JP4247339B2

JP4247339B2 - Sn-coated member and manufacturing method thereof

Info

Publication number: JP4247339B2
Application number: JP2002011304A
Authority: JP
Inventors: 宏人成枝; 芳典鈴木
Original assignee: Dowa Metaltech Co Ltd
Current assignee: Dowa Metaltech Co Ltd
Priority date: 2002-01-21
Filing date: 2002-01-21
Publication date: 2009-04-02
Anticipated expiration: 2022-01-21
Also published as: JP2003213486A

Description

【０００１】
【発明の属する技術分野】
本発明は、銅または銅合金をＳｎで被覆したＳｎ被覆部材およびその製造方法に関し、特に、コネクタの多極化に伴う挿入力の低減を必要とする自動車用の多極コネクタ端子や、ヒューズブロック、ジャンクションブロックおよびリレーブロックに用いられるバスバーや、ＦＦＣおよびＦＰＣなどのフラットケーブルや、パソコンなどの接続用コネクタ端子などに用いられるＳｎ被覆部材およびその製造方法に関する。
【０００２】
【従来の技術】
従来、自動車用や民生用のコネクタのうち、一つの端子における接触力が１〜１００Ｎのコネクタでは、接触信頼性の観点から厚さ０．８〜１０μｍ程度のＳｎやＳｎ−Ｐｂで被覆した銅や銅合金からなる部材が使用されている。これは、ＳｎやＳｎ−Ｐｂが軟らかく、端子挿入時に酸化したＳｎやＳｎ−Ｐｂの最表層が削られて新鮮な金属面同士の結合が得られるからである。また、光沢のある外観を得るために、表層の状態が平滑になるようにしている。
【０００３】
【発明が解決しようとする課題】
しかしながら、端子挿入時に削られる軟質のＳｎは、雄雌端子間で相互に凝着し、端子挿入時の大きな摩擦抵抗となる。端子には、電気的接続を確実にするためにリブやインデントなどの突起が形成されており、その先端が他方の端子、バスバー、タブ、フラットケーブルなどの表面に密に接触する構造になっていることが多いが、端子挿入時には、Ｓｎの凝着だけでなく、掘り起しによる摩擦抵抗によっても端子挿入力が増加する。
【０００４】
また、表面が平滑なＳｎ被覆材は、Ｓｎを薄くした場合でも、端子挿入時に摩擦抵抗となる軟質のＳｎが連続して掘り起こされるため、また掘り起こされたＳｎが嵌合部に凝着するため、表面の摩擦係数が大きく、端子単体の挿入力が大きくなる。端子挿入力が大きくなると、複数の端子で構成されるコネクタの挿入力も大きくなる。そのため、コネクタの多極化によって、組立て作業者の負担が増加する。
【０００５】
コネクタの挿入力を低減させるためには、端子の接触力を小さくするか、摩擦係数を小さくする必要がある。しかし、接触力を小さくすることは、素材の応力緩和や表層の微摺動摩擦により端子本来の性能である確実な電気的接続ができなくなる可能性が高くなるため好ましくない。そのため、摩擦係数を小さくすることが重要になる。
【０００６】
したがって、本発明は、このような従来の問題点に鑑み、確実な電気的接続を提供でき且つ摩擦係数が小さいＳｎ被覆部材およびその製造方法を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明者らは、上記課題を解決するために鋭意研究した結果、銅または銅合金の表面に、８０重量％以上のＳｎを含有し且つ平均の幅が５乃至１００μｍで平均の高さが０．１乃至１．０μｍの島状凸部を形成することにより、確実な電気的接続を提供でき且つ摩擦係数が小さいＳｎ被覆部材を提供することができることを見出し、本発明を完成するに至った。
【０００８】
すなわち、本発明によるＳｎ被覆部材は、銅または銅合金の表面に、８０重量％以上のＳｎを含有し且つ平均の幅が５乃至１００μｍで平均の高さが０．１乃至１．０μｍの島状凸部が形成されていることを特徴とする。このＳｎ被覆部材において、島状凸部の面積と銅または銅合金の表面上の島状凸部以外の平坦部との面積の比（島状凸部の面積／平坦部の面積）が０．１乃至２であるのが好ましい。また、平坦部の表層部にＳｎ含有層が形成されているのが好ましい。この場合、銅または銅合金とＳｎ含有層との間にＮｉ含有層が形成されているのがさらに好ましい。さらに、島状凸部の露出面と銅または銅合金の表面上の島状凸部以外の平坦部との交線上における島状凸部の接線と、平坦部の表面とのなす角θが、０°＜θ＜９０°であるのが好ましい。
【０００９】
また、本発明によるＳｎ被覆部材の製造方法は、銅または銅合金の表面を、厚さ０．２乃至１．０μｍの８０重量％以上のＳｎを含有する層で被覆した後に、２３０乃至８００℃の温度で１乃至３００秒間の溶融処理条件において溶融処理の温度と時間を制御して溶融処理を行うことによって、銅または銅合金の表面に、８０重量％以上のＳｎを含有し且つ平均の幅が５乃至１００μｍで平均の高さが０．１乃至１．０μｍの島状凸部を形成することを特徴とする。このＳｎ被覆部材の製造方法において、Ｓｎを含有する層で被覆する前に、銅または銅合金の表面を、Ｓｎ、Ｃｕ、Ｎｉ、Ｆｅ、Ｚｎ、Ｃｏ、Ａｕ、Ａｇ、ＰｂおよびＰのうちの少なくとも１種以上の元素を含み且つ厚さ０．０５乃至３μｍの単層または複層の下地層で被覆するのが好ましい。
【００１０】
また、本発明によるＳｎ被覆部材の製造方法は、銅または銅合金の表面を、厚さ０．０５乃至３μｍのＮｉを含有する層で被覆し、その上を厚さ０．０５乃至３μｍのＣｕを含有する層で被覆し、その上を厚さ０．２乃至１．０μｍの８０重量％以上のＳｎを含有する層で被覆した後に、２３０乃至８００℃の温度で１〜３００秒間の溶融処理条件において溶融処理の温度と時間を制御して溶解処理を行うことによって、銅または銅合金の表面に、８０重量％以上のＳｎを含有し且つ平均の幅が５乃至１００μｍで平均の高さが０．１乃至１．０μｍの島状凸部を形成することを特徴とする。
【００１１】
上記のＳｎ被覆部材の製造方法において、島状凸部の面積と銅または銅合金の表面上の島状凸部以外の平坦部との面積の比（島状凸部の面積／平坦部の面積）が０．１乃至２であるのが好ましい。さらに、島状凸部の露出面と銅または銅合金の表面上の島状凸部以外の平坦部との交線上における島状凸部の接線と、平坦部の表面とのなす角θが、０°＜θ＜９０°であるのが好ましい。
【００１２】
【発明の実施の形態】
本発明によるＳｎ被覆部材の製造方法の実施の形態では、めっきや蒸着などにより、銅または銅合金からなる素材を、必要に応じて厚さ０．０５〜３μｍのＳｎ、Ｃｕ、Ｎｉ、Ｆｅ、Ｚｎ、Ｃｏ、Ａｕ、Ａｇ、ＰｂおよびＰのうちの少なくとも１種以上の元素を含む単層または複層の下地層で被覆し、その上を厚さ０．１〜２μｍのＳｎ含有層で被覆し、その後、処理条件を制御して溶融処理を行うことによって、表面に幅５〜３００μｍ、高さ０．１〜１．５μｍの島状凸部を形成する。
【００１３】
なお、本明細書中において、Ｓｎ含有層とは、Ｓｎの他にＰｂ、Ｚｎ、ＣｕおよびＡｇのうちの１種以上を０〜２０重量％含有するＳｎ含有材料からなる層をいう。Ｓｎの含有量を８０重量％以上とするのは、Ｓｎの含有量が８０重量％未満であると、溶融処理時の島状凸部の形成が難しくなるからである。
【００１４】
形成された島状凸部は、主に溶融処理によって凝集したＳｎ含有材料からなる。この島状凸部の高さ、幅および面積を制御することにより、軟質のＳｎ含有層の掘り起こし量や凝着量が減少し、且つ少量のＳｎ含有材料が低せん断抵抗であることを利用した潤滑作用を示すために、摩擦係数が小さくなる。島状凸部以外の平坦部は、厚さ１μｍ以下のＳｎ含有層や、Ｃｕ_６Ｓｎ_５、Ｃｕ_３Ｓｎ、Ｎｉ_３Ｓｎ_４、Ｎｉ_３Ｓｎなどの合金層、または下地金属の層になっている。そのため、試験力０．０９８Ｎ以下でビッカース硬さを測定すると、島状凸部のビッカース硬さは５〜２００の値になり、島状凸部以外のビッカース硬さは島状凸部の値よりも高くなる。
【００１５】
本発明による島状凸部を有するＳｎ被覆部材を使用する場合、端子やバスバーなどの接触する片面側に使用しても摩擦係数の低減効果があるが、接触する両面に使用すると摩擦力の低減効果はさらに高まる。
【００１６】
図１に示す島状凸部１と平坦部２とのなす角（島状凸部１の露出面と平坦部２の交線上における島状凸部１の接線と平坦部２の表面とのなす角）θは、０°＜θ＜９０°にするのが好ましい。摩擦係数を小さくするためには、掘り起こしの抵抗を小さくする必要があり、角θは９０°未満にした方がよいからである。ただし、０°では島状凸部が形成されないため、０°＜θ＜９０°とする。
【００１７】
また、島状凸部の幅を５〜３００μｍ、高さを０．１〜１．５μｍにするのが好ましい。溶融処理による島状凸部の形成において、幅を５μｍ未満、高さを０．１μｍ未満に制御することは難しく、また、幅が３００μｍを超えるか、高さが１．５μｍを超えると、端子挿入時の掘り起こし量が多くなり、摩擦力の低減効果が小さくなるからである。したがって、島状凸部の幅を５〜３００μｍ、高さを０．０５〜１．５μｍに制御するのが好ましく、幅を５〜１００μｍ、高さを０．１〜１．０μｍに制御するのがさらに好ましい。なお、本明細書中において、「幅」の方向は、素材となる銅または銅合金の圧延方向と垂直な方向（図２において線Ａ−Ｂの方向）をいい、「高さ」の方向は、素材となる銅または銅合金の圧延面の法線方向をいう。
【００１８】
また、島状凸部の面積と平坦部の面積の比（島状凸部の面積／平坦部の面積）が０．０５〜４になるように溶融処理条件を制御するのが好ましい。面積比が０．０５未満ではＳｎ含有材料の潤滑作用が低下し、摩擦力の低減効果が小さくなり、面積比が４を超えると軟らかいＳｎ含有層の掘り起こし量が多くなって摩擦力の低減効果が小さくなるからである。したがって、島状凸部の面積と平坦部の面積の比が０．０５〜４になるように溶融処理条件を制御するのが好ましく、０．１〜２になるように溶融処理条件を制御するのがさらに好ましい。
【００１９】
また、溶融処理前のＳｎ含有層の厚さを０．１〜２μｍの範囲にするのが好ましい。０．１μｍ未満ではＳｎ含有材料の量が不足し、溶融処理を行っても島状凸部を形成させることが難しく、２μｍを超えると溶融処理時に溶融したＳｎ含有材料が粗大に凝集し易くなり、結果として島状凸部も粗大になり、摩擦力の低減効果が小さくなるからである。したがって、溶融処理前のＳｎ含有層の厚さを０．１〜２μｍの範囲にするのが好ましく、０．２〜１．０μｍの範囲にするのがさらに好ましい。
【００２０】
また、Ｓｎ含有層の下に、厚さ０．０５〜３μｍのＳｎ、Ｃｕ、Ｎｉ、Ｆｅ、Ｚｎ、Ｃｏ、Ａｕ、Ａｇ、ＰｂおよびＰのうちの少なくとも１種以上の元素を含む単層または複層の下地層を設けるのが好ましい。この理由を以下に説明する。素地中のＣｕやＺｎなどは、Ｓｎ含有材料と容易に相互拡散して合金層を形成する。表層のＳｎ含有材料を島状に形成することにより、Ｓｎ含有材料が平滑な場合よりもＳｎ含有材料の全量が合金層になるのを遅らせることができるが、それでも経時変化により合金層へ移行してしまう。Ｓｎ含有材料が合金化すると、最表層ではＳｎ含有材料以外の酸化物も形成され、また、軟らかいＳｎ含有層がないことにより酸化物の除去も難しくなることから、接触信頼性の低下およびはんだ付け性の低下など、端子としての性能も悪化する。したがって、Ｓｎ含有層だけでは耐熱性などの信頼性が不足する場合には、素材成分とＳｎ含有層とが合金化するのを防止するために、上記の下地層を設けるのが好ましい。また、Ｓｎ含有層の下に、ＮｉやＮｉ−Ｐなどの被覆層や、表層のＳｎ含有材料と合金化したＣｕ−ＳｎやＮｉ−Ｓｎなどのビッカース硬さが１００を超える硬い層を導入すると、摩擦力をさらに低減させる効果がある。
【００２１】
下地層やＳｎ含有層の形成には、コスト面や厚さの制御に優れる電気めっきを用いるのが好ましいが、無電解めっき、蒸着または溶融金属浸漬処理などを用いてもよい。また、Ｓｎ含有層で被覆した後、溶融処理までの時間が空くと、表面の酸化膜が成長し、溶融処理時の溶融したＳｎ含有材料の流れが悪くなり、島状凸部の形成が難しくなるため、Ｓｎ含有層を形成後、溶融処理までの時間はできるだけ短い方がよい。Ｓｎ含有層を形成後１時間以内に溶融処理することが好ましいが、屋内で管理する場合、３日程度までは問題はなく、１週間を超えると島状凸部を均一に形成できなくなる。ただし、このような場合でも、溶融処理直前に酸洗などの活性化処理を行えば、再び島状凸部を形成することが可能になる。
