JPH11315394A - Plating treating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an Ni plating layer having high ductility and high toughness, excellent in adhesion and whose peeling is prevented at the time of working by dipping a metallic base into an Ni plating bath and applying it with electroplating at current density in a specified range. SOLUTION: The current density is regulated to <=100 A/dm<2> . Preferably, the hardness of the Ni plating layer is regulated to <=450 Hv. The metallic base is composed of stainless steel, the metallic base is composed of stainless steel wire, and, on the surface of the Ni plating layer, a Cu plating layer is moreover formed to form into the stainless steel wire with the plating. As the current density at the time of the Ni plating is increased, the Ni plating layer to be formed is made hard, and the crystal grains of the Ni plating layer are made coarse, so that the Ni plating layer is made easy to be peeled when working the Ni plating article. In the execution of the Ni plating at the current density of <=100 A/dm<2> , the hardness of the Ni plating layer is reduced to secure good ductility, the crystal grains are moreover refined to increase the adhesion with the metallic base, and the peeling of the Ni plating layer is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating method, and more particularly to a method characterized by a method of forming a Ni plating layer.

[0002]

2. Description of the Related Art
For the steel wire for welding, Cu plating is performed to prevent rust, secure electrical conductivity, and the like. By the way, in the case of non-stainless steel wire for welding,
Although it is possible to apply Cu plating directly on the surface of the steel wire substrate, in the case of stainless steel wire, there is a passivation film on the surface, and there is a problem that the passivation film inhibits Cu plating, Therefore, in the case of such a stainless steel wire, first, N
An i-plate layer is formed, and thereafter, the surface of the Ni-plate layer is further plated with Cu.

[0003] Since Ni plating is performed in an acidic bath, the passivation film on the surface of the stainless steel wire base is eluted at that time, and therefore, it is necessary to form the Ni plating layer in such a manner as to replace the passivation film. You can.

In manufacturing a stainless steel wire for welding, wire drawing is usually performed to obtain a desired thickness. However, in the conventional wire drawing process, the Ni plating layer is peeled off from the stainless steel wire base. Had a problem that Although the above description has been made by taking the welding wire as an example, this problem can occur commonly when a Ni plating layer is formed on the surface of a metal substrate.

[0005]

The invention of the present application has been made to solve such a problem. According to the plating method of the first aspect, the metal substrate is immersed in a Ni plating bath to perform electroplating, and when forming a Ni plating layer on the surface of the metal substrate, the current density is set to 100 A / dm ² or less. It is characterized by doing.

A plating method according to a second aspect is characterized in that, in the first aspect, the hardness of the Ni plating layer is set to a hardness of 450 Hv or less.

According to a third aspect of the present invention, there is provided a plating method comprising:
2. The method according to any one of 2), wherein the metal base is stainless steel.

[0008] The plating method according to claim 4 is based on claim 1.
2. In any one of the aspects 2, the metal substrate is a stainless steel wire, and a Cu plating layer is further formed on the surface of the Ni plating layer to form a plated stainless steel wire.

[0009]

In order to solve the problem of peeling of the Ni plating layer, the present inventors paid attention to the current density at the time of Ni plating, and investigated the relationship between the current density and the peeling property.
As a result, as the current density at the time of Ni plating is increased, the hardness of the formed Ni plating layer becomes harder, and the crystal grains of the Ni plating layer become coarser. The Ni plating layer is likely to be peeled off during processing of the product, and the hardness of the Ni plating layer can be reduced when Ni plating is performed at a current density of 100 A / dm ² or less, and good ductility is secured. In addition, it has been found that the crystal grains can be refined, the adhesion to the metal substrate can be enhanced, and the peeling of the Ni plating layer during processing can be favorably prevented.

The invention of the present application has been made based on such findings. That is, by performing the Ni plating treatment according to the present invention, the surface of the metal substrate can be made of N
An i-plated layer can be formed, and the Ni-plated layer can be made to have high adhesion to the surface of the metal substrate, so that peeling of the Ni-plated layer during subsequent processing can be prevented well.

