KR20170113407A - Copper alloy for electronic materials - Google Patents

Abstract

Provided is a copper alloy for electronic materials having a 0.2% proof stress and conductivity suitable for use in electronic materials and capable of improving dimensional stability when pressed.
The copper alloy for electronic materials according to the present invention is a copper alloy for electronic materials comprising 0.5 to 3.0% by weight of Co, 0.1 to 1.0% by weight of Si and the balance of Cu and unavoidable impurities. The copper alloy is 0.2% 200, and {220} of the {200} crystal planes on the surface, wherein the average crystal grain diameter in the cross-section parallel to the rolling direction is not more than 10 mu m, (I {220} + I {311}) / I {200} > / = 5.0 from the crystal plane, and the X-ray diffraction integral intensity I { .

Description

{COPPER ALLOY FOR ELECTRONIC MATERIALS}

The present invention relates to a Cu-Co-Si based alloy which is a precipitation hardening type copper alloy suitable for use in various electronic components, and in particular, proposes a technique capable of improving dimensional stability at the time of press working.

BACKGROUND ART Copper alloys for electronic materials used in various electronic components such as connectors, switches, relays, pins, terminals, and lead frames are required to have high strength and high conductivity (or thermal conductivity) as fundamental characteristics. In recent years, the demand for copper alloys used in electronic device parts has been further improved because of the recent progress in high integration, miniaturization, and thinning of electronic components.

From the viewpoint of high strength and high conductivity, the amount of precipitation hardening type copper alloy instead of the solid solution strengthening type copper alloy represented by conventional phosphor bronze, brass or the like is increasing as copper alloy for electronic materials. In precipitation hardening type copper alloy, fine solution precipitates are uniformly dispersed by aging treatment of supersaturated solid solution subjected to solution treatment, resulting in an increase in alloy strength and a decrease in amount of solid solution in copper, thereby improving electric conductivity. Therefore, it is possible to obtain a material excellent in mechanical properties such as springiness and excellent in electric conductivity and thermal conductivity.

Of the precipitation hardening type copper alloys, Cu-Ni-Si type alloys commonly referred to as Corson Alloy are representative copper alloys having relatively high conductivity, strength and bending workability, and have been actively developed in the related art It is one of the losing alloys. In this copper alloy, the strength and conductivity can be improved by precipitating fine Ni-Si intermetallic compound particles in a copper matrix.

In such a Colson type alloy, a Cu-Co-Si type alloy in which Co is added or Ni is substituted with Co is proposed for further improvement of characteristics.

The Cu-Co-Si-based alloy generally has a higher solution temperature than the Cu-Ni-Si-based alloy, making it difficult to miniaturize the crystal grains after solution treatment. On the other hand, Patent Documents 1 to 3 and the like describe a technique of controlling crystal grains by a Cu-Co-Si-based alloy.

Concretely, in Patent Document 1, it is described that improvement of the bending property and the improvement of the gaps of the mechanical properties are focused on, and the aging treatment is performed prior to the solution treatment to make the crystal grains finer. Patent Document 2 discloses that the average grain size is controlled by adjusting the finish temperature of the hot rolling and the final pass degree of the intermediate rolling to improve the plating ability. Further, Patent Document 3 describes that the bending property is improved by controlling the crystal orientation of the Cube orientation.

Such a Cu-Co-Si based alloy is generally manufactured by melting and cast ingot, followed by hot rolling, first cold rolling, solution treatment, aging treatment and final cold rolling in sequence.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2012-72470 Patent Document 2: Japanese Unexamined Patent Application Publication No. 2011-252216 Patent Document 3: JP-A-2013-32564

In recent years, with the miniaturization and thinning of electronic components, for example, the connectors incorporated therein tend to have extremely narrow widths or thinner thicknesses of the spacing (so-called pitch) or terminals of the pins arranged.

