C. for 30 minutes to 15 hours.
Hold for a time and bake. In this case, when the slurry or the dried product thereof is filled in a chamotte container and fired, impurities in the raw material alumina diffuse into the surface and the impurities can be easily removed by a post-treatment, so that a more preferable state. Becomes In this case, if the firing is performed at a temperature lower than 1100 ° C., spinel formation is insufficient. If the firing temperature exceeds 1400 ° C., primary particles of the formed alumina grow and become large, and sinterability is impaired. After firing, if desired, the product is pulverized by a pulverizer such as a ball mill or a vibration mill to obtain a product.
【０００６】更に、好ましくは焼成後の解砕処理前に、
スラリ−流動性の向上処理のための希酸水溶液による洗
浄処理、並びに脱放射性元素処理として希塩基水溶液に
よる洗浄処理を何れか一方またはその双方を行う。希酸
水溶液による洗浄処理は、塩酸・硫酸・硝酸等の鉱酸の
ｐＨ３〜６の水溶液を用い、１５〜８０℃でスラリ−濃
度１００〜５００ｇ／リットルにて３０分〜５時間攪拌
処理して行い、その後は濾過し水洗する。これによっ
て、焼結用グリ−ン体を調製する際の良好なスラリ−流
動性を保持することが容易となる。希塩基水溶液による
洗浄処理は、炭酸ソ−ダ・苛性ソ−ダ・アンモニア等の
ｐＨ８〜１１の水溶液を用い、２５〜１００℃でスラリ
−濃度１００〜５００ｇ／リットルにて３０分〜５時間
攪拌処理して行い、その後は濾過し水洗する。これによ
って、表面から放射性元素が除去される。これらの希酸
水溶液及び希塩基水溶液による洗浄処理は、所望によっ
て、いずれか単独処理のみを施しても良いし、両者を共
に施しても良く、その処理順序も特に問わずいずれが先
でもよい。そして、後処理として濾過・水洗処理を行う
が、水洗に使用する水が工業用水である場合には、汚染
防止のために、使用水に０．１〜２．０ｇ／リットルの
ＥＤＴＡなどのキレ−ト化剤を添加するのが好ましい。
これらの洗浄工程を経た後は、前述のように常法によっ
て適宜乾燥・解砕・篩分け工程を経て製品とされる。[0006] Further, preferably before the crushing treatment after firing,
Either one or both of a washing treatment with a dilute acid aqueous solution for a treatment for improving the fluidity of the slurry and a washing treatment with a dilute base aqueous solution as a deradiation element treatment are performed. The washing treatment with a dilute acid aqueous solution is performed by using an aqueous solution of a mineral acid such as hydrochloric acid, sulfuric acid or nitric acid having a pH of 3 to 6 and stirring at 15 to 80 ° C. at a slurry concentration of 100 to 500 g / l for 30 minutes to 5 hours. After that, it is filtered and washed with water. This makes it easy to maintain good slurry fluidity when preparing the green body for sintering. The washing treatment with a dilute aqueous base solution uses an aqueous solution having a pH of 8 to 11, such as sodium carbonate, caustic soda, and ammonia, and is stirred at 25 to 100 ° C. at a slurry concentration of 100 to 500 g / liter for 30 minutes to 5 hours. The treatment is performed, followed by filtration and washing with water. This removes radioactive elements from the surface. The washing treatment with the dilute acid aqueous solution and the dilute base aqueous solution may be performed alone or in combination with each other as desired, and may be performed in any order, regardless of the processing order. Then, filtration and washing are performed as a post-treatment. When the water used for washing is industrial water, clean water such as EDTA of 0.1 to 2.0 g / liter is used to prevent contamination. It is preferred to add a toning agent.
After passing through these washing steps, a product is obtained through appropriate drying, crushing and sieving steps by a conventional method as described above.
