JP2946990B2 - Method for producing highly-fillable silicon nitride powder - Google Patents
Method for producing highly-fillable silicon nitride powderInfo
- Publication number
- JP2946990B2 JP2946990B2 JP5036163A JP3616393A JP2946990B2 JP 2946990 B2 JP2946990 B2 JP 2946990B2 JP 5036163 A JP5036163 A JP 5036163A JP 3616393 A JP3616393 A JP 3616393A JP 2946990 B2 JP2946990 B2 JP 2946990B2
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- JP
- Japan
- Prior art keywords
- silicon nitride
- powder
- nitride powder
- particles
- density
- 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
Description
【０００１】[0001]
【産業上の利用分野】本発明は、針状粒が非常に少な
く、充填性が高いため、高密度の成形体を得ることがで
きる窒化ケイ素粉末の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a silicon nitride powder capable of obtaining a high-density compact because it has a very small amount of acicular particles and a high filling property.
【０００２】[0002]
【従来の技術】近年、窒化ケイ素はその優れた耐熱性、
高強度、耐食性等の特性が注目されているが、その製品
化には従来より窒化ケイ素粉末と酸化物助剤等の粉末に
結合剤である有機バインダーを添加し、水等の媒体を用
いてスラリー化し、次いで顆粒化した後に加圧成形する
か、あるいはスラリーのまま鋳込成形することにより所
定の形状に成形し、これを脱脂後、焼結することが行わ
れている。2. Description of the Related Art In recent years, silicon nitride has excellent heat resistance,
Although properties such as high strength and corrosion resistance have attracted attention, their production has been achieved by adding an organic binder as a binder to powders such as silicon nitride powder and oxide auxiliary, and using a medium such as water. A slurry is formed, then granulated, and then subjected to pressure molding, or a slurry is cast into a predetermined shape by casting, degreased, and then sintered.
【０００３】この場合、スラリー化の際には、高濃度で
しかもスラリーを低粘度化することがその後の物性に良
好な結果を与えることが知られている。また、焼結前の
成形の段階では成形体の成形密度が高くなれば焼結の際
の密度が上がり、収縮が小さくなるので、焼結体の強度
や寸法精度の点で有利である。[0003] In this case, it is known that when the slurry is formed, a high concentration and a low viscosity of the slurry give good results in the subsequent physical properties. Further, in the molding stage before sintering, if the molding density of the molded body increases, the density during sintering increases and shrinkage decreases, which is advantageous in terms of strength and dimensional accuracy of the sintered body.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、従来、
金属ケイ素粉末の直接窒化法により得られた窒化ケイ素
粉末を用いて水を媒体としたスラリーを調製した場合、
高濃度低粘度化が困難であり、また、成形体を成形して
も成形密度が高くならず、このため高強度の焼結体を得
ることが困難であった。However, conventionally,
When a slurry using water as a medium is prepared using silicon nitride powder obtained by direct nitriding of metal silicon powder,
It was difficult to reduce the viscosity at a high concentration, and the molding density was not increased even when the molded body was molded, and therefore, it was difficult to obtain a high-strength sintered body.
【０００５】本発明は上記事情に鑑みなされたもので、
スラリー化の際、高濃度低粘度化が達成され、成形体の
成形密度を高くすることができ、このため焼結体の強度
や寸法精度を向上させることができる高充填性窒化ケイ
素粉末の製造方法を提供することを目的とする。[0005] The present invention has been made in view of the above circumstances,
Production of highly-filled silicon nitride powder that can achieve high concentration and low viscosity during slurrying, increase the molding density of the molded body, and thus improve the strength and dimensional accuracy of the sintered body The aim is to provide a method.
【０００６】[0006]
【課題を解決するための手段及び作用】本発明者らは、
上記目的を達成するため鋭意検討を重ねた結果、金属ケ
イ素粉末から直接窒化法により窒化ケイ素粉末を製造す
る際、１μｍ以下の粒子が５重量％以下の金属ケイ素粉
末を用いることにより、得られる窒化ケイ素粉末が針状
粒が非常に少なく水を媒体としたスラリーに調製した場
合に高濃度低粘度化できると共に、成形体の成形密度を
高くすることができることを知見した。Means and Action for Solving the Problems The present inventors have
As a result of intensive studies to achieve the above object, it has been found that, when silicon nitride powder is produced directly from metal silicon powder by a nitriding method, particles obtained by using metal silicon powder having particles of 1 μm or less and 5% by weight or less are obtained. It has been found that when the silicon powder is prepared into a slurry using water as a medium having very few needle-like particles, a high concentration and a low viscosity can be achieved and the molding density of the molded body can be increased.
