JP5132467B2 - Copper alloy and Sn-plated copper alloy material for electrical and electronic parts with excellent electrical conductivity and strength - Google Patents

Description

  The present invention relates to a copper alloy having excellent conductivity and strength used as a material for electric / electronic parts.

  Copper alloys are excellent in strength, conductivity, and thermal conductivity, so they are parts for home appliances, semiconductor parts such as lead frames for semiconductor devices, materials for electrical and electronic parts such as printed wiring boards, switch parts, bus bars, terminals -Used in various applications such as mechanical parts such as connectors and industrial equipment.

  In addition to strength, conductivity, and thermal conductivity, various properties are required for the copper alloy used in these various applications depending on the application. For example, a bus bar having a contact structure shown in FIG. 1 is known as a bus bar of an in-vehicle junction box (hereinafter abbreviated as “JB”). In this bus bar 1, a female terminal portion 3 having press contact portions 2a and 2b is known. In order to maintain electrical contact with the male terminals 4 such as relays and fuses, the lower portions 5 of the pressure contact portions 2a and 2b of the female terminal portion 3 where stress is concentrated have characteristics such as strength and stress relaxation characteristics. It is required to be excellent. In particular, the stress relaxation characteristic is an important characteristic for maintaining good electrical contact. Moreover, since the thickness of the bus bar 1 is generally 0.64 to 0.8 mm and is difficult to bend, bending workability that can withstand various kinds of processing is also an important characteristic.

  In addition, due to the recent trend toward lower cost, smaller size, and lighter weight for in-vehicle electrical components, in-vehicle JB busbar materials have higher electrical conductivity in addition to the mechanical properties that have been conventionally requested. Specifically, it is desired to be 60% IACS or more [IACS: International Annealed Copper Standard].

  Furthermore, conventionally, the bus bar is used in a state where Sn plating is applied in order to improve the corrosion resistance. Here, as described above, in order to adapt to the recent demands for miniaturization and weight reduction in JB, the number of types in which a semiconductor is directly mounted on a bus bar is increasing, and not only corrosion resistance but also heat resistance of plating after heating, etc. The characteristics of are also becoming important.

  Therefore, various copper alloys have been proposed to cope with these problems. For example, in Patent Document 1, Fe: 0.15 to 0.7% in mass%, P: 0 as a copper alloy suitable for current-carrying parts such as bus bars, connector terminals for automobiles, and terminals for electric / electronic parts. 0.04 to 0.5%, Sn: 0.5% or less, Mg: 0.01 to 0.5%, crystal grain size, electrical conductivity, tensile strength, bending workability and press punchability are predetermined. A range of copper alloys is disclosed.

  Further, in Patent Document 2, as a copper alloy used for bus bars, terminals, etc., Fe: 0.01 to 3.0%, P: 0.01 to 0 for the purpose of improving strength, conductivity and bending workability. .3%, Sn: 0.01-5.0%, Mg: 0.1-1.0%, Zn 0.005-3.0%, crystal grain size and its standard deviation are within a predetermined range A copper alloy is disclosed.

Furthermore, Patent Document 3 discloses Fe: 0.02 to 0.50%, P: 0.01 to 0.1%, Sn as a high conductivity copper alloy having excellent strength, migration resistance, and stress relaxation properties. : Copper alloy containing 0.1 to 1.0%, Mg: 0.1 to 1.0%, Zn: 0.3 to 2.0% is disclosed.
JP 2007-291518 A (Claims 1, 2, 6 etc.) JP 2007-177274 A (Claims 1, 4, 5, etc.) Japanese Patent Laid-Open No. 03-97816 (claims, etc.)

  However, the copper alloy disclosed in Patent Document 1 has a problem that Sn plating peels off when heated at 150 ° C. for a long time, and the heat-resistant peelability of Sn plating after heating is inferior. In addition, the copper alloy disclosed in Patent Document 2 needs to be rapidly cooled after the cold-rolled material is rapidly heated to a high temperature, which increases the manufacturing cost. Further, this copper alloy has a problem that the conductivity is not sufficiently high.

  Furthermore, since the copper alloy disclosed in Patent Document 3 has a small amount of P with respect to elements that form P compounds, specifically Fe and Mg, in the precipitation treatment in annealing at 500 ° C. for 2 hours, The amount of Fe and Mg to be dissolved increases and it is difficult to obtain high conductivity. Moreover, it cannot be said that other characteristics are sufficient.

