Ice-impact-resistant gradient foamed aluminum sandwich plate and preparation method thereof

Abstract

The invention relates to the technical field of ship and ocean engineering, in particular to an ice-impact-resistant gradient foamed aluminum sandwich plate and a preparation method thereof. The ice-impact-resistant gradient foamed aluminum sandwich plate is prepared from industrial pure aluminum powder, a modified titanium hydride foaming agent, a metal material for an upper panel, a metal material for a lower panel, an epoxy modified acrylate adhesive, a surface pretreatment material and an anti-corrosion material. The modified titanium hydride is coated with silicon dioxide, so that the pore structure of the foamed aluminum can be regulated and controlled, and the uniformity and stability of the core layer are improved; the epoxy modified acrylate adhesive has strong adhesion and toughness by utilizing the synergistic effect of epoxy resin and acrylate, so that the interface bonding between the panel and the foamed aluminum core layer is strengthened; the modified polyvinyl fluoride coating is modified by nano zinc oxide, so that the corrosion resistance and the adhesive force of the coating are enhanced; the three modified materials are cooperated with other materials, so that when the sandwich plate is resistant to ice impact, long-term service is guaranteed by means of plastic energy absorption of the gradient foamed aluminum core layer, load transmission of an adhesive interface and the anticorrosive layer.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding and marine engineering technology, specifically to an ice-impact resistant gradient foamed aluminum sandwich panel and its preparation method. Background Technology

[0002] Gradient aluminum foam sandwich panels are a new type of composite material that integrates structure and function. Its core is a layered structure of panel-core-panel, which is composed of a high-density pure aluminum / aluminum alloy panel and a gradient aluminum foam core layer with continuous / stepped changes in porosity, pore size or composition along the thickness direction, through processes such as welding and adhesive bonding. It achieves lightweight by virtue of the high porosity of the core layer, and also has high specific strength, high efficiency in energy absorption, optimized sound insulation and excellent electromagnetic shielding by relying on the synergistic effect of the panel and the gradient core layer.

[0003] In existing technologies, firstly, the performance of the foaming agent is poor, and the uniformity of the foam aluminum pores and the controllability of the gradient structure are poor, resulting in low energy absorption efficiency and insufficient structural stability during ice impact resistance; secondly, the pretreatment of the bonding surface between the panel and the foam aluminum core layer is insufficient, and the performance of the adhesive is inadequate, resulting in weak bonding force between the two and easy delamination under ice impact; thirdly, the anti-corrosion measures are lacking. In humid and corrosive environments containing ice, metals are easily corroded, which shortens the service life of the sandwich panel and weakens its structural performance against ice impact.

[0004] Based on this, the present invention provides a gradient foamed aluminum sandwich panel resistant to ice impact and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a gradient aluminum foam sandwich panel resistant to ice impact and its preparation method. The gradient aluminum foam sandwich panel prepared by this invention not only has a lower peak ice impact force, but also has a higher impact energy absorption density and interfacial shear strength.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a gradient foamed aluminum sandwich panel resistant to ice impact and its preparation method, comprising the following raw materials in parts by weight: 20-30 parts of industrial pure aluminum powder, 3-5 parts of modified titanium hydride foaming agent, 60-80 parts of metal material for the upper panel, 80-100 parts of metal material for the lower panel, 3-6 parts of epoxy modified acrylate adhesive, 30-42 parts of surface pretreatment material, and 12-20 parts of anti-corrosion material; The metal materials used for the upper and lower panels are Q690 high-strength steel, 6061 aluminum alloy or TC4 titanium alloy. The surface pretreatment material consists of 10-15 parts acetone solution, 5-7 parts white corundum sand, and 15-20 parts dilute sulfuric acid solution with a mass fraction of 5-8%. The anti-corrosion material consists of 8-12 parts of potassium dichromate solution with a mass fraction of 3-5% and 4-8 parts of modified polyvinyl fluoride coating material.

[0007] Preferably, the preparation steps of the modified titanium hydride are as follows: KH-550 ethanol solution is added to titanium hydride particles, and the mixture is stirred at 200 r / min for 1-2 h at 30-40°C to graft KH-550 onto the particle surface. The particles are then rinsed with deionized water and dried at 80°C. The surface-functionalized titanium hydride is added to deionized water at a mass ratio of 1:40, heated to 80-90°C, and stirred at 300 r / min to form a uniform suspension. Simultaneously, a sodium silicate solution containing 2% polyvinyl alcohol (by mass) and a hydrochloric acid solution containing boron are prepared. A buffer acid solution containing polyvinyl alcohol was prepared by mixing sand and sodium hydroxide buffer solution. The above-mentioned sodium silicate solution containing polyvinyl alcohol and buffer acid solution were simultaneously added dropwise using two burettes at a rate of 40 mL / h. During the titration, the mixture was continuously stirred at 300 r / min to allow silica to nucleate uniformly on the surface of titanium hydride. After the titration was completed, stirring was continued for 20-30 min. The mixture was then allowed to cool naturally to room temperature and aged for 2-3 h. After filtration, the mixture was washed 3-5 times with deionized water until neutral. Finally, it was dried at 80-100℃ for 2-4 h to obtain silica-coated modified titanium hydride.

[0008] Preferably, in the KH-550 ethanol solution, the volume ratio of ethanol to deionized water is 9:1; in the 1 mol / L sodium silicate solution containing 2% polyvinyl alcohol, the volume ratio of sodium silicate solution to polyvinyl alcohol solution is 9:1; the pH of the borax-sodium hydroxide buffer solution is 9.5, and the hydrochloric acid solution and the borax-sodium hydroxide buffer solution are mixed at a volume ratio of 1:1.

[0009] Preferably, the raw material of the foamed aluminum core layer is divided into three layers according to a gradient structure, with the total mass ratio of the high-density layer near the top panel: the middle low-density layer: the high-density layer near the bottom panel being (25-35): (40-60): (15-25); wherein, the high-density layer near the top panel consists of 92-95 parts of industrial pure aluminum powder and 5-8 parts of modified titanium hydride foaming agent, the middle low-density layer consists of 85-90 parts of industrial pure aluminum powder and 10-15 parts of modified titanium hydride foaming agent, and the high-density layer near the bottom panel consists of 90-93 parts of industrial pure aluminum powder and 7-10 parts of modified titanium hydride foaming agent.

