JP2005002456A - Corrosion prevention structure of metallic structure, corrosion prevention method and corrosion-preventing body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the corrosion prevention structure of a metallic structure with which corrosion prevention stable over a long period of time can easily and securely be applied even to a metallic structure having complicated structure. <P>SOLUTION: In the corrosion prevention structure of the metallic structure, the surface of the metallic structure 2 to be subjected to corrosion prevention is provided with a liquid-permeable layer 3, further, the outside of the liquid-permeable layer 3 is provided with a corrosion prevention layer 4, wherein the corrosion prevention layer 4 consists of a composite containing: a galvanic-anodic metal with a potential lower than that of the metal composing the metallic structure 2 to be subjected to corrosion prevention; and an electrolyte forming material. The outside of the corrosion prevention layer 4 is preferably provided with a covering layer 6. The corrosion prevention structure is preferably provided with an electrically conductive material 5 arranged in such a manner that one end part thereof is joined to the metallic structure 2 to be subjected to corrosion prevention and the other end part reaches the corrosion prevention layer 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anticorrosion structure and an anticorrosion method for a metal structure in an atmospheric corrosive environment, in particular, an atmospheric metal structure that is repeatedly dried and wet by rainwater or the like, and an anticorrosive body used therefor.
[0002]
[Prior art and problems to be solved by the invention]
Corrosion countermeasures for metal structures in an atmospheric corrosive environment are performed by coating or coating with anticorrosion tapes. These anti-corrosion measures are not able to exert anti-corrosion performance unless sufficient removal of corrosion products, that is, rust, and because it is necessary to perform a defect-free coating operation even for a complex structure. It takes a lot of time and money. As a technique for solving such a problem, a technique described in Patent Document 1 below has been proposed, but a simpler and more effective anticorrosion means has been desired.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-348689
Accordingly, an object of the present invention is to provide an anticorrosion structure, an anticorrosion method, and an anticorrosive body for a metal structure that can easily and reliably prevent corrosion even with a metal structure having a complicated structure.
[0005]
[Means for Solving the Problems]
The present invention is an anticorrosion structure of a metal structure in which an anticorrosion layer is provided on the surface of an anticorrosive metal structure via a liquid-permeable layer or a moisture-permeable layer, and the galvanic anode layer is the anticorrosion layer The object is achieved by providing an anticorrosion structure for a metal structure made of a composite containing an anodic metal having a lower potential than the metal constituting the metal structure and an electrolyte forming material.
[0006]
Further, the present invention includes a composite containing a galvanic anodic metal having an electric potential lower than that of the metal constituting the corrosion-protected metal structure and an electrolyte-forming material in a liquid-permeable or moisture-permeable container, The object is achieved by providing a method for preventing corrosion of a metal structure in which the surface of the metal structure to be protected is covered with a housing material.
[0007]
In addition, the present invention provides a composite containing an galvanic anodic metal having a lower potential than the metal constituting the metal structure to be protected and an electrolyte forming material, and a liquid-permeable or moisture-permeable container containing the composite. The object is achieved by providing an anticorrosive body comprising a material.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings.
[0009]
FIG. 1 schematically shows one embodiment of a corrosion prevention structure (hereinafter also simply referred to as a corrosion prevention structure) of a metal structure of the present invention. In FIG. 1, the code | symbol 1 has shown the anticorrosion structure.
[0010]
In the anticorrosion structure 1 of the present embodiment, the anticorrosion layer 4 is provided on the surface of the metal structure 2 to be protected via the liquid-permeable layer 3. The anticorrosion structure 1 of the present embodiment has one end joined to the anticorrosive metal structure 2 and a conductive material 5 that electrically connects the anticorrosive metal structure 2 and the anticorrosion layer 4. A coating layer 6 is further provided outside the anticorrosion layer 4. In the anticorrosion structure 1, the liquid permeable layer 3 and the buffer layer 7 are provided between the anticorrosion layer 4 and the coating layer 6.
[0011]
The liquid permeable layer 3 is not particularly limited as long as it has liquid permeability and, as will be described later, can exhibit an anticorrosion effect when it is eluted into the liquid that has passed through the galvanic anode metal. In view of excellent flexibility, stretchability, durability, handleability and the like, it is preferable to use a nonwoven fabric, a woven fabric or a porous film. Although there is no restriction | limiting in particular in the material of the fiber of these nonwoven fabrics and woven fabrics, The fiber which has a hydrophilic group is preferable and fibers, such as nylon fiber and an acrylic fiber, are mentioned, for example. The porous film is preferably a polymer film having a large number of pores having a pore diameter of 0.4 μm or more. Examples of the material for the porous film include polyethylene and polypropylene.
