Copper alloy, copper alloy plastic working material, assembly for electronic and electric equipment, terminal, bus bar, lead frame, and heat dissipation substrate

Abstract

Provided is a copper alloy having high electrical conductivity and excellent heat resistance, wherein the content of Mg is more than 10 mass ppm and 100 mass ppm or less, the remainder being Cu and unavoidable impurities, the content of S is 10 mass ppm or less, the content of P is 10 mass ppm or less, the content of Se is 5 mass ppm or less, the content of Te is 5 mass ppm or less, the content of Sb is 5 mass ppm or less, the content of Bi is 5 mass ppm or less, the content of As is 5 mass ppm or less, the total content of S, P, Se, Te, Sb, Bi, and As is 30 mass ppm or less, the mass ratio of [[Mg]] / [[S+P+Se+Te+Sb+Bi+As]] is 0.6 or more and 50 or less, the electrical conductivity is 97% IACS or more, the average value of the orientation density in the range of φ2=0°, φ1=0°-20°, Φ=35°-55° is 1.3 or more and less than 20.0, and the area ratio of crystals having crystal orientation within 10° with respect to the S orientation {123} <634> is 10% or less.

Description

Technical Field

[0001] This invention relates to a copper alloy suitable for electronic and electrical equipment components such as terminals, busbars, lead frames, and heat dissipation substrates; copper alloy plastic processing materials made of the copper alloy; and electronic and electrical equipment components, terminals, busbars, lead frames, and heat dissipation substrates.

[0002] This application claims priority based on Japanese Patent Application No. 2021-214029, filed on December 28, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] In the past, highly conductive copper or copper alloys were used in electronic and electrical equipment components such as terminals, busbars, lead frames, and heat dissipation parts.

[0004] Here, with the increasing current of electronic devices or electrical equipment, in order to reduce current density and dissipate heat caused by Joule heating, it is also an attempt to increase the size and thickness of the electronic and electrical components used in these electronic devices or electrical equipment.

[0005] In order to cope with high current, pure copper materials such as oxygen-free copper with excellent conductivity are used in the components of the aforementioned electronic and electrical equipment. However, with the heat generated when energized or the high temperature of the operating environment, copper materials with excellent heat resistance (heat resistance means that the hardness does not easily decrease at high temperatures) are required, but pure copper materials have poor properties in these aspects, which makes them unusable in high-temperature environments.

[0006] Therefore, Patent Document 1 discloses a copper rolled plate containing Mg in the range of 0.005% by mass or more and less than 0.1% by mass.

[0007] Regarding the copper rolled plate described in Patent Document 1, since it has a composition containing Mg in the range of 0.005% by mass and less than 0.1% by mass, with the remainder consisting of Cu and unavoidable impurities, it is possible to improve the strength and heat resistance without significantly reducing the conductivity by dissolving Mg in the copper matrix.

[0008] Patent Document 1: Japanese Patent Application Publication No. 2016-056414(A)

[0009] Here, because these materials improve their heat resistance by adding solute elements, they have lower electrical conductivity compared to pure copper.

[0010] Recently, in order to effectively suppress heat generation when large currents are flowing through copper materials used in the aforementioned electronic and electrical equipment, and in order to enable applications using pure copper materials, there is a demand for further improvements in conductivity.

[0011] Furthermore, since the aforementioned electronic and electrical equipment components are frequently used in high-temperature environments such as engine compartments, the copper materials constituting these components require significantly improved heat resistance than ever before. In other words, a copper material with a balanced improvement in both conductivity and heat resistance is needed. Summary of the Invention

[0012] The present invention was made in view of the above circumstances, and its object is to provide a copper alloy with high conductivity and excellent heat resistance, copper alloy plastic processing material, electronic and electrical equipment components, terminals, busbars, lead frames, and heat dissipation substrates.

[0013] To address this issue, the inventors conducted in-depth research and obtained the following insights: In order to achieve a balanced balance between high conductivity and excellent heat resistance, by adding trace amounts of Mg while limiting the content of elements that form compounds with Mg and by implementing microstructure control consistent with the composition, it is possible to improve conductivity and heat resistance in a more balanced manner than before.

[0014] This invention is based on the above-mentioned insights. The copper alloy of this invention is characterized by having a Mg content in the range of more than 10 ppm by mass and less than 100 ppm by mass, with the remainder being Cu and unavoidable impurities. Among these unavoidable impurities, the S content is less than 10 ppm by mass, the P content is less than 10 ppm by mass, the Se content is less than 5 ppm by mass, the Te content is less than 5 ppm by mass, the Sb content is less than 5 ppm by mass, the Bi content is less than 5 ppm by mass, the As content is less than 5 ppm by mass, and the total content of S, P, Se, Te, Sb, Bi, and As is less than 30 ppm by mass. The Mg content is set to […]. When the total content of S, P, Se, Te, Sb, Bi, and As is set as [S+P+Se+Te+Sb+Bi+As], their mass ratio [Mg] / [S+P+Se+Te+Sb+Bi+As] is in the range of 0.6 or more and 50 or less, the conductivity is 97% IACS or more, and when the crystal orientation distribution function obtained by texture analysis based on the EBSD method is expressed in Euler angles, the average value of the orientation density in the range of φ2=0°, φ1=0°~20°, and Φ=35°~55° is 1.3 or more and less than 20.0, and the area ratio of crystals with crystal orientation within 10° relative to S orientation {123}<634> is 10% or less.

[0015] According to the copper alloy with this composition, since the contents of Mg and the elements S, P, Se, Te, Sb, Bi and As that form compounds with Mg are specified as above, the heat resistance can be improved without significantly reducing the conductivity by dissolving trace amounts of Mg in the copper matrix phase. Specifically, the conductivity can be increased to 97% IACS or higher.