[0010] Preferably, the raw material composition of the epoxy-modified acrylate is: 40-50 parts epoxy resin, 10-15 parts hydroxyethyl methacrylate, 20-25 parts butyl acrylate, 1-3 parts benzoyl peroxide initiator, 0.1-0.5 parts hydroquinone polymerization inhibitor, 1-3 parts KH-550, and 0.5-1.5 parts triethylamine catalyst.

[0011] Preferably, the preparation steps of the epoxy-modified acrylate are as follows: epoxy resin is added to a four-necked flask, heated to 80–100°C to melt it, and stirred at a speed of 200–300 r / min; a mixture of hydroxyethyl methacrylate and butyl acrylate monomers is added dropwise at a dropping rate of 10–15 mL / h, while triethylamine catalyst is added simultaneously, and the reaction is maintained at the temperature for 2–4 h to allow the epoxy groups to undergo a ring-opening grafting reaction with the hydroxyl / carboxyl groups of the acrylate to obtain an epoxy acrylate prepolymer; the prepolymer is cooled to 60–70°C, hydroquinone and KH-550 are added sequentially and stirred for 30 min, followed by the addition of benzoyl peroxide, and stirring is continued for 1 h until the mixture is homogeneous. The mixture is then cooled to room temperature to obtain the epoxy-modified acrylate adhesive.

[0012] Preferably, the raw material composition of the modified polyvinyl fluoride coating material is: 80-90 parts polyvinyl fluoride resin powder, 5-10 parts nano zinc oxide, 150-200 parts N,N-dimethylacetamide, and 1-2 parts polyether-modified polysiloxane leveling agent.

[0013] Preferably, the preparation method of the modified polyvinyl fluoride coating material is as follows: polyvinyl fluoride resin is added to N,N-dimethylacetamide, placed in a sealed constant temperature stirring device, heated to 120-130℃, and stirred at 300r / min for 50-80min to fully dissolve the resin and form a uniform and transparent polyvinyl fluoride resin solution; nano zinc oxide is added to the above resin solution, and an ultrasonic device with a power of 300-500W is turned on to disperse for 30-60min to ensure that the nano zinc oxide particles are not agglomerated and are uniformly distributed in the resin solution; polyether modified polysiloxane leveling agent is added to the dispersed solution, and stirring is continued for 30min, followed by filtration through a 200-mesh filter to obtain a modified polyvinyl fluoride coating material with a solid content of 40-50%.

[0014] Preferably, the nano-zinc oxide undergoes modification treatment, specifically through the following steps: Anhydrous ethanol and deionized water are weighed at a mass ratio of 9:1 and poured into a three-necked flask. Hydrochloric acid is added dropwise while stirring to adjust the pH to 4-5. Then, 1-5 parts of KH-550 are slowly added, and the mixture is stirred at 25-30℃ for 30-60 minutes to ensure complete hydrolysis of KH-550. 100 parts of nano-zinc oxide are added to the hydrolysate, and the temperature is raised to 50-60℃. The mixture is stirred at 200-300 r / min for 2-3 hours. The silanol groups generated from the hydrolysis of KH-550 undergo a condensation reaction with the hydroxyl groups on the surface of the nano-zinc oxide, causing KH-550 to be grafted onto the surface of the nano-zinc oxide. After the reaction, the mixture is centrifuged to collect the solid particles. The particles are washed 3-5 times with anhydrous ethanol and finally dried in a vacuum drying oven at 60-80℃ for 4-6 hours to complete the modification of the nano-zinc oxide.

[0015] A method for preparing an ice-impact resistant gradient aluminum foam sandwich panel includes the following steps: S1. Preparation of gradient aluminum foam core preform: After the three layers of ingredients are mixed evenly, they are laid in layers in a steel mold. After each layer is laid, it is pre-pressed with a pressure of 5-8 MPa for 10-15 min. The mold is then sent into a sintering furnace, argon gas is introduced, and the temperature is raised to 700-750℃ at a rate of 5-8℃ / min. The temperature is held for 2-4 h for foaming and sintering. Then, it is cooled to below 200℃ at a rate of 3-5℃ / min and removed to obtain the gradient aluminum foam blank. S2. Surface pretreatment: Use an acetone solution at 20-25℃ to ultrasonically clean the mating surfaces of the upper and lower panels for 15-20 minutes to remove surface oil stains. Then, use 80-120 mesh white corundum sand to sandblast the mating surfaces to achieve a surface roughness of 3.2-6.2μm. Finally, immerse the upper and lower panels in a 5-8% (w / w) dilute sulfuric acid solution for 5-8 minutes, wash with water until the pH reaches 6-7, and dry at 80-100℃. Use the same steps to pretreat the upper and lower mating surfaces of the gradient foam aluminum blank. S3. Composite connection: The pretreated upper panel, gradient aluminum foam blank and lower panel are stacked in sequence in a hot press. Epoxy modified acrylic adhesive is applied to the bonding surface. A pressure of 0.1-0.3MPa is applied, argon gas is introduced and the temperature is raised to 50-60℃. The temperature is maintained for 90-120 minutes to complete the curing. S4. Anti-corrosion treatment: After the composite structure is cooled to room temperature in the furnace, the shape is trimmed by milling. The trimmed structure is then immersed in potassium dichromate solution at 25-35℃ for 10-15 minutes to form a passivation film. After being taken out and dried, a modified polyvinyl fluoride coating material is sprayed on and cured at 100-120℃ for 40-60 minutes to finally obtain an ice-impact resistant gradient aluminum foam sandwich panel.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention employs a modified titanium hydride foaming agent, precisely controlling the hydrogen release behavior of titanium hydride through a silica coating layer, thereby forming a high-density-low-density-high-density gradient pore structure in the aluminum foam core layer. This gradient structure works synergistically with the Q690 high-strength steel, 6061 aluminum alloy, or TC4 titanium alloy panel, enabling the low-density layer to efficiently absorb energy and the high-density layer to provide stable support during ice impact, significantly improving the sandwich panel's impact load resistance and energy absorption efficiency. At the same time, it provides a uniform and suitable core layer surface for the bonding of epoxy-modified acrylate adhesive.

[0017] 2. This invention uses an epoxy-modified acrylate adhesive. The synergistic modification of epoxy resin and acrylate gives the adhesive both high strength and high toughness. With the help of KH-550 coupling agent, triethylamine catalyst and other components, it works synergistically with the surfaces of the metal panel and the aluminum foam core layer, which have been cleaned with acetone, roughened by sandblasting and activated with dilute sulfuric acid, to greatly enhance the interfacial bonding strength. This ensures that the load is effectively transferred between the panel and the core layer during ice impact, avoids interface debonding, and the toughness of the adhesive can buffer impact stress, which complements the energy absorption characteristics of the gradient aluminum foam.