[0012]
The thickness of the liquid permeable layer 3 is preferably 0.02 to 5 mm. When the liquid-permeable layer 3 is composed of the nonwoven fabric or the woven fabric, a thickness of 1 to 5 mm is preferable. Moreover, when the liquid-permeable layer 3 is comprised with the said porous film, thickness is 0.02-0.25 mm. These thicknesses are set according to durability, handleability, and the like. The liquid-permeable layer 3 can be fixed to the surface of the corrosion-protected metal structure 2 by a method such as adhesion within a range that does not affect the effects of the present invention.
[0013]
The anticorrosion layer 4 is made of a composite containing an galvanic anodic metal having a lower potential than the metal constituting the anticorrosive metal structure 2 and an electrolyte forming material.
[0014]
The galvanic anodic metal is appropriately selected according to the metal constituting the corrosion-protected metal structure 2. When the corrosion-protected metal structure 2 is a steel structure, one made of zinc, aluminum, magnesium, or an alloy thereof is preferable. Examples of the zinc alloy include Zn / 0.2 to 0.7 mass% Al / 0.03 to 0.14 mass% Cd series. Examples of the aluminum alloy include Al / 1 to 10 mass% Zn / 0.1 to 6 mass% Mg / 0.01 to 0.04 mass% In / 0.5 to 1 mass% Si. Examples of the magnesium alloy include alloys described in JIS H6125.
[0015]
The galvanic anodic metal is not particularly limited as long as it can be uniformly combined with an electrolyte forming material to be described later, but it is ribbon-like, sheet-like, fibrous, granular, linear, wire mesh, etc. Is preferable. Further, the size is not particularly limited as long as it can be uniformly combined, but the following sizes are used in consideration of handling property, cost, and the like. In the case of a ribbon, a width of 1 to 20 mm, a length of 100 to 1000 mm, and a thickness of 0.1 to 1 mm are preferable. In the case of a sheet, a thickness of 1 to 2 mm is preferable. In the case of powder, the average particle size is preferably 1 mm or less, and particularly preferably contains 80 to 50% by mass of 70 to 150 μm particles. In the case of a linear shape, a wire diameter of 1 to 2 mm is preferable. In the case of a wire mesh, a wire diameter of 1 to 2 mm and a pitch width of 10 to 30 mm are preferable.
[0016]
The electrolyte-forming material can sufficiently hold the liquid that has permeated the liquid-permeable layer 3 (including the condensed vapor of the liquid), and when the galvanic anode metal is eluted in the held liquid, There is no particular limitation as long as the electrolyte-forming material can function as an electrolyte so that the anticorrosion effect is exhibited. The electrolyte-forming material is preferably a water-absorbing polymer in consideration of water absorption performance, swelling characteristics, handleability, cost, and the like. Examples of the water-absorbing polymer include polyacrylate, saponified vinyl acetate / acrylic acid ester copolymer, polyvinyl acetate / maleic anhydride reaction product, cross-linked isobutylene / maleic acid copolymer, polyethylene oxide, starch / Acrylic acid graft polymer, polyvinyl alcohol type, poly N-vinylacetamide type and the like can be mentioned.
[0017]
The form of the electrolyte forming material is not particularly limited as long as it can be uniformly combined with the galvanic anodic metal, but a form such as powder, fiber, and sheet is preferable. Since widely available general-purpose products can be used, the size is not particularly limited. In the case of a granular form, those of 0.8 to 2.8 mm are particularly preferable.
[0018]
The mixing ratio of the galvanic anodic metal and the electrolyte forming material is 10 to 50%, particularly 20 to 40%, in volume ratio of the galvanic anodic metal to the total volume of the galvanic anode metal and the electrolyte forming material. Is preferred. The blending amounts of the galvanic anodic metal and the electrolyte forming material are set according to the anticorrosion period, the material used, the handleability thereof, and the like.
[0019]
In addition to the galvanic anodic metal and the electrolyte-forming material, additives such as water-absorbing paper, pulp fiber, and glass fiber can be added to the composite at an appropriate ratio.
[0020]
The thickness of the anticorrosion layer 4 is set according to the anticorrosion period or workability, but is preferably 1 to 5 mm.