[0016] Furthermore, by controlling the crystal structure to keep the orientation density and S orientation within the above range, recovery or recrystallization caused by dislocation movement is less likely to occur, thus significantly improving heat resistance.

[0017] Here, in the copper alloy of the present invention, the content of Ag is preferably in the range of 5 ppm by mass or more and 20 ppm by mass or less.

[0018] At this point, because it contains Ag within the above range, Ag segregates near the grain boundaries, and grain boundary diffusion is suppressed, thereby further improving heat resistance.

[0019] Furthermore, in the copper alloy of the present invention, the heat resistance temperature is preferably 260°C or higher.

[0020] At this point, since the heat resistance temperature is above 260℃, the heat resistance is excellent and it can be used stably in high-temperature environments.

[0021] The copper alloy plastic processing material of the present invention is characterized in that it is composed of the aforementioned copper alloy.

[0022] The copper alloy plastic processing material with this structure has excellent conductivity and heat resistance due to its composition, making it particularly suitable as a raw material for electronic and electrical equipment components such as terminals, busbars, lead frames, and heat dissipation substrates used in high-current applications and high-temperature environments.

[0023] Here, the copper alloy plastic processing material of the present invention can be a shaped strip.

[0024] At this point, even if strong processing is required to form irregular strips with different thicknesses on cross sections orthogonal to the length direction, heat resistance can be fully ensured.

[0025] Furthermore, it is preferable that the surface of the copper alloy plastic processing material of the present invention has a metal plating layer.

[0026] At this time, due to the metallic coating on the surface, it is particularly suitable as a raw material for components of electronic and electrical equipment such as terminals, busbars, lead frames, and heat dissipation parts.

[0027] The electronic and electrical equipment component of the present invention is characterized in that it is made of the aforementioned copper alloy plastic processing material. Furthermore, the electronic and electrical equipment component of the present invention includes terminals, busbars, lead frames, heat sinks, etc.

[0028] Because the electronic and electrical equipment components are manufactured using the aforementioned copper alloy plastic processing material, they can exhibit excellent characteristics even in high-current applications and high-temperature environments.

[0029] The terminal of the present invention is characterized in that it is made of the aforementioned copper alloy plastic processing material.

[0030] Because the terminals are made using the aforementioned copper alloy plastic processing material, they exhibit excellent characteristics even in high-current applications and high-temperature environments.

[0031] The busbar of the present invention is characterized in that it is made of the aforementioned copper alloy ductile material.

[0032] Because this busbar is made of the aforementioned copper alloy plastic processing material, it can exhibit excellent properties even in high-current applications and high-temperature environments.

[0033] The lead frame of the present invention is characterized in that it is made of the aforementioned copper alloy plastic processing material.

[0034] Because the lead frame is made of the aforementioned copper alloy plastic processing material, it can exhibit excellent characteristics in high-current applications and high-temperature environments.

[0035] The heat dissipation substrate of the present invention is characterized in that it is made of the aforementioned copper alloy plastic processing material.

[0036] Because the heat dissipation substrate is made of the aforementioned copper alloy plastic processing material, it can exhibit excellent characteristics even in high-current applications and high-temperature environments.

[0037] According to the present invention, it is possible to provide a copper alloy with high conductivity and excellent heat resistance, a copper alloy ductile material, components for electronic and electrical equipment, terminals, busbars, lead frames, and heat dissipation substrates. Attached Figure Description

[0038] Figure 1 This is a cross-sectional diagram illustrating the copper alloy (copper alloy ductile material) of this embodiment.

[0039] Figure 2 This is a flowchart of the copper alloy manufacturing method according to this embodiment. Detailed Implementation

[0040] Hereinafter, a copper alloy according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0041] The copper alloy of this embodiment is most suitable as a raw material for components of electronic and electrical equipment such as terminals, busbars, lead frames, and heat sinks.

[0042] Furthermore, the copper alloy ductile material of this embodiment is composed of the copper alloy of this embodiment. For example... Figure 1 As shown, the copper alloy plastic processing material 10 of this embodiment is a shaped strip with a thick portion 11 and a thin portion 12 of different thicknesses on a cross section orthogonal to the length direction.

[0043] The copper alloy of this embodiment has a composition in which the content of Mg is in the range of more than 10 ppm by mass and less than 100 ppm by mass, the remainder being Cu and unavoidable impurities. Among the unavoidable impurities, the content of S is less than 10 ppm by mass, the content of P is less than 10 ppm by mass, the content of Se is less than 5 ppm by mass, the content of Te is less than 5 ppm by mass, the content of Sb is less than 5 ppm by mass, the content of Bi is less than 5 ppm by mass, the content of As is less than 5 ppm by mass, and the total content of S, P, Se, Te, Sb, Bi and As is less than 30 ppm by mass.

[0044] Furthermore, when the content of Mg is set as [Mg] and the total content of S, P, Se, Te, Sb, Bi and As is set as [S+P+Se+Te+Sb+Bi+As], their mass ratio [Mg] / [S+P+Se+Te+Sb+Bi+As] is in the range of 0.6 or more and 50 or less.

[0045] In addition, in the copper alloy of this embodiment, the content of Ag can be in the range of 5 ppm by mass or more and 20 ppm by mass or less.

[0046] Furthermore, in the copper alloy of this embodiment, the conductivity is 97% IACS or higher.

[0047] Furthermore, in the copper alloy of this embodiment, the heat resistance temperature is preferably 260°C or higher.

[0048] Furthermore, in the copper alloy of this embodiment, when the crystal orientation distribution function obtained by texture analysis based on the EBSD method is expressed in Euler angles, the average value of the orientation density in the range of φ2=0°, φ1=0°~20°, and Φ=35°~55° is 1.3 or more and less than 20.0.

