JPH05238710A - Silicon nitride powder - Google Patents
Silicon nitride powderInfo
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- JPH05238710A JPH05238710A JP4076302A JP7630292A JPH05238710A JP H05238710 A JPH05238710 A JP H05238710A JP 4076302 A JP4076302 A JP 4076302A JP 7630292 A JP7630292 A JP 7630292A JP H05238710 A JPH05238710 A JP H05238710A
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- Prior art keywords
- silicon nitride
- nitride powder
- powder
- silicon
- solvent
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、窒化ケイ素粉末、更に
詳しくは、高強度で強度ばらつき、寸法ばらつきの小さ
い信頼性の高い窒化ケイ素焼結体を得るのに必要となる
高密度かつ粉末の充填が均質な成形体を与える窒化ケイ
素粉末に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon nitride powder, and more particularly to a silicon nitride powder having a high density and a high density, which is required for obtaining a highly reliable silicon nitride sintered body having small strength variations and small dimensional variations. It relates to silicon nitride powders which give compacts with homogeneous filling.
【０００２】[0002]
【従来の技術】窒化ケイ素焼結体は、通常、窒化ケイ素
粉末と主にY2O3，Al2O3 等の焼結助剤粉末とをトリクロ
ルエタン等の溶媒中でボールミル等により混合してスラ
リー化し、これに成形用バインダーを添加混合した後、
直接、鋳込みや加圧鋳込み法により成形するか、もしく
は、スラリーを乾燥してプレス成形あるいは射出成形に
より成形体を作り、この成形体を必要に応じて脱脂し、
続いて焼成して作製される。2. Description of the Related Art A silicon nitride sintered body is usually prepared by mixing silicon nitride powder and a sintering aid powder such as Y 2 O 3 or Al 2 O 3 in a solvent such as trichloroethane by a ball mill or the like. To form a slurry, and after adding and mixing the molding binder,
Directly molding by casting or pressure casting method, or by drying the slurry to make a molded body by press molding or injection molding, degreasing this molded body as necessary,
Subsequently, it is fired to be manufactured.
【０００３】これらの方法において、焼結助剤の種類、
添加量および焼結条件が同じであれば、焼結体の物性、
例えば強度や寸法精度および該物性のばらつきは、主に
成形体の密度や充填構造により影響を受ける。従来、成
形体の密度を増加させるために、原料となる窒化ケイ素
粉末に関して、例えば特開平３−１５９９０７に示され
るように粒径や粒度分布の制御が行われてきた。しか
し、一方で焼結体物性向上の点から原料に用いられる窒
化ケイ素粉末は微粒化される傾向にある（例えば、島村
常夫ら，粉末と工業，Ｐ３６，VOL.２１，Ｎｏ．８（１
９８９）．）In these methods, the type of sintering aid,
If the addition amount and sintering conditions are the same, the physical properties of the sintered body,
For example, strength, dimensional accuracy, and variations in the physical properties are mainly affected by the density of the molded body and the filling structure. Conventionally, in order to increase the density of a molded body, the particle size and particle size distribution of silicon nitride powder as a raw material have been controlled as shown in, for example, JP-A-3-159907. However, on the other hand, from the viewpoint of improving the physical properties of the sintered body, the silicon nitride powder used as a raw material tends to be atomized (for example, Tsuneo Shimamura et al., Powder and Industry, P36, VOL. 21, No. 8 (1
989). )
【０００４】[0004]
【発明が解決しようとする課題】ところが、微粒な窒化
ケイ素粉末を原料に用いた場合、得られる成形体の密度
が低く、成形体内部の密度斑やポアあるいは巣が発生す
るという問題があった。However, when finely divided silicon nitride powder is used as a raw material, there is a problem that the density of the obtained molded product is low and density unevenness, pores or cavities are generated inside the molded product. ..
【０００５】そこで、本発明者らは、上記の問題点に鑑
み鋭意検討した結果、窒化ケイ素粉末の表面特性によ
り、混合工程における窒化ケイ素粉末の溶媒中での分散
性が大きく変化し、窒化ケイ素粉末の混合溶媒中での分
散状態が成形体の粉末充填構造に影響を与えることを見
出し本発明に至った。The inventors of the present invention have made extensive studies in view of the above problems, and as a result, the surface characteristics of the silicon nitride powder significantly change the dispersibility of the silicon nitride powder in the solvent during the mixing step. The inventors have found that the state of dispersion of powder in a mixed solvent affects the powder filling structure of a molded body, leading to the present invention.
