CN107923001A - Electronic electric equipment copper alloy, electronic electric equipment copper alloy thin plate, electronic electric equipment conductive component and terminal - Google Patents

Abstract

The copper alloy for electrical and electronic equipment of the present invention contains more than 2 mass % to 36.5 mass % of Zn, 0.1 mass % to 0.9 mass % of Sn, 0.15 mass % to less than 1.0 mass % of Ni, 0.005 mass % % to 0.1% by mass of P, 0.001 to 0.1% by mass of Fe, and the remainder to be composed of Cu and unavoidable impurities, satisfying 3<(Ni+Fe)/P<30 in terms of atomic ratio , 0.3<Sn/(Ni+Fe)<2.7, 0.002≤[Fe/Ni]<0.6, and, relative to the atomic ratio [Fe/Ni] of the Fe content to the Ni content of the entire alloy, Fe, Ni The atomic ratio [Fe/Ni] P of the content of Fe in the [Ni,Fe]-P system precipitates of P and _P satisfies 5≤[Fe/Ni] _P /[Fe/Ni]≤200.

Description

Copper alloys for electrical and electronic equipment, copper alloy sheets for electrical and electronic equipment, Conductive parts and terminals for gas equipment

technical field

The present invention relates to a Cu-Zn-Sn-based copper for electrical and electronic equipment used as a connector for a semiconductor device, other terminals, a movable conductive piece of an electromagnetic relay, or a conductive member for an electrical and electronic equipment such as a lead frame alloy, a copper alloy sheet for electrical and electronic equipment using the copper alloy for electrical and electronic equipment, and a conductive member and terminal for electrical and electronic equipment.

This application claims priority based on Patent Application No. 2015-150338 for which it applied in Japan on July 30, 2015, and uses the content here.

Background technique

Cu—Zn alloys have conventionally been widely used as the above-mentioned electrically conductive member for electronics and electronics from the viewpoint of strength, workability, cost balance, and the like.

In addition, in the case of terminals such as connectors, tin (Sn) plating may be used on the surface of a base material (raw material plate) made of a Cu-Zn alloy in order to improve the reliability of contact with a conductive member on the other side. In conductive parts such as connectors whose surface is plated with Sn using a Cu-Zn alloy as a base material, Cu-Zn-Sn alloys are sometimes used in order to improve the recyclability of the Sn-plated material and to increase the strength.

Here, for example, conductive parts for electronic and electrical equipment such as connectors are generally made into a predetermined shape by pressing a thin plate (rolled plate) with a thickness of about 0.05 to 3.0 mm, and bending at least a part of it. And manufacture. At this time, it is used in such a manner that it contacts the counterpart conductive member in the vicinity of the bent portion to obtain electrical connection with the counterpart conductive member, and maintains the contact state with the counterpart conductive material by the elasticity of the bent portion.

In the case of a connector or the like that is bent and used so as to maintain a contact state with the counterpart conductive material in the vicinity of the bent portion due to the elasticity of the bent portion, excellent heat resistance and stress relaxation resistance are required.

Therefore, methods for improving the heat resistance and stress relaxation resistance of Cu—Zn—Sn-based alloys have been proposed in, for example, Patent Documents 1 to 4.

Patent Document 1 shows that by adding Ni to a Cu-Zn-Sn-based alloy to form a Ni-P-based compound, the stress relaxation resistance can be improved, and the addition of Fe is also effective for improving the stress relaxation resistance. .

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 alloy to form a compound.

In addition, Patent Document 3 describes that adding Ni to a Cu-Zn-Sn alloy and adjusting the Ni/Sn ratio within a specific range can improve the stress relaxation resistance, and that adding a small amount of Fe is also effective in improving stress relaxation resistance.

Furthermore, Patent Document 4, which targets lead frame materials, describes that by adding Ni and Fe together with P to a Cu-Zn-Sn alloy, the atomic ratio of (Fe+Ni)/P By adjusting it within the range of 0.2 to 3, Fe-P-based compounds, Ni-P-based compounds, and Fe-Ni-P-based compounds are produced, thereby improving stress relaxation resistance.

Patent Document 1: Japanese Patent Laid-Open No. 5-33087

Patent Document 2: Japanese Patent Laid-Open No. 2006-283060

Patent Document 3: Japanese Patent No. 3953357

Patent Document 4: Japanese Patent No. 3717321

However, in order to achieve further miniaturization and weight reduction of electronic and electrical equipment, and in copper alloys for electrical and electronic equipment used in conductive parts for electrical and electronic equipment, further improvements in strength, bending workability, heat resistance, and Stress relaxation properties.

However, in Patent Documents 1 and 2, only the individual contents of Ni, Fe, and P are taken into consideration, and it is not always possible to reliably and sufficiently improve the stress relaxation resistance simply by adjusting such individual contents.

In addition, although patent document 3 discloses adjusting the Ni/Sn ratio, it does not consider the relationship between the P compound and the stress relaxation resistance at all.

Furthermore, in Patent Document 4, only by adjusting the total amount of Fe, Ni, and P and the atomic ratio of (Fe+Ni)/P, heat resistance can be improved, but stress relaxation resistance cannot be sufficiently improved.

As described above, the heat resistance and stress relaxation resistance of Cu—Zn—Sn based alloys cannot be sufficiently improved by conventionally proposed methods. Therefore, in the connector with the above-mentioned structure, as time passes, especially in a high-temperature environment, the residual stress relaxes and the contact pressure with the conductive member on the counterpart side cannot be maintained, so that there is a problem that faults such as poor contact are likely to occur in advance. . In order to avoid such a problem, conventionally, the wall thickness of the material had to be increased, resulting in an increase in material cost and weight. Therefore, further improvements in heat resistance and stress relaxation resistance are desired.

Contents of the invention

The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a copper alloy for electrical and electronic equipment that is reliable and sufficiently excellent in heat resistance and stress relaxation resistance, and excellent in strength, and to use the electrical and electronic equipment. Copper alloy sheets for electrical and electronic equipment using copper alloys, conductive parts and terminals for electrical and electronic equipment.

As a result of repeated in-depth experimental studies, the inventors of the present invention have found the following: by adding appropriate amounts of Ni, P, and Fe to Cu-Zn-Sn alloys, [Ni, Fe]-P precipitates precipitated under heat treatment conditions The Fe/Ni ratio in the alloy and the Fe/Ni ratio of the entire alloy are adjusted in an appropriate range, thereby obtaining a copper alloy with excellent strength and bending workability while reliably and sufficiently improving heat resistance and stress relaxation resistance.

Similarly, it was found that by adding appropriate amounts of Ni, P, Fe, and Co to Cu-Zn-Sn-based alloys, the (Fe+Co) in [Ni, (Co, Fe)]-P-based precipitates By adjusting the /Ni ratio and the (Fe+Co)/Ni ratio of the entire alloy within an appropriate range, it is possible to obtain a copper alloy with excellent strength and bendability while reliably and sufficiently improving heat resistance and stress relaxation resistance. .

The present invention was accomplished based on these findings.

