JP2004323953A - Copper-based low thermal expansion high thermal conduction member, and its production method - Google Patents
Copper-based low thermal expansion high thermal conduction member, and its production method Download PDFInfo
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- JP2004323953A JP2004323953A JP2003123423A JP2003123423A JP2004323953A JP 2004323953 A JP2004323953 A JP 2004323953A JP 2003123423 A JP2003123423 A JP 2003123423A JP 2003123423 A JP2003123423 A JP 2003123423A JP 2004323953 A JP2004323953 A JP 2004323953A
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims abstract description 92
- 229910052802 copper Inorganic materials 0.000 title claims abstract description 54
- 239000010949 copper Substances 0.000 title claims abstract description 54
- 238000004519 manufacturing process Methods 0.000 title claims description 16
- 239000000843 powder Substances 0.000 claims abstract description 177
- 239000000956 alloy Substances 0.000 claims abstract description 84
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 83
- 229910000881 Cu alloy Inorganic materials 0.000 claims abstract description 73
- 238000004881 precipitation hardening Methods 0.000 claims abstract description 69
- 239000011159 matrix material Substances 0.000 claims abstract description 64
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 139
- 229910052742 iron Inorganic materials 0.000 claims description 69
- 239000002245 particle Substances 0.000 claims description 29
- 239000011812 mixed powder Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 abstract description 14
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 abstract description 11
- 239000000463 material Substances 0.000 abstract description 10
- 229910052750 molybdenum Inorganic materials 0.000 abstract description 9
- 239000011733 molybdenum Substances 0.000 abstract description 9
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 abstract description 8
- 229910052759 nickel Inorganic materials 0.000 abstract description 7
- 229910052721 tungsten Inorganic materials 0.000 abstract description 5
- 239000010937 tungsten Substances 0.000 abstract description 5
- 238000007747 plating Methods 0.000 abstract description 2
- 238000005245 sintering Methods 0.000 description 28
- 239000012071 phase Substances 0.000 description 21
- 230000007423 decrease Effects 0.000 description 19
- 230000000694 effects Effects 0.000 description 17
- 238000009792 diffusion process Methods 0.000 description 8
- 230000032683 aging Effects 0.000 description 7
- 238000002156 mixing Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 239000007791 liquid phase Substances 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- 229910001374 Invar Inorganic materials 0.000 description 3
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000000748 compression moulding Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000000280 densification Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 229910017813 Cu—Cr Inorganic materials 0.000 description 1
- 229910017824 Cu—Fe—P Inorganic materials 0.000 description 1
- 229910017985 Cu—Zr Inorganic materials 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- WUUZKBJEUBFVMV-UHFFFAOYSA-N copper molybdenum Chemical compound [Cu].[Mo] WUUZKBJEUBFVMV-UHFFFAOYSA-N 0.000 description 1
- SBYXRAKIOMOBFF-UHFFFAOYSA-N copper tungsten Chemical compound [Cu].[W] SBYXRAKIOMOBFF-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000002431 foraging effect Effects 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 229910000833 kovar Inorganic materials 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
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- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Abstract
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や、ＳｉチップをＣｕ、Ａｌ等の放熱板に積載するにあたり、両者の間に挿入され、Ｓｉチップの発熱を外部の放熱板に伝達するとともに、その製造において、Ｃｕ、Ａｌ等の放熱板に圧入されても変形せず、Ｓｉチップに応力を伝達しないことが要求される電子部品用銅基低熱膨張高熱伝導部材およびそ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】
