WO2017159749A1 - Copper alloy plate for heat-dissipation component - Google Patents

Abstract

The copper alloy plate for a heat dissipation component pertaining to the present invention includes 0.01-1.0 mass% Fe, 0.01-0.20 mass% P, 0.01-1.0 mass% Zn, and 0.01-0.15 mass% Sn, the remainder comprising Cu and unavoidable impurities. The copper alloy plate has a tensile strength of 410 MPa or greater, a yield strength of 390 MPa or greater, and an elongation of 5% or greater in the direction parallel to a rolling direction thereof, and has a tensile strength of 420 MPa or greater, a yield strength of 400 MPa or greater, and an elongation of 3% or greater in the direction perpendicular to the rolling direction thereof, the copper alloy plate has an electrical conductivity of 75% IACS or greater, the ratio R/t of the bend radius R and the plate thickness t thereof is set to 0.5, the bending limit width thereof is 70 mm or greater when the copper alloy plate is bent at 90 degrees at a bend line in the direction perpendicular to the rolling direction, and the bending limit width thereof is 20 mm or greater when the copper alloy plate is close-contact bent at a bend line in the direction perpendicular to the rolling direction.

Description

Copper alloy plate for heat dissipation parts

The present disclosure relates to a copper alloy plate material used for heat dissipation components that dissipate heat, such as CPUs and liquid crystals, mounted on electronic devices such as personal computers, tablet terminals, smartphones, mobile phones, and digital cameras.

Electronic devices such as personal computers, tablet terminals, smartphones, mobile phones, digital cameras, and digital video cameras use heat dissipation components that dissipate heat generated from electronic components such as CPUs, liquid crystals, and image sensors. Yes. The heat dissipating component is for preventing an excessive temperature rise of the electronic component and preventing a thermal runaway of the electronic component to function normally. As heat-dissipating parts, processed copper or other materials such as pure copper with high thermal conductivity, stainless steel with excellent strength and corrosion resistance, and white and light aluminum alloys are used. These heat dissipating parts have not only a heat dissipating function but also a role as a structural member for protecting the electronic parts mounted from external force applied to the electronic equipment.

Electronic components mounted on electronic devices are required to have high speed and high functionality, and the density of electronic components is constantly increasing. For this reason, the amount of heat generated by electronic components is rapidly increasing. In addition, heat sink parts are also required to be thin in response to demands for smaller, thinner, and lighter electronic devices. However, even when the heat dissipation component is thinned, it is required to maintain heat dissipation performance and structural strength.
A plate material, which is a material of the heat dissipation component, is formed into a heat dissipation component through plastic working such as hem bending (adhesion bending), 90 ° bending, and drawing. In bending, the width of the bent portion (the length of the bend line) is about several millimeters or less in the lead frame and the terminal, but in some heat dissipation parts, the width of the bent portion is about 20 mm or more. It is known that the bending workability of the plate material is abruptly lowered as the bending width is increased, and the heat dissipation component plate material is required to have strict bending workability as compared with the terminal and lead frame plate material.

Although pure copper is excellent in thermal conductivity as a material for the heat dissipation component, its strength is small and the heat dissipation component cannot be thinned. Stainless steel and Western white have low thermal conductivity (2 to 3% IACS) and cannot be applied as heat dissipation parts for electronic parts with large heat dissipation. Aluminum alloys have insufficient strength and thermal conductivity. On the other hand, as the copper alloy, Patent Documents 1 and 2 disclose Fe—P-based copper alloys for heat dissipation parts, but do not disclose bending workability in bending work with a wide bending part.

JP 2003-277853 A JP 2014-189816 A

An object of the embodiment of the present invention is to provide a copper alloy plate for a heat radiating component having high strength, excellent bending workability in bending work with a large bent portion width, and heat dissipation.

The copper alloy plate for a heat dissipation component according to the embodiment of the present invention includes Fe: 0.01 to 1.0 mass%, P: 0.01 to 0.20 mass%, Zn: 0.01 to 1.0 mass%, and Sn. : 0.01 to 0.15 mass%, the balance is Cu and inevitable impurities, the tensile strength in the rolling parallel direction is 410 MPa or more, the proof stress is 390 MPa or more, the elongation is 5% or more, the tensile strength in the direction perpendicular to the rolling Is 420 MPa or more, yield strength is 400 MPa or more, elongation is 3% or more, electrical conductivity is 75% IACS or more, the ratio R / t of the bending radius R to the sheet thickness t is 0.5, and the bending line is the direction perpendicular to the rolling direction. The bending limit width when performing 90-degree bending is 70 mm or more, and the bending limit width when performing close contact bending with the bending line being the direction perpendicular to the rolling is 20 mm or more.
The copper alloy further comprises one or more of Co, Al, Cr, Mg, Mn, Ca, Pb, Ni, Ti, Zr, Si, and Ag in a total of 0.3 mass% or less (Ni content is Less than 0.1 mass%).
If necessary, a surface coating layer can be formed on the surface of the copper alloy plate by plating or the like to improve the corrosion resistance. As the surface coating layer, a plating layer made of any one of Sn layer, Cu—Sn alloy layer, Ni, Co, Fe, Ni—Co alloy and Ni—Fe alloy can be considered.

According to the embodiment of the present invention, it has strength as a structural member, particularly strength that can withstand deformation and drop impact, bending workability that can withstand processing into a complex shape, and high heat dissipation against heat from semiconductor elements and the like. A copper alloy plate for a heat dissipation component can be provided. Moreover, when the said surface coating layer is formed in this copper alloy plate, corrosion resistance improves and it can prevent that the performance as a heat radiating member falls even in a severe environment.

It is a figure explaining the test method of the 90 degree | times bending test of an Example.

