KR100545384B1 - Underwater Ceramic Coating Corrosion Inhibitor and Underwater Corrosion Prevention Method - Google Patents

Abstract

The present invention relates to an underwater ceramic coating corrosion inhibitor and a method for preventing corrosion in water using the same. More specifically, the underwater ceramic coating, which is completely bonded and cured in water, includes a polymer resin, a ceramic filler, and a metal having a higher ionization degree than iron. As a corrosion inhibitor, it has a high bonding strength with steel structures (metal and concrete), does not decompose in water such as seawater and river water, and is a low-viscosity corrosion inhibitor excellent in chemical resistance and anti-adhesion ability of aquatic organisms such as fish and shellfish. By using automatic air brushes, brushes, rollers, HERA, or underwater corrosion prevention methods using tapes impregnated with the above-mentioned ceramic coating corrosion inhibitor, cylindrical piles, sheet (U) piles, H-shaped piles as well as polygons and irregularities, Corrosion barrier in water even for complex shaped underwater structures made of flanges Can easily perform the operation, and relates to an underwater anti-corrosion method is superior to using lower maintenance costs underwater ceramic coating it with preservatives and durability of the underwater structure.

Underwater Structure, Underwater Corrosion Protection, Full Underwater Curing, Underwater Ceramic Coating, Anti Corrosion Tape

Description

Ceramic coating anticorrosive agent for underwater use and a anticorrosion method used by the agent

The present invention relates to an underwater ceramic coating corrosion inhibitor and a method for preventing corrosion in water using the same. More specifically, the underwater ceramic coating, which is completely bonded and cured in water, includes a polymer resin, a ceramic filler, and a metal having a higher ionization degree than iron. As a corrosion inhibitor, it has a high bonding strength with steel structures (metal and concrete), does not decompose in water such as seawater and river water, and is a low-viscosity corrosion inhibitor excellent in chemical resistance and anti-adhesion ability of aquatic organisms such as fish and shellfish. By using automatic air brushes, brushes, rollers, HERA, or underwater corrosion prevention methods using tapes impregnated with the above-mentioned ceramic coating corrosion inhibitor, cylindrical piles, sheet (U) piles, H-shaped piles as well as polygons and irregularities, Corrosion barrier in water even for complex shaped underwater structures made of flanges Can easily perform the operation, and relates to an underwater anti-corrosion method is superior to using lower maintenance costs underwater ceramic coating it with preservatives and durability of the underwater structure.

In general, steel structures can be divided into onshore and underwater structures. In these structures, the corrosion prevention process to prevent corrosion is very important since it is directly connected to the life of the machine and the entire plant. On the other hand, in the case of underwater structures, anti-corrosion treatment is very difficult.

In particular, most of the marine structures (gas or oil drilling structures) installed on the sea, and the structures of ship construction equipment, which are installed on the sea, are mostly made of steel or concrete, and are submerged in the sea or splashed by waves. Structures such as iii) will be corroded very quickly by moisture, salt or oxygen, which will shorten the life of the structure.

Therefore, in the installation of offshore structures, in order to prevent corrosion of sea erosion parts or splashes, the preservatives are coated on land and then assembled and constructed at sea. As a result of this problem may occur, a method of assembling and installing the structure first at sea as a solution thereof, and coating the underwater corrosion inhibitor on the installed structure is used. However, in order to coat the corrosion inhibitor underwater when the structure is installed at sea, the structure must be in the water. Therefore, the work process is difficult and if the existing corrosion prevention method is used, it should be repaired periodically because of its short life. By doing so, there is a lot of inconvenience and cost.

As such, the conventional methods used to prevent underwater corrosion of marine structures or steel pipe piles include electric corrosion prevention method using electricity, corrosion inhibitor coating method using film, tape and reinforced plastic FRP protective cover, and the like. The method used is generally widely used, and each corrosion prevention method can be classified as follows.