【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
【０００４】
【発明が解決しようとする課題】
しかし、このような材料は、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、前者の特許文献１に記載の場合には、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、後者の特許文献２に記載の場合は、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。さらに、加工性の問題については特許文献１の場合と同様である。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。
【０００５】
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ことにある。
【０００６】
【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は、析出硬化型銅合金のマトリックス中に、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％分散することを特徴とする。
【０００７】
また、もう一つの本発明の銅基低熱膨張高熱伝導部材は、前記析出硬化型銅合金のマトリックスを、析出硬化型銅合金相と純銅相からなるマトリックスに置き換えるとともに、置き換えたマトリックス中の純銅相の割合が、質量比で、７５％以下としたことを特徴とする。このとき、純銅相がネットワーク状に分布すると好適である。
【０００８】
本発明の銅基低熱膨張高熱伝導部材の製造方法は、析出硬化型銅合金粉末、好ましくは析出硬化型銅合金の急冷凝固粉末からなるマトリックス粉末に、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、相対密度で９３％以上に圧縮成形した成形体を、４００〜６００℃で焼結することを特徴とする。
【０００９】
また、もう一つの本発明の銅基低熱膨張高熱伝導部材の製造方法は、マトリックス粉末として、析出硬化型銅合金粉末に、質量比で、純銅粉末を、７５％以下の割合で配合したマトリックス粉末を用いることを特徴とする。
【００１０】
上記の製造方法において、析出硬化型銅合金粉末が、−１００メッシュの粉末で、かつ粒径５０μｍ以上の粉末の含有量が７０％以下の粉末であり、鉄基合金粉末が、−１００メッシュで、かつ、５０μｍ以上の粉末が４０％以上の粉末であることが好ましく、さらに、銅粉末を用いる場合には、銅粉末が−１００メッシュで、かつ、５０μｍ以上の粉末が４０％以下のものを用いることが好ましい。
【００１１】
【発明の実施の形態】
本発明の銅基低熱膨張高熱伝導部材は、マトリックスとして析出硬化型銅合金を用いる。析出硬化型銅合金は、過飽和の合金成分が基地組織中に均一かつ微細に析出分散した組織を示し、硬さと強度に優れた合金である。このような析出硬化型銅合金をマトリックスとして用いたことにより、マトリックスの硬さと強度が向上し、圧入時の変形がほとんどない銅基低熱膨張高熱伝導部材が得られる。
【００１２】
析出硬化型銅合金としては、従来リードフレーム等で用いられているものが適用可能であり、Ｃｕ−Ｚｒ系、Ｃｕ−Ｆｅ−Ｐ系、Ｃｕ−Ｎｉ−Ｆｅ−Ｐ系、Ｃｕ−Ｃｒ系、Ｃｕ−Ｃｒ−Ｓｎ系等の合金が挙げられる。
【００１３】
析出硬化型銅合金の一般的な製法は、鋳造後、溶体化処理により合金成分を過飽和に基地中に固溶した後、時効処理により、基地中に過飽和に固溶した合金成分を析出させるものである。本発明の製造方法においては、析出硬化型銅合金粉末はアトマイズ時に既に溶体化が行われているに等しい状態であるので、この処理を省略できる。
【００１４】
また、溶体化の後、時効処理前に、歪みを与える処理を施すと、歪みが時効析出の駆動源となるため好ましいが、本発明の製造方法においては、圧粉成形時に粉末に歪みが蓄積するためこれを有効に活用できるという利点がある。このとき急冷凝固粉末を用いると、過飽和に固溶された成分が予め粉末に歪みを与えているので、より一層の歪みが蓄積され効果的である。
【００１５】
さらに、本発明において、後述する理由により焼結は４００〜６００℃で行うが、この温度は時効処理にきわめて有効な温度範囲であるため、焼結時にマトリックス中に析出物が時効析出することとなり、焼結による粉末の拡散結合と時効処理が同時に行えるため、別途、時効処理を行う必要がない。
【００１６】
したがって、本発明の製造方法における、析出硬化型銅合金の急冷凝固粉末の適用は、特に工程を増やすことなく、効果的に析出物の時効析出が行え、マトリックスの強化が容易にできる点から、極めて効果的である。
【００１７】
本願発明において用いる、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。
【００１８】
上記の１００℃までの熱膨張係数が６×１０−６／Ｋ以下の鉄基合金粉末は、上記の析出硬化型銅合金マトリックス中に分散するとともに、表面が僅かにマトリックスと反応しており、マトリックスと鉄基合金粉末の結合が強固であるため、マトリックスの熱膨張を鉄基合金粉末が強固に抑えて部材全体の熱膨張が抑制される。
【００１９】
このような析出硬化型銅合金マトリックスと鉄基合金粉末の拡散状態を得るために、本発明の製造方法においては、析出硬化型銅合金粉末と、鉄基合金粉末とを混合した混合粉末を、圧縮成形した後、４００〜６００℃の温度範囲で焼結を行う。
すなわち、焼結温度が４００℃より低いと析出硬化型銅合金マトリックス自体が十分に拡散形成されず、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析出硬化型銅合金マトリックスと必要以上に反応するために、熱膨張の抑制機能が低下するとともに、マトリックスの熱伝導性をも阻害することとなる。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、ニッケルのマトリックスへの拡散が著しく生じ、これらの不具合の度合いが大きい。
【００２０】
また、上記の温度範囲では銅の液相が発生しないため、寸法精度も優れたものとなる。
【００２１】
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こととなる。鉄基合金粉末が、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の量が少なくなるため熱伝導性の低下が著しくなるため５〜６０％の範囲が好適である。
【００２２】
上記のように、本発明の製造方法においては、鉄基合金粉末のマトリックスへの拡散を抑制するため、４００〜６００℃の温度で焼結するが、この温度では銅の液相が発生せず、焼結による緻密化の効果は小さいため、マトリックスの熱伝導率を高くするためには、予め混合粉末を相対密度で９３％以上に圧縮成形しておく必要がある。
【００２３】
上記のようなマトリックスを構成する析出硬化型銅合金粉末は、微粉末を用いることによって、ネック形成部を増加させ焼結による拡散を進行させることができる。さらに、析出硬化型銅合金粉末の粒度構成を鉄基合金粉末の粒度構成より細かくすることにより、マトリックスの連続性が高まり、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、鉄基合金粉末まで微粉にすると、粉末の流動性の低下や型かじり等の問題が発生するだけでなく、上述のような僅かの拡散相であっても、ネック形成部が増加することによりマトリックスとの拡散量が増加し、マトリックスの熱伝導性の低下や、鉄基合金粉末の組成が変化することによる鉄基合金粉末の熱膨張率の増大の現象が生じるようになる。逆に、全体の粉末の粒径が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薄まる箇所が生じ、効果的に熱膨張を抑制できなくなる。
【００２４】
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以上の粉末が４０％以上である粉末を用いることが一層好ましい。粒度構成として、５０μｍ以上の粉末の含有量が４０％に満たない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、析出硬化型銅合金粉末としては、上記鉄基合金粉末よりも粒度が小さくなるよう、−１００メッシュの粉末で、かつ粒径５０μｍ以上の粉末の含有量が７０％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析出硬化型銅合金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。
【００２５】
