JPH0362648B2 - - Google Patents
Info
- Publication number
- JPH0362648B2 JPH0362648B2 JP57190073A JP19007382A JPH0362648B2 JP H0362648 B2 JPH0362648 B2 JP H0362648B2 JP 57190073 A JP57190073 A JP 57190073A JP 19007382 A JP19007382 A JP 19007382A JP H0362648 B2 JPH0362648 B2 JP H0362648B2
- Authority
- JP
- Japan
- Prior art keywords
- water
- aluminum hydroxide
- alumina
- particle size
- powder
- 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
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 claims description 16
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 16
- 229910001593 boehmite Inorganic materials 0.000 claims description 12
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 claims description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims description 8
- 238000010304 firing Methods 0.000 claims description 6
- 150000001732 carboxylic acid derivatives Chemical class 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 239000002245 particle Substances 0.000 description 18
- 239000000843 powder Substances 0.000 description 13
- YASYEJJMZJALEJ-UHFFFAOYSA-N Citric acid monohydrate Chemical compound O.OC(=O)CC(O)(C(O)=O)CC(O)=O YASYEJJMZJALEJ-UHFFFAOYSA-N 0.000 description 8
- 229960002303 citric acid monohydrate Drugs 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 7
- 239000011734 sodium Substances 0.000 description 7
- 239000000725 suspension Substances 0.000 description 5
- UIIMBOGNXHQVGW-UHFFFAOYSA-N sodium;hydron;carbonate Chemical compound [Na+].OC(O)=O UIIMBOGNXHQVGW-UHFFFAOYSA-N 0.000 description 4
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- IPCSVZSSVZVIGE-UHFFFAOYSA-N hexadecanoic acid Chemical compound CCCCCCCCCCCCCCCC(O)=O IPCSVZSSVZVIGE-UHFFFAOYSA-N 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N oxalic acid group Chemical group C(C(=O)O)(=O)O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 238000004131 Bayer process Methods 0.000 description 2
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 2
- GCAIEATUVJFSMC-UHFFFAOYSA-N benzene-1,2,3,4-tetracarboxylic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C(C(O)=O)=C1C(O)=O GCAIEATUVJFSMC-UHFFFAOYSA-N 0.000 description 2
- UJMDYLWCYJJYMO-UHFFFAOYSA-N benzene-1,2,3-tricarboxylic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1C(O)=O UJMDYLWCYJJYMO-UHFFFAOYSA-N 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 2
- 229910052573 porcelain Inorganic materials 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 229910018626 Al(OH) Inorganic materials 0.000 description 1
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 1
- 235000021314 Palmitic acid Nutrition 0.000 description 1
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 description 1
- -1 aromatic dicarboxylic acids Chemical class 0.000 description 1
- KDYFGRWQOYBRFD-NUQCWPJISA-N butanedioic acid Chemical compound O[14C](=O)CC[14C](O)=O KDYFGRWQOYBRFD-NUQCWPJISA-N 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 229960004106 citric acid Drugs 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 150000001991 dicarboxylic acids Chemical class 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000001027 hydrothermal synthesis Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000012778 molding material Substances 0.000 description 1
- WQEPLUUGTLDZJY-UHFFFAOYSA-N n-Pentadecanoic acid Natural products CCCCCCCCCCCCCCC(O)=O WQEPLUUGTLDZJY-UHFFFAOYSA-N 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 239000001509 sodium citrate Substances 0.000 description 1
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000001384 succinic acid Substances 0.000 description 1
- 239000011975 tartaric acid Substances 0.000 description 1
- 235000002906 tartaric acid Nutrition 0.000 description 1
- 150000000000 tetracarboxylic acids Chemical class 0.000 description 1
- 150000003628 tricarboxylic acids Chemical class 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Description
【発明の詳細な説明】
本発明は、易焼結性アルミナの製造方法に関す
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing easily sinterable alumina.
