JP2004339536A

JP2004339536A - Method of producing copper based low thermal expansion highly heat conductive member

Info

Publication number: JP2004339536A
Application number: JP2003134305A
Authority: JP
Inventors: Zenzo Ishijima; 善三石島
Original assignee: Hitachi Powdered Metals Co Ltd
Current assignee: Resonac Corp
Priority date: 2003-05-13
Filing date: 2003-05-13
Publication date: 2004-12-02
Anticipated expiration: 2023-05-13
Also published as: JP3883985B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily producing a sintered material in which an Invar alloy is dispersed into a copper based matrix, in providing a material which has more satisfactory dimensional precision and excellent workability and can be plated with nickel without using expensive materials such as molybdenum and tungsten as in the prior art, in a copper based alloy material for a member requiring a low thermal expansion coefficient and high heat dissipation properties such as a heat sink. <P>SOLUTION: A powdery mixture obtained by mixing, to copper powder, 5 to 60 mass% iron based alloy powder whose thermal expansion coefficient up to 100°C is ≤6×10<SP>-6</SP>/K is subjected to compression molding to ≥93% relative density, and is thereafter sintered at 400 to 600°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、Ｓｉチップやセラミックス基板等と同等の熱膨張係数とともに、高い放熱性が要求されるヒートシンクに好適な銅基低熱膨張高熱伝導部材の製造方法に関する。
【０００２】
【従来の技術】
ヒートシンク等の低い熱膨張係数と、高い放熱性が要求される部材には、銅−モリブデン系、銅−タングステン系の材料が用いられている。
これらの材料は銅の高い熱伝導率と、モリブデンやタングステンの低い熱膨張率を兼ね備えさせることを目的としたもので、例えば特開昭６２−２８４０３２号公報では、銅粉末とモリブデン粉末との混合粉末を圧粉成形した後、銅の液相が発生する温度で液相焼結して、銅マトリックスにモリブデン相が分散する組織の材料とすることが開示されている。また、特開昭５９−２１０３２号公報には、モリブデンまたはタングステンの粉末を高温で焼結してスケルトンを構成した後、銅溶浸を施して、モリブデンまたはタングステンのスケルトン中に銅が分散した材料が開示されている。
【０００３】
また、一方で、熱伝導性が高い銅に、熱膨張係数が小さく不変鋼とも呼ばれるインバー合金やスーパーインバー合金を分散させた材料が特開平２−２１３４５２号公報や特開平９−１３１０２号公報等で開示されている。
【０００４】
【特許文献１】
特開昭６２−２８４０３２号公報
【特許文献２】
特開昭５９−２１０３２号公報
【特許文献３】
特開平２−２１３４５２号公報
【特許文献４】
特開平９−１３１０２号公報
【０００５】
【発明が解決しようとする課題】
