JP2671986B2 - Oxidation resistant aluminum nitride powder and manufacturing method thereof - Google Patents
Oxidation resistant aluminum nitride powder and manufacturing method thereofInfo
- Publication number
- JP2671986B2 JP2671986B2 JP62216507A JP21650787A JP2671986B2 JP 2671986 B2 JP2671986 B2 JP 2671986B2 JP 62216507 A JP62216507 A JP 62216507A JP 21650787 A JP21650787 A JP 21650787A JP 2671986 B2 JP2671986 B2 JP 2671986B2
- Authority
- JP
- Japan
- Prior art keywords
- aluminum nitride
- nitride powder
- weight
- aluminum
- oxidation resistance
- 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 - Fee Related
Links
Landscapes
- Ceramic Products (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、酸素含有量が少い焼結性にすぐれた金属ア
ルミニウム直接窒化法による窒化アルミニウム粉末の製
造方法に関する。
〔従来の技術〕
窒化アルミニウム粉末は、Al2O3還元法と金属アルミ
ニウム直接窒化法で製造されるものが知られている。前
者の窒化アルミニウム粉末は耐酸化性にすぐれ高純度の
可能性を持つ長所を有するが、工業的規模に於いてコス
ト高であるという欠点がある。一方、後者の窒化アルミ
ニウム粉末は工業的に低コストで製造可能であるが、窒
化アルミニウム粉末表面が加水分解し易く、製造工程特
に粉砕工程と取り扱い中に酸素含有量が増加する欠点が
ある。窒化アルミニウム粉末の用途としては高熱導性基
板が主体であり、酸素含有量の多い窒化アルミニウム粉
末を使用し焼結せしめた製品は熱伝導率が低下するとが
一般的に言われている。金属アルミニウム直接窒化法に
よる窒化アルミニウム粉末の表面安定化ないし低酸素化
は非常に難しく、現在まで酸素含有量が0.8重量％以下
の該粉末は得られていない。
一方、窒化アルミニウム粉末の酸化防止を行うため
に、パラフインやステアリン酸を添加したり、ポリビニ
ルブチラールで顆粒にしたりすることが提案されている
が（特開昭62−119167号公報）、窒化アルミニウム粉末
が金属アルミニウム直接窒化法である場合の処理条件は
示されていない。また、この方法は、全て溶剤中での処
理であり、工業的に不利である。
〔発明が解決しようとする問題点〕
本発明は金属アルミニウム直接窒化法で得られた窒化
アルミニウム粉末の表面改質ないし低酸素化であつて、
その目的とするところは、耐酸化性のすぐれた窒化アル
ミニウム粉末を提供することにある。
〔問題点を解決するための手段〕
すなわち、本発明は、金属アルミニウム直接窒化法で
製造された窒化アルミニウムイゴットの粗砕物100重量
部に脂肪族カルボン酸及び／又はその塩からなる界面活
性剤0.05〜２重量部を添加し製品粒径に粉砕した後、温
度100〜200℃で加熱処理することを特徴とする、耐酸化
性指標が２重量％以下であり親水性を有する窒化アルミ
ニウム粉末の製造方法である。なお、ここで耐酸化性指
標とは、窒化アルミニウム粉末を水中で１時間撹拌した
際の増量酸素（重量％）を意味し、その測定は市販の酸
素分析計を用いて行うことができる。
以下、更に詳しくは本発明について説明する。
本発明で製造される窒化アルミニウム粉末は、金属ア
ルミニウムを窒化して製造されたインゴットの粗砕物
に、ステアリン酸、オレイン酸等の脂肪族カルボン酸及
び／又はその塩からなる界面活性剤を添加し、そのイン
ゴットを製品粒径に粉砕したものであって、その耐酸化
性指標が２重量％以下であり、しかも親水性を有するも
のである。
耐酸化性指標が２重量％を越えると、焼結体特性、特
に熱伝導率と強度発現に悪影響を及ぼす。更には、プレ
ス成形とスリップ成形をすることが困難となり、またシ
ート成形の場合にはアンモニア臭により作業環境が悪化
する。一方、親水性がないと水系のスリップ成形に適さ
なくなる。
本発明の粉砕原料である窒化アルミニウムインゴット
の粗砕物は、常法に従い、金属アルミニウムを窒化して
窒化アルミニムインゴットを製造し、それをジョークラ
ッシャー等の粗砕機で粒径10mm以下程度に粗砕すること
によって製造することができる。
本発明は、このような窒化アルミニウムインゴット粗
砕物100重量部に、ステアリン酸、オレイン酸等の脂肪
族カルボン酸及び／又はその塩からなる界面活性剤0.05
〜２重量部を添加し製品粒径に粉砕した後、温度100〜2
00℃で加熱処理するものである。
界面活性剤の添加量が0.05重量部未満では、耐酸化性
が向上せずに従来のアンモニア臭を漂わせる窒化アンモ
ニウム粉末が製造される。また、２重量部を越えて添加
しても耐酸化性はそれほど向上せず、かえってそれを熱
処理して失活させるのに長時間が必要となる。界面活性
剤の多量の残留は、窒化アンモニウム粉末の成形性と焼
結性に悪影響を及ぼす。
本発明においては、この界面活性剤の添加によって窒
化アルミニウムインゴット粗砕物の粉砕性が向上し、も
って粉砕中に表面酸素が増加するのを低減し耐酸化性に
すぐれた窒化アルミニウム粉末を製造することができ
る。窒化アルミニウム粉末の製品粒径は用途に応じて自
由に設計することができるが、通常は平均粒径で数μｍ
以下である。
上記で得られた窒化アルミニウムインゴット粗砕物の
粉砕物は、次いで100〜200℃の温度で加熱処理されて界
面活性剤の疎水基が分解されて安定化されて本発明の窒
化アルミニウム粉末となる。加熱温度が200℃を越える
と耐酸化性の向上は望めず、また100℃未満では親水性
に劣る。加熱雰囲気は、空気中が望ましい。
〔実施例〕
次に本発明を実施例をあげて説明する。
実施例１
最大粒径が1mmの窒化アルミニウムのインゴツト粗砕
物100重量部にステアリン酸１重量部を添加し、ボール
ミルを用いて５時間粉砕・混合後、150℃で１時間加熱
し安定化窒化アルミニウム粉末を調整した。得られた窒
化アルミニウム粉末について、親水性、耐酸化性指標及
び平均粒径を測定した。その結果を表に示す。
実施例２〜9,比較例１〜５
