JP2003034579A - 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
- Publication number
- JP2003034579A JP2003034579A JP2001222812A JP2001222812A JP2003034579A JP 2003034579 A JP2003034579 A JP 2003034579A JP 2001222812 A JP2001222812 A JP 2001222812A JP 2001222812 A JP2001222812 A JP 2001222812A JP 2003034579 A JP2003034579 A JP 2003034579A
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- Prior art keywords
- silicon nitride
- sintered body
- titanium
- based composite
- nitride
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、各種機械部材や切
削工具・摺動部材等に使用される高耐摩耗・低摩擦のセ
ラミックス材料として、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系複合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 machine 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-based composite 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、エンジン部品などの構
造材料にも使用する研究が進められ、耐摩耗性、硬度な
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 performance levels such as wear resistance and hardness are becoming severe.
【０００３】例えば、高い耐摩耗性が要求されている特
定の自動車部品や塑性加工用の工具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 a specific automobile part that requires high wear resistance or a tool for plastic working, cemented carbide (hard particles made of WC and Co, etc. is bonded). It is required to have significantly higher wear resistance than conventional materials such as cermet materials consisting of phases 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 the friction coefficient.
【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複
合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 composite 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、チタン系化合物及び窒化ホウ素の組成からなり、平
均粒径が１００ｎｍ以下で無潤滑中での摩擦係数が０．
３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。ここでいうチタン系化合物とは主に、窒化チタ
ン、ホウ化チタンである。平均粒径は、１００ｎｍ以下
であることが必要である。１００ｎｍを超えると摩擦時
に粒子脱落や凝着が激しくなり、摩擦係数が低下する。
材料の焼結条件（密度）にもよるが、好ましくは５０ｎ
ｍ以下である。The present invention comprises a composition of silicon nitride, a titanium compound, and boron nitride, and has an average particle size of 100 nm or less and a friction coefficient of 0.
It is a silicon nitride-based composite sintered body characterized by being 3 or less. The titanium-based compound here is mainly titanium nitride or titanium boride. The average particle size needs to be 100 nm or less. If the thickness exceeds 100 nm, the particles are more likely to come off or adhere during friction, resulting in a lower friction coefficient.
Depending on the sintering conditions (density) of the material, it is preferably 50n
m or less.
【００１１】図１が本発明で得られる焼結体のＴＥＭ写
真である。すなわち、２０ｎｍ以下の粒径とされた窒化
ケイ素、窒化ホウ素及び窒化チタン、ホウ化チタンの各
原料粉末の二次粒子を用い放電プラズマ焼結によって窒
素雰囲気中で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５
０ｎｍ以下の均一な粒径からなるナノ構造を持つ組織で
ある。Ｘ線分析及びＥＤＸ分析の結果から、金属Ｔｉは
窒化チタンとホウ化チタンに変化しており、窒化チタン
粒子がＳｉ3Ｎ4の粒成長を抑制して組織を微細化すると
ともに、ホウ化チタンは柱状または板状になって粒界お
よび／又は窒化チタン粒内に分散し、ＢＮは窒化ケイ
素、チタン系化合物の３重点および粒界に分散してい
る。これは、図１のＴＥＭ写真中の５の部分である。FIG. 1 is a TEM photograph of the sintered body obtained by the present invention. That is, secondary particles of each raw material powder of silicon nitride, boron nitride, titanium nitride, and titanium boride having a particle size of 20 nm or less are sintered by discharge plasma sintering at 1200 to 1600 ° C. in a nitrogen atmosphere. so,
The tissue has an average particle size of 100 nm or less, more preferably 5
It is a structure having a nanostructure with a uniform particle size of 0 nm or less. From the results of X-ray analysis and EDX analysis, the metal Ti has changed to titanium nitride and titanium boride, and the titanium nitride particles suppress the grain growth of Si 3 N 4 to make the structure finer and titanium boride. Has a columnar or plate shape and is dispersed in the grain boundaries and / or the titanium nitride grains, and BN is dispersed in the triple points of the silicon nitride and the titanium-based compound and the grain boundaries. This is part 5 in the TEM photograph of FIG.