【００２２】
溶融処理は、バーナー炉、電気炉、熱風循環炉、マッフル炉、通電焼鈍装置などにより行うことができるが、熱により表層のＳｎ含有材料を溶融することができれば、例えば、レーザーや赤外線などを使用してもよい。
【００２３】
島状凸部を形成するためには、溶融処理の温度と時間を制御することが重要である。Ｓｎ含有材料は、Ｓｎ含有材料で被覆した銅または銅合金の表面温度が融点（Ｓｎ含有材料が１００％のＳｎであれば２３２℃）を超える時に溶融し、下地被覆層や素材と接する側では拡散層を形成する。表面側では、溶融初期には平滑な面を保つが、それ以上に熱量が加えられると、溶融したＳｎ含有材料の凝集が始まり、分散した島状凸部を形成する。さらに熱量が加えられると、島状凸部が粗大になるか、表層まで拡散層が成長する。本発明による島状凸部を形成するためには、この熱量の制御が重要になる。熱量の制御方法は各処理設備によって異なるが、バーナー炉、電気炉などの炉で処理する場合は、炉内雰囲気温度を２３０〜８００℃、炉内保持（通過）時間を１〜３００秒に制御するのが好ましい。Ｓｎ含有材料が平滑になる条件がわかっている場合は、その条件よりも雰囲気温度を上げるか保持時間を長くすることによって、島状凸部を形成することができる。
【００２４】
また、島状凸部を形成するためには、溶融処理後に冷却することも重要である。冷却の媒体は固体、液体、気体のいずれでもよいが、１分以内に５０℃以下に冷却できる能力が必要である。
【００２５】
以上の処理によって形成された幅５〜３００μｍ、高さ０．１〜１．５μｍで、且つ島状凸部の面積と平坦部の面積の比が０．０５〜４になる島状凸部を有するＳｎ被覆部材は、表層の摩擦係数が小さく、端子、バスバー、フラットケーブルなどに使用した場合の挿入力を低減させることができる。
【００２６】
【実施例】
以下、本発明によるＳｎ被覆部材およびその製造方法の実施例について詳細に説明する。
【００２７】
［実施例１］
素材として、銅中に１ｗｔ％のＮｉ、０．９ｗｔ％のＳｎ、０．０５ｗｔ％のＰを含有する厚さ０．２５ｍｍ、ビッカース硬さ１７０の銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上に、Ｓｎの他にＰｂ、Ｚｎ、ＣｕおよびＡｇのうちの１種以上を０〜２０重量％含有するＳｎ含有材料からなる被覆層を形成した。この被覆層は、コスト的に有利で厚さの制御も比較的容易な電気めっきを使用して、硫酸塩浴を用いてめっきすることにより形成した。
【００２８】
電気めっきを行った後に、バーナー炉を使用して、炉内温度６００℃、炉内通過時間８秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００２９】
この実施例で作製したＳｎ被覆部材について、被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。
【００３０】
被覆層の厚さは、この実施例と同じ条件でめっきした後に溶融処理していないサンプルを別途作製し、蛍光Ｘ線膜厚計を用いて測定した。その結果、Ｓｎ含有材料からなる被覆層の厚さは０．４μｍであった。
【００３１】
島状凸部の平均の幅は、金属顕微鏡でめっき表面を２００倍に拡大し、ノマルスキー微分干渉観察した結果に基づいて実測した。島状凸部の面積の測定は点算法で行った。その結果、島状凸部の平均の幅は２０μｍ、面積比（島状凸部の面積／平坦部の面積）は０．１２であった。
【００３２】
島状凸部の平均の高さは、３次元レーザー顕微鏡を用いて測定した。その結果、島状凸部の平均の高さは０．４μｍであった。また、島状凸部と平坦部のなす角θも３次元レーザー顕微鏡を用いて測定し、いずれも０°＜θ＜９０°に収まっていることを確認した。
【００３３】
ビッカース硬さは、試験力０．０９８Ｎで測定した。測定位置は付属のモニターで確認し、島状凸部においてはその中央部で測定した。その結果、島状凸部のビッカース硬さは１３５であり、島状凸部以外の部分のビッカース硬さは１７０であった。
【００３４】
また、この実施例で作製したＳｎ被覆部材について、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。
【００３５】
摩擦係数は、図２に示すように、試験材（下材）（幅５０ｍｍ×長さ３００ｍｍ）７を水平台９に固定し、その上に質量１５Ｎの重錘８を貼り付けた同一の試験材（上材）６を載せ、プーリー１０を介してロードセル１１により１００ｍｍ／ｍｉｎの速度で引いて摩擦力を測定し、その摩擦力に基づいて、｛摩擦係数＝水平方向に加わる力／垂直方向の力｝から計算した。また、試験材の端面のバリの影響を除くために、試験材（上材）６には、Ｒ＝１ｍｍのインデントを３点付けた。その結果、摩擦係数は０．２０であった。
【００３６】
高温保持後の接触抵抗値は、大気雰囲気中において試験材を１６０℃で１２０時間保持した後に、電気接点シミュレータとマイクロオームメーターを利用し、電流１０ｍＡ、Ａｕプローブの最大摺動接触荷重０．４９Ｎで測定した。その結果、高温保持後の接触抵抗値は５ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。
【００３７】
耐熱変色試験は、大気雰囲気中において試験材を１８０℃で１時間保持した後に表面の変色を目視で観察することによって行った。その結果、変色しなかったことが観察された。
【００３８】
［実施例２］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上にＮｉからなる下地層を形成し、その上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。これらの下地層および被覆層は、実施例１と同様に電気めっきを使用して、下地のＮｉはスルファミン酸ニッケル浴、表層のＳｎ含有材料は硫酸塩浴を用いてめっきすることにより形成した。
【００３９】
電気めっきを行った後に、バーナー炉を使用して、炉内温度６００℃、炉内通過時間８秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００４０】
この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、下地層および被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｎｉからなる下地層の厚さは０．５μｍであり、Ｓｎ含有材料からなる被覆層の厚さは０．４μｍであった。また、島状凸部の平均の幅は２５μｍ、面積比（島状凸部の面積／平坦部の面積）は０．１５であった。また、島状凸部の平均の高さは０．４μｍであり、島状凸部と平坦部とのなす角θがいずれも０°＜θ＜９０°に収まっていることを確認した。さらに、島状凸部のビッカース硬さは１２５であり、島状凸部以外の部分のビッカース硬さは１６０であった。
【００４１】
また、この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．２２であり、高温保持後の接触抵抗値は５ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００４２】
［実施例３］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上にＮｉからなる下地層を形成し、その上にＣｕからなる下地層を形成し、さらにその上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。これらの下地層および被覆層は、実施例１と同様に電気めっきを使用して、下地のＮｉはスルファミン酸ニッケル浴、Ｃｕは硫酸銅浴、表層のＳｎ含有材料は硫酸塩浴を用いてめっきすることにより形成した。
電気めっきを行った後に、バーナー炉を使用して、炉内温度６００℃、炉内通過時間８秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００４３】
この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、下地層および被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。なお、下地層の厚さは、Ｎｉについては実施例２と同様に蛍光Ｘ線膜厚計を使用し、Ｃｕについては電解式膜厚計を使用して測定した。その結果、Ｎｉからなる下地層の厚さは０．３μｍ、Ｃｕからなる下地層の厚さは０．２μｍ、Ｓｎ含有材料からなる被覆層の厚さは０．５μｍであった。また、島状凸部の平均の幅は５０μｍ、面積比（島状凸部の面積／平坦部の面積）は０．３０であった。また、島状凸部の平均の高さは０．３μｍであり、島状凸部と平坦部とのなす角θがいずれも０°＜θ＜９０°に収まっていることを確認した。さらに、島状凸部のビッカース硬さは１２５であり、島状凸部以外の部分のビッカース硬さは１６５であった。
【００４４】
また、この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．２３であり、高温保持後の接触抵抗値は１ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００４５】
［実施例４］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。この被覆層は、実施例１とめっき時間が異なる以外は、実施例１と同様に、電気めっきを使用して、硫酸塩浴を用いてめっきすることにより形成した。
【００４６】
電気めっきを行った後に、バーナー炉を使用して、炉内温度６００℃、炉内通過時間８秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００４７】
この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｓｎ含有材料からなる被覆層の厚さは０．７μｍであった。また、島状凸部の平均の幅は２５μｍ、面積比（島状凸部の面積／平坦部の面積）は０．１２であった。また、島状凸部の平均の高さは０．２μｍであり、島状凸部と平坦部とのなす角θがいずれも０°＜θ＜９０°に収まっていることを確認した。さらに、島状凸部のビッカース硬さは１３０であり、島状凸部以外の部分のビッカース硬さは１７５であった。
【００４８】
また、この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．２２であり、高温保持後の接触抵抗値は４ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００４９】
［実施例５］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。この被覆層は、実施例１とめっき時間が異なる以外は、実施例１と同様に、電気めっきを使用して、硫酸塩浴を用いてめっきすることにより形成した。
【００５０】
電気めっきを行った後に、バーナー炉を使用して、炉内温度６００℃、炉内通過時間９秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００５１】
この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｓｎ含有材料からなる被覆層の厚さは０．７μｍであった。また、島状凸部の平均の幅は５０μｍ、面積比（島状凸部の面積／平坦部の面積）は０．１８であった。また、島状凸部の平均の高さは０．４μｍであり、島状凸部と平坦部とのなす角θがいずれも０°＜θ＜９０°に収まっていることを確認した。さらに、島状凸部のビッカース硬さは１１０であり、島状凸部以外の部分のビッカース硬さは１７５であった。
【００５２】
また、この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．２４であり、高温保持後の接触抵抗値は４ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００５３】
