JPH0466806B2 - - Google Patents
Info
- Publication number
- JPH0466806B2 JPH0466806B2 JP25357087A JP25357087A JPH0466806B2 JP H0466806 B2 JPH0466806 B2 JP H0466806B2 JP 25357087 A JP25357087 A JP 25357087A JP 25357087 A JP25357087 A JP 25357087A JP H0466806 B2 JPH0466806 B2 JP H0466806B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- boehmite
- alumina
- aln
- particle size
- 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
Links
- 239000000843 powder Substances 0.000 claims description 67
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 35
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 34
- 229910001593 boehmite Inorganic materials 0.000 claims description 34
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 claims description 34
- 229910052799 carbon Inorganic materials 0.000 claims description 32
- 239000000203 mixture Substances 0.000 claims description 19
- 239000000463 material Substances 0.000 claims description 14
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 238000010304 firing Methods 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 230000001590 oxidative effect Effects 0.000 claims description 6
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 239000012298 atmosphere Substances 0.000 claims description 4
- 239000002245 particle Substances 0.000 description 29
- 238000000034 method Methods 0.000 description 23
- 238000009826 distribution Methods 0.000 description 10
- 230000007704 transition Effects 0.000 description 9
- 239000006185 dispersion Substances 0.000 description 7
- 238000005121 nitriding Methods 0.000 description 7
- 230000002159 abnormal effect Effects 0.000 description 5
- 230000002829 reductive effect Effects 0.000 description 5
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 4
- 230000006911 nucleation Effects 0.000 description 4
- 238000010899 nucleation Methods 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000007858 starting material Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000005261 decarburization Methods 0.000 description 3
- 239000010419 fine particle Substances 0.000 description 3
- 239000003513 alkali Substances 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000004898 kneading Methods 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910002706 AlOOH Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- -1 aluminum alkoxide Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 239000008394 flocculating agent Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 239000003779 heat-resistant material Substances 0.000 description 1