【００１２】ホウ化チタンの一部は短軸径２０ｎｍ以
下、アスペクト比３以上の柱状または板状のものが良
い。このような柱状粒子を形成することにより、本材料
の機械的特性を向上させることが可能である。A part of titanium boride is preferably columnar or plate-shaped with a minor axis diameter of 20 nm or less and an aspect ratio of 3 or more. By forming such columnar particles, it is possible to improve the mechanical properties of the present material.
【００１３】このような特殊なナノ構造によって、強度
５００ＭＰａ以上、破壊靭性６ＭＰａ・ｍ1/2以上の機
械的特性の優れた窒化ケイ素系複合焼結体となる。ま
た、対Ｓｉ3Ｎ4での摩擦係数は０．３以下、比摩耗量は
２．０×１０-8ｍｍ2／Ｎと低い摩擦係数を有し、耐摩
耗性にも優れたものである。Due to such a special nanostructure, a silicon nitride-based composite sintered body having a strength of 500 MPa or more and a fracture toughness of 6 MPa · m 1/2 or more and excellent mechanical properties is obtained. Further, the friction coefficient with respect to Si 3 N 4 is 0.3 or less, and the specific wear amount is 2.0 × 10 −8 mm 2 / N, which is a low friction coefficient and is excellent in wear resistance. .
【００１４】また、本発明は、窒化ケイ素粉末と焼結助
剤粉末、チタン金属粉末および窒化ホウ素粉末を平均一
次粒径が２０ｎｍ以下になるまで粉砕混合し、二次粒子
を成形して成形体とし、該成形体を１２００〜１６００
℃、窒素雰囲気下にて焼結して焼結体とすることを特徴
とする窒化ケイ素系複合焼結体の製造方法である。In the present invention, the silicon nitride powder, the sintering aid powder, the titanium metal powder and the boron nitride powder are pulverized and mixed until the average primary particle diameter becomes 20 nm or less, and secondary particles are molded to obtain a molded body. And the molded body is 1200 to 1600
A method for producing a silicon nitride-based composite sintered body, which comprises sintering at a temperature of ℃ in a nitrogen atmosphere to obtain a sintered body.
【００１５】窒化ケイ素、窒化ホウ素及び金属チタンの
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
速度で混合すると、各粉末は２０ｎｍ以下の平均一次粒
径となり、窒化ケイ素、窒化チタン、窒化ホウ素、ホウ
化チタ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０．３μｍ以上であ
る窒化ケイ素系複合二次粒子が形成される。When powders of silicon nitride, boron nitride and titanium metal are mixed in a nitrogen atmosphere having a pressure of 0.05 to 1.0 MPa at a temperature of room temperature to 250 ° C. at an acceleration of 10 to 300 G, each powder has a thickness of 20 nm. A silicon nitride-based composite having the following average primary particle size and an average particle size of 0.3 μm or more together with a phase containing silicon nitride, titanium nitride, boron nitride, titanium boride and an amorphous phase covering the surface of these particles. Secondary particles are formed.
【００１６】混合手段としては、粉砕を伴うボールミル
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メカノケ
ミカル反応を主に起こして窒化ホウ素と窒化ケイ素を微
細化してそれぞれ２０ｎｍ以下の平均一次粒径を有する
ものとしていくものと考えられる。
２ＢＮ＋Ｔｉ→ＴｉＢ2＋Ｎ2
Ｓｉ3Ｎ4＋４Ｔｉ→４ＴｉＮ＋３Ｓｉ
２Ｔｉ＋Ｎ2→２ＴｉＮAs the mixing means, it is preferable to use a ball mill or an attritor that involves crushing. It is considered that the metal titanium mainly causes the mechanochemical reaction represented by the following chemical formula by the mixing at high acceleration to refine the boron nitride and the silicon nitride to have an average primary particle diameter of 20 nm or less. 2BN + Ti → TiB 2 + N 2 Si 3 N 4 + 4Ti → 4TiN + 3Si 2Ti + N 2 → 2TiN
【００１７】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ためである。The reason why the acceleration is limited to 10 to 300 G is that if it is less than 10 G, it is difficult to make uniform powder into fine particles, and the crystal grain size of the final sintered body becomes non-uniform. Further, if the acceleration during mixing exceeds 300 G, the pots and balls in the crusher will be worn and impurities will be mixed.
