CN110093649B - Aluminum alloy end plate coating, preparation method thereof, end plate containing aluminum alloy end plate coating and fuel cell - Google Patents

Aluminum alloy end plate coating, preparation method thereof, end plate containing aluminum alloy end plate coating and fuel cell Download PDF

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CN110093649B
CN110093649B CN201810097229.XA CN201810097229A CN110093649B CN 110093649 B CN110093649 B CN 110093649B CN 201810097229 A CN201810097229 A CN 201810097229A CN 110093649 B CN110093649 B CN 110093649B
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end plate
layer
aluminum alloy
surface layer
coating
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CN110093649A (en
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付超
王亚蒙
倪蕾蕾
季文姣
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Shanghai Electric Group Corp
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Shanghai Electric Group Corp
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
    • C25D11/08—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing inorganic acids
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
    • C25D11/10—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing organic acids
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/16—Pretreatment, e.g. desmutting
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
    • C25D11/02—Anodisation
    • C25D11/04—Anodisation of aluminium or alloys based thereon
    • C25D11/18—After-treatment, e.g. pore-sealing
    • C25D11/24—Chemical after-treatment
    • C25D11/246—Chemical after-treatment for sealing layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
    • H01M8/0204—Non-porous and characterised by the material
    • H01M8/0223—Composites
    • H01M8/0228—Composites in the form of layered or coated products
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Abstract

The invention discloses an aluminum alloy end plate coating, a preparation method thereof, an end plate containing the aluminum alloy end plate coating and a fuel cell. The preparation method of the aluminum alloy end plate coating comprises the steps of performing sand blasting, cleaning, anodic oxidation and hole sealing on the aluminum alloy end plate, taking chromic acid or a mixed solution of boric acid and sulfuric acid or a mixed solution of adipic acid and sulfuric acid as an electrolyte, adding a mixed additive into the electrolyte, controlling the anodic oxidation temperature to be-5-15 ℃, the oxidation time to be 15-40 min, the working voltage to be 15-25V, and the current density to be 1.5-4.5A/dm2The maximum value of the microhardness of the prepared end plate coating can reach 245.2Hv, the bonding strength exceeds 100MPa, the damage to the surface of the end plate in the assembly process of the galvanic pile can be effectively avoided, the corrosion of the aluminum alloy end plate in the service process is avoided, the stability of the galvanic pile is improved, and the service life of the galvanic pile is prolonged.

Description

Aluminum alloy end plate coating, preparation method thereof, end plate containing aluminum alloy end plate coating and fuel cell
Technical Field
The invention relates to an aluminum alloy end plate coating, a preparation method thereof, an end plate containing the aluminum alloy end plate coating and a fuel cell.
Background
The proton exchange membrane fuel cell takes hydrogen as fuel, chemical energy is converted into electric energy through an electrochemical method, and a reaction product is water, so that the proton exchange membrane fuel cell has no pollution to the environment. The proton exchange membrane fuel cell has the advantages of high energy conversion efficiency (50-80%), quick start at low temperature, high power density and the like, can be applied to new energy automobiles, distributed energy sources, portable small power sources and the like, and is widely concerned by governments, energy sources and automobile enterprises at present.
The electric pile is the core module of the proton exchange membrane fuel cell generating system, and the conventional fuel cell mainly comprises a membrane electrode, an anode plate, a cathode plate, an insulation plate, a collector plate, an end plate, a sealing layer and other parts. The end plate is one of the key components of the stack, and is connected with each battery assembly through the fastening component to form a stable stack structure, and the pretightening force is uniformly distributed to each assembly in the stack, so that the end plate material needs to have certain strength. Since the pem fuel cell generally operates at a temperature of 80 ℃, the end plates need to maintain a certain strength at this temperature, and softening deformation cannot occur. In addition, in the operation process of the fuel cell, the air inlet needs to be humidified, and water generated by reaction is discharged along with gas, so that high-humidity gas or gas-liquid two-phase flow is arranged at the inlet and the outlet, the interior of the cell is weakly acidic, and the end plate is required to be resistant to acid corrosion. In order to increase the weight specific power and the volume specific power of the entire stack, the end plates need to be as low in density as possible while maintaining sufficient strength. Therefore, the end plate applicable to the proton exchange membrane fuel cell stack is required to have properties such as good insulation, corrosion resistance, low density, and high strength.
