JP5986822B2 - Cu-Ni-Si-based copper alloy Sn plated plate and method for producing the same - Google Patents

Description

The present invention relates to a Cu—Ni—Si based copper alloy Sn-plated plate and a method for producing the same, and more particularly to a Cu—Ni—Si after reflow treatment in which heat-resistant peelability and contact electrical resistance are balanced with good values. The present invention relates to a copper alloy Sn plated plate and a method for producing the same.

Copper alloy plates for electronic materials used for conductive materials such as connectors, terminals, relays, and switches are required to have both high strength, high electrical conductivity, and thermal conductivity as basic characteristics of the alloy. In addition to these characteristics, bending workability, stress relaxation resistance, heat resistance, adhesion to plating, solder wettability, etching workability, press punching, corrosion resistance, and the like are also required.
Recently, the use amount of an age-hardening type copper alloy plate is increasing as the copper alloy plate for electronic materials. With age-hardening type copper alloy sheets, by aging the solution-treated supersaturated solid solution, fine precipitates are uniformly dispersed, increasing the strength of the alloy and reducing the amount of solid solution elements in copper. Electrical conductivity is improved. For this reason, a material excellent in mechanical properties such as strength and spring property and having good electrical conductivity and thermal conductivity can be obtained. Among the age-hardening type copper alloy plates, the Cu-Ni-Si based copper alloy plate is a representative copper alloy plate having both high strength and high conductivity, and a fine Ni-Si based intermetallic compound in the copper matrix. The strength and conductivity increase due to the precipitation of particles.
When these Cu-Ni-Si-based copper alloy plates are used for conductive materials, particularly electrical contact materials, an underlayer is included on the surface in order to stably obtain durability, insertion / removability, contact resistance, etc. The Sn plating layer is often applied, but these Sn plating plates have a weak point that the plating layer tends to peel from the copper alloy plate base material when kept at a high temperature for a long time. Various improvements have been made.

Patent Document 1 discloses that the thermal detachment of the plating is improved by limiting the aging condition of the copper alloy using the hardness as an index.
In Patent Document 2, Ni: 0.5 to 4.0%, Si: 0.1 to 1.0%, Mg: 0.01 to 0.1%, S: 0.0015% or less, O: 0.0. 0015% or less, or further 0.005 to 1.0% of one or more of P, B, As, Fe, Co, Cr, Al, Sn, Ti, Zr, In, and Mn as subcomponents In addition, copper alloys for conductive springs are disclosed that are used in terminals, connectors, relays, switches, etc. that have high strength, high conductivity, good stress relaxation properties, plating heat release properties, silver plating properties, and good corrosion cracking resistance. ing.
In Patent Document 3, a base material is a copper-based alloy containing 1.0 to 4.5% by mass of Ni and 0.2 to 1.0% by mass of Si, with the balance being Cu and inevitable impurities. In the Sn plating strip, the S concentration and the C concentration at the interface between the plating layer and the base material are adjusted to 0.050% by mass or less to improve the heat-resistant peelability of Sn plating.
Further, as an improvement in contact resistance, Patent Document 4 has a Sn plating film on the surface, and Zn is present at a concentration of 0.1 to 10% by mass on the outermost surface of the Sn plating film after reflow treatment, And it is the Sn plating strip of copper or a copper alloy having a Zn concentration of 0.01% by mass or less at a depth of 0.1 μm (in terms of SiO ₂ ) or more from the outermost surface, and after plating the copper alloy with Sn, Low contact electricity even under high-temperature conditions or long-term use, suitable for various connectors, especially mating connector terminals, manufactured by surface treatment that contacts a solution containing zinc ions and then reflow treatment Copper or copper alloy Sn plating strips that maintain resistance are disclosed.

JP 63-262448 A JP-A-5-059468 JP 2007-291458 A JP 2008-248332 A

  Conventional Cu-Ni-Si-based copper alloy reflow Sn-plated plates have many excellent properties such as heat-resistant peelability, contact electrical resistance, corrosion resistance, and press workability, and have been demanded recently. Under various conditions of use, there was no Sn-plated plate after the reflow treatment in which plating heat resistance peelability and contact electrical resistance were balanced at a high level.

  The present invention provides a reflow Sn-plated plate of a Cu—Ni—Si based copper alloy in which plating heat resistance peelability and contact electrical resistance are balanced at a high level and a method for producing the same.

In view of these circumstances, as a result of intensive studies, the inventors balance the plating heat resistance peelability and the contact electrical resistance of the Cu-Ni-Si based copper alloy Sn plated plate after the reflow treatment with a good value. The ratio between the P concentration present in the surface Sn phase of the plating film layer and the P concentration present in the copper alloy base material has a great influence on the improvement of the plating heat release property. The ratio between the Zn concentration present in the interface layer of Zn and the Zn concentration present in the copper alloy base material greatly affects the improvement of the contact electrical resistance, and these P concentration ratio and Zn concentration ratio are within the optimum ranges. It was found that the purpose is achieved by adjusting.
In addition, in order to produce a Cu-Ni-Si-based copper alloy Sn plated plate after this reflow treatment, an Sn plating solution having an optimum composition and properties is used, and heat treatment is carried out under optimum reflow conditions, thereby It has also been found that the optimum P concentration ratio and Zn concentration ratio are realized, and the plating heat release resistance and the contact electrical resistance are balanced with good values.