First, the electrocorrosion method is to delay the corrosion by installing a sacrificial anode such as aluminum (Al), magnesium (Mg), zinc (Zn) in the steel structure and causing the sacrificial anode to corrode faster than the steel structure due to the potential difference between the two metals. There is a method of delaying corrosion by controlling the potential of steel structure by applying electricity at random, but the former method is difficult to install in a narrow place because the anode volume is large because the effect can be seen long after attaching many sacrificial anodes. It requires experience in construction, and there is a lot of loss of labor cost, working time, etc. when working in actual water, and the latter method requires professional maintenance personnel, and there is an uneconomical disadvantage due to continuous electricity charges.

In addition, an epoxy method, a ceramic method, or the like are used as a method for applying a corrosion inhibitor using a coating. The epoxy method is a medium anticorrosive paint composed of a main material and a hardener composed of an organic material, and is generally used widely because of its low cost and easy construction, but it is weak in durability, weak in adhesion to steel structures, and difficult to prevent corrosion in water. have. In addition, the ceramic method has excellent durability, and is unlikely to cause cracks due to similar thermal expansion coefficients to steel structures. However, since the initial investment is excessive and requires skilled work, the work time increases and labor costs increase. Since this is impossible, there is a problem that the ceramic coated portion may be damaged during the transport and piercing operation on the land, thereby further causing corrosion of the steel structure (Korea Patent Publication No. 2003-0051114).

In addition, the method using tape and reinforced plastic protective cover has the advantage that the corrosion protection work is possible by winding the tape impregnated with the anticorrosive liquid on the paste on the structure and fixing the FRP protective cover, which is the reinforced plastic material, with bolts. . The anti-corrosion solution of the paste consists of a compound containing petrochemical-based petrochemicals, tannic acid, inert silica, and special anti-rust inhibitors.These components are not volatilized and hardened. This prevents the corrosion of metals by blocking the contact of water, air, and electrolytes with metal surfaces, and the protective cover should serve to protect the tape against physical shocks from waves and floats. Due to physical shocks such as waves, the flange portion of the protective cover peels off and falls off, thereby preventing the protection of the petrolatum tape. In addition, after a long time, the corrosion occurs in the bolt part, and the flooding begins at the seat panel seam. The tape impregnated with the anti-corrosion solution loses its anti-corrosion function as the anti-corrosion solution flows under the influence of water temperature. Since the cover must be manufactured in advance, there is a problem that it is difficult to apply to a complex shape structure consisting of a non-cylindrical sheet (U) pile, square, H-shaped pile, irregularities, flanges.

In addition, the method of preventing the corrosion of marine structures by modifying the tape and reinforced plastic protective cover method by applying the organic polymer and the ceramic filler to the structure by applying the anticorrosive composition to one side using a reinforcement sheet or glass tape, etc. (Korean Patent No. 10-0369626) has been presented, but there is a problem that it is difficult to use industrially due to the disadvantage that the adhesive strength of the underwater structure and the tape coated with the anticorrosive composition is lowered, thereby lowering durability and corrosion protection ability. Patent 10-0369626).

Accordingly, the present inventors have studied to solve the above problems, and as a result, an underwater ceramic coating corrosion inhibitor and an underwater ceramic coating corrosion inhibitor which are completely cured in water containing a polymer resin, a ceramic filler, and a metal having a higher ionization degree than iron, By applying automatic airbrush, brush, roller and hera or by applying tape impregnated with the above-mentioned ceramic coating corrosion inhibitor, it is possible to easily perform corrosion protection in water while preventing the corrosion effect and physical impact. It was found that the durability of the underwater coating film can be obtained to complete the present invention.

