Metal panel, door body machining method and refrigerator

Abstract

The invention provides a metal panel, a door body machining method and a refrigerator, the metal panel comprises a panel base plate and a film layer, and the panel base plate is a composite plate formed by combining at least two metal materials; the film layer covers the panel substrate, the film layer is a titanium dioxide nano film, and the titanium dioxide nano film is prepared through anodic oxidation. The titanium dioxide nano film is prepared through anodic oxidation and has a permanent antibacterial effect, so that the problem of low antibacterial timeliness is solved.

Description

Technical Field

[0001] The present application relates to the field of material technology, and in particular to a metal panel, a door processing method and a refrigerator. Background Art

[0002] The metal panel of the refrigerator door is the interface that is in direct contact with the outside world. The metal panel uses steel plate as the base material, which has high strength, good processing performance and stable physical properties.

[0003] The metal panel of the refrigerator door body uses steel plate as the base material, and the surface of the steel plate is decorated. Specifically, the two surface treatment methods used in the market are PCM (Pre-Coated Metal) pre-coated steel plate and VCM (VeneerCoated Metal) coated steel plate. Both treatment methods can provide a good appearance effect for the refrigerator panel. Among them, PCM forms a coating by directly applying the paint to the surface of the steel plate and curing it, while VCM forms a coating by hot pressing a plastic film on the surface of the steel plate.

[0004] To enhance the antibacterial effect of the panel, antibacterial agents are added to the coating or film layer. However, when silver zinc ions are used as antibacterial components, the antibacterial properties may gradually weaken over time, resulting in low antibacterial effectiveness. Summary of the invention

[0005] The present application provides a metal panel, a door processing method and a refrigerator to solve the problem of low antibacterial effectiveness.

[0006] In a first aspect, the present application provides a metal panel, comprising:

[0007] A panel substrate, wherein the panel substrate is a composite plate formed by combining at least two metal materials;

[0008] The film layer is covered on the panel substrate, and the film layer is a titanium dioxide nanofilm, and the titanium dioxide nanofilm is prepared by anodizing.

[0009] In some feasible embodiments, the panel substrate includes:

[0010] A first metal layer, wherein the material of the first metal layer is steel, and the steel includes cold-rolled steel;

[0011] A second metal layer, wherein the second metal layer covers the first metal layer, the second metal layer is made of titanium, and the film layer covers the second metal layer.

[0012] In some feasible embodiments, the thickness of the metal panel is the first thickness, the thickness of the first metal layer is 50-90% of the first thickness, the thickness of the second metal layer is 10-50% of the first thickness, and the thickness of the film layer is 10-50 nm.

[0013] In some feasible embodiments, it also includes:

[0014] An ultraviolet excitation layer is coated on the surface of the film layer, and the material of the ultraviolet excitation layer is a zinc sulfide suspension or a silver nanoparticle dispersion.

[0015] In a second aspect, the present application provides a door body processing method, comprising:

[0016] Prepare a panel substrate, wherein the panel substrate is a composite plate formed by combining at least two metal materials;

[0017] preparing a film layer, wherein the film layer is a titanium dioxide nanofilm prepared by anodizing;

[0018] Covering the film layer on the panel base layer to form a metal panel;

[0019] The metal panel is made into a door body through a roll-rolling process.

[0020] In some feasible embodiments, the panel substrate includes a first metal layer and a second metal layer;

[0021] The method of preparing a panel substrate comprises:

[0022] The panel substrate is prepared by rolling a first metal layer and a second metal layer. The first metal layer is made of steel, including cold-rolled steel. The second metal layer is made of titanium.

[0023] In some feasible embodiments, the preparation of the film layer includes:

[0024] Anodizing is performed on the second metal layer to form a titanium dioxide nanofilm, and the anodizing temperature is 200-300°C.

