JP4397245B2 - Tin-plated copper alloy material for electric and electronic parts and method for producing the same - Google Patents

Description

  The present invention is a tin-plated copper alloy material mainly used for electric / electronic parts such as automobile / consumer terminals, connectors, junction blocks, circuit boards, etc., and particularly used as a fitting type terminal composed of male and female terminals. In particular, the present invention relates to a tin-plated copper alloy material that has a low insertion force at the time of fitting, can maintain excellent electrical reliability even when used at high temperatures, and has excellent corrosion resistance.

A connector used for connecting an electric wire of an automobile or the like uses a fitting type terminal composed of a combination of a male terminal and a female terminal obtained by tin-plating a copper alloy. A connector in which a plurality of fitting type terminals are gathered is called a multipolar terminal connector.
The number of poles of such a connector, that is, the number of terminals in one connector, is increasing as automobiles are becoming more electrical. When the number of terminals increases, the insertion force increases, and a tool is required for mounting, or a large force is required even when a person inserts, which causes a reduction in the efficiency of the assembly work. For this reason, even if the number of poles increases, a terminal with a low insertion force is required so that the insertion force does not become larger than before.

The tin plating terminal has a reduced insertion force by thinning the Sn plating. However, due to the demand for space saving in the automobile interior, the connector installation location has been shifted from the interior to the engine compartment, and the ambient temperature in the engine compartment reaches about 150 ° C. at the maximum. Therefore, when Sn plating is thinned, Cu and alloy elements diffuse from the copper or copper alloy base material, or the base plating such as Ni diffuses to form an oxide on the surface of the Sn plating, thereby increasing the contact resistance of the terminal. Becomes apparent. When the contact resistance increases, there is a concern about malfunction of the electronic control device. Therefore, in reality, it is very difficult to reduce the Sn plating thickness and maintain the electrical reliability.
In addition, when operating or leaving for a long time in an industrial area where sulfurous acid gas is generated as exhaust gas, the surface plating layer corrodes due to the sulfurous acid gas, and further, the corrosion reaches the copper alloy base material, which is reliable as a mating type terminal. Sex is lost.

The following patent documents 1 to 3 describe conventional tin-plated copper alloy materials. Patent Documents 4 to 9 listed below describe conventional copper alloy materials for terminals and connectors containing nickel, tin, and zinc.
Patent Document 1 describes a tin-plated copper alloy material in which a Ni plating layer, an Sn and Cu intermetallic compound layer, and an Sn plating layer are sequentially formed on a Cu-Ni-Zn-based white material. This tin-plated copper alloy material is used for lead frames, and its characteristics for fitting type terminals have not been studied.
In Patent Document 2, a copper barrier layer (thickness 0.2 to 2.5 μm) containing nickel of 25 to 40% on a copper or copper alloy base material, and a Sn or Sn alloy coating layer thereon. A tin-plated copper alloy material is described. This is for a mating type terminal, but the insertion force of the connector has not been studied at all.
Patent Document 3 describes a tin-plated copper alloy material for terminals having a thin Sn plating thickness and a low insertion force.

JP-A-6-196349 JP 2001-526734 A JP 10-46363 A JP-A 61-127842 JP-A-3-226536 JP 2000-80427 A Japanese Patent Laid-Open No. 3-10035 JP-A-11-335756 JP 10-46363 A

By the way, with regard to electrical reliability and corrosion resistance after being left at high temperature, the usage environment has become severe year by year, and it is difficult to maintain the characteristics of the copper alloy alone, and tin-plated copper alloy materials have been put to practical use. When electrical reliability in a high temperature environment of ° C. is required and at the same time a low insertion force is required, it is difficult to cope with conventional tin-plated copper alloy materials.
Therefore, the present inventors have proposed a tin-plated copper alloy material in which a surface plating layer composed of a Ni layer, a Cu—Sn alloy layer and a Sn layer is formed from the copper alloy base material side (Japanese Patent Application No. 2002-219155). This tin-plated copper alloy material can maintain electrical reliability even after a long time in a high-temperature atmosphere, and at the same time satisfies characteristics such as low insertion force and sulfurous acid gas corrosion resistance.