【０００７】このようにして得られたアルミナは、表面
にスピネル層を０．０７〜１．０５重量％形成した平均
粒径０．４〜０．７μｍの易焼結性アルミナであって、
１５５０〜１６００℃でも容易に焼結する特性を保有す
る。また、焼成後に希酸水溶液で処理した場合には良好
なスラリ−流動性を保持するものとなり、成形加工作業
が容易となると共により高密度の焼結体が製造されるよ
うになる。他方、焼成後に希塩基水溶液で処理した場合
には放射性元素が除去されてＩＣ基板に適用した場合に
α線による誤作動の発生がないものが得られるようにな
り、その双方の洗浄処理を行うときには双方の効果が共
に発揮される。The alumina thus obtained is an easily sinterable alumina having an average particle diameter of 0.4 to 0.7 μm having a spinel layer formed on the surface in an amount of 0.07 to 1.05% by weight.
It retains the property of being easily sintered even at 1550 to 1600 ° C. Further, when treated with a dilute acid aqueous solution after sintering, good slurry fluidity is maintained, so that a molding process is facilitated and a higher density sintered body is manufactured. On the other hand, when treated with a dilute aqueous base solution after baking, radioactive elements are removed, and when applied to an IC substrate, a product that does not cause malfunction due to α-rays can be obtained. Sometimes both effects are exerted together.
【０００８】[0008]
【作用】本願発明のアルミナは、各粒子単位で主として
表層にスピネル（ＭｇＡｌ2 Ｏ4 ）が存在するので、焼
結時に焼結体の全体で均一にアルミナの異常粒成長が抑
制されるので、閉気孔の発生や不均一な収縮等が防止さ
れ、例えば１５５０〜１６００℃の焼結温度で焼結密度
が３．９２ｇ／ｃｍ3 以上の焼結体が安定して得られ
る。また、上述の第一の製造方法によりスピネル化剤水
溶液で湿潤・焼成処理する時には、付着する塩素イオン
が水酸化アルミニウムの４００〜５００℃での脱水によ
る急激な水蒸気の発生による焼成容器からの吹き溢れの
発生を抑制する効果を果たすと共にアルミナ表面を活性
にしてマグネシウム塩との反応性を高め、マグネシウム
塩がその活性化された水酸化アルミニウム及び中間アル
ミナの表面での化学反応が促進されスピネル層が適切に
形成される。また、焼成に際して、容器に充填せずにそ
のままの状態で焼成する場合と比較して、シャモット質
容器に充填して焼成することは、それによって生成アル
ミナ表面のナトリウムが揮散し易くなるのでより好まし
いものとなる。更に、スピネル層の形成後に希酸洗浄処
理すると、形成されたスピネル層が溶解されることな
く、ソ−ダ分等の酸溶解性不純物が除去されると共に、
表面の中間アルミナ（γ・δ・θ・κ・χ）相が予め十
分に再水和されるので、生スラリ−の調製時に再水和に
よるスラリ−粘度の上昇が無くなるために、スラリ−流
動性の経時的な変化がなく安定化し成形加工操作を安易
なものとなる。一方、スピネル層の形成後に希塩基洗浄
処理する場合には、形成されたスピネル層が溶解される
ことなくアルミナ表面に拡散して来た放射性元素が容易
に溶解除去されることになる。In the alumina of the present invention, spinel (MgAl 2 O 4 ) mainly exists in the surface layer in each particle unit, so that abnormal grain growth of alumina is suppressed uniformly throughout the sintered body during sintering. The generation of closed pores and uneven shrinkage are prevented, and a sintered body having a sintering density of 3.92 g / cm 3 or more can be stably obtained at a sintering temperature of, for example, 1550 to 1600 ° C. Further, when performing the wetting and baking treatment with the aqueous spinel agent solution by the above-described first manufacturing method, the chlorine ions to be adhered are blown out of the baking vessel by the rapid generation of water vapor due to the dehydration of aluminum hydroxide at 400 to 500 ° C. It has the effect of suppressing the occurrence of overflow and activates the alumina surface to increase the reactivity with the magnesium salt. The magnesium salt promotes the chemical reaction on the surface of the activated aluminum hydroxide and the intermediate alumina, and the spinel layer Is formed appropriately. In addition, during firing, compared to the case of firing in the same state without filling the container, filling and firing in a chamotte container is more preferable because sodium on the surface of the formed alumina is easily volatilized thereby. It will be. Furthermore, when the dilute acid cleaning treatment is performed after the formation of the spinel layer, the formed spinel layer is not dissolved, so that acid-soluble impurities such as soda are removed, and
Since the intermediate alumina (γ, δ, θ, κ, χ) phase on the surface is sufficiently rehydrated in advance, the slurry viscosity does not increase due to rehydration during the preparation of the raw slurry. The properties are not changed with time, and the molding operation is easy. On the other hand, when the dilute base cleaning treatment is performed after the formation of the spinel layer, the radioactive element diffused on the alumina surface without dissolving the formed spinel layer is easily dissolved and removed.