The end plate materials commonly used at present mainly include metals, engineering plastics and polysulfone materials, wherein metal materials such as metal titanium plates and stainless steel plates have high strength, but an insulating plate (engineering plastics) needs to be added between the current collecting plate and the end plate, which complicates the fuel cell system. The end plates made of engineering plastics and polysulfone materials are not good enough in thermal stability, are easy to deform at the operating temperature of the battery pack, and are usually heavy in design due to the fact that the end plates made of the materials need to keep certain strength.
The existing proton exchange membrane fuel cell end plate has the following problems:
1. the collector plates and end plates of a pem fuel cell stack are made of metal materials, and an insulating plate needs to be added between the collector plates and the end plates, so that the number of parts is increased, and the sealing difficulty and the assembly complexity of the stack are increased.
2. By adopting the existing anodic oxidation process with constant current density, the coating strength can not meet the requirement of a high-performance fuel cell, and the types of the oxidation film materials are greatly limited. The existing constant-voltage anodic oxidation process is adopted, and then the anode is sealed in boiling water, so that defects exist in an oxide layer, corrosion can occur in the running process of a battery pack, and the requirement of a fuel cell on the performance of an end plate cannot be met.
3. The metal material is adopted as the material of the end plate of the fuel cell, because the fluid through holes are needed to be formed on the end plate, the fluid enters each monocell through the through holes on the collector plate, and because the fluid erodes the through holes of the collector plate for a long time, the plating layer of the collector plate is corroded or falls off, the surface of the collector plate is also corroded, and metal ions in the collector plate can be brought into the cathode and anode catalyst layers of the fuel cell in a large amount, so that the catalyst is poisoned, and the performance of.
4. The proton exchange membrane fuel cell stack usually only applies one-time pre-pressing force during the assembly process, which easily causes the fracture of the bipolar plate and the damage of the coating on the surface of the end plate.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the problem of fuel cell lightweight, structure simplify, avoid the damage to appear in the pile assembly process end plate surface, promote stand wear and tear, hardness and bonding strength, promote corrosion resisting property, effectively prevent metal ion to get into the catalysis layer, avoid metal ion to poison the catalyst that causes, improve the stability of pile, extension pile life.
The invention provides a preparation method of an aluminum alloy end plate coating, which comprises the steps of carrying out sand blasting, cleaning, anodic oxidation and hole sealing treatment on the aluminum alloy end plate.
Wherein the electrolyte in the anodic oxidation is 30-50 g/L chromic acid; or a mixed solution of 5-10 g/L boric acid and 30-50 g/L sulfuric acid, wherein the mixing volume ratio of the boric acid to the sulfuric acid is 1: 0.5-3; or a mixed solution of 10-25 g/L adipic acid and 30-50 g/L sulfuric acid, wherein the mixing volume ratio of the adipic acid to the sulfuric acid is 1: 1-5.
Wherein, the aluminum alloy end plate is a conventional aluminum alloy end plate. Aluminum alloy end plates are commercially available from Shanghai Bingmao mechanical parts, Inc. Wherein, further, the selected aluminum alloy end plate can have the elastic modulus of 70GPa, the Poisson ratio of 0.33 and the tensile strength of 100-300 Mpa.
Wherein, the electrolyte is addedAnd (3) mixing additives, wherein the content of the mixed additives in the total solution is 0.1-3 g/L. Wherein, the content of the mixed additive in the total solution is 0.1-0.6 g/L. Wherein the mixed additive is HfOCl2And isopropanol, the mass ratio of the two is 1: 3-5; or the mixed additive is TaCl5And ethanol, the mass ratio of the two is 1: 3-5; alternatively, the mixed additive is WCl4And isopropanol, the mass ratio of the two is 1: 8-12; or, the mixed additive is ReCl3And ethanol, wherein the mass ratio of the ethanol to the ethanol is 1: 3-5.
Wherein the anodic oxidation is controlled under the conditions of-5-15 ℃, the oxidation time of 15-40 min, the working voltage of 15-25V and the current density of 1.5-4.5A/dm2。
Wherein, the anode oxidation is further controlled under the conditions of 5-10 ℃ of temperature, 15-40 min of oxidation time, 15-20V of working voltage and 1.5-4.5A/dm of current density2。
Wherein, further, a high-purity lead plate or a graphite plate is selected as a cathode material.
And further, cleaning the surface of the end plate by adopting alcohol before sand blasting of the end plate.