Hereinafter, the copper alloy plate for heat dissipation components according to the embodiment of the present invention will be described in detail.
<Composition of copper alloy plate>
The composition of the copper alloy is Fe: 0.01-1.0 mass%, P: 0.01-0.20 mass%, Zn: 0.01-1.0 mass%, and Sn: 0.01-0.15 mass%. The balance consists of Cu and inevitable impurities. This copper alloy contains 0.3 mass% in total of one or more of Co, Al, Cr, Mg, Mn, Ca, Pb, Ni, Ti, Zr, Si and Ag as subcomponents as necessary. The following may be included (excluding 0 mass%) (however, when Ni is included, the Ni content is less than 0.1 mass% (not including 0 mass%)).

Fe increases the strength of the copper alloy by precipitating an intermetallic compound with P described later. When the Fe content is less than 0.01 mass%, the precipitation amount of the Fe—P compound is small and the desired strength cannot be obtained. On the other hand, when the Fe content exceeds 1.0 mass%, the desired conductivity is obtained. Absent. Therefore, the Fe content is set to 0.01 to 1.0 mass%. The lower limit of the Fe content is preferably 0.03 mass%, more preferably 0.05 mass%, and the upper limit of the Fe content is preferably 0.8 mass%, more preferably 0.6 mass%.

P forms an intermetallic compound with Fe and precipitates in the parent phase of Cu to improve the strength. When the P content is less than 0.01 mass%, the Fe—P compound is not sufficiently precipitated, and the desired strength cannot be obtained. On the other hand, if the P content exceeds 0.20 mass%, the desired conductivity cannot be obtained. Therefore, the P content is set to 0.01 to 0.20 mass%. The lower limit of the P content is preferably 0.03 mass%, more preferably 0.05 mass%, and the upper limit of the P content is preferably 0.17 mass%, more preferably 0.15 mass%.

Zn has the function of improving the heat-resistant peelability of the solder and has the role of maintaining the solder joint reliability during assembly and after aging. However, if the Zn content is less than 0.01 mass%, it is insufficient for satisfying the heat-resistant peelability of the solder, and if it exceeds 1.0 mass%, the conductivity and thermal conductivity of the copper alloy are deteriorated. The lower limit of the Zn content is preferably 0.03 mass%, more preferably 0.05 mass%, and the upper limit of the Zn content is preferably 0.8 mass%, more preferably 0.6 mass%.

Sn contributes to improving the strength of the copper alloy, but if the Sn content is less than 0.01 mass%, sufficient strength cannot be obtained. Moreover, when content of Sn exceeds 0.15 mass%, the electrical conductivity and thermal conductivity of a copper alloy will be deteriorated. Therefore, the Sn content is set to 0.01 to 0.15 mass%. The lower limit of the Sn content is preferably 0.03 mass%, more preferably 0.05 mass%, and the upper limit of the Sn content is preferably 0.12 mass%, more preferably 0.10 mass%.

Further, Co, Al, Cr, Mg, Mn, Ca, Pb, Ni, Ti, Zr, Si, and Ag, which are added as subcomponents as necessary, improve the strength of the copper alloy and further increase the heat during production. It has the effect of improving the hot rolling property. However, when the total content of one or more of the subcomponents exceeds 0.3 mass%, the strength of the copper alloy is improved, but the electrical conductivity and thermal conductivity are lowered. Therefore, the total content of the subcomponents is set to 0.3 mass% or less (not including 0 mass%). However, when Ni is contained, the Ni content is less than 0.1 mass% (excluding 0 mass%).

<Characteristics of copper alloy sheet>
The heat dissipating component is required to have strength as a structural member, particularly strength that can withstand deformation and drop impact. If the tensile strength in the rolling parallel direction of the copper alloy plate is 410 MPa or more, the proof stress is 390 MPa or more, the tensile strength in the direction perpendicular to the rolling is 420 MPa or more, and the proof strength is 400 MPa or more, even if the heat dissipation member is thinned, the structural member The necessary strength can be secured. Further, if the elongation in the rolling parallel direction of the copper alloy plate is 5% or more and the elongation in the direction perpendicular to the rolling is 3% or more, the formability when the heat radiating member is formed from the copper alloy plate by bending or drawing. There is no particular problem. The proof stress is the tensile strength when 0.2% permanent elongation occurs in the tensile test.

When forming a heat dissipation member using a copper alloy plate as a material, the copper alloy plate generally requires excellent bending workability. When a copper alloy sheet is bent 90 degrees with a ratio R / t of the bending radius R to the sheet thickness t being 0.5 and the bending line being perpendicular to the rolling direction, the bending limit width is 70 mm or more, and the bending line is rolled. If the bending limit width when performing the close contact bending in the right angle direction is 20 mm or more, there is no problem in the manufacture of the heat dissipation component. When the bending limit width of the copper alloy plate does not reach the above value, cracks or breaks occur in the bent portion in the process of manufacturing the heat dissipation component, and it becomes difficult to form a complicated shape.

In order to absorb the heat generated from the semiconductor element and dissipate it to the outside, it is preferable that the conductivity of the copper alloy plate for the heat radiating component exceeds 75% IACS and the thermal conductivity exceeds 300 W / m · K. The thermal conductivity can be converted from the electrical conductivity according to the Wiedemann-Franz rule. If the electrical conductivity is 75% IACS or higher, the thermal conductivity is 300 W / m · K or higher.