しかし、上記特許文献１、２のような材料は、原料とするモリブデン粉末やタングステン粉末が高価であるため、材料費自体が嵩むことが大きな問題である。また、前者の場合には、液相焼結するため、変形しやすく、寸法バラツキが大きいため、焼結後に、加工が必要であるが、モリブデンは硬く、加工性が低いという欠点を有しており、このような相が分散する材料も加工性は低いという問題を有している。また、後者の場合は、スケルトンの全ての隙間に銅を溶浸することが難しいため、熱伝導性が劣るとともに品質にバラツキが生じやすく、また予め高温焼結した後、銅を溶浸するため工程費が嵩むものである。さらに、加工性の問題については前者と同様である。
【０００６】
さらに両者に共通であるが、ヒートシンクはハンダ付けのためニッケルメッキが施される場合があるが、機械加工後、モリブデンやタングステンが露出するためニッケルメッキを施し難いという欠点も有する。
【０００７】
また、上記特許文献３には、焼結温度が８００℃以上であることが記載され、上記特許文献４には、７５０℃以上で焼結した場合にインバー成分がＣｕ中に拡散して熱伝導性が劣化するため、インバー合金粉末表面に拡散防止被膜を設けることを骨子としており、インバー合金粉末と銅粉末の焼結が難しいことを示している。
【０００８】
本発明は、モリブデンやタングステンのような高価な材料を使用せずに、寸法精度がよく、加工性に優れ、さらに、ニッケルメッキが可能な高熱伝導部材を提供するにあたり、銅系マトリックス中にインバー合金が分散する焼結材料の簡便な改良された製造方法を提供することにある。
【０００９】
【課題を解決するための手段】
本発明の銅基低熱膨張高熱伝導部材の製造方法は、銅粉末に、１００℃までの熱膨張係数が６×１０^−６／Ｋ以下の鉄基合金粉末を、質量比で５〜６０％を添加し、混合した混合粉末を用い、相対密度で９３％以上に圧縮成形した後、４００〜６００℃で焼結することを特徴とする。
また、前記銅粉末が、−１００メッシュの粉末で、かつ粒径５０μｍ以上の粉末の含有量が６０％以下の粉末であるとともに、前記鉄基合金粉末が、−１００メッシュで、かつ、粒径５０μｍ以下の粉末の含有量が６０％以下の粉末であることを特徴とする。
【００１０】
【発明の実施の形態】
本発明は、１００℃までの熱膨張係数が６×１０^−６／Ｋ以下の鉄基合金粉末が分散するとともに、鉄基合金粉末表面が僅に、マトリックスと拡散して強固に結合した金属組織を呈する銅基低熱膨張高熱伝導部材を製造することを目的とする。
【００１１】
このような銅マトリックスと鉄基合金粉末の拡散状態を形成するために、焼結は４００〜６００℃の温度範囲で行う必要がある。すなわち、焼結温度が４００℃より低いと銅マトリックス自体が十分に拡散されず、熱伝導性および強度が劣ることになり、６００℃を越えると鉄基合金粉末が銅マトリックス中に必要以上に拡散して、熱膨張の抑制機能および銅マトリックスの熱伝導率が低下することとなる。特に、鉄基合金粉末として、ニッケルを含む鉄基合金を用いる場合、銅とニッケルは全率固溶であるので、ニッケルの銅マトリックスへの拡散が著しくなり、これらの不具合の度合が大きい。
【００１２】
また、鉄基合金粉末のマトリックスへの拡散を抑制することを目的とした４００〜６００℃の焼結温度では、ほとんど緻密化しない。このため、マトリックスの熱伝導率を高くするためには、予め相対密度で９３％以上に圧縮成形しておく必要がある。一方で、銅の液相が発生しないため、寸法精度も優れるという利点も有する。
【００１３】
上記の１００℃までの熱膨張係数が６×１０^−６／Ｋ以下の鉄基合金としては、インバー（Ｆｅ−３６Ｎｉ）、スーパーインバー（Ｆｅ−３１Ｎｉ−５Ｃｏ）、ステンレスインバー（Ｆｅ−５２．３Ｃｏ−１０．４Ｃｒ）、コバール（Ｆｅ−２９Ｎｉ−１７Ｃｏ）、４２アロイ（Ｆｅ−４２Ｎｉ）等の合金や、Ｆｅ−１７Ｂ合金等がある。これらの合金は上記のモリブデンやタングステンに比べて安価であり、加工性にも優れたものである。
【００１４】
上記の鉄基合金粉末は、マトリックス中の分散量が多くなるにしたがい、熱膨張抑制の効果が大きくなるが、マトリックスの量の減少にしたがい、熱伝導性は低下する。鉄基合金粉末は、質量比で５％未満であると、熱膨張抑制の効果が乏しく、６０％を越えるとマトリックスが少なくなり、マトリックスのＣｕの連続性が著しく低下するため熱伝導性が低下する。また、前記のような１００℃までの熱膨張係数が６×１０^−６／Ｋ以下の鉄基合金どうしは、上記温度範囲ではほとんど焼結しないため結合性が低く、一層熱伝導性が低下することとなる。以上より、鉄基合金粉末の添加量は、５〜６０％の範囲にする必要がある。