- 239000008241 heterogeneous mixture Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Landscapes
- Ceramic Products (AREA)
Description
〔産業上の利用分野〕
本発明は、高純度、微細で易焼結性の窒化アル
ミニウム粉末の製造方法に関するもので、さらに
詳しくは窒化アルミニウム粉末の粒径の制御が可
能で粒度分布を狭くすることができると共に、再
現性がよく、窒化アルミニウム粉末中に残存する
炭素も少なくし得る方法に関するものである。
〔従来の技術〕
窒化アルミニウム（以下AlNと記す）は、そ
の優れた機械的特性、化学的耐用性の故に耐熱材
料として用いられるだけでなく、その高熱伝導
性、高電気絶縁性、低誘電率等の故に半導体関係
の放熱材料としても期待されている。AlNは一
部薄膜の形態で利用される場合もあるが、多くの
場合焼結体で用いられている。
このようなAlN焼結体の焼結性および特性は、
出発原料であるAlN粉末の特性および焼結助剤
に強く影響されることが知られている。すなわ
ち、AlN粉末としては、高純度で、粒径が均一
かつ微細であり、適当な焼結助剤をAlN粉末中
に均一に分散し得ることが望ましい。
AlN粉末は、従来、金属アルミニウムの直接
窒化法またはアルミナの還元窒化法で製造されて
いる。還元窒化法では微細で均一な粒径の高純度
アルミナを出発原料とすることにより直接窒化法
より若干優れたAlN粉末が得られやすいが、所
望の粉末とは言い難い。
上記方法を改良し、高純度で、微細、均一粒径
のAlN粉末を得る方法として、アルミニウムア
ルコキシドと炭素との分散液に水を加え、アルコ
キシドの加水分解を行わせ水酸化アルミニウムと
炭素との混合物を得る方法、および水溶性アルミ
ニウム塩と炭素とを含む水溶液にアルカリを加
え、中和沈殿法により水酸化アルミニウムと炭素
との混合物を得る方法が提案されている（特開昭
61−6105、特公昭61−26485）。
これらの方法によつて得た混合物は、前記した
アルミナと炭素との混合物に比べ均一に混合され
ているため、これを窒素を含む非酸化性雰囲気中
で焼成することにより、従来より均一で、微細な
AlN粉を得ることができるようになつた。しか
し、この改良法においても加水分解または中和沈
殿のために水またはアルカリを滴下すると、局所
的に沈殿が生成し、直ちに凝集してしまう。この
ため、炭素微粉を含まない水酸化アルミニウムの
1μm以上の凝集塊が多数生成し、得られる水酸化
アルミニウムと炭素との混合物は均一性が不十分
なものである。このような不均一な混合物を窒素
を含む非酸化性雰囲気中で焼成して得られる
AlN粉末の粒径は不揃いなものになり易く、焼
成後もアルミナが窒化されずに残つたり１〜5μm
の粗粒のAlNとなりがちであつた。
以上の問題点を解決するために、本発明者らは
特願昭61−283206（特開昭63−139008号公報参照）
において、分散性、分散液の安定性に優れるベー
マイト（AlOOH）または凝ベーマイト粉を用
い、炭素源物質との均一な分散液を作製し、この
均一分散状態を保つたまま固化させ、これを乾
燥、焼成することによつて微細な粒度分布範囲の
狭いAlN粉末を得る方法を開示した。しかし、
この方法においても、固体炭素を炭素源物質とし
て用いる場合には、その粒径および分散状態によ
つて、得られるAlN粉末の粒径分布が変動し易
く、例えば粒径が1μmを超える大きさとなつた
り、また分散が不十分な場合には1μm以上の凝結
したAlN粉末が多数認められたり、極端な場合
には窒化が不十分でアルミナが残存する場合もあ
つた。
特願昭61−283206に開示された方法の問題点を
解決するために、本発明者らは特願昭62−036633
（特開昭63−206306号公報参照）において、水溶
性の有機炭素源物質と固体炭素粉を所定の割合で
配合した炭素源物質を用いることにより、特願昭
61−283206に開示された方法によつて得られる
AlN粉末よりさらに微細で粒度分布範囲の狭い
良質のAlN粉末を安定に得る方法を開示した。
しかし、この方法においても、炭素源物質として
水溶性有機炭素源物質を固体炭素粉と併用するこ
とにより、さらに良質のAlN粉末を得ることが
できたが、下記の問題点が残されていた。
すなわち、ベーマイト粉は昇温時に一旦α−ア
ルミナ（α−Al2O3）相に転移し、この転移の際
に粒径の異常成長が起こる。このため、例え超微
粉のベーマイトを出発原料として用いても粗大な
α−アルミナとなつてしまう場合があり、還元窒
化後のAlN粉末にも1μm以上の粗大なものが認め
られたり、AlN粉末の粒度分布が変動する場合
も見られ、微細で粒度分布範囲の狭い良質の
AlN粉末を再現性よく製造する際の問題点の１
つとして残されていた。さらに上記の相転移の際
に粒成長が極めて急速に起こるために、共存する
炭素源物質がアルミナ粒内に多数トラツプされ、
還元窒化反応後も多量に残留することが分つた。
この粒内残留炭素は還元窒化反応後の酸化脱炭工
程でも酸化除去するのが難しく、最終的に得られ
るAlN粉末中の残留炭素が比較的高い場合が多
いという問題がある。
〔発明が解決しようとする問題点〕
本発明は高純度で微細な、焼結性にすぐれた
AlN粉末の製造法に関する上記開示をさらに発
展させ、粒度分布範囲が狭く、微細で、残留炭素
の少ないAlN粉末を再現性よく製造する方法を
提供しようとするものである。
〔問題点を解決するための手段〕
本発明者らは上記従来技術の問題点を解決する
ため種々研究の結果、ベーマイト粉の昇温時にお
けるα−アルミナ相への転移に際する粒径の異常
成長は、ベーマイトゾルと炭素源物質との混合物
にα−アルミナ粉末を含有させることにより、防
