JP2003034578A - Silicon nitride-based composite sintered body and method for producing the same - Google Patents
Silicon nitride-based composite sintered body and method for producing the sameInfo
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- JP2003034578A JP2003034578A JP2001222814A JP2001222814A JP2003034578A JP 2003034578 A JP2003034578 A JP 2003034578A JP 2001222814 A JP2001222814 A JP 2001222814A JP 2001222814 A JP2001222814 A JP 2001222814A JP 2003034578 A JP2003034578 A JP 2003034578A
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- silicon nitride
- sintered body
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、各種機構部材や切
削工具・摺動部材等に使用される高耐摩耗・低摩擦のセ
ラミック材料として、室温から中低温領域で優れた機械
的特性を有する窒化ケイ素焼結体及びその製造方法に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a ceramic material having high wear resistance and low friction, which is used for various mechanical members, cutting tools, sliding members, etc., and has excellent mechanical properties in the range of room temperature to middle and low temperatures. The present invention relates to a silicon nitride sintered body and a method for manufacturing the same.
【０００２】[0002]
【従来の技術】窒化ケイ素（Ｓｉ3Ｎ4）は強度、靭性、
耐食性、耐酸化性、耐熱衝撃性において優れた材料であ
るために、切削工具やガスタービン、軸受等に幅広く使
用されている。さらに最近では、エンジン部品や精密部
品などの構造材料にも使用する研究が進められ、耐摩耗
性等の摩耗特性など性能レベルが苛酷になりつつある。2. Description of the Related Art Silicon nitride (Si 3 N 4 ) is used for strength, toughness,
It is widely used in cutting tools, gas turbines, bearings, etc. because of its excellent corrosion resistance, oxidation resistance, and thermal shock resistance. Furthermore, recently, research has been conducted for use in structural materials such as engine parts and precision parts, and performance levels such as wear characteristics such as wear resistance are becoming severe.
【０００３】例えば、高い耐摩耗性が要求されている特
定の自動車部品等の精密耐摩部品に窒化ケイ素系複合材
料を用いる場合には、超硬合金（ＷＣからなる硬質粒子
とＣｏ等の結合相とからなるサーメット材料）やハイス
のような従来の材料に比べ顕著に高い耐摩耗性が要求さ
れている。For example, when a silicon nitride-based composite material is used for precision wear-resistant parts such as specific automobile parts which require high wear resistance, cemented carbide (hard particles made of WC and a binder phase such as Co) is used. It is required to have a significantly higher wear resistance than conventional materials such as cermet materials consisting of and HSS.
【０００４】しかしながら、窒化珪素系の複合材料は、
これらの材料に比べ高価であるとともに、耐摩耗性は、
その価格レベルに見合うだけの満足したレベルにはない
のが現状である。However, the silicon nitride-based composite material is
It is more expensive than these materials and wear resistance is
The current situation is that we are not satisfied with the price level.
【０００５】なお、「窒化ケイ素系」とは、主結晶相と
して窒化ケイ素（Ｓｉ3Ｎ4）および／又はサイアロンを
含むセラミックスを指す。また、「窒化ケイ素系の複合
材料」とは、窒化ケイ素系セラミックスを主結晶とする
マトリックス中に、それとは異なった成分を分散複合化
させた材料をいう。The term "silicon nitride system" refers to a ceramic containing silicon nitride (Si 3 N 4 ) and / or sialon as a main crystal phase. Further, the "silicon nitride-based composite material" refers to a material in which a different component is dispersed and composited in a matrix having silicon nitride-based ceramics as a main crystal.