When a conventional Cu-Co-Si based alloy as described above is subjected to press working to manufacture such a small connector, the pitch greatly varies during the pressing. For example, when the pin moves up, down, left and right There was a problem of deforming. That is, according to the crystal grain diameter control as in the prior art, the dimensional stability of the press working can not be significantly improved. Such deterioration of the product greatly reduces the product ratio in the assembling process.

Particularly, in a phenomenon in which a Colson type alloy having excellent characteristics such as strength and electric conductivity is increasingly employed as a material for a connector having a narrow pitch and a long spring length as typified by a floating connector, An effective countermeasure against the problem that the dimension of the pin is not stable at the time of pressing is required.

It is an object of the present invention to solve such a problem, and an object of the present invention is to provide an electronic material which has a 0.2% proof strength and a conductivity suitable for use in electronic materials and can improve dimensional stability when press- To provide a copper alloy.

As a result of intensive studies, the inventors have found that the crystal grains of a Cu-Co-Si based alloy can be made finer and the crystal orientation can be controlled, and the crystal orientation can be controlled from the {200} crystal planes, {220} crystal planes and {311} It is possible to stabilize the pin dimension of the connector terminal at the time of press working. This fine grain refinement and crystal orientation control are carried out between the first cold rolling and the aging treatment in the conventional manufacturing process twice by the solution treatment under a predetermined condition, And the intermediate rolling of the conditions.

Under the above observation, the copper alloy for electronic materials of the present invention contains 0.5 to 3.0% by weight of Co, 0.1 to 1.0% by weight of Si, and the balance of Cu and unavoidable impurities. And the average crystal grain diameter in a rolling parallel cross section is 10 占 퐉 or less, and the X-ray diffraction integral intensity I {200} from the {200} crystal face at the surface is 10% I {200} + I {311} / I {200} from the {220} crystal plane, and the X-ray diffraction integral intensity I {311} Lt; / = 5.0.

In the copper alloy for electronic materials of the present invention, it is preferable that the difference in 0.2% proof stress minus the 0.2% proof stress in the direction perpendicular to the rolling direction from the 0.2% proof stress in the direction parallel to the direction of rolling is 50 MPa or less.

The copper alloy for an electronic material of the present invention is characterized in that the X-ray diffraction integral intensity I {200} from the {200} crystal plane on the surface and the X-ray diffraction integral intensity Io {200} (200) < / = 1.0.

The copper alloy for electronic materials of the present invention may further contain Cr in an amount of 0.5% by mass or less.

Further, Ni may be added in an amount of 2.0 mass% or less.

Further, it is preferable to further contain Zn and Sn in an amount of not more than 1.0% by mass, Mg, P, Ca and Mn in an amount of not more than 0.2% by mass respectively, and at least one of Zn, Sn, Mg, P, Ca and Mn To 2.0% by mass or less in total.

According to the copper alloy for electronic materials of the present invention, the X-ray diffraction integral intensity I {200} from the {200} crystal face at the surface and the X-ray diffraction integral intensity I {220} } Dimensional intensity after pressing can be effectively increased by satisfying the relationship of (I {220} + I {311}) / I {200}? 5.0 in the X-ray diffraction integral intensity I {311} from the crystal plane. This makes it possible to improve the product ratio at the time of manufacturing the electronic material.

Fig. 1 is a schematic diagram schematically showing a fracture surface and a front surface section formed on a press wave surface by the pressability evaluation in the embodiment. Fig.

Hereinafter, embodiments of the present invention will be described in detail.

The copper alloy for electronic materials according to one embodiment of the present invention is a copper alloy for electronic materials containing 0.5 to 3.0% by weight of Co, 0.1 to 1.0% by weight of Si and the balance of Cu and unavoidable impurities, Ray diffraction integral intensity I {200} from the {200} crystal face at the surface, and the average crystal grain diameter obtained by the rolling parallel cross section is 10 mu m or less, I {200} + I {311} / I {200} from the {220} crystal plane, and the X-ray diffraction integral intensity I {311} ≫ = 5.0.

