KR101788497B1 - Copper alloy plate, and electronic component for large current applications and electronic component for heat dissipation applications each provided with same - Google Patents

Abstract

The copper alloy sheet of the present invention contains 0.01 to 0.50 mass% of at least one of Zr and Ti in total, the balance copper and inevitable impurities, and has an electrical conductivity of 70% IACS or more and a mechanical strength of 0.2 %, And the 0.2% proof stress σ (MPa) and the elongation percentage L (%) satisfy the relationship of σ / L ≤ 150.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a copper alloy plate, a high-current electronic component and a heat dissipation electronic component having the copper alloy plate,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy plate having excellent heat dissipation, conductivity, bending workability and drawability, and more particularly to a copper alloy plate for use in electronic parts such as a terminal, a connector, a relay, a switch, a socket, a bus bar and a lead frame, To a copper alloy plate suitable for use in heat-radiating parts used in computers and the like, and large-current parts used in electric vehicles, hybrid cars, and the like.

Electric and electronic devices such as smart phones, tablet PCs, and personal computers are provided with parts for obtaining electrical connections such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, and the like for dissipating heat Respectively.

In recent years, along with the miniaturization of smart phones, tablet PCs, and personal computers, there is a tendency that heat storage when electric power is supplied to liquid crystal parts or IC chips in electric or electronic devices. In a state where the heat storage is large, thermal damage to the IC chip or the base is large, so that heat dissipation of the heat dissipation part becomes a problem.

2. Description of the Related Art Austenitic stainless steel (SUS304) and pure aluminum have been mainly used for heat dissipation parts in electric and electronic devices such as smart phones, tablet PCs, and personal computers. For example, a heat dissipation component (liquid crystal frame) attached to a liquid crystal of a smartphone or a tablet PC is required to have strength as a structure and bending workability or drawing workability necessary for fixation to a liquid crystal in addition to high heat dissipation. In some cases, only the bending workability or the drawing workability is required depending on the heat dissipation parts to be used.

The austenitic stainless steel (SUS304) has good bendability and drawability, but has low thermal conductivity. To compensate for this, an expensive heat conductive sheet or the like is used in combination. Therefore, the unit price of the heat-radiating part is increased. On the other hand, in pure aluminum and aluminum alloy, bending property and drawing workability were good, but the thermal conductivity and strength as a structural body were not sufficient.

In electrical components such as terminals and connectors, the cross-sectional area of the copper alloy in the conductive parts tends to decrease. As the cross-sectional area becomes smaller, the heat generated from the copper alloy when energized increases. Particularly, electronic parts used in electric vehicles and hybrid electric vehicles, which have remarkable growth, have parts that allow a significantly high current to flow through connectors of the battery unit, and heat generation of the copper alloy in service becomes a problem. Therefore, in order to reduce the heat generation amount, the conductive material is required to have excellent conductivity, and excellent bending workability and drawing workability are also required so that it can cope with miniaturization and high functionality of parts.

It is known that the thermal conductivity and the conductivity are in a proportional relationship, and a material in which Zr or Ti is added to Cu as an alloy having a relatively high conductivity and strength is known. C15150 (0.02 mass% Zr-balance Cu), C18140 (0.1 mass% Zr-0.3 mass% Cr-Cu), and the like, which are high in conductivity and relatively high in strength, 0.02 mass% Si-balance Cu), C18145 (0.1 mass% Zr-0.2 mass% Cr-0.2 mass% Zn-balance Cu), C18070 (0.1 mass% Ti- 0.3 mass% Cr- 0.02 mass% Si- , And C18080 (0.06 mass% Ti-0.5 mass% Cr-0.1 mass% Ag-0.08 mass% Fe-0.06 mass% Si-balance Cu) are registered in CDA (Copper Development Association).

However, although the copper alloy (Cu-Zr-Ti alloy) in which Zr or Ti is added to the conventional Cu is high in strength and heat conductivity, it is difficult to obtain the required bending workability or drawing workability, Did not satisfy.

Therefore, it can be said that it is industrially very significant to improve the bending workability and drawing workability while maintaining the required high strength and electric conductivity in the Cu-Zr-Ti alloy.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a copper alloy plate having high strength and conductivity, excellent bending workability and drawing processability, an electronic component for a large current and a heat dissipation electronic component having the same, And to improve the drawing processability of a Cu-Zr-Ti alloy having excellent strength.