止し得ることを発見し本発明に到達したもので、
下記の技術手段からなるものである。
すなわち、本発明は、特願昭61−283206および
特願昭62−036633に開示された技術を発展させた
もので、これ等に開示された方法において、ベー
マイトゾルと炭素源物質との混合物に、ベーマイ
ト粉に対して0.01〜50重量％のα−アルミナ粉末
を含有させることを特徴とするものである。
ベーマイトゾルと炭素源物質との混合物にα−
アルミナ粉末を含有させる方法としては、粉末の
まま、あるいは水に加えてアルミナスラリーとし
てベーマイトゾルまたは前記混合物に添加しても
良いが、PHを1.2〜4.5に調整したアルミナスラリ
ーとして添加すると、α−アルミナ粉末の分散が
良好となり好ましい。
本発明に用いられるベーマイト粉としては凝ベ
ーマイト粉も使用できる。凝ベーマイトは、ベー
マイト結晶と同位置にＸ線回折ピークが現れるが
ベーマイト結晶に比べてピーク幅が広く、結晶性
の不十分なベーマイトであるが、水中の分散性は
ベーマイト結晶と大差はない。
水にベーマイト粉を加えたベーマイトスラリー
のPHを1.2〜4.5に調整しベーマイトゾルを作成す
るには、例えば適量の硝酸が用いられる。
α−アルミナ粉末を含有しているベーマイトゾ
ルと炭素源物質との混合物を乾燥するには、この
混合物を、
(1) 長時間混練する、
(2) 混練しながら加熱等により水を蒸発させる、
(3) 酸、アルカリ、種々なイオン、高分子凝集剤
を添加する、
等の方法によりゲル化し、ベーマイト粉と炭素源
物質とα−アルミナ粉末との均一混合状態をその
まま保持して固化し、適宜な方法で乾燥する。
このようにして得られた乾燥物を、窒素を含む
非酸化性雰囲気中で1350〜1800℃で焼成すること
によりAlN粉末が得られる。
〔作用〕
ベーマイト粉は焼成における昇温時に、一旦α
−アルミナ相に転移し、この転移の際に粒子の異
常成長が起こるが、微粉のα−アルミナ粉末を添
加しておくと、添加したα−アルミナ粉末はベー
マイトからα−アルミナへの転移に際し核生成サ
イトとして作用し、粒子の異常成長を防ぐことが
できる。
アルミナにはα−アルミナの他に、γ−アルミ
ナ等の準安定相があるが、準安定相のアルミナに
は上記の核生成サイトとしての作用が認められな
いばかりでなく、昇温時にα−アルミナ相に転移
する時にベーマイト粉と同様に粒子が異常成長
し、その結果AlNの粗粒を生じ、本発明の効果
を挙げることはできない。
ベーマイトゾルと炭素源物質との混合物に含有
させるα−アルミナ粉末の量は、ベーマイト粉に
対し0.01〜50重量％とする。0.01重量％未満では
核生成サイト数が不十分で、前記転移に伴う急激
な粒成長を抑制できず、50重量％を越えると、分
散性が良く、かつ微細な粒径を有するベーマイト
を用いる利点が殆どなく、α−アルミナ粉末を出
発原料とする従来の技術と実質的に同じものにな
る。
本発明に用いられるα−アルミナ粉末の粒度は
特に限定されるものではないが、ベーマイトから
α−アルミナへの転移に際し、核生成サイトとな
るものであるので、多数の核生成サイトを持ち込
んで微粉のAlN粉末を生じさせるため、また、
添加したα−アルミナ粉末も炭素源物質と窒素と
によつて還元窒化されてAlN粉末を生じるので
なるべく微粉であることが好ましく、製造しよう
とするAlN粉末より粒径の小さいものが望まし
く、α−アルミニウム粉末の粒度を選択すること
により、任意の粒度を有し、粒度分布の狭い
AlN粉末を製造することができる。
また、本発明においては、ベーマイトからα−
アルミナへの相転移において粒の異常成長を生じ
ないので、炭素源物質がα−アルミナ粒内に多数
トラツプされることがなくなり、酸化脱炭工程に
おける炭素の酸化除去が容易となり、AlN粉末
製品中の残留炭素を減少させることができる。
〔実施例〕
第１表に示した〜の配合でAlN粉末製造
用の混合物を作製し、窒素雰囲気中で1600℃、５
時間焼成したのち、650℃で３時間脱炭処理し、
AlN粉末を得た。第１表中、、、、
は本発明の製造条件に適合する実施例であり、
、、、は比較例である。これらの混合物
は全て以下の手順で作成した。
これ等の混合物は、全て以下の手順で作製し
た。
PH＝3.0で水中に分散させた濃度20重量％のベ
ーマイトゾルと、固体炭素数に分散剤と水を加え
ポツトミルで10時間混練して得た炭素濃度15重量
％の分散体とを予め作成した。
両者を炭素／ベーマイト重量比＝１となるよう
に混合したのち、PH＝3.0で水中に分散させた濃
度10重量％のα−アルミナ粉末（平均粒径
0.3μm）を所定量添加混合し、加熱によつて水を
除去し、ゲル化させた後乾燥した。
試験は各条件でそれぞれ５回行つた。
[Industrial Application Field] The present invention relates to a method for producing aluminum nitride powder that is highly pure, fine, and easily sinterable. The present invention relates to a method that can reduce the amount of carbon remaining in aluminum nitride powder with good reproducibility. [Prior Art] Aluminum nitride (hereinafter referred to as AlN) is not only used as a heat-resistant material because of its excellent mechanical properties and chemical durability, but also because of its high thermal conductivity, high electrical insulation, and low dielectric constant. For these reasons, it is also expected to be used as a heat dissipation material for semiconductors. Although AlN is sometimes used in the form of a thin film, it is often used in the form of a sintered body. The sinterability and properties of such AlN sintered bodies are