[0049] Furthermore, in the copper alloy of this embodiment, the area ratio of crystals having a crystal orientation of 10° or less relative to the S orientation {123}<634> is 10% or less.

[0050] Here, the reasons for specifying the composition, various properties, and crystal structure of the copper alloy in this embodiment as described above will be explained below.

[0051] (Mg)

[0052] Mg is an element that can increase the heat resistance temperature without significantly reducing the conductivity by being dissolved in the copper matrix.

[0053] Here, when the Mg content is below 10 ppm by mass, its effect may not be fully realized. On the other hand, when the Mg content exceeds 100 ppm by mass, the conductivity may decrease.

[0054] Based on the above, in this embodiment, the Mg content is set within the range of more than 10 ppm by mass and less than 100 ppm by mass.

[0055] In addition, in order to further improve the heat resistance temperature, the Mg content is preferably set to 20 ppm by mass or more, more preferably 30 ppm by mass or more, and even more preferably 40 ppm by mass or more.

[0056] Furthermore, in order to further improve conductivity, the Mg content is preferably set to 90 ppm by mass or less, more preferably 80 ppm by mass or less, and even more preferably 70 ppm by mass or less.

[0057] (S, P, Se, Te, Sb, Bi, As)

[0058] The elements mentioned above, such as S, P, Se, Te, Sb, Bi, and As, are commonly found to easily infiltrate copper alloys. Furthermore, these elements readily react with Mg to form compounds, potentially reducing the solid solution effect of trace amounts of added Mg. Therefore, the content of these elements needs to be strictly controlled.

[0059] Therefore, in this embodiment, the content of S is limited to less than 10 ppm by mass, the content of P is limited to less than 10 ppm by mass, the content of Se is limited to less than 5 ppm by mass, the content of Te is limited to less than 5 ppm by mass, the content of Sb is limited to less than 5 ppm by mass, the content of Bi is limited to less than 5 ppm by mass, and the content of As is limited to less than 5 ppm by mass.

[0060] Furthermore, the total content of S, P, Se, Te, Sb, Bi and As is limited to below 30 ppm by mass.

[0061] In addition, the content of S is preferably 9 ppm by mass or less, and more preferably 8 ppm by mass or less.

[0062] The content of P is preferably 6 ppm by mass or less, and more preferably 3 ppm by mass or less.

[0063] The content of Se is preferably 4 ppm by mass or less, and more preferably 2 ppm by mass or less.

[0064] The Te content is preferably 4 ppm by mass or less, and more preferably 2 ppm by mass or less.

[0065] The Sb content is preferably 4 ppm by mass or less, and more preferably 2 ppm by mass or less.

[0066] The content of Bi is preferably 4 ppm by mass or less, and more preferably 2 ppm by mass or less.

[0067] The content of As is preferably less than 4 ppm by mass, and more preferably less than 2 ppm by mass.

[0068] Furthermore, the total content of S, P, Se, Te, Sb, Bi and As is preferably 24 ppm by mass or less, and more preferably 18 ppm by mass or less.

[0069] (〔Mg〕 / 〔S+P+Se+Te+Sb+Bi+As〕)

[0070] As mentioned above, elements such as S, P, Se, Te, Sb, Bi, and As readily react with Mg to form compounds. Therefore, in this embodiment, the form in which Mg exists is controlled by specifying the ratio of the content of Mg to the total content of S, P, Se, Te, Sb, Bi, and As.

[0071] When the Mg content is defined as [Mg] and the total content of S, P, Se, Te, Sb, Bi, and As is defined as [S+P+Se+Te+Sb+Bi+As], if the mass ratio [Mg] / [S+P+Se+Te+Sb+Bi+As] exceeds 50, Mg exists in excess in copper in a solid solution state, which may reduce conductivity. On the other hand, when the mass ratio [Mg] / [S+P+Se+Te+Sb+Bi+As] is less than 0.6, Mg may not be sufficiently dissolved, and the heat resistance temperature may not be sufficiently increased.

[0072] Therefore, in this embodiment, the mass ratio [Mg] / [S+P+Se+Te+Sb+Bi+As] is set in the range of 0.6 or more and 50 or less.

[0073] In addition, in order to further improve conductivity, the mass ratio of [Mg] / [S+P+Se+Te+Sb+Bi+As] is preferably set to 35 or less, and more preferably to 25 or less.

[0074] Furthermore, in order to further improve heat resistance, the mass ratio of [Mg] / [S+P+Se+Te+Sb+Bi+As] is preferably set to 0.8 or more, and more preferably to 1.0 or more.

[0075] (Ag: 5 ppm or more by mass and 20 ppm or less by mass)

[0076] Ag is almost insoluble in the Cu matrix within the typical operating temperature range of electronic and electrical equipment, below 250°C. Therefore, trace amounts of Ag added to copper will segregate near the grain boundaries. This hinders atomic movement at the grain boundaries, suppressing grain boundary diffusion and thus improving heat resistance.

[0077] Here, when the Ag content is 5 ppm by mass or higher, its effect can be fully realized. On the other hand, when the Ag content is 20 ppm by mass or lower, conductivity can be ensured and the increase in manufacturing costs can be suppressed.

[0078] Based on the above, in this embodiment, the content of Ag is set within the range of 5 ppm by mass or more and 20 ppm by mass or less.

[0079] Here, to further improve heat resistance, the Ag content is preferably set to 6 ppm by mass or more, more preferably 7 ppm by mass or more, and even more preferably 8 ppm by mass or more. Furthermore, to reliably suppress the decrease in conductivity and the increase in cost, the Ag content is preferably set to 18 ppm by mass or less, more preferably 16 ppm by mass or less, and even more preferably 14 ppm by mass or less.

[0080] In addition, when Ag is intentionally omitted, the Ag content can be less than 5 ppm by mass.

