KR20120054099A - Cu-ni-si-co copper alloy for electronic material and process for producing same - Google Patents

Abstract

Provided is a Cu—Ni—Si—Co-based alloy having mechanical and electrical properties desirable as the copper alloy for electronic materials and having uniform mechanical properties. Ni ： 1.0? 2.5 mass%, Co: 0.5? 2.5 mass%, Si: 0.3? It is a copper alloy for electronic materials containing 1.2 mass% and remainder consists of Cu and an unavoidable impurity, and whose average grain size is 15? The copper alloy for electronic materials which is 30 micrometers, and the average of the difference of the largest crystal grain size and the smallest crystal grain diameter every 0.5 mm <2> of observation visual fields is 10 micrometers or less.

Description

Cu-Ni-Si-CO-based copper alloys for electronic materials and manufacturing methods thereof {Cu-Ni-Si-Co COPPER ALLOY FOR ELECTRONIC MATERIAL AND PROCESS FOR PRODUCING SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to precipitation hardening copper alloys, and in particular, to Cu-Ni-Si-Co-based copper alloys suitable for use in various electronic device components.

Copper alloys for electronic materials used in various electronic device components such as connectors, switches, relays, pins, terminals, and lead frames are required to have both high strength and high conductivity (or thermal conductivity) as basic characteristics. In recent years, high integration, miniaturization, and thinning of electronic components have progressed rapidly, and correspondingly, demand levels for copper alloys used in electronic component parts have been further advanced.

In view of high strength and high electrical conductivity, the amount of precipitation hardening copper alloys is increasing instead of the solid solution strengthening copper alloys represented by conventional phosphor bronze, brass and the like as the copper alloy for electronic materials. In the precipitation hardening-type copper alloy, by aging the solution-treated supersaturated solid solution, fine precipitates are uniformly dispersed to increase the strength of the alloy and reduce the amount of solid solution in copper to improve electrical conductivity. For this reason, the material which is excellent in mechanical properties, such as strength and spring property, and is excellent in electrical conductivity and thermal conductivity is obtained.

Among the precipitation hardening copper alloys, Cu-Ni-Si-based copper alloys, which are generally called Coulson-based alloys, are representative copper alloys having relatively high conductivity, strength, and bending workability, and are one of the alloys currently being actively developed in the industry. . In this copper alloy, strength and electrical conductivity can be improved by depositing fine Ni-Si-based intermetallic compound particles in a copper matrix.

Attempts have been made to further improve the properties by adding Co to the Colson alloy.

In Japanese Unexamined Patent Publication No. 11-222641 (Patent Document 1), Co forms a compound with Si similarly to Ni to improve mechanical strength, and when Cu-Co-Si system is aged, Cu-Ni- Both mechanical strength and conductivity are slightly better than Si-based alloys. And it is described that you may select Cu-Co-Si type | system | group or Cu-Ni-Co-Si type | system | group if cost-acceptable. As a manufacturing method of the said alloy, recrystallization treatment after cold work is carried out 700- ?. It carries out at 920 degreeC, and is 25% or less of cold working next, 420? After performing the aging treatment at 550 ° C., a method of further cold working up to 25% and low temperature annealing is described (claim 10).

Japanese Laid-Open Patent Publication No. 2005-532477 (Patent Document 2) has a weight of nickel: 1%? 2.5%, cobalt 0.5? 2.0%, silicon: 0.5%? It consists of 1.5% and remainder copper and an unavoidable impurity, and the total content of nickel and cobalt is 1.7%? 4.3% and ratio (Ni + Co) / Si is 2: 1? The annealed copper alloy of 7: 1 is described, and the annealed copper alloy has electroconductivity exceeding 40% IACS. Cobalt is combined with silicon to form silicides effective for age hardening in order to limit particle growth and improve softening resistance. As a manufacturing method of the said alloy, it is 850 degreeC? Hot working at 1000 ℃ → 800 ℃? Solution treatment at 1000 ℃ → temperature 350 ℃? 600 ℃, 30 minutes? First aging annealing in 30 hours → 10%? A method of performing a second aging annealing carried out at a temperature lower than the first aging annealing temperature → cold working to reduce the cross-sectional area of 50% is described (claims 25 and 26).