[0025] In some feasible embodiments, the performing anodizing on the second metal layer to form a titanium dioxide nanofilm includes:

[0026] Prepare an electrolyte containing rare earth ions, wherein the electrolyte containing rare earth ions is a phosphoric acid or sulfuric acid solution added with cerium nitrate or lanthanum nitrate, and the concentration of the cerium nitrate or lanthanum nitrate is 0.01-0.1 mol / L;

[0027] Determine an anode and a cathode, wherein the anode is the second metal layer, and the cathode is stainless steel or platinum;

[0028] The electrolyte containing rare earth ions is added into the anodizing tank to form a titanium dioxide nanofilm.

[0029] In some feasible embodiments, the step of covering the film layer on the panel base layer to form a metal panel further includes:

[0030] preparing a photosensitizer solution, wherein the photosensitizer solution is a zinc sulfide suspension or a silver nanoparticle dispersion;

[0031] Covering the film layer on the panel base layer to form a panel substrate;

[0032] A photosensitizer solution is spin-coated on the panel substrate to form a metal panel, the spin-coating speed is 2500-3500 rpm, and the time is 20-40 seconds.

[0033] In a third aspect, the present application provides a refrigerator, comprising: a box body and a door body, wherein the box body is connected to the door body, and the door body is a door body processed by the door body processing method.

[0034] It can be seen from the above technical solutions that the present application provides a metal panel, a door processing method and a refrigerator, wherein the metal panel includes a panel substrate and a film layer, wherein the panel substrate is a composite plate formed by combining at least two metal materials; the film layer is covered on the panel substrate, and the film layer is a titanium dioxide nanofilm, which is prepared by anodizing. The titanium dioxide nanofilm is prepared by anodizing and has a permanent antibacterial effect to solve the problem of low antibacterial timeliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 A schematic diagram of the structure of a metal panel provided in an embodiment of the present application;

[0037] Figure 2 A flow chart of the door body processing method provided in an embodiment of the present application.

[0038] Illustration Description:

[0039] Among them, 100 is a first metal layer, 200 is a second metal layer, and 300 is a film layer. DETAILED DESCRIPTION

[0040] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.

[0041] PCM pre-coated steel sheet and VCM coated steel sheet are two surface treatment methods. PCM pre-coated steel sheet is made by pre-coating a layer of paint containing pigments and protective ingredients on the surface of the steel sheet, and then baking and curing it. It is low-cost, colorful and easy to process. VCM coated steel sheet, on the other hand, is made by laminating a layer of film with patterns or colors on the surface of the steel sheet through high temperature and high pressure, which can provide more delicate and rich visual effects and higher weather resistance. Metal panels also have functional properties, such as antibacterial, wear-resistant, scratch-resistant, fingerprint-resistant and pollution-resistant. Among them, the antibacterial function is achieved by adding antibacterial agents, such as silver-zinc ion antibacterial agents, to the coating or film layer. However, when silver-zinc ions are used as antibacterial ingredients, the antibacterial performance may gradually weaken over time, resulting in low antibacterial timeliness.

[0042] To solve the above problems, see Figure 1 Some embodiments of the present application provide a metal panel, including: a panel substrate, which is a composite panel generated by combining at least two metal materials.

[0043] In some embodiments, the panel substrate includes a first metal layer 100 and a second metal layer 200 . The first metal layer 100 is made of steel, including cold-rolled steel. The second metal layer 200 covers the first metal layer 100 , and the second metal layer 200 is made of titanium.

[0044] Among them, cold rolled steel is steel made by the cold rolling process, which is carried out at room temperature to give the steel higher strength and more precise dimensions. Cold rolled steel has high strength and hardness while maintaining good surface quality and dimensional accuracy. Titanium is a silvery-white, lightweight metal with good corrosion resistance, high strength and low density.

