A method for electrodepositing gallium-nickel alloys in alkaline solutions

Abstract

The present application relates to a kind of methods for preparing gallium-nickel alloy by electrodeposition in alkaline solution, which first configures the alkaline electrolyte composed of sodium gallate, nickel sulfate and ammonia water, wherein the concentration of gallium ions is 10 g / L-20 g / L, the concentration of nickel ions is 0.2 g / L-1 g / L, and the pH is 10.6-12.3. The working electrode and auxiliary electrode are installed in the electrolytic cell, and constant potential or constant current electrodeposition is carried out using a constant potential instrument or a constant current power supply. By adjusting the potential, current and plating solution concentration, alloy coatings with different gallium-nickel ratios can be prepared on the working electrode. The electrolyte composition of the present application is simple, environmentally friendly and non-polluting, the operation process is simple, no harmful gas is generated during electrodeposition, and gallium-nickel alloy coating can be quickly and efficiently prepared in an open environment at room temperature.

Description

Technical Field

[0001] This invention relates to the field of gallium-nickel alloy electroplating technology, and in particular to a method for preparing gallium-nickel alloys by electrodeposition in an alkaline solution. Background Technology

[0002] Gallium-nickel alloys currently have wide applications in medicine, catalysis, and other fields. In the medical field, gallium-nickel solid targets with a gallium content of 75% can produce [a specific effect] upon irradiation. 68 Ge 68 The product of Ge decay 68 Ga (Ga) can be used in nuclear medicine drugs. Due to the low melting point of gallium, a gallium-nickel alloy with a higher melting point is needed to prevent liquefaction of the target material during irradiation. Gallium-nickel alloys, as catalysts for carbon dioxide reduction, exhibit high catalytic efficiency, high methanol yield, and low carbon monoxide formation, showing broad prospects in the field of photoelectrocatalysis. Felix Studt et al. demonstrated through calculations that gallium-nickel alloy catalysts can catalyze the reduction of carbon dioxide to methanol, and experimentally proved that when the nickel content is 62.5–67.5%, the gallium-nickel alloy catalyst exhibits good activity and stability in the reduction of carbon dioxide at atmospheric pressure, with methanol yield comparable to traditional catalysts but fewer side reactions. In petrochemical production, industrially, catalytic hydrogenation is often used to remove trace amounts of acetylene remaining in ethylene feedstock gas. When used as a catalyst in the selective hydrogenation of acetylene with a Ni / Ga ratio of 5, the gallium-nickel alloy shows higher ethylene selectivity than a single nickel catalyst, with an acetylene conversion rate approaching 100%, and the catalyst exhibits high stability.

[0003] Impregnation-H2 high-temperature reduction is a traditional method for preparing gallium-nickel coatings. Felix Studt et al. impregnated silicon dioxide with a mixed aqueous solution of nickel nitrate and gallium nitrate, and then reduced it in an H2 atmosphere at 700℃ for 2 hours to prepare three nickel-gallium alloy catalysts with different atomic ratios: Ni3Ga, NiGa, and Ni5Ga3. Wang Lei et al. impregnated silicon dioxide with a mixed aqueous solution of nickel nitrate and gallium nitrate, dried it at 120℃ for 12 hours, and calcined it at 500℃ for 4 hours to obtain a catalyst precursor. The precursor was then loaded into a quartz fixed-bed reactor and reduced with H2 at 450℃ for 2 hours to prepare a series of Ni alloys with different atomic ratios. x Ga alloy catalyst (x=10~2). Traditional reduction methods require high-temperature conditions, and the alloy composition is greatly affected by temperature, which limits the control of the gallium-nickel ratio in the alloy.

