阅读说明：本技术 一种大气环境下对金属利用涂层和外加电流阴极联合保护技术 (Combined protection technology for metal by utilizing coating and impressed current cathode in atmospheric environment ) 是由 邓培昌 胡杰珍 王贵 刘文娟 黄欢 于 2021-01-12 设计创作，主要内容包括：本发明公开了一种大气环境下对金属利用涂层和外加电流阴极联合保护技术,在所述金属表面依次涂敷有底漆层,导电涂层和面漆层；所述金属和导电涂层通过导线连接直流电源；其中,所述金属与直流电源负极连接,所述导电涂层与直流电源的正极连接。通过给金属与导电涂层之间施加一定的电源,当涂层出现微裂纹时,金属表面的薄液膜沿着裂纹渗入充当电解质溶液,实现了外加电流阴极保护技术。本发明实现对金属的外加电流阴极保护,同时提高了涂层的利用率和金属的使用期限。利用本涂层和外加电流阴极保护技术对金属进行联合保护,可使得金属基体不被腐蚀,以及延长涂层材料的使用寿命。(The invention discloses a combined protection technology for metal by utilizing a coating and an impressed current cathode in an atmospheric environment, wherein a primer layer, a conductive coating and a finish paint layer are sequentially coated on the surface of the metal; the metal and the conductive coating are connected with a direct current power supply through a lead; the metal is connected with the negative electrode of the direct current power supply, and the conductive coating is connected with the positive electrode of the direct current power supply. By applying a certain power supply between the metal and the conductive coating, when the coating has microcracks, a thin liquid film on the surface of the metal permeates into the conductive coating along the cracks to serve as an electrolyte solution, so that the impressed current cathodic protection technology is realized. The invention realizes impressed current cathodic protection of metal, and simultaneously improves the utilization rate of the coating and the service life of the metal. The combined protection of metal by using the coating and impressed current cathodic protection technology can prevent the metal matrix from being corroded and prolong the service life of the coating material.)

1. A combined protection technology for metal by utilizing a coating and an impressed current cathode in atmospheric environment is characterized in that: sequentially coating a primer layer, a conductive coating and a finish paint layer on the metal surface; the metal and the conductive coating are connected with a direct current power supply through a lead; the metal is connected with the negative electrode of the direct current power supply, and the conductive coating is connected with the positive electrode of the direct current power supply.

2. The joint protection technique of claim 1, wherein: the conductive material of the conductive coating is graphene, nickel powder, zinc powder, carbon fiber, carbon nano tube or polyaniline modified glass flake; the film forming material of the conductive coating is epoxy resin, acrylic resin or fluorocarbon resin.

3. The joint protection technique of claim 2, wherein: the conductive coating is a mixture of the graphene and epoxy resin; wherein the weight percentage of the graphene is 45-60%, and the rest is epoxy resin.

4. The joint protection technique of claim 2, wherein: the conductive coating is a mixture of the nickel powder and acrylic resin; wherein the weight ratio of the nickel powder is 35-42 parts, and the weight ratio of the acrylic resin is 30-45 parts.

5. The joint protection technique of claim 2, wherein: the conductive coating is a mixture of the carbon nano tube, fluorocarbon resin and a curing agent; wherein the weight percentage of the carbon nano tube is 1.0-3.5 percent, and the rest is fluorocarbon resin and curing agent.

6. The joint protection technique of claim 2, wherein: the conductive coating is a mixture of the polyaniline modified glass flakes and epoxy resin; wherein the polyaniline modified glass flake accounts for 10-25 parts by weight, and the epoxy resin accounts for 20-60 parts by weight.

7. The joint protection technique according to any one of claims 1 to 6, wherein: the finish paint is polyurethane or fluorocarbon paint, and the primer is sprayed epoxy primer.

Technical Field

The invention relates to the technical field of metal corrosion protection in atmospheric environment, in particular to a combined protection technology for metal by adopting a coating and an impressed current cathode in atmospheric environment.

Background

In recent years, China has rapidly developed ocean economy, and a large amount of maritime work equipment such as offshore oil platforms, harbor wharfs, sea-crossing bridges, offshore wind power and the like are developed. Most of the maritime work equipment is exposed to the atmosphere, so that the maritime work equipment is seriously corroded, the normal development of the maritime economy is seriously influenced, and huge economic losses are caused. Therefore, the corrosion rule and mechanism of the metal material in the atmospheric environment are systematically researched, scientific basis can be provided for material selection, design and corrosion standard establishment of marine engineering equipment, and the method has very important significance for the rapid development of marine economic health.

At present, the metal corrosion protection technology comprises two corrosion protection technologies, namely coating protection and impressed current cathodic protection. For the protection of metal components in atmospheric environment, coating technology is generally adopted at home and abroad, and for soil and conductive solution, impressed current cathodic protection technology is adopted. However, in the atmospheric environment, for metal devices or components directly exposed to the gas phase environment, the impressed current cathodic protection cannot be realized due to the lack of continuous conductive media.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a combined technology for coating and impressed cathodic current protection of metal in an atmospheric environment.