[0045] Rolling cladding is an advanced material processing technology that combines two or more different metals together through plastic deformation. The rolling cladding process uses the plastic deformation ability of metals under certain conditions, such as high temperature and high pressure, to form a metallurgical bond between the two metals at the interface, thereby obtaining a composite material with unique properties. The rolling cladding process is to roll metal sheets under high temperature and high pressure to cause two or more layers of metal to produce plastic deformation on the contact surface, thereby achieving metallurgical bonding between the interfaces. The rolling cladding process allows the composite material to retain the advantages of each single layer of material while overcoming the shortcomings of a single material.

[0046] In some embodiments, the thickness of the metal panel is the first thickness, the thickness of the first metal layer 100 is 50-90% of the first thickness, the thickness of the second metal layer 200 is 10-50% of the first thickness, and the thickness of the film layer 300 is 10-50 nm.

[0047] The first thickness is 0.3-0.5 mm, for example, 0.3, 0.35, 0.4, 0.45, 0.5. Within this thickness range, the metal panel can provide good strength and toughness to ensure the structural stability of the refrigerator door, while being able to resist a certain degree of external impact. Although metal has good thermal conductivity, at the first thickness, the metal panel is combined with the insulation layer inside the refrigerator, which can effectively reduce the loss of cold air and improve the insulation effect of the refrigerator.

[0048] The thickness of the cold-rolled steel is 50-90% of the first thickness, for example, 50%, 60%, 70%, 80%, 90%. The relatively large cold-rolled steel can provide good mechanical strength to ensure that the panel is not easily deformed during use, especially when the door body is foamed, it can withstand the pressure of the internal foam without bending. Although the cold-rolled steel layer accounts for a large proportion, since the overall panel thickness is only 0.3-0.5mm, it can still maintain the characteristics of lightweight and is suitable for refrigerators.

[0049] The thickness of titanium metal is 10%-50% of the first thickness, for example, 10%, 20%, 30%, 40%, 50%. Titanium metal has a lower density and higher strength, which can reduce the weight while ensuring the strength of the panel, making the metal panel lighter and easier to carry. Although the titanium metal layer accounts for a small proportion, titanium metal has excellent corrosion resistance and can maintain a good condition even in a humid environment. It can resist the erosion of sweat, moisture and other media and extend the service life of the refrigerator. In addition, the titanium metal layer can also give the refrigerator door a different texture and appearance to meet the different needs of customers and enhance the user experience.

[0050] The thickness of the carbon dioxide nanofilm is 10 to 50 nm, for example, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm. TiO2 has photocatalytic activity and can decompose organic pollutants under light conditions, playing a self-cleaning role. The TiO2 nanofilm can inhibit bacterial growth and provide an antibacterial effect. The dense TiO2 film increases the hardness of the surface and reduces scratches and wear. In addition, the film layer 300 is thin, which hardly affects the visual effect while providing protection.

[0051] The second metal layer 200 is covered with a film layer 300, which is a titanium dioxide nanofilm, which is prepared by anodizing. The titanium dioxide nanofilm is a nano-scale film composed of titanium dioxide (TiO2), which has good optical properties, weather resistance and self-cleaning function. The titanium dioxide nanofilm has the functions of antibacterial, air purification, pollution resistance and carbon dioxide capture.

[0052] Anodizing is an electrochemical method that applies voltage in an electrolyte to cause an oxidation reaction on the surface of titanium metal to form a dense titanium dioxide (TiO2) film. This process is carried out in a solution containing acidic or alkaline substances, and the electrolyte includes sulfuric acid, phosphoric acid, oxalic acid, etc.

[0053] Exemplarily, a cleaned and pretreated titanium metal layer is prepared to ensure that the surface is clean and free of oil and dirt, and a suitable electrolyte solution is selected according to the characteristics and thickness of the film layer 300 to be formed. Titanium metal is used as an anode, immersed in an electrolyte, and a certain voltage is applied. At the anode, the titanium metal loses electrons and combines with oxygen ions to form a titanium dioxide film. The thickness and characteristics of the film layer 300 are controlled by adjusting parameters such as voltage, current density, temperature, and processing time. After the treatment is completed, the film layer 300 needs to be cleaned and dried, and heat treatment can also be performed to improve the adhesion and hardness of the film layer 300.