<Method for producing copper alloy plate>
The copper alloy sheet according to the embodiment of the present invention can be manufactured by the steps of melt casting, homogenization treatment, hot rolling, cold rolling, recrystallization annealing, cold rolling, age annealing, and cold rolling. .
Appropriate conditions for melt casting and hot rolling are as follows, whereby precipitation of coarse Fe, Fe—P, Fe—PO, etc. can be prevented.
In the melt casting, Fe is added to a molten copper alloy at 1200 ° C. or higher to melt, and thereafter, the molten metal temperature is kept at 1200 ° C. or higher for casting. The ingot is cooled at a cooling rate of 1 ° C./second or more during solidification (when solid-liquid coexists) and after solidification. For that purpose, in the case of continuous casting or semi-continuous casting, it is necessary to sufficiently effect the primary cooling in the mold and the secondary cooling directly under the mold.

In the homogenization treatment, the ingot is heated to 900 to 1000 ° C. for 0.5 to 5 hours, and hot rolling is started at that temperature. The hot rolling end temperature is set to 650 ° C. or higher, desirably 700 ° C. or higher, and immediately after the hot rolling is finished, rapid cooling (preferably water cooling) is performed at a cooling rate of 20 ° C./second or higher.
The processing rate per pass of hot rolling affects not only hot-rolled materials but also the toughness of the final product, the homogeneity of the structure, and the densification. In order to manufacture the copper alloy plate for heat dissipation component according to the embodiment of the present invention, it is preferable that the average value of the processing rate per pass of hot rolling is 20% or more and the maximum processing rate is 25% or more. .
The reason is as described below.

When rolling by a rolling roll is applied, a compressive stress is applied in the rolling direction in a region having a constant depth hc from the surface of the rolling ingot, and a rolling direction is applied in the central region of the ingot thickness from the depth hc. It is known that compressive stress acts on the surface. In the region where the compressive stress acts, the compressive stress increases as the depth from the surface becomes shallower. In the region where the tensile stress acts, the tensile stress increases as the center of the ingot thickness is closer.
The depth hc changing from the compressive stress to the tensile stress can be obtained by calculation based on the rolling roll diameter, the reduction amount (thickness on the rolling roll entering side−thickness on the rolling roll exit side), etc. (OG Muzalevskii: Stal in English, June (1970), p.455). According to this calculation formula, when the rolling roll diameter is constant, hc increases as the rolling reduction increases. That is, the region where the tensile stress inside the ingot acts is reduced.

The ingot has defects such as a microcavity due to a shrinkage cavity or gas, microsegregation of alloy elements, and inclusions, and these defects increase as the center of the ingot thickness becomes closer. It is industrially difficult to make these defects zero.
When the ingot is heated for homogenization, microsegregation is eliminated by diffusion of alloy elements, but microcavities inside the ingot are not eliminated. Rather, by the homogenization treatment, Kirkendall voids are formed, and the gas components that have been dissolved in the ingot tend to precipitate at the inclusion-base metal interface or grain boundary, which tends to increase the microcavities inside the ingot. It is in.

Thus, since microcavities and inclusions are present inside the ingot, in order to increase the internal quality of the hot rolled material, it is preferable to increase the processing rate per pass of hot rolling. For this reason, it is preferable that the processing rate per pass of hot rolling is 20% or more on average and the maximum processing rate is 25% or more. More preferably, the average value of the processing rate per pass of hot rolling is 25% or more, and the maximum processing rate is 30% or more. In actual operation, it is preferable that the processing rate per pass of hot rolling is 35% or less on average and the maximum processing rate is 45% or less.

Also, by increasing the processing rate per pass of hot rolling, the number of hot rolling passes can be reduced, and hot rolling can be completed at a higher temperature. For this reason, rapid cooling (quenching) from a higher temperature is possible, and the amount of alloy elements in the hot rolled material can be increased. As a result, it is possible to improve the uniformity of the structure of the copper alloy sheet (product) after the subsequent cold rolling and heat treatment, and obtain good bending workability, drawing workability and stretch workability.

On the other hand, if a large reduction is applied to the ingot at the initial stage of hot rolling, cracks may occur on the rolled surface near the end face of the ingot. For this reason, in actual operation, rolling at a light working rate is generally performed from the first pass to the third pass of hot rolling.
However, if a rolling pass with a light working rate is continued at the initial stage of hot rolling, a tensile stress acts in the region from hc to the center of the ingot for each rolling pass, and the microcavity or inclusion-mother inside the ingot. The gap at the material interface expands and fine cracks occur. After that, even if the processing rate per pass is increased, the crimping of the crack once generated is delayed, and the internal quality of the hot rolled material is deteriorated. Copper alloy sheets produced by cold rolling and heat treatment of such hot-rolled materials are difficult to be subjected to severe processing such as wide bending, hem bending, drawing and overhanging with a small bending radius.

Therefore, in order to manufacture the copper alloy sheet according to the embodiment of the present invention, the average processing rate at the initial stage of hot rolling, specifically, the first to third passes is set to 10% or more and 35% or less. Is preferred. The average processing rate from the first pass to the third pass is more preferably 12% or more and 30% or less, and further preferably 15% or more and 25% or less.
Increasing the initial hot rolling ratio tends to cause hot rolling cracks in the ingot. To avoid this, it is preferable to roll the ingot end face with an edger before starting the first pass. By utilizing the edger, it is possible to increase the processing rate at the initial stage of rolling and to prevent or reduce the occurrence of internal cracks at the initial stage of rolling.
After hot rolling, both sides are chamfered and cold rolling is performed at an appropriate rolling rate.

In recrystallization annealing, heating is performed in a temperature range of 600 ° C. to 850 ° C. for 5 to 30 seconds in a continuous annealing furnace so that the average crystal grain size after recrystallization annealing is less than 20 μm. This recrystallization annealing is performed in order to improve the elongation and bending workability of the copper alloy sheet (product). When the recrystallization annealing temperature is less than 600 ° C. or the holding time is less than 5 seconds, the recrystallization becomes insufficient, and the bending workability of the copper alloy sheet (product) deteriorates. On the other hand, when the recrystallization annealing temperature exceeds 850 ° C. or the holding time exceeds 30 seconds, the recrystallized grains become coarse (the average crystal grain size becomes coarser to 20 μm or more), which is sufficient for a copper alloy sheet (product). Strength cannot be obtained. Furthermore, bending workability is inferior in wide bending.