(Addition amount of Co and Si)

Co and Si can form an intermetallic compound by carrying out an appropriate heat treatment, and the strength can be increased without deteriorating the conductivity.

If the addition amounts of Co and Si are less than 0.5% by mass of Co and less than 0.1% by mass of Si, respectively, the desired strength can not be obtained. On the other hand, when the content of Co exceeds 3.0% by mass and the content of Si exceeds 1.0% by mass, And the hot workability deteriorates further. Therefore, the addition amount of Co and Si is set to 0.5 to 3.0 mass% of Co and 0.1 to 1.0 mass% of Si.

In the Cu-Co-Si system, a higher strength is preferable than a Cu-Ni-Si system. Therefore, the Co concentration is expected to be high, preferably 1.0 mass% or more, and more preferably 1.5 mass% or more. The addition amount of Co and Si is preferably 1.0 to 2.5% by mass of Co, 0.3 to 0.8% by mass of Si, 1.5 to 2.0% by mass of Co and 0.4 to 0.6% by mass of Si.

(Amount of Cr added)

Cr can strengthen the grain boundaries in order to precipitate in the grain boundaries in the cooling process at the time of melting and casting, and it is difficult to cause cracking during hot working, so that the decrease of the product ratio can be suppressed. That is, the Cr precipitated at the grain boundary during the solution casting is reused by solution treatment and the like, but at the succeeding precipitation of the age, precipitation particles of bcc structure or Cr and a compound with Si are produced. In the conventional Cu-Ni-Si based alloy, Si which does not contribute to the precipitation of the aging is added as a mother phase to suppress the increase of the conductivity, but Cr added as a silicide forming element is added, By precipitating, the amount of solid solution Si can be reduced, and the conductivity can be increased without damaging the strength. However, when the Cr concentration exceeds 0.5% by mass, coarse secondary phase particles are easily formed, thereby deteriorating the product characteristics. Therefore, in the present invention, at most 0.5 mass% of Cr can be added. However, when the content is less than 0.03% by mass, the effect is small. Therefore, the content is preferably 0.03 to 0.5% by mass, and more preferably 0.09 to 0.3% by mass.

(Addition amount of Sn and Zn)

Sn and Zn also improve product properties such as strength, stress relaxation property, and plating ability without deteriorating the conductivity by adding a trace amount. The addition effect is exerted mainly by employment in the hair. However, when each concentration of Sn and Zn exceeds 1.0% by mass, the effect of improving the characteristics is saturated, and the composition is deteriorated. Therefore, in the present invention, Sn and Zn can be added to a maximum of 1.0 mass%, respectively. However, the total content of Sn and Zn is preferably 0.05 to 2.0% by mass, and more preferably 0.5 to 1.0% by mass since the effect is small when the total of Sn and Zn is less than 0.05% by mass.

(Addition amount of Mg, P, Ca and Mn)

The addition of trace amounts of Mg, P, Ca and Mn improves the product characteristics such as strength and stress relaxation characteristics without impairing the conductivity. The effect of addition is mainly exhibited by the employment of the parent phase, but it may be further exerted by being contained in the secondary phase particles. However, if the Mg, P, Ca and Mn concentrations exceed 0.5% by mass, the effect of improving the characteristics is saturated, and the composition is deteriorated. Therefore, in the present invention, Mg, P, Ca and Mn can be added at the maximum of 0.5 mass%, respectively. However, the total amount of Mg, P, Ca and Mn is preferably 0.01 to 0.5% by mass, more preferably 0.04 to 0.2% by mass, since the effect is small when the total of Mg, P, Ca and Mn is less than 0.01% %.

When the above-mentioned Zn, Sn, Mg, P, Ca and Mn are contained, the total amount of at least one kind selected from Zn, Sn, Mg, P, Ca and Mn is 2.0 mass% or less. When the total amount exceeds 2.0% by mass, the characteristic improving effect is saturated and the composition is deteriorated.