That is, the present invention relates to 1.0 to 4.0 mass% Ni, 0.2 to 0.9 mass% Si, 0.3 to 1.5 mass% Zn, 0.001 to 0.2 mass. A copper alloy plate containing% P and the remainder composed of Cu and inevitable impurities is used as a base material, and from the surface to the base material, a surface Sn phase having a thickness of 0.2 μm or less, thickness: 0.2 to 0.8μm of Sn phase, thickness: Sn-Cu alloy phase 0.5～1.4Myuemu, thickness: order consists of the order of 0~0.8μm the Cu phase having a Kki coating layer, the surface Sn The ratio (C / D) of the P concentration (C) of the phase to the P concentration (D) of the base material is 1.1 to 2.0, and the thickness between the plating film layer and the base material: A ratio (A / B) of Zn concentration (A) in the interface layer of 0.8 to 1.4 μm and Zn concentration (B) of the base material is 0.5 to 0.8. .

In the Cu-Ni-Si-based copper alloy Sn-plated plate of the present invention, the base material component is 1.0 to 4.0 mass% Ni, 0.2 to 0.9 mass% Si, 0.3 to 1 .5% by mass of Zn, 0.001 to 0.2% by mass of P, the remainder being composed of Cu and inevitable impurities, after reflow treatment through the interface layer formed on the base material surface The plating film layer is formed.
Cu-Ni-Si based copper alloy is a representative copper alloy having both high strength and high electrical conductivity. Precipitation of fine Ni-Si based intermetallic compound particles in the copper matrix results in strength and electrical conductivity. Rises. Ni and Si in the Cu-Ni-Si-based copper alloy are subjected to an aging treatment, whereby fine particles of an intermetallic compound mainly containing Ni2Si are formed, the strength of the copper alloy is remarkably increased, and the electric conductivity is increased. Also rises.
If Ni is less than 1.0% by mass or Si is less than 0.2% by mass, the desired strength cannot be obtained even if the other component is added. Further, when Ni exceeds 4.5% by mass or Si exceeds 1.0% by mass, sufficient strength can be obtained, but the conductivity becomes low, and coarse Ni that does not contribute to the improvement of strength. -Si-based particles (crystallized substances and precipitates) are generated in the matrix phase, and bending workability, etching properties and the like are lowered.
Zn has the effect of improving strength and heat resistance, and particularly improving the heat resistance of solder joints.
If it is added in the range of 0.3 to 1.5% by mass and below this range, the desired effect cannot be obtained.
In addition, Zn migrates from the base material to the interface layer, Sn—Cu alloy phase, Sn phase, and surface Sn phase during reflow treatment after plating or when used at high temperatures, but Zn concentration migrates to the interface layer. By making the ratio of the Zn concentration remaining in the base metal 0.5 to 0.8, the contact electrical resistance is maintained well.
P has an effect of suppressing a decrease in springiness caused by bending. If it is added in the range of 0.001 to 0.2% by mass and less than 0.001%, the desired effect cannot be obtained, and if it exceeds 0.2%, the heat resistance peelability of the solder is remarkably impaired.
Further, P is less migrated from the base material than Zn, and the ratio between the P concentration of the surface Sn phase mainly resulting from P from the Sn plating solution and the P concentration remaining in the base material. By setting the value to 1.1 to 2.0, the heat-resistant peelability is maintained well.

In the present invention, the plating film layer has a thickness of 0.2 μm or less, a surface Sn phase, a thickness of 0.2 to 0.8 μm, a thickness of 0.5 to 1.4 μm from the surface to the base material. It is comprised in order of Sn-Cu alloy phase and Cu phase of thickness: 0-0.8 micrometer.
Although it is difficult to clearly distinguish the surface Sn phase from the Sn phase existing immediately below, it is a phase having a significantly higher P concentration and a thickness of 0.2 μm or less than the Sn phase. If the thickness exceeds 0.2 μm, the effect of improving plating heat-resistant peelability is saturated and wasted.
When the thickness of the Sn phase is less than 0.2 μm, the solder wettability decreases, and when the thickness exceeds 0.8 μm, the thermal stress generated inside the plating layer when heated is increased.
The Sn—Cu alloy phase is hard, and if the thickness is less than 0.5 μm, the effect of reducing the insertion force during use as a connector is weakened and the strength is reduced. If the thickness exceeds 1.4 μm, The thermal stress generated in the plating film layer is increased, and the plating peeling is promoted, which is not preferable.
When the thickness of the Cu phase exceeds 0.8 μm, the thermal stress generated inside the plating film layer at the time of heating becomes high, and the plating peeling is promoted, which is not preferable.
If the thickness of the interface layer is less than 0.8 μm, peeling may occur between the plating film layer and the base material at the time of heating, and if the thickness exceeds 1.4 μm, the effect of reducing the contact electrical resistance is obtained. Decrease.