[0021]
The conductive material 5 secures electrical conduction between the corrosion-protected metal structure 2 and the anticorrosion layer 4 and further enhances the electrocorrosion effect, so that the other end reaches the anticorrosion layer 4. It is arranged. Although there is no restriction | limiting in particular in the form of the electrically conductive material 5, In this embodiment, the electrically conductive material 5 is comprised with the pin. In the case of the pin, the conductive material 5 is one having a protrusion length from the surface of the metal structure 2 to be protected of 1 to 5 mm and a thickness (φ) of 2 to 5 mm in consideration of workability or cost. preferable. Further, when the conductive material 5 is the pin, it is preferable to join the surface of the metal structure 2 to be protected at a rate of 2 / m ² or more in order to achieve the above-described anticorrosion effect. The method for joining the conductive material 5 to the surface of the corrosion-protected metal structure 2 is not particularly limited as long as the above-described conduction is ensured. The joining method is preferably a welding method such as arc welding. Examples of the material of the conductive material 5 include steel, brass, and stainless steel.
[0022]
The coating layer (protective layer) 6 protects the anticorrosion layer 4. The coating layer 6 is the same as the conventional one. Examples of the material of the coating layer 6 include FRP (fiber reinforced plastic) using polyester resin, epoxy resin, polypropylene resin, vinyl chloride resin, and high strength polyethylene as plastic, and seawater-resistant stainless steel as metal. And titanium.
[0023]
The buffer layer 7 enhances the sealing property between the anticorrosion layer 4 and the protective layer 6. The buffer layer 7 is the same as the conventional one. Examples of the material of the buffer layer 7 include foamed materials such as foamed polyethylene, foamed polyurethane, and foamed styrene.
[0024]
In the anticorrosion structure 1 of the present embodiment, when moisture or rainwater in the atmosphere penetrates into the surface of the metal structure 2 to be protected, the water or water vapor passes through the liquid-permeable layer 3 and enters the anticorrosion layer 4. The electrolyte is formed by being absorbed and held by the electrolyte forming material. Then, a circuit is formed between the electrolyte and the galvanic anodic metal and the corrosion-protected metal structure 2 through the liquid-permeable layer 3 or through the conductive material 5, thereby exhibiting an anti-corrosion action. . Thereby, the surface of the to-be-corroded metal structure 2 is corroded.
[0025]
The said anticorrosion structure 1 can be provided by embodiment of the anticorrosion body of this invention mentioned later or the anticorrosion method of this invention, for example.
[0026]
Next, the anticorrosive body of this invention is demonstrated based on the preferable embodiment. In addition, in the following description, the description is abbreviate | omitted about the part which is common in the anticorrosion structure 1 of the said embodiment. Therefore, the description in the anticorrosion structure 1 of the above embodiment is appropriately applied to portions that are not particularly described.
[0027]
FIG. 2 shows an embodiment in which the anticorrosive body of the present invention is applied to an anticorrosive body that protects the pedestal portion of a steel pier. Reference numeral 10 denotes an anticorrosive body.
[0028]
As shown in FIG. 2, the anticorrosion body 10 includes a composite 40 containing an anodic metal having a potential lower than that of the metal constituting the metal structure to be protected and an electrolyte forming material, and a transparent material containing the composite 40. And a liquid or moisture-permeable container 30. Further, the anticorrosive body 10 includes a covering material 60 that covers the outside of the housing material 30.
[0029]
The container 30 has liquid permeability or moisture permeability and is not particularly limited in its form as long as it can accommodate the composite 40. However, in consideration of workability and the like, preventing the composite from falling off. A bag or a needle punched around the bag is preferable. The container 30 is formed of the same nonwoven fabric, woven fabric, or porous film as the liquid-permeable layer 3. The container 30 is preferably sealed around the composite 40 so that the composite 40 does not leak out.
[0030]
For the composite 40, the composite in the anticorrosion layer 4 is used.
[0031]
The covering material 60 constitutes the covering layer 6 and adheres the containing material 30 to the surface of the pedestal that is the metal structure to be protected with a predetermined strength. In this embodiment, the cross section is semicircular and has a flange portion 61 at the edge. The flange portion 61 is provided with a fixing bolt hole 62. The form of the covering material 60 is set according to the form of the anticorrosion object, the anticorrosion site, and the like. The covering material 60 is made of the same material as the covering layer 6.
[0032]
The containing material 30 is preferably fixed inside the covering material 60. Although there is no restriction | limiting in particular in the fixing method to the coating | covering material 60 of the accommodating material 30, The well-known fixing method using adhesion | attachment means, such as an adhesive agent, and a fixing jig is employable. Also, known fixing means such as an engaging portion can be provided on either or both of the accommodating material 30 and the covering material 60.
