Method for electro-depositing aluminum on brass surface by using ionic liquid

Abstract

The invention relates to the technical field of preparation of metal materials by using ionic liquid, in particular to a method for electro-depositing aluminum on the surface of brass by using ionic liquid, which comprises the following steps of: pretreating the surface of a brass matrix; the method comprises the following steps: drying and melting 1-ethyl-3-methylimidazole chloride ionic liquid, and adding anhydrous aluminum chloride into the molten 1-ethyl-3-methylimidazole chloride to prepare an ionic liquid electrolyte; ionic liquid electrolyte is added into an electrolytic cell, the treated brass is used as a cathode, aluminum is used as an anode, and electro-deposition is carried out under constant current; and the cathode after electro-deposition is taken out, the surface of the electroplated aluminum layer is cleaned and dried, and the aluminum-plated brass is prepared. According to the technical scheme, aluminum trichloride is adopted as anions, 1-ethyl-3-methylimidazole chloride is adopted as cations to form the ionic liquid electrolyte, aluminum electro-deposition is conducted, raw materials are simple and environmentally friendly, operation is convenient, the deposition efficiency of aluminum can be improved, and the corrosion resistance of copper can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of preparing metal materials with ionic liquids, and in particular to a method for electrodepositing aluminum on a brass surface by using ionic liquids. Background Art

[0002] Aluminum is lightweight and its natural oxide has excellent corrosion resistance, so it is often used as a metal coating. The anti-corrosion performance of aluminum coating is based on the formation of a dense passivation layer composed of aluminum oxide, which can prevent further corrosion of the underlying metal. Therefore, the aluminum coating is required to be uniform and crack-free. However, the standard potential of aluminum is relatively negative and cannot be directly electrolyzed from aqueous solution. The currently widely used molecular liquid electrolyte system has inherent disadvantages such as high energy consumption, flammability, volatility and high toxicity. Organic liquid electrolytes have become the best choice for high-temperature, high-pressure, and open electrolyte systems.

[0003] Ionic liquid is a solvent that is completely composed of inorganic anions and organic cations and is liquid at or near room temperature. As a new type of polar solvent, it has almost no vapor pressure, is non-volatile, has good chemical stability and thermal stability, is recyclable and environmentally friendly, so it is called a "green" chemical solvent and can be used to replace traditional toxic solvents. In addition, ionic liquids also have the advantages of wide electrochemical window, good conductivity, good stability, green environmental protection, and reusability. With the continuous improvement of market requirements for aluminum metal applications, the field of electroplating aluminum metal at room temperature has more extensive and in-depth research value.

[0004] Pradhan et al. studied the electrodeposition of aluminum in two ionic liquids, EMIC-AlCl3 and BMIC–AlCl3. The results showed that at 90°C, nodular and uniformly distributed aluminum could be deposited on the copper substrate. More importantly, Kamavaram, Zhang et al. used low-temperature AlCl3-BMIC ionic liquid as an electrolyte to electrolytically refine aluminum alloy (65%~71% Al), and obtained industrial aluminum with a purity of 99% and zero pollutant emissions. The above studies show that the use of ionic liquids as electrolytes can achieve the electrodeposition of aluminum on metal surfaces and the refining of aluminum alloys. Therefore, ionic liquids have gradually become a research hotspot in the field of electrodeposition. In view of this, the method of electrodepositing aluminum on the surface of brass using ionic liquids used in the present invention, AlCl3 is different from most halides in structure, belongs to a covalent compound, and is a strong Lewis acid. Therefore, AlCl3 and other organic substances are easy to form ionic liquids, which is more conducive to the reaction. In order to at least partially solve at least one of the above-mentioned technical problems. Summary of the invention

[0005] The invention aims to provide a method for electrodepositing aluminum on the surface of brass by using ionic liquid. The method adopts aluminum trichloride as anion and 1-ethyl-3-methylimidazolium chloride as cation to form an ionic liquid electrolyte for electrodepositing aluminum. The raw materials are simple and environmentally friendly, the operation is convenient, the deposition efficiency of aluminum can be improved, and the corrosion resistance of copper can be improved.