And further, the sand blasting treatment is to perform sand blasting treatment on the end plate by selecting 10-25 meshes of corundum sand under the air pressure of 0.5-1 MPa. Wherein, furthermore, after the sand blasting, the surface cleanliness reaches above grade Sa 2.
Wherein, furthermore, the cleaning treatment after sand blasting selects 15-35 g/L NaOH and 20-30 g/L Na2CO3The mixed solution or the neutral organic solvent is used as an oil removing agent, the end plate is cleaned for 1-5 min at the temperature of 20-45 ℃, and then 300-400 g/L HNO is selected3The solution is used as a pickling agent, and the end plate is cleaned for 1-5 min at the temperature of 20-25 ℃; wherein, further, the NaOH and Na2CO3The ratio of (A) to (B) is 1: 2-5. Wherein, furthermore, the neutral organic solvent is acetone.
Wherein the end plate is cleaned again after said anodising. Wherein, furthermore, deionized water is selected for cleaning.
Wherein, the hole sealing treatment is carried out by immersing the end plate into a potassium dichromate solution. The potassium dichromate solution is commercially available from Shanghai Allantin Biotechnology Ltd at a specification of 1/24mol/L (0.25N). Controlling the concentration of a potassium dichromate solution in hole sealing treatment to be 40-75 g/L, controlling the pH to be 5-7, controlling the temperature to be 80-95 ℃ and controlling the time to be 20-45 min.
The invention provides a coating prepared by the preparation method, which comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate. Wherein the surface layer has a microporous layer therein.
Wherein the thickness of the barrier layer is 0.01-10 μm, the thickness of the surface layer is 10-100 μm, and the thickness of the sealing layer is 1-20 μm. Wherein the porosity of the coating is 1-5%.
Furthermore, the thickness of the blocking layer is 8-10 μm, the thickness of the surface layer is 40-50 μm, and the thickness of the sealing layer is 2-3 μm. Wherein the porosity of the coating is 3-5%.
Wherein, further, the coating is of an equiaxed crystal-like structure, and the surface layer and the microporous layer are parallel to each other.
The hardness is tested by adopting a microhardness tester, and the porosity is tested by adopting an SEM picture.
The invention provides an aluminum alloy end plate comprising the coating.
The invention provides a proton exchange membrane fuel cell comprising the aluminum alloy end plate, which comprises an aluminum alloy end plate, a current collecting plate, an anode plate, a cathode plate and a sealing layer.
And (3) microhardness testing: micro-microhardness testing, namely selecting 5 different positions of a single sample for testing; d1 and D2 are the length of the diagonal of the two indentations, and the average value of the two values is generally tested; HV is Vickers hardness, HRC is Rockwell hardness, HB is Brinell hardness; the higher the hardness value, the better the wear resistance.
And (3) testing the bonding strength: and (3) adhering the high-strength adhesive to the customized joint, testing the force required for stripping the coating from the base metal by using a material testing machine, and calculating the bonding strength of the coating and the aluminum alloy end plate according to the contact area of the joint.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The reagents and starting materials used in the present invention are commercially available.
The positive progress effects of the invention are as follows:
1. according to the invention, the aluminum alloy is used as the end plate, the insulating layer is formed on the surface of the end plate in situ, the insulating layer is not required to be additionally arranged between the collector plate and the end plate, the end plate and the collector plate are integrated, the galvanic pile structure is simplified, and the requirement of light weight is met.
2. The anode oxidation is adopted to prepare the end plate coating, so that the wear resistance and the higher hardness and bonding strength are improved, the highest value of the microhardness can reach 245.2Hv, the bonding strength exceeds 100MPa, and the damage to the surface of the end plate in the assembly process of the galvanic pile can be effectively avoided.
3. The anode oxidation is adopted to prepare the end plate coating to form a barrier layer, the coating is compact and has good corrosion resistance, the prepared coating does not fall off or lose efficacy in the service process, the end plate can be ensured not to be corroded in the service process, metal ions can be effectively prevented from entering the catalyst layer, the metal ions are prevented from poisoning the catalyst, the stability of the galvanic pile is improved, and the service life of the galvanic pile is prolonged.
Drawings
Fig. 1 is a schematic view of an end plate with a coating prepared in examples 1 to 10 and without being subjected to a sealing treatment, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
Fig. 2 is a schematic diagram of the coated end plate subjected to the sealing treatment prepared in examples 1 to 10, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
Fig. 3 shows the results of the adhesion test of the end plate coating of example 1.
