JP2537001B2 - Spring wire having solderability and corrosion resistance, and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spring wire having a Cu-Ni alloy plating layer having solderability and corrosion resistance, and a method of manufacturing the wire.

[0002]

2. Description of the Related Art Copper-plated and gold-plated wires have excellent solderability, while zinc-nickel plating or zinc-chromate treatment has been used for corrosion resistance. There are applied wires and stainless steel wires. Further, as a typical prior art, there is a Cu-Ni alloy plated wire disclosed in JP-A-58-90316.

[0003]

The copper-plated wire is easily oxidized and discolors immediately, and in a highly corrosive atmosphere, patina is generated and the commercial value is rapidly reduced. on the other hand,
Gold-plated wires have high corrosion resistance and hold soldering for a long time, but gold itself is expensive and causes a cost increase. On the other hand, a galvanized wire or a wire plated with zinc and chromate is liable to cause white rust or has poor solderability. Ni-plated wires and stainless steel wires show high corrosion resistance in the air, but are weak against chloride ions, poor in salt water resistance, and poor in solderability.

On the other hand, Cu-disclosed by the above publication
The Ni alloy plated wire is intended to effectively utilize the characteristics of Cu and Ni.
-It is intended to be used as a lubricant for wire drawing and rolling of Ni alloys, and it is obvious that there is nothing to mention about the specific structure as well as the technical idea of improving corrosion resistance and solderability. Is.

There are the following two conventional methods for performing Cu-Ni plating. One of them is a method of performing Cu-Ni alloy plating by electroplating using a mixed bath of Cu and Ni. However, in this case, since the precipitation potentials of Cu and Ni are separated by about 0.6 V, a complexing agent is required for eutectoid as an alloy. So far, baths using various complexing agents have been announced, but none of them has a uniform coating composition because they are easily affected by current density and stirring. The second method is a method in which Cu is first plated, then Ni is plated, and then heat treatment is performed to diffuse Cu and Ni to form an alloy plating. However, with this method, if the wire is iron, steel, or stainless steel,
When heated to diffuse Cu and Ni, Cu instantly penetrates into the base material, and the base material becomes brittle, causing a disconnection generally referred to as "cutting", and a Cu-Ni alloy plated wire. I know I can't get it.

The present invention has been made to solve various problems in the conventional Cu-Ni alloy plating, and an object of the present invention is to provide a uniform coating composition and Salt water resistance, without causing embrittlement
Cu-Ni with excellent solderability and workability such as wire drawing
This alloy-plated spring wire is provided and this Cu-N
An object of the present invention is to propose a manufacturing method that is most suitable for manufacturing a wire for an i-alloy plated spring.

[0007]

SUMMARY OF THE INVENTION The present invention, however, has the following construction in order to achieve the above object. That is, according to the present invention, at least the uppermost layer and the lowermost layer are made of Ni.
A Cu-Ni alloy plating layer of the layer, and having a Cu and Ni multi-layer plating layer diffused, wherein the ratio of the thickness of the Ni layer to the total thickness of the plating layer is 5 to 80%. Cu-Ni with characteristic solderability and corrosion resistance
It is a wire for alloy-plated springs.

The present invention also provides a Cu and Ni multi-layer plating layer in which at least the uppermost layer and the lowermost layer are Ni layers, and
After performing the multi-layer plating in which the sum of the thicknesses of the Ni layers is adjusted to 5 to 80% of the total thickness, 500 to 1200
A method for producing a Cu-Ni alloy-plated spring wire having solderability and corrosion resistance, which is characterized in that Cu and Ni are diffused by heating at a temperature of ° C.

[0009]

According to the present invention, the wire surface is first plated with Ni, then with Cu, and then with Ni and Cu, if necessary, and finally with Ni, and then heated. The treatment makes it possible to diffuse Cu and Ni without Cu invading the base material and Cu- which has excellent adhesion.
It is possible to obtain a wire for Ni alloy plated spring. In this case, by adjusting the thickness of the Ni plating to be 5 to 80% of the total plating thickness, the plated layer after the heat treatment becomes a uniform Cu-Ni alloy plated layer by diffusion, which will be described later in detail. As is clear from the contents of the explanation, Cu- which is excellent in salt water resistance, solderability, and workability such as wire drawing.
A wire for a Ni alloy plated spring can be easily obtained.

The heat treatment can be carried out at a temperature of 500 to 1200 ° C., but in order to carry out the diffusion in a short time, 1050 ° C.
It is desirable to heat above. By the way, the top layer is C
In the case of u, when heated to 1050 ° C. or higher, Cu has a drawback that the surface becomes uneven due to a phenomenon in which Cu starts to melt and sags before interdiffusing with Ni. Such a phenomenon can be prevented by performing the Ni plating and forming the Ni plating layer as the uppermost layer.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in the enlarged cross section in FIG.
IS G3506 SWRH82B material or JIS
On the surface of the core wire 2 made of G4308 SUS304 material,
A three-layer plating 3 having a lower layer of Ni, an intermediate layer of Cu, and an upper layer of Ni is continuously plated with an electroplating facility having three plating baths to obtain a Cu-Ni alloy-plated spring wire 1. It was As a pretreatment for plating, 30% H ₂ SO ₄
Pickling, 15% Hcl pickling, Ni strike bath (nickel chloride 240g / l, Hcl (specific gravity 1.18) 125
ml / l).