The inventors of the present invention have found that, in a Cu-Zr-Ti alloy, the bending workability and drawing workability are improved by adjusting the metal structure with the elongation as an index and controlling the orientation of the crystal grains oriented on the rolled surface. And, based on the above findings, the following inventions were completed.

The copper alloy sheet of the present invention contains 0.01 to 0.50% by mass, preferably 0.015 to 0.3% by mass of one or both of Zr and Ti, the balance of copper and inevitable impurities, And a 0.2% proof stress σ (MPa) and an elongation percentage L (%) satisfy the relation of? / L? 150.

In the copper alloy sheet of the present invention, the X-ray diffraction integral intensity of the {220} plane obtained in the thickness direction on the rolled surface is I {220} using X-ray diffractometry and {220 of the pure copper powder standard sample }, the X-ray diffraction integral intensity from the surface when the I ⁰ {220}, it is preferable that the ^{I {220} / I 0 {} 220} ≥ 4.0.

In the copper alloy sheet of the present invention, the ratio of the minimum bending radius (MBR) to the plate thickness (t) in the rolling parallel direction (GW direction) and the rolling perpendicular direction (BW direction) / t < / = 2.0.

In addition, in the copper alloy sheet of the present invention, it is preferable that the Ericksen value / plate thickness in the Ericsen test is given as 0.5 or more.

The large current electronic component of the present invention comprises any of the copper alloy plates described above. Further, the heat dissipation electronic component of the present invention comprises any of the above-described copper alloy plates.

According to the present invention, it is possible to provide a copper alloy plate having high strength, high electrical conductivity, excellent bending workability and drawing workability. This copper alloy plate can be preferably used as a material for electronic parts such as terminals, connectors, switches, sockets, relays, bus bars, lead frames, and heat sinks, and can be suitably used for heat dissipation parts used in smart phones and personal computers, The present invention relates to a copper alloy plate suitable for use as a high current component used in a hybrid automobile or the like.

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

(characteristic)

The copper alloy sheet according to one embodiment of the present invention is characterized in that the copper alloy sheet has a conductivity of 70% IACS or more, 0.2% proof stress of 350 MPa or more, 0.2% proof stress / elongation (sigma / . Copper alloy plates having such characteristics are preferable for use in heat dissipation electronic parts.

(Alloy component concentration)

The Cu-Zr-Ti alloy sheet according to the embodiment of the present invention contains 0.01 to 0.50 mass% in total of one or both of Zr and Ti, and the total content of Zr and Ti is preferably 0.015 to 0.3% by mass, and more preferably 0.02 to 0.20% by mass. When the total of one or both of Zr and Ti is less than 0.01% by mass, it becomes difficult to obtain a tensile strength of 350 MPa or more. If the total of one or both of Zr and Ti exceeds 0.5% by mass, it becomes difficult to manufacture an alloy by hot rolling cracking or the like. When Zr is added, the addition amount is preferably adjusted to 0.01 to 0.45 mass%, and when Ti is added, the addition amount is preferably adjusted to 0.01 to 0.20 mass%. If the addition amount is less than the lower limit value, the 0.2% proof stress becomes less than 350 MPa. If the addition amount exceeds the upper limit value, the conductivity and the productivity may be deteriorated.

In order to improve the strength and the heat resistance, the Cu-Zr-Ti alloy sheet contains at least one of Ag, Co, Ni, Cr, Mn, Zn, Mg, Si, Fe, Sn and B in a total amount of not more than 2.0% . However, if the addition amount is too large, the conductivity may be lowered and the composition may be lowered to 70% IACS or the alloy composition may be deteriorated. Therefore, the addition amount is preferably 1.0 mass% or less, more preferably 0.5 mass% Or less. In order to obtain the effect of addition, it is preferable that the addition amount is 0.001 mass% or more in total amount.

