Preparation method of aluminum material surface cathodic protection type composite conductive anticorrosion coating

Abstract

The application discloses a preparation method of an aluminum material surface cathode protection type composite conductive anticorrosion coating, and specifically comprises the following steps: firstly, preparing magnetic graphene; secondly, electrostatically self-assembling an anode metal and conductive fibers into an anode anticorrosion filler; then, mixing and stirring the filler with a polymer, a silane coupling agent, a curing agent, a defoaming agent and a solvent to obtain a coating; and finally, uniformly spraying the coating in a high magnetic field onto an aluminum sheet and performing high-temperature curing treatment to obtain a super-hydrophobic conductive anticorrosion coating. The super-hydrophobic conductive anticorrosion coating is prepared on the surface of the aluminum material, the conductive anticorrosion coating on the surface of the aluminum material can be obtained, and the synergistic effect of the anode sacrificial filler, the conductive anticorrosion filler, the silane coupling agent and the high-molecular polymer is fully utilized to prepare a directional anticorrosion graphene layer in the coating, so that the coating has excellent conductive and anticorrosion performances. The coating is sprayed onto the surface of the aluminum material, the service life and the application field of the aluminum material are widened, and the coating has application prospects in the fields of aerospace, electronics and electrical appliances, shipbuilding and construction.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment and relates to a preparation method of an antibiotic selective adsorbent. BACKGROUND

[0002] Aluminum is one of the most widely used metals, which has good electrical conductivity, fast heat conduction, light weight, high strength, easy to form and other advantages. However, aluminum has a thin and dense oxide film on its surface in the air, which affects its electrical conductivity. In addition, aluminum has low hardness, poor wear resistance, and is prone to corrosion in humid, acidic and alkaline environments, which affects its application range and service life. Surface treatment of aluminum can overcome its shortcomings, extend its service life and expand its application range, and give it protective and decorative purposes.

[0003] The surface treatment technology of aluminum includes anodic oxidation, electroplating, coating and other methods. For aluminum-based materials used in the electrical field, in addition to the requirement of corrosion resistance, excellent electrical conductivity is also required. At the same time, super-hydrophobic surface can make corrosive substances separate from the surface of aluminum alloy, improving the service life of the coating. However, the existing technology has the disadvantages of poor hydrophobicity, poor corrosion resistance and large surface resistance, so it is necessary to prepare a super-hydrophobic conductive corrosion-resistant coating on the surface of aluminum material.

[0004] Wu et al. (Wu S-K, Yang W, et al. Characterization of MAO+Cu Composite Coatings on Aluminum Alloy. [J]. Coatings. 2021, 11(10): 1172.) prepared a rough and porous Al2O3 ceramic layer on the surface of aluminum alloy by micro-arc oxidation, and then obtained an Al2O3+Cu composite coating by chemical copper plating. The coating has good corrosion resistance, but the Al2O3 separates the conductive Cu layer from the aluminum alloy substrate, reducing the electrical conductivity of the surface.

[0005] Chinese patent "Aluminum Alloy Chemical Conversion Film Forming Liquid and Preparation Method of Conversion Film" (Application No. CN202010414921.8, Publication No. CN111519176A, Publication Date: August 11, 2020) discloses a surface treatment method for improving the corrosion resistance of aluminum alloy. A dense chemical conversion film is prepared on the surface of aluminum alloy by chemical conversion. The corrosion resistance of the aluminum alloy surface is significantly improved, but the method has the problems of high surface resistance after surface treatment and insufficient surface hydrophobicity.

[0006] Chinese patent "A surface treatment method for preventing corrosion of aluminum alloy" (application number: CN201910499107.8, authorization number: CN110129855B, authorization date: 2021.04.27) discloses a surface treatment method for preventing corrosion of aluminum alloy. The surface of the aluminum alloy is treated by anodic oxidation to form an aluminum oxide film, then immersed in a chemical treatment solution to generate a dense film on the surface of the aluminum alloy, and finally sealed with a low surface energy material to further increase the density of the film on the surface of the aluminum alloy. The film on the surface of the sealed aluminum alloy has strong hydrophobicity and can prevent the adsorption of harmful substances and corrosion, but the method has the problem of large resistance of the oxide film.