Accordingly, the present invention relates to an underwater ceramic coating corrosion inhibitor and an underwater corrosion prevention method using the same, and more particularly, a ceramic coating corrosion inhibitor that is completely cured in water containing a polymer resin, a ceramic filler, and a metal having a higher ionization degree than iron. It has high bonding strength with steel structure (metal, concrete), does not decompose in water such as seawater and river water, and is a low-viscosity corrosion inhibitor with excellent chemical resistance and anti-adhesion ability of aquatic organisms such as fish and shellfish. By using airbrush, brush, roller, hera or tape impregnated with the above-mentioned ceramic coating corrosion inhibitor, underwater corrosion prevention method is used for polygonal pile, sheet (U) pile, H type pile as well as polygons, irregularities, flanges. Corrosion protection in water, even in complex shaped underwater structures It is an object of the present invention to provide an underwater ceramic coating corrosion inhibitor and an underwater corrosion prevention method using the same, which can be easily performed and have excellent durability to reduce maintenance cost of an underwater structure.

The present invention is a polyvinylidene fluoride resin (polyvinylidene fluoride) resin and any one selected from the polymer resin 27.5 to 45% by weight; Ceramic fillers 27.5 to 45 weight percent; And 15 to 28 wt% of a metal having an ionization degree greater than iron (Fe), and 25 to 50 wt% of an acid anhydride; Aliphatic polyamine 20 to 45 wt%; Dicyandiamide 20-28 wt%; And an underwater curing composition comprising 5 to 15 wt% of titanium white, wherein the ceramic coating composition and the underwater curing composition comprise an aqueous ceramic coating corrosion inhibitor having a weight ratio of 4.5: 1 to 11: 1. do.

In addition, the present invention is to prepare a ceramic coating composition by (i) stirring the components of the ceramic coating composition at 60 ~ 90 ℃ for 60 ~ 180 minutes, (ii) the components of the cured composition in water at 5 ~ 50 ℃ Preparing an underwater curing composition by stirring for 90 minutes, and (iii) mixing the ceramic coating composition and the underwater curing composition in a ratio of 4.5: 1 to 11: 1 and stirring for 3 to 30 minutes. It provides a method for producing a coating corrosion inhibitor.

The present invention will be described in more detail as follows.

Underwater corrosion inhibitor of the present invention preferably comprises a ceramic coating composition and an aqueous curing composition in a ratio of 4.5: 1 to 11: 1, more preferably 5.5: 1 to 9.5: 1. If the ceramic coating composition is included below the above range, there is a problem in that the water-curable adhesion is not possible and the tape is loosened. If the ceramic coating composition exceeds the above range, the adhesive force decreases and the uncured composition is leaked to the water surface. There is a problem that the milk component floats.

The polymer resin of the ceramic coating composition of the present invention serves as a support for immobilizing the ceramic component in the resin, and it is possible to use a PVDF resin or a glycidyl ether type epoxy resin. PVDF resins having highly corrosive properties and imparting water repellency of the underwater coating film, ie vinylidene containing at least 50% by weight of vinylidene fluoride homopolymer or vinylidene fluoride and at least one other monomer copolymerizable with vinylidene fluoride It is to use a fluoride copolymer. The polymer resin preferably contains 27.5 to 45% by weight, more preferably 30 to 40% by weight of the ceramic coating composition. In the case of exceeding the above-mentioned range, the ceramic content is small, so that the properties as an anti-sticking agent necessary for the prevention of adhesion of durability, fish and shellfish, etc. are weakened; Problems with blocking moisture from

In addition, the ceramic filler of the ceramic coating composition improves the durability and impact resistance of the underwater coating film, and serves to reduce the adhesion of aquatic organisms such as fish and shellfish, and mixes one or more of alumina, calcium carbonate, magnesium silicate (talc) and calcium silicate. It can be used, it is preferable to include 27.5 to 45% by weight in the ceramic coating composition. If it exceeds the above range there is a problem that the chemical resistance and flame resistance is reduced, if less than the above range there is a problem that the tensile strength and peeling phenomenon of the underwater coating film occurs. In addition, the alumina is preferably included in the ceramic coating composition 9 to 19% by weight, there is a problem that the impact resistance is weakened outside the above range. In addition, it is preferable to include 7 wt% to 13 wt% of calcium carbonate in the ceramic coating composition. If the above range is exceeded, the coating layer is degraded in the water, and if it is less than the above range, oxidation and adhesion may be deteriorated. In addition, the magnesium silicate in the ceramic coating composition is preferably included 4 to 11% by weight, if it exceeds the above range, the viscosity of the ceramic coating composition rises to a semi-solid state, the coating is difficult, if less than the above range dispersion There is a problem that the precipitation is reduced and precipitation occurs. In addition, the calcium silicate in the ceramic coating composition is preferably included 2 to 8% by weight, if the range is exceeded, there is a problem that the durability of the underwater coating film is weakened and the adhesion to the underwater structure is lowered, if less than the above range There is a problem in that the ability to inhibit microbial adhesion is reduced.