［実施例６］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上にＮｉからなる下地層を形成し、その上にＣｕからなる下地層を形成し、さらにその上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。これらの下地層および被覆層は、実施例３とめっき時間が異なる以外は、実施例３と同様に、電気めっきを使用して、下地のＮｉはスルファミン酸ニッケル浴、Ｃｕは硫酸銅浴、表層のＳｎ含有材料は硫酸塩浴を用いてめっきすることにより形成した。
【００５４】
電気めっきを行った後に、バーナー炉を使用して、炉内温度６３０℃、炉内通過時間８秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００５５】
この実施例で作製したＳｎ被覆部材について、実施例３と同様の方法により、下地層および被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｎｉからなる下地層の厚さは０．５μｍ、Ｃｕからなる下地層の厚さは０．４μｍ、Ｓｎ含有材料からなる被覆層の厚さは１．０μｍであった。また、島状凸部の平均の幅は４０μｍ、面積比（島状凸部の面積／平坦部の面積）は０．２８であった。また、島状凸部の平均の高さは０．７μｍであり、島状凸部と平坦部とのなす角θがいずれも０°＜θ＜９０°に収まっていることを確認した。さらに、島状凸部のビッカース硬さは１０５であり、島状凸部以外の部分のビッカース硬さは１５５であった。
【００５６】
また、この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．２７であり、高温保持後の接触抵抗値は１ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００５７】
［実施例７］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。この被覆層は、実施例１とめっき時間が異なる以外は、実施例１と同様に、電気めっきを使用して、硫酸塩浴を用いてめっきすることにより形成した。
【００５８】
電気めっきを行った後に、バーナー炉を使用して、炉内温度６３０℃、炉内通過時間８秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００５９】
この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｓｎ含有材料からなる被覆層の厚さは１．２μｍであった。また、島状凸部の平均の幅は６０μｍ、面積比（島状凸部の面積／平坦部の面積）は０．４９であった。また、島状凸部の平均の高さは０．６μｍであり、島状凸部と平坦部とのなす角θがいずれも０°＜θ＜９０°に収まっていることを確認した。さらに、島状凸部のビッカース硬さは１０５であり、島状島状凸部以外の部分のビッカース硬さは１６０であった。
【００６０】
また、この実施例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．２８であり、高温保持後の接触抵抗値は３ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００６１】
［比較例１］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。この被覆層は、実施例１とめっき時間が異なる以外は、実施例１と同様に、電気めっきを使用して、硫酸塩浴を用いてめっきすることにより形成した。
【００６２】
電気めっきを行った後に、バーナー炉を使用して、実施例１よりも熱量を過剰に与える溶融処理条件、すなわち、炉内温度６００℃、炉内通過時間１０秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００６３】
この比較例で作製したＳｎ被覆部材について、実施例１と同様の方法により、被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｓｎ含有材料からなる被覆層の厚さは０．１μｍであった。また、溶融処理後にＳｎ含有材料が全て拡散し、島状凸部が形成されていなかった。さらに、島状凸部以外の部分のビッカース硬さは１９０であった。
【００６４】
また、この比較例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．２３であり、高温保持後の接触抵抗値は１２ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は２ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００６５】
［比較例２］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。この被覆層は、実施例１とめっき時間が異なる以外は、実施例１と同様に、電気めっきを使用して、硫酸塩浴を用いてめっきすることにより形成した。
【００６６】
電気めっきを行った後に、バーナー炉を使用して、めっき面が全て平滑なＳｎ含有層で覆われる溶融処理条件、すなわち、炉内温度６００℃、炉内通過時間１０秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００６７】
この比較例で作製したＳｎ被覆部材について、実施例１と同様の方法により、被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｓｎ含有材料からなる被覆層の厚さは０．７μｍであった。また、溶融処理後にめっき面が全て平滑なＳｎ含有層で覆われ、島状凸部が形成されていなかった。さらに、Ｓｎ含有層で覆われた部分のビッカース硬さは１００であった。
【００６８】
また、この比較例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．３２であり、高温保持後の接触抵抗値は３ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００６９】
［比較例３］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。この被覆層は、実施例１とめっき時間が異なる以外は、実施例１と同様に、電気めっきを使用して、硫酸塩浴を用いてめっきすることにより形成した。
【００７０】
電気めっきを行った後に、バーナー炉を使用して、実施例４および５よりも熱量を過剰に与える溶融処理条件、すなわち、炉内温度６００℃、炉内通過時間１２秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００７１】
この比較例で作製したＳｎ被覆部材について、実施例１と同様の方法により、被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｓｎ含有材料からなる被覆層の厚さは０．７μｍであった。また、島状凸部の平均の幅は４００μｍ、面積比（島状凸部の面積／平坦部の面積）は５．６７であった。また、島状凸部の平均の高さは１．６μｍであり、島状凸部と平坦部とのなす角θがいずれも０°＜θ＜９０°に収まっていることを確認した。さらに、島状凸部のビッカース硬さは７５であり、島状凸部以外の部分のビッカース硬さは１５５であった。
【００７２】
また、この比較例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．３１であり、高温保持後の接触抵抗値は５ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色していたことが観察された。
【００７３】
［比較例４］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上にＮｉからなる下地層を形成し、その上にＣｕからなる下地層を形成し、さらにその上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。これらの下地層および被覆層は、実施例３とめっき時間が異なる以外は、実施例３と同様に、電気めっきを使用して、下地のＮｉはスルファミン酸ニッケル浴、Ｃｕは硫酸銅浴、表層のＳｎ含有材料は硫酸塩浴を用いてめっきすることにより形成した。
【００７４】
電気めっきを行った後に、バーナー炉を使用して、めっき面が全て平滑なＳｎ含有層で覆われる溶融処理条件、すなわち、炉内温度６３０℃、炉内通過時間６秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００７５】
この比較例で作製したＳｎ被覆部材について、実施例３と同様の方法により、下地層および被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｎｉからなる下地層の厚さは０．５μｍ、Ｃｕからなる下地層の厚さは０．４μｍ、Ｓｎ含有材料からなる被覆層の厚さは１．０μｍであった。また、溶融処理後にめっき面が全て平滑なＳｎ含有層で覆われ、島状凸部が形成されていなかった。さらに、Ｓｎ含有層で覆われた部分のビッカース硬さは９５であった。
【００７６】
また、この比較例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．４０であり、高温保持後の接触抵抗値は１ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００７７】
［比較例５］
素材として、実施例１と同じ銅合金条を用意し、銅合金の表面を電解脱脂と酸洗で活性化した後、その上に実施例１と同じＳｎ含有材料からなる被覆層を形成した。この被覆層は、実施例１とめっき時間が異なる以外は、実施例１と同様に、電気めっきを使用して、硫酸塩浴を用いてめっきすることにより形成した。
【００７８】
電気めっきを行った後に、バーナー炉を使用して、めっき面が全て平滑なＳｎ含有層で覆われる溶融処理条件、すなわち、炉内温度６３０℃、炉内通過時間６秒、還元雰囲気で溶融処理を行い、その後、水とブロワーを併用して冷却して、Ｓｎ被覆部材を作製した。
【００７９】
この比較例で作製したＳｎ被覆部材について、実施例１と同様の方法により、被覆層の厚さ、島状凸部の平均の幅および高さ、面積比、ビッカース硬さを測定した。その結果、Ｓｎ含有材料からなる被覆層の厚さは１．２μｍであった。また、溶融処理後にめっき面が全て平滑なＳｎ含有層で覆われ、島状凸部が形成されていなかった。さらに、Ｓｎ含有層で覆われた部分のビッカース硬さは７５であった。
【００８０】
また、この比較例で作製したＳｎ被覆部材について、実施例１と同様の方法により、摩擦係数および高温保持後の接触抵抗値を測定するとともに、耐熱変色試験を行った。その結果、摩擦係数は０．４６であり、高温保持後の接触抵抗値は２ｍΩであった。なお、耐熱試験前（初期状態）の接触抵抗値は１ｍΩであった。また、耐熱変色試験において、変色しなかったことが観察された。
【００８１】
上述したように、実施例１〜７のＳｎ被覆部材は、いずれも摩擦係数が小さく、高温保持後の接触抵抗も１０ｍΩ未満と小さく、高温保持後の表面も変色していない。したがって、本発明によるＳｎ被覆部材は、電気接続を行う端子、バスバー、フラットケーブルなどに使用するのに適しており、特に、挿入力の低減が必要な多極コネクタ端子、産業機械や民生機器などの接続用コネクタ端子などに使用するのに極めて適している。
【００８２】
また、銅または銅合金の素材をＮｉとＣｕの下地層で被覆した実施例３および実施例６のＳｎ被覆部材は、耐熱試験後の接触抵抗の増加が小さく、特に耐熱性を必要とする自動車のエンジンルーム内で使用されるコネクタなどに極めて有用である。
【００８３】
これに対し、溶融処理で被覆したＳｎ含有材料の全てをＣｕ−Ｓｎ拡散させ、表面に島状凸部を形成しなかった比較例１のＳｎ被覆部材は、接触抵抗の面においてかなり劣っている。
【００８４】
同じめっき構成で比較すると、Ｓｎ含有層の厚さが０．７μｍで表面が平滑な比較例２のＳｎ被覆部材、および過溶融処理により島状凸部が粗大になっている比較例３のＳｎ被覆部材は、実施例４および実施例５のＳｎ被覆部材と比較して摩擦係数が大きくなっている。さらに、比較例３のＳｎ被覆部材は、表面の変色の点でも劣っている。また、表面が平滑な比較例４および比較例５のＳｎ被覆部材も同様に、同じめっき構成である実施例６および実施例７のＳｎ被覆部材よりも摩擦係数が大きくなっている。
【００８５】
なお、実施例１〜７および比較例１〜５についての結果をまとめて表１および表２に示す。
【００８６】
【表１】