[0018] 3. This invention employs a modified polyvinyl fluoride coating material. The nano-zinc oxide modified with KH-550 works synergistically with polyvinyl fluoride resin to improve the coating's density and corrosion resistance, while also enhancing its adhesion to the potassium dichromate passivation film. The potassium dichromate inorganic passivation film and the modified polyvinyl fluoride organic coating work together to construct an inorganic-organic gradient anti-corrosion barrier, effectively resisting corrosion in complex environments. At the same time, the coating's impact toughness, along with the performance of the gradient aluminum foam core layer and the epoxy-modified acrylate adhesive, synergistically ensure the stability of the sandwich panel's anti-ice impact performance during long-term service. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application are described clearly and completely.

[0021] Example 1: A gradient foamed aluminum sandwich panel resistant to ice impact, comprising the following raw materials in parts by weight: 20 parts of industrial pure aluminum powder, 3 parts of modified titanium hydrogenation foaming agent, 60 parts of metal material for the upper panel, 80 parts of metal material for the lower panel, 3 parts of epoxy modified acrylate adhesive, 30 parts of surface pretreatment material, and 12 parts of anti-corrosion material. The metal materials used for the top and bottom panels are Q690 high-strength steel, 6061 aluminum alloy, or TC4 titanium alloy. The surface pretreatment material consists of 10 parts acetone solution, 5 parts white corundum sand, and 15 parts dilute sulfuric acid solution with a mass fraction of 5%. The anti-corrosion material consists of 8 parts of potassium dichromate solution with a mass fraction of 3% and 4 parts of modified polyvinyl fluoride coating material.

[0022] The preparation steps of modified titanium hydride are as follows: Titanium hydride particles are soaked in a 5% (w / w) acetic acid solution for 1 hour to remove the oxide layer, and then rinsed with deionized water until the pH of the rinsing solution reaches 6; KH-550 ethanol solution is added to the treated titanium hydride particles, and the mixture is stirred at 200 r / min at 30℃ for 1 hour to graft KH-550 onto the particle surface, followed by rinsing with deionized water and drying at 80℃; the surface-functionalized titanium hydride is added to deionized water at a mass ratio of 1:40, heated to 80℃, and stirred at 300 r / min to form a uniform suspension; simultaneously... Prepare a sodium silicate solution containing 2% polyvinyl alcohol by mass, and a buffer acid solution consisting of hydrochloric acid solution and borax-sodium hydroxide buffer solution. Simultaneously add the above-mentioned sodium silicate solution containing polyvinyl alcohol and buffer acid solution dropwise using two burettes at a rate of 40 mL / h. During the titration, continuously stir at 300 r / min to allow silica to uniformly nucleate on the surface of titanium hydride. After titration, continue stirring for 20 min, allow to cool naturally to room temperature and age for 2 h. After filtration, wash three times with deionized water until neutral, and finally dry at 80℃ for 2 h to obtain silica-coated modified titanium hydride.

[0023] In the KH-550 ethanol solution, the volume ratio of ethanol to deionized water is 9:1; in the 1 mol / L sodium silicate solution containing 2% polyvinyl alcohol, the volume ratio of sodium silicate solution to polyvinyl alcohol solution is 9:1; the pH of the borax-sodium hydroxide buffer solution is 9.5, and the hydrochloric acid solution is mixed with the borax-sodium hydroxide buffer solution at a volume ratio of 1:1.

[0024] The raw materials for the aluminum foam core layer are divided into three layers according to a gradient structure: a high-density layer near the top panel, a low-density layer in the middle, and a high-density layer near the bottom panel, with a total mass ratio of 25:40:15. Among them, the high-density layer near the top panel consists of 92 parts of industrial pure aluminum powder and 5 parts of modified titanium hydride foaming agent; the low-density layer in the middle consists of 85 parts of industrial pure aluminum powder and 10 parts of modified titanium hydride foaming agent; and the high-density layer near the bottom panel consists of 90 parts of industrial pure aluminum powder and 7 parts of modified titanium hydride foaming agent.

[0025] The raw material composition of epoxy-modified acrylate is as follows: 40 parts epoxy resin, 10 parts hydroxyethyl methacrylate, 20 parts butyl acrylate, 1 part benzoyl peroxide initiator, 0.1 part hydroquinone polymerization inhibitor, 1 part KH-550, and 0.5 parts triethylamine catalyst.

[0026] The preparation steps of epoxy-modified acrylate are as follows: epoxy resin is added to a four-necked flask and heated to 80°C to melt it. The mixture is stirred at 200 r / min. A mixture of hydroxyethyl methacrylate and butyl acrylate monomers is added dropwise at a rate of 10 mL / h, while triethylamine catalyst is added. The mixture is kept at this temperature for 2 h to allow the epoxy groups to undergo a ring-opening grafting reaction with the hydroxyl / carboxyl groups of the acrylate, thus obtaining an epoxy acrylate prepolymer. The prepolymer is cooled to 60°C, and hydroquinone and KH-550 are added sequentially and stirred for 30 min. Benzoyl peroxide is then added, and the mixture is stirred for another 1 h until homogeneous. The mixture is then cooled to room temperature to obtain the epoxy-modified acrylate adhesive.

[0027] The raw material composition of the modified polyvinyl fluoride coating material is: 80 parts polyvinyl fluoride resin powder, 5 parts nano zinc oxide, 150 parts N,N-dimethylacetamide, and 1 part polyether modified polysiloxane leveling agent.

[0028] The preparation method of the modified polyvinyl fluoride coating material is as follows: polyvinyl fluoride resin is added to N,N-dimethylacetamide, placed in a sealed constant temperature stirring device, heated to 120℃, and stirred at 300r / min for 50min to form a uniform and transparent polyvinyl fluoride resin solution; nano zinc oxide is added to the above resin solution, and an ultrasonic device with a power of 300W is turned on to disperse for 30min to ensure that the nano zinc oxide particles are not agglomerated and are uniformly distributed in the resin solution; polyether modified polysiloxane leveling agent is added to the dispersed solution, and stirring is continued for 30min, followed by filtration through a 200-mesh filter to obtain a modified polyvinyl fluoride coating material with a solid content of 40%.