In International Publication No. 2006/101172 pamphlet (Patent Document 3), in the solution treatment, if the cooling rate after heating is consciously increased, the effect of improving the strength of the Cu-Ni-Si-based alloy is further exerted. It is described that it is effective to cool to at least about 10 ° C. per second (paragraph 0028).

Japanese Laid-Open Patent Publication No. 9-20943 is subjected to cold rolling of 85% or more after hot rolling, to 450? At 480 ℃ 5? After annealing for 30 minutes, cold rolling of 30% or less is performed and further 450? 30 at 500 ℃? A method for producing a Cu-Ni-Si-Co based alloy which is subjected to aging treatment for 120 minutes is described (claim 5).

Japanese Patent Application Laid-Open No. 11-222641 Japanese Patent Publication No. 2005-532477 International Publication No. 2006/101172 Brochure Japanese Patent Laid-Open No. 9-20943

As described above, the addition of Co to the Cu-Ni-Si-based alloy is known to improve the strength and conductivity, but in the conventional Cu-Ni-Si-Co-based alloy, the strength and the stress may be reduced depending on the measurement point even with the same material. There existed a problem that a deviation tends to occur in mechanical characteristics, such as a characteristic and bending roughness.

Accordingly, one object of the present invention is to provide a Cu-Ni-Si-Co-based alloy having mechanical and electrical properties that are desirable as a copper alloy for electronic materials and having uniform mechanical properties. Another object of the present invention is to provide a method for producing such a Cu-Ni-Si-Co alloy.

First, the inventors found out that the Cu-Ni-Si-Co-based alloys have a large variation in the size of crystal grains, and that large particles and small particles are mixed, and the nonuniformity of the grain size leads to variations in mechanical properties. I found out. In the Cu-Ni-Si-Co alloy, it is necessary to perform the solution treatment at a higher temperature than the conventional Cu-Ni-Si alloy by adding Co, and recrystallization is likely to coarsen. On the other hand, second phase particles such as crystallized precipitates and precipitates precipitated at the front end of the solution treatment process become obstacles and inhibit the growth of crystal grains. Therefore, in the Cu-Ni-Si-Co-based alloy, the variation of recrystallized grains tends to be larger than that of the conventional Cu-Ni-Si-based alloy.

Therefore, as a result of earnestly examining the means for reducing the variation of the recrystallized grains, the present inventors have precipitated the fine second phase particles in the copper matrix phase as uniformly as possible at the front end of the solution treatment step, thereby solving the solution solution. Even when the reaction was carried out at a relatively high temperature, it was found that the grain size did not increase due to the pinning effect of the second phase particles, and that the size of the growing recrystallized grain could be equalized in that the pinning effect acted uniformly over the entire copper matrix phase. As a result, it was found that a Cu—Ni—Si—Co alloy having a small variation in mechanical properties was obtained.

Based on the above findings, the present invention has been completed in one aspect with Ni: 1.0? 2.5 mass%, Co: 0.5? 2.5 mass%, Si: 0.3? It is a copper alloy for electronic materials containing 1.2 mass% and remainder consists of Cu and an unavoidable impurity, and whose average grain size is 15? It is 30 micrometers and the copper alloy for electronic materials whose average of the difference of the largest crystal grain size and the minimum crystal grain diameter every 0.5 mm <2> of observation visual fields is 10 micrometers or less.

In one embodiment, the copper alloy which concerns on this invention contains Cr at most 0.5 mass% further.

In another embodiment, the copper alloy according to the present invention further contains at most 0.5 mass% of one kind or two or more kinds selected from Mg, Mn, Ag, and P in total.

In yet another embodiment, the copper alloy according to the present invention further contains up to 2.0% by mass in total of one or two species selected from Sn and Zn.

In yet another embodiment, the copper alloy according to the present invention further contains at most 2.0 mass% of one kind or two or more kinds selected from As, Sb, Be, B, Ti, Zr, Al, and Fe in total. .

