JP5088425B2 - Copper alloy, copper alloy sheet and conductive member for electronic and electrical equipment - Google Patents

Description

  The present invention relates to a copper alloy used as an electronic / electrical conductive component typified by a connector of a semiconductor device and other terminals, and particularly Cu—Zn obtained by adding Sn to brass (Cu—Zn alloy). -It relates to a Sn-based copper alloy for electronic and electrical equipment, a copper alloy thin plate using the same, and a conductive member.

Copper or copper alloys are used as electronic / electrical conductive parts represented by connectors and other terminals of semiconductor devices. Among them, brass (from the viewpoint of strength, workability, cost balance, etc.) Cu-Zn alloys) have been widely used. Also, in the case of terminals such as connectors, the surface of a base material (base plate) made of a Cu—Zn alloy is used with tin (Sn) plating, mainly in order to increase the reliability of contact with the other conductive member. Is increasing.
As described above, in a conductive component such as a connector in which the surface is plated with Sn as a base material using a Cu—Zn alloy, in order to improve the recyclability of the Sn plating material and improve the strength, the Cu— Also for the Zn alloy itself, a Cu—Zn—Sn based alloy with Sn added as an alloy component may be used.

  By the way, as a manufacturing process of electronic / electrical equipment conductive parts represented by semiconductor connectors and other terminals, a copper alloy as a raw material is generally made into a thin plate (strip) having a thickness of about 0.05 to 1.0 mm by rolling. In this case, it is normal to form a predetermined shape by punching, and to bend at least a part of the shape, and in that case, contact the mating conductive member near the bent portion to make electrical connection with the mating conductive member. It is often used so as to maintain the contact state with the counterpart conductive material by the spring property of the bent portion. Such connectors and other terminals are not only excellent in conductivity to suppress resistance heat generation during energization, but also have high strength and are stamped by rolling into thin plates (strips). It is desirable that the rollability and punching workability are excellent. Furthermore, the bending workability is excellent in the case of a connector used to maintain the contact state with the mating conductive material in the vicinity of the bent part due to the bending property as described above and the spring property of the bent part. In addition, it is required that the stress relaxation resistance is excellent so that the contact with the counterpart conductive material in the vicinity of the bent portion can be kept good for a long time (or even in a high temperature atmosphere). That is, in a terminal such as a connector that uses the spring property of the bent part to maintain the contact state with the counterpart conductive material, if the stress relaxation resistance is inferior and the residual stress in the bent part is relieved over time, Alternatively, if the residual stress in the bent portion is relaxed under a high temperature use environment, the contact pressure with the counterpart conductive member cannot be maintained sufficiently, and the problem of poor contact tends to occur at an early stage.

  By the way, as measures for improving the stress relaxation resistance of Cu—Zn—Sn alloys used for terminals such as connectors, proposals such as those shown in Patent Documents 1 to 3 have been conventionally made. . Furthermore, although it is different from the use of terminals such as connectors which are the main use in the present invention, as a Cu—Zn—Sn alloy for lead frames, Patent Document 4 also shows a measure for improving the stress relaxation resistance. ing.

That is, in Patent Document 1, it is said that the stress relaxation resistance can be improved by adding Ni to a Cu—Zn—Sn alloy to produce a Ni—P compound, and addition of Fe is also considered. It has been shown to be effective for improving the stress relaxation resistance. In addition, the proposal of Patent Document 2 describes that strength, elasticity, and heat resistance can be improved by adding Ni and Fe together with P to a Cu—Zn—Sn-based alloy to form a compound. Here, although there is no direct description of the stress relaxation resistance, the above improvement in strength, elasticity, and heat resistance seems to mean an improvement in the stress relaxation resistance.
As shown in the proposals of these Patent Documents 1 and 2, the fact that the addition of Ni, Fe, and P to the Cu—Zn—Sn alloy is effective in improving the stress relaxation resistance is the present inventors. However, in the proposals of Patent Documents 1 and 2, only the individual contents of Ni, Fe, and P are taken into consideration. It has been found by experiments and studies by the present inventors that the relaxation characteristics cannot be improved reliably and sufficiently.

On the other hand, in the proposal of Patent Document 3, it is described that the stress relaxation resistance can be improved by adding Ni to the Cu-Zn-Sn alloy and adjusting the Ni / Sn ratio within a specific range. Further, it is described that the addition of a small amount of Fe is effective in improving the stress relaxation resistance.
Although the adjustment of the Ni / Sn ratio shown in the proposal of Patent Document 3 is certainly effective in improving the stress relaxation resistance, the relationship between the P compound and the stress relaxation resistance is completely touched on. Not. That is, the P compound seems to have a great influence on the stress relaxation resistance as shown in Patent Documents 1 and 2, but the proposal of Patent Document 3 relates to elements such as Fe and Ni that generate the P compound. The relationship between the content and the stress relaxation resistance is not considered at all, and even in the experiments by the present inventors, the stress relaxation resistance can be sufficiently and reliably improved only by following the proposal of Patent Document 3. It has been found that it cannot be planned.

In the proposal of Patent Document 4 for lead frames, Ni and Fe are added to a Cu—Zn—Sn alloy together with P, and at the same time, the atomic ratio of (Fe + Ni) / P is in the range of 0.2 to 3. It is described that the stress relaxation resistance can be improved by preparing a Fe—P based compound, a Ni—P based compound, or a Fe—Ni—P based compound.
However, according to experiments by the present inventors, stress relaxation can be achieved only by adjusting the total amount of Fe, Ni, and P and the atomic ratio of (Fe + Ni) / P as defined in Patent Document 4. It has been found that the characteristics cannot be sufficiently improved. The reason is not clear, but in order to reliably and sufficiently improve the stress relaxation resistance, in addition to adjusting the total amount of Fe, Ni, and P and (Fe + Ni) / P, adjusting the Fe / Ni ratio, It is important to adjust Sn / (Ni + Fe), and the stress relaxation resistance cannot be reliably and sufficiently improved unless the respective content ratios are adjusted in a well-balanced manner. Has been found through research.

  As described above, according to the conventional proposal for improving the stress relaxation resistance as a copper alloy for electronic / electric equipment conductive parts made of Cu—Zn—Sn alloy, the effect of improving the stress relaxation resistance is still reliable and It is not enough and further improvements are desired. That is, like a connector, it has a bent portion rolled into a thin plate (strip) and subjected to bending, and is brought into contact with the mating conductive member in the vicinity of the bent portion, In parts used to maintain the contact state, the residual stress is relaxed over time or in a high-temperature environment, and the contact pressure with the counterpart conductive member cannot be maintained, resulting in inconvenience such as poor contact In order to avoid such a problem, conventionally, the thickness of the material has to be increased, leading to an increase in material cost and an increase in weight. It was the actual situation.

