JPH11303041A - Pollution preventing method for structure in contact with sea water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochemical method for preventing or restricting the sticking of marine living organisms, which is gentle to the environment and excellent in workability and re-processability. SOLUTION: Surface of a structure in contact with sea water 61 is constituted with a base material consisting of titanium, a solution containing cobalt or manganese is coated to the surface of titanium, and it is converted into cobalt oxide or manganese oxide by thermal activated treatment. Using the titanium covered with oxide as anode and maintaining the potential generating only oxygen without generating chlorine, the sticking of marine living organisms to the structure at the interface between the structure and sea water can be restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the prevention of adhesion of marine organisms (including seaweeds) which inhabit and grow on the interface of concrete or metal (mainly steel) structures in contact with seawater and cause various troubles. .

[0002]

2. Description of the Related Art Metal structures such as piers, seawalls, intake channels and other concrete structures, steel sheet pile quays, steel pipe piles, oil drilling rigs, screens, pumps, jellyfish prevention wire meshes or heat exchangers that are in contact with seawater are: Marine organisms (including seaweeds) that grow on and adhere to the interface of these structures cause various troubles.

[0003] In the case of a water channel or a cooling pipe, the amount of water is reduced due to blockage of the pipe, the cooling effect is reduced, or the operation of the next process plant is greatly affected. In the case of metal structures, localization of corrosion is inevitable due to the attachment of marine organisms, and it is also important to impair the aesthetics of revetments and piers.

[0004] Measures for preventing marine organisms from adhering to the structure (hereinafter, referred to as antifouling) include introducing chlorine or hypochlorite into the environment, generating toxic ions such as chlorine and copper by electrolysis, or preventing. The application of a soil paint has been developed and put to practical use.
However, most of these are based on toxic ions, killing not only the marine organisms but also useful organisms,
In addition, since the concentration is controlled to be high in order to enhance the effect and maintain the effect for a long period of time, excess ions are likely to cause environmental pollution.

[0005] In a heat exchanger or a condenser using seawater as cooling water, large marine organisms such as barnacles and mussels adhere to the tube plate at the inlet or outlet of the cooling pipe and block the diameter of the cooling pipe. Although the sponge ball is removed through a cleaning sponge ball, there is an example in which the sponge ball cannot pass or is clogged, and the operation is stopped without stopping to remove marine organisms. In particular, it is remarkable in a titanium tube sheet having more excellent corrosion resistance than a copper alloy tube sheet.

Although non-toxic or harmless antifouling measures have been actively researched and developed in recent years, silicone-based antifouling paints and zinc sprayed coatings are not only effective but have a service life and construction cost of at least 1,000 m ^2. It is desirable to develop simpler methods for dealing with large objects and semi-permanent existing facilities. The surface of the target structure is coated with a conductive paint containing a conductive material such as carbon or graphite, and the conductive paint film is used as an anode to generate hypochlorite ions or chloride ions, thereby preventing the surface of the structure from being stained. The method is, for example, Japanese Patent Publication No. 6-15069, 8
-14036, Patent Nos. 2601807 and 257
No. 5,866. In addition, a conductive sheet is lined on the part of the object to be stained that requires antifouling, and an electrode material, a reference electrode and a DC power supply are separately installed in the same environment,
Japanese Patent Publication No. Hei 7-24822 discloses a method in which the conductive sheet is used as an anode, the electrode material is used as a cathode, and the potential difference between the reference electrode and the anode is kept constant to prevent microorganisms touching the conductive sheet from adhering due to an electric shock. It is described in the gazette. Such conductive paints and conductive sheet linings are inevitably deteriorated by chlorine and hypochlorite ions generated by electrolysis in addition to the life of the conductive material carbon and the adhesive resin binder, and cannot withstand long-term use. And the rework is not ready depending on the shape, size or environment of the structure. In concrete structures, paint and sheet coating are not easy to test for deterioration of concrete.