[0081] (Other unavoidable impurities)

[0082] Other unavoidable impurities besides the elements mentioned above include Al, B, Ba, Be, Ca, Cd, Cr, Sc, rare earth elements, V, Nb, Ta, Mo, Ni, W, Mn, Re, Ru, Sr, Ti, Os, Co, Rh, Ir, Pb, Pd, Pt, Au, Zn, Zr, Hf, Hg, Ga, In, Ge, Y, Tl, N, Si, Sn, and Li. These unavoidable impurities can be present within a range that does not affect the properties.

[0083] Here, these unavoidable impurities may reduce conductivity, so the total amount is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, more preferably 0.03% by mass or less, and even more preferably 0.01% by mass or less.

[0084] Furthermore, the content of each of these unavoidable impurities is preferably 10 ppm by mass or less, more preferably 5 ppm by mass or less, and even more preferably 2 ppm by mass or less.

[0085] (Average value of orientation density within the range of φ2=0°, φ1=0°~20°, Φ=35°~55°)

[0086] Euler angles represent crystal orientation through the relationship between the sample coordinate system and the crystal axis of each grain. Starting from a state where the crystal axes (XYZ) are aligned, rotations around the (ZXZ) axes (φ1, Φ, φ2) respectively reveal the crystal orientation. By displaying the ODF (crystal orientation distribution function) in three-dimensional Euler space using series expansion, the distribution of crystal orientation density within the measurement range can be confirmed. Regarding this orientation density distribution, a completely random orientation state obtained from standard powder samples is set to 1. For example, when the orientation density of a certain orientation is 3, it indicates that there are three times as many random orientations of that orientation.

[0087] When expressed in Euler angles (φ1, Φ, φ2), crystal orientations within the ranges of φ2 = 0°, φ1 = 0°–20°, and Φ = 35°–55° represent recrystallized structures formed through a specific combination of heat treatment and processing. Compared to other crystal orientations, these orientations tend to exhibit a greater tendency for strain localization. Therefore, when expressed in Euler angles (φ1, Φ, φ2), if the orientation density increases within the ranges of φ2 = 0°, φ1 = 0°–20°, and Φ = 35°–55°, recovery or recrystallization due to dislocation movement becomes less likely, thus improving the heat resistance of the copper material.

[0088] Therefore, by making the average value of the above-mentioned orientation density 1.3 or higher, sufficiently high heat resistance can be obtained. On the other hand, by making the average value of the above-mentioned orientation density less than 20.0, constant strength can be obtained while maintaining heat resistance, thereby improving processability during manufacturing.

[0089] Based on the above, in this embodiment, the average value of the orientation density in the range of φ2=0°, φ1=0°~20°, and Φ=35°~55° is set to be above 1.3 and below 20.0.

[0090] Here, the average value of the aforementioned orientation density is preferably 1.6 or more, more preferably 2.0 or more, even more preferably 2.5 or more, and most preferably 3.0 or more. On the other hand, the average value of the aforementioned orientation density is more preferably 18 or less, and even more preferably 15 or less.

[0091] Furthermore, when there are thick and thin sections with different material structures, such as in irregularly shaped strips, the orientation density of the thick and thin sections in the ranges of φ2=0°, φ1=0°~20°, and Φ=35°~55° are all within the above ranges when expressed in Euler angles (φ1, Φ, φ2).

[0092] (The area ratio of crystals with crystal orientations within 10° relative to the S-orientation {123}<634> (hereinafter also referred to as the S-orientation ratio))

[0093] S-orientation {123}<634> is a representative rolling texture of copper. However, compared with other orientations, strain is more likely to be localized. Therefore, the proportion of S-orientation increases, and recovery caused by dislocation movement is more likely to occur, thus the heat resistance of copper material deteriorates.

[0094] Based on the above, in this embodiment, the area ratio of crystals having a crystal orientation within 10° relative to the S orientation {123}<634> is set to 10% or less.

[0095] Here, the area ratio of crystals having a crystal orientation of 10° or less relative to the S orientation {123}<634> is preferably 8% or less, more preferably 6% or less, and even more preferably 4% or less.

[0096] Furthermore, although there is no specific lower limit required, it is usually above 0.1% when the shape is formed by rolling.

[0097] Furthermore, when there are thick and thin portions with different material structures, such as in irregularly shaped bands, the area ratio of crystals with crystal orientations within 10° relative to the S orientation {123}<634> in both the thick and thin portions is within the aforementioned range.

[0098] (Conductivity)

[0099] In the copper alloy of this embodiment, the conductivity is 97.0% IACS or higher. By achieving a conductivity of 97.0% IACS or higher, heat generation during energization can be suppressed, making it a suitable alternative to pure copper for use as components in electronic and electrical equipment such as terminals, busbars, lead frames, and heat dissipation parts.

[0100] Here, the conductivity is preferably 97.5% IACS or higher, more preferably 98.0% IACS or higher, more preferably 98.5% IACS or higher, and even more preferably 99.0% IACS or higher.

[0101] Although not specifically limited, the conductivity can be below 101.5% IACS, below 101.0% IACS, or below 99.6% IACS.

[0102] Furthermore, when there are thick and thin sections, such as irregularly shaped strips, and their material structures are different, the conductivity of both the thick and thin sections is within the aforementioned range.

[0103] (Heat resistance temperature)

[0104] For the copper alloy of this embodiment, when the heat resistance temperature is high, it is more suitable for use in high-temperature environments.

[0105] Therefore, in the copper alloy of this embodiment, the heat resistance temperature is preferably 260°C or higher.

[0106] Here, the heat resistance temperature is further preferably above 280°C, more preferably above 300°C, and most preferably above 320°C.

[0107] In addition, when there are thick and thin sections with different material structures, such as in irregularly shaped strips, the heat resistance temperature of both the thick and thin sections is within the above range.

