TW200837203A - Cu-Ni-Si-based copper alloy for electronic material - Google Patents

Abstract

To provide a Corson alloy in which characteristics are dramatically improved by bringing out the better effect of Cr addition. This copper alloy for electronic material has a composition which is composed of, by mass, 2.5 to 4.5% Ni, 0.50 to 1.2% Si, 0.0030 to 0.2% Cr and the balance Cu with inevitable impurities and in which the weight ratio between Ni and Si satisfies 3 ≤ Ni/Si ≤ 7. Further, the amount of carbon is made ≤ 50 mass ppm.

Description

[Technical Field] The present invention relates to a precipitation hardening type copper alloy, and more particularly to a Cu-Ni-Si type copper alloy which is suitable for various electronic machine parts. [Prior Art] Thousands; wire wood connection, pin, terminal, relay, switch, etc. The electronic material used in the bun machine parts, the species Sun & seven η 士 a Meng ' as the basic characteristics:, to: the same as w Strength and high electrical conductivity (or thermal conductivity). In recent years, the Xunzi order has been accumulating and miniaturized, and the steel fit used for electronic machine parts is === relative to high. In view of the high strength and high conductivity of fish, in recent years, the use amount of precipitation hardened copper alloy has been gradually increased to replace the solid solution-enhanced copper alloy in the past with bronze and table. It is specially designed for the generation of hard copper alloys. It is a two-effect treatment of the supersaturated solid solution after solution treatment. In this way, the fine precipitates are uniformly dispersed. Copper: The amount of solid solution elements is reduced, and the conductivity is improved. . Therefore, it is excellent in mechanical properties such as strength and elasticity. ♦Cu-Ni which is a good thermal property in the precipitation hardening type copper alloy, which is called the Corson series, is a high-conductivity, two-stress The representative copper-binding boundary of the mitigating property and the processing property is a person who is enthusiastically developing. The fine-grained metal bismuth of the present industry = the particles of the mouth are deposited in the copper base material, and the strength and electrical conductivity are improved by the method of 2008.

The precipitate of the Ni-Si-based intermetallic compound particles is generally composed of a stoichiometric composition, and is described, for example, in Japanese Laid-Open Patent Publication No. Hei. No. Hei. The mass composition ratio of Ni2Si of the intermetallic compound (the atomic weight of Ni is an atomic weight of &, that is, by making the weight concentration ratio of N! and Si to Ni/Si = 3 to 7, good conductivity can be obtained. Further, in the Cn-Ni-S! series alloy, there is also a case of adding & as an alloying element. A heat treatment method of a Corson alloy is described in Japanese Patent No. 2,629,942, which is characterized in that heating (or cooling) is performed by Ni: 1·5 to 4·0% by mass, Si: 〇.35 to 1% by mass, optionally selected from 汾,

When at least one metal of the group consisting of Cr and Sl1 is 科.〇5~丨〇% by mass, and the rest is a Corson alloy composed of Cu and unavoidable impurities, in the '------ Heating (or cooling) the Corson alloy to increase the tensile thermal strain of the Corson alloy to ixio-4 or less. According to this method, the ingot may be cracked during the heat treatment. In the 公报 公报 , , , : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : Cr: 0.001 ~ Μ Mass %, A1: 0 001 ~ 〇 15 Berry %, C 〇: 0.05 〜 2% by mass 'The content of the impurity component s is limited to 15 ppm u, and the rest is Cu and unavoidable impurities. According to the invention, it is considered that Cr is a grain boundary which can strengthen the prayer block, and the element 1 which improves the hot workability, if it contains more than 5% by mass, oxidizes the molten solution, and 200837203 causes deterioration of castability. It is stated that the copper alloy is melted in a Kraft (four) pt〇i furnace under atmospheric charcoal coating. [Patent Document 1] JP-A-2001-207229 [Patent Document 2] Japanese Patent No. 2,829,942 [Patent Document 3] Japanese Patent No. 3,497,137 [Summary of the Invention] In the weight-to-concentration ratio of 2001-207229, although it is possible to improve the characteristics while controlling Ni/Si = 3 to 7, it is difficult to maintain high strength while maintaining a high electrical conductivity. Although high strength can be obtained, it will result in a decrease in electrical conductivity. Further, hot workability is also impaired, and the yield is lowered, so that it is economical. Therefore, even if the amount of Ni-S^ is adjusted, the boring tool is tightly inserted. It is also difficult to greatly improve the characteristics of the control. In the Japanese Patent No. 28629U, there is no description or teaching. The effect of adding ^ is also the method of the document, and the ingot is enlarged. The control of the dish becomes difficult. Therefore, it is desirable to prevent the crack of the ingot by temperature-controlled Cu-Ni, particularly by improving the properties of the 1 S1 alloy based on the inherent action of the alloying element. Although the publication of the 49137 bulletin In addition, there is no description of the usefulness and conditions, and the concentration conditions of the characteristic improvement effect are described. However, other Cosmo alloys which are one of the objects of the present invention are included. ^里J八惟杈特特" 5, provide a more playable add 200837203