However, characteristics such as electrical reliability, low insertion force, and corrosion resistance of the tin-plated terminal are not determined solely by the surface coating layer, but the material of the copper alloy base material is also important. For example, if the electrical conductivity is high, the heat generation of the terminal can be suppressed, and the present inventors have found that the base material hardness affects the surface hardness and insertion force of the tin-plated copper alloy material, The degree of void generation (causing peeling of the plating layer) at the interface between the copper alloy base material and the surface plating layer varies depending on the material of the copper alloy base material.
Therefore, the present invention finds an optimal copper alloy base material for a surface plating layer comprising a Ni layer, a Cu—Sn alloy layer, and a Sn layer, has high electrical reliability after being left at high temperature, excellent corrosion resistance, and left at high temperature. An object of the present invention is to obtain a tin-plated copper alloy material for electric / electronic parts which has no subsequent peeling of the plating layer and has excellent characteristics particularly for a fitting type terminal having a low insertion force.

  The tin-plated copper alloy material for electric / electronic parts according to the present invention includes Ni: 0.01 to 9%, Sn: 0.01 to 5%, Zn: 0.001 to 15%, and P: One or both of 0.0001 to 0.05% and Si: 0.0001 to 1%, the balance being Cu and impurities, the Ni layer on the surface of the copper alloy base material having a conductivity of 20% or more IACS And a surface plating layer composed of a Cu—Sn alloy layer is formed in this order, or a surface plating layer composed of a Ni layer, a Cu—Sn alloy layer, and a Sn layer is formed in this order. A Cu plating layer may be formed between the copper alloy base material and the Ni layer.

The copper alloy base material further includes Mn, Cr, Mg, Be, Al, Ca, Ti, V, Fe, Co, Zr, Nb, Mo, Ag, In, Pb, Hf, Ta, B, S, C, One or more of Se, Te, and Sb may be included in a total amount of 3% or less. Moreover, when the mass of Ni (when the copper alloy base material further includes Fe or / and Ti, the total mass of Ni, Fe and Ti) is a, and the total mass of P and Si is b, the mass of both It is desirable that the ratio a / b is 3.5 or more. When the copper alloy base material contains neither P nor Si, the above relationship is naturally satisfied.
In the surface plating layer, the Ni layer has a thickness of 0.1 to 1.0 μm, the Cu—Sn alloy layer has a thickness of 0.1 to 1.0 μm, the Sn layer has a thickness of 3.0 μm or less, and Ni The thickness of the Cu layer as the base of the layer is preferably 0.1 to 1.0 μm.

The tin-plated copper alloy material is formed with a surface plating layer composed of a Ni plating layer, a Cu plating layer and a Sn plating layer in this order on the surface of the copper alloy base material having the above composition, and then at 100 to 600 ° C. for 10 minutes or less. The Cu—Sn alloy layer is formed by performing the heat treatment, and the surface plating layer can be manufactured by forming a Ni plating layer and a Cu—Sn alloy layer, or a surface plating layer made of a Sn layer. Here, the Cu plating layer includes a Cu alloy, and the Sn plating layer includes a Sn alloy. Specifically, Cu-1 to 50% Sn as the copper alloy of the Cu plating layer, Sn-1 to 10% Cu, Sn-1 to 10% Ag, Sn-1 to 10% Bi as the Sn alloy of the Sn plating layer Each alloy can be mentioned. In addition, the Sn plating layer made of such an Sn alloy is currently put into practical use from the viewpoint of preventing whisker generation. The alloy element contained in this Cu alloy or Sn alloy is also contained in the Cu—Sn alloy layer formed after the heat treatment. In this manufacturing method, a Cu plating layer is formed as a base of the Ni plating layer as necessary. This Cu plating layer also contains a Cu alloy, and specifically Cu-1 to 10% Zn can be mentioned.
In order to obtain the Cu layer, Ni layer, Cu—Sn alloy layer and Sn layer having the above thickness in the surface plating layer after the heat treatment, the thickness of the Ni plating layer is 0.1 to 1.0 μm before the heat treatment, What is necessary is just to form the thickness of Cu plating layer in the range of 0.05-0.5 micrometer, and the thickness of Sn plating layer in the range of 0.05-3.5 micrometer. On the other hand, instead of alloying the Cu plating layer and the Sn plating layer to form the Cu—Sn alloy layer, direct Cu—Sn alloy plating can also be performed. In this case, alloying by heat treatment is unnecessary.

