JPS60131992A - Method and device for continuous type alloy electroplating - Google Patents

Abstract

PURPOSE:To accomplish continuously alloy electroplating with stable quality by providing a specific section as a non-conducting region in the position where the electrolytes gushing from nozzles provided to insoluble electrodes disposed to face each other on both sides of a traveling strip collide against each other and subjecting the strip to alloy plating. CONSTITUTION:Cushion pad nozzles 4 are disposed in the position where insoluble anodes 2 disposed to face each other on both sides of a traveling strip 1 face each other. The part S of the surface on the anode side facing the strip and existing between the positions T and T apart by at least the distance corresponding to the inter-pole distance (h) in mutually outward directions from each of the positions A, A where the jets from a pair of the slits 3, 3 of the nozzles 4 collide against each other is provided as a nonconducting region then the strip is subjected to alloy plating. The plating deposition itself under the excessive plating liquid flow near the positions A, A is consequently prevented and the alloy plating film having the good performance is obtd. without the adverse influence of such plating deposition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plating method and apparatus that can continuously obtain alloy electroplated steel sheets of stable quality.

Recently, Zn has been used in fields such as automobiles, home appliances, and construction.
- Various alloy electroplated steel sheets, including Fe-based and Zn-Ni threads, have suddenly attracted attention due to their excellent properties such as corrosion resistance, paintability, workability, and weldability. Practical application is progressing at a rapid pace.

However, such alloy electroplated steel sheets originally have the following problems in terms of manufacturing.

1) Especially in recent years, due to the trend of rising construction costs of electroplating equipment, the total plating length of plating tanks [(number of plating tanks) x (
There is a movement to shorten the effective plating length/1 layer) as much as possible. Under these circumstances, there has recently been a tendency to use so-called high current density operations, in which the plating current density is increased and plating operations are performed at high current densities. This tends to result in a plating film that is smooth and has good adhesion. This is because when the current density becomes high, the deposition of plating metal on the strip to be plated becomes faster, and if the replenishment of plating metal near the surface of the strip, that is, diffusion movement, cannot keep up with this precipitation, a situation tends to occur. There is no other way than that. This tendency is observed not only in alloy plating but also in plating of simple metals such as Zn. A possible solution to this problem is to actively cause the plating solution to flow between the electrodes, between the lip and the anode, by, for example, blowing the plating solution. However, in the case of single metal plating, it is enough to make the flow of the plating solution between the electrodes thicker, but when it comes to alloy plating, it is not enough just to have a large flow; There is something. This is because the flow condition of the plating solution is related to the plating film composition and the form of the precipitated phase.
n-Ni type (Ni 5-20 wt%) or Zn
- In the case of Zn alloy (intermetallic compound) plating such as Fe-based (Fe 10~dQwt), if this flow becomes small, the powdering resistance (workability) of the plating film will deteriorate before the appearance of burnt plating. This is a problem, and conversely, if it becomes too large, the presence of the η phase in the plating film will lead to deterioration of corrosion resistance and weldability. That is, with regard to alloy plating, even if the plating solution is made to flow actively, there is a difficulty in stably maintaining the flow in an appropriate state.

11) In addition, in such high current density operation, when a soluble anode is used, the anode wears out quickly and requires frequent replacement and replenishment of the anode, which reduces operational downtime, replacement personnel, and man-hours. This results in a decrease in productivity and an increase in labor costs, and in the case of alloy plating, it becomes even more difficult to control the composition of the plating bath. Therefore, in high current density operation of alloy plating, the mainstream is the use of insoluble anodes.

However, when operating at high current density using an insoluble anode, a large amount of oxygen gas is generated on the anode surface and hydrogen gas is generated on the cathode (strip) surface, and it is difficult to remove these gas bubbles from between the electrodes. becomes a problem.

The accumulation of gas bubbles between the electrodes not only increases the plating voltage but also causes uneven adhesion and compositional changes in the plating film, so the gas bubbles generated between the electrodes must be removed as soon as possible. It is something that cannot happen.

FN) - Furthermore, in high current density operation, the amount of power consumption becomes a problem. The inter-electrode distance, that is, the distance (h) between the anode surface and the strip surface, is normally set to about 25 to 75 degrees, but if this can be reduced, power consumption can be saved. Power consumption in plating operations is largely dependent on the resistance of the plating solution filling the gap between the electrodes, and therefore it can be effectively reduced by shortening the distance between the electrodes. However, in reality, the vibration of the threading strip,
Due to poor shape (+-+1, !l1l), catenary, etc., the distance between the electrodes (h) must be about 25 trn to prevent short circuits due to contact between the strip and the anode, which is consumed by normal plating methods. Therefore, no reduction in power consumption can be expected.

As described above, it can be understood that there are various problems in the production of alloy electroplated steel sheets, and it is absolutely necessary to solve these problems, considering the recent growth in demand for alloy electroplated steel sheets. .

Many proposals have been made in the past regarding electroplating methods or apparatus intended for high current density operation. There are a wide variety of methods, but one that should be noted is the so-called cushion pad method, which applies static pressure to the strip that is passed through.

