Preparation method of Al-Ti alloy coating through ionic liquid electro-deposition at room temperature

Abstract

The invention provides a preparation method of an A < l >-T alloy coating through ionic liquid electro-deposition at room temperature, and relates to the technical field of metal surface protection. The preparation method of the Al-Ti alloy plating layer through ionic liquid electro-deposition at the room temperature comprises the following specific steps that S1, ionic liquid preparation is conducted, specifically, the ionic liquid composed of organic matter, aluminum salt, fluoride of the aluminum salt and titanium salt serves as electrolyte, hydroboron and fluorine complex of the hydroboron serve as reducing agents, and full mixing is conducted for standby application; s2, electro-deposition matrix cleaning: polishing, epoxy resin packaging and curing, secondary polishing, ultrasonic cleaning and sealing and storage with a metallographic adhesive tape; and S3, preparing the A < l >-T alloy, wherein the ionic liquid prepared in the step S1 serves as electrolyte. By controlling the electro-deposition conditions, the Al-Ti alloy coating which is uniform and compact and has the titanium content of 10-50% can be prepared, and the corrosion resistance of the Al-Ti alloy coating is improved. The ionic liquid used in the method is environmentally friendly and easy to operate, and the plating layer with high titanium content and controllable plating layer thickness can be obtained in the room temperature environment.

Description

Technical Field

[0001] The invention relates to the technical field of metal surface protection, in particular to a method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature. Background Art

[0002] Aluminum-titanium alloys occupy an important position in the current industry due to their excellent specific strength, high temperature resistance and corrosion resistance. As key materials in the fields of aerospace, automobile manufacturing and high-temperature equipment, aluminum-titanium alloys not only promote technological innovation, but also provide reliable guarantees for high-performance applications. Methods for preparing Al-Ti alloys include sputtering deposition, vapor deposition and electrodeposition. Since the standard electrode potential of aluminum is -1.66Vvs.SHE, aluminum is relatively active in electrodeposition. Therefore, when Al-Ti alloys are electrodeposited in aqueous electrolytes, they will fail due to hydrogen evolution reaction. The method of electrodeposition / electrolytic refining of titanium and its alloys from high-temperature chloride / fluoride melts has been widely studied. Although feasible, the problems of high temperature, high energy consumption and strong corrosion limit its application.

[0003] As a new type of polar solvent, ionic liquids (ILs) offer virtually no vapor pressure, excellent solubility, good chemical and thermal stability, designability, recyclability, and environmental friendliness. They are therefore known as "green" solvents, potentially replacing traditional volatile and toxic solvents. Ionic liquid systems exhibit excellent electrical conductivity and a wide electrochemical window, making them ideal media for metal electrodeposition. However, limited research has been conducted on the electrodeposition of Al-Ti alloys using these systems and their corrosion resistance.

[0004] To this end, we have developed a new method for preparing Al-Ti alloy coatings by ionic liquid electrodeposition at room temperature. Summary of the Invention

[0005] (1) Technical problems solved

[0006] In response to the shortcomings of the existing technology, the present invention provides a method for preparing an aluminum-titanium alloy coating by ionic liquid electrodeposition at room temperature. By controlling the electrodeposition conditions, this method can prepare a uniform and dense Al-Ti alloy coating with a titanium content of 10-50%, and improve the corrosion resistance of the Al-Ti coating.

[0007] (2) Technical solution

[0008] To achieve the above objectives, the present invention is implemented by the following technical solution: a method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature, comprising the following specific steps:

[0009] S1. Preparation of ionic liquid: an ionic liquid composed of organic matter, aluminum salt and its fluoride, and titanium salt is used as an electrolyte, and a borohydride and its fluoride ligand is used as a reducing agent, and the mixture is thoroughly mixed for later use;

[0010] S2. Cleaning the electrodeposited substrate: polishing - epoxy resin encapsulation and curing - polishing again - ultrasonic cleaning - sealing with metallographic tape;

[0011] S3. Preparation of Al-Ti alloy: Using the ionic liquid prepared in S1 as the electrolyte, electrodeposition is performed using a constant current. During the electrodeposition process, the electrodeposition substrate cleaned in S2 is used as the working electrode, the titanium sheet is used as the auxiliary electrode, and the platinum electrode is used as the reference electrode;

[0012] After the electrodeposition, the electrolyte adhered to the surface is cleaned with deionized water and ethanol, and the Al-Ti alloy coating is obtained after drying.

