Surface treatment method for aluminum alloy with fluorescent layer and aluminum alloy workpiece

Abstract

The invention relates to the technical field of material surface treatment, and discloses a surface treatment method for an aluminum alloy with a fluorescent layer and an aluminum alloy workpiece. The surface treatment method for the aluminum alloy with the fluorescent layer comprises the following steps that S1, an aluminum alloy matrix is subjected to anodic oxidation treatment, and a porous anodic oxidation film is formed on the surface of the aluminum alloy matrix; s2, fluorescent ink is locally sprayed on the surface of the porous anodic oxide film, curing is carried out, a local fluorescent layer is formed, and the area where the fluorescent ink is not sprayed is a non-fluorescent area; s3, performing global dyeing on the porous anodic oxide film of the local fluorescent layer and the non-fluorescent region, and drying to form a global covered dyeing layer; and S4, hole sealing is conducted, a hole sealing layer covering the whole area is formed on the dyeing layer, and the aluminum alloy workpiece is prepared. When the UV lamp irradiates, fluorescent patterns are shown on the aluminum alloy workpiece, so that the functions of identity information recognition and counterfeiting prevention are achieved, and the aluminum alloy workpiece is excellent in corrosion resistance and wear resistance and meets the subdivision requirements in the fields of industry, consumption, safety and the like.

Description

Technical Field

[0001] This application relates to the field of material surface treatment technology, and in particular to a method for surface treatment of aluminum alloy with a fluorescent layer and an aluminum alloy workpiece. Background Technology

[0002] Aluminum alloys, with their high strength, low density, and ease of processing, are widely used in the field of exterior components for consumer electronics. As the consumer electronics market continues to develop, consumers' demands for product appearance are also increasing, with the color and surface finish of exterior components becoming crucial factors in attracting consumers. The extensive use of aluminum alloys in electronic product exterior components not only meets the product's requirements for strength and processing performance but also provides a foundation for the diversification of product appearance.

[0003] In existing technologies, anodizing and immersion dyeing processes are commonly used to achieve different colors on aluminum alloy workpieces. Anodizing forms an oxide film on the surface of the aluminum alloy using an electrochemical method, which improves the corrosion resistance and wear resistance of the aluminum alloy. Immersion dyeing involves immersing the anodized aluminum alloy product in a dyeing solution, allowing the color to adhere to the oxide film. In this way, aluminum alloys can achieve single-color or segmented two-color effects. In addition, other surface treatment processes, such as spraying and electroplating, are also used to improve the surface finish of aluminum alloy workpieces.

[0004] However, these processing techniques still have obvious drawbacks. The surface effects they produce are relatively simple. Whether it is anodizing, dyeing, spraying, or electroplating, it is difficult to achieve complex and varied patterns and rich color effects. Moreover, these surface effects are highly replicable, making it difficult to meet the needs of consumer electronics products for unique appearance and personalized design. Summary of the Invention

[0005] To at least overcome one of the problems existing in the prior art, one objective of this application is to provide a surface treatment method for aluminum alloys with a fluorescent layer. This method uses aluminum alloy as a substrate and, through steps such as anodizing, localized spraying of fluorescent ink, dyeing, and sealing, sequentially forms a porous anodized layer, a localized fluorescent layer, a fully covered dyeing layer, and a sealing layer on the aluminum alloy workpiece from the substrate surface outwards. Without UV light irradiation, the aluminum alloy workpiece does not fluoresce; when irradiated with UV light, a fluorescent pattern appears on the aluminum alloy workpiece, thereby serving as an identification feature and preventing counterfeiting, adapting to the segmented needs of various fields such as industry, consumer goods, and security. A second objective of this application is to provide the aforementioned aluminum alloy workpiece.

[0006] Therefore, this application adopts the following technical solution: The first aspect of this application provides a method for surface treatment of aluminum alloy with a fluorescent layer, comprising the following steps: S1. The aluminum alloy substrate is anodized to form a porous anodized film on the surface of the aluminum alloy substrate. S2. Spray fluorescent ink onto the surface of the porous anodic oxide film locally, cure it to form a local fluorescent layer, and the area where fluorescent ink is not sprayed is a non-fluorescent area. S3. The porous anodic oxide film in the local fluorescent layer and the non-fluorescent area is stained and dried to form a stained layer that covers the entire area. S4. Perform sealing to form a sealing layer that covers the entire area on the dyed layer, and obtain the aluminum alloy workpiece.