[0029] The modification of nano-zinc oxide involved the following steps: Anhydrous ethanol and deionized water were measured at a mass ratio of 9:1 and poured into a three-necked flask. Hydrochloric acid was added dropwise while stirring to adjust the pH to 4. Then, 1 part of KH-550 was slowly added, and the mixture was stirred at 25°C for 30 minutes to allow for complete hydrolysis of KH-550. 100 parts of nano-zinc oxide were added to the hydrolysate, and the mixture was heated to 50°C and stirred at 200 r / min for 2 hours. The silanol groups generated from the hydrolysis of KH-550 underwent a condensation reaction with the hydroxyl groups on the surface of the nano-zinc oxide, resulting in the grafting of KH-550 onto the surface of the nano-zinc oxide. After the reaction, the mixture was centrifuged to collect the solid particles. The particles were washed three times with anhydrous ethanol and finally dried in a vacuum drying oven at 60°C for 4 hours to complete the modification of the nano-zinc oxide.

[0030] A method for preparing an ice-impact resistant gradient aluminum foam sandwich panel includes the following steps: S1. Preparation of gradient aluminum foam core preform: After the three layers of ingredients are mixed evenly, they are laid in layers in a steel mold. After each layer is laid, it is pre-pressed with a pressure of 5MPa for 10 minutes. The mold is then sent into a sintering furnace, argon gas is introduced, and the temperature is raised to 700℃ at a rate of 5℃ / min. It is held at this temperature for 2 hours for foaming and sintering. Then it is cooled to below 200℃ at a rate of 3℃ / min and removed to obtain the gradient aluminum foam blank. S2. Surface pretreatment: The mating surfaces of the upper and lower panels are ultrasonically cleaned with acetone solution at 20℃ for 15 minutes to remove surface oil stains. Then, the mating surfaces are sandblasted with 80-mesh white corundum sand to achieve a surface roughness of 3.2μm. Finally, the upper and lower panels are immersed in a 5% (w / w) dilute sulfuric acid solution for 5 minutes, washed with water until the pH reaches 6, and dried at 80℃. The same steps are used to pretreat the upper and lower mating surfaces of the gradient foam aluminum blank. S3. Composite connection: The pretreated upper panel, gradient aluminum foam blank and lower panel are stacked in sequence in a hot press. Epoxy modified acrylic adhesive is applied to the bonding surface. A pressure of 0.1MPa is applied, argon gas is introduced and the temperature is raised to 50℃. The temperature is maintained for 90 minutes to complete the curing. S4. Anti-corrosion treatment: After the composite structure is cooled to room temperature in the furnace, the shape is trimmed by milling. The trimmed structure is then immersed in potassium dichromate solution at 25°C for 10 minutes to form a passivation film. After being taken out and dried, a modified polyvinyl fluoride coating material is sprayed on and cured at 100°C for 40 minutes to finally obtain an ice-impact resistant gradient aluminum foam sandwich panel.

[0031] Example 2: A gradient foamed aluminum sandwich panel resistant to ice impact, comprising the following raw materials in parts by weight: 25 parts of industrial pure aluminum powder, 4 parts of modified titanium hydrogenation foaming agent, 70 parts of metal material for the upper panel, 90 parts of metal material for the lower panel, 4.5 parts of epoxy modified acrylate adhesive, 36 parts of surface pretreatment material, and 16 parts of anti-corrosion material. The metal materials used for the top and bottom panels are Q690 high-strength steel, 6061 aluminum alloy, or TC4 titanium alloy. The surface pretreatment material consists of 12.5 parts acetone solution, 6 parts white corundum sand, and 17.5 parts dilute sulfuric acid solution with a mass fraction of 6.5%. The anti-corrosion material consists of 10 parts of potassium dichromate solution with a mass fraction of 4% and 6 parts of modified polyvinyl fluoride coating material.

[0032] The preparation steps of modified titanium hydride are as follows: Titanium hydride particles are soaked in a 6.5% acetic acid solution for 1.5 hours to remove the oxide layer, and then rinsed with deionized water until the pH of the rinsing solution reaches 6.5; KH-550 ethanol solution is added to the treated titanium hydride particles, and the mixture is stirred at 200 r / min at 35°C for 1.5 hours to graft KH-550 onto the particle surface; the particles are then rinsed with deionized water and dried at 80°C; the surface-functionalized titanium hydride is added to deionized water at a mass ratio of 1:40, heated to 85°C, and stirred at 300 r / min to form a uniform suspension. Simultaneously prepare a sodium silicate solution containing 2% polyvinyl alcohol by mass, and a buffer acid solution consisting of hydrochloric acid solution and borax-sodium hydroxide buffer solution. Add the above-mentioned sodium silicate solution containing polyvinyl alcohol and buffer acid solution simultaneously using two burettes at a rate of 40 mL / h. During the titration, continuously stir at 300 r / min to ensure uniform nucleation of silica on the surface of titanium hydride. After titration, continue stirring for 25 min, allow to cool naturally to room temperature, and age for 2.5 h. After filtration, wash four times with deionized water until neutral, and finally dry at 90℃ for 3 h to obtain silica-coated modified titanium hydride.

[0033] In the KH-550 ethanol solution, the volume ratio of ethanol to deionized water is 9:1; in the 1 mol / L sodium silicate solution containing 2% polyvinyl alcohol, the volume ratio of sodium silicate solution to polyvinyl alcohol solution is 9:1; the pH of the borax-sodium hydroxide buffer solution is 9.5, and the hydrochloric acid solution is mixed with the borax-sodium hydroxide buffer solution at a volume ratio of 1:1.

[0034] The raw materials for the aluminum foam core layer are divided into three layers according to a gradient structure: a high-density layer near the top panel, a low-density layer in the middle, and a high-density layer near the bottom panel, with a total mass ratio of 30:50:20. Specifically, the high-density layer near the top panel consists of 93.5 parts of industrial pure aluminum powder and 6.5 parts of modified titanium hydride foaming agent; the low-density layer in the middle consists of 87.5 parts of industrial pure aluminum powder and 12.5 parts of modified titanium hydride foaming agent; and the high-density layer near the bottom panel consists of 91.5 parts of industrial pure aluminum powder and 8.5 parts of modified titanium hydride foaming agent.

[0035] The raw material composition of epoxy-modified acrylate is as follows: 45 parts epoxy resin, 12.5 parts hydroxyethyl methacrylate, 22.5 parts butyl acrylate, 2 parts benzoyl peroxide initiator, 0.3 parts hydroquinone polymerization inhibitor, 2 parts KH-550, and 1 part triethylamine catalyst.