【０００６】このような窒化ケイ素系材料においては、
その特性をより一層向上させるために様々な研究が行わ
れている。例えば、特開平１１−１３９８８２号公報並
びに特開平１１−１３９８７４号公報には、窒化ケイ素
粉末と金属チタン粉末とを窒素雰囲気中にて高加速度で
混合することにより、微細な窒化ケイ素粒子と窒化チタ
ン粒子とからなる複合粉末が得られ、この複合粉末を用
いることにより、窒化チタン粒子が窒化ケイ素の粒成長
を抑制し、微細な結晶構造で高強度の窒化ケイ素焼結体
を製造できることが報告されている。In such a silicon nitride material,
Various studies have been conducted to further improve the characteristics. For example, in JP-A-11-139882 and JP-A-11-139874, fine silicon nitride particles and titanium nitride are obtained by mixing silicon nitride powder and titanium metal powder at high acceleration in a nitrogen atmosphere. It is reported that a composite powder consisting of particles and a titanium nitride particle can suppress grain growth of silicon nitride by using this composite powder, and a high-strength silicon nitride sintered body with a fine crystal structure can be produced. ing.
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、前述の
窒化ケイ素焼結体は高強度を示すものの、機械構造用材
料としての摩擦に関する特性、特に現在の省エネルギー
化の傾向に関して最も期待されている無潤滑下での摩擦
を低下させることについては未だ研究されていなかっ
た。However, although the above-mentioned silicon nitride sintered body exhibits high strength, it has the most promising non-lubricating properties in terms of friction properties as a material for machine structural use, especially in the current trend of energy saving. Reducing friction below has not yet been studied.
【０００８】一方、低摩擦係数を有するセラミックス材
料を作製するために一般的に行われる手法としては、窒
化ホウ素、硫化モリブデン、グラファイト等の固体潤滑
材を材料中に分散させる手法がよく知られている。しか
し、これら固体潤滑材の第２相はサブミクロン程度の大
きさでしか分散させることができず、そのため摩擦係数
の低下と耐摩耗特性の向上には限界があった。On the other hand, as a method generally used for producing a ceramic material having a low coefficient of friction, a method of dispersing a solid lubricant such as boron nitride, molybdenum sulfide or graphite in the material is well known. There is. However, the second phase of these solid lubricants can be dispersed only in a size of submicron, so that there is a limit to the reduction of friction coefficient and the improvement of wear resistance.
【０００９】本発明は、このような従来の事情に鑑み、
室温から中低温域で優れた機械的特性を有すると共に、
低い摩擦係数を有し、耐摩耗性に優れた窒化ケイ素系焼
結体およびその製造方法を提供することを目的とする。The present invention has been made in view of such conventional circumstances.
In addition to having excellent mechanical properties from room temperature to mid-low temperature range,
An object of the present invention is to provide a silicon nitride-based sintered body having a low friction coefficient and excellent wear resistance, and a method for producing the same.
【００１０】[0010]
【課題を解決するための手段】本発明はまず、窒化ケイ
素とチタン系窒化物・炭化物、炭化ケイ素及びグラファ
イトあるいはカーボンの組成からなり、平均粒径が１０
０ｎｍ以下で無潤滑中での摩擦係数が０．２以下である
ことを特徴とする窒化ケイ素系複合焼結体である。The present invention first comprises a composition of silicon nitride and titanium-based nitride / carbide, silicon carbide and graphite or carbon, and has an average particle size of 10
A friction coefficient of 0 nm or less and 0.2 or less in a non-lubricated state is a silicon nitride-based composite sintered body.
【００１１】本発明では、３０ｎｍ以下の粒径とされた
窒化ケイ素、金属窒化物及び／又は炭化物およびグラフ
ァイト粉末あるいはカーボン粉末の各原料粉末を混合粉
砕して形成した二次粒子を用い放電プラズマ焼結によっ
て非酸化性雰囲気中で１２００〜１６００℃で焼結した
もので、組織は平均粒径が１００ｎｍ以下、さらに好ま
しくは５０ｎｍ以下の均一な粒径からなるナノ構造を持
つ組織である。金属Ｔｉは焼結中に全てＴｉＮとＴｉＣ
あるいはＴｉＣＮに変化しており、ＴｉＮ粒子がＳｉ3
Ｎ4の粒成長を抑制して組織を微細化するとともに、Ｃ
はＳｉ3Ｎ4、ＴｉＮおよびＴｉＣあるいはＴｉＣＮの重
なる点および粒界に分散している。また一部のＣはＳｉ
Ｃとなる場合もある。In the present invention, discharge plasma firing is performed using secondary particles formed by mixing and pulverizing raw material powders of silicon nitride, metal nitride and / or carbide and graphite powder or carbon powder having a particle size of 30 nm or less. Sintered at 1200 to 1600 ° C. in a non-oxidizing atmosphere by binding, and the structure is a structure having a nanostructure having an average particle size of 100 nm or less, more preferably 50 nm or less. Metal Ti is all TiN and TiC during sintering
Or it has changed to TiCN, and the TiN particles are changed to Si 3
The grain growth of N 4 is suppressed to make the structure finer, and C
Are dispersed at the overlapping points and grain boundaries of Si 3 N 4 , TiN and TiC or TiCN. Some C is Si
It may be C.