The effect of Cr, whereby the Corson-based alloy with greatly improved characteristics is obtained. According to the results of my research on solving the above problems, I found that Cr has a significant effect on the strength and electrical conductivity of Corson alloys under enthalpy conditions. In particular, the present inventors focused on the relationship between Cr and carbon, and found that the effect can be better extracted by controlling the carbon content in the Corson alloy. The moon-free system is completed based on the discovery, and the side is Provided as a copper alloy for electronic materials, containing Ni: 25 to 45 mass%, si: 〇 5 〇 ~ 1.2 mass, Cr: 0.0 〇 3 〇 ~ 〇 2 mass% (where the weight ratio of 盥 w is coffee /_), the remainder consists of Cu and unavoidable impurities, and the amount of carbon is 50 ppm by mass or less. Further, in one embodiment, the steel alloy for an electronic material of the present invention may further contain one or two or more elements selected from the group consisting of W and sn AAg in an amount of 0.5% by mass or less based on the total amount. Further, in another embodiment, the steel alloy for an electronic material of the invention is further selected from the group consisting of

Sb, Be, B, Ti, Zr, A1, c are more than one type of element. Among the groups formed, i or 2, the present invention is further extended to the other side alloy. In the above aspect, the use of the above copper is provided. Further, in the present invention, the electronic machine part of the above steel alloy is further provided. (4) Provided in the surface - according to the invention, the strength and electrical conductivity can be obtained because of the addition of the alloy halogen element, and the η ^ direction electronic material using the Corson steel 8 200837203 alloy. [Embodiment] <Addition amount of Ni and Si> ~Ni and Si are formed by an appropriate heat treatment to form an intermetallic compound, which does not deteriorate the conductivity and can achieve high strength. :. The weight of Si and Ni, as described above, is close to the metering composition: 3: N!/SlS7, and 3.5sNi/sis5. However, even if Ni/Si has a ratio of the above range, the Si_addition amount is not 0.5% by mass, and the desired strength cannot be obtained. If it exceeds u ΐ%, the strength can be increased by 1 疋. Since the rate portion is remarkably lowered, and the liquid phase is generated in the segregation portion, the hot workability is lowered, which is not preferable. Therefore, it is preferably Si: 0.5 to 1 > 2% by mass, preferably 〇5 to 〇 8 % by mass.

The addition of Nl in summer is set to satisfy the above-mentioned preferable denier according to the amount of addition of Si, and in order to balance with the amount of addition of Si, it is preferable to be: 2 5 to "quality 2 is preferably a crime: 3.2 to 4.2% by mass, More preferably, it is 13.5 to 4.0, and the amount of Cr is added. It can be precipitated by precipitation strengthening. On the other hand, 'because the increase in the concentration of addition increases, the amount of helplessness increases. As a result, the conductivity decreases. As a result, the I intensity rises but the peak value rises. Conductivity of strength: 3: Drop: If the above -Si-based (four) 0·2 shell %, preferably 〇〇1~〇1 mass% &, has the same Ni as 200837203 In the Cu-Ni-Si alloy phase having a Si concentration, the final properties are not degraded, and the electrical conductivity can be increased, and the hot workability is improved, and the yield is increased.

