JP4414819B2 - Partial plating apparatus and partial plating method - Google Patents

Description

  The present invention relates to a partial plating apparatus mainly used in field plating work. Specifically, the present invention relates to a partial plating apparatus that can perform plating with high current efficiency while maintaining a good working environment.

  Electroplating is usually carried out by causing an electrolytic reaction by energizing the object to be plated installed in the plating tank as the cathode and the plated metal as the anode, so that the anode dissolves and the same amount of metal is deposited on the cathode. Is called. In such a method, an object to be plated must be put in a plating tank, and is not necessarily suitable when plating a part of a large metal firing.

  On the other hand, a simple partial plating method known as brush plating is known. In this method, a plating treatment is performed by applying a brush or foam rubber containing an anode inside to a portion to be plated and energizing the brush or foam rubber while holding the plating solution. That is, a brush or foam rubber containing a liquid is used instead of a plating tank, and it is widely used because the equipment is simple and suitable for partial plating. In this case, an insoluble anode such as an insoluble metal electrode or a carbon electrode that is not deformed and does not wear out is usually used as the anode.

  However, since such an insoluble anode is used in such a partial plating method, sulfuric acid mist is generated in the sulfuric acid plating solution, and electrolytic gas such as chlorine gas is generated from the anode in the chlorine plating solution, and harmful gases are volatilized to the atmosphere during the work. Therefore, there was a problem of deteriorating the working environment and threatening the health of the worker.

  In particular, when the plating metal is a transition metal, the metal ions partially reduced at the cathode are oxidized again at the anode and returned to the ions with a higher valence, resulting in a reduction in power consumption. There was an inconvenience that it takes a long time to increase or process. In particular, in the case of precious metal plating such as platinum group metals, it is attracted to the anode because it is a complex ion having a negative valence instead of a metal ion, and a decrease in ions occurs at the cathode portion, and the liquid is made highly concentrated. However, the current density did not increase and the plating efficiency was poor.

On the other hand, in a conventional electroplating apparatus, an electrolytic gas generated from an insoluble anode is removed by a filter (see Patent Document 1), or an insoluble anode is encapsulated in a liquid-permeable bag (Patent) However, it is difficult to apply this as it is to a partial plating apparatus such as brush plating as it is.
Japanese Patent Laid-Open No. 2-7389 JP 2002-97598 A

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a partial plating apparatus capable of safely working while maintaining a good working environment. is there.

  Another object of the present invention is to provide a partial plating apparatus capable of performing a plating process stably and in a short time while maintaining high current efficiency.

  The above object of the present invention is achieved by the following means.

(1) An insoluble anode, a plating solution holding body provided around the anode , and a diaphragm provided in close contact between the anode and the plating solution holding body , wherein the anode has a hollow body structure A partial plating apparatus in which a large number of pores communicating with the outside and the hollow portion are formed in the wall portion of the anode.

(2) The method according to (1), further comprising electrolytic gas exhaust means for exhausting the electrolytic gas generated on the anode surface during the plating process and collected from the pores into the hollow portion to the outside of the system. Partial plating equipment.

(3) The partial plating apparatus according to (1) or (2) , wherein the anode is made of a titanium expanded mesh having a surface coated with an electrode material.

(4) the membrane is characterized in that it consists of inhibiting liquid permeable membrane permeation of metal ions or metal complex ions of the plating liquid, the portion of any one of (1) to (3) Plating equipment.

(5) The partial plating apparatus according to any one of (1) to (4), wherein the diaphragm is a thermoplastic resin film or an ion exchange resin film.

(6) The partial plating apparatus according to any one of (1) to (5), wherein the diaphragm is a polyethylene film or a polypropylene film.

  (7) The partial plating apparatus according to any one of (1) to (6), wherein the plating solution holder is a foam rubber or a brush shape.

(8) It further includes a plating solution adjusting means which is interconnected with the plating solution holder and adjusts the plating solution recovered from the plating solution holder and returns it to the plating solution holder. The partial plating apparatus as described in any one of 1)-(7).

  (9) The partial plating apparatus according to any one of (1) to (8), wherein the plating metal is a transition metal.

  (10) The partial plating apparatus according to (9), wherein the plating metal is a platinum group metal.

(11) A partial plating method using a partial plating apparatus provided with an insoluble anode and a plating solution holder provided around the anode, and collecting electrolytic gas generated on the anode surface during the plating process. and be exhausted to the outside of the system, the anode is encapsulated with a septum, which comprises suppressing the transmission to the anode side of the metal ions or metal complex ions in the plating solution, partial plating method.

