A zinc alloy and a method of making the same

Abstract

The application discloses a zinc alloy and a preparation method thereof, and comprises a zinc alloy base material and a polypyrrole cerium oxide composite film; the outer surface of the zinc alloy base material has a microporous structure, and the microporous structure of the zinc alloy base material is coated with a layer of polypyrrole cerium oxide composite film; the zinc alloy base material is made of raw materials with the following mass percentages: 0.05-0.12% of aluminum, 0.1-0.3% of manganese, 0.8-1.5% of copper, 0.01-0.1% of titanium, 0.01-0.05% of rhenium, and the balance of zinc. The zinc alloy and the preparation method thereof have the advantages that the zinc alloy base material is prepared by adopting a melting casting-equiaxed angle extrusion-heat rolling-cold rolling combined process, the microporous structure is prepared on the surface of the zinc alloy base material, and the microporous structure is coated with a layer of polypyrrole cerium oxide composite film, so that the final zinc alloy has good mechanical properties and good corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of zinc alloy technology, and in particular to a zinc alloy and its preparation method. Background Technology

[0002] Zinc alloys are alloys composed of zinc as a base and other elements added, commonly including aluminum, copper, magnesium, cadmium, lead, and titanium. Zinc alloys possess advantages such as good fluidity, excellent mechanical properties, short production processes, and low energy consumption, leading to their increasingly widespread application worldwide. Zinc alloys are widely used in packaging, construction, electronics, and automotive industries.

[0003] Currently, zinc alloy thin plates are usually made by processes such as smelting and casting, extrusion, and rolling. Zinc alloy thin plates are widely used in building panels, electronic appliances, communication products, automotive parts and other fields. However, existing zinc alloy thin plates have the following defects: (1) Insufficient mechanical properties, with low strength and creep strength; (2) Limited corrosion resistance. Zinc alloy thin plates are often placed on the surface of products, so there are certain requirements for the corrosion resistance of zinc alloy thin plates. The passivation film (such as phosphate) on the surface of zinc alloy thin plates is prone to pitting corrosion in humid or salt spray environments. Directly spraying anti-corrosion film on the surface of zinc alloy thin plates also has problems such as insufficient adhesion, not being environmentally friendly, and generating waste during the coating process; (3) Difficult to process and form. Zinc alloy thin plates are prone to cracking during cold rolling, and edge cracks or surface wrinkles are prone to occur during cold rolling. Summary of the Invention

[0004] In view of this, the present invention proposes a zinc alloy and a method for preparing the same.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A zinc alloy includes a zinc alloy substrate and a polypyrrole cerium oxide composite film; the outer surface of the zinc alloy substrate has a microporous structure, and a layer of polypyrrole cerium oxide composite film is coated on the microporous structure of the zinc alloy substrate.

[0007] The zinc alloy substrate is made from the following raw materials in the following mass percentages: aluminum 0.05-0.12%, manganese 0.1-0.3%, copper 0.8-1.5%, titanium 0.01-0.1%, rhenium 0.01-0.05%, with the balance being zinc.

[0008] Furthermore, the thickness of the polypyrrole cerium oxide composite film is 0.5–1 μm.

[0009] A method for preparing a zinc alloy includes the following steps:

[0010] S1. Smelting and Casting

[0011] Prepare zinc ingots with a purity of 99.99%, aluminum ingots with a purity of 99.99%, copper granules with a purity of 99.99%, titanium granules with a purity of 99.9%, manganese powder with a purity of 99.9%, and rhenium powder with a purity of 99.99%; before smelting, clean the impurities and oxides from the surface of each raw material.

[0012] According to the formula, zinc ingots, aluminum ingots, copper granules, titanium granules, manganese powder, and rhenium powder are placed in a vacuum induction furnace under argon protection and heated until the raw materials are completely melted and uniformly mixed. The melt is then kept at 450-500℃ for 60 minutes.

[0013] A refining agent is added to the melt for refining. The amount of refining agent added is 0.1-0.3% of the mass of the mixed melt. The refining time is 15-20 minutes. The refining process is always carried out under an argon atmosphere to remove surface scum and degas the liquid. The refined liquid is then poured into a preheated graphite mold and cooled in air to obtain an alloy ingot.

[0014] S2, rapid plastic deformation

[0015] The alloy ingot was placed in an annealing furnace and held at 280℃ for 6–12 hours for homogenization annealing, and then air-cooled to room temperature.

[0016] The equal diameter angular extrusion die consists of two interconnected channels with identical cross-sections. Molybdenum disulfide is applied as a lubricant to the inner walls of the channels. Both the extrusion die and the alloy ingot are preheated. The preheated alloy ingot is then placed within the inner channel of the extrusion die. Under the pressure of the press, the alloy ingot is pressed in through the vertical channel of the extrusion die and out through the horizontal channel, completing the equal diameter angular extrusion. After each extrusion, the alloy ingot rotates 90° to enter the next pass, maintaining the same direction, and then the next equal diameter angular extrusion is performed. This process is repeated from one to six passes. Through multiple passes of equal diameter angular extrusion, the grain size is refined to the submicron level.

[0017] Intermediate annealing is performed between multiple passes of equal diameter angular extrusion. During intermediate annealing, the alloy is placed in an annealing furnace and held at 100–250°C for 5–20 minutes, with argon gas purging for protection. After 6 passes of equal diameter angular extrusion, final annealing is performed. During final annealing, the alloy is placed in an annealing furnace and held at 100–250°C for 1–10 minutes.

[0018] S3, hot rolled

[0019] The alloy ingot, after rapid plastic deformation, is placed in a vacuum resistance furnace and heated to 150–250°C, held for 60–90 minutes to ensure uniform temperature. The heated ingot is then fed into a two-roll reversible hot rolling mill for hot rolling at a speed of 0.5 m / s, an initial rolling temperature of 220–250°C, and a first pass reduction of 15–20%. Multiple passes are then performed, with subsequent passes gradually reducing the reduction from 15–20% to 10% and increasing the rolling speed to 1.2 m / s, achieving a total deformation of 70–80%. The resulting alloy sheet thickness is 2–4 mm. Argon gas is introduced during the hot rolling process to prevent oxidation.

[0020] After each hot rolling pass, a fine water mist is sprayed onto the surface of the alloy sheet to cool it to room temperature. Argon gas is introduced for protection during cooling. After the alloy sheet has accumulated 15-20% deformation, intermediate annealing is performed. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 150-200℃ for 30-45 minutes. Argon gas is introduced for protection during intermediate annealing.

[0021] S4, cold rolled

[0022] The hot-rolled alloy sheet is pickled in pickling solution and then dried. Then the dried alloy sheet is initially annealed. During the initial annealing, the alloy sheet is placed in an annealing furnace and held at 150-200℃ for 90-120 minutes. Argon gas is introduced for protection during the initial annealing.