【００１５】
このような低熱膨張高熱伝導複合部材は、銅粉末に、上記鉄基合金粉末を、質量比で５〜６０％を添加混合した混合粉末を用いて、圧縮成形した後、上記温度で焼結することで容易に製造することができる。
【００１６】
上記のようなマトリックスを構成する銅粉末は微粉末を用いることによりネック形成部を増加させ拡散を進行させることができる。さらに、銅粉末の粒度分布を鉄基合金粉末の粒度分布より細かくすることによって、マトリックスである銅の連続性は高まり、熱伝導性を向上させることができる。このことを前提とした上で、全体の粒度が細かくなりすぎると、粉末の流動性の低下や型かじり等の不具合が発生するだけでなく、鉄基合金粉末のネック形成部が増加することにより、マトリックスへの拡散量が多くなり、マトリックスの熱伝導性の低下や、鉄基合金粉末の成分組成が変化することによる熱膨張抑制作用の低下が生じる。一方、全体の粒径が逆に大きくなりすぎると、マトリックス中に均一に分散できなくなるため、局部的に熱膨張抑制の効果が弱まる箇所が生じ、効果的に熱膨張を抑制できなくなる。
【００１７】
これらのことから鉄基合金粉末として、−１００メッシュ（１００メッシュ篩通過）のものが好ましく、かつ、粒径５０μｍ以下の粉末の含有量が６０％以下の粉末を用いることが一層好ましい。粒度構成として、５０μｍ以下の粉末が６０％を越えるような鉄基合金粉末は、微粉の量が多く、熱伝導性が低くなる。また、マトリックス用の銅粉末としては、上記鉄基合金粉末よりも粒度が小さくなるように、−１００メッシュの粉末で、かつ粒径５０μｍ以上の粉末の含有量が６０％以下の粉末を用いることが好ましい。このように鉄基合金粉末とマトリックス粉末の粒度を調整することによって、より一層の効率的な熱伝導と熱膨張抑制の作用が得られる。
【００１８】
【実施例】
＜実施例１＞
（鉄基合金粉末の熱膨張係数、添加量、焼結温度の影響）
表１に示す１００℃までの熱膨張係数の値を有し、５０μｍ以下の粉末を４０％含有するような粒度構成に調整した−１００メッシュの鉄基合金粉末を用意した。
【００１９】
【表１】

【００２０】
−１００メッシュで粒径５０μｍ以上の粉末を４０％含有するように調整した銅粉末に、これらの鉄基合金粉末を、表２に示す配合割合で添加し、１４７０ＭＰａで圧粉成形した後、アンモニア分解ガス雰囲気中、表２に示す温度で焼結を行い試料番号０１〜３１の試料を作製した。これらの試料につき、熱伝導率と、熱膨張係数について測定した結果を表２に併せて示す。また表２の測定結果について、グラフ化したものを図１〜４に示す。
【００２１】
【表２】

【００２２】
表２の試料番号０１〜０９は銅粉末に対して鉄基合金粉末（Ｆｅ−３６Ｎｉ）の添加量を変えたものである。これらの試料を比較することによって、鉄基合金粉末の添加量が熱伝導率と熱膨張係数に及ぼす影響がわかる。これをグラフ化したのが図１である。これらより、鉄基合金粉末の添加量が５質量％の試料０２は、無添加（銅１００％）の試料０１に比べて、熱伝導率および熱膨張係数が小さい値を示し、熱膨張係数が改善されていることがわかる。
また、鉄基合金粉末の添加量が増加するにしたがって熱伝導率および熱膨張係数は低下する傾向を示すことがわかる。しかし、鉄基合金粉末の添加量が６０質量％を越える試料０９では、熱膨張係数が逆に増加している。これは、５００℃の焼結温度では焼結により結合していない鉄基合金粉末が多く、銅の膨張を抑制しきれないで熱膨張係数が増加傾向に転じたものと考えられる。すなわち、銅粉末と接触している鉄基合金粉末は表層で結合しているが、鉄基合金粉末どうしは結合していないため、銅の熱膨張に際して、結合していない鉄基合金粉末どうしの界面でずれが生じて熱膨張抑制の効果が得られなかったと考える。
【００２３】
また、試料番号１０〜１４、１５〜１９、２０〜２４は鉄基合金粉末（Ｆｅ−３６Ｎｉ−５Ｃｏ）の添加量がそれぞれ３０質量％、４０質量％および５０質量％において、焼結温度を変えたものである。これらの試料を比較することにより、焼結温度が熱伝導率と熱膨張係数に及ぼす影響がわかる。これをグラフ化したものが図２および図３である。これらより、焼結温度が上昇するとともに、熱伝導率は４００℃、５００℃から６００℃にかけて低下する傾向を示し、１０００℃では、著しく低下することがわかる。一方、熱膨張係数は、４００から５００℃で低下した後、それ以上の温度で増加する傾向を示し、１０００℃では著しい増加を示すことがわかる。これは、１０００℃の焼結温度では、銅粉末と鉄基合金粉末どうしが拡散し、特性が劣化したためと考える。なお、焼結温度３００℃では、マトリックスの焼結が進行しておらず、強度が乏しいものであった。以上の傾向は鉄基合金粉末の添加量に依らずいずれも同様の傾向を示しており、これらのことから、焼結温度は４００〜６００℃の範囲の範囲が適切であることがわかる。
