JP4537669B2 - Silicon carbide-based bonded component and method for manufacturing the same - Google Patents

Description

【００６３】
表１、図６および図７から明らかなように、実施例１および実施例２の接合方法で作製した接合体は曲げ強度の値にばらつきがあるものの、比較例１〜３による接合体に比べて曲げ強度の値が大幅に向上していることが分かる。また、実施例１および実施例２の接合方法で作製した接合体は、母材と同等の高い熱伝導率を示しているのに対して、比較例１〜３による接合体は熱伝導率が接合部で大幅に低下することが分かる。なお、実施例１および実施例２における曲げ強度値のばらつきは、接合層における微構造の状態などが影響しているものと考えられる。以下の実施例においては、接合層の微構造と曲げ強度との関係を調べた結果について述べる。
【００６４】
実施例３〜７、比較例４〜５
平均粒子径が2μmの炭化ケイ素（α−ＳｉＣ）粉末と、平均粒子径が0.5μmのカーボン粉末（カーボンブラック）とを、質量比で10：3（＝ＳｉＣ：Ｃ）となるように混合した。さらに、この混合粉末を適当量の有機バインダと共に混合した後、溶媒中に分散させてスラリーを調製した。次いで、圧力鋳込み成形機を用いて、スラリーを成形型内に0.5MPaの圧力で加圧しながら充填した。このようにして、所定の成形体密度を有する板状成形体を作製した。
【００６５】
次に、上記した板状成形体を自然乾燥した後、2個の板状成形体を有機系接着剤で接着した。この接着物を不活性ガス雰囲気中にて100〜600℃の温度で加熱・保持し、有機バインダを脱脂すると共に、有機系接着剤層をカーボンが主体の多孔質体とした。この際、有機系接着剤の濃度や塗布方法を調節して、接着層の厚さが異なる試料を複数作製した。これらの予備接合体を減圧下または不活性ガス雰囲気中にて1400℃以上の温度に加熱し、この加熱状態を維持した成形体および接合層（多孔質体）に溶融したシリコンを含浸した。
【００６６】
溶融シリコンの含浸工程において、それぞれ2個の板状成形体をそれぞれ反応焼結させてＳｉＣ基反応焼結体とする同時に、これらＳｉＣ基反応焼結体を反応焼結接合層で接合した接合体を得た。得られた各接合体について、反応焼結接合層を構成するＳｉＣ結晶粒の平均結晶粒径を測定した。さらに、各接合体の曲げ強度を、実施例１と同様にして測定した。その結果を表２および図８に示す。なお、表２中の比較例は反応焼結ＳｉＣ結晶粒の平均結晶粒径を本発明の範囲外としたものであり、本発明との比較のために示したものである。
【００６７】
【表２】

【００６８】
表２および図８から明らかなように、反応焼結接合層を構成するＳｉＣ結晶粒の平均結晶粒径を1〜30μmの範囲に制御した場合に、優れた強度を有する接合体が得られることが分かる。これらの接合層において、反応焼結ＳｉＣ結晶粒の隙間にはネットワーク構造のＳｉ相が連続して存在していた。なお、反応焼結ＳｉＣ結晶粒の平均結晶粒径と強度との関係は、ＳｉＣ基反応焼結体を接着した後に溶融シリコンを含浸した場合においても同様な傾向を示した。
【００６９】
実施例８〜１４
平均粒子径が1.2μmの炭化ケイ素（α−ＳｉＣ）粉末と、平均粒子径が0.05μmのカーボン粉末（カーボンブラック）とを、質量比で10：5（＝ＳｉＣ：Ｃ）となるように混合した。さらに、この混合粉末を適当量の有機バインダと共に混合した後、溶媒中に分散させてスラリーを調製した。次いで、圧力鋳込み成形機を用いて、スラリーを成形型内に2MPaの圧力で加圧しながら充填した。このようにして、所定の成形体密度を有する板状成形体を作製した。
【００７０】
次に、上記した板状成形体を自然乾燥した後、2個の板状成形体を有機系接着剤で接着した。この接着物を不活性ガス雰囲気中にて400℃の温度で加熱・保持し、有機バインダを脱脂すると共に、有機系接着剤層をカーボンが主体の多孔質体とした。この際、有機系接着剤の濃度や塗布方法を調節して、接着層の厚さが異なる試料を複数作製した。これらの予備接合体を減圧下または不活性ガス雰囲気中にて1400℃以上の温度に加熱し、この加熱状態を維持した成形体および接合層（多孔質体）に溶融したシリコンを含浸した。
【００７１】
溶融シリコンの含浸工程において、それぞれ2個の板状成形体をそれぞれ反応焼結させてＳｉＣ基反応焼結体とする同時に、これらＳｉＣ基反応焼結体を反応焼結接合層で接合した接合体を得た。得られた各接合体について、反応焼結接合層の平均厚さを測定した。さらに、各接合体の曲げ強度を、実施例１と同様にして測定した。その結果を表３および図９に示す。
【００７２】
【表３】

【００７３】
表３および図９から明らかなように、反応焼結接合層の厚さが1〜200μmの範囲の場合に、優れた強度を有する接合体が再現性よく得られることが分かる。なお、これらの接合層は反応焼結ＳｉＣ結晶粒とその隙間に存在するネットワーク構造のＳｉ相とから構成されていた。反応焼結接合層の厚さと強度との関係は、ＳｉＣ基反応焼結体を接着した後に溶融シリコンを含浸した場合においても同様な傾向を示した。
【００７４】
実施例１５〜１８
平均粒子径が5μmの炭化ケイ素（α−ＳｉＣ）粉末と、平均粒子径が0.5μmのカーボン粉末（カーボンブラック）とを、質量比で10：4（＝ＳｉＣ：Ｃ）となるように混合した。さらに、この混合粉末を適当量の有機バインダと共に混合した後、溶媒中に分散させてスラリーを調製した。次いで、圧力鋳込み成形機を用いて、スラリーを成形型内に1.5MPaの圧力で加圧しながら充填した。このようにして、所定の成形体密度を有する板状成形体を作製した。
【００７５】
次に、上記した板状成形体を自然乾燥した後、2個の板状成形体を有機系接着剤で接着した。この接着物を不活性ガス雰囲気中にて100〜600℃の温度で加熱・保持し、有機バインダを脱脂すると共に、有機系接着剤層をカーボンが主体の多孔質体とした。この際、有機系接着剤の濃度や塗布方法を調節して、接着層の厚さが異なる試料を複数作製した。これらの予備接合体を減圧下または不活性ガス雰囲気中にて1400℃以上の温度に加熱し、この加熱状態を維持した成形体および接合層（多孔質体）に溶融したシリコンを含浸した。
【００７６】
溶融シリコンの含浸工程において、それぞれ2個の板状成形体をそれぞれ反応焼結させてＳｉＣ基反応焼結体とする同時に、これらＳｉＣ基反応焼結体を反応焼結接合層で接合した接合体を得た。得られた各接合体について、反応焼結接合層の気孔率を測定した。さらに、各接合体の曲げ強度を、実施例１と同様にして測定した。その結果を表４および図１０に示す。
【００７７】
【表４】

【００７８】
表４および図１０から明らかなように、反応焼結接合層の気孔率が5％以下の場合、特に気孔率が2％以下の場合に、優れた強度を有する接合体が再現性よく得られることが分かる。なお、これらの接合層は反応焼結ＳｉＣ結晶粒とその隙間に存在するネットワーク構造のＳｉ相とから構成されていた。反応焼結接合層の気孔率と強度との関係は、ＳｉＣ基反応焼結体を接着した後に溶融シリコンを含浸した場合においても同様な傾向を示した。
【００７９】
実施例１９〜２１、参考例１〜２
平均粒子径が５μｍの炭化ケイ素（α−ＳｉＣ）粉末と、平均粒子径が１μｍのカーボン粉末（カーボンブラック）とを、質量比で１０：２（＝ＳｉＣ：Ｃ）となるように混合した。さらに、この混合粉末を適当量の有機バインダと共に混合した後、溶媒中に分散させてスラリーを調製した。次いで、圧力鋳込み成形機を用いて、スラリーを成形型内に５ＭＰａの圧力で加圧しながら充填した。このようにして、所定の成形体密度を有する板状成形体を作製した。
【００８０】
次に、上記した板状成形体を自然乾燥した後、2個の板状成形体を有機系接着剤で接着した。この接着物を不活性ガス雰囲気中にて400℃の温度で加熱・保持し、有機バインダを脱脂すると共に、有機系接着剤層をカーボンが主体の多孔質体とした。この際、有機系接着剤の濃度を調節して、接着剤の塗布濃度が異なる試料を複数作製した。これらの予備接合体を減圧下または不活性ガス雰囲気中にて1400℃以上の温度に加熱し、この加熱状態を維持した成形体および接合層（多孔質体）に溶融したシリコンを含浸した。
【００８１】
溶融シリコンの含浸工程において、それぞれ2個の板状成形体をそれぞれ反応焼結させてＳｉＣ基反応焼結体とする同時に、これらＳｉＣ基反応焼結体を反応焼結接合層で接合した接合体を得た。得られた各接合体について、反応焼結接合層のＳｉ含有量を測定した。さらに、各接合体の曲げ強度を、実施例１と同様にして測定した。その結果を表５および図１１に示す。
【００８２】
【表５】