  Accordingly, the object of the present invention is to provide a copper alloy for electric / electronic parts having high conductivity and strength, and excellent stress relaxation characteristics, bending workability, and migration resistance characteristics, and the copper alloy for electric / electronic parts. It is providing the Sn plating copper alloy material excellent in Sn plating heat-resistant peeling property which uses this.

  Therefore, the present inventors diligently studied the Fe and Mg contents necessary for forming Fe—P precipitates and Mg—P precipitates effective for improving the strength and conductivity of the copper alloy. As a result, in the copper alloy, a specific amount of Fe, P, Mg, Sn and Zn is contained, and the balance is composed of Cu and inevitable impurities, and the contents of Fe, Mg and P are , (Fe + Mg) / P is in the range of 2.0 to 4.0, and Fe> Mg, which forms Fe—P precipitates and Mg—P precipitates, and improves strength and conductivity. It was found to be effective for And it discovered that this copper alloy was excellent also in stress relaxation characteristics, bending workability, and migration resistance.

  That is, the copper alloy for electrical / electronic parts of the invention according to claim 1 is Fe: 0.1-0.3% by mass, P: 0.05-0.15% by mass, Mg: 0.04-0. 15% by mass, Sn: 0.01-0.2% by mass and Zn: 0.05-0.5% by mass, with the balance consisting of Cu and inevitable impurities, with respect to the contents of Fe, Mg and P, (Fe + Mg) / P satisfies the relationship of 2.0 to 4.0 and Fe> Mg, the Vickers hardness is 130 or more, and is heated at 150 ° C. for 1000 hours in a direction parallel to and perpendicular to the rolling direction. The subsequent stress relaxation rate is 35% or less, and the Sn plating does not peel after heating at 150 ° C. for 1000 hours.

  By having such a configuration, this copper alloy exhibits high electrical conductivity and strength, and is excellent in stress relaxation characteristics, bending workability, migration resistance characteristics, and Sn plating heat release resistance after heating.

  The Sn-plated copper alloy material of the invention according to claim 2 is a copper alloy base material made of the copper alloy for electric / electronic parts, and a Cu-Sn alloy having a thickness of 3 μm or less formed on the surface of the copper alloy base material. And a Sn plating layer having a thickness of 0.3 to 3.0 μm formed on the surface of the Cu—Sn alloy layer.

  This Sn-plated copper alloy material has high conductivity and strength as well as improved stress relaxation characteristics and bending workability due to such a configuration, and exhibits excellent corrosion resistance due to improved migration resistance, Furthermore, the heat-resistant peelability after heating of the Sn plating layer can be improved. In addition, since there is a Sn layer on the surface, it has excellent solder spreadability when soldering a terminal made of Sn-plated copper alloy material to a substrate using Pb-less solder or general solder, and good solder joint strength Is obtained.

  The Sn-plated copper alloy material of the invention according to claim 3 is a copper alloy base material made of the copper alloy for electric / electronic parts and a Cu—Sn alloy having a thickness of 3 μm or less formed on the surface of the copper alloy base material. A Sn plating layer having a thickness of 0.3 to 2.0 μm formed on the surface of the Cu—Sn alloy layer, and the Cu—Sn alloy layer and the Sn plating layer are made of the copper It is formed by reflowing the Sn plating layer formed on the surface of the alloy base material.

  With this configuration, the Sn-plated copper alloy material has high conductivity and strength, excellent stress relaxation characteristics and bending workability due to the copper alloy constituting the copper alloy base material, and improved migration resistance characteristics. It shows excellent corrosion resistance due to, and further can improve the heat-resistant peelability after heating the Sn layer. In addition, since there is a Sn layer on the surface, it has excellent solder spreadability when soldering a terminal made of Sn-plated copper alloy material to a substrate using Pb-less solder or general solder, and good solder joint strength Is obtained. Furthermore, the reflow treatment after Sn plating reduces the stress generated in the plating layer, does not cause Sn whiskers, and does not cause short circuit even when used for narrow pitch terminals, improving the reliability of electronic components. .

