KR20140145678A - Method for electrophoretic deposition of nano-ceramics for the photo-generated non-sacrificial cathodic corrosion protection of metal substrates and the metal substrate thereof - Google Patents

Abstract

The present invention provides a coating method to prevent corrosion of a metal substrate using electrophoretic deposition, and the coating method includes applying a voltage to apply nanoparticles on a metal substrate using electrophoretic deposition after a photo-generated corrosion prevention coating solution containing the nanoparticles to the metal substrate. According to the present invention, the nanoparticles are uniformly applied on a surface of the metal substrate using the electrophoretic deposition to effectively protect the metal substrate against corrosion through the photo-generated non-sacrificial cathodic corrosion prevention coating; thereby coating be quickly and easily be performed and mass production realized.

Description

[0001] The present invention relates to a photoactive non-sacrificial anode anticorrosion coating method for a metal substrate by electrophoresis, and a metal substrate produced by the method and an electrophoretic deposition of nano-ceramics for the photo- thereof}

The present invention relates to a method for coating nanoparticles on a metal substrate by electrophoresis, and more particularly to a photoactive non-sacrificial anodic corrosion-resistant coating method for a metal substrate and a metal substrate produced thereby.

Metal corrosion is caused by a chemical reaction of a metal or an alloy with a substance present in the environment. Various methods have been applied to prevent such corrosion. Specifically, chemical surface treatment, organic coating, inorganic coating, and metal coating are generally used to prevent metal corrosion.

However, when the coating is performed by the above-described method, the coating layer may be physically damaged due to various factors. In this case, in the case of general organic-inorganic coating, since the damaged region is electrochemically active, It begins to progress rapidly in the region.

Therefore, in order to overcome such a disadvantage, a method of coating a dissimilar metal on a metal to be protected is used. A representative example is a method of plating zinc with a high electrochemical activity to protect the ferrous metal. Zinc plating is a widely used method currently commercially available. In this case, even if the coating layer is damaged, the zinc coating layer having a high electrochemical activity is first corroded to provide electrons to the iron to protect the iron.

However, such a sacrificial anode method is also limited. Basically, this method has a limitation on the lifetime because the anode is first corroded to protect the dissimilar metal. In other words, after the zinc coating layer is consumed to some extent, the corrosion of the iron can not be accelerated.

Recently, a photoactive coating method has been introduced to overcome the disadvantages of the currently used coating methods (J. Yuan and S. Tsujikawa, J. Electrochem. Soc., 142, 3444 (1995), T. Imokawa The coating method can be carried out by applying a photoactive coating such as photocatalyst TiO ₂ on the surface of a metal to improve the performance of the metal. .

More specifically, it is well known that TiO ₂ can produce photoelectrons in the presence of sunlight. The photoelectrons generated in the TiO ₂ coating layer under sunlight are transferred to the metal to prevent electrochemical corrosion under conditions where the metal is corroded. This coating method is not the principle of preventing corrosion by sacrificing the TiO ₂ coating layer, so theoretically permanent corrosion prevention is possible.

However, TiO ₂ Et al. Have attempted to provide bipolar characteristics to the photoactive coating layer even at night when there is no sunlight, since the corrosion inhibition method using a photoactive coating is possible only during the daytime when sunlight is present. Tatsuma et al. Found that when WO ₃ is present with TiO ₂ , it can store electrons generated in the presence of sunlight and can suppress corrosion at night by emitting electrons at night without sunlight 13, 2830 (2001), T. Tatsuma, S. Saitoh, P. Nhaotrakanwiwat, Y. Ohko, A. Fujishima , Langmuir, 18, 7777 (2002))

Since then, it has been discovered that SnO ₂ , Cu ₂ O, MoO _3, etc. have a function to store and emit electrons (R. Subasri, T. Shinohara, Electrochem. Cell, 92, 348 (2008), Y. Takahashi, P. Ngaotrakanwiwat, T. Tatsuma, Electrochim.Acta, 49. Jansomanee, J. Bandara, , 2025 (2004))

However, WO ₃ is known to be most effective among various photoelectronic materials. Although a method for preventing corrosion of metals using such a photoactive coating layer has been widely known, a method for producing a substantially commercial coated steel sheet has not been studied much.