(thickness)

The thickness of the product, that is, the plate thickness t, is preferably 0.05 to 2.0 mm. If the thickness is excessively small, sufficient heat radiation property can not be obtained, which is not suitable as a material for heat dissipation electronic parts. On the other hand, if the thickness is excessively large, bending and drawing processing become difficult. From this viewpoint, the more preferable thickness is 0.08 to 1.5 mm. When the thickness is within the above range, bending workability and drawing workability can be improved while suppressing the heat accumulation.

(Conductivity)

In the present invention, the conductivity measured according to JIS H 0505 is 70% IACS or more. When the conductivity is 70% IACS or more, the thermal conductivity is good and good heat dissipation can be ensured. More preferably, it is at least 75% IACS.

(0.2% proof)

In the present invention, the 0.2% proof stress of the copper alloy sheet is set to 350 MPa or more. According to this, it can be said that the copper alloy sheet has the necessary strength as the material of the structural material.

(Elongation)

It is more preferable to satisfy the relationship of sigma / L ≤ 100, more preferably, the relation of sigma / L ≤ 100 when the elongation (El) of the product is L (%) and the 0.2% proof stress (YS) The drawing processability and the bendability are improved. If the 0.2% proof stress / elongation is 150 or less, it can be said that it has necessary drawing processability. When? / L > 150, drawability and bendability are deteriorated. On the other hand, it is preferable that the lower limit value of? / L is 30. If? / L is small, it is feared that the 0.2% proof stress will not satisfy 350 MPa. Although the upper limit value of the elongation L is not particularly restricted, when the value exceeds 15%, the strength is lowered, and in some cases, the 0.2% proof may be lower than 350 MPa. Therefore, in a preferred embodiment, the elongation L is 15% or less.

The term "elongation ratio" as used herein refers to "elongation at break" defined in JIS Z 2241, and "elongation percentage" and "0.2% proof stress" refer to the tensile elongation of the specimen in accordance with JIS Z 2241 Measurement shall be made by tensile test.

(Bending workability)

The evaluation of the bending workability of the present invention is carried out by a W bending test (JIS H 3130) using a test piece of a desk having a width of 10 mm and a length of 30 mm. The test specimen collection direction is evaluated by the ratio of the minimum bend radius (MBR) and the plate thickness t (MBR / t), in which the cracks do not occur, in the rolling parallel direction (GW) and in the direction perpendicular to the rolling direction (BW). The ratio (MBR / t) of the minimum bending radius (MBR) is preferably 2.0 or less from the viewpoint of ensuring good bendability. A more preferable range of MBR / t is 1.8 or less.

(Drawing processability)

In the copper alloy sheet of the present invention, it is preferable that the ratio of the Erichen value measured by the Ericsen test based on JIS Z 2247 to the sheet thickness is 0.5 or more. When the erichen value / plate thickness is 0.5 or more, there is practically no problem in drawing workability. On the other hand, the erichen value / plate thickness is preferably 1.5 or less. If it exceeds 1.5, the 0.2% proof stress is likely to be less than 350 MPa. More preferably, the Ericksen value / plate thickness is in the range of 0.5 to 1.2.

(Crystal orientation)

The X-ray diffraction integral intensity from the {220} plane of the pure copper powder standard sample was determined as I {220} by using the X-ray diffraction method and the X-ray diffraction integral intensity of the {220} When I {220} / I ⁰ {220} is 4.0 or more when the intensity is I ⁰ {220}, the drawing processability is improved. When I {220} / I ⁰ {220} is less than 4.0, drawability is deteriorated because development of texture is small. The upper limit is not particularly formed, but it is more preferable that I {220} / I ⁰ {220} is 4.0 to 7.0. Also, the standard sample of pure copper powder is defined as a copper powder having a purity of 325 mesh (JIS Z 8801) of 99.5%.

Hereinafter, an example of a preferable method for producing a copper alloy sheet according to the present invention will be described.

Copper or the like is dissolved as pure copper raw material, and Zr, Ti and other alloying elements are added as necessary, and the ingot is cast with a thickness of about 30 to 300 mm. This ingot is formed into a plate having a thickness of about 3 to 30 mm by, for example, hot rolling at 800 to 1000 DEG C, and then cold rolling and recrystallization annealing are repeated, and the final ingot is finished to a predetermined thickness by cold rolling, Deformation removal annealing is performed. The elongation after the final cold rolling is as low as not to exceed 2%, but is increased by subsequent deformation-removing annealing.

