JP2020002429A - Conductive member for connector terminal and connector terminal - Google Patents
Conductive member for connector terminal and connector terminal Download PDFInfo
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本発明は、コネクタ用導電部材及び該導電部材により形成したコネクタ端子に関する。 The present invention relates to a conductive member for a connector and a connector terminal formed by the conductive member.
最近、表面にＡｇめっきが施された銅合金条材が耐摩耗性及び導電性が要求される電気自動車の充電用プラグ部、各種摺動部、モーター部、充電部などのコネクタ部材として使用されている。
この電気自動車の充電用プラグ部のコネクタ部品などにおいて、高電流・高電圧環境下での使用に加えて数万回の抜き差しに耐えうる耐摩耗性が求められるようになってきている。この課題に対して、特許文献１により、表面に錫めっきを施した銅合金材料上に電解ニッケルめっきを施した後、さらに電解銀めっきを施しためっき積層体が提案されている。
Recently, copper alloy strips whose surfaces have been plated with Ag are used as connector members for charging plugs, various sliding parts, motors, charging parts, etc. of electric vehicles requiring abrasion resistance and conductivity. ing.
The connector parts of the charging plug portion of the electric vehicle and the like are required to have wear resistance that can withstand tens of thousands of insertions and removals in addition to use under high current and high voltage environments. To cope with this problem, Patent Literature 1 proposes a plating laminate in which electrolytic nickel plating is performed on a copper alloy material whose surface is plated with tin, and then electrolytic silver plating is performed.
しかしながら、抜き差しの繰り返しによりめっきの摩耗が進行し、母材に達することで急激な電気抵抗の増大を招くおそれがあった。また、折り曲げなどにより形成しためっき皮膜が剥離する問題もあった。
また、特許文献２では、Ｃｕ系基材の上にＣｕ−Ｓｎ金属間化合物層、Ｓｎ系表面層を順に備え、Ｓｎ系表面層の上にＮｉめっき、硬質Ａｇめっきを施したコネクタ用導電部材が提案され、コネクタとして長時間実装された後もある程度の高い表面硬度を維持することにより耐摩耗性が向上したが、電気自動車の高性能化等に伴い、使用されるコネクタ数およびその端子数も増加し、より細かい曲げ加工が必要となってきていることから、耐摩耗性のさらなる改良と共に曲げ加工性についてもさらなる改良が望まれていた。
However, there is a possibility that abrasion of the plating progresses due to repeated insertion and removal and reaches the base metal, causing a sudden increase in electric resistance. There is also a problem that a plating film formed by bending or the like peels off.
Further, in Patent Document 2, a conductive member for a connector in which a Cu-Sn intermetallic compound layer and a Sn-based surface layer are sequentially provided on a Cu-based substrate, and Ni plating and hard Ag plating are applied on the Sn-based surface layer Although the wear resistance has been improved by maintaining a certain high surface hardness even after being mounted as a connector for a long time, the number of connectors and the number of terminals used with the improvement in the performance of electric vehicles, etc. And the need for finer bending work has increased, and further improvement in bending workability as well as wear resistance has been desired.
本発明では、前記事情に鑑みてなされたもので、耐摩耗性をさらに向上させ、電気抵抗の増大を抑制するとともに、曲げ加工等の際の剥離の発生を確実に防止することを目的とする。 The present invention has been made in view of the above circumstances, and aims to further improve wear resistance, suppress an increase in electric resistance, and reliably prevent the occurrence of peeling during bending or the like. .
本発明のコネクタ端子用導電部材は、Ｃｕ又はＣｕ合金からなる基材の上に、Ｃｕ及びＳｎの金属間化合物からなるＣｕ−Ｓｎ金属間化合物層が形成され、該Ｃｕ−Ｓｎ金属間化合物層の上にＳｎ又はＳｎ合金からなるＳｎ層が形成されており、前記Ｓｎ層の表面において、端子に成形したときに端子同士が嵌合により接触状態となる予定の嵌合予定部位に、ストライプ状に部分皮膜が形成されており、該部分皮膜は、前記Ｓｎ層の上に形成されたＮｉ又はＮｉ合金からなるＮｉ層と、該Ｎｉ層の上に形成されたＡｇ又はＡｇ合金からなるＡｇ層とを有し、
前記Ｓｎ層における前記Ｎｉ層との界面部に、ＳｎにＮｉが固溶してなるＳｎ−Ｎｉ固溶体及び／又はＳｎとＮｉとの金属間化合物を含有するＳｎ−Ｎｉ層が形成され、
前記Ｎｉ層における前記基材の圧延面に対する法線方向から視た平均結晶粒径が１０ｎｍ以上５００ｎｍ以下であり、該平均結晶粒径の変動係数が１以下である。
なお、前記Ｓｎ−Ｎｉ層は、Ｓｎ層にＮｉが拡散することによって形成されるものであるが、局所的にＳｎが合金化せずそのまま存在している場合もある。平均結晶粒径の変動係数とは、平均結晶粒径の標準偏差を平均結晶粒径で割った値である。
In the conductive member for a connector terminal of the present invention, a Cu-Sn intermetallic compound layer made of an intermetallic compound of Cu and Sn is formed on a base material made of Cu or a Cu alloy, and the Cu-Sn intermetallic compound layer is formed. A Sn layer made of Sn or a Sn alloy is formed on the surface of the Sn layer, and a stripe-shaped portion is formed on a surface of the Sn layer at a portion where the terminals are to be in a contact state by fitting when the terminals are formed. A partial film is formed on the Sn layer, the Ni layer formed on the Sn layer is made of Ni or Ni alloy, and the Ag layer formed on the Ni layer is made of Ag or Ag alloy And having
An Sn—Ni layer containing a Sn—Ni solid solution in which Ni is dissolved in Sn and / or an intermetallic compound of Sn and Ni is formed at an interface between the Sn layer and the Ni layer,
The average crystal grain size of the Ni layer as viewed from the normal to the rolled surface of the substrate is 10 nm or more and 500 nm or less, and the coefficient of variation of the average crystal grain size is 1 or less.
The Sn—Ni layer is formed by diffusing Ni into the Sn layer. However, there is a case where Sn is not alloyed locally but remains as it is. The variation coefficient of the average crystal grain size is a value obtained by dividing the standard deviation of the average crystal grain size by the average crystal grain size.
このコネクタ端子用導電部材は、端子に成形したときに端子同士が嵌合により接触状態となる予定の嵌合予定部位に、表面にＡｇ層を有する部分皮膜が形成されているので、耐摩耗性に優れている。この部分皮膜は嵌合予定部位にストライプ状に形成しているので、高価なＡｇ層の使用が局部に制限され、コスト増を抑制することができる。また、このストライプ状の部分皮膜において、Ｓｎ層とＮｉ層との間にＳｎ−Ｎｉ固溶体及び／又はＳｎ−Ｎｉ金属間化合物からなるＳｎ−Ｎｉ層が介在しているので、Ｎｉ層とＳｎ層との結合状態がより強固かつ安定的になり、コネクタとして挿抜を繰り返しても摩耗しにくく、抵抗値が安定して維持される。また、皮膜の密着性が高まるので、折り曲げ加工等によっても皮膜の剥離が生じにくい。このため、コネクタ用導電部材として高い信頼性を維持することができる。
この場合、Ｎｉ層の平均結晶粒径が１０ｎｍ未満では、微細な結晶により耐摩耗性は向上するも、硬くなり過ぎて曲げ加工時に割れが生じ易い。Ｎｉ層の平均結晶粒径が５００ｎｍを超える粗大な結晶粒となると、耐摩耗性が低下する。また、平均結晶粒径の変動係数が１を超えると、結晶粒径のばらつきが大きくなり、実用上好ましいレベルの耐摩耗性を安定して得ることができない。
The conductive member for a connector terminal has a partial coating having an Ag layer on its surface at a portion where the terminal is to be brought into contact by fitting when the terminal is molded, so that the abrasion resistance is high. Is excellent. Since the partial film is formed in a stripe shape at the portion to be fitted, the use of the expensive Ag layer is restricted to a local area, and an increase in cost can be suppressed. In this striped partial film, since the Sn—Ni layer made of a Sn—Ni solid solution and / or Sn—Ni intermetallic compound is interposed between the Sn layer and the Ni layer, the Ni layer and the Sn layer And the connector is more firmly and stably connected, is less likely to be worn even after repeated insertion and removal as a connector, and maintains a stable resistance value. Further, since the adhesion of the film is enhanced, the film is less likely to be peeled even by bending or the like. Therefore, high reliability can be maintained as the conductive member for the connector.
