Aluminum veneer long-acting anti-corrosion process based on nano-composite coating and preparation method thereof

Abstract

The invention discloses an aluminum veneer long-acting anti-corrosion process based on a nano-composite coating, a nano-composite coating material is processed to the surface of an aluminum veneer through the steps of aluminum veneer surface pretreatment, nano-composite coating preparation and coating curing, and the nano-composite coating material adopted for coating of the coating is an environment-friendly material. No harmful substance is generated in the preparation process, and the preparation method is environment-friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum veneer processing, and in particular relates to a long-term anti-corrosion process for aluminum veneers based on a nano-composite coating and a preparation method thereof. Background Art

[0002] Aluminum veneer, a lightweight and easily processed metal material, is widely used in architectural decoration, aerospace, transportation, and other fields. However, aluminum veneer is susceptible to corrosion in humid and corrosive environments, resulting in a shortened service life and reduced performance. Traditional anti-corrosion treatment methods, such as anodizing and electroplating, can improve the corrosion resistance of aluminum veneer to a certain extent, but they are complex, costly, and environmentally polluting. Summary of the Invention

[0003] To solve the above problems, the present invention provides a long-term anti-corrosion process for aluminum veneer based on nanocomposite coating, comprising the following steps: S1. Surface pretreatment of aluminum veneer: Clean and passivate the aluminum veneer to remove surface oil and dust and form a dense oxide film; S2. Preparation of Nanocomposite Coatings: Nanoparticles with excellent corrosion resistance are combined with a resin matrix to prepare nanocomposite coatings. S3 coating: the prepared nanocomposite coating is evenly coated on the surface of the pretreated aluminum veneer by spraying, brushing, etc.; S4. Coating curing: The aluminum veneer coated with the nanocomposite coating is cured at a certain temperature so that the resin matrix in the coating is fully cross-linked and cured to form a stable coating structure.

[0004] Preferably, the nanoparticles are carbon nanotubes (CNTs) or nanoalumina (Al2O3), or a combination of the two, and the particle size or diameter of the nanoparticles is within the range of 20-100 nm.

[0005] Preferably, the resin matrix is ​​epoxy resin, acrylic resin or a combination of the two.

[0006] Preferably, the preparation process of the nanocomposite coating further includes surface modification of the nanoparticles to improve the compatibility and dispersibility of the nanoparticles with the resin matrix.

[0007] Preferably, the cleaning step in the surface pretreatment of the aluminum veneer is performed using chemical cleaning agents, and the passivation treatment step is performed using a chromate solution or a phosphate solution.

[0008] Preferably, the curing temperature in the coating curing step is 80-150° C., and the curing time is 1-3 hours.

[0009] Aluminum veneer based on nano-composite coating Long-term anti-corrosion aluminum veneer, the surface of the aluminum veneer is coated with a layer of nano-composite coating, which has excellent corrosion resistance and long-term anti-corrosion performance.

[0010] Preferably, the thickness of the nanocomposite coating is 10-50 μm.

[0011] The beneficial effects of the present invention are: The nanoparticles in the nanocomposite coating can form a dense barrier layer in the coating, effectively preventing the penetration of corrosive media, thereby significantly improving the corrosion resistance of the aluminum veneer and extending its service life; The preparation method has simple process and convenient operation and is suitable for large-scale production application. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the specific embodiments of the invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1 It is a schematic flow chart of the long-term anti-corrosion process of aluminum veneer of the present invention. DETAILED DESCRIPTION

[0014] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Example

[0015] Aluminum veneer surface pretreatment: Cleaning: Aluminum veneer sheets measuring 1000mm x 1000mm x 2mm were used as the substrate. Acetone was first used to clean the surface of the aluminum veneer to remove oil, dust, and other impurities. Ultrasonic cleaning was used to assist in the cleaning process. The cleaning time was 10 minutes at room temperature.

[0016] Passivation: Place the cleaned aluminum sheet in a chromate solution for passivation. The concentration of the chromate solution is 50g / L, the treatment temperature is 40°C, and the treatment time is 15 minutes. After passivation, rinse the aluminum sheet surface with deionized water to remove any residual chromate solution, and then allow to air dry.

[0017] Nanocomposite coating preparation: Nanoparticle surface modification: Carbon nanotubes (CNTs) with a diameter of 20-50 nm and a length of 5-15 μm are selected as nanoparticles. The CNTs are refluxed in concentrated nitric acid for 2 hours, then washed with deionized water until neutral, and dried to obtain modified CNTs. This modification improves the compatibility and dispersibility of the CNTs in the resin matrix.

[0018] Coating Preparation: Modified CNTs were mixed with epoxy resin E-51 at a mass ratio of 1:10. A high-speed blender was used for stirring at 2000 rpm for 30 minutes to ensure uniform dispersion of the CNTs in the epoxy resin. An appropriate amount of curing agent (such as polyamide) was then added, and stirring was continued for 10 minutes to obtain a nanocomposite coating.

[0019] Coating: The prepared nanocomposite coating is evenly applied to the pretreated aluminum veneer surface by spraying. During the spraying process, the distance between the spray gun and the aluminum veneer surface is maintained at 20-30 cm, the spraying pressure is 0.3-0.5 MPa, and the spraying speed is 0.5-1 m / s. After spraying, the coating thickness on the aluminum veneer surface is approximately 20 μm.