In another aspect of the present invention,

? Process 1 which melt-casts an ingot having a desired composition, and

? 950 ℃? Hot rolling is performed after heating at 1050 degreeC for 1 hour or more, and the temperature at the time of completion | finish of hot rolling is made into 850 degreeC or more, and is 850 degreeC? Process 2 which cools by making average cooling rate to 400 degreeC into 15 degreeC / s or more,

? Cold rolling step 3 of 85% or more of workability,

? 350? 1 at 500 ℃? With the aging treatment process 4 to heat for 24 hours,

? 950 ℃? The solution treatment is performed at 1050 ° C, and the material temperature is 850 ° C. Process 5 which cools by making average cooling rate 15 degreeC / s or more when it falls to 400 degreeC,

? Voluntary cold rolling process 6,

? Aging treatment step 7,

? Voluntary cold rolling process 8,

? Deformation annealing process 9

It is a manufacturing method of the copper alloy containing performing in order.

In yet another aspect, the present invention is a flexible product provided with the copper alloy.

In yet another aspect, the present invention is an electronic device component including the copper alloy.

According to the present invention, since the crystal grain size is uniform in an appropriate range, a Cu-Ni-Si-Co-based alloy with uniform mechanical properties is obtained.

1 is an explanatory diagram of a stress relaxation test method.
It is explanatory drawing about the permanent deformation amount of a stress relaxation test method.

Ni , Co  And Of Si  Addition amount

Ni, Co, and Si can form an intermetallic compound by performing appropriate heat processing, and can attain high strength, without degrading electrical conductivity.

If the addition amounts of Ni, Co, and Si are less than Ni: 1.0 mass%, Co: less than 0.5 mass%, and Si: less than 0.3 mass%, the desired strength cannot be obtained. Conversely, Ni: 2.5 mass% and Co: 2.5 mass% If the Si content exceeds 1.2% by mass, the high strength can be achieved, but the electrical conductivity is significantly lowered, and thus the hot workability is deteriorated. Therefore, the addition amount of Ni, Co, and Si is Ni: 1.0? 2.5 mass%, Co: 0.5? 2.5 mass%, Si: 0.3? It was 1.2 mass%. The addition amounts of Ni, Co and Si are preferably Ni: 1.5? 2.0 mass%, Co: 0.5? 2.0 mass%, Si: 0.5? 1.0 mass%.

Of Cr  Addition amount

Since Cr is first precipitated at the grain boundaries in the cooling process during melt casting, the grain boundaries can be strengthened, so that cracks during hot working are less likely to occur, and the yield decrease can be suppressed. In other words, Cr precipitated at the time of melt casting is re-used by solution treatment or the like, but during subsequent age precipitation, Cr forms precipitated particles having a main component of Cr or a compound with Si. In conventional Cu-Ni-Si-based alloys, Si, which does not contribute to aging precipitation, suppresses the increase in conductivity while being dissolved in the mother phase, but precipitates further silicide by adding Cr, a silicide forming element. By doing so, the amount of solid solution Si can be reduced, and the electrical conductivity can be increased without inhibiting the strength. However, when Cr concentration exceeds 0.5 mass%, it becomes easy to form coarse 2nd phase particle | grains, and it inhibits product characteristics. Therefore, 0.5 mass% of Cr can be added to the Cu-Ni-Si-Co type alloy which concerns on this invention at the maximum. However, since the effect is small when it is less than 0.03 mass%, Preferably it is 0.03? 0.5 mass%, More preferably, it is 0.09? It is preferable to add 0.3 mass%.

Mg , Mn , Ag  And P  Addition amount

Mg, Mn, Ag, and P improve product characteristics, such as strength and stress relaxation characteristics, without impairing electrical conductivity by addition of a trace amount. Although the effect of the addition is mainly exerted by the solid solution to the mother phase, the effect may be further exerted by being contained in the second phase particles. However, when the total of concentrations of Mg, Mn, Ag, and P exceeds 0.5%, the characteristic improvement effect is saturated, and the manufacturability is inhibited. Therefore, in the Cu-Ni-Si-Co-based alloy according to the present invention, one or two or more kinds selected from Mg, Mn, Ag, and P can be added up to 0.5 mass% in total. However, since the effect is small when it is less than 0.01 mass%, Preferably it is 0.01? 0.5 mass%, More preferably, it is 0.04? It is preferable to add 0.2 mass%.