[0108] Next, refer to Figure 1 The flowchart shown illustrates the manufacturing method of the copper alloy of this embodiment with this configuration.

[0109] (Melting and casting process S01)

[0110] First, the aforementioned elements are added to the molten copper obtained by melting copper raw materials to adjust the composition, thereby creating a copper alloy molten liquid. Furthermore, elemental substances or master alloys can be used when adding various elements. Moreover, raw materials containing the aforementioned elements can be melted together with copper raw materials. Additionally, recycled materials and waste materials using this alloy can also be used.

[0111] Here, the preferred copper raw material is so-called 4NCu with a purity of 99.99% by mass or higher, or so-called 5NCu with a purity of 99.999% by mass or higher.

[0112] In order to suppress the oxidation of Mg and reduce the hydrogen concentration during melting, it is preferable to carry out melting in an atmosphere of inert gas with low vapor pressure of H2O (such as Ar gas), and to limit the holding time during melting to a minimum.

[0113] Then, the molten copper alloy, with its composition adjusted, is poured into a mold to produce an ingot. Furthermore, when considering mass production, continuous casting or semi-continuous casting is preferred.

[0114] (Homogenization and solution treatment process S02)

[0115] Next, a heat treatment is performed to homogenize and solution-solidify the obtained ingot. Sometimes, intermetallic compounds, primarily composed of Cu and Mg, are present inside the ingot. These intermetallic compounds are generated during solidification due to Mg segregation and concentration. Therefore, to eliminate or reduce these segregations and intermetallic compounds, a heat treatment is performed, heating the ingot to 300°C or higher but below 1080°C, causing Mg to diffuse uniformly within the ingot or to dissolve Mg in the parent phase. Furthermore, it is preferable to perform this homogenization and solution-solidification process (S02) in a non-oxidizing or reducing atmosphere.

[0116] Here, when the heating temperature is below 300℃, solidification will be incomplete, potentially leaving many intermetallic compounds, mainly composed of Cu and Mg, in the parent phase. On the other hand, if the heating temperature exceeds 1080℃, part of the copper raw material will become liquid, and the microstructure and surface condition may become uneven. Therefore, the heating temperature is set within the range of above 300℃ and below 1080℃.

[0117] Furthermore, to improve the efficiency of rough rolling and the homogenization of the microstructure, as described later, hot working can be performed after the homogenization and solution treatment steps S02. In this case, there are no particular limitations on the processing method; for example, rolling, drawing, extrusion, groove rolling, forging, and stamping can be used. Moreover, the hot working temperature is preferably in the range of 300°C or higher and 1080°C or lower.

[0118] (Rough machining process S03)

[0119] Rough machining is performed to form a specified shape. While the temperature conditions in this rough machining step S03 are not particularly limited, to suppress recrystallization or improve dimensional accuracy, it is preferably set within the range of -200°C to 200°C, which is typically used for cold rolling or warm rolling, and particularly preferably at room temperature. Regarding the machining rate, it is preferably 20% or more, and more preferably 30% or more. Furthermore, the machining method is not particularly limited; for example, rolling, drawing, extrusion, groove rolling, forging, stamping, etc., can be used.

[0120] In addition, the roughing process S03 and the intermediate heat treatment process S04 described later can be performed repeatedly.

[0121] (Intermediate heat treatment process S04)

[0122] After the roughing process S03, heat treatment is performed to soften the material or form a recrystallized structure to improve workability.

[0123] At this point, a short-time heat treatment based on a continuous annealing furnace is preferred, as the addition of Ag can prevent the localization of Ag segregation to grain boundaries.

[0124] There are no particular restrictions on the heat treatment conditions, but it is usually carried out in the range of 200°C to 1000°C.

[0125] (Mechanical surface treatment process S05)

[0126] After the intermediate heat treatment step S04, a mechanical surface treatment is performed. The mechanical surface treatment is a process that applies compressive stress to the vicinity of the surface. When combined with the heat treatment step S07 before finishing, as described later, the orientation density increases in the range of φ2=0°, φ1=0°~20°, and Φ=35°~55° when expressed in Euler angles (φ1, Φ, φ2), while the S orientation decreases, thus improving heat resistance.

[0127] Mechanical surface treatment can employ a variety of commonly used methods, such as shot peening, sandblasting, grinding, polishing, polishing and grinding, grinding machine polishing, sandpaper polishing, tension straightening machine treatment, and light rolling with a low reduction rate per pass (a reduction rate of 1 to 10% per pass, repeated three times or more).

[0128] (Irregular shape rolling process S06)

[0129] In the case of an irregularly shaped copper alloy plate in which it is desired that the thick-walled and thin-walled portions are arranged along the width direction, the irregular rolling process S06 can also be performed.

[0130] In the irregular rolling process, the material after the mechanical surface treatment process S05 is subjected to irregular cold rolling through a flat mold with concave and convex surfaces and a roll that faces the forming surface of the mold and moves back and forth along the forming surface, thereby obtaining a copper alloy plate with a coarse irregular cross section with thick and thin walls arranged along the width direction.

[0131] Through the processing in the profile rolling process S06 and the heat treatment process S07 before finishing (described later), the orientation density increases in the range of φ2=0°, φ1=0°~20°, and Φ=35°~55° when expressed in Euler angles (φ1, Φ, φ2). However, since the S orientation also tends to increase, the processing rate is preferably in the range of 5% or more and 90% or less. Furthermore, in order to minimize the difference in material structure between the thick and thin portions and the resulting difference in heat resistance, in the profile rolling process S06, the ratio of the thickness of the thick portion to the thickness of the thin portion is preferably set in the range of 1.1 or more and 8.0 or less.