JP-A-5-33087 JP 2006-283060 A Japanese Patent No. 3953357 Japanese Patent No. 3717321

  As described above, the conventional Cu-Zn-Sn alloy used as the base material for the Sn-plated brass strip is subjected to bending processing such as a connector and other various terminals, and the other side conductive material near the bent portion. As a thin plate material (strip material) used to obtain contact with a member, it cannot be said that the stress relaxation resistance is still reliable and sufficiently excellent. Sufficient improvement is strongly desired.

  The present invention was made in the background as described above, and as a copper alloy used as a conductive part of electronic and electrical equipment such as connectors and other terminals, particularly as a Cu-Zn-Sn alloy, A copper alloy that has reliable and sufficiently excellent stress relaxation resistance, can reduce the thickness of component materials, and has excellent properties such as strength, rollability, and conductivity, and the like. It is an object to provide a copper alloy thin plate and a conductive member.

As a result of diligent experimentation and research on the solution to the above problems, the present inventors simultaneously added Ni (nickel) and Fe (iron) to Cu-Zn-Sn alloy in appropriate amounts, In addition to adding an appropriate amount of P (phosphorus) and adjusting the individual content of each of these alloy elements, the ratio between Ni, Fe, P and Sn in the alloy, especially Fe and The ratio of Ni content Fe / Ni, the ratio of the total content of Ni and Fe (Ni + Fe) to the content of P (Ni + Fe) / P, the content of Sn and the total content of Ni and Fe (Ni + Fe ) And Sn / (Ni + Fe) in the respective atomic ratios are adjusted within appropriate ranges, the stress relaxation resistance can be improved reliably and sufficiently, and the strength, rollability, and conductivity can be improved. , It found that characteristics superior copper alloy required for connector or other terminal can be obtained, it was able to complete the present invention.
Furthermore, it has been found that the stress relaxation resistance can be further improved by adding an appropriate amount of Co simultaneously with Ni, Fe and P described above.

That is, the copper alloy for electronic / electrical equipment according to the basic form (first form) of the present invention has Zn of 23 to 36.5% (mass%, the same shall apply hereinafter) and Sn of 0.1 to 0.8%. Ni is 0.05% or more, less than 0.15%, Fe is 0.005% or more, less than 0.10%, P is contained in 0.005-0.05%, and the Fe content and Ni The ratio Fe / Ni to the content is the atomic ratio,
0.05 <Fe / Ni <1.5
And the ratio of the total content of Ni and Fe (Ni + Fe) to the content of P (Ni + Fe) / P is an atomic ratio,
3 <(Ni + Fe) / P <15
Furthermore, the ratio Sn / (Ni + Fe) between the Sn content, the Ni content, and the total content of Fe (Ni + Fe) is an atomic ratio,
0.5 <Sn / (Ni + Fe) <5
And the balance is made of Cu and inevitable impurities.

According to such a basic form of the present invention, in addition to an appropriate amount of Sn, Ni and Fe are simultaneously added together with P in an appropriate amount, and between Sn, Ni, Fe, and P. By appropriately regulating the addition ratio, it is possible to obtain a Cu—Zn—Sn based alloy having a structure in which [Ni, Fe] —P based precipitates precipitated from the parent phase (mainly α-phase) are present, Such Cu—Zn—Sn alloys have excellent and sufficient stress relaxation resistance, and at the same time, various characteristics required for connectors and other terminals such as strength, rollability, and conductivity. That is, simply adjusting the individual contents of Sn, Ni, Fe, and P within a predetermined range can sufficiently improve the stress relaxation resistance depending on the contents of these elements in the actual material. In some cases, other characteristics may be insufficient, but by restricting the relative proportions of the contents of these elements within the ranges defined by the above formulas, The stress relaxation characteristics can be reliably and sufficiently improved, and at the same time, various characteristics required for terminal materials such as connectors can be satisfied.
Here, the [Ni, Fe] -P-based precipitates are Ni—Fe—P ternary precipitates, or Fe—P or Ni—P binary precipitates. This means that it may contain a multi-component precipitate containing elements such as Cu, Zn, Sn as main components, O, S, C, Co, Cr, Mo, etc. as impurities. The [Ni, Fe] -P-based precipitates exist in the form of phosphides or alloys in which phosphorus is dissolved.

Moreover, the copper alloy for electronic / electrical equipment according to the second embodiment of the present invention has Zn of 23 to 36.5%, Sn of 0.1 to 0.8%, Ni of 0.05% or more and 0.15%. Fe, 0.005% or more, less than 0.10%, Co containing 0.005% or more, less than 0.10%, P containing 0.005-0.05%, and the total content of Fe and Co The ratio of the amount and the content of Ni (Fe + Co) / Ni is the atomic ratio,
0.05 <(Fe + Co) / Ni <1.5
And the ratio of the total content of Ni, Fe and Co (Ni + Fe + Co) to the content of P (Ni + Fe + Co) / P is an atomic ratio,
3 <(Ni + Fe + Co) / P <15
Further, the ratio Sn / (Ni + Fe + Co) of the Sn content and the total content of Ni, Fe and Co (Ni + Fe + Co) is an atomic ratio,
0.5 <Sn / (Ni + Fe + Co) <5
The balance is made of Cu and inevitable impurities.

In such a copper alloy for electronic and electrical equipment according to the second embodiment, an appropriate amount of Co is added simultaneously with Ni, Fe, and P as described above, and [Ni, Fe, Co] -P-based precipitates are appropriate. The stress relaxation resistance can be further improved by using the structure existing in the structure.
Here, the [Ni, Fe, Co] -P-based precipitates are Ni—Fe—Co—P quaternary precipitates, or Ni—Fe—P, Ni—Co—P, or Fe—Co—. Ternary precipitates of P, or binary precipitates of Fe—P, Ni—P, or Co—P, and other elements such as Cu, Zn, Sn, and impurities It means what may contain multi-component precipitates containing O, S, C, Cr, Mo and the like. The [Ni, Fe, Co] -P-based precipitates exist in the form of phosphides or alloys in which phosphorus is dissolved.

  Moreover, the copper alloy thin plate for electronic / electrical equipment according to the third aspect of the present invention is made of the rolled material of the copper alloy according to the first or second aspect, and has a thickness in the range of 0.05 to 1.0 mm. Is.

