Conductive coating resistant to soil microbial corrosion and its preparation method and application

Abstract

The application provides an electrically conductive coating resistant to soil microbial corrosion and a preparation method and application thereof, and the electrically conductive coating comprises polyaniline-coated nano metal oxide, graphite, fluorocarbon resin, a curing agent and a solvent in specific proportions; by adding the polyaniline-coated nano metal oxide and the graphite, the electrically conductive coating has excellent broad-spectrum soil microbial corrosion resistance and electric conductivity, can be coated on the surface of grounding material, can effectively prevent the grounding material from being corroded by microorganisms, and can further improve the corrosion resistance and grounding current dispersion of the grounding material, so as to maximize the durability of the grounding material; meanwhile, the electrically conductive coating also has the advantages of high adhesion to a base material, wide application range, low cost, simple construction and environmental friendliness.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a conductive coating resistant to soil microbial corrosion, its preparation method, and its application. Background Technology

[0002] Grounding devices are an indispensable and crucial component of power systems. Soil corrosion of grounding materials not only reduces their service life but also increases the grounding resistance of the grounding grid, reducing the current dissipation capacity of the grounding electrode. Microbial corrosion (MIC) is a significant type of soil corrosion, accounting for approximately 20% of total losses. Studies have shown that more than half of underground structures in contact with soil, such as oil and gas pipelines, cables, electronic equipment, and foundations, are caused or involve microorganisms. Particularly in southern regions with suitable underground environmental temperatures, underground grounding grids are prone to microbial corrosion. Microorganisms in the soil, such as sulfate-reducing bacteria (SRB), iron bacteria (IB), iron-oxidizing bacteria (IOB), and sulfur-oxidizing bacteria (SOB), can directly or indirectly accelerate the material corrosion process through their life activities. For example, SRB significantly accelerates the corrosion of bare steel, with an average corrosion rate reaching 0.68 mm / a.

[0003] Currently, the mechanisms of microbial corrosion are mainly classified into two categories: First, aerobic bacteria produce inorganic acids during metabolism, creating a harsh corrosive environment on the material surface, thus exacerbating the corrosion of metallic materials. Second, common acid-producing bacteria, such as Clostridium acetic acid, metabolize to produce acetic acid, while sulfur-oxidizing bacteria utilize elemental sulfur, thiosulfates, and sulfites in the oxidizing environment to produce sulfuric acid, lowering the pH of the surrounding environment. Third, iron-oxidizing bacteria can accelerate the electrochemical processes of metals, causing Fe... 2+ Oxidized to Fe 3+ This leads to the formation of oxide precipitates, thereby accelerating the anodic process of metal corrosion. Anaerobic bacteria, especially SRB, are the most destructive soil microorganisms, corroding materials such as carbon steel, stainless steel, copper and its alloys, and aluminum and its alloys. The hydrogenases in SRB cells can utilize hydrogen on the metal surface to convert SO42- into SO42-. 2- The FeS film is reduced to H2S, thus acting as a cathodic depolarizer during corrosion and accelerating the process. In addition, the reaction products rapidly deposit on the metal surface, forming a loose, porous, and easily detachable FeS film. FeS becomes the cathode of the corrosion cell, forming a corrosion cell with the iron anode. Simultaneously, the cathodic depolarization hydrogen evolution reaction can also occur on the FeS surface, leading to corrosion.

[0004] The main methods for controlling microbial corrosion include (1) physical methods: using magnetic fields, ultrasonic treatment, ultraviolet irradiation, etc.; (2) biological methods: using the competition, antagonism and symbiotic relationship between microorganisms to inhibit the reproduction of corrosive bacteria; (3) cathodic protection; (4) chemical methods: adding bactericides and using corrosion-resistant coatings to change the surface properties of metals. Although there is a lot of research on the prevention and control of microbial corrosion in oilfield pipelines, there are few reports on grounding materials. For the protection of grounding materials against microbial corrosion, physical methods are not suitable for deep soil environments; biological methods can only be used in the living environment of certain specific bacteria, which is very limited; cathodic protection has no obvious inhibitory effect on microbial corrosion; the addition of bactericides will cause secondary pollution to the environment due to their own toxicity, and long-term and large-scale use will easily cause microorganisms to develop drug resistance, which will reduce the effectiveness of bactericides. At the same time, since most grounding materials do not have the function of resisting soil microbial corrosion, bactericides are often used in practice to inhibit the corrosion of materials by soil bacteria.