【００１２】このような特殊なナノ構造によって、摩耗
特性の優れた窒化ケイ素系複合焼結体となる。また、本
材料は、共摺りだけでなく、鋼等の金属に対しても優れ
ており、摩擦係数は０．２以下、比摩耗量は１．０×１
０-8ｍｍ2／Ｎ以下と低い摩擦係数を有し、耐摩耗性に
も優れたものである。この低摩耗の理由としては、固体
潤滑剤であるＣが微細に分散したこと、及び鋼と凝着し
にくいＴｉ系化合物がナノサイズで分散したためである
と考えられる。Due to such a special nanostructure, a silicon nitride-based composite sintered body having excellent wear characteristics is obtained. Further, this material is excellent not only for co-sliding but also for metals such as steel, the coefficient of friction is 0.2 or less, and the specific wear amount is 1.0 × 1.
0 -8 mm 2 / N have the following low coefficient of friction, it is excellent in wear resistance. It is considered that the reason for this low wear is that C, which is a solid lubricant, is finely dispersed, and that a Ti-based compound that is hard to adhere to steel is dispersed in a nano size.
【００１３】本発明の製造方法は、窒化ケイ素粉末と焼
結助剤粉末、金属チタン粉末およびグラファイト粉末あ
るいはカーボン粉末を一次粒子の平均粒径が３０ｎｍ以
下になるまで混合粉砕し、複合二次粒子を形成して、該
複合二次粒子を成形して成形体とし、該成形体を１２０
０〜１６００℃、窒素雰囲気下にて焼結して焼結体とす
ることを特徴とする。また、本発明の材料特性を発現す
る平均粒径は１００ｎｍ以下、好ましくは５０ｎｍ以下
である。In the manufacturing method of the present invention, silicon nitride powder and sintering aid powder, metallic titanium powder and graphite powder or carbon powder are mixed and pulverized until the average particle diameter of primary particles becomes 30 nm or less, and composite secondary particles are obtained. And the composite secondary particles are molded into a molded body.
It is characterized in that it is sintered at 0 to 1600 ° C. in a nitrogen atmosphere to obtain a sintered body. Further, the average particle size that exhibits the material characteristics of the present invention is 100 nm or less, preferably 50 nm or less.
【００１４】窒化ケイ素、焼結助剤、金属チタン及びグ
ラファイトあるいはカーボンの各粉末を、圧力０．０５
〜１．０ＭＰａの窒素雰囲気中において室温〜２５０℃
の温度にて１０〜３００Ｇの加速度で混合することによ
り、各粉末は３０ｎｍ以下の平均粒径となり、窒化ケイ
素、窒化チタン、炭化チタン、炭窒化チタン、グラファ
イトあるいはカーボンおよびこれらの粒子の表面を覆っ
ているアモルファス相を含む相と共に平均粒径が０．３
μｍ以上である窒化ケイ素系複合二次粒子が形成され
る。なお、焼結助剤としてはＹ2Ｏ3、Ａｌ2Ｏ3等が用い
られる。Powders of silicon nitride, a sintering aid, metallic titanium and graphite or carbon were added at a pressure of 0.05.
