JPS63265865A - Production of aluminum nitride sintered body - Google Patents

Production of aluminum nitride sintered body

Info

Publication number
JPS63265865A
JPS63265865A JP62099994A JP9999487A JPS63265865A JP S63265865 A JPS63265865 A JP S63265865A JP 62099994 A JP62099994 A JP 62099994A JP 9999487 A JP9999487 A JP 9999487A JP S63265865 A JPS63265865 A JP S63265865A
Authority
JP
Japan
Prior art keywords
aluminum nitride
sintered body
powder
nitrogen
molding
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.)
Pending
Application number
JP62099994A
Other languages
Japanese (ja)
Inventor
Atsushi Ariga
有賀 敦
Yukihiko Miwa
三和 幸彦
Masayasu Yamaguchi
山口 雅靖
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Taiheiyo Cement Corp
Original Assignee
Onoda Cement Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Onoda Cement Co Ltd filed Critical Onoda Cement Co Ltd
Priority to JP62099994A priority Critical patent/JPS63265865A/en
Publication of JPS63265865A publication Critical patent/JPS63265865A/en
Pending legal-status Critical Current

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Abstract

PURPOSE:To obtain an AlN sintered body having good heat conductivity in particular by covering a molding of a mixture composed of AlN powder and CaCN2 with a powder mixture consisting of AlN powder added with a Ca-contg. compd., and calcining the molding under an atmospheric pressure or pressurization in a nonoxidizing atmosphere. CONSTITUTION:The CaCN2 as the sintering assistant is added and mixed to and with the AlN powder at preferably 0.01-7wt.% ratio. Mixing is preferably executed while a nonaq. solvent such as acetone is added to the mixture and further gaseous N2 replacement is executed. The resultant powder mixture is then molded by a pressurizing press at a room temp. to a prescribed shape. Said molding is coated with the powder mixture consisting of the AlN added with the Ca-contg. compd. (e.g.: CaO) and is then subjected to atmospheric pressure calcination in the nonoxidizing atmosphere. The molding is otherwise calcined in N2 of over the atmospheric pressure and 50kg/cm<2> nitrogen pressure or the gaseous mixture composed of N2 and inert gas. The above-mentioned calcination temp. is 1,500-2,200 deg.C, more preferably 1,600-2,100 deg.C. The desired AlN sintered body is obtd. by the above-mentioned calcination treatment.

Description

【発明の詳細な説明】 [産業上の利用分野コ 本発明は窒化アルミニウム焼結体、特に熱伝導性の良好
な窒化アルミニウム焼結体の製造方法に関する。
DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing an aluminum nitride sintered body, particularly an aluminum nitride sintered body having good thermal conductivity.

[従来の技術] 近年、電子−器の高速・高性能化、小型・軽量化が進む
中で半導体素子の単位面積当たりの発熱量が大幅に増加
し、この発熱のなめに半導体素子の正常な動作が妨げら
れる問題が生じ始めている。
[Prior Art] In recent years, as electronic devices have become faster, more sophisticated, smaller, and lighter, the amount of heat generated per unit area of semiconductor devices has increased significantly, and this heat generation has caused problems in the normal operation of semiconductor devices. Problems are starting to occur that are interfering with operation.

特に、高密度実装置C,LS1.VLSI、マイクロ波
通信及び光通信用のマイクロウェーブ用l・ランジスタ
、レーザーダイオード等では熱伝導性の高い絶縁性基板
材料の要求が強い。
In particular, high-density actual device C, LS1. There is a strong demand for insulating substrate materials with high thermal conductivity for VLSI, microwave communications, microwave transistors for optical communications, laser diodes, and the like.

従来、絶縁性基板材料には一般にアルミナ焼結体が多く
用いられているが、最近の絶縁性基板材料としてはアル
ミナ基板では熱の放散性(熱伝導性)が悪く、熱膨張係
数もシリコンに比べて太き過ぎる。このため、熱放散性
が良好な絶縁性基板材料の開発が要求されている。この
ような絶縁性基板としては ■熱伝導性が良い(熱伝導率が大きい);■電気絶縁性
が大きい; ■熱膨張係数がシリコンに近いこと; ■機械的強度が大きいこと 等の特性が要求される。
Traditionally, alumina sintered bodies have been commonly used as insulating substrate materials, but as for recent insulating substrate materials, alumina substrates have poor heat dissipation (thermal conductivity) and a thermal expansion coefficient that is lower than that of silicon. It's too thick in comparison. Therefore, there is a need to develop an insulating substrate material with good heat dissipation properties. Such insulating substrates have the following characteristics: ■ Good thermal conductivity (high thermal conductivity); ■ High electrical insulation; ■ The coefficient of thermal expansion is close to that of silicon; ■ High mechanical strength. required.