[0023] The alloy sheet after initial annealing is fed into a four-roll cold rolling mill for rolling at a rolling speed of 0.3 m / s. The first pass reduction is 8-10%, and multiple passes of hot rolling are performed in sequence. In subsequent passes, the reduction is gradually reduced from 10% to 8%, and the rolling speed is gradually increased to 0.8 m / s to achieve a total deformation of 50-70%. After cold rolling, the thickness of the zinc alloy substrate is 1-2 mm.

[0024] After the alloy sheet has accumulated 15-20% deformation, it undergoes intermediate annealing. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 150±10℃ for 45-60 minutes, with argon gas protection introduced during the intermediate annealing. After cold rolling, the alloy sheet undergoes final annealing, which is held at 120±10℃ for 45-75 minutes, with argon gas protection introduced during the final annealing.

[0025] During the cold rolling process, finely atomized nano-lubricant is sprayed onto both sides of the alloy sheet and onto the rolls of the four-roll cold rolling mill.

[0026] S5, Surface Treatment

[0027] The cold-rolled zinc alloy substrate was ultrasonically cleaned with alcohol and then dried in a vacuum dryer. A picosecond laser was used to ablate a honeycomb micropore array structure on the surface of the alloy sheet by grating scanning in an argon atmosphere. After the picosecond laser processed the micropore array structure, the zinc alloy substrate was ultrasonically cleaned with alcohol again and dried in a vacuum dryer.

[0028] Cerium ammonium nitrate was mixed with citric acid, dissolved in deionized water, and the pH was adjusted to 4-5. The mixture was then heated in a water bath at 80-85℃ to form a transparent sol, thus preparing cerium oxide sol. Pyrrole monomer was added to the cerium oxide sol, and ammonium persulfate solution was added dropwise as an oxidant. The mixture was stirred at room temperature for 6-12 hours to polymerize the polypyrrole composite.

[0029] Finally, the composite sol is coated onto the surface of the zinc alloy substrate by dip-coating or spin-coating. The zinc alloy substrate is placed in a vacuum resistance furnace and heated to 80-120°C for 1 hour to form a polypyrrole cerium oxide composite film on the surface of the zinc alloy substrate.

[0030] Furthermore, in step S1, before using the graphite mold, a grinding machine is used to remove surface impurities, and then it is cleaned with deionized water and alcohol in sequence and dried.

[0031] The graphite mold described in step S1 is preheated at 200°C for 20 minutes.

[0032] Furthermore, the refining agent in step S1 is hexachloroethane.

[0033] Furthermore, in step S2, the inner angle of the extrusion die is 90° and the outer angle is 20°;

[0034] In step S2, the extrusion die is preheated to 120-200°C and held at 120-200°C for 5-15 minutes; in step S2, the alloy ingot is preheated to 150-250°C.

[0035] Furthermore, in step S4, the pickling solution is sulfuric acid or hydrochloric acid solution, the concentration of the pickling solution is 5% to 10%, the temperature of the pickling solution is 40 to 60°C, and the pickling time is 15 to 20 minutes.

[0036] The nano-lubricant is a nano-graphite emulsion.

[0037] Furthermore, in step S5, the wavelength of the picosecond laser is 10–64 nm, the power is 10–20 W, and the repetition frequency is 50 kHz.

[0038] Furthermore, in step S5, the pore size of the micropores is 10–20 μm, and the spacing between adjacent micropores is 100–200 μm.

[0039] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a zinc alloy substrate prepared using a combined process of smelting and casting, equal-diameter angular extrusion, hot rolling, and cold rolling. A microporous structure is prepared on the surface of the zinc alloy substrate, and a polypyrrole cerium oxide composite film is coated onto the microporous structure. This results in a zinc alloy with excellent mechanical properties and good corrosion resistance, making it suitable for applications in building panels, electronics, communication products, and automotive parts. The polypyrrole cerium oxide composite film is also environmentally friendly as an anti-corrosion layer. Pyrrole monomer raw materials are relatively widely available and environmentally friendly, and can be biodegraded under certain conditions. Cerium oxide is a rare earth oxide with good chemical stability and is environmentally friendly. When the polypyrrole cerium oxide composite film is coated on the surface of the zinc alloy substrate, it does not release harmful gases and substances such as formaldehyde and benzene, and does not pollute the surrounding environment. Detailed Implementation

[0040] 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.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. Example 1

[0043] A zinc alloy includes a zinc alloy substrate and a polypyrrole cerium oxide composite film; the outer surface of the zinc alloy substrate has a microporous structure, and a layer of polypyrrole cerium oxide composite film is coated on the microporous structure of the zinc alloy substrate.

[0044] The zinc alloy substrate is made from the following raw materials in weight percentages: aluminum 0.08%, manganese 0.2%, copper 1.2%, titanium 0.05%, rhenium 0.02%, and zinc 98.45%. The thickness of the polypyrrole cerium oxide composite film is 0.5–1 μm.

[0045] A method for preparing a zinc alloy includes the following steps:

[0046] S1. Smelting and Casting

[0047] Prepare zinc ingots with a purity of 99.99%, aluminum ingots with a purity of 99.99%, copper granules with a purity of 99.99%, titanium granules with a purity of 99.9%, manganese powder with a purity of 99.9%, and rhenium powder with a purity of 99.99%; before smelting, clean the impurities and oxides from the surface of each raw material.

[0048] According to the specified ratio, zinc ingots, aluminum ingots, copper granules, titanium granules, manganese powder, and rhenium powder are placed in a vacuum induction furnace under argon protection and heated until the raw materials are completely melted and uniformly mixed. The melt is held at 550°C for 60 minutes. A refining agent, hexachloroethane, is added to the melt for refining at a rate of 0.3% of the mass of the mixed melt. The refining time is 20 minutes, and the refining process is carried out under an argon atmosphere throughout. Surface slag is removed and degassing is performed to obtain a refined liquid, which is then poured into a preheated graphite mold. The casting speed is controlled during casting, starting slowly, increasing in speed in the middle, and then slowing down again towards the end. Before use, the graphite mold is polished to remove surface impurities, then cleaned with deionized water and alcohol in sequence and dried. The graphite mold is preheated at 200°C for 20 minutes. The alloy ingot is obtained by air cooling.

[0049] S2, rapid plastic deformation

[0050] The alloy ingot was placed in an annealing furnace and held at 280℃ for 12 hours for homogenization annealing, and then air-cooled to room temperature.

[0051] The equal-diameter angular extrusion die consists of two interconnected channels with identical cross-sections. The inner angle of the die is 90° and the outer angle is 20°. Molybdenum disulfide is applied as a lubricant to the inner wall of the channel. The die and the alloy ingot are preheated separately. The die is preheated to 150°C and held at 150°C for 10 minutes, while the ingot is preheated to 200°C. After preheating, the ingot is placed in the inner channel of the die. Under the pressure of the press, the ingot is pressed in through the vertical channel and out through the horizontal channel, completing the equal-diameter angular extrusion. After each extrusion, the ingot rotates 90° to enter the next pass, maintaining the same direction, and then the next pass of equal-diameter angular extrusion is performed. This process is repeated from one pass to six passes. Through multiple passes of equal-diameter angular extrusion, the grain size is refined to the submicron level.