In the recrystallization annealing, part or all of the rolled structure is recrystallized. Further, by annealing under suitable conditions, Zr, Ti, and the like are precipitated and the conductivity of the alloy increases. In recrystallization annealing before the final cold rolling, the average crystal grain diameter of the copper alloy sheet is adjusted to 50 mu m or less. If the average crystal grain diameter is too large, it becomes difficult to adjust the 0.2% proof stress to 350 MPa or more.

The conditions of the recrystallization annealing before the final cold rolling are determined based on the target crystal diameter after annealing and the conductivity of the target product. Specifically, annealing may be carried out by using a batch furnace or a continuous annealing furnace at a furnace temperature of 350 to 800 占 폚. In the batch furnace, the heating time may be appropriately adjusted within the range of 30 minutes to 30 hours at the furnace temperature of 350 to 600 占 폚. In the continuous annealing furnace, the heating time may be appropriately adjusted within a range of 5 seconds to 10 minutes at a furnace temperature of 450 to 800 ° C. Generally, when annealing is performed at a lower temperature for a longer time, a higher conductivity is obtained at the same crystal grain diameter.

In the final cold rolling, the material is repeatedly passed between the pair of rolling rolls to finish with the target plate thickness. Here, the total processing of the final cold rolling and the degree of processing per pass are controlled.

The total machinability R (%) is given by R = (t ₀ - t) / t ₀ x 100 (t ₀ : plate thickness before final cold rolling, t: plate thickness after final cold rolling). R = (T ₀ - T) / T ₀ × 100 (T ₀ : Thickness before passing the rolling roll, T: thickness after passing through the rolling roll).

The total processing degree R is 40 to 99%, preferably 45 to 98.5%, more preferably 50 to 98%. If the total working degree R is too small, it is difficult to adjust the 0.2% proof stress to 350 MPa or more, and it becomes difficult to adjust I {220} / I ⁰ {220} to 4.0 or more. If the total processing degree R is excessively large, the edge of the rolled material may be cracked.

The processing ratio r per one pass should be 15% or more. If the machining radius r is too small, I {220} / I ⁰ {220} is reduced. If the entire path includes any one path having a machining radius r of less than 15%, I {220} / I ⁰ {220} It becomes difficult to adjust it. The upper limit of the processing degree r is not particularly limited, but it is preferably less than 40% in consideration of the control of the plate thickness accuracy by rolling.

The deformation-removing annealing of the present invention is carried out using a continuous annealing furnace capable of holding a copper alloy sheet in a plate in a furnace. In the case of a batch furnace, since the material is heated in a coiled state, the material undergoes plastic deformation during heating, causing warping of the material. Therefore, the batch is not suitable for the deformation-relieving annealing of the present invention.

In the continuous annealing furnace, the furnace temperature is 300 to 700 占 폚, preferably 350 to 650 占 폚, the heating time is appropriately adjusted in the range of 5 seconds to 10 minutes, and the 0.2% Is adjusted to a value 10 to 50 MPa lower, preferably 15 to 45 MPa lower than the 0.2% proof stress (? ₀ ) before deformation removal annealing. As a result, the low elongation rate is increased and the bending workability is improved in the final cold rolling finish.

In the continuous annealing furnace, a tensile force is applied to the material in, for example, a direction parallel to the rolling direction, and the tension applied is 5 MPa or less, preferably 1 to 5 MPa, more preferably 2 to 4 MPa . If the tension is excessively large, it becomes difficult to adjust? / L to 150 or less. In addition, there is a tendency that an increase in elongation is not sufficient. On the other hand, if the tensile force is too small, the material passing through the annealing furnace may come into contact with the furnace wall, causing scratches on the surface or edge of the material.

One embodiment of the present invention provides a Cu-Zr-Ti alloy with a characteristic of? / L? 150 and a characteristic of I {220} / I ⁰ {220}? 4.0 to improve the drawing workability and bending workability And the manufacturing conditions for that are summarized and expressed,

(1) For? / L? 150,

a. In the deformation removing annealing, (σ ₀ - σ) = 10 to 50 MPa is adjusted.

b. The in-furnace tensile force in the deformation removing annealing is adjusted to 5 MPa or less.

