JPH05339797A - Soluble electrode of radial-cell electroplating device - Google Patents

Abstract

PURPOSE:To provide the soluble electrode of a radial-cell electroplating device capable of preventing a defective power supply due to the corrosion, etc., of the conductor surface in contact with an anode support. CONSTITUTION:This soluble electrode 3 is provided before and behind a conductor rotary drum 1 to introduce a metallic strip 2 into a plating soln. with a radial current-carrying gap in-between and supported by an anode support 5 freely movably in the axial direction of the drum, and a plate 11 consisting of a highly corrosion-resistant material such as carbon and titanium is fixed to one side face forming a conductor surface in contact with the support 5 to constitute the soluble electrode 3 of a radial-cell electroplating device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fusible electrode for a radial cell type electroplating apparatus, and more particularly to a novel fusible electrode useful for effectively preventing conduction failure of a current-carrying surface caused by corrosion by a plating solution. This is a proposal for the structure.

[0002]

2. Description of the Related Art In a radial cell type electroplating apparatus, a large-diameter current-carrying drum is immersed in about 1/2 of a plating solution, and a metal strip to be plated is rotated along the outer peripheral surface of the rotary drum. It is a device for plating by energizing the strip through a plating solution between the strip and a positive electrode (anode) installed at a radial energization gap while traveling in synchronization.

This device is suitable for plating only on one surface of the strip due to its constitution, and since the current-carrying gap is small, the resistance of the plating solution is small and the power consumption is small. Therefore, high-speed plating with a large current is possible. Is.

In general electroplating, there are a case where an insoluble electrode is used as an anode and a case where a metal to be plated is used as a soluble electrode. Of these, the latter is suitable for thick plating by applying a large current because it is easy to replenish the metal to be plated and does not generate gas on the electrode surface.

However, in this method, since the anode is consumed as the plating progresses, the current-carrying gap gradually increases as the plating progresses, and the resistance of the plating solution increases correspondingly to increase the power consumption or the current density. It has been pointed out that the amount becomes smaller and, as a result, the amount of plating adhered decreases. From this,
In the above electroplating using a soluble electrode, it was necessary to appropriately correct the fluctuation of the current-carrying gap depending on the wear of the anode.

Therefore, in the radial cell type plating using a soluble electrode, an anode support is provided almost parallel to the generatrix of the energizing rotary drum according to the degree of wear of a plurality of pairs of horizontally arranged arcuate anode pieces. The current-carrying gap is corrected by sequentially advancing in the plate width direction, and periodically performing attachment for replenishment and removal for discharge.

The anode support for supporting the soluble electrode has the necessary conditions for a plating apparatus of this kind, such as not being affected by a plating solution, having a small overvoltage and being inexpensive, as shown by reference numeral 5 in FIG. A rod having a rectangular cross section is suitable.

Conventionally, as an anode support which satisfies these conditions, a current-carrying surface (contact surface with the anode) that is heavily consumed.
It has been proposed to use a removable wear plate and replace the main body with graphite with a more conductive material to reduce the voltage drop and reduce unnecessary power consumption ( JP-A-58-151495,
(See JP-A-58-151496 and JP-A-58-151497).

[0009]

According to the method of the above-mentioned prior art for the anode support, sliding of the anode piece or the like does not cause wear of the current-carrying surface with which the anode piece comes into contact, so that the current-carrying gap can be prevented. Variations can be corrected accordingly.

However, with only such an improvement of the anode support, one side surface of the anode piece which is in contact with the anode support and forms a current-carrying surface is corroded by a plating solution such as zinc chloride, resulting in a small contact area. However, depending on the type of alloy plating, the generation of a current-carrying substance may cause a current-carrying defect, resulting in a problem that the uniform coating amount is impaired.

An object of the present invention is to solve the problems of the above-mentioned prior art, and particularly to effectively prevent defective conduction due to corrosion or the like on one side surface of an anode piece which forms a conductive surface in contact with the above-mentioned anode support. It is to provide a soluble electrode that can

[0012]

As a result of intensive studies to realize the above object, the inventor has arrived at the present invention having the following contents.

That is, according to the present invention, a rotating drum for energization that guides the passage of a metal strip into a plating solution is disposed in front of and behind in the sheet passing direction with an energization gap in the radial direction separated by an anode support. A radial cell-type electric device, which is a fusible electrode movably supported in a drum axial direction, wherein a plate made of a highly corrosion-resistant conductive material is attached to one side surface which is in contact with the anode support and forms a current-carrying surface. It is a soluble electrode of the plating apparatus.

[0014]

FIG. 1 is a diagram of a radial cell type electroplating apparatus using a soluble electrode according to a preferred embodiment of the present invention.
In the description of this drawing, reference numeral 1 shown in the drawing is a rotary drum for energization, and a metal strip 2 which is in contact with the outer peripheral surface of the rotary drum 1 and runs synchronously with the rotation is wound. The soluble electrodes 3 according to the present invention are respectively provided in front of and behind the passage bath immersion path which separates the current-carrying gap in the radial direction of the drum sandwiching the metal strip 2.

The fusible electrode 3 is composed of, for example, a plurality of pairs of anode pieces 3'having an arcuate shape along the outer periphery of the rotary drum 1 as shown in FIG. A locking projection 4 is provided on the side opposite to. Then, each of the anode pieces 3 ′ has a locking projection 4 provided on the back surface thereof movably hooked on a locking receiver of an anode support 5 so that a pole between the anode piece 3 ′ and the outer circumference of the rotary drum is movably fixed. It is held in the plating tank in an attitude that makes the distance (energization gap) uniform.