Fig. 4 shows the results of the adhesion test of the end plate coating of example 2.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.
Example 1
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Cleaning the end plate for 3min at 25 ℃; adopts 300g/L HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting 35g/L chromic acid as electrolyte in anodic oxidation; the additive is HfOCl2And isopropanol, wherein the mass ratio of the isopropanol is 1:4, and the addition content is 0.5g/L of the mixed additive in the total solution. The anodic oxidation is controlled under the conditions of 5 ℃ of temperature, 30min of time, 15V of working voltage and 1.5A/dm of current density2The cathode material is a high-purity lead plate. The schematic diagram of the prepared coated end plate without hole sealing treatment is shown in fig. 1, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
Table 1 shows microhardness test data for example 1.
TABLE 1
Figure GDA0002769362940000061
Fig. 3 is a result of the end plate bonding force test of example 1, and it can be seen from the test result that the bonding force of the end plate is 30-32N, and the bonding strength of the obtained coatings exceeds 100MPa and is a coating with high bonding strength, calculated according to the contact surface with the diameter of the diamond joint of 0.2 mm.
The prepared coating does not fall off or lose efficacy in the service process.
Example 2
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Cleaning the end plate for 3min at 25 ℃; adopts 300g/L HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting a mixed solution of 10g/L adipic acid and 35g/L sulfuric acid with a volume ratio of 1:5 as an electrolyte in anodic oxidation; the additive is HfOCl2And isopropanol, wherein the mass ratio of the isopropanol is 1:5, and the addition content is 0.5g/L of the mixed additive in the total solution. The anodic oxidation is controlled under the conditions of 5 ℃ of temperature, 30min of time, 15V of working voltage and 4.5A/dm of current density2The cathode material is a high-purity lead plate. The schematic diagram of the prepared coated end plate without hole sealing treatment is shown in fig. 1, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
Fig. 4 shows the results of the end plate bonding force test of example 2, and it can be seen from the test results that the bonding force of the end plate is 26 to 29N, and the bonding strength of the obtained coatings exceeds 100MPa and is a coating with high bonding strength, calculated according to the contact surface with the diameter of the diamond joint of 0.2 mm.
The prepared coating is of an equiaxed crystal-like structure, and the surface coating and the microporous layer are parallel to each other.
The prepared coating does not fall off or lose efficacy in the service process.
Example 3
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Cleaning the end plate for 3min at 25 ℃; adopts 300g/L HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting a mixed solution of 6g/L boric acid and 40g/L sulfuric acid with a volume ratio of 1:1 as an electrolyte in anodic oxidation; adding mixed additive TaCl5And ethanol, wherein the mass ratio of the substances is 1:5, and the addition content is 0.25g/L of the mixed additive in the total solution. The anodic oxidation is controlled under the conditions of 8 ℃ of temperature, 30min of time, 15V of working voltage and 2A/dm of current density2The cathode material is a high-purity lead plate. The schematic diagram of the prepared coated end plate without hole sealing treatment is shown in fig. 1, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
The prepared coating does not fall off or lose efficacy in the service process.
Example 4
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Cleaning the end plate for 3min at 25 ℃; using 300g/L and HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting a mixed solution of 6g/L boric acid and 30g/L sulfuric acid with a volume ratio of 1:3 as an electrolyte in anodic oxidation; adding mixed additive WCl4And isopropanol, wherein the mass ratio of the isopropanol is 1:8, and the addition content is 0.55g/L of the mixed additive in the total solution. The anodic oxidation is controlled under the conditions of 8 ℃ of temperature, 30min of time, 15V of working voltage and 2.5A/dm of current density2The cathode material is a high-purity lead plate. The schematic diagram of the prepared coated end plate without hole sealing treatment is shown in fig. 1, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
The prepared coating does not fall off or lose efficacy in the service process.
Example 5
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Cleaning the end plate for 3min at 25 ℃; adopts 300g/L HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting a mixed solution of 6g/L boric acid and 40g/L sulfuric acid with a volume ratio of 1:1 as an electrolyte in anodic oxidation; adding mixed additive ReCl3And ethanol with the mass ratio of 1:3, wherein the addition content of the mixed additive accounts for 0.3g/L of the total solution, the temperature is controlled at 8 ℃, the time is 30min, the working voltage is 15V, and the current density is 2.5A/dm2The cathode material is a high-purity lead plate. The schematic diagram of the prepared coated end plate without hole sealing treatment is shown in fig. 1, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
The prepared coating does not fall off or lose efficacy in the service process.