  The copper alloy for electric / electronic parts according to the present invention has high conductivity and strength, and is excellent in stress relaxation characteristics, bending workability, and migration resistance characteristics. Therefore, the copper alloy of the present invention can be effectively used widely not only for materials for electric / electronic parts, but also for home appliances, semiconductor parts, industrial equipment, and automotive electric / electronic parts. In particular, when it is used as a material that constitutes a vehicle-mounted JB bus bar, the bus bar can be reduced in size and weight. Since the copper alloy for electrical / electronic parts according to the present invention can be manufactured by a general copper alloy manufacturing method, it contributes to cost reduction of the bus bar.

  The Sn-plated copper alloy material according to the present invention is a Cu-Sn alloy layer and a Sn-plated layer or Cu-Sn formed on the surface of a copper alloy base material made of the copper alloy according to the present invention. It has an alloy layer and a Sn layer, and has high conductivity and strength as well as excellent stress relaxation characteristics, bending workability and migration resistance characteristics by the copper alloy of the present invention constituting the copper alloy base material. Furthermore, the Sn plating layer or Sn layer formed on the surface is excellent in heat-resistant peelability after heating.

  Hereinafter, the copper alloy for electrical / electronic parts excellent in the electrical conductivity and strength of the present invention (hereinafter referred to as “the copper alloy of the present invention”) and the Sn-plated copper alloy material using the copper alloy of the present invention will be described in detail. .

  The copper alloy of the present invention contains a specific amount of Fe, P, Mg, Sn, and Zn, the remainder has a component composition composed of Cu and inevitable impurities, and the content of Fe, Mg, and P is specified It has the relationship. Hereinafter, the numerical range of the content of each component constituting the copper alloy of the present invention, the reason for limiting the numerical range, and the relationship between the contents of Fe, Mg, and P will be described.

(Fe content: 0.1 to 0.3% by mass)
Fe is an effective element for forming Fe-P-based fine precipitates, improving the strength by precipitation hardening, and improving the conductivity. If the Fe content is less than 0.1% by mass, the effect of improving the strength and conductivity due to sufficient precipitation cannot be obtained, and if it exceeds 0.3% by mass, the conductivity is lowered. Therefore, the Fe content is in the range of 0.1 to 0.3% by mass. The Fe content is preferably 0.12 to 0.28 mass%, more preferably 0.15 to 0.25 mass%.

(P content: 0.05 to 0.15 mass%)
P is an element effective for forming precipitates with Fe and Mg and improving strength by precipitation hardening and improving conductivity. When the P content is less than 0.05 mass%, precipitates with Fe and Mg are not sufficiently formed, and the solid solution amount of Fe and Mg increases, leading to a decrease in conductivity. On the other hand, when the content of P exceeds 0.15% by mass, the solid solution amount of P increases and the conductivity decreases. Therefore, the P content is in the range of 0.05 to 0.15 mass%. The P content is preferably 0.07 to 0.13 mass%, more preferably 0.08 to 0.12 mass%.

(Mg content: 0.04 to 0.15 mass%)
Mg is an effective element for forming Mg-P-based fine precipitates, improving the strength by precipitation hardening, and improving the conductivity. Further, Mg that does not precipitate and remains in solid solution is effective in improving strength and improving stress relaxation resistance due to solid solution. When the Mg content is less than 0.04% by mass, it is possible to sufficiently improve the strength and electrical conductivity due to the precipitation of Mg—P precipitates, the solid solution strengthening by the solid solution Mg, and the improvement of the stress relaxation resistance. If it exceeds 0.15% by mass, the solid solution Mg increases and the electrical conductivity decreases. Therefore, the Mg content is in the range of 0.04 to 0.15 mass%. The content of Mg is preferably 0.06 to 0.13 mass%, more preferably 0.08 to 0.12 mass%.

(Relationship of Fe, Mg and P contents)
In the copper alloy of the present invention, the content of Fe, Mg and P must be such that (Fe + Mg) / P is in a relationship of 2.0 to 4.0. Even if (Fe + Mg) / P is less than 2.0 or more than 4.0, Fe—P precipitates and Mg—P precipitates are not sufficiently precipitated, and the solid solution amount of Fe, Mg and P increases, and the electrical conductivity is increased. Decreases. At this time, since the effect of raising the recrystallization temperature is higher in Fe than Mg, the relationship between Fe and Mg content is Fe> Mg. The range of (Fe + Mg) / P is preferably in the range of 2.5 to 3.5.