The copper alloy for electronic and electrical equipment according to the present invention is characterized by containing more than 2% by mass and not more than 36.5% by mass of Zn, not less than 0.1% by mass and not more than 0.9% by mass of Sn, and not less than 0.15% by mass and less than 1.0% by mass of Ni, 0.005% by mass to 0.1% by mass of P, 0.001% by mass to 0.1% by mass of Fe, the remainder consisting of Cu and unavoidable impurities, the ratio of the total content of Ni and Fe to the content of P ( Ni+Fe)/P satisfies 3<(Ni+Fe)/P<30 in atomic ratio, and the ratio Sn/(Ni+Fe) of the content of Sn to the total content of Ni and Fe is in atomic ratio, Satisfy 0.3<Sn/(Ni+Fe)<2.7, and the ratio of Fe content to Ni content [Fe/Ni] in terms of atomic ratio satisfies 0.002≤[Fe/Ni]<0.6, and, in the parent phase There are [Ni, Fe]-P system precipitates containing Fe, Ni and P, and the atomic ratio [Fe/Ni] of the Fe content to the Ni content of the alloy as a whole, the [Ni, Fe]-P system The atomic ratio [Fe/Ni] _P of the content of Fe in the precipitate to the content of Ni satisfies 5≤[Fe/Ni] _P /[Fe/Ni]≤200.

According to the copper alloy for electronic and electrical equipment of the above-mentioned constitution, Ni and Fe are added together with P and the mutual addition ratio of Sn, Ni, Fe and P is limited, and the copper alloy containing Ni, Fe, and P precipitated from the parent phase (α-phase main body) [Ni, Fe]-P precipitates of P. Wherein, relative to the atomic ratio [Fe/Ni] of the content of Fe to the content of Ni in the alloy as a whole, the atomic ratio [Fe/Ni] of the content of Fe in the [Ni,Fe]-P system precipitate to the content of Ni [Fe/Ni] Ni] _P satisfies 5≤[Fe/Ni] _P /[Fe/Ni]≤200, so the number density of [Ni,Fe]-P precipitates in the alloy can be ensured, and the coarsening of precipitates can be suppressed , Excellent heat resistance and stress relaxation resistance.

In addition, the [Ni, Fe]-P-based precipitates refer to ternary precipitates of Ni-Fe-P, and sometimes other elements are contained in these, such as main components Cu, Zn, Sn, impurities O , S, C, Cr, Mo, Mn, Mg, Zr, Ti and other multi-system precipitates. In addition, the [Ni, Fe]-P-based precipitates exist in the form of phosphides or solid-solution phosphorus alloys.

In addition, the copper alloy for electrical and electronic equipment according to the present invention is characterized in that the copper alloy for electrical and electronic equipment contains more than 2 mass % and 36.5 mass % of Zn, 0.1 mass % and 0.9 mass % of Sn, 0.15% by mass to less than 1.0% by mass of Ni, 0.005% by mass to 0.1% by mass of P, Fe and Co, and the total content of Fe and Co is 0.001% by mass to 0.1% by mass (wherein, Contains 0.001% by mass to 0.1% by mass of Fe), the remainder is composed of Cu and unavoidable impurities, and the ratio of the total content of Ni, Fe, and Co to the content of P (Ni+Fe+Co)/P is expressed in atoms In terms of ratio, it satisfies 3<(Ni+Fe+Co)/P<30, and the ratio of the content of Sn to the total content of Ni, Fe and Co, Sn/(Ni+Fe+Co), satisfies 0.3 in terms of atomic ratio. <Sn/(Ni+Fe+Co)<2.7, and the ratio of the total content of Fe and Co to the content of Ni (Fe+Co)/Ni satisfies 0.002≤(Fe+Co)/Ni< 0.6, and there are [Ni, (Fe, Co)]-P-based precipitates in the parent phase, and the [Ni, (Fe, Co)]-P-based precipitates contain at least one of Fe and Co , and contains Ni and P, the atomic ratio [(Fe+Co)/Ni] of the total content of Fe and Co to the content of Ni relative to the overall alloy, the [Ni, (Fe, Co)]-P precipitate The atomic ratio of the total content of Fe and Co to the content of Ni [(Fe+Co)/Ni] _P satisfies 5≤[(Fe+Co)/Ni] _P /[(Fe+Co)/Ni]≤200 .

According to the copper alloy for electronic and electrical equipment of the above-mentioned constitution, Ni, Fe, Co are added together with P, and the mutual addition ratio of Sn, Ni, Fe, Co, and P is limited, and there is a tendency of precipitation from the parent phase (α-phase main body). [Ni, (Fe, Co)]-P-based precipitates containing at least one of Fe and Co, and Ni and P. Among them, the atomic ratio [(Fe+Co)/Ni] of the total content of Fe and Co to the content of Ni in the entire alloy, Fe and Co in the [Ni, (Fe, Co)]-P system precipitates The atomic ratio [(Fe+Co)/Ni] _P of the total content of Co to the content of Ni satisfies 5≤[(Fe+Co)/Ni] _P /[(Fe+Co)/Ni]≤200, thus ensuring The number density of [Ni, (Fe, Co)]-P-based precipitates in the alloy, and the coarsening of the precipitates is suppressed, and the heat resistance and stress relaxation resistance are excellent.

In addition, the [Ni, (Fe, Co)]-P system precipitates refer to the ternary system precipitates of Ni-Fe-P and Ni-Co-P or the quaternary system of Ni-Fe-Co-P Precipitates, and sometimes other elements are included in these, such as multi-system precipitates containing main components Cu, Zn, Sn, impurities O, S, C, Cr, Mo, Mn, Mg, Zr, Ti, etc. In addition, the [Ni, (Fe, Co)]-P-based precipitates exist in the form of phosphides or solid-solution phosphorus alloys.

Here, in the copper alloy for electrical and electronic equipment of the present invention, it is preferable that the average particle diameter of [Ni,Fe]-P-based precipitates containing Fe, Ni, and P is set to be 100 nm or less.

In addition, in the copper alloy for electronic and electrical equipment of the present invention, the average particle size of [Ni, (Fe, Co)]-P-based precipitates containing at least one of Fe and Co, Ni, and P is set to Below 100nm.

In these cases, the average particle size of [Ni, Fe]-P-based precipitates containing Fe, Ni, and P, or [Ni, (Fe, Co)] containing at least one of Fe and Co, Ni, and P - The average particle size of the P-based precipitates is set to 100nm or less, so fine [Ni, Fe]-P-based precipitates or [Ni, (Fe, Co)]-P-based precipitates can be produced at a sufficient number density distribution, and reliably improve heat resistance and stress relaxation resistance.

The copper alloy sheet for electrical and electronic equipment of the present invention is characterized in that it is composed of a rolled material of the above-mentioned copper alloy for electrical and electronic equipment, and has a thickness in the range of 0.05 mm to 3.0 mm.

A rolled plate sheet (strip) of such a thickness is preferably used for connectors, other terminals, movable conductive pieces of electromagnetic relays, lead frames, and the like.

The conductive member for electrical and electronic equipment of the present invention is characterized in that it is composed of the above-mentioned copper alloy thin plate for electrical and electronic equipment. In addition, the conductive member for electrical and electronic equipment in the present invention refers to terminals, connectors, relays, lead frames, and the like.

The terminal of the present invention is characterized in that it is composed of the above-mentioned copper alloy thin plate for electronic and electrical equipment. In addition, the terminals in the present invention include connectors and the like.

The conductive member and terminal for electrical and electronic equipment according to these configurations are particularly excellent in heat resistance and stress relaxation resistance, and therefore can be favorably used even in a high-temperature environment.

According to the present invention, it is possible to provide a copper alloy for electrical and electronic equipment that is reliable and sufficiently excellent in heat resistance and stress relaxation resistance, and excellent in strength, a copper alloy sheet for electrical and electronic equipment using the copper alloy for electrical and electronic equipment, and an electronic equipment. Conductive parts and terminals for electrical equipment.