以上の銅基低熱膨張高熱伝導部材は、析出硬化型銅合金のマトリックス中に、１００℃までの熱膨張係数が６×１０−６／Ｋ以下の鉄基合金粉末が分散し、強度の高いもので、圧入時に変形せず、好適なものである。しかし、より一層の熱伝導性の向上を望む場合には、マトリックスを析出硬化型銅合金相と純銅相から構成するとともに、前記マトリックス中の純銅相の割合が、質量比で、７５％以下の割合で分散するマトリックスとすることで、強度の低下を招くことなく熱伝導性を向上させることができる。このとき、純銅相をマトリックス中にネットワーク状に分散させると好適である。
【００２６】
マトリックス中の純銅相の割合が、増加するにつれ熱伝導率は向上するが、５０％を越えると、添加の割には熱伝導率向上の効果は低くなる。
一方、マトリックス中の純銅相の割合が５０％程度まではほぼ一定の硬さを示すが、５０％を越えると硬さの低下傾向が生じ、７５％を越えると急激に硬さが低下することとなる。したがって、マトリックス中の純銅相の割合は、質量比で、７５％以下にする必要がある。好ましくは、熱伝導率向上の効果が顕著な２５〜７５％である。
【００２７】
このような銅基低熱膨張高熱伝導部材は、マトリックス粉末として、析出硬化型銅合金粉末に、質量比で、純銅粉末を７５％以下（好ましくは２５〜７５％）の割合で配合したマトリックス粉末を用いることにより容易に得ることができる。
【００２８】
また、析出硬化型銅合金粉末と鉄基合金粉末の粒度構成は、前述のとおりであるが、同時に用いる純銅粉末として、析出硬化型銅合金粉末よりも微細な純銅粉末を用いることが好ましい。これにより、析出硬化型銅合金粉末および／または鉄基合金粉末の間において、純銅粉末の存在確率が高まり、これを成形−焼結することにより、ネットワーク状に分散する純銅相が得られ、熱伝導性の点で好ましい。
【００２９】
このことから、純銅粉末として、−１００メッシュで、かつ、粒径５０μｍ以上の粉末を４０％以下含有している粉末を用いる。５０μｍ以上の粉末が４０％を越えると、粒度構成が粗粉側に移行し、ネットワーク状の純銅相が得難くなる。
【００３０】
【実施例】
＜実施例１＞
表１に示す１００℃までの熱膨張係数を有し、粒度構成として、５０μｍ以上の粉末を４０％含有するように調整した−１００メッシュの各種鉄基合金粉末を用意した。
【００３１】
【表１】
これらの鉄基合金粉末を、−１００メッシュで粒径５０μｍ以上の粉末を７０％含有するように調整した表２および表４に示す各種析出硬化型銅合金粉末、および−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純銅粉末とともに、表２および表４に示す配合割合で混合した。その後１４７０ＭＰａで圧粉成形した後、アンモニア分解ガス雰囲気中、表３および表５に示す温度で焼結を行い試料番号０１〜３７の試料を作製した。これらの試料につき、熱伝導率、熱膨張係数および硬さについて測定した結果を表３および表５に併せて示す。
【００３３】
【表２】
【表３】
【表４】
【表５】
試料番号０１〜０５、１０および１７〜１９の試料は析出硬化型銅合金粉末（Ｃｕ−０．３Ｎｉ−０．３Ｆｅ−０．１５Ｐ）に鉄基合金粉末（Ｆｅ−３６Ｎｉ）の添加量を変えたものである。これら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、熱膨張係数および硬さに及ぼす影響がわかる。これらの内、鉄基合金粉末の添加量と熱伝導率、熱膨張係数の関係をグラフ化したものを図１に示す。
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、これらの特性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つれて熱伝導率および熱伝導率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１９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、析出硬化型銅合金マトリックス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る。
すなわち、析出硬化型銅合金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ものと考える。
【００３８】
試料番号０５〜０９の試料、および試料番号１０〜１６の試料はそれぞれ鉄基合金粉末（Ｆｅ−３６Ｎｉ）の添加量を一定として、析出硬化型銅合金粉末（Ｃｕ−０．３Ｎｉ−０．３Ｆｅ−０．１５Ｐ）と純銅粉末の配合比率をかえたものである。これらを比較することで、マトリックス粉末における純銅粉末の割合が熱伝導率、熱膨張係数および硬さに及ぼす影響がわかる。これらの内、純銅粉末の割合と熱伝導率の関係をグラフ化したものが図２、純銅粉末の割合と硬さの関係をグラフ化したものが図３である。
これらの結果より、析出硬化型銅合金粉末に純銅粉末を添加しても、表３から熱膨張係数は一定であるが、図２から熱伝導率は、純銅粉末２５質量％の添加により向上することがわかる。ただし、５０質量％を超えて添加しても、添加の割に熱伝導率向上の効果は少なくなることがわかる。一方、図３から硬さは純銅粉末の添加量が５０質量％までは一定の高い値を示すが、５０質量％を超えると低下する傾向を示し、７５質量％を超えると著しく低下する。したがって、純銅粉末の添加は熱伝導率を向上させるが、添加量は、硬さの点から７５質量％以下が適切であることがわかる。
【００３９】
試料番号２０〜２４は析出硬化型銅合金粉末（Ｃｕ−０．３Ｎｉ−０．３Ｆｅ−０．１５Ｐ）６０質量％と鉄基合金粉末（Ｆｅ−３６Ｎｉ）４０質量％からなる混合粉末の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で、焼結温度が熱伝導率、熱膨張係数および硬さに及ぼす影響がわかる。焼結温度と熱伝導率および熱膨張係数の関係をグラフ化したものが図４、焼結温度と硬さの関係をグラフ化したものが図５である。
これらより、焼結温度が上昇すると熱伝導率は４００℃までは向上し、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℃で低下した後、値が大きくなる傾向を示し、１０００℃では著しい増加を示すことがわかる。また、硬さは焼結温度が高くなるにつれ向上するが、５００℃をピークとして低下する傾向を示し、１０００℃では著しく硬さが低下する。これらの現象は、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。
以上の傾向は添加量に依らず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。
【００４０】
試料番号１０、２２、２５〜２７の試料、試料番号２８〜３２の試料、および試料番号３３〜３７の試料は、各々、同一の析出硬化型銅合金に対して１００℃までの熱膨張係数が６×１０−６／Ｋ以下の鉄基合金粉末の種類を替えた場合の比較である。また試料番号１６は析出硬化型銅合金でなく純銅粉末を用いたものとして比較の対象とした。これにより鉄基合金粉末の種類を替えた場合、熱伝導率、熱膨張係数および硬さの変化がわかる。これを棒グラフにしたものが図６〜８である。なお棒の上の数字は試料番号を示す。
これらより、熱伝導率は基地を替えた場合に、基地の熱伝導率により変化するが、添加する鉄基合金粉の影響は少ないことがわかる。また、熱膨張係数は鉄基合金粉末を添加しない場合より低い値を示し、いずれの鉄基合金粉末を用いてもほぼ同等の値であることがわかる。さらに、硬さはいずれの析出硬化型銅合金、鉄基合金粉末を用いた場合でも純銅のものより向上していることがわかる。
【００４１】
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％分散する試料が熱伝導率が大きく、かつ熱膨張係数が小さいこと、および焼結温度が４００〜６００℃の試料が熱伝導率が大きく、熱膨張係数が小さく、かつ硬さが高いことが確認された。
また、析出硬化型銅合金の種類を替えても、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れば、析出硬化型銅合金の特性により熱伝導率の差異はあるものの熱膨張係数および硬さについては同等の特性が得られることが確認された。なお、上記の析出硬化型銅合金の特性により熱伝導率の差異は、純銅粉末を７５質量％以下添加することで向上させることができることもわかり、本願発明の効果が確認された。
【００４２】
＜実施例２＞
表６に示す純銅粉末と、析出硬化型銅合金粉末としてＣｕ−０．３Ｎｉ−０．３Ｆｅ−０．１５Ｐ合金粉と、１００℃までの熱膨張係数が６×１０−６／Ｋ以下の鉄基合金粉末としてＦｅ−３６Ｎｉ粉末を用い、析出硬化型銅合金粉末：３０質量％、純銅粉末：３０質量％および鉄基合金粉末：４０質量％の割合で配合し混合粉末を得た。これを１４７０ＭＰａで圧粉成形した後、アンモニア分解ガス雰囲気中、５００℃で焼結を行い試料番号３８〜５０の試料を作製した。これらの試料につき、熱伝導率と、硬さについて測定した結果を、実施例１の試料番号１３の試料とともに表６に併せて示す。
【００４３】
【表６】
