Preparation method of Raney nickel electrode

Abstract

The invention provides a Raney nickel electrode preparation method which comprises the following steps: 1, taking nickel powder with the particle size of 15-75 microns, nickel powder with the particle size of 75-150 microns and aluminum powder with the particle size of 15-75 microns, pouring the nickel powder, the nickel powder and the aluminum powder into a mixer, uniformly mixing without segregation phenomenon, and enabling the nickel powder, the nickel powder and the aluminum powder to respectively account for 70%-79%, 1%-10% and 20%; secondly, a plasma spraying technology is adopted, the temperature is regulated and controlled, so that the nickel powder and the aluminum powder with the particle size being 15-75 micrometers reach a molten state, and the nickel powder with the particle size being 75-150 micrometers reach a semi-molten state; spraying to a nickel net, and activating, cleaning and cutting to obtain a Raney nickel electrode; the nickel powder and the aluminum powder with different particle sizes are reasonably matched in the powder formula, the particle flying speed in spraying is properly increased, the spraying temperature is balanced, the powder with different particle sizes reaches different molten states, and therefore the large-particle nickel powder forms a good support in the coating, the bonding strength of the coating is remarkably improved, and the service life of the coating is prolonged. And the catalyst is not easy to fall off in the use process, so that the efficiency and the stability of the water electrolysis hydrogen production equipment are improved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production by electrolyzing water, and in particular to a method for preparing a Raney nickel electrode. Background Art

[0002] In the alkaline water electrolysis hydrogen production industry, the cathode electrode is usually prepared by Raney nickel catalyst. The existing technology mostly uses a mixture of 80% nickel powder and 20% aluminum powder with similar particle size for spraying, or other nickel powder and aluminum powder ratios. The sprayed nickel-aluminum coating needs to use an activation solution to remove aluminum. After activation, a small amount of unsupported shedding of nickel in the coating will occur. Although this formula has certain catalytic activity, under long-term working conditions, the bonding strength of the coating is weak, which is easy to cause peeling, affecting the electrode life and electrolysis efficiency. Summary of the invention

[0003] The invention aims to provide a preparation method of a Raney nickel electrode, which adopts a unique powder formula and a spraying process matched therewith, and reasonably matches nickel powder and aluminum powder of different particle sizes in the powder formula; in order to make the coating after spraying more dense, the flying speed of particles in the spraying is appropriately increased, and the spraying temperature is balanced, so that powders of different particle sizes reach different melting states, so that large-particle nickel powder forms good support in the coating.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for preparing a Raney nickel electrode comprises the following steps:

[0006] Step 1: Pour nickel powder with a particle size of 15 to 75 microns, nickel powder with a particle size of 75 to 150 microns and aluminum powder with a particle size of 15 to 75 microns into a mixer and mix them evenly without segregation. The proportions of nickel powder with a particle size of 15 to 75 microns, nickel powder with a particle size of 75 to 150 microns and aluminum powder with a particle size of 15 to 75 microns in the mixture are 70% to 79%, 1% to 10% and 20% respectively;

[0007] The second step: using plasma spraying technology, adjusting the temperature to make the nickel powder and aluminum powder with a particle size of 15 to 75 microns reach a molten state, and the nickel powder with a particle size of 75 to 150 microns reach a semi-molten state; and spraying it onto the nickel mesh and activating, cleaning and cutting it to obtain the Raney nickel electrode.

[0008] In one embodiment,

[0009] Step 1: Pour nickel powder with a particle size of 15 to 45 microns, nickel powder with a particle size of 75 to 115 microns and aluminum powder with a particle size of 15 to 45 microns into a mixer and mix them evenly without segregation. The proportions of nickel powder with a particle size of 15 to 45 microns, nickel powder with a particle size of 75 to 115 microns and aluminum powder with a particle size of 15 to 45 microns in the mixture are 75%, 5% and 20% respectively;

[0010] The second step: using plasma spraying technology, regulating the temperature to make nickel powder and aluminum powder with a particle size of 15 to 45 microns reach a molten state, and nickel powder with a particle size of 75 to 115 microns reach a semi-molten state; and spraying it onto the nickel mesh and activating, cleaning and cutting it to obtain a Raney nickel electrode.