Room temperature to 250 ° C. in a nitrogen atmosphere of up to 1.0 MPa
By mixing at an acceleration of 10 to 300 G at a temperature of 10 to 300 G, each powder has an average particle size of 30 nm or less and covers the surface of silicon nitride, titanium nitride, titanium carbide, titanium carbonitride, graphite or carbon and these particles. The average particle size is 0.3 with the phase including the amorphous phase.
Silicon nitride-based composite secondary particles having a size of μm or more are formed. As the sintering aid, Y 2 O 3 , Al 2 O 3 or the like is used.
【００１５】混合手段としては、粉砕を伴う遊星ボール
ミルやアトライターを用いることが好ましい。かかる高
加速度での混合により、金属チタンが下記化学式の各反
応を主に起こして窒化ケイ素、窒化チタン、炭化チタ
ン、炭窒化チタンを微細化してそれぞれ２０ｎｍ以下の
平均粒径を有するものとしていくものと考えられる。
Ｓｉ3Ｎ4＋４Ｔｉ→４ＴｉＮ＋３Ｓｉ
２Ｔｉ＋Ｎ2→２ＴｉＮ
Ｔｉ＋Ｃ→ＴｉＣ
この際にＴｉＮとＴｉＣは互いに固溶し、炭窒化チタン
を形成することが多い。As a mixing means, it is preferable to use a planetary ball mill or an attritor that involves grinding. By such high-acceleration mixing, metallic titanium mainly causes each reaction of the following chemical formulas to refine silicon nitride, titanium nitride, titanium carbide, and titanium carbonitride to have an average particle diameter of 20 nm or less, respectively. it is conceivable that. Si 3 N 4 + 4Ti → 4TiN + 3Si 2Ti + N 2 → 2TiN Ti + C → TiC At this time, TiN and TiC often form a solid solution with each other to form titanium carbonitride.
【００１６】ここで加速度を１０〜３００Ｇに限定する
理由は、１０Ｇ未満では均一な粉末の微細化が起こり難
く、最終的な焼結体の結晶粒径が不均一になってしまう
ためである。また、混合時の加速度が３００Ｇを超える
と、粉砕機におけるポットやボールが摩耗することによ
り不純物が混入されるようになる。The reason why the acceleration is limited to 10 to 300 G is that if it is less than 10 G, it is difficult for the powder to be made uniform and the crystal grain size of the final sintered body becomes uneven. Further, when the acceleration during mixing exceeds 300 G, the pots and balls in the crusher are worn and impurities are mixed.
【００１７】この高加速度で混合する際の温度として
は、室温〜２５０℃、好ましくは５０℃〜２００℃であ
る。この温度領域において上記反応が促進され、短時間
で目的とする２０ｎｍ以下の平均粒径の粉体を基礎とし
た複合二次粒子粉末を得ることができる。混合時間につ
いては、０．５時間未満では反応に伴う微細化が進行せ
ず、５０時間を超えると不純物が混入するため、０．５
〜５０時間とすることが望ましい。なお、混合の際の加
速度、温度、混合時間は、その作製したい粉末の条件に
より適宜制御することが必要である。The temperature for mixing with high acceleration is room temperature to 250 ° C, preferably 50 ° C to 200 ° C. The above reaction is promoted in this temperature range, and the desired composite secondary particle powder based on the powder having an average particle diameter of 20 nm or less can be obtained in a short time. Regarding the mixing time, if the mixing time is less than 0.5 hours, the miniaturization accompanying the reaction does not proceed, and if the mixing time exceeds 50 hours, impurities are mixed.
It is desirable to set the time to 50 hours. In addition, the acceleration, temperature, and mixing time at the time of mixing must be appropriately controlled depending on the conditions of the powder to be produced.
【００１８】また、上記の反応を起こすためには窒素雰
囲気が必要であり、その窒素雰囲気の圧力は０．０５〜
１．０ＭＰａの範囲が好ましく、０．０８〜０．１５Ｍ
Ｐａの範囲がさらに好ましい。窒素雰囲気の圧力が０．
０５ＭＰａ未満では反応の制御が困難であり、また、
１．０ＭＰａを超えると耐圧容器等の特殊な容器が必要
となるので好ましくない。Further, a nitrogen atmosphere is required to cause the above reaction, and the pressure of the nitrogen atmosphere is 0.05 to
The range of 1.0 MPa is preferable, and 0.08 to 0.15 M
The range of Pa is more preferable. The pressure of the nitrogen atmosphere is 0.