試料番号１３、３８〜４２を比較することによって、析出硬化型銅合金粉末中の５０μｍ以上の粉末の割合の熱伝導率および硬さへの影響がわかる。これらをグラフ化したものを図９に示す。析出硬化型銅合金粉末中の５０μｍ以上の粉末の割合が増加すると、若干の熱伝導率の向上が認められるが、７５％を超えると熱伝導率の低下が認められる。
【００４５】
これは、析出硬化型銅合金粉末の粒度が小さい側では、析出硬化型銅合金粉末の表面積が大きくなり、析出硬化型銅合金粉末どうし、および析出硬化型銅合金粉末と純銅粉末または鉄基合金粉末との接触点が多くなり、拡散の進行を促進してより緻密化されてマトリックスの熱伝導性が向上するためと考える。また、析出硬化型銅合金粉末の粒度が、純銅粉末の粒度よりも微粉側では、ネットワーク状純銅相の形成を阻害し、一部の純銅相が遊離して分散したため熱伝導率の若干の低下につながったともの考える。
一方、析出硬化型銅合金粉末中の５０μｍ以上の粉末の割合が７５％を越えると、局部的に析出硬化型銅合金粉末の割合が高まる結果、均一な熱伝導が阻害され始めるからと考えられる。よって、析出硬化型銅合金粉末中の５０μｍ以上の粉末の割合は７０％以下が好ましいことが確認された。
【００４６】
試料番号１３、４３〜４６を比較することによって、純銅粉末中の５０μｍ以上の粉末の割合の熱伝導率および硬さへの影響がわかる。これをグラフ化したものが図１０である。これらより、純銅粉末中の５０μｍ以上の粉末の割合が４０％以下ではほぼ均一な熱伝導率を示すが、４０％を超えると若干の低下傾向が認められる。
【００４７】
これは純銅粉末の粒度の小さい側では、純銅粉末の表面積が大きくなり、純銅粉末どうし、および純銅粉末と析出硬化型銅合金粉末または鉄基合金粉末との接触点が多くなり、拡散の進行を促進してより緻密化されてマトリックスの熱伝導性が向上するため、および微細な純銅粉末が析出硬化型銅合金粉末および／または鉄基合金粉末の間に存在する確率が増し、ネットワーク状純銅相を形成するためと考えられる。
一方、純銅粉末の５０μｍ以上の粉末の割合が４０％を越えると、局部的にネットワーク状純銅相の形成が阻害され始め、熱伝導率の低下が始まるものと考えられる。よって、純銅粉末の５０μｍ以上の粉末の割合は、４０％以下が好ましいことが確認された。
【００４８】
試料番号１３、４７〜５０を比較することによって、鉄基合金粉末の粒径５０μｍ以上の粉末の割合の熱伝導率および硬さへの影響がわかる。これをグラフ化したものが図１１である。
これらより、鉄基合金粉末の５０μｍ以上の粉末の割合が４０％以上ではほぼ一定の熱伝導率を示すが、４０％未満では若干の熱伝導率の低下が認められる。これは、鉄基合金粉末が微粉側に片寄り、マトリックスと拡散し易くなり、熱伝導率が低下したものと考える。よって、鉄基合金粉末の５０μｍ以上の粉末の割合は、４０％以上が好ましいことが確認された。
【００４９】
【発明の効果】
本発明による銅基低熱膨張高熱伝導部材は、析出硬化型銅合金マトリックスまたは析出硬化型銅合金相と純銅相からなるマトリックス中に、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％分散するものである。これにより、マトリックスに僅かに拡散した鉄基合金粉末がマトリックスの熱膨張を強固に抑制し、高い熱伝導性と低い熱膨張率を兼ね備え、かつ、硬さと強度に優れたもので、安価であること、加工性が高いことなどの優れた特性を示す。
また、本発明による銅基低熱膨張高熱伝導部材は、溶体化処理および時効処理を別途行う必要が無く、簡便な工程で、容易に製造することができるものである。
【図面の簡単な説明】
【図１】析出硬化型銅合金粉末に対する鉄基合金粉末の添加量と熱伝導率および熱膨張係数の関係を示すグラフである。
【図２】鉄基合金粉末の添加量を一定にして、マトリックス粉末における純銅粉末の割合と熱伝導率の関係を示すグラフである。
【図３】鉄基合金粉末の添加量を一定にして、マトリックス粉末における純銅粉末の割合と硬さ関係を示すグラフである。
【図４】析出硬化型銅合金粉末と鉄基合金粉末の配合量を一定にした場合の、焼結温度と熱伝導率および熱膨張係数の関係を示すグラフである。
【図５】析出硬化型銅合金粉末と鉄基合金粉末の配合量を一定にした場合の、焼結温度と硬さの関係を示すグラフである
【図６】各種の析出硬化型銅合金に対する鉄基合金粉末の種類を替えた場合の熱伝導率の比較を示すグラフである。
【図７】各種の析出硬化型銅合金に対する鉄基合金粉末の種類を替えた場合の熱膨張係数の比較を示すグラフである。
【図８】各種の析出硬化型銅合金に対する鉄基合金粉末の種類を替えた場合の硬さの比較を示すグラフである。
【図９】析出硬化型銅合金粉末中の５０μｍ以上の粉末の割合の、熱伝導率および硬さに対する影響を示すグラフである。
【図１０】純銅粉末中の５０μｍ以上の粉末の割合の、熱伝導率および硬さへの影響を示すグラフである。
【図１１】鉄基合金粉末中の５０μｍ以上の粉末の割合の、熱伝導率および硬さへの影響を示すグラフである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention has a thermal expansion coefficient equivalent to that of a Si chip, a ceramic substrate, or the like, and a heat sink that requires high heat radiation, and a Si chip mounted on a heat radiating plate of Cu, Al, or the like. Copper for electronic components that is required to transmit the heat of the Si chip to an external heat radiating plate and not to be deformed even when pressed into a heat radiating plate of Cu, Al, etc. and to transmit no stress to the Si chip in its manufacture. The present invention relates to a base member having a low thermal expansion and a high thermal conductivity and a method of manufacturing the same.
[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]
[Patent Document 1]
JP-A-62-284032
[Patent Document 2]
JP-A-59-21032
[0004]
[Problems to be solved by the invention]
However, since such materials are expensive as molybdenum powder or tungsten powder as a raw material, a major problem is that the material cost itself increases. Further, in the case of the former patent document 1, since liquid phase sintering is performed, it is easily deformed and has large dimensional variations. Therefore, processing is required after sintering, but molybdenum is hard and has low workability. The material in which such a phase is dispersed also has a problem that workability is low. Further, in the case of the latter Patent Document 2, it is difficult to infiltrate copper into all gaps of the skeleton, so that thermal conductivity is inferior and quality tends to vary, and after high-temperature sintering in advance, The process cost increases because copper is infiltrated. Further, the problem of workability is the same as in the case of Patent Document 1. 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.