[0005] Therefore, to address the aforementioned technological gaps, there is an urgent need to develop a conductive coating that possesses excellent broad-spectrum resistance to soil microbial corrosion, as well as good electrical conductivity and environmental friendliness. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a conductive coating resistant to soil microbial corrosion, its preparation method, and its application. The conductive coating not only has excellent broad-spectrum anti-soil microbial corrosion function, but also possesses good conductivity, environmental friendliness, and excellent substrate adhesion. When applied to the surface of grounding materials, it can effectively prevent grounding materials from being corroded by microorganisms, thereby maximizing the service life of grounding materials.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a conductive coating resistant to soil microbial corrosion, wherein the conductive coating comprises the following components in parts by weight:

[0009]

[0010] The inventors of this invention have discovered that nano-Cu₂O and other metal oxides can enter sulfate-reducing bacteria (SRB) cells, disrupting enzyme proteins within the SRB cells, leading to SRB cell inactivation or even death, ultimately slowing down metal corrosion and achieving a protective effect. The proven antibacterial mechanism is mainly due to Cu… + and Cu 2+Redox reactions caused by electron transfer between microorganisms can produce highly oxidizing reactive oxygen species (ROS), such as ·OH. ROS interact with cell membranes to induce membrane permeability, lipid peroxidation, protein denaturation and inhibition of assembly and activity, and genetic material denaturation, thus promoting or causing bacterial death. However, nanoscale metal oxides are prone to aggregation and oxidation when used alone, which seriously affects their antibacterial and antiseptic properties.

[0011] Based on the above, the conductive coating provided by this invention, by selectively adding polyaniline-coated nano-metal oxides, effectively overcomes the problems of agglomeration and oxidation that easily occur when nano-sized metal oxides are used alone, improving the compatibility and interaction between the metal oxides and the fluorocarbon resin matrix. Furthermore, utilizing the large π-delocalized structure of polyaniline coated on the surface of the metal oxide, the average time for charge carriers to diffuse from the interior to the surface of the metal oxide is greatly shortened, reducing the probability of charge carrier recombination within the grains. This results in an increase in the number of charge carriers diffused to the surface, thereby generating a sufficient number of free radicals and enhancing the antibacterial ability of the metal oxide. In addition, since the polyaniline-coated nano-metal oxides also possess a certain degree of conductivity, they can further form a complete conductive network with the graphite in the conductive coating, further improving the conductivity and antimicrobial corrosion performance of the conductive coating.

[0012] In summary, the conductive coating provided by this invention, through the coordinated use of polyaniline-coated nano-metal oxides and graphite, not only possesses excellent broad-spectrum resistance to soil microbial corrosion but also exhibits good conductivity and environmental friendliness. As an anti-corrosion coating for grounding materials, it prevents microbial biofilms from adhering to the surface of the grounding material, isolates metabolic products from direct contact with the metal grounding material, and inhibits microbial growth, thereby effectively preventing the grounding material from being corroded by microorganisms. This improves the corrosion resistance and grounding current dissipation of the grounding material, maximizing its durability. Furthermore, the conductive coating also boasts advantages such as high adhesion to the substrate, wide applicability, low cost, simple construction, and environmental friendliness.

[0013] In this invention, the content of polyaniline-coated nano-metal oxide in the conductive coating is 15 to 35 parts by weight, such as 17 parts by weight, 19 parts by weight, 21 parts by weight, 23 parts by weight, 25 parts by weight, 27 parts by weight, 29 parts by weight, 31 parts by weight, or 33 parts by weight.

[0014] In this invention, the graphite content in the conductive coating is 15 to 35 parts by weight, such as 17 parts by weight, 19 parts by weight, 21 parts by weight, 23 parts by weight, 25 parts by weight, 27 parts by weight, 29 parts by weight, 31 parts by weight, or 33 parts by weight.

[0015] In this invention, the fluorocarbon resin content in the conductive coating is 30 to 50 parts by weight, for example, 32 parts by weight, 34 parts by weight, 36 parts by weight, 38 parts by weight, 40 parts by weight, 42 parts by weight, 44 parts by weight, 46 parts by weight, or 48 parts by weight.

