Method for repairing surface coating of metal bipolar plate

文档序号：843043 发布日期：2021-04-02 浏览：56次中文

阅读说明：本技术 一种金属双极板表面涂层的修复方法 (Method for repairing surface coating of metal bipolar plate ) 是由陈果张新丰覃博文陈歌张明凯于 2020-11-17 设计创作，主要内容包括：本发明公开了一种金属双极板表面涂层的修复方法,包括：对金属双极板表面涂层的损伤区进行打磨,形成粗糙表面；对经过所述打磨后的金属双极板进行超声除油,后进行清洗和烘干；对经过所述烘干后的金属双极板的表面进行电镀,形成电镀层；其中,所述电镀层选自Cr电镀层、Ti电镀层、Ni电镀层、Zr电镀层、Nb电镀层、Au电镀层、Ag电镀层、Pt电镀层中的一种或两种以上。本发明提供的一种金属双极板表面涂层的修复方法,通过对金属双极板表面涂层的损伤区进行打磨,然后进行超声除油、清洗、烘干、电镀等一系列工艺,能够提高带涂层金属双极板的利用率,同时能够降低材料损耗和工艺成本。(The invention discloses a method for repairing a surface coating of a metal bipolar plate, which comprises the following steps: polishing the damaged area of the surface coating of the metal bipolar plate to form a rough surface; ultrasonic degreasing is carried out on the polished metal bipolar plate, and then cleaning and drying are carried out; electroplating the surface of the dried metal bipolar plate to form an electroplated layer; wherein the electroplated layer is one or more than two of Cr electroplated layer, Ti electroplated layer, Ni electroplated layer, Zr electroplated layer, Nb electroplated layer, Au electroplated layer, Ag electroplated layer and Pt electroplated layer. According to the repairing method of the surface coating of the metal bipolar plate, provided by the invention, the damaged area of the surface coating of the metal bipolar plate is polished, and then a series of processes such as ultrasonic oil removal, cleaning, drying, electroplating and the like are carried out, so that the utilization rate of the metal bipolar plate with the coating can be improved, and meanwhile, the material loss and the process cost can be reduced.)

1. A method for repairing a surface coating of a metal bipolar plate, the method comprising:

polishing the damaged area of the surface coating of the metal bipolar plate to form a rough surface;

ultrasonic degreasing is carried out on the polished metal bipolar plate, and then cleaning and drying are carried out;

electroplating the surface of the dried metal bipolar plate to form an electroplated layer;

wherein the electroplated layer is one or more than two of Cr electroplated layer, Ti electroplated layer, Ni electroplated layer, Zr electroplated layer, Nb electroplated layer, Au electroplated layer, Ag electroplated layer and Pt electroplated layer.

2. The method for repairing a surface coating of a metal bipolar plate according to claim 1, wherein the step of electroplating the surface of the dried metal bipolar plate to form an electroplated layer comprises:

in the electroplating process, the type of the electroplated layer is selected according to the type of the base material of the metal bipolar plate and the type of the material of the surface coating of the metal bipolar plate.

3. The method for repairing a surface coating of a metal bipolar plate according to claim 1, wherein the step of electroplating the surface of the dried metal bipolar plate to form an electroplated layer comprises:

if the material type of the surface coating of the metal bipolar plate is a carbon material, selecting the type of the electroplated layer according to the type of the base material of the metal bipolar plate;

if the material type of the surface coating of the metal bipolar plate is a metal material, the type of the electroplated layer is the same as the type of the metal material of the surface coating of the metal bipolar plate.

4. The method for repairing a surface coating of a metal bipolar plate according to claim 3, wherein if the material type of the surface coating of the metal bipolar plate is a carbon material, the selection of the type of the plating layer according to the type of the base material of the metal bipolar plate comprises:

if the base material of the metal bipolar plate is stainless steel, the electroplated layer is one or more than two of Cr electroplated layer, Ti electroplated layer, Ni electroplated layer, Zr electroplated layer, Nb electroplated layer, Au electroplated layer and Ag electroplated layer.

