JPH04231443A - Electrifying material - Google Patents

Abstract

PURPOSE:To produce an electrifying material excellent in migration resistance by specifying O content and the size of a precipitate resulting from ageing treatment, respectively, in a copper alloy containing specific percentages of Zr. CONSTITUTION:An alloy which has a composition consisting of, by weight, 0.05-1.0% Zr and the balance Cu with inevitable impurities or further containing, as accessory components, 0.001-5.0%, in total, of one or >=2 elements among Ag, Al, Au, B, Be, Co, Cr, Fe, Ga, Ge, Mg, Mn, Mo, Ni, P, Pb, Pt, Si, Sb, Sn, Ta, V, W, Zn, Hf, Nb, and Ti is prepared. This alloy is hot-rolled and cold rolling, annealing, and pickling are repeatedly done, and crystalline grain size is regulated and a cold rolling sheet of the prescribed thickness is formed, by which O content and the size of a precipitate resulting from ageing treatment are regulated to <=20ppm and <=2mu, respectively. By this method, the electrifying material having high strength and high electric conductivity and excellent in migration resistance can be obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current-carrying material for electrical parts that suppresses migration between lead frames, terminals, connectors, and bus bars (also referred to as bus bars).

0002

2. Description of the Related Art In recent years, electronic and electrical equipment, etc. have become smaller and lighter, and the parts used, such as connectors, have become smaller and the distances between parts have also tended to become significantly shorter. or,
Circuits are becoming increasingly integrated. In other words, in the past, individual electronic components were connected by lead wires to form a circuit, but as the number of components increases, circuits become more complex, so circuits are becoming smaller by integrating them. There is.

0003

[Problems to be Solved by the Invention] In conventional miniaturized and integrated circuits, different circuits or wiring are separated by a small interval for miniaturization, but there is a problem that water, etc. When an electrolyte is present, an electrochemical reaction occurs, and copper ions dissolved from the copper alloy that is the material of the current-carrying part on the high-potential side are deposited on the low-potential side, and when the amount increases further, a short circuit occurs. This phenomenon is called migration, and when such migration occurs, the circuit no longer functions properly. Therefore, in recent years, there has been a strong desire for materials that have high electrical conductivity and do not cause migration.

0004

[Means for Solving the Problems] In view of the above-mentioned problems, the present inventors have conducted migration research and have developed Zr0.05 to 1.0 wt as a conductive material for terminals, connectors, bus bars, etc. connected to the anode side. %, or further contains Ag, Al, Au, B, Be, Co, C as subcomponents.
r, Fe, Ga, Ge, Mg, Mn, Mo, Ni, P,
Pb, Pt, Si, Sb, Sn, Ta, V, W, Zn,
The alloy contains one or more from the group consisting of Hf, Nb, and Ti in a total amount of 0.001 to 5.0 wt%, the balance being Cu and unavoidable impurities, and the oxygen content is 20 ppm or less, and The alloy is characterized in that precipitates are present due to the treatment, and the size of the precipitates is 2 μm or less, and further, the crystal grain size of the alloy is 30 μm or less.

According to the present invention, the amount of each element added to Cu is determined in consideration of the following. That is, first of all, Zr is an element that has the effect of suppressing the migration property of copper and copper alloys by being contained in copper and copper alloys.

Although the mechanism for suppressing the migration phenomenon is not clear, the presence of Zr reduces the elution amount of Cu ions, and the generation of Zr compounds impedes the conduction of electricity through the deposited Cu particles. It is presumed that the migration phenomenon between them is suppressed.

[0007] The reason why the Zr content is set to 0.05 to 1.0 wt% is that if the Zr content is less than 0.05 wt%, it will not be effective in suppressing the migration phenomenon, and if it exceeds 1.0 wt%, the migration phenomenon will not be suppressed. This is because although it is effective, the conductivity decreases, the amount of heat generated when electricity is applied increases, and the heat dissipation performance also decreases.

[0008] Ag, Al, Au, B, Be as subcomponents
, Co, Cr, Fe, Ga, Ge, Mg, Mn, Mo,
Ni, P, Pb, Pt, Si, Sb, Sn, Ta, V,
One or two from the group consisting of W, Zn, Hf, Nb, and Ti
The reason why these elements are added in a total amount of 0.001 to 5.0 wt% is that these elements contribute to improving strength by forming intermetallic compounds with Zr or by solid solution in Cu. , the amount of these elements added is 0.001wt%
This is because if the content is less than 5.0 wt%, the effect will be low, and if it exceeds 5.0 wt%, the conductivity will be significantly reduced.