【０００６】従って本発明は、高密度で粉末の充填が均
質な成形体を与えることができ、高強度で強度ばらつ
き、寸法ばらつきの小さい信頼性の高い窒化ケイ素焼結
体を形成することができる窒化ケイ素粉末を提供するこ
とを目的としている。Therefore, according to the present invention, it is possible to provide a compact having a high density and a uniform powder filling, and it is possible to form a highly reliable silicon nitride sintered body having a high strength, a small strength variation and a small dimension variation. The purpose is to provide a silicon nitride powder.
【０００７】[0007]
【課題を解決するための手段】すなわち、本発明はＢ．
Ｅ．Ｔ．表面積当りの表面酸性基量が 0.2μｅｑ／ｍ2
以上であることを特徴とする窒化ケイ素粉末である。That is, the present invention relates to B.
E. T. The amount of surface acidic groups per surface area is 0.2μeq / m 2
The above is a silicon nitride powder characterized by the above.
【０００８】本発明におけるＢ．Ｅ．Ｔ．表面積当りの
表面酸性基量が 0.2μｅｑ／ｍ2 以上、好ましくは 0.5
μｅｑ／ｍ2 以上の窒化ケイ素粉末を用いることにより
溶媒中での分散性が大幅に向上し、均質かつ高密度な成
形体が得られる。一方、Ｂ．Ｅ．Ｔ．表面積当りの表面
酸性基量が 0.2μｅｑ／ｍ2 未満の窒化ケイ素粉末は、
溶媒中での分散状態が著しく悪化し凝集が顕著となる。B. in the present invention E. T. The amount of surface acidic groups per surface area is 0.2 μeq / m 2 or more, preferably 0.5
By using the silicon nitride powder of μeq / m 2 or more, the dispersibility in the solvent is greatly improved, and a homogeneous and high-density molded product can be obtained. On the other hand, B. E. T. A silicon nitride powder having an amount of surface acidic groups per surface area of less than 0.2 μeq / m 2 is
The state of dispersion in the solvent is markedly deteriorated and the aggregation is remarkable.
【０００９】さらに、焼結体の微細組織を制御するため
には、平均一次粒子径 0.5μｍ以下の微細な窒化ケイ素
粉末を用いることが望ましい。このような微細粉末の場
合、粉末間の凝集力が大きいため、溶媒中で十分に分散
させるためには、Ｂ．Ｅ．Ｔ．表面積当りの表面酸性基
量が 1.0μｅｑ／ｍ2 以上であることが好ましい。Further, in order to control the fine structure of the sintered body, it is desirable to use fine silicon nitride powder having an average primary particle diameter of 0.5 μm or less. In the case of such a fine powder, since the cohesive force between the powders is large, it is necessary to use B. E. T. The amount of surface acidic groups per surface area is preferably 1.0 μeq / m 2 or more.
【００１０】混合溶媒としては特に限定されないが、窒
化ケイ素粉末のＢ．Ｅ．Ｔ．表面積当りの表面酸性基量
を上記範囲に制御することによって、アルコール，水等
の極性溶媒への分散性が著しく改善され、溶媒の誘電率
が大きくなる程、この傾向は顕著となる。The mixed solvent is not particularly limited, but the B.V. E. T. By controlling the amount of surface acidic groups per surface area within the above range, dispersibility in polar solvents such as alcohol and water is remarkably improved, and this tendency becomes more remarkable as the dielectric constant of the solvent increases.