[0052] Intermediate annealing is performed between multiple equal diameter angular extrusions. During intermediate annealing, the alloy is placed in an annealing furnace and held at 250°C for 10 minutes. Argon gas is introduced for protection during intermediate annealing. After 6 equal diameter angular extrusions, final annealing is performed. During final annealing, the alloy is placed in an annealing furnace and held at 200°C for 5 minutes.

[0053] S3, hot rolled

[0054] The alloy ingot, after rapid plastic deformation, is placed in a vacuum resistance furnace and heated to 250°C, held for 60 minutes to ensure uniform temperature. The heated ingot is then fed into a two-roll reversible hot rolling mill for hot rolling at a speed of 0.5 m / s, an initial rolling temperature of 250°C, and a first pass reduction of 20%. Multiple passes are then performed, with the reduction in each subsequent pass gradually decreasing from 20% to 10%, and the rolling speed gradually increasing to 1.2 m / s, achieving a total deformation of 80%. The resulting alloy sheet is 4 mm thick. Argon gas is introduced during the hot rolling process to prevent oxidation.

[0055] After each hot rolling pass, a fine water mist is sprayed onto the surface of the alloy sheet to cool it to room temperature. Argon gas is introduced for protection during cooling. After the alloy sheet has accumulated 20% deformation, intermediate annealing is performed. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 200°C for 30 minutes. Argon gas is introduced for protection during intermediate annealing.

[0056] S4, cold rolled

[0057] The hot-rolled alloy sheet is placed in a pickling solution for pickling. The pickling solution is a sulfuric acid or hydrochloric acid solution with a concentration of 8%, a temperature of 40°C, and a pickling time of 15 minutes. After pickling, it is dried. Then, the dried alloy sheet is subjected to initial annealing. During initial annealing, the alloy sheet is placed in an annealing furnace and held at 200°C for 120 minutes. Argon gas is introduced for protection during the initial annealing.

[0058] The alloy sheet after initial annealing is fed into a four-roll cold rolling mill for rolling at a rolling speed of 0.3 m / s. The first pass has a reduction of 10%, and multiple passes of hot rolling are performed in sequence. In subsequent passes, the reduction is gradually reduced from 10% to 8%, and the rolling speed is gradually increased to 0.8 m / s to achieve a total deformation of 50%. After cold rolling, the zinc alloy substrate thickness is 2 mm.

[0059] After the alloy sheet has accumulated 15% deformation, it is subjected to intermediate annealing. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 150±10℃ for 60 minutes. Argon gas is introduced for protection during intermediate annealing. After cold rolling, the alloy sheet is subjected to final annealing. During final annealing, it is held at 120±10℃ for 60 minutes. Argon gas is introduced for protection during final annealing.

[0060] During the cold rolling process, a finely atomized nano-lubricant is sprayed onto both sides of the alloy sheet and onto the rolls of the four-roll cold rolling mill; the nano-lubricant is a nano-graphite emulsion.

[0061] S5, Surface Treatment

[0062] The cold-rolled zinc alloy substrate was ultrasonically cleaned with alcohol and then dried in a vacuum dryer. A picosecond laser was used to ablate a honeycomb micropore array structure on the surface of the alloy sheet by grating scanning in an argon atmosphere. After the picosecond laser processed the micropore array structure, the zinc alloy substrate was ultrasonically cleaned with alcohol again and dried in a vacuum dryer.

[0063] 4.2g of cerium ammonium nitrate was mixed with 2g of citric acid, dissolved in 50mL of deionized water, and the pH was adjusted to 4-5. The mixture was then heated in an 80℃ water bath to form a transparent sol, thus preparing cerium oxide sol. 4.5g of ammonium persulfate was dissolved in 50mL of deionized water to prepare ammonium persulfate solution. 1mL of pyrrole monomer was added to the cerium oxide sol, and ammonium persulfate solution was added dropwise as an oxidant. The mixture was stirred at room temperature for 12h to polymerize the polypyrrole composite.

[0064] Finally, the composite sol was coated onto the surface of the zinc alloy substrate by dip-coating or spin-coating. The zinc alloy substrate was placed in a vacuum resistance furnace and heated to 110°C for 1 hour to form a polypyrrole cerium oxide composite film on the surface of the zinc alloy substrate. Example 2

[0065] Compared with Example 1, the difference lies in: a zinc alloy comprising a zinc alloy substrate and a polypyrrole cerium oxide composite film; the outer surface of the zinc alloy substrate has a microporous structure, and a layer of polypyrrole cerium oxide composite film is coated on the microporous structure of the zinc alloy substrate; the zinc alloy substrate is made of the following raw materials in the following mass percentages: aluminum 0.05%, manganese 0.2%, copper 0.8%, titanium 0.05%, rhenium 0.02%, and zinc 98.88%. The thickness of the polypyrrole cerium oxide composite film is 0.5–1 μm.

[0066] The preparation method of the zinc alloy is the same as that in Example 1. Example 3

[0067] Compared with Example 1, the difference lies in: a zinc alloy comprising a zinc alloy substrate and a polypyrrole cerium oxide composite film; the outer surface of the zinc alloy substrate has a microporous structure, and a layer of polypyrrole cerium oxide composite film is coated on the microporous structure of the zinc alloy substrate; the zinc alloy substrate is made of the following raw materials in the following mass percentages: aluminum 0.1%, manganese 0.3%, copper 1.0%, titanium 0.1%, rhenium 0.05%, and zinc 98.45%. The thickness of the polypyrrole cerium oxide composite film is 0.5–1 μm.

[0068] The preparation method of the zinc alloy is the same as that in Example 1. Example 4

[0069] Compared with Example 1, the difference lies in: a zinc alloy comprising a zinc alloy substrate and a polypyrrole cerium oxide composite film; the outer surface of the zinc alloy substrate has a microporous structure, and a layer of polypyrrole cerium oxide composite film is coated on the microporous structure of the zinc alloy substrate; the zinc alloy substrate is made of the following raw materials in the following mass percentages: aluminum 0.12%, manganese 0.1%, copper 1.5%, titanium 0.01%, rhenium 0.01%, and zinc 98.26%. The thickness of the polypyrrole cerium oxide composite film is 0.5–1 μm.

[0070] The preparation method of the zinc alloy is the same as that in Example 1.

[0071] Comparative Example 1

[0072] A method for preparing pure zinc includes the following steps:

[0073] S1. Smelting and Casting

[0074] Prepare zinc ingots with a purity of 99.99%; clean the impurities and oxides from the surface of the zinc ingots before smelting;

[0075] The zinc ingots are heated in a vacuum induction furnace under argon protection until the raw materials are completely melted and uniformly mixed. The melt is held at 550°C for 60 minutes and then poured into a preheated graphite mold. Before use, the graphite mold is polished to remove surface impurities, then cleaned with deionized water and alcohol and dried. The graphite mold is preheated at 200°C for 20 minutes. The zinc ingots are obtained by air cooling.