[0011] In one embodiment, the bulk density of nickel powder with a particle size of 15 to 45 microns is 1.612 g / cm 3 The bulk density of nickel powder with a particle size of 75 to 115 microns is 1.733 g / cm 3 The bulk density of aluminum powder with a particle size of 15 to 45 microns is 1.470 g / cm 3 .

[0012] In one embodiment, the nickel mesh needs to be ultrasonically cleaned to remove grease from its surface, dried, and then roughened using an automatic sandblasting machine, and then cleaned of surface impurities and dried.

[0013] In one embodiment, the powder prepared in the first step is dried at a temperature of 80° C. for 2 to 4 hours.

[0014] In one embodiment, the plasma spraying process is specifically as follows: the powder prepared in the first step is placed in the powder supply system of the atmospheric plasma spraying equipment, the main gas flow rate of the spraying is set to 40-55NLPM, the secondary gas flow rate is 1-5NLPM, the spraying current is 500-850A, the spraying distance is 80-180mm, the spraying speed is 500-1000mm / s, the powder feeding speed is 70-200g / min, the stepping is 3-6mm, the carrier gas is 4-12NLPM, the spraying angle is 70°-90°, the substrate temperature is 50-180°C, and the powder feeding angle is 75-90° for spraying operation.

[0015] Compared with the prior art, the present invention has the following advantages or beneficial effects:

[0016] The invention provides a preparation method of a Raney nickel electrode, which adopts a unique powder formula and a spraying process matched therewith, wherein nickel powder and aluminum powder of different particle sizes are reasonably matched in the powder formula; in order to make the coating after spraying more dense, the flying speed of particles in the spraying is appropriately increased, and the spraying temperature is balanced, so that powders of different particle sizes reach different melting states, so that large-particle nickel powder forms a good support in the coating, the bonding strength of the coating is significantly improved, and the catalyst is less likely to fall off during use, thereby improving the efficiency and stability of water electrolysis hydrogen production equipment; secondly, by optimizing the powder formula and the preparation process, the coating has better aging resistance and prolongs the service life of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Attached Figure 1 is a surface metallographic image of the material produced in the first embodiment;

[0018] Attached Figure 2 Surface metallographic image of the material produced in the comparative example. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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 creative work are within the scope of protection of the present invention.

[0020] Example 1

[0021] 1) Powder preparation

[0022] The bulk density of the powder raw materials was tested. The bulk density of nickel powder with a particle size of 15 to 45 microns was 1.612 g / cm3, the bulk density of nickel powder with a particle size of 75 to 115 microns was 1.733 g / cm3, and the bulk density of aluminum powder with a particle size of 15 to 45 microns was 1.470 g / cm3.

[0023] Weigh 750 g of nickel powder with a particle size of 15 to 45 microns, 50 g of nickel powder with a particle size of 75 to 115 microns, and 200 g of aluminum powder with a particle size of 15 to 45 microns;

[0024] The three powders are placed in a powder mixing device and stirred evenly without allowing segregation to occur, thereby obtaining Raney nickel electrode powder.

[0025] 2) Electrode pretreatment

[0026] Take the cathode nickel mesh, clean the surface grease with ultrasonic, dry it, use an automatic sandblasting machine to roughen its surface, clean the surface impurities and dry it.

[0027] 3) Spraying

[0028] The prepared Raney nickel electrode powder is dried at 80°C for 2 to 4 hours. After drying, the powder is placed in a powder supply system of an atmospheric plasma spraying device. The main gas flow rate for spraying is 40 to 55 NLPM, the secondary gas flow rate is 1 to 5 NLPM, the spraying current is 500 to 850 A, the spraying distance is 80 to 180 mm, the spraying speed is 500 to 1000 mm / s, the powder feeding speed is 70 to 200 g / min, the stepping distance is 3 to 6 mm, the carrier gas is 4 to 12 NLPM, the spraying angle is 70° to 90°, the substrate temperature is 50 to 180°C, and the powder feeding angle is 75 to 90°. The spraying temperature is adjusted so that the nickel powder with a particle size of 15 to 45 microns and the aluminum powder with a particle size of 15 to 45 microns are in a melted state, and the nickel powder with a particle size of 75 to 115 microns is in a semi-molten state for spraying.