It is known that this is strongly influenced by the properties of the starting material AlN powder and the sintering aid. That is, it is desirable that the AlN powder has high purity, uniform and fine particle size, and that an appropriate sintering aid can be uniformly dispersed in the AlN powder. AlN powder has conventionally been produced by direct nitriding of metal aluminum or reductive nitriding of alumina. In the reductive nitriding method, AlN powder that is slightly better than the direct nitriding method is easily obtained by using high-purity alumina with fine and uniform particle size as a starting material, but it is difficult to say that it is the desired powder. As a method to improve the above method and obtain AlN powder with high purity, fine, and uniform particle size, water is added to a dispersion of aluminum alkoxide and carbon, and the alkoxide is hydrolyzed to form a mixture of aluminum hydroxide and carbon. A method for obtaining a mixture and a method for obtaining a mixture of aluminum hydroxide and carbon by adding an alkali to an aqueous solution containing a water-soluble aluminum salt and carbon and using a neutralization precipitation method have been proposed (Japanese Patent Application Laid-Open No.
61-6105, Special Publication Showa 61-26485). The mixtures obtained by these methods are more uniformly mixed than the above-mentioned mixtures of alumina and carbon, so by firing them in a non-oxidizing atmosphere containing nitrogen, they are more uniform than before. minute
It is now possible to obtain AlN powder. However, even in this improved method, when water or alkali is dropped for hydrolysis or neutralization precipitation, precipitates are locally generated and immediately coagulate. For this reason, aluminum hydroxide that does not contain carbon fines
Many aggregates of 1 μm or more are formed, and the resulting mixture of aluminum hydroxide and carbon has insufficient uniformity. obtained by firing such a heterogeneous mixture in a non-oxidizing atmosphere containing nitrogen.
The particle size of AlN powder tends to be irregular, and the alumina may remain unnitrided even after firing, or 1 to 5 μm.