Since Cr is preferentially precipitated to the crystal grain boundary during the cooling process during melt casting, the grain boundary can be strengthened, and cracking is less likely to occur during hot working, and the yield can be suppressed from being lowered. Further, since Cr can be easily precipitated in the copper matrix by a suitable heat treatment, it is possible to precipitate a compound of Si, that is, chromium telluride (ChSi, etc.). Therefore, it is combined with solution treatment, cold rolling, and aging treatment to form an alloy. In the special step, 'solid solution components such as Cr3Si which are not precipitated in Ni2Si or the like can be precipitated. Therefore, it is possible to suppress a decrease in conductivity due to solid solution Si, and it is possible to increase the conductivity without loss of strength. That is, Cr precipitated at the grain boundary during dissolution casting is solid-dissolved by solid solution = then solid solution (4). In general Cu_

In the amount of the 81 added in the di-n-alloy, the S 曰 which does not contribute to the aging precipitation is directly dissolved in the parent phase and inhibits the conductivity. ^ ^ 1 is wrong by adding Shi Xihua / 疋 疋 Cr Cr to further Telluride - Si prepared by the people of the past, the Cu-Ni system is comparable to the Meng, which can reduce the amount of solid solution Si and improve the conductivity. The strength of the mussels, however, is less than 0.003 mass%, and when it is less than 0.003 mass%, it is rolled, ', and if it exceeds (the object. Further, in the final characteristics, Cr_Si is precipitated again.

The excess of Cr and the hardening of the work of everyone in the Hesishan Mountain are small, and the addition of the hook is not preferable because it will not help the reinforcement, and the workability and the #f Si compound are deteriorated and plated. <Carbon content> 200837203 In order to suppress the active metal Si-produced alpaca in the case of melt-casting Ni-si system, it is usually carried out in a reductive atmosphere under the conditions of refining and gasification to form a dissolved scale. Most of the melt is a member containing a large amount of carbon such as Mushan =. Therefore, in the prayer:: gold contains more C impurities. however,. When the carbide formation in the copper melt is higher than that of the rabbit compound, the amount of Cr precipitated at the grain boundary will decrease, the grain boundary will be strong, and the effect will be weakened, which will impair the yield improvement effect. Once the c-cylinder is formed, it is difficult to be treated by solid solution, so that 苴 、, Γ / 、, solid/close, not only contributes to the precipitation of aging.

Cr will decrease, and it will also damage the final characteristics of the bending damage. ...and the plating property is therefore large. The inventor found that due to the combination of the ancient p and the book + kg 3, the extreme pole 1 C will be added by