[0005]
An object of the present invention is to provide a high heat conductive member that has good dimensional accuracy, is excellent in workability, and can be plated with nickel, without using expensive materials such as molybdenum and tungsten.
[0006]
[Means for Solving the Problems]
The copper-based low thermal expansion high thermal conductive member of the present invention has a coefficient of thermal expansion up to 100 ° C. of 6 × 10 -6 / K or less is dispersed in a mass ratio of 5 to 60%.
[0007]
Further, another copper-based low thermal expansion high thermal conductive member of the present invention, the matrix of the precipitation hardening type copper alloy is replaced with a matrix consisting of a precipitation hardening type copper alloy phase and a pure copper phase, and the pure copper phase in the replaced matrix. Is 75% or less by mass. At this time, it is preferable that the pure copper phase is distributed like a network.
[0008]
The method for producing a copper-based low-thermal-expansion high-thermal-conductivity member according to the present invention is characterized in that a matrix powder composed of a precipitation-hardened copper alloy powder, preferably a rapidly solidified powder of a precipitation-hardened copper alloy, has a coefficient of thermal expansion up to 100 ° C. of 6 × 10 -6 / K or less of iron-based alloy powder is added at a mass ratio of 5 to 60%, and the mixed powder is subjected to compression molding at a relative density of 93% or more. It is characterized by the following.
[0009]
Further, another method for producing a copper-based low thermal expansion high thermal conductive member according to the present invention is a method of producing a matrix powder in which pure copper powder is blended as a matrix powder with a precipitation hardening type copper alloy powder in a mass ratio of 75% or less. Is used.
[0010]
In the above production method, the precipitation hardening type copper alloy powder is -100 mesh powder, and the content of powder having a particle size of 50 μm or more is 70% or less, and the iron-based alloy powder is -100 mesh. And, it is preferable that the powder of 50 μm or more is a powder of 40% or more. Further, when copper powder is used, the copper powder is -100 mesh and the powder of 50 μm or more is 40% or less. Preferably, it is used.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The copper-based low thermal expansion high thermal conductive member of the present invention uses a precipitation hardening type copper alloy as a matrix. The precipitation hardening type copper alloy has a structure in which a supersaturated alloy component is uniformly and finely precipitated and dispersed in a base structure, and is excellent in hardness and strength. By using such a precipitation hardening type copper alloy as a matrix, the hardness and the strength of the matrix are improved, and a copper-based low thermal expansion and high thermal conductive member with little deformation at the time of press-fitting can be obtained.
[0012]
As the precipitation hardening type copper alloy, those conventionally used in lead frames and the like are applicable, and Cu-Zr-based, Cu-Fe-P-based, Cu-Ni-Fe-P-based, Cu-Cr-based, An alloy such as a Cu-Cr-Sn-based alloy may be used.
[0013]
The general manufacturing method of precipitation hardening type copper alloy is to cast the alloy component into a supersaturated alloy solution by solution treatment and then to precipitate the supersaturated alloy component in the matrix by aging treatment. It is. In the production method of the present invention, since the precipitation hardening type copper alloy powder is in a state equivalent to that in which solution treatment has already been performed at the time of atomization, this treatment can be omitted.
[0014]
Further, after the solution treatment, it is preferable to perform a treatment for giving a strain before the aging treatment, since the strain serves as a driving source of the aging precipitation, but in the production method of the present invention, the strain is accumulated in the powder at the time of compacting. This has the advantage that it can be used effectively. At this time, when the rapidly solidified powder is used, since the component dissolved in supersaturation gives distortion to the powder in advance, more distortion is accumulated and it is effective.
[0015]
Furthermore, in the present invention, sintering is performed at 400 to 600 ° C. for the reason described below, but since this temperature is in a temperature range that is extremely effective for aging treatment, precipitates are age-precipitated in the matrix during sintering. In addition, since the diffusion bonding of powder by sintering and the aging treatment can be performed at the same time, it is not necessary to separately perform the aging treatment.
[0016]
Therefore, in the production method of the present invention, the application of the rapidly solidified powder of the precipitation hardening type copper alloy, without particularly increasing the number of steps, can effectively perform aging precipitation of the precipitate, and can easily strengthen the matrix. Extremely effective.
[0017]
The thermal expansion coefficient up to 100 ° C. used in the present invention is 6 × 10 -6 / K or less as an iron-based alloy, Invar (Fe-36Ni), Super Invar (Fe-31Ni-5Co), Stainless Invar (Fe-52.3Co-10.4Cr), Kovar (Fe-29Ni-17Co), Alloys such as 42 alloy (Fe-42Ni) and Fe-17B alloy. These alloys are inexpensive as compared with the above-mentioned molybdenum and tungsten, and have excellent workability.
[0018]
The thermal expansion coefficient up to 100 ° C. is 6 × 10 -6 / K or less is dispersed in the above precipitation hardening type copper alloy matrix, and the surface slightly reacts with the matrix. Since the bond between the matrix and the iron based alloy powder is strong, the matrix Is strongly suppressed by the iron-based alloy powder, thereby suppressing the thermal expansion of the entire member.
[0019]
In order to obtain the diffusion state of the precipitation hardening type copper alloy matrix and the iron-based alloy powder, in the production method of the present invention, a precipitation hardening type copper alloy powder and a mixed powder obtained by mixing the iron-based alloy powder, After compression molding, sintering is performed in a temperature range of 400 to 600 ° C.
That is, if the sintering temperature is lower than 400 ° C., the precipitation hardening type copper alloy matrix itself is not sufficiently diffused and formed, resulting in poor thermal conductivity and strength. Since it reacts more than necessary with the copper alloy matrix, the function of suppressing thermal expansion is reduced, and the thermal conductivity of the matrix is also impaired. In particular, when an iron-based alloy containing nickel is used as the iron-based alloy powder, since copper and nickel are completely dissolved, nickel significantly diffuses into the matrix, and the degree of these problems is large.
[0020]
Further, since the liquid phase of copper does not occur in the above temperature range, the dimensional accuracy is excellent.