【００１１】溶媒として水は誘電率が大きくかつ安価
で、可燃性有機溶媒のように防爆等の安全対策を必要と
しないため工業上非常に優れるが、窒化ケイ素の水に対
する安定性が問題となる。これに対しては、Ｘ線光電子
分光［ＸＰＳ］より求められる表面ケイ素［Si］のうち
SiO2に帰属されるケイ素［ Si*］の割合が原子比［ Si*
／Si］で0.07以上の窒化ケイ素粉末を用いることによ
り、水中で安定して混合することができ、さらにＢ．
Ｅ．Ｔ．表面積当りの表面酸性基量を上記範囲に制御す
ることで分散性を高めることができる。該［ Si*／Si］
比が0.07未満の窒化ケイ素粉末を用いた場合、水によっ
て窒化ケイ素が分解されるので好ましくない。Water as a solvent has a large permittivity and is inexpensive, and does not require safety measures such as explosion proof unlike a flammable organic solvent, but is industrially excellent, but the stability of silicon nitride against water poses a problem. .. On the other hand, of the surface silicon [Si] obtained by X-ray photoelectron spectroscopy [XPS],
The ratio of silicon [Si * ] attributed to SiO 2 is the atomic ratio [Si *
/ Si] by using a silicon nitride powder having a value of 0.07 or more, stable mixing in water is possible.
E. T. Dispersibility can be enhanced by controlling the amount of surface acidic groups per surface area within the above range. The [Si * / Si]
The use of a silicon nitride powder having a ratio of less than 0.07 is not preferable because water decomposes silicon nitride.
【００１２】本発明におけるＢ．Ｅ．Ｔ．表面積当りの
表面酸性基量を 0.2μｅｑ／ｍ2 以上の窒化ケイ素粉末
は、イミド分解法、直接窒化法等の方法で合成された窒
化ケイ素粉末を１体積％以上の酸素を含む雰囲気あるい
は 0.5体積％以上の水蒸気雰囲気下で加熱処理すること
によって得ることができる。処理温度は酸素雰囲気の場
合500 〜850 ℃、水蒸気雰囲気の場合は200 〜800 ℃が
好ましい。B. in the present invention E. T. Silicon nitride powder with a surface acid group content of 0.2 μeq / m 2 or more per surface area is silicon nitride powder synthesized by a method such as imide decomposition method or direct nitriding method in an atmosphere containing 1 volume% or more oxygen or 0.5 volume. It can be obtained by heat treatment in a steam atmosphere of not less than 100%. The treatment temperature is preferably 500 to 850 ° C. in the oxygen atmosphere and 200 to 800 ° C. in the water vapor atmosphere.
【００１３】上記熱処理により窒化ケイ素表面にはSiO2
被膜が形成されるため、処理時間を制御することによっ
て、窒化ケイ素表面の［ Si*／Si］比を0.07以上にする
ことができる。By the above heat treatment, SiO 2 is formed on the surface of silicon nitride.
Since the film is formed, the [Si * / Si] ratio of the silicon nitride surface can be 0.07 or more by controlling the treatment time.
【００１４】窒化ケイ素粉末と焼結助剤粉末とを混合す
る際、各種溶媒を用いた湿式混合が一般に行われてい
る。この際、主に、焼結助剤粉末の分散性を向上させる
ために界面活性剤や解膠剤が添加される。しかし、焼結
助剤粉末の溶媒に対する分散性をいくら向上させたとし
ても、主成分である窒化ケイ素粉末の溶媒中での分散性
が不十分であれば、窒化ケイ素粉末の凝集が生じ、特に
鋳込み成形や加圧鋳込成形のような湿式成形において
は、該窒化ケイ素粉末の凝集が成形体の密度斑やポアや
巣の原因となる。When the silicon nitride powder and the sintering aid powder are mixed, wet mixing using various solvents is generally performed. At this time, a surfactant or a deflocculant is mainly added to improve the dispersibility of the sintering aid powder. However, no matter how much the dispersibility of the sintering aid powder in the solvent is improved, if the dispersibility of the silicon nitride powder as the main component in the solvent is insufficient, agglomeration of the silicon nitride powder occurs, particularly In wet molding such as cast molding and pressure cast molding, the agglomeration of the silicon nitride powder causes density unevenness, pores and cavities of the molded body.