近年、電子部品用磁器、内燃機関の点火栓碍子
等の原料あるいは触媒担体の原料として、高アル
ミナ質材料が多量に使用されているが、その原料
であるアルミナは、成形後高密度（緻密）に焼結
（以下「易焼結性」と呼ぶ）させる為に、粒子は
1μｍ以下の微粒子で出来るだけ粒度の揃つたも
のが要求され、且つアルミナに含有されるNa2Ｏ
は電気絶縁性や耐熱性を低下させたり、触媒担体
としての強度を低下させる為、出来る限りその含
有量を少なくすることが要求されている。 In recent years, a large amount of high alumina materials have been used as raw materials for porcelain for electronic parts, spark plug insulators for internal combustion engines, and catalyst carriers, but the raw material, alumina, has a high density (dense) after forming. In order to sinter (hereinafter referred to as "easy sinterability"), the particles
Fine particles of 1 μm or less with as uniform a particle size as possible are required, and Na 2 O contained in alumina is required.
It is required to reduce the content as much as possible because it lowers electrical insulation properties and heat resistance, and lowers the strength as a catalyst carrier.
現在、工業的に安価、多量に生産されているア
ルミナは、バイヤー法によつて製造された水酸化
アルミニウムを焼成することによつて製造させて
いる為、工程上、通常0.2〜0.4重量％のNa2Ｏが
含有され、そのままでは上記目的に使用すること
は出来ない。 Alumina, which is currently produced industrially at low cost and in large quantities, is produced by firing aluminum hydroxide produced by the Bayer process, so it is usually produced at a concentration of 0.2 to 0.4% by weight due to the process. It contains Na 2 O and cannot be used as is for the above purpose.
Na2Ｏの含有量を低減する方法として、水酸化
アルミニウムの水性スラリーをオートクレーブ中
で177℃以上で処理してベーマイト化し、脱水後
水洗する方法（USP2774744、USP3628914）が
提案されている。この方法は、水酸化アルミニウ
ムがベーマイトに転移する際に、水酸化アルミニ
ウムの結晶中あるいは結晶粒界中に存在するソー
ダが放出される為、水洗のみで容易にNa2Ｏの含
有量を低減することが可能である。しかし、ベー
マイトが結晶性の良い大粒子に成長する為、生成
したベーマイトを焼成して製造したアルミナも５
〜50μｍ程度の大粒径となり、目的とする易焼結
性のアルミナが得られず、このアルミナを成形
後、焼結を行なつても高密度化しない為、高強
度、高耐摩耗性の絶縁材料等の成形材料を得るこ
とが出来なかつた。 As a method for reducing the content of Na 2 O, a method has been proposed in which an aqueous slurry of aluminum hydroxide is treated at 177° C. or higher in an autoclave to form boehmite, and the slurry is dehydrated and washed with water (USP 2774744, USP 3628914). In this method, when aluminum hydroxide transforms into boehmite, the soda present in the aluminum hydroxide crystals or grain boundaries is released, so the Na 2 O content can be easily reduced by simply washing with water. Is possible. However, since boehmite grows into large particles with good crystallinity, alumina produced by firing the boehmite produced also has a
The particle size becomes large, about ~50 μm, and the desired alumina with easy sinterability cannot be obtained. Even if this alumina is formed and sintered, it does not become denser, so it is difficult to obtain high strength and high wear resistance. It was not possible to obtain molding materials such as insulating materials.
かかる事情に鑑み、本発明者らは鋭意検討した
結果、水中に分散させた水酸化アルミニウムを加
熱加圧下処理しベーマイトを得る際に、２個以上
のカルボキシル基を有する水溶性カルボン酸を添
加することにより、小粒径で均一な粒度分布をも
つた易焼結性で、且つ、低ソーダ含量のアルミナ
が得られることを見い出し、本発明を完成するに
至つた。 In view of these circumstances, the inventors of the present invention have conducted intensive studies and found that a water-soluble carboxylic acid having two or more carboxyl groups is added when aluminum hydroxide dispersed in water is treated under heat and pressure to obtain boehmite. The inventors have discovered that, by doing so, it is possible to obtain alumina having a small particle size, a uniform particle size distribution, easy sinterability, and a low soda content, and have completed the present invention.