Description of drawings

FIG. 1 is a flow chart showing an example of steps of the method for producing a copper alloy for electrical and electronic equipment according to the present invention.

Detailed ways

Hereinafter, an embodiment of the present invention, that is, a copper alloy for electronic and electrical equipment will be described.

This embodiment, that is, the copper alloy for electrical and electronic equipment has a composition containing more than 2% by mass to 36.5% by mass of Zn, 0.1 to 0.9% by mass of Sn, and 0.15 to less than 1.0% by mass of Ni. , 0.005% by mass to 0.1% by mass of P, 0.001% by mass to 0.1% by mass of Fe, and the remainder consists of Cu and unavoidable impurities.

Furthermore, as the mutual content ratio of each alloy element, it is determined as: the ratio (Ni+Fe)/P of the total content of Ni and Fe to the content of P satisfies the following formula (1) in terms of atomic ratio:

3<(Ni+Fe)/P<30...(1)

Moreover, the ratio Sn/(Ni+Fe) of the content of Sn to the total content of Ni and Fe satisfies the following formula (2) in terms of atomic ratio:

0.3<Sn/(Ni+Fe)<2.7...(2)

And, the ratio Fe/Ni of the content of Fe and the content of Ni satisfies the following formula (3) in terms of atomic ratio:

0.002≤Fe/Ni＜0.6...(3)

Here, in the copper alloy for electrical and electronic equipment according to this embodiment, [Ni,Fe]-P-based precipitates containing Fe, Ni, and P exist in the parent phase, and the Fe content and Ni content relative to the entire alloy The atomic ratio [Fe/Ni] of the content, the atomic ratio [Fe/Ni] _P of the content of Fe in the [Ni, Fe]-P system precipitate and the content of Ni satisfies the following formula (4):

5≤〔Fe/Ni〕 _P /〔Fe/Ni〕≤200...(4)

In addition, in the copper alloy for electronic and electrical equipment according to the present embodiment, Co may be contained in addition to the above-mentioned Zn, Sn, Ni, P, and Fe. In this case, the total content of Fe and Co is set to 0.001% by mass to 0.1% by mass (wherein Fe is contained in an amount of 0.001% by mass to 0.1% by mass).

In this case, the mutual content ratio of each alloy element is determined as: the ratio (Ni+Fe+Co)/P of the total content of Ni, Fe and Co to the content of P satisfies the following formula ( 1'):

3<(Ni+Fe+Co)/P<30...(1′)

Moreover, the ratio Sn/(Ni+Fe+Co) of the content of Sn to the total content of Ni, Fe and Co satisfies the following formula (2'):

0.3<Sn/(Ni+Fe+Co)<2.7...(2′)

Moreover, the ratio (Fe+Co)/Ni of the total content of Fe and Co to the content of Ni satisfies the following formula (3') in terms of atomic ratio:

0.002≤(Fe+Co)/Ni<0.6...(3').

In addition, when Co is added, [Ni, (Fe, Co)]-P-based precipitates exist in the matrix phase, and the [Ni, (Fe, Co)]-P-based precipitates contain Fe and Co. At least one or more of them, containing Ni and P, the atomic ratio of the total content of Fe and Co to the content of Ni relative to the entire alloy [(Fe+Co)/Ni], [Ni, (Fe, Co)] - The atomic ratio [(Fe+Co)/Ni] of the total content of Fe and Co in the P-based precipitate to the Ni content [(Fe+Co)/Ni] _P satisfies the following formula (4'):

5≤[(Fe+Co)/Ni] _P /[(Fe+Co)/Ni]≤200...(4').

Here, the reason for specifying the component composition of the alloy and the composition in the precipitate as described above will be described below.

(Zn: more than 2% by mass and not more than 36.5% by mass)

Zn is a basic alloy element in the copper alloy targeted in this embodiment, and is an element effective in improving strength and elasticity. In addition, since Zn is cheaper than Cu, it is also effective for reducing the material cost of copper alloys. When Zn is 2% by mass or less, the material cost reduction effect cannot be sufficiently obtained. On the other hand, when Zn exceeds 36.5 mass %, corrosion resistance will fall, and cold rollability will also fall.

Therefore, the content of Zn is made within the range of more than 2 mass % and 36.5 mass % or less. In addition, the Zn content is within the above range, preferably within a range of 5% by mass to 33% by mass, more preferably within a range of 7% by mass to 27% by mass. More preferably, it exists in the range of 7 mass % or more and 12 mass % or less.

(Sn: 0.1% by mass to 0.9% by mass)

The addition of Sn has the effect of improving the strength, which is beneficial to improve the reusability of the Sn-plated Cu-Zn alloy material. Furthermore, according to studies by the inventors of the present invention, it has been clarified that coexistence of Sn and Ni also contributes to the improvement of the stress relaxation resistance characteristic. When Sn is less than 0.1% by mass, these effects cannot be sufficiently obtained. On the other hand, if Sn is greater than 0.9% by mass, the hot workability and cold rolling properties are reduced, and cracks may occur during hot rolling or cold rolling, and lead to electrical conductivity. rate also fell.

Therefore, the content of Sn is set within the range of not less than 0.1% by mass and not more than 0.9% by mass. In addition, the content of Sn is within the above range, and particularly preferably within a range of 0.2% by mass or more and 0.8% by mass or less.

(Ni: 0.15% by mass to less than 1.0% by mass)

By adding Ni together with P, Ni-P-based precipitates can be precipitated from the parent phase (α-phase main body), and by adding Fe and P together, [Ni, Fe] can be precipitated from the parent phase (α-phase main body)- When the P-based precipitates are added together with Fe, Co, and P, [Ni, (Fe, Co)]-P-based precipitates can be precipitated from the parent phase (α-phase main body). The average crystal grain size, and can improve strength, bending workability, and stress corrosion cracking resistance. Furthermore, the presence of these precipitates can greatly improve the stress relaxation resistance characteristics. Furthermore, by allowing Ni to coexist with Sn, Fe, and P and, if necessary, Co to coexist, it is also possible to improve the solid solution strengthening. Here, when the amount of Ni added is less than 0.15% by mass, the stress relaxation resistance cannot be sufficiently improved. On the other hand, when the amount of Ni added is 1.0% by mass or more, solid-solution Ni increases and electrical conductivity decreases, and the cost increases due to an increase in the amount of expensive Ni raw material used.

Therefore, the Ni content is set within a range of not less than 0.15% by mass and less than 1.0% by mass. In addition, the content of Ni is within the above-mentioned range, and it is particularly preferable to set it within the range of 0.2% by mass or more and less than 0.8% by mass.

(P: 0.005% by mass to 0.1% by mass)

The combination of P and Ni is high, and if an appropriate amount of P is contained together with Ni, Ni-P-based precipitates can be precipitated, and by adding together with Fe and P, [Ni, [Ni, (Fe, Co)]-P-based precipitates can be precipitated from the parent phase (α-phase main body) by adding Fe]-P-based precipitates together with Fe, Co, and P. Stress relaxation resistance can be improved by the presence of these Ni—P-based precipitates, [Ni,Fe]-P-based precipitates, and [Ni,(Fe,Co)]-P-based precipitates. Here, when the P amount is less than 0.005% by mass, it is difficult to sufficiently separate out Ni-P-based precipitates, [Ni, Fe]-P-based precipitates, and [Ni, (Fe, Co)]-P-based precipitates, thereby failing to sufficiently Improves stress relaxation resistance properties. On the other hand, if the amount of P exceeds 0.1% by mass, the amount of solid solution of P in the alloy increases, the electrical conductivity decreases, and the rollability decreases to easily cause cold cracking.