ところで、熱伝導性の高い基板材料として有望視されて
いる窒化アルミニウムは熱膨張係数が約4.3 X 1
0−’/’Cでアルミナ焼結体の約7×10−’/’C
に比べて小さく、シリコンの熱膨張係数的3.5 X 
10−’/’Cに近い、また、機械的強度も曲げ強さで
約50 kg/ mm2と、アルミナ焼結体の約20 
kg/ mm2に比べて高強度であることが知られてい
る。更に、電気抵抗が10′4Ωcm以上と電気絶縁性
も優れた材料である。その他、絶縁耐圧、誘電率等がア
ルミナ焼結体の諸特性と同等もしくはそれ以上であるた
め、その製造方法が鋭意研究開発されている。
By the way, aluminum nitride, which is seen as a promising substrate material with high thermal conductivity, has a coefficient of thermal expansion of approximately 4.3 x 1.
Approximately 7×10-'/'C of alumina sintered body at 0-'/'C
It is smaller compared to the thermal expansion coefficient of silicon, which is 3.5
The bending strength is close to 10-'/'C, and the mechanical strength is approximately 50 kg/mm2, which is approximately 20 kg/mm2 for the alumina sintered body.
It is known to have high strength compared to kg/mm2. Furthermore, it is a material with excellent electrical insulation properties, with an electrical resistance of 10'4 Ωcm or more. In addition, since its dielectric strength, dielectric constant, etc. are equivalent to or higher than the various properties of alumina sintered bodies, methods of manufacturing it are being actively researched and developed.

しかしながら、窒化アルミニウムは難焼結性物質である
ため、単体では常圧焼結した場合に緻密な焼結体とする
ことが困難である。そのために加圧・加熱を伴うホット
プレス法、ガス圧加圧法、HIP法による焼結体の製造
法や各種化合物を焼結助剤として添加した常圧焼結によ
るfft結体0製造法が検討されている。これらの製造
法の中で常圧焼結法は大量生産に向いているので望まし
い焼結体の製造方法である。例えば特開昭54−100
410号公報には酸化カルシウム(Cao )、酸化バ
リウム(B ao )、酸化ストロンチウム(S ro
 )等を焼結助剤として加える窒化アルミニウム焼結体
の製造方法が示されている。しかし、この方法で得られ
る窒化アルミニウムの熱伝導率は50〜60W/iKと
低く、更に高い熱伝導性を有する窒化アルミニウム焼結
体の製造方法が探求されている。
However, since aluminum nitride is a substance that is difficult to sinter, it is difficult to form a dense sintered body when sintering it alone under normal pressure. For this purpose, methods for manufacturing sintered bodies using the hot press method, gas pressure pressurization method, and HIP method that involve pressure and heating, as well as a method for manufacturing fft compacts using pressureless sintering with the addition of various compounds as sintering aids, are being considered. has been done. Among these manufacturing methods, the pressureless sintering method is suitable for mass production and is therefore a preferred method for manufacturing sintered bodies. For example, JP-A-54-100
410, calcium oxide (Cao), barium oxide (Bao), strontium oxide (Sro)
) etc. are added as sintering aids to produce an aluminum nitride sintered body. However, the thermal conductivity of aluminum nitride obtained by this method is as low as 50 to 60 W/iK, and a method for producing an aluminum nitride sintered body having even higher thermal conductivity is being sought.

更に、特開昭60−151280号公報には、添加剤と
してCa、S(Ba等のアセチリド化合物を加える方法
が、また、特開昭60−186478号公報にはCIL
3 N 2、Mg3N2、S r3 N 2、Ba、N
zを焼結補助剤として添加して窒化アルミニウムを焼結
する方法が開示されている。しかし、これらの方法では
焼結助剤として使われる化合物が空気中で非常に不安定
である等の問題点がある0例えば、特開昭60−151
280号公報のカルシウムアセチリドは水と激しく反応
し、アセチレンガスを放出するため、粒度150メツシ
ユ以下の場合空気中に1時間放置すると、全てCa(O
H)2に分解してしまい、取り扱いに注意を要する。ま
た、焼結助剤が焼結体に残り易く、電気絶縁性が若干劣
る傾向がある。
Furthermore, JP-A No. 60-151280 describes a method of adding acetylide compounds such as Ca, S (Ba, etc.) as additives, and JP-A No. 60-186478 describes a method of adding acetylide compounds such as Ca and S (Ba).
3N2, Mg3N2, Sr3N2, Ba, N
A method of sintering aluminum nitride by adding z as a sintering aid is disclosed. However, these methods have problems such as the compound used as a sintering aid being very unstable in air.
Calcium acetylide in Publication No. 280 reacts violently with water and releases acetylene gas, so if the particle size is 150 mesh or less and is left in the air for 1 hour, all Ca(O
H) It decomposes into 2, so care must be taken when handling it. In addition, the sintering aid tends to remain on the sintered body, and the electrical insulation properties tend to be slightly inferior.

