KR20130093469A - Cu-ag alloy wire and method for producing cu-ag alloy wire - Google Patents

Abstract

Provided is a Cu-Ag alloy wire having high electrical conductivity and high strength, and a method for producing the Cu-Ag alloy wire. As a Cu-Ag alloy wire which consists of a copper alloy containing Ag, Ag is contained 0.1 mass% or more and 15 mass% or less, and remainder consists of Cu and an impurity. When an arbitrary observation field is taken within 1000 nm x 1000 nm in the cross section of this Cu-Ag alloy wire, the area ratio of the crystallization deposit whose maximum length of the straight line which cuts a crystallization precipitate among the crystallization of Ag which exists in this observation field is 100 nm or less. This is over 40%. The very fine granular Ag is dispersed and present uniformly, so that the dispersion can be strengthened, thereby not only improving the strength but also having a high electrical conductivity.

Description

Cu-Ag alloy wire and manufacturing method of Cu-Ag alloy wire {Cu-Ag ALLOY WIRE AND METHOD FOR PRODUCING Cu-Ag ALLOY WIRE}

The present invention relates to a coaxial cable having a Cu-Ag alloy wire, a center conductor made of the Cu-Ag alloy wire, a coaxial cable bundle in which a plurality of coaxial cables are bundled, and a method for producing a Cu-Ag alloy wire. In particular, it is related with Cu-Ag alloy wire which has high electrical conductivity and is higher in strength.

With the miniaturization and weight reduction of various electric and electronic devices such as electronic devices and medical devices, further thinning of wires used for these electric and electronic devices is desired.

Even with a small diameter, it satisfies the strength and fatigue characteristics (resistance to bending, salting, etc.) required for the electric wire, and also has workability (fresh wire, stranded wire, transverse winding, etc.). In order to improve the workability in processing), the conductor material of the electric wire is required to be excellent in breaking strength. Conventionally, although a copper wire has been used as a conductor of the electric wire, a copper wire has a low breaking strength, for example, when it is made into an ultrafine wire of 0.1 mm (100 μm) or less, it is disconnected when stress caused by repeated bending or salting is applied. easy.

As one of the methods of improving the breaking strength of a conductor material, adding and alloying an element is mentioned. For example, Patent Document 1 discloses a Cu-Ag alloy wire containing Ag.

Japanese Patent Laid-Open No. 2001-040439

In general, the copper alloy can increase the strength, such as breaking strength, by increasing the additive element, while the electrical conductivity is lowered. Since electric resistance is desired to be small for the electric wire used for an electronic device, a medical device, etc., when the wire material with low electrical conductivity is used for a conductor, it is necessary to enlarge a conductor cross-sectional area and to reduce electric resistance. In this case, it is difficult to achieve small hardening. Therefore, even if it is a narrow diameter, development of the wire rod which has high electrical conductivity and is higher in strength is desired.

Then, one of the objectives of this invention is providing the Cu-Ag alloy wire which has high electrical conductivity and is still high. Moreover, another object of this invention is to provide the manufacturing method of the said Cu-Ag alloy wire. Further, another object of the present invention is to provide a coaxial cable having a center conductor made of the Cu-Ag alloy wire, and a coaxial cable bundle in which a plurality of coaxial cables are bundled.

[Cu-Ag alloy wire]

MEANS TO SOLVE THE PROBLEM The present inventors selected Ag as an addition element which is hard to fall comparatively and is effective in the strength improvement, and targets a Cu-Ag alloy wire, and has high electrical conductivity equivalent or more than a conventional Cu-Ag alloy wire. The Cu-Ag alloy wire with higher strength was examined in various ways. As a result, since Ag exists in a very fine granular form, the knowledge that a Cu-Ag alloy wire with high electrical conductivity and improved strength was obtained. This invention is based on the said knowledge.

The Cu-Ag alloy wire of this invention relates to the wire rod which consists of a copper alloy containing Ag. This Cu-Ag alloy wire contains Ag by 0.1 mass% or more and 15 mass% or less, and remainder consists of Cu and an impurity. And in this Cu-Ag alloy wire, when the arbitrary observation visual field is taken within 1000 nm x 1000 nm in the cross section of the said Cu-Ag alloy wire, the crystallization precipitate among the crystallization of Ag which exists in this observation visual field. It is characterized in that the area ratio of the crystallized precipitate having a maximum length of the straight line cutting 100 mm or less is 40% or more.

In the Cu-Ag alloy wire of the present invention, by dispersing and dispersing very fine granular Ag uniformly, not only can the dispersion strengthening be achieved, but also the strength can be further improved, and the electrical conductivity can be high.

As one form of the Cu-Ag alloy wire of this invention, the crystallite of the said Ag further mentions that fibrous precipitate is contained.

By crystallization of Ag as a fibrous precipitate, fiber reinforcement can be achieved. The Cu-Ag alloy wire of the above aspect can achieve further improvement in strength by precipitation precipitation strengthening of Ag by a mixed structure of fiber reinforcement and dispersion reinforcement described above.