【００２４】
さらに、試料番号０６、１７、２６、２９、３１は組成の異なる鉄基合金粉末を４０質量％添加し、５００℃で焼結したものである。これらの試料を比較することにより鉄基合金粉末の種類が熱伝導率と熱膨張係数に及ぼす影響がわかる。これをグラフ化したものが図４である。これらのいずれの試料においても１００℃までの熱膨張係数が６×１０^−６／Ｋ以下の鉄基合金粉末であると鉄基合金粉末の種類による熱伝導率の変化はほとんどなく、かつ熱膨張係数は小さく抑制されていることがわかる。
【００２５】
以上より、銅マトリックス中に、１００℃までの熱膨張係数が６×１０^−６／Ｋ以下の鉄基合金粉末が、質量比で、５〜６０％分散し、４００〜６００℃で焼結した試料は熱伝導率が著しく低下することなく、かつ熱膨張係数は小さいことが確認された。
【００２６】
＜実施例２＞
（粒度構成の影響）
−１００メッシュの銅粉末と、鉄基合金粉末として−１００メッシュのＦｅ−３６Ｎｉ粉末を用い、表３の試料番号０６、３２〜３９に示す割合のものを１４７０ＭＰａで圧粉成形した後、アンモニア分解ガス雰囲気中、５００℃で焼結を行った。これらの試料につき、熱伝導率と、熱膨張係数について測定した結果を表３に併せて示す。
【００２７】
【表３】

【００２８】
試料番号０６、３２〜３６は、５０μｍ以上の粉末の量が６０％の銅粉末に対して、５０μｍ以下の粉末の量の異なる鉄基合金粉末を配合したものである。これらを比較することで、鉄基合金粉末の５０μｍ以下の粉末の含有量の熱膨張係数および熱伝導率への影響がわかる。表３より、熱膨張係数は一定であるが、鉄基合金粉末の５０μｍ以下の粉末の量が減少するにつれ熱伝導率は向上していることがわかる。特に、５０μｍ以下の粉末が６０％以下の試料では熱伝導率が１００Ｗ／ｍ・Ｋを越える良好な値を示している。
【００２９】
試料番号０６、３７〜３９は、５０μｍ以上の粉末の量が異なる銅粉末に対して、５０μｍ以下の粉末の量が４０％の鉄基合金粉末を配合したものである。これらを比較することで、５０μｍ以上の銅粉末の含有量の違いによる熱膨張係数と熱伝導率への影響がわかる。５０μｍ以上の銅粉末の含有量が増加するにつれて、熱伝導率は低下していることがわかる。５０μｍ以上の銅粉末の量が６０％以下の試料では熱伝導率が１００Ｗ／ｍ・Ｋを越える良好な値を示している。
【００３０】
以上より、マトリックス粉末が、−１００メッシュの粉末で、かつ粒径５０μｍ以上の粉末が６０％以下の粉末であるとともに、前記鉄基合金粉末が、−１００メッシュで、かつ、粒径５０μｍ以下の粉末が６０％以下の粉末を用いると、特に効果が高いことが確認された。
【００３１】
【発明の効果】
本発明による銅基低熱膨張高熱伝導部材の製造方法によれば、簡便な工程で、銅マトリックス中に、１００℃までの熱膨張係数が６×１０^−６／Ｋ以下の鉄基合金粉末が僅かにマトリックスと拡散した金属組織を呈する、高い熱伝導性と低い熱膨張率を兼ね備えた銅基低熱膨張高熱伝導部材を製造することができる。
【図面の簡単な説明】
【図１】鉄基合金粉末の添加量と熱伝導率および熱膨張係数との関係を示すグラフである。
【図２】鉄基合金粉末の各添加量における、焼結温度と熱伝導率との関係を示すグラフである。
【図３】鉄基合金粉末の各添加量における、焼結温度と熱膨張係数との関係を示すグラフである。
【図４】鉄基合金粉末の種類と、熱伝導率および熱膨張係数との関係を示すグラフである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a copper-based low-thermal-expansion high-thermal-conductivity member suitable for a heat sink that requires a high heat dissipation as well as a thermal expansion coefficient equivalent to that of a Si chip or a ceramic substrate.