[0016] In this invention, the content of curing agent in the conductive coating is 3 to 5 parts by weight, for example 3.2 parts by weight, 3.4 parts by weight, 3.6 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.2 parts by weight, 4.4 parts by weight, 4.6 parts by weight or 4.8 parts by weight, etc.

[0017] In this invention, the solvent content in the conductive coating is 30 to 50 parts by weight, for example, 32 parts by weight, 34 parts by weight, 36 parts by weight, 38 parts by weight, 40 parts by weight, 42 parts by weight, 44 parts by weight, 46 parts by weight, or 48 parts by weight.

[0018] Preferably, the polyaniline-coated nano-metal oxide D 50 The particle size is 60–150 nm, such as 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm or 140 nm.

[0019] Preferably, the nano-metal oxide in the polyaniline-coated nano-metal oxide includes any one or a combination of at least two of nano-CuO, nano-Cu2O, nano-ZnO2, or nano-TiO2.

[0020] Preferably, the D of the nano-metal oxide in the polyaniline-coated nano-metal oxide is... 50 The particle size is 50-100nm, such as 60nm, 70nm, 80nm or 90nm.

[0021] Preferably, the raw materials for preparing the polyaniline-coated nano-metal oxide include the following components in parts by weight:

[0022]

[0023] Preferably, the content of aniline in the raw material for preparing the polyaniline-coated nano-metal oxide is 1 to 10 parts by weight, such as 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, or 9 parts by weight.

[0024] Preferably, the content of nano-metal oxide in the raw material for preparing polyaniline-coated nano-metal oxide is 1 to 10 parts by weight, such as 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, or 9 parts by weight.

[0025] Preferably, the hydrochloric acid content in the raw materials for preparing the polyaniline-coated nano-metal oxide is 1 to 20 parts by weight, such as 2 parts by weight, 4 parts by weight, 6 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, 14 parts by weight, 16 parts by weight, or 18 parts by weight.

[0026] Preferably, the initiator content in the raw materials for preparing the polyaniline-coated nano-metal oxide is 5 to 15 parts by weight, such as 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, or 14 parts by weight.

[0027] Preferably, the initiator comprises ammonium persulfate.

[0028] Preferably, the polyaniline-coated nano-metal oxide is obtained by reacting aniline, nano-metal oxide, hydrochloric acid, and an initiator in water.

[0029] Preferably, the preparation method of the polyaniline-coated nano-metal oxide specifically includes the following steps:

[0030] (1) Add aniline, nano-metal oxide and hydrochloric acid to water, mix them evenly under nitrogen protection, and control the temperature at 0-25℃ (e.g. 2℃, 4℃, 6℃, 8℃, 10℃, 12℃, 14℃, 16℃, 18℃, 20℃, 22℃ or 24℃, etc.) to obtain a homogeneous solution;

[0031] (2) Add an initiator and water to the homogeneous solution obtained in step (1) and react for 2 to 12 hours (e.g., 2 hours, 4 hours, 6 hours, 8 hours, 10 hours or 12 hours). After washing, drying and grinding, the polyaniline-coated nano-metal oxide is obtained.

[0032] Preferably, the curing agent comprises any one or a combination of at least two of HDI biuret, HDI trimer, or isophorone diisocyanate (IPDI).

[0033] Preferably, the solvent includes any one or a combination of at least two of ethyl acetate, methyl isobutyl ketone, or n-butanol.

[0034] Preferably, the conductive coating further includes 0.3 to 1 part by weight (e.g., 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9 parts by weight, etc.) of a dispersant.

[0035] Preferably, the dispersant comprises any one or a combination of at least two of the fluorocarbon surfactants FC-4430, FC-4432, or BNK-4020.

[0036] Preferably, the conductive coating further includes 4 to 16 parts by weight (e.g., 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 12 parts by weight, or 14 parts by weight, etc.) of coupling agent.

[0037] Preferably, the coupling agent includes any one or a combination of at least two of coupling agents KH550, KH560, or KH570.

[0038] In a second aspect, the present invention provides a method for preparing a conductive coating as described in the first aspect, the method comprising: mixing polyaniline-coated nano-metal oxide, graphite, optionally a dispersant and optionally a coupling agent in a solvent, adding fluorocarbon resin for further mixing, and then adding a curing agent for further mixing to obtain the conductive coating.

