JPH02190431A - Copper alloy for connecting apparatus - Google Patents

Abstract

PURPOSE:To obtain the copper alloy having excellent strength, electrical conductivity, platability, solderability, stress relaxation properties, fatigue properties, bendability, corrosion resistance, etc., by specifying the compsn. constituted of Ni, Si, P, O2, S and Cu. CONSTITUTION:The copper alloy for a connecting apparatus contains, by weight, 1.5 to 6.0% Ni, 0.1 to 3.0% Si, 0.12 to 1.0% P, <=20ppm O2 and <=10ppm S, furthermore contains, at need, <=5.0% Zn and total <=1.0% of one or more kinds among <=0.6% Mg, <=0.6% Mn, <=0.35% Cr, <=0.1% V, <=0.35% Ti and <=0.6% Co and the balance Cu with inevitable impurities. The alloy has excellent practical properties as connecting parts. The above alloy can be obtd. by subjecting a copper alloy having prescribed compsn. to hot working, to rapid cooling, thereafter combinedly repeating cold working and aging treatment to the alloy and finely and dispersedly precipitating intermetallic compounds or the like therein.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is suitable for use as connecting parts inside and outside electronic and electrical equipment, particularly IC sockets, connectors, outlets, switches, relays, contact springs, terminals, etc.

Conductivity, plating properties, solderability, and stress relaxation properties.

This invention relates to a copper alloy for connecting devices that has excellent practical properties such as fatigue properties.

[Conventional technology]

Cu alloys are often used in the parts and materials of electronic and electrical equipment, but in recent years there has been an emphasis on miniaturization, higher density, and higher precision, as well as economic efficiency, and traditional pure copper has been used.

In place of brass and phosphor bronze, there is now a demand for materials that have both higher performance and economic efficiency. For example, even though phosphor bronze has far better mechanical properties than brass, in addition to its stress relaxation properties and susceptibility to stress corrosion cracking (SCC), it is also difficult to join with solder alloys, which are common in connecting parts of electronic and electrical equipment. Reliability is a big problem.

A similar type of defect occurs when Sn or PB gold alloy solder plating is used instead of precious metals for electrical contacts and connections, and the adhesiveness is lost over time, resulting in a peeling phenomenon similar to the solder joints described above. This is a phenomenon caused by the diffusion reaction between Cu and Sn, and it progresses even at low temperatures below 100°C.
As exemplified in Japanese Patent Application Laid-open No. 41222 and Japanese Patent Application Laid-open No. 108562/1987, extra steps are required, such as forming a thick Cu or Ni barrier layer in advance by plating or the like.

For this reason, some Cu-Fe alloys, such as C194 (2
,3wt%Fe,Q,l2wt%Zn,θ,03
wt%P, W1% below the balance CuH is abbreviated as %) and C19
5 (1.5% Fe, 0.6% Sn, 0.2% Co, 0.
03% P, balance Cu), etc. are used. These alloys are made by precipitating and dispersing a large amount of Fe in the form of phosphorous compounds or elemental metals, and have a certain level of strength and conductivity, but in order to cope with the high performance of electronic and electrical equipment, The performance is insufficient, there are also problems in terms of magnetism, and there is also a problem that the reliability of the solder joint is poor.

[Problem to be solved by the invention]

Under these circumstances, copper alloys having the following properties are strongly desired in order to improve the performance of electronic and electrical equipment by increasing their size, density, and precision.

(1) In order to achieve smaller size and higher density, strength and conductivity, which have a contradictory relationship, should be balanced at a higher value.

(2) Good stress relaxation properties.

(3) Do not cause SCC.

(4) Solder joints and Sn, 5n-Pb alloy plating should not peel off over time.

(5) Less influence of magnetism.

(6) The composition must be advantageous for manufacturing without causing defects such as cracks during hot working.

[Means to solve the problem]

In view of this, the present invention was developed as a result of various studies.

Connecting devices for internal and external electrical equipment, especially IC socket connectors, outlet switches, relay contact springs, terminals, etc., with excellent practical properties such as strength, conductivity, plating properties, solderability, stress relaxation properties, fatigue properties, etc. This is a copper alloy developed for use in copper alloys.

That is, one of the copper alloys of the present invention contains 1.5 to 6.0% Ni, 5
i (1, including 1 to 3.0%, PO, +2 to 1.0%,
It is characterized in that the O2 content is 20 ppm or less, the S content is 10 ppn or less, and the balance consists of Cu and inevitable impurities.