すなわち本発明の要旨は、水中に分散させた水
酸化アルミニウムと２個以上のカルボキシル基を
有する水溶性カルボン酸を加熱加圧下処理し、ベ
ーマイトを得た後、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に存する。 That is, the gist of the present invention is to provide an easy-to-sinter method characterized in that aluminum hydroxide dispersed in water and a water-soluble carboxylic acid having two or more carboxyl groups are treated under heat and pressure to obtain boehmite, which is then fired. The invention consists in a method for producing condensed alumina.
以下、本発明を説明する。 The present invention will be explained below.
本発明で使用する水酸化アルミニウムは特に限
定されるものではなく、例えば、バイヤー法工程
より得られた水酸化アルミニウム等が使用でき
る。その粒径はあまり大きすぎるとベーマイト化
に高温、長時間の処理が必要となり、又小さすぎ
ると取扱いが困難となる為、通常0.1μｍ以上、好
ましくは0.5〜50μｍの水酸化アルミニウムが好ま
しい。 The aluminum hydroxide used in the present invention is not particularly limited, and for example, aluminum hydroxide obtained from the Bayer process can be used. If the particle size is too large, high-temperature and long-time treatment will be required to turn it into boehmite, and if it is too small, it will be difficult to handle, so aluminum hydroxide with a particle size of usually 0.1 μm or more, preferably 0.5 to 50 μm is preferred.
２個以上のカルボキシル基を有する水溶性カル
ボン酸としては、例えば、シユウ酸、コハク酸、
酒石酸、マロン酸等の鎖式ジカルボン酸、フタル
酸等の芳香族ジカルボン酸、クエン酸、ベンゼン
トリカルボン酸等のトリカルボン酸、ベンゼンテ
トラカルボン酸等のテトラカルボン酸等が挙げら
れる。 Examples of water-soluble carboxylic acids having two or more carboxyl groups include oxalic acid, succinic acid,
Examples include chain dicarboxylic acids such as tartaric acid and malonic acid, aromatic dicarboxylic acids such as phthalic acid, tricarboxylic acids such as citric acid and benzenetricarboxylic acid, and tetracarboxylic acids such as benzenetetracarboxylic acid.
添加量は、水酸化アルミニウムに対し0.5〜30
重量％、好ましくは２〜20重量％である。 The amount added is 0.5 to 30 per aluminum hydroxide.
% by weight, preferably 2-20% by weight.
上記水酸化アルミニウムと２個以上のカルボキ
シル基を有する水溶性カルボン酸を水に分散さ
せ、加熱加圧下処理しベーマイトを得る。 The above aluminum hydroxide and a water-soluble carboxylic acid having two or more carboxyl groups are dispersed in water and treated under heat and pressure to obtain boehmite.
水量は、固形分に対して１〜50重量倍、好まし
くは２〜30重量倍である。 The amount of water is 1 to 50 times the solid content, preferably 2 to 30 times the weight.
水熱反応の条件は、使用する水酸化アルミニウ
ムの粒径によつて異なるが、通常、150〜280℃、
５〜65Kg／cm2Ｇで0.1〜20時間、好ましくは170〜
250℃、８〜40Kg／cm2Ｇで0.5〜10時間の範囲で行
なえばよい。 The conditions for the hydrothermal reaction vary depending on the particle size of the aluminum hydroxide used, but are usually 150-280℃,
5-65Kg/ cm2G for 0.1-20 hours, preferably 170-20 hours
The heating may be carried out at 250° C. and 8 to 40 kg/cm 2 G for 0.5 to 10 hours.
この様にして得られたベーマイト懸濁液を常法
通り水洗、乾燥した後、500℃以上、好ましくは、
1100〜1500℃の温度で焼成することにより0.05重
量％以下の低ソーダ含量で、粒径1μｍ以下、特
に0.1〜0.8μｍの易焼結性のアルミナが容易に得
られる。 The boehmite suspension thus obtained is washed with water and dried in a conventional manner, and then heated to a temperature of 500°C or higher, preferably.
By firing at a temperature of 1100 to 1500°C, easily sinterable alumina with a particle size of 1 μm or less, particularly 0.1 to 0.8 μm, can be easily obtained with a low soda content of 0.05% by weight or less.