(Amount of Ni added)

Ni also improves the product characteristics such as conductivity, strength, stress relaxation property and plating ability by adjusting the addition amount according to the required product characteristics. The effect of the addition is mainly exhibited by the employment of the parent phase. However, the effect can be further enhanced by forming the second phase particle of the new composition, contained in the second phase particle (mainly Ni-Co-Si system or Ni-Si system precipitate) It can also be exercised. However, if the Ni addition amount exceeds 2.0% by mass, the effect of improving the characteristics is saturated and the composition is deteriorated. Therefore, in the present invention, it is possible to add Ni at maximum 2.0 mass%. However, since the effect is small at less than 0.001 mass%, it is preferably 0.001 to 2.0 mass%, more preferably 0.05 to 1.0 mass%.

(0.2% proof)

In order to satisfy the characteristics required for a predetermined electronic material such as a connector, the 0.2% proof stress in the rolling parallel direction is set to 500 MPa or more. The 0.2% proof stress in the rolling parallel direction is preferably in the range of 500 MPa to 950 MPa, more preferably 600 MPa to 950 MPa.

Further, it is preferable that the difference in 0.2% proof stress obtained by subtracting the 0.2% proof stress in the direction perpendicular to the rolling direction from the 0.2% proof stress in the rolling parallel direction is 50 MPa or less. This makes it possible to further improve the dimensional stability at the time of pressing. That is, if the difference in the 0.2% proof stress is too large, the pin of the connector tends to be deformed vertically and horizontally at the time of pressing, and the dimensional accuracy may be lowered. From this viewpoint, the smaller the difference in the 0.2% proof stress is, the more preferable it is, and more specifically, 30 MPa, and more preferably 20 MPa.

The 0.2% proof stress is measured in accordance with JIS Z2241 using a tensile tester.

(Conductivity)

The conductivity shall be not less than 60% IACS. As a result, it can be effectively used as an electronic material. The conductivity can be measured in accordance with JIS H0505. The conductivity is preferably 65% IACS or higher.

(Average crystal grain diameter)

By making the crystal grain diameter finer, high strength can be obtained. In addition, by finely reducing the crystal grain diameter in the rolling parallel cross section, it is possible to contribute to improvement of dimensional stability at the time of pressing. Therefore, the average crystal grain diameter in the rolling parallel section is set to 10 μm or less. If the average crystal grain diameter exceeds 10 占 퐉, the pressability deteriorates. From this viewpoint, the average crystal grain diameter is preferably 8 mu m or less, more preferably 6 mu m or less.

On the other hand, although the lower limit of the average crystal grain diameter is not particularly formed, if the grain size is adjusted to 2 占 퐉 or less, a part of the metal structure becomes unrecrystallized, and if the unrecrystallized portion remains, the pressing property deteriorates.

The average crystal grain diameter is measured based on JIS H0501 (cutting method).

(Integrated intensity of X-ray diffraction)

The copper alloy for electronic materials of the present invention has an X-ray diffraction integral intensity I {200} from a {200} crystal face in the surface (rolled face) obtained by X-ray diffraction (XRD) The relationship between the X-ray diffraction integral intensity I {220} and the X-ray diffraction integral intensity I {311} from the {311} crystal plane satisfies (I {220} + I {311}) / I {200} . As a result, dimensional stability after pressing can be improved. It is considered that this is due to the fact that the slip system of the material differs depending on the crystal orientation and affects the formation of the wave front at the time of press working, but is not limited to this theory.

For this reason, the value of (I {220} + I {311}) / I {200} is preferably 5.0 or more, and more preferably 6.0 or more. Particularly, the upper limit is not formed, but it is preferably less than 10.0.

In the present invention, it is preferable that the X-ray diffraction integral intensity I {200} from the {200} crystal plane at the surface and the X-ray diffraction integral intensity Io {200} Lt; = 1.0. This is because if the intensity of I {200} / Io {200} is high, the pressability deteriorates. It is considered that the {200} crystal plane is more deformable than other orientations, so that the crystal grains including {200} crystal planes are preferentially deformed at the time of pressing, so that the pressability of the polycrystalline copper alloy is deteriorated.

