JPH0920943A - Copper alloy for electronic and electrical parts and its production - Google Patents

Abstract

PURPOSE: To produce a copper alloy for electronic and electrical parts, excellent in bendability and having high strength and high electric conductivity. CONSTITUTION: This alloy is a copper alloy for electronic and electrical parts, which has a composition consisting of, by weight, 0.1-3.0% Co, 0.3-1.0% Si, 0.3-1.0% Zn, 0.005-0.1% Mn, 0.005-0.1% P, and the balance copper with inevitable impurities and in which compounds of Co and Si and compounds of Co and P exist in a base phase and the average crystalline grain size of the base phase is regulated to <=20m and, further, the aspect ratio of sheet-thickness direction to rolling direction is regulated to 1-3. This copper alloy for electronic and electrical parts is produced by performing, in succession, hot rolling, cold rolling at >=85% draft, annealing at 450-480 deg.C for 5-30min, cold rolling at <=30% draft, and aging treatment at 450-500 deg.C for 30-120min.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy having excellent bending workability, high strength and high conductivity for electronic and electrical parts and a method for producing the same, and particularly to a lead frame having a small size and a high density. The present invention relates to a copper alloy suitable for terminals, connectors, etc. and a method for manufacturing the same.

[0002]

2. Description of the Related Art Terminals and connectors used in electronic and electrical parts are becoming smaller and lighter as electronic and electrical equipments are becoming smaller.
High strength and high conductivity are desired. In order to satisfy these requirements, Cu-Ni-Si alloys have come to be used. Also, because the lead strength was improved,
Copper alloys can now be used in lead frame materials for highly integrated circuits.

[0003]

However, the conventional Cu-
Ni-Si alloys, when heat-treated under conditions that show the highest strength during the aging treatment, will undergo grain boundary cracking and / or metallographic cracking when terminals, connectors, lead frames, etc. are bent during or after molding. Since bending cracks occur due to the occurrence of such shear bands, it was necessary to perform heat treatment under aging conditions that would cause overaging. Therefore, for small terminals,
The performance was not sufficient as a material for connectors and lead frames for high integration.

[0004]

As a result of various studies in view of the above, the present invention has developed a copper alloy for electronic and electrical parts which has excellent bending workability, high strength and high conductivity, and a method for producing the same. Is.

That is, claim 1 of the present invention provides Co: 0.1
~ 3.0 wt%, Si: 0.3-1.0 wt%, Zn:
0.3-1.0 wt%, Mn: 0.005-0.1 wt
%, P: 0.005 to 0.1 wt%, the balance being copper and unavoidable impurities, in a copper alloy, a compound of Co and Si and a compound of Co and P are present in the mother phase, and The copper alloy for electronic and electrical parts is characterized in that the average grain size of the phase is 20 μm or less and the aspect ratio in the plate thickness direction with respect to the rolling direction is 1 to 3.

According to claim 2 of the present invention, Co: 0.1
~ 3.0 wt%, Ni: 1.5-3.0 wt%, and C
o + Ni ≦ 4.5, Si: 0.3 to 1.0 wt
%, Zn: 0.3-1.0 wt%, Mn: 0.005-
In a copper alloy containing 0.1 wt% and P: 0.005 to 0.1 wt% and the balance being copper and inevitable impurities, a compound of Ni, Co and Si, Co, P and Ni in the matrix phase. A copper alloy for electronic and electrical parts, characterized in that a compound of P is present, the average grain size of the mother phase is 20 μm or less, and the aspect ratio in the plate thickness direction with respect to the rolling direction is 1 to 3.

According to claim 3 of the present invention, Co: 0.1
~ 3.0 wt%, Ni: 1.5-3.0 wt%, and C
o + Ni ≦ 4.5, Si: 0.3 to 1.0 wt
%, Zn: 0.3-1.0 wt%, Mn: 0.005-
In a copper alloy containing 0.1 wt% and Zr: 0.05 to 0.3 wt% and the balance copper and unavoidable impurities, in the parent phase, a compound of Ni, Co and Si and a compound of Cu and Zr are contained. Is present and the average grain size of the matrix is 20
A copper alloy for electronic and electrical parts, characterized in that the aspect ratio in the plate thickness direction with respect to the rolling direction is 1 to 3 μm.