[0054] The TiO2 film formed by anodization is a porous structure, and the pore size can be controlled by adjusting the process parameters. By changing the electrolyte composition or processing conditions, the film layer 300 can present different colors due to the light interference effect. The titanium dioxide film has good corrosion resistance, photocatalytic activity, antibacterial properties and biocompatibility.

[0055] In the process of using the metal panel, in order to improve the timeliness of antibacterial and activate the antibacterial effect of titanium dioxide, in some embodiments, the surface of the film layer 300 is coated with an ultraviolet excitation layer, and the material of the ultraviolet excitation layer is a zinc sulfide suspension or a silver nanoparticle dispersion. Adding a layer of ultraviolet excitation layer on the titanium dioxide nanofilm can improve the photocatalytic activity and antibacterial effect of titanium dioxide under natural light by applying different material layers.

[0056] The metal panel plate provided in this embodiment has high strength. When the door body is foamed, there is no need to add a felt reinforcement plate on the back of the door shell, which reduces materials and processes. The surface is a titanium dioxide nanofilm, which has the functions of antibacterial, air purification, pollution resistance, and carbon dioxide capture. It is prepared by anodizing and has a certain thickness. It has better antibacterial and other functions and has a permanent antibacterial effect. The titanium dioxide nanofilm also has the texture of real metal, which increases the texture of the door body.

[0057] Based on the above metal panel, see Figure 2 Some embodiments of the present application also provide a door body processing method, including:

[0058] S100: preparing a panel substrate.

[0059] The panel substrate is a composite plate generated by combining at least two metal materials; the panel substrate includes a first metal layer 100 and a second metal layer 200; the first metal layer 100 and the second metal layer 200 are subjected to a rolling composite process to prepare the panel substrate, the material of the first metal layer 100 is steel, including cold-rolled steel, and the material of the second metal layer 200 is titanium.

[0060] Cold-rolled steel and titanium metal are selected as the substrates, and the two are combined through a rolling composite process to form a composite plate. Ensure that the thickness of the cold-rolled steel layer is 50%-90%, and the thickness of the titanium metal layer is 10%-50%. The titanium metal layer in the composite plate is anodized to form a layer of titanium dioxide nanofilm, and the thickness of the film layer is controlled between 10-50nm.

[0061] The steps of combining cold-rolled steel and titanium metal through rolling composite process are, for example, first cleaning and polishing the surfaces of cold-rolled steel and titanium metal to remove the oxide scale, grease and other impurities on the surface, ensuring that the surfaces of the two layers of metal are clean and have good flatness. The treated cold-rolled steel and titanium metal are stacked, with the cold-rolled steel as the base material and the titanium metal as the covering layer.

[0062] The materials can be preheated before or after stacking as needed. Preheating helps reduce friction between interfaces and promotes diffusion of atoms between metals, thereby increasing bonding strength. The stacked materials are sent to the rolling mill for rolling. During the rolling process, the materials are compressed under high pressure, causing plastic deformation at the interface of the two layers of metal to form a close contact. After rolling, the materials need to be cooled and may need to be annealed to eliminate internal stress and improve the mechanical properties of the materials.

[0063] S200: preparing a film layer.

[0064] The film layer 300 is a titanium dioxide nanofilm prepared by anodization. In some embodiments, anodization is performed on the second metal layer 200 to form the titanium dioxide nanofilm. The anodization temperature is 200-300°C.

[0065] For example, the titanium substrate (second metal layer 200) is cleaned, cleaned with acetone, ethanol or other solvents to remove grease and impurities, and rinsed with deionized water and dried. An anodizing solution (e.g., 0.5M H3PO4) is prepared, and a titanium sheet is used as an anode and placed in an electrolytic cell, with a platinum sheet or a stainless steel sheet as a cathode. The anodizing voltage (20-60V), current density (0.5-2.0A / dm2 ), perform anodizing treatment at a temperature of 200-300°C for 30 minutes to 1 hour, remove the titanium sheet, wash it with deionized water and dry it to form a titanium dioxide nanofilm.