窒化アルミニウム粉末の種類、界面活性剤の種類及び
添加量、更には界面活性剤の安定化条件を種々に変え
て、実施例１と同様にして安定化窒化アルミニウム粉末
を調整し、それぞれについて、親水性、耐酸化性指標及
び平均粒径を測定した。その結果を表に示す。
なお、表に記載した測定値の測定は次の方法によつ
た。
（１）酸素（重量％）:LECO社TC−136型酸素分析計によ
る。
（２）平均粒径（μｍ）:Fisher社のFSSS法による。
（３）親水性:1リットルの水と100gの窒化アルミニウム
粉末を10分間撹拌した後、水に浮かんだ窒化アルミニウ
ム粉末の割合を測定し、それが10重量％未満を「良
好」、10重量％以上を「水に浮く」とした。〔発明の効果〕
本発明の窒化アルミニウム粉末を用いれば、窒化アル
ミニウム本体を特性を損うことなく工業的規模に利用で
き、結果的に品質向上並びに成形コストを大幅に改善さ
せることができる。特に、水系のスリツプ成形に適した
粉末である。Description: TECHNICAL FIELD The present invention relates to a method for producing aluminum nitride powder by a direct metal nitriding method of aluminum metal having a low oxygen content and excellent in sinterability. [Prior Art] Aluminum nitride powder is known to be produced by an Al 2 O 3 reduction method and a metal aluminum direct nitriding method. The former aluminum nitride powder has the advantage of being excellent in oxidation resistance and having the possibility of high purity, but has the drawback of being costly on an industrial scale. On the other hand, the latter aluminum nitride powder can be industrially produced at low cost, but it has a drawback that the surface of the aluminum nitride powder is easily hydrolyzed and the oxygen content increases during the production process, particularly the pulverization process and handling. It is generally said that aluminum nitride powder is mainly used for high thermal conductivity substrates, and that the product obtained by sintering aluminum nitride powder having a high oxygen content has a low thermal conductivity. It is very difficult to stabilize the surface or reduce the oxygen content of the aluminum nitride powder by the direct aluminum nitriding method of metal aluminum, and the powder having an oxygen content of 0.8% by weight or less has not been obtained so far. On the other hand, in order to prevent oxidation of the aluminum nitride powder, it has been proposed to add paraffin or stearic acid or to granulate with polyvinyl butyral (Japanese Patent Laid-Open No. 62-119167), but aluminum nitride powder The processing conditions are not shown when the is a direct aluminum nitriding method. Further, this method is all industrially disadvantageous because it is carried out in a solvent. [Problems to be Solved by the Invention] The present invention relates to surface modification or oxygen reduction of an aluminum nitride powder obtained by a metal aluminum direct nitriding method,
The purpose is to provide an aluminum nitride powder having excellent oxidation resistance. [Means for Solving Problems] That is, the present invention relates to a surfactant comprising an aliphatic carboxylic acid and / or a salt thereof in 100 parts by weight of a coarsely ground product of an aluminum nitride ingot produced by a direct aluminum nitriding method. A hydrophilic aluminum nitride powder having an oxidation resistance index of 2% by weight or less, which is characterized by adding 0.05 to 2 parts by weight and