In view of the application of the metal coating, sol-gel coating method and vacuum deposition method are a typical photoactive ceramic coating method, but the sol-gel coating method is slow in sol-gel reaction, And is not particularly used for a metal coil coating process or the like. Vacuum deposition also requires that the material be placed in a vacuum environment for deposition, but it is difficult to apply such a vacuum process in a continuous metal coil coating process.

Therefore, recently, in order to solve such a problem, there is a demand for continuous research on a photoactive coating method capable of mass production.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a nanoparticle coating method and a nanoparticle coating method which enable uniform and easy coating of nanoparticles on a surface of a metal substrate by electrophoresis, To protect the metal substrate.

According to an embodiment of the present invention, there is provided a method of manufacturing a photoelectric conversion device, comprising the steps of: applying a photoactive anti-corrosion coating liquid containing nanoparticles to a metal substrate and then applying a voltage to the nanoparticle to coat the nanoparticles on the surface of the metal substrate by electrophoresis A method for coating a metal substrate with a corrosion inhibitor.

The photoactive anticorrosion coating liquid may contain,

Dispersing the photocatalyst nanoparticles in a solvent to form a solution in which the nanoparticles are dispersed;

Adding a charge additive to a solution in which the nanoparticles are dispersed to charge the nanoparticles; And

And a step of adding a binder to the charged nanoparticle-charged solution to form a photoactive anticorrosion coating liquid.

In the step of forming the solution in which the nanoparticles are dispersed, the photoelectrode storage nanoparticles may be further dispersed in the solvent together with the photocatalyst nanoparticles.

The photoactive anticorrosion coating liquid may contain 1 to 80 parts by weight of the photocatalyst nanoparticles, 1 to 20 parts by weight of the binder, and 0.000001 to 1 part by weight of the charge additive, based on 100 parts by weight of the solvent.

The photoactive anticorrosion coating liquid may further comprise 1 to 80 parts by weight of photoelectron-storing nanoparticles per 100 parts by weight of the solvent.

The photocatalyst nanoparticles may be selected from the group consisting of titanium oxide (TiO ₂ ), zinc oxide (ZnO ₂ ), zirconium oxide (ZrO ₂ ), barium titanate (BaTiO ₃ ), vanadium oxide (V ₂ O ₅ ), iron oxide ₂ O ₃ ), strontium titanate (SrTiO ₃ ), chromium oxide (Cr ₂ O ₃ ), cadmium sulfide (CdS), beryllium oxide (BeO), bismuth oxide (Bi ₂ O ₃ ) calcineurin Titanium oxide (CaO), cadmium oxide (CdO), cobalt oxide (Co ₃ O _4), go Solarium oxide (Ga ₂ O _3), gelreu Mani Titanium oxide (GeO _2), Im Stadium oxide (In ₂ O ₃₎ , manganese oxide (Mn ₃ O _4), nickel oxide (NiO), antimony oxide (Sb ₂ O _3), silicon oxide (SiO _2), strontium oxide (SrO), tantalum oxide (Ta ₂ O ₃₎ And yttrium oxide (Y ₂ O ₃ ).

The photoelectronic storage nanoparticles can be selected from the group consisting of tungsten oxide (WO ₃ ), tin oxide (SnO ₂ ), lanthanum oxide (La ₂ O ₃ ), copper oxide (Cu ₂ O), molybdenum oxide (MoO ₃ ), cerium oxide (CeO ₂ ), carbon nanotubes, and graphene.

The charging additive may be at least one selected from the group consisting of an acid, a base, an inorganic cation, an inorganic anion, an organic phosphorus compound, an organic sulfur compound, a carboxylate compound and a polymer electrolyte.

The binder may be an alkyd resin, a nitrocellulose, a dewaxed shellac, a polyvinyl butyral, a polyvinyl alcohol, an ethyl cellulose, a polyacrylate, Polyacrylamide, polysilicate, polyphosphate, polyborate, ionic epoxy resin, ionic acrylic ionic resin and ionic amino resin. amino resin).

The electrophoresis may be performed for 1 to 300 seconds by applying a voltage of 1 to 400V.