5. The method for repairing a surface coating of a metal bipolar plate according to claim 3, wherein if the material type of the surface coating of the metal bipolar plate is a carbon material, the selection of the type of the plating layer according to the type of the base material of the metal bipolar plate comprises:

if the base material of the metal bipolar plate is aluminum alloy, the electroplated layer is one or two of Cr electroplated layer and Au electroplated layer.

6. The method for repairing a surface coating of a metal bipolar plate according to claim 3, wherein if the material type of the surface coating of the metal bipolar plate is a carbon material, the selection of the type of the plating layer according to the type of the base material of the metal bipolar plate comprises:

if the base material of the metal bipolar plate is titanium alloy, the electroplated layer is one or more of a Ti electroplated layer, an Au electroplated layer and a Pt electroplated layer.

7. The method for repairing a surface coating of a metal bipolar plate according to claim 1 or 2, wherein the step of electroplating the surface of the dried metal bipolar plate to form an electroplated layer comprises: the number of the electroplated layers is 1 or more than 2;

when the number of the electroplated layers is more than 2, the thermal expansion coefficients of the adjacent electroplated layers are the same or similar.

8. The method for repairing a surface coating of a metal bipolar plate according to claim 1 or 2, wherein the step of plating the surface of the dried metal bipolar plate to form a plated layer comprises:

(1) coating a plating resistant paint on the area of the surface of the dried metal bipolar plate outside the area to be electroplated, and then preserving heat for 85-95 min at the temperature of 55-65 ℃ to form a plating resistant paint film;

(2) electroplating the area to be electroplated on the surface of the dried metal bipolar plate to form the electroplated layer;

(3) and removing the plating resistance paint film.

9. The method for repairing the surface coating of the metal bipolar plate according to claim 1 or 2, wherein the grinding time is 8-12 min;

the ultrasonic oil removal time is 5-8 min;

the cleaning time is 4-6 min;

the drying time is 8-12 min;

the electroplating time is 1-1.5 h.

10. The method for repairing the surface coating of the metal bipolar plate according to claim 1 or 2, wherein the ultrasonic degreasing of the polished metal bipolar plate comprises;

immersing the polished metal bipolar plate into an organic solution for ultrasonic degreasing;

wherein the organic solvent is selected from one or more of acetone, dichloromethane, toluene or carbon tetrachloride.

Technical Field

The invention belongs to the technical field of electrochemistry, and particularly relates to a method for repairing a surface coating of a metal bipolar plate.

Background

The metal bipolar plate, which is an important part of the fuel cell, is very susceptible to corrosion, which may seriously affect the life span of the fuel cell. In this regard, coatings are typically added to the surface of the metal bipolar plates to reduce corrosion and thereby increase the life of the fuel cell.

However, during the coating process for preparing the metal bipolar plate, defects of uneven coating coverage, excessively thin coating and incomplete coating coverage are easily generated. In addition, the coated metal bipolar plate has a problem that the coating is damaged and then falls off to expose the substrate during transportation and assembly. Both of these reasons result in unacceptable coatings for metallic bipolar plates. The repair process of incomplete or damaged coating is complex, especially the process of removing and re-depositing the coating is difficult, the cost is high, and great economic loss is brought.

Therefore, it is necessary to develop a method for repairing the surface coating of the metal bipolar plate to improve the utilization rate of the coated metal bipolar plate and reduce the material loss and the process cost.

Disclosure of Invention

In view of the above problems, the present invention provides a method for repairing a surface coating of a metal bipolar plate. According to the repairing method of the surface coating of the metal bipolar plate, provided by the invention, the damaged area of the surface coating of the metal bipolar plate is polished, and then a series of processes such as ultrasonic oil removal, cleaning, drying, electroplating and the like are carried out, so that the utilization rate of the metal bipolar plate with the coating can be improved, and meanwhile, the material loss and the process cost can be reduced.