In the present invention, the current density is 100 A /
dm ² or less (claim 1), and desirably 70 A / dm ² or less. On the other hand, in order to efficiently form the Ni plating layer, it is desirable that the current density be higher than 30 A / dm ² .

In the present invention, it is desirable that the hardness of the Ni plating layer is not more than 450 Hv. Furthermore, the present invention is particularly suitable as a method for forming a Ni plating layer on the surface of stainless steel as a metal substrate (claim 3). In particular, the invention of the present application can be suitably used for producing a plated stainless steel wire having a stainless steel wire as a metal substrate, a Ni plating layer formed on the surface thereof, and a Cu plating layer formed on the surface. (Claim 4).

[0013]

Next, embodiments of the present invention will be described in detail. Table 1
Stainless steel wire base for welding with the chemical composition shown in (φ
2.7 mm, 255 Hv) was changed to Ni having the following composition.
The plate was immersed in a plating bath and subjected to plating at various temperatures and various current densities under conditions of normal temperature and plating time of 10 minutes.

[0014]

[Table 1]

<Ni plating bath composition> HCl 20-35% Ni 100-150 g / l

The hardness of the obtained Ni plating layer (measurement of Vickers hardness) and the microstructure of the Ni plating layer were observed to determine the crystal grain size. The results are as shown in FIG. In addition, when a peeling test of the Ni plating layer was performed, the results shown in Table 2 were obtained.

[0017]

[Table 2]

The plating peel test was performed as follows. That is, a wire obtained by Ni plating (normal temperature, plating time: 4 seconds) around a wire of φ2.7 mm was wound using pliers (self-diameter winding), and the state of peeling of the Ni plating on the surface was observed using a 10-fold loupe.

As can be seen from these results, as the current density is increased in applying Ni plating, the hardness of the Ni plating layer becomes harder,
When the hardness exceeds A / dm ² , the hardness rapidly increases, the crystal grains become coarser, and the Ni plating layer which is good for the peeling of the plating is formed at a current density of 100 A / dm ^2. It can be seen that the condition is dm ² or less.

Here, the reason why the peeling of the plating easily occurs due to the hardening of the Ni plating layer is due to the decrease in the ductility of the Ni plating layer. This is due to the fact that the gaps between the grains are large under the small crystal grains, so that the adhesion between the Ni plating layer and the surface of the wire substrate is reduced.

If the current density is less than 30 A / dm ² , plating cannot be performed sufficiently well. Therefore, the current density is 3
Desirably, it is larger than 0 A / dm ² . Also, from the results in FIG. 1, the current density is 100 A / dm ² or less, especially
/ Dm ² and good results have been obtained in the following, therefore in the present invention needs to be a current density 100A / dm ² or less, desirably is 70A / dm ² or less.

The Ni plating on the surface of the stainless steel wire has been described in detail above.
It is provided as a plated stainless steel wire after Cu plating is applied to the surface of the i-plated layer.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention is applicable not only to the Ni plating of the stainless steel wire for welding of the above embodiment, but also to other stainless steel and other metal base surfaces. The present invention can be embodied in variously modified forms without departing from the gist of the present invention, for example, when the present invention is applied to Ni plating.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a current density and a Ni plating layer hardness and a relationship between a current density and a plating crystal grain size during a Ni plating process obtained in an example of the present invention.

Claims (4)

[Claims] 1. A plating method wherein a metal base is immersed in a Ni plating bath for electroplating, and a current density is set to 100 A / dm ² or less when forming a Ni plating layer on the surface of the metal base. Processing method. 2. The plating method according to claim 1, wherein said Ni plating layer has a hardness of 450 Hv or less. 3. The plating method according to claim 1, wherein the metal substrate is stainless steel. 4. The stainless steel wire according to claim 1, wherein the metal substrate is a stainless steel wire, and a Cu plating layer is further formed on the surface of the Ni plating layer to form a plated stainless steel wire. Characteristic plating method.