The reason why the size of the precipitates is limited to 2 μm or less is that if the precipitates become coarse and larger than 2 μm, the migration phenomenon is likely to occur rapidly. The reason why the oxygen content was set to 20 ppm or less was
This is because it has been found that if Zr is captured as an oxide in the alloy, it does not contribute to improving migration properties. In other words, in an alloy with an oxygen content exceeding 20 ppm, Zr is easily regarded as an oxide, and when Zr oxide is generated, Zr is likely to be further concentrated there, resulting in a rapid decrease in migration properties. be.

Furthermore, when the grain size becomes coarser and exceeds 30 μm, there is a tendency for workability to decrease and migration performance to decrease.
It is recommended that the thickness be 0 μm or less.

[0011]

[Example] Specific examples of the present invention are shown below.

First, the alloys of the present invention and comparative alloys having the compositions shown in Table 1 were melted and cast in an inert atmosphere, and hot-rolled after facing, and then cool-rolled, annealed, and pickled repeatedly.
The grain size is adjusted by final annealing at 00°C for a predetermined time,
After pickling, a plate with a thickness of 0.6 mm was obtained by cold rolling at a processing degree of 20%. Then, the surface was polished with #1200 emery paper.

[0013]

[Table 1] These test materials were evaluated for tensile strength, elongation, electrical conductivity, and migration resistance. The results are shown in Table 2. To test the migration resistance, the test material was cut into 10 mm x 100 mm pieces, set in pairs as shown in FIG. 1, and immersed in tap water (300 cc) as shown in FIG. Next, a DC voltage of 14 V was applied to these two test materials, and the change in current value with respect to elapsed time was measured using a recorder. A representative example of this result is shown in FIG. Further, Table 2 shows the time required for the current value to reach 1.0 A (arrow in FIG. 3) for each sample material.

[0014]

[Table 2] The size of the precipitates is 2 m when the cross section of the sample material is multiplied by 1000.
m2 was determined by examining the size of the largest precipitate.

From Table 2, the alloy No. of the present invention. All alloys 1 to 9 have a conductivity of 40% IACS or higher, have excellent strength and migration resistance, and are optimal as conductive materials for lead frames, automotive terminals, connector bus bars, etc. that require migration resistance. I understand. However, No. Sample No. 9 has a large crystal grain size of 60 μm, so the migration property is slightly deteriorated.

[0016] Also, comparative alloy No. Since No. 10 has a low Zr content, it has poor migration resistance and low strength. Comparative alloy No. No. 11 has too much Zr content, so its conductivity is low. Comparative alloy No. 12 is the invention alloy No.
Since the precipitates were too large compared to No. 3, migration resistance was poor. Comparative alloy No. 13 is the invention alloy No.
Since the oxygen content is higher than that of No. 3, migration resistance is poor. Comparative alloy No. 14 is a type of brass conventionally used for automobile bus bars, etc., and has high migration resistance but low electrical conductivity.

[0017]

[Effects of the Invention] The current-carrying material of the present invention has high strength, high conductivity, and excellent migration resistance.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a sample material for a migration resistance test.

FIG. 2 is an explanatory diagram of the test.

FIG. 3 is a graph showing migration resistance test results.

Claims (3)

[Claims] Claim 1: The alloy contains 0.05 to 1.0 wt% of Zr, the balance being Cu and unavoidable impurities, and the O content is 20 ppm or less, and there are precipitates due to aging treatment, and the precipitates are An electrically conductive material characterized by having a size of 2 μm or less. 2. Contains 0.05 to 1.0 wt% of Zr, and contains Ag, Al, Au, B, Be, Co, and C as subcomponents.
r, Fe, Ga, Ge, Mg, Mn, Mo, Ni, P,
Pb, Pt, Si, Sb, Sn, Ta, V, W, Zn,
The alloy contains one or more from the group consisting of Hf, Nb, and Ti in a total amount of 0.001 to 5.0 wt%, the balance being Cu and unavoidable impurities, and the O content is 20 ppm or less, and the aging treatment is performed. 1. An electrically conductive material characterized by the presence of precipitates caused by the above, and the size of the precipitates being 2 μm or less. 3. The electrically conductive material according to claim 1 or 2, wherein the crystal grain size is 30 μm or less.