(Sn content: 0.01 to 0.2% by mass)
Sn is an element effective for improving the strength by solid solution and improving the stress relaxation resistance. If the Sn content is less than 0.01% by mass, sufficient improvement in strength and stress relaxation resistance due to solid solution cannot be obtained, and if it exceeds 0.2% by mass, the electrical conductivity decreases. Therefore, the Sn content is in the range of 0.01 to 0.2% by mass. The content of Sn is preferably 0.02 to 0.18% by mass, more preferably 0.04 to 0.15% by mass.

(Zn content: 0.05 to 0.5 mass%)
Zn is an element effective for improving the heat-resistant peelability of Sn plating and solder used for joining electronic components and suppressing thermal peeling. If the Zn content is less than 0.05% by mass, a sufficient effect cannot be obtained for improving the Sn plating and the heat-resistant peelability of the solder, and if it exceeds 0.5% by mass, the electrical conductivity decreases. Therefore, the Zn content is in the range of 0.05 to 0.5 mass%. The Zn content is preferably 0.07 to 0.40 mass%, more preferably 0.10 to 0.30 mass%.

(Inevitable impurities)
Inevitable impurities are, for example, Mn, Ni, Co, Zr and the like. The content of these inevitable impurities does not affect the conductivity of the copper alloy of the present invention and does not adversely affect the strength as long as the conductivity is within a range that can satisfy 60% IACS.

  The copper alloy of the present invention is formed into various forms and shapes depending on the application. For example, the sheet material made of the copper alloy of the present invention, a strip formed by slitting the plate member in the width direction, a form obtained by coiling the strip, and various forms and shapes such as a wire rod are formed. And when using the base material (copper alloy base material) which consists of the board | plate material which consists of the copper alloy of this invention, a strip, etc. as a raw material of components for electrical / electronic components, Cu-Sn alloy is formed on the surface of the copper alloy base material. It is preferable to use a Sn-plated copper alloy material in which a layer and a Sn plating layer are formed.

  The Cu—Sn alloy layer is a layer formed by alloying Cu and Sn at the interface between the copper alloy base material and the Sn plating layer by forming the Sn plating layer on the surface of the copper alloy base material. Since Sn has a large diffusion coefficient in Cu even at a moderate temperature, it is generated even when the Sn plating material is left at room temperature. This Cu—Sn alloy layer is brittle and is set to 3 μm or less in order to reduce the bending workability of the Sn plating material. The thickness of the Cu—Sn alloy layer is desirably 2 μm or less.

  The Sn plating layer is formed on the surface of the copper alloy base material for the purpose of improving solderability, corrosion resistance, and the like, and as a result, formed on the surface of the copper alloy base material. It will be formed on the Cu-Sn alloy layer. The thickness of the Sn plating layer is preferably 0.3 to 3.0 μm. When the thickness of the Sn plating layer is less than 0.3 μm, the solder spreadability at the time of soldering is lowered, and the solder joint strength is lowered.

  It is preferable to perform a reflow process on the Sn-plated copper alloy material in which the Sn plating layer is formed on the surface of the copper alloy base material. Thereby, the Sn plating copper alloy material by which the Cu-Sn alloy layer and the Sn layer which the Sn plating layer fuse | melted was formed on the surface of the copper alloy base material is obtained.

  In the Sn-plated copper alloy material after the reflow treatment, the Cu—Sn alloy layer preferably has a thickness of 3.0 μm or less in order to reduce bending workability.

  Further, the Sn layer preferably has a thickness of 0.3 to 2.0 μm in order to ensure solderability.

  The copper alloy of the present invention is not particularly limited as long as it is a method capable of producing a copper alloy satisfying the relationship between the component composition and the contents of Fe, Mg, and P, and is produced according to any method. But you can. Usually, it can manufacture by the method of performing each process of casting, hot rolling, cold rolling, annealing, finish rolling, and low temperature annealing in this order.

Casting can be performed by casting a copper alloy melt prepared by preparing Cu, Fe, P, Mg, Sn, and Zn in the above-described component composition.
The hot rolling is performed by soaking the ingot obtained by casting at 850 to 950 ° C. for 30 minutes to 3 hours, rolling to a predetermined thickness, and further quenching at 700 ° C. or higher. be able to. In this hot rolling, if the rolling temperature is too low, recrystallization may be incomplete and a non-uniform structure may be formed. If the rolling temperature is too high, the crystal grains become coarse and the bending workability may be reduced. And after hot rolling, it water-cools.