Sn  And Of Zn  Addition amount

Also in Sn and Zn, product characteristics, such as strength, stress relaxation characteristics, and plating property, are improved, without impairing electrical conductivity by addition of a trace amount. The effect of the addition is mainly exerted by the solid solution to the mother phase. However, when the total amount of Sn and Zn exceeds 2.0 mass%, the characteristic improvement effect is saturated, and the manufacturability is inhibited. Therefore, up to 2.0 mass% of 1 type or 2 types selected from Sn and Zn can be added to Cu-Ni-Si-Co type alloy which concerns on this invention in total. However, since the effect is small when it is less than 0.05 mass%, Preferably it is 0.05? 2.0 mass%, More preferably, it is 0.5? It is preferable to add 1.0 mass%.

As , Sb , Be , B, Ti , Zr , Al  And Fe

Also in As, Sb, Be, B, Ti, Zr, Al and Fe, by adjusting the addition amount in accordance with the required product properties, product properties such as electrical conductivity, strength, stress relaxation characteristics, plating properties and the like are improved. The effect of the addition is mainly exerted by the solid solution to the mother phase, but may also be more effective by forming the second phase particles contained in the second phase particles or by forming a new composition. However, when the total of these elements exceeds 2.0 mass%, the characteristic improvement effect will be saturated, and manufacturability will be inhibited. Therefore, the Cu-Ni-Si-Co-based alloy according to the present invention may be added at most 2.0 mass% of one or two or more selected from As, Sb, Be, B, Ti, Zr, Al, and Fe in total. Can be. However, since the effect is small when it is less than 0.001 mass%, Preferably it is 0.001? 2.0 mass%, More preferably, it is 0.05? It is preferable to add 1.0 mass%.

When the addition amount of the above-mentioned Mg, Mn, Ag, P, Sn, Zn, As, Sb, Be, B, Ti, Zr, Al and Fe exceeds 3.0% in total, since it is easy to inhibit manufacturability, Preferably these The sum total is 2.0 mass% or less, and more preferably 1.5 mass% or less.

Grain size

Grain grains affect the strength, and the Hall-Petch rule generally holds that the strength is proportional to the -1/2 power of the grain size. Moreover, coarse crystal grains deteriorate bending workability and become a factor of surface roughness at the time of bending work. Therefore, in a copper alloy, it is generally preferable to refine a crystal grain in order to improve strength. Specifically, the thickness is preferably 30 µm or less, and more preferably 23 µm or less.

On the other hand, since the Cu-Ni-Si-Co-based alloy like the present invention is a precipitation strengthening alloy, it is also necessary to pay attention to the precipitation state of the second phase particles. In the aging treatment, the second phase particles precipitated in the grains contribute to the improvement of the strength, but the second phase particles precipitated at the grain boundary contribute little to the improvement of the strength. Therefore, in order to improve the strength, it is preferable to precipitate the second phase particles in the crystal grains. When the grain size decreases, the grain boundary area becomes large, and therefore, the second phase particles tend to preferentially precipitate at the grain boundary during the aging treatment. In order to precipitate the second phase particles in the crystal grains, the crystal grains need a certain size. Specifically, the thickness is preferably 15 µm or more, more preferably 18 µm or more.

In the present invention, the average grain size is 15? It is controlled in the range of 30 micrometers. The average grain size is preferably 18? 23 μm. By controlling the average grain size in such a range, it is possible to balance both the strength improving effect due to grain refinement and the strength improving effect due to precipitation hardening. Moreover, if it is the crystal grain diameter of the said range, it is possible to obtain the outstanding bending workability and a stress relaxation characteristic.

In the present invention, the crystal grain size refers to the diameter of the minimum circle surrounding individual grains when the cross section in the thickness direction parallel to the rolling direction is observed under a microscope, and the average grain size is the average value.

In the present invention, the average of the difference between the maximum grain size and the minimum grain size per 0.5 mm 2 observation field is 10 µm or less, preferably 7 µm or less. Since the average of the difference is ideally 0 占 퐉, but practically difficult, the lower limit is set to the lowest value of the reality of 3 占 퐉, and typically 3? 7 μm is optimal. Here, the maximum grain size is the maximum grain size observed in one observation field of 0.5 mm 2, and the minimum grain size is the minimum grain size observed in the same field of view. In the present invention, the difference between the maximum grain size and the minimum grain size is determined for each of the plurality of observation fields, and the average value is taken as the average of the difference between the maximum grain size and the minimum grain size.