[0002]
[Prior art]
Copper-molybdenum-based and copper-tungsten-based materials are used for members requiring a low thermal expansion coefficient and high heat dissipation such as a heat sink.
The purpose of these materials is to combine the high thermal conductivity of copper with the low thermal expansion coefficient of molybdenum and tungsten. For example, Japanese Patent Application Laid-Open No. 62-284032 discloses that a mixture of copper powder and molybdenum powder is used. It is disclosed that after powder compaction, liquid phase sintering is performed at a temperature at which a liquid phase of copper is generated to obtain a material having a structure in which a molybdenum phase is dispersed in a copper matrix. JP-A-59-21032 discloses a material in which molybdenum or tungsten powder is sintered at a high temperature to form a skeleton and then copper infiltration is performed to disperse copper in the molybdenum or tungsten skeleton. Is disclosed.
[0003]
On the other hand, a material obtained by dispersing an invar alloy or a super invar alloy, which is also referred to as an invariable steel having a small coefficient of thermal expansion, in copper having high thermal conductivity is disclosed in JP-A-2-213452 and JP-A-9-13102. Are disclosed.
[0004]
[Patent Document 1]
JP 62-284032 A [Patent Document 2]
JP-A-59-21032 [Patent Document 3]
JP-A-2-213452 [Patent Document 4]
Japanese Patent Application Laid-Open No. 9-13102
[Problems to be solved by the invention]
However, in the materials described in Patent Documents 1 and 2, since a molybdenum powder or a tungsten powder as a raw material is expensive, a large problem is that the material cost itself increases. Also, in the former case, since liquid phase sintering is easy to deform and large in dimensional variation, processing is required after sintering, but molybdenum has the disadvantage that it is hard and has low workability. Therefore, materials in which such a phase is dispersed also have a problem that workability is low. Also, in the latter case, it is difficult to infiltrate copper into all the gaps of the skeleton, so the thermal conductivity is inferior and the quality tends to vary, and the copper is infiltrated after high-temperature sintering in advance. The process cost is high. Further, the problem of workability is the same as the former.
[0006]
Further, although common to both, the heat sink is sometimes plated with nickel for soldering, but has the disadvantage that it is difficult to apply nickel plating because molybdenum and tungsten are exposed after machining.
[0007]
Patent Document 3 describes that the sintering temperature is 800 ° C. or higher, and Patent Document 4 describes that when sintering is performed at 750 ° C. or higher, the invar component diffuses into Cu and heat conduction occurs. The main point is that an anti-diffusion coating is provided on the surface of the Invar alloy powder because of the deterioration of the properties, which indicates that sintering of the Invar alloy powder and the copper powder is difficult.
[0008]
The present invention provides a highly heat-conductive member having good dimensional accuracy, excellent workability, and nickel plating without using expensive materials such as molybdenum and tungsten. An object of the present invention is to provide a simple and improved method for producing a sintered material in which an alloy is dispersed.
[0009]
[Means for Solving the Problems]
The method for producing a copper-based low-thermal-expansion high-thermal-conductivity member according to the present invention is characterized in that a copper powder has an iron-based alloy powder having a thermal expansion coefficient up to 100 ° C. of 6 × 10 ⁻⁶ / K or less, Using the mixed powder added and mixed, the material is compression-molded to a relative density of 93% or more, and then sintered at 400 to 600 ° C.
In addition, the copper powder is -100 mesh powder and the content of powder having a particle size of 50 μm or more is 60% or less, and the iron-based alloy powder is -100 mesh and has a particle size of -100 mesh. It is characterized in that the content of the powder of 50 μm or less is a powder of 60% or less.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention provides a metal structure in which an iron-based alloy powder having a thermal expansion coefficient of 6 × 10 ⁻⁶ / K or less up to 100 ° C. is dispersed, and the surface of the iron-based alloy powder is slightly diffused with a matrix and firmly bonded. An object of the present invention is to produce a copper-based low-thermal-expansion high-thermal-conductivity member exhibiting the following.