【００８３】
表５および図１１から明らかなように、反応焼結接合層のＳｉ含有量が5〜50体積％の場合に、優れた強度を有する接合体が再現性よく得られることが分かる。なお、これらの接合層は反応焼結ＳｉＣ結晶粒とその隙間に存在するネットワーク構造のＳｉ相とから構成されていた。反応焼結接合層のＳｉ含有量と強度との関係は、ＳｉＣ基反応焼結体を接着した後に溶融シリコンを含浸した場合においても同様な傾向を示した。
【００８４】
実施例２２〜２３
平均粒子径が０．５μｍの炭化ケイ素（α−ＳｉＣ）粉末と、平均粒子径が０．０１μｍのカーボン粉末（カーボンブラック）とを、質量比で１０：３（＝ＳｉＣ：Ｃ）となるように混合した。さらに、この混合粉末を適当量の有機バインダと共に混合した後、溶媒中に分散させてスラリーを調製した。次いで、圧力鋳込み成形機を用いて、スラリーを成形型内に１ＭＰａの圧力で加圧しながら充填した。このようにして、所定の成形体密度を有する板状成形体を作製した。
【００８５】
次に、上記した板状成形体を自然乾燥した後、2個の板状成形体を有機系接着剤で接着した。この接着物を不活性ガス雰囲気中にて100〜700℃の温度で加熱・保持し、有機バインダを脱脂すると共に、有機系接着剤層をカーボンが主体の多孔質体とした。この際、有機系接着剤層をカーボン主体の多孔質体とする熱処理において、昇温速度を調節して気孔径分布が異なる試料を作製した。これらの予備接合体を減圧下または不活性ガス雰囲気中にて1400℃以上の温度に加熱し、この加熱状態を維持した成形体および接合層（多孔質体）に溶融したシリコンを含浸した。
【００８６】
溶融シリコンの含浸工程において、それぞれ２個の板状成形体をそれぞれ反応焼結させてＳｉＣ基反応焼結体とする同時に、これらＳｉＣ基反応焼結体を反応焼結接合層で接合した接合体を得た。このようにして、接合層が３層構造になっている接合体（実施例２２）と１層構造の接合体（実施例２３）とを作製した。なお、反応焼結接合層の微構造は金属顕微鏡で観察して同定した。さらに、各接合体の曲げ強度を、実施例１と同様にして測定した。その結果を表６および図１２に示す。
【００８７】
【表６】

【００８８】
表６および図１２から明らかなように、3層構造の反応焼結接合層を有する場合に、より優れた強度を有する接合体が再現性よく得られ、接合体の耐久性や信頼性を高めることができる。なお、反応焼結接合層の構造と強度との関係は、ＳｉＣ基反応焼結体を接着した後に溶融シリコンを含浸した場合においても同様な傾向を示した。
【００８９】
実施例２４〜３０
上記した実施例２２において、熱処理における昇温速度を調節して気孔径分布が異なる試料を複数作製する以外は、実施例２２と同様にして接合体をそれぞれ作製した。これら各接合体において、３層構造の反応焼結接合層における中央層の平均厚さを測定した。さらに、各接合体の曲げ強度を、実施例１と同様にして測定した。その結果を表７および図１３に示す。
【００９０】
【表７】

【００９１】
表７および図１３から明らかなように、3層構造の反応焼結接合層における中央層の厚さが0.5〜100μmの範囲の場合に、より優れた強度を有する接合体が再現性よく得られ、接合体の耐久性や信頼性を高めることができる。なお、反応焼結接合層の構造と強度との関係は、ＳｉＣ基反応焼結体を接着した後に溶融シリコンを含浸した場合においても同様な傾向を示した。
【００９２】
実施例３１〜３７
上記した実施例２２において、熱処理における昇温速度を調節して気孔径分布が異なる試料を複数作製する以外は、実施例２２と同様にして接合体をそれぞれ作製した。これら各接合体において、３層構造の反応焼結接合層における中央層と側面層の各Ｓｉ含有量を測定した。また、これらＳｉ含有量が側面層の中央層に対するＳｉ含有比を求めた。さらに、各接合体の曲げ強度を、実施例１と同様にして測定した。その結果を表８および図１４に示す。
【００９３】
【表８】