[0066] S300: Covering the film layer on the panel base layer to form a metal panel.

[0067] Titanium dioxide itself is a highly efficient photocatalytic material that can generate photogenerated electron-hole pairs under ultraviolet irradiation. These electrons and holes can react with surrounding water and oxygen to generate free radicals with strong oxidizing ability, thereby decomposing organic pollutants and killing bacteria. However, pure titanium dioxide is only active under ultraviolet light (wavelength <387nm), which limits its use under daily visible light conditions. In some embodiments, a photosensitizer solution is prepared, and the photosensitizer solution is a zinc sulfide suspension or a silver nanoparticle dispersion; the film layer 300 is covered on the panel base layer to form a panel substrate; the photosensitizer solution is spin-coated on the panel substrate to form a metal panel, and the spin-coating speed is 2500-3500rpm, and the time is 20-40s.

[0068] By doping with rare earth elements, cerium (Ce) and lanthanum (La), the light response range of TiO2 can be expanded, and photocatalytic effects can be produced even under visible light conditions.

[0069] Among them, cerium, as a multivalent rare earth element, can effectively inhibit the recombination of electron-hole pairs (that is, when the generated electrons and holes quickly recombine, the photocatalytic efficiency decreases). The multivalent state of cerium helps to capture electrons and holes, prolong the life of free radicals, and thus improve the photocatalytic efficiency. The doping of lanthanum can change the crystal structure of titanium dioxide, allowing it to absorb light in a wider spectral range. In addition, lanthanum can also increase the reactivity of the titanium dioxide surface and promote the generation of free radicals in the photocatalytic reaction.

[0070] The photocatalytic properties of titanium dioxide impart antibacterial capabilities because the free radicals it generates can destroy bacterial cell walls, cell membranes, and biomacromolecules such as DNA. Rare earth doping can extend the active period of the photocatalytic reaction, allowing titanium dioxide to maintain its antibacterial effect for a longer period of time, and this is effective for use in low light or indoor environments. The high-energy free radicals generated after doping with rare earth elements are more active and can quickly and effectively kill bacteria and other microorganisms. The incorporation of rare earth elements not only enhances the photocatalytic and antibacterial properties, but also improves the overall structure and electronic properties of the titanium dioxide film.

[0071] Rare earth doping can improve the conductivity of titanium dioxide film, allowing photogenerated electrons to transfer to the film surface faster, thereby accelerating the reaction rate. Rare earth elements can also slow down the recombination of electron and hole pairs, further improving the photocatalytic efficiency. The incorporation of rare earth elements helps stabilize the crystal structure of titanium dioxide, so that it still has good photocatalytic and antibacterial functions under high temperature or harsh environment.

[0072] Exemplarily, an electrolyte containing rare earth ions is prepared, the electrolyte is a phosphoric acid or sulfuric acid solution, an appropriate amount of cerium or lanthanum salt, such as cerium nitrate or lanthanum nitrate, a titanium sheet is used as the anode (positive electrode), and a stainless steel sheet or platinum sheet is used as the cathode (negative electrode). The electrolyte is poured into the anodizing tank to ensure that the electrode is completely immersed. The voltage is adjusted to an appropriate value such as 20-60V, and the current density is controlled at 0.5-2.0A / dm 2 . Perform anodization, which usually lasts for 30 minutes to 1 hour. Control the reaction temperature between 200-300℃ and maintain a constant temperature.

[0073] During the anodization process, rare earth ions will migrate through the electrolyte and embed into the formed titanium dioxide nanofilm. A multi-step anodization method can be adopted, that is, preliminary anodization is first carried out in a solution without rare earth doping, and then the semi-finished product is moved into a solution containing rare earth ions for secondary anodization.