【０００９】[0009]
【実施例】以下に実施例・比較例により本発明をより具
体的に説明するが、これに限定されるものではない。ま
た、以下の実施例・比較例においては、共通して下記の
条件で試料調製及びその特性測定を行った。 （１）試料調製 原料水酸化アルミニウムとして、 全ソ−ダ（Ｎａ2 Ｏとして） ０．１８重量％ その他の金属不純物（酸化物として） ０．０５重量％ 放射性元素（Ｕとして） ０．２ｐｐｍ 付着水分 ８．０重量％ であり平均粒度が７０μｍ（篩粒度）のバイヤ−法水酸
化アルミニウムを共通して用いた。また、原料中間アル
ミナとしては、上記水酸化アルミニウムを１０００℃で
１０時間焼成して得たＢＥＴ比表面積が２０ｍ2 ／ｇで
α化率０％のものを使用した。これらの所定量の原料ア
ルミナをヘンシェルミキサ−に投入し、それに別途調製
したスピネル化剤水溶液を所定量加えて１時間混練し湿
潤処理した。得られたスラリ−を１３０℃で１０時間乾
燥処理した後シャモット質容器に充填し、電気炉にて１
２００℃で５時間保持して焼成処理し、α−アルミナを
得た。得られたアルミナを別途、酸及び塩基を用いて所
定条件での洗浄処理を施した後、２００℃で１２時間乾
燥処理して、表面処理したα−アルミナを得た。 （２）特性測定 上記によって得られたα−アルミナから１ｋｇを分取し
たものを、内容積５．４リットルのポットを有する振動
ボ−ルミルで２０ｍｍφのアルミナボ−ル７５００ｇを
入れた状態で１６時間解砕処理し、特性測定用試料とし
た。また、特性の測定条件は以下の通りである。 １）スラリ−粘度：測定用α−アルミナ粉末９００ｇを
純水１６２ｇ、分散剤としてポリアクリル酸重合体（日
本化薬社製商品名カヤディスパ−Ｃ−７２）９ｇ、結合
剤としてアクリル酸エステル共重合体（日本化薬社製商
品名カヤバインダ−ＫＳ−９００）２７ｇ及びセラミッ
クスボ−ル２７０ｇを用いて振動ボ−ルミルで２０時間
混練した後、取り出して室温で２４時間放置したものを
ビスコテスタ−で粘度測定した。 ２）焼結特性：上記スラリ−粘度測定用に調製したスラ
リ−を用いて、成形圧力３５０ｋｇ／ｃｍ2 で２０×４
０×９ｍｍの板状に成形し、電気炉で所定条件下で焼結
処理した後、焼結密度を測定した。 ３）ウラン含有量：ｉｓｏ−ｎ−オクチルアミン抽出し
たものをフッ化ナトリウム蛍光光度法で測定した。The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but it should not be construed that the invention is limited thereto. In the following examples and comparative examples, a sample was prepared and its characteristics were measured under the following conditions. (1) Sample preparation As raw aluminum hydroxide, total soda (as Na 2 O) 0.18% by weight Other metal impurities (as oxide) 0.05% by weight Radioactive element (as U) 0.2ppm adhered The aluminum hydroxide having a water content of 8.0% by weight and an average particle size of 70 μm (sieve particle size) was commonly used. As the raw material intermediate alumina, one having a BET specific surface area of 20 m 2 / g and an α conversion of 0% obtained by firing the above-mentioned aluminum hydroxide at 1000 ° C. for 10 hours was used. A predetermined amount of the raw material alumina was charged into a Henschel mixer, and a separately prepared aqueous solution of a spinel agent was added thereto, kneaded for 1 hour, and wet-treated. After drying the obtained slurry at 130 ° C. for 10 hours, the slurry was filled in a chamotte container and placed in an electric furnace.