According to another embodiment of the present invention, there is provided a metal substrate which is coated with nanoparticles by electrophoresis on the surface of the metal substrate by the coating method.

The metal substrate may be at least one selected from the group consisting of a cold rolled steel plate, a galvanized steel plate, a galvanized electroplated steel plate, a hot dip galvanized steel plate, an aluminum coated steel plate, cobalt, molybdenum, tungsten, nickel, titanium, aluminum, manganese, Aluminum alloy plated steel sheet to which iron, manganese, titanium, zinc or a mixture thereof is added, a galvanized steel plate coated with phosphate, a chromium-treated steel plate, An inner fingerprint steel sheet, a rare earth surface treated steel sheet, a cold rolled steel sheet and a hot rolled steel sheet.

The present invention aims at effectively protecting a metal substrate from corrosion by a photoactive non-sacrificial anode anticorrosion coating formed by uniformly coating nanoparticles on a surface of a metal substrate by electrophoresis, and can easily and quickly perform the coating, Make mass production possible.

FIG. 1 is a conceptual diagram illustrating the application of the photoactive non-sacrificial anode anticorrosion coating method of a metal substrate by the electrophoresis method of the present invention to a mass production process.
FIG. 2 is a photograph of a surface of a metal specimen coated with a photoactive corrosion inhibiting coating solution according to an embodiment by electrophoresis.
FIG. 3 is a photomicrograph of a surface of a metal specimen coated with a photoactive corrosion inhibiting coating solution according to an embodiment by electrophoresis.
Fig. 4 is a graph showing corrosion inhibition effect due to photoactive non-sacrificial anodic corrosion coating by electrophoresis, according to an experimental example.
FIG. 5 schematically shows a process flow chart of a corrosion prevention coating method of a metal substrate by the electrophoresis method of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

According to an embodiment of the present invention, there is provided a method of manufacturing a photoelectric conversion device, comprising the steps of: applying a photoactive anti-corrosion coating liquid containing nanoparticles to a metal substrate and then applying a voltage to the nanoparticle to coat the nanoparticles on the surface of the metal substrate by electrophoresis A method for coating a metal substrate with a corrosion inhibitor.

In the coating step, the nanoparticles contained in the coating liquid are uniformly coated on the surface of the metal substrate by coating the surface of the metal substrate with the photoactive corrosion inhibiting coating liquid by electrophoresis, so that the quality of the coating layer Thereby effectively preventing corrosion of the metal substrate.

In the present invention, the type of the metal substrate to be coated for corrosion prevention is not particularly limited, but steel can be used as a metal so as to obtain a more preferable effect. At this time, it is preferable that the steel is produced in the form of a sheet or sheet like a steel sheet and coated on the surface thereof, but it can be coated even if the structure is complicated.

Examples of such steel sheets include cold-rolled steel sheets, galvanized steel sheets, galvanized electroplated steel sheets, hot-dip galvanized steel sheets, aluminum-coated steel sheets, cobalt, molybdenum, tungsten, nickel, titanium, aluminum, manganese, iron magnesium, Aluminum alloy plated steel sheet to which iron, manganese, titanium, zinc or a mixture thereof is added, a galvanized steel plate coated with phosphate, a chromium-treated steel plate, An inner fingerprint steel sheet, a rare earth surface treated steel sheet, a cold rolled steel sheet and a hot rolled steel sheet.

In the present invention, the photoactive anticorrosion coating liquid used for coating on the surface of the metal substrate for corrosion prevention may contain photocatalyst nanoparticles, and optionally photoelectron storage nanoparticles. In addition, a charge additive and a binder . ≪ / RTI >

The method of manufacturing the photoactive corrosion inhibiting coating liquid includes the steps of dispersing nanoparticles of a photocatalyst in a solvent to form a solution in which nanoparticles are dispersed, adding a charge additive to the solution in which the nanoparticles are dispersed, And a step of adding a binder to the solution in which the nanoparticles are charged, thereby forming a photoactive anti-corrosion coating solution.

However, in the coating method of the present invention, it is also possible to prepare a photoactive anti-corrosion coating solution by first adding a charge additive to a solvent rather than a photocatalytic nano-particle, adding a photocatalyst nanoparticle to the nanoparticle, and then adding a binder have.