Example 6
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Mixed solution of (2)Cleaning the end plate at 25 deg.C for 3 min; adopts 300g/L HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting 45g/L chromic acid as electrolyte in anodic oxidation; the additive is HfOCl2And isopropanol, wherein the mass ratio of the isopropanol is 1:3, and the addition content is 0.2g/L of the mixed additive in the total solution. The anodic oxidation is controlled under the conditions of 5 ℃ of temperature, 30min of time, 15V of working voltage and 1.5A/dm of current density2The cathode material is a high-purity lead plate. The schematic diagram of the prepared coated end plate without hole sealing treatment is shown in fig. 1, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
The prepared coating does not fall off or lose efficacy in the service process.
Example 7
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Cleaning the end plate for 3min at 25 ℃; adopts 300g/L HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting a mixed solution of 6g/L boric acid and 40g/L sulfuric acid with a volume ratio of 1:1 as an electrolyte in anodic oxidation; adding mixed additive TaCl5And ethanol in a mass ratio of 1:3, wherein the addition content is mixed additionThe agent accounts for 0.6g/L of the total solution. The anodic oxidation is controlled under the conditions of 8 ℃ of temperature, 30min of time, 15V of working voltage and 2A/dm of current density2The cathode material is a high-purity lead plate. The schematic diagram of the prepared coated end plate without hole sealing treatment is shown in fig. 1, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
The prepared coating does not fall off or lose efficacy in the service process.
Example 8
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Cleaning the end plate for 3min at 25 ℃; using 300g/L and HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting a mixed solution of 6g/L boric acid and 30g/L sulfuric acid with a volume ratio of 1:3 as an electrolyte in anodic oxidation; adding mixed additive WCl4And isopropanol, wherein the mass ratio of the isopropanol is 1:12, and the addition content is 0.15g/L of the total solution after addition. The anodic oxidation is controlled under the conditions of 8 ℃ of temperature, 30min of time, 15V of working voltage and 2.5A/dm of current density2The cathode material is a high-purity lead plate. A schematic diagram of the prepared coated end plate without hole sealing treatment is shown in FIG. 1, wherein 1 is a barrier layer and 2 is a surface layerAnd 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
The prepared coating does not fall off or lose efficacy in the service process.
Example 9
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Cleaning the end plate for 3min at 25 ℃; adopts 300g/L HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting a mixed solution of 6g/L boric acid and 40g/L sulfuric acid with a volume ratio of 1:1 as an electrolyte in anodic oxidation; adding mixed additive ReCl3And ethanol with the mass ratio of 1:5, wherein the addition content of the mixed additive accounts for 0.55g/L of the total solution, the temperature is controlled at 8 ℃, the time is 30min, the working voltage is 15V, and the current density is 2.5A/dm2The cathode material is a high-purity lead plate. The schematic diagram of the prepared coated end plate without hole sealing treatment is shown in fig. 1, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
The prepared coating does not fall off or lose efficacy in the service process.
Example 10
Selecting aluminum alloy as an end plate material, cleaning the surface of the end plate by using alcohol, performing sand blasting on the surface of the end plate by using 20-mesh corundum sand under the pressure of 0.5MPa, and performing sand blasting by using 20g/L NaOH and 25g/L Na2CO3Cleaning the end plate for 3min at 25 ℃; adopts 300g/L HNO3Cleaning the end plate at 25 deg.C for 1min as acid washing agent; carrying out anodic oxidation treatment on the surface of the aluminum alloy, and adopting a mixed solution of 10g/L adipic acid and 35g/L sulfuric acid with a volume ratio of 1:1 as an electrolyte in anodic oxidation; the additive is HfOCl2And isopropanol, wherein the mass ratio of the isopropanol is 1:5, and the addition content is 0.2g/L of the mixed additive in the total solution. The anodic oxidation is controlled under the conditions of 5 ℃ of temperature, 30min of time, 15V of working voltage and 4.5A/dm of current density2The cathode material is a high-purity lead plate. The schematic diagram of the prepared coated end plate without hole sealing treatment is shown in fig. 1, wherein 1 is a barrier layer, 2 is a surface layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
And (3) sealing holes by adopting 45g/L potassium dichromate at 80 ℃ for 35min and with the pH value of 5.2. The schematic diagram of the prepared coated end plate subjected to hole sealing treatment is shown in fig. 2, wherein 1 is a barrier layer, 2 is a surface layer, 3 is a sealing layer, and 4 is an aluminum alloy end plate. Wherein the surface layer has a microporous layer therein.