【００９４】
表８および図１４から明らかなように、中央層に対する各側面層のＳｉ含有比が10〜70％高い場合に、より優れた強度を有する接合体が再現性よく得られ、接合体の耐久性や信頼性を高めることができる。なお、反応焼結接合層の構造と強度との関係は、ＳｉＣ基反応焼結体を接着した後に溶融シリコンを含浸した場合においても同様な傾向を示した。
【００９５】
【発明の効果】
以上説明したように、本発明の炭化ケイ素基接合部品によれば、ＳｉＣ基反応焼結体からなる複数の部品ユニット間の接合強度を再現性よく高めることができる。従って、優れた強度、耐久性、信頼性などを有する炭化ケイ素基接合部品、特に大型構造物や複雑形状部品などを安定して提供することが可能となる。また、本発明の炭化ケイ素基接合部品の製造方法によれば、ＳｉＣ基反応焼結体からなる複数の部品ユニットを高強度に接合することができるため、例えば大型構造物や複雑形状部品などを効率よくかつ低コストで作製することが可能となる。
【図面の簡単な説明】
【図１】 本発明の一実施形態による炭化ケイ素基接合部品の概略構造を示す斜視図である。
【図２】 図１に示す炭化ケイ素基接合部品の接合層部分の微構造を模式的に示す拡大断面図である。
【図３】 図１に示す炭化ケイ素基接合部品の接合層の層構造を模式的に示す断面図である。
【図４】 本発明の第１の製造方法による炭化ケイ素基接合部品の製造工程を示す断面である。
【図５】 本発明の第２の製造方法による炭化ケイ素基接合部品の製造工程を示す断面である。
【図６】 本発明の実施例による炭化ケイ素基接合部品の曲げ強度の測定結果を比較例の測定結果と共に示す図である。
【図７】 本発明の実施例による炭化ケイ素基接合部品の熱伝導率の測定結果を比較例の測定結果と共に示す図である。
【図８】 本発明の実施例による炭化ケイ素基接合部品の接合層における炭化ケイ素結晶粒の平均結晶粒径と曲げ強度との関係を示す図である。
【図９】 本発明の実施例による炭化ケイ素基接合部品の接合層の厚さと曲げ強度との関係を示す図である。
【図１０】 本発明の実施例による炭化ケイ素基接合部品の接合層の気孔率と曲げ強度との関係を示す図である。
【図１１】 本発明の実施例による炭化ケイ素基接合部品の接合層のシリコン含有量と曲げ強度との関係を示す図である。
【図１２】 本発明の実施例による炭化ケイ素基接合部品の接合層の層構造と曲げ強度との関係を示す図である。
【図１３】 本発明の実施例による炭化ケイ素基接合部品の3層構造接合層における中央層の厚さと曲げ強度との関係を示す図である。
【図１４】 本発明の実施例による炭化ケイ素基接合部品の3層構造接合層におけるシリコン含有比の厚さと曲げ強度との関係を示す図である。
【符号の説明】
１……炭化ケイ素基接合部品、２，３……炭化ケイ素基反応焼結体からなる部品ユニット、４……反応焼結接合層、５……炭化ケイ素結晶粒、６……遊離シリコン相、２１……成形体、２２……有機系接着剤層、２５，２８……炭化ケイ素基反応焼結体、２６……接合体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a silicon carbide based bonded part having improved mechanical characteristics such as strength and thermal characteristics such as thermal conductivity, and a method for manufacturing the same.
[0002]
[Prior art]
Silicon carbide (SiC) ceramics have excellent properties such as environmental resistance, heat resistance, wear resistance, high rigidity, high thermal conductivity, and low thermal expansion, so they are used as high temperature structural members and wear resistant members. Has been. In particular, practical application to semiconductor-related parts such as jigs for semiconductor manufacturing apparatuses has been promoted in recent years by utilizing the characteristics of SiC ceramics. In addition, research into the application of energy equipment such as nuclear power and gas turbines, industrial equipment such as pump parts, mechanical seal parts, sliding parts, heat exchanger parts, etc. is also underway.
[0003]
As a method for producing SiC ceramics, a reactive sintering method is known in addition to a powder sintering method using a sintering aid similar to a normal ceramic material. The SiC reactive sintering method is, for example, forming a mixture of SiC powder as an aggregate and carbon powder or resin into a desired shape, and heating the molded body to a temperature higher than the melting temperature of silicon, This is done by impregnation. The reactive sintering of SiC is a sintering method involving the reaction of carbon and silicon. The SiC-based reaction sintered body has the advantage that the sintering temperature is lower than that of the powder sintering method and the dimensional shrinkage during sintering is small, so that it can be manufactured in a near net and the processing cost can be reduced. .
[0004]
By the way, when the SiC-based reaction sintered body as described above is applied to various apparatus parts and members, it may be difficult to produce a large structure or a complex-shaped part with an integral reaction sintered body. . In such a case, it is conceivable that a plurality of SiC-based reaction sintered bodies are prepared as component units, and these component units are joined to produce a large structure or a complex shaped component. Known methods for joining ceramic members include, for example, a joining method using a brazing material containing an active metal and a brazing method after metalizing the ceramic member surface. Since the metal layer remains as a bonding layer in the legal method, there is a problem that the heat resistance of the bonded component is limited by the heat resistance temperature of the bonding layer (metal layer).
[0005]
On the other hand, Patent Document 1 discloses a SiC body (a SiC-based sintered body, or a molded body or a calcined body as a precursor thereof) and a porous SiC body (a molded body, a calcined body, a sintered body in a SiC reactive sintering process). The SiC body and the porous SiC body by superimposing them through a binder layer made of a thermosetting resin containing SiC fine powder and impregnating molten silicon from the upper surface side of the porous SiC body. Is described. In this joining method, the SiC body and the porous SiC body are joined with the reaction sintered SiC layer by reacting carbon in the binder layer with molten silicon.
[0006]
However, in the bonding method described above, since the carbon in the resin binder and the molten silicon impregnated through the porous SiC body are reacted, the reaction generation process of SiC in the bonding layer cannot be sufficiently controlled, The microstructure of the reaction-sintered SiC layer as the bonding layer becomes uneven, a large amount of pores are generated in the reaction-sintered SiC layer, and a free silicon layer is formed in the bonding layer. There is a problem that the strength of can not be sufficiently increased. Further, when a resin binder is used for the adhesive layer, there is a problem that the reaction with the molten silicon tends to be non-uniform, and free carbon tends to remain. Such free carbon causes a decrease in bonding strength.
[0007]
[Patent Document 1]
Japanese Patent Publication No. 5-79630
[0008]
[Problems to be solved by the invention]
As mentioned above, the SiC-based reaction sintered body has the advantage that it can be manufactured in a near net because the dimensional shrinkage at the time of sintering is small. It may be difficult to produce with an integrated SiC-based reaction sintered body. Therefore, it is considered to join a plurality of component units to produce a large structure or a complex shaped part. However, the heat resistance temperature of the joining method using the brazing material is limited by the joining layer (metal layer). There is a difficulty. On the other hand, the conventional bonding method using reactive sintering produces a free silicon layer in the bonding layer, and the control of the microstructure and density of the reactive sintered SiC layer (bonding layer) is insufficient. It has not yet been achieved to obtain high-strength bonded parts.
[0009]
The present invention has been made to cope with such problems, and by controlling the microstructure of the bonding layer using reactive sintering, it is possible to enhance mechanical properties such as strength with good reproducibility. An object of the present invention is to provide a silicon carbide-based bonded part and a method for manufacturing the same.
[0010]
[Means for Solving the Problems]
  The silicon carbide based bonded component of the present invention is a silicon carbide based bonded component formed by bonding a plurality of component units made of a silicon carbide based reactive sintered body via a bonding layer, wherein the bonding layer has an average crystal grain size Is mainly composed of silicon carbide crystal grains in the range of 0.1 to 30 μm and a silicon phase continuously present in a network form in the gaps between the silicon carbide crystal grains.And containing the silicon phase in the range of 5 to 50% by volume.It is characterized by that.
[0011]
In the silicon carbide-based bonded component of the present invention, a plurality of component units are formed by a bonding layer mainly composed of silicon carbide crystal grains and a silicon phase continuously present in the gap in the form of a network, that is, a reactive sintered bonding layer. They are joined together. In such a reactive sintered bonding layer, in the present invention, the silicon carbide crystal grains and the microstructure of the silicon phase existing in the gaps, specifically, the average crystal grain size of the silicon carbide crystal grains and the network structure of the silicon phase, etc. Since it is controlled, the strength of the bonding layer itself and the bonding strength to the component unit can be increased with good reproducibility. Also, thermal characteristics such as thermal conductivity can be enhanced. By these, it becomes possible to provide a silicon carbide based bonded part having excellent strength, durability, reliability, and thermal characteristics.
[0012]
  The first method for manufacturing a silicon carbide-based bonded part according to the present invention corresponds to the plurality of component units in manufacturing a silicon carbide-based bonded part by bonding a plurality of component units made of a silicon carbide-based reaction sintered body. A step of producing a plurality of molded bodies, a step of bonding the plurality of molded bodies with an organic adhesive, a heat treatment after bonding the plurality of molded bodies, and a bonding portion formed by the organic adhesive with carbon. Including a step of forming a porous body having a porosity of 20 to 70% as a main component and an adhesive portion made of the porous body, the plurality of molded bodies are impregnated with molten silicon, Each of the molded bodies is subjected to reaction sintering to form the plurality of component units, and between the plurality of component units, the silicon carbide crystal grains having a reaction-generated average crystal grain size in the range of 0.1 to 30 μm and the silicon carbide Crystal grain Present continuously in network form in the gapIn the range of 5-50% by volumeAnd a step of integrally bonding with a bonding layer mainly composed of a silicon phase.
[0013]
  The second method for manufacturing a silicon carbide-based bonded component is the method for manufacturing a silicon carbide-based bonded component by bonding a plurality of component units made of a silicon carbide-based bonded component. Removing the silicon present on the bonding surfaces of the plurality of component units, bonding the bonding surfaces of the plurality of component units with an organic adhesive, and heat treatment after bonding the plurality of component units Then, the step of making the bonded portion made of the organic adhesive into a porous body mainly composed of carbon and having a porosity of 20 to 70%, and the bonded portion made of the porous body are impregnated with molten silicon. The plurality of component units are continuously present in the form of a network in the gap between the silicon carbide crystal grains having an average crystal grain size in the range of 0.1 to 30 μm produced by reaction.In the range of 5-50% by volumeAnd a step of integrally bonding with a bonding layer mainly composed of a silicon phase.
[0014]
In the method for producing a silicon carbide-based bonded component according to the present invention, a plurality of component units made of a silicon carbide-based reactive sintered body are used to form an organic adhesive layer used for bonding a molded body or a sintered body and molten silicon. Bonding is integrated with a reaction-sintered bonding layer based on the reaction. That is, a plurality of component units made of a silicon carbide-based reaction sintered body are integrally joined with the silicon carbide crystal grains produced by reaction and the silicon phase continuously present in the gaps in the form of a network. According to such a reaction-sintered bonding layer, since a plurality of component units can be bonded with high strength, it becomes possible to efficiently produce a large structure or a complex shaped component at a low cost. . Also, thermal characteristics such as thermal conductivity can be enhanced.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, modes for carrying out the present invention will be described.
FIG. 1 is a cross-sectional view schematically showing a schematic structure of a silicon carbide (SiC) -based bonded component according to an embodiment of the present invention. The SiC-based joining component 1 shown in the figure has a plurality of component units, specifically, first and second component units 2 and 3 made of a SiC-based reaction sintered body. The component units 2 and 3 made of these SiC-based reaction sintered bodies are bonded via the bonding layer 4, and the SiC-based bonded component 1 is constituted by these. In addition, although the joining component 1 using the two component units 2 and 3 is shown here, the number of the component units constituting the joining component 1 is not limited to two, but three or more. May be.
[0016]
The bonding layer 4 is a reaction-sintered bonding layer using reaction sintering of SiC. As shown in an enlarged view of the fine structure in FIG. 2, SiC crystal grains 5 generated by reaction sintering, and these SiC crystal grains 5. And a free silicon (Si) phase 6 continuously present in a network in the gap. Such a reaction-sintered bonding layer 4 controls the microstructure of the reaction-sintered SiC crystal grains 5 and the free Si phase 6 so that the strength of the bonding layer 4 itself and the bonding strength to the component units 2 and 3, It is possible to increase the strength of the joined component 1.
[0017]
As for the microstructure of the SiC crystal grains 5, the particle shape is controlled so that the average crystal grain size is in the range of 0.1 to 30 μm. If the average crystal grain size of the SiC crystal grains 5 exceeds 30 μm, the strength of the reaction-sintered bonding layer 4 itself is lowered, and the strength between the component units 2 and 3 cannot be expressed sufficiently. On the other hand, if the average crystal grain size of the SiC crystal grains 5 is less than 0.1 μm, it is impossible to stably obtain a microstructure in which the free Si phase 6 exists in a network form from the viewpoint of the manufacturing process. The yield of the joint is reduced, and the reliability and durability of the joining component 1 are insufficient.
[0018]
It is more preferable to control the average crystal grain size of the reaction sintered SiC crystal grains 5 as described above in the range of 0.5 to 10 μm. The average crystal grain size of the SiC crystal grains 5 is obtained by mirror-finishing an arbitrary cross section of the bonding layer 4 and then observing the structure using an optical microscope (metal microscope) or an electron microscope, and image-processing the enlarged structure photograph. The value obtained by doing
[0019]
Regarding the microstructure of the free Si phase 6 existing in the gaps between the SiC crystal grains 5, it is important to have a continuous network structure. When the network structure of the free Si phase 6 is divided, a relatively large amount of pores are generated, and the strength of the reaction sintered bonding layer 4 is lowered. In other words, the reaction-sintered bonding layer 4 is formed into a dense reaction-sintered layer by allowing the free Si phase 6 to continuously exist in the gaps between the SiC crystal grains 5. The porosity of the reaction sintered bonding layer 4 is preferably 5% or less, for example. When the porosity exceeds 5%, the bonding strength between the component units 2 and 3 is not sufficiently exhibited, and thus, for example, characteristics required for a structural material cannot be sufficiently obtained.
[0020]
Further, the content of the free Si phase 6 in the reaction sintered bonding layer 4 is preferably in the range of 5 to 50% by volume. When the content of the free Si phase 6 is less than 5% by weight, the network structure is easily divided. That the content of the free Si phase 6 in the bonding layer 4 exceeds 50% by volume means an increase in the free Si phase 6 that tends to be a starting point of fracture. Accordingly, when the content of the free Si phase 6 is out of the range of 5 to 50% by volume, the strength of the bonding layer 4 itself and the bonding strength between the component units 2 and 3 are likely to be lowered. The content of the free Si phase 6 is desirably in the range of 10 to 40% by volume. The content of the free Si phase 5 is calculated based on the theoretical density of Si and SiC from the image processing result and density of the structure observation photograph.
[0021]
The thickness (average thickness) of the reactive sintered bonding layer 4 is preferably in the range of 1 to 200 μm. The reaction-sintered bonding layer 4 having a thickness of less than 1 μm is difficult to produce in the manufacturing process due to the occurrence of unbonded parts, and the strength of the reaction-sintered bonding layer 4 itself, and hence the bonding component 1 Reliability and durability are also reduced. On the other hand, when the thickness of the reactive sintered bonding layer 4 exceeds 200 μm, it causes a reduction in the strength of the bonded component 1. The thickness of the reactive sintered bonding layer 4 is more preferably in the range of 3 to 120 μm.
[0022]
Furthermore, it is preferable that the reactive sintered bonding layer 4 has a three-layer structure as shown in FIG. The reaction-sintered bonding layer 4 shown in FIG. 3 is located in layers (side layers) 11 and 12 in contact with the component units (SiC-based reaction sintered bodies) 2 and 3 and in the center of these side layers 11 and 12. And a layer (center layer) 13. The side layers 11 and 12 have a structure closer to the SiC-based reaction sintered body constituting the component units 2 and 3 than the central layer 13. The thickness of the central layer 13 is preferably in the range of 0.5 to 100 μm. By interposing the reaction sintered bonding layer 4 having such a three-layer structure between the component units 2 and 3, the reliability and durability of the bonded component 1 can be further improved.
[0023]
Regarding the composition of the side layers 11 and 12 and the central layer 13 in the above-described reaction sintered bonding layer 4 having the three-layer structure, the content ratio of free Si in the side layers 11 and 12 is preferably higher than that of the central layer 13. . Specifically, the side layers 11 and 12 preferably have a free Si content ratio of 10 to 70% higher than that of the central layer 13. Thus, by making the content ratio of free Si of the side layers 11 and 12 higher than that of the central layer 13, the reliability and durability of the joined component 1 can be further enhanced. Such a reaction-sintered bonding layer 4 having a three-layer structure can be obtained by controlling the structure of a porous body mainly composed of carbon based on the heat treatment conditions after bonding with an organic adhesive. it can.
[0024]
The SiC-based joining component 1 of this embodiment includes a microstructure of the reaction-sintered bonding layer 4, specifically, an average crystal grain size of the reaction-sintered SiC crystal grains 5 constituting the reaction-sintered bonding layer 4, and SiC crystal grains. Since the state and content of the free Si phase 6 existing in the gaps 5 and the structure of the reaction sintered bonding layer 4 are controlled, the strength of the reaction sintered bonding layer 4 itself can be increased, It becomes possible to improve the bonding strength between the component units 2 and 3 by the reaction sintered bonding layer 4. By these, the high-strength joining component 1 can be provided with good reproducibility. Furthermore, since the reaction-sintered bonding layer 4 has the same configuration as the SiC-based reaction sintered body constituting the component units 2 and 3, the heat resistance temperature of the bonded component 1 is limited by the bonding layer 4. There is nothing. Also, thermal characteristics such as thermal conductivity can be enhanced.
[0025]
Then, the shape of the component units 2 and 3 made of the SiC-based reaction sintered body is made easy to manufacture, and the component units 2 and 3 previously manufactured in such a shape are integrally formed with the reaction sintered bonding layer 4. By joining, a large-sized structure, a complex shaped part, etc. can be obtained as the SiC-based joining part 1. Such a SiC-based joining component 1 has both the advantages of the SiC-based reaction sintered body constituting the component units 2 and 3 and the advantage as a joined body, and has high strength (higher strength based on the reaction-sintered bonding layer 4). It is possible to increase the bonding strength.
[0026]
In addition, the SiC group reaction sintered body which comprises the component units 2 and 3 is not specifically limited, The SiC group sintered body produced with various reaction sintering methods is applicable. However, since the strength of the SiC-based reaction sintered body itself also affects the strength of the bonded part 1, for example, the bending strength is 500 MPa or more and the fracture toughness value is 3 MPa / m.^1/2It is preferable to use a SiC-based reaction sintered body having the above mechanical characteristics.
[0027]
The SiC-based reaction sintered body having such mechanical characteristics is blended as an aggregate, for example, and based on the SiC crystal grains having an average crystal grain size in the range of 0.1 to 10 μm and the reaction sintered SiC, and the average crystal grains A SiC matrix is composed of SiC crystal grains having a diameter in the range of 0.01 to 2 μm, and free Si phase is, for example, 5 to 50% by volume (more preferably 5 to 30% by volume) in the gaps between the SiC crystal grains of the SiC matrix. It is obtained by making it continuously exist in a network form in the range. SiC which is densified with an appropriate amount of free Si phase, has a free Si phase with a network structure finely and uniformly present in the gaps of SiC crystal grains, and controls the average crystal grain size of SiC crystal grains within an appropriate range According to the base reaction sintered body, good strength, fracture toughness value and the like can be obtained.
[0028]
As described above, according to the SiC-based joint component 1 of the present invention, it is possible to integrally produce a more complex shaped component or a large structure, and further to improve the strength of such a component or structure. It becomes possible to raise. This greatly contributes to the reduction of the manufacturing cost of complex shaped parts and large structures, the improvement of manufacturing efficiency, and the improvement of reliability and durability. In addition, thermal characteristics such as thermal conductivity can be enhanced. A typical strength of the SiC-based bonded component 1 is, for example, an average bending strength of 150 MPa or more and 1000 MPa or less. The typical hardness of the reaction sintered bonding layer 4 is Hv1200 or higher and Hv2200 or lower, and the Young's modulus is 300GPa or higher and 420GPa or lower.
[0029]
The SiC-based bonded component 1 of this embodiment includes a jig for a semiconductor manufacturing apparatus, a semiconductor-related component (such as a heat sink and a dummy wafer), a high-temperature structural member for a gas turbine, a structural member for space and aviation, a mechanical seal member, a brake member, It is suitably used for various apparatus parts and apparatus members such as sliding parts, mirror parts, pump parts, heat exchanger parts, chemical plant element parts and the like. In particular, since the SiC-based bonded component 1 has high strength, it can be applied to apparatus components and members that require strength. This greatly contributes to the expansion of the application range and field of application of inexpensive SiC-based reaction sintered bodies.
[0030]
The SiC-based bonded component 1 of this embodiment is manufactured as follows, for example. Here, the manufacturing method of the joined component 1 to which reaction sintering is applied includes a method (first manufacturing method) of joining a component unit at a stage of a molded body (for example, a molded body made of a mixture of SiC and carbon), It is roughly divided into a method (second manufacturing method) in which the component unit is joined after being made into a sintered body. First, the 1st manufacturing method which joins a component unit in the stage of a molded object is demonstrated with reference to FIG.
[0031]
That is, as shown in FIG. 4A, two or more molded bodies 21 are prepared. The molded body 21 is the basis of the SiC-based reaction sintered body. For example, a mixture of SiC powder and carbon powder, an organic binder, an organic solvent, etc. are added as necessary, and a mixed mixture or slurry is added. For example, a compact that is pressure-molded into a desired shape is used. The compounding ratio of the SiC powder and the carbon powder in the molded body 21 is preferably in the range of 10: 1 to 10:10, and more preferably in the range of 10: 3 to 10: 5. A resin or the like can be used instead of the carbon powder.
[0032]
The mixture of SiC powder and carbon powder is formed into a desired shape by applying, for example, powder pressing or pressure casting. The pressure when applying powder pressure molding is preferably about 0.5 to 2 MPa. A mold press, a rubber press, a cold isostatic press, or the like can be used for pressure molding of the powder. When pressure casting is applied, a slurry is prepared by dispersing the mixture in water or an organic solvent, and the slurry is cast into a molding die while applying pressure to form a desired shape. The pressure during casting is preferably about 0.5 to 10 MPa. By applying such pressure molding, a molded body having an appropriate density (filled state of powder) can be obtained.
[0033]
Next, as shown in FIG. 4B, the two molded bodies 21 are bonded with an organic adhesive 22. The organic adhesive 22 is not particularly limited, and various adhesives can be used as long as carbon remains after the heat treatment. Next, as shown in FIG. 4C, heat treatment is performed to make the organic adhesive 22 a porous body 23 mainly composed of carbon. That is, a preliminary bonded body 24 in which two molded bodies 21 are connected by a porous body 23 mainly composed of carbon is produced.
[0034]
It is preferable that the porosity of the porous body 23 constituting the joint is in the range of 20 to 70%. If the porosity of the porous body 23 is less than 20%, the amount of molten Si impregnated becomes insufficient due to the volume expansion during SiC generation, and free carbon tends to remain. Free carbon becomes a factor of lowering the strength of the bonding layer 4 itself and the bonding strength. On the other hand, if the porosity of the porous body 23 exceeds 70%, the amount of Si existing as a free Si phase after the impregnation step with molten Si increases so that the strength and bonding strength of the bonding layer 4 itself may be lowered. There is.
[0035]
The pre-joint 24 as described above is heated to a temperature not lower than the melting point of Si, specifically 1400 ° C. or higher, and the pre-joint 24 in this heated state is impregnated with molten Si. The impregnation with molten Si is performed, for example, under reduced pressure or in an inert atmosphere. Although depending on the size of the compact 21, the impregnation with molten Si is performed quickly (units of seconds), and then the reaction between the molten Si and the carbon powder is also performed quickly (units of minutes). In such a molten Si impregnation step, the two molded bodies 21 are each subjected to reaction sintering, and at the same time, the porous body 23 at the joint is also subjected to reaction sintering.
[0036]
That is, the carbon in the molded body 21 and the carbon constituting the porous body 23 at the joint portion react with each other in contact with molten Si at a high temperature. For example, the average crystal grain size is larger than the aggregate SiC in the molded body 21. Create small SiC. In the formed body 21 portion, a SiC-based reaction sintered body is formed in which Si that has not participated in the reaction continuously exists in a network form as a free Si phase in the gap between the crystal grains of the aggregate SiC and the reaction sintered SiC. Is done. In the bonded portion, a reactive sintered bonding layer 4 is formed in which free Si phases are continuously present in a network in the gaps between the reactive sintered SiC crystal grains. Simultaneously with the formation of the reactive sintered bonding layer 4, the two SiC-based reactive sintered bodies are integrally bonded.
[0037]
In this way, as shown in FIG. 4D, a joined body 26 in which two SiC-based reaction sintered bodies 25 are joined and integrated by the reaction sintered joining layer 4 is obtained. The joined body 26 is subjected to final processing such as machining and becomes a SiC-based joined component. In addition, according to the reaction sintering process as described above, the sintering shrinkage from the molded body can be extremely reduced. For example, the amount of shrinkage during sintering can be within ± 3%, and further within ± 1%. Thus, the processing cost to the final dimension can be reduced by significantly reducing the amount of shrinkage during sintering.
[0038]
Next, the 2nd manufacturing method which joins a sintered compact is demonstrated with reference to FIG.
First, as shown in FIG. 5A, two or more SiC-based reaction sintered bodies 28 are prepared. As the SiC-based reaction sintered body 28, a sintered body produced through the process for producing a molded body in the first manufacturing method described above, the step of impregnating the molded body with molten Si, and the like can be applied. However, even SiC-based reaction sintered bodies produced in other reaction sintering processes can be used in the same manner.
[0039]
For the two SiC-based reaction sintered bodies 28, Si existing on the bonding surface 29 is previously removed by heat treatment or chemical treatment. In this way, by removing in advance Si existing on the bonding surface 29 of the SiC-based reaction sintered body 28, the final reaction-sintered bonding layer 4 produced in the molten Si impregnation step and the SiC-based reaction are obtained. It becomes possible to increase the adhesion to the sintered body 28 and further the bonding strength.
[0040]
Next, as shown in FIG. 5B, the two SiC-based reaction sintered bodies 28 are bonded with the organic adhesive 22. The organic adhesive 22 is made the porous body 23 in the same manner as in the first method. In this way, as shown in FIG. 5C, the pre-joined body 24 in which the two SiC-based reaction sintered bodies 28 are connected by the porous body 23 mainly composed of carbon is produced. It is preferable that the porosity of the porous body 23 constituting the joint is in the range of 20 to 70% as in the first manufacturing method.
[0041]
The pre-joint 24 as described above is heated to a temperature equal to or higher than the melting point of Si, and the pre-joint 24 in this heated state is impregnated with molten Si. In particular, the molten Si impregnates the porous body 23 at the joint. In this molten Si impregnation step, the porous body 23 at the joint is reactively sintered, and at the same time, the two SiC-based reactive sintered bodies 28 are integrally joined. That is, the carbon constituting the porous body 23 at the joint reacts with molten Si at a high temperature to produce SiC, and free Si phases are continuously present in the gaps between the SiC crystal grains.
[0042]
In this way, the reaction-sintered bonding layer 4 is formed, and at the same time, the two SiC-based reaction sintered bodies 28 are integrally bonded. That is, as shown in FIG. 5 (d), a joined body 26 in which two SiC-based reaction sintered bodies 28 are joined and integrated by the reaction sintered joining layer 4 is obtained. Each of the two SiC-based reaction sintered bodies 28 constitutes a component unit. The joined body 26 is subjected to final processing such as machining and becomes a SiC-based joined component. The reaction-sintered bonding layer 4 is excellent in its own strength, and also has excellent bonding strength with respect to the SiC-based reaction sintered body 28, so that it is possible to bond two SiC-based reaction sintered bodies 28 with high strength. Become.
[0043]
As described above, in the method for manufacturing a SiC-based bonded component, a plurality of component units made of a SiC-based reaction sintered body are combined with the organic adhesive layer 22 used for bonding the molded body 21 and the sintered body 28, molten Si, The reaction sintering joining layer 4 based on the above reaction is joined and integrated. As shown in FIG. 2, the reaction-sintered bonding layer 4 is composed of reaction-sintered SiC crystal grains 5 and Si phases 6 continuously present in the gaps in the form of a network. Strength bonding is realized. Therefore, according to the method for manufacturing a bonded part using such a reaction-sintered bonding layer 4, it is possible to efficiently produce a large structure, a complex-shaped part, or the like at a low cost. In addition, the parts mentioned here include jigs, members, ornaments, and the like that are attached to the apparatus and the like in addition to the parts in a normal sense that constitute a whole by collecting a plurality of parts.
[0044]
【Example】
Next, specific examples of the present invention and evaluation results thereof will be described.
[0045]
Example 1
Silicon carbide (α-SiC) powder having an average particle diameter of 0.5 μm and carbon powder (carbon black) having an average particle diameter of 0.01 μm are mixed so that the mass ratio is 10: 3 (= SiC: C). did. Furthermore, this mixed powder was mixed with an appropriate amount of an organic binder, and then dispersed in a solvent to prepare a slurry. Next, the slurry was filled into the mold while being pressurized at a pressure of 1 MPa using a pressure casting molding machine. In this way, two plate-shaped molded bodies having a predetermined molded body density were produced.
[0046]
Next, the above two plate-like molded bodies were naturally dried and then adhered with an organic adhesive. This adhesive was heated and held at a temperature of 100 to 700 ° C. in an inert gas atmosphere to make the organic adhesive layer a porous body mainly composed of carbon. The porosity of the porous body was 30 to 60%. The pre-joined body in which two plate-shaped compacts are connected with this porous body is heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and the compact and the joining layer that maintain this heating state The (porous body) was impregnated with molten silicon.
[0047]
In this molten silicon impregnation step, each of the two plate-shaped compacts is subjected to reaction sintering to obtain a SiC-based reaction sintered body, and at the same time, a joined body in which these SiC-based reaction sintered bodies are joined together by a reactive sintered joining layer. Got. A plurality of such joined bodies were produced under different manufacturing conditions. When the microstructure of the reaction-sintered bonding layer of the obtained bonded body was observed with an electron microscope, the bonding layer was formed by reacting porous carbon and molten silicon with SiC crystal grains, and a network in the gap between them. It was confirmed that it was composed of a free Si phase continuously present in the shape.
[0048]
In each bonded body described above, the average crystal grain size of the SiC crystal grains in the reaction sintered bonding layer is 0.5 to 20 μm, the porosity is 0 to 20%, the Si content is 10 to 40% by volume, and the average thickness is 10 to It was 120 μm. After polishing the surfaces of these joined bodies, they were subjected to characteristic evaluation described later.
[0049]
Example 2
Silicon carbide (α-SiC) powder having an average particle diameter of 0.2 μm and carbon powder (carbon black) having an average particle diameter of 0.01 μm are mixed so that the mass ratio is 10: 2 (= SiC: C). did. Furthermore, this mixed powder was mixed with an appropriate amount of an organic binder to produce a granulated powder. Subsequently, after the granulated powder was filled in a mold, it was pressure molded at a pressure of 2 MPa using a pressure molding machine. In this way, two plate-shaped molded bodies having a predetermined molded body density were produced.
[0050]
Next, the two molded bodies described above were heated and held at a temperature of 600 ° C. in an inert gas atmosphere to remove (degrease) the organic binder. The degreased molded body was heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and the molded body maintained in this heated state was impregnated with molten silicon. Two SiC-based reaction sintered bodies were obtained by reaction-sintering the molded body in this molten silicon impregnation step.
[0051]
The joint surfaces of the obtained two SiC-based reaction sintered bodies were subjected to an acid (hydrofluoric acid) treatment to remove Si on the joint surfaces. Next, the bonding surfaces of these two SiC-based reaction sintered bodies were bonded with an organic adhesive. This adhesive was heated and held at a temperature of 100 to 700 ° C. in an inert gas atmosphere to make the organic adhesive a porous body mainly composed of carbon (porosity = 30 to 60%). A pre-joined body in which two SiC-based reaction sintered bodies are connected with this porous body is heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and a joined body that maintains this heated state is obtained. Molten silicon was impregnated.
[0052]
In this molten silicon impregnation step, a joined body was obtained by joining two SiC-based reaction sintered bodies with a reaction sintered joining layer. A plurality of such joined bodies were produced under different manufacturing conditions. When the microstructure of the reaction-sintered bonding layer of the obtained bonded body was observed with an electron microscope, the bonding layer was formed by reacting porous carbon and molten silicon with SiC crystal grains and a network in the gap between them. It was confirmed that it was composed of a free Si phase continuously present in the shape.
[0053]
In each bonded body described above, the average crystal grain size of the SiC crystal grains in the reaction sintered bonding layer is 0.5 to 20 μm, the porosity is 0.5 to 3%, the Si content is 10 to 40% by volume, and the average thickness is 10 to 10%. It was 120 μm. After polishing the surfaces of these joined bodies, they were subjected to characteristic evaluation described later.
[0054]
Comparative Example 1
Two molded bodies produced in the same manner as in Example 1 were naturally dried, and then heated and held at a temperature of 600 ° C. in an inert gas atmosphere to remove (degrease) the organic binder. After fixing the metal Si foil sandwiched between these two molded bodies and fixing them, they were heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere while maintaining this heating state. Molten silicon was impregnated.
[0055]
In this molten silicon impregnation step, the two compacts were each subjected to reaction sintering to obtain a SiC-based reaction sintered body, and a joined body in which these two SiC-based reaction sintered bodies were joined was obtained. A plurality of such joined bodies were produced. In the obtained joined body, it was confirmed that two SiC group reaction sintered compacts were joined by Si phase. After polishing the surfaces of these joined bodies, they were subjected to characteristic evaluation described later.
[0056]
Comparative Example 2
Two molded bodies produced in the same manner as in Example 1 were air-dried and fixed by sandwiching polycarbosilane (organosilicon resin) between the molded bodies, and then in an inert gas atmosphere. The organic binder was removed by heating and holding at a temperature of 1000 ° C. Here, the bonded portion was a porous body mainly composed of SiC. The two molded bodies bonded with this SiC porous body were heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and impregnated with molten silicon while maintaining this heating state.
[0057]
In this molten silicon impregnation step, the two compacts were each subjected to reaction sintering to obtain a SiC-based reaction sintered body, and a joined body in which these two SiC-based reaction sintered bodies were joined was obtained. A plurality of such joined bodies were produced. In the obtained joined body, it was confirmed that the two SiC-based reaction sintered bodies were joined by a SiC porous body filled with Si. After polishing the surfaces of these joined bodies, they were subjected to characteristic evaluation described later.
[0058]
Comparative Example 3
Two molded bodies produced in the same manner as in Example 1 were naturally dried and then heated and held at a temperature of 500 ° C. in an inert gas atmosphere to remove the organic binder. Next, each molded body was heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and melted silicon was impregnated and reaction-sintered while maintaining this heated state.
[0059]
A slurry made of oxide ceramic raw material powder was applied to the joining surface of the two obtained SiC-based reaction sintered bodies, and the SiC-based reaction sintered bodies were bonded and fixed to each other through this coating layer. In this state, heating was performed at 1000 ° C. while pressurizing, and the oxide ceramics on the joint surfaces were sintered and joined. A plurality of such joined bodies were produced. In the obtained joined body, it was confirmed that the two SiC-based reaction sintered bodies were joined via the oxide ceramic layer. After polishing the surfaces of these joined bodies, they were subjected to characteristic evaluation described later.
[0060]
The mechanical characteristics and thermal characteristics of the joined bodies of the SiC-based reaction sintered bodies according to Examples 1-2 and Comparative Examples 1-3 described above were measured as follows. That is, first, a bending test piece having a width of 4 mm, a thickness of 3 mm, and a length of 40 mm was processed from each joined body. At this time, the bonding surface was perpendicular to the longitudinal direction of the test piece, and the bonding layer was positioned at the center of the test piece. Using this bending test piece, a three-point bending test (room temperature) was performed under the conditions of a span of 30 mm and a head speed of 0.5 mm / min. The results are shown in Table 1 and FIG. In addition, the measurement result of a bending test shows the maximum value and the minimum value in the joined body of each example.
[0061]
Furthermore, a thermal conductivity measurement test piece having a diameter of 10 mm and a thickness of 2 mm was processed from each joined body. At this time, the joining surface was parallel to a surface having a diameter of 10 mm, and the joining layer was positioned at the center of the test piece. Using such a thermal conductivity measurement test piece, the thermal conductivity was measured at room temperature according to the thermal diffusivity, specific heat capacity, and thermal conductivity test method (JIS R 1611) of fine ceramics by the laser flash method. . The results are shown in Table 1 and FIG. In addition, the measurement result of thermal conductivity shows the maximum value and the minimum value in the joined body of each example.
[0062]
[Table 1]