[0033]
Although the accommodating material 30 can be directly fixed to the covering material 60, as in the present embodiment, a cushioning material 70 is interposed between them so that the covering material 60 can adhere to the pedestal of the accommodating material 30. It is preferable to increase. The buffer material 70 is made of the same material as the buffer layer 7.
[0034]
Although there is no restriction | limiting in particular in the fixing method to the accommodating material 30 and the coating | covering material 60 of the buffer material 70, The well-known fixing method using adhesive means, such as an adhesive agent, and a fixing jig is employable. In addition, any or all of the buffer material 70, the storage material 30 and the covering material 60 may be provided with known fixing means such as an engaging portion.
[0035]
Next, the corrosion prevention method for a metal structure according to the present invention will be described with reference to FIG. 3 as a preferred embodiment based on an embodiment applied to corrosion prevention of a pier column portion of a bridge pier using the corrosion prevention body 10. To do. In FIG. 3, the code | symbol 100 has shown the pier. In addition, in the following description, the description is abbreviate | omitted about the part which is common in the anticorrosion structure 1 of the said embodiment. Therefore, the description in the anticorrosion structure 1 of the above embodiment is appropriately applied to portions that are not particularly described.
[0036]
First, a base material adjustment is performed for a metal structure to be protected, which is an object of corrosion protection, that is, a pedestal portion (a range of corrosion protection) of the bridge pier 100. It is preferable that this base material adjustment is conventionally performed by a base material adjusting method for corrosion protection of steel, for example, ISO-St2 (Kellen by hand tool).
[0037]
Next, the pins 50 serving as the conductive material 5 are joined to the surface of the pedestal portion at a predetermined ratio. The joining method is as described above.
[0038]
Next, the said anticorrosion body 10 is attached so that a pedestal part may be coat | covered. At the time of attachment, the pin 50 is attached so as to penetrate the housing material 30 and the tip thereof reaches the composite. In addition, in the range which does not affect the effect of this invention, the accommodating material 30 can also be adhere | attached on the surface of a pedestal part with an adhesive agent etc.
[0039]
Next, the flange portions 61 are brought into contact with each other, and the bolt 63 is passed through the bolt hole 62 and tightened with a desired strength to complete the corrosion prevention.
[0040]
As described above, according to the anticorrosive body 10 of the present embodiment and the anticorrosion method using the anticorrosive body 10, the anticorrosion of the pedestal portion of the pier 100 can be performed easily and reliably for a long period of time.
[0041]
FIG. 4 shows an embodiment in which the present invention is applied to corrosion prevention of the corner end portion of the overhanging portion of the pier. In the case of this embodiment, a notch portion 64 for the stat bolt is provided in the covering material 60 of the anticorrosive body 10 ′, and a stat bolt 65 is welded to the overhanging portion of the pier 100, and the stat bolt is attached to the notch portion 64. The bolt 65 is inserted and the nut 66 is tightened and attached to the stat bolt 65. Thereby, corrosion prevention of the corner edge part of the overhang | projection part of a bridge pier can be performed simply and reliably for a long term stably.
[0042]
The present invention can also be applied to anticorrosion of the support portion of the bridge girder. In this case, a strip-shaped anticorrosive body 10 ′ prepared in advance as shown in FIG. 5A can be used. This anticorrosive body 10 'includes a zinc-based metal net formed into a tubular shape in a container 30 made of a nonwoven fabric as the liquid-permeable layer 3, and a galvanic anode metal in which ribbon-like zinc is accommodated in the metal mesh And a composite 40 as the anticorrosion layer 4 made of a water-absorbing polymer as an electrolyte forming material. In the anticorrosion structure shown in FIG. 5 (b), the anticorrosive body 10 'is disposed around the support part 101 of the bridge girder to which the pin (conductive material) 5 is welded so as not to interfere with the function of the support part. A pin 5 is wound around and a resin frame material (covering material) 60 is fixed to an abutment (or pier) 102 as a covering layer 6 around the pin 5. In this way, the anticorrosive body 10 'of the present embodiment forms the anticorrosion structure of the support portion 101 in this way, and thus can easily and reliably prevent corrosion of the support portion for a long period of time.
[0043]
The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention.
[0044]
In the present invention, it is preferable to join the conducting material 5 to the surface of the corrosion-protected metal structure 2 as in the above embodiment, but when sufficient conduction can be secured by the liquid-permeable layer or the moisture-permeable layer, The conductive material can be omitted.