[0036] The preparation steps of epoxy-modified acrylate are as follows: epoxy resin is added to a four-necked flask and heated to 90°C to melt it. The mixture is stirred at 250 r / min. A mixture of hydroxyethyl methacrylate and butyl acrylate monomers is added dropwise at a rate of 12.5 mL / h, while triethylamine catalyst is added. The mixture is kept at this temperature for 3 h to allow the epoxy groups to undergo a ring-opening grafting reaction with the hydroxyl / carboxyl groups of the acrylate, thus obtaining an epoxy acrylate prepolymer. The prepolymer is cooled to 65°C, and hydroquinone and KH-550 are added sequentially and stirred for 30 min. Benzoyl peroxide is then added, and the mixture is stirred for another 1 h until homogeneous. The mixture is then cooled to room temperature to obtain the epoxy-modified acrylate adhesive.

[0037] The raw material composition of the modified polyvinyl fluoride coating material is: 85 parts polyvinyl fluoride resin powder, 7.5 parts nano zinc oxide, 175 parts N,N-dimethylacetamide, and 1.5 parts polyether modified polysiloxane leveling agent.

[0038] The preparation method of the modified polyvinyl fluoride coating material is as follows: Polyvinyl fluoride resin is added to N,N-dimethylacetamide, placed in a sealed constant temperature stirring device, heated to 125℃, and stirred at 300r / min for 65min to fully dissolve the resin and form a uniform and transparent polyvinyl fluoride resin solution; nano zinc oxide is added to the above resin solution, and an ultrasonic device with a power of 400W is turned on to disperse for 45min to ensure that the nano zinc oxide particles are not agglomerated and are uniformly distributed in the resin solution; polyether modified polysiloxane leveling agent is added to the dispersed solution, and stirring is continued for 30min, followed by filtration through a 200-mesh filter to obtain a modified polyvinyl fluoride coating material with a solid content of 45%.

[0039] The modification of nano-zinc oxide involved the following steps: Anhydrous ethanol and deionized water were measured at a mass ratio of 9:1 and poured into a three-necked flask. Hydrochloric acid was added dropwise while stirring to adjust the pH to 4.5. Then, 3 parts of KH-550 were slowly added, and the mixture was stirred at 27°C for 45 minutes to allow for complete hydrolysis of KH-550. 100 parts of nano-zinc oxide were added to the hydrolysate, and the temperature was raised to 55°C. The mixture was stirred at 250 r / min for 2.5 hours. The silanol groups generated from the hydrolysis of KH-550 underwent a condensation reaction with the hydroxyl groups on the surface of the nano-zinc oxide, resulting in the grafting of KH-550 onto the surface of the nano-zinc oxide. After the reaction, the mixture was centrifuged to collect the solid particles. The particles were washed four times with anhydrous ethanol and finally dried in a vacuum drying oven at 70°C for 5 hours to complete the modification of the nano-zinc oxide.

[0040] A method for preparing an ice-impact resistant gradient aluminum foam sandwich panel includes the following steps: S1. Preparation of gradient aluminum foam core preform: After the three layers of ingredients are mixed evenly, they are laid in layers in a steel mold. After each layer is laid, it is pre-pressed with a pressure of 6MPa for 12min. The mold is then sent into a sintering furnace, argon gas is introduced, and the temperature is raised to 725℃ at a rate of 6℃ / min. It is held at this temperature for 3h for foaming and sintering. Then it is cooled to below 200℃ at a rate of 4℃ / min and removed to obtain the gradient aluminum foam blank. S2. Surface pretreatment: The mating surfaces of the upper and lower panels are ultrasonically cleaned with acetone solution at 22°C for 17 minutes to remove surface oil stains. Then, the mating surfaces are sandblasted with 100-mesh white corundum abrasive to achieve a surface roughness of 4.7μm. Finally, the upper and lower panels are immersed in a 6.5% (w / w) dilute sulfuric acid solution for 6 minutes, washed with water until the pH reaches 6.5, and dried at 90°C. The same steps are used to pretreat the upper and lower mating surfaces of the gradient foam aluminum blank. S3. Composite connection: The pretreated upper panel, gradient aluminum foam blank and lower panel are stacked in sequence in a hot press. Epoxy modified acrylate adhesive is applied to the bonding surface, a pressure of 0.2MPa is applied, argon gas is introduced and the temperature is raised to 55℃, and the temperature is maintained for 105min to complete the curing. S4. Anti-corrosion treatment: After the composite structure is cooled to room temperature in the furnace, the shape is trimmed by milling. The trimmed structure is then immersed in potassium dichromate solution at 30°C for 12 minutes to form a passivation film. After being taken out and dried, a modified polyvinyl fluoride coating material is sprayed on and cured at 110°C for 50 minutes to finally obtain an ice-impact resistant gradient aluminum foam sandwich panel.

[0041] Example 3: A gradient foamed aluminum sandwich panel resistant to ice impact, comprising the following raw materials in parts by weight: 30 parts of industrial pure aluminum powder, 5 parts of modified titanium hydrogenation foaming agent, 80 parts of metal material for the upper panel, 100 parts of metal material for the lower panel, 6 parts of epoxy modified acrylate adhesive, 42 parts of surface pretreatment material, and 20 parts of anti-corrosion material. The metal materials used for the top and bottom panels are Q690 high-strength steel, 6061 aluminum alloy, or TC4 titanium alloy. The surface pretreatment material consists of 15 parts acetone solution, 7 parts white corundum sand, and 20 parts dilute sulfuric acid solution with a mass fraction of 8%. The anti-corrosion material consists of 12 parts of potassium dichromate solution with a mass fraction of 5% and 8 parts of modified polyvinyl fluoride coating material.

[0042] The preparation steps of modified titanium hydride are as follows: Titanium hydride particles are soaked in an 8% (w / w) acetic acid solution for 2 hours to remove the oxide layer, and then rinsed with deionized water until the pH of the rinsing solution reaches 7; KH-550 ethanol solution is added to the treated titanium hydride particles, and the mixture is stirred at 200 r / min at 40℃ for 2 hours to graft KH-550 onto the particle surface, followed by rinsing with deionized water and drying at 80℃; the surface-functionalized titanium hydride is added to deionized water at a mass ratio of 1:40, heated to 90℃, and stirred at 300 r / min to form a uniform suspension; simultaneously... Prepare a sodium silicate solution containing 2% polyvinyl alcohol by mass, and a buffer acid solution consisting of hydrochloric acid solution and borax-sodium hydroxide buffer solution. Add the above-mentioned sodium silicate solution containing polyvinyl alcohol and buffer acid solution simultaneously dropwise using two burettes at a rate of 40 mL / h. During the titration, continuously stir at 300 r / min to allow silica to uniformly nucleate on the surface of titanium hydride. After titration, continue stirring for 30 min, allow to cool naturally to room temperature and age for 3 h. After filtration, wash five times with deionized water until neutral, and finally dry at 100℃ for 4 h to obtain silica-coated modified titanium hydride.