【００１５】また、スプレードライヤー等による乾燥・
造粒を行った場合にも造粒中にポアや粉末の不均一構造
が生じる。さらに上記湿式成形や乾燥において、粉末間
の凝集力が大きい程、脱溶媒に伴う粉末の接触が不均一
となり疎な充填構造となり易く、不均質で低密度な成形
体となってしまう。Further, drying by a spray dryer or the like
Even when granulation is performed, pores and a non-uniform structure of powder are generated during granulation. Further, in the above-mentioned wet molding or drying, the larger the cohesive force between the powders, the more uneven the contact of the powders due to the solvent removal and the sparse packing structure is likely to occur, resulting in a non-uniform and low-density molded body.
【００１６】溶媒中において窒化ケイ素粉末に撹拌等に
より剪断力を与えると、弱い凝集体は一時的に解膠され
るが、すぐに再凝集が生じるため、解膠、凝集の平衡状
態により分散性が決まる。When a shearing force is applied to the silicon nitride powder in a solvent by stirring or the like, weak aggregates are temporarily deflocculated, but reaggregation occurs immediately. Therefore, the equilibrium state of deflocculation and aggregation causes dispersibility. Is decided.
【００１７】極性溶媒においては、粉末表面電荷に起因
する静電反発力がこの再凝集を抑制することで分散性に
寄与しており、この静電反発力を有効に発現させるため
には、先ず窒化ケイ素粉末粒子表面が溶媒で覆われるこ
とが必要条件となる。すなわち窒化ケイ素粉末とこれら
溶媒との濡れ性が悪いと窒化ケイ素粉末の分散性が悪
く、しかも溶媒に浸漬する以前に凝集しているものへ
は、凝集体を形成している粉末粒子間に溶媒が浸透せ
ず、剪断力を与えても容易に解膠することが困難となる
と考えられる。In the polar solvent, the electrostatic repulsion force due to the powder surface charge contributes to the dispersibility by suppressing this re-aggregation. In order to effectively develop this electrostatic repulsion force, It is a necessary condition that the surface of the silicon nitride powder particles is covered with a solvent. That is, if the wettability between the silicon nitride powder and these solvents is poor, the dispersibility of the silicon nitride powder is poor, and if the particles agglomerate before being immersed in the solvent, the solvent between the powder particles forming the agglomerates is used. It is thought that it will not penetrate and that it will be difficult to deflocculate even if a shear force is applied.
【００１８】これに対して本発明による窒化ケイ素粉末
は、極性溶媒との親和力が強い表面酸性基量を粉末表面
全体を溶媒で濡らすのに必要な量存在させているため、
溶媒との濡れ性が飛躍的に向上し、溶媒中での分散性を
著しく改善することができる。On the other hand, in the silicon nitride powder according to the present invention, the amount of surface acidic groups having a strong affinity for the polar solvent is present in an amount necessary for wetting the entire powder surface with the solvent.
The wettability with the solvent is remarkably improved, and the dispersibility in the solvent can be remarkably improved.
【００１９】また、極性溶媒に水を用いた場合には、窒
化ケイ素の水による分解が生じるが、本発明における上
記［ Si*／Si］比が0.07以上の窒化ケイ素粉末を用いた
場合、窒化ケイ素粉末の表面に存在するSiO2被膜により
水による分解を防止することができる。When water is used as the polar solvent, the silicon nitride is decomposed by water. However, when the silicon nitride powder having the above [Si * / Si] ratio of 0.07 or more is used, The SiO 2 coating present on the surface of the silicon powder can prevent decomposition by water.
【００２０】尚、本発明におけるＢ．Ｅ．Ｔ．表面積当
りの表面酸性基量および［ Si*／Si］比は以下の方法で
求めた。The B. E. T. The amount of surface acidic groups per surface area and the [Si * / Si] ratio were determined by the following methods.
【００２１】〈Ｂ．Ｅ．Ｔ．表面積当りの表面酸性基
量〉窒化ケイ素粉末を 110℃で１２時間真空乾燥した
後、10g を秤量し、これをポリプロピレン製フラスコに
写し、1/100 規定NaOH水溶液を100ml 加えて、25℃で４
時間振とうした。これを遠心分離により、粉末を沈降さ
せ、上澄み液を25ml秤量し、フェノールフタレインを指
示薬として1/100 規定HCl 水溶液で滴定した。同様に窒
化ケイ素粉末を加えない系で空試験を行い、空試験の滴
定値を規準として次式によりＢ．Ｅ．Ｔ．表面積当りの
酸性基量を求めた。尚、各試料について５回測定を行い
その平均を測定値とした。<B. E. T. Amount of surface acidic group per surface area> After vacuum-drying silicon nitride powder at 110 ° C for 12 hours, weigh 10 g, transfer this to a polypropylene flask, add 100 ml of 1/100 normal NaOH aqueous solution, and add 4 at 25 ° C.