In this case, if the average crystal grain size of the Ni layer is less than 10 nm, the wear resistance is improved by fine crystals, but it is too hard and cracks are likely to occur during bending. When the average crystal grain size of the Ni layer becomes coarse crystal grains exceeding 500 nm, the wear resistance is reduced. On the other hand, when the variation coefficient of the average crystal grain size exceeds 1, the variation in the crystal grain size becomes large, and a practically preferable level of wear resistance cannot be stably obtained.
本発明のコネクタ端子用導電部材の好ましい実施態様として、前記Ｓｎ−Ｎｉ層の含まれるＳｎ−Ｎｉ固溶体及び／又はＳｎ−Ｎｉ金属間化合物の平均結晶粒径が０．２μｍ以上５μｍ以下であることが好ましい。
Ｓｎ−Ｎｉ固溶体及び／又はＳｎ−Ｎｉ金属間化合物の平均結晶粒径をこの範囲にすることで、Ｓｎ層とＮｉ層の密着性が向上する。平均結晶粒径がこの範囲を外れたものは、密着性の向上効果が十分には得られなくなる。
As a preferred embodiment of the conductive member for a connector terminal of the present invention, the average crystal grain size of the Sn-Ni solid solution and / or the Sn-Ni intermetallic compound contained in the Sn-Ni layer is 0.2 μm or more and 5 μm or less. Is preferred.
By setting the average crystal grain size of the Sn-Ni solid solution and / or the Sn-Ni intermetallic compound in this range, the adhesion between the Sn layer and the Ni layer is improved. If the average crystal grain size is out of this range, the effect of improving the adhesion cannot be sufficiently obtained.
本発明のコネクタ端子用導電部材の好ましい実施態様として、前記Ｓｎ−Ｎｉ層におけるＮｉの含有量は５ａｔ％以上であるのが好ましい
Ｓｎ−Ｎｉ層中にＮｉ含有量を５ａｔ％以上とすることで、安定したＳｎ−Ｎｉ金属間化合物層が形成され、Ｓｎ層とＮｉ層の密着性が向上する。その含有量が５ａｔ％未満であると、Ｓｎ含有量が多過ぎるため、柔らかくなり過ぎて耐摩耗性低下のおそれがある。Ｎｉ含有量の上限は６７ａｔ％が好ましい。
As a preferred embodiment of the conductive member for connector terminals of the present invention, the content of Ni in the Sn—Ni layer is preferably 5 at% or more. By setting the Ni content in the Sn—Ni layer to 5 at% or more. As a result, a stable Sn-Ni intermetallic compound layer is formed, and the adhesion between the Sn layer and the Ni layer is improved. If the content is less than 5 at%, the Sn content is too large, so that it becomes too soft and may cause a decrease in wear resistance. The upper limit of the Ni content is preferably 67 at%.
Ｓｎ−Ｎｉ層におけるＳｎ−Ｎｉ固溶体及び／又はＳｎ−Ｎｉ金属間化合物の粒子が上記のような範囲で存在することにより、Ｓｎ層とＮｉ層の密着性が、界面全体でより安定的に強くなり、曲げ加工時の剥離発生のおそれが低くなる。 When the Sn—Ni solid solution and / or Sn—Ni intermetallic compound particles in the Sn—Ni layer are present in the above-described range, the adhesion between the Sn layer and the Ni layer is more stably enhanced over the entire interface. And the risk of peeling during bending is reduced.
本発明のコネクタ端子用導電部材の好ましい実施態様として、前記Ｎｉ層における前記基材の圧延面の法線方向から視た平均結晶粒径をｄＮＤとし、前記基材の圧延幅方向に対して垂直な面での平均結晶粒径をｄＴＤとすると、その粒径比ｄＴＤ／ｄＮＤが１以上１０以下であるとよい。
粒径比ｄＴＤ／ｄＮＤの比がこの範囲内であると、より耐摩耗性が良好になる。ｄＴＤ／ｄＮＤが１未満では、粒径が微細になることで、耐摩耗性は向上するが、細かくなり過ぎて、曲げた際に割れが生じ易くなる。ｄＴＤ／ｄＮＤが１０を超えると、ニッケル層の表面が粗くなり過ぎ、その凹凸の凸部が先行して摩耗することで摩耗粉が発生し、その摩耗粉の酸化による抵抗値の増大によって接続信頼性が低下するおそれがある。
As a preferred embodiment of the conductive member for connector terminals of the present invention, the average crystal grain size as viewed from the normal direction of the rolled surface of the base material in the Ni layer is d ND , with respect to the rolling width direction of the base material. Assuming that the average crystal grain size in a vertical plane is d TD , the grain size ratio d TD / d ND is preferably 1 or more and 10 or less.
When the ratio of the particle size ratio d TD / d ND is within this range, the abrasion resistance becomes better. When d TD / d ND is less than 1, the wear resistance is improved due to the fine particle diameter, but the particle diameter is too fine and cracks are likely to occur when bent. If d TD / d ND exceeds 10, the surface of the nickel layer becomes too rough, and the projections of the irregularities are worn first, thereby generating wear powder. Connection reliability may be reduced.
本発明のコネクタ端子用導電部材の好ましい実施態様として、前記Ｎｉ層において前記Ａｇ層と接する面の算術平均面高さＳａが０．５μｍ以下であるとよい。ここで、算術平均面高さＳａとは、ＩＳＯ２５１７８−２で定義されているａｒｉｔｈｍｅｔｉｃａｌ ｍｅａｎ ｈｅｉｇｈｔのことをいう。
Ｎｉ層におけるＡｇ層と接する面のＳａが０．５μｍ以下であると、耐摩耗性がさらに良好になる。０．５μｍを超えると、その凹凸の凸部が先行して摩耗することで摩耗粉が発生し、その摩耗粉の酸化による抵抗値の増大によって接続信頼性が低下するおそれがある。
As a preferred embodiment of the conductive member for connector terminals of the present invention, the arithmetic mean surface height Sa of the surface of the Ni layer in contact with the Ag layer is preferably 0.5 μm or less. Here, the arithmetic mean surface height Sa refers to the arithmetic mean height defined in ISO25178-2.
When the surface of the Ni layer in contact with the Ag layer has a Sa of 0.5 μm or less, the wear resistance is further improved. If it exceeds 0.5 μm, the projections of the unevenness will wear first, and wear powder will be generated, and the connection reliability may decrease due to an increase in resistance value due to oxidation of the wear powder.
本発明のコネクタ端子用導電部材は、前記基材は帯板状に形成されているとよい。帯板とすることにより、その長さ方向に沿って連続的に端子を製造することができる。
本発明のコネクタ端子は、前記コネクタ端子用導電部材からなり、相手端子に嵌合状態に接触する嵌合部を有し、該嵌合部の表面に前記部分皮膜が形成されている。
In the conductive member for a connector terminal of the present invention, the base material may be formed in a strip shape. By using the strip, the terminal can be manufactured continuously along the length direction.
The connector terminal of the present invention is formed of the conductive member for a connector terminal, has a fitting portion that comes into contact with a mating terminal in a fitted state, and the partial film is formed on a surface of the fitting portion.
本発明によれば、耐摩耗性が向上し、電気抵抗の増大を抑制するとともに、曲げ加工等の際の剥離の発生を確実に防止して、高い信頼性を維持することができる。 ADVANTAGE OF THE INVENTION According to this invention, while abrasion resistance improves, it suppresses the increase of an electrical resistance, generation | occurrence | production of peeling at the time of a bending process etc. is reliably prevented, and high reliability can be maintained.
以下、本発明のコネクタ端子用導電部材の実施形態を詳細に説明する。
コネクタ端子用導電部材１，１１は、Ｃｕ又はＣｕ合金からなる基材２の表面に、Ｃｕ及びＳｎの金属間化合物からなるＣｕ−Ｓｎ金属間化合物層３が形成され、Ｃｕ−Ｓｎ金属間化合物層３の上にＳｎ又はＳｎ合金からなるＳｎ層４が形成されており、そのＳｎ層４の表面の一部に部分皮膜５が形成されている。
具体的には、基材２は帯板状に形成された条材であり、Ｃｕ−Ｓｎ金属間化合物層３及びＳｎ層４が形成されためっき付条材６の表面に、図２及び図３に示すように、その長さ方向に沿ってストライプ状に部分皮膜５が形成されている。なお、図２は雄端子として用いられるコネクタ端子用導電部材１、図３は雌端子として用いられるコネクタ端子用導電部材１１を示している。
そして、このコネクタ端子用導電部材１，１１をプレス成形することにより、複数の端子が帯板の長さ方向に並んで連続的に成形される。
Hereinafter, an embodiment of a conductive member for connector terminals of the present invention will be described in detail.