The Cu-Ag alloy wire of the present invention can be used for a center conductor of a coaxial cable. The coaxial cable of the present invention relates to a coaxial cable having a center conductor having one or more element wires, an insulator covering the periphery of the center conductor, and an outer conductor disposed around the insulator. In this coaxial cable, the said element wire is a Cu-Ag alloy wire of the said invention, It is characterized by the above-mentioned.

Then, a plurality of coaxial cables of the present invention can be bundled to obtain a coaxial cable bundle of the present invention.

The coaxial cable of the present invention and the coaxial cable bundle of the present invention can improve the strength (fatigue characteristics) due to precipitation strengthening by using the Cu—Ag alloy wire of the present invention as a center conductor.

[Manufacturing method of Cu-Ag alloy wire]

MEANS TO SOLVE THE PROBLEM The present inventors selected Ag as an addition element which is hard to fall comparatively and is effective in the strength improvement, and targets a Cu-Ag alloy wire, and has high electrical conductivity equivalent or more than a conventional Cu-Ag alloy wire. In the meantime, various methods for improving the strength were examined. As a result, while making content of Ag into a specific range and devising a manufacturing method, the knowledge that the Cu-Ag alloy wire with high electrical conductivity and improved strength was obtained. More specifically, before carrying out a wire drawing process, it has a process of forming the state which fully solidified Ag in Cu, and performs Ag specific-treatment to the wire material by which the wire processing is given, and deposits Ag, and is mentioned above. It has been found that wire rods with higher strength can be obtained while having an equivalent conductivity as compared with the case where no step is employed to obtain a solid solution. The Cu-Ag alloy wire of this invention mentioned above can be manufactured by the manufacturing method of the Cu-Ag alloy wire of this invention mentioned later.

Here, in the Cu-Ag alloy containing a certain amount of Ag, the conductivity decreases as Ag is dissolved in Cu, and the conductivity increases as Ag precipitates. Therefore, in the Cu-Ag alloy containing a certain amount of Ag, the term "form a state in which Ag is sufficiently dissolved in Cu" means that the conductivity is lower than that in which Ag precipitates to increase the conductivity. .

In addition, a state where much Ag is precipitated is likely to be formed before casting, typically during casting (especially when the cooling rate is slow).

From the above, it is proposed to sufficiently dissolve Ag before wire drawing, and to use the electrical conductivity as an index indicating the state in which Ag is dissolved in Cu.

The manufacturing method of the Cu-Ag alloy wire of this invention relates to the method of producing a wire rod by carrying out wire drawing to the casting material which consists of a copper alloy containing Ag. In this manufacturing method, when the Ag content is x (mass%) (0.1 mass%? X? 15 mass%), the conductivity C (% IACS) of the material is used as the material before the wire drawing. Forms a solid solution material satisfying C ≦ (−0.1786) × x + 97. Moreover, in this manufacturing method, the wire rod to which the said wire drawing is performed is heat-processed at least 1 time whose heating temperature is 300 degreeC or more and holding time is 0.5 hour or more. The calculation method of the conditional expression concerning the said conductivity C: C <= (-0.1786) xx + 97 is mentioned later.

In the above production method, by forming a material in which Ag is sufficiently dissolved, providing this material for drawing, and performing the specific heat treatment on the wire which has been subjected to drawing, very fine granular Ag is precipitated, These Ag grains can be made into a structure in which the Ag particles are uniformly dispersed. By strengthening the dispersion by this fine grain Ag, the strength of a Cu-Ag alloy wire can be improved. In addition to this, Ag which precipitated before the wire drawing is stretched into a fibrous shape by drawing, thereby improving the strength by fiber reinforcement. It is thought that the Cu-Ag alloy wire with high electrical conductivity and strength can be produced by the presence of the ultrafine Ag dispersed uniformly, the presence of fibrous Ag, or both coexisting. As Cu-Ag alloy wire obtained by the manufacturing method of the said invention, Ag contains 0.1 mass% or more and 15 mass% or less, for example, remainder consists of Cu and an impurity, and a wire diameter is 1000 micrometers or less. .

The Cu-Ag alloy wire of the present invention has high electrical conductivity and high strength. The manufacturing method of the Cu-Ag alloy wire of this invention can manufacture the Cu-Ag alloy wire of high electrical conductivity and high strength.

1 is a graph showing the relationship between the content of Ag and the electrical conductivity in various Cu-Ag alloy materials produced with different manufacturing conditions.
FIG. 2 is a micrograph (500 times) of the wire rod (φ 2.6 mm) after heat treatment (precipitation heat treatment) is performed on the wire rod, and FIG. 2-3-2 and FIG. 2 (II) show sample No. 2-4-2.
Fig. 3 is a transmission electron micrograph (150000 times) of the wire rod (φ 0.9 mm) after heat treatment (precipitation heat treatment) is performed on the wire rod, and Fig. 3 (I) shows the sample No. 2-3, FIG. 3 (II) shows Sample No. 2-4 and FIG. 3 (III) show Sample No. 2-110 is represented.
It is a schematic diagram explaining the crystallization of Ag which exists in the micrograph of FIG.
It is a schematic diagram explaining the structure which comprises this invention Cu-Ag alloy wire.
6 is a perspective view of a coaxial cable of the present invention.