pulverizing to a product particle size, and then heat-treating at a temperature of 100 to 200 ° C. It is a manufacturing method. The term "oxidation resistance index" as used herein means increased oxygen (wt%) when the aluminum nitride powder is stirred in water for 1 hour, and the measurement can be performed using a commercially available oxygen analyzer. Hereinafter, the present invention will be described in more detail. The aluminum nitride powder produced in the present invention is obtained by adding a surfactant composed of an aliphatic carboxylic acid such as stearic acid and oleic acid and / or a salt thereof to a coarsely crushed ingot produced by nitriding metallic aluminum. The ingot is crushed to a product particle size, the oxidation resistance index is 2% by weight or less, and it has hydrophilicity. If the oxidation resistance index exceeds 2% by weight, the properties of the sintered body, particularly the thermal conductivity and strength development are adversely affected. Furthermore, it becomes difficult to perform press molding and slip molding, and in the case of sheet molding, the work environment becomes worse due to the smell of ammonia. On the other hand, if it is not hydrophilic, it will not be suitable for aqueous slip molding. The crushed material of the aluminum nitride ingot, which is the crushing raw material of the present invention, is manufactured by an ordinary method to produce an aluminum nitride ingot by nitriding metal aluminum, and crushed it into a particle size of 10 mm or less with a crusher such as a jaw crusher. Can be manufactured. The present invention is based on 100 parts by weight of such an aluminum nitride ingot crushed product, and a surfactant containing an aliphatic carboxylic acid such as stearic acid and oleic acid, and / or a salt thereof in a 0.05
After adding ~ 2 parts by weight and crushing to product particle size, the temperature is 100 ~ 2
It is heat treated at 00 ° C. When the amount of the surfactant added is less than 0.05 parts by weight, the conventional ammonium nitride powder which does not improve the oxidation resistance and has a conventional ammonia odor can be produced. Further, even if added in an amount of more than 2 parts by weight, the oxidation resistance does not improve so much, and on the contrary, it takes a long time to heat and deactivate it. A large amount of residual surfactant adversely affects the formability and sinterability of the ammonium nitride powder. In the present invention, the pulverizability of the aluminum nitride ingot crushed product is improved by the addition of this surfactant, and thus it is possible to reduce the increase of surface oxygen during pulverization and to produce an aluminum nitride powder excellent in oxidation resistance. You can The product particle size of aluminum nitride powder can be freely designed according to the application, but usually the average particle size is several μm.