  A rolled sheet thin plate (strip material) having such a thickness can be suitably used for connectors and other terminals.

  Furthermore, the copper alloy thin plate for electronic / electrical equipment according to the fourth aspect of the present invention is obtained by applying Sn plating to the surface of the copper alloy thin sheet according to the third aspect.

  In this case, the base material of the Sn plating is made of a Cu—Zn—Sn alloy containing 0.1 to 0.8% of Sn, so that parts such as used connectors are Sn plated brass. It can be recovered as alloy scrap to ensure good recyclability.

  The conductive member for electronic / electrical equipment according to the fifth embodiment of the present invention is made of the copper alloy thin plate of the third or fourth embodiment, and is electrically contacted with the counterpart conductive member by contacting with the counterpart conductive member. It is a conductive member for obtaining a connection, and is configured so that at least a part of the plate surface is bent, and the contact with the counterpart conductive material is maintained by the spring property of the bent portion. is there.

According to the present invention, in addition to an appropriate amount of Sn, Ni and Fe are added together with an appropriate amount together with P, and the addition ratio among Sn, Ni, Fe, and P is appropriately regulated. Thus, a Cu—Zn—Sn alloy having a structure in which [Ni, Fe] -P precipitates precipitated from the matrix (mainly α phase) can be obtained, and such a Cu—Zn—Sn alloy is obtained. Alloys have reliable and sufficient stress relaxation resistance, and at the same time have excellent properties required for connectors and other terminals, such as strength, rollability, and electrical conductivity. In applications such as a connector that contacts the conductive member on the other side at the bent part, stress relaxation does not occur for a long time even in a high temperature environment, so that a reliable contact state can be maintained for a long time. It is possible to thin the other terminal member.
In addition to Sn, Ni, Fe, and P, an appropriate amount of Co is added in an appropriate ratio to form a Cu—Zn—Sn alloy with a structure in which [Ni, Fe, Co] —P precipitates exist. By doing so, the stress relaxation resistance can be reliably and sufficiently improved.

Inventive Example No. of the embodiment of the present invention. It is a structure | tissue photograph of the site | part containing the precipitate by FE-SEM (field emission scanning electron microscope) observation about the alloy of 2. FIG. It is a graph which shows the EDX (energy dispersive X-ray spectroscopy) analysis result about the deposit in FIG.

Hereinafter, the copper alloy for electronic / electric equipment of the present invention will be described in more detail.
The copper alloy for electronic / electrical equipment of the present invention basically has an alloy element content of 23 to 36.5% for Zn, 0.1 to 0.8% for Sn, and 0 for Ni. 0.05% or more, less than 0.15%, Fe is 0.005% or more, less than 0.10%, P is contained in an amount of 0.005 to 0.05%, and each alloy element is contained between each other. As a quantity ratio, the ratio Fe / Ni between the Fe content and the Ni content is an atomic ratio, and the following formula (1): 0.05 <Fe / Ni <1.5 (1)
And the ratio of the total content of Ni and Fe (Ni + Fe) to the content of P (Ni + Fe) / P is an atomic ratio expressed by the following formula (2) 3 <(Ni + Fe) / P <15 (2)
Further, the ratio Sn / (Ni + Fe) between the Sn content, the Ni content and the total Fe content (Ni + Fe) is an atomic ratio, and the following formula (3): 0.5 <Sn / (Ni + Fe) <5 (3)
And the balance of each alloy element is Cu and inevitable impurities.

In addition to the above Zn, Sn, Ni, Fe, P, Co is further contained 0.005% or more, less than 0.10%, and the content ratio between these alloy elements, The ratio (Fe + Co) / Ni between the total content of Fe and Co and the content of Ni is an atomic ratio, and the following formula (1 ′): 0.05 <(Fe + Co) / Ni <1.5 ( 1 ')
Further, the ratio (Ni + Fe + Co) / P of the total content of Ni, Fe and Co (Ni + Fe + Co) to the content of P is an atomic ratio, and the following (2 ′) formula 3 <(Ni + Fe + Co) / P < 15 ... (2 ')
Further, the ratio Sn / (Ni + Fe + Co) between the Sn content and the total content of Ni, Fe and Co (Ni + Fe + Co) is expressed by the following formula (3 ′): 0.5 <Sn / (Ni + Fe + Co) ) <5 ... (3 ')
And the balance of each alloy element is Cu and inevitable impurities.

  First, the reasons for limiting the component composition of these copper alloys of the present invention and the ratio between them will be described.

Zn 23-36.5%:
Zn is a basic alloy element in the copper alloy (brass) which is the subject of the present invention, and is an element effective in improving the strength and the spring property. Moreover, since Zn is cheaper than Cu, it is effective in reducing the material cost of the copper alloy. If Zn is less than 23%, these effects cannot be obtained sufficiently. On the other hand, if Zn exceeds 36.5%, the stress relaxation resistance is deteriorated. As described later, even if Fe, Ni, and P are added according to the present invention, sufficient stress relaxation resistance can be secured. It becomes difficult, corrosion resistance is lowered, and a large amount of β phase is produced, so that cold rolling property and bending workability are also lowered. Therefore, the Zn content is within the range of 23 to 36.5%. The Zn content is particularly preferably in the range of 24 to 36% even within the above range.

Sn 0.1-0.8%:
Addition of Sn is effective in improving strength, and addition of Sn as a base material brass alloy for electronic and electrical equipment materials used after Sn plating improves the recyclability of brass material with Sn plating Is advantageous. Furthermore, it has been found by the present inventors that Sn, when coexisting with Ni and Fe, contributes to the improvement of stress relaxation resistance. If Sn is less than 0.1%, these effects cannot be obtained sufficiently. On the other hand, if Sn exceeds 0.8%, hot workability and cold rollability are deteriorated. There is a possibility that cracking may occur during rolling, and the electrical conductivity also decreases. Therefore, the amount of Sn added is set in the range of 0.1 to 0.8%. The Sn content is particularly preferably within the range of 0.2 to 0.7% even within the above range.