[0063]
As is apparent from Table 1, FIG. 6 and FIG. 7, the joined bodies produced by the joining methods of Example 1 and Example 2 vary in bending strength values, but compared to the joined bodies according to Comparative Examples 1-3. It can be seen that the value of the bending strength is greatly improved. Moreover, while the joined body produced by the joining method of Example 1 and Example 2 shows high thermal conductivity equivalent to the base material, the joined bodies according to Comparative Examples 1 to 3 have thermal conductivity. It turns out that it falls significantly in a junction part. In addition, it is thought that the dispersion | variation in the bending strength value in Example 1 and Example 2 has influenced the state of the microstructure in a joining layer. In the following examples, the results of examining the relationship between the microstructure of the bonding layer and the bending strength will be described.
[0064]
Examples 3-7, Comparative Examples 4-5
Silicon carbide (α-SiC) powder having an average particle diameter of 2 μm and carbon powder (carbon black) having an average particle diameter of 0.5 μm were mixed so as to have a mass ratio of 10: 3 (= SiC: C). . Furthermore, this mixed powder was mixed with an appropriate amount of an organic binder, and then dispersed in a solvent to prepare a slurry. Next, the slurry was filled into the mold while being pressurized at a pressure of 0.5 MPa using a pressure casting molding machine. In this manner, a plate-shaped molded body having a predetermined molded body density was produced.
[0065]
Next, after the above plate-shaped molded body was naturally dried, the two plate-shaped molded bodies were bonded with an organic adhesive. This adhesive was heated and held at a temperature of 100 to 600 ° C. in an inert gas atmosphere to degrease the organic binder, and the organic adhesive layer was a porous body mainly composed of carbon. At this time, a plurality of samples having different adhesive layer thicknesses were prepared by adjusting the concentration of the organic adhesive and the application method. These pre-bonded bodies were heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and the molded body and the bonding layer (porous body) maintained in this heated state were impregnated with molten silicon.
[0066]
In the molten silicon impregnation step, each of the two plate-shaped compacts is subjected to reaction sintering to form a SiC-based reaction sintered body, and at the same time, these SiC-based reaction sintered bodies are joined together by a reaction sintered joining layer. Got. About each obtained joined body, the average crystal grain diameter of the SiC crystal grain which comprises the reaction sintering joining layer was measured. Further, the bending strength of each joined body was measured in the same manner as in Example 1. The results are shown in Table 2 and FIG. In addition, the comparative example in Table 2 made the average crystal grain diameter of the reaction sintered SiC crystal grain out of the scope of the present invention, and is shown for comparison with the present invention.
[0067]
[Table 2]