On the other hand, if the ratio of I {200} / Io {200} is too small, there is a possibility that the non-recrystallization occurs in a part of the metal structure and the pressability deteriorates.

Therefore, the ratio of I {200} / Io {200} is preferably 0.1 or more and 1.0 or less, and more preferably 0.2 or more and 0.7 or less.

The X-ray diffraction integral intensity can be measured by using a predetermined X-ray diffraction apparatus.

(Manufacturing method)

The Cu-Co-Si based alloy as described above can be produced by a process of melting and casting an ingot, a hot rolling step, a first cold rolling step, a first solution treatment step, a second cold rolling step, A treatment step, an aging treatment step of heating the material at a temperature of 450 ° C to 550 ° C, and a final cold rolling step. Further, after hot rolling, it is possible to carry out machining as required.

Specifically, first, raw materials such as electric copper, Co, and Si are dissolved by using an atmospheric melting furnace or the like to obtain a molten metal having a desired composition. Then, the molten metal is cast into an ingot. Thereafter, hot rolling is carried out to perform the first cold rolling, the first solution treatment, the second cold rolling, the second solution treatment, the aging treatment (450 to 550 ° C for 2 to 20 hours), the final cold rolling 5 to 50%). After the final cold rolling, twist calibration annealing may be performed. Torsionally corrective annealing is usually carried out at 250 to 600 ° C for 5 to 300 seconds in an inert atmosphere such as Ar. After the second solution treatment, the final cold rolling and the aging treatment are performed in this order, and the order of these steps may be changed.

Here, in this manufacturing method, it is important to perform the first solution treatment, the second cold rolling and the second solution treatment under predetermined conditions after the first cold rolling. In the prior art, since the solution treatment was carried out once after the hot rolling without performing these steps, crystal grains as in the present invention could not be obtained and the dimensional stability after pressing could not be significantly improved.

Hereinafter, the respective processes of the first solution treatment, the second cold rolling and the second solution treatment will be mainly described. Further, the other processes can be conditions that are generally adopted in the process of manufacturing a Cu-Co-Si-based alloy.

The first solution treatment is performed at a material temperature of 900 to 1000 占 폚. As a result, Co, Si and, if necessary, Ni are solidified, and the crystal grains after the second solution treatment are refined to a predetermined size, and at the same time, the crystal orientation can be controlled as described above. When the temperature is lower than 900 占 폚, the solidification is coarse because the above-mentioned solidification does not proceed, and when the temperature exceeds 1000 占 폚, solidification proceeds too much to make control of the crystal orientation difficult.

In general, the aggregate structure of the copper alloy has a high solubility for the first time because the amount of the solution and the state of precipitation before the final solution are influenced. Also, the first solution treatment can be performed for 15 seconds to 300 seconds. If this time is too long, the balance between the solid solution and the precipitation will deteriorate to make it difficult to control the aggregate structure. If the time is too short, the solid solution will not proceed and the crystal grains will coarsen.

The second cold rolling after the first solution treatment is also carried out for finer crystal grains and crystal orientation control. For this purpose, the processing degree of the second cold rolling is set to 30 to 60%. If the degree of processing is less than 30%, coarsening of the crystal grains is caused. On the other hand, if the degree of processing exceeds 60%, the crystal orientation may not satisfy the above requirements.

Furthermore, it is preferable that the arithmetic mean roughness (Ra) of the surface of the material after the second cold-rolling is less than 0.2 탆 from the viewpoint of the improvement of the strength in the direction perpendicular to the rolling direction and the improvement of the dimensional accuracy after pressing. This is because the arithmetic mean roughness (Ra) of the surface of the material after the second cold rolling is controlled in this manner, whereby the 0.2% proof stress in the direction perpendicular to the rolling direction in the finished rolling is improved and the pressability is improved. This is because the embrittlement of the surface roughness changes the emissivity of the material and does not appear in (I {220} + I {311}) / I {200}, but the balance of texture after the second solution is optimized, It is conceivable that the 0.2% proof stress in the direction perpendicular to the rolling direction is improved and the pressability is improved. However, the present invention is not limited to this theory.

