1. A method for electrodepositing a nickel coating in an environment-friendly manner is characterized by comprising the following specific operation steps:

(1) uniformly mixing choline chloride and nickel chloride, heating the mixture mixed with the choline chloride and the nickel chloride to 80 ℃, keeping the temperature constant until the two solids are dissolved, and generating transparent viscous liquid, namely choline chloride-nickel chloride ionic liquid;

(2) aiming at the generated choline chloride-nickel chloride ionic liquid, an externally-hung nickel sheet is taken as a soluble anode, and an externally-hung copper block is taken as a soluble cathode;

(3) immersing the two electrodes into the generated choline chloride-nickel chloride ionic liquid, and then connecting the two electrodes with an external power supply through a connecting wire so as to carry out constant-current electrodeposition;

(4) and after constant current electrodeposition, ultrasonically cleaning and drying the sample to finally obtain the deposited nickel coating.

2. The method of claim 1, wherein the nickel coating is electrodeposited in a green environment,

in the step (1), the mol ratio of choline chloride to nickel chloride in the choline chloride-nickel chloride ionic liquid is 1: 2.

3. The method of claim 1, wherein the nickel coating is electrodeposited in a green environment,

in the step (2), the distance between the soluble anode and the cathode is 2.5 cm.

4. The method of claim 1, wherein the nickel coating is electrodeposited in a green environment,

in the step (3), the constant current density is 10-15mA/cm²。

5. The method of claim 1, wherein the nickel coating is electrodeposited in a green environment,

in the step (3), the electrodeposition temperature is 85 to 95 ℃.

6. The method of claim 1, wherein the electrodeposition time is 60 to 90 minutes.

Background

The electrodeposition technique of nickel refers to a surface treatment method for depositing a layer of nickel on the surface of ferrous or non-ferrous metal articles by electrochemical action. The method is widely applied to manufacturing industries of machines, instruments, medical instruments, household appliances and the like. The present-stage nickel electrodeposition technology is mainly characterized by that the workpiece is made into cathode, and the anode of pure nickel plate is hung in the electrolyte prepared from nickel sulfate, sodium chloride and boric acid, and then the electrolytic electrodeposition is implemented. In order to obtain better surface quality, brightening agents such as sodium naphthalene disulfonate, saccharin, coumarin, p-toluenesulfonamide and the like are generally added. The addition of the relevant organic compounds increases the complexity of the operation on the one hand and, more importantly, also has a certain influence on the environment. How to eliminate the harm of the electrodeposition solution to the environment while obtaining high-quality metallic nickel becomes an urgent problem to be solved.

The eutectic solvent has the advantages of wide electrochemical window, good solubility and conductivity, low vapor pressure, good physical and chemical stability and the like, and is a novel green solvent. In the aspect of electrodepositing metal, because the eutectic solvent can selectively dissolve metal compounds, and has good conductivity and negative reduction potential, most of the metal which can be obtained in the aqueous solution can be electrodeposited at room temperature, and no side reaction exists, so that the obtained metal has good quality and high current efficiency. Meanwhile, the eutectic solvent has simple preparation process and low raw material price, and has wide application prospect in the technical field of nonferrous metallurgy. At the present stage, researchers take choline chloride and ethylene glycol ionic liquid in a molar ratio of 1:2 as a matrix system, and then add nickel chloride for constant voltage electroplating to obtain a nickel coating; wherein; ethylene glycol has a certain toxicity, and has a danger of causing combustion and explosion when meeting open fire, high heat or contacting with an oxidant.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a method for electrodepositing a nickel coating in an environment-friendly way.

The technical scheme is as follows: the invention relates to a method for electrodepositing a nickel coating in an environment-friendly way, which comprises the following specific operation steps:

(1) uniformly mixing choline chloride and nickel chloride, heating the mixture mixed with the choline chloride and the nickel chloride to 80 ℃, keeping the temperature constant until the two solids are dissolved, and generating transparent viscous liquid, namely choline chloride-nickel chloride ionic liquid;

(2) aiming at the generated choline chloride-nickel chloride ionic liquid, an externally-hung nickel sheet is taken as a soluble anode, and an externally-hung copper block is taken as a soluble cathode;

(3) immersing the two electrodes into the generated choline chloride-nickel chloride ionic liquid, and then connecting the two electrodes with an external power supply through a connecting wire so as to carry out constant-current electrodeposition;

(4) and after constant current electrodeposition, ultrasonically cleaning and drying the sample to finally obtain the deposited nickel coating.

Further, in the step (1), the molar ratio of choline chloride to nickel chloride in the choline chloride-nickel chloride ionic liquid is 1: 2.

Further, in the step (2), the distance between the soluble anode and the cathode is 2.5 cm.