また、特開昭60−186478号公報に記載されてい
る窒化カルシウム(平均粒径3μ)に至っては空気に触
れると瞬間にCa(OH)zに分解してしまう、この欠
点は空気または水の存在しない状態で取り扱えば克服で
きそうに思われるが、実際には、基板製造の各工程(粉
砕、混合、成形、脱脂、焼成)中に分解を防止すること
は大きな困難を伴い、特別な工夫をすることによりコス
ト高となる。
Furthermore, calcium nitride (average particle size 3μ) described in JP-A-60-186478 decomposes into Ca(OH)z instantly when it comes into contact with air. Although it seems possible to overcome this problem by handling the product in its non-existent state, in reality, preventing decomposition during each step of substrate manufacturing (pulverization, mixing, molding, degreasing, and baking) is extremely difficult and requires special ingenuity. This increases costs.

前記のポットプレス法やHIP法は複雑形状品や大型成
形品の製造には適しておらず、しかも、かなりコストが
高くなるという欠点を有する。
The pot press method and the HIP method described above are not suitable for producing products with complex shapes or large molded products, and have the disadvantage of being considerably high in cost.

これに対して、常圧焼結法は前述のように量産化が容易
で且つ低コスト化が可能であるが、次に示すような欠点
があった。常圧焼結法で用いられる焼結助剤は特公昭6
1−28629号公報に見られるように、−iに高温で
の蒸気圧が比較的高く、焼結時に粉末成形体の表面付近
の焼結助剤が蒸発・揮散する。そのため、焼結体の表面
付近が緻密化しなかったり、あるいは形状によっては焼
結体が大幅に変形するという欠点があった。特に、添加
物としてアルカリ土類金属を用いたときに、これは顕著
となり、また、焼結体の形状が平板状のように体積当た
りの表面積が大きい程顕著となる。
On the other hand, although the pressureless sintering method allows for easy mass production and cost reduction as described above, it has the following drawbacks. The sintering aid used in the pressureless sintering method is
As seen in Japanese Patent No. 1-28629, -i has a relatively high vapor pressure at high temperatures, and the sintering aid near the surface of the powder compact evaporates and volatilizes during sintering. Therefore, there is a drawback that the vicinity of the surface of the sintered body is not densified or the sintered body is significantly deformed depending on the shape. This is particularly noticeable when an alkaline earth metal is used as an additive, and becomes more noticeable as the sintered body has a larger surface area per volume, such as a flat plate shape.

このため、焼結後の寸法精度が良くなく、表面の焼けて
いない部分を切断や研京などの加工により寸法の調整や
表面平滑性等を調節する必要がある。
For this reason, the dimensional accuracy after sintering is poor, and it is necessary to adjust the dimensions and surface smoothness by cutting or grinding the unsintered portions of the surface.

また、焼結体密度が上がっていない部分も残るので熱伝
導率の良い物が得られにくい。
In addition, since some parts remain where the density of the sintered body has not increased, it is difficult to obtain a product with good thermal conductivity.

そこで本出願人は特願昭61−25794号で窒化アル
ミニウム粉末にカルシウムシアナミドを添加・混合し、
得られた混合物を成形後、非酸化性雰囲気中で焼結する
と、熱伝導性の高い窒化アルミニウム焼結体が得られる
ことを提唱した。
Therefore, the present applicant added and mixed calcium cyanamide to aluminum nitride powder in Japanese Patent Application No. 61-25794.
They proposed that aluminum nitride sintered bodies with high thermal conductivity could be obtained by molding the resulting mixture and sintering it in a non-oxidizing atmosphere.

[発明が解決しようとする問題点] しかし、窒化アルミニウム焼結体中の酸素及び粒界はフ
ォノン散乱の原因となり、熱伝導度を下げる。そこで、
焼結時に上述の酸素をトラップして焼結体の外に除去し
、熱伝導度の向上を図らねばならない、その方法として
、特願昭61−25794号では、窒化アルミニウムに
焼結助剤としてカルシウムシアナミドを添加・混合して
いる。カルシウムシアナミドは焼結時にカルシウム、炭
素、窒素に容易に分解する。
[Problems to be Solved by the Invention] However, oxygen and grain boundaries in the aluminum nitride sintered body cause phonon scattering and lower thermal conductivity. Therefore,
During sintering, the above-mentioned oxygen must be trapped and removed from the sintered body to improve thermal conductivity.As a method for this, Japanese Patent Application No. 61-25794 proposes using aluminum nitride as a sintering aid. Calcium cyanamide is added and mixed. Calcium cyanamide easily decomposes into calcium, carbon, and nitrogen during sintering.