[0039] It should be noted that the preparation method of the conductive coating as described in the first aspect of the present invention does not have special requirements for the mixing temperature, time and stirring speed, as long as the mixing is uniform.

[0040] Thirdly, the present invention provides a conductive coating obtained by curing a conductive coating resistant to soil microbial corrosion as described in the first aspect.

[0041] Preferably, the curing temperature is 20 to 40°C, such as 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C or 38°C, and more preferably room temperature.

[0042] Preferably, the curing time is 20 to 30 hours, such as 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, or 29 hours.

[0043] Fourthly, the present invention provides the application of the conductive coating for resisting soil microbial corrosion as described in the first aspect in the corrosion protection of metal product surfaces.

[0044] Preferably, the metal product includes a metal grounding material.

[0045] Preferably, the metal grounding material includes carbon steel grounding material.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The conductive coating for resisting soil microbial corrosion provided by this invention comprises specific proportions of polyaniline-coated nano-metal oxide, graphite, fluorocarbon resin, curing agent, and solvent. By adding the polyaniline-coated nano-metal oxide and graphite, the conductive coating possesses excellent broad-spectrum resistance to soil microbial corrosion and conductive properties. When applied to the surface of grounding materials, it effectively prevents the grounding materials from being corroded by microorganisms, thereby improving the corrosion resistance and grounding current dissipation of the grounding materials and maximizing the durability of the grounding materials. At the same time, the conductive coating also has advantages such as high adhesion to the substrate, wide range of applications, low cost, simple construction, and environmental friendliness. Detailed Implementation

[0048] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0049] Unless otherwise specified, the raw materials involved in the specific embodiments of this invention are all conventional materials in the art and can be purchased commercially; the instruments and equipment involved are also common instruments and equipment in the art.

[0050] In particular, the following is some information about the raw materials involved in the specific embodiments of the present invention:

[0051] (1) Nano Cu2O: D 50 The particle size is 50 nm;

[0052] (2) Nano CuO: D 50 The particle size is 60 nm;

[0053] (3) Nano TiO2: D 50 The particle size is 60 nm;

[0054] (4) Fluorocarbon resin: purchased from Shanghai Daikin Fluorine Coatings Co., Ltd., model GK570;

[0055] (5) Dispersant: Specifically, a fluorocarbon surfactant dispersant, purchased from Shanghai Xianglan Chemical Co., Ltd., model FC-4430.

[0056] Preparation Example 1

[0057] A polyaniline-coated nano-Cu2O, whose D 50 The particle size is 60 nm, and its preparation method includes the following steps:

[0058] (1) Add 5 parts by weight of aniline, 10 parts by weight of nano Cu2O and 20 parts by weight of hydrochloric acid to 50 parts by weight of water, control the temperature at 0℃, and stir under N2 protection to form a homogeneous solution.

[0059] (2) Add 10 parts by weight of ammonium persulfate and 50 parts by weight of water to the above homogeneous solution and react for 10 h. Filter the solution and wash the resulting filter cake with deionized water until neutral, then wash with ethanol until the filtrate is colorless, and finally wash with ether 3 times. Dry the product in a vacuum oven at room temperature for 24 h and grind it thoroughly to obtain the polyaniline-coated nano-Cu2O.

[0060] Preparation Example 2

[0061] A polyaniline-coated nano-CuO / TiO2, its D 50 The particle size is 70 nm, and its preparation method includes the following steps:

[0062] (1) Add 10 parts by weight of aniline, 0.5 parts by weight of nano CuO, 0.5 parts by weight of nano TiO2 and 1 part by weight of hydrochloric acid to 50 parts by weight of water, control the temperature at 18°C, and stir under N2 protection to form a homogeneous solution.

[0063] (2) Add 5 parts by weight of ammonium persulfate and 50 parts by weight of water to the above homogeneous solution and react for 12 h. Filter the solution and wash the resulting filter cake with deionized water until neutral, then wash with ethanol until the filtrate is colorless, and finally wash with ether twice. Dry the product in a vacuum oven at room temperature for 24 h and grind it thoroughly to obtain the polyaniline-coated nano-CuO / TiO2.

[0064] Preparation Example 3

[0065] A polyaniline-coated nano-CuO, whose D 50 The particle size is 100 nm, and its preparation method includes the following steps:

[0066] (1) Add 1 part by weight of aniline, 5 parts by weight of nano CuO and 1 part by weight of hydrochloric acid to 50 parts by weight of water, control the temperature at 20°C, and stir under N2 protection to form a homogeneous solution.