[0007] In this application's method for surface treatment of aluminum alloys with a fluorescent layer, step S1 involves anodizing the aluminum alloy substrate to form a porous anodic oxide film on its surface. This oxide film effectively isolates the aluminum alloy from contact with corrosive media, improving its corrosion resistance. Simultaneously, the porous structure of the oxide film facilitates the adsorption and penetration of substances such as inks and dyes in subsequent processing steps. Step S2 involves locally spraying fluorescent ink onto the porous anodic oxide film surface and curing it to form a localized fluorescent layer. This gives the aluminum alloy workpiece a unique visual effect, suitable for applications such as decoration and marking. Furthermore, the presence or absence of fluorescence can be used to determine the surface characteristics of the workpiece. The process involves several steps: Step S3 involves dyeing and drying the porous anodic oxide film in the local fluorescent and non-fluorescent areas to form a fully covered dyeing layer. This further enhances the decorative properties of the aluminum alloy workpiece, meets different color requirements, and also strengthens the protection of the aluminum alloy substrate to a certain extent. Step S4 involves sealing the holes, forming a fully covered sealing layer on the dyeing layer. This seals the pores of the anodic oxide film, preventing corrosive media and moisture from entering the pores, thereby further improving the corrosion resistance and wear resistance of the aluminum alloy workpiece, enhancing its protective performance, and extending its service life.

[0008] Preferably, in step S1, the aluminum alloy substrate undergoes a pre-anodization treatment before the anodizing process.

[0009] Preferably, in step S1, the anodizing pretreatment includes degreasing, alkaline etching, neutralization, and chemical polishing processes.

[0010] Preferably, in step S1, the degreasing is performed using acidic degreasing water with a mass concentration of 10%, the degreasing temperature is 80~90℃, and the degreasing time is 2~3 minutes.

[0011] Preferably, in step S1, the alkaline etching uses a sodium hydroxide aqueous solution with a concentration of 50~70g / L, the alkaline etching temperature is 50~70℃, and the alkaline etching time is 30~40s.

[0012] Preferably, in step S1, the neutralization is carried out at room temperature using a 15% sulfuric acid solution, and the neutralization time is 10-15 seconds.

[0013] Preferably, in step S1, the chemical polishing uses a mixed solution of sulfuric acid with a mass concentration of 25% and phosphoric acid with a mass concentration of 75% as the polishing liquid, the temperature of the chemical polishing is 95~105℃, and the time of the chemical polishing is 40~50s.

[0014] Preferably, in step S1, the anodizing temperature is 19~23℃, the anodizing voltage is 12~16V, and the anodizing time is 50~60min. More preferably, in step S1, the anodizing temperature is 19~23℃, the anodizing voltage is 14~16V, and the anodizing time is 55~60min.

[0015] In step S1, the anodizing solution is a sulfuric acid solution with a mass concentration of 15%~20%, the temperature is 19~23℃, the voltage is 12~16V, and the time is 50~60min. These specific parameter ranges ensure the formation of a high-quality porous anodized film on the aluminum alloy substrate surface. Excessively high or low temperatures may lead to unstable oxide film growth rates and uneven film structure; inappropriate voltage may affect the thickness and hardness of the oxide film; furthermore, too short anodizing time results in insufficient oxide film thickness and corrosion resistance, while too long a time may lead to energy waste and excessive film growth, affecting subsequent processing.

[0016] Preferably, in step S2, the spraying is performed using an inkjet printer, the nozzle diameter of which is ≤0.1mm, and the spraying amount is 15~25g / m2. More preferably, in step S2, the spraying is performed using an inkjet printer, the nozzle diameter of which is ≤0.1mm, and the spraying amount is 18~25g / m2.

[0017] Preferably, in step S2, the curing temperature is 35~45℃ and the curing time is 15~20min. More preferably, in step S2, the curing temperature is 40~45℃ and the curing time is 15~18min.

[0018] Preferably, in step S2, a settling period of 10-20 minutes is included before curing. Preferably, in step S2, a settling period of 15-20 minutes is included before curing.