[0011]
In order to form such a diffusion state of the copper matrix and the iron-based alloy powder, the sintering needs to be performed in a temperature range of 400 to 600 ° C. That is, if the sintering temperature is lower than 400 ° C., the copper matrix itself is not sufficiently diffused, resulting in poor thermal conductivity and strength. If the sintering temperature is higher than 600 ° C., the iron-based alloy powder is unnecessarily diffused into the copper matrix. As a result, the function of suppressing thermal expansion and the thermal conductivity of the copper matrix are reduced. In particular, when an iron-based alloy containing nickel is used as the iron-based alloy powder, since copper and nickel are completely dissolved, the diffusion of nickel into the copper matrix becomes remarkable, and the degree of these problems is large.
[0012]
Further, at a sintering temperature of 400 to 600 ° C. for the purpose of suppressing the diffusion of the iron-based alloy powder into the matrix, the powder is hardly densified. For this reason, in order to increase the thermal conductivity of the matrix, it is necessary to previously compress the matrix to a relative density of 93% or more. On the other hand, since a liquid phase of copper is not generated, there is also an advantage that dimensional accuracy is excellent.
[0013]
Examples of the iron-based alloy having a thermal expansion coefficient of up to 6 × 10 ⁻⁶ / K up to 100 ° C. include invar (Fe-36Ni), super invar (Fe-31Ni-5Co), and stainless invar (Fe-52.3Co). -10.4Cr), Kovar (Fe-29Ni-17Co), 42 alloy (Fe-42Ni) and the like, and Fe-17B alloy. These alloys are inexpensive as compared with the above-mentioned molybdenum and tungsten, and have excellent workability.
[0014]
The above-described iron-based alloy powder has an effect of suppressing thermal expansion as the amount of dispersion in the matrix increases, but the thermal conductivity decreases as the amount of the matrix decreases. If the mass ratio of the iron-based alloy powder is less than 5%, the effect of suppressing thermal expansion is poor, and if it exceeds 60%, the matrix is reduced, and the continuity of Cu in the matrix is significantly reduced, so that the thermal conductivity is reduced. I do. Further, iron-base alloys having a thermal expansion coefficient of 6 × 10 ⁻⁶ / K or less up to 100 ° C. hardly sinter in the above-mentioned temperature range, so that their bonding properties are low and the thermal conductivity is further reduced. It will be. As described above, the amount of the iron-based alloy powder needs to be in the range of 5 to 60%.
[0015]
Such a low-thermal-expansion high-thermal-conductivity composite member is compression-molded using a mixed powder obtained by adding 5 to 60% by mass of the iron-based alloy powder to a copper powder and then sintering at the above-described temperature. Thus, it can be easily manufactured.
[0016]
By using the fine powder of the copper powder constituting the matrix as described above, the neck forming portion can be increased and the diffusion can be advanced. Further, by making the particle size distribution of the copper powder finer than the particle size distribution of the iron-based alloy powder, the continuity of copper as a matrix is enhanced, and the thermal conductivity can be improved. On the premise of this, if the overall particle size is too fine, not only does the flowability of the powder decrease or problems such as mold galling occur, but also the neck forming portion of the iron-based alloy powder increases, In addition, the amount of diffusion into the matrix increases, resulting in a decrease in the thermal conductivity of the matrix and a decrease in the effect of suppressing thermal expansion due to a change in the component composition of the iron-based alloy powder. On the other hand, if the overall particle size is too large, it becomes impossible to uniformly disperse the particles in the matrix, so that a portion where the effect of suppressing thermal expansion is locally weakened, and thermal expansion cannot be effectively suppressed.
[0017]
For these reasons, the iron-based alloy powder is preferably -100 mesh (passed through a 100 mesh sieve), and more preferably a powder having a particle size of 50 μm or less and a content of 60% or less is used. The iron-based alloy powder in which the powder having a particle size of 50 μm or less exceeds 60% has a large amount of fine powder and low thermal conductivity. As the copper powder for the matrix, use a powder of -100 mesh and a powder having a particle size of 50 μm or more and a content of 60% or less so that the particle size is smaller than that of the iron-based alloy powder. Is preferred. By adjusting the particle size of the iron-based alloy powder and the matrix powder in this manner, more effective heat conduction and thermal expansion suppression can be obtained.
