JP2689507B2 - Cu alloy terminal and connector materials - Google Patents

Description

TECHNICAL FIELD The present invention relates to a Cu alloy terminal / connector material having particularly excellent spring properties and bending workability, as well as good conductivity, plating and solder adhesion. It is a thing.

[Conventional technology]

In general, materials used for manufacturing terminals, connectors, relays, switches and the like (hereinafter collectively referred to as terminals and connectors) include (a) a high spring for preventing contact pressure from decreasing due to fatigue or the like. (B) Good bendability to prevent cracks from occurring during bending, (c) High conductivity to eliminate voltage drop loss at the contact area, (d) Good plating and solder adhesion Since it is required to have the characteristics shown in the above (a) to (d), for example, Japanese Patent Laid-Open No. 61-183426, No. 3,
Cu alloys such as Cu-Ti-Zr alloys, Cu-Ti-Ni alloys, and Cu-Ti-Ni-Cr alloys described in Table 1 and Table 1 are used.

[Problems to be solved by the invention]

On the other hand, the recent miniaturization and high performance of electrical equipment have been remarkable, and accordingly, thinning and complicated shape of terminals and connectors, which are these structural members, have been strongly demanded.

However, the above-mentioned conventional Cu alloy terminal / connector material cannot satisfy these requirements at present because of its insufficient spring property and bending workability.

[Means for solving the problem]

Therefore, as a result of conducting research to develop a terminal / connector material excellent in spring property and bending workability from the above viewpoints, the present inventors have found that the terminal / connector material is % Indicates weight%), Ni: 1 to 3.5%, Ti: 0.3 to 1.5%, Cr: 0.2 to 1%, Zr: 0.05 to 0.5%, and Mg: 0.001 to 0.2%, Zr. : 0.05-0.5%, one or two of them, and the rest being composed of a Cu alloy having a composition of Cu and inevitable impurities, the resulting Cu alloy terminal / connector has excellent spring properties. It has been found that it has bending workability, and also has good strength, conductivity, and plating and solder adhesion.

The present invention has been made based on the above findings, and the reason why the component composition range is limited as described above will be described below.

(A) Ni and Ti These two components are combined to form an intermetallic compound (Ni _x Ti _y ) which is finely dispersed and precipitated in the crystal grains (in the base material), and thus the spring property is dramatically improved. Although it has an effect, if the content of either Ni or Ti is less than 1% for Ni and less than 0.3% for Ti, the precipitation amount of intermetallic compounds becomes insufficient, which is desirable. It is not possible to secure the excellent springiness of the alloy, while if either Ni or Ti exceeds 3.5% for Ni and 1.5% for Ti, it is excellent due to Cu as the main component. Since the conductivity will be impaired, the content should be Ni: 1 to 3.5.
%, Ti: 0.3 to 1.5%.

(B) Cr The terminal / connector material may be soldered during the manufacturing process. It is necessary that this solder does not peel off even when used in a high temperature environment. It has the function of improving the adhesiveness of the solder without impairing the excellent plating properties brought about by the main component Cu. That is, the Cr component diffuses into the interface between the base material and the solder layer, forming a barrier (barrier),
A compound layer that generally forms at the interface, such as Cu ₃ Sn (ε phase)
And Cu ₆ Sn ₅ (η phase) growth was significantly inhibited in, but with the effect of improving the adhesion of the solder with, the content is 0.2
If the content is less than 0.1%, the desired effect cannot be obtained, while if the content exceeds 1%, coarse Cr crystallized substances are generated and the adhesion of the plating is impaired. In addition, its melting and casting becomes difficult, so its content is set to 0.
Specified as 2-1%.

(C) Zr Zr component is an essential component for promoting the barrier action and the compound growth inhibiting action provided by the Cr component and ensuring the excellent solder peeling resistance.
In addition, in the Zr component, in addition to forming an intermetallic compound such as Cu ₃ Zr which is finely precipitated in the crystal grains and in the crystal grain boundaries by combining with Cu, the crystal grains are refined to improve the ductility. Bending workability is improved, and further, in the coexistence of the intermetallic compound of Cu ₃ Zr and the intermetallic compound of fine precipitation dispersion of Ni _x Ti _y , there is an action of further improving the spring property, but the content is 0.05. If it is less than 0.1%, the desired effect cannot be obtained, while if its content exceeds 0.5%, not only melting and casting become difficult, but also the plating adhesion is impaired by the generation of a large amount of inclusions. Therefore, the content was determined to be 0.05 to 0.5%.

(D) Mg and Zn These components have the effect of further improving the solder adhesion in the coexistence with Cr, but their contents are Mg:
If it is less than 0.001% and Zn: less than 0.05%, the desired improving effect on the above action cannot be obtained. On the other hand, if its content exceeds Mg: 0.2% and Zn: 0.5%, the conductivity is remarkably reduced. Therefore, the content of Mg: 0.001-0.2%, Zn: 0.
It was set as 05-0.5%.

〔Example〕

Next, the Cu alloy terminal / connector material of the present invention will be described more specifically with reference to Examples.