[0013] Preferably, the specific steps for preparing the ionic liquid in S1 are:

[0014] In a sealed glove box filled with nitrogen, the vacuum-dried organic matter and aluminum salt and its fluoride are placed in a reagent bottle in proportion and mixed and dissolved. A magnetic stirrer is used to stir until the aluminum salt and its fluoride are completely dissolved.

[0015] After a light yellow transparent liquid is formed, a borohydride and a fluorine complex thereof are added at a mass ratio of 5% to 20%, and then a reducing agent is added, and the mixture is fully stirred for later use.

[0016] Preferably, the organic matter is any one of 1-ethyl-3-methylimidazole chloride, 1-ethylpyridine chloride, triethylammonium chloride, 1-butyl-3-methylimidazole chloride, 1-butylpyridine chloride, trimethylammonium chloride and the like; the anhydrous aluminum salt and its fluoride are anhydrous AlCl3 and its fluoride; the titanium salt is K2TiF6; and the borohydride and its fluoride ligand are a mixture of sodium borohydride, sodium tris(trifluoroacetyl)borohydride, and sodium cyanoborohydride.

[0017] Preferably, the vacuum drying temperature is 30-80° C. and the time is 12-24 hours.

[0018] Preferably, the molar ratio of the anhydrous AlCl3 and its fluoride to the organic matter is 10:1-1:1.

[0019] Preferably, the specific steps of cleaning the electrodeposition substrate in S2 are:

[0020] The electrodeposited substrate is polished with sandpaper to remove surface rust;

[0021] The back of the substrate is connected with a wire and encapsulated with epoxy resin and cured for 12-96 hours;

[0022] The cured electrode is sanded and polished in sequence until the surface has a mirror effect;

[0023] Finally, the electrodes were rinsed with ethanol and then ultrasonically cleaned, and sealed with metallographic tape for later use.

[0024] Preferably, the electrodeposition substrate is any one of stainless steel, copper, low carbon steel, and magnesium alloy, and the sandpaper specifications are 400#, 800#, 1000#, 1500#, and 2000#.

[0025] Preferably, the electrodeposition time in step S3 is 0.5-6 hours.

[0026] Preferably, the constant current is 3-60 mA / cm2.

[0027] Preferably, the effective area of the working electrode in S3 is 1 cm2, the effective area of the auxiliary electrode is 2 cm2, and the distance between the two electrodes is 10-15 mm.

[0028] (3) Beneficial effects

[0029] The present invention provides a method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature. It has the following beneficial effects:

[0030] By controlling the electrodeposition conditions, the present invention can produce a uniform and dense Al-Ti alloy coating with a titanium content of 10-50%, while also improving the corrosion resistance of the Al-Ti coating. The ionic liquid used in the present invention is environmentally friendly and easy to operate, and can produce a coating with a high titanium content and controllable coating thickness at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] S1. Preparation of ionic liquid: an ionic liquid composed of organic matter, aluminum salt and its fluoride and titanium salt is used as electrolyte, and borohydride and its fluoride ligand is used as reducing agent, and the mixture is fully mixed for later use.

[0034] Specific steps for preparing the ionic liquid in S1:

[0035] In a sealed glove box filled with nitrogen, the vacuum-dried organic matter and aluminum salt and its fluoride are placed in a reagent bottle in proportion and mixed and dissolved. A magnetic stirrer is used to stir until the aluminum salt and its fluoride are completely dissolved.