The technical scheme of the invention for realizing the purpose is as follows:

in one aspect of the present invention, there is provided a method for repairing a surface coating of a metal bipolar plate, including:

polishing the damaged area of the surface coating of the metal bipolar plate to form a rough surface;

ultrasonic degreasing is carried out on the polished metal bipolar plate, and then cleaning and drying (for example, hot air drying) are carried out;

electroplating the surface of the dried metal bipolar plate to form an electroplated layer;

In some embodiments of the present invention, in the method for repairing a surface coating of a metal bipolar plate according to the present invention, during the polishing, when the damaged area of the surface coating of the metal bipolar plate is not large in area or the defect of the damaged area is obvious, the damaged area is slightly polished to form a rough surface (so as to improve the bonding force during the repair).

In some embodiments of the invention, in the method for repairing a surface coating of a metal bipolar plate, during the polishing, the carbon coating in the damaged area of the surface coating of the metal bipolar plate is removed, and the transition layer of the surface coating of the metal bipolar plate is polished.

In some embodiments of the present invention, in the method for repairing a surface coating of a metal bipolar plate, the kind of the plating layer may include: cr plating layer, Ti plating layer, Ni plating layer, Zr plating layer, Nb plating layer, Au plating layer, Ag plating layer, Pt plating layer.

In some embodiments of the present invention, in the method for repairing a surface coating of a metal bipolar plate according to the present invention, the substrate types of the metal bipolar plate may include: stainless steel, aluminum alloy, titanium alloy.

In some embodiments of the present invention, in the method for repairing a surface coating of a metal bipolar plate, the material types of the surface coating of the metal bipolar plate may include: carbon materials, metal materials.

In some embodiments of the present invention, in the method for repairing a surface coating of a metal bipolar plate according to the present invention, if the material type of the surface coating of the metal bipolar plate is a carbon material, the type of the plating layer is selected according to the type of the substrate of the metal bipolar plate, and the method includes:

if the base material of the metal bipolar plate is aluminum alloy, the electroplated layer is one or two of Cr electroplated layer and Au electroplated layer.

if the base material of the metal bipolar plate is titanium alloy, the electroplated layer is one or more of a Ti electroplated layer, an Au electroplated layer and a Pt electroplated layer.

when the number of the electroplated layers is more than 2, the thermal expansion coefficients of the adjacent electroplated layers are the same or similar.

In some embodiments of the present invention, when the number of the plating layers is 2 or more, the thermal expansion coefficients of adjacent plating layers are the same or similar, and may include: the electroplated metal with the same or similar thermal expansion coefficient (when the difference of the thermal expansion coefficients of the metal in the thermal expansion coefficient table is not more than 8) is selected according to the thermal expansion coefficient table of the metal material in the field.

(2) electroplating the area to be electroplated on the surface of the dried metal bipolar plate to form the electroplated layer;

(3) and removing the plating resistance paint film.

In some embodiments of the invention, in the method for repairing a surface coating of a metal bipolar plate, the polishing time is 8-12 min; the ultrasonic oil removal time is 5-8 min; the cleaning time is 4-6 min; the drying time is 8-12 min; the electroplating time is 1-1.5 h.

In some embodiments of the present invention, in the method for repairing a surface coating of a metal bipolar plate according to the present invention, the ultrasonic degreasing of the polished metal bipolar plate comprises; immersing the polished metal bipolar plate into an organic solution for ultrasonic degreasing; wherein the organic solvent is selected from one or more of acetone, dichloromethane, toluene or carbon tetrachloride.

In some embodiments of the present invention, in the method for repairing a surface coating of a metal bipolar plate according to the present invention, the step of electroplating the surface of the dried metal bipolar plate to form an electroplated layer includes: in the electroplating process, the electroplating current density on the surface of the polar plate is 1.2-2.1A/dm²。

the method for coating the plating resistant paint comprises the following steps: coating a plating resisting paint for 2 times on the surface of the dried metal bipolar plate except the area to be electroplated under the humidity of 25-80 RH (%), and then placing the metal bipolar plate in a curing tank at the temperature of 55-65 ℃ for heat preservation for 85-95 min.

One or more technical embodiments of the present invention have at least the following technical effects or advantages:

(1) according to the repairing method of the surface coating of the metal bipolar plate, provided by the invention, the damaged area of the surface coating of the metal bipolar plate is polished, and then a series of processes such as ultrasonic oil removal, cleaning, drying, electroplating and the like are carried out, so that the utilization rate of the metal bipolar plate with the coating can be improved, and meanwhile, the material loss and the process cost can be reduced.