[0004] Electrodeposition methods for preparing gallium-nickel alloys are not limited by high-temperature conditions and can be divided into two types depending on the type of plating solution: ionic liquids and aqueous solutions. Patent CN 105112962 B discloses a method for preparing nickel-gallium alloys by ionic liquid electrodeposition. Vacuum-dried nickel and gallium salts are added to an imidazole-based ionic liquid solvent, followed by the addition of a solubilizer and a grain refiner. The deposition is maintained at a deposition potential of -1.0 to -2.0 V and a deposition temperature of 40 to 80 °C for 10 to 3600 s, ultimately obtaining a nickel-gallium coating with a gallium mass fraction of 5% to 50%. Gu Xing used 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM]TFO) as the ionic liquid. In a glove box, nickel chloride hexahydrate was placed in the ionic liquid, and the mixture was magnetically stirred at 70°C for 2 hours. Propanol was added as a solubilizer, followed by gallium chloride solution. Electrodeposition was performed at a deposition potential of -1.2 to -2 V and a deposition temperature of 75°C, yielding nickel-gallium alloys with a nickel content of 61.5% to 67.8% and a gallium content of 32.2% to 38.5%. However, ionic liquid electrodeposition methods have limitations, such as complex plating bath composition and high requirements for the protective atmosphere, cleanliness, and vacuum level of the electroplating environment. The stability of AlCl3 ionic liquids is easily affected by acids, alkalis, and moisture in the air, requiring electrolysis under an inert atmosphere, making the reaction conditions and environment harsh. Non-AlCl3 ionic liquids have the problem of poor solubility of metal cations in the solvent, necessitating the addition of a solubilizer. Ionic liquids and other additives such as solubilizers and grain refiners are mostly organic solvents, which pose a risk of environmental pollution. Electroplating temperatures usually need to be maintained at 40~80℃, resulting in high energy consumption costs.

[0005] Electrodeposition in aqueous solutions has lower operational requirements, and acidic or neutral solutions are commonly used. However, the electrolysis efficiency is low, and harmful gases such as chlorine may be produced. For example, Shen Yijia et al. prepared an accelerator production reactor with 75% gallium content in hydrochloric acid solution by changing the ratio of nickel to gallium at a deposition temperature of 80℃. 68 Ge uses gallium-nickel alloy solid targets. After nickel plating to protect the target surface, the surface remains largely intact after irradiation. Since the solution environment for nickel electroplating is mostly acidic, and the plating solution in current gallium-nickel alloy electrodeposition research is also mostly acidic, electrodeposition in acidic solutions often has disadvantages such as difficulty in gallium deposition, difficulty in controlling the gallium-nickel ratio, and poor surface morphology.

[0006] Current research on the electrodeposition of gallium-nickel alloys in alkaline solutions is limited. This invention provides a method for electrodepositing gallium-nickel alloys in alkaline solutions. The electrolyte of this invention has a simple composition, is environmentally friendly and pollution-free, the operation process is simple, no harmful gases are generated during the electrodeposition process, and gallium-nickel alloy coatings can be prepared rapidly and efficiently in an open environment at room temperature. Summary of the Invention

[0007] This invention addresses the problems existing in the electrodeposition preparation of gallium-nickel alloys under acidic environments by providing a method for electrodepositing gallium-nickel alloys in an alkaline solution.

[0008] The present invention is implemented by the following steps: S1, mixing sodium gallate solution, nickel sulfate solution and ammonia water evenly to prepare an electroplating solution with a gallium ion concentration of 10g / L~20g / L, a nickel ion concentration of 0.2g / L~1g / L, and a pH of 10.6~12.3; S2, using one of copper sheet, aluminum sheet, stainless steel sheet, and platinum sheet as the working electrode, and stainless steel sheet as the auxiliary electrode, placing the electroplating solution prepared in step S1 in an electrolytic cell, installing the working electrode and auxiliary electrode in the electrolytic cell and connecting them to one of potentiostat or constant current power supply; S3, performing electrodeposition using an electrodeposition method, wherein the deposition time is 10~60min; S4, after electrodeposition, removing the working electrode from the device, rinsing it with deionized water and air-drying it naturally to obtain a gallium-nickel alloy coating. In this invention, the applicant, through theoretical and experimental verification, has formulated an electroplating solution with a concentration of 10 g / L to 20 g / L, a nickel ion concentration of 0.2 g / L to 1 g / L, and a pH of 10.6 to 12.3. Electrodeposition using this alkaline electroplating solution with these characteristics can prepare relatively good gallium-nickel alloys. The purpose of electrodeposition in a plating solution within this parameter range is that gallium is more easily deposited in an alkaline solution environment, resulting in a high-quality coating, while also allowing for the control of the gallium-nickel content ratio in the coating.

[0009] Preferably, step S1 specifically involves: first, mixing nickel sulfate solution and ammonia water evenly, then adding sodium gallate solution and stirring continuously until homogeneous, and finally adjusting the volume with deionized water to obtain the electroplating solution. The purpose is to ensure that the nickel ions in the alkaline plating solution form a complex with the ammonia water and do not exist as nickel hydroxide precipitate.