[0007] Other non-toxic or harmless antifouling methods include WO 93/022, filed by the applicant of the present invention.
No. 54 publication. This is because steel, which has no harmful eluting ions, is attached to the interface with seawater of the object to be contaminated and electrode materials are separately installed in the seawater environment, and the former steel is connected to the positive electrode of the DC power supply to form the anode, The electrode material is connected to a negative electrode to form a cathode, and a current is supplied at an anode current density of 1 A / m ² or less to suppress the generation of chlorine (anode potential is kept at 1.1 V-SCE- or less) while marine organisms are present on the steel surface. This is a method for suppressing the formation of slime. A similar method is disclosed in Japanese Patent Publication No. 1-46595.
This means that an electrocatalytic film (mainly a platinum group metal or an alloy based on these metals or an oxide of these metals) is formed on the surface of a metal (for example, a titanium heat exchanger) in contact with water (including seawater). Then, electrolysis is performed as an anode, and sufficient oxygen is generated without substantially generating chlorine gas so that organisms and scale deposits are not present. These methods are attracting attention as environmentally harmless methods, but they require expensive electrode materials and on-site construction man-hours compared to the expectation of long-term effects, and the difficulty is that construction costs are higher than other methods. Has become a major factor for practical use.

[0008]

SUMMARY OF THE INVENTION The present invention provides an antifouling method which is environmentally friendly, has antifouling properties over a long period of time, is easy to construct, and is easy to repair. In addition, it is another object of the present invention to improve the antifouling effect and reduce the construction cost as compared with the conventional antifouling method using the electrolytic method.

[0009]

In order to solve the above problems, the present invention has an antifouling effect equal to or higher than that of the conventional antifouling means, the electrode material is inexpensive, the construction work is safe and easy, and the life is long. The present inventors have made intensive studies on the development of a catalyst-coated electrode and completed the present invention.

The means are as follows. The basic means is to apply titanium spray to the surface of the antifouling object of a structure (made of metal or concrete) that comes in contact with seawater, and a solution containing cobalt or manganese or a solution obtained by mixing iridium with these solutions on the sprayed coating After applying and drying,
An object of the present invention is to convert the thermal sprayed coating to a cobalt oxide or manganese oxide coating by anodic or flame excitation and performing a thermal activation treatment. The titanium sprayed coating on which the cobalt oxide or manganese oxide coating has been formed is formed as an anode in seawater by maintaining the anode potential within the oxygen generation potential and performing seawater electrolysis at a potential lower than the chlorine gas generation potential. This is a method for suppressing or preventing the adhesion of marine organisms (including algae) to the surface of the object to be stain-proofed.

[0011] Depending on the target structure, the titanium sprayed coating covering the surface of the structure is a titanium plate or a thin strip,
It is also possible to form the above-mentioned cobalt or manganese oxide film beforehand at a factory, transport it to the site, and attach it to an object.

In the case of a heat exchanger composed of a titanium tube sheet or a tube, there is no need to prepare titanium spray or titanium strip in advance, and after cleaning the surface of the titanium tube sheet with kelenium, directly remove cobalt or titanium. A manganese-containing solution or a solution in which iridium is mixed with these solutions is applied, dried, and then heated with a flame or electric heat to transform it into cobalt oxide or manganese oxide.

In the present invention, these oxide film-forming titaniums function as electroactive catalysts. The titanium having the electroactive catalyst is connected to the positive electrode of an external DC power source to form an anode, and the anode potential in seawater is changed to 1.
1 V (SCE standard), which is lower than 0.
The voltage is controlled by a constant potential device so as to be maintained at 5 to 1.0 V.