[0006] To achieve the above object, the present invention provides a method for electrodepositing aluminum on a brass surface using an ionic liquid, comprising the following steps: S1. Pretreatment of brass substrate surface The surface of the brass substrate is subjected to mechanical polishing, cleaning, ultrasonic treatment, and drying in sequence to obtain brass with a clean surface; S2. Preparation of ionic liquid electrolyte The 1-ethyl-3-methylimidazolium chloride ionic liquid is vacuum dried in an inert gas environment and heated to melt, anhydrous aluminum chloride is added to the melted 1-ethyl-3-methylimidazolium chloride to prepare a saturated solution, and the ionic liquid electrolyte is prepared by extraction after cooling; S3, Aluminum electroplating on brass substrate An electrodeposition system is constructed, an ionic liquid electrolyte made of S2 is added to an electrolytic cell equipped with a cathode and an anode, brass treated with S1 is used as a cathode, and aluminum is used as an anode to perform electrodeposition under constant current; S4. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

[0007] Preferably, the mechanical polishing in S1 is to use 1200 mesh SiC sandpaper to polish the surface of the brass substrate, and then polish it with a diamond suspension; the cleaning is to rinse with tap water; the ultrasonication is to ultrasonicate in an acetone solution for 5 minutes; and the drying is to use N2 to dry.

[0008] Preferably, the brass is rinsed with tap water and immersed in 1M HCl solution for 3 minutes before electrodeposition, then rinsed with distilled water, sonicated in acetone for 5 minutes, and finally dried under N2.

[0009] Preferably, the mass fraction ratio of copper to zinc in the brass matrix in S1 is 63:37, and the diameter of the brass matrix is ​​12 mm.

[0010] The biggest disadvantage of AlCl3 ionic liquids is their strong hygroscopicity. When ionic liquids are exposed to air or water, the moisture absorbed from the air will have a great impact on the microstructure and physical and chemical properties of the ionic liquids. Vacuum drying of AlCl3 ionic liquids is beneficial to isolate water and air to the greatest extent, reducing the loss of ionic liquids during electrodeposition.

[0011] Preferably, the vacuum drying pressure in S2 is 0.1 MPa, the vacuum drying temperature is 60-70° C., the vacuum drying time is 12-24 h, and the melting temperature is 77-80° C.

[0012] In AlCl3 type ionic liquids, the molar ratio of AlCl3 to organic salt can adjust the Lewis acidity of the system. The AlCl3 mole fraction of acidic ionic liquids is usually greater than 50%, while that of alkaline ionic liquids is usually less than 50%. - The reduction potential of organic cations is higher than that of AlCl4 - The reduction potential of AlCl4 is corrected, so in this case AlCl4 - The reduction reaction of the electrodeposition cannot produce metallic aluminum. Therefore, the use of an acidic ionic liquid with a molar ratio of 4:6 can enable the electrodeposition reaction to proceed smoothly without causing waste.

[0013] Preferably, the molar ratio of 1-ethyl-3-methylimidazole chloride to anhydrous aluminum chloride in S2 is 4:6.

[0014] Preferably, the extractant used for extraction in S2 includes one or more of ether, toluene and tetrahydrofuran.

[0015] Preferably, the distance between the anode and cathode in S3 is 1 cm, and the surface area ratio of the cathode and cathode is 0.125-0.25. AlCl3 ionic liquid has strong hygroscopicity, and exposure to air will have a great impact on its microstructure and physicochemical properties. The experimental process generally needs to be carried out in a glove box with an inert gas atmosphere. Therefore, the electrodeposition process is carried out in a glove box filled with nitrogen. When the surface area ratio of the cathode and cathode is controlled between 0.125-0.25, the anode dissolves normally and does not passivate. In order to maintain the acidic environment of the system, the cation concentration in the solution is almost unchanged, so that the reaction proceeds normally.

[0016] Preferably, the temperature of the electrodeposition system in S3 is 20-60° C. When the current density is lower than 10 mA / cm 2 When the initial nucleation occurs only at a limited number of points, the nucleation rate is relatively low, and large particles are easily formed. 2 Due to the high overpotential under current density, initial nucleation can be formed at more points, rather than continuing to grow at limited nucleation points, forming a suitable particle size, which is conducive to observing the morphological characteristics of electrodeposited aluminum. Therefore, the current density of the electrodeposition reaction is limited to 10~15 mA / cm 2, the electrodeposition reaction time is 2h. Studies have found that when the electrodeposition temperature is higher than 60℃, ILs will degrade rapidly. This hinders their use in industry and applications. Therefore, the maximum temperature is considered to be more suitable at 60℃.