After recrystallization annealing, cold rolling is performed as necessary. When this cold rolling is performed, the processing rate may be appropriately set within a range of 0 to 40% so that a predetermined processing rate and product sheet thickness can be obtained in finish cold rolling described later.
Subsequently, aging annealing is performed. The conditions for aging annealing are preferably 400 to 575 ° C. and 1 to 10 hours. When the temperature of the aging treatment is less than 400 ° C. or the holding time is less than 1 hour, precipitation is insufficient and the conductivity of the copper alloy sheet (product) is not improved. On the other hand, when the temperature of the aging treatment exceeds 575 ° C. or the holding time exceeds 10 hours, the precipitates become coarse, and sufficient strength cannot be obtained with the copper alloy plate (product).

After aging annealing, finish cold rolling is performed to the target thickness. The rolling rate is set to 30 to 85% according to the target product strength.
After finish cold rolling, annealing is performed for a short time if necessary. The conditions for this short time annealing are 250 to 450 ° C. and 3 to 40 seconds. By performing the annealing for a short time under these conditions, the distortion introduced in the finish cold rolling is removed. Further, under these conditions, there is no softening of the material and there is little decrease in strength.

<Surface coating layer of copper alloy plate>
By forming the surface coating layer on the copper alloy plate by plating or the like, the corrosion resistance of the heat dissipating component is improved, and the performance as the heat dissipating component can be prevented from being deteriorated even in a severe environment.
As the surface coating layer formed on the surface of the copper alloy plate, an Sn layer is preferable. If the thickness of the Sn layer is less than 0.2 μm, the corrosion resistance is not sufficiently improved, and if it exceeds 5 μm, the productivity is lowered and the cost is increased. Therefore, the thickness of the Sn layer is set to 0.2 to 5 μm. The Sn layer includes Sn metal and Sn alloy.

As the surface coating layer, a Cu—Sn alloy layer can be formed under the Sn layer. When the thickness of the Cu—Sn alloy layer exceeds 3 μm, the bending workability and the like deteriorate, so the thickness of the Cu—Sn alloy layer is set to 3 μm or less. The thickness of the Cu—Sn alloy layer is preferably 0.1 μm or more. In this case, the thickness of the Sn layer is 0 to 5 μm (including the case without the Sn layer), and the total thickness of the Cu—Sn alloy layer and the Sn layer is 0.2 μm or more. The upper limit of the total thickness is 8 μm.
In this specification, “the thickness of the Cu—Sn alloy layer” means the Sn equivalent thickness obtained by measuring the amount of Sn in the Cu—Sn alloy layer using a fluorescent X-ray film thickness meter. It is.

The Cu—Sn alloy layer may be exposed on the surface (see JP-A-2006-183068, JP-A-2013-185193, etc.). Since the Cu—Sn alloy layer is hard as Hv: 200 to 400, it has a scratch suppressing effect due to handling. The surface exposure rate of the Cu—Sn alloy layer (the value obtained by multiplying the surface area of the Cu—Sn alloy layer exposed per unit area of the material surface by 100) may be 100% or 0%. However, it is preferably 50% or less. Note that when there is no Sn layer on the Cu—Sn alloy layer (the thickness of the Sn layer is zero), the surface exposure rate of the Cu—Sn alloy layer is 100%. When the Cu—Sn alloy layer is not exposed, the surface exposure rate of the Cu—Sn alloy layer is 0%.

Under the Cu—Sn alloy layer, a plating layer made of any one of Ni, Co, Fe, Ni—Co alloy and Ni—Fe alloy can be further formed as an underlayer. When the thickness of the plating layer exceeds 3 μm, bending workability and the like are deteriorated, so the thickness is set to 3 μm or less. The thickness of this plating layer is preferably 0.1 μm or more.

Further, as the surface coating layer, only a plating layer made of any one of Ni, Co, Fe, Ni—Co alloy and Ni—Fe alloy (not including the Cu—Sn alloy layer and / or the Sn layer) is formed. be able to. The thickness of this plating layer is 3 μm or less from the viewpoint of preventing deterioration of bending workability and the like. The thickness of this plating layer is preferably 0.1 μm or more.
Each of the surface coating layers can be formed by electroplating, reflow plating, electroless plating, sputtering, or the like. The Cu-Sn alloy layer is formed by Sn plating on a copper alloy plate as a base material, or by performing Cu and Sn plating on a copper alloy base material and then performing a reflow process, etc., and reacting Cu and Sn. Can do. The heating conditions for the reflow process are 230 to 600 ° C. × 5 to 30 seconds.

No. in Table 1. The copper alloys having the compositions shown in 1 to 23 were melted in the air in a small electric furnace and melted into an ingot having a thickness of 50 mm, a length of 80 mm, and a width of 200 mm. Thereafter, the ingot was heated at 950 ° C. for 1 hour, then hot-rolled to a thickness of 12 mm, and immediately immersed in water and rapidly cooled. The hot rolling end temperature was 750 ° C. A hot rolling roll having a roll diameter of 450 mmφ was used. The hot rolling pass schedule is 5 pass finishing, 50 mm → 42 mm (16.0%) → 34 mm (19.0%) → 26 mm (23.5%) → 18 mm (30.8%) → 12 mm (33 .3%). The processing rate is shown in parentheses. The average value of the processing rate per pass is 24.5%. In addition, No. The copper contents of 1 to 23 had a hydrogen content of 0.5 to 1.0 mass ppm and an oxygen content of 4 to 18 mass ppm.