  According to the partial plating apparatus of the present invention, since the anode is a hollow structure having a large number of pores, the electrolytic gas generated on the surface of the anode during the plating process is collected from the pores and passed through the hollow portion of the anode. Therefore, the plating process can be performed safely while maintaining a good working environment. Further, the exhaust efficiency of the electrolytic gas can be further improved by encapsulating the anode with a diaphragm.

  Further, according to the partial plating apparatus of the present invention, since the diaphragm is provided between the anode and the plating solution holder, the separation film suppresses the transmission of metal ions or metal complex ions in the plating solution, and anodization is performed. Therefore, the plating process can be carried out stably and in a short time while maintaining high current efficiency.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 and FIG. 2 are a longitudinal sectional view and a transverse sectional view showing the configuration of the electroplating apparatus according to this embodiment, respectively. In the drawings, the same reference numerals denote the same members. As shown in FIGS. 1 and 2, the electroplating apparatus 1 includes an anode 11, a diaphragm 12, and a plating solution holder 13.

The anode 11 is an insoluble anode, has a hollow body structure, and a large number of pores communicating the outside and the hollow portion are formed in the wall portion of the anode. Here, the plating solution used in the electroplating apparatus 1 includes a chlorine-based plating solution containing hydrochloric acid and chloride, a sulfuric acid-based plating solution containing sulfate, and the like. In the plating solution, an anodic reaction represented by the following formula (2) occurs, and in any case, an electrolytic gas (chlorine gas or oxygen gas) is generated at the anode 11.

  In the electroplating apparatus 1, the anode 11 has a hollow body structure having a large number of pores, so that the electrolytic gas generated on the anode surface is collected in the hollow portion 112 inside the electrode through the pores 111 of the anode 11, and the electroplating apparatus. It is possible to efficiently exhaust to the outside, prevent volatilization of harmful gases, and maintain a good atmosphere in the workplace.

  The anode 11 is not particularly limited as long as it is an insoluble anode having a hollow structure and having a large number of pores. For example, a porous plate made of titanium or the like or an expanded mesh is used as a base material, and its surface Further, iridium oxide, ruthenium oxide, etc. (so-called DSA) or platinum-coated insoluble metal electrodes such as platinum-plated titanium can be used. The shape of the hollow body of the anode 11 is not particularly limited, and is cylindrical, triangular, quadrangular, cone, pyramid, truncated cone, truncated pyramid, bell-shaped, bowl-shaped, bowl-shaped, bowl-shaped, bowl-shaped, inverted Any shape such as a bowl shape, a bell shape, and a beer barrel shape may be used.

  A diaphragm 12 is provided on the outer peripheral portion of the anode 11 so as to enclose the anode 11 and be in close contact with the anode 11. In the conventional electroplating apparatus, metal ions in the plating solution are reduced to metal at the cathode, and plating occurs. On the other hand, metal ions partially reduced at the cathode are oxidized again at the anode and ions having a large valence are original. There is a disadvantage that the power consumption of the plating process increases or a long time is required for the process. This tendency is conspicuous when the plating metal is a transition metal. In particular, in the case of noble metal plating such as a platinum group metal, the plating metal exists not as a metal ion but as a complex ion having a negative valence. Ions are attracted to the anode to cause a decrease in ions at the cathode, and there is a problem that even if the concentration of the plating solution is high, the current density does not increase and the current efficiency becomes extremely poor. In the electroplating apparatus 1, since the diaphragm 12 is provided so as to enclose the anode 11, movement of metal ions and complex ions in the plating solution to the anode side is restricted, and the above phenomenon is suppressed, and high current efficiency is achieved. Is achieved. Further, by encapsulating the anode 11 with the diaphragm 12, the electrified gas generated at the anode is more efficiently collected in the hollow portion 112 in the anode 11, so that the exhaust effect of harmful gas can be further improved.

  The diaphragm 12 is not particularly limited as long as it is a liquid-permeable film and can prevent movement of metal ions or the like to the anode side. For example, a fine hole such as a polyethylene film or a polypropylene film is formed. It is possible to use a thermoplastic resin film or an ion exchange resin film such as an anion exchange resin film or a cation exchange resin film.

  Further, a plating solution holder 13 is provided around the outer periphery of the diaphragm 12 so as to be in close contact with the diaphragm 12. The plating solution holder 13 is for holding the plating solution between the surface to be plated (cathode) of the object to be plated and the anode 11, has a solution holding property, has a corrosion resistance to the plating solution, and has an insulating property. The material and shape are not limited as long as they can contact the surface to be plated evenly. For example, foam rubber such as urethane foam or sponge rubber is processed into various shapes such as blocks. , Natural fibers, synthetic fibers or the like bundled, or woven fabrics, non-woven fabrics, felts, etc., and animal hairs made into a brush shape can be used.