The mixture was calcined at 200 ° C. for 5 hours to obtain α-alumina. The obtained alumina was separately subjected to a washing treatment under predetermined conditions using an acid and a base, and then dried at 200 ° C. for 12 hours to obtain surface-treated α-alumina. (2) Characteristic measurement A 1 kg sample of the α-alumina obtained as described above was fractionated for 16 hours in a vibrating ball mill having a 5.4 liter internal volume, in which 7500 g of a 20 mmφ alumina ball was put. It was crushed and used as a sample for property measurement. The measurement conditions of the characteristics are as follows. 1) Slurry-viscosity: 900 g of α-alumina powder for measurement was 162 g of pure water, 9 g of a polyacrylic acid polymer (Kayadisper-C-72, manufactured by Nippon Kayaku Co., Ltd.) as a dispersant, and acrylic acid ester copolymer as a binder. After kneading with a vibration ball mill for 20 hours using 27 g of the coalesced product (Kaya Binder-KS-900 manufactured by Nippon Kayaku Co., Ltd.) and 270 g of ceramic balls, the mixture was taken out and left at room temperature for 24 hours to obtain a viscosity using a viscometer. It was measured. 2) Sintering characteristics: 20 × 4 at a molding pressure of 350 kg / cm 2 using the slurry prepared for viscosity measurement.
After shaping into a plate shape of 0 × 9 mm and sintering under a predetermined condition in an electric furnace, the sintering density was measured. 3) Uranium content: Iso-n-octylamine extracted was measured by sodium fluoride fluorometry.
【００１０】実施例１ 上記の水酸化アルミニウムを１０００ｇ用意し、３５．
５重量％塩酸１７．４ｇと硫酸マグネシウム１．１ｇを
２００ｇの純水に添加して調製したスピネル化剤水溶液
を用いて、上記処理条件で処理して、α−アルミナを得
た。 実施例２ 上記の水酸化アルミニウムを１０００ｇ用意し、塩化ア
ルミニウム（６水塩）１３．７ｇと硝酸マグネシウム
（６水塩）２．３ｇを２００ｇの純水に添加して調製し
たスピネル化剤水溶液を用いて、上記処理条件で処理し
て、α−アルミナを得た。 実施例３ 上記の水酸化アルミニウムを１０００ｇ用意し、塩化ア
ルミニウム（６水塩）１３．７ｇと塩化マグネシウム
（６水塩）１．８ｇを２００ｇの純水に添加して調製し
たスピネル化剤水溶液を用いて、上記処理条件で処理し
て、α−アルミナを得た。 実施例４ 上記の水酸化アルミニウムを１０００ｇ用意し、３５．
５重量％塩酸１７．４ｇと塩基性炭酸マグネシウム（３
水塩）３．３ｇを２００ｇの純水に添加して調製したス
ピネル化剤水溶液を用いて、上記処理条件で処理して、
α−アルミナを得た。 実施例５ 上記の水酸化アルミニウムを１０００ｇ用意し、塩化ア
ルミニウム（６水塩）１３．７ｇと塩化マグネシウム
（６水塩）１．８ｇを２００ｇの純水に添加して調製し
たスピネル化剤水溶液を用いて、上記処理条件で処理し
て、α−アルミナを得た。Example 1 1000 g of the above aluminum hydroxide was prepared, and 35.
An aqueous solution of spinel agent prepared by adding 17.4 g of 5% by weight hydrochloric acid and 1.1 g of magnesium sulfate to 200 g of pure water was treated under the above treatment conditions to obtain α-alumina. Example 2 1000 g of the above aluminum hydroxide was prepared, and 13.7 g of aluminum chloride (hexahydrate) and 2.3 g of magnesium nitrate (hexahydrate) were added to 200 g of pure water. And treated under the above treatment conditions to obtain α-alumina. Example 3 1000 g of the above aluminum hydroxide was prepared, and 13.7 g of aluminum chloride (hexahydrate) and 1.8 g of magnesium chloride (hexahydrate) were added to 200 g of pure water. And treated under the above treatment conditions to obtain α-alumina. Example 4 1000 g of the above aluminum hydroxide was prepared.