According to claim 4 of the present invention, Ni: 1.5
~ 3.0 wt%, Si: 0.3-1.0 wt%, Zn:
0.3-1.0 wt%, Mn: 0.005-0.1 wt
%, Zr: 0.05 to 0.3 wt%, with the balance being copper and unavoidable impurities, a Ni-Si compound and a Cu-Zr compound are present in the mother phase, and The copper alloy for electronic and electrical parts is characterized in that the average grain size of the mother phase is 20 μm or less, and the aspect ratio in the plate thickness direction with respect to the rolling direction is 1 to 3.

According to claim 5 of the present invention, after hot rolling,
Cold rolling of 85% or more is performed at 450 to 480 ° C. for 5 to 5.
After annealing for 30 minutes, 30% or less cold rolling is performed, and further 4
The aging treatment is performed at 50 to 500 ° C. for 30 to 120 minutes, and the method for producing a copper alloy for electronic and electric parts according to claim 1.

[0010]

Next, the reason for adding the constituent elements in the alloy of the present invention and the reason for limiting the composition range will be explained. Co,
The addition of Si, P and Zr is carried out by heat treatment of Co-S.
This is for precipitating the i compound and the Co-P or Cu-Zr compound. This is because the Co-Si compound has an effect of suppressing the growth of crystal grains, and the Co-P or Cu-Zr compound has an effect of improving the strength in addition to the effect of suppressing the growth of the crystal grains. Any of the elements does not exhibit the above effect if the content is less than the composition range, and addition of more than the composition range is not preferable because it causes a crystallization phase during casting and causes casting cracks.

The addition of Zn is to prevent environmental deterioration after soldering. Therefore, the Zn content is 0.3 to 1.
The reason why the content is 0 wt% is that the effect is not sufficiently obtained when the content is less than 0.3 wt%, and the conductivity decreases when the content exceeds 1.0 wt%. The addition of Mn is to trap sulfur existing as impurities and prevent the occurrence of embrittlement cracking. Therefore, the Mn content is 0.005-0.1 wt%
The reason is that the effect is not obtained when the content is less than 0.005 wt% and the conductivity decreases when the content exceeds 0.1 wt%.

Ni forms a Ni-Co-Si compound together with Co, and also a Ni-P or Ni-Si compound, which can further improve the strength.
If it is less than 5 wt%, the formation of intermetallic compounds is small and the improvement in strength is small, and if it exceeds 3.0 wt%, the workability is deteriorated and the conductivity is lowered. Note that Co + Ni ≦
The reason why it is set to 4.5 is that if Co + Ni exceeds 4.5, the hot rolling property is poor.

The oxygen content of the copper alloy of the present invention is 5
It is desirable that the concentration is about 100 ppm. The reason for this is that the excessive oxygen content not only makes the manufacturing process difficult, but also deteriorates the properties such as strength, moldability, plating property, and solderability. Further, the more desirable oxygen content is 5
-10 ppm.

The reason why the grain size is limited to 20 μm or less is that when the grain size is larger than 20 μm, dislocations introduced during deformation pile up to the grain boundaries during bending, forming cells and cracking. This is because it is easy to start from. The size of the precipitate is preferably 100 nm or less, and 5
˜50 nm is more desirable, but not limited to this.

The aspect ratio specified in the present invention is
It is a numerical value obtained from (length of crystal grain in rolling direction) / (length of crystal grain in plate thickness direction). The larger this value is, the longer the crystal grain extends in the rolling direction. . In the present invention, the reason why the aspect ratio is limited to 1 to 3 is that when the aspect ratio exceeds 3, rotation of each crystal orientation is less likely to occur during deformation, so dislocation cells are concentrated in a part of grain boundaries. This is because grain boundaries are broken and shear bands are easily formed in the crystal grains, and intergranular fracture is caused and bending workability is deteriorated.