According to the present invention, it is possible to maintain the bonding reliability (prevention of plating peeling) and electrical reliability (low contact resistance) at the interface between the copper alloy material and the coating layer in a high-temperature atmosphere, and it has excellent corrosion resistance. A tin-plated copper alloy material for parts can be obtained. Since this tin-plated copper alloy material has a high hardness of the copper alloy base material and can obtain a surface hardness of Hv90 or higher (load 25 g), the insertion force is low, and the strength of the copper alloy base material is 550 N / mm ² or higher. Since it is high and has excellent bending workability, it is particularly excellent for fitting type terminals that require low insertion force. For example, when it is used for a small terminal having a terminal width of 1 mm or less or a box-type terminal with severe workability, the insertion force is low, and excellent electrical reliability can be maintained even when used at a high temperature. In addition, the copper alloy base material according to the present invention is excellent in stress relaxation characteristics, spring properties, and the like, and also contains Ni and Sn as well as the surface plating layer, and is excellent in recyclability.

Conventional hot Sn plating (Hot Air Leveled Tin, Hot Dip) has a thickness of 5 to 10 μm and good corrosion resistance, but has a high insertion force. On the other hand, if the Sn plating layer is made thin in order to reduce the insertion force, there is a problem that the corrosion resistance after leaving at high temperature is lowered. Therefore, in order to make the Sn plating layer thin and at the same time secure corrosion resistance, it was considered to form a Ni plating layer on the underlayer. However, if Sn plating is directly performed on the Ni plating layer, an alloy layer of Sn and Ni when left at high temperature There has been a problem that the contact resistance becomes high.
This problem was solved by forming a Cu plating layer between the Ni plating layer and the Sn plating layer. The Cu plating layer and the Sn plating layer are alloyed by heating to form a Cu—Sn alloy layer. By forming this surface plating layer on the surface of the copper alloy base material, a tin-plated copper alloy material having excellent corrosion resistance and low insertion force can be obtained even after being left at a high temperature.
Hereinafter, the surface plating layer according to the present invention will be described.

In the present invention, the Ni layer is formed on the surface of the copper alloy base material in order to prevent the copper alloy base material component from diffusing to the surface. If this Ni layer thickness is less than 0.1 μm, diffusion of the base material component occurs due to defects in the plating layer, and the sulfurous acid gas corrosion resistance after standing at high temperature decreases. On the other hand, when the thickness exceeds 1.0 μm, molding processability is deteriorated and it becomes difficult to mold a small terminal. Therefore, the Ni layer has a thickness of 0.1 to 1.0 μm, preferably 0.1 to 0.5 μm.
The Cu—Sn alloy layer formed on the Ni layer is in the η phase and has a role of preventing the Ni component from diffusing to the surface. When the Cu—Sn alloy layer thickness is less than 0.1 μm, the diffusion of Ni from the Ni layer cannot be suppressed. On the other hand, when it exceeds 1.0 μm, the moldability is lowered and the contact resistance after being left at high temperature is increased. Therefore, the Cu—Sn alloy layer is desirably 0.1 to 1.0 μm.