[0076] S2, hot rolled

[0077] The zinc ingot, after rapid plastic deformation, is placed in a vacuum resistance furnace and heated to 250°C, held for 60 minutes to ensure uniform temperature. The heated ingot is then fed into a two-roll reversible hot rolling mill for hot rolling at a speed of 0.5 m / s, an initial rolling temperature of 250°C, and a first-pass reduction of 20%. Multiple hot rolling passes are performed, with the reduction in each subsequent pass gradually decreasing from 20% to 10%, and the rolling speed gradually increasing to 1.2 m / s, achieving a total deformation of 80%. The resulting zinc sheet is 4 mm thick. Argon gas is introduced during the hot rolling process to prevent oxidation.

[0078] After each hot rolling pass, a fine water mist is sprayed onto the surface of the zinc sheet to cool it to room temperature. Argon gas is introduced for protection during cooling. After the zinc sheet has accumulated 20% deformation, intermediate annealing is performed. During intermediate annealing, the zinc sheet is placed in an annealing furnace and held at 200°C for 30 minutes. Argon gas is introduced for protection during intermediate annealing.

[0079] Comparative Example 2

[0080] A zinc alloy, comprising a zinc alloy substrate;

[0081] The zinc alloy substrate is made from the following raw materials in weight percentages: aluminum 0.08%, manganese 0.2%, copper 1.2%, titanium 0.05%, rhenium 0.02%, and zinc 98.45%.

[0082] A method for preparing a zinc alloy includes the following steps:

[0083] S1. Smelting and Casting

[0084] Prepare zinc ingots with a purity of 99.99%, aluminum ingots with a purity of 99.99%, copper granules with a purity of 99.99%, titanium granules with a purity of 99.9%, manganese powder with a purity of 99.9%, and rhenium powder with a purity of 99.99%; before smelting, clean the impurities and oxides from the surface of each raw material.

[0085] According to the specified ratio, zinc ingots, aluminum ingots, copper granules, titanium granules, manganese powder, and rhenium powder are placed in a vacuum induction furnace under argon protection and heated until the raw materials are completely melted and uniformly mixed. The melt is held at 550°C for 60 minutes. A refining agent, hexachloroethane, is added to the melt for refining at a rate of 0.3% of the mass of the mixed melt. The refining time is 20 minutes, and the refining process is carried out under an argon atmosphere throughout. Surface slag is removed and degassing is performed to obtain a refined liquid, which is then poured into a preheated graphite mold. The casting speed is controlled during casting, starting slowly, increasing in speed in the middle, and then slowing down again towards the end. Before use, the graphite mold is polished to remove surface impurities, then cleaned with deionized water and alcohol in sequence and dried. The graphite mold is preheated at 200°C for 20 minutes. The alloy ingot is obtained by air cooling.

[0086] S2, hot rolled

[0087] The alloy ingot, after rapid plastic deformation, is placed in a vacuum resistance furnace and heated to 250°C, held for 60 minutes to ensure uniform temperature. The heated ingot is then fed into a two-roll reversible hot rolling mill for hot rolling at a speed of 0.5 m / s, an initial rolling temperature of 250°C, and a first pass reduction of 20%. Multiple passes are then performed, with the reduction in each subsequent pass gradually decreasing from 20% to 10%, and the rolling speed gradually increasing to 1.2 m / s, achieving a total deformation of 80%. The resulting alloy sheet is 4 mm thick. Argon gas is introduced during the hot rolling process to prevent oxidation.

[0088] After each hot rolling pass, a fine water mist is sprayed onto the surface of the alloy sheet to cool it to room temperature. Argon gas is introduced for protection during cooling. After the alloy sheet has accumulated 20% deformation, intermediate annealing is performed. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 200°C for 30 minutes. Argon gas is introduced for protection during intermediate annealing.

[0089] Comparative Example 3

[0090] A zinc alloy, comprising a zinc alloy substrate;

[0091] The zinc alloy substrate is made from the following raw materials in weight percentages: aluminum 0.08%, manganese 0.2%, copper 1.2%, titanium 0.05%, rhenium 0.02%, and zinc 98.45%.

[0092] A method for preparing a zinc alloy includes the following steps:

[0093] S1. Smelting and Casting

[0094] Prepare zinc ingots with a purity of 99.99%, aluminum ingots with a purity of 99.99%, copper granules with a purity of 99.99%, titanium granules with a purity of 99.9%, manganese powder with a purity of 99.9%, and rhenium powder with a purity of 99.99%; before smelting, clean the impurities and oxides from the surface of each raw material.

[0095] According to the specified ratio, zinc ingots, aluminum ingots, copper granules, titanium granules, manganese powder, and rhenium powder are placed in a vacuum induction furnace under argon protection and heated until the raw materials are completely melted and uniformly mixed. The melt is held at 550°C for 60 minutes. A refining agent, hexachloroethane, is added to the melt for refining at a rate of 0.3% of the mass of the mixed melt. The refining time is 20 minutes, and the refining process is carried out under an argon atmosphere throughout. Surface slag is removed and degassing is performed to obtain a refined liquid, which is then poured into a preheated graphite mold. The casting speed is controlled during casting, starting slowly, increasing in speed in the middle, and then slowing down again towards the end. Before use, the graphite mold is polished to remove surface impurities, then cleaned with deionized water and alcohol in sequence and dried. The graphite mold is preheated at 200°C for 20 minutes. The alloy ingot is obtained by air cooling.

[0096] S2, rapid plastic deformation

[0097] The alloy ingot was placed in an annealing furnace and held at 280℃ for 12 hours for homogenization annealing, and then air-cooled to room temperature.

[0098] The equal-diameter angular extrusion die consists of two interconnected channels with identical cross-sections. The inner angle of the die is 90° and the outer angle is 20°. Molybdenum disulfide is applied as a lubricant to the inner wall of the channel. The die and the alloy ingot are preheated separately. The die is preheated to 150°C and held at 150°C for 10 minutes, while the ingot is preheated to 200°C. After preheating, the ingot is placed in the inner channel of the die. Under the pressure of the press, the ingot is pressed in through the vertical channel and out through the horizontal channel, completing the equal-diameter angular extrusion. After each extrusion, the ingot rotates 90° to enter the next pass, maintaining the same direction, and then the next pass of equal-diameter angular extrusion is performed. This process is repeated from one pass to six passes. Through multiple passes of equal-diameter angular extrusion, the grain size is refined to the submicron level.

[0099] Intermediate annealing is performed between multiple equal diameter angular extrusions. During intermediate annealing, the alloy is placed in an annealing furnace and held at 250°C for 10 minutes. Argon gas is introduced for protection during intermediate annealing. After 6 equal diameter angular extrusions, final annealing is performed. During final annealing, the alloy is placed in an annealing furnace and held at 200°C for 5 minutes.

