JPH0672277B2 - Copper alloy for conductive material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has excellent compatibility with molten Sn and solder such as terminals, connectors, bus bars for automobile junction blocks, fuse materials for automobiles, lead frames and lead materials. And a copper alloy suitable for a conductive member.

[Prior art]

Conventionally, phosphor bronze, low alloy copper, or brass has been used as the member for electric parts. The characteristics commonly required for these members are that they have good compatibility with Sn or solder as seen in solderability, high electrical conductivity, sufficient strength, and corrosion resistance. is there. With respect to these required characteristics, phosphor bronze, low alloy copper and brass each have the following drawbacks. That is, phosphor bronze has problems in electrical conductivity and oxidation resistance. Further, low alloy copper such as copper containing Fe has the drawbacks that it is inferior in oxidation resistance out of corrosion resistance and that it is difficult to manufacture because it requires age hardening treatment. The term "oxidation resistance" as used herein refers to a heating and oxidation characteristic, but if the oxide film has poor properties, the insulation resistance against rainwater or the like decreases, and short circuit development due to corrosion called migration may occur.
Furthermore, brass has problems in compatibility with Sn or solder, electric conductivity, and stress corrosion cracking. Also, in terminals, connectors, bus bars, lead materials, etc., which are the fields of application of the present invention, the material generates heat due to Joule heat due to energization, but at this time, the plastic case must not be damaged. However, conventional materials such as phosphor bronze and brass have a problem in that heat generation becomes excessive due to their low electrical conductivity in response to the recent trend toward lighter, thinner, shorter, and smaller components and higher current densities associated with higher performance of components.

〔Purpose〕

The present invention has been made in view of the above problems, and an object thereof is to improve the drawbacks of the conventional copper alloy and to provide a copper alloy satisfying various conditions suitable as a member for electric parts. Is.

〔Constitution〕

The present invention contains Zn in an amount of more than 2.0% by weight and less than 5% by weight, Fe in an amount of more than 0.05% by weight and 1.0% by weight or less, P in an amount of 0.002% by weight or more and 0.1% by weight or less, and the balance of Cu and inevitable impurities. However, the alloy component makes it possible to combine the features of molten Sn or solder with good compatibility, relatively high electrical conductivity, high strength, and high corrosion resistance.

If we mention here the goodness of familiarity with Sn or solder in particular, it is obvious that it is preferable that the electrical component member has good familiarity when making contact with molten Sn or solder,
Familiarity refers to the low interfacial tension between Sn or solder and the copper alloy, which results in the spread of the solder material represented by the spread area and the speed at which the copper alloy material dissolves in Sn. Appears. And, the latter melting speed is the same as that of Sn disclosed in JP-A-60-211027.
This is a particularly important characteristic in a copper alloy high-heat material that is bonded together, and makes it possible to shorten the time from temperature rise to melting.

Next, the reasons for limiting the alloy components constituting the present invention will be described.

The Zn content is limited to more than 2.0% by weight and less than 5% by weight because if it is 2% or less, the oxidation resistance is insufficient and the melt castability becomes poor. This is because the ratio falls below 50% IACS, which gives unsuitable results for automotive fuses and electrical parts that carry high currents such as bus bars and terminals, and also deteriorates stress corrosion cracking resistance.

The Fe content is limited to more than 0.20 and 1.0% by weight or less because if it is 0.20% by weight or less, Fe gathers at the interface between the molten Sn or the solder and the copper alloy, and the interfacial tension decreases. The effect of Fe for improving the strength is not sufficient, and if it exceeds 1.0% by weight, the conductivity is lowered and the workability is lowered.

The P content is limited to 0.002% by weight or more and 0.1% by weight or less because when it is less than 0.002% by weight, the synergistic effect with Fe is exerted to improve the strength, the castability, or the familiarity with Sn or solder. The improvement effect is not enough, 0.1
If it exceeds 5% by weight, the conductivity and workability are deteriorated.