(2) In the prior art, if the coating of the metal bipolar plate is damaged or defective, the coating needs to be completely removed and then prepared again. The process has the advantages of long process flow (more than 6 hours), large energy consumption, high cost and no environmental protection. In the repairing method of the surface coating of the metal bipolar plate, provided by the invention, one or more layers of compact metal coatings are plated on the metal bipolar plate by adopting a specific electroplating method, the metal coatings have good corrosion resistance and high conductivity, and the metal coatings and the base material of the metal bipolar plate have good bonding force, so that the energy consumption and the process time consumption are greatly reduced (only about 3 hours).

(3) The method for repairing the surface coating of the metal bipolar plate considers the binding force between the metal plating layer and the metal bipolar plate base material and the binding force between the metal plating layers in the electroplating process, considers the matching property of the thermal expansion coefficients of the metal plating layers, and selects the types of the electroplated metal plating layers in a targeted manner. The inventor conducts a large number of experiments, and selects one or more than two of Cr electroplated layer, Ti electroplated layer, Ni electroplated layer, Zr electroplated layer, Nb electroplated layer, Au electroplated layer, Ag electroplated layer and Pt electroplated layer according to the type of the base material of the metal bipolar plate and the type of the material of the surface coating of the metal bipolar plate. Thereby enhancing the conductivity, corrosion resistance and service life of the surface coating of the repaired metal bipolar plate.

(4) The method for repairing the surface coating of the metal bipolar plate does not need a high-energy-consumption and high-pollution process of electrolytic film removal and a high-cost process of vacuum film coating. The method for repairing the surface coating of the metal bipolar plate only needs to carry out an electroplating process, so that the process difficulty is reduced, and the energy consumption and the process time consumption are greatly reduced.

(5) In the method for repairing the surface coating of the metal bipolar plate, the coating is repaired by adopting an electroplating process, the coating deposition speed of the process is high, the method is favorable for rapidly repairing the damaged area of the surface coating of the metal bipolar plate in large batch, the rejection rate of products is reduced, and the method is economical and applicable.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.

Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

In order to solve the technical problems, the embodiments of the present invention provide the following general ideas:

in one aspect of the present invention, there is provided a method for repairing a surface coating of a metal bipolar plate, including:

polishing the damaged area of the surface coating of the metal bipolar plate to form a rough surface;

ultrasonic degreasing is carried out on the polished metal bipolar plate, and then cleaning and drying (for example, hot air drying) are carried out;

electroplating the surface of the dried metal bipolar plate to form an electroplated layer;

In order to overcome the defects of the surface coating repair process of the metal bipolar plate in the prior art, the inventor adopts a specific repair process through a large amount of researches, namely: the damaged area of the surface coating of the metal bipolar plate is polished, ultrasonically degreased, cleaned and dried, and then a series of processes such as electroplating are carried out by adopting specific metal, so that the utilization rate of the metal bipolar plate with the coating can be improved, and meanwhile, the material loss and the process cost can be reduced.

In the process of designing the electroplating process, the inventor considers the binding force between the metal plating layer and the metal bipolar plate base material and the binding force between the metal plating layers, considers the matching property of the thermal expansion coefficients of the metal plating layers and selects the type of the electroplated metal plating layer in a targeted manner. Therefore, the conductivity, the corrosion resistance and the service life of the surface coating of the repaired metal bipolar plate are enhanced.

In order to better achieve the purpose of the invention, the inventor adopts the specific electroplating method to form one or more layers of dense metal coatings on the metal bipolar plate, wherein the metal coatings have better corrosion resistance and higher conductivity, and the metal coatings and the base material of the metal bipolar plate have better bonding force.