When the ratio (C / D) between the P concentration (C) of the surface Sn phase and the P concentration (D) of the base material is less than 1.1, the heat-resistant peelability is lowered, and the ratio (C / D) is 2 If it exceeds 0.0, the effect is saturated and useless.
P present in the surface Sn phase is mainly caused by P contained in the Sn plating solution.
When the ratio (A / B) between the Zn concentration (A) in the interface layer and the Zn concentration (B) in the base material is less than 0.5, the contact electrical resistance decreases, and the ratio (A / B) is reduced. When it exceeds 0.8, the effect is saturated, and the durability during high temperature use tends to be lowered.
P existing in the surface Sn phase is mainly caused by P from the Sn plating solution.
Zn existing in the boundary layer is caused by Zn migrated from the base material to the boundary layer.
The P concentration of the surface Sn phase in the present invention is a peak appearing at a position corresponding to the surface Sn phase in the P concentration profile obtained by GDS (glow discharge emission spectroscopic analyzer) in the depth direction of the copper alloy Sn plated plate. It is the density of the vertex.
In the present invention, the Zn concentration in the interface layer is a peak appearing at a position corresponding to the interface layer in the Zn concentration profile obtained by GDS (glow discharge emission spectroscopic analyzer) in the depth direction of the copper alloy Sn-plated plate. It is the density of the vertex.

Furthermore, in the Cu—Ni—Si based copper alloy Sn plated plate of the present invention, the base material contains 0.2 to 0.8 mass% of Sn.
Sn has an effect of improving strength and heat resistance, and also has an effect of improving stress relaxation resistance. Sn is added in the range of 0.2 to 0.8% by mass. Below this range, the desired effect cannot be obtained, and when it exceeds, the conductivity decreases.

Furthermore, in the Cu—Ni—Si based copper alloy Sn plated plate of the present invention, the base material contains 0.001 to 0.2 mass% of Mg.
Mg has the effect of improving stress relaxation properties and hot workability, but less than 0.001% by mass has no effect, and if it exceeds 0.2% by mass, castability (decrease in casting surface quality), heat The inter-workability and plating heat-resistant peelability are reduced.

Furthermore, in the Cu—Ni—Si based copper alloy Sn plated plate of the present invention, the base material is Fe: 0.007 to 0.25 mass% , Cr: 0.001 to 0.3 mass%, Zr: 0.001-0.3 mass% contains 1 type (s) or 2 or more types, It is characterized by the above-mentioned.
Fe has the effect of improving hot rollability (suppressing the occurrence of surface cracks and ear cracks), refining Ni and Si precipitation compounds, and improving plating heating adhesion, but its content is If the content is less than 0.007%, the desired effect cannot be obtained. On the other hand, if the content exceeds 0.25%, the effect of improving the hot rolling property is saturated and the conductivity is adversely affected. Therefore, the content was determined to be 0.007 to 0.25%.
P has an effect of suppressing a decrease in spring property caused by bending, but if its content is less than 0.001%, a desired effect cannot be obtained, while its content is 0.2%. If exceeding, the solder heat resistance peelability will be significantly impaired, so the content was determined to be 0.001 to 0.2% .
The Cr and Zr, N i and Si the precipitation compound further is miniaturized to improve the strength of the alloy, but has the effect of further strength by precipitation of itself improve, in less than 0.001% content, If the effect of improving the strength of the alloy is not obtained, and if it exceeds 0.3%, a large precipitate of Cr and / or Zr is formed, the plating property is deteriorated, the press punching property is also deteriorated, and the hot workability is further reduced. Is not preferable, and these contents are set to 0.001 to 0.3%, respectively.

Furthermore, the manufacturing method of Cu-Ni-Si-based copper alloy Sn-plated plate of the present invention, the surface of the base material, to form a respective plated layer by plating Cu or a Cu alloy, a Sn or Sn alloy in this order after heating to hit the reflow process, before the SL when forming the plating layer of Sn or a Sn alloy, containing P of 0.01 wt% or less, the surface tension is 40~60mN / m, viscosity of 1. Using an Sn plating solution of 2 to 1.8 mPa · s, the reflow treatment is performed in a medium in which the temperature variation is controlled to ± 2 ° C. or less after each plating layer is heated to 230 ° C. or more. It cools to 20-60 degreeC, It is characterized by the above-mentioned.