Shake for time. The powder was settled by centrifugation, 25 ml of the supernatant was weighed, and titrated with a 1/100 normal HCl aqueous solution using phenolphthalein as an indicator. Similarly, a blank test was conducted in a system in which no silicon nitride powder was added, and B. E. T. The amount of acidic groups per surface area was determined. Each sample was measured 5 times and the average thereof was used as the measured value.
【００２２】 Ｘ：HCl 水溶液の滴定量 （ml) Ｂ：空試験の滴定量 （ml) Ｋ：HCl 水溶液の規定度 （Ｎ） Ｗ：窒化ケイ素粉末の重量 （ｇ） Ｓ：窒化ケイ素粉末のＢ．Ｅ．Ｔ．表面積 (m2/g)[0022] X: Titrate of HCl aqueous solution (ml) B: Titration of blank test (ml) K: Normality of HCl aqueous solution (N) W: Weight of silicon nitride powder (g) S: B. of silicon nitride powder E. T. Surface area (m 2 / g)
【００２３】〈［ Si*／Si］比〉窒化ケイ素粉末を 110
℃で１２時間真空乾燥した後、ＸＰＳの予備チャンバー
で、室温，10-4〜10-5torrの真空中で１〜８時間脱ガス
処理を行い、分析チャンバーに試料を導入後、バックグ
ラウンドの真空が10-10torr オーダーになってから測定
を行った。表面のトータルケイ素［Si］はSi2pピークよ
り求め、さらにSi2pの波形分離を行い、103.4eV ± 0.5
eVのピークをSiO2に帰属されるケイ素［ Si*］として
［ Si*／Si］比を原子比で求めた。測定にはPerkin Elm
er社 ESCA5400MC を用いＸ線源は単色化したＡｌＫαを
用いた。<[Si * / Si] ratio> 110% silicon nitride powder
After vacuum-drying at 12 ° C for 12 hours, degassing treatment is performed in a preliminary chamber of XPS at room temperature under vacuum of 10 -4 to 10 -5 torr for 1 to 8 hours. The measurement was performed after the vacuum reached the 10 -10 torr order. The total silicon [Si] on the surface was obtained from the Si 2 p peak, and the waveform of Si 2 p was further separated to obtain 103.4 eV ± 0.5
The [Si * / Si] ratio was determined by the atomic ratio, with the eV peak as silicon [Si * ] assigned to SiO 2 . Perkin Elm for measurement
The ESCA5400MC manufactured by er Co., Ltd. was used, and the monochromatic AlKα was used as the X-ray source.
【００２４】以下、本発明の実施例について述べるが、
本発明はこれに限定されるものではない。Examples of the present invention will be described below.
The present invention is not limited to this.
【００２５】[0025]
【実施例１】α結晶化率96.0％、平均一次粒子径 0.2μ
ｍの窒化ケイ素粉末を10体積％の水蒸気を含むＮ2 雰囲
気または大気中で熱処理を行い表１に示す性量を有する
窒化ケイ素粉末を作製した。Example 1 α crystallization rate 96.0%, average primary particle size 0.2μ
The silicon nitride powder of m was heat-treated in an N 2 atmosphere containing 10 vol% of water vapor or in the air to produce a silicon nitride powder having the properties shown in Table 1.