(2) For I {220} / I ⁰ {220}? 4.0,

a. In the final cold rolling, the degree of processing per pass is adjusted to 15% or more.

b. The final cold-rolled total finish is 40 to 99%.

The copper alloy sheet produced in the above manner is processed into a new copper alloy product of various thicknesses (expanded copper product), and is used as a heat-dissipating electronic component in electric or electronic devices such as smart phones, tablet PCs, And the like.

Example

Embodiments of the invention will now be described, which are provided for a better understanding of the invention and its advantages and are not intended to be limiting.

The alloy element was added to molten copper and then cast into an ingot having a thickness of 200 mm. The ingot was heated at 950 占 폚 for 3 hours and hot rolled at 950 占 폚 to obtain a plate having a thickness of 15 mm. The oxide scale on the surface of the hot-rolled plate was grinded and removed by a grinder, and then annealing and cold rolling were repeated, and the final cold-rolled was finished to a predetermined product thickness. Finally, strain relief annealing was performed using a continuous annealing furnace.

Annealing (final recrystallization annealing) before the final cold rolling was carried out by using a batch furnace to change the crystal grain diameter and the conductivity after annealing by adjusting the furnace temperature in the range of 300 to 700 占 폚 with the heating time being 5 hours. In measuring the crystal grain diameter after annealing, the cross section perpendicular to the rolling direction was chemically corroded after the mirror polishing, and the average crystal grain diameter was determined according to the cutting method (JIS H 0501 (1999)).

In the final cold rolling, the total degree of processing and the degree of processing per pass were controlled. Further, the 0.2% proof stress of the material after the final cold rolling was obtained.

In the deformation removing annealing using the continuous annealing furnace, the furnace temperature was set to 500 ° C and the heating time was adjusted between 1 second and 15 minutes to change the 0.2% after annealing variously. Also, the tension added to the material in the furnace was varied in various ways. Also, deformation removal annealing is omitted for some materials.

The production conditions of the examples are shown in Tables 1 and 2 for each of the inventive and comparative examples. Here, a plurality of passes are performed in the final cold rolling, and these values represent the minimum values in the degree of machining of each of the passes. In Table 1, the notation "<5 μm" in the crystal grain diameter after the final recrystallization annealing indicates a case where only a part of the rolled structure is recrystallized.

The following measurements were made on the material during manufacture and the material after deformation-removal annealing.

(ingredient)

Alloying element concentration of the material after deformation removal annealing was analyzed by ICP-mass spectrometry.

(0.2% proof)

For the material after the final cold rolling and after the deformation removing annealing, the test piece No. 13B specified in JIS Z 2241 was taken in such a manner that the tensile direction was parallel to the rolling direction, and a tensile test was conducted in parallel with the rolling direction in accordance with JIS Z 2241 , And a 0.2% proof stress was obtained.

(Elongation)

Deformation Removal From the material after annealing, a No. 13B test piece specified in JIS Z 2241 was taken in such a manner that the tensile direction was parallel to the rolling direction, and the elongation was measured at a distance between the gaps of 50 mm.

(Conductivity)

From the material after deformation-removing annealing, a test piece was taken so that the longitudinal direction of the test piece was parallel to the rolling direction, and the conductivity at 20 캜 was measured by the four-terminal method according to JIS H 0505.

(Crystal orientation)

The X-ray diffraction integral intensity of the {220} plane in the thickness direction was measured with respect to the surface of the material after deformation-removing annealing. Similarly, the X-ray diffraction integral intensity of the {220} plane was measured for the pure copper powder standard sample. As the X-ray diffraction apparatus, RINT2500 manufactured by Rigaku Corporation was used, and measurements were made at Cu tube, tube voltage 25 kV, tube current 20 mA.

(Eric Sen)

The material after deformation removal annealing was tested under the conditions of sample shape Φ 90 mm, lubricant: grease, and punch pressing speed 5 mm / min using an Ericsen production tester to determine Erichen value. Table 2 shows the evaluation results.

(MBR / t)

(Goodway) direction in which the bending axis is in the direction perpendicular to the rolling direction and in the BW (Badway) direction in which the bending axis is in the same direction as the rolling direction according to JIS H 3130, and the W- , The ratio of the minimum bending radius (MBR) to the thickness (t) at which cracking did not occur (MBR / t) was obtained by changing the bending radius.