The result was a tendency to form coarse-grained AlN. In order to solve the above-mentioned problems, the inventors of the present invention have proposed the following: Japanese Patent Application No. 61-283206
In this process, a uniform dispersion with a carbon source substance is prepared using boehmite (AlOOH) or coagulated boehmite powder, which has excellent dispersibility and stability of the dispersion, solidified while maintaining this uniform dispersion state, and then dried. disclosed a method for obtaining fine AlN powder with a narrow particle size distribution range by calcination. but,
Even in this method, when solid carbon is used as a carbon source material, the particle size distribution of the resulting AlN powder tends to vary depending on its particle size and dispersion state. For example, if the particle size exceeds 1 μm, In cases where the dispersion was insufficient, many coagulated AlN powders of 1 μm or more were observed, and in extreme cases, nitriding was insufficient and alumina remained. In order to solve the problems of the method disclosed in Japanese Patent Application No. 62-036633, the present inventors
(Refer to Japanese Unexamined Patent Publication No. 63-206306), by using a carbon source material containing a water-soluble organic carbon source material and solid carbon powder in a predetermined ratio,
Obtained by the method disclosed in 61-283206
We have disclosed a method for stably obtaining high-quality AlN powder, which is finer than AlN powder and has a narrow particle size distribution range.
However, even in this method, even better quality AlN powder could be obtained by using a water-soluble organic carbon source material in combination with solid carbon powder as a carbon source material, but the following problems remained. That is, boehmite powder once transforms into an α-alumina (α-Al 2 O 3 ) phase when the temperature rises, and abnormal growth of particle size occurs during this transition. For this reason, even if ultrafine boehmite powder is used as a starting material, it may turn into coarse α-alumina, and coarse particles of 1 μm or more may be observed in the AlN powder after reductive nitriding. There are also cases where the particle size distribution fluctuates, and fine quality particles with a narrow particle size distribution range are
Problem 1 when producing AlN powder with good reproducibility
It was left as one. Furthermore, since grain growth occurs extremely rapidly during the above phase transition, many coexisting carbon source substances are trapped within the alumina grains.
It was found that a large amount remained even after the reduction-nitridation reaction.
This intragranular residual carbon is difficult to oxidize and remove even in the oxidative decarburization step after the reductive nitriding reaction, and there is a problem in that the residual carbon in the finally obtained AlN powder is often relatively high. [Problems to be solved by the invention] The present invention provides highly pure and fine particles with excellent sinterability.
The present invention further develops the above-mentioned disclosure regarding the method for producing AlN powder, and attempts to provide a method for producing AlN powder that has a narrow particle size distribution range, is fine, and has little residual carbon with good reproducibility. [Means for Solving the Problems] In order to solve the above-mentioned problems of the prior art, the present inventors have conducted various studies and found that the particle size of boehmite powder during its transition to the α-alumina phase when heated is increased. The present invention was achieved by discovering that abnormal growth can be prevented by incorporating α-alumina powder into the mixture of boehmite sol and carbon source material.
It consists of the following technical means. That is, the present invention is a development of the technology disclosed in Japanese Patent Application No. 61-283206 and Japanese Patent Application No. 62-036633. It is characterized by containing α-alumina powder in an amount of 0.01 to 50% by weight based on boehmite powder. α- in the mixture of boehmite sol and carbon source material
The alumina powder may be added to the boehmite sol or the above mixture either as a powder or as an alumina slurry in addition to water. This is preferable because the alumina powder can be well dispersed. As the boehmite powder used in the present invention, coagulated boehmite powder can also be used. Precipitated boehmite has an X-ray diffraction peak that appears at the same position as boehmite crystals, but the peak width is wider than boehmite crystals, and boehmite has insufficient crystallinity, but its dispersibility in water is not much different from boehmite crystals. For example, an appropriate amount of nitric acid is used to create a boehmite sol by adjusting the pH of a boehmite slurry made by adding boehmite powder to water to 1.2 to 4.5. In order to dry a mixture of boehmite sol containing α-alumina powder and a carbon source material, the mixture is (1) kneaded for a long time, (2) water is evaporated by heating or the like while kneading. (3) Gelling by adding acids, alkalis, various ions, polymer flocculants, etc., and solidifying while maintaining the homogeneous mixed state of boehmite powder, carbon source material, and α-alumina powder, Dry using an appropriate method. AlN powder is obtained by firing the dried product thus obtained at 1350 to 1800°C in a non-oxidizing atmosphere containing nitrogen. [Function] When the temperature is raised during firing, boehmite powder once loses its α
