JPH09209061A - Copper alloy with excellent plating adhesion - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a copper alloy having excellent plating adhesion. SOLUTION: Ni: 0.5 to 3% by weight, Si: 0.0
8 to 0.7% by weight, Sn: 0.1 to 0.9% by weight, Z
n: 0.1 to 3% by weight, Fe: 0.007 to 0.25% by weight, P: 0.001 to 0.2% by weight, Mg: 0.00
1 to 0.2% by weight, Pb: 0.001 to 0.01% by weight
And further contains Li, In, Ba, Pd, Au, P
One or two or more of t, Rh, and Ir are contained in a total amount of 0.0002 to 0.05% by weight, and if necessary, one or two of Cr and Zr are 0 in total. 0.01 to 0.3% by weight with the balance being Cu and inevitable impurities.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention not only excels in tensile strength, elongation, conductivity and thermal creep properties, but also
The present invention relates to a copper alloy having excellent plating adhesion, particularly Ni plating adhesion. This copper alloy is used for various terminals, relays,
Breaker, volume, contact spring, switch, fuse, lamp socket, IC socket, lead frame,
It can be used for manufacturing not only electric and electronic parts such as connectors but also other spring parts. Among these applications, the copper alloy of the present invention is most suitable for manufacturing electric and electronic parts, particularly connectors.

[0002]

2. Description of the Related Art Generally, electric and electronic parts are manufactured by forming a copper alloy into a thin plate and subjecting the thin plate to metal working such as press working, punching working, and bending working. In this case, plating is often performed at the stage of the copper alloy thin plate, or finally after being processed.

The copper alloy used at this time is Ni:
0.5-3% by weight, Si: 0.02-0.7% by weight, Z
n: 0.1 to 3% by weight, Sn: 0.1 to 0.9% by weight,
Mg: 0.001-0.2 wt%, Ca: 0.001-
A copper alloy containing 0.01% by weight, Pb: 0.001 to 0.01% by weight, and the balance of Cu and inevitable impurities (see Japanese Patent Publication No. 5-24217), N.
i: 0.5-3 wt%, Si: 0.08-0.8 wt%, Zn: 0.1-3 wt%, Sn: 0.1-0.9 wt%, Fe: 0.007- 0.25% by weight, P: 0.0
A copper alloy having a composition of 01 to 0.2% by weight and the balance of Cu and unavoidable impurities (JP-A-3-566).
No. 36), Ni: 1.0 to 3.5% by weight, S
i: 0.2-0.9 wt%, Mn: 0.01-1.0 wt%, Zn: 0.1-5 wt%, Sn: 0.1-2.0
%, Mg: 0.001-0.01% by weight,
Further, one or more of Cr, Ti, and Zr:
A copper alloy having a composition containing 0.001 to 0.01% by weight and the balance of Cu and unavoidable impurities (Japanese Patent Laid-Open Publication No. Sho 6-96 (1994)).
1-127842), etc., and these copper alloys are excellent in tensile strength, elongation, electrical conductivity, and thermal creep characteristics, and various electric and electronic parts are manufactured using thin plates of these copper alloys. It is also known to do.

The electric and electronic parts manufactured from these conventional copper alloy thin plates, for example, connectors, are Sn-plated on the surface thereof, but the connectors directly plated with Sn are used around automobile engines. When used for a long time in an environment with high temperature and vibration, Cu of the material diffuses into the Sn plating layer and the contact resistance becomes unstable. Therefore, first, Ni
It is considered that a method of forming an undercoat and forming Sn plating on the Ni undercoat to prevent Cu of the material from diffusing into the Sn plating layer is effective.

[0005]

However, copper alloys are usually subjected to solution treatment to finely precipitate intermetallic compounds of Ni and Si in the matrix to improve the thermal creep properties and to improve the heat resistance. Although a treatment for improving is performed, when a solution treatment is applied to a conventional copper alloy, Si is concentrated at grain boundaries and interfaces to form a Si oxide film, and the Si oxide film formed by the solution treatment is Hinders the adhesion of the plating,
If the Sn-plated connector with Ni undercoat is used for a long time in an environment with high temperature and vibration, the Ni undercoat will peel off and S
There is a problem that the adhesion of n-plating is also reduced.