[0074] After anodization is completed, the titanium sheet is taken out and rinsed with deionized water to remove the residual electrolyte on the surface. Drying treatment is carried out using hot air or vacuum drying equipment. The oxide film is heat treated (e.g. annealing at 300°C to 500°C) to improve the crystallinity and stability of the film, and at the same time, it can promote the uniform distribution and shaping of rare earth elements and improve the doping effect.

[0075] S400: The metal panel is rolled into a door body through a roll-bending process.

[0076] Rolling is a processing method that uses one or more pairs of rotating rollers to plastically deform metal sheets. By adjusting the gap and pressure between the rollers, the thickness and shape of the sheet can be changed. In this process, textures can also be formed on the sheet through specific roller surface patterns. Rolling can be used to form a textured touch on the panel surface. Exemplarily, a metal panel with a titanium dioxide nanofilm is fed into a rolling mill, and the panel is gradually bent into a desired shape, such as a refrigerator door, by a preset roller set.

[0077] Cold-rolled steel as a substrate provides good mechanical strength and rigidity, and can withstand external pressure and impact without deformation. The titanium metal layer not only increases the corrosion resistance of the material, but also enhances the structural strength of the panel due to the high strength ratio of titanium itself. The titanium dioxide nanofilm can provide additional protection against corrosion and wear.

[0078] The composite use of three materials enables the entire panel to achieve a good balance in strength and toughness. The combination of cold-rolled steel and titanium metal layers is tightly connected through the rolling composite process. This structural design not only makes the panel have high rigidity, but also absorbs and disperses stress to a certain extent, reducing the possibility of deformation caused by external forces. During the manufacturing process, the hardness and uniformity of the panel surface can be further improved through technical means such as anodizing and roller pressing.

[0079] The metal panel provided in this embodiment can make the door body without additional support during the foaming process. For example, adding a felt reinforcement plate on the back of the door shell can maintain good shape stability and mechanical properties.

[0080] Based on the above-mentioned door body processing method, some embodiments of the present application also provide a refrigerator, including: a box body and a door body, the box body and the door body are connected, and the door body is a door body processed by the door body processing method.

[0081] It is understood that the refrigerator provided in the embodiment of the present application is a refrigeration device, which at least includes a refrigeration system, a cooling system, a control system and a cabinet to achieve refrigeration and operation. Among them, the refrigeration system is used to produce a refrigeration effect, the cooling system is used to maintain a low temperature environment, the control system is used to control the temperature and humidity in the refrigerator, etc., and the cabinet is used to provide storage space. It is understood that the refrigeration system, the cooling system, and the control system include specific components that can achieve the above functions.

[0082] In some embodiments, the refrigeration system includes a compressor, a condenser, an evaporator, and a throttling device. Among them, the compressor is used to compress the refrigerant gas, increase the pressure and temperature, and thus promote the flow of the refrigerant in the system. During the compression process, the refrigerant changes from a low-pressure and high-temperature gas to a high-pressure and high-temperature gas, thereby producing a refrigeration effect. The condenser is used to cool the high-temperature and high-pressure gas discharged from the compressor into a liquid state. The heat is released through the heat sink, and the refrigerant gas is converted into a liquid state, ready to enter the next step of the refrigeration cycle. The evaporator is used to absorb heat in the refrigeration system. The refrigerant evaporates from a liquid state to a gas state in the evaporator, absorbing heat from the surrounding environment, thereby achieving the purpose of lowering the temperature inside the refrigerator. The throttling device may include an expansion valve and a capillary tube, which are used to adjust the flow rate of the refrigerant, reduce its pressure, and make it become a low-temperature and low-pressure gas-liquid mixed state, ready to enter the evaporator.

[0083] In some embodiments, the cooling system includes a fan connected to the evaporator. The fan circulates air in the compartments, such as the freezer and refrigerator, to transfer heat to the evaporator, helping to maintain a low temperature environment inside the refrigerator.