The small difference between the largest grain size and the smallest grain size indicates that the size of the grain size is uniform, which alleviates the variation in mechanical properties for each measuring point in the same material. As a result, the quality stability of new products or electronic device parts obtained by processing the copper alloy according to the present invention is improved.

Manufacturing method

In the general manufacturing process of a Colson-type copper alloy, first, raw materials, such as electric copper, Ni, Si, Co, etc., are melt | dissolved using an atmospheric melting furnace, and the molten metal of a desired composition is obtained. And this molten metal is cast into an ingot. Then, hot rolling is performed, cold rolling and heat processing are repeated, and it finishes with the strip or foil which has a desired thickness and characteristic. Heat treatment includes a solution treatment and an aging treatment. In the solution treatment, about 700? By heating at a high temperature of about 1000 ° C., the second phase particles are solid-dissolved in the Cu matrix, and at the same time, the Cu matrix is recrystallized. The solution treatment may also serve as hot rolling. In aging treatment, around 350? It heats over 1 hour in the temperature range of about 550 degreeC, and the 2nd phase particle solid-dissolved by the solution treatment precipitates as fine particle of a nanometer order. This aging treatment increases strength and electrical conductivity. In order to obtain higher strength, cold rolling may be performed before and / or after aging. Moreover, when cold rolling is performed after aging, strain removal annealing (low temperature annealing) may be performed after cold rolling.

Grinding, polishing, shot blast pickling and the like for appropriately removing the surface oxide scale are appropriately performed between the above steps.

Also in the copper alloy according to the present invention, although the above-described manufacturing process is basically performed, in order to control the variation of the average crystal grain size and the crystal grain diameter within the range defined by the present invention, as described above, It is important to deposit the fine second phase particles at the front end as uniformly as possible at regular intervals in the copper matrix. In order to obtain the copper alloy which concerns on this invention, it is necessary to manufacture especially paying attention to the following points.

First, since coarse crystals are inevitably generated in the solidification process during casting, and coarse precipitates are inevitably generated in the cooling process, it is necessary to employ these crystals in the mother phase in a subsequent process. 950 ℃? If hot rolling is performed after holding at 1050 degreeC for 1 hour or more, and the temperature at the time of completion | finish of hot rolling is set to 850 degreeC or more, even if Co and further Cr are added, it can solid-solution in a mother phase. The temperature condition of 950 ° C. or higher is a high temperature setting as compared with the case of other Colson-based alloys. When the holding temperature before hot rolling is less than 950 degreeC, solid solution is inadequate, and when it exceeds 1050 degreeC, there exists a possibility that a material may melt | dissolve. In addition, when the temperature at the end of hot rolling is less than 850 ° C, the dissolved element precipitates again, which makes it difficult to obtain high strength. Therefore, in order to obtain high strength, it is preferable to finish hot rolling at 850 degreeC, and to cool rapidly.

At this time, if the cooling rate is slow, Si-based compounds containing Co or Cr are precipitated again. When performing heat treatment (aging treatment) for the purpose of increasing the strength in such a structure, high strength cannot be obtained because it grows into coarse precipitate which does not contribute to the strength by using the precipitate precipitated in the cooling process as a nucleus. Therefore, it is necessary to make cooling rate as high as possible, and to be 15 degreeC / s or more specifically. However, since the precipitation of a 2nd phase particle is remarkable to about 400 degreeC, the cooling rate below 400 degreeC does not become a problem. Therefore, in this invention, material temperature is 850 degreeC? The average cooling rate up to 400 degreeC is made into 15 degreeC / s or more, Preferably it is 20 degreeC / or more, and is made to cool. "Average cooling rate when it falls to 850 degreeC-400 degreeC" means that material temperature is 850 degreeC? The cooling time falling to 650 degreeC is measured, and the value (degreeC / s) calculated by "(850-400) (degreeC) / cooling time (s)" is said.