In addition, the particle size of the ceramic filler is preferably a fine powder of 0.02 ~ 5 ㎛. If the particles are larger than the above range, it is difficult to uniformly disperse the ceramic in the resin, and a larger amount of ceramic is required, which causes a problem that the underwater coating film does not sufficiently block moisture, and the particles become smaller than the above range. There is no difference in effect, but the cost of producing fine powder is excessive.

In addition, a metal having a higher ionization degree than iron (Fe) of the ceramic coating composition may be a metal or an alloy such as aluminum (Al), magnesium (Mg), zinc (Zn), and preferably zinc (Zn). The metal having a higher ionization degree than iron (Fe) acts as an erosion and corrosion inhibitor, and because the corrosion inhibitor coating of the present invention prevents the steel structure from contacting water, salt, and oxygen, rather than attaching the sacrificial anode to the steel structure. Only a much smaller amount of metal is used but it is possible to obtain a sufficient corrosion protection effect. Metals having a higher ionization degree than iron include 15 to 28% by weight, more preferably 20 to 28% by weight, in the ceramic coating composition. If the above-mentioned range is exceeded, it is difficult to cure underwater and the coating layer is not evenly formed on the underwater structure. There is a problem of agglomeration, and if present below the above range, there is a problem of cracking and peeling of the coating layer in water. In addition, the zinc particle size is preferably 0.1 ~ 10 ㎛ fine powder. When the particles are larger than the above range, the metal particles are hardly uniformly dispersed in the resin, and a larger amount of the metal particles are required, and when the particles are smaller than the above range, there is no difference in effect, but the fine powder manufacturing cost This takes an excessive amount.

In addition, for the production of the ceramic coating composition, additives such as sedimentation inhibitors, surfactants, microbial inhibitors, wetting agents, wax additives, and dyes which are commonly used in the production of paints and pigments can be used. In the ceramic coating composition of the present invention, it is possible to use Benton, polyolefin, etc. as a sedimentation inhibitor, and the content thereof is preferably 1.3 to 3.5 wt% in the ceramic coating composition. In addition, it is preferable to use polyethylene glycol, glycerin fatty acid ester, etc. as a surfactant, and it is preferable to contain 0.5-2 weight%, More preferably, 0.5-1 weight% in a ceramic coating composition. In addition, it is possible to use thymol, sorbic acid, and the like as the microbial inhibitor, and it is preferable to include 0.2 to 0.7 wt% in the ceramic coating composition.

As the acid anhydride of the cured composition of the present invention, methylnanick (MNA), hexahydro (HHPA), or the like can be used as the curing agent, and methylnanick is preferably used. The acid anhydride is preferably included 25 to 50% by weight in the curing composition in water. In the case of exceeding the above range, there is a problem in that peeling phenomenon occurs, and in the case below the above range, there is a problem in that curing is not performed and adhesion strength is weakened.

In addition, as the aliphatic polyamine of the curing composition in water, it is possible to use diethylene triamine, triethylene tetraamine, methane diamine, and the like. It is to use an amine. The aliphatic polyamine is preferably included in the curing composition in water 20 to 45% by weight, if it exceeds the above range, there is a problem that the adhesion strength to the aquatic structure is lowered, if it is less than the above range, the curing time is long, the low-temperature curing ability is lowered There is a problem.