  Next, a usage mode of the electroplating apparatus according to the present embodiment will be described. FIG. 3 is a diagram illustrating an example of an electroplating system using the electroplating apparatus 1.

  As shown in FIG. 3, the electroplating apparatus 1 fills the plating solution holder 13 with the plating solution 2, and joins the end of the plating solution holder 13 facing the anode 11 to the surface to be plated 3 of the object to be plated 3. And applied between the anode 11 and the object to be plated 3 (cathode).

  More specifically, a plating solution adjusting tank 42 is connected to the plating solution holding body 13 via a liquid feeding pipe 41, and plating is performed between the plating solution holding body 13 and the plating solution adjusting tank 42 by a circulation pump 43. Liquid 2 is circulated. In an electroplating apparatus using an insoluble anode, as the reaction proceeds, the vicinity of the cathode gradually tends to become alkaline and the vicinity of the anode tends to become acidic, the state of the plating film changes, and in some cases, hydroxide is generated. There was a problem. Therefore, in the electroplating apparatus according to the present embodiment, by forming a system that circulates the plating solution, a stable plating layer is always formed, and the adjusted plating solution is always supplied. Thus, a uniform plating process can be performed. However, it is not always necessary to circulate the plating solution depending on the composition of the plating solution to be used, the plating process conditions, etc., and a new plating solution is appropriately dropped onto the plating solution holder 13 with a dropper or the like as usual to replenish it. The plating solution may be recovered from the object to be plated as a waste solution.

  The anode 11 of the electroplating apparatus 1 is connected to the anode of the power source 52 via the cable 51, and the object to be plated is connected to the cathode of the power source 52 via the cable 51, and applied. The current supplied by the power source 52 is normally a direct current, but may include a pulsating current or an alternating current, and can be used properly depending on the application.

  Further, an exhaust pipe 61 is connected to the hollow portion 112 of the anode 11 of the electroplating apparatus 1, and gas generated at the anode 11 during the plating process and collected in the hollow portion 112 through the pores 111 passes through the exhaust pipe 61. The exhaust blower 62 exhausts the gas processing apparatus (not shown) or the outside of the work place. As a matter of course, the chlorine gas generated in the case of the chlorine-based plating solution also generates an electrolyte mist simultaneously with the oxygen gas even in the case of the sulfuric acid-based plating solution. As a result, it is possible to prevent volatilization of harmful gases into the room and to maintain a favorable atmosphere in the workplace.

  The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

Next, the electroplating apparatus of the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
[Example 1]

Using an expanded mesh made of titanium with an apparent thickness of 1 mm as a base material, a cylindrical body with a diameter of 30 mm and a length of 60 mm is made, and iridium oxide and tantalum oxide have a molar ratio of 80:20 on the surface thereof. The substance liquid was applied and baked to create an insoluble anode. A polypropylene bag having a thickness of 0.1 mm as a diaphragm was put on the outer periphery of the anode so as to be in close contact with the anode. In addition, polypropylene cotton was also packed between the bag and the anode so as to serve as a cushioning material so that sufficient liquid retention was performed between the diaphragm and the anode. Separately, a cylindrical urethane foam having a diameter of 60 mm and a thickness of 60 mm was prepared by providing a recess for fitting the diaphragm-attached anode, and the diaphragm-attached anode obtained above was fitted thereto. At this time, the lower end surface of the anode was set to 20 mm from the lower surface of the urethane foam. Thus, an electroplating apparatus as shown in FIG. 1 was produced. The upper part of the anode was fitted with a polypropylene funnel in the reverse direction, and the exhaust pipe was connected to exhaust the electrolytic gas. A 20 g / l aqueous solution of ruthenium chloride was soaked in urethane foam as a plating solution, and the surface of the cleaned nickel plate was plated. The plating process was performed at room temperature so that the current density on the nickel surface was 10 A / dm ² . The current efficiency at this time was calculated from the weight increase and found to be 40%. There was no odor around the work area.
[Comparative Example 1]

In Example 1, except that no diaphragm was provided on the outer periphery of the anode, an electroplating apparatus was prepared and plated, and the current efficiency was 5%. Chlorine odor drifted to the periphery. This is considered to be due to a decrease in plating efficiency due to volatilization of chlorine gas from the anode and anodization of ruthenium chloride.
[Example 2]