CaCN 2” Ca+ C+ N 2このうち、炭素
が酸素と反応してCoガスまたはCO2ガスとして成形
体の外へ除去され、カルシウムも酸素を奪い、アルミナ
と反応してCa0・2A1203として液相を形成し、
焼結体の緻密化が進行すると同時に還元されたアルミニ
ウムは窒素と反応して窒化アルミニウムとなる。
CaCN 2” Ca+ C+ N 2 Of these, carbon reacts with oxygen and is removed from the molded body as Co gas or CO2 gas, and calcium also takes away oxygen and reacts with alumina to form a liquid phase as Ca0.2A1203. death,
At the same time as the densification of the sintered body progresses, the reduced aluminum reacts with nitrogen to become aluminum nitride.

C1CN2+3AbOs→CnO・2A1zOs”2A
IN+CO更に、焼成を充分に行なうことにより余分な
カルシウムシアナミドは容易に分解・揮散可能であり、
粒界相も易蒸発性のため、窒化アルミニウム焼結体中か
ら飛散する。これと同時に窒化アルミニウム粒子が成長
して不純物の原因ともなる粒界相はほとんど消滅して高
熱伝導性の窒化アルミニウムが得られる。
C1CN2+3AbOs→CnO・2A1zOs”2A
IN+CO Furthermore, by performing sufficient calcination, excess calcium cyanamide can be easily decomposed and volatilized.
The grain boundary phase also evaporates easily, so it scatters from the aluminum nitride sintered body. At the same time, aluminum nitride particles grow, and the grain boundary phase that causes impurities almost disappears, yielding aluminum nitride with high thermal conductivity.

ところが、カルシウムシアナミドは分解・揮散し易いた
め、焼成時に焼結体が緻密化する前に表面付近の焼結助
剤が飛び出してしまうため、表面付近が緻密化せず、そ
れによって熱伝導率が低下し、更に、形状によっては変
形が著しいという問題があった。
However, since calcium cyanamide easily decomposes and volatilizes, the sintering aid near the surface jumps out before the sintered body becomes densified during firing, so the sintering agent near the surface does not become densified and the thermal conductivity decreases. Furthermore, depending on the shape, deformation may be significant.

[問題点を解決するための手段] 従って、本発明は窒化アルミニウム粉末にカルシウムシ
アナミドを添加・混合し、得られた混合物を成形し、得
られた成形体を窒化アルミニウム粉末にカルシウム含有
化合物を添加してなる混合粉末で覆い非酸化性雰囲気中
で常圧焼成するか、または得られた成形体を常圧を超え
、50kg/em2までの窒素圧の窒素または窒素と不
活性ガスの混合ガス中で焼成するか、または得られた成
形体を前記混合粉末で覆い且つ常圧を超え、50ky/
cm2までの麗素圧の窒素または窒素と不活性ガスの混
合ガス中で焼成することを特徴とする窒化アルミニウム
焼結体の製造方法を提供するにある。
[Means for Solving the Problems] Therefore, the present invention involves adding and mixing calcium cyanamide to aluminum nitride powder, molding the resulting mixture, and molding the resulting molded body by adding a calcium-containing compound to the aluminum nitride powder. Either covered with a mixed powder made of powder and calcined at normal pressure in a non-oxidizing atmosphere, or the obtained molded body is heated above normal pressure in nitrogen or a mixed gas of nitrogen and an inert gas at a nitrogen pressure of up to 50 kg/em2. Alternatively, the obtained molded body is covered with the mixed powder and heated above normal pressure to 50ky/
An object of the present invention is to provide a method for producing an aluminum nitride sintered body, which is characterized by firing in nitrogen or a mixed gas of nitrogen and an inert gas at a pressure of up to 1 cm2.