Water cooling is the most effective way to speed up cooling. However, since a cooling rate changes with the temperature of the water used for water cooling, cooling can be made faster by water temperature management. Since the desired cooling rate may not be obtained if the water temperature is 25 ° C or higher, it is preferable to maintain the temperature at 25 ° C or lower. When the material is put into a tank where water is collected and cooled, the temperature of the water is easily increased to 25 ° C. or higher, so that the material is sprayed in a fog phase (shower or mist phase) to cool the material at a constant water temperature (25 ° C. or lower). For example, it is desirable to always keep cold water flowing in the water tank to prevent the temperature rise. In addition, the cooling rate can also be increased by expanding the water cooling nozzle or increasing the amount of water per unit time.

After hot rolling, cold rolling is performed. This cold rolling is performed for the purpose of increasing the deformation which becomes a precipitation site, in order to deposit a precipitate uniformly, It is preferable to perform cold rolling at 85% or more of reduction ratio, and to carry out by 95% or more of reduction ratio. desirable. If the solution is subjected to the solution treatment immediately after the hot rolling without cold rolling, the precipitates do not precipitate uniformly. The combination of hot rolling and subsequent cold rolling may be repeated suitably.

After cold rolling, the first aging treatment is performed. If the second phase particles remain before the present step, such second phase particles grow further when the present step is carried out, so that a difference occurs in the particle size and the second phase particles precipitated for the first time in this step. In this invention, however, since the second phase particles are almost extinct in the step of shearing, the fine second phase particles can be uniformly precipitated in a uniform size.

However, if the aging temperature of the first aging treatment is too low, the amount of precipitation of the second phase particles that brings about the pinning effect is small, and only a part of the pinning effect generated by the solution treatment is obtained, so that the grain size is increased. Non-uniform On the other hand, when the aging temperature is too high, the second phase particles become coarse, and the second phase particles precipitate unevenly, so that the size of the particle size of the second phase particles becomes uneven. In addition, since the second phase particles grow as the aging time is longer, it is necessary to set the appropriate aging time.

The first aging treatment is 350? 1 at 500 ℃? 24 hours, Preferably it is 12 to 350 degreeC or more and less than 400 degreeC. 6 hours at 400 ℃ or more and less than 450 ℃ for 24 hours. 12 hours, 450 ℃ or more and less than 500 ℃ 3? By carrying out for 6 hours, the fine second phase particles can be uniformly precipitated in the mother phase. With such a structure, the growth of recrystallized grains generated by the solution treatment in the next step can be pinned constantly, and a grain structure with less variation in grain size can be obtained.

After the first aging treatment, a solution treatment is performed. Here, fine and uniform recrystallized grains are grown while solidifying the second phase particles. Therefore, solution temperature is 950 degreeC? It is necessary to set it as 1050 degreeC. Here, the recrystallized grains first grow, and after that, the second phase particles precipitated by the first aging treatment are dissolved, whereby the growth of the recrystallized grains can be controlled by the pinning effect. However, since the pinning effect is lost after the second phase particles are dissolved, recrystallization grains increase when the solution treatment is continued for a long time. So, the time for proper solution treatment is 60 seconds at 950 ° C or more and less than 1000 ° C. 300 seconds, preferably 120? It is 180 seconds and is 30 seconds when it is more than 1000 degreeC and less than 1050 degreeC. 180 seconds, preferably 60 seconds? 120 seconds.

Also in the cooling process after solution treatment, in order to avoid precipitation of a 2nd phase particle | grain, material temperature is 850 degreeC? The average cooling rate at the time of falling to 400 degreeC should be 15 degreeC / s or more, Preferably it should be 20 degreeC / s or more.

After the solution treatment, a second aging treatment is performed. The conditions of the second aging treatment may be any conditions that are conventionally performed because they are useful for miniaturization of precipitates, but care should be taken to set the temperature and time so that the precipitates do not coarsen. As an example of the conditions of the aging treatment, 350? 1? In the temperature range of 550 ℃? 24 hours, More preferably, 400? 1? In the temperature range of 500 ℃? 24 hours. In addition, the cooling rate after aging treatment hardly affects the magnitude of the precipitate. In the case of before 2nd aging, a precipitation site is extended, aging hardening is accelerated | stimulated using a precipitation site, and intensity | strength increase is aimed at. In the case after the second aging, work hardening is promoted by using a precipitate to increase the strength. Cold rolling may be performed before and / or after the second aging treatment. After cold rolling after the second aging treatment, strain removal annealing is performed to improve stress relaxation characteristics. Strain removal annealing may be conventional heating conditions, for example annealing temperature 250 ℃? At 400 ℃ 1? 24 hours, preferably 250 ° C. At 350 ℃ 1? Conduct 24 hours.