Cr - Ni - Si from Cr is a ΛΑ t amp & 特性 的 的 的 的 的 的 的 的 的 的 的 的 的 的 的 的 特性 特性 特性 特性 特性 特性 特性 特性 特性 特性 特性 特性 特性 特性 曰 曰 曰 曰 曰 曰 曰 曰 曰 曰In addition, it is also known that although the stone anti-inclusion is 50 ppm by mass or less, thermal processing and hSi (11) shape 11 which contributes to improvement in electrical conductivity are also obtained. * The method of controlling the range of the above-mentioned range is, for example, a raw material for reducing the oil content of the attached material, stirring after the raw material is melted, adjusting the amount of charcoal coating, and encapsulating by inert gas such as argon gas to prevent oxidation of the active metal. Covering (rather than covering the surface of the molten liquid in the series), and vacuum lamination. In this case, the carbon content in the alloy can be less than 50 ppm by mass: = eight at 40 mils or less, 3 〇 mass 卯 m or less, or even 25 mass ppm or less. The carbon content of the Cu-Nl~Si alloy of the present invention is, for example, 10 to 30 ppm by mass. 11 200837203 On this point, in the above-mentioned Japanese Tai Zhi Zhi Chu 2 Λ /1 η, y 4 Japanese guide Lie 3049137, for the formation of carbides or oxides in Cr, right to hope for S w hand milk temple The effect of sharply decreasing the concentration at the grain boundary is not mentioned. &lt;Mg, Mn, Sn, and Ag&gt; In the Cu to Ni-Si-based alloy of the present invention, 4, &gt; Α τ , , , , , , , A group consisting of Μη, Sn, and Ag: a species or two or more kinds of halogens, which can be almost non-destructive, have electrical conductivity, and can improve stress relaxation characteristics. When the amount of addition is less than 0.01% by mass, the effect is insufficient. When the amount is more than 0.5% by mass, the manufacturing property such as prayer property and hot workability and the electrical conductivity of the product are impaired, so it is preferable to add 001 to 0. · 5 mass%. <Other Additive Elements> By adding a predetermined amount of zn, p, AS, sb, Be, B, Ti, z" A1 Co and Fe, various effects can be exhibited and mutually compensated, not only having improved strength and electrical conductivity. The effect of improving the bending workability, the plating property, and the refinement of the ingot structure to improve the manufacturability such as hot workability, and therefore, in the Cu_Ni-Si alloy of the present invention, The above-mentioned characteristics are appropriately added to the above-mentioned i or more than 70% by mass of the total amount of 2.0% by mass or less. When the amount of the elements is less than 〇 (four)% by mass of the total amount of the elements, the desired effect cannot be obtained. When it exceeds 2,0% by mass, the decrease in conductivity and the deterioration of the excitation &amp; ^ ^ &amp; properties become remarkable, so the total amount is 0_001 to 2_〇% by mass, more preferably 0.01 to 1%. 〇% by mass. In addition, in the range which does not adversely affect the characteristics of the Cu-Ni-Si alloy of the present invention, the element 12, which is not specifically described in the present specification, may be added. Manufacturing method of the invention. This mouth gold, in addition to controlling the carbon content, u Nl Sl It is manufactured by the usual manufacturing method. It consists of =2,-Si-based alloys or is suitable for electricity. It is not necessary for special use; ^Ming,: Health! Choosing the most appropriate method" It is considered that the method is the same. However, for the sake of exemplification, the general shoulder material is used, and the atmospheric melting furnace is used to melt the original steel such as electrolytic steel, Ni, Si, Cr, etc., and the smelting crucible is transferred to the desired composition. At this time, borrowing the oil in the raw material: the control method for introducing the atmosphere into the atmosphere, (4) melting the second and then performing the hot-drying and repeatedly performing the cold drying and the hot spot = the strip having the desired thickness and characteristics In the heat treatment, the grain treatment is treated in a timely manner. In the solution treatment, ~=(10) generation == heat, ... the compound is a compound in the Cu base material, and the base material is recrystallized. At the same time as the case of the solid bath treatment, the aging treatment is carried out at a temperature of 35 〇 to 55 MPa for 1 hour or more, and the Ni dissolved in the solution treatment and the compound and the compound of Cr a Si are dissolved. Precipitated in the form of fine particles. Increased strength and conductivity by 1 aging treatment In order to obtain higher strength, the crucible is sometimes cold-rolled before and/or after aging. Moreover, after aging, rolling is performed, and de-stressing annealing (low-temperature annealing) is performed after cold rolling. In the embodiment, the Cu—Nl—Si-based copper alloy of the present invention has a safety limit stress of 780 MPa or more and a conductivity of 45% IACSg. 13 200837203

Further, the 0.2/6 queen has a stress limit of more than 86 〇 MPa and a conductivity of 43% IACS or more, and further 0.2% safety limit stress is 89 〇 MPa or more and a conductivity of 40% IACS or more. The l~ month Cu~Ni-Si alloy can be processed into various copper-stretching products such as plates, strips, tubes, rods and wires, and the Cu-Ni-Si-based copper alloy of the present invention can be used for simultaneously requiring high strength. And electronic equipment parts such as lead frames, connectors, locks, terminals, relays, switches, and foils for secondary batteries with high conductivity (or thermal conductivity). EXAMPLES The following is a description of specific examples of the invention, but these examples are provided to provide a further understanding of the invention and the advantages thereof. The copper alloy used in the examples of the present invention, as shown in Table ,, has a suitable addition of Mg in a copper alloy modified to a content of Ni, Si and Cr,