[0132] (Heat treatment process S07 before finishing)

[0133] Next, heat treatment is performed. In particular, during the profile rolling process S06, recrystallization in the profile rolling process S06 and the heat treatment process S07 before finishing results in an increase in orientation density in the range of φ2=0°, φ1=0°~20°, and Φ=35°~55°, expressed in Euler angles (φ1, Φ, φ2), while the S orientation decreases.

[0134] Here, the heat treatment temperature in the heat treatment process S07 before finishing is preferably in the range of 250°C or higher and 650°C or lower, and the holding time at the heat treatment temperature is preferably in the range of 0.1 hours or higher and 100 hours or lower. For example, when the heat treatment temperature is 400°C, the holding time is preferably set to 10 hours.

[0135] (Finishing process S08)

[0136] After the heat treatment process S07 prior to finishing, the finishing process S08 is performed to adjust the strength. If the finishing process S08 is not performed, the recrystallized structure will remain, resulting in a significant decrease in strength and making it difficult to process.

[0137] In addition, when the strip is made into a shaped strip with thick and thin sections through the shaped rolling process S06, it is preferable to carry out the process by cold working using rolls composed of stepped rolls and flat rolls.

[0138] Since the rolled texture is formed through this finishing process S08, if the processing rate is too high, the orientation density will decrease in the range of φ2=0°, φ1=0°~20°, and Φ=35°~55° when expressed in Euler angles (φ1, Φ, φ2), and the S orientation will also increase.

[0139] Therefore, the machining rate in the finishing process S08 is preferably 50% or less, more preferably 45% or less. Furthermore, the machining rate is preferably 5% or more, and even more preferably 8% or more.

[0140] Alternatively, low-temperature annealing can be performed after the finishing process S08. Furthermore, a straightening process based on a tension straightener or similar device can be added.

[0141] Thus, the copper alloy (copper alloy ductile material) of this embodiment is manufactured. Furthermore, the copper alloy ductile material manufactured by rolling is referred to as a copper alloy rolled sheet.

[0142] Here, in the copper alloy (copper alloy ductile material) 10 of this embodiment, as... Figure 1As shown, the cross section orthogonal to the length direction has a thick portion 11 and a thin portion 12 with different thicknesses. Preferably, the thickness t1 of the thick portion 11 is in the range of 0.2 mm or more and 10 mm or less, and the thickness t2 of the thin portion 12 is in the range of 0.1 mm or more and 5.0 mm or less.

[0143] Furthermore, the ratio t1 / t2 of the thickness t1 of the thick portion 11 to the thickness t2 of the thin portion 12 is preferably in the range of 1.1 or more and 8.0 or less.

[0144] Furthermore, when the irregular rolling process S06 is not performed, the thickness of the copper alloy (copper alloy plastic processing material) 10 is preferably in the range of 0.1 mm or more and 10 mm or less.

[0145] In the copper alloy of this embodiment constructed as described above, the content of Mg is in the range of more than 10 ppm by mass and less than 100 ppm by mass, and the content of S, which forms a compound with Mg, is limited to less than 10 ppm by mass, the content of P is limited to less than 10 ppm by mass, the content of Se is limited to less than 5 ppm by mass, the content of Te is limited to less than 5 ppm by mass, the content of Sb is limited to less than 5 ppm by mass, the content of Bi is limited to less than 5 ppm by mass, the content of As is limited to less than 5 ppm by mass, and the total content of S, P, Se, Te, Sb, Bi and As is limited to less than 30 ppm by mass. Therefore, trace amounts of added Mg can be dissolved in the copper matrix phase, thereby improving the heat resistance temperature without significantly reducing the conductivity.

[0146] Furthermore, when the content of Mg is set to [Mg] and the total content of S, P, Se, Te, Sb, Bi and As is set to [S+P+Se+Te+Sb+Bi+As], since their mass ratio [Mg] / [S+P+Se+Te+Sb+Bi+As] is set in the range of 0.6 or more and 50 or less, the heat resistance temperature can be sufficiently improved without the conductivity decreasing due to excessive solid solution of Mg.

[0147] Therefore, the copper alloy according to this embodiment can achieve both high electrical conductivity and excellent heat resistance. Specifically, setting the conductivity to 97% IACS or higher ensures high conductivity.

[0148] Furthermore, in the copper alloy of this embodiment, when the Ag content is in the range of 5 ppm by mass or more and 20 ppm by mass or less, Ag segregates near the grain boundaries, and grain boundary diffusion is suppressed by the Ag, thereby reliably improving the heat resistance temperature.

[0149] Furthermore, the copper alloy in this embodiment exhibits excellent heat resistance when the heat resistance temperature is above 260°C, and can be used stably even in high-temperature environments.

[0150] The copper alloy plastic processing material of this embodiment is composed of the aforementioned copper alloy, thus exhibiting excellent electrical conductivity and heat resistance, making it particularly suitable as a material for components used in electronic and electrical equipment such as terminals, busbars, lead frames, and heat dissipation substrates.

[0151] Furthermore, the copper alloy plastic processing material of this embodiment is a special-shaped strip with thin and thick portions of different thicknesses on a cross section orthogonal to the length direction. Therefore, by applying the thin and thick portions to each part of the electronic and electrical equipment component, it is possible to obtain an electronic and electrical equipment component with excellent properties.

[0152] Furthermore, when a metal plating layer is formed on the surface of the copper alloy plastic processing material in this embodiment, various properties can be imparted to the surface, making it particularly suitable as a material for electronic and electrical equipment components such as terminals, busbars, and heat dissipation parts.

[0153] Furthermore, since the electronic and electrical equipment components (terminals, busbars, lead frames, heat dissipation components, etc.) of this embodiment are made of the aforementioned copper alloy plastic processing material, they can exhibit excellent characteristics even in high-current applications and high-temperature environments.