[0068]
As is apparent from Table 2 and FIG. 8, a bonded body having excellent strength can be obtained when the average crystal grain size of the SiC crystal grains constituting the reactive sintered bonding layer is controlled in the range of 1 to 30 μm. I understand. In these bonding layers, a Si phase having a network structure was continuously present in the gaps between the reaction sintered SiC crystal grains. The relationship between the average crystal grain size and the strength of the reaction sintered SiC crystal grains showed the same tendency even when the SiC-based reaction sintered body was bonded and then impregnated with molten silicon.
[0069]
Examples 8-14
Silicon carbide (α-SiC) powder having an average particle diameter of 1.2 μm and carbon powder (carbon black) having an average particle diameter of 0.05 μm are mixed so that the mass ratio is 10: 5 (= SiC: C). did. Furthermore, this mixed powder was mixed with an appropriate amount of an organic binder, and then dispersed in a solvent to prepare a slurry. Next, the slurry was filled into the mold while being pressurized at a pressure of 2 MPa using a pressure casting molding machine. In this manner, a plate-shaped molded body having a predetermined molded body density was produced.
[0070]
Next, after the above plate-shaped molded body was naturally dried, the two plate-shaped molded bodies were bonded with an organic adhesive. This adhesive was heated and held at 400 ° C. in an inert gas atmosphere to degrease the organic binder, and the organic adhesive layer was a porous body mainly composed of carbon. At this time, a plurality of samples having different adhesive layer thicknesses were prepared by adjusting the concentration of the organic adhesive and the application method. These pre-bonded bodies were heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and the molded body and the bonding layer (porous body) maintained in this heated state were impregnated with molten silicon.
[0071]
In the molten silicon impregnation step, each of the two plate-shaped compacts is subjected to reaction sintering to form a SiC-based reaction sintered body, and at the same time, these SiC-based reaction sintered bodies are joined together by a reaction sintered joining layer. Got. About each obtained joined body, the average thickness of the reaction sintering joining layer was measured. Further, the bending strength of each joined body was measured in the same manner as in Example 1. The results are shown in Table 3 and FIG.
[0072]
[Table 3]