[0010] Preferably, in step S3, a potentiostat is used for electrodeposition at a deposition potential of -2.2V to -1.8V (vs. Hg / HgO). The purpose is to obtain gallium-nickel alloys with different morphologies on the working electrode within this potential range. A more negative deposition potential results in a faster metal deposition rate and a more porous coating; a more positive deposition potential results in a slower metal deposition rate and a denser coating. More preferably, in step S2, an Hg / HgO reference electrode is added, with a distance of 1cm to 2cm from the working electrode. An auxiliary electrode is positioned opposite both the working and reference electrodes, at a distance of 2cm to 3cm, and all electrodes are installed at the same height.

[0011] Preferably, in step S3, a constant current power supply is used for electrodeposition, and the cathode current is 76 A / dm. 2 ~96A / dm 2If the current density is too low, the electrodeposition rate is slow, the coating thickness is insufficient, and phenomena such as porosity and blistering are likely to occur; if the current density is too high, the electrodeposition rate is fast, which can easily cause high internal stress in the coating and lead to cracking.

[0012] Preferably, the working electrode and auxiliary electrode used in step S3 are pretreated before use. The pretreatment steps include: Step 1, mechanically polishing the working electrode and auxiliary electrode with a 0.05 μm alumina suspension; Step 2, ultrasonically cleaning the mechanically polished working electrode and auxiliary electrode in nitric acid solution and anhydrous ethanol for 20 min respectively; Step 3, rinsing the ultrasonically cleaned working electrode and auxiliary electrode with deionized water, and then drying them in a vacuum drying oven. The purpose is to remove dust, grease and other impurities from the electrode surface, allowing the coating to directly contact the substrate, improving the adhesion of the coating and the quality of the coating.

[0013] The beneficial effects of the present invention are as follows: (1) The present invention can rapidly and efficiently prepare gallium-nickel alloy coatings in an open environment at room temperature. (2) The electrolyte of the present invention has a simple composition, is environmentally friendly and pollution-free, has a simple operation process, and no harmful gases are generated during the electrodeposition process. (3) By adjusting the concentration of gallium and nickel elements in the plating solution, the present invention can simply and effectively control the content of nickel and gallium in the coating. The mass fraction of gallium in the coating is 65-85%, and the mass fraction of nickel is 15-35%. (4) The present invention has high electroplating efficiency, can effectively save costs, and can obtain a coating with a thickness of over 50 μm after 10 min of electroplating, and the coating structure is uniform. Attached Figure Description

[0014] Figure 1 This is a microscopic morphology diagram of the gallium-nickel alloy coating obtained in Example 1.

[0015] Figure 2 This is a microscopic morphology diagram of the gallium-nickel alloy coating obtained in Example 2. Implementation

[0016] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. Example

[0017] A method for preparing gallium-nickel alloy by electrodeposition in an alkaline solution includes the following steps: S1, sodium gallate solution, nickel sulfate solution, and ammonia water are mixed evenly to prepare an electroplating solution with a gallium ion concentration of 15 g / L, a nickel ion concentration of 0.2 g / L, and a pH of 12.3; S2, using a stainless steel sheet as the working electrode and a stainless steel sheet as the auxiliary electrode, the electroplating solution prepared in step S1 is placed in an electrolytic cell, and the working electrode, auxiliary electrode, and reference electrode are installed in the electrolytic cell and connected to a potentiostat; the working electrode is 1 cm... 2 The 316 stainless steel sheet has an auxiliary electrode of 4cm. 2 S3, Electrodeposition is performed using a potentiostat at a deposition potential of -1.8V (vs. Hg / HgO) for 10 minutes; S4, After electroplating, the working electrode is removed from the device, cleaned with deionized water, and air-dried to obtain a gallium-nickel alloy coating.

[0018] In step S2, the reference electrode is Hg / HgO, the distance between the reference electrode and the working electrode is 1.5cm, the auxiliary electrode is directly opposite the working electrode and the reference electrode, and the distance is 2.5cm. The installation height of each electrode is kept consistent.