In order to achieve the purpose, the invention adopts the technical scheme that:

a joint protection technology for metal in an atmospheric environment by utilizing a coating and an impressed current cathode sequentially coats a primer layer, a conductive coating and a finish paint layer on the surface of the metal; the metal and the conductive coating are connected with a direct current power supply through a lead; the metal is connected with the negative electrode of the direct current power supply, and the conductive coating is connected with the positive electrode of the direct current power supply. By applying a certain power supply between the metal and the conductive coating, when the coating has microcracks, a thin liquid film on the surface of the metal permeates into the conductive coating along the cracks to serve as an electrolyte solution, so that the impressed current cathodic protection technology is realized. When the corrosion penetrates into the conductive coating, electrons are gathered to the cathode through the electrolyte solution, and the metal is protected, so that the impressed current cathodic protection is realized.

Further, the conductive material of the conductive coating is graphene, nickel powder, zinc powder, carbon fiber, carbon nano tube or polyaniline modified glass flake; the film forming material of the conductive coating is epoxy resin, acrylic resin or fluorocarbon resin. The film-forming material is generally dissolved by a solvent, and the film-forming material is obtained after the solvent is volatilized after coating. Solvents commonly used are, for example, acetone, propionic acid, toluene, xylene, dimethylformamide, acrylic acid.

Further, the conductive coating is a mixture of the graphene and epoxy resin; wherein the weight percentage of the graphene is 45-60%, and the rest is epoxy resin.

Further, the conductive coating is a mixture of the nickel powder and acrylic resin; wherein the weight ratio of the nickel powder is 35-42 parts, and the weight ratio of the acrylic resin is 30-45 parts.

Further, the conductive coating is a mixture of the carbon nano tube, fluorocarbon resin and a curing agent; wherein the weight percentage of the carbon nano tube is 1.0-3.5 percent, and the rest is fluorocarbon resin and curing agent.

Further, the conductive coating is a mixture of the polyaniline-modified glass flakes and epoxy resin; wherein the polyaniline modified glass flake accounts for 10-25 parts by weight, and the epoxy resin accounts for 20-60 parts by weight.

Further, the finish paint is polyurethane or fluorocarbon paint, and the primer is sprayed epoxy primer.

The invention has the beneficial effects that: the impressed current cathodic protection is carried out in the atmospheric environment, voltage is applied between the conductive coating and the metal, and a thin liquid film on the surface of the metal permeates through microcracks to serve as an electrolyte solution, so that the impressed current cathodic protection of the metal is realized, and the utilization rate of the coating and the service life of the metal are improved. The combined protection of metal by using the coating and impressed current cathodic protection technology can prevent the metal matrix from being corroded and prolong the service life of the coating material.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a schematic illustration of metal surface scoring according to an embodiment of the present invention;

number designation in the figures: 1-metal, 2-primer layer, 3-conductive coating, 4-finish layer and 5-scribing line.

The drawings are for illustrative purposes only and are not to be construed as limiting the patent; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present patent.

Detailed Description

The present invention will be further described in detail with reference to the following examples, which are a combined protection technique for metal by using a coating and an impressed current cathode in an atmospheric environment, wherein the relative humidity of a marine atmospheric environment is 95%, as shown in fig. 1, a metal 1 in the drawing is a carbon steel metal sample, and both sides of the metal 1 are sprayed with a layer of epoxy primer to form a primer layer 2, and the thickness of the primer layer is about 0.1 mm; the conductive coating 3 is prepared by dissolving epoxy resin and graphene in acetone in a ratio of 1:1, and after the conductive coating 3 is air-dried, polyurethane is sprayed to form a finish paint layer 4. Wherein before the conductive coating 3 is dried, the conductive wire is fixed on the surface by utilizing the inherent viscosity of the paint and connected with the positive electrode of the direct current power supply, one conductive wire is welded on the surface of the metal 1 and connected with the negative electrode, and certain voltage is applied to the two conductive wires. If the microcrack appearing on the surface of the metal 1 extends to the conductive coating 3, the thin liquid film on the surface layer of the metal 1 permeates along the microcrack to form a closed loop with the power supply and the metal 1, so that the impressed current cathodic protection of the metal in the atmospheric environment is realized. Five identical samples were prepared for the experiment and the same scoring was performed on the surface of the sample to break the coating. As shown in fig. 2; the sample a is not applied with voltage, the samples b, c, d and e are respectively applied with voltage of 0.3V, 0.6V,0.9V and 1.2V between the conductive coating 3 and the metal, and the surface appearance change of the carbon steel sample is observed after 20 days, so that the following observation results are obtained:

test sample	Applying a voltage	Results of the experiment after 20 days
			a	Is free of	The scratch part has been seriously corroded, and the generated corrosion products overflow the crack
b	0.3V	The more serious corrosion occurs at the scratch
			c	0.6V	No corrosion products were found in the crevices at the scratches
d	0.9V	No corrosion products were found in the crevices at the scratches
			e	1.2V	The corrosion products were found at the scratch, but to a lesser extent than the a sample

The experiment strongly proves the outstanding antirust effect of the technology, and the optimal effect can be achieved by reasonably selecting the voltage.

FIG. 1 is intended as an illustration only, and not as a limitation on the present patent; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present patent.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Variations or modifications in other variations may occur to those skilled in the art upon reading the foregoing description. For example, the conductive coating may be carbon fiber or the like, and need not be exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.