In addition, dicyandiamide of the curing composition in water is preferably used as a curing accelerator and contains 20 to 28 wt% in the curing composition in water. If it exceeds the above range there is a problem that the low-temperature curing ability is lowered, if less than the above range there is a problem that the adhesive strength with the underwater structure is weakened.

In addition, it is preferable to use titanium white of the curing composition in water in an amount of 5 to 15% by weight in the curing composition in water, and when it exceeds the above range, there is a problem in that cracking and aging occur and durability is weakened. There is a problem that the chemical resistance is reduced.

The present invention also provides a method for producing an underwater ceramic coating corrosion inhibitor, an underwater ceramic coating corrosion inhibitor and a method for preventing corrosion of an underwater structure using the tape impregnated therewith.

The present invention is to prepare an underwater ceramic coating composition by stirring (i) a polymer resin, a ceramic filler and a metal having a higher ionization degree than iron for 60 to 180 minutes to produce an underwater ceramic coating corrosion inhibitor, (Ii) stirring the acid anhydride, aliphatic polyamine, dicyandiamide, titanium white and the like at 20 to 50 ° C. for 5 to 90 minutes to prepare an underwater curing composition, and (iii) the ceramic coating composition and the underwater curing composition. 4.5: 1 to 11: 1 ratio is mixed and stirred for 3 to 30 minutes. Steps (iii) and (ii) proceed respectively, and the mixing ratio of step (iii) can be adjusted within the range according to the temperature and water temperature, and after completion of the mixing and stirring of step (iii), curing is performed. The pot life is about 60 to 120 minutes.

In another aspect, the present invention provides a method for preventing corrosion of an underwater structure coating the underwater ceramic coating corrosion inhibitor by any one of the method selected from the automatic airbrush, brush, roller and hera coating method, wherein the preferred coating film The thickness is 1-2 mm.

In another aspect, the present invention comprises the step of impregnating the water-based ceramic coating corrosion inhibitor to the (i) the tape, and (ii) 20 to 90% overlapping the coated tape to apply the underwater structure of the underwater structure comprising the It provides a corrosion prevention method, wherein the tape has a property of improving the toughness, strength, adhesion of the coating film and preventing cracking and dropping, and the material may be polyester, carbon fiber, or polyethylene, and preferably a tensile force. This strong polyester is used. In addition, depending on the degree of overlap of the tape can be coated with the desired thickness of the coating film, the thickness of the preferred coated coating film is 1.5 ~ 5 mm. If the coated tapes are laminated less than 20%, it is difficult to obtain a sufficient corrosion protection effect, and there is a high risk that the underwater structure will be exposed to water due to physical impacts, and if it is laminated more than 90%, the efficiency and cost of work will be a problem. There is. In addition, in the case of a cylindrical underwater structure, after the step (iii) and (ii) it may be optionally added to the step of packing with a PVC sheet or polyethylene sheet, in this case it can maximize the characteristics as a corrosion protection and reinforcement.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

EXAMPLES Preparation of Steel Pipe Piles Coated with Underwater Preservatives

The ceramic coating composition was prepared by stirring the composition at 80 ° C. at 450 rpm for 80 minutes by the composition of Table 1, and the cured underwater composition was also prepared by stirring at the stirring speed of 150 rpm at 40 ° C. for 60 minutes by the composition of Table 1. The ceramic coating composition and the water cured composition were mixed at a ratio of 8: 1, stirred at 80 rpm for 5 minutes, and uniformly mixed to prepare an underwater ceramic coating corrosion inhibitor, and the underwater ceramic coating agent prepared once was used within 90 minutes of preparation. . The underwater ceramic coating preservative was impregnated with a ceramic roller on both sides of a 20 cm wide polyester tape. A steel pipe pile coated with the ceramic coating agent in water was fixed by dipping a steel pipe pile having a thickness of 7 mm, a diameter of 355 mm, and a length of 10 m to 9 m in water in seawater to prepare a steel pipe pile coated with a ceramic coating corrosion inhibitor in water.