【０００７】即ち、本発明者は、直接窒化法により得ら
れる窒化ケイ素には、一般に針状粒が多く、このためじ
ん肺等の問題のみならず、スラリー粘度を低くしたり、
成形体密度を低くする原因となっていることを知見し
た。このため、分級によりこの針状粒を除去することを
考えたが、この方法は窒化ケイ素粉末の収率が悪い上、
このように針状粒を分級により除去しただけでは高充填
性の窒化ケイ素が得られないものであった。That is, the present inventor has found that silicon nitride obtained by the direct nitridation method generally has many needle-like grains, which causes not only problems such as pneumoconiosis, but also a reduction in slurry viscosity,
It has been found that this is a cause of lowering the density of the compact. Therefore, it was considered to remove the needle-like particles by classification, but this method has a poor silicon nitride powder yield,
As described above, simply removing the needle-like particles by classification cannot provide highly-filled silicon nitride.
【０００８】そこで、本発明者らは、直接窒化法で針状
粒が少なく、充填密度の高い窒化ケイ素粉末を得る方法
を検討し、針状粒の生成に与える原料の金属ケイ素粉末
の影響について検討した結果、粒径１μｍ以下の微粉が
５重量％以下の金属ケイ素を原料とすると、針状粒の生
成が本質的に抑制され、これを粉砕後酸処理した窒化ケ
イ素もまた針状粒が少なくなり、これにより健康上の問
題がなくなる上、針状粒の除去処理を特に必要とせず、
窒化ケイ素を全量回収でき、しかも充填密度が高くなっ
て、２０００ｋｇ／ｃｍ2の圧力で冷間ラバープレス成
形法にて成形した成形体の密度が１．９０ｇ／ｃｍ3以
上、特に１．９５ｇ／ｃｍ3以上という従来得られなか
った高充填性窒化ケイ素粉末が得られることを見い出
し、本発明をなすに至ったものである。Therefore, the present inventors studied a method of obtaining a silicon nitride powder having a small packing density and a high packing density by a direct nitriding method, and examined the effect of the raw material metal silicon powder on the formation of the needle-shaped particles. As a result of investigation, when fine powder having a particle size of 1 μm or less is made of metallic silicon having a content of 5% by weight or less, the formation of needle-like particles is essentially suppressed. Less, which eliminates health problems, and does not require any particular removal of needle-like particles,
The entire amount of silicon nitride can be recovered, and the packing density is increased. The density of a compact formed by a cold rubber press molding method at a pressure of 2000 kg / cm 2 is 1.90 g / cm 3 or more, particularly 1.95 g / cm 2. The present inventors have found that a highly-fillable silicon nitride powder of cm 3 or more, which has not been obtained conventionally, can be obtained, which has led to the present invention.
【０００９】従って、本発明は、金属ケイ素粉末から直
接窒化法により窒化ケイ素粉末を製造する方法におい
て、１μｍ以下の粒子が５重量％以下の金属ケイ素粉末
を用いることを特徴とする高充填性窒化ケイ素粉末の製
造方法を提供する。Accordingly, the present invention provides a method for producing a silicon nitride powder by direct nitridation from a metal silicon powder, wherein a metal powder having a particle size of 1 μm or less is used in an amount of 5% by weight or less. Provided is a method for producing silicon powder.
【００１０】以下、本発明について更に詳しく説明する
と、本発明の直接窒化法により得られる窒化ケイ素粉末
は、２０００ｋｇ／ｃｍ2の圧力で冷間ラバープレス成
形法にて成形した成形体の密度が１．９０ｇ／ｃｍ3以
上、好ましくは１．９５ｇ／ｃｍ3以上と高充填性であ
る。Hereinafter, the present invention will be described in more detail. The silicon nitride powder obtained by the direct nitriding method of the present invention has a density of 1% by a cold rubber press molding method at a pressure of 2000 kg / cm 2. .90g / cm 3 or more, preferably 1.95 g / cm 3 or more and a high filling property.