  Next, cold rolling is a step of rolling a hot-rolled rolled sheet at a normal reduction of 70% or more before annealing and finish rolling in the next step. By this cold rolling, the crystal grain size and its variation after the subsequent annealing can be adjusted.

  In order to improve (recover) the strength and conductivity of the copper alloy sheet, annealing is performed by recrystallization and precipitation treatment of P compounds (Fe—P precipitates, Mg—P precipitates) to form fine precipitates. It is this process. This annealing can be performed by heating at 450 to 600 ° C. for 15 minutes to 10 hours.

Finish rolling is a process of rolling to a desired thickness. In this finish rolling, when the copper alloy or Sn-plated copper alloy material of the present invention requires bending workability, it is preferable to set the processing rate to 50% or less.
The low-temperature annealing is performed for the purpose of removing the strain due to finish rolling and increasing the stress relaxation characteristics and the spring limit value. This low-temperature annealing can be usually performed by heat treatment at 300 to 500 ° C. for 5 seconds to 1 minute.

  Moreover, the Sn plating copper alloy material which uses the copper alloy of this invention as a base material (copper alloy base material) can be manufactured by performing Sn plating following the said low temperature annealing. Thereby, the Sn plating copper alloy material which has a Cu alloy base material, the Cu-Sn alloy layer which consists of an alloy of a copper alloy base material, and Sn plating, and a Sn plating layer can be obtained.

When reflow treatment is not performed, it is desirable to perform bright Sn plating, for example, stannous sulfate 40 g / l, sulfuric acid 100 g / l, cresol sulfonic acid 30 g / l, dispersant 20 g / l, brightener In a plating bath containing 10 ml / l of formalin, 5 ml / l of formalin, etc., using a Sn plate as the counter electrode with a bath temperature of 20 ° C. and a current density of 2.5 A / dm ² .

In the case of performing reflow treatment, for example, Sn plating is performed in a plating bath containing 50 g / l stannous sulfate, 80 g / l sulfuric acid, 30 g / l cresolsulfonic acid, 10 g / l brightener, and the like. Then, the bath temperature is 30 ° C., an Sn plate is used as the counter electrode, and the current density is 3 A / dm ² .

  Further, it is preferable that the Sn-plated copper alloy material is subjected to a reflow treatment to have a structure in which the copper alloy base material and the Sn layer are more closely joined via the Cu-Sn alloy layer. The reflow treatment can be usually performed by heating at 240 to 600 ° C. for 3 to 30 seconds after Sn plating.

  The copper alloy of the present invention has the above-described component composition, and is manufactured by the above-described manufacturing method and manufacturing conditions, thereby having a high conductivity of 60% IACS or higher and a high strength of Vickers hardness of 130Hv or higher. Furthermore, stress relaxation characteristics (the stress relaxation rate after heating at 150 ° C. for 1000 hours is 35% or less in both parallel and vertical directions), bending workability, migration resistance characteristics, and Sn plating heat-resistant peeling characteristics (1000 hours at 150 ° C.) It is excellent in that the Sn plating does not peel off even after heating. At this time, the average crystal grain size is about 2 to 10 μm when measured by the cutting method described in JIS H0501.

  Examples of the present invention will be specifically described below in comparison with comparative examples.

(Production conditions of samples according to Examples 1 to 7 and Comparative Examples 1 to 14)
The component composition of each example is shown in Table 1. A copper alloy having the component composition shown in Table 1 was melted and then cast into a book mold to obtain an ingot having a thickness of 45 mm. The ingot was soaked at 900 ° C. for 1 hour, then hot rolled to a thickness of 15 mm, and quenched at 700 ° C. or higher. Next, both sides of the hot-rolled sheet after quenching were polished by about 1 mm in thickness to remove surface oxide scale and scratches. Then, it cold-rolled to thickness 1.07-1.28mm. At this time, the target plate thickness was changed according to the processing rate in the next finish rolling. Next, after recrystallization and precipitation annealing at 500 to 550 ° C. for 2 hours, finish rolling was performed to a thickness of 0.64 mm. And it annealed at 350 degreeC for 20 second low temperature, and obtained the sample (copper alloy board).