The arithmetic mean roughness (Ra) is the roughness of the surface of the material after the second cold rolling obtained based on JIS B0601 (2001). In order to realize such surface roughness Ra, the roll surface of the second cold rolling can be improved.

After the second cold rolling, a second solution treatment is performed. The second solution treatment can be carried out at a material temperature of 850 ° C to 1000 ° C. If the temperature is lower than 850 ° C, the strength is lowered due to insufficient solution formation. If the temperature is higher than 1000 ° C, the recrystallized grains grow and the crystal grains become larger.

And the second solution treatment time may be 15 seconds to 60 seconds. If the second solution treatment time is too long, the recrystallized grains will grow and the crystal grains will become larger and the pressability will deteriorate. If the second solution treatment time is too short, there is a possibility that the non-recrystallization will occur in a part of the metal structure.

When the aging treatment temperature is lower than 450 캜, the conductivity is lowered. When the aging treatment temperature is higher than 550 캜, the strength is lowered, and therefore, it is preferably set to 450 to 550 캜. In addition, since the required degree of workability of the final cold rolling is too low, the required strength can not be obtained. Therefore, the final cold rolling is preferably 5% or more, and the preferred upper limit is not particularly limited, but it may be generally 50% or less in order to prevent deterioration in bendability .

The Cu-Co-Si-based alloy of the present invention can be processed into various novel products, such as plates, rods, pipes, rods and wires. , Terminals, relays, switches, foil materials for secondary batteries, and the like. Particularly, high dimensional accuracy can be obtained by pressing at the time of manufacturing a connector.

Example

Next, a copper alloy for an electronic material of the present invention is prepared and tested for its performance. It is to be understood, however, that the description herein is for illustrative purposes only and is not intended to be limiting.

A copper alloy having the composition shown in Table 1 was melted at 1300 占 폚 using a high-frequency melting furnace and cast with an ingot having a thickness of 30 mm. Subsequently, the ingot was heated at 1000 占 폚 for 2 hours, then hot rolled to a plate thickness of 10 mm, and the hot rolling end temperature was set to 900 占 폚. After completion of the hot rolling, the material was cooled in water at an average cooling rate of 18 deg. C / s at the time of lowering until the material temperature reached 850 deg. C to 400 deg. C, and then cooled in water. After the surface was cut to a thickness of 9 mm to remove the scale, a plate having a thickness of 0.15 mm was formed by cold rolling. Thereafter, under the conditions shown in Table 1, the first solution treatment, the second cold rolling, the second solution treatment and the aging treatment were successively carried out to prepare test pieces.

Each of the test pieces thus obtained was subjected to the following characteristic evaluations. The results are shown in Table 2.

<Intensity>

Each test piece was subjected to tensile tests in the directions parallel to the rolling direction and in the direction perpendicular to the rolling direction based on JIS Z2241, and the 0.2% proof stress (YS: MPa) was measured and the difference in the 0.2% proof stress was calculated.

<Conductivity>

Conductivity (EC:% IACS) was determined by measuring the volume resistivity by a double bridge in accordance with JIS H0505.

&Lt; Average crystal grain diameter &

The average crystal grain diameter was determined by the cutting method (JIS H0501) by chemically etching the cross section parallel to the rolling direction after mirror surface polishing.

&Lt; Crystal orientation >

For each test piece, the diffraction intensity curve of the surface was obtained under the following measurement conditions by using an X-ray diffractometer of RINT2500 manufactured by Rigaku Corporation and the intensity intensities of the {200} crystal planes, the {220} crystal planes, and the {311} I) was measured to calculate (I {220} + I {311}) / I {200}. In addition, I {200} / I0 {200} was calculated by measuring the integral intensity (I) of the {200} crystal plane under the same measurement conditions for the pure powder sample.