[0067] (2) Add 15 parts by weight of ammonium persulfate and 50 parts by weight of water to the above homogeneous solution and react for 8 hours. Filter the solution and wash the resulting filter cake with deionized water until neutral, then wash with ethanol until the filtrate is colorless. Finally, wash with ether twice. Dry the product in a vacuum oven at room temperature for 24 hours and grind it thoroughly to obtain the polyaniline-coated nano-CuO.

[0068] Example 1

[0069] A conductive coating resistant to soil microbial corrosion comprises the following components by weight:

[0070]

[0071] In this case, the polyaniline-coated nano-Cu2O was prepared from Preparation Example 1, and the coupling agent was KH550;

[0072] The method for preparing the conductive coating provided in this embodiment includes: mixing and dispersing polyaniline-coated nano-Cu2O, graphite, ethyl acetate, coupling agent and dispersant for 1 hour, slowly adding fluorocarbon resin and stirring for 1.5 hours, and then adding HDI biuret and stirring for 0.5 hours to obtain the conductive coating.

[0073] Example 2

[0074] A conductive coating resistant to soil microbial corrosion comprises the following components by weight:

[0075]

[0076] In this case, the polyaniline-coated nano-CuO / TiO2 was from Preparation Example 2, and the coupling agent was KH570;

[0077] The method for preparing the conductive coating provided in this embodiment includes: mixing and dispersing polyaniline-coated nano-ZnO2, graphite, methyl isobutyl ketone, coupling agent and dispersant for 1 hour, slowly adding fluorocarbon resin and stirring for 1.5 hours, and then adding HDI trimer and stirring for 0.5 hours to obtain the conductive coating.

[0078] Example 3

[0079] A conductive coating resistant to soil microbial corrosion comprises the following components by weight:

[0080]

[0081] In this case, the polyaniline-coated nano-CuO was prepared from Preparation Example 3, and the coupling agent was KH560;

[0082] The method for preparing the conductive coating provided in this embodiment includes: mixing and dispersing polyaniline-coated nano-CuO, graphite, butanol, coupling agent and dispersant for 1 hour, slowly adding fluorocarbon resin and stirring for 1.5 hours, and then adding isophorone diisocyanate and stirring for 0.5 hours to obtain the conductive coating.

[0083] Example 4

[0084] A conductive coating resistant to soil microbial corrosion is disclosed, which differs from Example 1 in that the coupling agent KH550 is not added, while the other substances, dosages, and preparation methods are the same as in Example 1.

[0085] Example 5

[0086] A conductive coating resistant to soil microbial corrosion, which differs from Example 1 in that the amount of polyaniline-coated nano-Cu2O and graphite added in Example 1 is 25 parts by weight, while the other substances, amounts and preparation methods are the same as in Example 1.

[0087] Example 6

[0088] A conductive coating resistant to soil microbial corrosion, which differs from Example 1 in that the amount of polyaniline-coated nano-Cu2O added in Example 1 is 35 parts by weight, the amount of graphite added is 15 parts by weight, and the other substances, amounts and preparation methods are the same as in Example 1.

[0089] Example 7

[0090] A conductive coating resistant to soil microbial corrosion is provided, which differs from Example 2 in that the amount of polyaniline-coated nano-Cu2O / TiO2 and the amount of graphite added in Example 2 are 25 parts by weight, while the other substances, amounts and preparation methods are the same as in Example 2.

[0091] Example 8

[0092] A conductive coating resistant to soil microbial corrosion is provided, which differs from Example 3 in that the amount of polyaniline-coated nano-CuO added in Example 3 is 25 parts by weight, the amount of graphite added is 25 parts by weight, and the other substances, amounts and preparation methods are the same as in Example 3.

[0093] Comparative Example 1

[0094] A conductive coating resistant to soil microbial corrosion is disclosed, which differs from Example 1 in that the amount of polyaniline-coated nano-Cu2O added is 50 parts by weight, and no graphite is added. Other substances, amounts, and preparation methods are the same as in Example 1.

[0095] Comparative Example 2

[0096] A conductive coating resistant to soil microbial corrosion is disclosed, which differs from Example 1 in that the amount of graphite added is 50 parts by weight, and no polyaniline-coated nano-Cu2O is added. All other substances, amounts, and preparation methods are the same as in Example 1.