Next, both sides of the hot rolled material were each chamfered by about 1 mm to remove the oxide film, and cold rolled.
Subsequently, recrystallization annealing was performed at 720 ° C. for 20 seconds. The plate material after recrystallization annealing was water-cooled. The average crystal grain size (measured in the rolling parallel direction by the cutting method defined in JISH0501) measured on the plate surface after recrystallization annealing was less than 20 μm.
Next, after cold rolling with a processing rate of 35%, aging annealing was performed under conditions of 500 ° C. × 2 hours. Subsequently, the surface oxide was removed with a dilute sulfuric acid solution, and then finish cold rolling was performed at a processing rate of 50% to prepare a copper alloy strip having a thickness of 0.2 mm. After the finish cold rolling, annealing was performed at 350 ° C. for 30 seconds for a short time.

No. About the copper alloy (No. 24) of the same composition as No. 1, hot rolling was implemented by a different pass schedule.
No. The 24 pass schedule is a 10 pass finish, 50 mm → 46 mm (8.0%) → 41 mm (10.9%) → 36 mm (12.2%) → 31 mm (13.9%) → 26 mm (16.1) %) → 22 mm (15.4%) → 19 mm (13.6%) → 16 mm (15.8%) → 14 mm (12.5%) → 12 mm (14.3%). The parentheses indicate the processing rate, and the average value of the processing rate per pass is 13.3%. After 5 passes, the temperature was raised again by inserting it into a furnace at 950 ° C., and after 10 passes, it was immersed in water and rapidly cooled. The temperature of the hot rolled material immediately after the end of 10 passes was 810 ° C. No. 24, the conditions of the processes other than hot rolling are No. 24. Same as 1-23. In addition, No. 24, the average crystal grain size measured on the plate surface after recrystallization annealing was less than 20 μm (the measurement method is the same as the method described above).

Using the copper alloy strip (product plate) obtained in the above process as a test material, mechanical properties, electrical conductivity, bending limit width, and solderability were measured and evaluated in the following manner. Further, the thermal conductivity was calculated from the electrical conductivity according to the Wiedemann-Franz rule.
These results are shown in Table 2.

<Mechanical properties>
From each specimen, JIS No. 5 test specimens were collected so that the longitudinal direction was parallel and perpendicular to the rolling direction, and a tensile test was conducted based on the provisions of JISZ2241, and the parallel direction (∥) and vertical direction ( The tensile strength, yield strength and elongation of ii) were measured.
<Conductivity>
The conductivity was measured based on the provisions of JISH0505. The electrical resistance was measured by a four-terminal method using a double bridge.

<Bending limit width of 90-degree bending>
Square specimens with different widths of 30 mm in length and 10 to 100 mm in width (widths of 10, 15, 20, 25 ... and up to 100 mm in width every 5 mm) from the test material (three for each width) Was made. The direction of the 30 mm long side of the test piece was made parallel to the rolling direction of the specimen. Using this test piece, the V-shaped block 1 and the metal fitting 2 shown in FIG. 1 are set in a hydraulic press, the ratio R / t of the bending radius R to the plate thickness t is set to 0.5, and the bending line (the paper surface of FIG. The direction perpendicular to the width direction of the test piece 3 was set as the width direction of the test piece 3 (Good Way bending), and bending was performed 90 degrees. The width of the V-shaped block 1 and the metal fitting 2 (thickness in the direction perpendicular to the paper surface of FIG. 1) was 120 mm. The load of the hydraulic press was 1000 kgf (9800 N) per 10 mm width of the test piece.
After the bending test, the entire outer length of the bent portion of the test piece was observed with a 100 × optical microscope, and when no crack was observed in any of the three test pieces, it was determined to be acceptable, and the others were determined to be unacceptable. . The maximum width of the test specimen that passed was taken as the bending limit width of the specimen.

<Bending limit width of contact bending>
In the same manner as the 90-degree bending test, a rectangular shape with a width of 30 mm and a width of 5 to 50 mm (width 5, 10, 15, 20,. Test pieces (three for each width) were prepared. The direction of the 30 mm long side of the test piece was made parallel to the rolling direction. Using this test piece, the ratio R / t of the bending radius R to the plate thickness t is 2.0, the direction of the bending line is the width direction of the test piece (Good Way), and approximately 170 degrees according to the JISZ2248 specification. After bending to close, bending was performed.
After the bending test, the presence or absence of cracks in the bent part was observed with a 100-fold optical microscope, and the case where no crack was observed in any of the three test pieces was determined to be acceptable, and the others were determined to be unacceptable. The maximum width of the test specimen that passed was taken as the bending limit width of the specimen.

<Solderability evaluation>
Using a Sn-3Ag-0.5Cu solder, a solder wetting test by the meniscograph method was performed. An active flux is dip-coated on a test piece processed to a size of 10 mm × 30 mm, and then immersed in a solder bath having a bath temperature of 265 ° C. (immersion rate: 25 mm / sec, immersion depth: 12 mm, immersion time: 5 0.0 sec), and zero cross time (solder wetting time) was measured. A solder wetting time of less than 1.5 seconds was evaluated as pass (◯), and 1.5 seconds or more was evaluated as reject (x).

As shown in Tables 1 and 2, the alloy composition defined in the embodiment of the present invention has a hot rolling pass schedule within a preferable range (average value of processing rate per pass is 20% or more, maximum No. with a processing rate of 25% or more). In Nos. 1 to 14, the tensile limit, proof stress, elongation, electrical conductivity, bending limit width of 90-degree bending and contact bending satisfy the provisions of the embodiment of the present invention.
On the other hand, No. having no alloy composition defined in the embodiment of the present invention. 15 to 23 and No. in which the hot rolling pass schedule is out of the preferred range. 24, any one or more of tensile strength, yield strength, elongation, conductivity, bending limit width of 90-degree bending and contact bending, and solderability do not satisfy the definition of the embodiment of the present invention.