17.4 g of 5% by weight hydrochloric acid and basic magnesium carbonate (3
(Salt) 3.3 g was added to 200 g of pure water, and the mixture was treated under the above-mentioned treatment conditions using an aqueous solution of spinel agent prepared.
α-alumina was obtained. Example 5 1000 g of the above aluminum hydroxide was prepared, and 13.7 g of aluminum chloride (hexahydrate) and 1.8 g of magnesium chloride (hexahydrate) were added to 200 g of pure water. And treated under the above treatment conditions to obtain α-alumina.
【００１１】比較例１ 上記の水酸化アルミニウムを１０００ｇ用意し、塩化ア
ルミニウム（６水塩）１３．７ｇのみを２００ｇの純水
に添加して調製した水溶液を用いて、上記処理条件で処
理してα−アルミナを得た。 比較例２ 比較例１で得たα−アルミナを振動ボ−ルミルで解砕す
るときに、塩基性炭酸マグネシウム（３水塩）を酸化マ
グネシウムとして０．０５５重量％になるように添加し
て、α−アルミナにマグネシウム塩が混合された粉末を
比較材として調製した。 比較例３ 実施例１において、スピネル化剤水溶液中の硫酸マグネ
シウム量を１１．０ｇとした以外は同様に処理した。以
上の結果得られた実施例及び比較例によるα−アルミナ
を用いて、それ自体の性状とその焼結特性を、上記条件
で測定した。その結果を表１に示す。Comparative Example 1 The above-mentioned aluminum hydroxide was prepared in an amount of 1000 g, and only 13.7 g of aluminum chloride (hexahydrate) was added to 200 g of pure water. α-alumina was obtained. Comparative Example 2 When the α-alumina obtained in Comparative Example 1 was pulverized with a vibration ball mill, basic magnesium carbonate (trihydrate) was added so as to be 0.055% by weight as magnesium oxide. Powder in which a magnesium salt was mixed with α-alumina was prepared as a comparative material. Comparative Example 3 The same treatment as in Example 1 was carried out except that the amount of magnesium sulfate in the aqueous solution of the spinel agent was changed to 11.0 g. Using the α-alumina according to the examples and comparative examples obtained as a result of the above, the properties themselves and the sintering characteristics thereof were measured under the above conditions. Table 1 shows the results.
【００１２】[0012]
【表１】 [Table 1]
【００１３】実施例６ 実施例３で得られたα−アルミナ２５０ｇを、１リット
ルの水に３５．５重量％塩酸２８．２ｇを添加して調製
した希塩酸（ｐＨ３）中に投入し、２５℃で１時間攪拌
処理し濾過した後、３倍容量の水で通水洗浄し、続いて
２００℃で１２時間乾燥処理した。 実施例７ 実施例３で得られたα−アルミナ２５０ｇを、１リット
ルの水に炭酸ソ−ダ１５．０ｇを添加して調製した希塩
基（ｐＨ１１）中に投入し、６０℃で１時間攪拌処理し
濾過した後、３倍容量の水で通水洗浄し、続いて２００
℃で１２時間乾燥処理した。 実施例８ 実施例６で希塩酸処理し水洗した段階のα−アルミナ２
５０ｇを、引き続いて１リットルの水に炭酸ソ−ダ１
５．０ｇを添加して調製した希塩基（ｐＨ１１）中に投
入し、６０℃で１時間攪拌処理し濾過した後、３倍容量
の水で通水洗浄し、続いて２００℃で１２時間乾燥処理
した。Example 6 250 g of the α-alumina obtained in Example 3 was put into dilute hydrochloric acid (pH 3) prepared by adding 28.2 g of 35.5% by weight hydrochloric acid to 1 liter of water, and the solution was added at 25 ° C. The mixture was stirred for 1 hour, filtered, washed with 3 times volume of water, and dried at 200 ° C. for 12 hours. Example 7 250 g of the α-alumina obtained in Example 3 was put into a dilute base (pH 11) prepared by adding 15.0 g of sodium carbonate to 1 liter of water, and stirred at 60 ° C. for 1 hour. After treatment and filtration, the product was washed by passing it through with three times the volume of water, followed by 200 times.