In order to keep the contact resistance after being left at a high temperature low, the Cu content of the Cu—Sn alloy layer is desirably 60% or less. In order to obtain this composition ratio, the thicknesses of the Cu plating layer and the Sn plating layer before the heat treatment are adjusted, and the composition ratio is obtained after the heat treatment. Alternatively, a Cu—Sn alloy plating layer having this composition ratio is directly formed. When the Cu content of the Cu-Sn alloy layer is 60% or less, the contact resistance can be kept low even without the Sn layer, but the corrosion resistance improves with the Sn layer (the thicker the layer is formed). In addition, since the contact resistance after being left at high temperature can be kept low, the Sn layer is desirably 0.1 μm or more. On the other hand, when the Sn layer becomes thicker, the insertion force becomes higher. More desirable is 1.0 μm or less.
The Cu layer formed between the copper alloy base material and the Ni layer prevents the alloy components (particularly Zn) in the copper alloy base material from diffusing to the surface plating layer side, thereby preventing deterioration of solderability. Has an effect. If this Cu layer is less than 0.1 μm, diffusion of alloy components in the copper alloy base material cannot be suppressed. On the other hand, when it exceeds 1.0 μm, the moldability is lowered. Therefore, the base Cu layer is preferably 0.1 to 1.0 μm.

On the other hand, when the tin-plated copper alloy material is heated (left at high temperature for a long time), the additive component in the copper alloy base material diffuses into the Ni plating layer and voids are generated at the interface between the copper alloy base material and the Ni plating layer. FIG. 1 conceptually shows the state. A void 3 is formed between the copper alloy base material 1 and the Ni layer 2. Since the generation of voids causes peeling of the surface plating layer, it is desirable to suppress this. The copper alloy base material composition of the present invention is selected as an optimal composition in order to prevent the generation of voids.
Hereinafter, the copper alloy base material according to the present invention will be described.

Si or P added as an oxygen scavenger when casting a copper alloy base material reacts with the Ni layer by heating to form an intermetallic compound such as Ni ₂ Si or NiP, which causes voids. By adding Ni to the copper alloy base material, this Ni supplements Si and P in the base material to become precipitates, which prevent them from diffusing into the Ni layer and suppress the generation of voids. Therefore, the Ni content in the copper alloy base material is preferably 0.01% or more, and more preferably 0.1% or more. On the other hand, if the content exceeds 9%, the electrical conductivity decreases. Therefore, the Ni content is set to 0.01 to 9%. Desirably, it is 0.1 to 5.0%.
In order to obtain high heat resistance reliability (there is no plating peeling due to voids even after standing at high temperature), when the mass of Ni is a and the total mass of Si and P is b, a / b is 3.5. It is desirable to set it above. In order to ensure higher heat resistance reliability, a / b is preferably 4.0 or more. When both Si and P are substantially not included, a / b naturally satisfies this relationship.
Note that Fe and Ti have the same effect as Ni. Accordingly, when the copper alloy base material contains Fe or / and Ti, the total mass of Ni, Fe and Ti is calculated as a. When both Fe and Ti are not included, a is the mass of Ni.

Zn, when added together with Ni, has the effect of suppressing void generation at the interface between the copper alloy base material and the Ni layer. The Zn content in the copper alloy base material has this effect even with a trace amount of 0.001% or more, but is preferably 0.1% or more. On the other hand, if the content exceeds 15%, stress corrosion cracking occurs, the reliability as a terminal decreases, and the electrical conductivity decreases. Therefore, the Zn content is 0.001 to 15%. Desirably, it is 0.1 to 3%.
Sn dissolves in the copper alloy base material, reduces the potential difference between the copper alloy base material and the surface plating layer, improves the corrosion resistance, and has the effect of improving the tensile strength and spring characteristics. Even if the Sn content is as small as 0.01% or more, it is effective, but it is desirable to add 0.05% or more. On the other hand, the conductivity of Sn decreases with the addition amount. Therefore, the Sn content is 0.05 to 5%. Desirably, it is 0.1 to 3%.
The elements Mn to Sb can be contained in the copper alloy as impurities or as additive elements. When these elements are contained in a small amount, it has the effect of improving heat resistance and workability by reducing the crystal grain size of the copper alloy or strengthening the crystal grain boundary. Although it has the effect | action which improves an intensity | strength, since electrical conductivity will fall when content increases, it restrict | limits to 3% or less in total.