[0100] S3, hot rolled

[0101] The alloy ingot, after rapid plastic deformation, is placed in a vacuum resistance furnace and heated to 250°C, held for 60 minutes to ensure uniform temperature. The heated ingot is then fed into a two-roll reversible hot rolling mill for hot rolling at a speed of 0.5 m / s, an initial rolling temperature of 250°C, and a first pass reduction of 20%. Multiple passes are then performed, with the reduction in each subsequent pass gradually decreasing from 20% to 10%, and the rolling speed gradually increasing to 1.2 m / s, achieving a total deformation of 80%. The resulting alloy sheet is 4 mm thick. Argon gas is introduced during the hot rolling process to prevent oxidation.

[0102] After each hot rolling pass, a fine water mist is sprayed onto the surface of the alloy sheet to cool it to room temperature. Argon gas is introduced for protection during cooling. After the alloy sheet has accumulated 20% deformation, intermediate annealing is performed. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 200°C for 30 minutes. Argon gas is introduced for protection during intermediate annealing.

[0103] Comparative Example 4

[0104] A zinc alloy, comprising a zinc alloy substrate;

[0105] The zinc alloy substrate is made from the following raw materials in weight percentages: aluminum 0.08%, manganese 0.2%, copper 1.2%, titanium 0.05%, rhenium 0.02%, and zinc 98.45%.

[0106] A method for preparing a zinc alloy includes the following steps:

[0107] S1. Smelting and Casting

[0108] Prepare zinc ingots with a purity of 99.99%, aluminum ingots with a purity of 99.99%, copper granules with a purity of 99.99%, titanium granules with a purity of 99.9%, manganese powder with a purity of 99.9%, and rhenium powder with a purity of 99.99%; before smelting, clean the impurities and oxides from the surface of each raw material.

[0109] According to the specified ratio, zinc ingots, aluminum ingots, copper granules, titanium granules, manganese powder, and rhenium powder are placed in a vacuum induction furnace under argon protection and heated until the raw materials are completely melted and uniformly mixed. The melt is held at 550°C for 60 minutes. A refining agent, hexachloroethane, is added to the melt for refining at a rate of 0.3% of the mass of the mixed melt. The refining time is 20 minutes, and the refining process is carried out under an argon atmosphere throughout. Surface slag is removed and degassing is performed to obtain a refined liquid, which is then poured into a preheated graphite mold. The casting speed is controlled during casting, starting slowly, increasing in speed in the middle, and then slowing down again towards the end. Before use, the graphite mold is polished to remove surface impurities, then cleaned with deionized water and alcohol in sequence and dried. The graphite mold is preheated at 200°C for 20 minutes. The alloy ingot is obtained by air cooling.

[0110] S2, rapid plastic deformation

[0111] The alloy ingot was placed in an annealing furnace and held at 280℃ for 12 hours for homogenization annealing, and then air-cooled to room temperature.

[0112] The equal-diameter angular extrusion die consists of two interconnected channels with identical cross-sections. The inner angle of the die is 90° and the outer angle is 20°. Molybdenum disulfide is applied as a lubricant to the inner wall of the channel. The die and the alloy ingot are preheated separately. The die is preheated to 150°C and held at 150°C for 10 minutes, while the ingot is preheated to 200°C. After preheating, the ingot is placed in the inner channel of the die. Under the pressure of the press, the ingot is pressed in through the vertical channel and out through the horizontal channel, completing the equal-diameter angular extrusion. After each extrusion, the ingot rotates 90° to enter the next pass, maintaining the same direction, and then the next pass of equal-diameter angular extrusion is performed. This process is repeated from one pass to six passes. Through multiple passes of equal-diameter angular extrusion, the grain size is refined to the submicron level.

[0113] Intermediate annealing is performed between multiple equal diameter angular extrusions. During intermediate annealing, the alloy is placed in an annealing furnace and held at 250°C for 10 minutes. Argon gas is introduced for protection during intermediate annealing. After 6 equal diameter angular extrusions, final annealing is performed. During final annealing, the alloy is placed in an annealing furnace and held at 200°C for 5 minutes.

[0114] S3, cold rolled

[0115] The hot-rolled alloy sheet is placed in a pickling solution for pickling. The pickling solution is a sulfuric acid or hydrochloric acid solution with a concentration of 8%, a temperature of 40°C, and a pickling time of 15 minutes. After pickling, it is dried. Then, the dried alloy sheet is subjected to initial annealing. During initial annealing, the alloy sheet is placed in an annealing furnace and held at 200°C for 120 minutes. Argon gas is introduced for protection during the initial annealing.

[0116] The alloy sheet after initial annealing is fed into a four-roll cold rolling mill for rolling at a rolling speed of 0.3 m / s. The first pass has a reduction of 10%, and multiple passes of hot rolling are performed in sequence. In subsequent passes, the reduction is gradually reduced from 10% to 8%, and the rolling speed is gradually increased to 0.8 m / s to achieve a total deformation of 50%. After cold rolling, the zinc alloy substrate thickness is 2 mm.

[0117] After the alloy sheet has accumulated 15% deformation, it is subjected to intermediate annealing. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 150±10℃ for 60 minutes. Argon gas is introduced for protection during intermediate annealing. After cold rolling, the alloy sheet is subjected to final annealing. During final annealing, it is held at 120±10℃ for 60 minutes. Argon gas is introduced for protection during final annealing.

[0118] During the cold rolling process, a finely atomized nano-lubricant is sprayed onto both sides of the alloy sheet and onto the rolls of the four-roll cold rolling mill; the nano-lubricant is a nano-graphite emulsion.

[0119] Comparative Example 5

[0120] A zinc alloy, comprising a zinc alloy substrate;

[0121] The zinc alloy substrate is made from the following raw materials in weight percentages: aluminum 0.08%, manganese 0.2%, copper 1.2%, titanium 0.05%, rhenium 0.02%, and zinc 98.45%.

[0122] A method for preparing a zinc alloy includes the following steps:

[0123] S1. Smelting and Casting

[0124] Prepare zinc ingots with a purity of 99.99%, aluminum ingots with a purity of 99.99%, copper granules with a purity of 99.99%, titanium granules with a purity of 99.9%, manganese powder with a purity of 99.9%, and rhenium powder with a purity of 99.99%; before smelting, clean the impurities and oxides from the surface of each raw material.

[0125] According to the specified ratio, zinc ingots, aluminum ingots, copper granules, titanium granules, manganese powder, and rhenium powder are placed in a vacuum induction furnace under argon protection and heated until the raw materials are completely melted and uniformly mixed. The melt is held at 550°C for 60 minutes. A refining agent, hexachloroethane, is added to the melt for refining at a rate of 0.3% of the mass of the mixed melt. The refining time is 20 minutes, and the refining process is carried out under an argon atmosphere throughout. Surface slag is removed and degassing is performed to obtain a refined liquid, which is then poured into a preheated graphite mold. The casting speed is controlled during casting, starting slowly, increasing in speed in the middle, and then slowing down again towards the end. Before use, the graphite mold is polished to remove surface impurities, then cleaned with deionized water and alcohol in sequence and dried. The graphite mold is preheated at 200°C for 20 minutes. The alloy ingot is obtained by air cooling.