With respect to the soluble electrode 3 held in the plating bath in this way, in the present invention, in order to prevent conduction failure of the current-carrying surface caused by corrosion by the plating solution such as zinc chloride, the current-carrying surface in contact with the anode support is prevented. In addition, a plate made of a conductive material having excellent corrosion resistance such as carbon and titanium is attached.

As a method of attaching the plate, mechanical joining using a screw made of a material having excellent corrosion resistance such as carbon, titanium, and stainless steel is performed from the standpoint of electricity conduction between the anode support, the plate and the anode. desirable.

In the soluble electrode of the present invention having such a structure, a plate made of carbon, titanium or the like having excellent corrosion resistance and conductivity is attached to the current-carrying portion in contact with the anode support, so that the current-carrying portion is not corroded by the plating solution. It is possible to solve the problem of reduction of the contact area and the problem of reduction of the contact area, and to prevent the generation of the non-conductive substance in the current-carrying part.

As can be seen from this, in the radial cell type electroplating using the soluble electrode of the present invention, there is no conduction failure due to corrosion of the current-carrying surface.
A plated steel sheet with a uniform coating weight can be easily manufactured.

In the plating using the soluble electrode as in the present invention, the current-carrying gap G must be always maintained at an appropriate distance from the viewpoint of electrical efficiency.
As the plating progresses, the anode surface of the anode piece 3 ′ is gradually consumed and the energization gap G fluctuates in the direction of increasing, so that it is necessary to sequentially adjust the insertion of a new anode piece 3 ′.

Corresponding to this, in the plating apparatus according to the present invention, the anode supports 5 juxtaposed in the direction of the generatrix of the rotary drum in the tank are gradually narrowed in the lateral movement direction of the anode piece 3 '. And supports it, and advances each anode piece 3 '... along the anode support 5 according to the degree of consumption of the anode surface, and replenishes and uses a new anode piece 3 "according to the operation. The finished anode piece 3 '"is taken out to adjust the gap between the electrodes.

This adjustment between the electrodes is performed by the pusher 7 which is periodically operated to laterally move each anode piece 3 ', insert and attach the new anode piece 3 "to one end of the anode support 5, and use it from the other end. The anode piece 3 ', which is performed by removing and removing the completed anode piece 3'"and performing the above-described inter-electrode adjustment.
In order to prevent wear of the current-carrying surface 9 of the anode support 5 due to movement or the like, it is desirable to employ a removable wear plate so that at least that current-carrying surface can be easily replaced.

As such a wear plate, it is said that it is resistant to friction caused by sliding the anode piece 3'for adjusting the gap between electrodes, has good corrosion resistance to a plating solution such as zinc chloride, and has excellent conductivity. It is preferable to use titanium, niobium, tantalum, or zirconium as a material that satisfies the requirements.

[0024]

EXAMPLE An experiment for producing an alumina-dispersed hot-dip galvanized steel sheet was conducted using the soluble anode shown in FIG. 2 as the soluble electrode of the radial cell type electroplating apparatus shown in FIG.
As a comparative experiment, an experiment for producing an alumina-dispersed hot-dip galvanized steel sheet was performed using a conventional soluble anode made of pure Zn only. Table 1 shows the manufacturing conditions of these plated steel sheets.

[0025]

[Table 1]

In producing a plated steel sheet, the change in electric resistance between the electrode and the strip with the passage of plating time was measured. The result is shown in FIG. As is clear from the results shown in this figure, when the soluble electrode of the present invention is used,
It was found that there was almost no change in the inter-electrode resistance value even after continuous plating for 7 hours, and the value remained almost constant over 7 hours.

On the other hand, in the case of using the conventional soluble electrode, a large amount of electrically non-conducting substance (alumina main component) is deposited at the contact portion of the electrode with the anode support about 4 hours after the start of plating and the electrode is The resistance started to increase, and after 7 hours, current flow became impossible.

From the above results, it was confirmed that the soluble electrode of the present invention is effective in preventing defective conduction.

[0029]

As described above, according to the fusible electrode of the present invention, a plate made of carbon, titanium or the like having excellent corrosion resistance and conductivity is attached to one side surface which is in contact with the anode support and forms a current-carrying surface. Therefore, it is possible to effectively prevent the conduction failure of the current-carrying surface caused by the corrosion of the plating solution.

[Brief description of drawings]

FIG. 1 is a perspective view (a) and a schematic sectional view (b) of a radial cell type electroplating apparatus.

FIG. 2 is a perspective view showing an example of a soluble electrode of the present invention.

FIG. 3 is a diagram showing changes in electric resistance between an electrode and a strip with the lapse of plating time.

[Explanation of symbols]

 1 Energizing Rotating Drum 2 Metal Strip 3 Soluble Electrode 3'Anode Piece 3 "New Anode Piece 3 '" Used Anode Piece 4 Locking Protrusion 5 Anode Support 7 Pusher 9 Current-carrying Surface 10 Zinc Metal 11 Carbon Plate

Claims (1)

[Claims] 1. A rotary drum for energization that guides the passage of a metal strip into a plating solution, which is arranged in front of and behind in the passage direction with an energization gap in the radial direction, and is arranged in the drum axial direction by an anode support. A fusible electrode that is movably supported, wherein a plate made of a highly corrosion-resistant conductive material is attached to one side surface that forms a current-carrying surface in contact with the anode support. electrode.