The Cu-Ni-Si-Co-based alloy of the present invention can be processed into various new products such as plates, strips, tubes, rods and wires, and the Cu-Ni-Si-Co-based copper alloy according to the present invention. Silver can be used for electronic components such as lead frames, connectors, pins, terminals, relays, switches, and secondary battery foils.

Example

Although the Example of this invention is shown with a comparative example below, these Examples are provided in order to understand this invention and its advantage better, and it does not intend that invention is limited.

The copper alloy of the component composition of Table 1 (Example) and Table 2 (comparative example) was melted at 1300 degreeC with the high frequency melting furnace, and was cast in the ingot of thickness 30mm. Subsequently, after heating this ingot to 1000 degreeC, it hot-rolled to 10 mm of plate | board thickness, and it was 900 degreeC of finishing temperature (hot rolling end temperature). After the end of hot rolling, the material temperature is 850 ℃? The average cooling rate at the time of falling to 400 degreeC was set to 18 degreeC, and water cooled, and it was left to cool in air after that, and it cooled. Subsequently, in order to remove the scale of a surface, it surface-treated to 9 mm in thickness, and was made into the board of thickness 0.15 mm by cold rolling. Subsequently, the first aging treatment was carried out at 3? After performing for 12 hours, the solution treatment was performed for 120 seconds at various solution temperatures, and immediately afterwards, the material temperature was 850 占 폚. The average cooling rate at the time of falling to 400 degreeC was set to 18 degreeC, and water cooled, and it was left to cool in air after that, and it cooled. Subsequently, cold rolling was performed to 0.10 mm, the second aging treatment was performed at 450 ° C. for 3 hours in an inert atmosphere, and further cold rolled to 0.08 mm, and finally at 300 ° C. for 3 hours in an inert atmosphere. Deformation annealing was performed to prepare a test piece.

Thus, various characteristics evaluation was performed about each test piece obtained as follows.

(1) average crystal grain size

The crystal grain size is a resin embedded in the sample so that the observation surface becomes a cross section in the thickness direction parallel to the rolling direction, and after the mirror surface finish by mechanical polishing, the ratio of 10 vol. Parts of hydrochloric acid with a concentration of 36% to 100 parts by volume of water. Ferric chloride of 5% by weight of the solution weight was dissolved in the solution mixed with. In this way, the sample was immersed in the completed solution for 10 seconds to reveal the metal structure. Next, the metal structure was magnified 100 times with an optical microscope, and the observation field of 0.5 mm 2 was taken on one photograph to obtain all the diameters of the minimum circle surrounding the individual grains, and the average value was calculated for each observation field. The average value of 15 points | pieces was made into the average crystal grain size.

(2) Average of difference between maximum grain size-minimum grain size

When the average crystal grain size was obtained, the difference between the maximum value and the minimum value was determined for each field of view with respect to the crystal grain diameter measured, and the average value of 15 observation fields was taken as the average of the difference between the maximum grain size and the minimum grain size.

(3) strength

About strength, the tensile test of the rolling parallel direction was done, and 0.2% yield strength (YS: MPa) was measured. The variation in the intensity by the measuring point is assumed to be the difference between the maximum intensity and the minimum intensity at 30 points, and the average intensity is the average value at these 30 points.

(4) conductivity

About electrical conductivity (EC;% IACS), it calculated | required by the volume resistivity measurement by double bridge. The deviation of the electrical conductivity by the measurement point is assumed to be the difference between the maximum strength and the minimum strength at 30 points, and the average conductivity is the average value at these 30 points.

(5) stress relaxation characteristics

As for the stress relaxation characteristic, as shown in FIG. 1, the target point distance (l) is 25 mm, and the height (y ₀ ) of the load stress is 0.2 for each test piece whose thickness (t) = 0.08 mm processed to width 10mm x length 100mm. The height was determined so as to be 80% of the% yield strength, the bending stress was loaded, the permanent deformation amount (height) (y) shown in FIG. ₁ ) (mm) / (y ₀ -y ₁ ) (mm)] × 100 (%) 'was calculated. In addition, y ₁ is the height of initial bending before loading a stress. The variation of the stress relaxation rate by the measuring point is assumed to be the difference between the maximum strength and the minimum strength of 30 points, and the average stress relaxation rate is the average value of these 30 points.