Therefore, the content of P is made within the range of 0.005 mass % or more and 0.1 mass % or less. The content of P is within the above range, and particularly preferably within a range of 0.01% by mass to 0.08% by mass.

In addition, since P is an element that is unavoidably mixed in many cases from the melting raw material of the copper alloy, in order to limit the content of P as described above, it is preferable to select the melting raw material appropriately.

(Fe: 0.001% by mass to 0.1% by mass)

If Fe is added together with Ni and P, [Ni, Fe]-P precipitates can be precipitated from the parent phase (α-phase main body), and by adding a small amount of Co, [Ni, Fe]-P system precipitates can be precipitated from the parent phase (α-phase main body). , (Fe, Co)]-P precipitates. The effect of pinning grain boundaries during recrystallization by these [Ni, Fe]-P-based precipitates or [Ni, (Fe, Co)]-P-based precipitates can control the average grain size and improve Strength, bending processability, stress corrosion cracking resistance. Furthermore, the presence of these precipitates can greatly improve both the stress relaxation resistance characteristic and the heat resistance. Here, when the content of Fe is less than 0.001% by mass, the effect of improving both the stress relaxation resistance and heat resistance due to the addition of Fe cannot be obtained. On the other hand, if the content of Fe exceeds 0.1% by mass, the effect of improving the two properties of stress relaxation resistance and heat resistance cannot be obtained, and the amount of solid-solution Fe will decrease, and the electrical conductivity will decrease, and the cold rollability will also deteriorate. decline.

Therefore, in the present embodiment, when Fe is added, the content of Fe is set within a range of 0.001% by mass or more and 0.1% by mass or less. In addition, the content of Fe is within the above-mentioned range, and it is particularly preferable to set it within the range of 0.002% by mass or more and 0.08% by mass or less.

(Total content of Fe and Co: 0.001% by mass to 0.1% by mass)

When Co is added, it is considered that a part of Fe is substituted with Co. By adding Fe and Co, [Ni, (Fe, Co)]-P-based precipitates can be precipitated from the parent phase (α-phase main body). The effect of pinning grain boundaries during recrystallization by the [Ni, (Fe, Co)]-P-based precipitates can control the average grain size and improve strength, bending workability, and stress corrosion cracking resistance. . Furthermore, the presence of the [Ni, (Fe, Co)]-P-based precipitates can significantly improve both the stress relaxation resistance and heat resistance. Here, when the total content of Fe and Co is less than 0.001% by mass, the effect of improving both the stress relaxation resistance and heat resistance due to the addition of Fe and Co cannot be sufficiently obtained. On the other hand, if the total content of Fe and Co is more than 0.1% by mass, no further improvement effect on the two characteristics of stress relaxation resistance and heat resistance can be obtained, and the amount of solid-solution Fe and solid-solution Co increases, and the electrical conductivity decreases. , and the cold rollability also decreased.

Therefore, in the present embodiment, when both Fe and Co are added, the content of Fe is set to 0.001 mass % or more and 0.1 mass % or less, and the total content of Fe and Co is set to 0.001 mass % or more and Within the range of 0.1% by mass or less. In addition, the total content of Fe and Co is within the above-mentioned range, and it is particularly preferable to set it in the range of 0.002% by mass or more and 0.08% by mass or less.

The rest of the above elements should basically be Cu and unavoidable impurities. Here, examples of unavoidable impurities include Co, Al, Ag, B, Ba, Hf, V, Nb, Ta, Mo, W, Re, Ru, Os, O, S, Se, Rh, Ir, Pd, Pt, Au, Cd, Ga, In, Li, Ge, As, Sb, Tl, Pb, Bi, C, Be, N, H, Hg, Mg, Ti, Cr, Zr, Ca, Sr, Y, Mn, Te, Si, Sc and rare earth elements, etc. These unavoidable impurities are preferably small, and the total amount is preferably 0.3% by mass or less even when waste materials are used as raw materials. The more preferable total amount of unavoidable impurities is 0.2 mass % or less, and the most preferable total amount is 0.1 mass % or less.

In addition, in the present embodiment, that is, the copper alloy for electrical and electronic equipment, not only is the range of the individual addition amount of each alloy element adjusted as described above, but also the mutual ratio of the contents of the respective elements is limited to an atomic ratio. It is also important to satisfy the above formulas (1) to (4). Furthermore, when Co is added, it is important to limit to satisfy the formulas (1') to (4'). Therefore, the reason for limitation of formula (1)-(4) and formula (1')-(4') is demonstrated below.

Formula (1): 3<(Ni+Fe)/P<30

When the ratio of (Ni+Fe)/P is 3 or less, the stress relaxation resistance and heat resistance will decrease with the increase of the proportion of solid solution P, and the electrical conductivity will also decrease due to the solid solution P, and the rollability will decrease On the other hand, cold-rolling cracks tend to occur, and bending workability also decreases. On the other hand, when the ratio of (Ni+Fe)/P is 30 or more, the electrical conductivity decreases due to the increase in the ratio of Ni and Fe in solid solution, and the cost of the expensive Ni raw material is relatively increased, resulting in an increase in cost. . Therefore, the (Ni+Fe)/P ratio is limited within the above range. In addition, the (Ni+Fe)/P ratio is within the above range, and preferably within a range of more than 3 and 20 or less. More preferably, it exists in the range of more than 3 and 15 or less.

Formula (2): 0.3<Sn/(Ni+Fe)<2.7

When the Sn/(Ni+Fe) ratio is 0.3 or less, sufficient effects of improving stress relaxation resistance and heat resistance cannot be exhibited. On the other hand, when the Sn/(Ni+Fe) ratio is 2.7 or more, the amount of Ni is relatively and the amount of Ni—P-based precipitates decreases, so that both stress relaxation resistance and heat resistance cannot be improved. Therefore, the Sn/(Ni+Fe) ratio is limited within the above range.

In addition, the Sn/(Ni+Fe) ratio is within the above range, and particularly preferably within a range of greater than 0.3 and 1.5 or less.

Formula (3): 0.002≤Fe/Ni＜0.6

When the Fe/Ni ratio is less than 0.002, the strength is lowered, and the amount of expensive Ni used as a raw material is relatively increased, leading to an increase in cost. On the other hand, when Fe/Ni ratio is 0.6 or more, sufficient stress relaxation resistance characteristic and heat resistance improvement effect cannot be exhibited. Therefore, the Fe/Ni ratio is limited within the above range. In addition, the Fe/Ni ratio is within the above range, and particularly preferably within a range of 0.002 or more and 0.4 or less. More preferably, it exists in the range of 0.002 or more and 0.2 or less.

Formula (4): 5≤〔Fe/Ni〕 _P /〔Fe/Ni〕≤200

The atomic ratio [Fe/Ni] of the content of Fe to the content of Ni in [Ni,Fe] _-P -based precipitates is also important. The atomic ratio [Fe/Ni] of the Fe content to the Ni content of the entire alloy is also important. When the ratio of [Fe/Ni] _P /[Fe/Ni] is less than 5, the number density of [Ni,Fe]-P-based precipitates becomes low, and sufficient stress relaxation resistance and heat resistance cannot be obtained. improvement. On the other hand, when the ratio of [Fe/Ni] _P /[Fe/Ni] is greater than 200, the precipitates become Fe-P-based precipitates, the size of the precipitates becomes large, and the number density becomes low. Both properties of stress relaxation resistance and heat resistance are improved. Therefore, the [Fe/Ni] _P /[Fe/Ni] ratio is limited to the above range. In addition, the [Fe/Ni] _P /[Fe/Ni] ratio is within the above range, and particularly preferably within a range of 10 or more and 100 or less. More preferably, it exists in the range of more than 15 and 75 or less.