Drying was performed at 12 ° C. for 12 hours. Example 8 α-Alumina 2 at the stage of dilute hydrochloric acid treatment and washing with water in Example 6
50 g are subsequently added to 1 liter of water with sodium carbonate 1
It was poured into a diluted base (pH 11) prepared by adding 5.0 g, stirred at 60 ° C. for 1 hour, filtered, washed with 3 volumes of water, and then dried at 200 ° C. for 12 hours. Processed.
【００１４】比較例４ 実施例６において、３５．５重量％塩酸の添加量を１４
１ｇとして、同様に処理した。 比較例５ 実施例６において、希塩酸での洗浄に代えて、水洗のみ
として、以降同様に処理した。以上の結果得られた実施
例及び比較例によるα−アルミナを用いて、それ自体の
性状とその焼結特性を、上記条件で測定した。その結果
を表２に示す。Comparative Example 4 In Example 6, the amount of 35.5% by weight hydrochloric acid added was 14
1 g was treated similarly. Comparative Example 5 The procedure of Example 6 was repeated, except that washing with dilute hydrochloric acid was used instead of washing with water. Using the α-alumina according to the examples and comparative examples obtained as a result of the above, the properties themselves and the sintering characteristics thereof were measured under the above conditions. Table 2 shows the results.
【００１５】[0015]
【表２】 [Table 2]
【００１６】[0016]
【発明の効果】本願発明は、上述のように易焼結性アル
ミナとその製造方法に関するものであって、下記のよう
な効果が発揮され、工業的に極めて有用なものである。 （１）本願発明のアルミナは、その表面にスピネル層が
形成されているので、個々の粒子単位で易焼結性とな
り、比較的低温の１５５０〜１６００℃の焼結温度でも
３．９２ｇ／ｃｍ3 以上の焼結密度の焼結体を安定的に
得ることが出来る。 （２）本願発明の第一の製造法によるときには、特定の
スピネル化剤水溶液を使用するので、焼成過程での焼成
容器からの粉末の吹き溢れ現象の発生を適切に抑制しな
がらスピネル化反応を発現させて、易焼結性アルミナを
経済的に得ることが出来る。 （３）また、第一の製造法での焼成工程に引き続いて希
酸洗浄を付加することによって、アルミナ焼結体を製造
する工程で生スラリ−を形成する時にスラリ−流動性が
経時的に変化しないので、例えば８５重量％程度までの
高濃度スラリ−を調製し得るようになり、高密度で例え
ば３０ｃｍ角レベルの大型の成形体の製造がより容易と
なる。また、これによって寸法精度の良好な焼結体が容
易に得られると共に、表面に拡散してきたソ−ダ分や鉄
分等が希酸洗浄の際に溶解除去されるので、焼結体の電
気特性も副次的に改善される。 （４）或いは、第一の製造法での焼成工程に引き続いて
希塩基洗浄を付加する時には、表面に拡散してきた放射
性元素が溶解除去されるので、本処理を施したアルミナ
を用いた焼結体はＩＣ基板に適用するときにα線による
誤作動の発生がないようになる。それ故、ＩＣ基板用原
料アルミナ源として、特に従来のような高純度のものの
使用が望まれることなく、安価なアルミナ源の適用が可
能となる。 （５）更に、第一の製造法での焼成工程に引き続いて希
酸洗浄と希塩基洗浄との両工程を付加することによっ
て、個々の工程による効果を同時に発現させることが出
来る。Industrial Applicability The present invention relates to an easily sinterable alumina and a method for producing the same as described above, and has the following effects and is extremely useful industrially. (1) Since the spinel layer is formed on the surface of the alumina of the present invention, it becomes easy to sinter in units of individual particles, and 3.92 g / cm even at a relatively low sintering temperature of 1550 to 1600 ° C. A sintered body having a sintered density of 3 or more can be stably obtained. (2) According to the first production method of the present invention, since a specific aqueous solution of spinel agent is used, the spinelization reaction is appropriately suppressed while the powder overflows from the firing vessel during the firing process. It is possible to economically obtain easily sinterable alumina. (3) Further, by adding a dilute acid washing subsequent to the firing step in the first manufacturing method, the slurry fluidity may change with time when forming the raw slurry in the step of manufacturing the alumina sintered body. Since it does not change, a high-concentration slurry of, for example, up to about 85% by weight can be prepared, and it becomes easier to manufacture a large-sized compact having a high density, for example, a 30 cm square level. In addition, a sintered body having good dimensional accuracy can be