JPH04231430A - Electrifying material - Google Patents

Abstract

PURPOSE:To obtain an electrifying material having high electric conductivity and excellent in migration resistance by limiting O content in an alloy having a specific composition consisting of Be and Cu and also controlling the size of a precipitate resulting from ageing treatment. CONSTITUTION:In an alloy which has a composition consisting of, by weight, 0.1-3.0% Be and the balance Cu with inevitable impurities and further containing, if necessary, 0.001-5.0% of one or more elements among Ni, Fe, Co, Cr, Ti, Zn, Ag, Pb, Sn, Mg, Mn, Al, B, P, As, and Sb as accessory components, O content is regulated to <=20ppm and also the size of a precipitate due to ageing treatment is regulated to <=2mum. Further, it is preferable to regulate its crystalline grain size to <=30mum. By this method, the electrifying material having high electric conductivity, excellent in migration resistance, and improved in strength owing to the accessory components 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 research on migration, and have developed Be0.1 to 3.0 wt. %, or further subcomponents such as Ni, Fe, Co, Cr, Ti, Zn, A
g, Pb, Sn, Mg, Mn, Al, B, P, As, S
The total amount of one or more types from the group consisting of b is 0.001
The oxygen content of the alloy consisting of ~5.0 wt% and the balance Cu and unavoidable impurities is 20 ppm or less, and
The alloy is characterized in that precipitates due to aging treatment are present, the size of the precipitates is 2 μm or less, and 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, Be is an element that, when contained in copper and copper alloys, has the effect of suppressing the migration properties of copper and copper alloys.

Although the mechanism for suppressing the migration phenomenon is not clear, the presence of Be reduces the amount of Cu ions eluted, and the formation of Be compounds obstructs the conduction of electricity through the deposited Cu particles, thereby preventing the electrode from flowing. It is inferred that the migration phenomenon between them is suppressed.

[0007] The reason why the Be content is set to 0.1 to 3.0 wt% is that if the Be content is less than 0.1 wt%, there is no effect of suppressing the migration phenomenon, and if it exceeds 3.0 wt%, the migration phenomenon is 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.

Ni, Fe, Co, Cr, T as subcomponents
i, Zn, Ag, Pb, Sn, Mg, Mn, Al, B,
The reason for including one or more types from the group consisting of P, As, and Sb in a total amount of 0.001 to 5.0 wt% is to improve migration properties, improve strength by precipitation strengthening, solid solution strengthening,
It is added for the purpose of grain refinement, and Ni, Fe, Co, Cr, and Ti are added to improve migration performance.
, Zn can be expected to be added, all elements can be expected to improve strength, and Ni, Fe, and Co can be expected to refine fine grains.

However, if the amount of these elements added is 0.001
If it is less than wt%, there is almost no effect, and on the contrary, if it is less than 5.
This is because if it exceeds 0 wt%, workability deteriorates and electrical conductivity decreases significantly.

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 Be is captured as an oxide in the alloy, it does not contribute to improving migration properties. In other words, in alloys with an oxygen content exceeding 20 ppm, Be is likely to be treated as an oxide, and when Be oxide is generated, Be is likely to be further concentrated there, resulting in a rapid decrease in migration properties. be.

The reason why the crystal grain size is set to 30 μm or less is that when the crystal grain size becomes coarser than 30 μm, there is a tendency for workability to decrease and migration property to decrease as well.

0012

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

First, among the compositions shown in Table 1, No. 17, 1
The alloys of the present invention and comparative alloys except No. 8 were melted and cast in the air or in an inert atmosphere, face-faced and then hot-rolled. After descaling, cooling rolling and annealing were repeated to obtain a final rolling degree of 20.
A cold rolled plate with a thickness of 0.6 mm was obtained. After aging the material appropriately, the surface was polished with #1200 emery paper.

[0014]

[Table 1] The test materials thus obtained and commercially available brass and phosphor bronze (N
o. 17, 18) tensile strength for the 0.6 mm plate,
Elongation, electrical conductivity, and migration resistance were evaluated. The results are shown in Table 2. Migration resistance test material is 10m long.
The test material was cut into pieces of m×100 mm and set as a set of two pieces as shown in FIG. 1, and then 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.

[0015]

[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, it can be seen that in the alloys of the present invention, those with a high Be content provide high strength, those with a low Be content provide a highly conductive material, and both have good migration properties. Also No. The dependence on the crystal grain size can also be seen from the comparison of 3 and 4.

[0017] Also, No. 4 and no. 1 and no. 5 and no. From the comparison of 2, Ni, Fe, Co, T as subcomponents.
The effect of i, Zn on migration resistance can be seen.

As for the comparative alloy, No. Since No. 13 has too high a Be content, it has high strength and good migration resistance, but when producing a sample material, edge cracking occurs during cooling rolling and the conductivity is not very high. No.
No. 14 has a large precipitate diameter and has poor migration resistance. No. No. 15 has too many subcomponents and therefore has low conductivity. No. No. 16 had a high amount of 0, so it had poor migration resistance. No. Brass No. 17 is conventionally said to have good migration resistance, and although it has good migration resistance, its strength is low and its conductivity is not very high. No. No. 18 is phosphor bronze, but its strength, conductivity, and migration resistance are not very good.

[0019]

[Effects of the Invention] The current-carrying material of the present invention has high strength, high conductivity, and excellent migration resistance, and is used for lead frames, automobile terminals, connectors, bus bars, etc. that require migration resistance. Applicable to electrically conductive materials.

[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: Contains 0.1 to 3.0 wt% of Be,
A current-carrying material characterized in that the zero content of an alloy consisting of the balance Cu and unavoidable impurities is 20 ppm or less, and there are precipitates due to aging treatment, and the size of the precipitates is 2 μm or less. [Claim 2] Contains 0.1 to 3.0 wt% of Be,
Ni, Fe, Co, Cr, Ti, Zn, A as subcomponents
g, Pb, Sn, Mg, Mn, Al, B, P, As, S
The total amount of one or more types from the group consisting of b is 0.001
-5.0 wt%, the balance is Cu and unavoidable impurities, the zero content of the alloy is 20 ppm or less, and there are precipitates due to aging treatment, and the size of the precipitates is 2
An electrically conductive material characterized by having a diameter of μm or less. 3. The electrically conductive material according to claim 1 or 2, wherein the crystal grain size is 30 μm or less.