JP2002003966A - Copper alloy for electronic and electric apparatus excellent in solder weldnability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper alloy capable of stably obtaining good solder weldability. SOLUTION: This copper alloy has a composition containing, by weight, 3.0 to 9.0% Sn and Fe, Ni and P by 0.05 to 1.0% in total, in which the atomic weight ratio of Fe, Ni and P shown by the formula of [(Fe+Ni)/P] is 0.2 to 3.0, and the balance Cu with inevitable impurities, and the number of P compounds with a diameter of 0.001 to 1 μm is >=100 pieces/mm. Since Sn, Fe, Ni and P are contained by suitable amounts, mechanism properties required for the material for electronic parts are satisfied, since the atomic weight ratio of Fe, Ni and P shown by the formula of [(Fe+Ni)/P] is prescribed to 0.2 to 3.0, and further, the number of P compounds with a diameter of 0.001 to 1 μm is prescribed to >=100 pieces/mm, most P is present as compounds and does not diffuse into the boundary of the solder joint, so that secular deterioration in the solder joinability can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy for electronic and electric equipment which can stably obtain good solderability.

[0002]

2. Description of the Related Art Electronic components such as connectors, terminals and relay switches used in electronic and electrical equipment and wiring in automobiles are made of iron-based materials or phosphor bronze having excellent electric and thermal conductivity.
Copper-based materials such as copper and brass are widely used, and solder is often used for joining the electronic components.

[0003]

The copper-based material, in particular,
It is known that the solderability of a copper alloy containing Sn and P is liable to deteriorate with time. The area tends to decrease. Under such circumstances, for copper-based materials, in order to improve solder jointability,
Various attempts have been made to increase the amount of solder and to improve the solder mounting technique, but no satisfactory effect has been obtained yet. Therefore, the present inventors conducted research on the improvement of the solder joint property of a copper alloy containing Sn and P, and the deterioration of the solder joint property with the lapse of time showed that P in the copper alloy diffused to the solder joint interface and the solder joint interface was deteriorated. The inventors have found that the purpose is to form an altered layer, and have conducted further studies to complete the present invention. SUMMARY OF THE INVENTION An object of the present invention is to provide a copper alloy for electronic and electrical equipment in which good solder jointability can be obtained stably.

[0004]

According to the first aspect of the present invention,
It contains 3.0 to 9.0 wt% of Sn and 0.05 to 1.0 wt% in total of Fe, Ni and P, and has an atomic weight of Fe, Ni and P represented by the formula of [(Fe + Ni) / P]. The ratio is 0.2 to 3.0, and the balance is a copper alloy composed of Cu and inevitable impurities, and the number of P compounds having a diameter of 0.001 to 1 μm distributed in the copper alloy is 100 / mm. It is a copper alloy for electronic and electrical equipment which is excellent in solderability, characterized by being ² or more.

According to a second aspect of the present invention, Zn is contained in a range of 5.0 to 4%.
0 wt%, Sn: 0.01 to 5.0 wt%, Fe, Ni
And P in total of 0.05 to 1.0 wt%, and the atomic weight ratio of Fe, Ni and P represented by the formula [(Fe + Ni) / P] is 0.2 to 3.0, and the balance is A copper alloy comprising Cu and unavoidable impurities, wherein the number of P compounds having a diameter of 0.001 to 1 μm distributed in the copper alloy is 100 / mm ² or more, and is excellent in solder jointability. It is a copper alloy for electronic and electrical equipment.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a method for converting P into a compound,
The diffusion is suppressed, and thus the deterioration with time of the solder joint property is improved. The copper alloy according to claim 1,
Sn, Fe, Ni, and P contribute to the improvement of mechanical properties, and P also plays a deoxidizing effect. The content of Sn is 3.0 to 3.0.
The reason for setting the content to 9.0 wt% and the total content of Fe, Ni and P to 0.05 to 1.0 wt% is that even if any of them is less than the lower limit, the effect is not sufficiently obtained, and This is because even if the upper limit value is exceeded, the manufacturing processability decreases.

In the present invention, the atomic weight ratio of Fe, Ni and P expressed by the formula [(Fe + Ni) / P] is set to 0.1.
The reason that the atomic weight ratio is less than 0.2 is that P, such as Fe-P, Ni-P, or Fe-Ni-P,
This is because Fe or Ni which does not become a P compound when the compound is not sufficiently formed and exceeds 3.0 does not form a solid solution in the copper alloy and lowers the conductivity of the copper alloy.

In the present invention, the diameter is 0.001-1.
The reason why the number of P compounds of μm is defined to be 100 / mm ² or more is that if it is less than 0.001 μm, the P compound is unstable and P is likely to be dissolved again in the copper alloy. This is because it becomes the origin of cracking when it is formed into a part, and if the amount of the P compound is less than 100 / mm ² , the amount of dissolved P increases and the soldering property deteriorates with time. . In the present invention, the size and the number of the P compounds are values measured by photographing the corroded surface with an electron microscope (SEM) and corroding the surface of the copper alloy material.