In the connector terminal conductive members 1 and 11, a Cu-Sn intermetallic compound layer 3 made of an intermetallic compound of Cu and Sn is formed on a surface of a base material 2 made of Cu or a Cu alloy, and a Cu-Sn intermetallic compound is formed. An Sn layer 4 made of Sn or a Sn alloy is formed on the layer 3, and a partial film 5 is formed on a part of the surface of the Sn layer 4.
Specifically, the base material 2 is a strip formed in a strip shape, and the surface of the plated strip 6 on which the Cu-Sn intermetallic compound layer 3 and the Sn layer 4 are formed is shown in FIGS. As shown in FIG. 3, a partial film 5 is formed in a stripe shape along the length direction. 2 shows a connector terminal conductive member 1 used as a male terminal, and FIG. 3 shows a connector terminal conductive member 11 used as a female terminal.
Then, by press-forming the conductive members 1 and 11 for connector terminals, a plurality of terminals are continuously formed side by side in the length direction of the strip.
このコネクタ端子用導電部材１，１１にストライプ状に設けられる部分皮膜５は、端子に成形したときに端子同士が嵌合して接触状態となる予定の嵌合予定部位に形成されることを前提とするものであるが、リード線が圧着状態に接続される予定の圧着予定部位に形成しても良い。図２及び図３は、嵌合予定部位と圧着予定部位の両方に形成した例であり、以下、この例に基づいて説明する。この部分皮膜５は図１に示すように、めっき付条材６のＳｎ層４の上に形成されたＮｉ又はＮｉ合金からなるＮｉ層８と、Ｎｉ層８の上に形成されたＡｇ又はＡｇ合金からなるＡｇ層９とを有し、Ｓｎ層４とＮｉ層８との間、具体的にはＳｎ層４におけるＮｉ層８との界面部に、ＳｎにＮｉが固溶してなるＳｎ−Ｎｉ固溶体及び／又はＳｎとＮｉの金属間化合物を含有するＳｎ−Ｎｉ層７が形成されている。 It is assumed that the partial coating 5 provided on the connector terminal conductive members 1 and 11 in the form of a stripe is formed at a fitting site where the terminals are to be fitted into a contact state when the terminals are formed. However, the lead wire may be formed at a portion to be crimped where the lead wire is to be connected in a crimped state. FIG. 2 and FIG. 3 show examples in which both the fitting planned part and the crimping planned part are formed. Hereinafter, description will be made based on this example. As shown in FIG. 1, the partial film 5 includes a Ni layer 8 made of Ni or a Ni alloy formed on the Sn layer 4 of the plated strip 6 and an Ag or Ag formed on the Ni layer 8. An Ag layer 9 made of an alloy is provided. An Sn— layer in which Ni forms a solid solution in Sn is provided between the Sn layer 4 and the Ni layer 8, specifically, at the interface between the Sn layer 4 and the Ni layer 8. An Sn—Ni layer 7 containing a Ni solid solution and / or an intermetallic compound of Sn and Ni is formed.
図４に、このコネクタ用導電部材１、１１を使用して製造されたコネクタの一例を示す。
雄端子２１は、先端に、雌端子２２に嵌合状態に接触する嵌合部３１が形成され、その基端部にリード線圧着部３２が形成されている。嵌合部３１は棒状に形成され、リード線圧着部３２は、リード線３３の先端に露出している導体３３ａを嵌合する円筒部３４が嵌合部３１に連続して形成され、その円筒部３４に連続して、一対のかしめ片３５ａ，３５ｂが左右に開いた状態に一体に形成された構成とされている。これらかしめ片３５ａ，３５ｂは、符号３５ａがリード線３３の外被３３ｂをかしめる外被用かしめ片であり、符号３５ｂがリード線３３の導体３３ａをかしめる導体用かしめ片である。
FIG. 4 shows an example of a connector manufactured using the connector conductive members 1 and 11.
The male terminal 21 has a fitting portion 31 formed at the distal end to be in contact with the female terminal 22 in a fitted state, and a lead wire crimping portion 32 formed at a base end thereof. The fitting portion 31 is formed in a rod shape, and the lead wire crimping portion 32 is formed with a cylindrical portion 34 for fitting a conductor 33a exposed at the end of the lead wire 33 continuously to the fitting portion 31. A pair of caulking pieces 35a and 35b are formed integrally with the part 34 so as to be open to the left and right. In these caulking pieces 35a and 35b, the reference numeral 35a is a caulking piece for the sheath for caulking the jacket 33b of the lead wire 33, and the reference numeral 35b is a conductor caulking piece for caulking the conductor 33a of the lead wire 33.
雌端子２２は、先端に、雄端子２１の嵌合部３１を嵌合する嵌合部４１が形成され、その基端部にリード線圧着部４２が形成されている。嵌合部４１は、雄端子２１の嵌合部３１を緊密に嵌合し得る内径の円筒状に形成され、その先端部を除く中央部分に長さ方向に沿うスリットが周方向に間隔をおいて複数形成されることにより、弾性変形容易部４３とされている。リード線圧着部４２は、雄端子２１と同様に、リード線３３の先端の導体３３ａを嵌合する円筒部４４が嵌合部４１に連続して形成され、その円筒部４４に連続して、一対のかしめ片４５ａ，４５ｂが左右に開いた状態に一体に形成されており、符号４５ａは外被用かしめ片、符号４５ｂは導体用かしめ片である。 The female terminal 22 has a fitting part 41 for fitting the fitting part 31 of the male terminal 21 at the tip, and a lead wire crimping part 42 at the base end. The fitting portion 41 is formed in a cylindrical shape having an inside diameter capable of tightly fitting the fitting portion 31 of the male terminal 21, and a slit along a length direction is provided at a central portion excluding a tip end thereof at intervals in a circumferential direction. Thus, a plurality of elastic deformation portions 43 are formed. In the lead wire crimping portion 42, a cylindrical portion 44 for fitting the conductor 33a at the tip of the lead wire 33 is formed continuously with the fitting portion 41, similarly to the male terminal 21, and continuously with the cylindrical portion 44, A pair of caulking pieces 45a and 45b are integrally formed in a state where they are opened to the left and right, reference numeral 45a is a caulking piece for a jacket, and reference numeral 45b is a caulking piece for a conductor.
そして、雄端子２１では、前述したストライプ状の部分皮膜５が棒状の嵌合部３１の基端側に近い部分の外周面、円筒部３４の内面及び導体用かしめ片３５ｂの内面にそれぞれ配置されている。一方、雌端子２２では、ストライプ状の部分皮膜５が嵌合部４１の先端部の内周面、円筒部４４の内面及び導体用かしめ片４５ｂの内面にそれぞれ配置されている。
この部分皮膜の形成部位は、コネクタ端子用導電部材１，１１を端子に加工したときに、相手端子と嵌合して接触状態となる部位（嵌合予定部とする）及びリード線がかしめられて圧着状態に接続される部位（圧着予定部位とする）にそれぞれ形成され、この部分皮膜５が形成されていない部位は、Ｓｎ層４の表面が露出している。通常は、リード線圧着部３２，４２は、雄端子２１では嵌合部３１と反対面、雌端子２２では嵌合部４１と同じ面に形成される。したがって、雄端子２１に用いられるコネクタ用導電部材１では、図２に示すように部分皮膜５がめっき付条材６の両面に形成され、雌端子２２に用いられるコネクタ用導電部材１１では、図３に示すように、めっき付条材６の一方の面にのみ形成される。
なお、「嵌合予定部位」は、雄端子と雌端子とが直接面接触する部分にそれに隣接する若干のマージン幅の部分を加えた部位とするのが好適である。「圧着予定部位」も同様であり、リード線が圧着して接触する部分にそれに隣接する若干のマージン幅の部分を加えた部位とするのが好適である。
この様な個々のコネクタの雄端子２１及び雌端子２２が、雄端子毎、あるいは雌端子毎に複数本まとめてハウジングに収容されることにより多ピン型のコネクタとなる。
In the male terminal 21, the striped partial film 5 described above is disposed on the outer peripheral surface of the portion near the base end of the rod-shaped fitting portion 31, the inner surface of the cylindrical portion 34, and the inner surface of the conductor caulking piece 35b. ing. On the other hand, in the female terminal 22, the striped partial film 5 is disposed on the inner peripheral surface of the distal end portion of the fitting portion 41, the inner surface of the cylindrical portion 44, and the inner surface of the caulking piece 45b for the conductor.