Formula (1'): 3<(Ni+Fe+Co)/P<30

When Fe and Co are added, it is considered that a part of Fe may be substituted by Co, and the formula (1') also basically conforms to the formula (1). Here, when the (Ni+Fe+Co)/P ratio is 3 or less, the stress relaxation resistance and heat resistance decrease due to the increase in the proportion of solid-solution P, and the electrical conductivity also decreases due to the solid-solution P, and Rollability decreases, cold rolling cracks are likely to occur, and bending workability also decreases. On the other hand, if the (Ni+Fe+Co)/P ratio is 30 or more, the electrical conductivity decreases due to the increase in the proportion of Ni, Fe, and Co in solid solution, and the amount of expensive Co and Ni raw materials used is relatively large. Increases lead to increased costs. Therefore, the (Ni+Fe+Co)/P ratio is limited within the above range. In addition, the (Ni+Fe+Co)/P ratio is within the above range, and preferably within a range of more than 3 and 20 or less. More preferably, it exists in the range of more than 3 and 15 or less.

Formula (2'): 0.3<Sn/(Ni+Fe+Co)<2.7

The formula (2') in the case of adding Fe and Co also conforms to the formula (2). When the Sn/(Ni+Fe+Co) ratio is 0.3 or less, sufficient effects of improving stress relaxation resistance and heat resistance cannot be exhibited. On the other hand, if the Sn/(Ni+Fe+Co) ratio is 2.7 or more, Then, the amount of (Ni+Fe+Co) decreases relatively, and the amount of [Ni, (Fe, Co)]-P-based precipitates decreases, resulting in a decrease in stress relaxation resistance and heat resistance. Therefore, the Sn/(Ni+Fe+Co) ratio is limited within the above range. In addition, the Sn/(Ni+Fe+Co) ratio is within the above range, and particularly preferably within a range of greater than 0.3 and 1.5 or less.

Formula (3'): 0.002≤(Fe+Co)/Ni＜0.6

When Fe and Co are added, the ratio of the total content of Fe and Co to the Ni content is also important. When the (Fe+Co)/Ni ratio is 0.6 or more, the stress relaxation resistance and heat resistance are lowered, and the cost increases due to an increase in the usage-amount of an expensive Co raw material. When the (Fe+Co)/Ni ratio is less than 0.002, the strength is lowered, and the amount of expensive Ni used as a raw material is relatively increased, leading to an increase in cost. Therefore, the (Fe+Co)/Ni ratio is limited within the above range. In addition, the (Fe+Co)/Ni ratio is within the above range, and particularly preferably within a range of 0.002 or more and 0.4 or less. More preferably, it exists in the range of 0.002 or more and 0.2 or less.

Formula (4'): 5≤[(Fe+Co)/Ni] _P /[(Fe+Co)/Ni]≤200

When Fe and Co are added, the atomic ratio [(Fe+Co)/Ni] _P and The atomic ratio [(Fe+Co)/Ni] of the total content of Fe and Co in the entire alloy to the content of Ni is also important. When the [(Fe+Co)/Ni] _P /[(Fe+Co)/Ni] ratio is less than 5, the number density of [Ni, (Fe, Co)]-P precipitates becomes low, and Improvement in stress relaxation resistance and heat resistance could not be obtained. On the other hand, when the [(Fe+Co)/Ni] _P /[(Fe+Co)/Ni] ratio exceeds 200, the precipitates become (Fe, Co)-P-based precipitates, and the size of the precipitates changes. If it is large, the number density will also be low, so the improvement of stress relaxation resistance and heat resistance cannot be obtained.

Therefore, the [(Fe+Co)/Ni] _P /[(Fe+Co)/Ni] ratio is limited to the above range. In addition, the [(Fe+Co)/Ni] _P /[(Fe+Co)/Ni] ratio is within the above range, and particularly preferably within a range of 10 or more and 100 or less. More preferably, it exists in the range of more than 15 and 75 or less.

Electronic and electrical equipment adjusted so as to satisfy the formulas (1) to (3) or the formulas (1') to (3') as described above, not only setting the individual content of each alloy element, but also as the ratio of each element to each other In copper alloys, [Ni, Fe]-P-based precipitates or [Ni, (Fe, Co)]-P-based precipitates are dispersed and precipitated from the parent phase (α-phase main body). Moreover, it is considered that the composition ratio in the precipitate is specified in such a manner as to satisfy the above-mentioned formula (4) or formula (4'), so that the [Ni, Fe]-P system precipitate or the [Ni, (Fe, Co)]-P The size of the precipitates is miniaturized, the number density can be ensured, and the stress relaxation resistance and heat resistance can be reliably improved.

In addition, in the present embodiment, the average particle diameter of the [Ni,Fe]-P-based precipitates containing Fe, Ni, and P is set to be 100 nm or less. In addition, the average particle diameter of [Ni, (Fe, Co)]-P-based precipitates containing Fe, Co, Ni, and P is set to be 100 nm or less.

Thus, the average particle size of [Ni,Fe]-P-based precipitates and the average particle size of [Ni,(Fe,Co)]-P-based precipitates are considered to be as fine as 100nm or less, thereby reliably improving stress relaxation resistance. and heat resistance. The average particle diameter of the precipitates is more preferably 5 nm or more and 50 nm or less. '

Next, a preferred example of the manufacturing method of the copper alloy for electrical and electronic devices according to the above-mentioned embodiment will be described with reference to the flowchart shown in FIG. 1 .

[Melting/casting process: S01]

First, a copper alloy molten metal having the aforementioned composition is melted. As the copper raw material, 4NCu (oxygen-free copper, etc.) having a purity of 99.99% by mass or higher is preferably used, but scrap may be used as the raw material. In addition, an atmospheric atmosphere furnace may be used for melting, but a vacuum furnace, an atmosphere furnace in an inert gas atmosphere or a reducing atmosphere may be used in order to suppress oxidation of added elements.

Next, the copper alloy molten metal whose composition has been adjusted is cast by an appropriate casting method using a vertical casting furnace or a horizontal casting furnace, such as a batch casting method such as mold casting, or a continuous casting method or a semi-continuous casting method. , to obtain an ingot (such as a flat ingot).

[Heating process: S02]

Subsequently, if necessary, homogenization heat treatment is performed in order to eliminate segregation of the ingot and to homogenize the structure of the ingot. In addition, solution heat treatment is performed in order to dissolve crystallization and precipitates. The conditions of these heat treatments are not particularly limited, but generally, heating at 600° C. to 1000° C. for 1 second to 24 hours is sufficient. When the holding temperature is lower than 600° C. or the holding time is shorter than 5 minutes, sufficient homogenization effect or solid solution effect may not be obtained. On the other hand, if the holding temperature exceeds 1000° C., the segregation site may be partially melted, and the holding time exceeding 24 hours will only lead to an increase in cost. The cooling conditions after the heat treatment may be appropriately determined, but usually water quenching is sufficient. In addition, after the heating step S02 , face cutting is performed as necessary.