Composition of Sn Ag, di-I, Fe, B and c〇. Further, the copper alloy used in the comparative example was a Cu-Ni-Si bismuth alloy having parameters outside the range of the present invention. The copper alloys of the various compositions contained in Table 1 XI are melted in a high-frequency refining furnace = 1300 C to be cast into ingots having a thickness of 3 〇 mm. At this time, the amount of carbon is controlled by adjusting the oil content in the raw material, adjusting the amount of charcoal coating, introducing a control method for reducing the gaseous gas, and stirring the molten liquid. Then, after heating the ingot, it was hot rolled to a thickness of 1 mm and rapidly cooled. In order to remove the surface of the skin, the end face was cut to a thickness of 8 mm, and the error was: cold rolling to a plate having a thickness of 〇2 mm. Then, according to the amount of addition and &amp; addition, the solution treatment at 850 to 100 (rC for 12 sec seconds, immediately water-cooled. 14 200837203 Then, cold rolling to 0.1 mm, and finally according to the addition amount at 4 〇〇 to 55 〇 〇 实施 〇 实施 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性 惰性Tensile test on top, 2 0.2% safety limit stress (YS; called, conductivity (EC; %ι aspect is obtained by measuring volume resistivity by Wheatstone bridge. Evaluation of strictness is used) The W-shaped mold was subjected to 9 〇 under the conditions of the sample plate:: semi-controlled. The bending was performed by optical microscopy on the bending process. ^^ The trace was judged to be practical without the observation of the heart surface. It is χ. Α is Ο, when the crack is confirmed, the carbon content is recorded, so that the metal test H is high (four) solution ~; J frequency combustion, measured by LECO company for quantitative analysis. Carbon 15 200837203 [Table 1] Composition (% lean) Ni Si Cr Mg, Μη, ΰη, Ag Other hot-rolled cracks YS (MPa) EC 1 recorded from (®/(iACS) processability C fcpm) %圃,m τι 2.5 0.5 0.003 - - [m ax 4.5 1.2 0.2 0.5 2.0 50 Example 1 2.7 0.6 0.005 No 750 48 δ ~16 丄2.7 0.6 0.05 No 755 47 0 23 3 2.7 0,6 0.1 No 770 46 ο 38 4 2.7 0.6 0.05 0.2Me 780 46 〇23 2.7 0.6 0.05 O .IMn no 780 45 Q 23 6 2,7 0.6 0,05 "0,3Sn no 780 45 ,,ρ 23~ 7 2.7 0.6 0.05 0.3Sn . O.lAg m 780 45 Ο 23 _ 8 4.0 0.9 0.005 without 860 43 ο 18 9 4.0 0.9 0.05 No 870 42 〇25 10 4.0 0.9 0.1 No 870 42 ρ 40 ,, 11 4.0 0.9 0.17 No 875 42 〇44 12 4.0 A 0.9 0.05 0.2M2 No 890 41 〇25 13 4.0 0.9 0.05 O.IMn No 890 41 ο 25 14 4.0 _ 0.9 0.05 0.3Sn No 890 41 〇25 15 4.0 0,9 0.05 0.3Sn , O.lAe No 890 41 〇25 16 4.0 0.9 0.1 〇.〇3Ti 0.03Fe k 890 40 0 40 17 4.5 1.00 0.005 930 38 〇18 18 4.5 . 1.00 0Λ7 No 940 42 43 19 4.5 1.00 0.05 0.005B No 940 37 〇28 20 4.5 1.00 0.1 O.lCo No 960 37 _ 0_ 41 Comparative Example 1 2.7 0.6 - 750 40 〇 2 2 4.0 0.9 • Light phase 860 37 ο 3 3 2.7 0.6 0.0005 A slight 750 41 〇 16 4 4.0 0,9 0.0005 860 38 〇19 5 2J ' 0.6 0.0005 Change home m 53 6 4.0 0.9 0.0005 砝 砝 im 56 7 4.0 0.9 0,05 mm 860 36 X 65 8 4.0 0.9 0.1 —Mt. 860 36 X 78 9 2.7 _ 0.6 0.3 760 46 X 40 10 4.0 0.9 0.3 Minor 860 42 X 43 11 4.0 0.9 0.3 Light emblem 860 35 X 85 12 4.0 0.9 0.05 0.6Mc Inferior name cracks 15 13 4.0 0.9 0.05 0,8Mn Fly micro 900 1 21 X 15 Examples 1 to 7 and Comparative Example 1. The common points of 3, 5, and 9 are Ni: 2·7 mass%, and Si: 0.6 mass%. When the content of c r was sequentially increased from Examples 1 to 3 on the right, it was found that the decrease in EC was suppressed as much as possible and the YS was improved. In Examples 4 to 7, it was found that by further adding Mg, Mn, %, and Ag, it is possible to further improve YS. However, in Comparative Example 1, since Cr was not contained, solid solution Si increased, Ec decreased, and slight cracks occurred during hot rolling. In Comparative Example 3, although Cr was contained, since it was less than the predetermined amount, the effect was insufficient, and solid solution Si increased and EC decreased, and slight cracking occurred during hot rolling. In Comparative Example 5, as in Comparative Example 3, the content of ruthenium was small, and the amount of c+ was more than a predetermined amount. Therefore, cracks of an unevaluable degree occur when the heat is applied. In Comparative Example 9, since the Cr content was more than a predetermined amount, coarse a particles were generated, and slight cracks occurred during hot rolling, and the bending workability was also inferior. &lt;Cu-based alloy containing Ni: 4.0% by mass and Si: 〇9% by mass> Common Examples 8 