【００８７】
【表２】

【００８８】
なお、実施例では素材として銅合金を使用したが、銅を使用しても上述した効果と同様の効果を得ることができる。
【００８９】
【発明の効果】
上述したように、本発明によれば、摩擦係数が低く、且つ高温保持後の接触抵抗、耐変色性などに優れたＳｎ被覆部材を提供することができ、自動車用の多極コネクタ端子、バスバー、産業機械および民生機器などのコネクタ端子など、挿入力の低減と長期接続時の電気的接続の信頼性が要求される電気・電子部品用材料として優れたＳｎ被覆部材を提供することができる。
【図面の簡単な説明】
【図１】実施例において作製したＳｎ被覆部材の島状凸部を示す摸式図であり、図１（ａ）は平面図、図１（ｂ）は図１（ａ）のＡ−Ｂ線断面図。
【図２】実施例および比較例における摩擦係数の測定方法を示す図。
【符号の説明】
１島状凸部
２平坦部
６試験材（上材）
７試験材（下材）
８重錘（１５Ｎ）
９水平台
１０プーリー
１１ロードセル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a Sn-coated member in which copper or a copper alloy is coated with Sn, and a method for manufacturing the same, and more particularly to a multipolar connector terminal for automobiles, a fuse block, and a junction that require a reduction in insertion force due to multipolarization of connectors. The present invention relates to a Sn covering member used for bus bars used for blocks and relay blocks, flat cables such as FFC and FPC, connector terminals for personal computers and the like, and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, among connectors for automobiles and consumer use, a connector having a contact force of 1 to 100 N at one terminal is coated with Sn or Sn-Pb having a thickness of about 0.8 to 10 μm from the viewpoint of contact reliability. A member made of copper alloy is used. This is because Sn or Sn-Pb is soft and the outermost layer of Sn or Sn-Pb oxidized at the time of terminal insertion is scraped to obtain a bond between fresh metal surfaces. Further, in order to obtain a glossy appearance, the surface layer is made smooth.
[0003]
[Problems to be solved by the invention]
However, the soft Sn that is shaved when the terminal is inserted adheres to each other between the male and female terminals, resulting in a large frictional resistance when the terminal is inserted. The terminal has protrusions such as ribs and indents to ensure electrical connection, and its tip is in close contact with the surface of the other terminal, bus bar, tab, flat cable, etc. In many cases, when inserting a terminal, the terminal insertion force increases not only by Sn adhesion but also by frictional resistance caused by digging.
[0004]
In addition, even when Sn is thinned, the Sn coating material with a smooth surface is because the soft Sn that becomes a frictional resistance at the time of inserting the terminal is continuously dug up and the dug up Sn adheres to the fitting portion. The friction coefficient of the surface is large, and the insertion force of the single terminal is large. As the terminal insertion force increases, the insertion force of a connector composed of a plurality of terminals also increases. Therefore, the burden on the assembly worker increases due to the multipolarization of the connector.
[0005]
In order to reduce the insertion force of the connector, it is necessary to reduce the contact force of the terminals or reduce the friction coefficient. However, it is not preferable to reduce the contact force because there is a high possibility that reliable electrical connection, which is the original performance of the terminal, becomes impossible due to stress relaxation of the material and fine sliding friction of the surface layer. Therefore, it is important to reduce the friction coefficient.
[0006]
Accordingly, an object of the present invention is to provide an Sn-coated member that can provide a reliable electrical connection and has a small friction coefficient, and a method for manufacturing the same, in view of the conventional problems.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that the surface of copper or a copper alloy contains 80% by weight or more of Sn and has an average width of 5 to 5%. 100 μm so Average height is 0.1 to 1.0 By forming the island-shaped convex portions of μm, it was found that a reliable electrical connection can be provided and a Sn covering member having a small friction coefficient can be provided, and the present invention has been completed.
[0008]
That is, the Sn covering member according to the present invention contains 80% by weight or more of Sn on the surface of copper or a copper alloy and has an average width of 5 to 5. 100 μm so Average height is 0.1 to 1.0 The island-shaped convex part of μm is formed. In this Sn covering member, the ratio of the area of the island-shaped convex portion and the area of the flat portion other than the island-shaped convex portion on the surface of copper or copper alloy (the area of the island-shaped convex portion / the area of the flat portion) is 0.1