In addition, in the step of forming the solution in which the nanoparticles are dispersed, the photoelectron-storing nanoparticles may be further dispersed in the solvent together with the photocatalyst nanoparticles. The present invention can protect the metal substrate from corrosion at any time during the day when sunlight exists and during the night when there is no sunlight by coating the photocatalyst nanoparticles and photoelectron storage nanoparticles together. Further, according to the electrophoresis method of the present invention, the two nanoparticles can be uniformly coated on the surface of the metal substrate.

The photoactive anticorrosion coating liquid may contain 1 to 80 parts by weight of photo-catalyst nanoparticles, 1 to 20 parts by weight of a binder, and 0.000001 to 1 part by weight of a charge additive, based on 100 parts by weight of the solvent. 1 to 80 parts by weight of particles may be further included. At this time, the effect obtained by adding the photoelectric storage nanoparticles is as described above.

In the present invention, prior to the coating step, the nanoparticles contained in the coating liquid are uniformly dispersed by performing ultrasonic dispersion or milling on the photoactive corrosion inhibiting coating liquid, Thereby ensuring a high quality coating layer.

In the present invention, the photocatalyst nanoparticles included in the photoactive coating liquid include titanium oxide (TiO ₂ ), zinc oxide (ZnO ₂ ), zirconium oxide (ZrO ₂ ), barium titanate (BaTiO ₃ ), vanadium oxide ₂ O ₅ ), iron oxide (Fe ₂ O ₃ ), strontium titanate (SrTiO ₃ ), chromium oxide (Cr ₂ O ₃ ), cat sulphide (CdS), beryllium oxide (Bi ₂ O ₃ ), calcium oxide (CaO), cadmium oxide (CdO), cobalt oxide (Co ₃ O ₄ ), gallium oxide (Ga ₂ O ₃ ), germanium oxide (GeO ₂ ) (Mn ₂ O ₃ ), manganese oxide (Mn ₃ O ₄ ), nickel oxide (NiO), antimony oxide (Sb ₂ O ₃ ), silicon oxide (SiO ₂ ), strontium oxide (SrO) , Tantalum oxide (Ta ₂ O ₃ ), and tritium oxide (Y ₂ O ₃ ).

In addition, the optical light electronic storage nanoparticles contained in the active coating of the present invention are tungsten oxide (WO _3), tin oxide (SnO _2), lanthanum oxide (La ₂ O _3), copper oxide (Cu ₂ O), mol And may be at least one selected from the group consisting of rubidium oxide (MoO ₃ ), cerium oxide (CeO ₂ ), carbon nanotubes and graphene. However, it is most preferable to use tungsten oxide (WO ₃ ) because it most effectively stores electrons.

The type of the solvent contained in the photoactive coating liquid of the present invention is not particularly limited, and it is preferable to select the solvent in consideration of the viscosity and the dielectric constant in accordance with the characteristics of the nanoparticles to be dispersed.

Representative examples of the solvent include at least one selected from the group consisting of water, an aliphatic or aromatic hydrocarbon solvent, a halogen-containing hydrocarbon solvent, and an oxygen-containing hydrocarbon solvent.

The aliphatic or aromatic hydrocarbon solvent may be pentane, cyclopentane, hexane, cyclohexane, benzene, toluene, or a mixture thereof. Halogen , Chloroform, dichloromethane, or a mixture thereof may be used as the hydrocarbon-based solvent.

Examples of the hydrocarbon-based solvent containing oxygen include alcohols, ketones, and esters. Specific examples thereof include tetrahydrofuran, ethyl acetate, acetone, dimethylformamide But are not limited to, dimethylformamide, acetonitrile, formic acid, n-butanol, nitromethane, methanol, ethanol, isopropyl alcohol, And pentanol may be used.

The photoactive coating liquid of the present invention includes a charge additive. The charge additive is used for electrifying nanoparticles in order to perform electrophoresis for coating on the surface of a metal substrate. It is preferable to precisely control the kind and content of the charge additive.