If it is less than 05 MPa, it is difficult to control the reaction, and
If it exceeds 1.0 MPa, a special container such as a pressure resistant container is required, which is not preferable.
【００１９】金属チタン粉末の添加量は、特に制限はな
いが、５重量％未満の場合には反応するＴｉの量が少な
過ぎるために、窒化ケイ素を微細化することができな
い。また、添加量が６０重量％を超えると、反応するＴ
ｉの量が多くなり、焼結体の色ムラ等が発生するために
好ましくない。従って、金属チタン粉末の添加量は５〜
６０重量％の範囲が好ましい。Ｃ量が２０重量％を超え
ると、アグレッシブ摩耗が激しくなり、耐摩耗性が低下
する。また、Ｃ量が０．５重量％未満であると、固体潤
滑剤であるＣが不十分となり摩耗係数が増大する。The amount of titanium metal powder added is not particularly limited, but if it is less than 5% by weight, the amount of Ti that reacts is too small, and silicon nitride cannot be made fine. Also, if the addition amount exceeds 60% by weight, the reaction of T
This is not preferable because the amount of i increases and color unevenness of the sintered body occurs. Therefore, the addition amount of titanium metal powder is 5
A range of 60% by weight is preferred. When the amount of C exceeds 20% by weight, aggressive wear becomes severe and wear resistance decreases. If the amount of C is less than 0.5% by weight, the solid lubricant C is insufficient and the wear coefficient increases.
【００２０】以上のような混合粉砕をすることによっ
て、混合中に金属ＴｉからＴｉＮ等へのメカノケミカル
反応が起こり、混合時間が増加するに伴ないＳｉ3Ｎ4の
結晶径は微細化する。そして、最終的には平均粒径が
０．３μｍ以上の二次複合粒子を形成する。By mixing and pulverizing as described above, a mechanochemical reaction from metal Ti to TiN or the like occurs during mixing, and the crystal size of Si 3 N 4 becomes finer as the mixing time increases. Finally, secondary composite particles having an average particle size of 0.3 μm or more are formed.
【００２１】かかる二次複合粒子を成形後、成形体を１
２００〜１６００℃で窒素雰囲気下にて焼結する。焼結
時の熱により、結晶粒同士が一体化し粒成長することが
知られているので、このような加熱に伴う粒成長をでき
るだけ抑制するため、高い圧力をかけて焼結する方法
や、低温、短時間で焼結する方法が有効である。本発明
では、放電プラズマ焼結またはマイクロ波焼結が有効で
ある。After molding the secondary composite particles, a molded body is
Sinter at 200 to 1600 ° C. under a nitrogen atmosphere. It is known that the heat of sintering causes the crystal grains to unite with each other and grow.Therefore, in order to suppress grain growth due to such heating as much as possible, a method of sintering with high pressure or low temperature The method of sintering in a short time is effective. In the present invention, spark plasma sintering or microwave sintering is effective.
【００２２】このような製造方法により、前述の特徴を
もった本発明の新規な窒化ケイ素系複合焼結体が得られ
る。By such a manufacturing method, the novel silicon nitride-based composite sintered body of the present invention having the above-mentioned characteristics can be obtained.
【００２３】[0023]
【発明の実施の形態】本発明における原料粉末として
は、いずれも市販のものでよい。Ｓｉ3Ｎ4粉末の結晶型
は、α型、β型のいずれでもよい。BEST MODE FOR CARRYING OUT THE INVENTION The raw material powder in the present invention may be any commercially available product. The crystal form of the Si 3 N 4 powder may be either α type or β type.