In the manufacturing method of the present application, after hot rolling, 8
After cold rolling at a working rate of 5% or more, 450-480 ° C
The reason for annealing for 5 to 30 minutes is to perform recrystallization and Co-P or Ni- by cold working and annealing after hot rolling.
This is because the precipitation of the P compound proceeds at the same time. However, the reason why the working rate is limited to 85% or more is that at a working rate of less than 85%, the frequency of occurrence of recrystallization nuclei becomes low and the crystal grains do not become fine. Moreover, the annealing condition is set to 450 to 4
The reason for limiting the temperature to 80 ° C. for 5 to 30 minutes is that when the annealing temperature exceeds 480 ° C., recrystallization proceeds rapidly and Co−
This is because the precipitation of P or Ni-P compound does not proceed at the same time and the crystal grains become coarse. Annealing time 30
This is because when the amount exceeds the limit, the crystal grains become coarser.
Further, if the annealing temperature is less than 450 ° C. or the annealing time is less than 5 minutes, recrystallization does not occur sufficiently and the crystal grains do not become fine.

The reason why the cold rolling rate after annealing is set to 30% or less is that when the rolling rate exceeds 30%, the crystal grains extend in the rolling direction to increase the aspect ratio, or when the aging treatment is repeated. This is because crystals occur and a microcrystalline state cannot be obtained, and bending workability deteriorates.

The reason why the aging treatment is further carried out at 450 to 500 ° C. for 30 to 120 minutes is that Co--Si which improves the strength.
This is for sufficiently precipitating the compound and / or the Ni-Co-Si compound, and the temperature exceeds 500 ° C, or 12
If it exceeds 0 minutes, the precipitated phase becomes coarse, so that sufficient strength cannot be obtained, and if it is less than 450 ° C. or less than 30 minutes, the amount of the generated precipitation phase is insufficient, which is required as an electronic / electrical component. This is because strength and conductivity cannot be obtained.

[0019]

Embodiments of the present invention will be described below.

Example 1 Ingots No. a to m having the composition shown in Table 1 were melted in an induction melting furnace to have a thickness of 20 m.
A sample having m, a width of 150 mm and a length of 300 mm was cast.
Then, the sample was heated to 980 ° C. and held for 3 hours, and then hot-rolled to a thickness of 10 mm or 3 mm. After hot rolling, double-sided surface grinding or pickling bubbling was performed to obtain a thickness of 8 mm or 2 mm, respectively. Next, each sample was subjected to cold rolling, annealing treatment, cold rolling, and aging treatment under the manufacturing conditions of the method A of the present invention shown in Table 2.

The samples thus obtained were subjected to a tensile test, a conductivity measurement, a V-shaped bending test, a crystal grain size measurement by a transmission electron microscope, and a shape investigation. In addition,
The average crystal grain size is the average value of the length of crystal grains in the rolling direction and the length of crystal grains in the plate thickness direction. Table 3 shows the results.
The samples (Comparative Examples 10 to 13) using the comparative alloys j to m in which any one of Co, Ni, Si, Zn, Mn, P, and Zr is larger than the range of the present invention (Comparative Examples 10 to 13) are all in the casting process or the heat treatment. No further treatment was performed because cracking occurred during the hot rolling process.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

As is apparent from Table 3, the invention examples Nos. 1 to 6 produced by the production method of the present invention using the alloys (ingots No. a to f) within the composition range of the present invention, All have a grain size of 20 μm or less and an aspect ratio of 3 or less,
The limiting conditions of claims 1 to 4 are satisfied. However, the above alloy shows a good value of r / t (bending radius of V block / plate thickness), which is an index of bendability, of 0.4 or less, and 8
A tensile strength of 00 N / mm ² or more and a high conductivity of 45% IACS or more can be obtained. On the other hand, the manufacturing method is within the scope of the present invention, but the alloy composition is out of the claimed range.
Nos. 9 to 9 have poor tensile strength and 0.2% proof stress, and coarsening of crystal grains (outside the scope of the invention of claims 1 to 4), resulting in poor bendability.

Example 2 Of the ingots shown in Table 1, ingot N
Using o.a, melting, casting, heat treatment, hot rolling, double-sided surface grinding, pickling bubbling were performed under the same conditions as in Example 1, and each of the conditions (AM) shown in Table 2 was used. Treated.