The charging additive may be at least one selected from the group consisting of an acid, a base, an inorganic cation, an anion, an organic phosphorus compound, an organic sulfur compound, a carboxylate compound, and a polymer electrolyte, and the acid may be at least one selected from the group consisting of hydrochloric acid, nitric acid, ≪ / RTI >

Further, the base used as the charge additive may be at least one selected from the group consisting of sodium hydroxide, potassium hydroxide and ammonium hydroxide.

In addition, the organic cations used in the antistatic additive is a magnesium cation (Mg ^{2 +),} calcium cations (Ca ^{2 +),} the aluminum cation (Al ^{3 +),} barium cations (Ba ^{2 +),} strontium cations (Sr ^{2 +} ), A potassium cation (K ⁺ ), a sodium cation (Na ⁺ ), and a lithium cation (Li ⁺ ).

Examples of the inorganic anion used as the charge additive include iodide ion (I ^- ), cyanide ion (CN ^- ), hypochloride ion (ClO ^- ), permanganate ion (MnO ₄ ^{2 -} ), carbonate ion ₃ ^{2 -} ) and a chromate ion (CrO ₄ ^{2 -} ).

Examples of the organic phosphorus compound include phosphorus ester, phosphoric acid amide, phosphonic acid, phosphinic acid, phosphonic ester, phosphinic ester, ), Phosphonium salts, and phosphorane.

The organic sulfur compound may be selected from the group consisting of thiol, sulfide, sulfoxide, sulfur halide, thiocarboxylic acid, thioamide, sulfonic acid, sulfinic acid, And may be at least one selected from the group consisting of sulfinic acid, sulfonic ester, sulfinic ester, sulfonium salt and sulfonium ylide.

Also, the carboxylate compound may be selected from the group consisting of sodium stearate, sodium oleate, sodium linoleate, sodium linolenate, and sodium ricinoleate. ≪ / RTI >

Also, the polymer electrolyte is preferably polyethyleneimine (poly (ethyleneimine)), poly (diallyldimethylammonium chloride), or a mixture thereof.

The binder contained in the optically active coating liquid of the present invention is an oil or an inorganic polymer material having charge, and the kind thereof is not particularly limited, but it is preferable to suitably select the kind in consideration of the characteristics of the solvent to be used.

Examples of the usable type include a nonionic resin, an ionic resin, a cured resin, or a mixture thereof. Specific examples thereof include an alkyd resin, a nitrocellulose, a dewaxed shellac, Polyvinyl butyral, polyvinyl alcohol, ethyl cellulose, polyacrylamide, polysilicate, polyphosphate, polyborate, polyacrylate, An ionic epoxy resin, an ionic acrylic ionic resin, and an ionic amino resin. The ionic epoxy resin is preferably selected from the group consisting of an ionic epoxy resin, an ionic acrylic ionic resin and an ionic amino resin.

In order to prevent the nanoparticles coated on the surface of the metal substrate from being deteriorated in optical activity and photoelectron storage ability, the binder is preferably kept at 50 wt% or less relative to the nanoparticles.

As described above, the coating for preventing corrosion on the surface of the metal substrate is performed by electrophoresis. In the electrophoresis, electrochemically stable electrodes such as stainless steel, carbon electrode, It is preferable to use a substance.

In the present invention, the electrophoresis method is preferably performed by applying a voltage of 1 to 400 V, and is preferably performed for 1 to 300 seconds. If the working time is less than 1 second, the coating layer may not be properly formed on the surface of the metal substrate, and the effect of preventing corrosion may be deteriorated. If the working time exceeds 300 seconds, the physical properties of the particles constituting the coating layer may be adversely affected. .

In the present invention, it is possible to carry out the step of drying the metal substrate coated with the nanoparticles subsequently to the coating step, and the drying temperature is 20 to 200 ° C and the relative humidity is more than 0 to 30% desirable.

The photoactive coating liquid used in the present invention includes photocatalyst nanoparticles as well as photoelectron storage nanoparticles so that the photocatalytic coating layer can be imparted with a bipolar characteristic even at night without sunlight. In addition, photoelectrons are formed in the coating layer formed on the surface of the metal substrate using the photoactive coating liquid, and the photoelectrons are transferred to the metal to prevent the photoelectrons from being electrochemically corroded under the corrosive conditions. Therefore, This is a non-sacrificial bipolar approach because it is not a principle to prevent. That is, the coating method of the present invention can be viewed as a photoactive, a non-sacrificial bipolar method.