[0036] After a light yellow transparent liquid is formed, a borohydride and a fluorine complex thereof are added at a mass ratio of 5% to 20%, and then a reducing agent is added, and the mixture is fully stirred for later use.

[0037] The organic matter is any one of 1-ethyl-3-methylimidazole chloride, 1-ethylpyridinium chloride, triethylammonium chloride, 1-butyl-3-methylimidazole chloride, 1-butylpyridinium chloride, trimethylammonium chloride and the like; the aluminum salt and its fluoride are anhydrous AlCl3 and its fluoride; the titanium salt is K2TiF6; and the borohydride and its fluoride ligand are a mixture of sodium borohydride, sodium tris(trifluoroacetyl)borohydride, and sodium cyanoborohydride.

[0038] The vacuum drying temperature is 30-80°C and the time is 12-24h.

[0039] The molar ratio of anhydrous AlCl 3 and its fluoride to organic matter is 10:1-1:1.

[0040] S2. Cleaning the electrodeposited substrate: polishing - epoxy resin encapsulation and curing - polishing again - ultrasonic cleaning - sealing with metallographic tape;

[0041] Specific steps for cleaning the electrodeposition substrate in S2:

[0042] The electrodeposited substrate is polished with sandpaper to remove surface rust;

[0043] The back of the substrate is connected with a wire and encapsulated with epoxy resin and cured for 12-96 hours;

[0044] The cured electrode is sanded and polished in sequence until the surface has a mirror effect;

[0045] Finally, the electrodes were rinsed with ethanol and then ultrasonically cleaned, and sealed with metallographic tape for later use.

[0046] The electrodeposition substrate is any one of stainless steel, copper, low carbon steel, and magnesium alloy, and the sandpaper specifications are 400#, 800#, 1000#, 1500#, and 2000#.

[0047] S3. Preparation of Al-Ti alloy: Using the ionic liquid prepared in S1 as the electrolyte, electrodeposition is performed using a constant current. During the electrodeposition process, the electrodeposition substrate cleaned in S2 is used as the working electrode, the titanium sheet is used as the auxiliary electrode, and the platinum electrode is used as the reference electrode;

[0048] After the electrodeposition, the electrolyte adhered to the surface is cleaned with deionized water and ethanol, and the Al-Ti alloy coating is obtained after drying.

[0049] The electrodeposition time in step S3 is 0.5-6 hours.

[0050] The constant current is 3-60mA / cm2.

[0051] The effective area of the working electrode in S3 is 1 cm2, the effective area of the auxiliary electrode is 2 cm2, and the distance between the two electrodes is 10-15 mm.

[0052] Example 1:

[0053] At room temperature, AlCl₃ and 1-ethyl-3-methylimidazolium chloride were mixed in a 2:1 molar ratio to form an ionic liquid. K₂TiF₆ (10% by weight) and an appropriate amount of sodium borohydride were added and stirred until dissolved. Using a three-electrode system, a Cu substrate was polished with 400#, 800#, 1000#, 1500#, and 2000# sandpaper, followed by ultrasonic cleaning with deionized water and anhydrous ethanol for 5 minutes, respectively. Electrodeposition was performed at a current of 10 mA for 60 minutes, resulting in an Al-Ti alloy coating with an average thickness of approximately 14.31 μm and a titanium content of 16.31 wt%.

[0054] Example 2:

[0055] At room temperature, AlCl3 and 1-ethyl-3-methylimidazole chloride (hereinafter referred to as EMIC) are mixed in a molar ratio of 2:1 to form an ionic liquid, and K2TiF6 with a mass ratio of 10% and an appropriate amount of sodium borohydride are added and stirred until dissolved. A three-electrode system is used, with Cu as the substrate. After polishing with 400#, 800#, 1000#, 1500#, and 2000# sandpaper, it is ultrasonically cleaned with deionized water and anhydrous ethanol for 5 minutes respectively. The electrodeposition current is adjusted to 15mA, and the time is also 60min, to obtain an Al-Ti alloy coating with an average thickness of about 32.83μm and a titanium content of 17.55wt%.