When the cobalt oxide or manganese oxide has been consumed, a solution containing cobalt or manganese or a solution obtained by mixing iridium with these solutions is applied directly to the titanium sprayed or titanium surface and dried, and then heated with a flame or electric heat. Can be easily reproduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In implementing antifouling means, a condition to be kept in mind is that, in addition to the antifouling effect, adverse effects on the surrounding environment are minimized. Avoid environmental cross-contamination. Antifouling due to toxic ions such as chlorine gas and heavy metal ions such as copper generated by seawater electrolysis removes even more useful marine organisms than the antifouling effect, and easily causes environmental pollution. Therefore, a non-toxic, harmless and pollution-free antifouling method has been desired, and its development has been spurred. Non-polluting antifouling paints and electrolytic antifouling methods that do not generate chlorine have been developed.
However, in this method, as described above, reduction of the total cost is a major problem. In the case of electrolytic antifouling, it is important that the electrode material, electrode shape, construction means, reprocessing, etc. be inexpensive, have excellent workability, and have a long expected life.

Electrolytic antifouling is broadly classified into a method utilizing anodic dissolution of a soluble metal (for example, steel) and a method of generating chlorine or oxygen gas by seawater electrolysis of an anode using an insoluble electrode.

The present invention is intended to reduce construction costs by focusing on antifouling by oxygen gas without generating chlorine gas by performing seawater electrolysis with an insoluble anode.

The primary electrochemical reaction of the anode surface in seawater electrolysis using an insoluble _{^{anode, 2Cl - → Cl 2 + 2e}} - ·········· (1) 2H 2 O → O 2 + 4H + + 4e - ... (2)

In order to suppress the generation of toxic chlorine gas, the potential must be maintained at a lower (base) potential than the potential at which chlorine is generated. In seawater, this potential is 1.37 V on hydrogen electrode basis (1.13 V on SCE [saturated calomel electrode basis]).
V). In a solution having a low salt content, the chlorine generation limit potential is slightly higher. In the antifouling of the present invention, it is necessary to suppress the potential to below the chlorine generation limit potential. The oxygen generation limit potential increases as the pH of seawater decreases, but the pH increases to 6.5 to 6.5.
In the range of 8.5, 0.87 to 0.71 V (0.
63 to 0.47 V). It is 0.76 V (0.52 V in SCE) at pH 8.2 of standard seawater. Considering standard seawater (pH 8.2), 0.76V (0.5 at SCE)
1.37 V at a potential higher than 2 V) (1.13 V at SCE)
If the potential is kept lower than V), oxygen is generated from the anode surface, but generation of chlorine can be suppressed. The anode potential is a function of the applied anode current density, the higher the current density, the higher the potential and the generation of oxygen increases in proportion to the current flow. In other words, if the anode potential is controlled in the range of 0.5 to 1.1 V by SCE in seawater, no pollution is generated without generation of chlorine. From equation (2), 4 moles of hydrogen ions (4H ⁺ ) are generated at the anode interface, which cannot be measured, but are indirectly in the pH range of 1 to 3 and in the high acidity range. It contributes to the control of marine organisms.

The vicinity of the anode is maintained in an extremely strong oxidizing atmosphere due to the generation of hydrogen ions and the generation of oxygen and the generation of chlorine ions and chlorine when oxygen is generated. An insoluble electrode that is less consumed (negligible) even if the anode current flows for a long time in such an environment needs to be made of a material that is strong against oxidation and chlorine and has excellent conductivity. A simple substance of carbon or a conductive paint using carbonaceous as a conductive material has a problem in that the oxidizing agent in the environment rapidly diffuses and escapes from the interface, or the applied anode current density is small (for example, several tens mA / m ² or less), and is one month to one month.
Regardless of the condition of short-term use for about a year, carbon dioxide is oxidized and consumed undesirably under large current and long-term use. Titanium, known as Valve metal, is excellent against oxidation and chlorine, but the oxide film is strong, and as a conductive material, the additional voltage will be large as it is, and the breakdown voltage of titanium is about 8V. Not proper. Therefore, in the electrochemical industry, titanium materials coated with platinum-based metals or oxide catalysts of these noble metals are used. The catalyst-coated titanium electrode is plate-shaped,
Even if it is net-like, there is a manufacturing process such as catalyst coating, and it is an expensive coating, so that on-site work and reprocessing are not easy.