In the present invention, the copper alloy base material contains Ni, Sn, and Zn, whereby a high tensile strength of 550 N / mm ² or more and a high hardness of Hv 150 or more are obtained in the copper alloy base material. As the number of electric circuits increases and the electric wiring becomes smaller, a small terminal (for example, a width of 2 mm or less) is required, and high tensile strength and excellent bending workability are required. The base material is suitable for this. Further, since the hardness of the copper alloy base material is high, the tin-plated copper alloy material of the present invention has a high surface hardness and is a material suitable for a low insertion force terminal. In the present invention, surface hardness Hv90 (load 0.098N) or more is achieved, and even if the Sn layer is somewhat thick, the friction coefficient is 0.5 or less, and a low insertion force is obtained.
In a small terminal, the current that flows is limited and heat is generated. Therefore, the conductivity is as high as possible, and 20% IACS or more is desirable. In the copper alloy base material of the present invention, by adjusting the contents of Ni, Sn, and Zn and appropriately depositing Ni and other additive elements as intermetallic compounds, a conductivity of 20% IACS or higher can be easily achieved. . It is also possible to achieve 40% IACS or more by the same method, and in that case, it is possible to increase the standard of current that can be passed through the terminal. It is possible to obtain a hardness of Hv 200 or higher by strengthening by precipitation of Ni or the like and solid solution strengthening action by Sn or Zn.
In the tin-plated copper alloy material of the present invention, a stress relaxation rate of 30% or less after heating at 160 ° C. for 1000 hours is achieved.

  In producing the copper alloy base material according to the present invention, the ingot is hot-rolled at a temperature of 850 ° C. or higher, quenched from a temperature of 650 ° C. or higher after rolling, and rapidly cooled. Next, cold rolling is performed, and precipitation hardening heat treatment is performed at 350 to 600 ° C. In the case of increasing the strength, it is preferable to further perform a cold rolling, a solution heat treatment at 650 ° C. or higher, and a rapid cooling step 1 to 3 times in the middle. Subsequently, cold rolling and distortion removal are performed to obtain a desired copper alloy strip. Finally, in order to improve the spring property, low temperature annealing may be performed. The cooling rate for rapid cooling is preferably 10 ° C./min or more.

When the Cu—Sn alloy layer is formed by a heat treatment in the manufacturing process, the residual stress of the surface plating layer is relaxed and the Sn crystal grain size is increased, thereby suppressing the occurrence of whisker in the Sn layer. When the heat treatment time is increased, the productivity is lowered. Therefore, it is desirable to perform the treatment for 10 minutes or less at a temperature of 100 to 600 ° C., and particularly the reflow treatment for 10 minutes or less. Even when Cu—Sn alloy plating is performed, whisker generation can be suppressed by heat treatment.
As for the surface plating layer, when the Cu plating layer and the Sn plating layer are made of Cu alloy and Sn alloy, respectively, it can be plated from an alloy plating solution, but when the alloy layer thickness is 1.0 μm or less, the alloy It is also possible to obtain a plating layer made of the alloy by plating each constituent element in a layer and alloying it by heat diffusion.

As a copper alloy base material, a plate material having a thickness of 0.3 mm having the composition shown in Table 1 was used, and its tensile strength, electrical conductivity, and hardness were measured. The measured values are shown in Table 2.
The surface of each copper alloy base material was plated with Ni, Cu, Sn, or Cu, Ni, Cu, Sn (No. 4, 10) in this order. Tables 3 to 5 show plating baths and plating conditions for each plating. Then, the heat processing of 250 degreeC x 1 minute or 300 degreeC x 10 second was performed, the Cu-Sn alloy layer was formed, and the tin plating copper alloy material which has the surface plating layer shown in Table 1 was obtained. In addition, a part of Sn plating layer before heat processing and the Cu plating layer under it were alloyed by this heat processing, and the Cu-Sn alloy layer was formed. The thickness of the Cu plating layer before the heat treatment is almost ½ of the thickness of the Cu—Sn alloy layer after the heat treatment, and the thickness of the Sn plating layer consumed for alloying is also the Cu—Sn alloy layer after the heat treatment. The thickness was almost ½.