The basic idea is, for example, as shown in Figure 1 ((a) is a longitudinal side view, (b) is a partial perspective view)
A continuous slit nozzle hole (3) is provided on each front surface (25 (2') of the (insoluble) electrode of (2) (2) facing both sides of the electrode surface, and the electrolytic Plating is performed while jetting the liquid toward the strip surface, and the part of the strip surface surrounded by the jet impact position (■) from the slit nozzle hole (3) is
I) is a method that generates static pressure. The advantage of this method is that the systrip is supported from both sides by the action of the generated static pressure, so it is easy to prevent vibration of the strip, and to correct defects in the shape of the strip and catenaries (in the case of horizontal paths). Therefore, it is possible to realize so-called proximity electrolysis, in which the strip (1) and the anode (2) are brought close to each other for electrolytic treatment.

However, with this method, the flow of the interelectrode plating solution is inevitably weak in the static pressure generating part of the strip, and as a result, gas bubbles generated in that part tend to remain. Resistance becomes non-uniform depending on the position between the electrodes, causing variations in current density, resulting in an increase in plating voltage and, in the case of alloy plating, non-uniformity in the composition of the plating film and the precipitated phase. In addition, the plating solution flows strongly in the other inter-electrode parts compared to the above static pressure generating part, and in particular,
In the vicinity of the collision position of the nozzle jet surrounding the static pressure generation part, the plating liquid flows in the so-called Impinging Jet flow or W
The plating solution should not form an allet flow and exhibit an extremely strong flow state, and such variations in the flow state of the plating solution depending on the position between the electrodes also lead to non-uniformity of the composition of the plating film and the precipitated phase. This is a major cause.

In addition, the method shown in FIG. 1 has disadvantages in terms of repair. That is, in general, when plating steel plates, etc., insoluble anodes include pb gold alloys such as Ag, Sn, Sb, and TA.

However, when such an alloy-based insoluble anode is used in an acidic plating solution, its lifespan is about six months to one year at most, and therefore requires periodic repair. It is. In addition, the strip may break inside the cell and the anode may be damaged, or the nozzle hole (3
) Due to the plating solution flowing at high speed inside the nozzle, the blowout width of the nozzle hole may become uneven due to so-called erosion corrosion, and the balance of static pressure acting on both sides of the systrip may be disrupted. Apart from this, repairs based on these issues will also become necessary. If the nozzle hole is directly provided on the electrode surface of the anode, it is not possible to perform partial repairs such as replacing only the nozzle part or the anode body, which increases the cost.The O-cushion pad method The basic one is shown in Fig. 1 above, but other advanced types are also known. That is, as shown in FIG. 2, a plating liquid ejecting nozzle (hereinafter referred to as a cushion pad nozzle) that applies static pressure to the strip surface, which is separate from the anode (2), is placed near the center of the anode (2) in the strip running direction. 5) (4) is installed and plated, and although this method has no disadvantages in terms of repair compared to the above-mentioned method, the flow of the plating liquid near the impact point of the nozzle jet is extremely tight. The result is the same as in the case shown in Fig. 1. Therefore, it is desirable that the alloy plating film has a stable and uniform composition and precipitated phase, and this method is also satisfactory for producing alloy plated steel sheets. It's not possible.

The present invention utilizes the inherent advantage of the cushion pad method in that proximity electrolysis is possible. It is intended for the purpose of providing.

That is, in the method of the present invention, for example, as shown in FIG. 3, cushion pad nozzles (
4), and as shown in FIG. 4, the jet impingement positions (8) (5) (
Here, the jet impingement position refers to the position (line) where a line (plane) extending from the center of the slit hole (3) intersects with the strip plane. ) are spaced apart from each other in the outward direction by a distance corresponding to at least the distance between the poles (h) (T) (
T) In the so-called cushion pad method, in which alloy plating is performed with the opposing surface (S) of the anode side strip in between as a non-current area, a jet of plating liquid from a nozzle on the anode side collides with the strip surface. Position (5
) If the flow of the plating solution is excessively large, this will lead to a decrease in the performance of the plating film in the case of alloy plating.

However, as a result of several experiments by the present inventors, (T)
- (8) While maintaining the arrangement where the distance between electrodes ≧ distance between electrodes (h) is maintained, if the anode side strip opposing surface portion (S) located between the positions (T) and (T) is made into a non-energized band, the above It has been revealed that plating precipitation itself does not occur under excessive flow of plating solution near the jet impingement location, its adverse effects are eliminated, and an alloy plating film with stable and good performance can be obtained.

In the present invention, the area of the anode-side Nutrip facing surface portion that is a non-current area is limited for the following reasons. In other words, the flow of the plating solution near the nozzle jet collision position is the so-called Impinging Jet flow or WallJet flow.
It exhibits an extremely large flow and has an adverse effect on alloy plating deposition due to its excessive mass transfer properties. Specifically, in the case of Zn-Ni or Zn-Fe alloy plating, for example, η phase will precipitate and the corrosion resistance of the plating film will deteriorate; In order to completely eliminate the influence of flow on the alloy plating film performance, in relation to the distance between poles #I (h), the anode side strip facing surface portion (S) between CI') and (T) is de-energized. It is necessary to make it an area.