Ni 0.05% or more and less than 0.15%:
Ni, along with Fe and P, is a characteristic additive element in the present invention. By adding an appropriate amount of Ni to a Cu—Zn—Sn alloy and causing Ni to coexist with Fe and P, [Ni, Fe ] -P-based precipitates can be precipitated from the parent phase (mainly α-phase), and by making Ni coexist with Fe, Co, and P, the [Ni, Fe, Co] -P-based precipitates can be Can be precipitated from the phase (mainly α-phase), and the presence of these [Ni, Fe] -P-based precipitates or [Ni, Fe, Co] -P-based precipitates greatly improves the stress relaxation resistance. Can be made. Here, if the addition amount of Ni is less than 0.05%, the stress relaxation resistance cannot be sufficiently improved. On the other hand, if the added amount of Ni is 0.15% or more, the solid solution Ni is increased, the electrical conductivity is lowered, and the cost is increased due to the increased amount of expensive Ni raw materials used. Therefore, the amount of Ni added is in the range of 0.05% or more and less than 0.15%. It should be noted that the addition amount of Ni is preferably within a range of 0.05% or more and less than 0.10%, even within the above range.

Fe 0.005% or more and less than 0.10%:
Fe, along with Ni and P, is a characteristic additive element in the present invention. By adding an appropriate amount of Fe to a Cu—Zn—Sn alloy and causing Fe to coexist with Ni and P, [Ni, Fe ] -P-based precipitates can be precipitated from the parent phase (mainly α-phase), and by making Fe coexist with Ni, Co, and P, the [Ni, Fe, Co] -P-based precipitates can be precipitated. Can be precipitated from the phase (mainly α-phase), and the presence of these [Ni, Fe] -P-based precipitates or [Ni, Fe, Co] -P-based precipitates greatly improves the stress relaxation resistance. Can be made. Here, if the addition amount of Fe is less than 0.005%, the stress relaxation resistance cannot be sufficiently improved. On the other hand, if the amount of Fe added is 0.10% or more, further improvement in the stress relaxation resistance is not observed, the solid solution Fe increases, the conductivity decreases, and the cold rolling property also decreases. End up. Therefore, the addition amount of Fe is set within a range of 0.005% or more and less than 0.10%. Note that the addition amount of Fe is particularly preferably within the range of 0.005% to 0.08% even within the above range.

Co 0.005% or more and less than 0.10%:
Co is not necessarily an essential additive element, but if a small amount of Co is added together with Ni, Fe, and P, [Ni, Fe, Co] -P-based precipitates are generated, and the stress relaxation resistance is further improved. Can be made. Here, if the amount of Co added is less than 0.005%, a further improvement effect of the stress relaxation resistance due to Co addition cannot be obtained. On the other hand, if the amount of Co added is 0.10% or more, the amount of solid solution Co is large. As a result, the conductivity is lowered, and the cost is increased due to an increase in the amount of expensive Co raw materials used. Therefore, when Co is added, the amount of Co added is within the range of 0.005% or more and less than 0.10%. Note that the amount of Co added is preferably within the range of 0.005% to 0.08%, even within the above range. Of course, even if Co is not actively added, Co of less than 0.005% may be contained as an impurity.

P 0.005-0.05%:
P has a high bondability with Fe, Ni, and Co, and if it contains an appropriate amount of P together with Fe and Ni, a [Ni, Fe] -P-based precipitate can be precipitated. If an appropriate amount of P is contained together with Ni and Co, [Ni, Fe, Co] -P-based precipitates can be precipitated, and the stress relaxation resistance can be improved by the presence of these precipitates. . Here, if the amount of P is less than 0.005%, it becomes difficult to sufficiently precipitate [Ni, Fe] -P-based precipitates or [Ni, Fe, Co] -P-based precipitates, and the stress resistance is sufficiently high. The relaxation characteristics cannot be improved. On the other hand, if the amount of P exceeds 0.05%, the amount of P solid solution increases, and the electrical conductivity is lowered and the rollability is lowered, so that cold rolling cracks are likely to occur. Therefore, the P content is in the range of 0.005 to 0.05%, and the P content is preferably in the range of 0.01% to 0.04% even within the above range.
In addition, P is an element that is inevitably mixed in from the melting raw material of the copper alloy. Therefore, in order to regulate the amount of P as described above, it is desirable to appropriately select the melting raw material.

  The balance of the above elements may be basically Cu and inevitable impurities. Here, inevitable impurities include Mg, Al, Mn, Si, (Co), Cr, Ag, Ca, Sr, Ba, Sc, Y, Hf, V, Nb, Ta, Mo, W, Re, Ru, Os, Se, Te, Rh, Ir, Pd, Pt, Au, Cd, Ga, In, Li, Ge, As, Sb, Ti, Tl, Pb, Bi, S, O, C, Be, N, H, Hg, B, Zr, rare earth and the like can be mentioned, but these inevitable impurities are desirably 0.3% by mass or less in total.

  Furthermore, in the copper alloy for electronic and electrical equipment of the present invention, not only the individual addition amount range of each alloy element is adjusted as described above, but the mutual ratio of the content of each element is an atomic ratio, It is important to regulate so as to satisfy the expressions (1) to (3) or the expressions (1 ′) to (3 ′). Therefore, the reasons for limiting the expressions (1) to (3) and (1 ') to (3') will be described below.

(1) Formula: 0.05 <Fe / Ni <1.5
According to the detailed experiments by the present inventors, the Fe / Ni ratio has a great influence on the stress relaxation resistance, and when the ratio is within a specific range, the stress relaxation resistance is sufficiently improved only for the first time. It turns out to get. That is, not only the Fe and Ni coexist and the contents of Fe and Ni are adjusted as described above, but the ratio Fe / Ni is more than 0.05 and 1.5% in terms of atomic ratio. It was found that the stress relaxation resistance can be sufficiently improved when it is within the range below. Here, when the Fe / Ni ratio is 1.5 or more, the stress relaxation resistance is lowered, and even when the Fe / Ni ratio is less than 0.05, the stress relaxation resistance is lowered. On the other hand, if the Fe / Ni ratio is less than 0.05, the amount of expensive Ni raw material used is relatively large, leading to an increase in cost. Therefore, the Fe / Ni ratio is regulated within the above range. The Fe / Ni ratio is particularly preferably within the range of 0.1 to 1.2 even within the above range.