【００２４】かかるＳｉ3Ｎ4粉末で市販の平均粒径０．
５μｍの粉末に、焼結助剤として２．５ｗｔ％のＹ2Ｏ3
粉末と１ｗｔ％のＡｌ2Ｏ3粉末を加え、更に平均粒径１
０μｍの金属Ｔｉ粉末を３０ｗｔ％、平均粒径５μｍの
カーボン粉末を５ｗｔ％添加して０．１ＭＰａの窒素雰
囲気中において５０℃の温度条件で、Ｓｉ3Ｎ4製ボール
を用いた遊星ボールミルにより加速度１５０Ｇで１６時
間混合した。With such Si 3 N 4 powder, a commercially available average particle size of 0.
2.5 wt% Y 2 O 3 as a sintering aid in 5 μm powder
Powder and 1 wt% Al 2 O 3 powder were added, and the average particle size was 1
30 wt% of 0 μm metallic Ti powder and 5 wt% of carbon powder with an average particle size of 5 μm were added and accelerated by a planetary ball mill using Si 3 N 4 balls under a temperature condition of 50 ° C. in a nitrogen atmosphere of 0.1 MPa. Mix for 16 hours at 150G.
【００２５】得られた粉末をＸＲＤにて定性分析を行っ
たところ、Ｓｉ3Ｎ4、ＴｉＮ、ＴｉＣＮ及びＣのピーク
を確認することができた。また、この複合二次粒子粉末
を透過電子顕微鏡で観察した結果、各粒子の平均粒径は
いずれも３０ｎｍ以下であり、それらの粒子はアモルフ
ァス相に覆われている構造であることが分かった。この
得られた複合二次粒子の平均粒径は０．５μｍであっ
た。When the obtained powder was qualitatively analyzed by XRD, peaks of Si 3 N 4 , TiN, TiCN and C could be confirmed. Further, as a result of observing the composite secondary particle powder with a transmission electron microscope, it was found that the average particle diameter of each particle was 30 nm or less, and the particles had a structure covered with an amorphous phase. The average particle size of the obtained composite secondary particles was 0.5 μm.
【００２６】この複合二次粒子をカーボンダイスに充填
した後、通電焼結が可能な放電プラズマ焼結機（ＳＰ
Ｓ）で昇温速度１００℃／ｍｉｎ、保持時間５分で表１
に示す条件で焼結した。また、測温はカーボンダイスを
二色温度計にて測定した。After filling the composite secondary particles in a carbon die, a discharge plasma sintering machine (SP
In S), the heating rate is 100 ° C./min and the holding time is 5 minutes.
Sintered under the conditions shown in. Further, the temperature was measured by using a carbon die with a two-color thermometer.
【００２７】[0027]
【表１】 [Table 1]
【００２８】得られた焼結体は、研削、ラッピング処理
した後、ＸＲＤで組成を評価した他、ボールオンディス
ク試験機で、φ５ｍｍのＳｉ3Ｎ4ボールを用い、０．２
ｍ／ｓｅｃ、摺動距離１０００ｍの無潤滑条件（２５
℃、大気、湿度６０％）１０Ｎの条件で、耐摩耗特性を
評価した。その摩耗係数と比摩耗量を評価した。また、
この焼結体を研摩した後、Ａｒイオンエッチングで薄膜
試験片を作製し、透過電子顕微鏡を用いて平均粒径を評
価した。以上の結果を表２に示す。The obtained sintered body was ground and lapped, and then the composition was evaluated by XRD. In addition, a ball-on-disk tester was used, and a Si 3 N 4 ball of φ5 mm was used.
m / sec, sliding distance 1000 m, non-lubricated condition (25
The wear resistance was evaluated under the conditions of 10 ° C., atmospheric pressure and humidity of 60%. The wear coefficient and the specific wear amount were evaluated. Also,
After polishing this sintered body, a thin film test piece was prepared by Ar ion etching, and the average particle diameter was evaluated using a transmission electron microscope. The above results are shown in Table 2.