to 16 and Comparative Examples 2 and 4 of 6 to 8 and 1 〇 to 13 contain Ni: 4.0 mass %, Si: 〇·9 mass%. When the content of Cr was sequentially increased from Examples 8 to 11, it was found that the decrease in EC can be suppressed as much as possible and the Ys can be improved. Further, since the content is higher than that of Examples 1 to 7, the YE is high and the corresponding EC is low. In Examples 12 to 15, it is understood that ZnO can be further improved by further adding Mg, Mn, Sn, and Ag. In Example 16, Ti and Fe were added as other additive elements, and it was found that YS can be improved at this time. However, in Comparative Example 2, since Cr was not contained, solid solution Si became large, Ec decreased, and slight cracks occurred during hot rolling. In Comparative Example 4, since Cr was contained, since it was less than a predetermined amount, the effect was insufficient, and solid solution Si was increased and Ec was decreased, and slight cracks occurred during hot rolling. In Comparative Example 6, the Cr content was small as in Comparative Example 4, and the c content was also more than a predetermined amount. Therefore, cracks of an unevaluable degree occur during hot rolling. In Comparative Examples 7 and 8, since the C content is more than a predetermined amount, the carbide of Cr 17 200837203 is formed, and on the other hand, the formation of the cerium chrome is reduced, the solid solution w is increased, and this is lowered, and a slight amount is generated during hot rolling. Cracked. Further, the bending workability is also inferior. Comparative Example H) Since the Cr content was more than a predetermined amount, coarse ruthenium particles were generated, and slight cracks occurred during hot rolling, and the bending workability was also poor. _ Comparative Example 11 was similar to Comparative Example 10 in that the content of the mixture was large and the C content was more than a predetermined amount. Since the C content is more than a predetermined amount, the carbide of & is formed, on the other hand, the formation of chromium telluride is reduced, the solid solution Si is increased, and the Ec is decreased. Further, the bending workability is also inferior. Comparative Examples 12 and 13 are examples in which the addition and the number of additions exceed a predetermined amount. In Comparative Example 12 in which too much Mg was added, the cast skin (deterioration of the coffee cake and cracking during hot rolling) was not evaluated. In Comparative Example 13 in which too much Μ was added, slight cracking occurred during hot rolling and Ec and The bending workability is inferior. <Ni-Si-based alloy containing Ni: 4.5 mass% and Si: U mass%> Examples 17 to 20 contain Ni: 4.5 mass H 〇 mass%. The content is higher than those of Examples 1 to 16, so YE is high, and EC is low correspondingly. &lt;Effect of carbon content&gt; Fig. 1 shows that YS is the horizontal axis and EC is the vertical axis, and Ni, Si, and Cr are specified. In the range where the same content 'carbon amount is the range of the range (Example 9 and !〇), and the stone ϊ is outside the specified range (Comparative Examples 7 and 8), it is known that even if the slave contains only 25 The difference in mass ppm will also produce a significant difference in ys and π. [Simplified illustration] 18 200837203 t Figure 1 shows the relationship between intensity and conductivity (the effect of carbon content). 】 no 19

Claims (1)

200837203 X. Patent application scope: 1 · Copper alloy for electronic materials' is characterized by: Containing Ni: 2.5 to 4.5% by mass, 8丨: 〇.5〇~12% by mass, ^: 〇&lt;〇〇30~ 0.2% by mass (wherein the weight ratio to Si is 3 or /7), and the rest is composed of CU and unavoidable impurities, and the amount of carbon is 5 〇 mass ppm or less. 2. The steel alloy for electronic materials according to the scope of the patent application, further comprising 1 or 2 of the group consisting of Mg, Mn, h and Ag in a total amount of 〇·5 mass% More than one element. 3. The copper alloy for electronic materials according to the second or second aspect of the patent application, further comprising Zn, p, As Sb Be, B, Τι, Zr, Al, which is 2% by mass or less based on the total amount. One or two or more elements of the group consisting of Co, Fe, and Fe. 4. A copper alloy which is a copper alloy according to any one of claims 1 to 3. 5. An electronic machine part using the copper alloy of any one of the claims 1-3. Eleven, circle: as the next page 20