Note that in the cushion pad method, the nozzle/pad
The gas bubbles generated in the static pressure generating part (I) due to l/(4) tend to accumulate because the flow of the plating solution in that part is weak, but in the method of the present invention, the gas bubbles generated in the static pressure generating part (I) are Since electricity is not applied during the process, the accumulation of gas bubbles does not affect the operation itself, and the problems associated with plating voltage and other problems are eliminated. It can be said that the method has great advantages in this respect as well.

Next, the present invention also provides an apparatus for carrying out the above-described alloy plating method.

The device of the invention can be used, for example, by replacing the required mutually corresponding parts of the electrode surfaces (2'l (j)) of the insoluble anodes (2) (2) of the rows and/or by replacing them as shown in FIG. 3 above. A cushion pad nozzle (4) made of an electrically insulating material is provided adjacent to the end (5) of the electrode surface (21 in the running direction of the Nutrip). Jet flow collision position (5) and its corresponding nozzle front end (6) bordering the nozzle hole side electrode surface (21)
The distance (411) from the position (T) on the strip surface corresponding to , that is, the position where the normal line (plane) intersects from the nozzle front end (6) to the strip surface, is the interelectrode distance ( h
) or more. In short, the cushion pad nozzle zL/(4) on the anode side is formed of an electrically insulating material, and the strip facing surface (4) of the nozzle is used to connect the anode side strike between (T) and (T). Facing part (
S) is configured as a non-energized band. That is,
The distance (7+) between (8) and (T) above is the distance between poles (h)
The reason for this is to ensure a non-energized band necessary for implementing the method of the present invention.

Hereinafter, the apparatus of the present invention will be explained in detail using specific examples.

First, in the apparatus of the present invention, it is essential to use a cushion pad nozzle, and FIGS. 5(a) to 5(e) show specific examples of this nozzle itself. In other words, (a) is a pair of slit holes (3) (3) along the slope direction.
The ejection directions (,) (a) of the strips (1) are parallel to each other and
) is in principle perpendicular to the (with pleasure(/→
Both show examples in which the jetting direction values) (a) are inclined inwardly with respect to each other. The one shown in FIG. 4 above is also of this type. In each case, the plating solution is supplied through a ladder (7) behind the slit holes (3) (3). On each side, the positions (5) and (T) and the distance <1) between these prisoners (T) are as shown in the figure, and the device of the present invention can maintain this distance <1>. The distance between poles (h) or more is set. Note that all the figures illustrate the case where the nozzle/V (4) is provided to replace a part of the electrode surface (2), but in the device of the present invention, the nozzle is also provided at the end of the electrode surface in the 7-trip traveling direction. (5) (See Figure 3) It is also possible to install it adjacent to the
Needless to say, it is sufficient to satisfy the condition 4>h only on the side bordering the electrode surface.

According to the original concept of mini, cushion pad nozzle, and so, it can be said that the slit hole should be continuous in a circular shape as shown in Figure 1, but in actual plating equipment, it is usually On both sides of the width direction, so-called edge masking for current control or the side wall of the mesh cell itself approaches, and there is originally little liquid flow in that direction, so the pair of slit holes (3 )(3) is necessary, but the slit hole in the direction connecting both slit holes is not necessarily necessary. Depending on the type of Metxel, etc., the installation or non-installation may be determined as appropriate.

The above-mentioned cushion pad nozzle structure based on the present invention can be applied to any type of plating equipment in which plating is performed using an anode placed against the strip while holding the strip in a space and passing the strip through the strip. It is something. Some examples of application of the structure of the present invention are shown here. That is, FIG. 6 shows an example of application to a plating apparatus having a horizontal type plating tank, in which a cushion pad nozzle /L/( 4).The one shown in Figure 3 above is also of this type, with a nozzle/
This is an example in which L/(4) is provided. FIG. 7 shows an example of application to a plating apparatus in the form of a vertical plating tank, in which (A) shows an insoluble anode (21 (2) disposed in a down path (Xl) and an up path (X2) in the strip running direction 2. In addition, the (mouth) is also the center and the end of the strip running direction of the electrode surface (
5) is provided with a cushion pad nozzle (4). Note that (a) in the same figure shows a so-called immersion type plating apparatus in which the entire anode (2) is immersed in the plating bath (8), but in (b), the anode (2) is not immersed in the plating bath;
This is an example of a so-called non-immersion type plating apparatus that performs plating by filling the gap (M) between the electrodes with the plating solution by spraying and supplying the plating solution from the cushion pad nozzle/I/(4).

The device structure of the present invention can thus be effectively applied to both immersion type and non-immersion type.

Next, the effects of implementing the present invention will be described using actual examples.