As a manufacturing method, first , on the surface of the base material, a plating layer is formed in a predetermined thickness in consideration of the plating thickness after reflow treatment of Cu or Cu alloy plating and the boundary layer thickness, and further on the surface. In consideration of the plating thickness after reflow treatment of Sn or Sn alloy, a plating layer is formed to a predetermined thickness.
In this case, when plating Sn or Sn alloy, Sn plating containing 0.01% by mass or less of P, having a surface tension of 40 to 60 mN / m and a viscosity of 1.2 to 1.8 mPa · s. Use liquid.
In addition, the Sn plating solution preferably contains an appropriate amount of brightener and surfactant, using an antifoaming agent that reduces the foam by half after 2 minutes in the defoaming test in order to maintain the properties and homogeneity of plating. The brightener, antifoaming agent and surfactant also play a role of adjusting the surface tension and viscosity.
Brighteners include hydrophilic polyoxyethylene, polyoxypropylene block polymer, ethylenediamine EO-PO adduct, cumylphenol EO adduct, surfactants include pyrogallol or hydroquinone, and antifoaming agents include hydrophobic polyoxyethylene. Examples thereof include oxyethylene and polyoxypropylene block polymers.
By performing Sn or Sn alloy plating using this Sn plating solution, the ratio (C / D) between the P concentration (C) of the surface Sn phase and the P concentration (D) of the base material is 1 after the reflow treatment. A substrate that is 1 to 2.0 is created. When the condition of the Sn plating solution is out of the above range, the ratio (C / D) does not fall within the predetermined range value.
Next, the plating layer is heated to 230 ° C. or higher, and then subjected to a reflow treatment in which the temperature variation is controlled to be within a range of ± 2 ° C. or lower to 20 to 60 ° C. Thickness: surface Sn phase of 0.2 μm or less, thickness: Sn phase of 0.2 to 0.8 μm, thickness: Sn—Cu alloy phase of 0.5 to 1.4 μm, thickness: 0 to 0.8 μm A plated film layer after reflow treatment constituted in the order of the Cu phase, and an interface layer having a thickness of 0.8 to 1.4 μm are formed between the plated film layer and the base material.
In this reflow process, a surface Sn phase of 0.2 μm or less is formed, and P contained in the Sn plating solution is concentrated in the surface Sn phase and plays a role in improving the heat-resistant peelability. Furthermore, a boundary layer having a thickness of 0.8 to 1.4 μm is formed between the plating film layer and the copper-based alloy plate, and a part of Zn in the base material migrates into the boundary layer. The ratio with respect to the amount of Zn remaining in the base material becomes 0.5 to 0.8, and good contact electric resistance is exhibited.
If the reflow treatment condition is out of the above range, the above-described Cu—Ni—Si based copper alloy Sn plated plate cannot be formed.

The present invention provides a Cu-Ni-Si-based copper alloy Sn-plated plate after reflow treatment in which heat-resistant peelability and contact electrical resistance are balanced with good values.

It is sectional drawing which showed typically the cross section of the Cu-Ni-Si type copper alloy Sn plating board which is one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the Cu—Ni—Si based copper alloy Sn plated plate 1 is composed of 1.0 to 4.0 mass% Ni, 0.2 to 0.9 mass% Si, 0.3 to 1 A surface of a copper alloy plate containing 5% by mass of Zn and 0.001 to 0.2% by mass of P, with the remainder consisting of Cu and inevitable impurities as the base material 2 and having a thickness of 0.2 μm or less Sn phase 5, thickness: 0.2-0.8 μm Sn phase 6, thickness: 0.5-1.4 μm Sn—Cu alloy phase 7, thickness: 0-0.8 μm Cu phase 8 And the ratio (C / D) of the P concentration (C) of the surface Sn phase 5 and the P concentration (D) of the base material 2 is 1.1 to 2.0. The ratio between the Zn concentration (A) in the interface layer 3 having a thickness between the plating film layer 4 and the base material 2 of 0.8 to 1.4 μm and the Zn concentration (B) of the base material 2 (A / B) is 0.5 ~ 0.8.

[Component composition of copper alloy sheet base material]
Cu-Ni-Si based copper alloy is a representative copper alloy having both high strength and high electrical conductivity. Precipitation of fine Ni-Si based intermetallic compound particles in the copper matrix results in strength and electrical conductivity. Rises. Ni and Si in the Cu-Ni-Si-based copper alloy are subjected to an aging treatment, whereby fine particles of an intermetallic compound mainly containing Ni2Si are formed, the strength of the copper alloy is remarkably increased, and the electric conductivity is increased. Also rises.
If Ni is less than 1.0% by mass or Si is less than 0.2% by mass, the desired strength cannot be obtained even if the other component is added. Further, when Ni exceeds 4.5% by mass or Si exceeds 1.0% by mass, sufficient strength can be obtained, but the conductivity becomes low, and coarse Ni that does not contribute to the improvement of strength. -Si-based particles (crystallized substances and precipitates) are generated in the matrix phase, and bending workability, etching properties and the like are lowered.
Zn has the effect of improving strength and heat resistance, and particularly improving the heat resistance of solder joints.
If it is added in the range of 0.3 to 1.5% by mass and below this range, the desired effect cannot be obtained.
In addition, Zn migrates from the base material to the boundary layer, Sn—Cu alloy phase, Sn phase, and surface Sn phase during reflow treatment after plating or when used at a high temperature. By setting the ratio of the Zn concentration remaining in the material to 0.5 to 0.8, the contact electrical resistance is favorably maintained.
P has an effect of suppressing a decrease in springiness caused by bending. If it is added in the range of 0.001 to 0.2% by mass and less than 0.001%, the desired effect cannot be obtained, and if it exceeds 0.2%, the heat resistance peelability of the solder is remarkably impaired.
Further, P is less migrated from the base material than Zn, and the ratio between the P concentration of the surface Sn phase mainly resulting from P from the Sn plating solution and the P concentration remaining in the base material. By setting the value to 1.1 to 2.0, the heat-resistant peelability is maintained well.