FIG. 1 is a conceptual diagram of a photoactive non-sacrificial anode anticorrosion coating method of a metal substrate according to the electrophoretic method of the present invention applied to a mass production process, specifically, a steel sheet rolled by a roll 101 The nanoparticles 201 charged through the cathode roll 102 in the electrophoresis apparatus are passed through the coating solution formed by dissolving in the organic solvent 202 and are allowed to interact with the anode bar 103 Accordingly, the nanoparticles are uniformly coated on the surface of the rolled steel sheet, and then dried in the drying device 104 to produce a corrosion-resistant coated metal substrate.

As shown in FIG. 1, the surface of a metal substrate can be rapidly coated with a simple method to prevent corrosion, and since the nanoparticles uniformly form a coating layer, the effect of preventing corrosion is excellent, .

FIG. 5 is a flow chart showing the process of the anti-corrosion coating method of a metal substrate according to the electrophoresis method of the present invention. Referring to FIG. 5, the photocatalyst nanoparticles are dispersed in an organic solvent (S100) The nanoparticles are dispersed in a solvent (S110) to form a solution, and the binder material is added to a solution in which the nanoparticles are dispersed (S120). Then, a charge additive is further added to the solution to charge the nanoparticles (S130) Next, the metal surface is coated by electrophoresis (S140) by applying a voltage in a state where the metal substrate is immersed in a solution (S140), and the coated metal substrate is dried at a room temperature or a high temperature condition (S150).

According to another embodiment of the present invention, there is provided a metal substrate which is coated with nanoparticles by electrophoresis on the surface of the metal substrate by the coating method.

The metal substrate may be at least one selected from the group consisting of a cold rolled steel plate, a galvanized steel plate, a galvanized electroplated steel plate, a hot dip galvanized steel plate, an aluminum coated steel plate, cobalt, molybdenum, tungsten, nickel, titanium, aluminum, manganese, Aluminum alloy plated steel sheet to which iron, manganese, titanium, zinc or a mixture thereof is added, a galvanized steel plate coated with phosphate, a chromium-treated steel plate, An inner fingerprint steel sheet, a rare earth surface treated steel sheet, a cold rolled steel sheet and a hot rolled steel sheet.

Hereinafter, the present invention will be described more specifically by way of specific examples. The following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

[Example 1]

TiO ₂ was used as a photocatalyst nanoparticle, and the nanoparticles were dried at a temperature of about 60 ° C. for one day to remove moisture.

Phosphoric acid dibutyl ester as a charge additive of about 0.01 M was added to about 300 g of isopropyl alcohol as a solvent and stirred for about 30 minutes. 10 g of the dried TiO ₂ nanoparticles were added to the prepared solution, For dispersion, ultrasonic dispersion was performed for 1 hour using a 700 Watt ultrasonic disperser.

To improve the adhesion of the coating layer, about 3 g of polyvinyl butyral was added as a binder material. The coating solution was stabilized by stirring for 1 day.

In order to prevent corrosion, a stainless steel specimen to be coated was placed on a negative electrode, a counter electrode was placed on an anode, and a voltage of about 30 V was applied with a specimen interval of about 15 mm. The total voltage was applied for 1 minute, and the coated specimen was dried in a 60 ° C oven for 1 hour.

Thereafter, a photograph of the surface of the metal specimen is shown in Fig. 2 (a) for the sake of confirming the uniformity of the surface coating layer of the dried specimen, and a photograph of the coating layer observed by the electron microscope for more precise examination is shown in Fig. 3 ).

At this time, the phosphoric acid dibutyl ester was a product of Tokyo Chemical Industry, the TiO ₂ nanoparticles were Degussa P-25 (Evonik Industries), and the particle size was about 25 nm.

[Example 2]

TiO ₂ as the photocatalyst nanoparticles and WO ₃ as the photoelectron-stored nanoparticles were dried under the same conditions as in Example 1, and then mixed so that the content of TiO ₂ was 80 wt% and the content of WO ₃ was 20 wt% This was dispersed by adding about 10 g to the solution containing the charge additive as in Example 1.