[0154] The copper alloy, copper alloy plastic processing material, and electronic and electrical equipment components (terminals, busbars, lead frames, heat dissipation components, etc.) of the embodiments of the present invention have been described above. However, the present invention is not limited thereto, and appropriate modifications can be made without departing from the technical concept of the present invention.

[0155] For example, in the above embodiments, an example of a method for manufacturing copper alloy (copper alloy ductile processing material) has been described, but the method for manufacturing copper alloy is not limited to the method described in the embodiments, and existing manufacturing methods may be appropriately selected.

[0156] Furthermore, in this embodiment, with Figure 1 The irregularly shaped strip shown is an example, but it is not limited to this; it can be an irregularly shaped strip with other cross-sectional shapes, or a strip with a constant thickness. Furthermore, it can also be wire or bar, etc.

[0157] Example

[0158] The results of the confirmation experiments conducted to verify the effectiveness of the present invention will be described below.

[0159] Raw materials consisting of pure copper with a purity of 99.999% by mass or higher obtained by zone refining were loaded into a high-purity graphite crucible and subjected to high-frequency melting in an atmosphere furnace set with Ar gas atmosphere.

[0160] The compositions shown in Tables 1 and 2 were prepared by using 0.1% by mass of various master alloys as described below in the obtained molten copper, and then cast into an insulating (ISOWOOL) mold to produce an ingot. The master alloys were made using high-purity copper with a purity of 6N (99.9999% by mass) or higher and a pure metal with a purity of 2N (99% by mass) or higher. Furthermore, the ingot size was set to approximately 30 mm in thickness, approximately 60 mm in width, and approximately 150–200 mm in length.

[0161] The obtained ingots are heated for 1 hour in an Ar gas atmosphere at various temperature conditions, the surface is ground to remove the oxide film, and then cut into specified sizes.

[0162] Afterwards, the thickness was adjusted to achieve the appropriate final thickness and then cut. For each cut specimen, after rough rolling at room temperature with the processing rates shown in Tables 3 and 4, intermediate heat treatment was carried out under the heat treatment conditions described in Tables 3 and 4.

[0163] Then, mechanical surface treatment was performed on these samples using the methods described in Tables 3 and 4.

[0164] Additionally, polish and grind using #1000 sandpaper.

[0165] The tension straightener uses a tension straightener equipped with multiple φ16mm rollers, at a speed of 100N / mm. 2 Line tension is implemented.

[0166] Regarding light rolling (rolling with a low reduction rate per pass), the final 3 passes were implemented with a reduction rate of 4% per pass.

[0167] Next, except for a portion of the samples, the thick and thin portions were subjected to stepped profile rolling with the thicknesses of the thick and thin portions being the values ​​recorded in Tables 3 and 4, respectively, using a flat die and rolls that faced the forming surface of the die and moved back and forth along the forming surface.

[0168] Then, except for a portion of the samples, heat treatment prior to finishing was performed under the conditions described in Tables 3 and 4.

[0169] Subsequently, under the conditions described in Tables 3 and 4, finishing was performed to produce a strip with a width of approximately 60 mm and the thickness shown in Tables 5 and 6 for performance evaluation.

[0170] The strip used to evaluate the obtained characteristics was evaluated in the following manner.

[0171] (Composition Analysis)

[0172] Samples were collected from the obtained ingots for analysis. Mg was determined by inductively coupled plasma atomic emission spectrometry, and other elements were determined by glow discharge mass spectrometry (GD-MS).

[0173] In addition, the measurements were taken at both the center of the sample and at one end in the width direction, with the higher concentration at the location being recorded as the sample content. The results confirmed the composition shown in Tables 1 and 2.

[0174] (Conductivity)

[0175] Test pieces with a width of 10 mm and a length of 60 mm were collected from the strip used for characteristic evaluation, and the resistance was determined using the 4-terminal method. Furthermore, the dimensions of the test pieces were measured using a micrometer, and the volume of the test pieces was calculated. Then, the conductivity was calculated based on the measured resistance value and volume. In addition, test pieces were collected with their length direction parallel to the rolling direction of the strip used for characteristic evaluation. The evaluation results are shown in Tables 5 and 6.

[0176] (Crystal Orientation)

[0177] The strip with a width of 20mm and a length of 20mm was cut from the obtained characteristic evaluation material. The surface perpendicular to the width direction of the roll, i.e., the TD (Tranverse Direction) surface, was embedded in the resin as the observation surface. After mechanical polishing with water-resistant sandpaper and diamond abrasive, it was finely polished with colloidal silica solution and used as the observation sample.

[0178] Subsequently, using a scanning electron microscope, electron beams were irradiated onto each measurement point (pixel) within the measurement range on the sample surface to obtain a pattern based on electron backscatter diffraction. Using a SEM-EBSD (Electron Backscatter Diffraction Patterns) measuring device, the orientation density and S-orientation ratio were measured in the range of φ2=0°, φ1=0°~20°, and Φ=35°~55°, expressed in Euler angles (φ1, Φ, φ2), as follows.

[0179] The boundary between adjacent measurement points with an orientation difference of 15° or more is defined as a large-angle grain boundary. Twin boundaries are also considered large-angle grain boundaries. Furthermore, the measurement range is adjusted so that each sample contains more than 100 grains. Based on the obtained orientation analysis results, a grain boundary map is constructed using large-angle grain boundaries. Following the cutting method of JIS H 0501, five line segments of specified lengths are drawn on the grain boundary map. The number of grains that can be completely cut is counted, and the sum of their cutting lengths (the lengths of the line segments cut at the grain boundary) is divided by the number of grains to calculate the average value, i.e., the average grain size.

[0180] Next, the observation surface was measured using the EBSD method at intervals less than one-tenth of the calculated average crystal grain size. The total area was 10,000 μm across multiple fields of view, encompassing more than 1,000 grains. 2 Within the measured area, the CI (Confidence Index) value of each measurement point was obtained by analyzing the measurement results using the OIM data analysis software. Measurement points with a CI value below 0.1 were excluded, and texture analysis was performed using the OIM data analysis software to obtain the S-orientation ratio and crystal orientation distribution function.