Hereinafter, the present invention will be described more specifically.

[Cu-Ag alloy wire]

The Cu-Ag alloy which comprises the Cu-Ag alloy wire of this invention is a binary alloy whose content of Ag is 0.1 mass% or more and 15 mass% or less (residual Cu and an impurity). When Ag content is 0.1 mass% or more, the improvement effect of the strength by precipitation strengthening of Ag is easy to be acquired, and when it is 15 mass% or less, it is easy to suppress the fall of the electrical conductivity resulting from excessive precipitation of Ag. In particular, when the content of Ag is 1% by mass or more and 10% by mass or less, high strength and high electrical conductivity can be provided in a good balance, which is more preferable. Raw materials are prepared to have a predetermined composition. The raw material Cu or raw material Ag is high in purity, for example, having four or more nine nine classes (purity 99.99%) and less impurities. Particularly, the raw material Cu and raw material Ag may be involved in disconnection in the manufacture of thin wire. Residual foreign matter can be reduced.

When the content of Ag is small, fine Ag is apt to precipitate in the crystallization of Ag. Here, the magnitude | size of particulate Ag says that "the maximum length of the straight line which cut | disconnects a crystallization thing is 100 nm or less." In addition, the Ag crystal grains may contain granulated Ag, and the magnitude | size says that "the maximum length of the straight line which cuts a crystal grain is more than 100 nm." When Ag content increases, fibrous Ag precipitates as a crystallization of Ag. In this fibrous Ag, relatively large Ag of the precipitated Ag was extended. Especially when content of Ag is 2 mass% or more, this fibrous Ag becomes easy to confirm using a microscope. Most of the above crystallized precipitates are precipitates, and in particular, particulate Ag and fibrous Ag are considered to be substantially precipitates. And Ag of granulation is considered to be included as a crystallization part.

In the Cu-Ag alloy wire of the present invention, when an arbitrary observation field is taken within 1000 nm x 1000 nm in the cross section of the Cu-Ag alloy wire, the area ratio of fine Ag in the crystallites of Ag existing in this observation field is More than 40%. In the crystallization of Ag existing in the observation field, granulated Ag may exist in addition to fine Ag. Since fibrous Ag is large enough compared with the magnitude | size of an observation visual field, it is not included in "crystallization of Ag which exists in an observation visual field". The sampling method of this observation field is mentioned later. By making a structure in which fine Ag is uniformly dispersed, the strength can be improved by strengthening dispersion. Although Ag of granulation does not adversely affect the characteristic of a Cu-Ag alloy wire, it is thought that it does not contribute to a characteristic improvement.

In addition, when the content of Ag increases, the fibrous Ag is present in addition to the particulate Ag, whereby the strength by fiber reinforcement can be improved. It is thought that this Cu-Ag alloy wire is high in electrical conductivity and strength because the particulate Ag is uniformly dispersed, fibrous Ag is present, or both coexist.

The following method is considered as a method of contributing Ag of granulation to the improvement of the characteristic of a Cu-Ag alloy wire. Particularly large Ag in the granulated Ag can be improved in strength by fiber reinforcement by being stretched in a fibrous form at the time of drawing. Ag which is not fibrous in the granulated Ag can be dissolved into Cu by heat treatment and precipitated as fine particulate Ag as much as possible to achieve the solid solution, thereby improving the strength by strengthening dispersion. Thus, it is thought that the strength of the granulated Ag can be improved depending on whether the granulated Ag is fine or fibrous.

The said Cu-Ag alloy wire is typically a round wire of a cross-sectional circular shape, and the thing of various wire diameters is mentioned. The wire diameter of 3 mm or less, especially φ 1 mm (1000 µm) or less, can be a narrow wire, which is preferable. In addition, since the Cu-Ag alloy wire of the present invention has high electrical conductivity and high strength, it is expected that the Cu-Ag alloy wire can be sufficiently used for conductors of electric wires, not only stranded wires that are twisted together with fine wires. By suitably changing the workability at the time of drawing, it can also be set as the ultrafine Cu-Ag alloy wire whose wire diameter is 0.01 mm (10 micrometers)-0.08 mm (80 micrometers).

The Cu-Ag alloy wire of the present invention has high electrical conductivity, high strength, and also depends on the wire diameter and content of Ag. For example, the Cu-Ag alloy wire is an ultrafine Cu-Ag alloy wire having a wire diameter of 0.05 mm (50 µm) or less, and has a conductivity of 70. The form which satisfy | fills% IACS or more and tensile strength more than 1200 MPa, or the form which is a Cu-Ag alloy wire whose wire diameter is 1 mm-3 mm of wire diameter, and whose electrical conductivity meets 95% IACS or more and tensile strength is 300 MPa or more is mentioned, for example. Can be.

In addition, the Cu-Ag alloy wire of this invention can be made into the form provided with the plating layer which consists of Ag, Ag alloy, Sn, Sn alloy, etc. on the surface. By providing a plating layer, the wettability and corrosion resistance with a solder can be improved. When manufacturing the Cu-Ag alloy wire which has a plating layer, formation of a plating layer may be performed in the middle of wire drawing, and may be performed after final drawing.