(2) Formula: 3 <(Ni + Fe) / P <15
When Ni and Fe coexist with P, [Ni, Fe] -P-based precipitates are generated, and the stress relaxation resistance can be improved by dispersing the [Ni, Fe] -P-based precipitates. However, if P is excessively contained with respect to (Ni + Fe), the stress relaxation resistance is decreased due to an increase in the proportion of solid solution P, and excessively (Ni + Fe) is contained with respect to P. If this is the case, the stress relaxation resistance decreases due to an increase in the proportion of Ni and Fe that are dissolved, and therefore the (Ni + Fe) / P ratio is also important for sufficiently improving the stress relaxation resistance. When the (Ni + Fe) / P ratio is 3 or less, the stress relaxation resistance decreases as the proportion of the solid solution P increases, and at the same time, the conductivity decreases due to the solid solution P, and the rollability decreases, resulting in coldness. Rolling cracks are likely to occur, and bending workability is also reduced. On the other hand, if the (Ni + Fe) / P ratio is 15 or more, the conductivity decreases due to an increase in the ratio of Ni and Fe in solid solution. Therefore, the (Ni + Fe) / P ratio is regulated within the above range. The (Ni + Fe) / P ratio is preferably in the range of more than 3 and not more than 10 even in the above range.

(3) Formula: 0.5 <Sn / (Ni + Fe) <5
As described above, if Sn coexists with Ni and Fe, Sn contributes to the improvement of the stress relaxation resistance, but the effect of improving the stress relaxation resistance is that the Sn / (Ni + Fe) ratio is not within a specific range. It is not fully demonstrated. That is, when the Sn / (Ni + Fe) ratio is 0.5 or less, sufficient stress relaxation resistance improvement effect is not exhibited, while when the Sn / (Ni + Fe) ratio exceeds 5, the amount of (Ni + Fe) is relatively small. As a result, the amount of [Ni, Fe] -P-based precipitates is reduced, and the stress relaxation resistance is deteriorated. The Sn / (Ni + Fe) ratio is particularly preferably within the range of 1 to 4.5 even within the above range.

(1 ′) Formula: 0.05 <(Fe + Co) / Ni <1.5
When Co is added, it may be considered that a part of Fe is replaced by Co. Therefore, the formula (1 ′) is basically based on the formula (1). That is, when Co is added in addition to Fe and Ni, the (Fe + Co) / Ni ratio has a large effect on the stress relaxation resistance, and when the ratio is within a specific range, the stress relaxation resistance is not changed for the first time. Ni, Fe and Co can coexist and not only the contents of Fe, Ni and Co are adjusted as described above, but also the total content of Fe and Co and the Ni content. When the ratio of (Fe + Co) / Ni is in the range of more than 0.05 and less than 1.5 in atomic ratio, sufficient stress relaxation resistance can be improved. Here, if the (Fe + Co) / Ni ratio is 1.5 or more, the stress relaxation resistance is lowered, and even if the (Fe + Co) / Ni ratio is less than 0.05, the stress relaxation resistance is lowered. Therefore, the (Fe + Co) / Ni ratio is regulated within the above range. The (Fe + Co) / Ni ratio is particularly preferably within the range of 0.1 to 1.2 even within the above range.

(2 ′) Formula: 3 <(Ni + Fe + Co) / P <15
The formula (2 ′) in the case of adding Co is also in accordance with the formula (2). That is, when Ni, Fe, and Co coexist with P, a [Ni, Fe, Co] -P-based precipitate is generated, and the [Ni, Fe, Co] -P-based precipitate is dispersed to reduce stress resistance. Although the relaxation characteristics can be improved, if P is contained excessively with respect to (Ni + Fe + Co), the stress relaxation resistance is decreased due to an increase in the proportion of solid solution P. (Ni + Fe + Co) / P ratio is also important for sufficient improvement. When the (Ni + Fe + Co) / P ratio is 3 or less, the stress relaxation resistance decreases as the proportion of the solid solution P increases, and at the same time, the conductivity decreases due to the solid solution P, and the rollability decreases, resulting in cold Rolling cracks are likely to occur, and bending workability is also reduced. On the other hand, if the (Ni + Fe + Co) / P ratio is 15 or more, the conductivity decreases due to an increase in the ratio of Ni, Fe, and Co dissolved in the solution. Therefore, the (Ni + Fe + Co) / P ratio is regulated within the above range. The (Ni + Fe + Co) / P ratio is preferably in the range of more than 3 and not more than 10 even in the above range.

(3 ′) Formula: 0.5 <Sn / (Ni + Fe + Co) <5
The formula (3 ′) in the case of adding Co is also in accordance with the formula (3). That is, if Sn coexists with Ni, Fe and Co, Sn contributes to the improvement of the stress relaxation resistance, but the effect of improving the stress relaxation resistance is that the Sn / (Ni + Fe + Co) ratio is not within a specific range. It is not fully demonstrated. Specifically, when the Sn / (Ni + Fe + Co) ratio is 0.5 or less, a sufficient effect of improving the stress relaxation property is not exhibited, whereas when the Sn / (Ni + Fe + Co) ratio exceeds 5, relatively (Ni + Fe + Co) When the amount is reduced, the amount of [Ni, Fe, Co] -P-based precipitates is reduced, and the stress relaxation resistance is deteriorated. The Sn / (Ni + Fe + Co) ratio is particularly preferably within the range of 1 to 4.5 even within the above range.

  As described above, each alloy element is adjusted not only for individual contents but also as a ratio between each element so as to satisfy the expressions (1) to (3) or (1 ′) to (3 ′). In copper alloys for electrical equipment, [Ni, Fe] -P-based precipitates or [Ni, Fe, Co] -P-based precipitates as described above were dispersed and precipitated from the matrix phase (mainly α-phase). It is considered that the stress relaxation resistance is improved by the dispersion precipitation of such precipitates.

  In addition, it is known that the crystal grain size of the material has some influence on the stress relaxation resistance. Generally, the smaller the crystal grain size, the lower the stress relaxation resistance, but the strength and bending workability are improved. To do. In the case of the alloy of the present invention, good stress relaxation resistance can be ensured by appropriate adjustment of the component composition and the ratio of each alloy element, so that the crystal grain size can be reduced to improve the strength and bending workability. it can. Although the specific value of the crystal grain size is not particularly limited, it is desirable that the average crystal grain size be 20 μm or less at the stage after the intermediate heat treatment for recrystallization and precipitation in the manufacturing process described later.

  Next, a preferred example of the method for producing a copper alloy for electronic / electric equipment according to the present invention will be described by taking as an example a case where a thin plate (strip) having a thickness of about 0.05 to 1.0 mm is produced.

  First, a molten copper alloy having the composition described above is melted. Here, it is desirable to use so-called 4NCu having a purity of 99.99% or more, for example, oxygen-free copper as the copper raw material among the melted raw materials, but of course, scrap may be used as the raw material. . In the melting step, an atmospheric furnace may be used, but in order to suppress oxidation of Zn, a vacuum furnace or an atmosphere furnace that is an inert gas atmosphere or a reducing atmosphere may be used.