Furthermore, it is preferable that the copper alloy plate base material of the Cu—Ni—Si based copper alloy Sn plated plate of the present invention contains 0.2 to 0.8 mass% of Sn.
Sn has an effect of improving strength and heat resistance, and also has an effect of improving stress relaxation resistance. Sn is added in the range of 0.2 to 0.8% by mass. Below this range, the desired effect cannot be obtained, and when it exceeds, the conductivity decreases.
Furthermore, it is preferable that the copper alloy board | substrate base material of the Cu-Ni-Si type copper alloy Sn plating board of this invention contains 0.001-0.2 mass% of Mg.
Mg has the effect of improving stress relaxation properties and hot workability, but less than 0.001% by mass has no effect, and if it exceeds 0.2% by mass, castability (decrease in casting surface quality), heat The inter-workability and plating heat-resistant peelability are reduced.
Furthermore, the copper alloy plate base material of the Cu—Ni—Si based copper alloy Sn plated plate of the present invention is Fe: 0.007 to 0.25 mass%, C: 0.0001 to 0.001 mass%, Cr: It is preferable that 0.001-0.3 mass% and Zr: 0.001-0.3 mass% contain 1 type (s) or 2 or more types.
Fe has the effect of improving hot rollability (suppressing the occurrence of surface cracks and ear cracks), refining Ni and Si precipitation compounds, and improving plating heating adhesion, but its content is If the content is less than 0.007%, the desired effect cannot be obtained. On the other hand, if the content exceeds 0.25%, the effect of improving the hot rolling property is saturated and the conductivity is adversely affected. Therefore, the content was determined to be 0.007 to 0.25%.
P has an effect of suppressing a decrease in spring property caused by bending, but if its content is less than 0.001%, a desired effect cannot be obtained, while its content is 0.2%. If exceeding, the solder heat resistance peelability will be significantly impaired, so the content was determined to be 0.001 to 0.2%.
C has the effect of improving the press punching workability and further improving the strength of the alloy by refining the precipitated compound of Ni and Si, but if the content is less than 0.0001%, the desired effect is obtained. On the other hand, if it exceeds 0.001%, the hot workability is adversely affected, which is not preferable. The content is determined to be 0.0001 to 0.001%.
Cr and Zr have a strong affinity for C and make it easy to contain C in the Cu alloy, and further refine the Ni and Si precipitation compounds to improve the strength of the alloy. If the content is less than 0.001%, the effect of improving the strength of the alloy cannot be obtained. If the content exceeds 0.3%, large precipitates of Cr and / or Zr are formed, and the plating property is increased. However, the press punching processability is also deteriorated, and the hot workability is further deteriorated, which is not preferable. The contents thereof are set to 0.001 to 0.3%, respectively.