[0043] In the KH-550 ethanol solution, the volume ratio of ethanol to deionized water is 9:1; in the 1 mol / L sodium silicate solution containing 2% polyvinyl alcohol, the volume ratio of sodium silicate solution to polyvinyl alcohol solution is 9:1; the pH of the borax-sodium hydroxide buffer solution is 9.5, and the hydrochloric acid solution is mixed with the borax-sodium hydroxide buffer solution at a volume ratio of 1:1.

[0044] The raw materials for the aluminum foam core layer are divided into three layers according to a gradient structure: a high-density layer near the top panel, a low-density layer in the middle, and a high-density layer near the bottom panel, with a total mass ratio of 35:60:25. Among them, the high-density layer near the top panel consists of 95 parts of industrial pure aluminum powder and 8 parts of modified titanium hydride foaming agent; the low-density layer in the middle consists of 90 parts of industrial pure aluminum powder and 15 parts of modified titanium hydride foaming agent; and the high-density layer near the bottom panel consists of 93 parts of industrial pure aluminum powder and 10 parts of modified titanium hydride foaming agent.

[0045] The raw material composition of epoxy-modified acrylate is as follows: 50 parts epoxy resin, 15 parts hydroxyethyl methacrylate, 25 parts butyl acrylate, 3 parts benzoyl peroxide initiator, 4 parts diethylenetriamine synergistic curing agent, 0.5 parts hydroquinone polymerization inhibitor, 3 parts KH-550, and 1.5 parts triethylamine catalyst.

[0046] The preparation steps of epoxy-modified acrylate are as follows: epoxy resin is added to a four-necked flask and heated to 100℃ to melt it. The mixture is stirred at 300 r / min. A mixture of hydroxyethyl methacrylate and butyl acrylate monomers is added dropwise at a rate of 15 mL / h, while triethylamine catalyst is added. The mixture is kept at this temperature for 4 h to allow the epoxy groups to undergo a ring-opening grafting reaction with the hydroxyl / carboxyl groups of the acrylate, thus obtaining an epoxy acrylate prepolymer. The prepolymer is cooled to 70℃, and hydroquinone and KH-550 are added sequentially and stirred for 30 min. Then, benzoyl peroxide and diethylenetriamine are added in batches, and the mixture is stirred for another 1 h until it is homogeneous. The mixture is then cooled to room temperature to obtain the epoxy-modified acrylate adhesive.

[0047] The raw material composition of the modified polyvinyl fluoride coating material is: 90 parts polyvinyl fluoride resin powder, 10 parts nano zinc oxide, 200 parts N,N-dimethylacetamide, and 2 parts polyether modified polysiloxane leveling agent.

[0048] The preparation method of the modified polyvinyl fluoride coating material is as follows: Polyvinyl fluoride resin is added to N,N-dimethylacetamide, placed in a sealed constant temperature stirring device, heated to 130℃, and stirred at 300r / min for 80min to fully dissolve the resin and form a uniform and transparent polyvinyl fluoride resin solution; nano zinc oxide is added to the above resin solution, and an ultrasonic device with a power of 500W is turned on to disperse for 60min to ensure that the nano zinc oxide particles are not agglomerated and are uniformly distributed in the resin solution; polyether modified polysiloxane leveling agent is added to the dispersed solution, and stirring is continued for 30min, followed by filtration through a 200-mesh filter to obtain a modified polyvinyl fluoride coating material with a solid content of 50%.

[0049] The modification of nano-zinc oxide involved the following steps: Anhydrous ethanol and deionized water were measured at a mass ratio of 9:1 and poured into a three-necked flask. Hydrochloric acid was added dropwise under stirring to adjust the pH to 5. Then, 5 parts of KH-550 were slowly added, and the mixture was stirred at 30°C for 60 minutes to allow for complete hydrolysis of KH-550. 100 parts of nano-zinc oxide were added to the hydrolysate, and the temperature was raised to 60°C. The mixture was stirred at 300 r / min for 3 hours. The silanol groups generated from the hydrolysis of KH-550 underwent a condensation reaction with the hydroxyl groups on the surface of nano-ZnO, allowing KH-550 to be grafted onto the surface of the nano-zinc oxide. After the reaction, the mixture was centrifuged to collect the solid particles. The particles were washed five times with anhydrous ethanol and finally dried in an 80°C vacuum drying oven for 6 hours to complete the modification of the nano-zinc oxide.

[0050] A method for preparing an ice-impact resistant gradient aluminum foam sandwich panel includes the following steps: S1. Preparation of gradient aluminum foam core preform: After the three layers of ingredients are mixed evenly, they are laid in layers in a steel mold. After each layer is laid, it is pre-pressed with a pressure of 8MPa for 15min. The mold is then sent into a sintering furnace, argon gas is introduced, and the temperature is raised to 750℃ at a rate of 8℃ / min. It is held at this temperature for 4h for foaming and sintering. Then it is cooled to below 200℃ at a rate of 5℃ / min and removed to obtain the gradient aluminum foam blank. S2. Surface pretreatment: The mating surfaces of the upper and lower panels are ultrasonically cleaned with acetone solution at 25°C for 20 minutes to remove surface oil stains. Then, the mating surfaces are sandblasted with 120-mesh white corundum sand to achieve a surface roughness of 6.2μm. Finally, the upper and lower panels are immersed in 8% (w / w) dilute sulfuric acid solution for 8 minutes, washed with water until the pH reaches 7, and dried at 100°C. The same steps are used to pretreat the upper and lower mating surfaces of the gradient foam aluminum blank. S3. Composite connection: The pretreated upper panel, gradient aluminum foam blank and lower panel are stacked in sequence in a hot press. Epoxy modified acrylic adhesive is applied to the bonding surface. A pressure of 0.3MPa is applied, argon gas is introduced and the temperature is raised to 60℃. The temperature is maintained for 120 minutes to complete the curing. S4. Anti-corrosion treatment: After the composite structure is cooled to room temperature in the furnace, the shape is trimmed by milling. The trimmed structure is then immersed in potassium dichromate solution at 35°C for 15 minutes to form a passivation film. After being taken out and dried, a modified polyvinyl fluoride coating material is sprayed on and cured at 120°C for 60 minutes to finally obtain an ice-impact resistant gradient aluminum foam sandwich panel.