[0017] Preferably, the mixing conditions for the electrodeposition reaction in S3 are a quiet bath, mechanical stirring or ultrasound.

[0018] More preferably, the speed of mechanical stirring is 320 r / min, and the ultrasonic time is 1 to 10 min.

[0019] Preferably, the cleaning in S4 is first rinsing with deionized water and then cleaning with anhydrous ethanol; and the drying is vacuum drying.

[0020] Mechanism of the Invention Imidazole is an important component of the ionic liquid with 1-ethyl-3-methylimidazolium chloride as the cation, and has a unique electronic and spatial structure.

[0021] The nitrogen atom on the imidazole ring and the hydrogen atom on the adjacent carbon atom can form a hydrogen bond, which makes the imidazole cation have good thermal and chemical stability. When the molar fraction of aluminum chloride anion is excessive, the system begins to produce a large amount of Al2Cl7 - . Due to the significant electron deficiency of Al(III), ionic liquids exhibit certain Lewis acidity and strong reducing properties. At this time, the spatial structural symmetry of anions and cations is enhanced, the volume gap is reduced, and the van der Waals interaction is weakened, which improves the conductivity of the system and reduces the melting point and viscosity of the system.

[0022] In summary, this type of ionic liquid has a good promoting effect on the electrodeposition of metallic aluminum. Beneficial effects of the present invention: (1) The present invention studies the effects of temperature and mixing conditions on the electrodeposition of Al by ionic liquid (BMIM) Cl / AlCl3 (40 / 60 mol %), determines the optimal operating conditions for the industrial aluminum plating process, obtains high-quality aluminum with uniform coating, improves the aluminum deposition efficiency, and improves the corrosion resistance of copper; (2) The process of the present invention is simple, has low requirements on equipment materials, low energy consumption and low cost.

[0023] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of different area ratios of anode and cathode electrodes used in the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The above-mentioned features or features mentioned in the specific examples mentioned in the present invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0026] The brass used in the cathode electrode of the present invention is pretreated by the following method: first, the surface of the brass substrate is polished with 1200 mesh SiC sandpaper, then polished with diamond suspension, rinsed with tap water, ultrasonicated in acetone for 5 minutes, and blown dry with N2 to obtain a brass with a clean surface. Before electrodeposition, it is rinsed with tap water again and immersed in 1M HCl for 3 minutes, rinsed with distilled water, ultrasonicated in acetone for 5 minutes, and then dried under N2.

[0027] Example 1 The present invention provides a method for electrodepositing aluminum on a brass surface using an ionic liquid, comprising the following steps: S1. Preparation of ionic liquid electrolyte First, 1-ethyl-3-methylimidazole chloride is dried with nitrogen at a pressure of 0.1 MPa and a temperature of 60°C for 12 hours. After drying, it is heated to 80°C to melt. Anhydrous aluminum chloride is added to the molten 1-ethyl-3-methylimidazole chloride in a molar ratio of 4:6 between 1-ethyl-3-methylimidazole chloride and aluminum trichloride until the solid phase is completely dissolved into a liquid phase to prepare a saturated solution. After cooling, it is extracted with ether to prepare an ionic liquid electrolyte.

[0028] S2, Aluminum electroplating on brass substrate An electrodeposition system was constructed by adding an ionic liquid electrolyte made of S1 into an electrolytic cell equipped with a cathode and an anode. Brass treated with S1 was used as the cathode and a pure aluminum sheet was used as the anode, fixed in the electrolyte. The area ratio of the anode and cathode electrodes was 0.125 and the distance between the anode and cathode electrodes was 1 cm to form an electrodeposition system.

[0029] The electrodeposition system maintains a constant current and performs an electrodeposition reaction in the electrolyte. The temperature of the electrodeposition system is controlled by a constant temperature water bath. When the temperature of the electrolyte is 20°C, the mixing parameters are a mechanical stirring speed of 320r / min, and an applied constant current of 10mA / cm 2 Under the conditions of , electrodeposition was carried out in the electrolyte for 2h.