(6) bending workability

Bending workability was evaluated by surface roughness of a bending part. According to JIS H 3130, the W bending test of Badway (bending axis is the same direction as the rolling direction) was performed, the surface of the bending part was analyzed with a confocal laser microscope, and Ra (µm) of JIS B 0601 specification was obtained. The deviation of the bending roughness by the measurement point is assumed to be the difference between the maximum Ra-minimum Ra of 30 points, and the average bending roughness is the average value of Ra of these 30 points.

[Table 1-1]

TABLE 1-2

TABLE 2

No.1? The alloy of 34 is an embodiment of the present invention, has strength and conductivity suitable for use in electronic materials, and has a small variation in properties.

No.35? 37, 46? In the alloy of 48, the first aging treatment was not performed, and the crystal grain size was coarsened during the solution treatment to deteriorate the strength and the bending workability.

In the alloys of Nos. 38, 39, 42, 44, 49, and 50, the aging temperature of the first aging treatment was too low and the second phase particles were small. Bending workability deteriorated. Moreover, the variation of the crystal grain size increased. As a result, the variation of characteristics became large.

No.40, 41, 43, 45, 51? In the alloy of 54, the aging temperature of the first aging treatment was too high, and because the second phase particles grew unevenly, the grain size of the alloy was uneven. As a result, the variation of characteristics became large.

Nos. 55 and 56 had excessively high amounts of Co, so the strength and the electrical conductivity were deteriorated.

No.57? 60 was not subjected to the first aging treatment and had a low solution temperature. Since the second phase particles were not sufficiently dissolved and the crystal grains were too small, the strength and the stress relaxation characteristics deteriorated.

Claims (8)

Ni ： 1.0? 2.5 mass%, Co: 0.5? 2.5 mass%, Si: 0.3? It is a copper alloy for electronic materials containing 1.2 mass% and remainder consists of Cu and an unavoidable impurity, and whose average grain size is 15? The copper alloy for electronic materials which is 30 micrometers, and the average of the difference of the largest crystal grain size and the smallest crystal grain diameter every 0.5 mm <2> of observation visual fields is 10 micrometers or less. The method of claim 1,
Furthermore, the copper alloy for electronic materials containing Cr at most 0.5 mass%. The method according to claim 1 or 2,
Furthermore, the copper alloy for electronic materials which contains a maximum of 0.5 mass% of 1 type, or 2 or more types selected from Mg, Mn, Ag, and P in total. The method according to any one of claims 1 to 3,
Furthermore, the copper alloy for electronic materials containing a maximum of 2.0 mass% of 1 type or 2 types selected from Sn and Zn. The method according to any one of claims 1 to 4,
Furthermore, copper alloy for electronic materials containing a maximum of 2.0 mass% of 1 type, or 2 or more types selected from As, Sb, Be, B, Ti, Zr, Al, and Fe in total. ? Process 1 which melt-casts an ingot having a desired composition, and
? 950 ℃? Hot rolling is performed after heating at 1050 degreeC for 1 hour or more, and the temperature at the time of completion | finish of hot rolling is made into 850 degreeC or more, and is 850 degreeC? Process 2 which cools by making average cooling rate to 400 degreeC into 15 degreeC / s or more,
? Cold rolling step 3 of 85% or more of workability,
? 350? 1 at 500 ℃? With the aging treatment process 4 to heat for 24 hours,
? 950 ℃? The solution treatment is performed at 1050 ° C, and the material temperature is 850 ° C. Process 5 which cools by making average cooling rate 15 degreeC / s or more when it falls to 400 degreeC,
? Voluntary cold rolling process 6,
? Aging treatment step 7,
? Voluntary cold rolling process 8,
? Deformation annealing process 9
The manufacturing method of the copper alloy in any one of Claims 1-5 which implements in order. The new product provided with the copper alloy in any one of Claims 1-5. The electronic device component provided with the copper alloy in any one of Claims 1-5.

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