The rest of the configuration except for the process for forming the metal specimen coating and the kind of the nanoparticles is the same as in Example 1. In order to confirm the uniformity of the surface coating layer of the metal specimen, the surface photograph thereof is shown in FIG. 2 (b) FIG. 3 (b) shows a photograph of the coating layer observed with an electron microscope for the purpose of review.

The WO ₃ nanoparticles were Ditto technology Co., Ltd., and the particle size was about 90 nm.

[Example 3]

The surface of the metal specimen was coated under the same conditions as in Example 2 except that the nanoparticles contained in the electrophoresis coating solution were compounded such that the content of TiO ₂ was 60 wt% and the content of WO ₃ was 40 wt% .

A photograph of the surface of the metal specimen is shown in FIG. 2 (c), and a photograph of the coating layer observed by the electron microscope is shown in FIG. 3 (c).

[Example 4]

The surface of the metal specimen was coated under the same conditions as in Example 2 except that the nanoparticles contained in the electrophoresis coating solution were blended so that the content of TiO ₂ was 40 wt% and the content of WO ₃ was 60 wt% .

A photograph of the surface of the metal specimen is shown in FIG. 2 (d), and a photograph of the coating layer observed by the electron microscope is shown in FIG. 3 (d).

FIG. 2 is a photograph of a surface of a metal specimen coated with the photoactive corrosion inhibiting coating solution of the present invention by electrophoresis. From (a) to (d) according to Examples 1 to 4, The particles were uniformly coated on the surface of the metal specimen.

3 is a photograph of a surface of a metal specimen coated with the photoactive corrosion inhibiting coating solution of the present invention by an electrophoretic observation with an electron microscope. Fig. 3 shows (a) to (d In the case of (b) to (d), TiO ₂ and WO ₃ nanoparticles were coated as a composite, but homogeneous particles were not uniformly clumped together As a result, it was confirmed that the particles were coated on the steel sheet.

[Experimental Examples 1 to 4]

When the coated metal specimens of Examples 1 to 4 were immersed in an aqueous solution of 3.5 wt.% NaCl and irradiated with light in the UV region, which is a kind of solar light source, the electrochemical potential changes of the metal specimens were measured, Respectively.

4 (a) is a graph showing a graph of an experiment using a metal specimen coated with a coating solution having a TiO ₂ content of 100% in Example 1, and (b) TiO ₂ content of 80% and WO ₃ content of 20%, (c) TiO ₂ content of 60% and WO ₃ content of 40% in Example 3, (d) TiO ₂ content of 40% And a WO ₃ content of 60%. The graph of FIG.

Referring to FIG. 4, when the metal specimen is irradiated with UV, the electrochemical potential is lowered to about -0.7 V compared to the reference electrode. This indicates that the photoelectrons are transferred from the coating layer to the metal at a lower value than the corrosion voltage of the stainless steel used as the substrate.

Thereafter, when the UV light irradiation is stopped, that is, in the graph of FIG. 3A, it can be seen that the electrochemical potential of the coated metal specimen returns to -0.2 V, which is the corrosion voltage at -0.7 V. When the electrochemical potential of the coated metal specimen reaches -0.2 V, the metal can not be protected from corrosion because the metal does not receive electrons from the coating layer.

However, when the WO ₃ particles are complexed as in Examples 2 to 4, that is, the graphs (b) to (d) show that the potential is restored at a slower speed and can be protected from corrosion for a longer period of time. This is because when the generated photoelectron is stored in WO ₃ and the UV light is stopped, the photoelectron is slowly transferred to the metal to protect the metal from corrosion.