[0084] It should be noted that the above example is merely a simple division of the functions of the refrigerator and does not constitute a limitation on the specific structure of the refrigerator in the embodiment of the present application.

[0085] The present application provides a metal panel, a door processing method and a refrigerator, wherein the metal panel includes a panel substrate and a film layer 300, wherein the panel substrate is a composite plate formed by combining at least two metal materials; the film layer 300 is covered on the panel substrate, and the film layer 300 is a titanium dioxide nanofilm, which is prepared by anodizing. The titanium dioxide nanofilm is prepared by anodizing and has a permanent antibacterial effect to solve the problem of low antibacterial timeliness.

[0086] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.

Claims

1. A metal panel, characterized in that: include: A panel substrate, wherein the panel substrate is a composite plate formed by combining at least two metal materials; The film layer is covered on the panel substrate, and the film layer is a titanium dioxide nanofilm, and the titanium dioxide nanofilm is prepared by anodizing.

2. The metal panel according to claim 1, characterized in that: The panel substrate comprises: A first metal layer, wherein the material of the first metal layer is steel, and the steel includes cold-rolled steel; A second metal layer, wherein the second metal layer covers the first metal layer, the second metal layer is made of titanium, and the film layer covers the second metal layer.

3. The metal panel according to claim 2, characterized in that: The thickness of the metal panel is the first thickness, the thickness of the first metal layer is 50-90% of the first thickness, the thickness of the second metal layer is 10-50% of the first thickness, and the thickness of the film layer is 10-50 nm.

4. The metal panel according to claim 1, characterized in that: Also includes: An ultraviolet excitation layer is coated on the surface of the film layer, and the material of the ultraviolet excitation layer is a zinc sulfide suspension or a silver nanoparticle dispersion.

5. A door body processing method, characterized in that: include: Prepare a panel substrate, wherein the panel substrate is a composite plate formed by combining at least two metal materials; preparing a film layer, wherein the film layer is a titanium dioxide nanofilm prepared by anodizing; Covering the film layer on the panel base layer to form a metal panel; The metal panel is made into a door body through a roll-rolling process.

6. The door body processing method according to claim 5, characterized in that: The panel substrate includes a first metal layer and a second metal layer; The method of preparing a panel substrate comprises: The panel substrate is prepared by rolling a first metal layer and a second metal layer. The first metal layer is made of steel, including cold-rolled steel, and the second metal layer is made of titanium.

7. The door body processing method according to claim 6, characterized in that: The preparation of the film layer comprises: Anodizing is performed on the second metal layer to form a titanium dioxide nanofilm, and the anodizing temperature is 200-300°C.

8. The door body processing method according to claim 7, characterized in that: The step of performing anodizing on the second metal layer to form a titanium dioxide nanofilm comprises: Prepare an electrolyte containing rare earth ions, wherein the electrolyte containing rare earth ions is a phosphoric acid or sulfuric acid solution added with cerium nitrate or lanthanum nitrate, and the concentration of the cerium nitrate or lanthanum nitrate is 0.01-0.1 mol / L; Determine an anode and a cathode, wherein the anode is the second metal layer, and the cathode is stainless steel or platinum; The electrolyte containing rare earth ions is added into the anodizing tank to form a titanium dioxide nanofilm.

9. The door body processing method according to claim 5, characterized in that: The step of covering the film layer on the panel base layer to form a metal panel also includes: preparing a photosensitizer solution, wherein the photosensitizer solution is a zinc sulfide suspension or a silver nanoparticle dispersion; Covering the film layer on the panel base layer to form a panel substrate; A photosensitizer solution is spin-coated on the panel substrate to form a metal panel, wherein the spin-coating speed is 2500-3500 rpm and the time is 20-40 seconds.

10. A refrigerator, characterized in that: include: A box body and a door body, wherein the box body is connected to the door body, and the door body is processed by the door body processing method described in any one of claims 5-9.

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