Further, in the step (3), the constant current density is 10-15mA/cm²。

Further, in the step (3), the electrodeposition temperature is 85 to 95 ℃.

Further, the electrodeposition time is 60 to 90 minutes.

Has the advantages that: compared with the prior art, the method adopts choline chloride and nickel chloride as raw materials to form the ionic liquid, and prepares the metallic nickel coating by direct electrodeposition by taking the ionic liquid as electrolyte. The method has the advantages of simple raw materials, simple and easy operation, environmental protection, safety and no toxicity.

Drawings

FIG. 1 is a flow chart of the operation of the present invention;

FIG. 2 is an XRD pattern of a nickel coating obtained in example 1 of the present invention;

FIG. 3 is an EDS diagram of a nickel coating obtained in example 2 of the invention;

figure 4 is a surface XRD pattern of the nickel coating obtained in example 3 of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

As shown in FIG. 1, the method for electrodepositing a nickel coating in an environment-friendly manner, according to the present invention, comprises the following specific operation steps:

(1) uniformly mixing choline chloride and nickel chloride, heating the mixture mixed with the choline chloride and the nickel chloride to 80 ℃, keeping the temperature constant until the two solids are dissolved, and generating transparent viscous liquid, namely choline chloride-nickel chloride ionic liquid;

(2) aiming at the generated choline chloride-nickel chloride ionic liquid, an externally-hung nickel sheet is taken as a soluble anode, and an externally-hung copper block is taken as a soluble cathode;

(3) immersing the two electrodes into the generated choline chloride-nickel chloride ionic liquid, and then connecting the two electrodes with an external power supply through a connecting wire so as to carry out constant-current electrodeposition;

(4) and after constant current electrodeposition, ultrasonically cleaning and drying the sample to finally obtain the deposited nickel coating.

Further, in the step (1), the molar ratio of choline chloride to nickel chloride in the choline chloride-nickel chloride ionic liquid is 1: 2.

Further, in the step (2), the distance between the soluble anode and the cathode is 2.5 cm.

Further, in the step (3), the constant current density is 10-15mA/cm²。

Further, in the step (3), the electrodeposition temperature is 85 to 95 ℃.

Further, the electrodeposition time is 60 to 90 minutes.

Example 1:

1) the mol ratio of choline chloride to nickel chloride in the ionic liquid is 1:2, the choline chloride and the nickel chloride are uniformly mixed according to a certain proportion, then the mixture is heated to 75 ℃, the temperature is kept constant until the two solids are completely dissolved, and the generated transparent viscous liquid is the choline chloride-nickel chloride ionic liquid;

2) putting a nickel sheet as a soluble anode and a copper block as a cathode into the ions heated to 85 ℃ for constant current electrodeposition for 60 minutes, wherein the distance between the anode and the cathode is 2.5cm, and the current density is 10mA/cm²；

3) After electrodeposition, taking out the sample, ultrasonically cleaning the sample by using deionized water, and finally blowing the sample at low temperature by using a blower;

XRD analysis pattern of the resulting coating referring to fig. 2, it can be seen that the coating on the copper substrate is a nickel plating.

Example 2:

1) the mol ratio of choline chloride to nickel chloride in the ionic liquid is 1:2, the choline chloride and the nickel chloride are uniformly mixed according to a certain proportion, then the mixture is heated to 75 ℃, the temperature is kept constant until the two solids are completely dissolved, and the generated transparent viscous liquid is the choline chloride-nickel chloride ionic liquid;

2) putting a nickel sheet as a soluble anode and a copper block as a cathode into the ions heated to 90 ℃ for 75 minutes of constant current electrodeposition, wherein the distance between the anode and the cathode is 2.5cm, and the current density is 12mA/cm²；

3) After electrodeposition, taking out the sample, ultrasonically cleaning the sample by using deionized water, and finally drying the sample at low temperature by using a blower;

EDS map of the resulting coating referring to fig. 3, it can be seen that the coating on the copper substrate is a nickel plating.

Example 3:

1) the mol ratio of choline chloride to nickel chloride in the ionic liquid is 1:2, the choline chloride and the nickel chloride are uniformly mixed according to a certain proportion, then the mixture is heated to 75 ℃, the temperature is kept constant until the two solids are completely dissolved, and the generated transparent viscous liquid is the choline chloride-nickel chloride ionic liquid;

2) putting a nickel sheet as a soluble anode and a copper block as a cathode into the ions heated to 95 ℃ for constant current electrodeposition for 90 minutes, wherein the distance between the anode and the cathode is 2.5cm, and the current density is 15mA/cm²；

3) After electrodeposition, taking out the sample, ultrasonically cleaning the sample by using deionized water, and finally drying the sample at low temperature by using a blower; surface energy spectrum analysis of the resulting coating referring to fig. 4, it can be seen that the coating on the copper substrate is a nickel coating.