[0126] S2, rapid plastic deformation

[0127] The alloy ingot was placed in an annealing furnace and held at 280℃ for 12 hours for homogenization annealing, and then air-cooled to room temperature.

[0128] The equal-diameter angular extrusion die consists of two interconnected channels with identical cross-sections. The inner angle of the die is 90° and the outer angle is 20°. Molybdenum disulfide is applied as a lubricant to the inner wall of the channel. The die and the alloy ingot are preheated separately. The die is preheated to 150°C and held at 150°C for 10 minutes, while the ingot is preheated to 200°C. After preheating, the ingot is placed in the inner channel of the die. Under the pressure of the press, the ingot is pressed in through the vertical channel and out through the horizontal channel, completing the equal-diameter angular extrusion. After each extrusion, the ingot rotates 90° to enter the next pass, maintaining the same direction, and then the next pass of equal-diameter angular extrusion is performed. This process is repeated from one pass to six passes. Through multiple passes of equal-diameter angular extrusion, the grain size is refined to the submicron level.

[0129] Intermediate annealing is performed between multiple equal diameter angular extrusions. During intermediate annealing, the alloy is placed in an annealing furnace and held at 250°C for 10 minutes. Argon gas is introduced for protection during intermediate annealing. After 6 equal diameter angular extrusions, final annealing is performed. During final annealing, the alloy is placed in an annealing furnace and held at 200°C for 5 minutes.

[0130] S3, hot rolled

[0131] The alloy ingot, after rapid plastic deformation, is placed in a vacuum resistance furnace and heated to 250°C, held for 60 minutes to ensure uniform temperature. The heated ingot is then fed into a two-roll reversible hot rolling mill for hot rolling at a speed of 0.5 m / s, an initial rolling temperature of 250°C, and a first pass reduction of 20%. Multiple passes are then performed, with the reduction in each subsequent pass gradually decreasing from 20% to 10%, and the rolling speed gradually increasing to 1.2 m / s, achieving a total deformation of 80%. The resulting alloy sheet is 4 mm thick. Argon gas is introduced during the hot rolling process to prevent oxidation.

[0132] After each hot rolling pass, a fine water mist is sprayed onto the surface of the alloy sheet to cool it to room temperature. Argon gas is introduced for protection during cooling. After the alloy sheet has accumulated 20% deformation, intermediate annealing is performed. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 200°C for 30 minutes. Argon gas is introduced for protection during intermediate annealing.

[0133] S4, cold rolled

[0134] The hot-rolled alloy sheet is placed in a pickling solution for pickling. The pickling solution is a sulfuric acid or hydrochloric acid solution with a concentration of 8%, a temperature of 40°C, and a pickling time of 15 minutes. After pickling, it is dried. Then, the dried alloy sheet is subjected to initial annealing. During initial annealing, the alloy sheet is placed in an annealing furnace and held at 200°C for 120 minutes. Argon gas is introduced for protection during the initial annealing.

[0135] The alloy sheet after initial annealing is fed into a four-roll cold rolling mill for rolling at a rolling speed of 0.3 m / s. The first pass has a reduction of 10%, and multiple passes of hot rolling are performed in sequence. In subsequent passes, the reduction is gradually reduced from 10% to 8%, and the rolling speed is gradually increased to 0.8 m / s to achieve a total deformation of 50%. After cold rolling, the zinc alloy substrate thickness is 2 mm.

[0136] After the alloy sheet has accumulated 15% deformation, it is subjected to intermediate annealing. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 150±10℃ for 60 minutes. Argon gas is introduced for protection during intermediate annealing. After cold rolling, the alloy sheet is subjected to final annealing. During final annealing, it is held at 120±10℃ for 60 minutes. Argon gas is introduced for protection during final annealing.

[0137] During the cold rolling process, a finely atomized nano-lubricant is sprayed onto both sides of the alloy sheet and onto the rolls of the four-roll cold rolling mill; the nano-lubricant is a nano-graphite emulsion.

[0138] According to GB / T 228.1-2010 "Metallic materials, tensile testing—Part 1: Tests at room temperature," tensile strength, yield strength, and elongation of the specimens were measured using a universal tensile testing machine at room temperature. The zinc alloy specimens prepared in Examples 1-4, the zinc alloy specimens prepared in Comparative Examples 2-5, and the pure zinc specimen prepared in Comparative Example 1 were all cut by wire cutting. All specimens were polished with sandpaper to remove oxide scale and processing defects from the specimen surface. Three sets of parallel specimens were taken from the zinc alloy specimens in Examples 1-4, three sets of parallel specimens from the zinc alloy specimens in Comparative Examples 2-5, and three sets of parallel specimens from the pure zinc specimen in Comparative Example 1 to ensure the accuracy of the mechanical property data. The test results are shown in Table 1.

[0139] According to GB / T 231.1-2009 "Metallic Materials - Brinell Hardness Test - Part 1: Test Method", the Vickers hardness of the samples was measured at room temperature using a Vickers hardness tester. The zinc alloy samples prepared in Examples 1-4, the zinc alloy samples prepared in Comparative Examples 2-5, and the pure zinc sample prepared in Comparative Example 1 were all cut by wire cutting. All samples were polished with sandpaper to remove oxide scale and processing defects from the sample surface. Three parallel sets of samples were taken from the zinc alloy samples in Examples 1-4, three parallel sets of samples from the zinc alloy samples in Comparative Examples 2-5, and three parallel sets of samples from the pure zinc sample in Comparative Example 1 to ensure the accuracy of the mechanical property data. The test results are shown in Table 1.

[0140] The zinc alloy samples prepared in Example 1 and the zinc alloy samples prepared in Comparative Example 5 were placed in a 3.5% NaCl solution for electrochemical corrosion tests. The electrochemical tests were performed on an electrochemical workstation using a three-electrode system. The zinc alloy samples prepared in Examples 1-4, the pure zinc sample prepared in Comparative Example 1, and the zinc alloy samples prepared in Comparative Examples 2-5 were used as working electrodes, with a platinum sheet electrode as the auxiliary electrode and a saturated calomel electrode as the reference electrode. The electrolyte was a 3.5% NaCl solution, and the sample temperature was controlled at room temperature. The Tafel curves of each zinc alloy electrode sample were measured.

[0141] After the open-circuit potential stabilized, electrochemical impedance spectroscopy was performed with a scanning range of OCP ± 250 mV and a scanning frequency of 1 mV / s. The change in current with potential was recorded. All samples were polished with sandpaper to remove oxide scale and processing defects from the sample surface. Three parallel groups of zinc alloy samples were taken for Example 1 and Comparative Example 5 to ensure the accuracy of the corrosion resistance data. The test results are shown in Table 2.