(Sample evaluation method)
About each copper alloy plate of Examples 1-8 and Comparative Examples 1-14, according to the following test method, measurement of electrical conductivity, Vickers hardness, mechanical properties (0.2% proof stress), stress relaxation rate, and crystal grain size The bending workability was evaluated.

[Measurement of conductivity]
The volume resistivity was measured by a four-terminal method using a double bridge in accordance with a nonferrous metal material conductivity measurement method defined in JIS-H0505. The measured volume resistivity was divided by the volume resistivity 1.7241 × 10 ⁻⁸ Ωm of Universal Annealed Copper Standard and expressed as a percentage to obtain the conductivity (% IACS).

[Measurement of Vickers hardness]
Based on the microhardness test method specified in JIS-Z2248, the Vickers hardness was measured at a test load of 2.94 N (= 0.3 kgf).

[Measuring mechanical properties]
A JIS No. 5 tensile test piece in which the longitudinal direction is the rolling direction (LD: Longitudinal Direction) and the vertical direction (TD: Transverse Direction) was produced by machining. Each of the two test pieces (LD, TD) was subjected to a tensile test according to JIS-Z2241. The tensile strength corresponding to the permanent elongation of 0.2% was determined as the proof stress.

[Measurement of stress relaxation rate]
The stress relaxation rate was measured by the cantilever method. That is, a strip-shaped test piece having a width of 10 mm (in which the length direction is parallel to the rolling direction of the plate (LD): a direction that is parallel to the rolling direction and the direction that is perpendicular to the direction of the direction (TD: Transverse Direction) ) And fix one end to a rigid test bench. When a 10 mm deflection is applied to the test piece at a fixed distance from the fixed end, the surface stress corresponding to 80% of the 0.2% proof stress of the material in each direction at the fixed end is aligned with the sampling direction of the test piece. To load. The distance from the fixed end of the position where the deflection is given was calculated by a stress relaxation test method by bending of JCBA T309: 2004 copper and copper alloy sheet. The test piece fixed to the rigid body test stand and subjected to deflection was taken out after being held in an oven at 150 ° C. for 1000 hours, and the permanent strain δ when the deflection amount d was removed was measured, and the stress relaxation rate RS = (δ / d) Calculate x100.

[Evaluation of bending workability]
The bending workability was evaluated according to the W-bending test method defined in JBMA-T307, a standard for copper elongation. That is, a test piece having a width of 10 mm and a length of 30 mm was cut out from a copper alloy plate, and Good Way (bending axis was perpendicular to the rolling direction, hereinafter referred to as “GW”) and Bad Way (bending axis was parallel to the rolling direction). , Hereinafter referred to as “BW”). The presence or absence of cracks in the bent portion was visually observed with a 100 × optical microscope and evaluated according to the following criteria.
A No wrinkle B Small wrinkle C Medium to large wrinkle D Small crack E Large crack

(Measurement of crystal grain size)
After polishing the sample surface, etching was performed, and a structure photograph was taken with an optical microscope, and the crystal grain size was measured from the structure photograph by a cutting method defined in JIS H0501 (the direction of the line segment is the plate width direction). In addition to the plate width direction, the measurement was also performed at a right angle and 45 degrees with respect to the plate width direction.

(Production and evaluation of Sn-plated copper alloy sheet)
Sn plating was carried out on the copper alloy plates of Examples 1 and 3 and Comparative Examples 9, 12, 13 and 14 under the following plating conditions to form a 1.0 μm thick Sn plating layer on the surface.
[Glossy Sn plating conditions]
Composition of plating bath: stannous sulfate 40 g / l, sulfuric acid 100 g / l, cresol sulfonic acid 30 g / l, dispersant 20 g / l, brightener 10 ml / l, formalin 5 ml / l
Plating bath temperature: 20 ° C
Current density: 2.5 A / dm ²
Counter electrode material: Sn plate [Sn plating condition before reflow]
Composition of plating bath: stannous sulfate 50 g / l, sulfuric acid 80 g / l, cresol sulfonic acid 30 g / l, brightener 10 g / l
Plating bath temperature: 30 ° C
Current density: 3A / dm ²
Counter electrode material: Sn plate

  About the copper alloy plate in which the Sn plating layer was formed, according to the following method, the thickness of the Sn layer (shown as “Sn layer thickness” in Table 2) and the thickness of the Cu—Sn alloy layer (see “Cu—Sn in Table 2”). Measurement of “Alloy Layer Thickness”) and Sn plating heat-resistant peel test after heating were performed.