[0019] In step S2, spraying is performed using an inkjet printer with a nozzle diameter of less than 0.1 mm. This smaller nozzle diameter facilitates finer spraying, accurately forming localized fluorescent areas on the porous anodic oxide film surface, thus improving the precision and clarity of the pattern. The spraying amount is 15-25 g / m², ensuring a uniform coating of fluorescent ink on the anodic oxide film surface. This prevents excessive ink from causing dripping or accumulation, while insufficient ink avoids affecting the fluorescent effect. Curing at 35-45℃ for 15-20 minutes allows for the full reaction of film-forming agents and other components in the fluorescent ink, forming a strong fluorescent layer and ensuring its adhesion and durability. Excessive temperature may cause decomposition or deterioration of ink components, affecting the fluorescent effect and coating quality; insufficient temperature results in incomplete curing and unstable coating performance. In step S2, before curing, there is a settling period of 10-20 minutes. This settling period allows the fluorescent ink sprayed on the porous anodic oxide film surface to have enough time to level out, fill the pores, make the fluorescent layer more uniform, and reduce defects on the coating surface.

[0020] Preferably, in step S2, the fluorescent ink includes fluorescent pigment, film-forming agent, dispersant, leveling agent, defoamer, filler and solvent.

[0021] Preferably, the fluorescent pigment is selected from at least one of fluorescent yellow, fluorescent orange, fluorescent red, and fluorescent green. More preferably, the fluorescent pigment is selected from at least one of fluorescent yellow, fluorescent orange, and fluorescent red.

[0022] Preferably, the film-forming agent is selected from at least one of waterborne polyurethane resin, hydroxyl acrylic resin, and acrylic-polyurethane copolymer resin. More preferably, the film-forming agent is selected from at least one of waterborne polyurethane resin and hydroxyl acrylic resin.

[0023] Preferably, the dispersant is selected from at least one of BYK-110, BYK-163, and TEGO Dispers 750W. More preferably, the dispersant is selected from at least one of BYK-110 and TEGO Dispers 750W.

[0024] Preferably, the leveling agent is selected from at least one of BYK-306, TEGO Glide 410, and BYK-358N. More preferably, the leveling agent is selected from at least one of BYK-306 and TEGO Glide 410.

[0025] Preferably, the defoamer is selected from at least one of BYK-066N, Defom 6800, and Colloid 640. More preferably, the defoamer is selected from at least one of BYK-066N and Colloid 640.

[0026] Preferably, the filler is fumed silica or wollastonite powder.

[0027] Preferably, the solvent is ethyl acetate or butyl acetate.

[0028] Preferably, in step S2, the weight ratio of the fluorescent pigment, film-forming agent, dispersant, leveling agent, defoamer, filler and solvent is (25~35):(40~50):(1~3):(2~4.3):(0.2~0.5):(0.1~0.8):(35~40).

[0029] In step S2, the fluorescent ink includes fluorescent pigments, film-forming agents, dispersants, leveling agents, defoamers, fillers, and solvents. The fluorescent pigments provide the fluorescent effect; the film-forming agent primarily forms a continuous film layer and fixes the fluorescent pigments and other components onto the surface of the anodic oxide film; the dispersant ensures that the solid particles, such as the fluorescent pigments, are uniformly dispersed in the solvent, preventing agglomeration; the leveling agent helps the ink form a smooth and even coating on the anodic oxide film surface; the defoamer eliminates air bubbles in the ink, preventing them from forming defects in the coating; the filler helps improve the hardness of the coating; and the solvent dissolves and dilutes other components and adjusts the viscosity of the ink. These components work together to form a uniform, strongly adherent fluorescent layer.

[0030] Preferably, in step S3, the staining is immersion staining, the immersion staining time is 2-3 minutes, the drying temperature is 90-105°C, and the drying time is 10-20 minutes. More preferably, in step S3, the staining is immersion staining, the immersion staining time is 2.5-3 minutes, the drying temperature is 95-105°C, and the drying time is 15-20 minutes.

[0031] In step S3, the immersion dyeing process allows the dye to penetrate evenly into the pores of the anodic oxide film and the surface of the fluorescent and non-fluorescent areas. The dye is fully adsorbed and fixed, making the color of the dyed layer uniform and firm, while avoiding over-dyeing that could lead to excessively dark colors or other quality problems.