Component Ratios of Ceramic Coating Compositions and Aqueous Curing Compositions Material used Ratio (% by weight) Ceramic coating composition PVDF Resin 38 Alumina 13 Calcium carbonate 10 Magnesium silicate 7 Calcium silicate 5 zinc 24 Benton 2 Polyethylene glycol 0.7 Thymol 0.3 system 100 Underwater Curing Composition Methylnanik 40 Diethylenetriamine 30 Dicyandiamide 20 Titanium white 10 system 100

Comparative example

Steel pipe pile not coated with an underwater ceramic coating corrosion inhibitor of the above Example 1 was prepared as Comparative Example 1, and prepared in the same manner as in Example 1, the water-based ceramic coating corrosion inhibitor having a composition of Table 2 coated with a steel pipe pile as Comparative Example 2 It was.

Component Ratios of Ceramic Coating Compositions and Aqueous Curing Compositions Material used Ratio (% by weight) Ceramic coating composition Bisphenol A epoxy resin 43 burr 20 Alumina 20 Denatured urea solution 7 Basic chromate 4 Wax additive 2 Rutile Titanium Oxide 2 Polymethylalkylsiloxane One Dimethyl Polysiloxane 0.5 Polydimethylsiloxane Solution 0.5 system 100 Underwater Curing Composition Modified aliphatic amines 85 Tertiary amine 2 Denatured urea solution 13 system 100

Test Example 1: Adhesion Check Test

As a result of testing the adhesive strength after 6 hours of coating the corrosion inhibitor in seawater with the steel pipe pile of Examples and Comparative Examples 2, the corrosion inhibitor was adhered to the steel pipe pile in the case of Example, but in the case of Comparative Example 2, hardening does not occur in water. It could not be confirmed that it did not adhere.

Test Example 2: Salt Spray Test

In order to accelerate the corrosion resistance test of the steel pipe pile of Example 1, Comparative Examples 1 and 2, a saline spray test (Korean Industrial Standard KS D 9502) was carried out for 240 hours. In Examples 1 and 2, especially Comparative Example 1, it can be seen that the corrosion occurs badly.

Test Example 3: Preservation Test

The steel pipe piles of Examples and Comparative Examples 1 and 2 were preserved for 9 months to compare the appearance, the degree of attachment of fish and shellfish, and the corrosion resistance (ratio of corroded surface area) through the naked eye. Each item was evaluated by a 5 point grading method with 1 as the best and 5 as the worst. As a result of observing the overall appearance, the degree of adhesion of fish and shellfish, and corrosion resistance up to 9 months, it was found that the case of Example is much superior to Comparative Examples 1 and 2.

Results of appearance, adhesion of fish and shellfish, and corrosion resistance during the storage period 3 months 6 months 9 months Example Exterior One One One Attachment of fish and shellfish One One 2 Corrosion resistance One One One Comparative Example 1 Exterior 2 4 5 Attachment of fish and shellfish 3 5 5 Corrosion resistance 3 4 5 Comparative Example 2 Exterior 2 3 4 Attachment of fish and shellfish 2 3 5 Corrosion resistance 3 4 5

As described above, the present invention is a ceramic coating corrosion inhibitor which can be cured in water, including polymer resin, ceramic, metal having a higher ionization degree than iron, and sedimentation inhibitor, and has high bonding strength with steel structure (metal, concrete), and seawater. It is a low viscosity corrosion inhibitor that does not decompose in water such as rivers, and has excellent chemical resistance and anti-adhesion ability of aquatic organisms such as fish and shellfish. Underwater corrosion prevention method using tape impregnated with ceramic coating corrosion inhibitor prevents corrosion in water even for cylindrical piles, sheet (U) piles and H-shaped piles, as well as for complex shaped underwater structures consisting of polygons, irregularities and flanges The work can be easily performed and the durability is excellent for maintenance of underwater structure The cost can be reduced.