[0073]
As is apparent from Table 3 and FIG. 9, it can be seen that when the thickness of the reactive sintered bonding layer is in the range of 1 to 200 μm, a bonded body having excellent strength can be obtained with good reproducibility. In addition, these joining layers were comprised from the reaction-sintered SiC crystal grain and the Si phase of the network structure which exists in the clearance gap. The relationship between the thickness and strength of the reaction sintered bonding layer showed the same tendency even when the SiC-based reaction sintered body was bonded and then impregnated with molten silicon.
[0074]
Examples 15-18
Silicon carbide (α-SiC) powder having an average particle diameter of 5 μm and carbon powder (carbon black) having an average particle diameter of 0.5 μm were mixed so as to have a mass ratio of 10: 4 (= SiC: C). . Furthermore, this mixed powder was mixed with an appropriate amount of an organic binder, and then dispersed in a solvent to prepare a slurry. Next, the slurry was filled into the mold while being pressurized at a pressure of 1.5 MPa using a pressure casting molding machine. In this manner, a plate-shaped molded body having a predetermined molded body density was produced.
[0075]
Next, after the above plate-shaped molded body was naturally dried, the two plate-shaped molded bodies were bonded with an organic adhesive. This adhesive was heated and held at a temperature of 100 to 600 ° C. in an inert gas atmosphere to degrease the organic binder, and the organic adhesive layer was a porous body mainly composed of carbon. At this time, a plurality of samples having different adhesive layer thicknesses were prepared by adjusting the concentration of the organic adhesive and the application method. These pre-bonded bodies were heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and the molded body and the bonding layer (porous body) maintained in this heated state were impregnated with molten silicon.
[0076]
In the molten silicon impregnation step, each of the two plate-shaped compacts is subjected to reaction sintering to form a SiC-based reaction sintered body, and at the same time, these SiC-based reaction sintered bodies are joined together by a reaction sintered joining layer. Got. About each obtained joined body, the porosity of the reaction sintering joining layer was measured. Further, the bending strength of each joined body was measured in the same manner as in Example 1. The results are shown in Table 4 and FIG.
[0077]
[Table 4]