【００１８】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以下の平均一次粒径の粉体を基礎
とした複合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、０．５〜５
０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 at high acceleration is room temperature to 250 ° C, preferably 50 ° C to 200 ° C. In this temperature range, the above reaction is promoted, and a target composite powder based on the powder having an average primary 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,
Impurities are mixed in over 50 hours, so 0.5 to 5
It is desirable to set it to 0 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.
【００１９】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未満では制御が困難であり、また、１．０Ｍ
Ｐａ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 from 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, and 1.0 M
If it exceeds Pa, a special container such as a pressure resistant container is required, which is not preferable.
【００２０】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、窒化ホウ素及び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Ｔｉ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。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 therefore boron nitride and silicon nitride cannot be made fine. On the other hand, if the addition amount exceeds 60% by weight, the amount of Ti that reacts increases, and color unevenness of the sintered body occurs, which is not preferable. Therefore, the addition amount of the metallic titanium powder is preferably in the range of 5 to 60% by weight.
【００２１】また、窒化ホウ素粉末の添加量について
も、特に制限はないものの、十分な低摩擦特性を得るた
めには２重量％以上の窒化ホウ素が必要であり、また、
材料の優れた機械的特性を維持するためには、４０重量
％以下が適当であることから、２〜４０重量％の範囲が
好ましい。The addition amount of the boron nitride powder is also not particularly limited, but 2% by weight or more of boron nitride is required to obtain a sufficiently low friction characteristic, and
In order to maintain the excellent mechanical properties of the material, 40% by weight or less is suitable, so the range of 2 to 40% by weight is preferable.
【００２２】以上のような粉砕混合をすることによっ
て、混合中に金属チタンからチタン系化合物へのメカノ
ケミカル反応が起こり、混合時間が増加するに伴ないＳ
ｉ3Ｎ4の結晶径は微細化することが判った。そして、最
終的には平均粒径が０．３μｍ以上の二次粒子を形成す
る。By pulverizing and mixing as described above, a mechanochemical reaction from titanium metal to a titanium compound occurs during mixing, and as the mixing time increases, S
It was found that the crystal size of i 3 N 4 was miniaturized. Finally, secondary particles having an average particle size of 0.3 μm or more are formed.
【００２３】この二次粒子の内部構造は、粒径が数〜数
十ｎｍ程度のＳｉ3Ｎ4とチタン系化合物が均一に分散し
た構造をもっている。また、ＥＤＸと電子線回折の結果
から、このナノメーターサイズのＳｉ3Ｎ4とチタン系化
合物は主にアモルファスのチタンで包まれたナノ複合構
造を形成していることが判った。The internal structure of the secondary particles has a structure in which Si 3 N 4 having a particle diameter of several to several tens nm and a titanium compound are uniformly dispersed. From the results of EDX and electron diffraction, it was found that the nanometer-sized Si 3 N 4 and the titanium compound mainly form a nanocomposite structure surrounded by amorphous titanium.
【００２４】かかる二次粒子を成形後、成形体を１２０
０〜１６００℃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。焼結法として
は通電焼結が可能な放電プラズマ焼結やマイクロ波焼結
が代表的な焼結法としてあげられる。After molding the secondary particles, the molded body is
Sintering is performed in a nitrogen atmosphere at 0 to 1600 ° C. 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. Typical examples of the sintering method include discharge plasma sintering and microwave sintering, which can perform electric current sintering.
【００２５】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.
【００２６】[0026]
【発明の実施の形態】以下、本発明の窒化ケイ素系複合
焼結体を製造方法と共に説明する。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 Hereinafter, the silicon nitride-based composite sintered body of the present invention will be described together with its manufacturing method. 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.
【００２７】実施例１
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１０μｍの金属
Ｔｉ粉末を３０ｗｔ％、平均粒径５μｍのＢＮ粉末を１
０ｗｔ％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。Example 1 A commercially available powder of Si 3 N 4 having an average particle diameter of 0.5 μm was added to 2.5 wt% Y 2 O 3 powder as a sintering aid and 1 wt.