[Coaxial Cables and Coaxial Cable Bundles]

As shown in FIG. 6, the coaxial cable 1 of this invention is arrange | positioned around the center conductor 11, the insulator 12 which covers the periphery of the said center conductor 11, and the said insulator 12 around. With an outer conductor 13. Moreover, the coaxial cable 1 is provided with the exterior 14 which covers the outer periphery of the outer conductor 13. The said center conductor 11 has one or more element wires, and this element wire is a Cu-Ag alloy wire of this invention, It is characterized by the above-mentioned. And the coaxial cable bundle of this invention can be obtained by bundle | bundling a plurality of said coaxial cables of this invention. By using the Cu-Ag alloy wire of this invention for the center conductor 11 of the coaxial cable 1, the strength (fatigue characteristic) by precipitation strengthening can be aimed at.

[Manufacturing method of Cu-Ag alloy wire]

The manufacturing method of the Cu-Ag alloy wire of this invention typically has the following casting process, the wire drawing process, and a heat treatment process.

Casting process: The process of manufacturing a casting material using the mixed melt which melt | dissolved Ag and Cu of a raw material.

Drawing process: The process of carrying out drawing process to the raw material which passed the said casting process, and producing the wire rod of final wire diameter.

Heat treatment process: The process of performing the specific heat processing mentioned later at least once to the wire rod material (including the wire rod of a final wire diameter) to which the said wire drawing process is performed.

In particular, a solid solution material in which Ag is sufficiently dissolved in Cu is prepared as the material to be used for drawing.

[Casting process]

Continuous casting can be used suitably for manufacture of the said casting material. The continuous casting is, for example, a form in which a long casting material is continuously produced by pinching and solidifying the solidification shell by pinch rolls (packing). The casting atmosphere may be an atmospheric atmosphere, but oxidation of the molten metal can be prevented by setting the atmosphere by an inert gas such as Ar. And as one form for forming the said solid solution material, what makes the cooling rate of the molten metal in this casting process into 8.5 degreeC / sec or more is mentioned. By setting the cooling rate at the time of casting to 8.5 degree-C / sec or more, ie, quenching, precipitation of Ag can be suppressed and the state which Ag fully dissolved can be formed. As the cooling rate is faster, precipitation of Ag can be suppressed, more preferably 10 ° C / sec or more. On the other hand, as mentioned above, when the solidification shell is stretched in order to increase the cooling rate, the solidification shell may not be sufficiently followed. Therefore, it is preferable to make the said cooling rate as large as possible in the range which a casting material manufactures continuously.

The cooling rate (° C./sec) at the time of casting is Tm (° C.) for the temperature just before pouring the mixed melt into the mold (for example, hot water in tundish), and Tc (° C. for the solidification start point). ), When the time taken for the mixed melt to move from the measurement point of temperature Tm to the measurement point of temperature Tc is t _mc (sec), the temperature difference: (Tm-Tc) divided by the time t _mc : (Tm-Tc) / Let t _mc .

In order to make the cooling rate at the time of casting into 8.5 degreeC / sec or more, for example, water cooling copper mold is used for a mold, or forced cooling so that the solidification shell drawn out from a mold can be cooled enough to surround the solidification shell drawn out. Arranging means. The forced cooling means may be, for example, a water-cooled copper block or a fan means that is a fan. By these means, the atmosphere around the solidification shell can be cooled, and the solidification shell is cooled by this cooled atmosphere. The cooling rate can be adjusted by appropriately adjusting the temperature of the forced cooling means, the extraction speed (casting speed) of the solidification shell, and the like.

Solvent Treatment

Or as one form for forming the said solid solution material, the solution treatment is carried out to the casting material obtained by the said casting process (it may be quenched above and may not be quenched above). . It is preferable that this solution treatment sets heating temperature to 600 degreeC or more, holding time for 0.5 hour or more, and cooling rate to 1.5 degreeC / sec or more.

By making heating temperature 600 degreeC or more and holding time 0.5 hours or more, Ag can be fully dissolved in Cu, even if Ag precipitates in a casting material. The higher the heating temperature tends to sufficiently dissolve Ag in Cu. However, if the heating temperature is too high, the Cu-Ag alloy starts to dissolve, so the heating temperature is preferably 850 ° C or lower. In addition, the longer the holding time, the more likely Ag can be solid-dissolved in Cu, and no particular upper limit is provided. However, it is preferable to appropriately select Ag in a range that does not cause a decrease in productivity.

By making the cooling rate at the time of the said solution into 1.5 degreeC / sec or more, ie, quenching, precipitation of solid solution Ag can be suppressed and the state which Ag fully dissolved can be formed. As the cooling rate in the solution treatment is faster, precipitation of Ag can be suppressed, more preferably 3 ° C / sec or more, and no upper limit is particularly provided.

The cooling rate (° C./sec) at the time of the solution treatment measures the temperature of the sample 1 minute after the start of cooling, and the temperature at this time is T ₁ (° C.) and the solution temperature is Tr (° C.). The temperature difference: (Tr-T ₁ ) is divided by the time: 60 seconds.