When the conductive members 1 and 11 for connector terminals are processed into terminals, the portion where the partial film is formed is a portion that will be brought into contact with a mating terminal to be in a contact state (hereinafter referred to as a fitting portion) and a lead wire will be caulked. The portion where the partial coating 5 is not formed is formed at each of the portions that are connected in a press-bonded state (the portions to be press-bonded), and the surface of the Sn layer 4 is exposed. Normally, the lead wire crimping portions 32 and 42 are formed on the surface opposite to the fitting portion 31 in the male terminal 21 and on the same surface as the fitting portion 41 in the female terminal 22. Therefore, in the connector conductive member 1 used for the male terminal 21, the partial coating 5 is formed on both surfaces of the plated strip 6 as shown in FIG. 2, and in the connector conductive member 11 used for the female terminal 22, As shown in FIG. 3, it is formed only on one surface of the plated material 6.
The “fitting portion” is preferably a portion obtained by adding a portion having a slight margin width adjacent to the portion where the male terminal and the female terminal are in direct surface contact. The same applies to the “site to be press-bonded”, and it is preferable to set the portion to which a portion of the marginal width adjacent to the portion to which the lead wire comes into contact by pressing is added.
A plurality of male terminals 21 and female terminals 22 of such individual connectors are collectively housed in the housing for each male terminal or each female terminal, thereby forming a multi-pin connector.
以下、このコネクタ用導電部材１、１１の層構造の詳細について説明する。
基材２はコネクタ端子としての使用に適した銅又は銅合金であれば特に限定しないが、導電性、耐熱性、強度、加工性等を考慮すると、以下に列挙する各種銅合金を適用するのが好ましい。
（１）Ｍｇ：０．１５〜３．０質量％、Ｐ：０．０００５〜０．１質量％（Ｐは不可避不純物として存在する品種もある）、残部がＣｕおよび不可避的不純物である組成を有するＣｕ−Ｍｇ系合金であり、例えば三菱伸銅株式会社のＭＳＰシリーズ。
（２）Ｚｎ：２．０〜３２．５質量％、Ｓｎ：０．１〜０．９質量％、Ｎｉ：０．０５〜１．０質量％、Ｆｅ：０．００１〜０．１質量％、Ｐ：０．００５〜０．１質量％、残部がＣｕおよび不可避的不純物である組成を有するＣｕ−Ｚｎ系合金であり、例えば三菱伸銅株式会社のＭＮＥＸ１０。
（３）Ｃｒ：０．０７〜０．４質量％、Ｚｒ：０．０１〜０．１５質量％、Ｓｉ：０．００５〜０．１質量％、残部がＣｕおよび不可避的不純物である組成を有するＣｒ−Ｚｒ系銅合金であり、例えば三菱伸銅株式会社のＭＺＣ１。
（４）Ｚｒ：０．００５〜０．５質量％、残部がＣｕおよび不可避的不純物である組成を有する銅合金であり、例えば三菱伸銅株式会社のＣ１５１。
Hereinafter, the details of the layer structure of the conductive members 1 and 11 for the connector will be described.
The base material 2 is not particularly limited as long as it is copper or a copper alloy suitable for use as a connector terminal. In consideration of conductivity, heat resistance, strength, workability, and the like, various copper alloys listed below are applied. Is preferred.
(1) Mg: 0.15 to 3.0% by mass, P: 0.0005 to 0.1% by mass (P is a kind that exists as inevitable impurities), and the balance is Cu and inevitable impurities. For example, MSP series of Mitsubishi Shindoh Co., Ltd.
(2) Zn: 2.0 to 32.5 mass%, Sn: 0.1 to 0.9 mass%, Ni: 0.05 to 1.0 mass%, Fe: 0.001 to 0.1 mass% , P: 0.005 to 0.1 mass%, the balance being Cu and a Cu—Zn-based alloy having a composition of inevitable impurities, for example, MNEX10 of Mitsubishi Shindoh Co., Ltd.
(3) Cr: 0.07 to 0.4% by mass, Zr: 0.01 to 0.15% by mass, Si: 0.005 to 0.1% by mass, the balance being Cu and inevitable impurities. For example, MZC1 of Mitsubishi Shindoh Co., Ltd.
(4) Zr: a copper alloy having a composition of 0.005 to 0.5% by mass, with the balance being Cu and inevitable impurities, for example, C151 of Mitsubishi Shindoh Co., Ltd.
（５）Ｆｅ：０．０５〜０．１５質量％、Ｐ：０．０１５〜０．０５質量％、残部がＣｕおよび不可避的不純物である組成を有するＦｅ−Ｐ系銅合金であり、例えば三菱伸銅株式会社のＴＡＭＡＣ４。
（６）Ｆｅ：２．１〜２．６質量％、Ｚｎ：０．０５〜０．２０質量％、Ｐ：０．０１５〜０．１５質量％、残部がＣｕおよび不可避的不純物である組成を有するＦｅ−Ｚｎ系銅合金であり、例えば三菱伸銅株式会社のＴＡＭＡＣ１９４。
（７）Ｎｉ：１．０〜５．０質量％、Ｓｉ：０．１〜１．５質量％、Ｍｇ，Ｓｎ，Ｚｎのうち１種類または２種類以上を合計で０．０１〜２．０質量％、残部がＣｕおよび不可避的不純物である組成を有するＣｕ−Ｎｉ−Ｓｉ系合金（コルソン系合金）であり、例えば三菱伸銅株式会社のＭＡＸシリーズ。
これらの銅合金は、良好な熱伝導性、強度、熱クリープ性、耐熱性、加工性等を有しており、電気自動車用のコネクタ製造用銅合金条材として最適である。
(5) Fe-P-based copper alloy having a composition in which Fe: 0.05 to 0.15% by mass, P: 0.015 to 0.05% by mass, and the balance being Cu and unavoidable impurities. TAMAC4 of Shinshindo Co., Ltd.
(6) Fe: 2.1 to 2.6% by mass, Zn: 0.05 to 0.20% by mass, P: 0.015 to 0.15% by mass, with the balance being Cu and inevitable impurities. Fe-Zn-based copper alloy, for example, TAMAC194 of Mitsubishi Shindoh Co., Ltd.
(7) Ni: 1.0 to 5.0% by mass, Si: 0.1 to 1.5% by mass, one or more of Mg, Sn and Zn in a total of 0.01 to 2.0. It is a Cu-Ni-Si-based alloy (Corson-based alloy) having a composition of mass%, the balance being Cu and unavoidable impurities, for example, the MAX series of Mitsubishi Shindoh Co., Ltd.
These copper alloys have good thermal conductivity, strength, heat creep properties, heat resistance, workability, and the like, and are most suitable as copper alloy strips for manufacturing connectors for electric vehicles.
Ｃｕ−Ｓｎ金属間化合物層３及びＳｎ層４は、基材２の上にＣｕ又はＣｕ合金からなるＣｕめっき層及びＳｎ又はＳｎ合金からなるＳｎめっき層を順に形成した後に加熱してリフロー処理することによって形成されたものであり、Ｃｕ６Ｓｎ５やＣｕ３Ｓｎ等の金属間化合物を主成分とする。Ｃｕ−Ｓｎ金属間化合物層３の平均厚みは０．１μｍ以上３．０μｍ以下が好ましく、Ｓｎ層４の平均厚みは０．１μｍ以上５．０μｍ以下が好ましい。このＣｕ−Ｓｎ金属間化合物層３とＳｎ層４との界面は凹凸形状に形成される。基材２とＣｕ−Ｓｎ金属間化合物層３との間に薄くＣｕ層が形成される場合もある。 The Cu-Sn intermetallic compound layer 3 and the Sn layer 4 are subjected to reflow treatment by heating after sequentially forming a Cu plating layer made of Cu or Cu alloy and a Sn plating layer made of Sn or Sn alloy on the base material 2. The main component is an intermetallic compound such as Cu 6 Sn 5 or Cu 3 Sn. The average thickness of the Cu—Sn intermetallic compound layer 3 is preferably 0.1 μm or more and 3.0 μm or less, and the average thickness of the Sn layer 4 is preferably 0.1 μm or more and 5.0 μm or less. The interface between the Cu-Sn intermetallic compound layer 3 and the Sn layer 4 is formed in an uneven shape. A thin Cu layer may be formed between the base material 2 and the Cu-Sn intermetallic compound layer 3.