No. No. 15 has an excessive Fe content and low electrical conductivity and thermal conductivity.
No. No. 16 has insufficient Fe content, low tensile strength and yield strength, and low electrical conductivity and thermal conductivity.
No. No. 17 has an excessive P content and low electrical conductivity and thermal conductivity.
No. No. 18 has insufficient P content, and has low tensile strength and yield strength.
No. No. 19 has an excessive Zn content and low electrical conductivity and thermal conductivity.
No. No. 20 lacks Zn content and is inferior in solderability.
No. No. 21 has an excessive Sn content, low electrical conductivity and low thermal conductivity, and inferior bending limit width for 90-degree bending and contact bending.
No. No. 22 has a short Sn content and a low tensile strength and yield strength.
No. In No. 23, the total content of subcomponents is excessive, and the electrical conductivity and thermal conductivity are low.
No. No. 24 has a small bending limit width for 90-degree bending and contact bending because the hot rolling pass schedule is out of the preferred range.

The copper alloys having the compositions (2 types) shown in Table 3 were melted and melted into an ingot having a thickness of 200 mm, a width of 500 mm, and a length of 5000 mm. Thereafter, the ingot was heated at 950 ° C. for 1 hour, then hot-rolled to a thickness of 12 mm, and immediately immersed in water and rapidly cooled. The hot rolling end temperature was 750 ° C. In addition, a plate | board thickness becomes thin for every pass of hot rolling, and the temperature fall of a hot rolling material becomes large. The length of the hot rolled material at the end of hot rolling is over 80 m, and the hot rolling end temperature is different at both ends, but the hot rolling end temperature is a temperature measured at the lower end of the hot rolling end temperature. is there. In this example, the difference in hot rolling end temperature at both ends was about 20 ° C. The hot rolling pass schedule is 9 pass finishing, 200 mm → 177 mm (11.5%) → 156 mm (11.9%) → 123 mm (21.2%) → 98 mm (20.3%) → 72 mm (26 0.5%) → 46 mm (36.1%) → 27 mm (41.3%) → 18 mm (33.3%) → 12 mm (33.3%). The processing rate is shown in parentheses. The average value of the processing rate per pass is 26.2%.
Next, both sides of the hot rolled material were each chamfered by about 1 mm to remove the oxide film, and cold rolled.

Each of the two types of cold-rolled material is divided into three (Nos. 25 to 27, 28 to 30). Nos. 25 and 28 were subjected to recrystallization annealing and water cooling at 720 ° C. for 20 seconds. Nos. 26 and 29 were not subjected to recrystallization annealing. Nos. 27 and 30 were subjected to recrystallization annealing and water cooling at 920 ° C. for 30 seconds. At this stage, no. The average crystal grain size (measured in the rolling parallel direction by the cutting method defined in JISH0501) of 25 to 30 plate surfaces was measured. No. 1 was recrystallized under proper conditions. No. 25 and No. 27 have an average grain size of 10 μm, and No. no recrystallization annealing. Since Nos. 26 and 29 remained in the fiber structure, the average crystal grain size could not be measured. In addition, the recrystallization annealing temperature was too high. The average grain size of 27 and 30 was 30 μm, which was larger than the appropriate level (less than 20 μm).
Subsequently, no. The plate materials 25 to 30 were subjected to cold rolling, aging annealing, pickling, finish cold rolling and short-time annealing in the same steps and conditions as in [Example 1].

No. Using 25 to 30 copper alloy strips (product plates) as test materials, mechanical properties, electrical conductivity, bending limit width, and solderability were measured and evaluated in the same manner as in Example 1. Further, the thermal conductivity was calculated from the electrical conductivity according to the Wiedemann-Franz rule. These results are shown in Table 4.

No. 25 to 30 both have the alloy composition defined in the embodiment of the present invention. As shown in Table 4, No. 1 was subjected to recrystallization annealing under appropriate conditions. Nos. 25 and 28 satisfy the requirements of the embodiment of the present invention in terms of the bending limit width of tensile strength, proof stress, elongation, electrical conductivity, 90-degree bending, and contact bending. On the other hand, no. Nos. 25 and 28, and the conditions for recrystallization annealing were inappropriate. In Nos. 26 and 29, the bending limit width of 90-degree bending and contact bending does not satisfy the definition of the embodiment of the present invention.

Next, no. No. 7 copper alloy strip (product plate) was used as a test material, and one or more of Ni plating, Cu plating, Sn plating, and Ni—Co alloy plating were applied to each surface at a predetermined thickness. All are electroplating, Table 5 shows the plating bath composition and plating conditions of each plating, and Table 6 shows the thickness of each plating layer.
No. in Table 6 31 to 33, 36, 37 and 39 to 42 are obtained by performing Cu plating and Sn plating after performing (or without) Ni plating or Ni—Co plating, and then performing reflow treatment. The layer thickness is that after reflow treatment. The reflow treatment was performed at 450 ° C. for 15 seconds, and the cooling following the reflow treatment was water cooling. This is a normal reflow processing condition. No. The Cu—Sn layers 31 to 33, 36, 37, and 39 to 42 are formed by reaction of Cu of Cu plating and Sn of Sn plating by a reflow process. Cu plating disappeared by reflow treatment.
No. in Table 6 No. 38 was obtained by performing Ni plating, Cu plating, and Sn plating. As time passed, Cu of Cu plating and Sn of Sn plating reacted to form a Cu—Sn alloy layer, and the Cu plating disappeared. The thickness of the Sn plating layer is that after Cu plating disappears.