[0021]
The above-mentioned iron-based alloy powder has a greater effect of suppressing thermal expansion as the amount of dispersion in the matrix increases, but the thermal conductivity decreases as the amount of 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 amount of the matrix is reduced, and the thermal conductivity is significantly reduced. Is suitable.
[0022]
As described above, in the production method of the present invention, in order to suppress the diffusion of the iron-based alloy powder into the matrix, sintering is performed at a temperature of 400 to 600 ° C., but at this temperature, a liquid phase of copper is not generated. Since the effect of densification by sintering is small, in order to increase the thermal conductivity of the matrix, it is necessary to previously compress the mixed powder to a relative density of 93% or more.
[0023]
The precipitation hardening type copper alloy powder constituting the matrix as described above can increase the neck forming portion and promote diffusion by sintering by using fine powder. Further, by making the particle size composition of the precipitation hardening type copper alloy powder finer than the particle size composition of the iron-based alloy powder, the continuity of the matrix can be increased and the thermal conductivity can be improved.
On the premise of this, if the powder is reduced to the iron-based alloy powder, not only problems such as a decrease in the fluidity of the powder and mold galling occur, but also a slight diffusion phase as described above, The amount of diffusion with the matrix increases due to the increase in the neck forming part, and the phenomenon of a decrease in the thermal conductivity of the matrix and an increase in the coefficient of thermal expansion of the iron-based alloy powder due to a change in the composition of the iron-based alloy powder occur. Will occur. On the other hand, if the particle size of the whole powder is too large, it will not be possible to uniformly disperse the powder in the matrix, and there will be places where the effect of suppressing the thermal expansion is locally reduced, and the thermal expansion cannot be suppressed effectively.
[0024]
For these reasons, the iron-based alloy powder is preferably -100 mesh (passed through a 100 mesh sieve), and more preferably 40% or more of powder having a particle size of 50 μm or more. The iron-based alloy powder in which the content of powder having a particle size of 50 μm or more is less than 40% has a large amount of fine powder and low thermal conductivity.
As the precipitation hardening type copper alloy powder, use a powder of -100 mesh and a powder having a particle size of 50 μm or more and a content of 70% 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 precipitation hardening type copper alloy powder in this manner, more effective heat conduction and thermal expansion suppression can be obtained.
[0025]
The above copper-based low thermal expansion high thermal conductive member has a coefficient of thermal expansion up to 100 ° C. of 6 × 10 in the matrix of the precipitation hardening type copper alloy. -6 / K or less are dispersed and have high strength, do not deform at the time of press-fitting, and are suitable. However, when further improvement in thermal conductivity is desired, the matrix is composed of a precipitation hardening type copper alloy phase and a pure copper phase, and the ratio of the pure copper phase in the matrix is 75% or less by mass. By using a matrix that is dispersed in a proportion, the thermal conductivity can be improved without lowering the strength. At this time, it is preferable that the pure copper phase is dispersed in a matrix form in the matrix.
[0026]
As the proportion of the pure copper phase in the matrix increases, the thermal conductivity improves. However, if it exceeds 50%, the effect of improving the thermal conductivity decreases for the addition.
On the other hand, although the hardness of the pure copper phase in the matrix is almost constant up to about 50%, the hardness tends to decrease when it exceeds 50%, and the hardness decreases rapidly when it exceeds 75%. It becomes. Therefore, the proportion of the pure copper phase in the matrix needs to be 75% or less by mass. Preferably, the effect of improving the thermal conductivity is 25 to 75%.
[0027]
Such a copper-based low-thermal-expansion high-thermal-conductivity member comprises, as a matrix powder, a matrix powder obtained by blending pure copper powder in a mass ratio of 75% or less (preferably 25 to 75%) with a precipitation hardening type copper alloy powder. It can be easily obtained by using.
[0028]
Although the particle size configurations of the precipitation hardening type copper alloy powder and the iron-based alloy powder are as described above, it is preferable to use pure copper powder finer than the precipitation hardening type copper alloy powder as the pure copper powder used at the same time. Thereby, the existence probability of the pure copper powder is increased between the precipitation hardening type copper alloy powder and / or the iron-based alloy powder, and a pure copper phase dispersed in a network is obtained by forming and sintering the pure copper powder. It is preferable in terms of conductivity.
[0029]
For this reason, a powder containing −100 mesh and containing 40% or less of powder having a particle size of 50 μm or more is used as pure copper powder. If the content of the powder having a particle size of 50 μm or more exceeds 40%, the particle size composition shifts to the coarse powder side, and it becomes difficult to obtain a network-like pure copper phase.
[0030]
【Example】
<Example 1>
Various iron-based alloy powders having a thermal expansion coefficient up to 100 ° C. shown in Table 1 and having a particle size of -100 mesh adjusted to contain 40% of powder having a particle size of 50 μm or more were prepared.
[0031]
[Table 1]
These iron-based alloy powders were prepared from various precipitation hardening type copper alloy powders shown in Tables 2 and 4 adjusted to contain 70% of a powder having a particle size of 50 μm or more at −100 mesh, and a particle size of 50 μm at −100 mesh. The powder was mixed with pure copper powder adjusted to contain 40% at the mixing ratios shown in Tables 2 and 4. Then, after compacting at 1470 MPa, sintering was performed in an ammonia decomposition gas atmosphere at the temperatures shown in Tables 3 and 5 to prepare samples Nos. 01 to 37. The results of measuring the thermal conductivity, the coefficient of thermal expansion, and the hardness of these samples are also shown in Tables 3 and 5.
[0033]
[Table 2]
[Table 3]
[Table 4]
[Table 5]
Samples Nos. 01-05, 10 and 17-19 were prepared by changing the addition amount of iron-based alloy powder (Fe-36Ni) to precipitation hardening type copper alloy powder (Cu-0.3Ni-0.3Fe-0.15P). It is a thing. By comparing these, the effect of the addition amount of the iron-based alloy powder on the thermal conductivity, the thermal expansion coefficient, and the hardness is understood. FIG. 1 shows a graph of the relationship between the amount of the iron-based alloy powder added, the thermal conductivity, and the coefficient of thermal expansion.
From these results, it was found that Sample 02, in which the addition amount of the iron-based alloy powder was 5% by mass, exhibited smaller values of the thermal conductivity and the coefficient of thermal expansion than
In other words, the iron-based alloy powder that is in contact with the precipitation hardening type copper alloy powder is bonded at the surface layer, but the iron-based alloy powder is not bonded to each other. It is considered that a shift occurred at the interface between the alloy powders and the effect of suppressing thermal expansion was not obtained.