As can be seen from Tables 1 and 2, Inventive Examples 1 to 11 contain 0.01 to 0.50 mass% of one or both of Zr and Ti in total, and in the recrystallization annealing before final cold rolling, And the total working degree is adjusted to 40 to 99% in the final cold rolling. In the deformation removing annealing, the material is passed through a continuous annealing furnace at a tension of 1 to 5 MPa, and a 0.2% To 50 MPa. As a result, the copper alloy sheets of Inventive Examples 1 to 11 had a relationship of? / L? 150, and were able to achieve an electrical conductivity of 70% IACS or more, a 0.2% proof stress of 350 MPa or more, and a W bendability of MBR / t? 2.0 there was. In Inventive Examples 5 and 7, I {220} / I ⁰ {220} was less than 4.0 because the degree of processing per pass in the final cold rolling was less than 15%, and the Ericksen value / I0 {220} &gt; 4.0 and the Ericksen value / sheet thickness &gt; = ⁰ , while the degree of processing per pass was set to 15% or more in Examples 1 to 4, 6 and 8 to 11, 0.5. &Lt; / RTI &gt;

On the other hand, in Comparative Examples 1 and 2, deformation removal annealing was not performed, and sigma / L exceeded 200, resulting in poor bendability and drawability.

In Comparative Examples 3 to 6, the material tension in the furnace was more than 5 MPa, so that sigma / L was 150 or more, and in Comparative Example 5 where the tension was particularly high, sigma / L was more than 200 And the bending properties and drawing workability of Comparative Examples 3 to 6 were inferior.

In Comparative Examples 7 and 8, the degradation amount of the 0.2% proof stress in the deformation-removing annealing was too small, and (? ₀ -?) Deviated from the range of 10 to 50 MPa. Therefore, sigma / L exceeded 150, resulting in poor drawing processability and bending property.

In Comparative Example 9, the 0.2% proof stress after the deformation removing annealing was less than 350 MPa because the strength deterioration at the deformation removing annealing was large.

In Comparative Example 10, the total of one or both of Zr and Ti was less than 0.01% by mass, so that the 0.2% proof stress after deformation removal annealing was not less than 350 MPa.

In Comparative Example 11, since the total of one or both of Zr and Ti exceeded 0.5% by mass, the conductivity did not reach 70% IACS.

In Comparative Example 12, since the crystal grain diameter of the recrystallization annealing finish before the final cold rolling exceeded 50 占 퐉, in Comparative Example 13, the total processing degree in the final cold rolling was not less than 40%. Therefore, The proof stress was not less than 350 MPa.

From the above results, it is apparent that the present invention can provide a copper alloy plate having high strength and conductivity, excellent drawing workability and bending workability, and a large current electronic component and a heat dissipation electronic component having the same.

Claims (7)

Zr and Ti in an amount of 0.01 to 0.50 mass% in total, the balance of copper and inevitable impurities, a conductivity of 70% IACS or more, and a 0.2% proof stress of 350 MPa or more, Wherein a proof stress? (MPa) and an elongation percentage L (%) satisfy a relationship of? / L? 150. The method according to claim 1,
Zr and Ti in a total amount of 0.015 to 0.3 mass%. The method according to claim 1,
The X-ray diffraction integral intensity from the {220} plane of the pure copper powder standard sample was determined as I {220} by using the X-ray diffraction method and the X-ray diffraction integral intensity of the {220} when the intensity ^{I 0 {220}, I {} 220} / I 0 {220} ≥ 4.0 in the copper alloy plate. The method according to claim 1,
Wherein the minimum bending radius / plate thickness (MBR / t) in the rolling parallel direction (GW direction) and the direction perpendicular to the rolling direction (BW direction) in the W bending test is given by MBR / t? 2.0. The method according to claim 1,
0.0 &gt; Ericksen &lt; / RTI &gt; value / plate thickness of at least 0.5 in the Ericsen test. An electronic component for a large current including the copper alloy plate according to any one of claims 1 to 5. A heat dissipation electronic part comprising the copper alloy sheet according to any one of claims 1 to 5.