Next, the copper alloy molten metal whose components are adjusted is cast by an appropriate casting method, for example, a batch casting method such as die casting, a continuous casting method, a semi-continuous casting method, etc., and an ingot (slab-like ingot, etc.) And
Thereafter, a homogenization process is performed to eliminate segregation and make the ingot structure uniform as necessary. The conditions for this homogenization treatment are not particularly limited, but it is usually sufficient to heat at 600 to 950 ° C. for 5 minutes to 24 hours. If the homogenization treatment temperature is less than 600 ° C. or the homogenization treatment time is less than 5 minutes, a sufficient homogenization effect may not be obtained. On the other hand, if the homogenization treatment temperature exceeds 950 ° C., a part of the segregation site is present. There is a risk of dissolution, and the homogenization time exceeding 24 hours only increases the cost. The cooling conditions after the homogenization treatment may be determined as appropriate, but usually water quenching may be performed. After homogenization, chamfering is performed as necessary.

  Next, hot rolling is performed on the ingot to obtain a hot rolled sheet having a thickness of about 0.5 to 50 mm. The conditions for this hot rolling are also not particularly limited, but it is usually preferable that the starting temperature is 600 to 950 ° C., the end temperature is 300 to 850 ° C., and the rolling rate is about 10 to 90%. The ingot heating up to the hot rolling start temperature may be performed in combination with the ingot homogenization process described above. That is, hot rolling may be started in a state of being cooled to the hot rolling start temperature without being cooled to near room temperature after the homogenization treatment.

  After the hot rolling, primary cold rolling (intermediate rolling) is performed to obtain an intermediate plate thickness of about 0.05 to 5 mm. The rolling ratio of the primary cold rolling is not particularly limited, but is usually about 20 to 99%. An intermediate heat treatment is performed after the primary cold rolling. This intermediate heat treatment is an important process for recrystallizing the structure and simultaneously dispersing and depositing [Ni, Fe] -P-based precipitates or [Ni, Fe, Co] -P-based precipitates. The conditions of heating temperature and heating time at which precipitates are generated may be applied. The temperature range in which these precipitates are generated is 300 to 800 ° C. Therefore, the intermediate heat treatment may be performed within this temperature range. Further, the heating time in the temperature range may be a time during which these precipitates are sufficiently generated, that is, usually 1 second to 24 hours. However, since the crystal grain size also has some influence on the stress relaxation resistance as described above, it is desirable to measure the recrystallized grains by the intermediate heat treatment and appropriately select the heating temperature and heating time conditions. In addition, you may repeat said cold rolling and intermediate heat processing in multiple times as needed.

The preferable heating temperature and heating time of the intermediate heat treatment vary depending on the specific heat treatment method, as will be described below.
That is, as a specific method of the intermediate heat treatment, a batch-type heating furnace may be used, or continuous heating may be performed using a continuous annealing line. The preferred heating condition for the intermediate heat treatment is that when using a batch-type heating furnace, it is desirable to heat at a temperature of 300 to 800 ° C. for 5 minutes to 24 hours. It is preferable that the temperature is 300 to 800 ° C. and that the temperature is within the range without holding or for about 1 second to 5 minutes. The atmosphere for the intermediate heat treatment is preferably a non-oxidizing atmosphere (nitrogen gas atmosphere, inert gas atmosphere, or reducing atmosphere).
Although the cooling conditions after the intermediate heat treatment are not particularly limited, the cooling is usually performed at a cooling rate of about 2000 ° C./second to 100 ° C./hour.

  After the intermediate heat treatment, cold rolling (finish cold rolling) is performed again in order to finish the product plate thickness (about 0.05 to 1.0 mm) and at the same time obtain the required strength by work hardening. The rolling rate of this finish cold rolling is usually preferably 5 to 99%. If the finish cold rolling rate is less than 5%, sufficient strength as the final plate may not be obtained. On the other hand, if it exceeds 99%, ear cracks may occur. If strength is not required, finish cold rolling may be omitted.

  After finish cold rolling, low-temperature heat treatment (finish annealing) is performed as strain relief annealing as necessary. This low-temperature heat treatment is desirably performed at a temperature in the range of 50 to 500 ° C. for 1 second to 24 hours. If the temperature of the low-temperature heat treatment is less than 50 ° C. or the time of the low-temperature heat treatment is less than 1 second, there is a possibility that a sufficient strain relief effect may not be obtained, while if the temperature of the low-temperature heat treatment exceeds 500 ° C., recrystallization may occur. Furthermore, if the time for the low-temperature heat treatment exceeds 24 hours, only the cost rises.

  As described above, [Ni, Fe] -P-based precipitates or [Ni, Fe, Co] -P-based precipitates were dispersed and precipitated from the matrix mainly composed of the α phase, and the plate thickness was 0.05 to 1.0 mm. A Cu-Zn-Sn-based alloy thin plate (strip material) can be obtained. Such a thin plate may be used as it is for a conductive part for electronic / electrical equipment as it is, but usually, Sn plating with a film thickness of about 0.1 to 10 μm is applied to one or both sides of the plate surface, Sn As a plated copper alloy strip, it is usually used for conductive parts for electronic and electrical equipment such as connectors and other terminals. The Sn plating method in this case is not particularly limited, but electrolytic plating may be applied according to a conventional method, or depending on circumstances, reflow treatment may be performed after electrolytic plating.

  As described above, it is normal to bend a thin plate when it is actually used for a connector or other terminal. It is generally used in such a manner that it is brought into pressure contact with the conductive member to ensure electrical continuity with the counterpart conductive member, and the copper alloy of the present invention is optimal for use in such a manner. is there.

  Hereinafter, the result of the confirmation experiment conducted to confirm the effect of the present invention will be shown as an example of the present invention together with a comparative example. The following examples are for explaining the effects of the present invention, and it goes without saying that the configurations, processes, and conditions described in the examples do not limit the technical scope of the present invention.

Prepare the raw materials consisting of Cu-35% Zn mother alloy, and a purity of 99.99 mass% or more oxygen-free copper (ASTM B152 C10100), and was charged with this high-purity graphite crucible, electricity in _{N 2} gas atmosphere Melted using a furnace. Various additive elements were added into the molten copper alloy, and Nos. 1 and 2 in Tables 1 and 2 were given as examples of the present invention. 1-No. No. 39 in Table 3 as an alloy having the component composition shown in FIG. 41-No. An alloy melt having the composition shown in 57 was melted and poured into a carbon mold to produce an ingot. The size of the ingot was about 25 mm thick × about 25 mm wide × about 150 mm long. Each ingot was processed under the conditions shown in Tables 4-6. That is, first, as a homogenization treatment for the ingot, water quenching was performed after holding at 850 ° C. for a predetermined time in an Ar gas atmosphere.