【００１１】このような高充填性窒化ケイ素粉末を得る
には、原料として粒径１μｍ以下の粒子が５重量％以
下、好ましくは２重量％以下の金属ケイ素粉末を使用す
る。粒径が１μｍ以下の微粒子が５重量％より多い金属
ケイ素粉末を使用すると、得られる窒化ケイ素粉末に針
状粒が多くなり、高充填性とならない。原料の金属ケイ
素粉末の平均粒径については特に制限はないが、上記微
粒子が上記量以下であれば、反応性の面から平均粒径は
小さい方が好ましく、また、純度はできる限り高いこと
が望ましい。In order to obtain such a highly-filled silicon nitride powder, metal silicon powder having a particle size of 1 μm or less, 5% by weight or less, preferably 2% by weight or less is used as a raw material. If metal silicon powder having a particle size of 1 μm or less is used in an amount of more than 5% by weight, the obtained silicon nitride powder will have many needle-like particles and will not have high filling properties. The average particle diameter of the raw metal silicon powder is not particularly limited, but as long as the fine particles are not more than the above amount, the average particle diameter is preferably smaller in terms of reactivity, and the purity is preferably as high as possible. desirable.
【００１２】上記金属ケイ素粉末を用いて直接窒化法に
より窒化ケイ素粉末を得る場合、窒化の反応条件は、特
に制限されないが反応温度が１３５０〜１４５０℃、反
応時間は１〜５時間とすることが好ましい。また、反応
時の雰囲気は、窒素と水素との混合ガス雰囲気下で行う
ことが好ましく、この場合混合ガスの組成比は窒素ガス
／水素ガス＝９５／５〜８０／２０容積比とすることが
良い。なお、反応時の圧力は１０〜１００ｍｍＡｑとす
ることが好ましい。反応に用いる炉としては特に制限は
ないが、一般にトンネル式のプッシャー炉や箱型炉等を
用いることができる。When a silicon nitride powder is obtained by a direct nitridation method using the metal silicon powder, the nitriding reaction conditions are not particularly limited, but the reaction temperature is 1350-1450 ° C., and the reaction time is 1-5 hours. preferable. The reaction is preferably performed in an atmosphere of a mixed gas of nitrogen and hydrogen. In this case, the composition ratio of the mixed gas is preferably nitrogen gas / hydrogen gas = 95/5 to 80/20 volume ratio. good. The pressure during the reaction is preferably 10 to 100 mmAq. The furnace used for the reaction is not particularly limited, but generally a tunnel-type pusher furnace, a box furnace, or the like can be used.
【００１３】窒化反応により得られた窒化ケイ素は通常
ジョークラッシャー等により解砕後、エアーサイクロン
ミル（ＡＣＭ）やローラーミルにより粗粉砕し、更に乾
式あるいは湿式の微粉砕機により目的の粒度まで微粉砕
する。粉砕後は一般的な化学処理を行い、水洗後、乾燥
し、窒化ケイ素粉末を得ることができる。この窒化ケイ
素粉末の平均粒径は０．５〜１μｍの範囲が好ましい。The silicon nitride obtained by the nitriding reaction is usually pulverized by a jaw crusher or the like, then coarsely pulverized by an air cyclone mill (ACM) or a roller mill, and further pulverized to a desired particle size by a dry or wet pulverizer. I do. After the pulverization, a general chemical treatment is performed, followed by washing with water and drying to obtain a silicon nitride powder. The average particle size of the silicon nitride powder is preferably in the range of 0.5 to 1 μm.