〔Heat processing process: S03〕

Next, the ingot may be hot-worked after the aforementioned heating step S02 in order to increase the efficiency of the rough machining and to homogenize the structure. The conditions of this thermal processing are not particularly limited, but generally, it is preferable to set the starting temperature at 600° C. to 1000° C., the finishing temperature at 300° C. to 850° C., and the processing ratio at about 10% to 99%. In addition, the heating of the ingot until reaching the hot working start temperature may also be used as the aforementioned heating step S02. That is, after heating in the heating step S02, the thermal processing may be started at the above-mentioned thermal processing start temperature without cooling to around room temperature. The cooling conditions after hot working may be appropriately determined, but usually water quenching is sufficient. In addition, after hot working, face cutting is performed as necessary. The processing method of hot working is not particularly limited, but when the final shape is a plate or a strip, hot rolling is applied and rolled to a plate thickness of about 0.5 mm to 50 mm. Furthermore, when the final shape is a wire or a rod, extrusion and groove rolling are applied, and when the final shape is a block shape, forging and pressing may be applied. In addition, generally, the hot working process does not need to be performed on the ingot produced by the horizontal continuous casting method.

〔Intermediate plastic processing process: S04〕

Next, intermediate plastic working is performed on the ingot subjected to the homogenization treatment in the heating step S02 or the hot-worked material subjected to the hot working step S03 such as hot rolling. The temperature conditions in the intermediate plastic working step S04 are not particularly limited, but are preferably within the range of -200°C to +200°C, which is cold working or warm working. The working ratio of the intermediate plastic working is not particularly limited, but is generally set at about 10% or more and 99% or less. The processing method is not particularly limited, but when the final shape is a plate shape or a strip shape (a shape wound into a coil), it may be rolled to a plate thickness of about 0.05 mm to 15 mm by applying rolling. In addition, when the final shape is a wire or a rod, extrusion and groove rolling can be applied, and when the final shape is a block shape, forging and pressing can be applied.

〔Intermediate heat treatment process: S05〕

Next, after the intermediate plastic working step S04, an intermediate heat treatment also serving as a solution heat treatment is performed. By performing this intermediate heat treatment, fine [Ni, Fe]-P-based precipitates or [Ni, (Fe, Co)]-P-based precipitates are solid-dissolved in the matrix phase. Here, in the intermediate heat treatment, a batch type heating furnace may be used, or a continuous annealing line may be used. Furthermore, when performing intermediate heat treatment using a batch type heating furnace, it is preferable to heat at the temperature of 600 degreeC or more and 1000 degreeC or less for 5 minutes or more and 24 hours or less. In addition, in the case of performing intermediate heat treatment using a continuous annealing line, it is preferable to set the heating temperature to 650° C. to 1000° C., and not to hold the temperature within this range, or to hold it for 1 second to 5 seconds. Minutes or so. As described above, the heat treatment conditions in the intermediate heat treatment step S05 differ depending on the specific method of performing the heat treatment.

Furthermore, the atmosphere of the intermediate heat treatment is preferably a non-oxidizing atmosphere (a nitrogen atmosphere, an inert gas atmosphere, or a reducing atmosphere).

The cooling conditions after the intermediate heat treatment are not particularly limited, but generally, cooling may be performed at a cooling rate of about 2000°C/sec to 100°C/hour.

In addition, the intermediate plastic working step S04 and the intermediate heat treatment step S05 may be repeated for complete solid solution.

〔Finish plastic processing process: S06〕

After the intermediate heat treatment step S05, finishing plastic working is performed up to final dimensions and final shape. The processing method in finishing plastic processing is not particularly limited, but when the final product form is in the form of a plate or a strip, rolling (cold rolling) can be applied to a thickness of about 0.05mm to 3.0mm. . In addition, forging, stamping, groove rolling, etc. can also be applied depending on the form of the final product. The processing rate may be appropriately selected according to the final plate thickness and final shape, but is preferably within a range of 1% or more and 80% or less. When the working ratio is less than 1%, the effect of improving the yield strength cannot be sufficiently obtained. On the other hand, if it exceeds 80%, the recrystallized structure will be substantially lost and become a processed structure, which may lower the bending workability. In addition, the working ratio is preferably set at 5% or more and 80% or less, more preferably 10% or more and 80% or less. After finishing plastic working, although it can be used as a product as it is, it is usually preferable to further perform finishing heat treatment.

〔Finish heat treatment process: S07〕

After the finishing plastic working, the finishing heat treatment step S07 is performed for improving the stress relaxation resistance and heat resistance, low-temperature annealing and curing, or for removing residual strain as required. This finishing heat treatment is preferably performed at a temperature in the range of 250° C. to 600° C. for 1 hour to 48 hours. When the heat treatment temperature is high temperature, heat treatment may be performed for a short time, and when the heat treatment temperature is low, heat treatment may be performed for a long time. When the temperature of the finishing heat treatment is less than 250° C. or the time of the finishing heat treatment is less than 1 hour, a sufficient effect of strain relief may not be obtained. On the other hand, when the temperature of the finishing heat treatment exceeds 600°C, recrystallization may occur, and the time of the finishing heat treatment exceeding 48 hours will only lead to an increase in cost.

In addition, in the present embodiment, the atomic ratio of the content of Fe in the [Ni,Fe]-P-based precipitate to the content of Ni is controlled by the rate of temperature increase. Preferably, the rate of temperature increase is 0.1° C./minute or more and 10° C./minute or less.

As described above, the Cu—Zn—Sn based alloy material in the final product form can be obtained. In particular, when rolling is applied as a working method, a Cu—Zn—Sn alloy thin plate (strip material) having a plate thickness of about 0.05 mm to 3.0 mm can be obtained.

This kind of thin plate can be used as it is in conductive parts for electrical and electronic equipment, but usually one or both sides of the plate are plated with Sn with a film thickness of about 0.1 to 10 μm, and used as a Sn-plated copper alloy strip for connection Conductive parts for electronic and electrical equipment such as devices and other terminals. The method of Sn plating at this time is not particularly limited. Also, depending on circumstances, reflow treatment may be performed after plating.

In the copper alloy for electrical and electronic equipment according to the present embodiment constituted as above, [Ni, Fe]-P-based precipitates are appropriately present from the parent phase mainly composed of α-phase, and the content of Fe and Ni relative to the entire alloy The atomic ratio [Fe/Ni] of the content, the atomic ratio [Fe/Ni] of the content of Fe in the [Ni,Fe]-P system precipitates to the content of Ni [Fe/Ni] _P is set within the range of 5 or more and 200 or less , the stress relaxation resistance and heat resistance are sufficiently excellent, and the strength (yield strength) also becomes high.

Also, when Fe and Co are added, [Ni, (Fe, Co)]-P-based precipitates are appropriately present from the parent phase of the α-phase main body, and the (Fe, Co) +Co) content and Ni content atomic ratio [(Fe+Co)/Ni], [Ni, (Fe, Co)]-P system precipitates (Fe+Co) content and Ni content The atomic ratio [(Fe+Co)/Ni] _P is set in the range of 5 to 200, so the stress relaxation resistance and heat resistance are sufficiently excellent, and the strength (yield strength) is also high.

This embodiment, that is, the copper alloy sheet for electrical and electronic equipment is composed of the rolled material of the above-mentioned copper alloy for electrical and electronic equipment, so it is excellent in stress relaxation resistance and heat resistance, and can be preferably used in connectors, other terminals, busbars, electromagnetic coils, etc. Relay movable conductive sheet, lead frame, etc.