[0029] 4) Activation

[0030] Place the sprayed electrode into the activation tank, use a special activation solution, and control the solution concentration, temperature and activation time.

[0031] 5) Cleaning and drying

[0032] The activated electrode is cleaned, the impurities on the surface are removed and the electrode is dried.

[0033] 6) Cropping

[0034] According to actual use requirements, the electrodes can be cut into appropriate sizes and used in alkaline water electrolysis hydrogen production equipment.

[0035] Example 2

[0036] 1) Powder preparation

[0037] The bulk density of the powder raw materials was tested. The bulk density of nickel powder with a particle size of 15 to 45 microns was 1.612 g / cm3, the bulk density of nickel powder with a particle size of 75 to 115 microns was 1.733 g / cm3, and the bulk density of aluminum powder with a particle size of 15 to 45 microns was 1.470 g / cm3.

[0038] Weigh 700 g of nickel powder with a particle size of 15 to 45 microns, 100 g of nickel powder with a particle size of 75 to 115 microns, and 200 g of aluminum powder with a particle size of 15 to 45 microns;

[0039] The three powders are placed in a powder mixing device and stirred evenly without allowing segregation to occur, thereby obtaining Raney nickel electrode powder.

[0040] 2) Electrode pretreatment

[0041] Take the cathode nickel mesh, clean the surface grease with ultrasonic, dry it, use an automatic sandblasting machine to roughen its surface, clean the surface impurities and dry it.

[0042] 3) Spraying

[0043] The prepared Raney nickel electrode powder is dried at 80°C for 2 to 4 hours. After drying, the powder is placed in a powder supply system of an atmospheric plasma spraying device. The main gas flow rate for spraying is 40 to 55 NLPM, the secondary gas flow rate is 1 to 5 NLPM, the spraying current is 500 to 850 A, the spraying distance is 80 to 180 mm, the spraying speed is 500 to 1000 mm / s, the powder feeding speed is 70 to 200 g / min, the stepping distance is 3 to 6 mm, the carrier gas is 4 to 12 NLPM, the spraying angle is 70° to 90°, the substrate temperature is 50 to 180°C, and the powder feeding angle is 75 to 90°. The spraying temperature is adjusted so that the nickel powder with a particle size of 15 to 45 microns and the aluminum powder with a particle size of 15 to 45 microns are in a melted state, and the nickel powder with a particle size of 75 to 115 microns is in a semi-molten state for spraying.

[0044] 4) Activation

[0045] Place the sprayed electrode into the activation tank, use a special activation solution, and control the solution concentration, temperature and activation time.

[0046] 5) Cleaning and drying

[0047] The activated electrode is cleaned, the impurities on the surface are removed and the electrode is dried.

[0048] 6) Cropping

[0049] According to actual use requirements, the electrodes can be cut into appropriate sizes and used in alkaline water electrolysis hydrogen production equipment.

[0050] Example 3

[0051] 1) Powder preparation

[0052] The bulk density of the powder raw materials was tested. The bulk density of nickel powder with a particle size of 15 to 45 microns was 1.612 g / cm3, the bulk density of nickel powder with a particle size of 75 to 115 microns was 1.733 g / cm3, and the bulk density of aluminum powder with a particle size of 15 to 45 microns was 1.470 g / cm3.

[0053] Weigh 780 g of nickel powder with a particle size of 15 to 45 microns, 20 g of nickel powder with a particle size of 75 to 115 microns, and 200 g of aluminum powder with a particle size of 15 to 45 microns;

[0054] The three powders are placed in a powder mixing device and stirred evenly without allowing segregation to occur, thereby obtaining Raney nickel electrode powder.