In Example 1, a plating apparatus was prepared in which a brush-like material in which polypropylene fibers were bundled instead of urethane foam was filled on the lower end surface of the anode with a polypropylene diaphragm sandwiched in a thickness of about 0.5 mm. A 50 g / l aqueous solution of chloroiridate was soaked in polypropylene fiber as a plating solution, and plating was performed at room temperature at a current density of 1 A / dm ² . Smooth plating was achieved with a current efficiency of 22%. On the other hand, when the diaphragm was removed and polypropylene fibers were directly attached to the anode, almost no iridium deposition was observed.
[Example 3]

An apparatus as shown in FIG. 2 was assembled using the apparatus prepared in Example 1, and continuous plating for a long time was performed. The surface to be plated was 500 × 500 mm, and plating was performed while moving the surface to be plated. The plating solution sucked up the surplus from the surface to be plated, adjusted the solution concentration in the adjustment tank, and returned it to the diaphragm portion. As a result, it was possible to perform plating for 3 consecutive hours at a current density of 10 A / dm ² and an overall current efficiency of 26%.

  The partial plating apparatus of the present invention is capable of safely working while maintaining a good working environment without volatilizing the electrolytic gas during the plating process, plating of large parts, plating of large parts, and other sites. It can be used for various partial platings that require treatment, and in particular, can be suitably used for partial plating of large products, for example, plating on the surface of a conductive material of an electric machine, rework plating of a plating peeling portion, and the like.

  In addition, the partial plating apparatus of the present invention can be used for various metal platings. Among them, for plating transition metals that are susceptible to anodization such as gold, silver, copper, zinc, chromium, nickel, tin, platinum, etc. In particular, it can be used suitably for plating of platinum group metals that are easily affected by the counter electrode such as platinum, palladium, rhodium, ruthenium, iridium, etc., all of which are stable plating with high current efficiency. Processing can be performed.

It is a longitudinal cross-sectional view which shows the structure of the electroplating apparatus 1 concerning embodiment of this invention. 1 is a transverse sectional view showing a configuration of an electroplating apparatus 1. FIG. It is a figure which shows an example of the electroplating system using the electroplating apparatus.

DESCRIPTION OF SYMBOLS 1 Electroplating apparatus 11 Anode 111 Pore 112 Hollow part 12 Diaphragm 13 Plating liquid holding body 2 Plating liquid 3 To-be-plated object 3 Continuous 41 Liquid feeding pipe 42 Plating liquid adjustment tank 43 Circulation pump 51 Cable 52 Power supply 61 Exhaust pipe 62 Exhaust blower

Claims (11)

An insoluble anode,
A plating solution holder disposed around the anode;
A diaphragm provided in close contact between the anode and the plating solution holder;
With
The anode has a hollow body structure, and a plurality of pores communicating with the outside and the hollow portion are formed in the wall portion of the anode.
Partial plating equipment. It further has an electrolytic gas exhaust means for exhausting the electrolytic gas generated on the anode surface during the plating process and collected from the pores into the hollow portion to the outside of the system ,
The partial plating apparatus according to claim 1. The anode comprises a titanium expanded mesh having a surface coated with an electrode material,
The partial plating apparatus according to claim 1 or 2 . The diaphragm is characterized in that it consists of inhibiting liquid permeable membrane permeation of metal ions or metal complex ions of the plating solution,
The partial plating apparatus of any one of Claims 1-3 . The diaphragm is a thermoplastic resin film or an ion exchange resin film.
The partial plating apparatus of any one of Claims 1-4. The diaphragm is a polyethylene film or a polypropylene film,
The partial plating apparatus of any one of Claims 1-5. The plating solution holder is foam rubber or brush-like,
The partial plating apparatus of any one of Claims 1-6. It further includes a plating solution adjusting means which is interconnected with the plating solution holding body and adjusts the plating solution recovered from the plating solution holding body and returns it to the plating solution holding body .
The partial plating apparatus of any one of Claims 1-7. The plating metal is a transition metal,
The partial plating apparatus of any one of Claims 1-8. The plating metal is a platinum group metal,
The partial plating apparatus according to claim 9. A partial plating method using a partial plating apparatus provided with an insoluble anode and a plating solution holder provided around the anode,
And evacuating the electrolysis gas generated in the anode surface during plating out the collected system,
Encapsulating the anode with a diaphragm, and suppressing the transmission of metal ions or metal complex ions in the plating solution to the anode side ,
Partial plating method.

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