The prepared coating comprises a barrier layer, a surface layer and a closed layer on the surface layer, wherein the barrier layer is positioned between the surface layer and an end plate, a microporous layer is arranged in the surface layer, the thickness of the barrier layer is 8-10 mu m, the thickness of the surface layer is 40-50 mu m, the thickness of the closed layer is 2-3 mu m, and the porosity of the coating is 3-5%.
The prepared coating does not fall off or lose efficacy in the service process.

Claims (10)

1. The preparation method of the aluminum alloy end plate coating is characterized by comprising the steps of carrying out sand blasting, cleaning, anodic oxidation and hole sealing on the aluminum alloy end plate;
the electrolyte in the anodic oxidation is 30-50 g/L chromic acid; or a mixed solution of 5-10 g/L boric acid and 30-50 g/L sulfuric acid, wherein the mixing volume ratio of the boric acid to the sulfuric acid is 1: 0.5-3; or a mixed solution of 10-25 g/L adipic acid and 30-50 g/L sulfuric acid, wherein the mixing volume ratio of the adipic acid to the sulfuric acid is 1: 1-5;
adding a mixed additive into the electrolyte, wherein the content of the mixed additive in the total solution is 0.1-3 g/L; the mixed additive is HfOCl2And isopropanol, the mass ratio of the two is 1: 3-5; or the mixed additive is TaCl5And ethanol, the mass ratio of the two is 1: 3-5; or the mixed additive is WCl4And isopropanol, the mass ratio of the two is 1: 8-12; or the mixed additive is ReCl3And ethanol, wherein the mass ratio of the ethanol to the ethanol is 1: 3-5.
2. The method according to claim 1, wherein the anodic oxidation is controlled under conditions of-5 to 15 ℃, an oxidation time of 15 to 40min, a working voltage of 15 to 25V, and a current density of 1.5 to 4.5A/dm2(ii) a And/or selecting a high-purity lead plate or a graphite plate as a cathode material; and/or cleaning the surface of the end plate by adopting alcohol before the sand blasting treatment; and/or, the sand blasting treatment is carried out by selecting 10-25 meshes of corundum sand under the air pressure of 0.5-1 MPa; and/or the mixing volume ratio of the boric acid to the sulfuric acid is 1: 1; or the mixing volume ratio of the adipic acid and the sulfuric acid is 1: 3.
3. The method of claim 2, wherein the anodization temperature is controlled5-10 ℃, the oxidation time is 15-40 min, the working voltage is 15-20V, and the current density is 1.5-4.5A/dm2。
4. The method according to claim 1 or 2, wherein 15 to 35g/L NaOH and 20 to 30g/L Na are selected for cleaning after the sand blasting treatment2CO3The mixed solution or the neutral organic solvent is used as an oil removing agent, the end plate is cleaned for 1-5 min at the temperature of 20-45 ℃, and then 300-400 g/L HNO is selected3The solution is used as a pickling agent to clean the end plate for 1-5 min at 20-25 ℃.
5. The method of claim 4, wherein the NaOH and Na2CO3The ratio of (A) to (B) is 1: 2-5.
6. The production method according to claim 1 or 2, wherein hole sealing treatment is performed after the end plate is cleaned again after anodic oxidation, and deionized water is selected for cleaning; and/or the hole sealing treatment is carried out by immersing the end plate into a potassium dichromate solution, wherein the concentration of the potassium dichromate solution in the hole sealing treatment is controlled to be 40-75 g/L, the pH value is 5-7, the temperature is 80-95 ℃, and the time is 20-45 min.
7. A coating obtained by the production method according to any one of claims 1 to 6.
8. The coating of claim 7, wherein the coating comprises a barrier layer, a surface layer, and a seal layer on the surface layer, the barrier layer being located between the surface layer and the end plate, the surface layer having a microporous layer therein, the surface layer having a thickness of 10 to 100 μm, the barrier layer having a thickness of 0.01 to 10 μm, the seal layer having a thickness of 1 to 20 μm, the coating having a porosity of 1 to 5%.
9. An aluminium alloy end plate comprising a coating according to claim 7 or 8.
10. A proton membrane fuel cell comprising the aluminum alloy end plate of claim 9.
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