【００２６】次にこれらの窒化ケイ素粉末92重量部に焼
結助剤として平均一次粒子径0.25μｍのY2O3５重量部と
平均一次粒子径0.15μｍのAl2O3 ３重量部を添加し、粉
末総量に対して70重量％のエタノールを加えナイロン製
ボールミルにより100rpmで４８時間混合した後、バイン
ダーを粉末総量に対して 0.5重量％添加し、続いて１時
間混合した。得られたスラリーを真空脱泡後、多孔型へ
30kg/cm2の圧力で加圧鋳込成形を行い10cm×10cm×5.5m
mtの成形体を得た。この成形体を 100℃で１２時間乾燥
後、図１に示した個所の密度をγ線微小部密度測定装置
により測定した。測定結果および成形前のスラリーの粘
度を表２に示す。また、成形体の重量および寸法より算
出したバルク密度も同表に示す。Next, to 92 parts by weight of these silicon nitride powders, 5 parts by weight of Y 2 O 3 having an average primary particle diameter of 0.25 μm and 3 parts by weight of Al 2 O 3 having an average primary particle diameter of 0.15 μm were added as sintering aids. Then, 70% by weight of ethanol was added to the total amount of the powder and mixed by a nylon ball mill at 100 rpm for 48 hours, and then 0.5% by weight of the binder was added to the total amount of the powder, followed by mixing for 1 hour. Vacuum degassing of the obtained slurry, and then to porous type
Performs pressure casting at a pressure of 30 kg / cm 2 and measures 10 cm x 10 cm x 5.5 m.
A molded body of m t was obtained. After the molded body was dried at 100 ° C. for 12 hours, the density of the portion shown in FIG. 1 was measured by a γ-ray minute portion density measuring device. Table 2 shows the measurement results and the viscosity of the slurry before molding. The bulk density calculated from the weight and size of the molded body is also shown in the table.
【００２７】乾燥後の成形体を切断、研削により8mm ×
48mm×5.5mmtの試験片１６本に加工した。この試験片を
750℃で３時間脱脂し、Ｎ2 雰囲気下、1720℃で５時間
焼成した後、1720℃，1000気圧のＮ2 中で３時間ＨＩＰ
処理した。8 mm × by cutting and grinding the dried molded body
It processed into 16 test pieces of 48 mm x 5.5 mm t . This test piece
After degreasing at 750 ° C for 3 hours and firing at 1720 ° C for 5 hours in N 2 atmosphere, HIP in N 2 at 1720 ° C and 1000 atm for 3 hours
Processed.
【００２８】得られた焼結体の密度をアルキメデス法に
より求め、厚みを測定した後、ＪＩＳＲ1601に準拠した
抗折試験片に加工し四点曲げ試験を行った。結果を表２
に示す。The density of the obtained sintered body was determined by the Archimedes method, the thickness was measured, and then a bending test piece conforming to JIS R1601 was processed and a four-point bending test was performed. The results are shown in Table 2.
Shown in.
【００２９】表２の結果より、比較例（Ａ，Ｂ）に対し
て本発明の窒化ケイ素粉末（Ｃ〜Ｉ）を用いた場合、エ
タノール中での分散性向上に伴うスラリーの粘度の低下
が認められ、高密度で密度ばらつきの小さな成形体が得
られる。焼結体の平均強度，ワイブル係数，寸法精度が
大幅に向上することがわかる。From the results shown in Table 2, when the silicon nitride powders (C to I) of the present invention were used for Comparative Examples (A, B), the viscosity of the slurry was lowered due to the improvement of the dispersibility in ethanol. A molded product having a high density and a small variation in density is obtained. It can be seen that the average strength, Weibull coefficient, and dimensional accuracy of the sintered body are greatly improved.
【００３０】[0030]
【実施例２】表１の窒化ケイ素粉末Ａ〜Ｉについて、溶
媒に水を用いて下記手順で実施例１と同様の成形体を作
製した。Example 2 With respect to the silicon nitride powders A to I in Table 1, water was used as a solvent, and a molded body similar to that of Example 1 was prepared by the following procedure.
【００３１】窒化ケイ素粉末92重量部、実施例１で用い
たY2O3５重量部およびAl2O3 ３重量部を準備し、先ず窒
化ケイ素粉末にアンモニアでpH 9.5に調整したイオン交
換水を粉末総量に対して48重量％加え、ナイロン製ボー
ルミルにより100rpmで１２時間混合し、続いてこれにY2
O3，Al2O3 を添加して１２時間混合した後、粉末総量に
対して 0.5重量％のバインダーを加えて、さらに１時間
混合した。得られたスラリーのpHを測定したところ、窒
化ケイ素粉末Ａ，Ｂ，Ｅ及びＧのスラリーは各々pH 11.