Thru

2 Is preferred. Moreover, it is preferable that the Sn content layer is formed in the surface layer part of the flat part. In this case, it is more preferable that a Ni-containing layer is formed between the copper or copper alloy and the Sn-containing layer. Furthermore, the angle θ formed between the tangent line of the island-shaped convex portion on the intersection line between the exposed surface of the island-shaped convex portion and the flat portion other than the island-shaped convex portion on the surface of copper or copper alloy, and the surface of the flat portion, It is preferable that 0 ° <θ <90 °.
[0009]
Moreover, the manufacturing method of Sn covering member by this invention is the surface of copper or a copper alloy. 0.2 Thru 1.0 1 μm to 300 seconds at a temperature of 230 ° C. to 800 ° C. after coating with a μm layer containing 80% by weight or more of Sn Control the temperature and time of the melt treatment under the melt treatment conditions By performing a melting process Of copper or copper alloy On the surface , Contains 80% by weight or more of Sn And an average width of 5 to 100 μm and an average height of 0.1 to 1.0 μm A convex portion is formed. In this method of manufacturing a Sn-coated member, before coating with a layer containing Sn, the surface of copper or copper alloy is made of Sn, Cu, Ni, Fe, Zn, Co, Au, Ag, Pb and P. It is preferable to coat with a single layer or multiple layers of an underlayer containing at least one element and having a thickness of 0.05 to 3 μm.
[0010]
In addition, in the method for producing a Sn-coated member according to the present invention, the surface of copper or a copper alloy is coated with a layer containing Ni having a thickness of 0.05 to 3 μm, and a Cu layer having a thickness of 0.05 to 3 μm is coated thereon. Coated with a layer containing a 0.2 Thru 1.0 After coating with μm of a layer containing 80% by weight or more of Sn, at a temperature of 230 to 800 ° C. for 1 to 300 seconds Control the temperature and time of the melt treatment under the melt treatment conditions By performing dissolution treatment Of copper or copper alloy On the surface , Contains 80% by weight or more of Sn And an average width of 5 to 100 μm and an average height of 0.1 to 1.0 μm An island-shaped convex part is formed.
[0011]
In the manufacturing method of the Sn covering member, the ratio of the area of the island-shaped convex portion and the area of the flat portion other than the island-shaped convex portion on the surface of copper or copper alloy (the area of the island-shaped convex portion / the area of the flat portion) )But 0.1