[0078]
As can be seen from Table 4 and FIG. 10, when the porosity of the reaction sintered bonding layer is 5% or less, particularly when the porosity is 2% or less, a bonded body having excellent strength can be obtained with good reproducibility. I understand that. In addition, these joining layers were comprised from the reaction-sintered SiC crystal grain and the Si phase of the network structure which exists in the clearance gap. The relationship between the porosity and strength of the reaction sintered bonding layer showed the same tendency even when the SiC-based reaction sintered body was bonded and then impregnated with molten silicon.
[0079]
Example 19-21, Reference Examples 1-2
  Silicon carbide (α-SiC) powder having an average particle diameter of 5 μm and carbon powder (carbon black) having an average particle diameter of 1 μm were mixed so as to have a mass ratio of 10: 2 (= SiC: C). Furthermore, this mixed powder was mixed with an appropriate amount of an organic binder, and then dispersed in a solvent to prepare a slurry. Next, the slurry was filled into the mold while being pressurized at a pressure of 5 MPa using a pressure casting molding machine. In this manner, a plate-shaped molded body having a predetermined molded body density was produced.
[0080]
Next, after the above plate-shaped molded body was naturally dried, the two plate-shaped molded bodies were bonded with an organic adhesive. This adhesive was heated and held at 400 ° C. in an inert gas atmosphere to degrease the organic binder, and the organic adhesive layer was a porous body mainly composed of carbon. At this time, by adjusting the concentration of the organic adhesive, a plurality of samples having different application concentrations of the adhesive were produced. These pre-bonded bodies were heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and the molded body and the bonding layer (porous body) maintained in this heated state were impregnated with molten silicon.
[0081]
In the molten silicon impregnation step, each of the two plate-shaped compacts is subjected to reaction sintering to form a SiC-based reaction sintered body, and at the same time, these SiC-based reaction sintered bodies are joined together by a reaction sintered joining layer. Got. About each obtained joined body, Si content of the reaction sintering joining layer was measured. Further, the bending strength of each joined body was measured in the same manner as in Example 1. The results are shown in Table 5 and FIG.
[0082]
[Table 5]

[0083]
As is apparent from Table 5 and FIG. 11, it can be seen that when the Si content of the reactive sintered bonding layer is 5 to 50% by volume, a bonded body having excellent strength can be obtained with good reproducibility. In addition, these joining layers were comprised from the reaction-sintered SiC crystal grain and the Si phase of the network structure which exists in the clearance gap. The relationship between the Si content and the strength of the reaction-sintered bonding layer showed the same tendency even when the SiC-based reaction sintered body was bonded and then impregnated with molten silicon.
[0084]
Example22~23
  Silicon carbide (α-SiC) powder having an average particle diameter of 0.5 μm and carbon powder (carbon black) having an average particle diameter of 0.01 μm are set to 10: 3 (= SiC: C) in mass ratio. Mixed. Furthermore, this mixed powder was mixed with an appropriate amount of an organic binder, and then dispersed in a solvent to prepare a slurry. Next, the slurry was filled into the mold while being pressurized at a pressure of 1 MPa using a pressure casting molding machine. In this manner, a plate-shaped molded body having a predetermined molded body density was produced.
[0085]
Next, after the above plate-shaped molded body was naturally dried, the two plate-shaped molded bodies were bonded with an organic adhesive. This adhesive was heated and held at a temperature of 100 to 700 ° C. in an inert gas atmosphere to degrease the organic binder and to make the organic adhesive layer a porous body mainly composed of carbon. At this time, samples having different pore diameter distributions were prepared by adjusting the temperature rising rate in the heat treatment using the organic adhesive layer as a porous body mainly composed of carbon. These pre-bonded bodies were heated to a temperature of 1400 ° C. or higher under reduced pressure or in an inert gas atmosphere, and the molded body and the bonding layer (porous body) maintained in this heated state were impregnated with molten silicon.
[0086]
  In the molten silicon impregnation step, each of the two plate-shaped compacts is subjected to reaction sintering to form a SiC-based reaction sintered body, and at the same time, these SiC-based reaction sintered bodies are joined with a reaction-sintered joining layer. Got. In this way, a joined body having a three-layer joining layer (Example22) And one-layer structure (Example)23). The microstructure of the reaction sintered bonding layer was identified by observing with a metal microscope. Further, the bending strength of each joined body was measured in the same manner as in Example 1. The results are shown in Table 6 and FIG.
[0087]
[Table 6]