[0006]

Means for Solving the Problems Accordingly, the present inventors have:
From this point of view, as a result of research to obtain a copper alloy having excellent plating adhesion, in which the Ni undercoat does not peel off even when used in an environment with high temperature and vibration such as around an engine of an automobile, : 0.5 to 3% by weight, Si: 0.
08-0.7 wt%, Sn: 0.1-0.9 wt%, Z
n: 0.1 to 3% by weight, Fe: 0.007 to 0.25% by weight, P: 0.001 to 0.2% by weight, Mg: 0.00
1 to 0.2% by weight, Pb: 0.001 to 0.01% by weight, 0.002 in total of one or more of Li, In, Ba, Pd, Au, Pt, Rh and Ir. ~
0.05% by weight, and if necessary, one or two of Cr and Zr in total of 0.01 to
A copper alloy containing 0.3% by weight and the balance consisting of Cu and unavoidable impurities has excellent plating adhesion even when Ni undercoating is performed after solution treatment, and it is likely to be used around automobile engines. The inventors have obtained the knowledge that the Ni undercoat does not peel off even when used in an environment with high temperature and vibration.

The present invention has been made on the basis of such knowledge, and Ni: 0.5 to 3% by weight, Si:
0.08-0.7% by weight, Sn: 0.1-0.9% by weight, Zn: 0.1-3% by weight, Fe: 0.007-0.
25% by weight, P: 0.001-0.2% by weight, Mg:
0.001-0.2% by weight, Pb: 0.001-0.0
1% by weight, Li, In, Ba, Pd, Au, Pt, Rh
And one or more of Ir in total 0.00
02-0.05% by weight, and if necessary C
One or two of r and Zr is 0.01 in total.
It is characterized by a copper alloy containing 0.3 to 0.3% by weight and the balance of Cu and unavoidable impurities and having excellent plating adhesion.

Next, the reason why the composition of the copper alloy of the present invention having excellent plating adhesion is limited as described above will be explained.

(A) Ni and Si These components form an intermetallic compound of Ni and Si in the coexisting state to improve the strength and spring property without significantly lowering the conductivity, and increase the softening temperature. , Has the effect of improving creep resistance at high temperatures, but the effect is not sufficient if the Ni content is less than 0.5 wt% and the Si content is less than 0.08 wt%, while the Ni content is Is more than 3% by weight and the Si content is more than 0.7% by weight, it is not preferable because it deteriorates hot workability and conductivity and adversely affects plating adhesion.
Therefore, Ni: 0.5 to 3% by weight, Si: 0.08
˜0.7 wt%. A more preferable range is Ni:
1.7 to 2.7% by weight, Si: 0.2 to 0.7% by weight.

(B) Sn Sn has the effect of further improving the spring property and bending workability, but if its content is less than 0.1%, the desired spring property cannot be ensured. Content 0.9
%, The migration resistance and conductivity tend to decrease, so the Sn content is less than 0.1%.
It was set to 1 to 0.9%. A more preferable range of Sn content is 0.2 to 0.79%.

(C) Zn Zn has an action of further improving the solder heat resistance peeling resistance and the migration resistance, but its content is 0.1.
If it is less than 1%, the desired effect cannot be obtained, while if it exceeds 3%, the solderability is impaired. Therefore, the content is set to 0.1 to 3%. A more preferable range of Zn content is 0.4 to 2.0%.

(D) Fe Fe improves the hot rolling property (suppresses the generation of surface cracks and edge cracks) and makes the intermetallic compound of Ni and Si finer to improve the plating heating adhesion. Although there is an effect, if the content is less than 0.007%, the desired effect cannot be obtained, while if the content exceeds 0.25%, the hot rolling effect tends to decrease. ,
The Fe content was set to 0.007 to 0.25%. A more preferable range of the Fe content is 0.01 to 0.12%.