% Al 2 O 3 powder was added, and further 30 wt% metal Ti powder having an average particle size of 10 μm and 1 BN powder having an average particle size of 5 μm were added.
0 wt% was added and the mixture was mixed for 16 hours at a acceleration of 150 G in 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.
【００２８】得られた粉末をＸＲＤにて定性分析を行っ
たところ、Ｓｉ3Ｎ4、ＴｉＮ、ＴｉＢ2及びＢＮのピー
クを確認することができた。また、この複合粉末を透過
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２０ｎｍ以下であり、それらの粒子はアモルファスの
ＴｉとＳｉに覆われている構造であることが分かった。
この得られた二次複合粒子の平均粒径は０．５μｍであ
った。When the obtained powder was qualitatively analyzed by XRD, peaks of Si 3 N 4 , TiN, TiB 2 and BN could be confirmed. Moreover, as a result of observing this composite powder with a transmission electron microscope, it was found that the average particle size of each particle was 20 nm or less, and that the particles had a structure covered with amorphous Ti and Si.
The average particle size of the obtained secondary composite particles was 0.5 μm.
【００２９】この二次複合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）を用いて昇温速度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
イスにて行なった。After filling the secondary composite particles in a carbon die, a discharge plasma sintering machine (SP
S) was used to sinter under the conditions shown in Table 1 at a temperature rising rate of 100 ° C./min and a holding time of 5 minutes. The temperature was measured with a carbon die.
【００３０】[0030]
【表１】 [Table 1]
【００３１】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
ク試験機を用いてφ５ｍｍのＳｉ3Ｎ4ボールを用い、
０．１ｍ／ｓｅｃの無潤滑条件（２５℃、大気、湿度６
０％）で測定し、その摩擦係数と比摩耗量を評価した。The obtained sintered body was ground and lapped, and then the composition was evaluated by XRD. In addition, using a ball-on-disk tester, Si 3 N 4 balls having a diameter of 5 mm were used.
Unlubricated condition of 0.1 m / sec (25 ° C, atmosphere, humidity 6
0%) to evaluate the friction coefficient and the specific wear amount.
【００３２】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
用いて各粒径を評価した。以上の結果を表２に示す。After polishing the sintered body, a thin film test piece was prepared by Ar ion etching, and each particle size was evaluated using a transmission electron microscope. The above results are shown in Table 2.
【００３３】[0033]
【表２】 [Table 2]
【００３４】また、Ｃの試料についてはＪＩＳ Ｒ１６
０１に準じて破壊強度を測定した結果、平均７５０ＭＰ
ａの強度を示した。さらに、ＪＩＳ Ｒ１６０７に従い
破壊靭性（ＫＩＣ）を測定した結果、６．５ＭＰａ・ｍ
1/2を示した。For the C sample, JIS R16
As a result of measuring the breaking strength according to 01, an average of 750MP
The strength of a was shown. Further, the fracture toughness (K IC ) was measured according to JIS R1607, and as a result, it was 6.5 MPa · m.
It showed 1/2 .
【００３５】実施例２
実施例１と同様に、焼結助剤として、２．５ｗｔ％のＹ
2Ｏ3、１ｗｔ％のＡｌ 2Ｏ3を加えた平均粒径０．５μｍ
のＳｉ3Ｎ4粉末に、平均粒径１０μｍの金属Ｔｉ粉末と
平均粒径５μｍのＢＮ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。Example 2
As in Example 1, 2.5 wt% Y was added as a sintering aid.
2O31 wt% Al 2O3Average particle size of 0.5 μm
Si3NFourIn the powder, metal Ti powder having an average particle size of 10 μm and
BN powder having an average particle size of 5 μm was blended as shown in Table 3,
Si3NFourUsing a ball, nitrogen atmosphere 0.1 MPa, temperature
Using a planetary ball mill under the conditions of 50 ° C and acceleration of 150G
And mixed for 16 hours.
【００３６】[0036]
【表３】 [Table 3]
【００３７】得られた二次粒子は実施例１と同様に通電
焼結が可能な放電プラズマ焼結で表３に示す条件で焼結
した。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 secondary particles were sintered under the conditions shown in Table 3 by discharge plasma sintering capable of conducting current sintering in the same manner as in Example 1. The obtained sintered body was evaluated in the same manner as in Example 1. The results are shown in Table 4.