[0088]
As is apparent from Table 6 and FIG. 12, when a reaction sintered bonding layer having a three-layer structure is provided, a bonded body having superior strength can be obtained with good reproducibility, and the durability and reliability of the bonded body are improved. be able to. The relationship between the structure and strength of the reaction sintered bonding layer showed the same tendency even when the SiC-based reaction sintered body was bonded and impregnated with molten silicon.
[0089]
Example24~30
  Example above22In Example, except that a plurality of samples having different pore size distributions were prepared by adjusting the heating rate in the heat treatment.22The joined bodies were produced in the same manner as described above. In each of these joined bodies, the average thickness of the central layer in the reaction sintered joining layer having a three-layer structure was measured. Further, the bending strength of each joined body was measured in the same manner as in Example 1. The results are shown in Table 7 and FIG.
[0090]
[Table 7]

[0091]
As is apparent from Table 7 and FIG. 13, when the thickness of the central layer in the reaction-sintered bonding layer having a three-layer structure is in the range of 0.5 to 100 μm, a bonded body having superior strength can be obtained with good reproducibility. The durability and reliability of the joined body can be increased. The relationship between the structure and strength of the reaction sintered bonding layer showed the same tendency even when the SiC-based reaction sintered body was bonded and impregnated with molten silicon.
[0092]
Example31~37
  Example above22In Example, except that a plurality of samples having different pore size distributions were prepared by adjusting the heating rate in the heat treatment.22The joined bodies were produced in the same manner as described above. In each of these joined bodies, each Si content of the central layer and the side layer in the reaction sintered joining layer having a three-layer structure was measured. Moreover, Si content ratio calculated | required with respect to the center layer of these side surfaces layers was calculated | required. Further, the bending strength of each joined body was measured in the same manner as in Example 1. The results are shown in Table 8 and FIG.
[0093]
[Table 8]

[0094]
As is apparent from Table 8 and FIG. 14, when the Si content ratio of each side layer with respect to the central layer is 10 to 70% higher, a bonded body having superior strength can be obtained with good reproducibility, and the durability of the bonded body And can improve reliability. The relationship between the structure and strength of the reaction sintered bonding layer showed the same tendency even when the SiC-based reaction sintered body was bonded and impregnated with molten silicon.
[0095]
【The invention's effect】
As described above, according to the silicon carbide-based bonded component of the present invention, the bonding strength between a plurality of component units made of a SiC-based reactive sintered body can be increased with good reproducibility. Accordingly, it is possible to stably provide silicon carbide based bonded parts having excellent strength, durability, reliability, and the like, particularly large structures and complex shaped parts. In addition, according to the method for manufacturing a silicon carbide-based bonded component of the present invention, a plurality of component units made of a SiC-based reaction sintered body can be bonded with high strength. It can be produced efficiently and at low cost.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic structure of a silicon carbide based bonded part according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view schematically showing a microstructure of a bonding layer portion of the silicon carbide based bonded component shown in FIG.
3 is a cross-sectional view schematically showing a layer structure of a bonding layer of the silicon carbide based bonded component shown in FIG. 1. FIG.
FIG. 4 is a cross-sectional view showing a process for manufacturing a silicon carbide based bonded part according to the first manufacturing method of the present invention.
FIG. 5 is a cross-sectional view showing a manufacturing process of a silicon carbide based bonded part according to a second manufacturing method of the present invention.
FIG. 6 is a diagram showing the measurement result of the bending strength of the silicon carbide based bonded part according to the example of the present invention together with the measurement result of the comparative example.
FIG. 7 is a diagram showing the measurement result of the thermal conductivity of the silicon carbide based bonded part according to the example of the present invention together with the measurement result of the comparative example.
FIG. 8 is a diagram showing the relationship between the average crystal grain size of silicon carbide crystal grains and the bending strength in the bonding layer of the silicon carbide-based bonded component according to the example of the present invention.
FIG. 9 is a diagram showing the relationship between the thickness of the bonding layer and the bending strength of the silicon carbide-based bonded component according to the embodiment of the present invention.
FIG. 10 is a diagram showing the relationship between the porosity of the bonding layer and the bending strength of the silicon carbide-based bonded component according to the example of the present invention.
FIG. 11 is a diagram showing the relationship between the silicon content of the bonding layer and the bending strength of the silicon carbide-based bonded component according to the example of the present invention.
FIG. 12 is a diagram showing the relationship between the layer structure of the bonding layer and the bending strength of the silicon carbide-based bonded component according to the example of the present invention.
FIG. 13 is a diagram showing the relationship between the thickness of the center layer and the bending strength in the three-layer structure bonding layer of the silicon carbide based bonded component according to the example of the present invention.
FIG. 14 is a view showing the relationship between the silicon content ratio thickness and the bending strength in the three-layer structure bonding layer of the silicon carbide-based bonding component according to the example of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Silicon carbide group joining components, 2, 3 ... Parts unit which consists of silicon carbide group reaction sintered body, 4 ... Reaction sintering joining layer, 5 ... Silicon carbide crystal grain, 6 ... Free silicon phase, 21 ... Molded body, 22 ... Organic adhesive layer, 25,28 ... Silicon carbide based reaction sintered body, 26 ... Joint body

Claims (8)

In a silicon carbide based bonded component formed by bonding a plurality of component units made of a silicon carbide based reaction sintered body via a bonding layer,
The bonding layer is mainly composed of silicon carbide crystal grains having an average crystal grain size in the range of 0.1 to 30 μm, and a silicon phase continuously present in a network form in the gaps between the silicon carbide crystal grains, And the silicon carbide based joining component characterized by containing the said silicon phase in 5-50 volume%. The silicon carbide based bonded component according to claim 1,
A silicon carbide based bonded part, wherein the bonding layer has a thickness in the range of 1 to 200 μm. In the silicon carbide based bonded part according to claim 1 or 2,
A silicon carbide based bonded part, wherein the bonding layer has a porosity of 5% or less. In the silicon carbide based bonded part according to any one of claims 1 to 3 ,
An average bending strength of the joined part is 150 MPa or more and 1000 MPa or less. In manufacturing a silicon carbide based bonded component by bonding a plurality of component units made of a silicon carbide based reactive sintered body,
Producing a plurality of molded bodies corresponding to the plurality of component units;
Bonding the plurality of molded bodies with an organic adhesive;
A step of bonding the plurality of molded bodies and then heat-treating the bonded portion with the organic adhesive into a porous body having a porosity mainly composed of carbon of 20 to 70%;
The plurality of molded bodies including the bonding portion formed as the porous body are impregnated with molten silicon, and the plurality of molded bodies are each subjected to reaction sintering to form the plurality of component units, and the plurality of components. Between the units, silicon carbide crystal grains having an average crystal grain size in the range of 0.1 to 30 μm and silicon in a range of 5 to 50% by volume existing continuously in a network between the silicon carbide crystal grains. And a step of integrally bonding with a bonding layer mainly composed of a phase. In the manufacturing method of the silicon carbide based joining component of Claim 5 ,
In the silicon impregnation step, the melted silicon is impregnated under reduced pressure or in an inert atmosphere while heating the plurality of bonded compacts to a temperature of 1400 ° C. or higher. A method for producing a silicon carbide based bonded part. In manufacturing a silicon carbide based bonded component by bonding a plurality of component units made of a silicon carbide based reactive sintered body,
Removing each silicon present on the joint surfaces of the plurality of component units made of the silicon carbide based reaction sintered body;
Adhering between bonding surfaces of the plurality of component units with an organic adhesive;
A step of bonding the plurality of component units and then heat-treating the bonded portion with the organic adhesive into a porous body having a porosity mainly composed of carbon of 20 to 70%;
The silicon carbide crystal grains having an average crystal grain size in the range of 0.1 to 30 μm and the silicon carbide crystal grains produced by impregnating the melted silicon into the porous bonded portion and reacting between the plurality of component units. And a step of integrally bonding with a bonding layer mainly composed of a silicon phase in a range of 5 to 50% by volume present continuously in a network in the gap of Production method. The method of manufacturing a silicon carbide based cemented part according to claim 7 Symbol mounting,
In the silicon impregnation step, the bonded portions are impregnated with the molten silicon under reduced pressure or in an inert atmosphere while heating the plurality of bonded sintered bodies to a temperature of 1400 ° C. or higher. A method for manufacturing a silicon carbide based bonded part.

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