[0038]
Sample Nos. 05 to 09 and Sample Nos. 10 to 16 were prepared by keeping the addition amount of the iron-based alloy powder (Fe-36Ni) constant, respectively, while precipitating hardening type copper alloy powder (Cu-0.3Ni-0.3Fe). -0.15P) and the mixing ratio of pure copper powder. By comparing these, the effect of the proportion of the pure copper powder in the matrix powder on the thermal conductivity, the coefficient of thermal expansion, and the hardness is understood. Among them, FIG. 2 is a graph showing the relationship between the ratio of the pure copper powder and the thermal conductivity, and FIG. 3 is a graph showing the relationship between the ratio of the pure copper powder and the hardness.
From these results, even when pure copper powder is added to the precipitation hardening type copper alloy powder, the thermal expansion coefficient is constant from Table 3, but the thermal conductivity is improved by adding 25% by mass of pure copper powder from FIG. You can see that. However, it can be seen that even if it is added in excess of 50% by mass, the effect of improving the thermal conductivity is reduced for the addition. On the other hand, from FIG. 3, the hardness shows a constant high value when the amount of pure copper powder added is up to 50% by mass, but tends to decrease when it exceeds 50% by mass, and decreases significantly when it exceeds 75% by mass. Therefore, it can be seen that the addition of pure copper powder improves the thermal conductivity, but the addition amount is preferably 75% by mass or less from the viewpoint of hardness.
[0039]
Sample Nos. 20-24 sinter a mixed powder composed of 60% by mass of precipitation hardening type copper alloy powder (Cu-0.3Ni-0.3Fe-0.15P) and 40% by mass of iron-based alloy powder (Fe-36Ni). It is a change in temperature. Comparing these samples shows the effect of sintering temperature on thermal conductivity, coefficient of thermal expansion, and hardness. FIG. 4 is a graph showing the relationship between the sintering temperature and the thermal conductivity and the coefficient of thermal expansion, and FIG. 5 is a graph showing the relationship between the sintering temperature and the hardness.
From these results, it can be seen that when the sintering temperature increases, the thermal conductivity increases up to 400 ° C., and tends to decrease from 500 ° C. to 600 ° C., and remarkably decreases at 1000 ° C. On the other hand, it can be seen that the coefficient of thermal expansion tends to increase after decreasing at 400 ° C. and to increase significantly at 1000 ° C. The hardness increases as the sintering temperature increases, but tends to decrease at a peak of 500 ° C., and at 1000 ° C., the hardness decreases significantly. It is considered that these phenomena are due to the fact that at the sintering temperature of 1000 ° C., the copper powder and the iron-based alloy powder are diffused and the properties are deteriorated. At a sintering temperature of 300 ° C., sintering of the matrix did not proceed, and the strength was poor.
The above tendency shows the same tendency irrespective of the addition amount, and it is understood from these that the sintering temperature in the range of 400 to 600 ° C. is appropriate.
[0040]
Sample Nos. 10, 22, 25 to 27, Sample Nos. 28 to 32, and Sample Nos. 33 to 37 each have a coefficient of thermal expansion up to 100 ° C. for the same precipitation hardening type copper alloy. 6 × 10 -6 This is a comparison when the type of iron-based alloy powder of / K or less is changed. Sample No. 16 was used as a comparison object because pure copper powder was used instead of the precipitation hardening type copper alloy. Thus, when the type of the iron-based alloy powder is changed, changes in the thermal conductivity, the coefficient of thermal expansion, and the hardness are found. This is shown in a bar graph in FIGS. The numbers above the bars indicate the sample numbers.
From these, it can be seen that the thermal conductivity changes with the thermal conductivity of the matrix when the matrix is changed, but the effect of the added iron-based alloy powder is small. Further, the coefficient of thermal expansion shows a lower value than the case where no iron-based alloy powder is added, and it can be seen that the values are almost the same regardless of which iron-based alloy powder is used. Further, it can be seen that the hardness is higher than that of pure copper when using any of the precipitation hardening type copper alloy and the iron-based alloy powder.
[0041]
As described above, the coefficient of thermal expansion up to 100 ° C. in the copper matrix is 6 × 10 -6 / K or less of the iron-based alloy powder dispersed in a mass ratio of 5 to 60% has a large thermal conductivity and a small coefficient of thermal expansion, and a sample having a sintering temperature of 400 to 600 ° C. It was confirmed that the modulus was large, the coefficient of thermal expansion was small, and the hardness was high.
Further, even if the type of the precipitation hardening type copper alloy is changed, the coefficient of thermal expansion up to 100 ° C. is 6 × 10 -6 It has been confirmed that, with an iron-based alloy powder of not more than / K, there are differences in thermal conductivity due to the properties of the precipitation hardening type copper alloy, but equivalent properties can be obtained in terms of thermal expansion coefficient and hardness. In addition, it was also found that the difference in thermal conductivity due to the characteristics of the precipitation hardening type copper alloy can be improved by adding pure copper powder at 75% by mass or less, and the effect of the present invention was confirmed.
[0042]
<Example 2>
Pure copper powder shown in Table 6, Cu-0.3Ni-0.3Fe-0.15P alloy powder as a precipitation hardening type copper alloy powder, and a coefficient of thermal expansion up to 100 ° C of 6 × 10 -6 Fe / 36Ni powder was used as the iron-based alloy powder having a concentration of / K or less, and the mixture powder was blended at a ratio of 30% by mass of precipitation hardening type copper alloy powder, 30% by mass of pure copper powder and 40% by mass of iron-based alloy powder. Obtained. After this was compacted at 1470 MPa, it was sintered at 500 ° C. in an ammonia decomposition gas atmosphere to prepare Sample Nos. 38 to 50. The results of measuring the thermal conductivity and hardness of these samples are shown in Table 6 together with the sample of Sample No. 13 of Example 1.
[0043]
[Table 6]
By comparing Sample Nos. 13 and 38 to 42, it can be seen that the influence of the proportion of the powder of 50 μm or more in the precipitation hardening type copper alloy powder on the thermal conductivity and hardness. FIG. 9 shows these in a graph. When the proportion of the powder having a size of 50 μm or more in the precipitation hardening type copper alloy powder increases, a slight improvement in the thermal conductivity is recognized, but when it exceeds 75%, a decrease in the thermal conductivity is recognized.