2 ，pH 10.7 ，pH 11.0 ，pH 10.8 にpH値が増加してお
り、水による窒化ケイ素粉末の分解が生じていることが
認められた。92 parts by weight of silicon nitride powder, 5 parts by weight of Y 2 O 3 and 3 parts by weight of Al 2 O 3 used in Example 1 were prepared. First, silicon nitride powder was adjusted to pH 9.5 with ammonia and deionized water was prepared. 48% by weight based on the total amount of powder, and mixed by a nylon ball mill at 100 rpm for 12 hours, followed by Y 2
After O 3 and Al 2 O 3 were added and mixed for 12 hours, 0.5% by weight of the binder was added to the total amount of the powder, and the mixture was further mixed for 1 hour. When the pH of the obtained slurry was measured, the pH of the slurries of silicon nitride powders A, B, E and G was 11.
2, the pH values increased to pH 10.7, pH 11.0, and pH 10.8, and it was confirmed that the decomposition of the silicon nitride powder by water occurred.
【００３２】このスラリーの真空脱泡後、実施例１と同
様にして成形体、焼結体を作製し、それらの成形体およ
び焼結体の特性を測定した。結果を表３に示す。After degassing the slurry in a vacuum, molded bodies and sintered bodies were prepared in the same manner as in Example 1, and the characteristics of these molded bodies and sintered bodies were measured. The results are shown in Table 3.
【００３３】表３より、実施例１の結果（表２）と同様
に比較例（Ａ，Ｂ）に対して本発明の窒化ケイ素粉末
（Ｃ〜Ｉ）を用いた場合、高密度から密度ばらつきの小
さい成形体が得られ、焼結体特性も向上することがわか
る。From Table 3, when the silicon nitride powders (C to I) of the present invention were used for Comparative Examples (A, B) as in the case of the results of Example 1 (Table 2), variations in density from high density were observed. It can be seen that a compact having a small size is obtained and the characteristics of the sintered body are improved.
【００３４】また、［ Si*／Si］比が0.07未満の窒化ケ
イ素粉末Ａ，Ｂ，Ｅ，Ｇにおいては、水による分解が生
じ、溶媒にエタノールを用いた場合（表２）に比べて成
形体および焼結体特性が低下しているが、［ Si*／Si］
比が0.07以上のＣ，Ｄ，Ｆ，Ｈ，Ｉにおいては、水によ
る分解もなく、エタノール溶媒に比べさらに成形体およ
び焼結体の特性が向上した。Further, in the silicon nitride powders A, B, E and G having a [Si * / Si] ratio of less than 0.07, decomposition by water occurs, and molding is performed as compared with the case where ethanol is used as a solvent (Table 2). Properties of sintered body and sintered body are deteriorated, but [Si * / Si]
With C, D, F, H, and I having a ratio of 0.07 or more, there was no decomposition by water, and the characteristics of the molded body and the sintered body were further improved as compared with the ethanol solvent.
【００３５】[0035]
【表１】 [Table 1]
【００３６】[0036]
【表２】 [Table 2]
【００３７】[0037]
【表３】 [Table 3]
【００３８】[0038]
【発明の効果】以上述べたように、本発明のＢ，Ｅ，
Ｔ，表面積当りの表面酸性基量を増加させた窒化ケイ素
粉末を用いることにより、混合溶媒中での分散性が飛躍
的に向上し、高密度かつ均質な成形体を得ることがで
き、高強度で強度ばらつき、寸法ばらつきの小さい信頼
性の高い窒化ケイ素焼結体を容易に作製することができ
る。As described above, according to the present invention, B, E,
By using a silicon nitride powder having an increased amount of surface acidic groups per T and surface area, the dispersibility in a mixed solvent is dramatically improved, and a high-density and homogeneous molded product can be obtained, which has high strength. Thus, it is possible to easily manufacture a highly reliable silicon nitride sintered body with little variation in strength and dimension.