· Target: Co conduit (tube)

· Tube voltage: 30kV

· Tube current: 100mA

Scanning speed: 5 ° / min

· Sampling width: 0.02 °

· Measuring range (2θ): 5 ° to 150 °

<Pressability>

A punch was displaced toward the die at a speed of 0.1 mm / min in a state where the die was placed between a square punch having a side of 10 mm and a die having a clearance of 0.01 mm. Pressing wave front after press was observed with an optical microscope to evaluate pressability by L / Lo when the width of the observation surface was Lo and the total length of the boundary between the front end face and the fractured end face was L as shown in Fig. The total length L was calculated from the photograph of the observation plane using the image analysis software. The width Lo of the observation plane is usually 5 mm or more, and the observation plane is the center portion in the width direction of the press wavefront.

In Table 2, "⊚" indicates that (1 <L / Lo ≤1.1), "∘" indicates 1.1 <L / L0 ≦ 1.3, and "×" indicates that (L / L0> 1.3) .

[Table 1]

[Table 2]

As shown in Tables 1 and 2, all of the inventive examples 1 to 20 were subjected to the first solution treatment, the second cold rolling, the second solution treatment, and the aging treatment under predetermined conditions, so that the 0.2% (I {220} + I {311}) / I {200}? 5.0, and the average crystal grain diameter in the rolling parallel cross section was 10 m or less. As a result, good pressability was obtained.

In Comparative Examples 1 to 8, the first solution treatment was not performed, the temperature of the first solution treatment was too high or too low, the degree of processing of the second cold rolling was out of a predetermined range, The crystal grains were coarsened or the crystal orientation did not satisfy the predetermined condition due to the fact that the surface roughness (Ra) after cold rolling was small or the temperature of the second solution treatment was too low.

In Comparative Example 9, the temperature of the second solution treatment was too high, so that the crystal grains became rough and the pressability deteriorated. In Comparative Example 10, the aging treatment temperature was low and the conductivity was low. In Comparative Example 11, the aging treatment temperature was high and the 0.2% proof stress was lowered. In Comparative Examples 12 and 13, the addition amount of Co or Si was large and the conductivity was low.

As described above, according to the present invention, it has been found that the dimensional stability when pressed into a connector shape or the like can be improved while having 0.2% proof stress and conductivity suitable for use in electronic materials.

Claims (6)

0.5 to 3.0 mass% of Co, 0.1 to 1.0 mass% of Si, and the balance of Cu and unavoidable impurities, wherein the 0.2% proof stress in the rolling parallel direction is 500 MPa or more, the conductivity is 60% Ray diffraction integrated intensity I {200} from the {200} crystal planes on the surface and the X-ray diffraction integral intensity from the {220} crystal planes I {220} and the X-ray diffraction integral intensity I {311} from the {311} crystal plane satisfy a relationship of (I {220} + I {311}) / I {200} . The method according to claim 1,
Wherein the difference in 0.2% proof stress minus the 0.2% proof stress in the direction perpendicular to the rolling direction from the 0.2% proof stress in the parallel direction of rolling is 50 MPa or less. 3. The method according to claim 1 or 2,
The relationship of I {200} / Io {200}? 1.0 in the X-ray diffraction integral intensity I {200} from the {200} crystal face at the surface and the X-ray diffraction integral intensity Io {200} Satisfactory, copper alloy for electronic materials. 3. The method according to claim 1 or 2,
And further contains Cr in an amount of 0.5 mass% or less. 3. The method according to claim 1 or 2,
And further contains Ni in an amount of 2.0 mass% or less. 3. The method according to claim 1 or 2,
Zn, and Sn in an amount of not more than 1.0 mass%, Mg, P, Ca, and Mn in an amount of not more than 0.2 mass%, and the total of at least one element selected from Zn, Sn, Mg, P, By mass to 2.0% by mass or less.

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