[Plating film layer, interface layer, P concentration, Zn concentration]
In the present invention, the plating film layer 4 has a thickness: 0.2 μm or less of the surface Sn phase 5, a thickness: 0.2 to 0.8 μm of the Sn phase 6, and a thickness of 0.5 to 0.5 from the surface to the base material 2. The structure is composed of an Sn—Cu alloy phase 7 of 1.4 μm and a Cu phase 8 of thickness 0 to 0.8 μm.
Although it is difficult to clearly distinguish from the surface Sn phase 5 from the Sn phase 6 existing immediately below, the P concentration is significantly higher than that of the Sn phase 6 and the thickness thereof is 0.2 μm or less. If the thickness exceeds 0.2 μm, the effect of improving plating heat-resistant peelability is saturated and wasted.
When the thickness of the Sn phase 6 is less than 0.2 μm, the solder wettability is lowered. When the thickness exceeds 0.8 μm, the thermal stress generated inside the plating layer when heated is increased.
The Sn—Cu alloy phase 7 is hard, and if the thickness is less than 0.5 μm, the effect of reducing the insertion force when used as a connector is weakened and the strength is reduced. If the thickness exceeds 1.4 μm, The thermal stress generated in the plating film layer 4 is increased, and the plating peeling is promoted, which is not preferable.
When the thickness of the Cu phase 8 exceeds 0.8 μm, the thermal stress generated inside the plating film layer 4 during heating is increased, and plating peeling is promoted, which is not preferable.
If the thickness of the interface layer 3 is less than 0.8 μm, peeling may occur between the plating film layer 4 and the base material 2 during heating. If the thickness exceeds 1.4 μm, the contact electrical resistance is reduced. The effect of doing is reduced.
When the ratio (C / D) of the P concentration (C) of the surface Sn phase 5 and the P concentration (D) of the base material 2 is less than 1.1, the heat-resistant peelability is lowered, and the ratio (C / D) If it exceeds 2.0, the effect is saturated and is useless.
P present in the surface Sn phase 5 is mainly caused by P contained in the Sn plating solution.
When the ratio (A / B) between the Zn concentration (A) in the interface layer 3 and the Zn concentration (B) in the base material 2 is less than 0.5, the contact electrical resistance decreases, and the ratio (A / B) ) Exceeds 0.8, the effect is saturated, and the durability during high temperature use tends to decrease.
The P present in the surface Sn phase 5 is mainly attributable to P from the Sn plating solution.
Zn present in the boundary layer 3 is caused by Zn migrated from the base material 2 to the boundary layer 3.
The P concentration of the surface Sn phase 5 in the present invention is a position corresponding to the surface Sn phase 5 in the P concentration profile obtained by GDS (glow discharge emission spectroscopic analyzer) in the depth direction of the copper alloy Sn plated plate 1. It is the density of the peak vertex that appears in.
In the present invention, the Zn concentration of the interface layer 3 is a position corresponding to the interface layer 3 in the Zn concentration profile obtained by GDS (glow discharge emission spectroscopic analyzer) in the depth direction of the copper alloy Sn plated plate 1. It is the density of the peak vertex that appears in.

[Production method]
As a manufacturing method, first, the component composition is 1.0 to 4.0% by mass of Ni, 0.2 to 0.9% by mass of Si, 0.3 to 1.5% by mass of Zn, 0.001 to Plating thickness after reflow treatment of Cu or Cu alloy plating on the surface of Cu-Ni-Si-based copper alloy base material 1 containing 0.2% by mass of P and the remainder composed of Cu and inevitable impurities, In addition, a plating layer is formed in a predetermined thickness in consideration of the boundary layer thickness, and further, a plating layer is formed in a predetermined thickness on the surface in consideration of the plating thickness after the reflow treatment of Sn or Sn alloy. .
An example of Cu or Cu alloy plating conditions is shown in Table 1, and an example of Sn or Sn alloy plating conditions is shown in Table 2.

In this case, the Cu—Ni—Si based copper alloy is basically produced by melting and casting the material prepared in the component range of the present invention, and the copper alloy ingot is hot-rolled and cold-rolled. Any type can be used as long as it is manufactured in a process including solution treatment, aging treatment, and final cold rolling in this order.
For example, the cooling start temperature after the end of the final hot rolling pass is performed at 350 to 450 ° C., and the cold rolling before the solution treatment is performed at an average rolling rate per pass of 15 to 30% and a total rolling rate of 70. The solution treatment is performed at 800 to 900 ° C. for 60 to 120 seconds, and the aging treatment is performed at 400 to 500 ° C. for 7 to 14 hours.
And in the above-mentioned plating of Sn or Sn alloy, Sn containing 0.01% by mass or less, surface tension of 40 to 60 mN / m, and viscosity of 1.2 to 1.8 mPa · s. Use plating solution. This surface tension and viscosity are important factors that determine the P concentration of the surface Sn phase 5 after the reflow treatment.
In addition, the Sn plating solution preferably contains an appropriate amount of brightener and surfactant, using an antifoaming agent that reduces the foam by half after 2 minutes in the defoaming test in order to maintain the properties and homogeneity of plating. The brightener, antifoaming agent and surfactant also play a role of adjusting the surface tension and viscosity.
Brighteners include hydrophilic polyoxyethylene, polyoxypropylene block polymer, ethylenediamine EO-PO adduct, cumylphenol EO adduct, surfactants include pyrogallol or hydroquinone, and antifoaming agents include hydrophobic polyoxyethylene. Examples thereof include oxyethylene and polyoxypropylene block polymers.
By performing Sn or Sn alloy plating using this Sn plating solution, the ratio (C / D) between the P concentration (C) of the surface Sn phase and the P concentration (D) of the base material is 1 after the reflow treatment. A substrate that is 1 to 2.0 is created. When the condition of the Sn plating solution is out of the above range, the ratio (C / D) does not fall within the predetermined range value.
Next, these plating layers are heated to 230 ° C. or higher, and then subjected to a reflow treatment in which the temperature variation is controlled to ± 2 ° C. or lower to cool to 20 to 60 ° C. Over material 2, thickness: surface Sn phase 5 of 0.2 μm or less, thickness: Sn phase 6 of 0.2 to 0.8 μm, thickness: Sn—Cu alloy phase 7 of 0.5 to 1.4 μm, thickness: 0 The plating film layer 4 after the reflow process constituted in the order of ~ 0.8 μm Cu phase 8, and the boundary surface between the plating film layer 4 and the base material 2: thickness of 0.8 to 1.4 μm Layer 3 is formed.
This reflow treatment includes, for example, a heating step of heating the plating layer to a peak temperature of 240 to 300 ° C. at a heating rate of 20 to 75 ° C./second, and a cooling rate of 30 ° C./second or less after reaching the peak temperature. In the primary cooling step of cooling for 2 to 10 seconds and the secondary cooling step of cooling to 20 to 60 ° C. at a cooling rate of 100 to 250 ° C./second after the primary cooling.
In this case, particularly, if the temperature of the cooling medium is not controlled to be ± 2 ° C. or lower throughout the cooling step after heating, rapid cooling after heating is not stable, and it becomes difficult to obtain the effects of the present invention. The cooling medium is preferably water.
In this reflow process, a surface Sn phase 5 of 0.2 μm or less is formed, and P contained in the Sn plating solution is intensively dispersed in the surface Sn phase 5 to improve the heat-resistant peelability. Furthermore, a boundary layer 3 having a thickness of 0.8 to 1.4 μm is formed between the plating film layer 4 and the base material 2, and a part of Zn in the base material 2 is in the boundary layer 3. The ratio with respect to the amount of Zn remaining in the base material 2 becomes 0.5 to 0.8, and good contact electric resistance is exhibited.
If the reflow treatment condition is out of the above range, the above-described Cu—Ni—Si based copper alloy Sn plated plate cannot be formed.