[0030] S3. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

[0031] The yield of aluminum electrodeposited in this embodiment is 82%, and the aluminum film on the surface of the obtained copper-based composite material is relatively rough. However, compared with the untreated copper-based composite material, its corrosion resistance is significantly improved, and the corrosion current density is reduced by 100 orders of magnitude.

[0032] Example 2 The present invention provides a method for electrodepositing aluminum on a brass surface using an ionic liquid, comprising the following steps: S1. Preparation of ionic liquid electrolyte First, 1-ethyl-3-methylimidazole chloride is dried with nitrogen at a pressure of 0.1 MPa and a temperature of 60° C. for 12 hours, and then heated to 80° C. to melt. Anhydrous aluminum chloride is added to the molten 1-ethyl-3-methylimidazole chloride in a molar ratio of 4:6 between 1-ethyl-3-methylimidazole chloride and aluminum trichloride until the solid phase is completely dissolved into a liquid phase to prepare a saturated solution, and then cooled and extracted with ether to prepare an ionic liquid electrolyte; S2, Aluminum electroplating on brass substrate An electrodeposition system was constructed by adding an ionic liquid electrolyte made of S1 into an electrolytic cell equipped with a cathode and an anode. Brass treated with S1 was used as the cathode and a pure aluminum sheet was used as the anode, fixed in the electrolyte. The area ratio of the anode and cathode electrodes was 0.25 and the distance between the anode and cathode electrodes was 1 cm to form an electrodeposition system.

[0033] The electrodeposition system maintains a constant current and performs an electrodeposition reaction in the electrolyte. The temperature of the electrodeposition system is controlled by a constant temperature water bath. When the temperature of the electrolyte is 40°C, the mixing parameters are a mechanical stirring speed of 320r / min, and the applied constant current is 15mA / cm 2 Under the conditions of , electrodeposition was carried out in the electrolyte for 2h.

[0034] S3. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

[0035] The yield of aluminum electrodeposited in this embodiment is 100%. The aluminum film on the surface of the obtained copper-based composite material is smooth, uniform and dense. Compared with the untreated copper-based composite material, its corrosion resistance is significantly improved, and the corrosion current density is reduced by 10 6 Orders of magnitude.

[0036] Example 3 The present invention provides a method for electrodepositing aluminum on a brass surface using an ionic liquid, comprising the following steps: S1. Preparation of ionic liquid electrolyte First, 1-ethyl-3-methylimidazole chloride is dried with nitrogen at a pressure of 0.1 MPa and a temperature of 65°C for 12 hours. After drying, it is heated to 79°C to melt. Anhydrous aluminum chloride is added to the molten 1-ethyl-3-methylimidazole chloride in a molar ratio of 4:6 between 1-ethyl-3-methylimidazole chloride and aluminum trichloride until the solid phase is completely dissolved into a liquid phase to prepare a saturated solution. After cooling, it is extracted with ether to prepare an ionic liquid electrolyte.

[0037] S2, Aluminum electroplating on brass substrate An electrodeposition system was constructed by adding an ionic liquid electrolyte made of S1 into an electrolytic cell equipped with a cathode and an anode. Brass treated with S1 was used as the cathode and a pure aluminum sheet was used as the anode, fixed in the electrolyte. The area ratio of the anode and cathode electrodes was 0.125 and the distance between the anode and cathode electrodes was 1 cm to form an electrodeposition system.

[0038] The electrodeposition system maintains a constant current and performs an electrodeposition reaction in the electrolyte. The temperature of the electrodeposition system is controlled by a constant temperature water bath. When the temperature of the electrolyte is 60°C, the mixing parameters are a mechanical stirring speed of 320r / min, and the applied constant current is 10mA / cm 2 Under the conditions of , electrodeposition was carried out in the electrolyte for 2h.

[0039] S3. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

[0040] The yield of aluminum electrodeposited in this embodiment is 100%. The aluminum film on the surface of the obtained copper-based composite material is smooth, uniform and dense. Compared with the untreated copper-based composite material, its corrosion resistance is significantly improved, and the corrosion current density is reduced by 10 5 Orders of magnitude.