[作 用コ 窒化アルミニウム粉末に焼結助剤としてカルシウムシア
ナミド(CaCN 2ンを添加・混合する。この焼結助
剤は難焼結性物質である窒化アルミニウムの焼結を促進
すると共に原料すなわち窒化アルミニウム粉末中の酸素
Iを低減することができ、この結果として、窒化アルミ
ニウム焼結体の熱伝導度を著しく増大させることができ
る。特に、カルシウムシアナミドの添加量を0,01〜
7.0重量%にすることにより、焼結体密度もあがり、
熱伝導率も60W/iK(室温)以上とすることができ
る。カルシウムシアナミドの添加量が7.0重量%を超
えると、急激に焼結体密度が下がり、熱伝導率が低下す
るために好ましくない、この理由は、焼結助剤が過剰に
なると、反応に寄与しないカーボンが窒化アルミニウム
の粒間に残留して焼結を阻害するためであると思われる
[Operation] Calcium cyanamide (CaCN2) is added and mixed as a sintering aid to the aluminum nitride powder. This sintering aid accelerates the sintering of aluminum nitride, which is a difficult-to-sinter substance, and also promotes the sintering of aluminum nitride, which is a material that is difficult to sinter. Oxygen I in the aluminum powder can be reduced, and as a result, the thermal conductivity of the aluminum nitride sintered body can be significantly increased.In particular, when the amount of calcium cyanamide added is 0.01~
By setting it to 7.0% by weight, the density of the sintered body also increases,
The thermal conductivity can also be 60 W/iK (room temperature) or higher. If the amount of calcium cyanamide added exceeds 7.0% by weight, the density of the sintered body will rapidly decrease and the thermal conductivity will decrease, which is undesirable. This seems to be because carbon that does not contribute remains between the grains of aluminum nitride and inhibits sintering.

本発明に使用する焼結助剤は空気中の水分と徐々に反応
して酸化物に変化するが、非水溶媒中では安定であり、
焼結助剤添加後の混合・粉砕操作は非水溶媒中で行なう
ことが好ましい。前述のCa C2やYC2よりも空気
中で安定であり、特に、Ca C2に見られるような爆
発の危険性は全くなく、取り扱いが容易であり、また、
Y C2に比べて非常に安価である。
The sintering aid used in the present invention gradually reacts with moisture in the air and turns into an oxide, but is stable in non-aqueous solvents.
The mixing and pulverizing operations after addition of the sintering aid are preferably performed in a non-aqueous solvent. It is more stable in air than the above-mentioned Ca C2 and YC2, and in particular, there is no danger of explosion as seen in Ca C2, and it is easy to handle.
It is much cheaper than YC2.

窒化アルミニウム粉末にカルシウムシアナミドを添加後
、混合・粉砕する時間は原料粉末の粒度により異なるが
、数十分から数十時間を要する。
After adding calcium cyanamide to aluminum nitride powder, the time for mixing and pulverizing varies depending on the particle size of the raw material powder, but it takes from several tens of minutes to several tens of hours.

この際、上述の理由からアセトンやトリクロロエタン等
の非水溶媒を添加することが好適であり、窒素ガス置換
を行なうことが更に好ましい。非水溶媒と使用する場合
には、混合・粉砕後、非水溶媒を真空または減圧下で加
熱・乾燥するのが迅速で望ましい。
At this time, for the above-mentioned reasons, it is preferable to add a non-aqueous solvent such as acetone or trichloroethane, and it is more preferable to perform nitrogen gas substitution. When used with a non-aqueous solvent, it is desirable to quickly heat and dry the non-aqueous solvent under vacuum or reduced pressure after mixing and pulverizing.

得られた混合粉体を室温で加圧プレスして所定の形状に
成形する。成形後、0.5〜5トン/CII+2で静水
圧加圧を行なうと、焼成後の焼結体が均一になり望まし
い。
The obtained mixed powder is pressurized at room temperature and molded into a predetermined shape. After molding, it is preferable to apply hydrostatic pressure at 0.5 to 5 tons/CII+2 to make the sintered body uniform after firing.

本発明の焼成工程の第1の方法は得られた成形体を窒化
アルミニウムにカルシウム含有化合物を添加してなる混
合粉末で覆い、これを常圧で焼成することよりなる。こ
れにより、表面付近の焼結助剤の揮散を防止することが
でき、その結果、変形のない、表面まで均質に焼けた窒
化アルミニウム焼結体を得ることができた。
The first method of the firing step of the present invention consists of covering the obtained molded body with a mixed powder made by adding a calcium-containing compound to aluminum nitride, and firing this at normal pressure. This made it possible to prevent the sintering aid near the surface from volatilizing, and as a result, it was possible to obtain an aluminum nitride sintered body that was uniformly burnt to the surface without deformation.

カルシウム含有化合物としては特にカルシウムシアナミ
ドが好ましいが、CaO1CaC○1等のCaの蒸気が
あがるものであれば、いずれのものでも使用することが
できる。カルシウム含有化合物の窒化アルミニウムへの
添加量は成形体中のCaiに対して等圧になる呈が好ま
しいが、やや過剰でも、また、極微量でも充分に効果が
ある。
Calcium cyanamide is particularly preferred as the calcium-containing compound, but any compound that releases Ca vapor, such as CaO1CaC○1, can be used. The amount of the calcium-containing compound added to the aluminum nitride is preferably such that the pressure is equal to that of Cai in the compact, but even a slight excess or a very small amount is sufficiently effective.