In order to make the cooling rate at the time of solution treatment into 1.5 degreeC / sec or more, forced cooling means can be used suitably. For example, direct cooling using a fluid refrigerant such as water, oil, sand, or the like, an air blow using a fan, or the like, or a water-cooled copper block can be used. Cooling by a water-cooled copper block can be performed by arrange | positioning a water-cooled copper block so that the circumference | surroundings of the wire rod drawn out from the heat processing furnace may be cooled, for example, and cooling the atmosphere around the said wire rod. The cooling rate can be adjusted by appropriately adjusting the refrigerant temperature, the arrangement state of the forced cooling means, the amount of refrigerant, the amount of air, and the like.

[Fresh process]

The wire drawing (typically cold) is performed over a plurality of passes until the final wire diameter is obtained. The workability of each pass may be appropriately adjusted in consideration of the composition (content of Ag), the final wire diameter, and the like.

[Heat treatment]

The wire rod subjected to drawing processing, specifically, the drawing material in the middle of drawing processing, or the drawing material drawn to the final wire diameter is heat-treated under specific conditions, and Ag is precipitated from the state which Ag fully dissolved. By this heat treatment, it is thought that extraneous Ag in a nano order precipitates. By dispersing and dispersing the ultrafine Ag uniformly, Cu-Ag has higher strength even if the conductivity of Ag is the same and the electrical conductivity is about the same as that of the wire rod of the structure mainly containing fibrous Ag. It is thought that an alloy wire can be manufactured.

The heat treatment (hereinafter referred to as precipitation heat treatment) may be performed at least once on a wire rod subjected to drawing processing, and may be performed multiple times. In the case of one time of precipitation heat treatment, the production process is small and the productivity is excellent. In the case of multiple times of precipitation heat treatment, Ag precipitation, in particular, fine precipitation of Ag is increased to increase the strength and conductivity, or is introduced by drawing. It is possible to improve the electrical conductivity by removing the work deformation, or to facilitate the subsequent drawing processing.

The precipitation heat treatment conditions are set at a heating temperature of 300 ° C. or higher and a holding time of 0.5 hour or longer. If the heating temperature is less than 300 ° C. and the holding time is less than 0.5 hour, Ag cannot be sufficiently precipitated or the work strain cannot be sufficiently removed. The higher the heating temperature and the longer the holding time, the easier it is to precipitate Ag. For example, when the temperature is higher than 600 ° C, the conductivity decreases due to the solid solution of Ag in Cu. Therefore, as for heating temperature, 600 degreeC or less, especially 350 degreeC or more and 550 degrees C or less, 400 degreeC or more and 450 degrees C or less are preferable, and the holding time of 0.5 hours or more and 10 hours or less is preferable. The cooling at the time of precipitation heat treatment is, for example, a furnace cooling that is left in a heat treatment furnace and cooled by natural cooling.

(Test Example 1)

Cu-Ag alloy material was manufactured on various conditions, and the relationship between Ag content and electrical conductivity was investigated. The results are shown in Figure 1 and Table 1.

The Cu-Ag alloy material was produced as follows. As raw material Cu, an electrolytic copper having a purity of 99.99% or more and silver granules (Ag) having a purity of 99.99% or more as a raw material Ag are prepared, charged into a crucible made of high purity carbon, and vacuum-dissolved in a continuous casting apparatus to dissolve Cu and Ag. Mixed melt was produced. As shown in FIG. 1 and Table 1, the addition amount of silver granules was adjusted so that Ag content (concentration) with respect to the molten metal might be 0.1 mass%-15 mass%.

By continuous casting using the obtained molten metal and a high-purity carbon mold, a cast material having a cross-sectional circular shape having a wire diameter of 8.0 mm was produced. In FIG. 1, the sample (casting (slow cooling)) shown by ▲ is a sample which made the cooling rate at the time of casting into 1.5 degreeC / sec (less than 8.5 degreeC / sec) by natural cooling, and shows the sample (casting (quenching) )) Is a sample in which forced cooling means such as water-cooled copper is arranged so as to surround the solidification shell drawn out from the mold, and the cooling rate is 10 ° C / sec (8.5 ° C / sec or more), and the sample represented by ◆ (Solution treatment material) is a solution treatment of 760 占 폚 x 2 hours, cooling rate: 9 占 폚 / sec (1.5 占 폚 / sec or more) to the casting material indicated by ▲ (cooling rate at the time of casting: 2.5 占 폚 / sec). This is a sample.

As shown in Table 1 and Fig. 1, even if the content of Ag is the same, it can be seen that the conductivity varies depending on the production conditions. Specifically, when the Ag content is the same, the conductivity is lower than that in the case of (1) the faster cooling rate at the time of casting, and (2) even if the cooling rate at the time of casting is lowered, the solution treatment is performed after casting. It turns out that an electrical conductivity becomes low when it implements. The reason why the electrical conductivity is lowered in this way is that the cooling rate during casting is increased or the solution treatment is performed after casting, and it is considered that Ag is in a solid solution of Cu. For this reason, it can be said that the electrical conductivity at the time of the cooling rate at the time of the said casting is used as a threshold as an index which shows the "state in which Ag is solid solution in Cu".