The above-mentioned Japanese Patent Publication No. 46595/1994 discloses a catalyst-coated valve metal in which a surface of a valve metal is coated with an electrocatalyst (for example, a platinum-based metal or a mixture of these noble metal oxides) as an anode. There has been disclosed a technique of performing electrolysis and generating oxygen without generating chlorine to prevent contamination. Regarding this case, the applicant who is a similar trader has not heard of an example that has been put to practical use aside from the theoretical effect. For example, coating such as an electrocatalyst mixed with platinum-based metal or these noble metal oxides on the tube plate of a titanium heat exchanger,
The target to be coated is large, and expensive catalyst processing means requires a large capacity even in factory production.Moreover, it is not suitable for on-site production and it is not easy to rework, so it is suitable for practical use unless the process is complicated and total cost is reduced. is not.

In view of this point, the present inventors have developed a method and a method which can easily coat a valve metal such as titanium on the surface of a structure (for example, concrete or steel) other than a structure made of titanium. The present inventors have conducted intensive studies on a catalyst that can replace the above expensive noble metal-based electrocatalyst and a catalyst coating method.

As a result, a titanium or thermal spray coating is applied to the surface of the target structure with a flame or an arc, and a cobalt or manganese solution or a solution obtained by mixing these solutions with iridium is applied to the surface, and after air drying, the flame or electric heating is performed. It is achieved by heat activation treatment with heat excitation to convert to cobalt oxide or manganese oxide. Regardless of whether the object is a reinforced concrete structure or a steel structure, the surface is blasted or polished, and then spray-coated by flame or arc using a titanium wire of 0.8 to 3.2 mmφ. The thickness of the coating is not particularly limited, but is 50 to 15
It is practical to set the range to 0 μm. When the target is a metal structure, titanium spraying may be performed directly, but titanium spraying is performed after applying a pre-treatment coating such as a heat-resistant and insulating paint on the water-contact surface of the structure. Is good. A cobalt nitrate solution or a manganese solution or a solution obtained by mixing iridium with these solutions is applied to the titanium spray-coated surface by spraying or brushing. The coated surface is preferably 20-30
After air drying, the coated titanium sprayed film is anodically tens of mA
/ M ² or excited by flame and converted to cobalt or manganese oxide. As a result, the cobalt oxide or manganese oxide forms an active and adhesive film on the surface of the titanium sprayed film. In the case of a titanium structure, the surface of the titanium structure is cleaned and then directly sprayed or applied with the above-mentioned cobalt nitrate solution or manganese nitrate solution, or a solution obtained by mixing iridium with these solutions, and thermally activated. By performing the treatment, an electroactive catalyst film is formed. Instead of the thermal spray coating, a titanium strip having the catalyst coating formed on the surface of the structure may be manufactured in a factory, transported to the site, and attached to the surface of the target structure by conventional means. Regardless of which method is used, compared to conventional platinum-based metal or these noble metal oxide film forming means,
Equipment, work method or total construction time is greatly reduced, and cost can be reduced to 1/5 to 1/10.

The properties of the titanium material serving as the anode electrode substrate are as follows. When the target structure is concrete (including reinforced concrete), a titanium spray coating is used, and when the steel structure is a titanium structure, a titanium spray coating or a titanium strip is used. Is done.

The cobalt solution applied to the titanium metal coating is preferably a nitrate, and the manganese is preferably a nitrate or sulfate solution. Further, by adding iridium to these solutions, it is possible to enhance the adhesion of cobalt oxide or manganese oxide to the underlying titanium by thermal activation treatment after coating, to stabilize the performance as an electrocatalyst, and to extend the life.

The titanium oxide coated with cobalt oxide or manganese oxide formed on the surface of the target structure is connected to the positive electrode of an external DC power source in seawater to serve as an anode, and a saturated calomel electrode is referred to as a reference through a potentiostat. Set current is applied to 0.5 to 1.1 V as an electrode. When the set potential exceeds 1 V, the anode current density fluctuates because the frequency of repeating dissolution and regeneration of the electrode coating increases, but is about 0.1 to 1 A / m ² . In the present invention, it is important to generate only oxygen without generating chlorine to prevent stains.
It is important to keep the potential of V. That is, the electrode maintains the anode potential in the above range even when the current fluctuates, is hardly damaged, and can be easily reworked even if damaged, and the present invention is an antifouling method using the same.