[Measurement of Sn Layer Thickness and Cu-Sn Alloy Layer Thickness]
It measured using the fluorescent X-ray film thickness meter (Seiko Electronics Co., Ltd .: SFT3200).

[Evaluation of heat resistance of Sn plating after heating]
A test piece cut to a size of 30 mm in length and 10 mm in width was heated in an oven at 150 ° C. for 1000 hours, and then subjected to a 180 ° bend-back test with a mandrel 180 ° bending jig at a diameter of 2 mm, and the inside of the bent portion The appearance of the Sn plating was observed for the presence or absence of peeling.

  Next, the reflow process was performed by heating the copper alloy plate in which the Sn plating layer before reflow was formed at 380 degreeC for 13 second (s). Thus, for the copper alloy sheet on which the Sn layer was formed, according to the above-described method, the thickness of the Sn layer (referred to as “Sn layer thickness” in Table 3) and the thickness of the Cu—Sn alloy layer (referred to as “Cu in Table 3”). -Sn alloy layer thickness "), and Sn plating heat-resistant peel test after heating.

(Test results)
Table 1 shows the measurement results for the above measurements of conductivity, Vickers hardness, mechanical properties (0.2% yield strength), stress relaxation rate, bending workability, and crystal grain size. Moreover, about the copper alloy board in which Sn plating layer was formed, and the copper alloy board which performed the reflow process, the measurement result of Sn layer thickness and the thickness of a Cu-Sn alloy layer, and evaluation of Sn plating heat-resistant peeling property after a heating The results are shown in Table 2 and Table 3.

注：含有量は質量％で示す。
＊１ Ｌ．Ｄ．／Ｔ．Ｄ．を示す。
＊２ １８０℃で２４時間加熱後の応力緩和率（Ｌ．Ｄ．／Ｔ．Ｄ．）
＊３ Ｇ．Ｗ．／Ｂ．Ｗ．についてＲ／ｔの曲げ加工性を評価した。
＊４ ＪＩＳ Ｈ０５０１規定の切断法により測定した。

Note: Content is expressed in mass%.
* 1 L. D. / T. D. Indicates.
* 2 Stress relaxation rate after heating at 180 ° C. for 24 hours (LD / TD)
* 3 G. W. / B. W. The bending workability of R / t was evaluated.
* 4 Measured by the cutting method specified in JIS H0501.

注：含有量は質量％で示す。

Note: Content is expressed in mass%.

  As shown in Table 1, in Comparative Example 1, since the Fe content (0.07% by mass) deviates from the range of the present invention (Fe: 0.1 to 0.3% by mass), the Vickers hardness of the present invention. The result (125) inferior to the range (130 or more) of (Hv) is shown.

  In Comparative Example 2, since the Fe content (0.32% by mass) is out of the range of the present invention (Fe: 0.1 to 0.3% by mass), the conductivity is low (57% IACS). ing.

  In Comparative Example 3, since the P content (0.04% by mass) is out of the range of the present invention (P: 0.05 to 0.15% by mass), the Vickers hardness (Hv) range of the present invention ( The result (125) inferior to 130 or more) is shown.

  In Comparative Example 4, the P content (0.17% by mass) deviates from the range of the present invention (P: 0.05 to 0.15% by mass). D. This shows a large value (37%) of the stress relaxation rate.

  In Comparative Example 5, the Sn content (0.0005% by mass) is out of the range of the present invention (Sn: 0.01 to 0.2% by mass), so the range of the Vickers hardness (Hv) of the present invention. (130 or more) shows inferior results (125), lower yield strength, and T.I. D. Shows a large value (45%) of the stress relaxation rate.

  In Comparative Example 6, since the Sn content (0.22% by mass) is out of the range of the present invention (Sn: 0.01 to 0.2% by mass), the conductivity is low (56% IACS). Show.

  In Comparative Example 7, since the Mg content (0.03% by mass) is outside the range of the present invention (Mg: 0.04 to 0.15% by mass), the range of the Vickers hardness (Hv) of the present invention. The result (128) inferior to (130 or more) is shown.