ストライプ状の部分皮膜５において、Ｓｎ層４の上に形成されているＳｎ−Ｎｉ層７、Ｎｉ層８及びＡｇ層９は、リフロー処理した後のＳｎ層４の表面における嵌合予定部位及び圧着予定部位に、Ｎｉ又はＮｉ合金からなるＮｉめっき、Ａｇ又はＡｇ合金からなるＡｇめっきを施した後に加熱処理することにより形成されたものである。 In the striped partial film 5, the Sn—Ni layer 7, the Ni layer 8, and the Ag layer 9 formed on the Sn layer 4 are to be fitted on the surface of the Sn layer 4 after the reflow treatment and to be pressed. It is formed by applying a Ni plating made of Ni or a Ni alloy or an Ag plating made of Ag or an Ag alloy to a predetermined portion and then performing a heat treatment.
Ｓｎ−Ｎｉ層７は、Ｓｎ層４とＮｉ層８との界面近傍のＳｎ層４側に形成され、Ｓｎ（結晶構造が正方晶のβ錫）にＮｉが固溶してなるＳｎ−Ｎｉ固溶体及び／又はＳｎとＮｉとの金属間化合物を含有している。Ｓｎ−Ｎｉ層７中のＮｉの含有量は５ａｔ％以上が好ましい。Ｎｉ含有量の上限は６７ａｔ％が好ましい。より好ましくは７ａｔ％以上６０ａｔ％以下、さらに好ましくは１０ａｔ％以上５０ａｔ％以下である。
また、このＳｎ−Ｎｉ層７の平均厚みは０．０２μｍ以上１μｍ以下が好ましい。また、Ｓｎ−Ｎｉ固溶体及び／又はＳｎ−Ｎｉ金属間化合物の平均粒径は０．２μｍ以上５μｍ以下である。
The Sn—Ni layer 7 is formed on the Sn layer 4 side near the interface between the Sn layer 4 and the Ni layer 8, and is a Sn—Ni solid solution in which Ni is dissolved in Sn (β-tin having a tetragonal crystal structure). And / or contains an intermetallic compound of Sn and Ni. The content of Ni in the Sn—Ni layer 7 is preferably 5 at% or more. The upper limit of the Ni content is preferably 67 at%. More preferably, it is 7 at% or more and 60 at% or less, and further preferably, 10 at% or more and 50 at% or less.
The average thickness of the Sn—Ni layer 7 is preferably 0.02 μm or more and 1 μm or less. The average particle size of the Sn—Ni solid solution and / or the Sn—Ni intermetallic compound is 0.2 μm or more and 5 μm or less.
Ｎｉ層８は、その平均厚みが０．２μｍ以上１０μｍ以下が好ましい。また、基材２の圧延面に対する法線方向から視た平均結晶粒径が１０ｎｍ以上５００ｎｍ以下であり、平均結晶粒径の変動係数が１以下である。平均結晶粒径の変動係数とは、平均結晶粒径の標準偏差を平均結晶粒径で割った値である。平均結晶粒径は５０ｎｍ以上１００ｎｍ以下がより好ましく、変動係数は０．３以下がより好ましい。
また、このＮｉ層８において、基材２の圧延面の法線方向から視た平均結晶粒径をｄＮＤとし、基材２の圧延幅方向に対して垂直な面での平均結晶粒径をｄＴＤとすると、その比ｄＴＤ／ｄＮＤが１以上１０以下である。さらに、このＮｉ層８においてＡｇ層９と接する面のＩＳＯ２５１７８に準拠した算術平均面高さＳａは０．５μｍ以下である。平均結晶粒径の比ｄＴＤ／ｄＮＤは１以上６以下がより好ましく、算術平均面高さＳａは０．２μｍ以下がより好ましい。
The average thickness of the Ni layer 8 is preferably 0.2 μm or more and 10 μm or less. Further, the average crystal grain size viewed from the normal direction to the rolled surface of the base material 2 is 10 nm or more and 500 nm or less, and the coefficient of variation of the average crystal grain size is 1 or less. The variation coefficient of the average crystal grain size is a value obtained by dividing the standard deviation of the average crystal grain size by the average crystal grain size. The average crystal grain size is more preferably 50 nm or more and 100 nm or less, and the coefficient of variation is more preferably 0.3 or less.
In the Ni layer 8, the average crystal grain size as viewed from the normal direction of the rolled surface of the base material 2 is d ND, and the average crystal grain size in a plane perpendicular to the rolling width direction of the base material 2 is When d TD, the ratio d TD / d ND is 1 to 10. Further, the arithmetic average surface height Sa of the surface of the Ni layer 8 which is in contact with the Ag layer 9 according to ISO25178 is 0.5 μm or less. The ratio d TD / d ND of the average crystal grain size is more preferably 1 or more and 6 or less, and the arithmetic mean surface height Sa is more preferably 0.2 μm or less.
Ａｇ層９は、その平均厚みが０．５μｍ以上２０μｍ以下が好ましい。また、このＡｇ層９の表面硬さは、コネクタ端子としての使用時の耐久性、特に耐摩耗性の低下を抑制するために、ビッカース硬さで１３０Ｈｖ以上が好ましい。２５０Ｈｖを超えても、効果は飽和し、コスト高になるため無駄である。
なお、Ａｇ層もＮｉ層も厚い方が耐摩耗性は良くなるが、あまり厚くしても効果は飽和してしまうためコスト的にメリットがなく、逆に厚過ぎると曲げの際に割れる恐れが増大することから、Ａｇ層とＮｉ層の合計厚さは、１μｍ以上２０μｍ以下の範囲とすることが好ましい。
The Ag layer 9 preferably has an average thickness of 0.5 μm or more and 20 μm or less. Further, the surface hardness of the Ag layer 9 is preferably 130 Vv or more in terms of Vickers hardness in order to suppress a decrease in durability when used as a connector terminal, particularly, abrasion resistance. Even if it exceeds 250 Hv, the effect is saturated and the cost is increased, so that it is useless.
The thicker the Ag layer and the better the Ni layer, the better the abrasion resistance. However, if the thickness is too large, the effect is saturated, so there is no merit in terms of cost. In view of the increase, the total thickness of the Ag layer and the Ni layer is preferably in the range of 1 μm to 20 μm.
このような層構造を有するコネクタ端子用導電部材１，１１は、基材２の表面にＣｕめっき、Ｓｎめっきを順に施した後に、リフロー処理し、リフロー処理後のＳｎ層４の上に、Ｎｉめっき、Ａｇめっきを順に施して、その後、加熱処理することにより形成される。 The connector terminal conductive members 1 and 11 having such a layer structure are subjected to reflow treatment after Cu plating and Sn plating are sequentially applied to the surface of the base material 2, and Ni is placed on the Sn layer 4 after the reflow treatment. It is formed by sequentially performing plating and Ag plating, and then performing heat treatment.
Ｃｕめっきは一般的なＣｕめっき浴を用いればよく、例えば硫酸銅（ＣｕＳＯ４）及び硫酸（Ｈ２ＳＯ４）を主成分とした硫酸銅浴等を用いることができる。めっき浴の温度は２０〜５０℃、電流密度は１〜５０Ａ／ｄｍ２とされる。このＣｕめっきにより形成されるＣｕめっき層の膜厚は０．０５μｍ以上０．５０μｍ以下とされる。 For Cu plating, a general Cu plating bath may be used, and for example, a copper sulfate bath containing copper sulfate (CuSO 4 ) and sulfuric acid (H 2 SO 4 ) as main components can be used. The temperature of the plating bath is 20 to 50 ° C., and the current density is 1 to 50 A / dm 2 . The film thickness of the Cu plating layer formed by the Cu plating is 0.05 μm or more and 0.50 μm or less.
Ｓｎめっき層形成のためのめっき浴としては、一般的なＳｎめっき浴を用いればよく、例えば硫酸（Ｈ２ＳＯ４）と硫酸第一錫（ＳｎＳＯ４）を主成分とした硫酸浴を用いることができる。めっき浴の温度は１５〜３５℃、電流密度は１〜３０Ａ／ｄｍ２とされる。このＳｎめっき層の膜厚は０．１μｍ以上５．０μｍ以下とされる。 As a plating bath for forming a Sn plating layer, a general Sn plating bath may be used. For example, a sulfuric acid bath containing sulfuric acid (H 2 SO 4 ) and stannous sulfate (SnSO 4 ) as main components may be used. Can be. The temperature of the plating bath is 15 to 35 ° C., and the current density is 1 to 30 A / dm 2 . The film thickness of this Sn plating layer is 0.1 μm or more and 5.0 μm or less.