-Transition to the alumina phase, and abnormal growth of particles occurs during this transition. However, if fine α-alumina powder is added, the added α-alumina powder will form nuclei during the transition from boehmite to α-alumina. It can act as a generation site and prevent abnormal growth of particles. In addition to α-alumina, alumina has metastable phases such as γ-alumina, but metastable alumina not only does not function as the above-mentioned nucleation site, but also has α-alumina when heated. During the transition to the alumina phase, the particles grow abnormally like boehmite powder, resulting in coarse AlN particles, making it impossible to achieve the effects of the present invention. The amount of α-alumina powder contained in the mixture of boehmite sol and carbon source material is 0.01 to 50% by weight based on the boehmite powder. If it is less than 0.01% by weight, the number of nucleation sites is insufficient and the rapid grain growth accompanying the transition cannot be suppressed, and if it exceeds 50% by weight, there are advantages of using boehmite which has good dispersibility and a fine particle size. This method is substantially the same as the conventional technology using α-alumina powder as a starting material. The particle size of the α-alumina powder used in the present invention is not particularly limited, but since it serves as a nucleation site during the transition from boehmite to α-alumina, a large number of nucleation sites are brought in to form a fine powder. Also, to give rise to AlN powder,
The added α-alumina powder is also reduced and nitrided by the carbon source material and nitrogen to produce AlN powder, so it is preferably as fine a powder as possible, and it is desirable that the particle size is smaller than the AlN powder to be manufactured. By selecting the particle size of aluminum powder, it can have any particle size and narrow particle size distribution.
AlN powder can be produced. In addition, in the present invention, α-
Since abnormal grain growth does not occur during the phase transition to alumina, a large number of carbon source substances are not trapped within the α-alumina grains, making it easy to oxidize and remove carbon in the oxidative decarburization process, and improve the quality of AlN powder products. can reduce residual carbon. [Example] A mixture for producing AlN powder was prepared using the formulations shown in Table 1, and heated at 1600°C for 50 minutes in a nitrogen atmosphere.
After firing for an hour, decarburization treatment was performed at 650℃ for 3 hours.
AlN powder was obtained. In Table 1...
is an example that conforms to the manufacturing conditions of the present invention,
, , are comparative examples. All of these mixtures were created using the following procedure. All of these mixtures were prepared using the following procedure. A boehmite sol with a concentration of 20% by weight dispersed in water at pH = 3.0 and a dispersion with a carbon concentration of 15% by weight obtained by adding a dispersant and water to the solid carbon number and kneading in a pot mill for 10 hours were prepared in advance. . After mixing the two so that the carbon/boehmite weight ratio = 1, α-alumina powder (average particle size
A predetermined amount of 0.3 μm) was added and mixed, water was removed by heating, the mixture was gelatinized, and then dried. The test was conducted five times under each condition.
【表】
上記〜の９種類のAlN粉末の粒度分布の
平均値を第１図に示す。第１図および走査型電子
顕微鏡による観察から以下のことを確認できた。
比較例、、、では粒径分布が広く、平
均粒径も大きいだけでなく、5μm以上まで異常成
長した粒が散見された。
実施例、、、、では比較例、、
、に比べ、粒径が小さく、粒度分布が狭く、
異常成長した粒は認められず、かつ５回の試験の
間の粒径のばらつきも小さい。
〔発明の効果〕
本発明によつて、微細で、均一粒径のAlN粉
末を極めて再現性よく製造することが可能になつ
た。
このAlN粉末を用いることにより、高純度で、
高熱伝導性、高強度のAlN焼結体を製造するこ
とが容易となり、高温構造材料、IC（集積回路）
基板等への利用に貢献するところが大である。[Table] Figure 1 shows the average particle size distribution of the nine types of AlN powders listed above. The following things were confirmed from FIG. 1 and observation using a scanning electron microscope. In Comparative Examples, . Example, Comparative example,
, the particle size is smaller and the particle size distribution is narrower than that of
No abnormally grown grains were observed, and the variation in grain size among the five tests was small. [Effects of the Invention] According to the present invention, it has become possible to produce fine AlN powder with a uniform particle size with extremely high reproducibility. By using this AlN powder, high purity
It is now easy to produce high thermal conductivity and high strength AlN sintered bodies, which can be used as high-temperature structural materials and IC (integrated circuits).