The thickness of each plating layer was measured by the following method.
<Sn layer>
First, the total thickness of Sn layer (total thickness of Sn layer including Cu—Sn alloy layer) is measured using a fluorescent X-ray film thickness meter (Seiko Electronics Co., Ltd .; model SFT3200). Thereafter, the substrate is immersed in a stripping solution containing p-nitrophenol and caustic soda as main components for 10 minutes, and after the Sn layer is stripped, the amount of Sn in the Cu—Sn alloy layer is measured using a fluorescent X-ray film thickness meter. The Sn layer thickness was calculated by subtracting the Sn amount in the Cu—Sn alloy layer from the Sn layer total thickness thus determined.

<Cu-Sn alloy layer>
After dipping in a stripping solution containing p-nitrophenol and caustic soda as main components for 10 minutes and stripping the Sn layer, the amount of Sn in the Cu—Sn alloy layer is measured using a fluorescent X-ray film thickness meter. The thickness of the Cu—Sn alloy layer is the Sn equivalent thickness.
<Ni layer and Ni-Co layer>
The thicknesses of the Ni layer and the Ni—Co alloy layer were measured using a fluorescent X-ray film thickness meter.

<Cu-Sn alloy layer exposure rate>
The surface of each test material after plating (with a Cu-Sn alloy layer formed) was observed with a SEM (scanning electron microscope), and surface composition images (× 200) obtained for any three fields of view were obtained. Binarization processing was performed. Thereafter, the average value of the material surface exposure rate of the Cu—Sn alloy coating layer in the three visual fields was measured by image analysis.

No. Test pieces were prepared from the respective test materials 31 to 43, and the corrosion resistance and bending workability were measured as follows.
<Corrosion resistance>
The corrosion resistance of the test material after plating was evaluated by a salt spray test. Using 99.0% deionized water (manufactured by Wako Pure Chemical Industries, Ltd.) containing 5% by mass of NaCl, the test conditions were: test temperature: 35 ° C. ± 1 ° C., spray solution PH: 6.5 to 7.2 Spray pressure: 0.098 ± 0.01 MPa, sprayed for 72 hours, washed and dried. Subsequently, the surface of the test piece was observed with a stereomicroscope, and the presence or absence of corrosion (base metal corrosion and spot corrosion on the plating surface) was observed.

<Bending workability evaluation of plating material>
From each test material after plating, a rectangular test piece having a length of 30 mm and a width of 20 mm (three for each test material) was prepared. The direction of the 30 mm long side of the test piece was made parallel to the rolling direction of the specimen (base material). Using this test piece, the V-shaped block 1 and the metal fitting 2 shown in FIG. 1 are set in a hydraulic press, the ratio R / t of the bending radius R and the plate thickness t is 2.0, and the direction of the bending line is the base material. The film was bent 90 degrees in the direction perpendicular to the rolling direction. The load of the hydraulic press was 1000 kgf (9800 N) per 10 mm width of the test piece.
After the bending test, the entire outer length of the bent portion of the test piece was observed with a 100 × optical microscope. No crack was observed in any of the three test pieces, and no crack was observed even in one place. The case was determined to be cracked.

As shown in Table 6, No. having the plating configuration and each plating layer thickness defined in the embodiment of the present invention. In Nos. 31 to 40, no base metal corrosion was observed in the salt spray test, and no cracks occurred in the bending workability test. It should be noted that No. 2 in which an underlayer composed of a Ni layer or a Ni—Co alloy layer is not formed. No. 33 and No. 33 in which no Sn layer remained and the Cu—Sn alloy layer was exposed on the surface. In No. 37, no base metal corrosion was observed, but spot corrosion (a phenomenon in which the surface of the coating layer corrodes in the form of dots) was observed.

On the other hand, the plating layer thickness is different from that of the embodiment of the present invention. In Nos. 41 to 43, base metal corrosion was observed in the salt spray test, or cracking occurred in the plating in the bending workability test.
No. In No. 41, the total thickness of the Cu—Sn alloy layer and the Sn layer was insufficient, and the base metal corrosion occurred.
No. In Nos. 42 and 43, the Cu—Sn alloy layer or the Ni layer was thick, and cracking occurred in the plating in the bending test.

The present invention includes the following aspects.
Aspect 1:
Fe: 0.01 to 1.0 mass%, P: 0.01 to 0.20 mass%, Zn: 0.01 to 1.0 mass%, and Sn: 0.01 to 0.15 mass%, with the balance being Cu And inevitable impurities,
Tensile strength in the rolling parallel direction is 410 MPa or more, proof stress is 390 MPa or more, elongation is 5% or more,
The tensile strength in the direction perpendicular to rolling is 420 MPa or more, the proof stress is 400 MPa or more, and the elongation is 3% or more,
Conductivity is 75% IACS or higher,
The bending limit width when bending 90 degrees with the ratio R / t of the bending radius R and the sheet thickness t being 0.5 and the bending line being perpendicular to the rolling direction is 70 mm or more,
A copper alloy plate for a heat-radiating component, characterized in that a bending limit width is 20 mm or more when close bending is performed with a bending line as a direction perpendicular to rolling.
Aspect 2:
Furthermore, it is described in the aspect 1 characterized by including one or more of Co, Al, Cr, Mg, Mn, Ca, Pb, Ti, Zr, Si, and Ag in a total of 0.3 mass% or less. Copper alloy plate for heat dissipation parts.
Aspect 3:
Furthermore, it contains one or more of Co, Al, Cr, Mg, Mn, Ca, Pb, Ti, Zr, Si, and Ag, and less than 0.1 mass% of Ni in total of 0.3 mass% or less. The copper alloy plate for heat radiating components described in the aspect 1.
Aspect 4:
4. The copper alloy plate for heat dissipation component according to any one of aspects 1 to 3, wherein an Sn layer having a thickness of 0.2 to 5 μm is formed on the surface.
Aspect 5:
A Cu—Sn alloy layer having a thickness of 3 μm or less and a Sn layer having a thickness of 0 to 5 μm are formed in this order on the surface, and the total thickness of the Cu—Sn alloy layer and the Sn layer is 0.2 μm or more. A copper alloy plate for a heat-radiating component according to any one of aspects 1 to 3.
Aspect 6:
A plating layer made of any one of Ni, Co, Fe, Ni—Co alloy and Ni—Fe alloy having a thickness of 3 μm or less on the surface, a Cu—Sn alloy layer having a thickness of 3 μm or less, and a thickness of 0 to 5 μm 4. The copper alloy plate for a heat dissipation component according to any one of aspects 1 to 3, wherein the Sn layer is formed in this order, and the total thickness of the Cu—Sn alloy layer and the Sn layer is 0.2 μm or more.
Aspect 7:
Any one of aspects 1 to 3, wherein a plating layer made of any one of Ni, Co, Fe, Ni—Co alloy and Ni—Fe alloy having a thickness of 3 μm or less is formed on the surface. Copper alloy plate for heat dissipation parts.
Aspect 8:
The copper alloy plate for a heat dissipation component according to aspect 5 or 6, wherein the Cu—Sn alloy layer is exposed on the outermost surface, and the exposed area ratio is 50% or less.
Aspect 9:
A heat dissipating component comprising the copper alloy plate for heat dissipating component according to any one of aspects 1 to 8.
Aspect 10:
A coil comprising a copper alloy plate for a heat dissipation component according to any one of aspects 1 to 8.