  In Comparative Example 8, since the Mg content (0.17% by mass) is outside the range of the present invention (Mg: 0.04 to 0.15% by mass), the conductivity is low (55% IACS). Show.

  In Comparative Example 9, since the Zn content (0.03% by mass) is outside the range of the present invention (Zn: 0.05 to 0.5% by mass), as shown in Tables 2 and 3, after heating, The result (exfoliation existence) inferior to Sn plating heat-resistant exfoliation nature of No. 2 is shown.

  In Comparative Example 10, since the Zn content (0.7% by mass) is outside the range of the present invention (Zn: 0.05 to 0.5% by mass), the conductivity is low (56% IACS). Show.

  In Comparative Example 11, the Fe and Mg contents are Fe <Mg, and the relationship of the present invention (Fe> Mg) is not satisfied. Therefore, the Vickers hardness (Hv) is more than the range of the present invention (130 or more). Inferior results (125) are shown.

  In Comparative Example 12, since the Zn content (0 mass%) is out of the range of the present invention (Zn: 0.05 to 0.5 mass%), as shown in Table 2 and Table 3, Sn plating after heating is performed. The result is inferior in heat-resistant peelability (with peeling).

  In Comparative Example 13, the Sn content (0 mass%) and the Zn content (0 mass%) are within the scope of the present invention (Sn: 0.001 to 0.2 mass%, Zn: 0.05 to 0.00%). 5% by mass), T. D. This shows a large value (37%) of the stress relaxation rate.

  In Comparative Example 14, the P content (0.035 mass%), the Sn content (0.3 mass%), and the Mg content (0.2 mass%) are within the scope of the present invention (P: 0). 0.05 to 0.15 mass%, Sn: 0.001 to 0.2 mass%, Mg: 0.04 to 0.15 mass%), and the contents of Fe, Mg, and P Since the relationship ((Fe + Mg) / P: 2.0 to 4.0) is not satisfied, the conductivity is low (51% IACS).

  In contrast to these comparative examples 1 to 14, in Examples 1 to 7, the contents of Fe, P, Sn, Mg and Zn are within the scope of the present invention, and the contents of Fe, Mg and P are Satisfying the relationship of the invention ((Fe + Mg) / P: 2.0 to 4.0, Fe> Mg), Vickers hardness (130 or more), stress relaxation rate in the direction parallel to and perpendicular to the rolling direction It is 35% or less, and shows excellent results (no peeling) for the Sn plating heat-resistant peelability after heating.

It is the schematic which shows the structural example of a bus bar.

Explanation of symbols

1 Bus bar 2a, 2b Pressure contact part 3 Female terminal part 4 Male terminal 5 Lower part

Claims (3)

Fe: 0.1-0.3 mass%, P: 0.05-0.15 mass%, Mg: 0.04-0.15 mass%, Sn: 0.01-0.2 mass%, and Zn: 0.05 to 0.5% by mass, with the balance being Cu and inevitable impurities,
About content of Fe, Mg, and P, (Fe + Mg) / P satisfies the relationship of 2.0 to 4.0 and Fe> Mg, the Vickers hardness is 130 or more, the direction parallel to the rolling direction, and Electrical and electronic parts with excellent electrical conductivity and strength, characterized in that the stress relaxation rate after heating at 150 ° C. for 1000 hours in a right angle direction is 35% or less and Sn plating does not peel after heating at 150 ° C. for 1000 hours Copper alloy. A copper alloy base material comprising the copper alloy for electrical and electronic parts according to claim 1;
A Cu—Sn alloy layer having a thickness of 3 μm or less formed on the surface of the copper alloy base material;
An Sn-plated copper alloy material comprising: a Sn-plated layer having a thickness of 0.3 to 3.0 μm formed on the surface of the Cu-Sn alloy layer. A copper alloy base material comprising the copper alloy for electrical and electronic parts according to claim 1;
A Cu—Sn alloy layer having a thickness of 3 μm or less formed on the surface of the copper alloy base material; and a Sn plating layer having a thickness of 0.3 to 2.0 μm formed on the surface of the Cu—Sn alloy layer; The Cu—Sn alloy layer and the Sn plating layer are formed by reflowing an Sn plating layer formed on the surface of the copper alloy base material. Copper alloy material.

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