[0019] The microstructure of the gallium-nickel alloy coating obtained in this embodiment is shown in the following figure. Figure 1 As shown, the deposits can be observed to exist in an irregular radial dendritic form, with a coating thickness of up to 100 μm. The coating contains 90–95% gallium and 5–10% nickel by mass. Example

[0020] A method for preparing gallium-nickel alloy by electrodeposition in an alkaline solution includes the following steps: S1, sodium gallate solution, nickel sulfate solution, and ammonia water are mixed evenly to prepare an electroplating solution with a gallium ion concentration of 20 g / L, a nickel ion concentration of 1 g / L, and a pH of 12; S2, using an aluminum sheet as the working electrode and a stainless steel sheet as the auxiliary electrode, the electroplating solution prepared in step S1 is placed in an electrolytic cell, and the working electrode, auxiliary electrode, and reference electrode are installed in the electrolytic cell and connected to a potentiostat; the working electrode is 1 cm... 2 The aluminum sheet has an auxiliary electrode of 4cm. 2 S3, Electrodeposition is performed using a potentiostat at a deposition potential of -2V (vs. Hg / HgO) for 30 minutes; S4, After electroplating, the working electrode is removed from the device, cleaned with deionized water, and air-dried to obtain a gallium-nickel alloy coating.

[0021] In step S2, the reference electrode is Hg / HgO, the distance between the reference electrode and the working electrode is 2cm, the auxiliary electrode is directly opposite the working electrode and the reference electrode, and the distance is 3cm. The installation height of each electrode is kept consistent.

[0022] The microstructure of the gallium-nickel alloy coating obtained in this embodiment is shown in the following figure. Figure 2 As shown, fine alloy particles are uniformly dispersed on the substrate. In addition, in some preferentially grown areas, the alloy exists in the form of larger, irregular dendritic structures. The coating contains 65-85% gallium and 15-35% nickel by mass. Example

[0023] A method for preparing gallium-nickel alloy by electrodeposition in an alkaline solution includes the following steps: S1, sodium gallate solution, nickel sulfate solution, and ammonia water are mixed evenly to obtain an electroplating solution with a gallium ion concentration of 16.5 g / L, a nickel ion concentration of 0.7 g / L, and a pH of 11.6; S2, using a platinum sheet as the working electrode and a stainless steel sheet as the auxiliary electrode, the electroplating solution prepared in step S1 is placed in an electrolytic cell, and the working electrode and auxiliary electrode are installed in the electrolytic cell and connected to a constant current power supply; the working electrode is 1 cm 2 The platinum sheet has an auxiliary electrode of 4cm. 2 S3, stainless steel sheet; electrodeposition is performed using a constant current power supply, wherein the cathode current density is 85 A / dm³. 2 The deposition time is 60 minutes; S4, after electroplating, the working electrode is removed from the device, cleaned with deionized water, and air-dried to obtain a gallium-nickel alloy coating. In step S1, the electroplating solution is prepared by: first, mixing nickel sulfate solution and ammonia water evenly, then adding sodium gallate solution, stirring continuously until uniform, and finally adjusting the volume with deionized water to obtain the electroplating solution. Example

[0024] A method for preparing gallium-nickel alloy by electrodeposition in an alkaline solution includes the following steps: S1, mixing sodium gallate solution, nickel sulfate solution, and ammonia water uniformly to obtain an electroplating solution with a gallium ion concentration of 18 g / L, a nickel ion concentration of 0.5 g / L, and a pH of 10.6; S2, using a copper sheet as the working electrode and a stainless steel sheet as the auxiliary electrode, placing the electroplating solution prepared in step S1 in an electrolytic cell, and installing the working electrode and auxiliary electrode in the electrolytic cell and connecting them to a constant current power supply; the working electrode is 1 cm... 2 The copper sheet has an auxiliary electrode of 4cm. 2 S3, stainless steel sheet; electrodeposition is performed using a constant current power supply, wherein the cathode current density is 60 A / dm³. 2 The deposition time is 30 minutes; S4, after the electroplating is completed, the working electrode is removed from the device, cleaned with deionized water and air-dried to obtain a gallium-nickel alloy coating.