【００１４】このようにして得られた窒化ケイ素粉末
は、針状粒が極めて少なく、具体的には走査型電子顕微
鏡（ＳＥＭ）４０００倍の一視野中のアスペクト比が３
以上の針状粒の個数を３以下とすることができる。この
ため、水を媒体にしたスラリーに調製した場合、極めて
低粘度であり、具体的には後述する実施例の方法により
調製、試験したスラリーの粘度は２００ｃｐ以下とする
ことができ、また、成形体の密度が高く、具体的には２
０００ｋｇ／ｃｍ2の圧力で冷間ラバープレス成形法に
て成形した成形体の密度が１．９０ｇ／ｃｍ3以上、特
に１．９５ｇ／ｃｍ3以上とすることができる。The silicon nitride powder thus obtained has very few needle-like grains. Specifically, the scanning electron microscope (SEM) has an aspect ratio in one visual field of 4000 times that of 3 times.
The number of the needle-like particles can be set to 3 or less. For this reason, when prepared into a slurry using water as a medium, the viscosity is extremely low. Specifically, the viscosity of the slurry prepared and tested by the method of the examples described below can be 200 cp or less. High body density, specifically 2
The density of a molded product formed by a cold rubber press molding method at a pressure of 000 kg / cm 2 can be 1.90 g / cm 3 or more, particularly 1.95 g / cm 3 or more.
【００１５】[0015]
【実施例】以下、実施例と比較例を示し、本発明を具体
的に示すが、本発明は下記の実施例に制限されるもので
はない。EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.
【００１６】［実施例１］平均粒径７μｍ、１μｍ以下
の粒子が３．１重量％の金属ケイ素粉末を原料とし、１
５容量％の水素ガスを含む水素ガスと窒素ガスとの混合
ガス雰囲気下、１３８０℃で１時間保持となるようにプ
ッシャー反応炉で窒化反応を行い、窒化ケイ素粉末を得
た。これをジョークラッシャーにより解砕し、エアーサ
イクロンミルにより粗粉砕した。このようにして得られ
た窒化ケイ素粉末中の針状粒を走査型電子顕微鏡により
観察し、更に湿式アトライターで微粉砕して微粉末と
し、走査型電子顕微鏡による針状粒数の観察、成形体の
密度測定及びスラリーの粘度測定を行った。Example 1 A metal silicon powder containing 3.1% by weight of particles having an average particle diameter of 7 μm and 1 μm or less was used as a raw material.
In a mixed gas atmosphere of a hydrogen gas containing 5% by volume of hydrogen gas and a nitrogen gas, a nitriding reaction was performed in a pusher reaction furnace at 1380 ° C. for 1 hour to obtain silicon nitride powder. This was crushed by a jaw crusher and coarsely crushed by an air cyclone mill. The needle-like particles in the silicon nitride powder thus obtained are observed with a scanning electron microscope, and further finely pulverized into a fine powder with a wet attritor, and the number of needle-like particles is observed and formed with a scanning electron microscope. The density of the body and the viscosity of the slurry were measured.
【００１７】なお、成形密度は２０００ｋｇ／ｃｍ2加
重で冷間ラバープレス成形して得られる成形体の寸法密
度を測定した。The compact density was measured by measuring the dimensional density of a compact obtained by cold rubber press molding under a load of 2000 kg / cm 2 .
【００１８】また、スラリーの粘度は、１リットルのポ
リエチレン製ポットに対し１５ｍｍ径のナイロン被覆Ｆ
ｅボールを１００個用い、粉末２５０ｇに対し水１７５
ｇを使用し、分散剤（東亜合成化学製Ａ−３０ＳＬ）を
粉末外掛で１％添加し、１０６ｒｐｍで１５時間混合し
てスラリーを調製し、この調製したスラリーの粘度を東
京精機製Ｂ型粘度計にて測定した（ローターＮｏ．３で
６０ｒｐｍ×３０秒）。The viscosity of the slurry is as follows.
Using 100 e-balls, 250 g of powder and 175 of water
g, a dispersant (A-30SL, manufactured by Toa Gosei Chemical Co., Ltd.) is added in an amount of 1% by powder coating, and the mixture is mixed at 106 rpm for 15 hours to prepare a slurry. (60 rpm × 30 seconds with rotor No. 3).