In this embodiment, the conductive parts and terminals for electrical and electronic equipment are composed of the above-mentioned copper alloy for electrical and electronic equipment and the copper alloy sheet for electrical and electronic equipment, so they are excellent in stress relaxation resistance and heat resistance. Stress relaxation is less likely to occur, and there is less decrease in strength (hardness) at high temperatures, so it is excellent in reliability. In addition, it is possible to reduce the thickness of conductive members and terminals for electrical and electronic equipment.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, In the range which does not deviate from the technical idea of this invention, it can change suitably.

For example, an example of the production method has been described, but the present invention is not limited thereto, and the finally obtained copper alloy for electrical and electronic equipment may satisfy the composition range and the composition of precipitates specified in the present invention.

Example

Hereinafter, the results of confirmation experiments conducted to confirm the effects of the present invention are shown together with comparative examples as examples of the present invention. In addition, the following examples are used to illustrate the effects of the present invention, and the configurations, processes, and conditions described in the examples do not limit the technical scope of the present invention.

First, prepare a raw material consisting of Cu-40 mass % Zn master alloy and oxygen-free copper ( _{ASTMB152C10100} ) with a purity of 99.99 mass % or more, put it in a high-purity graphite crucible, and use a horizontal continuous Casting furnace for melting. Various additive elements were added to copper alloy molten metal, alloy molten metal having the composition shown in Table 1 to Table 3 was melted, and an ingot was produced using a carbon mold. After that, it is cut into about 11 mm in thickness x about 80 mm in width x about 200 mm in length.

Next, each cut ingot was kept at 800° C. for 4 hours in an Ar gas atmosphere as heat treatment (homogenization treatment), and then water quenched.

Thereafter, surface grinding was performed, and intermediate plastic working and intermediate heat treatment were performed. Specifically, the rough processing was performed by cold rolling at a rolling reduction rate of 95% so that the longitudinal direction of the ingot became the rolling direction.

Thereafter, as intermediate heat treatment for solution treatment, water quenching was performed at 700° C. for a predetermined time so that the average crystal grain size after the intermediate heat treatment was about 20 μm. Thereafter, the rolled material was cut and surface ground to remove the oxide layer.

Next, cold rolling was performed at a rolling ratio of 50% as finishing plastic working. Thereafter, the temperature was raised to 350° C. at the rate of temperature increase shown in Tables 4 to 6, a finishing heat treatment was performed for a predetermined time, and water quenching was performed. Then, dicing and surface grinding were performed to manufacture a strip for property evaluation having a thickness of 0.25 mm×a width of about 180 mm.

For these strips for property evaluation, the mechanical properties (yield strength) were investigated, and the stress relaxation resistance and heat resistance were investigated, and the microstructure was further observed. The test method and measurement method for each evaluation item are as follows.

〔Observation of crystal grain size〕

The crystal grain size after the intermediate heat treatment (intermediate annealing) was measured as follows. The surface perpendicular to the rolling width direction, that is, the TD surface (Transverse direction) was used as the observation surface, and after mechanical grinding with water-resistant grinding paper and diamond abrasive grains, finishing grinding was performed with a colloidal silica solution. . After grinding, etching was performed with a mixed solution of sulfuric acid and nitric acid as an etching solution, and the metal structure was observed with an optical microscope. Crystal grain size According to the cutting method of JIS H 0501 (corresponding to ISO2624-1973), draw 5 vertical and horizontal line segments of specified length, count the number of completely cut crystal grains, and calculate the average value of the cut length Let it be an average crystal particle diameter.

〔Observation of precipitates〕

The strips for each property evaluation were observed with a transmission electron microscope (TEM: manufactured by Hitachi, Ltd., H-800, HF-2200) and an EDX analyzer (manufactured by Noran, EDX analyzer SYSTEM SIX) as follows .

After the surface and the back surface of the rolled material were mechanically ground with water-resistant grinding paper and diamond abrasive grains, samples for TEM observation were produced by the double-spray method using an electrolytic solution. Samples for TEM observation were produced at two places entering 1/4 in the thickness direction from two places on the front and back of the rolled material, respectively.

Electron beam diffraction was performed on 10 or more precipitates with particle diameters ranging from about 10 nm to 50 nm, and it was confirmed that these precipitates _were hexagonal crystals (space group: P _- 62m (189)) or a Co ₂ P-based or Fe ₂ P-based orthorhombic crystal (space group: P-nma (62)). After performing electron beam diffraction, each precipitate was further analyzed by EDX (energy dispersive X-ray spectrometry) to analyze the composition of the precipitate, and it was confirmed that the precipitate contained Fe, Co, and Ni selected from the group consisting of At least one element and P are confirmed to be one of the defined [Ni, (Fe, Co)]-P system precipitates. Then, the Fe/Ni ratio or (Fe+Co)/Ni ratio in the precipitate was calculated from the composition analysis result of the precipitate by EDX.

〔Evaluation of heat resistance〕

According to JCBA T315:2002 "Annealing Softening Characteristics Test of Copper and Copper Alloy Strips", the heat resistance was evaluated as the half-softening temperature when heat treatment was performed at each temperature for 1 hour. The half-softening temperature is defined by calculating the sum of the hardness of the strip for property evaluation and the hardness of the strip heat-treated at 700° C. for 1 hour in an electric furnace, and the temperature at which the hardness becomes half of the sum. The actual half-softening temperature is determined by plotting the hardness at 50° C. for 1 hour in the temperature range of 200 to 700° C., creating a hardness-temperature curve, and determining from the curve.

In addition, regarding the hardness, according to the microhardness test method stipulated in JIS-Z2248 (ISO7438: 2005, Metallic Materials-Bend test (MOD)), the surface of the strip material for property evaluation, that is, the ND surface (Normal Direction), was subjected to a test force of 1.96. N (=0.2kgf) Vickers hardness was measured.

〔Mechanical properties〕

Select the No. 13B test piece specified by JIS Z 2201 (corresponding to ISO6892) from the strips for property evaluation, and use JIS-Z 2241 (ISO6892-1: 2009, Metallic Materials–Tensile testing–Part 1:Method of test at room temperature (MOD)) The Young's modulus E and the 0.2% yield strength σ _0.2 were measured by the trace residual elongation method. In addition, the test pieces were selected so that the tensile direction of the tensile test and the rolling direction of the strip material for property evaluation were perpendicular to each other.

The obtained Young's modulus E was used in the stress relaxation resistance test.

〔Stress relaxation resistance characteristics〕

The stress relaxation resistance test is carried out by the cantilever thread method of the Japan Copper Association Technical Standard JCBA-T309:2004, and the sample with the Zn content greater than 2% by mass and less than 15% by mass (recorded in Table 4 ~ 6 "2-15 Zn Evaluation" column), measured the residual stress rate after holding at a temperature of 150 ℃ for 500 hours, for the samples whose Zn content was 15% by mass or more and 36.5% by mass or less ( For the samples listed in the columns of "15-36.5Zn evaluation" in Tables 4 to 6), the residual stress rate after holding at a temperature of 120° C. for 500 hours was measured.

As a test method, a test piece (10 mm in width) was selected from each property evaluation strip material in a direction perpendicular to the rolling direction, and the initial bending displacement was set so that the maximum surface stress of the test piece became 80% of the yield strength. Set to 2mm, adjust the span length. The above-mentioned maximum surface stress is determined by the following formula.