Next, re-heating so that the hot rolling start temperature is 850 ° C., performing hot rolling with a rolling rate of about 50%, performing water quenching from the rolling end temperature of 500 to 700 ° C., and after performing surface grinding, A hot-rolled material having a thickness of about 11 mm and a width of about 25 mm was produced.
Then, after performing rolling at a rolling rate of about 80% as primary cold rolling (intermediate rolling in Tables 4 to 6), the average grain size after the intermediate heat treatment is intermediate heat treatment (recrystallization and precipitation treatment). Heat treatment was performed at 550 ° C. so as to be about 10 μm.

  In the stage after the intermediate heat treatment, the average crystal grain size was examined as follows. That is, each sample after the intermediate heat treatment was mirror-polished and etched, taken with an optical microscope so that the intermediate rolling direction was beside the photograph, and observed with a 1000 × field of view (about 300 μm × 200 μm). . Next, according to the JIS H 0501 cutting method, draw a line segment of a predetermined length in the vertical and horizontal directions, count the number of crystal grains to be completely cut, and calculate the average value of the cutting length as the average crystal grain size. did. The average crystal grain sizes at the stage after the intermediate heat treatment examined in this way are shown in Tables 4 to 6.

Thereafter, finish cold rolling was performed at the rolling rates shown in Tables 4 to 6, and strips (thin plates) having a thickness of about 0.25 mm and a width of about 25 mm were produced.
Finally, as finishing strain relief annealing (low-temperature heat treatment), after holding for 1 hour at 200 ° C. in an Ar gas atmosphere, water quenching is performed, surface grinding is performed, and a strip for property evaluation is produced. did.

  These strips for property evaluation were examined for rolling properties, electrical conductivity, mechanical properties (yield strength), stress relaxation resistance properties, and microstructure observation. The test method and measurement method for each evaluation item are as follows, and the results are shown in Tables 7 to 9.

[Rollability evaluation]
As the evaluation of the rollability, the presence or absence of ear cracks during the aforementioned finish cold rolling was observed. The case where no or almost no ear cracks were observed visually, ◎, where small ear cracks of less than 1 mm in length occurred, ◯, where ear cracks of 1 mm or more and less than 3 mm occurred, Δ, length A case where a large ear crack of 3 mm or more occurred and the characteristic evaluation was extremely difficult was evaluated as x. In addition, the length of an ear crack is the length of the ear crack which goes to the width direction center part from the width direction edge part of a rolling material.

(Mechanical properties)
A No. 13B test piece defined in JIS Z 2201 was taken from the strip for characteristic evaluation, and 0.2% proof stress σ _0.2 was measured by an offset method of JIS Z 2241. In addition, the test piece was extract | collected so that the tension direction of a tension test might become parallel with the rolling direction of the strip for characteristic evaluation.

〔conductivity〕
A test piece having a width of 10 mm and a length of 60 mm was taken from the strip for characteristic evaluation, and the electrical resistance was determined by a four-terminal method. Moreover, the dimension of the test piece was measured using the micrometer, and the volume of the test piece was calculated. And electrical conductivity was computed from the measured electrical resistance value and volume. In addition, the test piece was extract | collected so that the longitudinal direction might become parallel with the rolling direction of the strip for characteristic evaluation.

[Stress relaxation resistance]
In the stress relaxation resistance test, stress was applied by a method according to the cantilever screw method of Japan Copper and Brass Association Technical Standard JCBA-T309: 2004, and the residual stress ratio after holding at a temperature of 150 ° C. for a predetermined time was measured. .
As a test method, a test piece (width 10 mm) was taken from each specimen in parallel from the longitudinal direction, and the initial deflection displacement was set to 2 mm so that the maximum surface stress of the test piece was 80% of the proof stress. The length was adjusted. The maximum surface stress is determined by the following equation.
Surface stress (MPa) = 1.5 Etδ ₀ / L _s ²
However,
E: Deflection coefficient (MPa)
t: Sample thickness (t = 0.25 mm)
δ ₀ : Initial deflection displacement (2 mm)
L _s : Span length (mm)
It is.
Residual stress rate is measured from bending wrinkles after holding for 80 hours at a temperature of 150 ° C., and those values are 70% or more, ◎, 60% or more, less than 70% ○, 50% or more, 60% Evaluation was made with Δ less than less than, and × less than 50%. The residual stress rate was calculated using the following formula.
Residual stress rate (%) = (1-δ _t / δ ₀ ) × 100
However,
δ _t : Permanent deflection displacement after holding at 150 ° C. for 80 hours (mm)
δ ₀ : Initial deflection displacement (mm)
It is.

[Observation of precipitates]
For each strip for property evaluation, the structure was observed in order to confirm precipitates. The rolled surface of each sample was mirror-polished and etched, and observed at about 40000 times using a FE-SEM (field emission scanning electron microscope). Moreover, about the component of the deposit, it confirmed using EDX (energy dispersive X-ray spectroscopy).

  About each said evaluation result, it shows in Table 7-9. In addition, as an example of the above-described tissue observation, No. of the present invention example. The FE-SEM observation photograph of 2 samples is shown in FIG. Furthermore, No. of the present invention example. FIG. 2 shows the analysis results of the precipitates in sample No. 2 by EDX (energy dispersive X-ray spectroscopy).

  In FIG. 1, a white oval portion near the center is a precipitate. And from the analysis result (FIG. 2) by EDX about this precipitate in FIG. 1, the precipitate contains Fe and P, that is, a kind of [Ni, Fe] -P-based precipitate already defined. It was confirmed that there was.

  Furthermore, the evaluation results of each sample will be described. In addition, No. 1-No. No. 16 is an example of the present invention based on a Cu-30Zn alloy containing about 30% Zn, No. 16; 17-No. No. 27 is an example of the present invention based on a Cu-25Zn alloy containing about 25% Zn, No. 27. 28-No. No. 39 is an example of the present invention based on a Cu-35Zn alloy containing about 35% Zn. 41, no. 42, no. 44-No. 54, no. 56, no. No. 57 is a comparative example based on a Cu-30Zn alloy containing about 30% Zn, No. 57. No. 42 is a comparative example containing 37.1% Zn, No. 42. 55 is a comparative example based on a Cu-25Zn alloy containing about 25% Zn.