[0097] Comparative Example 3

[0098] A conductive coating resistant to soil microbial corrosion differs from Example 1 in that the amount of polyaniline-coated nano-Cu2O added is 5 parts by weight, the amount of graphite added is 45 parts by weight, and the other substances, amounts, and preparation methods are the same as in Example 1.

[0099] Comparative Example 4

[0100] A conductive coating resistant to soil microbial corrosion differs from Example 1 in that the amount of polyaniline-coated nano-Cu2O added is 45 parts by weight, the amount of graphite added is 5 parts by weight, and the other substances, amounts, and preparation methods are the same as in Example 1.

[0101] Comparative Example 5

[0102] A conductive coating resistant to soil microbial corrosion is disclosed, which differs from Example 1 in that polyaniline is used instead of polyaniline to coat nano-Cu2O, while the other substances, amounts and preparation methods are the same as in Example 1.

[0103] Comparative Example 6

[0104] A conductive coating resistant to soil microbial corrosion is disclosed, which differs from Example 1 in that nano-Cu2O is used instead of polyaniline to coat nano-Cu2O, while other substances, amounts, and preparation methods are the same as in Example 1.

[0105] Performance testing:

[0106] (1) Adhesion: The conductive coatings obtained in the examples and comparative examples were sprayed onto carbon steel and cured at room temperature for 24 hours to obtain the test samples; the test was carried out according to the test method provided in GB / T 9286-1998 "Cross-cut test of paint and varnish film";

[0107] (2) Volume resistivity: The conductive coatings obtained in the examples and comparative examples were coated on glass slides respectively, and their volume resistivity at 20°C was tested using a four-probe resistance tester.

[0108] (3) Corrosion resistance: The conductive coatings obtained in the examples and comparative examples were sprayed onto carbon steel and cured at room temperature for 24 hours to obtain the test samples. After cleaning and drying, the test samples were placed in a biological clean bench for ultraviolet sterilization. Each material was weighed and three parallel samples were set up. The test samples were then placed in sulfate-reducing bacteria culture medium solution and placed in an anaerobic glove box. After soaking for 15 days, the samples were taken out. After the experiment, the hanging plates were taken out and soaked in an acid removal solution composed of 27.1 mL hydrochloric acid, 0.5 g hexamethylenetetramine and 71.8 mL deionized water. The plates were placed in a high-power CNC ultrasonic cleaner and oscillated at room temperature for 10 min to remove corrosion products. After weighing, the corrosion rate v was calculated according to formula (1). corr (Unit: mm / a), take the average value of 3 hanging pieces;

[0109]

[0110] In equation (1), m is the mass loss (unit: g), and A is the corrosion area of ​​the plate (unit: cm). 2 ), t is the corrosion time (unit: h), and ρ is the density of the coupon.

[0111] The conductive coatings provided in Examples 1-8 and Comparative Examples 1-6 were tested according to the above test methods, and the test results are shown in Table 1.

[0112] Table 1

[0113] Adhesion / Grade Volume resistivity / Ω·cm <![CDATA[Corrosion rate / mm·a -1 > Example 1 0 0.34 0.22 Example 2 0 0.55 0.13 Example 3 0 0.38 0.10 Example 4 1 0.52 0.10 Example 5 1 0.53 0.10 Example 6 1 0.37 0.11 Example 7 1 0.33 0.29 Example 8 1 0.32 0.08 Comparative Example 1 1 2.9 0.17 Comparative Example 2 0 0.70 2.3 Comparative Example 3 2 0.58 1.8 Comparative Example 4 2 2.5 0.18 Comparative Example 5 0 0.45 3.7 Comparative Example 6 0 0.78 0.98

[0114] According to the data in Table 1:

[0115] The conductive coatings provided in Examples 1-3, which resist soil microbial corrosion, all exhibit adhesion to carbon steel up to grade 0, with a volume resistivity of only 0.34-0.55 Ω·cm and a corrosion rate of 0.10-0.22 mm·a. -1 It possesses excellent substrate adhesion, electrical conductivity, and resistance to microbial corrosion.

[0116] Compared with Example 1, the conductive coating provided in Example 4 did not contain a coupling agent, which resulted in a slight decrease in its conductivity and adhesion to the substrate.