[0018]
【Example】
<Example 1>
(Effects of coefficient of thermal expansion, addition amount, and sintering temperature of iron-based alloy powder)
A -100 mesh iron-based alloy powder having a coefficient of thermal expansion up to 100 ° C. shown in Table 1 and adjusted to a particle size configuration containing 40% of a powder of 50 μm or less was prepared.
[0019]
[Table 1]

[0020]
These iron-based alloy powders were added at a compounding ratio shown in Table 2 to copper powder adjusted to contain 40% of powder having a particle size of 50 μm or more with a mesh of -100, and after compacting at 1470 MPa, ammonia Sintering was performed at a temperature shown in Table 2 in a decomposed gas atmosphere to prepare Samples Nos. 01 to 31. Table 2 also shows the results of measuring the thermal conductivity and the coefficient of thermal expansion of these samples. In addition, graphs of the measurement results in Table 2 are shown in FIGS.
[0021]
[Table 2]

[0022]
Sample numbers 01 to 09 in Table 2 are obtained by changing the addition amount of the iron-based alloy powder (Fe-36Ni) to the copper powder. By comparing these samples, the effect of the addition amount of the iron-based alloy powder on the thermal conductivity and the coefficient of thermal expansion can be understood. FIG. 1 is a graph of this. From these results, Sample 02 in which the addition amount of the iron-based alloy powder is 5% by mass shows smaller values of the thermal conductivity and the coefficient of thermal expansion than Sample 01 in which the addition amount of the iron-based alloy powder is not added (100% of copper). It can be seen that it has been improved.
Further, it can be seen that the thermal conductivity and the thermal expansion coefficient tend to decrease as the addition amount of the iron-based alloy powder increases. However, in Sample 09 in which the addition amount of the iron-based alloy powder exceeds 60% by mass, the coefficient of thermal expansion is conversely increased. This is presumably because at the sintering temperature of 500 ° C., there were many iron-based alloy powders that were not bonded by sintering, and the expansion of copper could not be suppressed, and the coefficient of thermal expansion turned to an increasing tendency. That is, although the iron-based alloy powder in contact with the copper powder is bonded at the surface layer, the iron-based alloy powder is not bonded to each other. It is considered that the displacement occurred at the interface and the effect of suppressing thermal expansion was not obtained.
[0023]
Sample numbers 10 to 14, 15 to 19, and 20 to 24 changed the sintering temperature when the addition amount of the iron-based alloy powder (Fe-36Ni-5Co) was 30% by mass, 40% by mass, and 50% by mass, respectively. It is something. Comparison of these samples shows the effect of sintering temperature on thermal conductivity and coefficient of thermal expansion. FIG. 2 and FIG. 3 are graphs of this. From these results, it can be seen that as the sintering temperature increases, the thermal conductivity tends to decrease from 400 ° C., 500 ° C. to 600 ° C., and at 1000 ° C., the temperature significantly decreases. On the other hand, it can be seen that the coefficient of thermal expansion tends to decrease at 400 to 500 ° C. and then increase at a higher temperature, and shows a remarkable increase at 1000 ° C. This is considered to be due to the fact that at the sintering temperature of 1000 ° C., the copper powder and the iron-based alloy powder were diffused, and the characteristics were deteriorated. At a sintering temperature of 300 ° C., sintering of the matrix did not proceed, and the strength was poor. The above tendencies show the same tendencies irrespective of the amount of the iron-based alloy powder added. From these facts, it can be seen that the sintering temperature in the range of 400 to 600 ° C. is appropriate.
[0024]
Further, Sample Nos. 06, 17, 26, 29 and 31 were obtained by adding 40% by mass of iron-based alloy powders having different compositions and sintering them at 500 ° C. By comparing these samples, the effect of the type of the iron-based alloy powder on the thermal conductivity and the coefficient of thermal expansion can be understood. FIG. 4 is a graph of this. In any of these samples, when the iron-based alloy powder having a coefficient of thermal expansion up to 100 ° C. of 6 × 10 ⁻⁶ / K or less, there is almost no change in thermal conductivity depending on the type of the iron-based alloy powder, and the thermal expansion coefficient is small. It can be seen that the coefficient is suppressed to a small value.