[Example 1] Using a cold-rolled steel plate coil with a plate thickness of 0, j+m, and Sakaide 250+1111, a horizontal plating bath system as shown in FIG. 3, equipped with a cushion nozzle (rad nozzle (4)) as shown in FIG. Zn-Ni alloy plating was performed in a plating device.At this time, the cushion pad nozzle /L/ (4) was
The plating solution is spouted so as not to generate catenaries at the center of the strip between the anodes (the center in the strip running direction), and the distance between the electrodes (h) and the distance between A and T (
/1) was plated with various changes.

The conditions for electrolysis are as follows.

Plating bath: (Ni2+)/[Zn''') concentration molar ratio 2
0-3O9 Bath temperature 50-65°C9 Bath pH 1.5-25 Current density: 40-120 A/dJ Line speed = 20-200 m/min Each plated steel plate obtained (Plating composition: Ni 5-20 wt% , matt adhesion amount: 20 f/rn' per side,
Corrosion resistance was evaluated by examining the time until red rust appeared using a salt spray test.

The results are shown in FIG. In the figure, ○: Good corrosion resistance (red rust generation time 120 hours or more), O: Same poor (red rust generation time 12 hours or more)
(less than 0 hours).

From the test results in the same figure, it can be seen that no matter what distance (h) between poles is taken, if the distance between TAs (A) satisfies the condition of E'''2h, an alloy plating film with good corrosion resistance can be obtained. .

[Example 2] Using a cold-rolled steel coil with a plate thickness of 0.41+II+11 and a plate width of 200 mm as a plating bath, [Fe”]/[Zn2
Town concentration molar ratio 10-25. Bath temperature 50-60' CI bath p
Plating was carried out in exactly the same manner as in Example 1 above except that a Zn-Fe bath of H1.5 to 2.0 was used, and the resulting Zn-Fe alloy plated steel plate was coated as follows. Corrosion resistance tests were conducted to evaluate performance.

<Post-painting corrosion resistance test> A plated steel plate is subjected to phosphate-based chemical conversion treatment, then electrocoated for automobile bodies (coating film thickness: 20 μm), cross-cuts are made in the coating film, and salt water spraying is carried out for 500 hours. Examine the corrosion status of the cross cut section by testing.

Figure 9 shows the test results. In the same figure, ○: Good corrosion resistance after painting (blister width under paint film 1.0111+++ or less);
・: Indicates the same defect (blister width under the coating film exceeds 1.0 mm).

The test results in the same figure also reveal that for any distance between poles <1), an alloy plating film with good corrosion resistance can be obtained as long as the distance between TAs (1) is 4>h. .

As is clear from the above description, the present invention makes it possible to continuously manufacture stable, high-performance alloy electroplated steel sheets using a cushion pad method that realizes close-in electrolysis that is effective in reducing power consumption. Therefore, it greatly contributes to improving the quality of various alloy-plated steel sheets and reducing manufacturing costs.

Applicant: Sumitomo Metal Industries, Ltd. Applicant: Mitsubishi Heavy Industries, Ltd. Fig. 1 Fig. 3 Fig. 2 Fig. 4 Fig. 8 Fig. 8 Single pole distance h (mm) Fig. 9 a J%'l iM-@ih (mm) Continued from page 1 0 Inventor Ken Yanagi - @ Inventor Yama 1) Katsuhiko @ Inventor Mitsuo Kato @ Inventor Original plate Tei Nibu 4-6-n Kannon Shinmachi, Nishi-ku, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Shipbuilding Internal procedure amendment, official document (method) % formula % 2. Name of the invention Continuous alloy electroplating method and apparatus 3. Relationship with the person making the amendment Patent applicant address 5-15 Kitahama, Higashi-ku, Osaka Name Name (21
1) Norifumi Kumagai, Representative of Sumitomo Metal Industries, Ltd. (
and 1 other person] 4. Agent 5, date i of amendment order 4.2B 6. Specification subject to amendment (full text) 7. Attachment with contents of amendment).

), Description 1, Name of the invention, Continuous alloy electroplating method and apparatus 2, Claims (1) In a method of continuously performing alloy electroplating while a strip is running, opposing arrangements are made on both sides of the running strip. A nozzle having a pair of slit nozzle holes along the width direction of the strip is disposed at the corresponding position of the pair of insoluble anodes, and static pressure is exerted on both sides of the systrip by ejecting the electrolyte from the nozzle. At the same time, the positions (T) (
T) An alloy electroplating method characterized in that alloy plating is performed with the opposing surface of the anode side strip located between as a non-current area.

(2) An apparatus that performs alloy electroplating continuously while a strip is running, in which the required corresponding portions of the electrode surfaces of a pair of insoluble anodes placed oppositely on both sides of the running strip are replaced, and/or An electrolytic solution jet nozzle /l/(4) made of an electrically insulating material is provided adjacent to the end of the electrode surface in the strip running direction, and this nozzle extends along the strip width direction to apply static pressure to the strip. A nozzle front end that has a pair of slit nozzle holes (3) (3) and that borders the jet impingement position M (5) from each nozzle hole and the electric surface (2) on the corresponding nozzle hole side. A continuous alloy electroplating device characterized in that a distance <1> from a position (1) on a strip surface corresponding to the distance <1> is greater than or equal to an inter-electrode distance (h).