Thru

2 Is preferred. Furthermore, the angle θ formed between the tangent line of the island-shaped convex portion on the intersection line between the exposed surface of the island-shaped convex portion and the flat portion other than the island-shaped convex portion on the surface of copper or copper alloy, and the surface of the flat portion, It is preferable that 0 ° <θ <90 °.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the embodiment of the method for producing a Sn-coated member according to the present invention, a material composed of copper or a copper alloy is formed by plating, vapor deposition, or the like as necessary, with a thickness of 0.05 to 3 μm of Sn, Cu, Ni, Fe, Cover with a single layer or multiple layers of an underlayer containing at least one element of Zn, Co, Au, Ag, Pb and P, and then cover with a Sn-containing layer having a thickness of 0.1 to 2 μm Then, the island-shaped convex part having a width of 5 to 300 μm and a height of 0.1 to 1.5 μm is formed on the surface by controlling the processing conditions and performing the melting process.
[0013]
In the present specification, the Sn-containing layer refers to a layer made of a Sn-containing material containing 0 to 20% by weight of one or more of Pb, Zn, Cu and Ag in addition to Sn. The reason why the Sn content is 80% by weight or more is that when the Sn content is less than 80% by weight, it is difficult to form island-shaped protrusions during the melting process.
[0014]
The formed island-shaped convex portions are mainly made of an Sn-containing material aggregated by a melting process. By controlling the height, width, and area of the island-shaped convex portions, the amount of digging and adhesion of the soft Sn-containing layer is reduced, and a small amount of Sn-containing material has low shear resistance. In order to exhibit a lubricating action, the coefficient of friction is reduced. The flat portions other than the island-shaped convex portions are Sn-containing layers having a thickness of 1 μm or less, Cu ₆ Sn ₅ , Cu ₃ Sn, Ni ₃ Sn ₄ , Ni ₃ It is an alloy layer such as Sn or a layer of a base metal. Therefore, when the Vickers hardness is measured at a test force of 0.098 N or less, the Vickers hardness of the island-shaped convex portions is a value of 5 to 200, and the Vickers hardness other than the island-shaped convex portions is the value of the island-shaped convex portions. Also gets higher.
[0015]
When using the Sn covering member having island-shaped protrusions according to the present invention, there is an effect of reducing the coefficient of friction even if it is used on one side of a contact such as a terminal or bus bar, but if used on both sides of contact, the friction force is reduced. The effect is further enhanced.
[0016]
The angle formed by the island-shaped convex portion 1 and the flat portion 2 shown in FIG. 1 (the tangent of the island-shaped convex portion 1 on the intersection of the exposed surface of the island-shaped convex portion 1 and the flat portion 2 and the surface of the flat portion 2. The angle θ is preferably 0 ° <θ <90 °. This is because in order to reduce the friction coefficient, it is necessary to reduce the resistance of digging, and the angle θ should be less than 90 °. However, since no island-shaped convex portion is formed at 0 °, 0 ° <θ <90 °.
[0017]
Moreover, it is preferable that the width | variety of an island-shaped convex part shall be 5-300 micrometers, and height shall be 0.1-1.5 micrometers. In the formation of island-shaped convex portions by melting treatment, it is difficult to control the width to less than 5 μm and the height to less than 0.1 μm, and if the width exceeds 300 μm or the height exceeds 1.5 μm, This is because the amount of digging at the time of insertion increases and the effect of reducing the frictional force decreases. Therefore, it is preferable to control the width of the island-shaped convex portion to 5 to 300 μm and the height to 0.05 to 1.5 μm, and to control the width to 5 to 100 μm and the height to 0.1 to 1.0 μm. Is more preferable. In the present specification, the direction of “width” refers to a direction perpendicular to the rolling direction of copper or copper alloy as a material (the direction of line AB in FIG. 2), and the direction of “height” is The normal direction of the rolling surface of the copper or copper alloy used as the material.
[0018]
Moreover, it is preferable to control the melting treatment conditions so that the ratio of the area of the island-shaped convex portions to the area of the flat portions (area of the island-shaped convex portions / area of the flat portions) is 0.05-4. If the area ratio is less than 0.05, the lubrication action of the Sn-containing material is reduced, and the effect of reducing the frictional force is reduced. If the area ratio is more than 4, the amount of digging of the soft Sn-containing layer is increased and the frictional force is reduced. This is because becomes smaller. Therefore, it is preferable to control the melt processing conditions so that the ratio of the area of the island-shaped convex portions and the area of the flat portions is 0.05 to 4, and the melt processing conditions are controlled to be 0.1 to 2. Is more preferable.
[0019]
Moreover, it is preferable that the thickness of the Sn-containing layer before the melting treatment is in the range of 0.1 to 2 μm. If the thickness is less than 0.1 μm, the amount of Sn-containing material is insufficient, and it is difficult to form island-shaped protrusions even if the melting process is performed. If the thickness exceeds 2 μm, the Sn-containing material melted during the melting process tends to aggregate coarsely. As a result, the island-shaped convex portion also becomes coarse, and the effect of reducing the frictional force becomes small. Therefore, the thickness of the Sn-containing layer before the melting treatment is preferably in the range of 0.1 to 2 μm, and more preferably in the range of 0.2 to 1.0 μm.
[0020]
In addition, a single layer containing at least one element selected from the group consisting of Sn, Cu, Ni, Fe, Zn, Co, Au, Ag, Pb and P having a thickness of 0.05 to 3 μm under the Sn-containing layer It is preferable to provide a multiple underlayer. The reason for this will be described below. Cu, Zn, etc. in the substrate easily interdiffuse with the Sn-containing material to form an alloy layer. By forming the Sn-containing material of the surface layer into an island shape, it is possible to delay the entire amount of the Sn-containing material from becoming an alloy layer than when the Sn-containing material is smooth. End up. When the Sn-containing material is alloyed, an oxide other than the Sn-containing material is formed on the outermost layer, and the removal of the oxide becomes difficult due to the absence of the soft Sn-containing layer. As a result, the performance as a terminal deteriorates. Therefore, when reliability such as heat resistance is insufficient with only the Sn-containing layer, it is preferable to provide the above-described underlayer in order to prevent the material component and the Sn-containing layer from alloying. Moreover, when a hard layer having a Vickers hardness of more than 100 such as Cu-Sn or Ni-Sn alloyed with a coating layer such as Ni or Ni-P or a surface Sn-containing material is introduced under the Sn-containing layer. This has the effect of further reducing the frictional force.
[0021]
For the formation of the underlayer and the Sn-containing layer, electroplating excellent in cost and thickness control is preferably used, but electroless plating, vapor deposition, or molten metal dipping treatment may be used. In addition, if the time until the melting treatment is made after coating with the Sn-containing layer, an oxide film on the surface grows, the flow of the molten Sn-containing material during the melting treatment becomes worse, and it is difficult to form island-shaped convex portions. Therefore, the time from the formation of the Sn-containing layer to the melting treatment is preferably as short as possible. It is preferable to melt the Sn-containing layer within 1 hour after the formation, but when managing indoors, there is no problem until about 3 days, and the island-shaped convex portions cannot be formed uniformly after 1 week. However, even in such a case, if an activation process such as pickling is performed immediately before the melting process, it is possible to form the island-shaped convex part again.
[0022]
The melting process can be performed by a burner furnace, an electric furnace, a hot air circulating furnace, a muffle furnace, an electric annealing apparatus, or the like. If the surface Sn-containing material can be melted by heat, for example, laser or infrared rays are used. May be.
[0023]
In order to form island-shaped convex portions, it is important to control the temperature and time of the melting process. The Sn-containing material melts when the surface temperature of the copper or copper alloy coated with the Sn-containing material exceeds the melting point (232 ° C. if the Sn-containing material is 100% Sn), and on the side in contact with the base coating layer or material A diffusion layer is formed. On the surface side, a smooth surface is maintained in the initial stage of melting, but when heat is applied beyond that, aggregation of the molten Sn-containing material starts to form dispersed island-shaped convex portions. When the amount of heat is further applied, the island-shaped convex portion becomes coarse or the diffusion layer grows up to the surface layer. In order to form the island-shaped convex portion according to the present invention, it is important to control the amount of heat. The method of controlling the amount of heat differs depending on the processing equipment, but when processing in a furnace such as a burner furnace or electric furnace, the furnace atmosphere temperature is controlled to 230 to 800 ° C, and the furnace holding (passing) time is controlled to 1 to 300 seconds. It is preferable to do this. When the conditions for smoothing the Sn-containing material are known, the island-shaped protrusions can be formed by raising the ambient temperature or extending the holding time.
[0024]
Moreover, in order to form an island-shaped convex part, it is also important to cool after a melting process. The cooling medium may be solid, liquid, or gas, but it must be capable of cooling to 50 ° C. or less within 1 minute.
[0025]
An island-shaped convex portion having a width of 5 to 300 μm, a height of 0.1 to 1.5 μm, and a ratio of the area of the island-shaped convex portion to the area of the flat portion formed by the above processing is 0.05 to 4. The Sn covering member has a small coefficient of friction on the surface layer, and can reduce the insertion force when used for terminals, bus bars, flat cables, and the like.
[0026]
【Example】
Hereinafter, examples of the Sn covering member and the manufacturing method thereof according to the present invention will be described in detail.
[0027]
[Example 1]
As a material, a copper alloy strip having a thickness of 0.25 mm and a Vickers hardness of 170 containing 1 wt% Ni, 0.9 wt% Sn, 0.05 wt% P in copper is prepared. After being activated by electrolytic degreasing and pickling, a coating layer made of a Sn-containing material containing 0 to 20% by weight of one or more of Pb, Zn, Cu and Ag in addition to Sn was formed thereon. . The coating layer was formed by plating using a sulfate bath using electroplating, which is advantageous in terms of cost and relatively easy to control the thickness.
[0028]
After electroplating, using a burner furnace, the furnace temperature is 600 ° C., the furnace passage time is 8 seconds, melting is performed in a reducing atmosphere, and then cooling is performed using water and a blower together, followed by Sn coating. A member was prepared.
[0029]
For the Sn-coated member produced in this example, the thickness of the coating layer, the average width and height of the island-shaped convex portions, the area ratio, and the Vickers hardness were measured.
[0030]
The thickness of the coating layer was measured using a fluorescent X-ray film thickness meter by separately preparing a sample that was not melted after plating under the same conditions as in this example. As a result, the thickness of the coating layer made of the Sn-containing material was 0.4 μm.
[0031]
The average width of the island-shaped convex portions was measured based on the result of observing Nomarski differential interference by enlarging the plating surface 200 times with a metal microscope. Do not measure the area of island-shaped protrusions Calculation Went by law. As a result, the average width of the island-shaped convex portions was 20 μm, and the area ratio (area of the island-shaped convex portions / area of the flat portion) was 0.12.
[0032]
The average height of the island-shaped convex portions was measured using a three-dimensional laser microscope. As a result, the average height of the island-shaped convex portions was 0.4 μm. Further, the angle θ formed by the island-shaped convex portion and the flat portion was also measured using a three-dimensional laser microscope, and it was confirmed that both were within 0 ° <θ <90 °.
[0033]
Vickers hardness was measured with a test force of 0.098N. The measurement position was confirmed with an attached monitor, and the island-shaped convex portion was measured at the center. As a result, the Vickers hardness of the island-shaped convex portion was 135, and the Vickers hardness of the portion other than the island-shaped convex portion was 170.
[0034]
Moreover, about the Sn coating | coated member produced in this Example, while measuring the friction coefficient and the contact resistance value after high temperature holding, the heat-resistant discoloration test was done.
[0035]
As shown in FIG. 2, the friction coefficient is the same test in which a test material (lower material) (width 50 mm × length 300 mm) 7 is fixed to a horizontal base 9 and a weight 8 having a mass of 15 N is pasted thereon. A frictional force is measured by placing a material (upper material) 6 and pulling it with a load cell 11 through a pulley 10 at a speed of 100 mm / min. Based on the frictional force, {friction coefficient = force applied in the horizontal direction / vertical direction The power of In order to eliminate the influence of burrs on the end face of the test material, the test material (upper material) 6 was given three indents of R = 1 mm. As a result, the friction coefficient was 0.20.
[0036]
The contact resistance value after holding at high temperature is that the test material is held at 160 ° C. for 120 hours in the air atmosphere, and then using an electric contact simulator and a micro ohm meter, the current is 10 mA, the maximum sliding contact load of the Au probe is 0.49 N Measured with As a result, the contact resistance value after holding at high temperature was 5 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ.
[0037]
The heat discoloration test was performed by visually observing the discoloration of the surface after holding the test material at 180 ° C. for 1 hour in an air atmosphere. As a result, it was observed that no discoloration occurred.
[0038]
[Example 2]
As the material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a base layer made of Ni was formed thereon, and Example 1 and A coating layer made of the same Sn-containing material was formed. These underlayers and coating layers were formed by electroplating in the same manner as in Example 1, with the underlayer Ni being plated using a nickel sulfamate bath and the surface Sn-containing material using a sulfate bath.
[0039]
After electroplating, using a burner furnace, the furnace temperature is 600 ° C., the furnace passage time is 8 seconds, and the melting treatment is performed in a reducing atmosphere. A member was prepared.
[0040]
For the Sn covering member produced in this example, the thickness of the base layer and the covering layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 1. . As a result, the thickness of the underlayer made of Ni was 0.5 μm, and the thickness of the coating layer made of the Sn-containing material was 0.4 μm. The average width of the island-shaped convex portions was 25 μm, and the area ratio (area of the island-shaped convex portions / area of the flat portion) was 0.15. Further, the average height of the island-shaped convex portions was 0.4 μm, and it was confirmed that the angle θ formed between the island-shaped convex portions and the flat portion was within 0 ° <θ <90 °. Furthermore, the Vickers hardness of the island-shaped convex portion was 125, and the Vickers hardness of the portion other than the island-shaped convex portion was 160.
[0041]
For the Sn-coated member produced in this example, the coefficient of friction and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was conducted. As a result, the coefficient of friction was 0.22, and the contact resistance value after holding at high temperature was 5 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0042]
[Example 3]
As a material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a base layer made of Ni was formed thereon, and a lower layer made of Cu was formed thereon. A base layer was formed, and a coating layer made of the same Sn-containing material as in Example 1 was further formed thereon. These underlayers and coating layers were electroplated in the same manner as in Example 1. The underlayer Ni was plated with a nickel sulfamate bath, the Cu was a copper sulfate bath, and the surface Sn-containing material was plated with a sulfate bath. Was formed.
After electroplating, using a burner furnace, the furnace temperature is 600 ° C., the furnace passage time is 8 seconds, and the melting treatment is performed in a reducing atmosphere. A member was prepared.
[0043]
For the Sn covering member produced in this example, the thickness of the base layer and the covering layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 1. . The thickness of the underlayer was measured for Ni using a fluorescent X-ray film thickness meter in the same manner as in Example 2, and for Cu using an electrolytic film thickness meter. As a result, the thickness of the base layer made of Ni was 0.3 μm, the thickness of the base layer made of Cu was 0.2 μm, and the thickness of the coating layer made of the Sn-containing material was 0.5 μm. The average width of the island-shaped convex portions was 50 μm, and the area ratio (area of the island-shaped convex portions / area of the flat portion) was 0.30. Further, the average height of the island-shaped convex portions was 0.3 μm, and it was confirmed that the angle θ formed between the island-shaped convex portions and the flat portion was within 0 ° <θ <90 °. Furthermore, the Vickers hardness of the island-shaped convex portion was 125, and the Vickers hardness of the portion other than the island-shaped convex portion was 165.
[0044]