[0056] Example 3:

[0057] At room temperature, AlCl₃ and EMIC were mixed in a 2:1 molar ratio to form an ionic liquid. K₂TiF₆ (10% by weight) and an appropriate amount of sodium borohydride were added and stirred until dissolved. Using a three-electrode system, a Cu substrate was polished with 400#, 800#, 1000#, 1500#, and 2000# sandpaper, followed by ultrasonic cleaning with deionized water and anhydrous ethanol for 5 minutes, respectively. The electrodeposition current was adjusted to 20 mA, and the deposition time was 60 minutes, resulting in an Al-Ti alloy coating with an average thickness of approximately 38.22 μm and a higher titanium content of 19.95 wt%.

[0058] Example 4:

[0059] At room temperature, AlCl3 and EMIC were mixed in a molar ratio of 2:1 to form an ionic liquid. K2TiF6 (10% by mass) and an appropriate amount of sodium borohydride were added and stirred until dissolved. A three-electrode system was used with Cu as the substrate. The substrate was polished with 400#, 800#, 1000#, 1500#, and 2000# sandpaper, and then ultrasonically cleaned with deionized water and anhydrous ethanol for 5 minutes, respectively. At an electrodeposition current density of 20 mA / cm2 and varying deposition times (45 min to 120 min), an Al-Ti alloy coating with an average thickness of approximately 29.57 μm was obtained for a deposition time of 45 min, with a titanium content of 17.46 wt%.

[0060] Example 5:

[0061] At room temperature, AlCl₃ and EMIC were mixed in a 2:1 molar ratio to form an ionic liquid. K₂TiF₆ (10% by mass) and an appropriate amount of sodium borohydride were added and stirred until dissolved. Using a three-electrode system, a Cu substrate was polished with 400#, 800#, 1000#, 1500#, and 2000# sandpaper, followed by ultrasonic cleaning with deionized water and anhydrous ethanol for 5 minutes, respectively. At an electrodeposition current density of 20 mA / cm₂ and a deposition time of 60 minutes, an Al-Ti alloy coating with an average thickness of approximately 47.38 μm and a titanium content of 20.34 wt% was obtained.

[0062] Example 6:

[0063] At room temperature, AlCl₃ and EMIC were mixed in a 2:1 molar ratio to form an ionic liquid. K₂TiF₆ (10% by mass) and an appropriate amount of sodium borohydride were added and stirred until dissolved. Using a three-electrode system, a Cu substrate was polished with 400#, 800#, 1000#, 1500#, and 2000# sandpaper, followed by ultrasonic cleaning with deionized water and anhydrous ethanol for 5 minutes, respectively. At an electrodeposition current density of 20 mA / cm₂ and a deposition time of 90 minutes, an Al-Ti alloy coating with an average thickness of approximately 38.03 μm and a titanium content of 18.31 wt% was obtained.

[0064] Example 7:

[0065] At room temperature, AlCl₃ and EMIC were mixed in a 2:1 molar ratio to form an ionic liquid. K₂TiF₆ (10% by weight) and an appropriate amount of sodium borohydride were added and stirred until dissolved. Using a three-electrode system, a Cu substrate was polished with 400#, 800#, 1000#, 1500#, and 2000# sandpaper, followed by ultrasonic cleaning with deionized water and anhydrous ethanol for 5 minutes, respectively. At an electrodeposition current density of 20 mA / cm₂ and a deposition time of 120 minutes, an Al-Ti alloy coating with an average thickness of approximately 18.97 μm and a titanium content of 16.83 wt% was obtained.