[0007] Chinese patent "Preparation method of aluminum alloy corrosion-resistant coating" (application number: CN201810863143.3, publication number: CN108624932A, publication date: 2018.10.09) discloses a preparation method of aluminum alloy corrosion-resistant coating. An oxide film is formed by using a boron-sulfuric acid anodic oxidation process, and then a layer of organic-inorganic composite coating is coated on the surface of the oxide film by using a sol-gel method to achieve the purpose of sealing the hole, thereby greatly improving the corrosion resistance, but the method has the problem of large resistance of the oxide film and the organic-inorganic composite coating on its surface. SUMMARY

[0008] The purpose of the present application is to provide a preparation method of aluminum material surface cathodic protection type composite conductive corrosion-resistant coating, which solves the problems of high surface resistance and poor corrosion resistance of the existing aluminum material surface corrosion-resistant coating.

[0009] The technical solution adopted by the present application is a preparation method of aluminum material surface cathodic protection type composite conductive corrosion-resistant coating, which is implemented according to the following steps:

[0010] Step 1, preparation of magnetic graphene;

[0011] The graphene and iron source are added into the desolvent in a molar ratio of 10:1 and ultrasonically dispersed uniformly, then a precipitating agent is added and stirred vigorously, and then poured into a polytetrafluoroethylene liner and reacted at 180℃ for 8h. After magnetic separation and washing, magnetic graphene is obtained.

[0012] Step 2, preparation of anode sacrificial filler:

[0013] The anode metal particle filler is ultrasonically dispersed in a positive charge modified aqueous solution for 5h, and the cathode nanowire is ultrasonically dispersed in a negative charge modified aqueous solution for 5h, and then dried after centrifugation. The modified anode metal particles and cathode nanowires are dispersed in deionized water and stirred, and then stirred in an amino modified solution to obtain an anode sacrificial filler.

[0014] Step 3, preparation of conductive corrosion-resistant coating:

[0015] The magnetic graphene prepared in step 1 and the anode sacrificial filler prepared in step 2 are mixed with a conductive polymer material, a solvent and a silane coupling agent to stir and disperse the filler uniformly, and then a curing agent and a defoaming agent are added to stir uniformly to obtain the conductive anticorrosive coating.

[0016] Step 4, etching and pore making on the aluminum matrix:

[0017] The aluminum material is placed in acetone for ultrasonic cleaning, cleaned with deionized water, then immersed in 10% sulfuric acid solution for 40s, cleaned with deionized water, then immersed in 5% sodium hydroxide solution for 40s, and cleaned with deionized water to obtain an aluminum material with a clean surface and etched and porous.

[0018] Step 5, preparation of a directional conductive coating:

[0019] The conductive anticorrosive coating obtained in step 3 is uniformly sprayed on the surface of the aluminum sheet at a distance of 30 cm from the surface of the aluminum sheet under the action of a strong magnetic field at a certain angle, and a directional conductive coating is obtained after room temperature curing.

[0020] The preferred scheme is:

[0021] In step 1, the iron source is any one of FeCl3·6H2O, FeCl2·4H2O, etc.; and the precipitating agent is any one of urea, sodium acetate, sodium citrate.

[0022] In step 2, the anode protective filler is one of magnesium powder, zinc powder, etc. The cathode nanowire is any one of carbon fiber, silver nanowire, etc. The molar ratio of the anode and cathode fillers is 1:1-5.

[0023] The aspect ratio of the cathode nanowire is 50-100. The positive charge modification solution is any one of 20% PDDA, CTAB aqueous solution, etc., and the negative charge modification solution is any one of 20% PSS, DDS aqueous solution, etc.

[0024] In step 3, the prepared coating consists of the following substances by mass percentage: 1%-5% of magnetic graphene, 1%-5% of anode sacrificial filler, 25%-35% of conductive polymer, 1%-5% of silane coupling agent, 0.5%-1% of curing agent, 0.5%-1% of defoaming agent, 48%-71% of solvent, and the total of the above components is 100%.

[0025] The polymer is any one of polypyrrole, polyaniline, etc., the solvent is any one of ethanol, DMF, DMSO, etc., the silane coupling agent is any one of KH-570, KH-560, KH-580, etc., the curing agent is any one of polyamide, tertiary amine, etc., and the defoaming agent is one of fatty alcohol ethoxylate siloxane, polyether siloxane, etc.

[0026] The curing treatment in step 5 is that the coating obtained in step 3 is uniformly sprayed on the aluminum sheet in a strong magnetic field, and the angle between the magnetic field and the aluminum sheet is 0-90°.

[0027] The preparation method of the aluminum material surface cathodic protection type composite conductive anticorrosion coating has the advantages that the aluminum material surface conductive anticorrosion coating can be obtained, the synergistic effect of the anode sacrificial filler, the conductive anticorrosion filler, the silane coupling agent and the high polymer is fully utilized, the anticorrosion graphene layer in a directional arrangement is prepared in the coating, the coating has excellent conductive and anticorrosion performances at the same time, the coating is sprayed on the aluminum material surface, the service life and the field of the aluminum material are widened, and the aluminum material has wide application prospects in the fields of aerospace, electronics and electrical appliances, shipbuilding and the like. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic diagram of the appearance of the preparation method of the aluminum material surface sacrificial anode conductive anticorrosion coating prepared in the application. DETAILED DESCRIPTION

[0029] The application will be described in detail below in combination with the drawings and specific embodiments.