The inventors have further studied plating conditions, and when the base material of the metal bipolar plate is stainless steel, the plating layer is limited to one or more selected from the group consisting of Cr plating layer, Ti plating layer, Ni plating layer, Zr plating layer, Nb plating layer, Au plating layer, and Ag plating layer, and the corrosion resistance, conductivity, and service life of the metal plating layer can be further improved.

if the base material of the metal bipolar plate is aluminum alloy, the electroplated layer is one or two of Cr electroplated layer and Au electroplated layer.

The inventors have further studied plating conditions, and when the base material of the metal bipolar plate is an aluminum alloy, the plating layer is limited to one or two selected from a Cr plating layer and an Au plating layer, and the corrosion resistance, conductivity and service life of the metal plating layer can be further improved.

if the base material of the metal bipolar plate is titanium alloy, the electroplated layer is one or more of a Ti electroplated layer, an Au electroplated layer and a Pt electroplated layer.

The inventors have further studied plating conditions, and when the base material of the metal bipolar plate is a titanium alloy, the plating layer is limited to one or more selected from a Ti plating layer, an Au plating layer, and a Pt plating layer, and the corrosion resistance, conductivity, and service life of the metal plating layer can be further improved.

(2) electroplating the area to be electroplated on the surface of the dried metal bipolar plate to form the electroplated layer;

(3) and removing the plating resistance paint film.

The invention adopts the electroplating process to replace the vacuum coating again to repair the coating of the metal bipolar plate without the processes of high energy consumption, high pollution and high cost of electrolytic film removal. Therefore, the process difficulty of the repair method of the surface coating of the metal bipolar plate is reduced, the energy consumption and the process time consumption are greatly reduced, the repair cost of the metal bipolar plate can be reduced by 50-70%, and the repair efficiency of the coating can be improved.

The following will describe in detail the repairing method of the surface coating of the metal bipolar plate described in the present application with reference to examples, comparative examples and experimental data.

Example 1:

(1) in this embodiment, the metal bipolar plate is made of stainless steel, and the surface coating of the metal bipolar plate is made of a metal coating of Cr or a Cr compound.

(2) Firstly, finding out unqualified areas (damaged areas) such as damaged or exposed surfaces of the surface coatings of the metal bipolar plates, and marking the areas by using a marking pen. The damaged area is then sanded with a sander to remove the surface coating and to polish to the transition layer. And slightly polishing the exposed bottom area without the coating until the surface is rough. After polishing was completed (polishing was carried out for 8min), a rough surface was formed. Ultrasonic degreasing (ultrasonic degreasing in acetone for 5min), cleaning for 4min, and drying for 8min (drying temperature is 55 ℃) are carried out on the polished metal bipolar plate. Coating a plating resistant paint on the area of the surface of the dried metal bipolar plate outside the area to be electroplated under the humidity of 25RH (%), coating for 2 times, and then preserving heat for 85min at the temperature of 55 ℃ to form a plating resistant paint film.

(3) Electroplating the area to be electroplated on the surface of the dried metal bipolar plate (electroplating current density is 1.2A/dm)²) Forming the electroplated layer, specifically comprising: firstly plating a layer of Ni on the surface of the metal bipolar plate as a substrate electroplated layer, and then plating a layer of Cr, thus being beneficial to increasing the binding force of the electroplated layer. The whole electroplating process is 1 h. When the number of the electroplated layers is more than 2, the thermal expansion coefficients of the adjacent electroplated layers are the same or similar. Selecting electroplated metal with the same or similar thermal expansion coefficient according to a thermal expansion coefficient table of metal materials in the field; when the difference of the thermal expansion coefficients of the metals in the thermal expansion coefficient table is not more than 8.

(4) And removing the plating resistance paint film after the electroplating is finished.

(5) And (4) the formed electroplated layer is qualified through inspection, and the repair of the surface coating of the metal bipolar plate is completed.

Example 2:

(1) in this embodiment, the metal bipolar plate is made of stainless steel, and the surface coating of the metal bipolar plate is made of a carbon material.