[0027]

EXAMPLES Test Example 1 (Positive Polarization Characteristics of Titanium, Noble Metal Oxide Catalyst Coated Titanium and Cobalt Oxide Coated Titanium in Sea Water) An electrode material obtained by coating a noble metal oxide catalyst and a cobalt oxide catalyst on a titanium substrate was subjected to constant potential in sea water. The test was performed by the anodic polarization method. Seawater was at room temperature (21-23 ° C) and pH was 7.8. The result is shown in FIG.

The following was found from the results shown in FIG. Since titanium alone has a strong oxide film formed on the surface of titanium, it exhibits a passivation behavior and exhibits an oxygen generation region of 0.5 to 1.1.
In the case of V, the passivation maintaining current alone exceeds the chlorine generation potential of 1.1 V with a slight change and is not suitable as an electrode material.
Noble metal oxide catalyst or cobalt oxide coated titanium
Even if the potential slightly rises from the natural potential in each seawater, outflow of current is observed. In addition, the outflow of the current increases almost in proportion to the rise of the potential. The positive polarization of the noble metal oxide catalyst coating increases almost linearly until it reaches the chlorine evolution potential. The branch point of the oxygen evolution potential is not clear. In the case of titanium coated with cobalt oxide, there is a branch point where the anode potential is around 0.5 to 0.6 V, which corresponds to the oxygen generation potential. That is, by maintaining the anode potential of the cobalt oxide-coated titanium electrode between 0.5 V and 1.1 V, which is a chlorine generation potential, only oxygen is generated from the electrode surface.

When the anode potential is up to 0.9 V, the anode current density of the cobalt oxide-coated titanium electrode is higher than that of the noble metal oxide-coated titanium electrode, and the amount of generated oxygen is large.
At (noble) potentials higher than 0.9 V, both electrodes have similar performance. In other words, since the cobalt oxide-coated titanium electrode generates much oxygen at a lower potential, more environmentally friendly antifouling can be expected. The applied anode current density is not clear because the polarization progresses with the energization time, but is initially 0.1 to 1.0 A / m ² and is determined to be maintained within the above potential with a low current over time. it can.

Test Example 2 (Amount of Gas Evolved from Electrode Surface at Anode Set Potential) Based on the results of Test Example 1, cobalt oxide-coated titanium was placed in seawater at 0.9 V and 1.15 V (both SCE The gas generated from the electrode surface was collected at an anode potential of (reference) and analyzed by gas chromatography.

As a result, at 0.9 V, the main component was oxygen. At 1.15V, about 90% is chlorine and the remaining 10%
% Was oxygen. That is, the set potential of the anode is lower than the chlorine generation potential (base), and the oxygen is likely to generate high (noble).
By setting the potential, non-polluting antifouling by oxygen can be expected without generating chlorine.

Test Example 3 On the basis of the above test results, the surface of the concrete block was sprayed with titanium and further formed with a cobalt oxide coating, immersed in seawater and anodized to conduct marine organisms on the coating surface. The adhesion situation was investigated.

FIG. 2 shows an outline of the test apparatus. Reinforced concrete block 4 length and width 25cm, thickness 10c
The four round steel bars having a diameter of 12 mmφ and a length of 30 cm were assembled in a m shape and placed in the concrete so that the fog was 5 cm. After sandblasting one surface of the block, a titanium wire rod having a diameter of 1.2 mm was spray-coated by arc spraying so as to have a thickness of about 150 μm. After the tar epoxy coating, antifouling treatment was performed with a silicone antifouling paint except for the sprayed surface. The sprayed surface was coated with cobalt, its iridium-containing solution, or manganese-containing solution. Cobalt and manganese are hexahydrate nitrates at 260-300 g / L. 15-20 g / L of iridium chloride (IrCl ₄ .H
_The solution to which 2O) was added was applied. After application, 20-30
After drying for a minute, the coating was heated and dried with a gas flame to obtain the oxide-coated concrete block 1 by titanium spraying.

