JPS583998A - Electric alloy plating method - Google Patents

Abstract

PURPOSE:To calculate and replenish the consumption rates of metals accurately and continuously in the stage of replenishing the metals into a plating soln. as much as they are consumed in accordance with the electrolytic current values used for plating by making combination use of measurements of plating films and liquid compsns. by fluorescent X-ray analysis. CONSTITUTION:In order to control the compsns. of metals A, B in plating films at desired ratios, a strip 6 as the cathode is passed in the direction of (a) between the insoluble anodes 5 in a plating soln. 4 which is maintained at a constant ratio of concn. of both metallic ions. As the metallic ions are consumed on progression of the plating, the ratio of the concn. of both metallic ions deviates. Thereupon, the compsns. of the plating films are measured continously with a fluorescent X-ray analyzer 7, and if any change is produced in the concn. ratio of the soln., it is immediately instructed to an arithmetic device 8, which in turn determines the proportionally devided ratio of the electrolytic current for the constituting metallic ions in accordance with the results of said measurement. At the same time, it also determines current efficiency and inputs this to a computer 10, where the consumption rates of the respective metallic ions are computed from said proportionally devided ratio, the current efficiency and the electrolytic current value measured with an ammeter 9 at the point of measurement for said plating film compsn. These are instructed to storage tanks 11, 12 whereby required replenishing of A, B metallic salts is effected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the concentration of a plating solution in an electroalloy plating method using an insoluble anode.

Recently, in the field of plated products, there has been an increasing demand for high-performance plating that cannot be met with normal single metal plating such as Ni-Z.
Electroalloy plating, such as n-plating, has come to be carried out on an industrial scale.

In the electroalloy plating mentioned above, in order to improve the quality of the product, the ratio of the concentration of each metal ion constituting the plating solution (
It is extremely important to maintain a constant concentration balance of the plating solution (hereinafter referred to as the concentration balance of the plating solution), and a method of replenishing consumed metal ions from outside the system using an insoluble anode is generally used, which makes it easy to manage the concentration balance of the plating solution. ing.

In this case, there are two methods for measuring the amount of metal consumed in the plating solution. That is, there are two methods: one is to determine the amount of metal consumed by using the electrolytic current value used for plating, and the other is to determine the amount of metal consumed by directly measuring the composition of the plating solution. The former method using the electrolytic current value is based on the theory that in electroplating, the amount of metal that is equivalent to the amount of current applied is plated, so if the electrolytic current value is determined, the amount of metal consumed can be accurately calculated. . However, in alloy plating, the electrolytic current is consumed depending on the composition ratio in the alloy plating film.
If the coating composition changes, the concentration balance of the plating solution will be disrupted. Further, when the pH of the plating solution changes, the current efficiency changes, causing an error in calculating the amount of metal consumed based on the electrolytic current value.

In addition, methods for directly measuring the plating solution composition have conventionally been carried out by liquid analysis using batch methods such as atomic absorption spectrometry, but this method requires a long time to obtain measurement results, and There were drawbacks such as a delay in the timing of replenishment in response to fluctuations. In order to overcome the above-mentioned drawbacks, liquid measurement methods using fluorescent X-ray analysis have been attempted, but problems remain with the measurement accuracy of fluorescent X-ray analysis (a measurement error of about ±12/e occurs). Therefore, there are difficulties in obtaining high quality alloy plating.

As mentioned above, in electroplating, multiple metal ions are present in the plating solution, so it is difficult to accurately and continuously grasp the concentration balance of these metal ions. It has been considered difficult to continuously and stably obtain composite plating.

The present invention solves the above-mentioned difficulties at once and provides an electro-alloy plating method that can continuously obtain high-quality alloy plating for a long period of time.

That is, in electroalloy plating using an insoluble anode, the method of the present invention determines the plating film or plating solution composition using fluorescent X-ray analysis when replenishing the amount of metal consumed in the plating solution based on the electrolytic current value used for plating. By measuring the current efficiency and the electrolytic current proportion ratio for each metal acid fraction that makes up the plating solution, calculate the amount of each metal consumed in the plating solution from the obtained value and the electrolytic current value used for plating at the time of this measurement. The feature is that the consumed metal is calculated and replenished into the plating solution.

In addition, the method of the present invention incorporates a method using electrolytic current that can accurately and continuously calculate the amount of metal consumed in the plating solution, and a method for measuring the concentration of the alloy plating solution in fluorescent X-ray analysis. This made it possible.

The method of the present invention will be explained in detail below based on the drawings.