【００３８】[0038]
【表４】 [Table 4]
【００３９】[0039]
【発明の効果】本発明によればＳｉ3Ｎ4を主成分とする
微細なマトリックス中にチタン系化合物および窒化ホウ
素を主成分とする微細な分散粒子を分散させることによ
って、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
素系複合焼結体が得られる。EFFECTS OF THE INVENTION According to the present invention, fine dispersed particles containing a titanium compound and boron nitride as main components are dispersed in a fine matrix containing Si 3 N 4 as a main component, so that the temperature range from room temperature to medium to low temperature can be improved. In addition to excellent mechanical properties, a silicon nitride-based composite sintered body having a low friction coefficient and excellent wear resistance can be obtained.
【図１】本発明で得られた焼結体のＴＥＭ写真である。FIG. 1 is a TEM photograph of a sintered body obtained in the present invention.
Claims (8)
ウ素の組成からなり、平均粒径が１００ｎｍ以下で無潤
滑中での摩擦係数が０．３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. A silicon nitride-based composite calcination comprising a composition of silicon nitride, a titanium-based compound and boron nitride, having an average particle size of 100 nm or less and a friction coefficient of 0.3 or less in the absence of lubrication. Union.
チタンであることを特徴とする請求項１記載の窒化ケイ
素系複合焼結体。2. The silicon nitride-based composite sintered body according to claim 1, wherein the titanium-based compound is titanium nitride or titanium boride.
て、窒化ケイ素と窒化チタンの粒界および窒化チタン粒
内に分散し、窒化ホウ素は５０ｎｍ以下の大きさで、窒
化ケイ素およびチタン系化合物の３重点並びに粒界に分
散していることを特徴とする請求項１または２記載の窒
化ケイ素系複合焼結体。3. Titanium boride is columnar or plate-shaped and is dispersed in grain boundaries of silicon nitride and titanium nitride and in titanium nitride grains, and boron nitride has a size of 50 nm or less, and silicon nitride and titanium compounds are used. 3. The silicon nitride-based composite sintered body according to claim 1 or 2, wherein the silicon nitride-based composite sintered body is dispersed in the triple points and grain boundaries.
下、アスペクト比３以上の柱状または板状である請求項
３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 3, wherein a part of titanium boride is columnar or plate-shaped with a minor axis diameter of 20 nm or less and an aspect ratio of 3 or more.
タン粉末および窒化ホウ素粉末を平均一次粒径が２０ｎ
ｍ以下になるまで粉砕混合し、二次粒子を成形して成形
体とし、該成形体を１２００〜１６００℃、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窒化ケイ
素系複合焼結体の製造方法。5. A silicon nitride powder, a sintering aid powder, a titanium metal powder and a boron nitride powder having an average primary particle size of 20 n.
A silicon nitride, which is pulverized and mixed until the particle size becomes m or less, molded into secondary particles, and molded into a compact, and the compact is sintered in a nitrogen atmosphere at 1200 to 1600 ° C. to obtain a sintered compact. Method for producing system-based composite sintered body.
％、窒化ホウ素粉末の添加量が２〜４０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 method for producing a silicon nitride-based composite sintered body according to claim 5, wherein the amount of the metallic titanium powder added is 5 to 60% by weight, and the amount of the boron nitride powder added is 2 to 40% 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 |
|---|---|---|---|
| JP2001222812A JP2003034579A (en) | 2001-07-24 | 2001-07-24 | Silicon-nitride-based composite sintered body and method for producing the same |
| PCT/JP2002/003864 WO2002085812A1 (en) | 2001-04-20 | 2002-04-18 | Silicon nitride based composite sintered product and method for production thereof |
| US10/311,604 US6844282B2 (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 |
| CNB028013255A CN100480214C (en) | 2001-04-20 | 2002-04-18 | Silicon nitride based composite sintered product and production method 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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| JP2001222812A JP2003034579A (en) | 2001-07-24 | 2001-07-24 | Silicon-nitride-based composite sintered body and method for producing the same |
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ID=19056234
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| Country | Link |
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2001
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