Applying this principle, it can be seen that metals can be protected from corrosion at any time during the day when there is sunlight and when there is no sunlight.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

Claims (12)

Applying a photoactive corrosion inhibiting coating liquid containing nanoparticles to a metal substrate, and applying a voltage to the nanoparticles to coat the nanoparticles on the surface of the metal substrate by electrophoresis.
The photoactive anticorrosion coating liquid according to claim 1,
Dispersing the photocatalyst nanoparticles in a solvent to form a solution in which the nanoparticles are dispersed;
Adding a charge additive to a solution in which the nanoparticles are dispersed to charge the nanoparticles; And
And a step of adding a binder to the nanoparticle-charged solution to form a photoactive anti-corrosion coating liquid.
[3] The method of claim 2, wherein the forming of the nanoparticle-dispersed solution comprises dispersing photo-electron-storing nanoparticles together with the photocatalyst nanoparticles in a solvent. Way.
The photoactive anti-corrosion coating liquid according to claim 2, wherein the photoactive corrosion inhibiting coating liquid is prepared by an electrophoresis method comprising 1 to 80 parts by weight of photocatalyst nanoparticles, 1 to 20 parts by weight of a binder, and 0.000001 to 1 part by weight of a charge additive, A method of coating corrosion resistant metal substrates.
5. The method of claim 4, wherein the photoactive corrosion inhibiting coating liquid further comprises 1 to 80 parts by weight of photoelectron storage nanoparticles per 100 parts by weight of the solvent.
The photocatalyst nanoparticle of claim 2, wherein the photocatalyst nanoparticles are selected from the group consisting of TiO ₂ , ZnO ₂ , ZrO ₂ , BaTiO ₃ , V ₂ O _5, ), Iron oxide (Fe ₂ O ₃ ), strontium titanate (SrTiO ₃ ), chromium oxide (Cr ₂ O ₃ ), cadmium sulfide (CdS), beryllium oxide (BeO), bismuth oxide Bi ₂ O _3), calcineurin Titanium oxide (CaO), cadmium oxide (CdO), cobalt oxide (Co ₃ O _4), go Solarium oxide (Ga ₂ O _3), gelreu Mani Titanium oxide (GeO _2), Im Stadium oxide (In ₂ O _3), manganese oxide (Mn ₃ O _4), nickel oxide (NiO), antimony oxide (Sb ₂ O _3), silicon oxide (SiO _2), strontium oxide (SrO), tantalum oxide (Ta ₂ O ₃ ) and yttrium oxide (Y ₂ O ₃ ). / RTI >
The method of claim 3, wherein the photoelectron storage nanoparticles are selected from the group consisting of tungsten oxide (WO ₃ ), tin oxide (SnO ₂ ), lanthanum oxide (La ₂ O ₃ ), copper oxide (Cu ₂ O), molybdenum oxide ₃ ), cerium oxide (CeO ₂ ), carbon nanotubes, and graphene.
The electrophotographic method according to claim 2, wherein the charge additive is at least one selected from the group consisting of an acid, a base, an inorganic cation, an inorganic anion, an organic phosphorus compound, an organic sulfur compound, a carboxylate compound, / RTI >
The method of claim 2, wherein the binder is selected from the group consisting of alkyd resin, nitrocellulose, dewaxed shellac, polyvinyl butyral, polyvinyl alcohol, ethylcellulose but are not limited to, ethyl cellulose, polyacrylamide, polysilicate, polyphosphate, polyborate, ionic epoxy resin, ionic acrylic ionic resin, Ionic amino resin. ≪ RTI ID = 0.0 > 11. < / RTI >
The method of claim 1, wherein the electrophoresis method is performed by applying a voltage of 1 to 400 V for 1 to 300 seconds.
A metal substrate which is coated with nanoparticles by electrophoresis on the surface of the metal substrate by the coating method according to any one of claims 1 to 10.
The metal substrate according to claim 11, wherein the metal substrate is at least one selected from the group consisting of a cold-rolled steel sheet, a galvanized steel sheet, a galvanized electroplated steel sheet, a hot-dip galvanized steel sheet, an aluminum-coated steel sheet, cobalt, molybdenum, tungsten, nickel, Coated steel sheet having a plating layer containing an impurity or a dissimilar metal, which is a copper or a mixture thereof, silicon, copper magnesium, iron, manganese, titanium, zinc or an aluminum alloy plated steel sheet to which a mixture thereof is added, A metal substrate coated with an anti-corrosive coating by electrophoresis, the at least one member selected from the group consisting of a steel sheet, a chromium-treated steel sheet, an inner fingerprint steel sheet, a rare earth surface-treated steel sheet, a cold rolled steel sheet and a hot rolled steel sheet.

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