[0020] Coating curing: The aluminum veneer coated with the nanocomposite coating was placed in an oven at 80°C for 2 hours, then heated to 120°C for another hour. During the curing process, the oven was well ventilated to ensure that the curing agent reacted fully and the resin matrix in the coating was fully cross-linked and cured to form a stable coating structure. Example

[0021] Surface pretreatment of aluminum veneer: Same as in Example 1, an aluminum veneer with a size of 1000 mm × 1000 mm × 2 mm was selected as the substrate and cleaned and passivated.

[0022] Nanocomposite coating preparation: Nanoparticle surface modification: Nanoalumina (Al2O3) with a particle size of 50-100 nm was selected as the nanoparticles. The nanoalumina was placed in an ethanol solution and surface modified with an appropriate amount of silane coupling agent. The treatment lasted for 2 hours at 60°C. After modification, the nanoalumina was washed with deionized water and dried for later use.

[0023] Coating Preparation: Mix the modified nano-alumina and epoxy resin E-51 in a mass ratio of 1:8. Stir the mixture in a high-speed blender at 2000 rpm for 30 minutes. Add an appropriate amount of curing agent and continue stirring for 10 minutes to obtain a nanocomposite coating.

[0024] Coating: As in Example 1, the prepared nanocomposite coating is evenly coated on the surface of the pretreated aluminum veneer by spraying. After spraying, the coating thickness on the surface of the aluminum veneer is about 25 μm.

[0025] Coating curing: As in Example 1, the aluminum single plate coated with the nanocomposite coating was placed in an oven at 80° C. for curing for 2 hours, and then the temperature was raised to 120° C. for further curing for 1 hour to fully cure the coating.

[0026] Performance Testing The corrosion resistance of the aluminum veneers prepared in Example 1 and Example 2 was tested. The test method is: the aluminum veneer is immersed in a 3.5% NaCl solution, and the surface corrosion conditions are tested after immersion for 10 days, 20 days, and 30 days respectively. The test results show that: after immersion for 10 days, the aluminum veneer prepared in Example 1 showed only slight signs of corrosion on the surface; after immersion for 20 days, the signs of corrosion increased slightly, but the overall condition remained good; after immersion for 30 days, there was no obvious sign of corrosion on the surface, showing excellent corrosion resistance. After immersion for 10 days and 20 days, the aluminum veneer prepared in Example 2 showed no obvious signs of corrosion on the surface; after immersion for 30 days, only slight corrosion appeared on the edge, and the overall corrosion resistance was also excellent.

[0027] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A long-term anti-corrosion process for aluminum veneer based on nanocomposite coating, characterized by: The following steps are involved: S1. Surface pretreatment of aluminum veneer: Clean and passivate the aluminum veneer to remove surface oil and dust and form a dense oxide film; S2. Preparation of Nanocomposite Coatings: Nanoparticles with excellent corrosion resistance are combined with a resin matrix to prepare nanocomposite coatings. S3 coating: the prepared nanocomposite coating is evenly coated on the surface of the pretreated aluminum veneer by spraying, brushing, etc.; S4. Coating curing: The aluminum veneer coated with the nanocomposite coating is cured at a certain temperature so that the resin matrix in the coating is fully cross-linked and cured to form a stable coating structure.

2. The long-term anti-corrosion process for aluminum veneer based on nanocomposite coating according to claim 1 is characterized by: The nanoparticles are one or a combination of carbon nanotubes (CNTs) or nanoaluminum oxide (Al2O3), and the particle size or diameter of the nanoparticles is within the range of 20-100 nm.

3. The long-term anti-corrosion process for aluminum veneer based on nanocomposite coating according to claim 1 is characterized in that: The resin matrix is ​​one of epoxy resin and acrylic resin or a combination of the two.

4. The long-term anti-corrosion process for aluminum veneer based on nanocomposite coating according to claim 1 is characterized in that: The preparation process of the nanocomposite coating also includes surface modification of the nanoparticles to improve the compatibility and dispersibility of the nanoparticles with the resin matrix.

5. The long-term anti-corrosion process for aluminum veneer based on nanocomposite coating according to claim 1 is characterized in that: The cleaning step in the aluminum single plate surface pretreatment adopts chemical cleaning, and the passivation treatment step adopts chromate solution or phosphate solution.

6. The long-term anti-corrosion process for aluminum veneer based on nanocomposite coating according to claim 1 is characterized in that: The curing temperature in the coating curing step is 80-150° C., and the curing time is 1-3 hours.

7. Long-term anti-corrosion aluminum veneer based on nano-composite coating, characterized by: The aluminum veneer is prepared by the long-term anti-corrosion process based on nano-composite coating according to any one of claims 1 to 6. The surface of the aluminum veneer is coated with a layer of nano-composite coating, which has excellent corrosion resistance and long-term anti-corrosion performance.

8. The long-lasting anti-corrosion aluminum veneer based on nanocomposite coating according to claim 7 is characterized in that: The thickness of the nanocomposite coating is 10-50 μm.

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