ただし、カルシウム含有化合物を大過剰に加えた場合だ
けは、焼結助剤の濃度が濃くなりすぎて、焼結を阻害し
、多孔質の焼結体を生じ、熱伝導度が著しく低下する。
However, only when a large excess of the calcium-containing compound is added, the concentration of the sintering aid becomes too high, inhibiting sintering, producing a porous sintered body, and significantly reducing thermal conductivity.

成形体を覆う混合粉末の粒度は特に限定されるものでは
ないが、成形体の形状が比較的複雑な場合あるいは焼結
時の変形を特に抑える必要がある場合には、比較的細か
い粒径を用いることが望ましい、しかし、混合粉末の粒
径が細か過ぎると、かえって覆っている粉同志が強固に
焼結したり、焼結体に固着することもあり、好ましくな
い、一方、成形体の形状が単純な場合には、混合1ガ末
は粗い粒子の方が焼結体に固着しに<<、焼結時に不要
となった粒界相や焼結助剤を焼結体から飛散させ易く好
ましい。焼成時の雰囲気としては窒素ガス、水素ガス、
−酸化炭素ガスまたは不活性ガスのような非酸化性雰囲
気が良く、特に窒素ガス雰囲気が良好である。酸化性雰
囲気では、窒化アルミニウムが酸化してしまい、緻密な
焼結体が得られない。
The particle size of the mixed powder that covers the compact is not particularly limited, but if the shape of the compact is relatively complex or it is necessary to particularly suppress deformation during sintering, a relatively fine particle size may be used. However, if the particle size of the mixed powder is too small, the covering powders may sinter strongly or stick to the sintered body, which is undesirable. In the case of a simple case, the coarser particles of the mixture 1 powder tend to stick to the sintered body <<, and the grain boundary phase and sintering aid that are no longer needed during sintering are easier to scatter from the sintered body. preferable. The atmosphere during firing is nitrogen gas, hydrogen gas,
- A non-oxidizing atmosphere such as carbon oxide gas or an inert gas is preferred, and a nitrogen gas atmosphere is particularly preferred. In an oxidizing atmosphere, aluminum nitride is oxidized and a dense sintered body cannot be obtained.

本発明の焼成工程の第2の方法は上述のように  □し
て得られた成形体を常圧を超え、50kg/c+n2の
窒素圧の窒素または窒素と不活性ガスの混合ガス中で焼
成するものである。この方法も焼結助剤であるカルシウ
ムシアナミドの分解・揮散を抑制するために行なわれる
ものであるが、窒素圧の低い方では若干の変形を生ずる
こともあるが、この方法によれば、カルシウムシアナミ
ドの分解・飛散を充分に抑制することができ、窒化アル
ミニウム焼結体の変形量をかなり少なくすることができ
る。また、第1の方法のように成形体を覆う混合粉末が
窒化アルミニウム焼結体に固着してしまうような心配は
全くない。しかし、窒素圧が50kg/cm2を超えて
も、カルシウムシアナミドの分解・飛散を抑制する効果
は余り改善されず、装置的な困難が付随するために好ま
しくない。
The second method of the firing process of the present invention is to fire the molded body obtained by □ above in nitrogen or a mixed gas of nitrogen and inert gas at a nitrogen pressure of 50 kg/c+n2 above normal pressure. It is something. This method is also used to suppress the decomposition and volatilization of calcium cyanamide, which is a sintering aid, but slight deformation may occur at low nitrogen pressures; The decomposition and scattering of cyanamide can be sufficiently suppressed, and the amount of deformation of the aluminum nitride sintered body can be considerably reduced. Further, unlike the first method, there is no fear that the mixed powder covering the molded body will stick to the aluminum nitride sintered body. However, even if the nitrogen pressure exceeds 50 kg/cm2, the effect of suppressing the decomposition and scattering of calcium cyanamide is not significantly improved, and equipment-related difficulties are involved, which is not preferable.

本発明の焼成工程の第3の方法としては、第1の方法と
第2の方法を併用するものである。この方法により得ら
れた窒化アルミニウム焼結体は変形もなく、均質なもの
である。また、第1の方法及び第2の方法に比べて焼結
助剤の添加量が非常に少ない場合でも、より緻密であり
、熱伝導率の向上も見られた。
The third method of the firing step of the present invention is a combination of the first method and the second method. The aluminum nitride sintered body obtained by this method is homogeneous without deformation. In addition, even when the amount of sintering aid added was very small compared to the first method and the second method, it was more dense and improved thermal conductivity was also observed.