The oxide-coated concrete block 1 was hung with rope in seawater of Tokyo Bay and held at the anode set potential in four stages using a potentiostat 5 (reference electrode SCE3) for about 7 months. Dipped. The set potentials are 0.7, 0.8, 0.9 and 1.0V. One untreated concrete block 1 was separately installed for comparison.

After the immersion for about 7 months, the weight of attached marine organisms was measured to determine the antifouling rate. The antifouling rate was calculated by the following equation. Antifouling rate (%) = (wet weight of blank specimen−wet weight of specimen) / wet weight of blank The test results are shown in Table 1.

[0036]

[Table 1]

The higher the anode set potential, the higher the antifouling rate, and at 0.9 to 1.0 V, the adhesion of marine organisms can be substantially ignored. The addition of iridium tends to have a somewhat higher antifouling effect, but is slightly different from the effect of other coatings. Rather, it suppresses a decrease in the effect, and is durable and enhances the adhesion to the substrate. In addition, the uniform gray-black color of the finished surface has a good appearance.

The attached marine organisms are algae, hydros,
Large marine organisms such as barnacles and mussels were hardly attached. On the blank concrete, mussels adhered as thick as 10 to 15 cm and the silicone-based antifouling paint surface was also involved and adhered.

Example 1 Based on preliminary test results, the present invention was applied to a practical concrete structure. The electrolytic antifouling device of the present invention was applied to a concrete wall surface of an intake channel practically used by a power company. An overview of the installation situation is shown in FIG. FIG. 3A is a perspective view, and FIG. 3B is a sectional view thereof. The 2 m × 2 m of the concrete wall 41 of the screen room was masked 11 and dirt was removed by sandblasting, and then titanium spray of about 150 μm thick was applied by arc spraying using a 1.2 mmφ titanium wire.
Next, a 260 g / LCo (NO ₃ ) ₂ .6H ₂ O solution was applied to the sprayed titanium coated surface 11. After draining and drying, it was activated by heating and exciting with a gas flame. The titanium ribbon 12 was used as a conductive material from the titanium sprayed surface 11 to the connection portion of the cable 7 above the ground. The titanium ribbon 12 and the titanium sprayed portion 11
The surface was fastened with an anchor bolt 13 made of titanium. A reference electrode (SCE) 31 (not shown) was inserted into the PVC tube 15, and the PVC tube 15 was fixed to the concrete wall surface 41 with metal fittings. The wiring was started up inside the PVC pipe 15 to the ground, and connected to a potentiostat (constant potential device) 51.

The energization was performed at a set potential of 1.0 V for about one year. The marine creatures such as mussels, barnacles, sea squirts, and algae were attached to the concrete wall surface 41 of the intake channel 40 where the apparatus of the present invention was not installed in a thickness of 10 cm or more. On the wall surface 11 on which the present apparatus was installed, attachment of hydro was partially observed, but attachment of large marine organisms such as mussels, which are difficult enemy of the intake channel 40, was not observed.

Example 2 The electrolytic antifouling device of the present invention was applied to a tube plate in a water chamber of a heat exchanger having a titanium tube plate and tubes.

FIG. 4 shows an outline of the installation. The tube sheet surface 71 of the titanium heat exchanger 7 was polished with sandpaper to remove surface dirt. 260 g / LCo (NO as in Example 1)
_{3) 2} · 6H ₂ O solution was applied to the surface of the polishing titanium tube plate. Next, a heat activation treatment was performed using a gas burner. 40mm of SUS316 which becomes cathode 73 separately in water room 72
A φ × 300 mmL round bar 73 was installed insulated from the water chamber 72. The reference electrode is a seawater silver chloride electrode 32. The electric potential was set to 1.0 V (SCE conversion) on the titanium tube sheet surface 71 and electricity was supplied. No marine organisms were found to adhere to the tube sheet 71 in the heat exchanger 7 equipped with the present electrolytic antifouling device in the four months in summer. On the other hand, on the tube sheet 71 not installed, a large amount of hydro was attached, and considerable adhesion of barnacles was observed.