Using this tin-plated copper alloy material as a test material, the thickness of each layer constituting the surface plating layer was measured, and the friction coefficient, contact resistance after standing at high temperature, corrosion resistance (sulfurous acid resistance), molding processability, and voids The occurrence situation was measured. The results are shown in Table 2.
The method of each measurement test is shown below.
[Tensile Strength] Using a JIS No. 5 test piece, a tensile test was performed according to JISZ2201 and measured.
[Conductivity] In accordance with JISH0505, the electrical resistance was measured using a double bridge.
[Hardness] Measured according to JISZ2244.
[Thickness of Ni layer and Sn layer] The thickness was measured using a fluorescent X-ray film thickness meter (Seiko Electronics Co., Ltd .; model SFT156A).
[Thickness of Cu layer] The cross section of the specimen processed by the microtome method was observed with an SEM and calculated as an average thickness by image analysis processing.
[Thickness of Cu-Sn Alloy Layer] After immersing in a stripping solution containing p-nitrophenol and caustic soda as components for 10 minutes to remove the outermost Sn layer, the thickness was measured using a fluorescent X-ray film thickness meter.

[Void Generation Condition after Leaving at High Temperature] After the test material was heated at 160 ° C. for 120 hours, the cross section of the interface between the coating layer and the copper alloy material was observed by SEM by a microtome method to confirm the void generation condition. The level at which voids were 50% or less of the interface (voids were generated when the interface length was less than half of the interface length) was evaluated as ◯, and the level recognized above 50% was evaluated as x.
[Dynamic Friction Coefficient] The shape of the contact portion of the fitting type terminal is simulated, and as shown in FIG. 2, a plate-shaped male test piece 5 cut out from the test material is fixed to a horizontal base 6 and provided thereon. Place the female test piece 7 hemispherically processed with an inner diameter of 1.5 mm, bring the plating surfaces into contact with each other, apply a load of 2.94 N (weight 8) to the female test piece, hold down the male test piece 5, and load horizontally Using a measuring instrument (Model-2152 manufactured by Aiko Engineering Co., Ltd.), the male test piece 5 was pulled in the horizontal direction at a sliding speed of 80 mm / min, and the maximum frictional force F at that time was measured. The coefficient of friction was determined by the following formula (1). In addition, 9 is a load cell and the arrow is a sliding direction.
Friction coefficient = F / P (1)
A friction coefficient of 0.5 or less was evaluated as excellent, and a coefficient exceeding 0.5 was evaluated as inferior.

[Contact resistance after standing at high temperature] After heating the test material in the atmosphere at 160 ° C for 120 hours, the contact resistance was measured by a four-terminal method under the conditions of an open voltage of 20 mV, a current of 10 mA, and no sliding. A contact resistance of 3 mΩ or less was evaluated as having excellent characteristics.
[Molding workability] The test piece was cut out so that the rolling direction was long, and a W-bending test jig specified in JISH3110 was used, and the test piece was 9.8 × 10 ³ N so as to be perpendicular to the rolling direction. Bending was performed with a load. Then, the cross section was cut out and observed by the microtome method. The level at which cracks that occurred in the bent part after the test did not propagate to the copper alloy base material was evaluated as ◯, and the level at which cracks occurred in the copper alloy base material and cracks occurred was evaluated as x.
[Corrosion resistance after standing at high temperature] After heating the sample material at 160 ° C for 120 hours, a sulfurous acid gas test was conducted under conditions of 25 ppm, 35 ° C, 75% RH, and 96 hours. The cross section of the test material after the test was observed, and the level at which corrosion of the base material was not recognized was evaluated as ◯, and the level at which corrosion was recognized was evaluated as ×.