This application is accompanied by a priority claim based on Japanese Patent Application No. 2016-054204, whose application date is March 17, 2016. Japanese Patent Application No. 2016-054204 is incorporated herein by reference.

1 V-shaped block 2 Press fitting 3 Test piece

Claims (20)

1. Fe: 0.01 to 1.0 mass%, P: 0.01 to 0.20 mass%, Zn: 0.01 to 1.0 mass%, and Sn: 0.01 to 0.15 mass%, with the balance being Cu And inevitable impurities,
   Tensile strength in the rolling parallel direction is 410 MPa or more, proof stress is 390 MPa or more, elongation is 5% or more,
   The tensile strength in the direction perpendicular to rolling is 420 MPa or more, the proof stress is 400 MPa or more, and the elongation is 3% or more,
   Conductivity is 75% IACS or higher,
   The bending limit width when bending 90 degrees with the ratio R / t of the bending radius R and the sheet thickness t being 0.5 and the bending line being perpendicular to the rolling direction is 70 mm or more,
   A copper alloy plate for a heat-radiating component, characterized in that a bending limit width is 20 mm or more when close bending is performed with a bending line as a direction perpendicular to rolling.
2. Furthermore, the total content of one or more of Co, Al, Cr, Mg, Mn, Ca, Pb, Ti, Zr, Si, and Ag is 0.3 mass% or less. Copper alloy plate for heat dissipation parts.
3. Furthermore, it contains one or more of Co, Al, Cr, Mg, Mn, Ca, Pb, Ti, Zr, Si, and Ag, and less than 0.1 mass% of Ni in total of 0.3 mass% or less. The copper alloy plate for heat radiating components according to claim 1.
4. 4. The copper alloy plate for a heat-radiating component according to claim 1, wherein a Sn layer having a thickness of 0.2 to 5 μm is formed on the surface.
5. A Cu—Sn alloy layer having a thickness of 3 μm or less and a Sn layer having a thickness of 0 to 5 μm are formed in this order on the surface, and the total thickness of the Cu—Sn alloy layer and the Sn layer is 0.2 μm or more. The copper alloy plate for a heat radiation component according to any one of claims 1 to 3.
6. A plating layer made of any one of Ni, Co, Fe, Ni—Co alloy and Ni—Fe alloy having a thickness of 3 μm or less on the surface, a Cu—Sn alloy layer having a thickness of 3 μm or less, and a thickness of 0 to 5 μm 4. The copper alloy plate for a heat dissipation component according to claim 1, wherein the Sn layer is formed in this order, and the total thickness of the Cu—Sn alloy layer and the Sn layer is 0.2 μm or more. .
7. 4. The plating layer of any one of Ni, Co, Fe, Ni—Co alloy and Ni—Fe alloy having a thickness of 3 μm or less is formed on the surface. The described copper alloy plate for heat dissipation parts.
8. 6. The copper alloy plate for a heat radiating component according to claim 5, wherein the Cu—Sn alloy layer is exposed on the outermost surface, and the exposed area ratio is 50% or less.
9. The copper alloy plate for a heat-radiating component according to claim 6, wherein the Cu-Sn alloy layer is exposed on the outermost surface and the exposed area ratio is 50% or less.
10. A heat dissipating part comprising the copper alloy plate for a heat dissipating part according to any one of claims 1 to 3.
11. A heat dissipating component comprising the copper alloy plate for heat dissipating component according to claim 4.
12. A heat dissipating component comprising the copper alloy plate for heat dissipating component according to claim 5.
13. A heat dissipating component comprising the copper alloy plate for heat dissipating component according to claim 6.
14. A heat dissipating component comprising the copper alloy plate for heat dissipating component according to claim 7.
15. A heat dissipating component comprising the copper alloy plate for heat dissipating component according to claim 8.
16. A heat dissipating component comprising the copper alloy plate for heat dissipating component according to claim 9.
17. A coil comprising a copper alloy plate for a heat dissipation component according to any one of claims 1 to 3.
18. A coil made of a copper alloy plate for a heat dissipation component according to claim 4.
19. A coil made of a copper alloy plate for a heat dissipation component according to claim 5.
20. A coil made of a copper alloy plate for a heat dissipation component according to claim 6.

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