この易焼結性アルミナを更に成形後、アルミナ
製造時の焼成温度以上に焼結すれば高密度なアル
ミナ成形体が得られ、電子部品用磁器、内燃機関
の点火栓碍子、切削工具、医療部品等に適用でき
る。 If this easily sinterable alumina is further shaped and sintered at a temperature higher than the firing temperature used for alumina production, a high-density alumina molded body can be obtained, which can be used to produce porcelain for electronic parts, ignition plug insulators for internal combustion engines, cutting tools, and medical parts. It can be applied to etc.
２個以上のカルボキシル基を有する水溶性カル
ボン酸の添加が効果を発現する理由は必ずしも明
確ではないが、その理由の一つとして、PHを低下
させることにより水酸化アルミニウムの溶解度を
上昇させ、核生成速度を速くする事、並びに水酸
アルミニウムあるいはベーマイトのある特定の結
晶面に吸着して、いわゆる媒晶効果の役割を演じ
ることにより、粒子を微細にしていることが考え
られる。 The reason why the addition of a water-soluble carboxylic acid having two or more carboxyl groups is effective is not necessarily clear, but one reason is that by lowering the pH, it increases the solubility of aluminum hydroxide and It is conceivable that the particles are made finer by increasing the production rate and by adsorbing to a certain crystal face of aluminum hydroxide or boehmite and playing the role of the so-called mediocrystal effect.
以上説明した方法により得られるアルミナは平
均粒径1μｍ以下の微細で粒径の揃つた低ソーダ
含量品で、通常の乾燥、焼成条件で凝集すること
がない為、粉砕工程が不要となり、エネルギーの
消費量が少なく且つ、粉砕工程中の不純物の汚染
を防止出来るといつた利点を有するもので、その
工業的価値は大なるものである。 The alumina obtained by the method explained above is a fine, uniformly sized product with a low soda content, with an average particle size of 1 μm or less, and does not agglomerate under normal drying and firing conditions, eliminating the need for a pulverization process and saving energy. It has the advantages of low consumption and prevention of contamination with impurities during the grinding process, and its industrial value is great.
以下に実施例を挙げて、更に本発明を具体的に
説明する。 EXAMPLES The present invention will be explained in more detail with reference to Examples below.
実施例 １
水酸化アルミニウム〔Al（OH）3、平均粒径3.3μ
ｍ、Na2O0.39重量％含有〕100部とクエン酸１水
和物〔C3H4（OH）（COOH）3・H2Ｏ〕６部に水
1000部を加えて懸濁液を得た。Example 1 Aluminum hydroxide [Al(OH) 3 , average particle size 3.3μ
m, containing 0.39% by weight of Na 2 O] , 100 parts of citric acid monohydrate [C 3 H 4 (OH) (COOH) 3・H 2 O], and 6 parts of water.
1000 parts were added to obtain a suspension.
この懸濁液をオートクレープ中で220℃、24
Kg／cm2Ｇの条件下に６時間攪拌反応させてベーマ
イト懸濁液を得た後、水洗ろ過し1300℃で１時間
焼成を行なつた。このものはNa2Ｏ量が0.01重量
％以下で、平均粒径が0.66μｍのα−Al2O3の粉体
であつた。 This suspension was heated in an autoclave at 220℃ for 24 hours.
The suspension was reacted with stirring for 6 hours under the condition of Kg/cm 2 G to obtain a boehmite suspension, which was then washed with water, filtered, and calcined at 1300° C. for 1 hour. This powder was α-Al 2 O 3 with a Na 2 O content of 0.01% by weight or less and an average particle size of 0.66 μm.
その電子顕微鏡写真を第１図に示した。 The electron micrograph is shown in FIG.