リフロー処理はＣｕめっき層及びＳｎめっき層を加熱して一旦溶融させたのち急冷すればよい。例えば、ＣＯ還元性雰囲気にした加熱炉内でＣｕめっき及びＳｎめっきを施した後の処理材を２０〜７５℃／秒の昇温速度で２４０〜３００℃のピーク温度まで加熱する加熱工程と、そのピーク温度に達した後、３０℃／秒以下の冷却速度で２〜１０秒間冷却する一次冷却工程と、一次冷却後に１００〜２５０℃／秒の冷却速度で２０〜６０℃まで冷却する二次冷却工程とを有する処理とする。このリフロー処理により、基材２表面から順に、Ｃｕ−Ｓｎ金属間化合物層３、Ｓｎ層４が形成されためっき付条材６が形成される。基材２とＣｕ−Ｓｎ金属間化合物層３との間にＣｕめっき層の一部が残る場合もある。 In the reflow treatment, the Cu plating layer and the Sn plating layer may be heated and once melted, and then rapidly cooled. For example, a heating step of heating the treated material after performing Cu plating and Sn plating in a heating furnace in a CO reducing atmosphere to a peak temperature of 240 to 300 ° C. at a temperature increasing rate of 20 to 75 ° C./sec. After reaching the peak temperature, a primary cooling step of cooling at a cooling rate of 30 ° C./sec or less for 2 to 10 seconds, and a secondary cooling step of cooling to 20 to 60 ° C. at a cooling rate of 100 to 250 ° C./sec after the primary cooling. A process including a cooling step. By this reflow treatment, the plated strip 6 on which the Cu-Sn intermetallic compound layer 3 and the Sn layer 4 are formed in order from the surface of the substrate 2 is formed. A part of the Cu plating layer may remain between the base material 2 and the Cu-Sn intermetallic compound layer 3 in some cases.
Ｎｉめっきは一般的なＮｉめっき浴を用いればよく、例えば硫酸（Ｈ２ＳＯ４）と硫酸ニッケル（ＮｉＳＯ４）を主成分とした硫酸浴を用いることができる。めっき浴の温度は２０℃以上６０℃以下、電流密度は５〜６０Ａ/ｄｍ２以下とされる。このＮｉめっき層の膜厚は通常０．０５μｍ以上２０μｍ以下とされるが、本発明では０．２μｍ以上１０μｍ以下の範囲で調整される。
このＮｉめっきを施す前に、Ｓｎ層４の表面に薄くストライクめっき（フラッシュめっき）を例えば０．００５μｍ以上０．２μｍ以下の厚みで施しても良い。ストライクめっきとしては、金、銀、ニッケル等を適用できる。
Ａｇめっきは、一般的なＡｇめっき浴であるシアン化銀めっき浴を用いればよい。浴の温度は１５℃以上３５℃以下、電流密度は０．１Ａ／ｄｍ２以上３Ａ／ｄｍ２以下が適切である。このＡｇめっき層の膜厚は通常０．１μｍ以上５０μｍ以下とされるが、本発明では０．５μｍ以上２０μｍ以下の範囲で調整される。
For Ni plating, a general Ni plating bath may be used. For example, a sulfuric acid bath containing sulfuric acid (H 2 SO 4 ) and nickel sulfate (NiSO 4 ) as main components can be used. The temperature of the plating bath is from 20 ° C. to 60 ° C., and the current density is from 5 to 60 A / dm 2 . The thickness of the Ni plating layer is usually 0.05 μm or more and 20 μm or less, but is adjusted in the range of 0.2 μm or more and 10 μm or less in the present invention.
Before performing the Ni plating, a thin strike plating (flash plating) may be performed on the surface of the Sn layer 4 with a thickness of, for example, 0.005 μm or more and 0.2 μm or less. Gold, silver, nickel or the like can be applied as strike plating.
For the Ag plating, a silver cyanide plating bath that is a general Ag plating bath may be used. The temperature of the bath 15 ℃ than 35 ° C. or less, the current density is 0.1 A / dm 2 or more 3A / dm 2 or less is appropriate. The thickness of the Ag plating layer is usually 0.1 μm or more and 50 μm or less, but is adjusted in the range of 0.5 μm or more and 20 μm or less in the present invention.
これらＮｉめっき及びＡｇめっきを施した後、５０℃以上２３０℃以下の温度で１秒以上１０分以下の時間保持する加熱処理を行う。この加熱処理により、Ｓｎ層４側のＮｉ層８との界面に、Ｓｎ層４とＮｉ層８との間でＳｎの一部にＮｉが固溶してなるＳｎ−Ｎｉ固溶体及び／又はＳｎとＮｉとの金属間化合物が層状に配置されたＳｎ−Ｎｉ層７が形成される。 After performing the Ni plating and the Ag plating, a heat treatment is performed at a temperature of 50 ° C. to 230 ° C. for 1 second to 10 minutes. By this heat treatment, at the interface between the Sn layer 4 and the Ni layer 8, an Sn—Ni solid solution and / or Sn in which Ni is partially dissolved in a part of Sn between the Sn layer 4 and the Ni layer 8 are formed. The Sn—Ni layer 7 in which the intermetallic compound with Ni is arranged in a layer is formed.
以上の層構造を有するコネクタ端子用導電部材１，１１は、所定の外形にプレス打抜きされ、曲げ加工等の機械的加工が施されて、雄端子２１あるいは雌端子２２となり、耐久性が高く、密着力が強くて硬度の高い部分皮膜５が、雄端子２１と雌端子２２との嵌合部３１，４１に形成される。これにより、繰り返し挿抜に対する高い耐久性を有することができ、特に、厳しい状況下で使用される電気自動車用充電器コネクタの製造に使用されることが好ましい。
更に、リード線圧着部３２，４２にも部分皮膜５が形成されてもよい。これにより、端子全体としての強度および耐久性が増し、外部リード線３３とのはんだ付けなどの接合が容易になる。この外部リード線３３と接合する部位は、かしめ加工などを施されることが多く、密着力が強固である部分皮膜５が形成されることにより、加工性が向上する。この場合、このリード線圧着部３２，４２に形成される部分皮膜５の厚みは、雄端子２１と雌端子２２との直接の挿抜力が作用しないので、コストダウンの面からも、嵌合部３１，４１に形成される部分皮膜５の厚みより小さくても良い。
The connector terminal conductive members 1 and 11 having the above-described layer structure are press-punched into a predetermined outer shape and subjected to mechanical processing such as bending to become the male terminal 21 or the female terminal 22 and have high durability. The partial film 5 having high adhesion and high hardness is formed on the fitting portions 31 and 41 between the male terminal 21 and the female terminal 22. Thereby, it is possible to have a high durability against repeated insertion and removal, and it is particularly preferable to use it for manufacturing a battery charger connector for an electric vehicle used under severe conditions.
Further, the partial coating 5 may also be formed on the lead wire crimping portions 32 and 42. As a result, the strength and durability of the terminal as a whole are increased, and joining such as soldering to the external lead wire 33 becomes easy. The portion to be joined to the external lead wire 33 is often subjected to caulking or the like, and the partial film 5 having strong adhesion is formed, thereby improving workability. In this case, the thickness of the partial coating 5 formed on the lead wire crimping portions 32 and 42 is small because the direct insertion / extraction force between the male terminal 21 and the female terminal 22 does not act. The thickness may be smaller than the thickness of the partial coating 5 formed on the bases 31 and 41.
長さ５００ｍｍ、幅３０ｍｍ、厚み０．３ｍｍの三菱伸銅株式会社製の商品名「ＭＳＰ１」（Ｍｇ：０.３〜２質量％、Ｐ：０.００１〜０.１質量％、残部がＣｕおよび不可避的不純物）を用いた基材の表面に、以下のめっき条件で、０．４μｍ厚みのＣｕめっき及び１．２μｍ厚みのＳｎめっきを順に施した後に、前述したリフロー処理を施して、めっき付条材を作製した。
（Ｃｕめっき条件）
処理方法：電解めっき
めっき液：硫酸銅めっき液
液温：２７℃
電流密度：４Ａ／ｄｍ2
（Ｓｎめっき条件）
処理方法：電解めっき
めっき液：硫酸錫めっき液
液温：２０℃
電流密度：２Ａ／ｄｍ2
Trade name "MSP1" manufactured by Mitsubishi Shindoh Co., Ltd. having a length of 500 mm, a width of 30 mm, and a thickness of 0.3 mm (Mg: 0.3 to 2% by mass, P: 0.001 to 0.1% by mass, the balance being Cu And unavoidable impurities) on the surface of the substrate under the following plating conditions, followed by Cu plating of 0.4 μm thickness and Sn plating of 1.2 μm thickness, followed by the reflow treatment described above. An additional material was produced.