FIG. 1 is a partial schematic diagram of an example of a plating line for carrying out the method described in item 1 of the present invention, and shows a case in which, for example, electroalloy plating consisting of three types of metals, AlH, is applied.

In the figure (11×12) is a storage tank, which stores A metal salt and B metal salt, respectively, in order to replenish the A or B metal ions constituting the plating solution. (21822) indicates the quantitative cut-out device, and each metal salt of A1B is cut out in a fixed amount from the storage +% (11812) and put into the plating solution (4) of the plating tank (3). It melts and becomes A metal ion and B metal ion.

As the plating solution (4), metals that compose the alloy to be plated (hereinafter referred to as compositional metals, hereinafter referred to as metals and B metals) are melted in appropriately according to the composition ratio of the alloy. , after adjusting the pH if necessary, is used.

(5) are insoluble anodes, which are immersed in a plating solution and arranged in pairs, one on top of the other, at approximately equal intervals in the horizontal direction. (6) is a strip that moves in the direction of arrow a between the anodes (5) and (5) below while forming a cathode in the plating solution (4).

(7) is a fluorescent X-ray analyzer for measuring the plating solution film composition, and it continuously measures the plating film composition of the strip (6) at 5- immediately after being alloy-plated and leaving the plating tank (3). In this case, the balance of the A and B metals in the plating film composition is approximately the same as the concentration balance of the A and B metal ions in the plating solution. (8) is a calculation device that calculates the proportional distribution ratio of the electrolytic current for each liquid constituent metal ion based on the plating liquid composition measured by the fluorescent X-ray analysis, and also calculates the current efficiency based on the liquid composition. .

(9) is an ammeter that measures the electrolytic current value. 00 is a calculation device that calculates the amount of each metal consumed in the plating solution from the proportional division ratio and current efficiency of the electrolytic current determined by the calculation device (8) and the electrolytic current value measured by the ammeter (9). ,
Give instructions on the amount of each A and B metal salt to be cut out for each storage tank (11 x 12).

The concentration of A and B alloy metal ions in the plating solution in the plating line is controlled as follows. That is, the content of each of the compositional metals A and B in the plating alloy is A20%.
, B2O strip, plating solution (4) adjusted so that the content ratio of each metal ion of A and B is 14 A:B = 14 is used for plating. The strip (6) is used as a cathode in a tank (3) and moved between anodes (5) and (5) to perform alloy plating so that the alloy composition of the plating becomes A:B-1:4. However, in reality, each metal ion, A and B, has a different precipitation potential depending on the type of metal, so it is not always the case that A:B
No precipitation occurs at a ratio of =1:4. Also, the strip (
Since some metal ions are carried out of the plating bath (3) by step 6), the concentration balance of the plating solution is disrupted as plating progresses. Therefore, the composition of the plating film is continuously measured using fluorescent X-ray analysis, and if there is a change in the concentration balance of the liquid as a result of the measurement, an instruction is immediately given to the computing device (8) to conduct electrolysis based on the measurement results. The proportional distribution ratio of the current for each fluorescent ion is determined, and the current efficiency is also determined and input into the calculation device (10). The calculation device θO calculates the consumption amount of each metal ion A and B from the current proportion ratio and current efficiency and the electrolytic current value measured by the ammeter (9) at the time of measurement of the plating film composition, and calculates the consumption amount of each metal ion A and B. (11)(
12) respectively to perform the necessary replenishment.

Therefore, the concentration of each A1B metal ion in the plating solution during plating is controlled to be maintained approximately constant, and the strip (
6) is continuously plated with high quality alloy over a long period of time.

FIG. 2 is a schematic diagram showing an example of implementing the method of measuring the composition of a plating solution according to the present invention. In the figure, (11) is a fluorescent X-ray analyzer that measures the plating solution composition in a plating bath similar to that in FIG. After measuring the liquid composition and concentration balance, the tank (
3), plating tank (3) and fluorescent XM analyzer 0]
) is configured to circulate.

As a result of continuously measuring the plating solution (4) as described above, when a change occurs in the concentration balance of the solution, the calculation device 00 performs the same procedure as explained in FIG.
The consumed amounts of each of A and B ions are calculated, and the plating solution is replenished.

In addition, when fluorescent X-ray analysis is used in the method of the present invention, it is sufficient to have one fluorescent X-ray analyzer for one screening line, and the equipment cost does not increase. Further, since fluorescent X-ray analysis can be easily incorporated into an automatic replenishment device using a process computer, it is suitable for automating plating solution concentration management.

Next, the present invention will be described in detail with reference to Examples.