[0142] The zinc alloy samples prepared in Example 1 and the zinc alloy samples prepared in Comparative Example 5 were fixed on a non-metallic support in the salt spray test chamber to avoid contact with the metal parts of the chamber. A 5% sodium chloride solution was used as the spray medium and continuous spraying was carried out at a temperature of 35°C and a humidity of 95% or higher. The start time was recorded and the test was paused every 24 hours. The surface condition was recorded and the corrosion of each sample surface could be observed with a magnifying glass or microscope to observe whether there were rust spots, peeling, or other phenomena.

[0143] In Example 1, three sets of parallel samples were taken from the zinc alloy sample, and in Comparative Example 5, three sets of parallel samples were also taken from the zinc alloy sample to ensure the accuracy of the observation results. Observation shows that the zinc alloy sample in Example 1 has slight pitting corrosion on its surface, while the zinc alloy sample in Comparative Example 5 has a uniform white rust covering its surface, with localized red rust.

[0144] Table 1. Mechanical property test results of Examples 1-4 and Comparative Examples 1-5

[0145] project Yield strength (MPa) Ultimate tensile strength (MPa) Elongation (%) Vickers hardness (HV) Example 1 425 477 10 204 Example 2 427 481 11 206 Example 3 418 465 10 199 Example 4 412 473 10 193 Comparative Example 1 72 125 38 43 Comparative Example 2 220 273 22 102 Comparative Example 3 323 391 13 139 Comparative Example 4 382 447 8 178 Comparative Example 5 399 452 11 185

[0146] Table 2. Corrosion resistance test results of Example 1 and Comparative Example 5

[0147] project Corrosion potential (V vs. SCE) <![CDATA[Corrosion current density (μA / cm 2 )]]> Corrosion rate (mm / y) Comparative Example 5 ﹣1.02 26 0.36 Example 1 ﹣0.9 1.7 0.012

[0148] It can be seen that the zinc alloys prepared in Examples 1-4 have excellent mechanical properties and good corrosion resistance.

[0149] Polypyrrole cerium oxide composite film is also relatively environmentally friendly as an anti-corrosion film layer; the raw materials of pyrrole monomer are relatively widely available and environmentally friendly, and can be biodegraded under certain conditions; while cerium oxide is a rare earth oxide with good chemical stability and is environmentally friendly; when polypyrrole cerium oxide composite film is coated on the surface of zinc alloy substrate, it will not release harmful gases and substances such as formaldehyde and benzene, and will not cause pollution to the surrounding environment.

[0150] In the constant diameter angular extrusion process of Examples 1-4: when the zinc alloy ingot passes through the channel inflection point, it is subjected to shear force and undergoes strong shear deformation, resulting in an ideal fine grain structure; the size and shape of the zinc alloy ingot remain almost unchanged before and after extrusion, and it can be extruded multiple times, with the strain accumulating and superimposed, thereby obtaining a large total strain, achieving the effect of grain refinement, and realizing strong plastic deformation.

[0151] In the hot rolling-cold rolling-drawing process of Examples 1-4: Hot rolling provides basic grain refinement and forming capabilities. This is because heating puts the zinc alloy in a high-temperature state, which enhances atomic activity, increases the plasticity of the material, and reduces deformation resistance, making the alloy easier to plastically process. The rolling deformation at high temperature can break and refine the coarse grains in the cast structure, promote the full dissolution and uniform distribution of the second phase particles in the alloy, improve the microstructure of the alloy, and improve the overall performance of the alloy. Through hot rolling, zinc alloy ingots can be quickly processed into plates with a certain thickness, width and length, providing suitable billets for subsequent cold rolling and other processing.

[0152] Cold rolling is a rolling process carried out at room temperature or lower temperatures. It can further process hot-rolled zinc alloys into plates with high dimensional accuracy and surface smoothness. During cold rolling, the zinc alloy undergoes cold deformation, and the dislocation density increases significantly, resulting in work hardening, which significantly improves the alloy's strength, hardness, and other mechanical properties. Cold rolling can make the zinc alloy surface smoother and brighter, eliminating defects such as surface oxide scale and pitting that may occur during hot rolling, improving the surface quality of the alloy, and enhancing its corrosion resistance and appearance. Cold rolling combined with multi-pass annealing prevents brittle fracture.

[0153] The microporous structure on the surface of the zinc alloy substrate, and the polypyrrole-cerium oxide composite film coated on the microporous structure, significantly improve the overall corrosion resistance of the zinc alloy, meeting the application requirements of harsh corrosive environments. Therefore, the zinc alloys prepared in Examples 1-4 are superior to those prepared in Comparative Examples 2-5 in terms of strength and corrosion rate.

[0154] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A zinc alloy, characterized in that, The invention comprises a zinc alloy substrate and a polypyrrole cerium oxide composite film. The zinc alloy substrate is prepared using a combined process of melting and casting, equal-diameter angular extrusion, hot rolling, and cold rolling. A microporous structure is formed on the surface of the zinc alloy substrate, and a polypyrrole cerium oxide composite film is coated onto the microporous structure. The thickness of the polypyrrole cerium oxide composite film is 0.5–1 μm. The polypyrrole cerium oxide composite film is formed through the following process: For surface treatment, the cold-rolled zinc alloy substrate was ultrasonically cleaned with alcohol and then dried using a vacuum dryer. A picosecond laser was used to ablate a honeycomb micropore array structure on the surface of the alloy sheet under an argon atmosphere using grating scanning. The wavelength of the picosecond laser was 10–64 nm, the power was 10–20 W, and the repetition frequency was 50 kHz. The pore size of the micropores was 10–20 μm, and the spacing between adjacent micropores was 100–200 μm. After the picosecond laser processing of the micropore array structure, the zinc alloy substrate was ultrasonically cleaned again with alcohol and then dried using a vacuum dryer. Cerium ammonium nitrate was mixed with citric acid, dissolved in deionized water, and the pH was adjusted to 4-5. The mixture was then heated in a water bath at 80-85℃ to form a transparent sol, thus preparing cerium oxide sol. Pyrrole monomer was added to the cerium oxide sol, and ammonium persulfate solution was added dropwise as an oxidant. The mixture was stirred at room temperature for 6-12 hours to polymerize the polypyrrole composite. Finally, the composite sol was coated onto the surface of the zinc alloy substrate by dip-coating or spin-coating. The zinc alloy substrate was placed in a vacuum resistance furnace and heated to 80-120°C for 1 hour to form a polypyrrole cerium oxide composite film on the surface of the zinc alloy substrate. The zinc alloy substrate is made from the following raw materials in the following mass percentages: aluminum 0.05-0.12%, manganese 0.1-0.3%, copper 0.8-1.5%, titanium 0.01-0.1%, rhenium 0.01-0.05%, with the balance being zinc.