上述の3種の焼成手段は成形体の形状、得られる窒化ア
ルミニウム焼結体の用途等に応じて適宜選択することが
できる。
The above-mentioned three types of firing means can be appropriately selected depending on the shape of the compact, the use of the resulting aluminum nitride sintered body, and the like.

焼成温度は1500〜2200℃、好ましくは1600
〜2100℃で行なうことができるが、温度範囲はこれ
らに限定されるものではないことを理解されたい。
Firing temperature is 1500-2200℃, preferably 1600℃
It is to be understood that temperature ranges are not limited to, but can be carried out at -2100<0>C.

また、焼成時間は焼成温度に依存するものであり、特に
限定されるものではない。
Further, the firing time depends on the firing temperature and is not particularly limited.

[実 施 例] 以下に実施例を挙げ、本発明を更に説明する。[Example] The present invention will be further explained with reference to Examples below.

夫l」ロ一 本実施例では成形体を混合粉末で覆う第1の焼成方法を
使用して窒化アルミニウム焼結体を得た。
In this example, an aluminum nitride sintered body was obtained using the first firing method in which the compact was covered with mixed powder.

成形体及び混合粉末の組成、焼成温度及び得られた窒化
アルミニウム焼結体の特性を第1表に記載する。なお、
成形体の成形圧は2トン/c1112であり、焼成時間
は2時間であり、焼成雰囲気は常圧の窒素ガス雰囲気で
あった。
Table 1 shows the compositions of the molded body and mixed powder, the firing temperature, and the properties of the obtained aluminum nitride sintered body. In addition,
The molding pressure of the compact was 2 tons/c1112, the firing time was 2 hours, and the firing atmosphere was a nitrogen gas atmosphere at normal pressure.

上述の第1表からも明らかなように、本発明品は変形が
なく、表面まで均質に焼成することができ、熱伝導率も
向上していた。
As is clear from Table 1 above, the products of the present invention were not deformed, could be fired uniformly to the surface, and had improved thermal conductivity.

及W工 実施例1では成形体と混合粉末を同一組成として焼成を
行なったが、本実施例では成形体の組成と混合粉末の組
成を種々変化させ、実施例1と同様の操作を行なうこと
により窒化アルミニウム焼結体を得た。成形体の組成、
混合粉末の組成、焼成温度及び得られた窒化アルミニウ
ム焼結体の特性を以下の第2表に記載する。
In Example 1, the molded body and the mixed powder were fired with the same composition, but in this example, the composition of the molded body and the mixed powder were varied, and the same operations as in Example 1 were performed. An aluminum nitride sintered body was obtained. Composition of the molded body,
The composition of the mixed powder, the firing temperature, and the properties of the obtained aluminum nitride sintered body are listed in Table 2 below.

寒m 混合粉末のカルシウム含有化合物として以下の第3表に
記載する化合物を用いた以外は実施例1と同様の操作を
行なうことによって窒化アルミニウム焼結体を得る。な
お、本実施例において、焼成温度は1900℃であり、
焼成時間は2時間であり、焼成雰囲気は常圧の窒素ガス
雰囲気であった。成形体の組成、混合粉末の組成及び得
られた窒化アルミニウム焼結体の相対密度を以下の第3
表に記載する。
An aluminum nitride sintered body was obtained by carrying out the same operations as in Example 1, except that the compounds listed in Table 3 below were used as the calcium-containing compounds of the mixed powder. In addition, in this example, the firing temperature was 1900 ° C.
The firing time was 2 hours, and the firing atmosphere was a nitrogen gas atmosphere at normal pressure. The composition of the molded body, the composition of the mixed powder, and the relative density of the obtained aluminum nitride sintered body were determined as follows.
Record in the table.

夾1」しL 本実施例では焼成時に窒素圧を掛ける第2の焼成方法を
使用して窒化アルミニウム焼結体を得た。
In this example, an aluminum nitride sintered body was obtained using the second firing method in which nitrogen pressure was applied during firing.

成形体の組成、焼成条件及び得られた窒化アルミニウム
焼結体の特性を第4表に記載する。なお、成形体の成形
圧は2トン/cm2であり、焼成時間は2時間であった
The composition of the molded body, the firing conditions, and the properties of the obtained aluminum nitride sintered body are listed in Table 4. The molding pressure of the molded body was 2 tons/cm2, and the firing time was 2 hours.