easily obtained by this, and soda and iron which have diffused to the surface are dissolved and removed at the time of dilute acid cleaning, so that the electrical properties of the sintered body can be improved. Is also improved as a side effect. (4) Alternatively, when dilute base washing is added subsequent to the firing step in the first production method, radioactive elements diffused to the surface are dissolved and removed, so sintering using the alumina that has been subjected to this treatment is performed. The body is free from α-ray malfunction when applied to an IC substrate. Therefore, it is possible to use an inexpensive alumina source without particularly demanding the use of a conventional high-purity alumina source as a raw material alumina source for IC substrates. (5) Further, by adding both the dilute acid cleaning step and the dilute base cleaning step subsequent to the baking step in the first production method, the effects of the individual steps can be simultaneously exhibited.
Claims (3)
１．０５重量％形成したアルミナであることを特徴とす
る易焼結性アルミナ。1. A spinel layer having a thickness of 0.07 to 1.0
An easily sinterable alumina, which is formed with 1.05% by weight of alumina.
ミナを塩酸及び／又は塩化アルミニウムと水溶性で且つ
酸溶解性のマグネシウム塩とから成るスピネル化剤水溶
液で湿潤してＭｇＯ換算０．０２〜０．３重量％のマグ
ネシウム塩を担持させた後、所望によってシャモット質
容器に充填した状態としてから、１０００〜１４００℃
で焼成することを特徴とする易焼結性アルミナの製造方
法。2. An aluminum hydroxide and / or an intermediate alumina is wetted with an aqueous solution of a spinel agent comprising hydrochloric acid and / or aluminum chloride and a water-soluble and acid-soluble magnesium salt to obtain a 0.02-0. After supporting 3% by weight of a magnesium salt, if necessary, after filling in a chamotte container, 1000-1400 ° C.
A method for producing easily sinterable alumina, characterized by firing.
は希塩基水溶液で洗浄処理することを特徴とする請求項
２に記載の易焼結性アルミナの製造方法。3. The method for producing easily sinterable alumina according to claim 2, wherein after the calcination, a washing treatment is performed with a dilute acid aqueous solution and / or a dilute base aqueous solution.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4312657A JP2658776B2 (en) | 1992-10-29 | 1992-10-29 | Sinterable alumina and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4312657A JP2658776B2 (en) | 1992-10-29 | 1992-10-29 | Sinterable alumina and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06135714A JPH06135714A (en) | 1994-05-17 |
| JP2658776B2 true JP2658776B2 (en) | 1997-09-30 |
Family
ID=18031856
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4312657A Expired - Lifetime JP2658776B2 (en) | 1992-10-29 | 1992-10-29 | Sinterable alumina and method for producing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2658776B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3273773B2 (en) | 1999-08-12 | 2002-04-15 | イビデン株式会社 | Ceramic heater for semiconductor manufacturing / inspection equipment, electrostatic chuck for semiconductor manufacturing / inspection equipment and chuck top for wafer prober |
| CN115254025B (en) * | 2022-08-19 | 2024-04-05 | 常州大学 | Preparation method of printing and dyeing sludge dehydrating agent and method for conditioning printing and dyeing sludge by using same |
-
1992
- 1992-10-29 JP JP4312657A patent/JP2658776B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06135714A (en) | 1994-05-17 |
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