[0025]
As described above, in the copper matrix, the iron-based alloy powder having a coefficient of thermal expansion of 6 × 10 ⁻⁶ / K or less up to 100 ° C. was dispersed in a mass ratio of 5 to 60%, and sintered at 400 to 600 ° C. It was confirmed that the sample did not significantly decrease in thermal conductivity and had a small coefficient of thermal expansion.
[0026]
<Example 2>
(Effect of granularity configuration)
Using -100 mesh copper powder and -100 mesh Fe-36Ni powder as the iron-based alloy powder, the powder having a ratio shown in sample numbers 06 and 32 to 39 in Table 3 was compacted at 1470 MPa, and then subjected to ammonia decomposition. Sintering was performed at 500 ° C. in a gas atmosphere. Table 3 also shows the results of measuring the thermal conductivity and the coefficient of thermal expansion of these samples.
[0027]
[Table 3]

[0028]
Sample Nos. 06 and 32 to 36 were prepared by mixing iron-based alloy powders having different powder amounts of 50 μm or less with copper powder having a powder amount of 50 μm or more of 60%. By comparing these, the influence of the content of the iron-based alloy powder of 50 μm or less on the thermal expansion coefficient and the thermal conductivity is understood. Table 3 shows that the coefficient of thermal expansion is constant, but the thermal conductivity increases as the amount of the iron-based alloy powder having a size of 50 μm or less decreases. In particular, a sample having a powder having a particle size of 50 μm or less having a powder content of 60% or less has a good thermal conductivity exceeding 100 W / m · K.
[0029]
Sample Nos. 06 and 37 to 39 are obtained by mixing iron-based alloy powder in which the amount of powder of 50 μm or less is 40% with the copper powder of which the amount of powder of 50 μm or more is different. By comparing these, it is understood that the difference in the content of the copper powder of 50 μm or more affects the thermal expansion coefficient and the thermal conductivity. It can be seen that as the content of the copper powder of 50 μm or more increases, the thermal conductivity decreases. A sample in which the amount of copper powder having a size of 50 μm or more has a content of 60% or less shows a good value of thermal conductivity exceeding 100 W / m · K.
[0030]
As described above, the matrix powder is -100 mesh powder, and the powder having a particle size of 50 μm or more is 60% or less, and the iron-based alloy powder is -100 mesh and the particle size is 50 μm or less. It was confirmed that the use of powder having a powder content of 60% or less was particularly effective.
[0031]
【The invention's effect】
According to the method for producing a copper-based low-thermal-expansion high-thermal-conductivity member according to the present invention, the iron-based alloy powder having a thermal expansion coefficient of up to 100 ° C. of 6 × 10 ⁻⁶ / K or less is slightly ^contained in the copper matrix. Thus, a copper-based low-thermal-expansion high-thermal-conductivity member having high thermal conductivity and a low coefficient of thermal expansion exhibiting a metal structure diffused with a matrix can be manufactured.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the addition amount of an iron-based alloy powder and the thermal conductivity and coefficient of thermal expansion.
FIG. 2 is a graph showing a relationship between a sintering temperature and a thermal conductivity at each addition amount of an iron-based alloy powder.
FIG. 3 is a graph showing a relationship between a sintering temperature and a coefficient of thermal expansion for each addition amount of an iron-based alloy powder.
FIG. 4 is a graph showing the relationship between the type of iron-based alloy powder and the thermal conductivity and coefficient of thermal expansion.

Claims

An iron-based alloy powder having a thermal expansion coefficient up to 100 ° C. of 6 × 10 ⁻⁶ / K or less is added to a copper powder at a mass ratio of 5 to 60%. A method for producing a copper-based low-thermal-expansion high-thermal-conductivity member, comprising sintering at 400 to 600 ° C. after compression-molding as described above.

The copper powder is -100 mesh powder, and the content of powder having a particle size of 50 μm or more is 60% or less, and the iron-based alloy powder is -100 mesh and the particle size is 50 μm or less. The method for producing a copper-based low-thermal-expansion high-thermal-conduction member according to claim 1, wherein the content of the powder is 60% or less.