Tables 1 and 2 show that the composition of the copper alloy base material and the surface plating layer configuration are appropriate . All of Nos. 1 to 7 are excellent in the dynamic friction coefficient, the contact resistance and corrosion resistance after heating, and the moldability, and the generation of voids after heating is suppressed.
On the other hand, no. Nos. 8 to 11 have high contact resistance after heating, and the thickness of the Sn layer exceeds the specified value. No. 17 has a high coefficient of friction and a thick Ni layer. No. 15 and the Cu—Sn alloy layer is thick. No. 16 is inferior in moldability. Moreover, the composition of the copper alloy base material is No. which does not contain Ni and Zn. 12, no Zn. 14, No. with high Si content. No. 13 had many voids.

It is a conceptual diagram of the cross section of the tin plating copper alloy material which the void generate | occur | produced. It is a conceptual diagram which shows the measuring method of a dynamic friction coefficient.

Explanation of symbols

3 Void 5 Male test piece 6 units 7 Female test piece
8 spindles 9 load cells

Claims (10)

Ni: 0.5% or more (mass%, the same shall apply hereinafter), 9% or less , Sn: 0.01 % or more, 5% or less , Zn: 0.001 % or more, 1.0% or less , and the balance Cu A surface plating layer comprising a Ni layer and a Cu—Sn alloy layer is formed in this order on the surface of a copper alloy base material having a conductivity of 20% IACS or more. Plating copper alloy material. 2. The electric / electronic component according to claim 1, wherein a Ni plating layer, a Cu—Sn alloy layer, and a surface plating layer including a Sn layer are formed in this order on the surface of the copper alloy base material. Tin-plated copper alloy material. 2. The tin for electric / electronic parts according to claim 1, wherein the Ni layer has a thickness of 0.1 to 1.0 [mu] m, and the Cu-Sn alloy layer has a thickness of 0.1 to 1.0 [mu] m. Plating copper alloy material. The Ni layer has a thickness of 0.1 to 1.0 µm, the Cu-Sn alloy layer has a thickness of 0.1 to 1.0 µm, and the Sn layer has a thickness of 3.0 µm or less. 2. Tin-plated copper alloy material for electric and electronic parts described in 2. 5. The tin-plated copper alloy for electrical and electronic parts according to claim 1, wherein a Cu layer is formed between the copper alloy base material and the Ni layer as the surface plating layer. Wood. The copper alloy base material further contains one or both of P: 0.0001 to 0.05% and Si: 0.0001 to 1%. The tin-plated copper alloy material for electrical and electronic parts described. The copper alloy base material is further Mn, Cr, Mg, Be, Al, Ca, Ti, V, Fe, Co, Zr, Nb, Mo, Ag, In, Pb, Hf, Ta, B, S, C, The tin-plated copper alloy material for electrical / electronic parts according to any one of claims 1 to 6, comprising 1% or more of Se, Te, and Sb in a total amount of 3% or less. The mass ratio a / b of both is 3.5 or more, where the total mass of Ni, Fe and Ti is a, and the total mass of P and Si is b. A tin-plated copper alloy material for electric and electronic parts as described above. A Ni plating layer, a Cu plating layer, and a Sn plating layer are formed in this order on the surface of a copper alloy base material having the composition described in any one of claims 1 to 6 and having an electrical conductivity of 20% IACS or more. Thereafter, heat treatment is performed at a temperature of 100 to 600 ° C. for 10 minutes or less to alloy the Cu plating layer and the Sn plating layer, and the Ni layer and the Cu—Sn alloy layer are formed in this order on the surface of the copper alloy base material. A method for producing a tin-plated copper alloy material for electric / electronic parts, comprising forming a surface plating layer or a surface plating layer in which a Ni layer, a Cu-Sn alloy layer, and a Sn layer are formed in this order. The method for producing a tin-plated copper alloy material for electric / electronic parts according to claim 9, wherein a Cu plating layer is formed between the surface of the Cu alloy base material and the Ni plating layer.

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