2. A method for preparing the zinc alloy as described in claim 1, characterized in that, Includes the following steps: S1. Smelting and Casting Prepare zinc ingots with a purity of 99.99%, aluminum ingots with a purity of 99.99%, copper granules with a purity of 99.99%, titanium granules with a purity of 99.9%, manganese powder with a purity of 99.9%, and rhenium powder with a purity of 99.99%; before smelting, clean the impurities and oxides from the surface of each raw material. According to the formula, zinc ingots, aluminum ingots, copper granules, titanium granules, manganese powder, and rhenium powder are placed in a vacuum induction furnace under argon protection and heated until the raw materials are completely melted and uniformly mixed. The melt is then kept at 450-500℃ for 60 minutes. A refining agent is added to the melt for refining. The amount of refining agent added is 0.1-0.3% of the mass of the mixed melt. The refining time is 15-20 minutes. The refining process is always carried out under an argon atmosphere to remove surface scum and degas the liquid. The refined liquid is then poured into a preheated graphite mold and cooled in air to obtain an alloy ingot. S2, rapid plastic deformation The alloy ingot was placed in an annealing furnace and held at 280℃ for 6–12 hours for homogenization annealing, and then air-cooled to room temperature. The equal diameter angular extrusion die consists of two interconnected channels with the same cross-section. Molybdenum disulfide is applied to the inner wall of the channel of the extrusion die for lubrication. The extrusion die and the alloy ingot are preheated separately. After preheating, the alloy ingot is placed in the inner channel of the extrusion die. Under the extrusion of the press, the alloy ingot is pressed in through the vertical channel of the extrusion die and pressed out through the horizontal channel of the extrusion die, thus completing the equal diameter angular extrusion. After each extrusion, the alloy ingot is rotated 90° to enter the next pass, with the direction unchanged, and then the next pass of equal diameter angular extrusion is performed. The extrusion process proceeds sequentially from one to six passes; through multiple passes of equal diameter angular extrusion, the grains are refined to the submicron level. Intermediate annealing is performed between multiple passes of equal diameter angular extrusion. During intermediate annealing, the alloy is placed in an annealing furnace and held at 100–250°C for 5–20 minutes, with argon gas purging for protection. After 6 passes of equal diameter angular extrusion, final annealing is performed. During final annealing, the alloy is placed in an annealing furnace and held at 100–250°C for 1–10 minutes. S3, hot rolled The alloy ingot, after rapid plastic deformation, is placed in a vacuum resistance furnace and heated to 150–250°C, held for 60–90 minutes to ensure uniform temperature. The heated ingot is then fed into a two-roll reversible hot rolling mill for hot rolling at a speed of 0.5 m / s, an initial rolling temperature of 220–250°C, and a first pass reduction of 15–20%. Multiple passes are then performed, with subsequent passes gradually reducing the reduction from 15–20% to 10% and increasing the rolling speed to 1.2 m / s, achieving a total deformation of 70–80%. The resulting alloy sheet thickness is 2–4 mm. Argon gas is introduced during the hot rolling process to prevent oxidation. After each hot rolling pass, a fine water mist is sprayed onto the surface of the alloy sheet to cool it to room temperature. Argon gas is introduced for protection during cooling. After the alloy sheet has accumulated 15-20% deformation, intermediate annealing is performed. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 150-200℃ for 30-45 minutes. Argon gas is introduced for protection during intermediate annealing. S4, cold rolled The hot-rolled alloy sheet is pickled in pickling solution and then dried. Then the dried alloy sheet is initially annealed. During the initial annealing, the alloy sheet is placed in an annealing furnace and held at 150-200℃ for 90-120 minutes. Argon gas is introduced for protection during the initial annealing. The alloy sheet after initial annealing is fed into a four-roll cold rolling mill for rolling at a rolling speed of 0.3 m / s. The first pass reduction is 8-10%, and multiple passes of hot rolling are performed in sequence. In subsequent passes, the reduction is gradually reduced from 10% to 8%, and the rolling speed is gradually increased to 0.8 m / s to achieve a total deformation of 50-70%. After cold rolling, the thickness of the zinc alloy substrate is 1-2 mm. After the alloy sheet has accumulated 15-20% deformation, it undergoes intermediate annealing. During intermediate annealing, the alloy sheet is placed in an annealing furnace and held at 150±10℃ for 45-60 minutes, with argon gas protection introduced during the intermediate annealing. After cold rolling, the alloy sheet undergoes final annealing, which is held at 120±10℃ for 45-75 minutes, with argon gas protection introduced during the final annealing. During the cold rolling process, finely atomized nano-lubricant is sprayed onto both sides of the alloy sheet and onto the rolls of the four-roll cold rolling mill. S5, Surface Treatment The cold-rolled zinc alloy substrate was ultrasonically cleaned with alcohol and then dried using a vacuum dryer. A picosecond laser was used to ablate a honeycomb micropore array structure on the surface of the alloy sheet by grating scanning under an argon atmosphere. The wavelength of the picosecond laser was 10–64 nm, the power was 10–20 W, and the repetition frequency was 50 kHz. The pore size of the micropores was 10–20 μm, and the spacing between adjacent micropores was 100–200 μm. After the picosecond laser processed the micropore array structure, the zinc alloy substrate was ultrasonically cleaned again with alcohol and then dried using a vacuum dryer. Cerium ammonium nitrate was mixed with citric acid, dissolved in deionized water, and the pH was adjusted to 4-5. The mixture was then heated in a water bath at 80-85℃ to form a transparent sol, thus preparing cerium oxide sol. Pyrrole monomer was added to the cerium oxide sol, and ammonium persulfate solution was added dropwise as an oxidant. The mixture was stirred at room temperature for 6-12 hours to polymerize the polypyrrole composite. Finally, the composite sol is coated onto the surface of the zinc alloy substrate by dip-coating or spin-coating. The zinc alloy substrate is placed in a vacuum resistance furnace and heated to 80-120°C for 1 hour to form a polypyrrole cerium oxide composite film on the surface of the zinc alloy substrate.

3. The method for preparing a zinc alloy according to claim 2, characterized in that, In step S1, before using the graphite mold, a grinding machine is used to remove surface impurities, and then it is cleaned with deionized water and alcohol in sequence and dried. The graphite mold described in step S1 is preheated at 200°C for 20 minutes.

4. The method for preparing a zinc alloy according to claim 2, characterized in that, The refining agent in step S1 is hexachloroethane.

5. The method for preparing a zinc alloy according to claim 2, characterized in that, In step S2, the inner angle of the extrusion die is 90° and the outer angle is 20°; In step S2, the extrusion die is preheated to 120-200°C and held at 120-200°C for 5-15 minutes; in step S2, the alloy ingot is preheated to 150-250°C.

6. The method for preparing a zinc alloy according to claim 2, characterized in that, In step S4, the pickling solution is sulfuric acid or hydrochloric acid solution, the concentration of the pickling solution is 5% to 10%, the temperature of the pickling solution is 40 to 60°C, and the pickling time is 15 to 20 minutes. The nano-lubricant is a nano-graphite emulsion.