【００１９】［実施例２］原料として平均粒径１０μ
ｍ、１μｍ以下の粒子が１．３重量％の金属ケイ素粉末
を使用したほかは、実施例１と同様の方法により窒化ケ
イ素粉末を得、同様に顕微鏡による針状粒数観察、成形
密度測定、スラリー粘度測定を行った。[Example 2] As a raw material, an average particle diameter was 10 µm.
m, 1 μm or less particles of 1.3% by weight of metal silicon powder were used, except that silicon nitride powder was obtained in the same manner as in Example 1, and the number of needle-like particles was observed with a microscope, the molding density was measured, A slurry viscosity measurement was performed.
【００２０】［比較例］原料として平均粒径４μｍ、１
μｍ以下の粒子が１１．２重量％の金属ケイ素粉末を使
用したほかは、実施例１と同様の方法により窒化ケイ素
粉末を得、同様に顕微鏡による針状粒数観察、成形密度
測定、スラリー粘度測定を行った。以上の結果を表１に
示す。COMPARATIVE EXAMPLE The raw material had an average particle size of 4 μm,
A silicon nitride powder was obtained in the same manner as in Example 1 except that a metal silicon powder having a particle size of 1 μm or less of 11.2% by weight was used. Similarly, observation of the number of needle-like particles by a microscope, measurement of molding density, and slurry viscosity A measurement was made. Table 1 shows the above results.
【００２１】[0021]
【表１】 ＊ レーザー回折法による ＊＊ＳＥＭ ４０００倍１視野中のウィスカー（アスペ
クト比≧３）の個数[Table 1] * The number of whiskers (aspect ratio ≧ 3) in one field of view of SEM 4000 times by laser diffraction method **
【００２２】[0022]
【発明の効果】本発明によれば、針状粒が非常に少な
く、スラリー化の際に高濃度低粘度化が達成され、成形
体の密度を高くすることができ、このため、焼結体の強
度や寸法精度の点で有利な高充填性窒化ケイ素粉末を確
実に製造することができる。According to the present invention, the number of needle-like particles is very small, high density and low viscosity can be achieved during slurrying, and the density of the compact can be increased. Thus, a highly-fillable silicon nitride powder that is advantageous in terms of strength and dimensional accuracy can be reliably produced.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 桑原 治由 群馬県安中市磯部２丁目13番１号 信越 化学工業株式会社 精密機能材料研究所 内 (72)発明者 進藤 敏彦 群馬県安中市磯部２丁目13番１号 信越 化学工業株式会社 精密機能材料研究所 内 (56)参考文献 特開 平１−261435（ＪＰ，Ａ) 特開 平５−58606（ＪＰ，Ａ) 特開 平５−221617（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) C01B 21/068 C04B 35/626 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Haruyoshi Kuwahara 2-13-1 Isobe, Annaka-shi, Gunma Shin-Etsu Chemical Co., Ltd.Precision Functional Materials Laboratory (72) Inventor Toshihiko Shindo Annaka-shi, Gunma 2-13-1 Isobe Shin-Etsu Chemical Co., Ltd. Precision Functional Materials Laboratory (56) References JP-A 1-261435 (JP, A) JP-A 5-58606 (JP, A) JP-A 5- 221617 (JP, A) (58) Field surveyed (Int. Cl. 6 , DB name) C01B 21/068 C04B 35/626
Claims (1)
化ケイ素粉末を製造する方法において、１μｍ以下の粒
子が５重量％以下の金属ケイ素粉末を用いることを特徴
とする高充填性窒化ケイ素粉末の製造方法。1. A method for producing silicon nitride powder directly from metal silicon powder by a nitriding method, wherein a metal silicon powder having a particle size of 1 μm or less and 5% by weight or less is used. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5036163A JP2946990B2 (en) | 1993-02-01 | 1993-02-01 | Method for producing highly-fillable silicon nitride powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5036163A JP2946990B2 (en) | 1993-02-01 | 1993-02-01 | Method for producing highly-fillable silicon nitride powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06227804A JPH06227804A (en) | 1994-08-16 |
| JP2946990B2 true JP2946990B2 (en) | 1999-09-13 |
Family
ID=12462103
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|---|---|---|---|
| JP5036163A Expired - Fee Related JP2946990B2 (en) | 1993-02-01 | 1993-02-01 | Method for producing highly-fillable silicon nitride powder |
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| Country | Link |
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|---|---|
| JPH06227804A (en) | 1994-08-16 |
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