[0032] Preferably, in step S4, the sealing temperature is 85~95℃, and the sealing time is 30~45min. More preferably, in step S4, the sealing temperature is 90~95℃, and the sealing time is 35~45min.

[0033] In step S4, a sealing temperature of 85-95℃ and a sealing time of 35-45 minutes allow the sealing agent to fully exert its effect, forming a dense sealing layer on the dyed layer. Excessive temperature may cause the sealing agent to over-react, affecting the sealing effect; excessively low temperature will prevent the sealing agent from fully penetrating and reacting; a sealing time that is too short may result in incomplete pore sealing, affecting the corrosion resistance of the aluminum alloy workpiece; and a sealing time that is too long may have a certain impact on the dyed layer.

[0034] The second aspect of this application provides an aluminum alloy workpiece prepared by a surface treatment method for an aluminum alloy with a fluorescent layer according to the first aspect of this application. The aluminum alloy workpiece uses an aluminum alloy as a substrate, and a porous anodized layer, a local fluorescent layer, a fully covered dyeing layer, and a sealing layer are formed sequentially from the surface of the substrate outward. The total thickness of the porous anodized layer, the local fluorescent layer, the dyeing layer, and the sealing layer is 10.5~15.9µm, and the thickness of the local fluorescent layer is 2~4µm.

[0035] This specific structure and thickness distribution enable aluminum alloy workpieces to have excellent comprehensive performance. The porous anodized layer provides a certain degree of corrosion resistance and a basis for subsequent processing; the local fluorescent layer achieves specific functions and decorative effects; the dyeing layer further enhances the decorative effect; and the sealing layer plays a final protective role. The layers work together to give the aluminum alloy workpieces not only good corrosion resistance and wear resistance, but also unique fluorescent and dyeing effects, meeting the needs of different application scenarios.

[0036] Compared with the prior art, this application has at least the following beneficial effects: 1) In the aluminum alloy surface treatment method with fluorescent layer of this application, aluminum alloy is used as the substrate. Through steps such as anodizing, local spraying of fluorescent ink, dyeing, and sealing, the aluminum alloy workpiece is formed from the surface of the substrate outward in sequence as a porous anodized layer, a local fluorescent layer, a dyed layer covering the whole area and a sealing layer. When there is no UV lamp irradiation, the aluminum alloy workpiece does not fluoresce. When UV lamp irradiation is applied, fluorescent patterns appear on the aluminum alloy workpiece, thereby playing the role of identification information and preventing counterfeiting. It meets the segmented needs of multiple fields such as industry, consumer goods, and security.

[0037] 2) The aluminum alloy workpieces prepared by the aluminum alloy surface treatment method with fluorescent layer of this application effectively prevent the intrusion of corrosive media, moisture, etc., thereby further improving the corrosion resistance and wear resistance of the aluminum alloy workpieces and improving the protective performance. Its adhesion reaches level 0 or 1, the RCA paper tape abrasion test reaches more than 320 cycles, and no defects are found after the neutral salt spray test. Detailed Implementation

[0038] The following detailed description of the contents of this application is provided through specific embodiments, comparative examples, and tables, but is not limited to all the arguments and data.

[0039] In the embodiments and comparative examples of this application, the fluorescent ink is composed of fluorescent orange, hydroxyl acrylic resin, BYK-110, BYK-306, BYK-066N, fumed silica, and ethyl acetate in a weight ratio of 30:43:1.2:2.8:0.3:0.5:40. Specifically, the fluorescent orange is fluorescent orange GG from Kunshan Haite Plastic Pigment Co., Ltd., the hydroxyl acrylic resin is hydroxyl acrylic resin YH2820 from Qingyuan Yake Chemical Co., Ltd., BYK-110, BYK-306, and BYK-066N are from BYK GmbH (Germany), the fumed silica is fumed silica HB-151 from Hubei Huifu Nanomaterials Co., Ltd., and the ethyl acetate is from Shandong Weijin Chemical Technology Co., Ltd. The dyeing solution used is an acidic lake blue A solution with a mass concentration of 6 g / L. The sealing solution used is a nickel acetate aqueous solution with a concentration of 9 g / L.

[0040] It is particularly important to emphasize that, unless otherwise specified, the raw materials, reagents or devices used in this application can be obtained from conventional commercial sources.