It is as follows. The pulverized material of the aluminum nitride ingot crushed product obtained above is then heat-treated at a temperature of 100 to 200 ° C. to decompose and stabilize the hydrophobic group of the surfactant to be the aluminum nitride powder of the present invention. If the heating temperature exceeds 200 ° C, improvement in oxidation resistance cannot be expected, and if it is less than 100 ° C, the hydrophilicity is poor. The heating atmosphere is preferably air. EXAMPLES Next, the present invention will be described with reference to examples. Example 1 1 part by weight of stearic acid was added to 100 parts by weight of a crushed ingot of aluminum nitride having a maximum particle size of 1 mm, and the mixture was crushed and mixed for 5 hours in a ball mill, and then heated at 150 ° C. for 1 hour to stabilize aluminum nitride. The powder was prepared. The hydrophilicity, oxidation resistance index and average particle size of the obtained aluminum nitride powder were measured. The results are shown in the table. Examples 2-9, Comparative Examples 1-5 Stabilization in the same manner as in Example 1 by changing the type of aluminum nitride powder, the type and amount of surfactant added, and the stabilizing conditions for the surfactant. The aluminum nitride powder was prepared, and the hydrophilicity, the oxidation resistance index, and the average particle size were measured for each. The results are shown in the table. In addition, the measurement of the measured value described in the table was performed by the following method. (1) Oxygen (% by weight): by LECO TC-136 type oxygen analyzer. (2) Average particle size (μm): FSSS method by Fisher. (3) Hydrophilicity: After stirring 1 liter of water and 100 g of aluminum nitride powder for 10 minutes, the ratio of the aluminum nitride powder floating in water was measured, and when it was less than 10% by weight, “good”, 10% by weight The above is "floating in water". [Effects of the Invention] By using the aluminum nitride powder of the present invention, the aluminum nitride main body can be used on an industrial scale without deteriorating the characteristics, and as a result, quality improvement and molding cost can be greatly improved. In particular, the powder is suitable for water-based slip molding.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 中島 征彦 福岡県大牟田市新開町１ 電気化学工業 株式会社大牟田工場内 審査官 大工原 大二 (56)参考文献 特開 昭63−225507（ＪＰ，Ａ) 特開 昭62−207770（ＪＰ，Ａ) ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masahiko Nakajima 1 Shinkaimachi, Omuta City, Fukuoka Prefecture Electrochemical Industry Omuta Factory Co., Ltd. Examiner Daiji Hara (56) References JP-A-63-225507 (JP, A) JP-A-62-207770 (JP, A)
Claims (1)
ミニウムインゴットの粗砕物100重量部に脂肪族カルボ
ン酸及び／又はその塩からなる界面活性剤0.05〜２重量
部を添加し製品粒径に粉砕した後、温度100〜200℃で加
熱処理することを特徴とする、耐酸化性指標が２重量％
以下であり親水性を有する窒化アルミニウム粉末の製造
方法。(57) [Claims] To 100 parts by weight of an aluminum nitride ingot produced by the direct nitriding method of metallic aluminum, 0.05 to 2 parts by weight of a surfactant composed of an aliphatic carboxylic acid and / or a salt thereof was added, and the mixture was crushed to a product particle size and then the temperature. 2% by weight of oxidation resistance index, characterized by heat treatment at 100-200 ℃
The following is a method for producing a hydrophilic aluminum nitride powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62216507A JP2671986B2 (en) | 1987-09-01 | 1987-09-01 | Oxidation resistant aluminum nitride powder and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62216507A JP2671986B2 (en) | 1987-09-01 | 1987-09-01 | Oxidation resistant aluminum nitride powder and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6461304A JPS6461304A (en) | 1989-03-08 |
| JP2671986B2 true JP2671986B2 (en) | 1997-11-05 |
Family
ID=16689509
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62216507A Expired - Fee Related JP2671986B2 (en) | 1987-09-01 | 1987-09-01 | Oxidation resistant aluminum nitride powder and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2671986B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE59305440D1 (en) * | 1992-09-08 | 1997-03-27 | Hoechst Ag | Process for the preparation of water-sensitive ceramic powders into a free-flowing granulated powder |
| US5352424A (en) * | 1993-02-16 | 1994-10-04 | The Dow Chemical Company | Aluminum nitride powder having a reduced ammonia odor and a method for preparing the same |
| US5417887A (en) * | 1993-05-18 | 1995-05-23 | The Dow Chemical Company | Reduced viscosity, organic liquid slurries of aluminum nitride powder |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62207770A (en) * | 1986-03-06 | 1987-09-12 | 古河電気工業株式会社 | Aluminum nitride powder for manufacturing sintered body |
| JPS63225507A (en) * | 1987-03-16 | 1988-09-20 | Toyo Alum Kk | Aluminum nitride powder |
-
1987
- 1987-09-01 JP JP62216507A patent/JP2671986B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6461304A (en) | 1989-03-08 |
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