(E) Mg The Mg component has a function of improving hot rolling property and Pb.
In the state of coexisting with, it has an effect of improving the abrasion resistance of the punching die, but if its content is less than 0.001%, the desired effect cannot be obtained, while if its content exceeds 0.2%. However, since it becomes easy to form a large Mg sulfide and defects occur in bending processing of the plated material, the content thereof is set to 0.001 to 0.2%. A more preferable range of the Mg content is 0.001 to 0.1%.

(F) Pb Pb is effective in reducing the wear of the punching die by concentrating in the crystal grain boundaries of the copper alloy matrix and especially coexisting with Mg, but its content is 0.001%. If it is less than 0.01%, the effect is not sufficient, while if it exceeds 0.01%, the hot-rolled product is deteriorated.
The Pb content was set to 0.001 to 0.01%. A more preferable range is 0.002 to 0.007%.

(G) For P P, the decrease in spring property caused by bending is suppressed,
Therefore, there is an effect of improving the insertion / removal characteristics and an effect of improving the migration resistance of the connector obtained by molding, but if the content is less than 0.001%, the effect is not sufficient, while 0.2 %, The solder heat peeling resistance is significantly impaired, so the P content is set to 0.001 to 0.2%. A more preferable range is 0.003 to 0.04%.

(H) Cr and Zr Cr and Zr, in addition to the intermetallic compound of Ni and Si, form fine precipitates to enhance heat resistance and further improve creep resistance at high temperature. However, if the total amount of one or two of Cr and Zr is less than 0.01%, the effect is not sufficient, while if it exceeds 0.3%, the effect is insufficient. Since large precipitates containing Cr or Zr will develop and the adhesion of the plating will be impaired, its content was set to 0.01 to 0.3%. A more preferable range is 0.012 to 0.150%.

(I) Li, In, Ba, Pd, Au,
Pt, Rh, Ir These components prevent the intermetallic compound of Ni and Si from coarsely growing in the base material by the solution treatment, condensing at the crystal grain boundaries, or forming a Si oxide film to prevent the adhesion of plating. Has the effect of preventing the damage of the Ni undercoat and improving the reliability of the Ni undercoat, but the sum of the above elements is 0.0002%.
Less than is not enough to improve plating reliability,
On the other hand, if the total amount of these components exceeds 0.05%, the effect on the plating reliability is saturated and the cost is increased, which is not preferable. Therefore, Li, In, Ba,
One or more of Pd, Au, Pt, Rh, and Ir are defined as 0.0002 to 0.05%. The more preferable content of these components is 0.0006 to 0.03%, and it is more preferable to contain In, Pd and Au among these components.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION As raw materials, electrolytic copper, Cu-Mg
Mother alloy, Cu-Zn mother alloy, Ni, Cu-Si mother alloy,
Cu-P master alloy, Sn, Cu-Fe master alloy, Cu-Cr
A mother alloy, a Cu-Zr mother alloy and Pb are prepared, these raw materials are melted by using a low-frequency melting furnace in an ordinary reducing atmosphere, and Li, In, Ba, Pd, A is further added to the obtained molten metal.
u, Pt, Rh, Ir, etc. are added to adjust the composition,
The obtained Cu alloy molten metal is cast, and the present invention copper alloys 1 to 30 and the comparative copper alloys 1 to 1 having the component compositions shown in Tables 1 to 4 are cast.
2 and conventional copper alloy thickness: 80 mm, width: 20
A copper alloy ingot having a size of 0 mm and a length of 800 mm is manufactured, and the copper alloy ingot is heated in a reducing atmosphere at a temperature of 900-
A hot-rolled sheet with a thickness of 11 mm is obtained by annealing at a predetermined temperature within the range of 980 ° C. and then hot-rolling. After water-cooling this hot-rolled sheet, both upper and lower surfaces are separated by 0.5 mm and both end portions are 3 mm
Each of the pieces that have been face-cut is cold-rolled at a rolling ratio of 87% to produce a cold-rolled sheet having a thickness of 1.3 mm.
Continuous annealing was performed under conditions of 50 ° C. and 7 to 15 seconds of holding, pickling and surface polishing were performed, and further cold rolling was performed at a rolling ratio of 77% to produce a cold rolled sheet having a thickness of 0.30 mm. .