According to the first aspect of the present invention, Sn is set to 3.0 to 3.0.
Commercially available JIS-C5111, JIS containing 9.0 wt%
-C5102, JIS-C5191, JIS-C521
It is simple and economical to use 2 or the like.

According to a second aspect of the present invention, a part of Sn of the copper alloy according to the first aspect of the present invention is replaced with Zn.
Contributes to the improvement of the mechanical properties like Sn, and also improves the solder fluidity. Zn content of 5.0 to 40 wt%
The reason is that if the content is less than 5.0% by weight, the effect cannot be sufficiently obtained, and if the content exceeds 40% by weight, the processability in manufacturing is reduced. According to the second aspect of the present invention, F
The functions and effects of e, Ni and P are the same as those described in the first aspect.

[0011] The copper alloy of the present invention can be produced by a conventional method of performing melt casting, homogenization treatment, face milling, hot rolling, and cold rolling including intermediate annealing. In the present invention, the number of P compounds having a diameter of 0.001 to 1 μm is defined as 100 / m.
As a method of dispersing the particles to m ² or more, for example, there is a method of defining intermediate annealing conditions before final cold rolling. In the intermediate annealing, it is recommended that heating be performed at a temperature of 400 to 800 ° C. for about 20 minutes to 4 hours. In the copper alloy of the present invention, the same effect is exhibited whether the solder is ordinary Pb-Sn solder or Pb-free solder.

[0012]

The present invention will be described below in detail with reference to examples. (Example 1) Various Cu-Sn-Fe-Ni-P alloys within the composition range specified in the first aspect of the present invention are melted by a high-frequency melting furnace, and are melted at a cooling rate of 10 to 30 ° C / sec.
Cast C, thickness 30mm, width 100mm, length 150m
m was obtained. Of these ingots, the ingot with a Sn content of 5.0 wt% or more was subjected to a homogenization treatment of heating at 800 ° C. for 1 hour, then slowly cooled, and then both surfaces were ground to remove an oxide film. And then cold rolled to a thickness of 1.2 m
m, and heat-treated at 700 ° C. for 1 hour in an inert gas atmosphere, then cold-rolled, and then 400 to 6
After heat treatment at 00 ° C. for 0.01 to 1 hour, a final cold rolling was performed to produce a 0.25 mm thick plate.

[0013] The ingot having a Sn content of less than 5.0 wt% is subjected to a reheat treatment at 900 ° C for 0.5 hours in an inert gas, and hot-rolled to a thickness of 10 mm as it is. After chamfering both surfaces, the plate was cold-rolled into a sheet having a thickness of 1.2 mm, which was then heat-treated at 700 ° C. for 1 hour in an inert gas atmosphere, and then cold-rolled.
After heat treatment at 00 ° C. for 0.01 to 1 hour, a final cold rolling was performed to produce a 0.25 mm thick plate.

(Example 2) Various Cu-Zn-Sn-Fe-Ni-P within the composition range specified in the second aspect of the present invention.
Except that an alloy was used, the same method as in Example 1 was applied to obtain a thickness of 0.1 mm.
A 25 mm plate was produced.

Comparative Example 1 A thickness of 0.25 m was obtained in the same manner as in Example 1 except that various Cu-Sn-Fe-Ni-P alloys outside the composition range specified in the first aspect of the present invention were used.
m plate material was manufactured.

(Comparative Example 2) Various Cu-Zn-Sn-Fe-Ni-P outside the composition range specified in the second aspect of the present invention.
Except that an alloy was used, the same method as in Example 2 was applied to a thickness of 0.1 mm.
A 25 mm plate was produced.

The solder bonding properties of the respective plates manufactured in Examples 1 and 2 and Comparative Examples 1 and 2 were examined by the following method. That is,
As shown in FIG. 1 (a), a 20 mm × 20
mm of a test material 1 was cut out, and a seal 2 having a hole a of 5 mmφ was stuck on one side, and a 5 mmφ
Aluminum solder holding jig (50 ×
50 × 5 mm) 3 is arranged with the hole a and the hole b matched.
A molten solder 4 is placed in the holes a and b, and an EF wire of 2 mmφ (Cu-coated Fe wire, length 100 mm) is placed on the molten solder 4.
5, the EF wire 5 is held perpendicular to the test material 1, and after the molten solder 4 solidifies, the solder holding jig 3 and the seal 2 are removed, and the tensile test material shown in FIG. 6 was obtained. The EF wire 5 is about 2
mm was bent at a right angle.