Another copper alloy of the present invention has Ni1.5 to 6.0
%, Si0. I~3.0%, PO, 12~1.0%.

Contains 5.0% or less of Zn, and further contains 0.6% or less of Mg.

Mn 0.6% or less, Cr 0.35% or less, VQ, 1
% or less, Ti0J5 or less, Co0.6% or less, a total of 1. [Contains 1% or less,
It is characterized by having a 02 content of 20 ppm or less, an S content of 10 ppi or less, and the remainder consisting of Cu and inevitable impurities.

[For production]

The copper alloy of the present invention has a Ni content of 1.5 to 6.
0%, Si content 0.1-3.0%, P content 0.
12 to 1.0%, and these Ni, St,
By sympathizing with each other, P provides high strength, excellent conductivity, stress relaxation characteristics, and good spring characteristics. That is, these are Nj-Si compounds and Nj-
It forms a P compound or a (Ni, P)-3ia base compound, and exhibits the function of dramatically improving the above-mentioned properties.

However, if the content of each of Ni, Si, and P is below the lower limit, the effects due to these effects will be weak, and it will be difficult to obtain sufficient strength. Moreover, if the upper limit is exceeded, Ni and S will be affected by the empathy effect.
Each or some of the elements i and P are in excess, resulting in unbonded Ni.

This is because Si and P are present in the steel, significantly impairing hot workability, soldering properties, magnetism, electrical conductivity, etc.

Next, the 02 content was limited to 29 ppm or less.
This substance has a function of impairing plating adhesion and making the above compound coarser. Although it has good properties within this range, if it is contained beyond this range, the strength-improving effect of the compound is weakened and the plating adhesion becomes worse. This is because the properties are reduced, causing blistering and peeling, and deteriorating reliability. In addition, the S content is limited to IQppn or less because the content greatly contributes to hot workability, but if it is contained beyond this range, the hot working conditions, especially the hot working temperature range, will be significantly narrowed. This is because productivity is reduced and hot cracking is more likely to occur.

Furthermore, containing 5.0% or less of Zn is because Zn improves soldering properties, especially the bonding properties between the solder and the alloy base material, improves reliability, and improves migration resistance. However, if the content exceeds this range, although these effects are maintained, the conductivity will be impaired and the heat dissipation of heat generated during connection will become insufficient.

Also, Mg 0.6% or less, Mn 0.6% or less, Cr0
．． 35% or less, VO, 1% or less, Ti 0.35% or less.

The reason why one or more of Co 2 O is contained in a total amount of 1.0% or less within the range of 6% or less improves workability in the manufacturing process within the above range. Especially M
g and Mn contribute to improving solderability, hot workability and strength, while Cr and V.

Ti and CO significantly suppress the coarsening of crystal grains during heat treatment in the middle of the manufacturing process, thereby smoothing the surface texture during bending, preventing surface cracks, and improving bending workability. In addition, there is excess Ni and Si dissolved in the steel.

Forms a compound with P and increases conductivity. However, if these additive elements are contained in excess of their respective upper limits, they not only deteriorate castability and make it difficult to obtain a sound ingot, but also have an adverse effect on hot workability. This is also because it impairs the adhesion and conductivity of the plating.

Next, the alloy of the present invention can be produced by rapidly cooling after hot working, for example, after passing through water cooling treatment, and then repeatedly performing a combination of cold working and aging treatment, or by solution treatment in an intermediate process after hot working. After processing and solid solution of the constituent elements,
It is mainly manufactured by a manufacturing method that combines cold working and aging treatment to finely disperse and precipitate the above compounds to improve performance. Further, higher properties can be obtained by combining temper annealing at 200 to 550°C, tension leveler, tension leveler annealing in the temperature range of 400 to 850°C, etc. after the final cold working.

〔Example〕

The present invention will be described below with reference to Examples.

Example 1 A copper alloy having the composition shown in Table 1 was melted and cast in a charcoal coating,
Hot rolling was performed at 900° C., and immediately after that, it was immersed in water to cool it down. This was turned into a plate with a thickness of 8 m. This plate was repeatedly subjected to cold working and heat treatment at 520℃, resulting in a thickness of 0.
．． After forming a 5M plate, it was heated and held at a temperature of 850°C for 80 seconds, then rapidly cooled and subjected to solution treatment. After subjecting the surface to pickling and grinding, cold working was performed at a working rate of 40%, the plate was finished to a thickness of 0.3 mm, and temper annealed at a temperature of 400° C. for 1 hour to obtain a test material. Using this test material, mechanical properties, electrical conductivity, workability, heat-resistant solder peelability, stress corrosion cracking resistance, stress relaxation properties, and plating properties were investigated. The result is the second
Shown in the table.