Hence, a formula that approximates the relationship between the content of Ag and the electrical conductivity when the cooling rate is low is considered. From the data shown in FIG. 1, the electrical conductivity when the cooling rate at the time of the said casting is low is grasped | ascertained by the linear function which makes Ag content into a variable. Therefore, if the approximation of the conductivity when the cooling rate at the time of casting is low is obtained using commercially available table calculation software Microsoft Corporation "Excel", the content of Ag is x (mass%) and the conductivity is C. At that time, C = (-0.1786) x x + 97 is obtained. Using this approximation formula, the "state in which Ag is dissolved in Cu" means a state having a conductivity equal to or less than the conductivity when the cooling rate at the time of casting is low, that is, the conductivity C (% IACS) is C≤. It can be said that it satisfies (-0.1786) xx + 97.

(Test Example 2)

The raw material which consists of Cu-Ag alloy was manufactured on various conditions, this material was wire-processed and heat-treated suitably, the Cu-Ag alloy wire was produced, and the electrical conductivity (% IACS) and tensile strength (MPa) were investigated.

Each sample was produced as follows. A raw material similar to Test Example 1 was prepared, and a mixed molten metal of Cu and Ag was prepared so that the Ag content (concentration) became the amount shown in Table 2, and the cross section having a wire diameter of 8.0 mm by continuous casting as in Test Example 1. A circular cast material was produced. Each casting material changed the cooling conditions at the time of casting so that it might become the cooling rate shown in Table 2. The sample whose cooling rate is less than 8.5 degree-C / sec is a sample by natural cooling. Samples having a cooling rate of 8.5 ° C./sec or more are arranged by arranging a water-cooled copper block to surround the solidification shell drawn out from the mold to cool the surrounding atmosphere, or by arranging a fan to cool by an air blast. These samples were quenched by combining these forced cooling means, and the cooling rate at the time of casting was changed by adjusting the temperature, air volume, etc. of a water-cooled copper block suitably.

The sample (No. 2-1, 2-3, 2-3-2, 2-5, 2-7, 2-10, 2-12, 2-14) which described only the casting material in the manufacturing conditions column of Table 2, The final wire diameter obtained by performing wire drawing on the obtained casting material, performing intermediate heat treatment (precipitation heat treatment) under the conditions shown in Table 2 at the time of wire diameter shown in Table 2, and further performing wire drawing: φ 0.04 mm Wire rod (Cu-Ag alloy wire).

Samples in which casting materials and heat treatment conditions are described in the manufacturing conditions column of Table 2 (No. 2-2, 2-4, 2-4-2, 2-6, 2-8, 2-9, 2-11, 2-13 , 2-15) is subjected to a heat treatment after the heat treatment (solution treatment) under the heat treatment conditions shown in Table 2 to the obtained cast material, and during the wire diameter shown in Table 2, intermediate heat treatment under the conditions shown in Table 2 After the (precipitation heat treatment), the final wire diameter obtained by further drawing processing is a wire rod (Cu-Ag alloy wire) having a diameter of 0.04 mm. In the heat treatment (solvation treatment) conditions of Table 2, "quenching" means cooling by water cooling in the cooling process from a heating temperature.

Sample No. After performing heat treatment (solvation treatment) on the obtained casting material (wire diameter phi 8.0mm) on the conditions shown in Table 2, 2-100 is wire drawing, and at the time of wire diameters shown in Table 2, it is shown in Table 2 After the intermediate heat treatment under the conditions, the final wire diameter obtained by further drawing processing: a wire rod (Cu-Ag alloy wire) having a diameter of 0.04 mm. Sample No. 2-110 is obtained by subjecting the obtained casting material (wire diameter φ 8.0 mm) to the obtained cast material, after performing intermediate heat treatment under the conditions shown in Table 2 at the time of wire diameter shown in Table 2. Final wire diameter: wire rod (Cu-Ag alloy wire) having a diameter of 0.04 mm. Sample No. 2-120 is wired to a wire diameter of 6.6 mm without subjecting the obtained casting material (wire diameter φ 8.0 mm) to the wire diameter φ 6.6 mm, and the obtained wire material (wire diameter φ 6.6 mm) is shown in Table 2 below. After the heat treatment (solvation treatment) is performed under the conditions shown, the wire drawing is further carried out, and at the time of wire diameter shown in Table 2, after the intermediate heat treatment is carried out under the conditions shown in Table 2, the final result obtained by further drawing. Wire diameter: A wire (Cu-Ag alloy wire) having a diameter of 0.04 mm.