[0030] Example 1

[0031] The aluminum material surface conductive anticorrosion coating preparation method is specifically implemented according to the following steps:

[0032] Firstly, the graphene and FeCl3·6H2O are sequentially added into the desolvation agent in a molar ratio of 10:1 and are uniformly ultrasonically dispersed, then urea is added, and after vigorous stirring, the mixture is poured into a polytetrafluoroethylene liner and is reacted at 180℃ for 8h, and the magnetic graphene is obtained after magnetic separation and cleaning.

[0033] Then, the magnesium powder particles are ultrasonically dispersed in a 20wt% PDDA aqueous solution for 5h, and the carbon fibers with a length-diameter ratio of 50 are ultrasonically dispersed in a 20wt% DDS aqueous solution for 5h, and after centrifugation, the mixture is dried. The modified anode metal particles and cathode nanowires are dispersed into deionized water in a molar ratio of 1:1 of the anode filler to the cathode filler, and then are stirred in an amino-modified solution of 80% ethanol, 10% deionized water and 10% KH-550 for 15min to obtain the anode sacrificial filler.

[0034] Then, the magnetic graphene prepared in step 1 and the anode sacrificial filler prepared in step 2 are mixed and stirred in a mass ratio of 1%:1%:25% of the magnetic graphene, the anode sacrificial filler, polypyrrole and 71% ethanol and 1% silane coupling agent KH-570 to uniformly disperse the fillers, and then 0.5% polyamide and 0.5% fatty alcohol ethoxysiloxane are added and stirred uniformly to obtain the conductive anticorrosion coating.

[0035] Then the aluminum material is placed in acetone for ultrasonic cleaning, cleaned with deionized water, then immersed in 10% sulfuric acid solution for 40s, cleaned with deionized water, then immersed in 5% sodium hydroxide solution for 40s, and cleaned with deionized water to obtain an aluminum material with a clean surface and etched and porous.

[0036] Finally, the conductive anticorrosive coating obtained in step 3 is uniformly sprayed on the surface of the aluminum sheet at a distance of 30 cm from the surface of the aluminum sheet under the action of a strong magnetic field with an angle of 0° between the magnetic field and the aluminum sheet, and a directional conductive anticorrosive coating is obtained after room temperature curing.

[0037] Example 2

[0038] First, graphene and FeCl2·4H2O are added to the de-solvent in a molar ratio of 10:1 and ultrasonically dispersed, then sodium acetate is added and stirred vigorously, and then poured into a polytetrafluoroethylene liner and reacted at 180°C for 8h, and then separated and cleaned by magnet to obtain magnetic graphene.

[0039] Then the magnesium powder particles are ultrasonically dispersed in a 20% CTAB aqueous solution for 5h, and the carbon fibers with an aspect ratio of 100 are ultrasonically dispersed in a 20% PSS aqueous solution for 5h, and then dried after centrifugation. The modified anode metal particles and cathode nanowires are dispersed in deionized water in a molar ratio of 1:5, then stirred in an amino-modified solution of 60% ethanol, 20% deionized water, and 20% KH-550, and then soaked for 30min to obtain an anode sacrificial filler.

[0040] Then, the magnetic graphene prepared in step 1 is mixed with the anode sacrificial filler prepared in step 2 in a mass ratio of 5%:5%:35% polyaniline, 48% DMF, and 5% silane coupling agent KH-580, and then stirred to disperse the fillers uniformly, and then 1% tertiary amine and 1% polyether siloxane are added and stirred uniformly to obtain a conductive anticorrosive coating.

[0041] Then the aluminum material is placed in acetone for ultrasonic cleaning, cleaned with deionized water, then immersed in 10% sulfuric acid solution for 40s, cleaned with deionized water, then immersed in 5% sodium hydroxide solution for 40s, and cleaned with deionized water to obtain an aluminum material with a clean surface and etched and porous.

[0042] Finally, the conductive anticorrosive coating obtained in step 3 is uniformly sprayed on the surface of the aluminum sheet at a distance of 30 cm from the surface of the aluminum sheet under the action of a strong magnetic field with an angle of 90° between the magnetic field and the aluminum sheet, and a directional conductive coating is obtained after room temperature curing.