These cold-rolled sheets were continuously annealed at a predetermined temperature in the range of 710 to 780 ° C. for 7 to 15 seconds, and then in the temperature range of 710 to 500 ° C. at a cooling rate of 30 ° C./second or more. Cooled solution treatment, followed by 43
Precipitation treatment of holding at a predetermined temperature within a range of 0 to 470 ° C. for 3 hours is performed, and after pickling treatment, cold rolling is performed at a rolling ratio of 20% to obtain a cold rolled plate having a thickness of 0.24 mm. Finally, at a predetermined temperature within the range of 250 to 350 ° C, 25 to
Continuous strain relief annealing was carried out by passing a sheet for a predetermined time within a range of 30 seconds to produce a thin sheet.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

With respect to the obtained thin plates of the present invention copper alloys 1 to 30, comparative copper alloys 1 to 12 and conventional copper alloys, J
Tensile strength and elongation are measured according to IS / Z2241, and conductivity is measured according to JIS / H0505.
The results are shown in Tables 5 to 8.

Next, thin plates made of the copper alloys 1 to 30 of the present invention, the comparative copper alloys 1 to 12 and the conventional copper alloy were subjected to alkali degreasing, electrolytic degreasing and pickling, and a plating bath composition: nickel sulfate: 250 g / l. , Nickel chloride: 45 g / l, boric acid: 35 g / l, plating bath temperature: 45 ° C., current density: 4 A / dm ² , Ni undercoating was performed, and thickness: 0.3 ± 0.1
A Ni-underplated material having a thickness of μm was prepared, and the heat-resistant peeling property of the Ni-underplated material was evaluated.
It was shown to.

For the evaluation of the heat-resistant peeling property, a Ni undercoat material was cut into a width of 10 mm and a length of 50 mm to prepare a test piece, and the test piece was held in a vacuum of 3 × 10 ^-2 mmHg. After enclosing in a glass tube, annealing the enclosed test piece for 500 hours at 180 ° C., taking out from the glass tube, and performing 180 ° contact bending processing on each test piece,
The operation of bending back by 180 ° was performed again, and the presence or absence of peeling of plating at the 180 ° bent portion was observed.

Next, the Ni undercoat material was plated with the following composition: plating bath composition: stannous sulfate: 40 g / l, sulfuric acid: 110
g / l, cresol sulfonic acid: 25 g / l, additive:
7 g / l, plating bath temperature: 20 ° C., current density: 3 A / dm ² , thickness: 1.0 ± 0.2 μm Sn finish plating, then washing with water, drying, etc. Sn
A plated material was prepared, and this Ni-base Sn plated material was annealed at 180 ° C. for 1000 hours in the atmosphere. The annealed Ni-base Sn plated material was measured for stress relaxation rate to evaluate heat-resistant creep properties, Further, the increase in contact resistance before and after high temperature heating was measured, and the results are shown in Tables 5 to 8.

Regarding the heat-resistant creep property, the Ni-base Sn plated material was cut out and the width: 12.7 mm, length:
A test piece having a size of 120 mm (hereinafter, referred to as L ₀ ) was prepared, and this test piece had a length of 110 mm and a depth of 3 m.
Curvedly set so that the central part of the test piece bulges upward in a jig having a horizontal vertical groove of m (distance between both ends of the test piece at this time: 110 mm is L ₁ ) and in this state The temperature was kept at 180 ° C. for 1000 hours, and after heating, the distance (hereinafter referred to as L ₂ ) between both ends of the test piece which can be placed in a state of being removed from the jig was measured, and a calculation formula: (L ₀ − L
₂ ) / (L ₀ −L ₁ ) × 100% The stress relaxation rate was calculated to obtain the evaluation.

Regarding the increase of contact resistance, the Ni underlayer Sn was used.
A test piece was prepared by cutting out the plated material to have a width of 40 mm and a length of 40 mm, and the tip of this test piece was gold-plated with a diameter of 3 mm and a probe with a localized radius of 1.5 mm. The test piece was brought into contact with the surface of the test piece and the contact resistance was measured 10 times. Next, temperature: 100 to 180 ℃
The contact resistance after 0 hour holding and heating was measured 10 times under the same conditions, and the average difference in contact resistance before and after heating was determined as the increase in contact resistance.