[0041] Example 4 The present invention provides a method for electrodepositing aluminum on a brass surface using an ionic liquid, comprising the following steps: S1. Preparation of ionic liquid electrolyte First, 1-ethyl-3-methylimidazole chloride is dried with nitrogen at a pressure of 0.1 MPa and a temperature of 60°C for 12 hours. After drying, it is heated to 80°C to melt. Anhydrous aluminum chloride is added to the molten 1-ethyl-3-methylimidazole chloride in a molar ratio of 4:6 between 1-ethyl-3-methylimidazole chloride and aluminum trichloride until the solid phase is completely dissolved into a liquid phase to prepare a saturated solution. After cooling, it is extracted with ether to prepare an ionic liquid electrolyte.

[0042] S2, Aluminum electroplating on brass substrate An electrodeposition system was constructed by adding an ionic liquid electrolyte made of S1 into an electrolytic cell equipped with a cathode and an anode. Brass treated with S1 was used as the cathode and a pure aluminum sheet was used as the anode, fixed in the electrolyte. The area ratio of the anode and cathode electrodes was 0.125 and the distance between the anode and cathode electrodes was 1 cm to form an electrodeposition system.

[0043] The electrodeposition system maintains a constant current and conducts an electrodeposition reaction in the electrolyte. The temperature of the electrodeposition system is controlled by a constant temperature water bath. When the temperature of the electrolyte is 20°C, the mixing parameters are ultrasound for 1 minute, the ultrasound frequency is controlled to be mild, and it is turned on for 1 second every 10 seconds. The constant current applied is 10mA / cm 2 Under the conditions of , electrodeposition was carried out in the electrolyte for 2h.

[0044] S3. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

[0045] The yield of aluminum electrodeposited in this embodiment is 100%. The aluminum film on the surface of the obtained copper-based composite material is relatively rough, but compared with the untreated copper-based composite material, its corrosion resistance is significantly improved, and the corrosion current density is reduced by 10 3 Orders of magnitude.

[0046] Example 5 The present invention provides a method for electrodepositing aluminum on a brass surface using an ionic liquid, comprising the following steps: S1. Preparation of ionic liquid electrolyte First, 1-ethyl-3-methylimidazole chloride is dried with nitrogen at a pressure of 0.1 MPa and a temperature of 70°C for 12 hours. After drying, it is heated to 80°C to melt. Anhydrous aluminum chloride is added to the molten 1-ethyl-3-methylimidazole chloride in a molar ratio of 4:6 between 1-ethyl-3-methylimidazole chloride and aluminum trichloride until the solid phase is completely dissolved into a liquid phase to prepare a saturated solution. After cooling, it is extracted with ether to prepare an ionic liquid electrolyte.

[0047] S2, Aluminum electroplating on brass substrate An electrodeposition system was constructed by adding an ionic liquid electrolyte made of S1 into an electrolytic cell equipped with a cathode and an anode. Brass treated with S1 was used as the cathode and a pure aluminum sheet was used as the anode, fixed in the electrolyte. The area ratio of the anode and cathode electrodes was 0.25 and the distance between the anode and cathode electrodes was 1 cm to form an electrodeposition system.

[0048] The electrodeposition system maintains a constant current and conducts an electrodeposition reaction in the electrolyte. The temperature of the electrodeposition system is controlled by a constant temperature water bath. When the temperature of the electrolyte is 40°C, the mixing parameter is ultrasound for 10 minutes, the ultrasound frequency is controlled to be slightly turned on for 1 second every 10 seconds, and the constant current applied is 15mA / cm 2 Under the conditions of , electrodeposition was carried out in the electrolyte for 2h.

[0049] S3. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

[0050] The yield of aluminum electrodeposited in this embodiment is 100%. The aluminum film on the surface of the obtained copper-based composite material is smooth, uniform and dense. Compared with the untreated copper-based composite material, its corrosion resistance is significantly improved, and the corrosion current density is reduced by 10 6 Orders of magnitude.

[0051] Example 6 The present invention provides a method for electrodepositing aluminum on a brass surface using an ionic liquid, comprising the following steps: S1. Preparation of ionic liquid electrolyte First, 1-ethyl-3-methylimidazole chloride is dried with nitrogen at a pressure of 0.1 MPa and a temperature of 70°C for 24 hours. After drying, it is heated to 80°C to melt. Anhydrous aluminum chloride is added to the molten 1-ethyl-3-methylimidazole chloride in a molar ratio of 4:6 between 1-ethyl-3-methylimidazole chloride and aluminum trichloride until the solid phase is completely dissolved into a liquid phase to prepare a saturated solution. After cooling, it is extracted with ether to prepare an ionic liquid electrolyte.