3. Detailed Description of the Invention The present invention relates to a plating method and apparatus that can continuously obtain alloy electroplated steel sheets of stable quality.

Recently, Zn has been used in fields such as automobiles, home appliances, and building materials.
- Various alloy electroplated steel sheets, including Fe-based and Zn-Ni 'flb, have suddenly attracted attention due to their excellent properties such as corrosion resistance, paintability, workability, and weldability. Its practical application is progressing at a rapid pace.

However, such alloy electroplated steel sheets originally have the following problems in terms of manufacturing.

1) Especially in recent years, due to the trend of rising construction costs of electroplating equipment, the total plating length of plating tanks [(number of plating tanks) x (
There is a movement to minimize the effective plating length/1 tank). Under these circumstances, there has recently been a tendency to use so-called high current density operations, in which the plating current density is increased and plating operations are performed at high current densities. If the plating film becomes powdery or powdery (commonly called burnt or burnt), it tends to be difficult to obtain a smooth plating film with good adhesion. This is because when the current density becomes high, the plating metal is deposited far away from the strip to be plated, and the replenishment of the plating metal near the strip surface and the diffusion movement of the plated metal tend to be unable to keep up with this precipitation. There is no other way than that. This tendency is observed not only in alloy plating but also in plating of simple metals such as Zn. A possible solution to this problem is to actively flow the plating solution between the electrodes, between the lip and the anode, by, for example, blowing the plating solution. However, in the case of single metal plating, it is sufficient to make the flow of the plating solution between the electrodes thicker, but when it comes to alloy plating, it is not enough just to have a large flow, and proper conditions must be met. There is such a thing. This is because the flow condition of the plating solution is related to the plating film composition and the form of the precipitated phase.
n-Ni type (Ni 5-20 wtl) or Zn-F
In the case of Zn alloy (intermetallic compound) plating such as e-based (Fs 10 to 40 wt%), when this flow becomes small, the powdering resistance (workability) of the plating film deteriorates before the appearance of burnt plating. This is a problem, and conversely, if it is too large, the presence of the η phase in the plating film will lead to deterioration of corrosion resistance and weldability. That is, with regard to alloy plating, even if the plating solution is made to flow actively, there is a difficulty in stably maintaining the flow in an appropriate state.

i) In addition, in such high current density operations, when a soluble anode is used, the anode wears out quickly and requires frequent replacement and replenishment of the anode, which reduces downtime, replacement personnel, and This increases the number of man-hours, resulting in a decrease in productivity and an increase in labor costs, and in the case of alloy plating, it becomes even more difficult to control the composition of the plating bath. Therefore, in high current density operations of alloy plating, the mainstream is the use of insoluble anodes.

However, when operating at high current density using an insoluble anode, it is difficult to remove gas bubbles from between the cooking electrodes, where large amounts of oxygen gas are generated on the anode surface and hydrogen gas is generated on the cathode (strip) surface. It becomes a problem.

The accumulation of gas bubbles between the electrodes not only increases the plating voltage but also causes uneven adhesion and compositional changes in the plating film, so the gas bubbles generated between the electrodes must be removed as soon as possible. It is something that cannot happen.

1) Furthermore, in high current density operation, large power consumption becomes a problem. The distance between the electrodes, that is, the distance (h) between the anode surface and the strip surface, is normally set to about 25 to 75 cm, but if this can be reduced, power consumption can be saved. Power consumption in plating operations is largely dependent on the resistance of the plating solution filling the gap between the electrodes, and therefore it can be effectively reduced by shortening the distance between the electrodes. However, in reality, due to the vibration of the threading strip, poor shape (curvature), catenary, etc., the distance between the electrodes (h) must be about 251111 to prevent the shimmy due to contact between the strip and the anode. Therefore, it is not possible to reduce power consumption using the normal plating method.

As described above, it can be understood that there are various problems in the production of alloy electroplated steel sheets, and it is absolutely necessary to solve these problems, considering the recent growth in demand for alloy electroplated steel sheets. .

Many proposals have been made in the past regarding electroplating methods and apparatus intended for high current density operation. There are a wide variety of methods, but one that should be noted is the so-called cushion pad method, which applies static pressure to the strip that is passed through.

The basic idea is, for example, as shown in Figure 1 ((a) is a longitudinal side view and (b) is a partial perspective view)
A continuous slit nozzle hole (3) is provided on each front surface (25 (2')) of the (insoluble) anode (2) (2) facing on both sides of the anode (2) so as to surround a specific part of the electrode surface, and the electrolyte is Plating is performed while jetting the liquid toward the strip surface, and the part (I) of the strip surface surrounded by the jet impact position (I
) to generate static pressure. The advantage of this method is that the strip is supported from both sides by the action of static pressure, which prevents vibration of the strip and corrects defects in strip shape and catenaries (in the case of horizontal paths). Strip (1) and anode (
2) It is possible to realize so-called proximity electrolysis, in which electrolytic treatment is performed by bringing the two close together.

However, with this method, the flow of the interelectrode plating solution is inevitably weak in the static pressure generating part of the strip, and as a result, gas bubbles generated in that part tend to remain. Resistance becomes non-uniform depending on the position between the electrodes, causing variations in current density, resulting in an increase in plating voltage and, in the case of alloy plating, non-uniformity in the composition of the plating film and the precipitated phase. In addition, the plating solution flows strongly in the other inter-electrode parts compared to the above static pressure generating part, and in particular,
In the vicinity of the collision position of the nozzle jet surrounding the static pressure generation part, the plating liquid flows in the so-called Impinging Jet flow or W
This creates an all-jet flow and exhibits an extremely strong flow state, and this variation in the flow state of the plating solution depending on the position between the electrodes is a major problem that causes non-uniformity of the composition of the plating film and the precipitated phase. Cause.

In addition, the method shown in FIG. 1 has disadvantages in terms of repair. That is, generally, a PB gold alloy (with small amounts of Ag, Sn, Sb, 71°In, etc. added) is used as an insoluble anode for plating steel plates, etc., but when such an insoluble anode is placed in an acidic plating solution. When used, the lifespan is about six months to one year at most, and therefore periodic repairs are required.Also, if the strip breaks in the cell and the anode is damaged, or the nozzle hole (3) The plating solution flowing at high speed inside the nozzle may cause so-called erosion corrosion, resulting in uneven air flow from the nozzle hole, and an imbalance in the static pressure acting on both sides of the tube. Apart from this, repairs will also be required due to these factors. In the case of a type in which the nozzle hole is directly provided on the electrode surface of the anode, such repair cannot be carried out by partial repair such as replacing only the nozzle part or the anode body, which increases the cost.

The basic cushion pad method is shown in FIG. 1, but other advanced versions are also known. That is, as shown in FIG. 2, the anode (2) is placed near the center position in the strip running direction.
Separate from 2) is the plating liquid jet nozzle /L/ (hereinafter referred to as cushion pad nozzle) that applies static pressure to both sides of the IJ knob. Although there is no disadvantage in terms of repair compared to the above-mentioned method, the flow of the plating liquid in the i part near the nozzle jet collision position is extremely tight, which is the same as in the case of Fig. 1.
Therefore, it is desirable to have an alloy plating film with a stable and uniform composition and precipitated phase, but this method is no longer satisfactory for producing alloy plated steel sheets.

The present invention aims to provide an alloy electroplating method and apparatus that retains the inherent advantage of the cushion pad method in that proximity electrolysis is possible, and can continuously produce stable and high-performance alloy electroplated steel sheets. It is something.

That is, in the method of the present invention, for example, as shown in FIG.
(4), and as shown in FIG.
(Here, the jet collision position refers to the position (line) where the line (plane) extending from the center of the slit hole (3) intersects with the strip surface.) A position (T
) (T) The alloy plating is performed with the anode-side strip facing surface portion (S) located between them as a non-current area.

In the so-called cushion pad method, the flow of the plating solution becomes excessive near position 4, where the plating solution jet from the nozzle on the anode surface collides with the strip surface, and in the case of alloy plating, the performance of the plating film deteriorates. This will lead to

However, as a result of several experiments by the present inventors, α)−
(5) If the anode side strip facing surface part (S) located between the positions (1) and (T) is made into a non-energized band while maintaining the arrangement where the distance between the electrodes ≧ the distance between the electrodes (h) is satisfied, the above-mentioned jet It has been revealed that plating precipitation itself does not occur under excessive flow of plating solution in the vicinity of the collision location, its adverse effects are eliminated, and an alloy plating film with stable and good performance can be obtained.

In the present invention, the region of the anode-side string facing surface portion that is a non-current region is limited for the following reason. In other words, the flow of the plating liquid near the nozzle jet collision position (5) is a so-called Impinging Jet flow or Wa'll flow.
If the let flow is extremely large, it will have an adverse effect on the alloy plating deposition due to its excessive mass transferability. Specifically, for example, Zn-Nf system or Zn
-Fe-based alloy plating causes precipitation of η phase,
However, in order to completely eliminate the influence of such excessive plating flow on alloy plating and film performance, it is necessary to It is necessary to make the anode side strip facing surface portion (S) between the above-mentioned Cr(T) into a non-current area.

'In addition, in the cushion pad method, gas bubbles generated in the static pressure generating part (I) by the nozzle A/(4) generally tend to accumulate because the flow of the plating solution in that part is weak. In the method of the present invention, the static pressure generating portion (I
), the current is not applied, so the accumulation of such gas bubbles has no influence on the operation itself, and the problems associated with plating voltage and other problems are eliminated, and the present invention It can be said that the method has great advantages in this respect as well.

Next, the present invention also provides an apparatus for carrying out the above-described alloy plating method.

The device of the present invention can be used, for example, as shown in FIG. A cushion pad nozzle 1v (4) made of an electrically insulating material is provided adjacent to the end (5) in the strip running direction of the electrode surface (21), and this nozzle is inserted from each nozzle hole as shown in FIG. The jet impact position (5) and its corresponding nozzle front end (6) bordering the nozzle hole side electrode surface (21)
The distance (71) from the position (71) on the strip surface corresponding to the point where the normal line (plane) intersects the strip surface from the nozzle front end (6) is greater than or equal to the distance between the electrodes (h). In short, the cushion pad nozzle (4) on the anode side is formed of an electrically insulating material,
The strip facing surface (4i) of the nozzle
) (T), the anode side strip facing surface portion (S) is configured as a non-energized band. That is, the above (5)-
The reason why the distance between (1) is set to be equal to or greater than # for the electrode gap (h) is to ensure the non-energized band necessary for implementing the method of the present invention.

Hereinafter, the apparatus of the present invention will be explained in detail using specific examples.

First, in the apparatus of the present invention, it is essential to use a cushion pad nozzle, and specific examples of this nozzle are shown in FIGS. ) are a pair of slit holes (3) along the slope direction (3
), the ejection directions (,) (,) are parallel to each other and the strip (
In principle, it is perpendicular to 1). (+:9 and (c) both show examples in which the ejection directions (,), (,) are inclined inwardly. The one shown in Figure 4 above is also of this type. The plating liquid is supplied to each nozzle through the ladder (7) behind the slit hole (3).On each side, the plating liquid is supplied to the nozzle at the (8), (T) position, And these (5)
The distance CI> between - (T) is as shown in the figure, and the device of the present invention converts this distance (1) into the distance between poles (h
) The above is the above. In addition, all figures are noz/L/(
4) is provided to replace a part of the electrode surface (2), but in addition to this, the nozzle in the device of the present invention is
It is also possible to install it so that it is adjacent to the end (5) of the electrode surface in the strip running direction (see Figure 3); in this case, only on the side bordering the electrode surface! 〉
Needless to say, it is sufficient to satisfy the condition h.

Incidentally, from the original idea of the cushion pad nozzle, it can be said that the slit holes should be continuous in a circular shape as shown in Figure 1, but in actual plating equipment, usually the slit holes should be continuous in a circular shape as shown in Fig. Edge masking or plating for current control is applied on both the left and right sides of the width.
Since the side wall itself is approaching, there is originally little liquid flow in that direction, and therefore the pair of slit holes (3) (3) in the width direction of the strip is necessary. A slit hole in the direction connecting the two is not necessarily required. Depending on the type of Metxel, etc., the installation or non-installation may be determined as appropriate.

The above-mentioned cushion pad nozzle structure based on the present invention can be applied to any type of plating equipment in which plating is performed using an anode placed against the strip while holding the strip in a space and passing the strip through the strip. It is something. Some examples of application of the structure of the present invention are shown here. That is, FIG. 6 shows an example of application to a plating apparatus having a horizontal plating tank, in which cushion pad nozzles 1v ( 4) is installed. The one shown in FIG. 3 above is also of this type, and is an example in which a nozzle (4) is provided in the center of the anode (2) (2). Figure 7 shows an example of application to a vertical plating tank type plating apparatus, in which (a) shows insoluble anodes (
21(2) on the two sides in the strip running direction, and also at the center and the edge (5) in the strip running direction of the electrode surface.
A cushion pad nozzle (4) is installed in each of the holes. Note that (a) in the same figure shows a so-called immersion type plating apparatus in which the entire anode (2) is immersed in the plating bath (8), but in (b), the anode (2) is not immersed in the plating bath, but instead is placed in a cushion.・Injection of plating liquid from pad nozzle Iv (4),
This is an example of a so-called non-immersion type plating apparatus that performs plating by filling the gap (M) between the electrodes with a plating solution by supplying the plating solution.

The device structure of the present invention can thus be effectively applied to both immersion type and non-immersion type.

Next, the effects of implementing the present invention will be described using actual examples.

[Example l]

In the horizontal plating tank type plating equipment shown in Fig. 3, which uses a cold-rolled steel coil made by Sakaide 2501111 with a plate thickness of 0.4 mm and is equipped with a cushion pad nozzle/L/(4) of the type shown in Fig. 4, Zn. -Ni alloy plating was performed. At this time, the cushion/pad nozzle/L' (4) is designed to eject the plating solution so as not to generate a catenary at the center part of the strip between the anodes (the center in the strip running direction), and the distance between the electrodes (h) and the -T distance (j
) was plated with various changes.

The conditions for electrolysis are as follows.

Plating bath: (N1”)/(Zn”) concentration molar ratio 2.0
~3.0. Bath temperature 50-65°C, bath pH 1.5-2.5 Current density: 40-120 A/d♂ In-speed = 20-200 m/min Each plated steel plate obtained (plating composition: Ni 5-20wt) %, plating adhesion amount: 20 f/♂)K on one side, and the time until red rust appeared by a salt spray test was examined to evaluate corrosion resistance.

The results are shown in FIG. In the same figure, ○: Good corrosion resistance (red rust generation time 120 hours or more), ・: Same poor (red rust generation time 12 hours or more)
(less than 0 hours).

From the test results shown in the figure, it can be seen that no matter what distance (h) between poles is taken, if the distance CI> between T1 satisfies the condition t>h, an alloy plating film with good corrosion resistance can be obtained.

[Example 2] Using a cold-rolled steel coil of plate thickness Q, 4 wm, and 200 m of Sakaide as a plating bath, (Fe″+)/(Zn″)
Concentration molar ratio 1.0-2.5. Bath temperature 50-60℃, bath pH
Plating was carried out in exactly the same manner as in Example 1 above except for using a Zn-Fe-based bath of 1.5 to 2.0, and the following coating was performed on the obtained Zn-Fe-based alloy plated steel sheet. Corrosion resistance tests were conducted to evaluate performance.

<Post-painting corrosion resistance test> A plated steel plate was subjected to phosphate-based chemical conversion treatment, then electrocoated for automobile bodies (coating film thickness: 20 μmm), cross-cuts were made in the coating film, and salt water spraying was performed for 500 hours. Examine the corrosion status of the cross cut section by testing.

Figure 9 shows the test results. In the figure, ○: Good corrosion resistance after painting (blister width under the coating film 1.0 m or less), .: Poor corrosion resistance (width of the blister under the coating film 1.0 mB).

The test results in the same figure also reveal that for any distance between electrodes (A), the distance between T1 (A) is t>h, and an alloy plating film with good corrosion resistance can be obtained. There is.

As is clear from the above description, the present invention makes it possible to continuously manufacture stable, high-performance alloy electroplated steel sheets using a cushion pad method that realizes close-in electrolysis, which is effective in reducing power consumption. Therefore, it greatly contributes to improving the quality of various alloy-plated steel sheets and reducing manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the basics of the cushion pad method, where U) is a longitudinal side view and ←) is a partial perspective view. Fig. 2 is a schematic diagram showing a plating method using a cushion/pad nozzle, Fig. 3 is a plating device (horizontal plating frame type) incorporating a cushion/pad nozzle to explain the present invention in detail, Fig. 4 5 is a longitudinal side view illustrating the basic structure of the cushion pad nozzle used in the method of the present invention, and FIGS. In the vertical side view showing an example, (a) is a vertical jet type, and (b) and (c) are an inclined jet type. 6 and 7 respectively show examples of the arrangement of seven shimin pad nozzles based on the present invention, and FIG.
Ii′lj! An example of application to a @-type plating tank type plating device (using two electrodes with a nozzle on one side), and Figure 7 shows a vertical plating tank type plating device ((A) is for immersion viewing, and ``Gun'' is for non-immersion viewing. Application example (K) for the immersion type also uses 2 nozzles/I. (B) also uses 8 nozzles). Figures 8 and 9 show Zn using the cushion pad nozzle method.
In alloy plating, we investigated the relationship between the distance between T1 (a) with respect to the distance between poles M (b) and the performance of the plated steel sheet, and found that Figure 8 shows the Zn-Ni alloy plated steel sheet. Figure 9 shows the corrosion resistance of a Zn--Fe based alloy plated steel sheet after coating. In the figure, l: Nutrite, 2: Anode, 8 Nislit nozzle holes, 4 = Cushion butt nozzle ρ, 7: Header, 8
:Plating bath Applicant Sumitomo Metal Industries Co., Ltd. Applicant Mitsubishi Heavy Industries Co., Ltd. Patent attorney

Claims (2)

[Claims] (1) In a method in which alloy electroplating is performed continuously while the strip is running, a pair of Nutrit nozzle holes are provided along the width direction of the strip at corresponding positions of a pair of insoluble anodes arranged oppositely on both sides of the running strip. A nozzle is provided, and static pressure is exerted on both surfaces of the systrip by the ejection of electrolyte from the nozzle, and the jets from both nozzles collide with each other outward from each of the collision positions (A) and (A). The position (T) with at least the inter-electrode distance (h) in the direction
T) An alloy electroplating method characterized in that alloy plating is performed with the inner surface of the anode side strip rows located between them as a non-current area. (2) An apparatus that performs alloy electroplating continuously while a strip is running, in which the required corresponding portions of the electrode surfaces of a pair of insoluble anodes placed oppositely on both sides of the running strip are replaced, and/or An electrolytic solution jet nozzle /l/(4) made of an electrically insulating material is provided adjacent to the end of the electrode surface in the strip running direction, and this nozzle extends along the strip width direction to apply static pressure to the strip. It has a pair of merit nozzle holes (3) (3), and corresponds to the front end of the nozzle bordering the jet collision position (8) from each nozzle hole and the electrode surface (21) on the corresponding nozzle hole side. A continuous alloy electroplating device characterized in that a distance (4) from a position (T) on a Nutrip surface is greater than or equal to an inter-electrode distance (h).