Each of the tensile test materials 6 thus obtained was heated in the air at 150 ° C. for 1000 hours, and then subjected to a tensile test to measure the breaking strength t. Ratio S to T = (t / T) × 100%
Was determined, and the solder jointability was determined. The larger the S value is, the more excellent the solder bonding property is. The tensile test was performed on the test material 1
And the EF wire 5 were each held by a dedicated chuck. Most of the fractures in the tensile test were solder joint surfaces. In addition,
The number of P compounds was determined by corroding the surface of the test material with a dilute acid (sulfuric acid + hydrogen peroxide) for about 30 seconds, taking a photograph at a magnification of 500 to 2000 times with an electron microscope (SEM), The number of 0.001 to 1 μm P compounds was counted. The results are shown in FIGS.

FIG. 2 shows the relationship between the total content of Fe, Ni and P and the S value. When the total content of Fe, Ni, and P is in the range of 0.05 to 1.0 wt%, the S value is Cu.
In the case of -Sn-based alloy, it was 40-67%, and in the case of Cu-Zn-Sn-based alloy, it was 54-80%, showing good solderability. The total content of Fe, Ni and P is 0.05 to 1.0
Outside the range of wt%, the S value sharply decreased. Here, the ratio of (Fe + Ni) / P was in the range of 0.2 to 3.0.

FIG. 3 shows the ratio of (Fe + Ni) / P and S
The relationship between the values is shown. (Fe + Ni) / P ratio is 0.2
Within the range of ~ 3.0, the S value is 30-67% for the Cu-Sn-based alloy and 4 for the Cu-Zn-Sn-based alloy.
6 to 80%, indicating good solder jointability. (Fe
When the ratio of (+ Ni) / P was out of the range of 0.2 to 3.0, the S value sharply decreased. Here, the total content of Fe, Ni, and P was in the range of 0.05 to 1.0 wt%.

FIG. 4 shows a P having a diameter of 0.001 to 1 μm.
The relationship between the number of compounds and the S value was shown. When the number of the P compounds is 100 or more, the S value is 31 to 67% in the case of the Cu-Sn-based alloy and 46 in the case of the Cu-Zn-Sn-based alloy.
~ 80%, indicating good solderability. When the number of P compounds was less than 100, the S value was reduced to 28% or less.
Here, the ratio of (Fe + Ni) / P is 0.2 to
Within the range of 3.0, the total content of Fe, Ni, and P is 0.0
The content was in the range of 5 to 1.0 wt%.

Each of the copper alloy sheets of the present invention produced in Example 1 was examined for mechanical properties, electrical conductivity, stress relaxation properties, bending workability, etc., all of which were required as materials for electronic parts. Was satisfied.

[0023]

As described above, since the copper alloy according to the first aspect of the present invention contains Sn, Fe, Ni and P in appropriate amounts, the mechanical properties required for the material for electronic parts are satisfied. And ([Fe + N] of Fe, Ni and P
i) / P] is defined as 0.2 to 3.0, and the number of P compounds having a diameter of 0.001 to 1 μm is defined as 100 / mm ² or more. Most of them are present as compounds and do not diffuse to the solder joint interface, so that the deterioration with time of the solder joint is suppressed. The copper alloy according to the second aspect of the invention further contains an appropriate amount of Zn, and has the same effect as the copper alloy according to the first aspect of the invention. Therefore, the copper alloy of the present invention can be used for electronic components such as connectors, terminals, and relay switches, so that good solder bonding properties can be stably obtained, and have a remarkable industrial effect.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory diagrams of a method for measuring a solder joint strength. FIG.

FIG. 2 is a diagram showing the relationship between the S value and the total content of Fe, Ni and P.

FIG. 3 is a relationship diagram between an S value and a ratio of ((Fe + Ni) / P).

FIG. 4 is a graph showing the relationship between the S value and the number of P compounds.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 sample material 2 seal 3 solder holding jig 4 molten solder 5 EF wire 6 tensile test material 7 solder

Claims (2)

[Claims] 1. An alloy containing Sn in an amount of 3.0 to 9.0 wt%, Fe, N
i and P are contained in a total amount of 0.05 to 1.0 wt%, and the atomic weight ratio of Fe, Ni and P represented by the formula [(Fe + Ni) / P] is 0.2 to 3.0, and the balance is Is Cu
And a copper alloy comprising unavoidable impurities, wherein the number of P compounds having a diameter of 0.001 to 1 μm distributed in the copper alloy is not less than 100 / mm ² , and is excellent in solder jointability. Copper alloy for electrical equipment. 2. A Zn content of 5.0 to 40 wt% and a Sn content of 0.
01 to 5.0 wt%, Fe, Ni and P are added in a total amount of 0.1 to 5.0 wt%.
And the atomic weight ratio of Fe, Ni and P represented by the formula [(Fe + Ni) / P] is 0.1 to 1.0 wt%.
2 to 3.0, the balance being a copper alloy composed of Cu and unavoidable impurities, wherein the number of P compounds having a diameter of 0.001 to 1 μm distributed in the copper alloy is 100 / mm.
^A copper alloy for electronic and electrical equipment having an excellent solderability, characterized in that it is ² or more.