この粉体を1ton／cm2で嵩密度1.57ｇ／cm3に加圧
成形した後、1550℃で２時間焼成したところ、嵩
密度3.83ｇ／cm3の成形体が得られた。即ち、Al2
O3の理論密度3.99ｇ／cm3の96.0％まで焼結が進行
した緻密な成形体が得られた。 This powder was pressure-molded at 1 ton/cm 2 to a bulk density of 1.57 g/cm 3 and then calcined at 1550° C. for 2 hours to obtain a molded body with a bulk density of 3.83 g/cm 3 . That is, Al 2
A dense molded body was obtained in which sintering progressed to 96.0% of the theoretical density of O 3 of 3.99 g/cm 3 .
比較例 １
実施例１のクエン酸１水和物を添加しない以外
は全く同じ処理をして平均粒径1.9μｍのα−Al2
O3の粉体を得た。この粉体を1ton／cm2で嵩密度
1.50ｇ／cm3に加圧成形した後、1550℃で２時間焼
結したところ、嵩密度2.99ｇ／cm3の成形体が得ら
れた。この成形体はAl2O3の理論密度の74.9％ま
でしか焼結は進行していなかつた。Comparative Example 1 α-Al 2 with an average particle size of 1.9 μm was prepared using exactly the same treatment as in Example 1 except that citric acid monohydrate was not added.
O 3 powder was obtained. This powder has a bulk density of 1 ton/cm 2
After pressure molding to 1.50 g/cm 3 and sintering at 1550° C. for 2 hours, a molded product with a bulk density of 2.99 g/cm 3 was obtained. In this compact, sintering had progressed to only 74.9% of the theoretical density of Al 2 O 3 .
比較例 ２
実施例１のクエン酸１水和物の代りにクエン酸
ナトリウムを、クエン酸１水和物６部相当添加
し、他は同一条件で処理したところ、平均粒径
1.6μｍのα−Al2O3の粉体を得た。この粉体を
1ton／cm2で嵩密度1.56ｇ／cm3に加圧成形した後、
1550℃で２時間焼成した。得られた成形体の嵩密
度は3.01ｇ／cm3（理論密度の75.4％）であつた。Comparative Example 2 When sodium citrate was added in place of citric acid monohydrate in Example 1, equivalent to 6 parts of citric acid monohydrate, and the other conditions were the same, the average particle size was
A 1.6 μm α-Al 2 O 3 powder was obtained. This powder
After pressure molding to a bulk density of 1.56 g/cm 3 at 1 ton/cm 2 ,
It was baked at 1550°C for 2 hours. The bulk density of the obtained molded product was 3.01 g/cm 3 (75.4% of the theoretical density).
実施例 ２
実施例１において、クエン酸１水和物の代りに
コハク酸〔（CH2）2（COOH）2〕を６部添加し、
同様にしてNa2Ｏ量が0.01重量％以下で、平均粒
径が0.74μｍのα−Al2O3の粉体を得た。この粉体
を1ton／cm2で嵩密度1.32ｇ／cm3に加圧成形した
後、1550℃で２時間焼成したところ嵩密度3.23
ｇ／cm3（理論密度の81.0％）の成形体が得られ
た。Example 2 In Example 1, 6 parts of succinic acid [(CH 2 ) 2 (COOH) 2 ] was added instead of citric acid monohydrate,
Similarly, α-Al 2 O 3 powder with an amount of Na 2 O of 0.01% by weight or less and an average particle size of 0.74 μm was obtained. This powder was pressure-molded at 1 ton/cm 2 to a bulk density of 1.32 g/cm 3 and then baked at 1550°C for 2 hours, resulting in a bulk density of 3.23.
A molded body having a density of 81.0% of the theoretical density was obtained.
比較例 ３
実施例１において、クエン酸１水和物の代りに
パルミチン酸〔CH3（CH2）14COOH〕を６部添加
し、同様にして平均粒径2.3μｍのα−Al2O3の粉
体を得た。この粉体を1ton／cm2で嵩密度1.41ｇ／
cm3に加圧成形した後、1550℃で２時間焼成した。
得られた成形体の嵩密度は2.33ｇ／cm3（理論密度
の58.4％）であつた。Comparative Example 3 In Example 1, 6 parts of palmitic acid [CH 3 (CH 2 ) 14 COOH] was added instead of citric acid monohydrate, and α-Al 2 O 3 with an average particle size of 2.3 μm was prepared in the same manner. of powder was obtained. This powder has a bulk density of 1.41 g/ cm2 at 1 ton/cm2.