[0052] S2, Aluminum electroplating on brass substrate An electrodeposition system was constructed by adding an ionic liquid electrolyte made of S1 into an electrolytic cell equipped with a cathode and an anode. Brass treated with S1 was used as the cathode and a pure aluminum sheet was used as the anode, fixed in the electrolyte. The area ratio of the anode and cathode electrodes was 0.125 and the distance between the anode and cathode electrodes was 1 cm to form an electrodeposition system.

[0053] The electrodeposition system maintains a constant current and conducts an electrodeposition reaction in the electrolyte. The temperature of the electrodeposition system is controlled by a constant temperature water bath. When the temperature of the electrolyte is 60°C, the mixing parameter is ultrasound for 10 minutes, the ultrasound frequency is controlled to be slightly closed for 10 seconds and opened for 1 second, and the constant current applied is 10mA / cm 2 Under the conditions of , electrodeposition was carried out in the electrolyte for 2h.

[0054] S3. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

[0055] The yield of aluminum electrodeposited in this embodiment is 100%. The aluminum film on the surface of the obtained copper-based composite material is smooth, uniform and dense. Compared with the untreated copper-based composite material, its corrosion resistance is significantly improved, and the corrosion current density is reduced by 10 5 Orders of magnitude.

[0056] Example 7 The present invention provides a method for electrodepositing aluminum on a brass surface using an ionic liquid, comprising the following steps: S1. Preparation of ionic liquid electrolyte First, 1-ethyl-3-methylimidazole chloride is dried with nitrogen at a pressure of 0.1 MPa and a temperature of 70°C for 24 hours. After drying, it is heated to 80°C to melt. Anhydrous aluminum chloride is added to the molten 1-ethyl-3-methylimidazole chloride in a molar ratio of 4:6 between 1-ethyl-3-methylimidazole chloride and aluminum trichloride until the solid phase is completely dissolved into a liquid phase to prepare a saturated solution. After cooling, it is extracted with ether to prepare an ionic liquid electrolyte.

[0057] S2, Aluminum electroplating on brass substrate An electrodeposition system was constructed by adding an ionic liquid electrolyte made of S1 into an electrolytic cell equipped with a cathode and an anode. Brass treated with S1 was used as the cathode and a pure aluminum sheet was used as the anode, fixed in the electrolyte. The area ratio of the anode and cathode electrodes was 0.125 and the distance between the anode and cathode electrodes was 1 cm to form an electrodeposition system.

[0058] The electrodeposition system maintains a constant current and performs electrodeposition reaction in the electrolyte. The temperature of the electrodeposition system is controlled by a constant temperature water bath. When the temperature of the electrolyte is 40°C, the mixing parameter is a quiet bath, and the constant current applied is 10mA / cm 2 Under the conditions of , electrodeposition was carried out in the electrolyte for 2h.

[0059] S3. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

[0060] The yield of aluminum electrodeposited in this embodiment is 45%. The aluminum film on the surface of the obtained copper-based composite material is smooth, uniform and dense. Compared with the untreated copper-based composite material, its corrosion resistance is significantly improved, and the corrosion current density is reduced by 10 4 Orders of magnitude.

[0061] Example 8 The present invention provides a method for electrodepositing aluminum on a brass surface using an ionic liquid, comprising the following steps: S1. Preparation of ionic liquid electrolyte First, 1-ethyl-3-methylimidazole chloride is dried with nitrogen at a pressure of 0.1 MPa and a temperature of 70°C for 12 hours. After drying, it is heated to 77°C to melt. Anhydrous aluminum chloride is added to the molten 1-ethyl-3-methylimidazole chloride in a molar ratio of 4:6 between 1-ethyl-3-methylimidazole chloride and aluminum trichloride until the solid phase is completely dissolved into a liquid phase to prepare a saturated solution. After cooling, it is extracted with ether to prepare an ionic liquid electrolyte.

[0062] S2, Aluminum electroplating on brass substrate An electrodeposition system was constructed by adding an ionic liquid electrolyte made of S1 into an electrolytic cell equipped with a cathode and an anode. Brass treated with S1 was used as the cathode and a pure aluminum sheet was used as the anode, fixed in the electrolyte. The area ratio of the anode and cathode electrodes was 0.25 and the distance between the anode and cathode electrodes was 1 cm to form an electrodeposition system.