[0025] The working electrode and auxiliary electrode used in step S3 are pretreated before use. The pretreatment steps include: Step 1, mechanically polishing the working electrode and auxiliary electrode with a 0.05μm alumina suspension; Step 2, ultrasonically cleaning the mechanically polished working electrode and auxiliary electrode in nitric acid solution and anhydrous ethanol for 20 minutes respectively; Step 3, cleaning the ultrasonically cleaned working electrode and auxiliary electrode with deionized water, and then drying them in a vacuum drying oven. Example

[0026] A method for preparing gallium-nickel alloy by electrodeposition in an alkaline solution includes the following steps: S1, mixing sodium gallate solution, nickel sulfate solution, and ammonia water uniformly to obtain an electroplating solution with a gallium ion concentration of 20 g / L, a nickel ion concentration of 0.2 g / L, and a pH of 11; S2, using an aluminum sheet as the working electrode and a stainless steel sheet as the auxiliary electrode, placing the electroplating solution prepared in step S1 in an electrolytic cell, and installing the working electrode and auxiliary electrode in the electrolytic cell and connecting them to a constant current power supply; the working electrode is 1 cm... 2 The aluminum sheet has an auxiliary electrode of 4cm. 2 S3, Stainless steel sheet; electrodeposition is performed using a constant current power supply, wherein the cathode current density is 100 A / dm³. 2 The deposition time is 10 min; S4, after the electroplating is completed, the working electrode is removed from the device, cleaned with deionized water and air-dried to obtain a gallium-nickel alloy coating. Example

[0027] A method for preparing gallium-nickel alloy by electrodeposition in an alkaline solution includes the following steps: S1, mixing sodium gallate solution, nickel sulfate solution, and ammonia water uniformly to obtain an electroplating solution with a gallium ion concentration of 10 g / L, a nickel ion concentration of 0.2 g / L, and a pH of 11.2; S2, using a platinum sheet as the working electrode and a stainless steel sheet as the auxiliary electrode, placing the electroplating solution prepared in step S1 in an electrolytic cell, and installing the working electrode, auxiliary electrode, and reference electrode in the electrolytic cell and connecting them to a potentiostat; the working electrode is 1 cm... 2 The platinum sheet has an auxiliary electrode of 4cm. 2 S3, Electrodeposition is performed using a potentiostat at a deposition potential of -2.2V (vs. Hg / HgO) for 60 minutes; S4, After electroplating, the working electrode is removed from the device, cleaned with deionized water, and air-dried to obtain a gallium-nickel alloy coating.

[0028] In step S2, the reference electrode is Hg / HgO, the distance between the reference electrode and the working electrode is 1cm, the auxiliary electrode is directly opposite the working electrode and the reference electrode, and the distance is 2cm. The installation height of each electrode is kept consistent.

Claims

1. A method for preparing gallium-nickel alloy by electrodeposition in an alkaline solution, characterized in that, The process includes the following steps: S1. First, mix nickel sulfate solution and ammonia water evenly, then add sodium gallate solution and stir continuously until uniform. Finally, dilute to volume with deionized water to obtain an electroplating solution with a gallium ion concentration of 10 g / L to 20 g / L, a nickel ion concentration of 0.2 g / L to 1 g / L, and a pH of 10.6 to 12.3; S2. Use one of copper sheet, stainless steel sheet, or platinum sheet as the working electrode and a stainless steel sheet as the auxiliary electrode. Place the electroplating solution prepared in step S1 in an electrolytic cell, install the working electrode and auxiliary electrode in the electrolytic cell, and connect them to a potentiostat; S3. Perform electrodeposition using an electrodeposition method. The deposition time is 10 to 60 minutes, and the deposition potential is -2.2 V to -1.8 V vs. Hg / HgO; S4. After electrodeposition, remove the working electrode from the device, wash it with deionized water, and air dry it naturally to obtain a gallium-nickel alloy coating.

2. The method for preparing gallium-nickel alloy by electrodeposition in an alkaline solution according to claim 1, characterized in that, In step S2, an Hg / HgO reference electrode is added. The distance between the reference electrode and the working electrode is 1cm to 2cm. The auxiliary electrode is directly opposite the working electrode and the reference electrode, with a distance of 2cm to 3cm. The installation height of each electrode is kept consistent.

3. The method for preparing gallium-nickel alloy by electrodeposition in an alkaline solution according to claim 1, characterized in that, The working electrode and auxiliary electrode used in step S3 are pretreated before use. The pretreatment steps include: Step 1, mechanically polishing the working electrode and auxiliary electrode with a 0.05μm alumina suspension; Step 2, ultrasonically cleaning the mechanically polished working electrode and auxiliary electrode in nitric acid solution and anhydrous ethanol for 20 minutes respectively; Step 3, cleaning the ultrasonically cleaned working electrode and auxiliary electrode with deionized water, and then drying them in a vacuum drying oven.

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