The conductivity (% IACS) was measured with respect to the obtained solution (line diameter φ 8.0mm) and the cast material (line diameter φ 8.0mm) and the solution treatment material (line diameter φ 8.0mm) subjected to the solution treatment. The results are shown in Table 2. In addition, the tensile strength (MPa) and the electrical conductivity (% IACS) at the wire diameter of φ 2.6 mm or φ 0.9 mm, which were subjected to the above heat treatment, were respectively measured for the Cu—Ag alloy wire subjected to the intermediate heat treatment (precipitation heat treatment). The results are shown in Table 2. In addition, the tensile strength (MPa) and the electrical conductivity (% IACS) were measured also about the wire of final wire diameter: phi 0.04mm. The results are shown in Table 2. Tensile strength was measured according to the provisions of JIS Z 2241 (1998) (marking distance GL: 10 mm). The electrical conductivity was measured by the bridge method.

As shown in Table 2, it turns out that there exists a tendency for intensity | strength to become high, so that there is much Ag content. In particular, the cooling rate at the time of casting is made into 8.5 degreeC / sec or more, or the solution treatment is performed for the casting material of specific conditions, and the solid solution which electric conductivity C (% IACS) satisfy | fills C <= (-0.1786) xx + 97 The sample No. which formed the raw material, wire-processed this solid-solution raw material, and performed specific heat processing (precipitation heat processing) further. Immediately after the heat treatment, 2-1 to 2-15 have high electrical conductivity while having a conductivity equal to or higher than that of the casting material (low cooling rate. Refer to casting (slow cooling) in Table 1). And the sample No. It can be seen that 2-1 to 2-15 are high strength even in the final wire diameter.

Moreover, the sample with the same content of Ag is compared. The sample No. 2 had a low cooling rate during casting, a low heating temperature during solution treatment, and a slow cooling rate. Sample No. 2-100 which is not only subjected to the solution treatment but also to a slow cooling rate at the time of casting. 2-110 is the sample No. manufactured by the said specific condition. Compared with 2-3, 2-4, 2-3-2, 2-4-2, even if the electrical conductivity after solution treatment is high, it is understood that immediately after the heat treatment during the drawing and any of the strength at the final wire diameter is low. Can be. In addition, the sample No. which does not use the raw material before drawing as a specific solid solution material is used. 2-120 is sample No. It can be seen that the strength is low compared to 2-4, 2-3-2, 2-4-2.

Sample No. obtained. About 2-3-2 and 2-4-2, the cross section was observed with a microscope (500 times), and what processed the observation image by image processing is shown in FIG. In Fig. 2, the elongated nu phase has elongated Ag. The size of this fibrous Ag is a micro order, and it turns out that it is about several tens of micrometers in length.

Next, Ag crystallization deposits are observed. If fibrous Ag can be confirmed in a micrograph, the sample for observation of Ag crystallization of Ag is taken in the location where the fibrous Ag does not exist. In order to remove a fibrous Ag, observation | observation sample is preferable to observe from a longitudinal cross section (cut surface along the wire direction of a Cu-Ag alloy wire). The crystallized precipitate of Ag can be confirmed by taking arbitrary observation visual fields within 1000 nm x 1000 nm from this observation sample, and observing with a transmission electron microscope.

3, sample No. The transmission electron microscope photograph (150000 times) of a cross section is shown about 2-3, 2-4, and 2-110. The observation field is an area of 440 nm x 326 nm. In the crystallization of Ag which exists in this observation visual field, the maximum length of the straight line which cut | disconnects a crystallization count was counted, and the total area of this grain was computed. The crystallized precipitate of Ag was made to measure the particle | grains contained in the whole in the observation visual field, and the particle | grains which were located in the outline of the observation visual field and partially fell out were measured. The schematic diagram explaining Ag which counted as fine grains among the crystallization of Ag which exists in the micrograph of FIG. 3 is shown in FIG. Ag enclosed by the circle shown by the dotted line in FIG. 4 is a particulate. In each said sample, Table 3 shows the total area of a crystallization deposit, the total area of a grain, the area ratio of the crystallization in an observation field, and the area ratio of the granules in a crystallization. In addition, sample No. It also shows in Table 3 also in 2-1 and 2-2.

Sample No. subjected to specific heat treatment 9 particle | grains existed in 2-3 and the observation visual field, and the area ratio of the particle | grains in a crystallization deposit was 68.9%. Moreover, sample No. which performed the solution treatment on the casting material. As for 2-4, all the crystallizations which exist in an observation visual field are fine particles, and the number of the fine particles is 23, and sample No. It precipitated much compared with 2-3. On the other hand, although the content of Ag was the same, the sample No. which not only performed the cooling rate at the time of casting but also performed the solution treatment. 2-110 is sample No. Compared with 2-3 and 2-4, there were few particle | grains which existed in the observation visual field, and the area ratio of the particle | grains in crystallization was 26.1%. Sample No. Sample No. containing more Ag than 2-3 and 2-4. Also in 2-1 and 2-2, the sample No. Results similar to 2-3 and 2-4 were obtained.