[0063] The electrodeposition system maintains a constant current and conducts an electrodeposition reaction in the electrolyte. The temperature of the electrodeposition system is controlled by a constant temperature water bath. When the temperature of the electrolyte is 60°C, the mixing parameter is a quiet bath, and the constant current applied is 10mA / cm 2 Under the conditions of , electrodeposition was carried out in the electrolyte for 2h.

[0064] S3. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

[0065] The yield of aluminum electrodeposited in this embodiment is 69%. The aluminum film on the surface of the obtained copper-based composite material is smooth, uniform and dense. Compared with the untreated copper-based composite material, its corrosion resistance is significantly improved, and the corrosion current density is reduced by 10 4 Orders of magnitude.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for electrodepositing aluminum on a brass surface using an ionic liquid, characterized in that: The following steps are involved: S1. Pretreatment of brass substrate surface The surface of the brass substrate is subjected to mechanical polishing, cleaning, ultrasonic treatment, and drying in sequence to obtain brass with a clean surface; S2. Preparation of ionic liquid electrolyte The 1-ethyl-3-methylimidazolium chloride ionic liquid is vacuum dried in an inert gas environment and heated to melt, anhydrous aluminum chloride is added to the melted 1-ethyl-3-methylimidazolium chloride to prepare a saturated solution, and the ionic liquid electrolyte is prepared by extraction after cooling; S3, Aluminum electroplating on brass substrate An electrodeposition system is constructed, an ionic liquid electrolyte made of S2 is added to an electrolytic cell equipped with a cathode and an anode, brass treated with S1 is used as a cathode, and aluminum is used as an anode to perform electrodeposition under constant current; S4. Treatment of brass substrate surface after electrodeposition The cathode after electrodeposition in step S3 is taken out, and the surface of the electroplated aluminum layer is cleaned and dried to obtain aluminum-plated brass.

2. A method for electrodepositing aluminum on a brass surface using ionic liquid according to claim 1, characterized in that: In S1, mechanical grinding is to use 1200 mesh SiC sandpaper to grind the surface of the brass substrate, and then polish it with diamond suspension; cleaning is to rinse with tap water; ultrasonication is to ultrasonicate in acetone solution for 5 minutes; and drying is to use N2 to dry.

3. The method for electrodepositing aluminum on a brass surface using an ionic liquid according to claim 1, characterized in that: The mass fraction ratio of copper to zinc in the brass matrix of S1 is 63:37, and the diameter of the brass matrix is ​​12 mm.

4. The method for electrodepositing aluminum on a brass surface using an ionic liquid according to claim 1, characterized in that: The vacuum drying pressure in S2 is 0.1 MPa, the vacuum drying temperature is 60-70°C, the vacuum drying time is 12-24h, and the melting temperature is 77-80°C.

5. The method for electrodepositing aluminum on a brass surface using ionic liquid according to claim 1, characterized in that: The molar ratio of 1-ethyl-3-methylimidazole chloride to anhydrous aluminum chloride in S2 is 4:

6.

6. The method for electrodepositing aluminum on a brass surface using ionic liquid according to claim 1, characterized in that: The extractant used for extraction in S2 includes one or more of ether, toluene and tetrahydrofuran.

7. The method for electrodepositing aluminum on a brass surface using an ionic liquid according to claim 1, characterized in that: In S3, the distance between the anode and cathode is 1 cm, the surface area ratio of the cathode and cathode is 0.125~0.25, and the electrodeposition process is carried out in a glove box filled with nitrogen.

8. The method for electrodepositing aluminum on a brass surface using ionic liquid according to claim 1, characterized in that: The temperature of the electrodeposition system in S3 is 20~60℃, and the current density of the electrodeposition reaction is 10~15 mA / cm 2 , the electrodeposition reaction time is 2h.

9. The method for electrodepositing aluminum on a brass surface using ionic liquid according to claim 1, characterized in that: The mixing conditions for the electrodeposition reaction in S3 are a quiet bath, mechanical stirring or ultrasound.

10. The method for electrodepositing aluminum on a brass surface using ionic liquid according to claim 1, characterized in that: The cleaning in S4 is first rinsing with deionized water and then cleaning with anhydrous ethanol; the drying is vacuum drying.

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