[0045]
This is because, on the side where the particle size of the precipitation hardening type copper alloy powder is small, the surface area of the precipitation hardening type copper alloy powder increases, and the precipitation hardening type copper alloy powder and the precipitation hardening type copper alloy powder and pure copper powder or iron-based alloy This is considered to be because the number of contact points with the powder increases, the progress of diffusion is promoted, and the powder is further densified to improve the thermal conductivity of the matrix. In addition, the grain size of the precipitation hardening type copper alloy powder, on the finer powder side than the grain size of the pure copper powder, hinders the formation of a network-like pure copper phase, and a part of the pure copper phase is released and dispersed, so that the thermal conductivity slightly decreases. Think that it led to.
On the other hand, when the proportion of the powder having a particle size of 50 μm or more in the precipitation hardening type copper alloy powder exceeds 75%, the ratio of the precipitation hardening type copper alloy powder locally increases, so that it is considered that uniform heat conduction starts to be hindered. . Therefore, it was confirmed that the ratio of the powder having a size of 50 μm or more in the precipitation hardening type copper alloy powder is preferably 70% or less.
[0046]
By comparing Sample Nos. 13 and 43 to 46, the influence on the thermal conductivity and hardness of the proportion of the powder having a size of 50 μm or more in the pure copper powder can be understood. FIG. 10 is a graph of this. From these, when the proportion of the powder having a size of 50 μm or more in the pure copper powder is 40% or less, the heat conductivity is almost uniform, but when the proportion exceeds 40%, a slight decrease tendency is recognized.
[0047]
This is because the surface area of the pure copper powder increases on the smaller particle size side of the pure copper powder, the number of contact points between the pure copper powder and the pure copper powder and the precipitation hardening type copper alloy powder or the iron-based alloy powder increases, and the diffusion progresses. Promotes more densification and improves the thermal conductivity of the matrix, and increases the probability that fine pure copper powder will be present between the precipitation hardening type copper alloy powder and / or the iron-based alloy powder; It is thought to form
On the other hand, when the proportion of the powder having a diameter of 50 μm or more in the pure copper powder exceeds 40%, it is considered that the formation of the network-like pure copper phase starts to be locally inhibited and the thermal conductivity starts to decrease. Therefore, it was confirmed that the ratio of the powder having a size of 50 μm or more in the pure copper powder is preferably 40% or less.
[0048]
By comparing Sample Nos. 13 and 47 to 50, the influence of the ratio of the powder having a particle size of 50 μm or more on the thermal conductivity and the hardness on the iron-based alloy powder can be understood. FIG. 11 is a graph of this.
From these results, when the proportion of the iron-based alloy powder having a particle diameter of 50 μm or more is 40% or more, a substantially constant thermal conductivity is exhibited, but when it is less than 40%, a slight decrease in the thermal conductivity is observed. This is considered to be because the iron-based alloy powder was shifted to the fine powder side, easily diffused with the matrix, and the thermal conductivity was lowered. Therefore, it was confirmed that the ratio of the powder having a diameter of 50 μm or more in the iron-based alloy powder is preferably 40% or more.
[0049]
【The invention's effect】
The copper-based low thermal expansion high thermal conductive member according to the present invention has a coefficient of thermal expansion up to 100 ° C. of 6 × 10 in a precipitation hardening type copper alloy matrix or a matrix comprising a precipitation hardening type copper alloy phase and a pure copper phase. -6 / K or less is dispersed in a mass ratio of 5 to 60%. Thereby, the iron-based alloy powder slightly diffused into the matrix strongly suppresses the thermal expansion of the matrix, combines high thermal conductivity and a low coefficient of thermal expansion, and is excellent in hardness and strength, and is inexpensive. And excellent properties such as high workability.
Further, the copper-based low thermal expansion high thermal conductive member according to the present invention does not require separate solution treatment and aging treatment, and can be easily manufactured by simple steps.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the amount of an iron-based alloy powder added to a precipitation hardening type copper alloy powder and the thermal conductivity and the coefficient of thermal expansion.
FIG. 2 is a graph showing the relationship between the ratio of pure copper powder in the matrix powder and the thermal conductivity, with the addition amount of the iron-based alloy powder kept constant.
FIG. 3 is a graph showing the relationship between the ratio of the pure copper powder in the matrix powder and the hardness when the addition amount of the iron-based alloy powder is constant.
FIG. 4 is a graph showing a relationship between a sintering temperature, a thermal conductivity, and a thermal expansion coefficient when a blending amount of a precipitation hardening type copper alloy powder and an iron-based alloy powder is fixed.
FIG. 5 is a graph showing the relationship between the sintering temperature and the hardness when the blending amounts of the precipitation hardening type copper alloy powder and the iron-based alloy powder are kept constant.
FIG. 6 is a graph showing a comparison of thermal conductivity when the type of iron-based alloy powder is changed for various precipitation hardening type copper alloys.
FIG. 7 is a graph showing a comparison of thermal expansion coefficients when the type of iron-based alloy powder is changed for various precipitation hardening type copper alloys.
FIG. 8 is a graph showing a comparison of hardness when the type of iron-based alloy powder is changed with respect to various precipitation hardening type copper alloys.
FIG. 9 is a graph showing the effect of the proportion of powder having a particle size of 50 μm or more in the precipitation hardening type copper alloy powder on thermal conductivity and hardness.
FIG. 10 is a graph showing the effect of the proportion of powder having a size of 50 μm or more in pure copper powder on thermal conductivity and hardness.
FIG. 11 is a graph showing the effect of the proportion of powder having a particle size of 50 μm or more in the iron-based alloy powder on thermal conductivity and hardness.
Claims (8)
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| JP2003123423A JP3909037B2 (en) | 2003-04-28 | 2003-04-28 | Manufacturing method of low thermal expansion and high thermal conductive member |
| KR1020040028682A KR100594602B1 (en) | 2003-04-28 | 2004-04-26 | Method for producing copper based material of low thermal expansion and high thermal conductivity |
| US10/832,247 US7378053B2 (en) | 2003-04-28 | 2004-04-27 | Method for producing copper-based material with low thermal expansion and high heat conductivity |
| DE102004020833A DE102004020833B4 (en) | 2003-04-28 | 2004-04-28 | Low thermal expansion and high thermal conductivity copper based material and method of making same |
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| US10981226B2 (en) | 2016-10-25 | 2021-04-20 | Daihen Corporation | Copper alloy powder, method of producing additively-manufactured article, and additively-manufactured article |
| CN114892040A (en) * | 2022-06-02 | 2022-08-12 | 浙江大学 | Design method and preparation method of high-strength and high-conductivity copper alloy |
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