This greatly contributes to its use in substrates, etc.
第１図は種々の方法で作製したAlN粉末の粒
度分布を示すグラフである。
FIG. 1 is a graph showing the particle size distribution of AlN powder produced by various methods.
Claims (1)
整して該ベーマイト粉を分散させたベーマイトゾ
ルを作製し、該ベーマイトゾルと炭素源物質とを
混合し、該混合物を乾燥した後、窒素を含む非酸
化性雰囲気中で焼成する窒化アルミニウム粉末の
製造方法において、該ベーマイトゾルと該炭素源
物質との混合物に、該ベーマイト粉に対して0.01
〜50重量％のα−アルミナ粉末を含有させること
を特徴とする窒化アルミニウム粉末の製造方法。1 Add boehmite powder to water, adjust the pH to 1.2 to 4.5, and prepare a boehmite sol in which the boehmite powder is dispersed, mix the boehmite sol and a carbon source material, dry the mixture, and then add nitrogen In the method for producing aluminum nitride powder, which involves firing in a non-oxidizing atmosphere containing
A method for producing aluminum nitride powder, characterized by containing ~50% by weight of α-alumina powder.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25357087A JPH0196004A (en) | 1987-10-09 | 1987-10-09 | Production of aluminum nitride powder |
| CA000552817A CA1270365A (en) | 1986-11-28 | 1987-11-26 | Method for producing aluminum nitride powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25357087A JPH0196004A (en) | 1987-10-09 | 1987-10-09 | Production of aluminum nitride powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0196004A JPH0196004A (en) | 1989-04-14 |
| JPH0466806B2 true JPH0466806B2 (en) | 1992-10-26 |
Family
ID=17253209
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25357087A Granted JPH0196004A (en) | 1986-11-28 | 1987-10-09 | Production of aluminum nitride powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0196004A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7626801B2 (en) * | 2023-07-13 | 2025-02-04 | 株式会社Maruwa | Aluminum nitride powder, its modification method, and polymer molded body |
-
1987
- 1987-10-09 JP JP25357087A patent/JPH0196004A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0196004A (en) | 1989-04-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4780299A (en) | Method for producing aluminum nitride powder | |
| US4619817A (en) | Hydrothermal method for producing stabilized zirconia | |
| EP3502052A1 (en) | Method for preparing spherical aluminum nitride powder | |
| KR20130098351A (en) | Method for manufacturing spherical aluminum nitride powder | |
| JP2922096B2 (en) | Method for producing hexagonal boron nitride powder | |
| JPH02503790A (en) | sinterable nitride | |
| US5204300A (en) | Methods of seeding sintered objects | |
| JP3636370B2 (en) | Aluminum nitride powder and method for producing the same | |
| CN113045319A (en) | Sintering aid modified nano ceramic powder and preparation method thereof | |
| CN117545712B (en) | Hexagonal boron nitride powder and its manufacturing method, as well as cosmetics and their manufacturing methods | |
| JP7516872B2 (en) | High-purity fine alumina powder | |
| JPH06305726A (en) | Production of powdery oxide of rare earth element | |
| JPH0466806B2 (en) | ||
| JPH0323206A (en) | Aluminum nitride powder and its production | |
| CA1270365A (en) | Method for producing aluminum nitride powder | |
| JPH0535682B2 (en) | ||
| JP7761055B2 (en) | High-purity fine alumina powder | |
| JPS63139008A (en) | Production of powdery aluminum nitride | |
| JPH01122964A (en) | Zirconia stabilized with yttrium and its production method | |
| JPH0465003B2 (en) | ||
| KR900000036B1 (en) | Ceramic Sintered Body and Sintering Method of Ceramic Body | |
| JP3340171B2 (en) | Manufacturing method of aluminum nitride sintered body | |
| KR102603948B1 (en) | A SiC Slurry and Manufacturing method of the same | |
| JPS5918106A (en) | Preparation of silicon aluminum oxynitride type powdery raw material | |
| EP0582644B1 (en) | Process for preparing mixed oxides |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |