JPS62211399A - Electrolytic cell for electroplating of alloy - Google Patents

Abstract

PURPOSE:To make an alloy compsn. uniform in the depth direction of a plating layer by providing plural flow regulating plates spaced from each other between electrodes and a strip so as to face the traveling direction of the strip to prevent the variance in the flow rate of plating bath jets. CONSTITUTION:The strip 1 is run between the electrodes 2 and 3 and the plating baths are gushed between the strip 1 and the electrodes 2, 3 from gushing headers 4, 5, by which the strip 1 is electroplated with the alloy. The plural flow regulating plates spaced from each other are provided between the electrodes 2, 3 and the strip 1 in the direction where the plates face the traveling direction of the strip 1. The plating bath jets which are emitted from the headers 4, 5 and flow in the direction opposite therefrom, therefore, flow between the top ends of the flow regulating plates 6 and the strip 1 and the blocking of the flow by the top ends of the plates 6 and the spread in the direction between the strip and the electrodes are obviated. The performance of the plating film is thus stabilized.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrolytic cell for alloy electroplating.

[Conventional technology]

In recent years, with the diversification and expansion of applications of products, there has been a demand for steel sheets with various surface textures, and alloy electroplating, which forms various alloy layers on the surface of steel sheets, has come into widespread use.

This plating method not only allows controlling the alloy composition of the surface film by adjusting the current density, but also allows the strip (1) and electrode (2) (3) to be separated as shown in Figure 8.
The alloy composition of the surface coating can also be similarly controlled by jetting a plating bath from the jet header (4) +5) between the strips and adjusting the flow rate of the plating bath near the strip +1) as appropriate.

[Problem that the invention seeks to solve]

However, as mentioned above, when the IcM gold bath was jetted,
When the alloy composition of the J-tube (1) surface film is controlled, an examination of the alloy composition of the formed plating layer reveals that it differs in the depth direction of the plating layer. This means that the jet flowing between the strip (1) and one pole (21 (3)) is between the jet header (4) (5) side and the opposite side.
This is because the flow velocity distribution is non-uniform as shown in FIG. 9.

On the other hand, Fe-Zn, Zn-Ni, Zn-
In the production of steel sheets electroplated with alloys such as Mn, the current density changes the alloy composition, film performance, etc. in the plating film, so it is necessary to make the current density uniform.

The present invention was devised in view of the above-mentioned problems, and aims to make the alloy composition uniform in the depth direction of the plating layer by effectively preventing variations in the flow velocity of the plating bath jet near the strip. It is something that we try to do.

[Means for solving problems]

First, the inventors proposed a strip (1) and an electrode (2) (3).
) The inventors have repeatedly investigated the cause of the non-uniform flow velocity distribution of the jet as shown in FIG. 9 when the plating layer is jetted from the jet header (41(5)). The conclusion reached was as follows: The plating layer coming out of the jet headers (4) and (5) was the same as the header (41 (
5) Since the jet is suddenly made to spread from the narrow space at the tip of the nozzle, the strip (1) and the electrode (21) flow from the jet header (4) (5) to the opposite side.
(Between 33 and 33, the flow gradually spreads in the direction between the strips -'-!L poles, and as a result, the flow velocity of the jet becomes slower at the end where it spreads.

Therefore, the jet of the plating layer coming out from the rudder f41 (5) to the jet does not spread between the electrode +21 (3) and the strip (1) while flowing from the jet header +41 (51 side) to the opposite side. If this can be done, the above problem can be solved.

The present invention was devised based on this basic point, and consists of an electrolytic cell for alloy electroplating having the configuration shown in FIG. i.e. electrode +21(3) and strip 11)
In an electrolytic cell for alloy electroplating in which alloy electroplating is performed while jetting a plating layer from a jet header (4) + 5) between the electrodes (2) and (3) and the strip (1), A plurality of rectifying plates (6) are provided at intervals in a direction facing the flow of the strip +11.

In this case, the rectifying plate (6) may be installed so that its end is in direct contact with the electrode +21 (3) as shown in the drawing, or it may be installed with a gap between it and the '1 pole (2) (3). Electric @ (2
1 (3) and the strip (1).

[For production]

By providing a plurality of rectifier plates (6) in this way, the plating bath jet that comes out of the jet header (41 (5) and flows to the opposite side thereof) flows between the tips of these rectifier plates (6) and the strip (1). The flow will flow between the current plate (
6) This prevents the strip from spreading in the direction between the strip and the electrode because it is blocked by the tip! As shown in Fig. 2, the flow velocity of the jet stream becomes approximately uniform between the jet stream header +41 +5) side and the opposite side.

Incidentally, since the rectifying plates (6) are provided at intervals in the direction opposite to the flow of the strip (1), there is almost no influence on the electroplating.

[Example 1] The present inventors installed lead-silver (p-silver) with a length of 1400 mm in a continuous double-sided electroplating apparatus consisting of 2 cells as shown in FIG.
b -Ag) *ノIEmcIQIjl)3]01)
and a jet header αOelm) with a nozzle gap (tl) 3 ym near the image output of each cell.
While providing a plating layer containing zinc sulfate (znso, ) and ferrous sulfate (FeSO,) as main components, and jetting the plating solution from the jet header (a) @ η Figure (9), Electric wave convergence of Fe--Zn alloy was carried out on both sides of the strip αO having a thickness of 0.7 mm.

At this time, the electric field @...(c) field 6η's) IJ knob σ0
On the side surface, a rectifying plate e4 (PVC!!) with a thickness (t,) of 3 sheets was placed in direct contact with the direction opposite to the flow of the strip (L3) with an interval (L3) of 140 m. The lengths of these rectifying plates were changed, and the distance (L,) between the strip opening and the straightening plate was 10 + m, 12.
Experiments were conducted in two cases: 5 m, 15 tm, 17.5 tm, and 20 gourds, and one without the rectifier plate (in the figure, 25 gourds).

Then, the plating layer was analyzed by GDS, and the distribution of Fe content in the depth direction was investigated.
Results were obtained showing the range of Fe content variation due to variation in the distance (L,) between IJ knobs 11 [1].

The plating conditions at this time were as follows.

Plating conditions Number of cells used: 2 Electrode length: 1400w+X2 Average current density: 50 A/dm Line speed: 15 mpm Deposition -* 15?/m
Liquid Fe50.・7H,0/(FeSO,・7H,0
+ Zn5O, 7H, 0) = 0.7pH = 2.
5 Strip thickness 0.7 m The fluctuation range of the F'e content in Fig. 4 is, for example, the maximum value a of the Fe content in the depth direction of the plating layer as shown in Fig. 5.
The difference between and at least 1 b is calculated.

As a result, as in the present invention, the current plate is used as an electrode (7)? υo
When it is provided between the IJ knobs σO, the fluctuation range of the Fe content is smaller than in the conventional method where it is not provided, especially when the current plate is provided between the IJ knobs σO ) to i u m.

In the case of 12.5+ms and 15 m, the variation range is 2% or less, which is a very significant effect compared to the conventional method, which has a variation range of about 10 mm.

In addition, in order to set the Fe content variation range in the depth direction of the plating layer to be extremely low in the case of this experiment as well as in other experiments as well.

The distance a'I (Lt) between the current plate and one strip αO is the nozzle gap (t, ) of the jet header ■ @ 1) e4 (goods).
It is preferable to set it to twice or less.

[Example 2] Next, the present inventors under the same plating conditions as in the previous example,
As shown in FIG. 6, the distance (Lt) between the current plate 11) and the current plate 97700 is 15 m, and the current plate e]) is connected to the electrode (
e) When the rectifying plate 6υ is separated from GIN (31) and the distance (L, ) between them is changed in steps of 1 in the range of 1 to 7, and as in the previous row, Electrode (a) a
]) Fe--Zn alloy electroplating was carried out separately for the case of contact with the field 0υ (case of L, =O).

Then, those plating Jfj were analyzed by GDS to examine the distribution of Fe content in the depth direction, and the results shown in FIG. 7 were obtained. Similarly to the previous example, the value of the Fe content fluctuation range in the figure is obtained by determining the difference between the maximum value and the minimum value of the Fe content in the depth direction of the plating layer.

As a result, the rectifier plate II) is changed to the electric current @1) C3[)
01) The fluctuation range of the Fe content is the smallest when it is in contact with the surface, and the current plate-one-electrode cl[110
]) As the distance (L, ) increases, the above fluctuation range gradually increases, and the increase in the fluctuation range becomes particularly noticeable in a range exceeding 3 m. Therefore, in the present invention, the % rectifier plate 611
It is most preferable to perform electroplating by directly contacting the surface of the electrode with a glossy surface of 0υ.
Even if a gap is provided between the current plate @〃-
It is appropriate that the distance between the strips α0 be less than or equal to the distance τ between the strips α0 (Lt).

Similar results were obtained in other experiments conducted by the present inventors.

〔Effect of the invention〕

As explained above, according to the electrolytic cell according to the present invention, since the rectifying plate is provided between the strip and the electrode, the flow of jet between the strip and the electrode is blocked by the tip of the rectifying plate, and the flow of the jet between the strip and the electrode is blocked by the tip of the rectifying plate, Since it will not spread in the direction between the electrodes,
This has the excellent effect of making the alloy composition uniform in the depth direction of the plating layer between the jet header side and the opposite side, thereby stabilizing the coating performance.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an electrolytic cell for alloy electroplating according to the present invention,
FIG. 2 is a graph showing the flow velocity distribution of the plating layer jet between the jet header side and the opposite side in the electrolytic cell, and FIG. 3 is a HL solution for alloy electroplating according to the first embodiment of the present invention. A schematic diagram of the tank, #JJ4 is a graph showing the results of the same example, FIG. 5 is a graph explaining how to determine the Fe content fluctuation range in FIG. 4, and FIG. A schematic diagram of an electrolytic cell for alloy electroplating according to an example, FIG. 7 is a graph showing the results of the same example, FIG. 8 is an explanatory diagram showing the configuration of a conventional electrolytic F4 machine, and FIG. It is a graph diagram showing the flow velocity distribution of the plating bath jet between the jet header side and the opposite side in the above solution 1 (particularly). In the figure, Hl (IG is a strip, (21 fi elf
(31GCI H is 1, +41 (4(lθ1) +
51Senyu0 indicates a jet header, and (6) indicates a rectifier plate. Patent applicant: Nippon Kokan Co., Ltd. Inventor: Toshi Tsujihara
Anan Tatsumen
Raw heavenly eyes crushing times
Yoshioka Yumuko, Sakamoto Norihiko, Patent Attorney, Yoshihara Sho, Tamayo
Kiyodai Takahashi 1
Figure 2 (Responsibility I Tsudai Rule) L2 (Ai I Ekibun - Stopzha Kaidandan) [m
mco Fig. 7 Lt ('IJ-'!u?m distance Qri [mml Fig. 8 Fig. 9 ('Towards the jet i...Brim rule)

Claims (1)

[Claims] Is there a jet header between the electrode and the strip? Alloy electroplating while spraying a plating bath In an electrolytic cell for alloy electroplating, between the electrode and the strip; Open each interval in the direction opposite the lip flow. The feature is that multiple rectifier plates are installed at the same time. Electrolytic cell for alloy electroplating.