[0041] This application discloses a surface treatment method for aluminum alloys with a fluorescent layer, which specifically includes the following steps: S1. The anodizing tank is filled with a sulfuric acid solution with a mass concentration of 15%~20% as the oxidizing liquid. The temperature of the sulfuric acid solution is controlled at 19~23℃. The aluminum alloy substrate is placed in the anodizing tank, and a voltage of 12~16V is applied for anodizing for 50~60 minutes to form a porous anodized film on the surface of the aluminum alloy substrate.

[0042] Regarding step S1, in some specific implementations, the mass concentration of the sulfuric acid solution in the anodizing tank can be 15%, 16%, 18% or 20%, the temperature of the anodizing treatment can be 19°C, 20°C, 21°C, 22°C or 23°C, the voltage can be 12V, 14V, 15V or 16V, and the time can be 50min, 55min, 58min or 60min.

[0043] In some specific implementations, the aluminum alloy substrate undergoes a pre-anodizing treatment prior to the anodizing process. This pre-anodizing treatment includes degreasing, alkaline etching, neutralization, and chemical polishing.

[0044] The degreasing process uses an acidic degreasing solution with a mass concentration of 10%, which can be a phosphoric acid solution. The degreasing temperature can be 80℃, 85℃, 87℃ or 90℃, and the degreasing time can be 2min, 2.5min or 3min.

[0045] Alkaline etching uses an aqueous solution of sodium hydroxide, with a concentration of 50 g / L, 55 g / L, 60 g / L, 65 g / L, or 70 g / L. The etching temperature can be 50℃, 55℃, 60℃, 65℃, or 70℃, and the etching time can be 30s, 35s, 38s, or 40s.

[0046] Neutralization is carried out using a 15% sulfuric acid solution at room temperature, and the neutralization time can be 10s, 12s, or 15s.

[0047] Chemical polishing uses a mixed solution of 25% sulfuric acid and 75% phosphoric acid as the polishing solution. The temperature for chemical polishing can be 95℃, 100℃, 102℃ or 105℃, and the time for chemical polishing can be 40s, 45s or 50s.

[0048] S2. Using a printer with a nozzle diameter ≤0.1mm, set the spraying amount to 15~25g / m2, locally spray fluorescent ink onto the surface of the porous anodic oxide film, and cure it at 35~45℃ for 15~20min to form a local fluorescent layer. The area without fluorescent ink spraying is the non-fluorescent area.

[0049] Regarding step S2, in some specific implementations, the spraying amount can be 15g / m2, 18g / m2, 23g / m2 or 25g / m2, the curing temperature can be 35℃, 40℃, 43℃ or 45℃, and the curing time can be 15min, 16min, 18min or 20min.

[0050] In some specific implementations, a settling period is included before curing, which can be 10 minutes, 15 minutes, or 20 minutes. The purpose of settling is to allow the fluorescent ink to flow into the pores of the porous anodic oxide film surface, making the local fluorescent layer surface more uniform and also helping to improve the adhesion between the fluorescent layer and the porous anodic oxide film surface.

[0051] In some specific embodiments, the fluorescent ink includes fluorescent pigment, film-forming agent, dispersant, leveling agent, defoamer, filler, and solvent. The weight ratio of fluorescent pigment, film-forming agent, dispersant, leveling agent, defoamer, filler, and solvent is (25~35):(40~50):(1~3):(2~4.3):(0.2~0.5):(0.1~0.8):(35~40).

[0052] The fluorescent pigment is selected from at least one of fluorescent yellow, fluorescent orange, fluorescent red, and fluorescent green. The film-forming agent is selected from at least one of waterborne polyurethane resin, hydroxyl acrylic resin, and acrylic-polyurethane copolymer resin. The dispersant is selected from at least one of BYK-110, BYK-163, and TEGO Dispers 750W. The leveling agent is selected from at least one of BYK-306, TEGO Glide 410, and BYK-358N. The defoamer is selected from at least one of BYK-066N, Defom 6800, and Colloid 640. The filler is fumed silica or wollastonite powder. The solvent is ethyl acetate or butyl acetate.

[0053] S3. Immerse the aluminum alloy substrate with the local fluorescent layer in a dyeing tank containing dyeing solution for full-area dyeing. The dyeing time is 2-3 minutes. Remove the substrate and dry it in an oven at 90-105℃ for 10-20 minutes to form a dyed layer that covers the entire area.