The alloy of the present invention contains 0.05% by weight or more and 2% by weight or less of Cr, Ni,
The strength can be improved by further adding at least one of Co, Mg, Mn, and Zr if necessary.

Examples will be shown below.

Example 1 The alloys of the present invention and comparative alloys shown in Table 1 were melted in a high-frequency melting furnace under a charcoal coating using a graphite crucible and die-cast. The obtained 35 × 90 × 150 mm ingot was face-polished to a thickness of 25 mm and hot-rolled at 800 ° C. to a thickness of 12 mm. After both sides of this plate were ground to a thickness of 10 mm, cold rolling and annealing were repeated to produce a test material with a final working rate of 20% and a plate thickness of 0.4 mm.

A test piece was cut out from this test material, and the tensile strength, elongation and conductivity were measured.

In order to check the compatibility with molten Sn or solder, the compatibility with solder material is the same as the compatibility with Sn.
I did two tests. The first is a test for examining the spreadability. The surface of each alloy is paper-polished and the flux (MIL
Applying RMA type that complies with the above standards and applying Sn (0.13g) 35
Sn was melted for 30 seconds in an atmosphere of 0 ° C., cooled, and the spread area was measured. The second is a test for investigating the dissolution rate of a copper alloy in molten Sn. A 0.4 x 20 x 50 mm test piece was cut out and immersed in Sn melted and held at 400 ° C for 30 seconds at the same time, and after taking out, embedding and polishing in each resin and measuring the thickness of each alloy after 30 seconds, dipping The difference from the previous thickness was measured and taken as the dissolved amount.

Also, two tests were performed to see the corrosion resistance. The first is a high temperature oxidation weight loss test. After polishing both sides of the sample cut into a size of 30 × 50 mm with # 1000 emery paper, 3 in air
It was heated at 50 ° C x 2 Hr. The produced oxide film was peeled off using 10% sulfuric acid and then weighed to determine the oxidation loss. Part 2
Is a stress corrosion cracking test. CuSO ₄ / 5H ₂ O 125 g / l, (NH ₄ ) ₂ S
A bending stress of 20 kg / mm ² was applied to Matson's liquid consisting of O ₄ 590 g / l and NH ₄ OH 71 ml / l, and the condition was maintained for 10 hours.

The results are shown in Table 2. The "x" in the stress corrosion cracking test indicates that the sample broke during this period.

As shown in Table 2, the alloy of the present invention is good in all of strength, conductivity, compatibility with solder, and corrosion resistance, but in Comparative Alloy 3 (low alloy copper), strength and oxidation loss are 4%.
(Red copper) has strength and dissolution amount, 5 (brass) has conductivity,
It can be seen that the spreading area, the amount of dissolution, and the stress corrosion cracking property of 6 (phosphor bronze) are inferior in the conductivity and the oxidation loss.

Example 2 As shown in Table 3, the alloy of the present invention and 2 wt%
A comparative alloy containing Sn was melted and processed in the same manner as in Example 1 to form a plate having a plate thickness of 0.4 mm, and then annealed at 400 ° C. for 1 hour to measure the electrical conductivity. The results are also shown in Table 3.

As described above, the Sn conductivity is greatly reduced.

〔effect〕

According to the present invention as described above, various properties such as good compatibility with molten Sn or solder, high electrical conductivity, high strength, and corrosion resistance, which are required as members for electric parts The effect is that a copper alloy for conductive members that satisfies all the characteristics can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 58-197244 (JP, A) JP 58-157931 (JP, A) JP 59-31839 (JP, A) JP 62- 136539 (JP, A)

Claims (1)

[Claims] 1. A Zn content of more than 2.0% by weight and less than 5% by weight, Fe of more than 0.20% by weight and 1.0% by weight or less, P of 0.002% by weight or more and 0.1% by weight or less, and the balance of Cu and inevitable impurities. , A copper alloy for conductive members that has excellent compatibility with molten Sn and solder.