[0043] Example 3

[0044] Firstly, graphene and FeCl2·4H2O were added into the solvent-free medium in a molar ratio of 10:1 and ultrasonically dispersed, then sodium citrate was added and stirred vigorously, and then poured into a polytetrafluoroethylene liner and reacted at 180°C for 8h, and then separated and cleaned by a magnet to obtain magnetic graphene.

[0045] Then, the zinc powder particles were ultrasonically dispersed in a 20% PDDA aqueous solution for 5h, and the silver nanofiber with an aspect ratio of 50 was ultrasonically dispersed in a 20% DDS aqueous solution for 5h, and then dried after centrifugation. The modified anode metal particles and cathode nanowires were dispersed in deionized water in a molar ratio of 1:3, then stirred in an amino-modified solution of 80% ethanol, 10% deionized water and 10% KH-550, and then soaked for 30min to obtain an anode sacrificial filler.

[0046] Then, the magnetic graphene prepared in step 1 was mixed with the anode sacrificial filler prepared in step 2 in a mass ratio of 3%:3%:35% polyaniline, 53% DMF and 4% silane coupling agent KH-580, and then stirred to disperse the fillers uniformly, and then 1% tertiary amine and 1% polyether siloxane were added and stirred uniformly to obtain a conductive corrosion-resistant coating.

[0047] Then, the aluminum material was ultrasonically cleaned in acetone, then cleaned with deionized water, then soaked in a 10% sulfuric acid solution for 40s, then cleaned with deionized water, then soaked in a 5% sodium hydroxide solution for 40s, and then cleaned with deionized water to obtain an aluminum material with a clean surface and etched pores.

[0048] Finally, the conductive corrosion-resistant coating obtained in step 3 was uniformly sprayed on the surface of the aluminum sheet under the action of a strong magnetic field with an angle of 45° between the magnetic field and the aluminum sheet at a distance of 30cm from the surface of the aluminum material, and then cured at room temperature to obtain a directional conductive coating.

[0049] Example 4

[0050] Firstly, graphene and FeCl3·6H2O were added into the solvent-free medium in a molar ratio of 10:1 and ultrasonically dispersed, then sodium citrate was added and stirred vigorously, and then poured into a polytetrafluoroethylene liner and reacted at 180°C for 8h, and then separated and cleaned by a magnet to obtain magnetic graphene.

[0051] Then, the zinc powder particles were ultrasonically dispersed in a 20% PDDA aqueous solution for 5h, and the silver nanofiber with an aspect ratio of 50 was ultrasonically dispersed in a 20% PSS aqueous solution for 5h, and then dried after centrifugation. The modified anode metal particles and cathode nanowires were dispersed in deionized water in a molar ratio of 1:3, then stirred in an amino-modified solution of 60% ethanol, 20% deionized water and 20% KH-550, and then soaked for 30min to obtain an anode sacrificial filler.

[0052] Then, according to the mass ratio, 3% of the magnetic graphene prepared in step 1 and 3% of the anode sacrificial filler prepared in step 2 are mixed with 35% polyaniline, 53% DMF and 4% silane coupling agent KH-580 and stirred to disperse the filler evenly. Then, 1% tertiary amine and 1% fatty alcohol ethoxysiloxane are added and stirred evenly to obtain a conductive anti-corrosion coating.

[0053] Next, the aluminum material is ultrasonically cleaned in acetone, then cleaned with deionized water and immersed in 10% sulfuric acid solution for 40 seconds. After cleaning with deionized water, it is immersed in 5% sodium hydroxide solution for 40 seconds. After cleaning with deionized water, the aluminum material with a clean surface and etched holes is obtained.

[0054] Finally, the conductive anti-corrosion coating obtained in step 3 is uniformly sprayed onto the surface of the aluminum sheet at a distance of 30cm under the action of a strong magnetic field with an angle of 45° between the magnetic field and the aluminum sheet. After curing at room temperature, a directional conductive coating is obtained.

[0055] Table 1 shows the hydrophobic angle, surface contact resistance, and mass loss rate of aluminum materials with coatings in Example 1, coatings in Example 3, chemical conversion films, and conventional untreated aluminum materials.

[0056]

[0057] As shown in Table 1, the untreated aluminum material exhibits the highest surface contact resistance and the greatest mass loss rate. The presence of the oxide film reduces its conductivity and corrosion resistance. In contrast, the aluminum material with a chemical conversion coating shows improved corrosion resistance and conductivity compared to the untreated material. However, its small water contact angle allows corrosive liquids to remain on the surface for extended periods, negatively impacting its long-term corrosion resistance. In Example 1, the graphene nanosheets are exposed on the surface and have undergone hydrophobic modification, exhibiting superhydrophobicity. Simultaneously, the anolyte metal powder and cathode fiber are in contact, forming a sacrificial anode protection system. Furthermore, the magnetic graphene, oriented under a magnetic field, not only increases the path for corrosive substances to penetrate the coating, improving corrosion resistance, but the carbon fibers and graphene also construct a conductive network exhibiting good conductivity. Therefore, the coating in Example 1 demonstrates excellent conductivity and corrosion resistance.