(Cu plating conditions)
Treatment method: Electroplating Plating solution: Copper sulfate plating solution Temperature: 27 ° C
Current density: 4 A / dm 2
(Sn plating conditions)
Treatment method: Electroplating Plating solution: Tin sulfate plating solution Temperature: 20 ° C
Current density: 2 A / dm 2
次に、そのめっき付条材の所定の部位に、銀のストライクめっきを施した後、表１に示す厚みでＮｉめっき及びＡｇめっきを順に形成した。Ｎｉめっきは半光沢ニッケルめっきとした。これらのめっきを施した後、温風を吹き付けながら１５０℃の温度で１分間保持する加熱処理を行った。
この部分皮膜用の各めっきの条件は以下の通りとした。
（銀ストライクめっき条件）
処理方法：電解めっき
めっき液：シアン化銀ストライクめっき液
液温：室温
電流密度：３Ａ／ｄｍ2
（Ｎｉめっき条件)
処理方法：電解めっき
めっき液：スルファミン酸ニッケルめっき液
液温：５０℃
電流密度：１０Ａ／ｄｍ2
（Ａｇめっき）
処理方法：電解めっき
めっき液：シアン化銀めっき液
液温：３０℃
電流密度：１Ａ／ｄｍ2
Next, a predetermined portion of the plated material was subjected to silver strike plating, and then Ni plating and Ag plating were formed in the order shown in Table 1 in order. Ni plating was semi-bright nickel plating. After performing these platings, a heat treatment was performed at a temperature of 150 ° C. for 1 minute while blowing hot air.
The conditions of each plating for this partial film were as follows.
(Silver strike plating conditions)
Treatment method: Electroplating plating solution: Silver cyanide strike plating solution Temperature: Room temperature Current density: 3 A / dm 2
(Ni plating conditions)
Treatment method: Electroplating plating solution: Nickel sulfamate plating solution Temperature: 50 ° C
Current density: 10 A / dm 2
(Ag plating)
Treatment method: electrolytic plating plating solution: silver cyanide plating solution temperature: 30 ° C
Current density: 1 A / dm 2
得られた各試料について、Ｎｉ層における平均結晶粒径、変動係数、ｄＴＤ／ｄＮＤの粒径比、Ａｇ層と接する面の算術平均面高さＳａを測定し、また、Ｓｎ−Ｎｉ層における平均粒径、Ｓｎ−Ｎｉ層中のＮｉの含有量（ａｔ％）を測定した。
Ｎｉ層における平均結晶粒径は、試料断面のＳＥＭ画像より切断法にて１００個の結晶粒径を算出し、これを平均した。その平均結晶粒径の標準偏差を平均結晶粒径で割ることで変動係数を求めた。
ｄＴＤ／ｄＮＤの粒径比は、基材の圧延面の法線方向から視た平均結晶粒径ｄＮＤ、及び基材の圧延幅方向に対して垂直な面での平均結晶粒径ｄＴＤをそれぞれＳＥＭ画像により切断法にて算出し、その比率を求めた。
算術平均面高さは、ＩＳＯ２５１７８に従い、レーザー共焦点顕微鏡（ＬＳＣＭ）にて測定した。
Ｓｎ−Ｎｉ層における平均粒径は、ＳＥＭ−ＥＰＭＡによりＳｎ−Ｎｉ固溶体及び／又はＳｎ−Ｎｉ金属間化合物を確認した後、ＳＥＭ−ＥＢＳＤにより結晶粒界像を撮影し、１００個の結晶粒径から算出した。
Ｓｎ−Ｎｉ層のＮｉの含有量（ａｔ％）は、ＴＥＭ−ＥＤＸによりＳｎ−Ｎｉ層の任意の５点で測定した値から算出した。
For each of the obtained samples, the average crystal grain size in the Ni layer, the coefficient of variation, the particle size ratio of d TD / d ND , and the arithmetic average surface height Sa of the surface in contact with the Ag layer were measured. Were measured for the average particle size and the content (at%) of Ni in the Sn-Ni layer.
The average crystal grain size in the Ni layer was obtained by calculating 100 crystal grain sizes from the SEM image of the sample cross section by a cutting method, and averaging the calculated crystal grain sizes. The coefficient of variation was determined by dividing the standard deviation of the average grain size by the average grain size.
The grain size ratio of d TD / d ND is determined by the average grain size d ND as viewed from the normal direction of the rolled surface of the base material and the average grain size d d in the surface perpendicular to the rolling width direction of the base material. The TD was calculated by a cutting method using SEM images, and the ratio was determined.
The arithmetic mean plane height was measured by a laser confocal microscope (LSCM) according to ISO25178.
The average grain size of the Sn—Ni layer was determined by confirming the Sn—Ni solid solution and / or Sn—Ni intermetallic compound by SEM-EPMA, and then taking a grain boundary image by SEM-EBSD to obtain 100 grain sizes. Calculated from
The Ni content (at%) of the Sn—Ni layer was calculated from values measured at five arbitrary points of the Sn—Ni layer by TEM-EDX.
これらの試料につき、部分皮膜の表面硬さを測定し、耐摩耗性、曲げ加工性を評価した。
表面硬さは、加熱前と、実装時を想定した条件（１５０℃×１０００ｈｒ）で加熱保持処理後について、マイクロビッカース硬度計にて測定した。
耐摩耗性（摺動試験）は、山崎精機研究所製精密摺動試験装置ＣＲＳ−Ｇ２０５０−ＭＴＳ型を使用し、摺動距離０．２５ｍｍ、摺動速度０．５ｍｍ／ｓ、接触荷重１．２Ｎ、摺動回数５００往復を１セットとし、これを複数セット繰り返す条件で摺動回数と接触抵抗との関係を評価した。サンプル数は３個とし、サンプルの初期（試験開始前）の接触抵抗が１ｍΩ以下であることを確認した後、連続的に摺動させながら接触抵抗を測定し、接触抵抗が５０ｍΩ以上となったのが何セット目であるかに基づき、良否を判定した。具体的には、５０ｍΩに到達したセット数について、３個とも１０セット目（４５０１〜５０００往復）以降であったものを「優」、いずれか１個でも９セット目であった（ただし、それを含め全て９セット目以降であった）場合は「良」、いずれか１個でも８セット目であった（ただし、それを含め全て８セット目以降であった）場合は「可」とし、いずれか１個でも７セット目以前で５０ｍΩに達してしまったものがあった場合は「不可」とした。
曲げ加工性は、試料をＢａｄＷａｙ：圧延垂直方向に幅１０ｍｍ×長さ６０ｍｍに切出し、ＪＩＳ Ｚ ２２４８に規定される金属材料曲げ試験方法に準拠し、曲げ半径Ｒと押し金具の厚さｔとの比Ｒ／ｔ＝１として１８０°曲げ試験を行い、曲げ部の表面及び断面にクラック等が認められるか否かを光学顕微鏡にて倍率５０倍で観察した。クラック等が認められず、表面状態も曲げの前後で大きな変化がなかったものを「◎」、表面は光沢低下などの状態変化が認められたもののクラックの発生は確認できなかったものを「〇」、クラックは認められたものの、めっき剥離は認められなかったものを「△」、めっき自体の剥離が認められたものを「×」とした。
これらの結果を表２に示す。
The surface hardness was measured by a micro Vickers hardness tester before and after the heating and holding treatment under the conditions (150 ° C. × 1000 hr) assuming the time of mounting.