(2) Firstly, finding out unqualified areas (damaged areas) such as damaged or exposed surfaces of the surface coatings of the metal bipolar plates, and marking the areas by using a marking pen. The damaged area is then sanded with a sander to remove the surface coating and to polish to the transition layer. And slightly polishing the exposed bottom area without the coating until the surface is rough. After finishing (grinding for 12min), a rough surface is formed. Ultrasonic degreasing is carried out on the polished metal bipolar plate (ultrasonic degreasing is carried out in dichloromethane for 8min), cleaning is carried out for 6min, and drying is carried out for 12min (the drying temperature is 65 ℃). Coating a plating resistant paint on the area of the surface of the dried metal bipolar plate outside the area to be electroplated under the humidity of 80RH (%), and then preserving heat for 95min at the temperature of 65 ℃ to form a plating resistant paint film.

(3) Electroplating the area to be electroplated on the surface of the dried metal bipolar plate (electroplating current density is 2.1A/dm)²) Forming the electroplated layer, specifically comprising: firstly, a layer of Ni is electroplated on the surface of the metal bipolar plate to be used as a substrate electroplated layer, and then a layer of Zr is electroplated, so that the bonding force of the electroplated layer is increased. The whole electroplating process is 1.5 h. When the number of the electroplated layers is more than 2, the thermal expansion coefficients of the adjacent electroplated layers are the same or similar. Selecting electroplated metal with the same or similar thermal expansion coefficient according to a thermal expansion coefficient table of metal materials in the field; when the difference of the thermal expansion coefficients of the metals in the thermal expansion coefficient table is not more than 8.

(4) And removing the plating resistance paint film after the electroplating is finished.

(5) And (4) the formed electroplated layer is qualified through inspection, and the repair of the surface coating of the metal bipolar plate is completed.

Example 3:

(1) in this embodiment, the base material of the metal bipolar plate is aluminum alloy, and the material of the surface coating of the metal bipolar plate is Cr or a Cr compound.

(2) Firstly, finding out unqualified areas (damaged areas) such as damaged or exposed surfaces of the surface coatings of the metal bipolar plates, and marking the areas by using a marking pen. The damaged area is then sanded with a sander to remove the surface coating and to polish to the transition layer. And slightly polishing the exposed bottom area without the coating until the surface is rough. After polishing was completed (polishing was carried out for 10min), a rough surface was formed. Ultrasonic degreasing (ultrasonic degreasing in toluene for 6min), cleaning for 5min, and drying for 10min (drying temperature is 60 ℃) are carried out on the polished metal bipolar plate. Coating a plating resistant paint on the area of the surface of the dried metal bipolar plate outside the area to be electroplated under the humidity of 25RH (%), and then preserving heat for 90min at the temperature of 60 ℃ to form a plating resistant paint film.

(4) And removing the plating resistance paint film after the electroplating is finished.

(5) And (4) the formed electroplated layer is qualified through inspection, and the repair of the surface coating of the metal bipolar plate is completed.

Example 4:

(1) in this embodiment, the base material of the metal bipolar plate is an aluminum alloy, and the material of the surface coating of the metal bipolar plate is a carbon material.

(2) Firstly, finding out unqualified areas (damaged areas) such as damaged or exposed surfaces of the surface coatings of the metal bipolar plates, and marking the areas by using a marking pen. The damaged area is then sanded with a sander to remove the surface coating and to polish to the transition layer. And slightly polishing the exposed bottom area without the coating until the surface is rough. After polishing was completed (polishing for 9min), a rough surface was formed. Ultrasonic degreasing (ultrasonic degreasing in carbon tetrachloride for 8min), cleaning for 6min, and drying for 10min (drying temperature is 55 ℃) are carried out on the polished metal bipolar plate. Coating a plating resistant paint on the area of the surface of the dried metal bipolar plate outside the area to be electroplated under the humidity of 55RH (%), coating for 2 times, and then preserving heat for 90min at the temperature of 60 ℃ to form a plating resistant paint film.

(3) Electroplating the area to be electroplated on the surface of the dried metal bipolar plate (electroplating current density is 2A/dm)²) Forming the electroplated layer, specifically comprising: and electroplating a layer of Cr on the surface of the metal bipolar plate. The whole electroplating process is 1 h.

(4) And removing the plating resistance paint film after the electroplating is finished.