Materials are prepared so as to have the components shown in Table 3, and cast after melting using a low-frequency melting furnace in a reducing atmosphere to produce a copper alloy ingot having dimensions of 80 mm in thickness, 200 mm in width, and 800 mm in length. did. After heating this copper alloy ingot to 900-980 ° C., as shown in Table 3, hot rolling was performed by changing the cooling start temperature after the end of the final pass of hot rolling, and a hot rolled sheet having a thickness of 11 mm Then, the hot-rolled sheet was water-cooled, and then both faces were cut by 0.5 mm. Next, cold rolling was performed at a rolling rate of 87% to produce a cold-rolled thin plate having a thickness of 1.3 mm, followed by continuous annealing at 710 to 750 ° C. for 7 to 15 seconds, and then pickling. Then, surface polishing was performed, and as shown in Table 3, cold rolling was performed by changing the average rolling rate per pass and the total rolling rate to produce a cold-rolled thin plate having a thickness of 0.3 mm.
As shown in Table 3, the cold-rolled sheet was subjected to a solution treatment by changing the temperature and time, and subsequently, as shown in Table 1, the aging treatment was performed by changing the temperature and time. Cold rolling was performed to prepare copper alloy thin plates of Examples and Comparative Examples.

Samples for plating are cut out from these copper alloy thin plates, and considering the respective plating thicknesses after reflow, Cu plating is performed under the conditions shown in Table 1, followed by Sn plating with P concentration, surface tension, and viscosity shown in Table 4. Sn plating was performed with a liquid (conditions other than P concentration, surface tension, and viscosity were the conditions shown in Table 2). As the surfactant of the Sn plating solution, pyrogallol, as the brightener, ethylenediamine EO-PO adduct, and as the antifoaming agent, hydrophobic polyoxyethylene were used.
Next, reflow treatment was performed in a reflow furnace and a water-cooled bath under the conditions shown in Table 4 for the samples subjected to these Cu plating and Sn plating in order to produce a copper alloy thin plate reflow plating plate.
Samples were cut out from these reflow plating plates, and the thickness of each of the plating film layers composed of the surface Sn phase, Sn phase, Sn-Cu alloy phase, and Cu phase in this order, and the plating film layer and the copper base alloy plate The thickness of the interface layer between the two was measured. These results are shown in Table 4.