  As shown in Tables 7 and 8, not only is the individual content of each alloy element within the range defined by the present invention, but the ratio between the alloy components is within the range defined by the present invention. Inventive Example No. 1-No. No. 39 has a residual stress ratio of 60% or more and excellent stress relaxation resistance, and also has a conductivity of 21% IACS or more, and can be applied to connectors and other terminal members sufficiently. It was confirmed that almost no ear cracks occurred at the time, or even if they occurred, the length was less than 3 mm, the rolling property was good, and the strength was not inferior to that of the conventional material. .

On the other hand, as shown in Table 9, the comparative example No. No. 41 is a conventional material made of a Cu-30Zn alloy, a comparative example No. 41. No. 42 is a conventional material obtained by adding only Sn to a Cu-30Zn alloy. 1-No. Compared to 16, stress relaxation resistance was inferior.
The comparative example No. In No. 43, since the Zn content was excessive, cracking occurred during cold rolling (finish rolling), and subsequent low-temperature heat treatment could not be performed, and each performance evaluation could not be performed.
Furthermore, No. of the comparative example. In No. 44, the Sn amount was excessive, so that cracking occurred during hot rolling, and the subsequent steps could not be performed, and each performance evaluation could not be performed. On the other hand, no. No. 45 does not contain Sn, so that the present invention example No. 45 based on a Cu-30Zn alloy is used. 1-No. Compared to 16, stress relaxation resistance was inferior.
The comparative example No. No. 46 is an invention example No. 46 based on a Cu-30Zn alloy because the amount of Ni is excessive. 1-No. Compared to 16, stress relaxation resistance was inferior. On the other hand, No. of the comparative example. No. 47 did not add Ni, so that the present invention example No. 47 based on a Cu-30Zn alloy was used. 1-No. Compared to 16, stress relaxation resistance was inferior.
The comparative example No. No. 48 is an invention example No. 48 based on the Cu-30Zn alloy because the Fe amount is excessive and the conductivity is as low as 20% IACS or less. 1-No. Compared to 16, stress relaxation resistance was also inferior. On the other hand, no. No. 49 was obtained by adding no Fe, so that the present invention example No. 49 based on a Cu-30Zn alloy was used. 1-No. Compared to 16, stress relaxation resistance was inferior.
Comparative Example No. In No. 50, since the amount of P was excessive, cracking occurred during cold rolling (finish rolling), so that subsequent low-temperature heat treatment could not be performed, and each performance evaluation could not be performed. On the other hand, No. of the comparative example. No. 51 was obtained by adding no P, so that the present invention example No. 51 based on a Cu-30Zn alloy was used. 1-No. Compared to 16, stress relaxation resistance was inferior.

Comparative Example No. 52-No. In each case 57, the individual content of each alloy element is within the range defined by the present invention, but the content ratio (atomic ratio) between the alloy elements is outside the range defined by the present invention. Is.
First of all, no. In the comparative example of No. 52, the Fe / Ni ratio is lower than the lower limit of the formula (1). 1-No. Compared to 16, stress relaxation resistance was inferior. On the other hand, no. The comparative example of No. 53 has an Fe / Ni ratio higher than the upper limit of the formula (1). 1-No. Compared to 16, stress relaxation resistance was inferior.
No. In the comparative example of No. 54, the (Ni + Fe) / P ratio is lower than the lower limit of the formula (2). 1-No. Compared to 16, stress relaxation resistance was inferior. On the other hand, no. In the comparative example of No. 55, the (Ni + Fe) / P ratio is higher than the upper limit of the formula (2). 17-No. Compared to 27, the stress relaxation resistance was inferior.
Furthermore, no. In the comparative example No. 56, the Sn / (Ni + Fe) ratio is lower than the lower limit of the formula (3). 1-No. Compared to 16, stress relaxation resistance was inferior.
On the other hand, no. In the comparative example No. 57, the Sn / (Ni + Fe) ratio is higher than the upper limit of the expression (3). 1-No. Compared to 16, stress relaxation resistance was inferior.

Claims (5)

Zn is 23 to 36.5% (mass%, the same applies hereinafter), Sn is 0.1 to 0.8%, Ni is 0.05% or more and less than 0.15%, Fe is 0.005% or more, 0 Less than 10%, containing 0.005 to 0.05% of P, and the ratio Fe / Ni between the Fe content and the Ni content is atomic ratio,
0.05 <Fe / Ni <1.5
And the ratio of the total content of Ni and Fe (Ni + Fe) to the content of P (Ni + Fe) / P is an atomic ratio,
3 <(Ni + Fe) / P <15
Further, the ratio Sn / (Ni + Fe) between the content of Sn and the total amount of Ni and Fe (Ni + Fe) is an atomic ratio,
0.5 <Sn / (Ni + Fe) <5
A copper alloy for electronic and electrical equipment, characterized in that the balance is made of Cu and inevitable impurities. Zn is 23 to 36.5%, Sn is 0.1 to 0.8%, Ni is 0.05% or more and less than 0.15%, Fe is 0.005% or more and less than 0.10%, Co is 0.005% or more, less than 0.10%, 0.005 to 0.05% P, and the ratio of the total content of Fe and Co to the content of Ni (Fe + Co) / Ni is an atomic ratio so,
0.05 <(Fe + Co) / Ni <1.5
And the ratio of the total content of Ni, Fe and Co (Ni + Fe + Co) to the content of P (Ni + Fe + Co) / P is an atomic ratio,
3 <(Ni + Fe + Co) / P <15
Further, the ratio Sn / (Ni + Fe + Co) of the Sn content and the total content of Ni, Fe and Co (Ni + Fe + Co) is an atomic ratio,
0.5 <Sn / (Ni + Fe + Co) <5
A copper alloy for electronic and electrical equipment, characterized in that the balance is made of Cu and inevitable impurities.   A copper alloy thin plate for electronic / electrical equipment, comprising the rolled material of the copper alloy according to any one of claims 1 and 2, and having a thickness in a range of 0.05 to 1.0 mm.   The copper alloy thin plate for electronic / electric equipment by which Sn plating is given to the surface of the copper alloy thin plate of Claim 3.   A conductive member made of the copper alloy thin plate according to any one of claims 3 and 4, wherein the conductive member is brought into contact with the counterpart conductive member to obtain electrical connection with the counterpart conductive member. In addition, a conductive member for electronic / electrical equipment configured such that at least a part of the plate surface is bent, and the contact with the counterpart conductive material is maintained by the spring property of the bent portion.