【００２９】[0029]
【表２】 [Table 2]
【００３０】実施例Ｃにおいては、φ５ｍｍのＳＵＪ２
ボールを使用し、同様な試験を行った。その結果、摩擦
係数は０．１を示した。また、比摩耗量は０．４×１０
-8ｍｍ2／Ｎであった。In the embodiment C, the SUJ2 having a diameter of 5 mm is used.
A similar test was conducted using balls. As a result, the friction coefficient was 0.1. The specific wear amount is 0.4 × 10
It was −8 mm 2 / N.
【００３１】また、φ５ｍｍのＳｉ3Ｎ4ボールで、２
０、４０、８０Ｎで０．１〜２．０ｍ／ｓｅｃ、摺動距
離１０００ｍの条件で試験を行ない、同様な摩擦係数、
比摩耗量の結果を得た。Also, with a Si 3 N 4 ball of φ5 mm, 2
The test was conducted under the conditions of 0, 40, 80 N at 0.1 to 2.0 m / sec and a sliding distance of 1000 m.
The result of specific wear amount was obtained.
【００３２】実施例２
実施例１と同様に、焼結助剤として２．５ｗｔ％のＹ2
Ｏ3；１ｗｔ％のＡｌ2Ｏ3を加えた平均粒径０．５μｍ
のＳｉ3Ｎ4粉末に、平均粒径１０μｍの金属チタンと、
平均粒径５μｍのカーボン粉末を表３に示すように配合
し、Ｓｉ3Ｎ4ボールを用い、窒素雰囲気０．１ＭＰａ、
温度５０℃、加速度１５０Ｇの条件で遊星ボールミルを
用いて１６時間混合した。得られた複合二次粒子は実施
例１同様、通電焼結が可能な放電プラズマ焼結で表３の
条件で焼結させた。Example 2 As in Example 1, 2.5 wt% Y 2 as a sintering aid was used.
O 3 ; average particle size 0.5 μm to which 1 wt% of Al 2 O 3 is added
Of Si 3 N 4 powder, and titanium metal having an average particle size of 10 μm,
Carbon powder having an average particle size of 5 μm was blended as shown in Table 3, Si 3 N 4 balls were used, and a nitrogen atmosphere was 0.1 MPa.
The mixture was mixed for 16 hours using a planetary ball mill under the conditions of a temperature of 50 ° C. and an acceleration of 150G. As in Example 1, the obtained composite secondary particles were sintered under the conditions of Table 3 by discharge plasma sintering capable of electric current sintering.
【００３３】[0033]
【表３】 [Table 3]
【００３４】得られた焼結体は、実施例１と同様な手法
で評価した。この結果を表４に示す。The obtained sintered body was evaluated in the same manner as in Example 1. The results are shown in Table 4.
【００３５】[0035]
【表４】 [Table 4]
【００３６】[0036]
【発明の効果】本発明は、室温から中低温域（３００℃
以下）で優れた機械的強度を有し、低い摩擦係数を有
し、耐摩耗性に優れた窒化ケイ素系複合焼結体であり、
各種機構部材や切削工具・摺動部材として有用なもので
ある。又、製造方法では、特定の複合二次粒子を用い、
特定の条件で焼結することによって、焼結時の粒成長を
抑制することができて、上記のように優れた特性をもつ
窒化ケイ素系複合焼結体を得ることができる。INDUSTRIAL APPLICABILITY The present invention has a room temperature to a low temperature range (300 ° C.).
The following) is a silicon nitride-based composite sintered body having excellent mechanical strength, a low friction coefficient, and excellent wear resistance,
It is useful as various mechanical members, cutting tools, and sliding members. Also, in the manufacturing method, using a specific composite secondary particles,
By sintering under a specific condition, grain growth during sintering can be suppressed, and a silicon nitride-based composite sintered body having excellent characteristics as described above can be obtained.
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Claims (8)
炭化ケイ素及びグラファイトあるいはカーボンの組成か
らなり、平均粒径が１００ｎｍ以下で無潤滑中での摩擦
係数が０．２以下であることを特徴とする窒化ケイ素系
複合焼結体。1. Silicon nitride and titanium-based nitride / carbide,
A silicon nitride-based composite sintered body comprising a composition of silicon carbide and graphite or carbon, having an average particle size of 100 nm or less and a friction coefficient of 0.2 or less in an unlubricated state.