[0054] Regarding step S3, in some specific implementations, the staining time can be 2 min, 2.5 min or 3 min, the drying temperature can be 90℃, 95℃, 98℃ or 105℃, and the drying temperature can be 10 min, 15 min, 18 min or 20 min.

[0055] S4. The aluminum alloy substrate covered with the above-mentioned dyeing layer is completely immersed in a sealing tank containing sealing liquid at 85~95℃ and sealed for 30~45 minutes to form a sealing layer that covers the entire area on the dyeing layer. The substrate is then removed, washed with water at 60~80℃ for 30 seconds, removed, and dried in an oven at 110~130℃ for 5~8 minutes to obtain the aluminum alloy workpiece.

[0056] Regarding step S4, in some specific embodiments, the temperature of the sealing liquid can be 85°C, 90°C, or 95°C, the sealing time can be 30 min, 35 min, 40 min, or 45 min, the water washing temperature can be 60°C, 65°C, 70°C, or 80°C, the drying temperature can be 110°C, 120°C, or 130°C, and the drying time can be 5 min, 6 min, or 8 min.

[0057] Based on the aluminum alloy surface treatment method with fluorescent layer of this application, the following examples and comparative examples are provided: Example 1

[0058] A surface treatment method for aluminum alloys with a fluorescent layer specifically includes the following steps: S1. The degreasing tank is filled with a 10% phosphoric acid solution, and the temperature of the degreasing tank is controlled at 80℃. The aluminum alloy substrate is placed in the degreasing tank for 2 minutes to remove oil. After rinsing with room temperature water for 5 seconds, it is placed in an alkaline etching tank containing a 50g / L sodium hydroxide aqueous solution and etched at 60℃ for 30 seconds. After rinsing with room temperature water for 5 seconds, it is placed in a neutralization tank containing a 15% sulfuric acid solution and neutralized at room temperature for 10 seconds. After rinsing with room temperature water for 5 seconds, it is placed in a mixed solution containing a 25% sulfuric acid solution and a 75% phosphoric acid solution and chemically polished at 95℃ for 45 seconds. After rinsing with room temperature water twice (5 seconds for the first rinse and 10 seconds for the second rinse), it is placed in a 20% sulfuric acid solution and anodized at 20℃ with a voltage of 16V for 50 minutes to form a porous anodized film on the surface of the aluminum alloy substrate.

[0059] S2. Using a printer with a nozzle diameter of 0.1mm, set the spraying amount to 18g / m2, and spray fluorescent ink locally onto the surface of the porous anodized film according to the pattern entered by the computer. Remove the film, let it stand for 10 minutes, and then cure it in a 40℃ oven for 15 minutes to form a local fluorescent layer. The areas without fluorescent ink spraying are non-fluorescent areas.

[0060] S3. Immerse the aluminum alloy substrate with the local fluorescent layer in a dyeing tank containing dyeing solution for 3 minutes to dye the entire area. Remove the substrate and dry it in a 90°C oven for 15 minutes to form a dyed layer that covers the entire area.

[0061] S4. The aluminum alloy substrate covered with the above-mentioned dyeing layer is completely immersed in a sealing tank containing sealing liquid at 85°C and sealed for 30 minutes to form a sealing layer that covers the entire area on the dyeing layer. The substrate is then removed, washed with water at 70°C for 30 seconds, removed again, and dried in an oven at 120°C for 5 minutes to obtain the aluminum alloy workpiece. Example 2

[0062] A method for surface treatment of aluminum alloy with a fluorescent layer is the same as in Example 1, except that the spraying amount in step S2 of Example 2 is 23 g / m2. Example 3

[0063] A surface treatment method for aluminum alloy with a fluorescent layer is the same as in Example 1, except that the curing temperature in step S2 of Example 3 is 35°C. Example 4

[0064] A surface treatment method for aluminum alloy with a fluorescent layer is the same as in Example 1, except that the curing temperature in step S2 of Example 4 is 45°C. Example 5

[0065] A surface treatment method for aluminum alloy with a fluorescent layer is the same as in Example 1, except that the curing time in step S2 of Example 5 is 18 min. Example 6

[0066] A surface treatment method for aluminum alloy with a fluorescent layer is the same as in Example 1, except that the curing time in step S2 of Example 6 is 20 min.