[0117] Meanwhile, comparing the data of Examples 1 and 5-6, Examples 2 and 7, and Examples 3 and 8, it can be found that the amount of polyaniline-coated nano-Cu2O and the amount of graphite added also affect the conductivity, substrate adhesion and microbial corrosion resistance of the conductive coating.

[0118] Furthermore, compared to Example 1, the conductive coatings provided in Comparative Examples 1 and 4 either did not contain graphite or had too low a concentration of graphite, resulting in higher volume resistivity and decreased conductivity. The conductive coatings provided in Comparative Examples 2 and 3 either did not contain polyaniline-coated nano-Cu2O or had too low a concentration of polyaniline-coated nano-Cu2O, leading to a faster corrosion rate and decreased resistance to microbial corrosion. In Comparative Example 5, replacing polyaniline-coated nano-Cu2O with polyaniline resulted in a significantly faster corrosion rate and a marked decrease in resistance to microbial corrosion. Similarly, in Comparative Example 6, replacing polyaniline-coated nano-Cu2O with nano-Cu2O also resulted in a faster corrosion rate, increased volume resistivity, and decreased resistance to microbial corrosion and conductivity.

[0119] The applicant declares that this invention illustrates a conductive coating resistant to soil microbial corrosion, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above process steps, meaning that this invention does not necessarily rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A conductive coating resistant to soil microbial corrosion, characterized in that, The conductive coating comprises the following components in parts by weight: 15-35 parts by weight of polyaniline-coated nano-metal oxides; Graphite 15-35 parts by weight; 30-50 parts by weight of fluorocarbon resin; 3-5 parts by weight of curing agent; Solvent 30-50 parts by weight; The nano-metal oxides in the polyaniline-coated nano-metal oxides include any one or a combination of at least two of nano-CuO, nano-Cu2O, or nano-TiO2.

2. The conductive coating according to claim 1, characterized in that, The polyaniline-coated nano-metal oxide D 50 The particle size is 60~150 nm.

3. The conductive coating according to claim 1, characterized in that, The D of the nano-metal oxide in the polyaniline-coated nano-metal oxide 50 The particle size is 50~100 nm.

4. The conductive coating according to claim 1, characterized in that, The raw materials for preparing the polyaniline-coated nano-metal oxides include the following components in parts by weight: 1-10 parts by weight of aniline; 1-10 parts by weight of nano-metal oxides; 1-20 parts by weight of hydrochloric acid; Initiator 5-15 parts by weight.

5. The conductive coating according to claim 4, characterized in that, The initiator includes ammonium persulfate.

6. The conductive coating according to claim 4, characterized in that, The polyaniline-coated nano-metal oxide is obtained by reacting aniline, nano-metal oxide, hydrochloric acid, and an initiator in water.

7. The conductive coating according to claim 1, characterized in that, The curing agent includes any one or a combination of at least two of HDI biuret, HDI trimer, or isophorone diisocyanate.

8. The conductive coating according to claim 1, characterized in that, The solvent includes any one or a combination of at least two of ethyl acetate, methyl isobutyl ketone, or n-butanol.

9. The conductive coating according to claim 1, characterized in that, The conductive coating also includes 0.3 to 1 part by weight of a dispersant.

10. The conductive coating according to claim 1, characterized in that, The conductive coating also includes 4 to 16 parts by weight of coupling agent.

11. The conductive coating according to claim 10, characterized in that, The coupling agent includes any one or a combination of at least two of coupling agents KH550, KH560, or KH570.

12. A method for preparing a conductive coating resistant to soil microbial corrosion as described in any one of claims 1 to 11, characterized in that, The preparation method includes: mixing polyaniline-coated nano-metal oxide, graphite, optionally a dispersant and optionally a coupling agent in a solvent, adding fluorocarbon resin and mixing, and then adding a curing agent and mixing to obtain the conductive coating.

13. A conductive coating, characterized in that, The conductive coating is obtained by curing the conductive coating for resisting soil microbial corrosion as described in any one of claims 1 to 11.

14. The application of a conductive coating resistant to soil microbial corrosion as described in any one of claims 1 to 11 in the corrosion protection of metal product surfaces.

15. The application according to claim 14, characterized in that, The metal products include metal grounding materials.

16. The application according to claim 15, characterized in that, The metal grounding material includes carbon steel grounding material.

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