The schematic diagram explaining the structure which comprises the Cu-Ag alloy wire of this invention is shown in FIG. In the figure, the ellipsoid and the black circle in the rectangular frame represent Ag precipitated, and the white circle represents Ag dissolved. As one of the causes of the conductivity and tensile strength shown in Table 2, as shown in FIG. 2, the Ag is stretched and is in the form of fibers, and as shown in FIG. It is thought to be due to dispersion strengthening due to the existence of particles dispersed uniformly or to having a mixed structure of both. For example, as shown in Fig. 5, the mixed structure solidifies the cast material by solidifying the precipitated Ag, so that the high capacity of Ag is increased, and the solidified material is subjected to fresh processing. If it is carried out, Ag precipitated without solid solution at the time of the solution treatment is stretched by wire drawing to form a fibrous shape, and the above-described precipitation heat treatment is performed to form Ag in solid solution and precipitate in large quantities. I think. In contrast, for example, when the cooling rate during casting is low, a large amount of relatively large Ag precipitates, and as described above, the Ag is increased by drawing, but even when the above-described precipitation heat treatment is performed, granular Ag precipitates much. In general, only fibrous Ag exists. It is thought that the difference in strength occurred as described above due to the difference in the presence state of Ag.

In addition, it can be said from the test results that the samples subjected to the solution treatment under the conditions specified for the casting material tend to have higher strength than the samples having the cooling rate at the time of casting of 8.5 ° C / min or more. . In addition, it can be said that the specific heat treatment (precipitation heat treatment) to be performed in the middle of drawing is tended to increase in strength in the final wire diameter as the wire diameter is thicker. Further, even when the conductivity is the same after the specific heat treatment (precipitation heat treatment), it can be said that the faster the cooling rate at the time of formation of the solid solution material, the higher the strength is in both the heat treatment and the final wire diameter.

Based on the above test results, in the production of a Cu-Ag alloy wire containing a specific amount of Ag, as a material to be used for wire drawing, a solid material in which Ag is sufficiently dissolved is prepared, and wire drawing is performed. By performing the above-described precipitation heat treatment, it can be said that a wire rod having a higher strength can be obtained while having a conductivity higher than or equal to that of a conventional Cu-Ag alloy wire containing the same amount of Ag.

In addition, this invention is not limited to embodiment mentioned above, It is possible to change suitably, without deviating from the summary of this invention. For example, the content of Ag, the cooling rate at the time of casting, the conditions for the solution treatment (temperature, holding time, cooling rate), the wire diameter for performing the solution treatment or precipitation heat treatment, the conditions for the precipitation heat treatment (heating temperature, holding time), etc. Can be changed as appropriate.

The Cu-Ag alloy wire of the present invention is a conductor of various electronic and electronic devices such as portable electronic devices such as mobile phones, electronic devices mounted on automobiles, medical devices, industrial robots, and the like. Shielded conductor). The manufacturing method of the Cu-Ag alloy wire of this invention is high in electrical conductivity, and can be used suitably for manufacture of the said Cu-Ag alloy wire of high strength. The coaxial cable of this invention and the coaxial cable bundle of this invention can be used suitably for the power supply wiring of the said various electrical and electronic equipment.

1: coaxial cable
11: center conductor
12: Insulator
13: outer conductor
14: exterior

Claims (8)

As a Cu-Ag alloy wire which consists of a copper alloy containing Ag,
0.1 mass% or more and 15 mass% or less, and remainder consists of Cu and an impurity,
When an arbitrary observation field is taken within 1000 nm x 1000 nm in the cross section of the said Cu-Ag alloy wire, the area ratio of the crystallization precipitate of which the maximum length of the straight line which cuts a crystallization crystal among Ag crystals existing in this observation field is 100 nm or less. The Cu-Ag alloy wire, which is 40% or more. The method of claim 1,
The Cu-Ag alloy wire, wherein the crystallite of Ag contains fibrous precipitates. A coaxial cable comprising a center conductor having at least one element wire, an insulator covering the periphery of the center conductor, and an outer conductor disposed around the insulator,
Said element wire is a Cu-Ag alloy wire of Claim 1 or 2, The coaxial cable characterized by the above-mentioned. A coaxial cable bundle comprising a plurality of coaxial cables according to claim 3. As a manufacturing method of the Cu-Ag alloy wire which wire-processes the casting material which consists of a copper alloy containing Ag, and manufactures a wire rod,
When the content of Ag is x (mass%) (0.1 mass%? X? 15 mass%), the conductivity C (% IACS) of the material is C? (- 0.1786) × x + 97 to form a solid solution,
A method for producing a Cu-Ag alloy wire, wherein the wire rod subjected to the drawing is subjected to at least one heat treatment at a heating temperature of 300 ° C. or more and a holding time of 0.5 hours or more. The method of claim 5, wherein
The solid solution material is formed by performing a solution treatment on the cast material,
The solution treatment is a method for producing a Cu-Ag alloy wire, characterized in that the heating temperature is at least 600 ° C, the holding time is at least 0.5 hour, and the cooling rate is at least 1.5 ° C / sec. The method according to claim 5 or 6,
The said casting material is formed by making cooling rate of the molten metal in the casting process into 8.5 degreeC / sec or more, The manufacturing method of the Cu-Ag alloy wire characterized by the above-mentioned. It is obtained by the manufacturing method of the Cu-Ag alloy wire in any one of Claims 5-7,
0.1 mass% or more and 15 mass% or less, and remainder consists of Cu and an impurity,
The Cu-Ag alloy wire, whose wire diameter is 1000 micrometers or less.

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