[0030]

[Table 5]

[0031]

[Table 6]

[0032]

[Table 7]

[0033]

[Table 8]

From the results shown in Tables 1 to 8, Li, I
The copper alloys 1 to 30 of the present invention containing 0.0002 to 0.05% of one or more of n, Ba, Pd, Au, Pt, Rh, and Ir are Li, In, Ba, Pd, and Au,
Compared with a conventional copper alloy containing no Pt, Rh, or Ir,
Has almost the same tensile strength, elongation and conductivity, and
It has almost the same heat creep property as it has almost the same stress relaxation rate, but it is particularly excellent in heat-resistant peeling property, and it is understood that the contact resistance before and after heating at a high temperature is small.

[0035]

As described above, the copper alloy of the present invention has the same tensile strength, elongation, conductivity and conductivity as those of conventional copper alloys.
Despite having thermal creep strength, it has excellent heat-resistant peeling resistance and little increase in contact resistance before and after high-temperature heating, and the connector made from the copper alloy of the present invention can be used under severe high-temperature environment such as around automobile engine. In this case, no trouble such as dropping out occurs, and an excellent industrial effect is brought about.

Claims (4)

[Claims] 1. Ni: 0.5 to 3% by weight, Si: 0.0
8 to 0.7% by weight, Sn: 0.1 to 0.9% by weight, Z
n: 0.1 to 3% by weight, Fe: 0.007 to 0.25% by weight, P: 0.001 to 0.2% by weight, Mg: 0.00
1 to 0.2% by weight, Pb: 0.001 to 0.01% by weight
And further contains one or more of Li, In, Ba, Pd, Au, Pt, Rh and Ir in a total amount of 0.000.
A copper alloy having an excellent plating adhesion, which has a composition containing 2 to 0.05% by weight and the balance being Cu and inevitable impurities. 2. Ni: 0.5 to 3% by weight, Si: 0.0
8 to 0.7% by weight, Sn: 0.1 to 0.9% by weight, Z
n: 0.1 to 3% by weight, Fe: 0.007 to 0.25% by weight, P: 0.001 to 0.2% by weight, Mg: 0.00
1 to 0.2% by weight, Pb: 0.001 to 0.01% by weight
And further contains one or more of Li, In, Ba, Pd, Au, Pt, Rh and Ir in a total amount of 0.000.
2 to 0.05% by weight, Cr: 0.01 to 0.3% by weight, the balance being Cu and unavoidable impurities, and excellent plating adhesion. Copper alloy. 3. Ni: 0.5 to 3% by weight, Si: 0.0
8 to 0.7% by weight, Sn: 0.1 to 0.9% by weight, Z
n: 0.1 to 3% by weight, Fe: 0.007 to 0.25% by weight, P: 0.001 to 0.2% by weight, Mg: 0.00
1 to 0.2% by weight, Pb: 0.001 to 0.01% by weight
And further contains one or more of Li, In, Ba, Pd, Au, Pt, Rh and Ir in a total amount of 0.000.
2 to 0.05% by weight, Zr: 0.01 to 0.3% by weight, and the balance of Cu and inevitable impurities. Copper alloy. 4. Ni: 0.5 to 3% by weight, Si: 0.0
8 to 0.7% by weight, Sn: 0.1 to 0.9% by weight, Z
n: 0.1 to 3% by weight, Fe: 0.007 to 0.25% by weight, P: 0.001 to 0.2% by weight, Mg: 0.00
1 to 0.2% by weight, Pb: 0.001 to 0.01% by weight
And further contains one or more of Li, In, Ba, Pd, Au, Pt, Rh and Ir in a total amount of 0.000.
2 to 0.05% by weight, a total of 0.01 to 0.3% by weight of one or two of Cr and Zr, and a balance of Cu and inevitable impurities. A copper alloy having excellent plating adhesion, which is characterized by having.