[0181] The crystal orientation distribution function obtained through analysis is displayed using Euler angles. The obtained S-orientation ratios and the average values ​​of orientation densities within the ranges of φ2 = 0°, φ1 = 0°–20°, and Φ = 35°–55° are shown in Tables 5 and 6. Additionally, in Tables 5 and 6, the average values ​​of orientation densities within the ranges of φ2 = 0°, φ1 = 0°–20°, and Φ = 35°–55° are recorded in the "ODF" column.

[0182] (Heat resistance temperature)

[0183] Regarding the heat resistance temperature, according to JCBA T325:2013 of the Japan Copper and Brass Association, isochronous softening curves based on Vickers hardness after 1 hour of heat treatment were obtained, and the heating temperature at which the hardness reaches 80% of the original hardness was determined for evaluation. Furthermore, the Vickers hardness was measured on the rolled surface. The evaluation results are shown in Tables 5 and 6.

[0184] [Table 1]

[0185]

[0186] [Table 2]

[0187]

[0188] [Table 3]

[0189]

[0190] [Table 4]

[0191]

[0192] [Table 5]

[0193]

[0194] [Table 6]

[0195]

[0196] In Comparative Example 1, the heat resistance temperature was lower and the heat resistance was insufficient because the Mg content was less than that of the present invention.

[0197] In Comparative Example 2, the Mg content exceeded the scope of the present invention, resulting in lower conductivity.

[0198] In Comparative Example 3, the total content of S, P, Se, Te, Sb, Bi and As exceeded 30 ppm by mass, the heat resistance temperature was low, and the heat resistance was insufficient.

[0199] In Comparative Example 4, the mass ratio of [Mg] / [S+P+Se+Te+Sb+Bi+As] was less than 0.6, resulting in a lower heat resistance temperature and insufficient heat resistance.

[0200] In Comparative Example 5, the average value of the orientation density in the range of φ2=0°, φ1=0°~20°, and Φ=35°~55° was less than 1.3, indicating a low heat resistance temperature and insufficient heat resistance.

[0201] In Comparative Example 6, the area ratio of crystals with a crystal orientation within 10° relative to the S orientation {123}<634> exceeded 10%, resulting in a lower heat resistance temperature and insufficient heat resistance.

[0202] In contrast, in Examples 1 to 24 of the present invention, it was confirmed that conductivity and heat resistance were improved in a balanced manner.

[0203] Based on the above, it is confirmed that, according to the present invention, a copper alloy with high electrical conductivity and excellent heat resistance can be provided.

[0204] Industrial availability

[0205] It can provide copper alloys, copper alloy ductile materials, electronic and electrical equipment components, terminals, busbars, lead frames, and heat dissipation substrates with high conductivity and excellent heat resistance.

[0206] Symbol Explanation

[0207] 10 Copper Alloy Plastic Processing Materials

[0208] 11thick part

[0209] 12 Thin section

[0210] Thickness of t1 thick part 11

[0211] Thickness of t2 thin part 12

Claims

1. A copper alloy, characterized in that, The copper alloy has a composition of Mg content exceeding 10 ppm by mass and below 100 ppm by mass, with the remainder being Cu and unavoidable impurities. Among the unavoidable impurities, the content of S is below 10 ppm by mass, the content of P is below 10 ppm by mass, the content of Se is below 5 ppm by mass, the content of Te is below 5 ppm by mass, the content of Sb is below 5 ppm by mass, the content of Bi is below 5 ppm by mass, and the content of As is below 5 ppm by mass. Furthermore, the total content of S, P, Se, Te, Sb, Bi, and As is below 30 ppm by mass. When the content of Mg is defined as [Mg], and the total content of S, P, Se, Te, Sb, Bi, and As is defined as [S+P+Se+Te+Sb+Bi+As], their mass ratio [Mg] / [S+P+Se+Te+Sb+Bi+As] is within the range of 0.6 or higher and 50 or lower. The conductivity is above 97% IACS. When the crystal orientation distribution function obtained by texture analysis based on the EBSD method is expressed in Euler angles, the average orientation density in the ranges of φ2=0°, φ1=0°~20°, and Φ=35°~55° is greater than 1.3 and less than 20.

0. The area ratio of crystals with a crystal orientation within 10° relative to the S orientation {123}<634> is less than 10%.

2. The copper alloy according to claim 1, characterized in that, The content of Ag is in the range of 5 ppm by mass and 20 ppm by mass.

3. The copper alloy according to claim 1 or 2, characterized in that, It has a heat resistance temperature of over 260℃.

4. A copper alloy ductile material, characterized in that, The copper alloy ductile material is composed of any one of the copper alloys described in claims 1 to 3.

5. The copper alloy ductile material according to claim 4, characterized in that, The copper alloy plastic processing material is a shaped strip.

6. The copper alloy ductile material according to claim 4 or 5, characterized in that, The surface of the copper alloy plastic processing material has a metal coating.

7. A component for electronic and electrical equipment, characterized in that, The electronic and electrical equipment components are made of copper alloy plastic-processed material as described in any one of claims 4 to 6.

8. A terminal, characterized in that, The terminal is made of a copper alloy ductile material as described in any one of claims 4 to 6.

9. A busbar, characterized in that, The busbar is made of a copper alloy ductile material as described in any one of claims 4 to 6.

10. A lead frame, characterized in that, The lead frame is made of copper alloy ductile material as described in any one of claims 4 to 6.

11. A heat dissipation substrate, characterized in that, The heat dissipation substrate is made of copper alloy plastic processing material as described in any one of claims 4 to 6.

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