【００３９】また、Ｂ，Ｅ，Ｔ，表面積当りの表面酸性
基量の増加に加えＸＰＳより求められる表面ケイ素［S
i］のうち、SiO2に帰属されるケイ素［ Si*］の割合［
Si*／Si］比を増加させた窒化ケイ素粉末を用いること
により、水を溶媒に使用できるため、さらに高密度かつ
均質な成形体を作製でき、さらに特性の優れた窒化ケイ
素焼結体を安価に得ることができる。In addition to the increase in the amount of surface acidic groups per B, E, T and surface area, the surface silicon [S
of [i], the proportion of silicon [Si * ] that is assigned to SiO 2 [
By using silicon nitride powder with an increased Si * / Si] ratio, water can be used as a solvent, so a denser and more homogeneous compact can be produced, and a silicon nitride sintered body with superior characteristics can be obtained at a low cost. Can be obtained.
【図１】成形体の密度測定個所の説明図。FIG. 1 is an explanatory view of a density measurement portion of a molded body.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成４年１０月１４日[Submission date] October 14, 1992
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】請求項３[Name of item to be corrected] Claim 3
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
Claims (4)
が 0.2μｅｑ／ｍ2以上であることを特徴とする窒化ケ
イ素粉末。1. B. E. T. A silicon nitride powder having a surface acidic group content of 0.2 μeq / m 2 or more per surface area.
Ｅ．Ｔ．表面積当りの表面酸性基量が 1.0μｅｑ／ｍ2
以上であることを特徴とする請求項１記載の窒化ケイ素
粉末。2. When the average primary particle diameter is 0.5 μm or less, B.
E. T. The amount of surface acidic groups per surface area is 1.0 μeq / m 2
It is above, The silicon nitride powder of Claim 1 characterized by the above-mentioned.
る表面ケイ素［Si］のうち、SiO2に帰属されるケイ素
［ Si*］の割合が原子比［ Si*／Si］で0.01以上である
ことを特徴とする請求項１記載の窒化ケイ素粉末。3. The ratio of silicon [Si * ] belonging to SiO 2 in the surface silicon [Si] determined by X-ray photopower spectroscopy [XPS] is 0.01 or more in atomic ratio [Si * / Si]. The silicon nitride powder according to claim 1, wherein the silicon nitride powder is present.
る表面ケイ素［Si］のうち、SiO2に帰属されるケイ素
［ Si*］の割合が原子比［ Si*／Si］で0.07以上である
ことを特徴とする請求項２記載の窒化ケイ素粉末。4. The ratio of silicon [Si * ] belonging to SiO 2 in the surface silicon [Si] determined by X-ray photoelectron spectroscopy [XPS] is 0.07 or more in terms of atomic ratio [Si * / Si]. The silicon nitride powder according to claim 2, characterized in that
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4076302A JPH05238710A (en) | 1992-02-26 | 1992-02-26 | Silicon nitride powder |
| DE69309515T DE69309515T2 (en) | 1992-01-24 | 1993-01-22 | Silicon nitride powder and process for its production |
| EP93300485A EP0554020B1 (en) | 1992-01-24 | 1993-01-22 | Silicon nitride powder and method for its manufacture |
| US08/403,122 US5538927A (en) | 1992-01-24 | 1995-03-13 | Silicon nitride powder and its manufacturing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4076302A JPH05238710A (en) | 1992-02-26 | 1992-02-26 | Silicon nitride powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05238710A true JPH05238710A (en) | 1993-09-17 |
Family
ID=13601580
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4076302A Pending JPH05238710A (en) | 1992-01-24 | 1992-02-26 | Silicon nitride powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05238710A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001253777A (en) * | 2000-03-13 | 2001-09-18 | Ibiden Co Ltd | Ceramic substrate |
| JP2003243495A (en) * | 2002-10-30 | 2003-08-29 | Ibiden Co Ltd | Ceramic substrate |
| US6825555B2 (en) | 2000-06-16 | 2004-11-30 | Ibiden Co., Ltd. | Hot plate |
-
1992
- 1992-02-26 JP JP4076302A patent/JPH05238710A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001253777A (en) * | 2000-03-13 | 2001-09-18 | Ibiden Co Ltd | Ceramic substrate |
| US6825555B2 (en) | 2000-06-16 | 2004-11-30 | Ibiden Co., Ltd. | Hot plate |
| JP2003243495A (en) * | 2002-10-30 | 2003-08-29 | Ibiden Co Ltd | Ceramic substrate |
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