[0055] 2) Electrode pretreatment

[0056] Take the cathode nickel mesh, clean the surface grease with ultrasonic, dry it, use an automatic sandblasting machine to roughen its surface, clean the surface impurities and dry it.

[0057] 3) Spraying

[0058] The prepared Raney nickel electrode powder is dried at 80°C for 2 to 4 hours. After drying, the powder is placed in a powder supply system of an atmospheric plasma spraying device. The main gas flow rate for spraying is 40 to 55 NLPM, the secondary gas flow rate is 1 to 5 NLPM, the spraying current is 500 to 850 A, the spraying distance is 80 to 180 mm, the spraying speed is 500 to 1000 mm / s, the powder feeding speed is 70 to 200 g / min, the stepping distance is 3 to 6 mm, the carrier gas is 4 to 12 NLPM, the spraying angle is 70° to 90°, the substrate temperature is 50 to 180°C, and the powder feeding angle is 75 to 90°. The spraying temperature is adjusted so that the nickel powder with a particle size of 15 to 45 microns and the aluminum powder with a particle size of 15 to 45 microns are in a melted state, and the nickel powder with a particle size of 75 to 115 microns is in a semi-molten state for spraying.

[0059] 4) Activation

[0060] Place the sprayed electrode into the activation tank, use a special activation solution, and control the solution concentration, temperature and activation time.

[0061] 5) Cleaning and drying

[0062] The activated electrode is cleaned, the impurities on the surface are removed and the electrode is dried.

[0063] 6) Cropping

[0064] According to actual use requirements, the electrodes can be cut into appropriate sizes and used in alkaline water electrolysis hydrogen production equipment.

[0065] Comparative Example

[0066] 1) Powder preparation

[0067] The bulk density of the powder raw materials was tested. The bulk density of nickel powder with a particle size of 15 to 45 microns was 1.612 g / cm3, and the bulk density of aluminum powder with a particle size of 15 to 45 microns was 1.470 g / cm3.

[0068] Weigh 800g of nickel powder with a particle size of 15 to 45 microns and 200g of aluminum powder with a particle size of 15 to 45 microns;

[0069] The two powders are placed in a powder mixing device and stirred evenly without allowing segregation to occur, thereby obtaining Raney nickel electrode powder.

[0070] 2) Electrode pretreatment

[0071] Take the cathode nickel mesh, clean the surface grease with ultrasonic, dry it, use an automatic sandblasting machine to roughen its surface, clean the surface impurities and dry it.

[0072] 3) Spraying

[0073] The prepared Raney nickel electrode powder is dried at 80°C for 2 to 4 hours. After drying, the powder is placed in a powder supply system of an atmospheric plasma spraying device. The main gas flow rate for spraying is 40 to 55 NLPM, the secondary gas flow rate is 1 to 5 NLPM, the spraying current is 500 to 850 A, the spraying distance is 80 to 180 mm, the spraying speed is 500 to 1000 mm / s, the powder feeding speed is 70 to 200 g / min, the stepping distance is 3 to 6 mm, the carrier gas is 4 to 12 NLPM, the spraying angle is 70° to 90°, the substrate temperature is 50 to 180°C, and the powder feeding angle is 75 to 90°. The spraying temperature is adjusted so that the nickel powder with a particle size of 15 to 45 microns and the aluminum powder with a particle size of 15 to 45 microns are in a melted state, and the nickel powder with a particle size of 75 to 115 microns is in a semi-molten state for spraying.

[0074] 4) Activation

[0075] Place the sprayed electrode into the activation tank, use a special activation solution, and control the solution concentration, temperature and activation time.

[0076] 5) Cleaning and drying

[0077] The activated electrode is cleaned, the impurities on the surface are removed and the electrode is dried.

[0078] 6) Cropping

[0079] According to actual use requirements, the electrodes can be cut into appropriate sizes and used in alkaline water electrolysis hydrogen production equipment.