Maximum surface stress (MPa)＝1.5Etδ ₀ /Ls ²

in,

E: Young's modulus (MPa)

t: Thickness of sample (t=0.25mm)

δ ₀ : Initial bending displacement (2mm)

Ls: span length (mm).

And, the residual stress rate was calculated by the following formula.

Residual stress rate (%)=(1-δt/δ ₀ )×100

in,

δt: permanent bending displacement (mm) after keeping at 120°C for 500h, or after keeping at 150°C for 500h - permanent bending displacement (mm) after keeping at room temperature for 24h

δ ₀ : initial bending displacement (mm).

A residual stress rate of 80% or more was evaluated as "◯", and less than 80% was evaluated as "×".

About each evaluation result mentioned above. Shown in Tables 4, 5, and 6.

[Table 1]

[Example of the present invention]

[Table 2]

[Example of the present invention]

[table 3]

[comparative example]

[Table 4]

[Example of the present invention]

[table 5]

[Example of the present invention]

[Table 6]

[comparative example]

In Comparative Example 101, the atomic ratio [(Fe+Co)/Ni] of the total content of Fe and Co in the [Ni, (Co, Fe)]- _P -based precipitates to the Ni content [(Fe+Co)/Ni] and the Fe content of the entire alloy And the ratio of the atomic ratio [(Fe+Co)/Ni] of the total content of Co to the content of Ni, that is, [(Fe+Co)/Ni] _P /[(Fe+Co)/Ni] is lower than the range of the present invention , heat resistance and stress relaxation resistance are insufficient.

In Comparative Example 102, the atomic ratio [Fe/Ni] of the content of Fe in the [Ni,Fe]-P-based precipitates to the content of Ni [Fe/Ni] _P and the atomic ratio of the content of Fe in the entire alloy to the content of Ni [Fe/Ni] The ratio of /Ni], that is, [Fe/Ni] _P /[Fe/Ni], is higher than the range of the present invention, and the heat resistance and stress relaxation resistance are not sufficient.

In Comparative Example 103, the content of Fe was larger than the range of the present invention, and the heat resistance and stress relaxation resistance were insufficient.

In Comparative Example 104, neither P nor Fe was added, and the heat resistance and stress relaxation resistance were insufficient.

In Comparative Example 105, no P was added, and the heat resistance and stress relaxation resistance were insufficient.

In Comparative Example 106, the Ni content was less than the range of the present invention, and the atomic ratios of (Ni+Fe)/P, Sn/(Ni+Fe) and Fe/Ni were also outside the range of the present invention, and the heat resistance and Stress relaxation resistance characteristics were insufficient.

On the other hand, in the examples of the present invention, not only the individual content of each alloy element is within the range specified in the present invention, but also the mutual ratio of each alloy component is within the range specified in the present invention, and in [Ni, Fe ]-The atomic ratio [Fe/Ni] of the content of Fe in the _P -based precipitates to the content of Ni [Fe/Ni] The ratio of the atomic ratio [Fe/Ni] of the content of Fe in the entire alloy to the content of Ni, that is, [Fe/Ni] Ni] _P / [Fe/Ni], or the atomic ratio of the total content of Fe and Co in the precipitate of [Ni, (Co, Fe)]-P to the content of Ni [(Fe+Co)/Ni] _P The ratio of the atomic ratio [(Fe+Co)/Ni] of the total content of Fe and Co to the Ni content of the alloy as a whole, that is, [(Fe+Co)/Ni] _P /[(Fe+Co)/Ni] Within the scope of the present invention, it has been confirmed that both heat resistance and stress relaxation resistance are excellent, and it can be sufficiently applied to connectors or other terminals.

In addition, in Invention Example No. 41 shown in Table 2, Sn/(Ni+Fe+Co) shows 0.30, but this is a value expressed with a decimal point aligned with other values, and the correct value is 0.3003. That is, Sn/(Ni+Fe+Co) of Example No. 41 of the present invention falls within the scope of the present invention.

Claims (5)

1. A copper alloy for electrical and electronic equipment, characterized in that, The copper alloy for electrical and electronic equipment contains more than 2% by mass and not more than 36.5% by mass of Zn, not less than 0.1% by mass and not more than 0.9% by mass of Sn, not less than 0.15% by mass and less than 1.0% by mass of Ni, and not less than 0.005% by mass and 0.1 mass % or less of P, 0.001 mass % or more and 0.1 mass % or less of Fe, and the balance is composed of Cu and unavoidable impurities, The ratio of the total content of Ni and Fe to the content of P (Ni+Fe)/P is expressed in atomic ratio, satisfying 3<(Ni+Fe)/P<30 And, the ratio Sn/(Ni+Fe) of the content of Sn to the total content of Ni and Fe is expressed in atomic ratio, satisfying 0.3＜Sn/(Ni+Fe)＜2.7 And, the ratio [Fe/Ni] of the content of Fe to the content of Ni is expressed in atomic ratio, satisfying 0.002≤〔Fe/Ni〕＜0.6 Furthermore, there are [Ni, Fe]-P-based precipitates containing Fe, Ni, and P in the parent phase, and the [Ni, The atomic ratio [Fe/Ni] _P of the content of Fe in the Fe]-P system precipitate and the content of Ni satisfies 5≤[Fe/Ni] _P /[Fe/Ni]≤200. 2. A copper alloy for electrical and electronic equipment, characterized in that, The copper alloy for electrical and electronic equipment contains more than 2% by mass and not more than 36.5% by mass of Zn, not less than 0.1% by mass and not more than 0.9% by mass of Sn, not less than 0.15% by mass and less than 1.0% by mass of Ni, and not less than 0.005% by mass and 0.1% by mass or less of P, and Fe and Co, the total content of Fe and Co is set to 0.001% by mass to 0.1% by mass, of which Fe is contained in an amount of 0.001% by mass to 0.1% by mass, and the remainder is composed of Cu and unavoidable impurities, The ratio of the total content of Ni, Fe and Co to the content of P (Ni+Fe+Co)/P is calculated in atomic ratio, satisfying 3＜(Ni+Fe+Co)/P＜30 And, the ratio of the content of Sn to the total content of Ni, Fe and Co, Sn/(Ni+Fe+Co), in terms of atomic ratio, satisfies 0.3＜Sn/(Ni+Fe+Co)＜2.7 And, the ratio (Fe+Co)/Ni of the total content of Fe and Co to the content of Ni is expressed in atomic ratio, satisfying 0.002≤(Fe+Co)/Ni＜0.6 Moreover, there are [Ni, (Fe, Co)]-P-based precipitates in the parent phase, and the [Ni, (Fe, Co)]-P-based precipitates contain at least one of Fe and Co, and Containing Ni and P, the atomic ratio [(Fe+Co)/Ni] of the total content of Fe and Co to the content of Ni relative to the entire alloy, the [Ni, (Fe, Co)]-P precipitates The atomic ratio [(Fe+Co)/Ni] _P of the total content of Fe and Co to the content of Ni satisfies 5≤[(Fe+Co)/Ni] _P /[(Fe+Co)/Ni]≤200. 3. A copper alloy sheet for electrical and electronic equipment, characterized in that it is made of a rolled material of copper alloy for electrical and electronic equipment according to claim 1 or 2, The thickness is within the range of 0.05 mm to 3.0 mm. 4. A conductive member for electrical and electronic equipment, comprising the copper alloy thin plate for electrical and electronic equipment according to claim 3. 5. A terminal comprising the copper alloy thin plate for electronic and electrical equipment according to claim 3.