Abrasion resistance (sliding test) was measured using a precision sliding tester CRS-G2050-MTS type manufactured by Yamazaki Seiki Laboratories, with a sliding distance of 0.25 mm, a sliding speed of 0.5 mm / s, and a contact load of 1. The relationship between the number of times of sliding and the contact resistance was evaluated under the condition that 2N, 500 times of sliding times were set as one set, and this set was repeated plural times. The number of samples was three, and after confirming that the initial contact resistance of the sample (before the start of the test) was 1 mΩ or less, the contact resistance was measured while continuously sliding, and the contact resistance became 50 mΩ or more. The pass / fail was determined based on the number of the set. More specifically, as for the number of sets that reached 50 mΩ, all of the three sets after the tenth set (4501 to 5000 reciprocations) were “excellent”, and any one was the ninth set (however, , If all were in the ninth and subsequent sets), "Good", and if any one of them was in the eighth set (but all were in the eighth and subsequent sets), "OK" If any one of them reached 50 mΩ before the seventh set, it was judged as “impossible”.
The bending workability was determined by cutting a sample to a width of 10 mm and a length of 60 mm in a direction perpendicular to the rolling direction of the metal material and measuring the bending radius R and the thickness t of the press fitting in accordance with the metal material bending test method specified in JIS Z 2248. A 180 ° bending test was performed with the ratio R / t = 1, and whether or not cracks or the like were observed on the surface and cross section of the bent portion was observed with an optical microscope at a magnification of 50 ×. "◎" indicates that no cracks or the like were observed and the surface state did not change significantly before and after bending, and "」 "indicates that the surface showed a state change such as a decrease in gloss but no crack was observed. ”, Cracks were observed, but no peeling of the plating was observed, and“ △ ”was observed when peeling of the plating itself was observed.
Table 2 shows the results.
これらの結果より、本実施例はいずれも、長時間の加熱後も表面硬さは概ね１３０Ｈｖ以上であり、かつ良好な耐摩耗性（高い摺動回数）を示していると共に、曲げ加工性にも優れていることが分かる。
これに対し比較例を見ると、Ｎｉの結晶粒径が小さすぎる比較例Ｂ１とＢ２では、結晶粒が微細であるがゆえに耐摩耗性は良好であるが、硬くなりすぎるために曲げ加工性は悪かった。逆に結晶粒が５００ｎｍ前後と大きくなり、変動係数が１を超えてしまった実施例Ｂ３〜Ｂ６では、耐摩耗性が非常に悪い結果となった。比較例Ｂ７とＢ８はＳｎ−Ｎｉ化合物の形成が認められなかったもので、耐摩耗性は良好であったものの曲げ加工性が悪く、やはり密着性に問題があったものと思われる。比較例Ｂ９はわずかであるが変動係数が１を超え、かつＳｎ−Ｎｉ中のＮｉ量が多すぎるため、硬くなりすぎて割れが発生した。比較例Ｂ１０は、変動係数が１を超え、耐摩耗性が悪くなる結果となった。比較例Ｂ１１は、変動係数が１を超えており、またＮｉめっきとＡｇめっきの合計膜厚が０．６μｍと薄いために、耐摩耗性が悪くなった。比較例Ｂ１２は、逆にＮｉが厚くなり過ぎ、割れやすくなってしまった。また、比較例全体を見ると、半数が加熱後の表面硬さが１３０を下回っており、そのうちの多くは耐摩耗性も低下していた。
図５は試料Ａ４の断面写真であり、基材の上に、Ｃｕ３Ｓｎ及びＣｕ６Ｓｎ５からなるＣｕ−Ｓｎ金属間化合物層、Ｓｎ層、Ｎｉ層、Ａｇ層が順に形成され、Ｎｉ層とＳｎ層との界面にＳｎ−Ｎｉ層が形成されているのがわかる。
From these results, in each of the examples, the surface hardness was approximately 130 Hv or more even after heating for a long time, good wear resistance (high sliding frequency), and bending workability was observed. It can be seen that is also excellent.
On the other hand, according to the comparative examples, in comparative examples B1 and B2 in which the crystal grain size of Ni is too small, the wear resistance is good because the crystal grains are fine, but the bending workability is too high because the hardness is too hard. It was bad. Conversely, in Examples B3 to B6, in which the crystal grains were as large as about 500 nm and the variation coefficient exceeded 1, the results were very poor in abrasion resistance. In Comparative Examples B7 and B8, formation of a Sn—Ni compound was not observed, and although the abrasion resistance was good, the bending workability was poor, and it seems that there was also a problem in the adhesion. In Comparative Example B9, although the coefficient of variation was slight, the coefficient of variation exceeded 1, and the amount of Ni in Sn—Ni was too large, so that it became too hard and cracked. In Comparative Example B10, the coefficient of variation exceeded 1, resulting in poor wear resistance. In Comparative Example B11, the coefficient of variation exceeded 1, and the wear resistance was poor because the total thickness of the Ni plating and the Ag plating was as thin as 0.6 μm. In Comparative Example B12, on the other hand, Ni was too thick, and it was easily broken. In addition, looking at the entire comparative example, half showed that the surface hardness after heating was less than 130, and most of them also had reduced wear resistance.
FIG. 5 is a cross-sectional photograph of Sample A4, in which a Cu—Sn intermetallic compound layer composed of Cu 3 Sn and Cu 6 Sn 5 , a Sn layer, a Ni layer, and an Ag layer are sequentially formed on a substrate, and a Ni layer It can be seen that a Sn-Ni layer is formed at the interface between the Sn layer and the Sn layer.
１、１１ コネクタ端子用導電部材
２ 基材
３ Ｃｕ−Ｓｎ金属間化合物層
４ Ｓｎ層
５ 部分皮膜
６ めっき付条材
７ Ｓｎ−Ｎｉ層
８ Ｎｉ層
９ Ａｇ層
３１，４１ 嵌合部
３２，４２ リード線圧着部
４３ 弾性変形容易部
３４，４４ 円筒部
３５ａ，４５ａ 外被用かしめ片
３５ｂ，４５ｂ 導体用かしめ片
DESCRIPTION OF SYMBOLS 1, 11 Conductive member for connector terminals 2 Base material 3 Cu-Sn intermetallic compound layer 4 Sn layer 5 Partial film 6 Plated material 7 Sn-Ni layer 8 Ni layer 9 Ag layer 31, 41 Fitting part 32, 42 Lead wire crimping part 43 Elastic deformation part 34, 44 Cylindrical part 35a, 45a Caulking piece for jacket 35b, 45b Caulking piece for conductor
Claims (7)
前記Ｓｎ層における前記Ｎｉ層との界面部に、ＳｎにＮｉが固溶してなるＳｎ−Ｎｉ固溶体及び／又はＳｎとＮｉとの金属間化合物を含有するＳｎ−Ｎｉ層が形成され、
前記Ｎｉ層における前記基材の圧延面に対する法線方向から視た平均結晶粒径が１０ｎｍ以上５００ｎｍ以下であり、該平均結晶粒径の変動係数が１以下であることを特徴とするコネクタ端子用導電部材。 A Cu-Sn intermetallic compound layer composed of an intermetallic compound of Cu and Sn is formed on a substrate composed of Cu or Cu alloy, and Sn composed of Sn or a Sn alloy is formed on the Cu-Sn intermetallic compound layer. A layer is formed, and on the surface of the Sn layer, a partial film is formed in a stripe shape at a portion where the terminals are to be brought into contact by fitting when the terminals are molded, and a partial coating is formed. The partial coating has a Ni layer formed of Ni or a Ni alloy formed on the Sn layer, and an Ag layer formed of Ag or an Ag alloy formed on the Ni layer,
At the interface between the Sn layer and the Ni layer, an Sn-Ni layer containing a Sn-Ni solid solution in which Ni is dissolved in Sn and / or an intermetallic compound of Sn and Ni is formed,
An average crystal grain size as viewed from a normal direction to a rolled surface of the base material in the Ni layer is 10 nm or more and 500 nm or less, and a coefficient of variation of the average crystal grain size is 1 or less. Conductive member.
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| JP2015086446A (en) * | 2013-10-31 | 2015-05-07 | 三菱伸銅株式会社 | Conductive member for connector |
| JP2016065316A (en) * | 2013-06-10 | 2016-04-28 | オリエンタル鍍金株式会社 | Plated laminate |
| JP2016166396A (en) * | 2015-03-10 | 2016-09-15 | 三菱マテリアル株式会社 | Copper terminal material with silver platting and terminal |
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| JP2016065316A (en) * | 2013-06-10 | 2016-04-28 | オリエンタル鍍金株式会社 | Plated laminate |
| JP2015086446A (en) * | 2013-10-31 | 2015-05-07 | 三菱伸銅株式会社 | Conductive member for connector |
| JP2016166396A (en) * | 2015-03-10 | 2016-09-15 | 三菱マテリアル株式会社 | Copper terminal material with silver platting and terminal |
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