[0051] Comparative Example 1: The difference between this comparative example and Example 1 is that no modified titanium hydride foaming agent was used in this comparative example.

[0052] Comparative Example 2 differs from Example 2 in that epoxy-modified acrylate was not used in this comparative example.

[0053] Comparative Example 3 differs from Example 3 in that modified polyvinyl fluoride coating material was not used in this comparative example.

[0054] Performance testing: Performance tests were conducted on the products prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3. Ice impact peak force test: Prepare specimens according to the sandwich panel structure dimensions and make cylindrical ice balls; adjust the drop hammer impact testing machine, set the impact hammer mass to 5kg and the drop height to make the ice ball impact velocity reach 20m / s, fix the specimen with four corner fixed clamps and align the impact point; release the drop hammer to let the ice ball impact the center of the specimen, record the force-time curve in real time through a high-speed data acquisition system, extract the maximum impact force value, and take the arithmetic mean after 3 tests for each group. Test standard: ASTM D7136. Impact energy absorption density test: Prepare at least 3 parallel samples per group according to the sandwich panel structure dimensions, and pre-treat them by ultrasonic cleaning and sandblasting roughening; calibrate the drop hammer impact testing machine, set the impact energy to 1000J and the impact velocity to 20m / s, calibrate the force sensor and displacement measurement system, fix the sample with four corner support clamps and align the impact point; release the drop hammer so that the ice puck impacts the center of the sample, and record the force-time curve through the high-speed data acquisition system; integrate the curve over the impact duration to obtain the total absorbed energy, measure the sample volume and calculate the impact energy absorption density according to the formula, take 3 tests for each group and take the arithmetic mean, test according to: ASTM D7136. Interfacial shear strength test: The sandwich panel is processed into short beam specimens, with at least 3 parallel specimens per group. The specimens are polished to ensure that there are no initial defects at the interface and that the specimens are consistent with the actual pre-treatment state. The universal testing machine is calibrated with a 40mm span three-point bending support and a 5mm diameter loading head. The load sensor is calibrated and the loading speed is set to 1mm / min. The specimen is placed horizontally on the support, with the loading head facing the center. The load is applied at a uniform speed and the load-displacement curve is recorded. The load is stopped when the curve reaches an inflection point. The maximum load is extracted, and the interfacial shear strength is calculated according to the standard formula. Each group is tested 3 times and the arithmetic mean is taken. The test is based on ASTM C1363.

[0055] The obtained test data are recorded in Table 1 below:

[0056] By comparing and analyzing the relevant data in Table 1, it can be seen that the gradient aluminum foam sandwich panel prepared by the present invention using an ice-impact resistant gradient aluminum foam sandwich panel and its preparation method not only has a lower peak ice impact force, but also a higher impact energy absorption density and interfacial shear strength. This indicates that the ice-impact resistant gradient aluminum foam sandwich panel and its preparation method provided by the present invention have a broader market prospect and are more suitable for widespread application.

[0057] In the description of this specification, references to terms such as "an embodiment," "example," and "specific example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0058] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A gradient aluminum foam sandwich panel resistant to ice impact, characterized in that, The raw materials include the following parts by weight: 20-30 parts of industrial pure aluminum powder, 3-5 parts of modified titanium hydride foaming agent, 60-80 parts of metal material for the upper panel, 80-100 parts of metal material for the lower panel, 3-6 parts of epoxy modified acrylate adhesive, 30-42 parts of surface pretreatment material, and 12-20 parts of anti-corrosion material. The metal materials used for the upper and lower panels are Q690 high-strength steel, 6061 aluminum alloy or TC4 titanium alloy. The surface pretreatment material consists of 10-15 parts acetone solution, 5-7 parts white corundum sand, and 15-20 parts dilute sulfuric acid solution with a mass fraction of 5-8%. The anti-corrosion material consists of 8-12 parts of potassium dichromate solution with a mass fraction of 3-5% and 4-8 parts of modified polyvinyl fluoride coating material.

2. The ice-impact resistant gradient aluminum foam sandwich panel according to claim 1, characterized in that, The preparation steps of the modified titanium hydride are as follows: KH-550 ethanol solution is added to titanium hydride particles at a mass ratio of 1:(5-10), and stirred at 200r / min for 1-2h at 30-40℃ to graft KH-550 onto the particle surface, followed by rinsing with deionized water and drying at 80℃; the surface-functionalized titanium hydride is added to deionized water at a mass ratio of 1:40, heated to 80-90℃, and stirred at 300r / min to form a uniform suspension; Simultaneously prepare a 1 mol / L sodium silicate solution containing 2% polyvinyl alcohol and a buffer acid solution consisting of a 2 mol / L hydrochloric acid solution and a borax-sodium hydroxide buffer solution. Add the above-mentioned polyvinyl alcohol-containing sodium silicate solution and buffer acid solution simultaneously using two burettes at a rate of 40 mL / h. During the titration, continuously stir at 300 r / min to ensure uniform nucleation of silica on the surface of titanium hydride. After titration, continue stirring for 20-30 min, allow to cool naturally to room temperature, and age for 2-3 h. After filtration, wash 3-5 times with deionized water until neutral, and finally dry at 80-100℃ for 2-4 h to obtain silica-coated modified titanium hydride.

3. The ice-impact resistant gradient aluminum foam sandwich panel according to claim 2, characterized in that: In the KH-550 ethanol solution, the volume ratio of ethanol to deionized water is 9:1; in the 1 mol / L sodium silicate solution containing 2% polyvinyl alcohol, the volume ratio of sodium silicate solution to polyvinyl alcohol solution is 9:1; the pH of the borax-sodium hydroxide buffer solution is 9.5, and the hydrochloric acid solution and the borax-sodium hydroxide buffer solution are mixed at a volume ratio of 1:

1.