犬1j[[ 本実施例では成形体を混合粉末で覆い且つ焼成時に窒素
圧を掛ける第3の焼成方法を使用して窒化アルミニウム
焼結体を得た。成形体及び混合粉末の組成、焼成条件及
び得られた窒化アルミニウム焼結体の特性を第5表に記
載する。なお、成形体の成形圧は2トン/am2であり
、焼成時間は2時間であった。
In this example, an aluminum nitride sintered body was obtained using the third firing method in which the molded body was covered with mixed powder and nitrogen pressure was applied during firing. Table 5 shows the compositions of the compact and mixed powder, the firing conditions, and the properties of the obtained aluminum nitride sintered body. The molding pressure of the molded body was 2 tons/am2, and the firing time was 2 hours.

[発明の効果] 本発明方法によれば、変形がなく、また、カルシウムシ
アナミドの分解・飛散により焼結体表面が多孔質となら
ず、熱伝導率の良好な窒化アルミニウム焼結体を得るこ
とができる。また、変形がなく且つ多孔質となることが
ないために、従来の窒化アルミニウム焼結体のように品
質の良好な部分のみを切り出して使用する必要もなく、
所定の形状に成形して得られた窒化アルミニウム焼成体
をそのまま使用することができる。
[Effects of the Invention] According to the method of the present invention, it is possible to obtain an aluminum nitride sintered body that does not undergo deformation, does not have the surface of the sintered body porous due to decomposition and scattering of calcium cyanamide, and has good thermal conductivity. Can be done. In addition, because it does not deform or become porous, there is no need to cut out and use only high-quality parts unlike conventional aluminum nitride sintered bodies.
The aluminum nitride fired body obtained by molding into a predetermined shape can be used as is.

Claims (1)

【特許請求の範囲】 1、窒化アルミニウム粉末にカルシウムシアナミドを添
加・混合し、得られた混合物を成形し、得られた成形体
を窒化アルミニウム粉末にカルシウム含有化合物を添加
してなる混合粉末で覆い非酸化性雰囲気中で常圧焼成す
るか、または得られた成形体を常圧を超え、50kg/
cm^2までの窒素圧の窒素または窒素と不活性ガスの
混合ガス中で焼成するか、または得られた成形体を前記
混合粉末で覆い且つ常圧を超え、50kg/cm^2ま
での窒素圧の窒素または窒素と不活性ガスの混合ガス中
で焼成することを特徴とする窒化アルミニウム焼結体の
製造方法。 2、カルシウムシアナミドの添加量が0.01〜7重量
%である特許請求の範囲第1項記載の窒化アルミニウム
の製造方法。 3、カルシウム含有化合物がカルシウムシアナミドであ
る特許請求の範囲第1項記載の窒化アルミニウムの製造
方法。
[Claims] 1. Adding and mixing calcium cyanamide to aluminum nitride powder, molding the resulting mixture, and covering the resulting molded body with a mixed powder obtained by adding a calcium-containing compound to aluminum nitride powder. Calcinate at normal pressure in a non-oxidizing atmosphere, or press the obtained molded product above normal pressure at 50kg/
Either by firing in nitrogen or a mixture of nitrogen and an inert gas at a nitrogen pressure of up to cm^2, or by covering the obtained compact with the above-mentioned mixed powder and at a nitrogen pressure of up to 50 kg/cm^2 above normal pressure. A method for producing an aluminum nitride sintered body, which comprises firing in high pressure nitrogen or a mixed gas of nitrogen and an inert gas. 2. The method for producing aluminum nitride according to claim 1, wherein the amount of calcium cyanamide added is 0.01 to 7% by weight. 3. The method for producing aluminum nitride according to claim 1, wherein the calcium-containing compound is calcium cyanamide.
JP62099994A 1987-04-24 1987-04-24 Production of aluminum nitride sintered body Pending JPS63265865A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62099994A JPS63265865A (en) 1987-04-24 1987-04-24 Production of aluminum nitride sintered body

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62099994A JPS63265865A (en) 1987-04-24 1987-04-24 Production of aluminum nitride sintered body

Publications (1)

Publication Number Publication Date
JPS63265865A true JPS63265865A (en) 1988-11-02

Family

ID=14262187

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62099994A Pending JPS63265865A (en) 1987-04-24 1987-04-24 Production of aluminum nitride sintered body

Country Status (1)

Country Link
JP (1) JPS63265865A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02217363A (en) * 1989-02-20 1990-08-30 Denki Kagaku Kogyo Kk Production of ain sintered compact having high heat conductivity

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02217363A (en) * 1989-02-20 1990-08-30 Denki Kagaku Kogyo Kk Production of ain sintered compact having high heat conductivity

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