[0067] Comparative Example 1: A method for surface treatment of aluminum alloy with a fluorescent layer is the same as in Example 1, except that the amount of coating sprayed in step S2 of Comparative Example 1 is 13 g / m2.

[0068] Comparative Example 2: A surface treatment method for aluminum alloy with a fluorescent layer is the same as in Example 1, except that the curing temperature in step S2 of Comparative Example 2 is 30°C.

[0069] Comparative Example 3: A surface treatment method for aluminum alloy with a fluorescent layer is the same as in Example 1, except that the curing time in step S2 of Comparative Example 3 is 23 min.

[0070] Comparative Example 4: A surface treatment method for aluminum alloy with a fluorescent layer is the same as in Example 1, except that step S2 in Comparative Example 4 was not allowed to stand before curing.

[0071] Material performance testing: The aluminum alloy workpieces obtained in Examples 1-6 and Comparative Examples 1-4 were subjected to various performance tests, and the test methods are as follows: Appearance: Observe the product surface under a microscope. The product is considered qualified if there are no scratches, exposed bottom, whitening, yellowing, pitting, dirt, watermarks, or bubbling.

[0072] Total coating thickness and local fluorescent layer thickness were tested according to GB / T 8014.3-2005 "Methods for measuring the thickness of anodized films on aluminum and aluminum alloys (Part 3): Spectroscopy".

[0073] UV lamp irradiation: Irradiate the sample surface vertically with a UV lamp and observe whether there is fluorescence.

[0074] Adhesion (cross-cut test): Tested according to GB / T 9286 standard.

[0075] RCA paper tape abrasion resistance test: According to the ASTM F2357 test standard, under a fixed load of 175g pressure, the sample surface is repeatedly rubbed at a speed of 1r / s until the coating is worn through and the aluminum alloy substrate is exposed. The number of rubbing cycles at this time is recorded to quantify the abrasion resistance of the sample coating.

[0076] Corrosion resistance: Tested according to the neutral salt spray test in GB / T 12967.3-2022 "Test methods for anodic oxide films and organic polymer films of aluminum and aluminum alloys (Part 3): Salt spray test".

[0077] The test properties of the aluminum alloy workpieces in Examples 1-6 and Comparative Examples 1-4 are shown in Table 1 below:

[0078] The aluminum alloy surface treatment methods with fluorescent layers in Examples 1-6 use aluminum alloy as the substrate. Through steps such as anodizing, local spraying of fluorescent ink, dyeing, and sealing, the resulting aluminum alloy workpiece forms a porous anodized layer, a local fluorescent layer, a fully covered dyeing layer, and a sealing layer sequentially from the surface of the substrate outwards. The surface appearance of the resulting aluminum alloy workpiece is qualified, with no scratches, exposed substrate, whitening, yellowing, pitting, dirt, watermarks, or blistering. The total coating thickness is 10.5-15.9µm, the thickness of the local fluorescent layer is 2-4µm, a fluorescent pattern is visible when irradiated with a UV lamp, the adhesion reaches level 0 or 1, the RCA paper tape abrasion resistance test reaches more than 320 cycles, and no defects are found after the neutral salt spray test, meeting the segmented needs of multiple fields such as industry, consumer goods, and safety.

[0079] Compared with Example 1, the difference in Comparative Example 1 is that the spraying amount in step S2 of Comparative Example 1 is 13 g / m2. The results show that the total coating thickness and local fluorescent layer thickness of the aluminum alloy workpiece in Comparative Example 1 are reduced. The RCA paper tape abrasion test only lasts for 226 cycles. After the neutral salt spray test, the coating surface blistered. This may be because the spraying amount in step S2 is too small, which reduces the total thickness and local fluorescent layer thickness. At the same time, the thickness is too thin, which weakens the protective effect on the aluminum alloy substrate surface, resulting in reduced surface abrasion resistance and corrosion resistance.

[0080] Compared with Example 1, the difference in Comparative Example 2 is that the curing temperature in step S2 is 30°C. The results show that the coating adhesion of the aluminum alloy workpiece in Comparative Example 2 drops to level 2. After the neutral salt spray test, the coating surface cracks. This may be because the curing temperature in step S2 is too low, which makes the fluorescent layer incompletely cured, affecting the overall adhesion and corrosion resistance of the coating.