4. The ice-impact resistant gradient aluminum foam sandwich panel according to claim 1, characterized in that, The raw material of the foamed aluminum core layer is divided into three layers according to a gradient structure: the total mass ratio of the high-density layer near the top panel: the low-density layer in the middle: the high-density layer near the bottom panel is (25-35): (40-60): (15-25); wherein, the high-density layer near the top panel is composed of 92-95 parts of industrial pure aluminum powder and 5-8 parts of modified titanium hydrogenation foaming agent, the low-density layer in the middle panel is composed of 85-90 parts of industrial pure aluminum powder and 10-15 parts of modified titanium hydrogenation foaming agent, and the high-density layer near the bottom panel is composed of 90-93 parts of industrial pure aluminum powder and 7-10 parts of modified titanium hydrogenation foaming agent.

5. The ice-impact resistant gradient aluminum foam sandwich panel according to claim 1, characterized in that, The raw material composition of the epoxy-modified acrylate is as follows: 40-50 parts epoxy resin, 10-15 parts hydroxyethyl methacrylate, 20-25 parts butyl acrylate, 1-3 parts benzoyl peroxide initiator, 0.1-0.5 parts hydroquinone polymerization inhibitor, 1-3 parts KH-550, and 0.5-1.5 parts triethylamine catalyst.

6. The ice-impact resistant gradient aluminum foam sandwich panel according to claim 5, characterized in that, The preparation steps of the epoxy-modified acrylate are as follows: epoxy resin is added to a four-necked flask and heated to 80–100℃ to melt it, and stirred at a speed of 200–300 r / min; a mixture of hydroxyethyl methacrylate and butyl acrylate monomers is added dropwise at a dropping rate of 10–15 mL / h, and triethylamine catalyst is added at the same time. The reaction is kept at the temperature for 2–4 h to allow the epoxy groups to undergo a ring-opening grafting reaction with the hydroxyl / carboxyl groups of the acrylate to obtain an epoxy acrylate prepolymer; the prepolymer is cooled to 60–70℃, hydroquinone and KH-550 are added sequentially and stirred for 30 min, then benzoyl peroxide is added, and stirring is continued for 1 h until the mixture is uniform. The mixture is then cooled to room temperature to obtain the epoxy-modified acrylate adhesive.

7. The ice-impact resistant gradient aluminum foam sandwich panel according to claim 1, characterized in that, The modified polyvinyl fluoride coating material has the following raw material composition: 80-90 parts polyvinyl fluoride resin powder, 5-10 parts nano zinc oxide, 150-200 parts N,N-dimethylacetamide, and 1-2 parts polyether-modified polysiloxane leveling agent.

8. The ice-impact resistant gradient aluminum foam sandwich panel according to claim 7, characterized in that, The preparation method of the modified polyvinyl fluoride coating material is as follows: polyvinyl fluoride resin is added to N,N-dimethylacetamide, placed in a sealed constant temperature stirring device, heated to 120-130℃, and stirred at a speed of 300r / min for 50-80min to fully dissolve the resin and form a uniform and transparent polyvinyl fluoride resin solution. Add nano zinc oxide to the above resin solution, turn on an ultrasonic device with a power of 300-500W, and disperse for 30-60 minutes to ensure that the nano zinc oxide particles are not agglomerated and are uniformly distributed in the resin solution; add polyether modified polysiloxane leveling agent to the dispersed solution, continue stirring for 30 minutes, and then filter with a 200-mesh filter to obtain a modified polyvinyl fluoride coating material with a solid content of 40-50%.

9. The ice-impact resistant gradient aluminum foam sandwich panel according to claim 8, characterized in that, The nano-zinc oxide underwent modification treatment, specifically as follows: Anhydrous ethanol and deionized water were measured at a mass ratio of 9:1 and poured into a three-necked flask. Hydrochloric acid was added dropwise while stirring to adjust the pH to 4-5. Then, 1-5 parts of KH-550 were slowly added, and the mixture was stirred at 25-30℃ for 30-60 minutes to ensure complete hydrolysis of KH-550. 100 parts of nano-zinc oxide were added to the hydrolysate, and the temperature was raised to 50-60℃. The mixture was stirred at 200-300 r / min for 2-3 hours. The silanol groups generated from the hydrolysis of KH-550 underwent a condensation reaction with the hydroxyl groups on the surface of the nano-zinc oxide, causing KH-550 to be grafted onto the surface of the nano-zinc oxide. After the reaction, the mixture was centrifuged to collect the solid particles. The particles were washed 3-5 times with anhydrous ethanol and finally dried in a vacuum drying oven at 60-80℃ for 4-6 hours to complete the modification of the nano-zinc oxide.

10. A method for preparing an ice-impact resistant gradient aluminum foam sandwich panel, comprising the ice-impact resistant gradient aluminum foam sandwich panel according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Preparation of gradient aluminum foam core preform: After the three layers of ingredients are mixed evenly, they are laid in layers in a steel mold. After each layer is laid, it is pre-pressed with a pressure of 5-8 MPa for 10-15 min. The mold is then sent into a sintering furnace, argon gas is introduced, and the temperature is raised to 700-750℃ at a rate of 5-8℃ / min. The temperature is held for 2-4 h for foaming and sintering. Then, it is cooled to below 200℃ at a rate of 3-5℃ / min and removed to obtain the gradient aluminum foam blank. S2. Surface pretreatment: Use an acetone solution at 20-25℃ to ultrasonically clean the mating surfaces of the upper and lower panels for 15-20 minutes to remove surface oil stains. Then, use 80-120 mesh white corundum sand to sandblast the mating surfaces to achieve a surface roughness of 3.2-6.2μm. Finally, immerse the upper and lower panels in a 5-8% (w / w) dilute sulfuric acid solution for 5-8 minutes, wash with water until the pH reaches 6-7, and dry at 80-100℃. Use the same steps to pretreat the upper and lower mating surfaces of the gradient foam aluminum blank. S3. Composite connection: The pretreated upper panel, gradient aluminum foam blank and lower panel are stacked in sequence in a hot press. Epoxy modified acrylic adhesive is applied to the bonding surface. A pressure of 0.1-0.3MPa is applied, argon gas is introduced and the temperature is raised to 50-60℃. The temperature is maintained for 90-120 minutes to complete the curing. S4. Anti-corrosion treatment: After the composite structure is cooled to room temperature in the furnace, the shape is trimmed by milling. The trimmed structure is then immersed in potassium dichromate solution at 25-35℃ for 10-15 minutes to form a passivation film. After being taken out and dried, a modified polyvinyl fluoride coating material is sprayed on and cured at 100-120℃ for 40-60 minutes to finally obtain an ice-impact resistant gradient aluminum foam sandwich panel.

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