The treated sample was subjected to a tensile test, a conductivity measurement, a V-shaped bending test, a crystal grain size measurement by a transmission electron microscope, and a shape investigation. Table 4 shows the results.
Shown in

[0028]

[Table 4]

As is apparent from Table 4, the particles obtained by the method of the present invention (Examples 14 to 16 of the present invention) have a grain size of 20 μm or less and an aspect ratio of 3 or less, and satisfy the limiting conditions of claims 1 to 4. ing. However, in the above-mentioned present invention example, r / t (bending radius of V block / plate thickness), which is an index of bendability, shows a good value of 0.4 or less, and further, tensile strength of 800 N / mm ² or more, And high conductivity of 45% IACS or more is obtained. On the other hand, when the manufacturing conditions were out of the claimed range (Comparative Examples 17 to 26), the crystal grains and the aspect ratio were out of the range of the present invention, the bendability was poor, and the tensile strength, proof stress, and conductivity were also It is inferior to the inventive examples.

[0030]

As described in detail above, according to the present invention, a copper alloy excellent in both strength and conductivity and excellent in bendability, which is a very important property as a material for electronic and electrical parts, is obtained. It is possible to provide a copper alloy for electronic / electrical components, which can sufficiently correspond to a material for electronic / electrical components that is highly integrated or miniaturized.

Claims (5)

[Claims] 1. Co: 0.1-3.0 wt%, Si: 0.
3 to 1.0 wt%, Zn: 0.3 to 1.0 wt%, M
n: 0.005 to 0.1 wt%, P: 0.005 to 0.
In a copper alloy containing 1 wt% and the balance consisting of copper and unavoidable impurities, a compound of Co and Si and a compound of Co and P are present in the mother phase, and the average grain size of the mother phase is 20 μm or less, A copper alloy for electronic and electrical parts, which has an aspect ratio of 1 to 3 in the plate thickness direction with respect to the rolling direction. 2. Co: 0.1 to 3.0 wt%, Ni: 1.
5 to 3.0 wt% and Co + Ni ≦ 4.5, S
i: 0.3-1.0 wt%, Zn: 0.3-1.0 wt
%, Mn: 0.005-0.1 wt%, P: 0.005
In a copper alloy containing 0.1 to 0.1 wt% and the balance copper and unavoidable impurities, Ni, Co and Si are contained in the matrix.
And a compound of Co and P, a compound of Ni and P,
And the average grain size of the matrix is 20 μm or less, and the aspect ratio in the plate thickness direction with respect to the rolling direction is 1 to 3, a copper alloy for electronic and electrical parts. 3. Co: 0.1 to 3.0 wt%, Ni: 1.
5 to 3.0 wt% and Co + Ni ≦ 4.5, S
i: 0.3-1.0 wt%, Zn: 0.3-1.0 wt
%, Mn: 0.005-0.1 wt%, Zr: 0.05
In a copper alloy containing 0.3 to 0.3 wt% and the balance copper and unavoidable impurities, Ni, Co and Si are contained in the matrix.
Alloy of Cu and Zr and the average grain size of the parent phase is 20 μm or less, and the aspect ratio in the plate thickness direction with respect to the rolling direction is 1 to 3; . 4. Ni: 1.5 to 3.0 wt%, Si: 0.
3 to 1.0 wt%, Zn: 0.3 to 1.0 wt%, M
n: 0.005-0.1 wt%, Zr: 0.05-0.
In a copper alloy containing 3 wt% and the balance being copper and inevitable impurities, a compound of Ni and Si and a compound of Cu and Zr are present in the matrix, and the average grain size of the matrix is 20 μm or less. A copper alloy for electronic and electrical parts, which has an aspect ratio of 1 to 3 in the plate thickness direction with respect to the rolling direction. 5. Hot rolling, cold rolling at 85% or more, annealing at 450 to 480 ° C. for 5 to 30 minutes, cold rolling at 30% or less, and further 30 to 450 to 500 ° C. 1
The aging treatment is performed for 20 minutes, and the aging treatment is performed.
A method for producing a copper alloy for electronic and electrical parts as described above.