[0066] The thickness and titanium content of the Al-Ti alloy coatings obtained in the above-mentioned embodiments are compared, and the results are shown in the following table:

[0067] Example Average thickness of Al-Ti alloy coating (μm) Titanium content (wt%) Example 1 14.31 16.31 Example 2 32.83 17.55 Example 3 38.22 19.95 Example 4 29.57 17.46 Example 5 47.38 20.34 Example 6 38.03 18.31 Example 7 18.97 16.83

[0068] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature, characterized in that: The specific steps include: S1. Preparation of ionic liquid: an ionic liquid composed of organic matter, aluminum salt and its fluoride, and titanium salt is used as an electrolyte, and a borohydride and its fluoride ligand is used as a reducing agent, and the mixture is thoroughly mixed for later use; S2. Cleaning the electrodeposited substrate: polishing - epoxy resin encapsulation and curing - polishing again - ultrasonic cleaning - sealing with metallographic tape; S3. Preparation of Al-Ti alloy: Using the ionic liquid prepared in S1 as the electrolyte, electrodeposition is performed using a constant current. During the electrodeposition process, the electrodeposition substrate cleaned in S2 is used as the working electrode, the titanium sheet is used as the auxiliary electrode, and the platinum electrode is used as the reference electrode; After the electrodeposition, the electrolyte adhered to the surface is cleaned with deionized water and ethanol, and the Al-Ti alloy coating is obtained after drying.

2. The method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature according to claim 1, characterized in that: The specific steps for preparing the ionic liquid in S1 are: In a sealed glove box filled with nitrogen, the vacuum-dried organic matter and aluminum salt and its fluoride are placed in a reagent bottle in proportion and mixed and dissolved. A magnetic stirrer is used to stir until the aluminum salt and its fluoride are completely dissolved. After a light yellow transparent liquid is formed, a borohydride and a fluorine complex thereof are added at a mass ratio of 5% to 20%, and then a reducing agent is added, and the mixture is fully stirred for later use.

3. The method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature according to claim 2, characterized in that: The organic matter is any one of 1-ethyl-3-methylimidazole chloride, 1-ethylpyridine chloride, triethylammonium chloride, 1-butyl-3-methylimidazole chloride, 1-butylpyridine chloride, trimethylammonium chloride, etc.; the aluminum salt and its fluoride are anhydrous AlCl3 and its fluoride; the titanium salt is K2TiF6; and the borohydride and its fluoride ligand are a mixture of sodium borohydride, sodium tris(trifluoroacetyl)borohydride, and sodium cyanoborohydride.

4. The method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature according to claim 3, characterized in that: The vacuum drying temperature is 30-80° C. and the time is 12-24 hours.

5. The method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature according to claim 3, characterized in that: The molar ratio of the anhydrous AlCl3 and its fluoride to the organic matter is 10:1-1:

1.

6. The method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature according to claim 1, characterized in that: The specific steps of cleaning the electrodeposition substrate in S2 are: The electrodeposited substrate is polished with sandpaper to remove surface rust; The back of the substrate is connected with a wire and encapsulated with epoxy resin and cured for 12-96 hours; The cured electrode is sanded and polished in sequence until the surface has a mirror effect; Finally, the electrodes were rinsed with ethanol and then ultrasonically cleaned, and sealed with metallographic tape for later use.

7. The method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature according to claim 6, characterized in that: The electrodeposition substrate is any one of stainless steel, copper, low carbon steel, and magnesium alloy, and the sandpaper specifications are 400#, 800#, 1000#, 1500#, and 2000#.

8. The method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature according to claim 1, characterized in that: The electrodeposition time in step S3 is 0.5-6 hours.

9. The method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature according to claim 1, characterized in that: The constant current is 3-60 mA / cm2.

10. The method for preparing an Al-Ti alloy coating by ionic liquid electrodeposition at room temperature according to claim 1, characterized in that: The effective area of the working electrode in S3 is 1 cm2, the effective area of the auxiliary electrode is 2 cm2, and the distance between the two electrodes is 10-15 mm.

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