[0043]

As described above in detail, the electrolytic antifouling method of the present invention is environmentally friendly and has a long-term antifouling property for preventing marine organisms from adhering to structures in contact with seawater. In addition, construction and repair are easy.

The electrolytic antifouling method of the present invention is an antifouling method which suppresses the generation of toxic chlorine and contains oxygen by electrolysis as a main component, and replaces conventional noble metals or their noble metal oxide catalyst coatings. The use of inexpensive oxide catalysts and the ease of construction and repair were secured.

[Brief description of the drawings]

FIG. 1 shows the potentiostatic polarization characteristics of titanium, noble metal oxide-coated titanium, and cobalt oxide-coated titanium in seawater.

FIG. 2 is a diagram showing a constant potential energization test apparatus using sprayed titanium obtained by coating reinforced concrete with cobalt oxide as an anode.

FIG. 3 is a schematic view in which the present invention is applied to a part of a concrete wall surface of an actual intake channel, (a) is a perspective view, and (b) is a cross-sectional view thereof.

FIG. 4 is a schematic diagram in which the method of the present invention is applied to a titanium heat exchanger tube sheet.

[Explanation of symbols]

1; Cobalt oxide coated titanium sprayed concrete; 2; Iron plate (cathode); 3; Reference electrode (SCE); 4; Blank (reinforced concrete block); 5; Potentiostat (constant potential device); , 12. Titanium ribbon, 13; Titanium anchor bolt, 14; Cable, 15; PVC pipe, 2
0; rebar, 40; concrete intake channel, 41; concrete wall surface, 51; potentiostat, 61; seawater,
7; heat exchanger, 71; titanium tube sheet, 72; water chamber (rubber lining), 73; cathode (cathode), 74; cooling tube, 32; reference electrode, 52; potentiostat (constant potential DC power supply), 62; seawater.

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Takahiro Kajiyama 417-16 Nakaarai, Ageo City, Saitama

Claims (3)

[Claims] 1. A titanium spray coating is applied to a water-contacting surface of a concrete structure which comes into contact with seawater, or the water-contacting surface of the concrete structure is covered with a plate-like or thin plate-like titanium material and contains cobalt or manganese. Apply a solution or a mixture of these solutions with iridium,
It is transformed into a cobalt oxide or manganese oxide film by a heat activation treatment, and then the sprayed film or the titanium material is connected to a positive electrode of a DC power source to form an anode. A method for suppressing or preventing marine organisms from adhering to the sea surface of a concrete structure, characterized in that a current is applied at an appropriate potential. 2. An insulative paint is applied to a water-contact surface of a steel structure in contact with seawater, and titanium spraying is performed on the paint.
Or applying an insulating paint to the steel structure, covering the surface with a plate-like or thin plate-like titanium material, further applying a solution containing cobalt or manganese, or a solution obtained by mixing iridium with these solutions, and performing a heat activation treatment. To form a cobalt oxide or manganese oxide film, and then connect the sprayed film or the titanium material to a positive electrode of a DC power source to form an anode. A method for suppressing or preventing the adhesion of marine organisms in a steel structure, characterized by energizing. 3. A cobalt or manganese-containing solution or a solution obtained by mixing iridium with a solution containing cobalt or manganese, which is applied to a concrete structure or a steel structure covered with a titanium material or an outer surface of a titanium material of a titanium structure, The coated film is anodically excited or thermally activated by a flame or the like to transform it into a cobalt oxide or manganese oxide film, and then the titanium material is connected to a positive electrode of a DC power source to form an anode, and the anode is used to generate oxygen. A method of suppressing or preventing marine organisms from adhering to the sea surface on the outer surface of the titanium material by maintaining the electric potential within a potential and applying a current at a lower potential according to the chlorine generation limit potential.