記載の窒化ケイ素系複合焼結体。2. The average particle size is 50 nm or less.
The described silicon nitride-based composite sintered body.
ていることを特徴とする請求項１又は２記載の窒化ケイ
素複合焼結体。3. The silicon nitride composite sintered body according to claim 1, wherein titanium-based nitrides and carbides are in solid solution with each other.
下であることを特徴とする請求項１ないし３のいずれか
１項に記載の窒化ケイ素系複合焼結体。4. The silicon nitride-based composite sintered body according to claim 1, wherein the specific wear amount is 1.0 × 10 −8 mm 2 / N or less.
タン粉末およびグラファイト粉末あるいはカーボン粉末
を窒化ケイ素とチタン窒化物・炭化物、およびグラファ
イトあるいはカーボン粉末を一次粒子の平均粒径が３０
ｎｍ以下になるまで粉砕混合し、複合二次粒子を形成し
て、該複合二次粒子を成形して成形体とし、該成形体を
１２００〜１６００℃、非酸化性雰囲気下にて焼結して
焼結体とすることを特徴とする窒化ケイ素系複合焼結体
の製造方法。5. A silicon nitride powder and a sintering aid powder, a titanium metal powder and a graphite powder or a carbon powder of silicon nitride and a titanium nitride / carbide, and a graphite or a carbon powder having an average primary particle diameter of 30.
pulverized and mixed to have a particle size of not more than nm to form composite secondary particles, and the composite secondary particles are molded into a molded body, and the molded body is sintered at 1200 to 1600 ° C. in a non-oxidizing atmosphere. A method for producing a silicon nitride-based composite sintered body, comprising:
％、グラファイトあるいはカーボン粉末の添加量が０．
５〜２０重量％である請求項５記載の窒化ケイ素系複合
焼結体の製造方法。6. The amount of titanium metal powder added is 5 to 60% by weight, and the amount of graphite or carbon powder added is 0.
The method for producing a silicon nitride-based composite sintered body according to claim 5, which is 5 to 20% by weight.
ａの窒素雰囲気中において、室温〜２５０℃の温度にて
１０〜３００Ｇの加速度の下で行う請求項５または６記
載の窒化ケイ素系複合焼結体の製造方法。7. The crushing and mixing is performed at a pressure of 0.05 to 1.0 MP.
The method for producing a silicon nitride-based composite sintered body according to claim 5 or 6, which is carried out in a nitrogen atmosphere of a at a temperature of room temperature to 250 ° C under an acceleration of 10 to 300G.
ロ波焼結で行う請求項５ないし７のいずれかに記載の窒
化ケイ素系複合焼結体の製造方法。8. The method for producing a silicon nitride-based composite sintered body according to claim 5, wherein the sintering is performed by spark plasma sintering or microwave sintering.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001222814A JP2003034578A (en) | 2001-07-24 | 2001-07-24 | Silicon nitride-based composite sintered body and method for producing the same |
| US10/311,604 US6844282B2 (en) | 2001-04-20 | 2002-04-18 | Silicon nitride based composite sintered product and method for production thereof |
| CNB028013255A CN100480214C (en) | 2001-04-20 | 2002-04-18 | Silicon nitride based composite sintered product and production method thereof |
| PCT/JP2002/003864 WO2002085812A1 (en) | 2001-04-20 | 2002-04-18 | Silicon nitride based composite sintered product and method for production thereof |
| EP02718611A EP1298106A4 (en) | 2001-04-20 | 2002-04-18 | Silicon nitride based composite sintered product and method for production thereof |
| US11/031,994 US7008893B2 (en) | 2001-04-20 | 2005-01-11 | Silicon nitride-based composite sintered body and producing method thereof |
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| JP2001222814A JP2003034578A (en) | 2001-07-24 | 2001-07-24 | Silicon nitride-based composite sintered body and method for producing the same |
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ID=19056236
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| Country | Link |
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2001
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