Claims (12)

Polyvinylidene fluoride resin 27.5 to 45 wt%; 27.5 to 45 wt% of ceramic filler having a particle size of 0.02 to 5 μm; And ceramic coating composition comprising 15 to 28% by weight of the metal having a greater ionization than iron (Fe) having a particle size of 0.1 to 10 ㎛, 25-50 wt% acid anhydride; Aliphatic polyamine 20 to 45 wt%; Dicyandiamide 20-28 wt%; And an underwater curing composition comprising 5-15 wt% of titanium white, A ceramic coating corrosion inhibitor for underwater corrosion prevention work comprising the ceramic coating composition and the cured composition in water in a weight ratio of 4.5: 1 to 11: 1. The ceramic coating corrosion inhibitor according to claim 1, wherein the ceramic coating composition contains 1.3 to 3.5% by weight of benton or polyolefin as a precipitation inhibitor. The ceramic coating corrosion inhibitor according to claim 1 or 2, wherein the ceramic coating composition contains 0.5 to 2% by weight of polyethylene glycol or glycerin fatty acid ester as a surfactant. The ceramic coating corrosion inhibitor according to claim 1, wherein the ceramic filler is used by mixing at least one of alumina, calcium carbonate, magnesium silicate and calcium silicate. The method of claim 4, wherein 9 to 19% by weight of alumina, 7 to 13% by weight of calcium carbonate, 4 to 11% by weight of magnesium silicate and 2 to 8% by weight of calcium silicate ceramics for corrosion prevention work Coating preservatives. delete delete delete (Iii) 27.5 to 45 weight percent of a polyvinylidene fluoride resin; 27.5 to 45 wt% of ceramic filler having a particle size of 0.02 to 5 μm; And preparing a ceramic coating composition by stirring 15 to 28 wt% of a metal having a higher ionization degree than iron (Fe) having a particle size of 0.1 to 10 μm at 60 to 90 ° C. for 60 to 180 minutes. (Ii) 25-50 wt% acid anhydride; Aliphatic polyamine 20 to 45 wt%; Dicyandiamide 20-28 wt%; And stirring 5-15 wt.% Titanium white at 20-50 [deg.] C. for 5-90 minutes to prepare a curable composition in water; (Iii) mixing the ceramic coating composition and the cured composition in water in a ratio of 4.5: 1 to 11: 1 to stir for 3 to 30 minutes, thereby preparing a ceramic coating corrosion inhibitor for underwater corrosion protection; And (Iii) a method of preventing corrosion of an underwater structure by coating the underwater structure in water with an automatic airbrush, brush, roller or hera coating method in water with the ceramic coating corrosion inhibitor. (Iii) 27.5 to 45 weight percent of a polyvinylidene fluoride resin; 27.5 to 45 wt% of ceramic filler having a particle size of 0.02 to 5 μm; And preparing a ceramic coating composition by stirring 15 to 28 wt% of a metal having a higher ionization degree than iron (Fe) having a particle size of 0.1 to 10 μm at 60 to 90 ° C. for 60 to 180 minutes. (Ii) 25-50 wt% acid anhydride; Aliphatic polyamine 20 to 45 wt%; Dicyandiamide 20-28 wt%; And stirring 5-15 wt.% Titanium white at 20-50 [deg.] C. for 5-90 minutes to prepare a curable composition in water; (Iii) mixing the ceramic coating composition and the cured composition in water in a ratio of 4.5: 1 to 11: 1 to stir for 3 to 30 minutes, thereby preparing a ceramic coating corrosion inhibitor for underwater corrosion protection; (Iii) impregnating and coating a tape with the ceramic coating preservative; And (Iii) laminating and applying the coated tape 20 to 90% overlapping the underwater structure in water, Corrosion prevention method of the underwater structure, characterized in that the thickness of the coated film is 1.5 ~ 5 mm. 11. The method of claim 10, wherein the material of the tape is any one selected from polyester, carbon fiber and polyethylene. 12. The method of claim 10 or 11, comprising wrapping the underwater structure with a PVC sheet or polyethylene sheet when the underwater structure is cylindrical.