[0058] Depend on Figure 1 It can be seen that the zinc powder at the anode is uniformly distributed on the carbon fiber at the cathode to form a sacrificial anode filler, and the conductive filler graphene is oriented parallel to the aluminum substrate under the action of a magnetic field and forms a conductive network within the coating. At the same time, there are a large number of pores on the surface of the aluminum substrate, which are tightly bonded to the coating.

Claims

1. A method for producing an aluminum material surface cathodically protected composite conductive anticorrosive coating, characterized by, The specific steps are as follows: Step 1, preparation of magnetic graphene The graphene and iron source are added into the desolvation agent in a molar ratio of 10:1 and ultrasonically dispersed, then a precipitating agent is added and stirred vigorously, and then poured into a polytetrafluoroethylene liner and reacted at 180℃ for 8h, and then separated and washed by a magnet to obtain magnetic graphene; Step 2, preparation of anode sacrificial filler The anode metal particle filler is ultrasonically dispersed in a positive charge modified aqueous solution for 5h, and the cathode nanowire is ultrasonically dispersed in a negative charge modified aqueous solution for 5h, and then dried after centrifugation; the modified anode metal particle and cathode nanowire are dispersed in deionized water and stirred, and then placed in an amino modified solution and stirred to obtain an anode sacrificial filler; The anode metal particle filler is one of magnesium powder and zinc powder, the cathode nanowire is any one of carbon fiber and silver nanowire, and the molar ratio of the anode and cathode fillers is 1:1-5; The length-diameter ratio of the cathode nanowire is 50-100, the positive charge modified solution is any one of 20% PDDA and CTAB aqueous solution, and the negative charge modified solution is any one of 20% PSS and DDS aqueous solution; Step 3, preparation of conductive anticorrosive coating The magnetic graphene prepared in step 1 and the anode sacrificial filler prepared in step 2 are mixed with conductive polymer material, solvent and silane coupling agent to disperse the fillers uniformly, and then a curing agent and a defoaming agent are added and stirred uniformly to obtain a conductive anticorrosive coating; Step 4, etching and pore forming of aluminum matrix The aluminum material is ultrasonically cleaned in acetone, cleaned with deionized water, immersed in 10% sulfuric acid solution for 40s, cleaned with deionized water, immersed in 5% sodium hydroxide solution for 40s, and then cleaned with deionized water to obtain an aluminum material with clean surface and etched and formed pores; Step 5, preparation of directional conductive coating The conductive anticorrosive coating obtained in step 2 is uniformly sprayed on the surface of the aluminum sheet at a distance of 30cm from the surface of the aluminum sheet under the action of a strong magnetic field at a certain angle, and a directional conductive coating is obtained after room temperature curing.

2. The production method according to claim 1, characterized by, The iron source in step 1 is any one of FeCl3·6H2O and FeCl2·4H2O, and the precipitating agent is any one of urea, sodium acetate and sodium citrate.

3. The preparation method according to claim 1, characterized in that, The amino modified solution in step 2 is composed of the following substances by volume percentage: ethanol 60-80%, deionized water 10-20%, and KH-550 10-20%; stirring and soaking for 15-30min.

4. The production method according to claim 1, characterized by, The prepared coating in step 3 is composed of the following substances by mass percentage: magnetic graphene 1%-5%, anode sacrificial filler 1%-5%, conductive polymer material 25%-35%, silane coupling agent 1%-5%, curing agent 0.5%-1%, defoaming agent 0.5%-1%, solvent 48%-71%, and the total of the above components is 100%.

5. The preparation method according to claim 4, characterized in that, The conductive polymer material is any one of polypyrrole and polyaniline, the solvent is any one of ethanol, DMF and DMSO; the silane coupling agent is any one of KH-570, KH-560 and KH-580; the curing agent is any one of polyamide and tertiary amine, and the defoaming agent is one of fatty alcohol ethoxylate siloxane and polyether siloxane.

6. The preparation method according to claim 1, characterized in that, The solidification treatment in step 5 is that the coating obtained in step 3 is uniformly sprayed on the aluminum sheet in a strong magnetic field, and the angle between the magnetic field and the aluminum sheet is 0-90°.

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