Mechanical properties (tensile strength and elongation) are Tsuki S-7224+
+: The conductivity was measured based on JIS-Ho2O3. Bending workability is tested using the V-block method based on Its-X2248, and is calculated by dividing the minimum bending rate (R) that causes cracks on the surface of the test piece by the thickness (1) of the test piece (R/t). Indicated. Heat resistant solder removability is
After cutting out a strip with a width of 5 mm and soaking it in 60/40 solder using rosin-based flux,
After 700 hours of accelerated testing at a temperature of 0°C, 180
The sample was bent closely and the presence or absence of solder peeling was observed. Stress corrosion cracking resistance is according to Its-C8306, 3 vo1%
The cracking time was determined by the constant load method in NH and steam. The load was 50% of the tensile strength. The stress relaxation properties were determined by measuring the stress relaxation rate after conducting a test for 1000 hours in a constant temperature bath at 150°C, with the initial stress being 50% of the 0.2% proof stress.
Less than 10% is indicated by an O mark, and 10% or more is indicated by an X mark. The plating property was determined by plating Ag to a thickness of 5.0 μm using a cyanide bath, heating it at 450° C. for 10 minutes, performing a tape peeling test, and examining the presence or absence of peeling using a microscope.

Example 2 The hot rolled plate with a thickness of 8 mm in Example 1 had a thickness of 93.8 mm.
Cold working was performed at a processing rate of 0.5% to form a board with a thickness of 0.5 mm. This was heat treated at a temperature of 450℃ for 2 hours, and then cold worked at a processing rate of 40% to a thickness of 0.3+nm.
A test similar to that of Example 1 was conducted using a plate that had been subjected to temper annealing at a temperature of 400°C for 1 hour as a test material.
The results are shown in Table 3.

As is clear from Tables 1, 2, and 3, all of the alloys Nα1-13 of the present invention are uniformly superior in each property as compared to the conventional alloys Nα20-22.

On the other hand, comparative alloy N, which is outside the composition range of the alloy of the present invention,
It can be seen that one or more of the characteristics are inferior for α14 to α19. That is, comparative alloy 1!114, which has a small amount of Ni and P, does not provide satisfactory strength, while comparative alloy k15. which has a large content of Si or P. It can be seen that at +6, the conductivity is extremely low, and furthermore, the solder heat resistance and plating adhesion are greatly deteriorated. In addition, the strength and plating adhesion of the comparative alloy Nα18, which has a high O2 content, was impaired, and the subcomponent (Mg).

Comparative alloy Nα17 with a large amount of Mn, Cr, V, Ti, Co)
Comparative alloy NCL19 has poor castability and high S content.
However, severe cracking occurred during hot rolling, and test pieces could not be made.

〔Effect of the invention〕

As described above, according to the present invention, it has both excellent conductivity and strength, and at the same time has practical properties such as good bending workability, plating property, solderability, stress relaxation property, fatigue property, and corrosion resistance. Excellent for use in connection equipment for electronic and electrical equipment.
It has remarkable industrial effects, such as enabling miniaturization, higher density, and higher precision.

Claims (2)

[Claims] (1) Ni1.5-6.0wt%, Si0.1-3.0
A copper alloy for connecting devices, which contains 0.12 to 1.0 wt% of P0.12 to 1.0 wt%, an O_2 content of 20 ppm or less, a S content of 10 ppm or less, and the balance being Cu and inevitable impurities. (2) Ni1.5-6.0wt%, Si0.1-3.0
wt%, P0.12-1.0wt%, Zn5.0wt%
Contains the following, and further includes Mg0.6wt% or less, Mn0.6w
t% or less, Cr 0.35wt% or less, V 0.1wt% or less, Ti 0.35wt% or less, Co 0.6wt% or less, and contains any one or more of two or more types in the range of 1.0wt% or less in total, O_2 content The amount is 20 ppm or less, the S content is 1
Copper alloy for connecting devices consisting of 0 ppm or less, the balance being Cu and unavoidable impurities.