After pressure molding to a size of cm 3 , it was fired at 1550°C for 2 hours.
The bulk density of the obtained molded article was 2.33 g/cm 3 (58.4% of the theoretical density).
実施例 ３
実施例１において、クエン酸１水和物６部の代
りに、クエン酸１水和物10部を添加し、他は全く
同一処理をしたところ、平均粒径0.52μｍのα−
Al2O3の粉体が得られた。Example 3 In Example 1, 10 parts of citric acid monohydrate was added instead of 6 parts of citric acid monohydrate, and the other treatment was the same. As a result, α-
A powder of Al 2 O 3 was obtained.
この粉体を1ton／cm2で嵩密度1.53ｇ／cm3に加圧
成形した後、真空中で1700℃で２時間焼成した。
得られた成形体の嵩密度は3.91ｇ／cm3（理論密度
の98.0％）であつた。 This powder was pressure-molded at 1 ton/cm 2 to a bulk density of 1.53 g/cm 3 and then baked at 1700° C. for 2 hours in a vacuum.
The bulk density of the obtained molded product was 3.91 g/cm 3 (98.0% of the theoretical density).
第１図は実施例１で得られたα−Al2O3粉体の
走査型電子顕微鏡写真を示す。
FIG. 1 shows a scanning electron micrograph of the α-Al 2 O 3 powder obtained in Example 1.
Claims (1)
以上のカルボキシル基を有する水溶性カルボン酸
を加熱加圧下処理し、ベーマイトを得た後、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。1. A method for producing easily sinterable alumina, which comprises treating aluminum hydroxide dispersed in water and a water-soluble carboxylic acid having two or more carboxyl groups under heat and pressure to obtain boehmite, followed by firing. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57190073A JPS5978926A (en) | 1982-10-29 | 1982-10-29 | Manufacture of easily sinterable alumina |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57190073A JPS5978926A (en) | 1982-10-29 | 1982-10-29 | Manufacture of easily sinterable alumina |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1055763A Division JPH01275421A (en) | 1989-03-08 | 1989-03-08 | Production of boehmite |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5978926A JPS5978926A (en) | 1984-05-08 |
| JPH0362648B2 true JPH0362648B2 (en) | 1991-09-26 |
Family
ID=16251905
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57190073A Granted JPS5978926A (en) | 1982-10-29 | 1982-10-29 | Manufacture of easily sinterable alumina |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5978926A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02239113A (en) * | 1989-03-14 | 1990-09-21 | Mitsubishi Kasei Corp | Production of boehmite |
| JPH04130050A (en) * | 1990-09-18 | 1992-05-01 | Nippon Light Metal Co Ltd | Refractory material and its production |
| JP2681569B2 (en) * | 1992-01-17 | 1997-11-26 | 株式会社ユニシアジェックス | Intake air flow rate detection device for internal combustion engine |
| GB9513116D0 (en) * | 1995-06-28 | 1995-08-30 | Sandoz Ltd | Improvements in or relating to organic compounds |
| JP4614354B2 (en) * | 2003-03-10 | 2011-01-19 | 河合石灰工業株式会社 | Heat resistant aluminum hydroxide and method for producing the same |
| JP5217258B2 (en) * | 2007-06-07 | 2013-06-19 | 日本軽金属株式会社 | Sinterable α-alumina and method for producing the same |
| JP5324112B2 (en) * | 2008-03-19 | 2013-10-23 | 関東電化工業株式会社 | Boehmite fine particles and method for producing the same |
| JP5848053B2 (en) * | 2011-07-22 | 2016-01-27 | 株式会社日本触媒 | Method for producing boehmite nanorods, method for producing alumina nanorods, and method for producing CuAlO2 film |
| JP2013212684A (en) * | 2012-03-05 | 2013-10-17 | Aica Kogyo Co Ltd | Scratch resistance decorative sheet |
-
1982
- 1982-10-29 JP JP57190073A patent/JPS5978926A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5978926A (en) | 1984-05-08 |
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