[0081] Compared with Example 1, the difference in Comparative Example 3 is that the curing time in step S2 of Comparative Example 3 is 23 min. The results show that the performance test results of the aluminum alloy workpiece of Comparative Example 3 are comparable to those of Example 1, indicating that the fluorescent ink has been cured relatively thoroughly within the curing time range of step S2 of this application.

[0082] Compared with Example 1, Comparative Example 4 differs in that step S2 in Comparative Example 4 was not allowed to stand before curing. The results showed that the aluminum alloy workpiece of Comparative Example 4 only had 226 cycles of RCA paper tape abrasion resistance test. After the neutral salt spray test, spots appeared on the coating surface. This may be because the coating was directly cured without standing before step S2 in Comparative Example 4, which caused some pores on the surface of the porous anodic oxide film to not be filled with fluorescent ink in time or not to be filled completely, thus resulting in defects on the coating surface and affecting the wear resistance and corrosion resistance of the coating.

[0083] Obviously, the above embodiments of this application are merely examples for clearly illustrating this application, and are not intended to limit the implementation of this application. For those skilled in the art, other variations or modifications can be made based on the above description. Any obvious variations or modifications derived from the technical solutions of this application are still within the protection scope of this application.

Claims

1. A method for surface treatment of aluminum alloy with a fluorescent layer, characterized in that, Includes the following steps: S1. The aluminum alloy substrate is anodized to form a porous anodized film on the surface of the aluminum alloy substrate. S2. Spray fluorescent ink onto the surface of the porous anodic oxide film locally, cure it to form a local fluorescent layer, and the area where fluorescent ink is not sprayed is a non-fluorescent area. S3. The porous anodic oxide film in the local fluorescent layer and the non-fluorescent area is stained and dried to form a stained layer that covers the entire area. S4. Perform sealing to form a sealing layer that covers the entire area on the dyed layer, and obtain the aluminum alloy workpiece.

2. The surface treatment method for aluminum alloys with a fluorescent layer according to claim 1, characterized in that, In step S1, the temperature of the anodizing treatment is 19~23℃, the voltage of the anodizing treatment is 12~16V, and the time of the anodizing treatment is 50~60min.

3. The surface treatment method for aluminum alloys with a fluorescent layer according to claim 1, characterized in that, In step S2, the spraying is performed using an inkjet printer with a nozzle diameter ≤0.1mm and a spraying amount of 15~25g / m2.

4. The surface treatment method for aluminum alloys with a fluorescent layer according to claim 1, characterized in that, In step S2, the curing temperature is 35~45℃ and the curing time is 15~20min.

5. The surface treatment method for aluminum alloys with a fluorescent layer according to claim 1, characterized in that, In step S2, before curing, a standing period of 10-20 minutes is included.

6. The surface treatment method for aluminum alloys with a fluorescent layer according to claim 1, characterized in that, In step S2, the fluorescent ink includes fluorescent pigments, film-forming agents, dispersants, leveling agents, defoamers, fillers, and solvents.

7. The surface treatment method for aluminum alloys with a fluorescent layer according to claim 6, characterized in that, In step S2, the weight ratio of the fluorescent pigment, film-forming agent, dispersant, leveling agent, defoamer, filler and solvent is (25~35):(40~50):(1~3):(2~4.3):(0.2~0.5):(0.1~0.8):(35~40).

8. The surface treatment method for aluminum alloys with a fluorescent layer according to claim 1, characterized in that, In step S3, the staining is immersion staining, and the immersion staining time is 2-3 minutes.

9. The surface treatment method for aluminum alloys with a fluorescent layer according to claim 1, characterized in that, In step S4, the sealing temperature is 85~95℃, and the sealing time is 30~45min.

10. An aluminum alloy workpiece, characterized in that, The workpiece is prepared by the method according to any one of claims 1 to 9, wherein the aluminum alloy workpiece is based on an aluminum alloy substrate, and a porous anodized layer, a local fluorescent layer, a fully covered dyeing layer and a sealing layer are formed sequentially from the surface of the substrate outwards, wherein the total thickness of the porous anodized layer, the local fluorescent layer, the dyeing layer and the sealing layer is 10.5 to 15.9 µm, and the thickness of the local fluorescent layer is 2 to 4 µm.

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