For the Sn-coated member produced in this example, the coefficient of friction and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was conducted. As a result, the coefficient of friction was 0.23, and the contact resistance value after holding at high temperature was 1 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0045]
[Example 4]
As the material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a coating layer made of the same Sn-containing material as in Example 1 was formed thereon. The coating layer was formed by plating using a sulfate bath using electroplating in the same manner as in Example 1 except that the plating time was different from that in Example 1.
[0046]
After electroplating, using a burner furnace, the furnace temperature is 600 ° C., the furnace passage time is 8 seconds, and the melting treatment is performed in a reducing atmosphere. A member was prepared.
[0047]
For the Sn-coated member produced in this example, the thickness of the coating layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 1. As a result, the thickness of the coating layer made of the Sn-containing material was 0.7 μm. The average width of the island-shaped convex portions was 25 μm, and the area ratio (area of the island-shaped convex portions / area of the flat portion) was 0.12. Further, the average height of the island-shaped convex portions was 0.2 μm, and it was confirmed that the angle θ formed between the island-shaped convex portions and the flat portion was within 0 ° <θ <90 °. Furthermore, the Vickers hardness of the island-shaped convex portion was 130, and the Vickers hardness of the portion other than the island-shaped convex portion was 175.
[0048]
For the Sn-coated member produced in this example, the coefficient of friction and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was conducted. As a result, the friction coefficient was 0.22, and the contact resistance value after holding at high temperature was 4 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0049]
[Example 5]
As the material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a coating layer made of the same Sn-containing material as in Example 1 was formed thereon. The coating layer was formed by plating using a sulfate bath using electroplating in the same manner as in Example 1 except that the plating time was different from that in Example 1.
[0050]
After electroplating, use a burner furnace to perform melting treatment in a reducing atmosphere at a furnace temperature of 600 ° C. and a furnace passage time of 9 seconds, and then cool with water and a blower in combination. A member was prepared.
[0051]
For the Sn-coated member produced in this example, the thickness of the coating layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 1. As a result, the thickness of the coating layer made of the Sn-containing material was 0.7 μm. The average width of the island-shaped convex portions was 50 μm, and the area ratio (area of the island-shaped convex portions / area of the flat portion) was 0.18. Further, the average height of the island-shaped convex portions was 0.4 μm, and it was confirmed that the angle θ formed between the island-shaped convex portions and the flat portion was within 0 ° <θ <90 °. Furthermore, the Vickers hardness of the island-shaped convex portion was 110, and the Vickers hardness of the portion other than the island-shaped convex portion was 175.
[0052]
For the Sn-coated member produced in this example, the coefficient of friction and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was conducted. As a result, the friction coefficient was 0.24, and the contact resistance value after holding at high temperature was 4 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0053]
[Example 6]
As a material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a base layer made of Ni was formed thereon, and a lower layer made of Cu was formed thereon. A base layer was formed, and a coating layer made of the same Sn-containing material as in Example 1 was further formed thereon. These underlayers and coating layers were electroplated in the same manner as in Example 3 except that the plating time was different from that in Example 3. The underlying Ni was a nickel sulfamate bath, Cu was a copper sulfate bath, and the surface layer. The Sn-containing material was formed by plating using a sulfate bath.
[0054]
After the electroplating, using a burner furnace, the furnace temperature is 630 ° C., the furnace passage time is 8 seconds, the melting treatment is performed in a reducing atmosphere, and then cooling is performed using water and a blower together, and Sn coating is performed. A member was prepared.
[0055]
For the Sn covering member produced in this example, the thickness of the underlayer and the covering layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 3. . As a result, the thickness of the base layer made of Ni was 0.5 μm, the thickness of the base layer made of Cu was 0.4 μm, and the thickness of the coating layer made of the Sn-containing material was 1.0 μm. The average width of the island-shaped convex portions was 40 μm, and the area ratio (area of the island-shaped convex portions / area of the flat portion) was 0.28. In addition, the average height of the island-shaped convex portions was 0.7 μm, and it was confirmed that the angle θ formed between the island-shaped convex portions and the flat portion was within 0 ° <θ <90 °. Furthermore, the Vickers hardness of the island-shaped convex portion was 105, and the Vickers hardness of the portion other than the island-shaped convex portion was 155.
[0056]
For the Sn-coated member produced in this example, the coefficient of friction and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was conducted. As a result, the friction coefficient was 0.27, and the contact resistance value after holding at high temperature was 1 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0057]
[Example 7]
As the material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a coating layer made of the same Sn-containing material as in Example 1 was formed thereon. The coating layer was formed by plating using a sulfate bath using electroplating in the same manner as in Example 1 except that the plating time was different from that in Example 1.
[0058]
After the electroplating, using a burner furnace, the furnace temperature is 630 ° C., the furnace passage time is 8 seconds, the melting treatment is performed in a reducing atmosphere, and then cooling is performed using water and a blower together, and Sn coating is performed. A member was prepared.
[0059]
For the Sn-coated member produced in this example, the thickness of the coating layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 1. As a result, the thickness of the coating layer made of the Sn-containing material was 1.2 μm. The average width of the island-shaped convex portions was 60 μm, and the area ratio (area of the island-shaped convex portions / area of the flat portion) was 0.49. Further, the average height of the island-shaped convex portions was 0.6 μm, and it was confirmed that the angle θ formed between the island-shaped convex portions and the flat portion was within 0 ° <θ <90 °. Furthermore, the Vickers hardness of the island-shaped convex portion was 105, and the Vickers hardness of the portion other than the island-shaped island-shaped convex portion was 160.
[0060]
For the Sn-coated member produced in this example, the coefficient of friction and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was conducted. As a result, the friction coefficient was 0.28, and the contact resistance value after holding at high temperature was 3 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0061]
[Comparative Example 1]
As the material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a coating layer made of the same Sn-containing material as in Example 1 was formed thereon. The coating layer was formed by plating using a sulfate bath using electroplating in the same manner as in Example 1 except that the plating time was different from that in Example 1.
[0062]
After performing the electroplating, using a burner furnace, the melting process is performed in a reducing atmosphere that gives an amount of heat more than in Example 1, that is, the furnace temperature is 600 ° C., the furnace passage time is 10 seconds, and the reducing atmosphere is used. Then, it cooled by using water and a blower together, and produced the Sn covering member.
[0063]
For the Sn-coated member produced in this comparative example, the thickness of the coating layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 1. As a result, the thickness of the coating layer made of the Sn-containing material was 0.1 μm. In addition, all the Sn-containing material diffused after the melting treatment, and no island-shaped convex portions were formed. Further, the Vickers hardness of the portion other than the island-shaped convex portion was 190.
[0064]
Further, for the Sn-coated member produced in this comparative example, the friction coefficient and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was performed. As a result, the friction coefficient was 0.23, and the contact resistance value after holding at high temperature was 12 mΩ. The contact resistance value before the heat test (initial state) was 2 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0065]
[Comparative Example 2]
As the material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a coating layer made of the same Sn-containing material as in Example 1 was formed thereon. The coating layer was formed by plating using a sulfate bath using electroplating in the same manner as in Example 1 except that the plating time was different from that in Example 1.
[0066]
After electroplating, using a burner furnace, the melting treatment conditions are such that the plated surface is entirely covered with a smooth Sn-containing layer, that is, the furnace temperature is 600 ° C., the furnace passage time is 10 seconds, and the melting treatment is performed in a reducing atmosphere. After that, cooling was performed using water and a blower together to produce a Sn-coated member.
[0067]
For the Sn-coated member produced in this comparative example, the thickness of the coating layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 1. As a result, the thickness of the coating layer made of the Sn-containing material was 0.7 μm. Moreover, the plated surface was entirely covered with a smooth Sn-containing layer after the melting treatment, and no island-shaped convex portions were formed. Further, the Vickers hardness of the portion covered with the Sn-containing layer was 100.
[0068]
Further, for the Sn-coated member produced in this comparative example, the friction coefficient and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was performed. As a result, the coefficient of friction was 0.32, and the contact resistance value after holding at high temperature was 3 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0069]
[Comparative Example 3]
As the material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a coating layer made of the same Sn-containing material as in Example 1 was formed thereon. The coating layer was formed by plating using a sulfate bath using electroplating in the same manner as in Example 1 except that the plating time was different from that in Example 1.
[0070]
After electroplating, using a burner furnace, melt processing conditions that give more heat than in Examples 4 and 5, ie, furnace temperature 600 ° C., furnace passage time 12 seconds, melting treatment in a reducing atmosphere After that, cooling was performed using water and a blower together to produce a Sn-coated member.
[0071]
For the Sn-coated member produced in this comparative example, the thickness of the coating layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 1. As a result, the thickness of the coating layer made of the Sn-containing material was 0.7 μm. The average width of the island-shaped convex portions was 400 μm, and the area ratio (area of the island-shaped convex portions / area of the flat portion) was 5.67. Further, the average height of the island-shaped convex portions was 1.6 μm, and it was confirmed that the angle θ formed between the island-shaped convex portions and the flat portion was within 0 ° <θ <90 °. Furthermore, the Vickers hardness of the island-shaped convex portion was 75, and the Vickers hardness of the portion other than the island-shaped convex portion was 155.
[0072]
Further, for the Sn-coated member produced in this comparative example, the friction coefficient and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was performed. As a result, the coefficient of friction was 0.31, and the contact resistance value after holding at high temperature was 5 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Moreover, it was observed in the heat-resistant discoloration test that it had discolored.
[0073]
[Comparative Example 4]
As a material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a base layer made of Ni was formed thereon, and a lower layer made of Cu was formed thereon. A base layer was formed, and a coating layer made of the same Sn-containing material as in Example 1 was further formed thereon. These underlayers and coating layers were electroplated in the same manner as in Example 3 except that the plating time was different from that in Example 3. The underlying Ni was a nickel sulfamate bath, Cu was a copper sulfate bath, and the surface layer. The Sn-containing material was formed by plating using a sulfate bath.
[0074]
After electroplating, using a burner furnace, the melting process conditions are such that the plated surface is entirely covered with a smooth Sn-containing layer, that is, the furnace temperature is 630 ° C., the furnace passage time is 6 seconds, and the melting process is performed in a reducing atmosphere. After that, cooling was performed using water and a blower together to produce a Sn-coated member.
[0075]
For the Sn covering member produced in this comparative example, the thickness of the underlayer and the covering layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 3. . As a result, the thickness of the base layer made of Ni was 0.5 μm, the thickness of the base layer made of Cu was 0.4 μm, and the thickness of the coating layer made of the Sn-containing material was 1.0 μm. Moreover, the plated surface was entirely covered with a smooth Sn-containing layer after the melting treatment, and no island-shaped convex portions were formed. Furthermore, the Vickers hardness of the portion covered with the Sn-containing layer was 95.
[0076]
For the Sn-coated member produced in this comparative example, the friction coefficient and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was conducted. As a result, the coefficient of friction was 0.40, and the contact resistance value after holding at high temperature was 1 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0077]
[Comparative Example 5]
As the material, the same copper alloy strip as in Example 1 was prepared, and after the surface of the copper alloy was activated by electrolytic degreasing and pickling, a coating layer made of the same Sn-containing material as in Example 1 was formed thereon. The coating layer was formed by plating using a sulfate bath using electroplating in the same manner as in Example 1 except that the plating time was different from that in Example 1.
[0078]
After electroplating, using a burner furnace, the melting process conditions are such that the plated surface is entirely covered with a smooth Sn-containing layer, that is, the furnace temperature is 630 ° C., the furnace passage time is 6 seconds, and the melting process is performed in a reducing atmosphere. After that, cooling was performed using water and a blower together to produce a Sn-coated member.
[0079]
For the Sn-coated member produced in this comparative example, the thickness of the coating layer, the average width and height of the island-shaped protrusions, the area ratio, and the Vickers hardness were measured in the same manner as in Example 1. As a result, the thickness of the coating layer made of the Sn-containing material was 1.2 μm. Moreover, the plated surface was entirely covered with a smooth Sn-containing layer after the melting treatment, and no island-shaped convex portions were formed. Furthermore, the Vickers hardness of the part covered with the Sn-containing layer was 75.
[0080]
Further, for the Sn-coated member produced in this comparative example, the friction coefficient and the contact resistance value after holding at high temperature were measured by the same method as in Example 1, and a heat discoloration test was performed. As a result, the friction coefficient was 0.46, and the contact resistance value after holding at high temperature was 2 mΩ. In addition, the contact resistance value before the heat test (initial state) was 1 mΩ. Further, it was observed that no discoloration occurred in the heat discoloration test.
[0081]
As described above, each of the Sn-coated members of Examples 1 to 7 has a small coefficient of friction, a contact resistance after holding at high temperature of less than 10 mΩ, and the surface after holding at high temperature is not discolored. Therefore, the Sn covering member according to the present invention is suitable for use in terminals for electrical connection, bus bars, flat cables and the like, and in particular, multipolar connector terminals that require a reduction in insertion force, industrial machinery, consumer equipment, etc. It is extremely suitable for use in connector terminals for connection.
[0082]
Further, the Sn-coated members of Example 3 and Example 6 in which a copper or copper alloy material is coated with an underlayer of Ni and Cu have a small increase in contact resistance after a heat resistance test, and particularly an automobile that requires heat resistance. It is extremely useful for a connector used in an engine room.
[0083]
In contrast, the Sn-coated member of Comparative Example 1 in which all of the Sn-containing material coated by the melting treatment was diffused by Cu—Sn and no island-shaped convex portions were formed on the surface was considerably inferior in terms of contact resistance. .
[0084]
When compared with the same plating configuration, the Sn-coated member of Comparative Example 2 having a Sn-containing layer thickness of 0.7 μm and a smooth surface, and Sn of Comparative Example 3 in which the island-shaped protrusions are coarsened by overmelting treatment The covering member has a larger coefficient of friction than the Sn covering members of Example 4 and Example 5. Furthermore, the Sn covering member of Comparative Example 3 is inferior in terms of surface discoloration. Similarly, the Sn coated members of Comparative Examples 4 and 5 having smooth surfaces have a friction coefficient larger than that of the Sn coated members of Examples 6 and 7 having the same plating configuration.
[0085]
In addition, the result about Examples 1-7 and Comparative Examples 1-5 is put together in Table 1 and Table 2, and is shown.
[0086]
[Table 1]