In the steel plate plating line shown in Figure 1, the width is 1000 m.
Ni-Zn alloy plating is applied to a strip measuring 0.8 m x 0.8 m thick. During plating, Ni and Znn in the plating film
The gold metal content is continuously measured using a fluorescent X-ray analyzer (7), and when a change occurs in the plating solution composition, a calculation device
In 8), the electrolytic current proportional division ratio and current efficiency for each NisZn ion were determined based on the measurement results, and the electrolytic current value measured by the ammeter (9) at the time of the measurement was used to determine the electrolytic current proportion and current efficiency for each NiZn metal. Calculate the consumption of ions,
The storage tank (11' x 12) was instructed to be replenished with the required Ni metal salt and nickel metal salt.

The plating conditions were as follows.

■ Plating solution: ZnSO4・7FI20 90 f
/IJNiSO4・6I-I20 250? /l+p
H2,0 Temperature 60°C ■ Plating current density 40 A/d m"9- Also, as a comparative example, the same plating as above was performed using the conventional method of determining the amount of metal consumed only from the electrolytic current value without performing fluorescent X-ray analysis. Ni-Zn alloy plating was performed under the same conditions as above.

Fig. 3 is a chart comparing the results of measuring the ratio (balance) of octopus ions and Zn ions in the plating solution for the above two examples. In the figure, P indicated by a solid line indicates the Ni1Zn balance of the comparative example. The characteristic curve Q indicated by a broken line is the characteristic curve of the N1% Zn balance of the example of the present invention.

As seen in the figure, the comparative examples often show compositions in which the Ni and 7n balances far exceed the fluctuation control limits (+1, -1); , Zn balance showed a value within the control limits, and was maintained almost the same as at the start of plating even after 48 hours. The plating film of the steel plate made by Kempo is of a beautiful and shiny quality, and the I'J in the plating film is of a beautiful quality.
As a result of investigating the respective contents of i and Zn, it was found that the ratios were approximately the same as those of the plating solution, and the composition was uniform throughout with very little variation.

Separately, when the method of the present invention using fluorescent X-ray analysis of the plating solution composition was carried out in the same manner as described above, the NizZn balance of the plating solution was the same as in the embodiment of the invention described in section 1 above. remained approximately constant within control limits over a long period of time.

As explained above, the method of the present invention uses a new method of calculating the amount of metal consumed in the plating solution based on the electrolytic current in combination with the measurement of the plating film composition or plating solution composition by fluorescent X-ray analysis. For alloy plating, the amount of metal consumed in the plating solution can be accurately and continuously calculated and replenished, resulting in a significant improvement in the accuracy of concentration control of the plating solution, resulting in high quality. It has a great effect on the industrial production of electroalloy plated products.

[Brief explanation of drawings]

Fig. 1 and Fig. 2 are partial schematic diagrams showing the electroplating line of a steel plate in which the method of the present invention is carried out, and Fig. 3 shows N1 ions in the plating solution in the embodiment of the method of the present invention and the conventional example.
It is a chart comparing changes in the concentration balance of ions. 1112: storage tank, 2+ 22: cutting device, 3: plating tank, 4: plating solution, 5: insoluble anode, 6: strip, 7.11: fluorescent X-ray analyzer, 82 calculation device, 9: ammeter, 10: Calculating device, 12: Circulation pump 182 diagram #13 Diagram voluntary procedure amendment 1 Indication of case 1982 Patent application No. 102648 2 Name of invention Electroalloy plating method 3 Compensation person case Related Patent Applicant Address 5-15 Kitahama, Higashi-ku, Osaka Name (211) Sumitomo Metal Industries Co., Ltd. Representative Kuma
Norifumi Tani 4 Agent 5 Date of amendment order 6, Detailed explanation of the invention column 7 of the specification subject to amendment, Line 4 from the bottom of page 6 to page 9 of page 7 of the specification of the contents of the amendment, The statement "The concentration balance of the plating solution will be disrupted for the composition metal A1B of the plating alloy" is corrected as follows.

Claims (1)

[Claims] (1) In electroalloy plating using an insoluble anode, when replenishing the amount of metal consumed in the plating solution based on the electrolytic current value used for plating, the plating film composition or plating solution composition is measured by fluorescent X-ray analysis. By this, the current efficiency and the electrolytic current proportion ratio for each metal acid fraction constituting the plating solution are calculated, and the amount of each metal consumed in the plating solution is calculated from the obtained value and the electrolytic current value used for plating. An electro-alloy plating method characterized by replenishing the inside.