[0045]
In the present invention, it is preferable that the liquid-permeable layer 3 is provided between the metal structure to be protected 2 and the anti-corrosion layer 4 as in the above-described embodiment. A moisture permeable layer may be provided instead of the permeable layer.
[0046]
Moreover, although the anticorrosion method of this invention attaches the anticorrosion body 10 manufactured previously to the anticorrosion object part of a to-be-protected metal structure on-site like the said embodiment, the said anticorrosion body is manufactured on the spot. And anticorrosion can be performed.
[0047]
The anticorrosion structure of the present invention is preferably provided as in the above-described embodiment. For example, when the anticorrosion target portion is flat, the nonwoven fabric or the like is laid on the target portion, and the liquid-permeable layer 3 is provided. After providing, the said composite is spread | dispersed on this liquid-permeable layer 3, the said anti-corrosion layer 4 is provided, and this anti-corrosion layer 4 is coat | covered with the coating layer 6 through the said buffer layer 7, and is provided. it can.
[0048]
As long as the metal structure to which the present invention is applied is a metal structure in an atmospheric environment, the scope of application is not limited. In addition to steel piers, steel bridges and structures of various plant facilities are listed.
[0049]
【The invention's effect】
According to the present invention, even a metal structure having a complicated structure can be subjected to corrosion prevention simply and reliably and stably.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part schematically showing an embodiment of a corrosion prevention structure for a metal structure of the present invention.
FIG. 2 is a view schematically showing an embodiment of the anticorrosive body of the present invention, wherein (a) is a cross-sectional view (a cross-sectional view taken along line AA in (b)), and (b) is a front view.
FIG. 3 is a diagram schematically showing a corrosion prevention procedure according to an embodiment of the corrosion prevention method for a metal structure of the present invention, (a) is a diagram showing a state before corrosion prevention, and (b) is a conductive material (pin). (C) is a figure which shows the state which attached the anticorrosion body.
FIG. 4 is a partial cross-sectional view schematically showing an anticorrosion structure using another embodiment of the anticorrosive body of the present invention.
5A and 5B are diagrams schematically showing another embodiment of the anticorrosive body of the present invention and an anticorrosion structure using the same, wherein FIG. 5A is a cross-sectional view of the anticorrosive body, and FIG. 5B is a partial cross-sectional view of the anticorrosive structure. It is.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Corrosion prevention structure of metal structure 2 Corrosion prevention metal structure 3 Liquid permeable layer or moisture permeable layer 4 Corrosion prevention layer 5 Conductive material 6 Covering layer 7 Buffer layer 10 Corrosion prevention body 30 Housing material 40 Composite 60 Covering material 70 Buffer material

Claims (10)

An anticorrosion structure of a metal structure in which an anticorrosion layer is provided on the surface of the protected metal structure via a liquid-permeable layer or a moisture-permeable layer,
An anticorrosion structure for a metal structure, wherein the anticorrosion layer is composed of a composite containing an galvanic anodic metal having a lower potential than the metal constituting the anticorrosive metal structure and an electrolyte forming material. The anticorrosion structure for a metal structure according to claim 1, wherein a coating layer is further provided outside the anticorrosion layer. 3. The corrosion prevention structure for a metal structure according to claim 1, wherein a part of the corrosion prevention metal structure is bonded to the corrosion protection metal structure, and a conductive material for conducting the corrosion protection metal structure and the corrosion protection layer is disposed. The said liquid-permeable layer or the said moisture-permeable layer consists of a nonwoven fabric, a woven fabric, or a porous film, The anticorrosion structure of the metal structure in any one of Claims 1-3. The anticorrosion structure for a metal structure according to any one of claims 1 to 4, wherein the electrolyte forming material comprises a water-absorbing polymer. The composite containing the galvanic anodic metal having a lower potential than the metal constituting the metal structure to be protected and the electrolyte forming material is stored in a liquid-permeable or moisture-permeable storage material, and then the corrosion-protected material is stored in the storage material. A method for preventing corrosion of a metal structure that covers the surface of the metal structure. The method for preventing corrosion of a metal structure according to claim 6, wherein the outside of the housing is further covered with a covering material. A composite comprising a galvanic anodic metal having a lower potential than the metal constituting the corrosion-protected metal structure and an electrolyte forming material; and a liquid-permeable or moisture-permeable containing material containing the composite. Anticorrosive body. The anticorrosive body according to claim 8, wherein the containing material is a bag formed of a nonwoven fabric, a woven fabric, or a porous film. The anticorrosive body of Claim 8 or 9 provided with the coating | covering material which coat | covers the outer side of the said accommodating material.

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