[0087]
[Table 2]

[0088]
In addition, although the copper alloy was used as a raw material in the Example, even if it uses copper, the effect similar to the effect mentioned above can be acquired.
[0089]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a Sn-coated member having a low friction coefficient and excellent contact resistance and discoloration resistance after holding at a high temperature. In addition, it is possible to provide an excellent Sn covering member as a material for electrical / electronic parts that requires a reduction in insertion force and reliability of electrical connection during long-term connection, such as connector terminals for industrial machines and consumer devices.
[Brief description of the drawings]
1A and 1B are schematic views showing island-shaped convex portions of an Sn covering member manufactured in an example, FIG. 1A is a plan view, and FIG. 1B is a line AB in FIG. Sectional drawing.
FIG. 2 is a diagram showing a method for measuring a friction coefficient in Examples and Comparative Examples.
[Explanation of symbols]
1 Island-shaped convex part
2 flat part
6 Test material (upper material)
7 Test material (lower material)
8 weights (15N)
9 Horizontal stand
10 pulley
11 Load cell

Claims

On the surface of copper or a copper alloy, the height of the average width of the content to and average of 80% or more by weight of Sn is 5 to 100μm is formed island-like protrusions of 0.1 to 1.0 .mu.m, like the island The ratio of the area of the convex portion to the area other than the island-shaped convex portion on the surface of copper or copper alloy (area of the island-shaped convex portion / area of the flat portion) is 0.1 to 2, and the island shape Vickers hardness of the convex portion, characterized in that 155 to 175 der Rukoto Vickers hardness of 105 to 135 and the flat portion, Sn covering member.

After the surface of copper or copper alloy is coated with a layer containing 80 wt% or more of Sn having a thickness of 0.2 to 1.0 μm, it is melted at a temperature of 230 to 800 ° C. for 1 to 300 seconds. By controlling the temperature and time of the treatment and performing the melting treatment, the surface of the copper or copper alloy contains 80% by weight or more of Sn, the average width is 5 to 100 μm, and the average height is 0.1. To 1.0 μm island-shaped protrusions, and the ratio of the area of the island-shaped protrusions to the area other than the island-shaped protrusions on the surface of copper or copper alloy (area of island-shaped protrusions / area of the flat portion) is 0.1 to 2, the Vickers hardness of the island-shaped protrusions, characterized in that 155 to 175 der Rukoto Vickers hardness of 105 to 135 and the flat portion, of the Sn coating member Production method.

The method for producing a Sn-coated member according to claim 2, wherein the melting treatment is performed at a temperature of 600 to 630 ° C for 8 to 9 seconds.