Each thickness was measured by observing the cross section of these reflow plated plates by TEM-EDS analysis.
Next, for these samples, the P concentration of the surface Sn phase, the Zn concentration of the interface layer, the P concentration of the copper alloy base material and the Zn concentration were measured, and (P concentration of the surface Sn phase / P of the copper alloy base material). The value of (concentration) and the value of (Zn concentration of interface layer / Zn concentration of copper alloy base material) were obtained. These results are shown in Table 5.
The P concentration and the Zn concentration were determined from a concentration profile in the depth direction by surface analysis using GDS. The measurement conditions for GDS are as follows.
(Measurement condition)
Pretreatment: Immerse in an acetone solvent and perform pretreatment at 38 kHz for 5 minutes using an ultrasonic cleaner.
Equipment: Maribas type glow discharge light emission surface analyzer JY5000RF manufactured by HORIBA, Ltd.
Measurement conditions: RF mode output 35W, Ar gas pressure 600Pa
Module / Phase = 800/400
Anode size 2mm
Flush time 20sec
Background acquis 10 sec
Pre-integration time 30 sec
Surface acquisition60sec
Average time 0.080 sec / pts
Bulk acquisition 10 sec
Next, the heat-resistant peelability and the contact electrical resistance were measured for these samples. These results are shown in Table 5.
For heat-resistant peelability, a strip test piece having a width of 10 mm was collected and heated in the atmosphere at a temperature of 170 ° C. for up to 3000 hours. In the meantime, the sample was taken out from the heating furnace every 100 hours, and 90 ° bending and bending back with a bending radius of 0.5 mm were performed (90 ° bending was reciprocated once). Next, an adhesive tape (# 851 manufactured by 3M) was attached to the surface of the inner periphery of the bend and peeled off. Thereafter, the surface of the inner periphery of the sample was observed with an optical microscope (magnification 50 times), and the presence or absence of plating peeling was examined. And the heating time until plating peeling generate | occur | produced was calculated | required. In Table 5, “> 3000” indicates that no peeling occurred in the test up to 3000 hours.
For contact electrical resistance, contact electrical resistance was measured by a four-terminal method using a contact simulator (trade name CRS-1) manufactured by Yamazaki Seiki Co., Ltd. for a sample heated at 155 ° C. for 400 hours in the air. The measurement conditions are as follows.
Contact load: 50 g.
Current: 200 mA
Sliding speed: 1 mm / min, sliding distance: 1 mm.
In Table 5, ◎ indicates that contact electrical resistance is 10 mΩ or less even after heating at 155 ° C. in an atmospheric atmosphere for 400 hours, ○ indicates less than 10 to 20 mΩ, Δ indicates 20 to 50 mΩ, and × indicates that it exceeds 50 mΩ.

From these results, compared with Comparative Examples 1-9, an Example is excellent in heat-resistant peelability and contact electrical resistance, and heat-resistant peelability and contact electrical resistance are balancing with a favorable value. Recognize.
That is, it can be seen that the Cu-Ni-Si-based copper alloy Sn-plated plate after the reflow treatment produced by the production method of the present invention has a good balance between the heat-resistant peelability and the contact electrical resistance.

  As mentioned above, although the manufacturing method of embodiment of this invention was demonstrated, this invention is not limited to this description, A various change can be added in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Cu-Ni-Si type copper alloy Sn plating board 2 Copper alloy board base material 3 Interface layer 4 Plating film layer 5 Surface Sn phase 6 Sn phase 7 Sn-Cu alloy phase 8 Cu phase

Claims (5)

1.0-4.0 mass% Ni, 0.2-0.9 mass% Si, 0.3-1.5 mass% Zn, 0.001-0.2 mass% P are contained. A copper alloy plate composed of Cu and unavoidable impurities as a base material, and from the surface to the base material, a surface Sn phase with a thickness of 0.2 μm or less, a Sn phase with a thickness of 0.2 to 0.8 μm , thickness: Sn-Cu alloy phase 0.5～1.4Myuemu, thickness: order consists of the order of 0~0.8μm the Cu phase having a Kki coating layer, P concentration of the surface Sn phase (C ) And the P concentration (D) of the base material (C / D) is 1.1 to 2.0, and the thickness between the plating film layer and the base material is 0.8 to 1. Cu—Ni—Si system, characterized in that the ratio (A / B) of Zn concentration (A) in the interface layer of 4 μm to Zn concentration (B) of the base material is 0.5 to 0.8 Copper alloy Gold Sn plated plate.   The said base material contains 0.2-0.8 mass% of Sn, The Cu-Ni-Si type copper alloy Sn plating board of Claim 1 characterized by the above-mentioned. The said base material contains 0.001-0.2 mass% of Mg, The Cu-Ni-Si type copper alloy Sn plating board of Claim 1 or Claim 2 characterized by the above-mentioned. The base material further includes Fe: 0.007 to 0.25% by mass , Cr: 0.001 to 0.3% by mass, Zr: 0.001 to 0.3% by mass , or one or more. It contains, The Cu-Ni-Si type copper alloy Sn plating board of any one of Claims 1-3 characterized by the above-mentioned. It is a method of manufacturing the Cu-Ni-Si type copper alloy Sn plating board as described in any one of Claim 1 to 4 , Comprising: Cu or Cu alloy, Sn or Sn alloy is this on the surface of the said base material. after forming the respective plated layers plated sequentially, per the reflow treatment by heating, prior SL when forming the plating layer of Sn or a Sn alloy, containing 0.01 mass% of P, the surface tension is 40 An Sn plating solution having a viscosity of ˜60 mN / m and a viscosity of 1.2 to 1.8 mPa · s is used, and the reflow treatment has a temperature variation of ±± after heating each of the plating layers to 230 ° C. or higher. C u-Ni-Si-based method for producing a copper alloy Sn-plated plate you characterized by cooling to 20 to 60 ° C. at 2 ℃ in controlled medium below.