[0080] Performance test: The new formula is significantly better than the traditional formula in terms of binding force

[0081] The ultrasonic weight loss method was used to detect the coating adhesion. The experimental results are shown in the table below. The ultrasonic time was 4h, the temperature was 30℃±1℃, and the Raney nickel powder formula with added large-particle nickel powder had a lower ultrasonic weight loss rate than the coating without addition, indicating that the addition of large-particle nickel powder can increase the coating adhesion. At the same time, by comparing Examples 1 to 3, it is proved that the addition of 5% large-particle nickel powder has a better effect.

[0082]

[0083] At the same time, by comparing Figure 1 and Figure 2 It can be seen that the surface metallographic images of the two schemes have a high degree of similarity, but Figure 1 There are large particles in the coating, and the large-particle nickel powder can form a good support in the coating, which significantly improves the bonding strength of the coating and makes the catalyst less likely to fall off during use, thereby improving the efficiency and stability of the water electrolysis hydrogen production equipment.

[0084] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0085] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a Raney nickel electrode, characterized in that: The following steps are involved: Step 1: Pour nickel powder with a particle size of 15 to 75 microns, nickel powder with a particle size of 75 to 150 microns and aluminum powder with a particle size of 15 to 75 microns into a mixer and mix them evenly without segregation. The proportions of nickel powder with a particle size of 15 to 75 microns, nickel powder with a particle size of 75 to 150 microns and aluminum powder with a particle size of 15 to 75 microns in the mixture are 70% to 79%, 1% to 10% and 20% respectively; The second step: using plasma spraying technology, adjusting the temperature to make the nickel powder and aluminum powder with a particle size of 15 to 75 microns reach a molten state, and the nickel powder with a particle size of 75 to 150 microns reach a semi-molten state; and spraying it onto the nickel mesh and activating, cleaning and cutting it to obtain the Raney nickel electrode.

2. The method for preparing a Raney nickel electrode according to claim 1, characterized in that: Step 1: Pour nickel powder with a particle size of 15 to 45 microns, nickel powder with a particle size of 75 to 115 microns and aluminum powder with a particle size of 15 to 45 microns into a mixer and mix them evenly without segregation. The proportions of nickel powder with a particle size of 15 to 45 microns, nickel powder with a particle size of 75 to 115 microns and aluminum powder with a particle size of 15 to 45 microns in the mixture are 75%, 5% and 20% respectively; The second step: using plasma spraying technology, regulating the temperature to make nickel powder and aluminum powder with a particle size of 15 to 45 microns reach a molten state, and nickel powder with a particle size of 75 to 115 microns reach a semi-molten state; and spraying it onto the nickel mesh and activating, cleaning and cutting it to obtain a Raney nickel electrode.

3. The method for preparing a Raney nickel electrode according to claim 2, characterized in that: The bulk density of nickel powder with a particle size of 15 to 45 microns is 1.612 g / cm 3 The bulk density of nickel powder with a particle size of 75 to 115 microns is 1.733 g / cm 3 The bulk density of aluminum powder with a particle size of 15 to 45 microns is 1.470 g / cm 3 .

4. The method for preparing a Raney nickel electrode according to claim 2, characterized in that: The nickel mesh needs to be ultrasonically cleaned to remove grease from its surface, dried, and then roughened using an automatic sandblasting machine, and then cleaned of surface impurities and dried.

5. The method for preparing a Raney nickel electrode according to claim 2, characterized in that: The powder prepared in the first step is dried at 80° C. for 2 to 4 hours.

6. The method for preparing a Raney nickel electrode according to claim 5, characterized in that: The plasma spraying process is specifically as follows: the powder prepared in the first step is placed in the powder supply system of the atmospheric plasma spraying equipment, the main gas flow rate of the spraying is 40-55 NLPM, the secondary gas flow rate is 1-5 NLPM, the spraying current is 500-850A, the spraying distance is 80-180 mm, the spraying speed is 500-1000 mm / s, the powder feeding speed is 70-200 g / min, the stepping is 3-6 mm, the carrier gas is 4-12 NLPM, the spraying angle is 70°-90°, the substrate temperature is 50-180°C, and the powder feeding angle is 75-90° for spraying operation.

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