Using a normal vacuum melting furnace, in a graphite crucible, 5 kg each of molten Cu alloy having the composition shown in Table 1 was melted, cast into a die, face-polished, hot forged and It is hot-rolled into a plate with a width of 150 mm and a thickness of 10 mm, and then this plate is held at a temperature of 980 ° C for 30 minutes and then subjected to a solution treatment by water-quenching, and then surface-shaved to a thickness of 8 mm In this state, cold rolling and intermediate annealing (temperature: held at 500 ° C for 1 hour) are repeatedly performed, and final rolling is performed at a rolling rate of 50% to obtain a cold rolled material having a plate thickness of 0.25 mm, and finally Temperature to this: 35
The present invention Cu alloy terminal / connector material (hereinafter referred to as the present invention material) 1 to 8 and comparative Cu alloy terminal / connector material (hereinafter referred to as the comparative material) by low-temperature annealing under the condition of holding at 0 ° C for 5 minutes ) 1, 2 and conventional Cu alloy terminal / connector materials (hereinafter referred to as conventional materials) 1 to 3 were manufactured.

The comparative materials 1 and 2 are those in which the content of the Mg or Zn component constituting the Cu alloy (marked with * in Table 1) is outside the range of the present invention, and the conventional material 1 3 to 3 are Cu-Ti-Zr alloys, Cu-Ti-Ni alloys, and Cu-described in JP-A-61-183426, page 3, page 1 described above.
It is composed of a Cu alloy having a composition equivalent to that of a Ti-Ni-Cr alloy.

Next, the invention materials 1 to 8 and the comparative material 1 obtained as a result
For the purpose of evaluating the spring property by measuring the strength, elongation, and electrical conductivity (IACS%) of 2, and the conventional materials 1 to 3,
The spring limit value was measured, and a bending test, a plating adhesion test, and a solder peeling resistance test were repeated to evaluate bending workability, plating adhesion, and solder adhesion, respectively.

The spring limit value was measured by the JIS-H3130 repeated flexure test.

In addition, repeated bending test, width: 10 mm × length: 200 mm ×
Thickness: 0.25mm dimension With the test piece held upright in the length direction, the lower part from the center is supported by a block (50 mm × 50 mm × 50 mm) with a chamfered 0.2 mm R at the corner from the surface side, The test piece center was used as a bent portion, and the test piece center was bent repeatedly by 90 °, and the number of times of bending until the test piece center bent portion was broken (90 ° bending was once) was measured.

Plating adhesion test, width: 35 mm × length: 100 mm × thickness: 0.
A sample with a size of 25 mm was electroplated with an average layer thickness of 2 μm and kept at a temperature of 400 ° C for 3 minutes, and then heat-treated for cooling, and there was no blister after heat treatment. Was observed.

Further, the solder peeling resistance test uses a eutectic solder having a composition of 63% Sn-37% Pb, width: 10 mm × length: 30 mm ×
Thickness: A sample with a dimension of 0.25 mm is immersed in a bath of the solder at 230 ° C to adhere the solder to the surface, and in this state, the temperature is 150 ° C for 1000 hours, and 100 ° C. At 10000
The heating temperature is 15 for 15 hours.
When the temperature was 0 ° C, the sample was taken out every 100 hours, and when the heating temperature was 100 ° C, the sample was taken out every 1000 hours, and the interface (cross section) between the sample and the solder was observed with an optical microscope to check the peeling occurrence time. Table 2 shows the results.

〔The invention's effect〕

From the results shown in Tables 1 and 2, the present invention materials 1 to 8 are particularly recent terminal / connector materials as compared with the conventional material 3 having the best characteristics among the conventional materials 1 to 3. Excellent in spring property and bending workability as well as excellent elongation and solder adhesion, and also superior in strength, spring property, bending workability, and solder adhesion compared with conventional materials 1 and 2. On the other hand, although it is inferior in conductivity to the conventional materials 1 to 3, there is no problem because it exhibits a conductivity of 50 IACS% or more required for the terminal / connector material, and as seen in the comparative materials 1 and 2, It is clear that when the content of Mg or Zn is out of the range of the present invention and becomes high, the electric conductivity is particularly lowered to 40 IACS% or less.

As described above, the Cu alloy terminal / connector material of the present invention sufficiently satisfies the required conductivity, plating adhesion, and solder adhesion, and further has excellent spring property and bending property. Since it has workability, it can be made thinner and more complicated in shape to cope with recent miniaturization and higher performance of electric devices, and can exhibit excellent performance.

Claims (1)

(57) [Claims] 1. Ni: 1 to 3.5%, Ti: 0.3 to 1.5%, Cr: 0.2 to 1%, Zr: 0.05 to 0.5%, and further Mg: 0.001 to 0.2%, Zn: 0.05 to 0.5%, 1 type or 2 types of them, and the balance is made of a Cu alloy having a composition of Cu and inevitable impurities (above weight%), which is excellent in spring property and bendability. Cu alloy terminal / connector material.