The nickel bath is nickel sulfamate 4
50 g / l, boric acid 30 g / l, PH 4.0, temperature 50
C, current density ^{2 to} 10 A / dm ² , various conditions of Ni plate anode. Copper plating bath is copper sulfate 200g / l, sulfuric acid 50
g / l, normal temperature, current density ^{2 to} 20 A / dm2, various conditions of Cu plate anode. Plating composition is 1 for total plating thickness
0 μ, and the sum of the thicknesses of the lower and upper Ni plating layers is 1, 2, 5, 10, 20, 30, 4 with respect to the total plating thickness.
Plating was performed by adjusting the plating time and the current density so as to change to 0, 50, 60, 70, 80, 90% to obtain 12 kinds of alloy plated wires having different plating compositions.

These wires are heated in an argon atmosphere at 500 to
After heat treatment at 1200 ° C., corrosion resistance and solderability were investigated. The corrosion resistance was evaluated by the JIS Z2371 salt spray test. On the other hand, solderability is JIS C5
033 was immersed in a solder bath of 63% Sn-37% Pb and a temperature of 230 ° C., and then vertically pulled up, and the coating state was observed and evaluated.

The results of the salt spray test are shown in FIG. However, as a survey sample according to the present invention, 20
% Ni-80% Cu alloy plating, plating total thickness 10μ
The test result is shown by the line a. On the other hand, as a comparative material, the coating weight is 250 g / m ²
3 types of wire are used: zinc plated wire, Ni plated wire with a thickness of 3μ, and stainless steel SUS304 element wire.
The test results are shown in the lines B, C, and D, respectively. Cu-Ni alloy plated wire according to the present invention (see wire a)
No red rust was observed up to a spraying time of 1000 hours, and it was revealed that each of the comparative materials (see lines A, B, and C) was far superior in corrosion resistance.

Twelve kinds of alloy-plated spring wires 1 having different plating compositions obtained by the above-mentioned procedure were subjected to a salt spray test, and the rust degree (%) after 1000 hours of salt spray was examined. As shown in FIG. As is clear from this figure, it can be seen that those having a Ni ratio in the range of 5 to 80% have excellent corrosion resistance without rusting. In addition, about 5% or less, F of the substrate surface
It is considered that rust is likely to occur because e is often partially exposed due to the unevenness.

Next, the results of examining the solderability of the 12 types of alloy-plated spring wires 1 are shown in FIG. According to this figure, the Ni ratio is 80% or less.
It can be seen that the Cu alloy plating is good because it has solderability almost equivalent to that of the Cu plated wire.

As is clear from the above test results, at least the uppermost layer and the lowermost layer each have a Cu-Ni alloy plating layer, and the Ni layer has a total thickness of the plating layer before the diffusion treatment. Cu-Ni with a thickness ratio of 5-80%
It is clear that the alloy-plated spring wire is very excellent in corrosion resistance and solderability.

In the above embodiment, the case of three-layer plating was described, but the present invention is not limited to this, and as multi-layer plating such as 5 layers, 7 layers and 9 layers is achieved,
It is needless to say that a uniform alloy layer can be obtained rather quickly after the diffusion treatment, which is preferable.

[0019]

As described above, according to the present invention, the spring wire has a Cu-Ni alloy plating layer on the surface of which the ratio of the thickness of the Ni layer to the total thickness of the plating layer before the diffusion treatment is 5 to 80%. In addition to having high corrosion resistance, it also has excellent solderability, and has excellent wire drawing workability and rolling workability.

Further, according to the method of the present invention, first, the lowermost layer is plated with Ni, then the Cu is plated, and then the uppermost layer is plated with Ni, so that Cu may penetrate into the substrate during the heat treatment. In addition, the surface of the Cu-Ni alloy plated spring is smooth and has good adhesion after heating is completed. Further, in the conventional case where Cu-Ni alloy plating is performed in a mixed bath of Cu and Ni, the plating bath is unstable and a uniform film cannot be obtained.
Both plating and Cu plating can be performed with a plating bath that has been widely adopted from the past and is easy to manage, and therefore can be manufactured easily at low cost and with high accuracy.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a spring wire according to an embodiment of the present invention.

FIG. 2 is a rusting degree transition diagram of the spring wire of the present invention and the comparative wire.

FIG. 3 is a diagram showing the degree of rusting of various Cu—Ni alloy plated wires with different Ni thickness (%) after 1000 hours of salt spray.

FIG. 4 is a table of results of solderability investigation of various Cu—Ni alloy plated wires with different Ni thickness (%) and wires with different plating.

[Explanation of symbols]

 1 ... Cu-Ni alloy plated spring wire, 2 ... Core wire, 3 ... 3-layer plating.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Yamaoka 10-1 Nakahama-cho, Amagasaki City Shinko Steel Wire Industrial Co., Ltd. (56) References JP-A-3-79790 (JP, A) JP-A-3- 104883 (JP, A) JP-A-3-170693 (JP, A) JP-A-5-320842 (JP, A) JP-A-58-90316 (JP, A)

Claims (2)

(57) [Claims] 1. At least the uppermost layer and the lowermost layer are Ni layers of C.
It is a u-Ni alloy plated layer, and has a multilayered Cu and Ni plated layer having a ratio of the thickness of the Ni layer to the total thickness of the plated layer of 5 to 80% by diffusion treatment. A Cu-Ni alloy plated spring wire with solderability and corrosion resistance. 2. A multilayer plating layer of Cu and Ni in which at least the uppermost layer and the lowermost layer are Ni layers, and the total thickness of the Ni layers is adjusted to be 5 to 80% of the total thickness. Of Cu-Ni alloy-plated spring wire having solderability and corrosion resistance, which is characterized by performing Cu / Ni diffusion treatment by heating at a temperature of 500 to 1200 ° C. Production method.