(5) And (4) the formed electroplated layer is qualified through inspection, and the repair of the surface coating of the metal bipolar plate is completed.Example 5:

(1) in this embodiment, the base material of the metal bipolar plate is a titanium alloy, and the material of the surface coating of the metal bipolar plate is Ti or a Ti compound.

(2) Firstly, finding out unqualified areas (damaged areas) such as damaged or exposed surfaces of the surface coatings of the metal bipolar plates, and marking the areas by using a marking pen. The damaged area is then sanded with a sander to remove the surface coating and to polish to the transition layer. And slightly polishing the exposed bottom area without the coating until the surface is rough. After polishing was completed (polishing was carried out for 11min), a rough surface was formed. Ultrasonic degreasing (ultrasonic degreasing in carbon tetrachloride for 8min), cleaning for 6min, and drying for 8min (drying temperature is 65 ℃) are carried out on the polished metal bipolar plate. Coating a plating resistant paint on the area of the surface of the dried metal bipolar plate except the area to be electroplated under the humidity of 29RH (%), and then preserving heat for 85min at the temperature of 65 ℃ to form a plating resistant paint film.

(3) Electroplating the area to be electroplated on the surface of the dried metal bipolar plate (electroplating current density is 1.5A/dm)²) Forming the electroplated layer, specifically comprising: and electroplating a layer of Ti on the surface of the metal bipolar plate. The whole electroplating process is 1 h.

(4) And removing the plating resistance paint film after the electroplating is finished.

(5) And (4) the formed electroplated layer is qualified through inspection, and the repair of the surface coating of the metal bipolar plate is completed.

Example 6:

(1) in this embodiment, the base material of the metal bipolar plate is a titanium alloy, and the material of the surface coating of the metal bipolar plate is a carbon material.

(2) Firstly, finding out unqualified areas (damaged areas) such as damaged or exposed surfaces of the surface coatings of the metal bipolar plates, and marking the areas by using a marking pen. The damaged area is then sanded with a sander to remove the surface coating and to polish to the transition layer. And slightly polishing the exposed bottom area without the coating until the surface is rough. After polishing was completed (polishing was carried out for 10min), a rough surface was formed. Ultrasonic degreasing is carried out on the polished metal bipolar plate (ultrasonic degreasing is carried out in dichloromethane for 6min), cleaning is carried out for 5min, and drying is carried out for 10min (the drying temperature is 55 ℃). Coating a plating resistant paint on the area of the surface of the dried metal bipolar plate except the area to be electroplated under the humidity of 36RH (%), and then preserving heat for 90min at the temperature of 60 ℃ to form a plating resistant paint film.

(4) And removing the plating resistance paint film after the electroplating is finished.

(5) And (4) the formed electroplated layer is qualified through inspection, and the repair of the surface coating of the metal bipolar plate is completed.

Example 7:

(1) in this embodiment, the metal bipolar plate is made of stainless steel, and the surface coating of the metal bipolar plate is made of a carbon material.

(2) Firstly, finding out unqualified areas (damaged areas) such as damaged or exposed surfaces of the surface coatings of the metal bipolar plates, and marking the areas by using a marking pen. The damaged area is then sanded with a sander to remove the surface coating and to polish to the transition layer. And slightly polishing the exposed bottom area without the coating until the surface is rough. After polishing was completed (polishing was carried out for 10min), a rough surface was formed. Ultrasonic degreasing is carried out on the polished metal bipolar plate (ultrasonic degreasing is carried out in dichloromethane for 8min), cleaning is carried out for 6min, and drying is carried out for 8min (the drying temperature is 55 ℃). Coating a plating resistant paint on the area of the surface of the dried metal bipolar plate outside the area to be electroplated under the humidity of 75RH (%), and then preserving heat for 90min at the temperature of 65 ℃ to form a plating resistant paint film.

(4) And removing the plating resistance paint film after the electroplating is finished.

(5) And (4) the formed electroplated layer is qualified through inspection, and the repair of the surface coating of the metal bipolar plate is completed.Example 8:

(1) in this embodiment, the base material of the metal bipolar plate is an aluminum alloy, and the material of the surface coating of the metal bipolar plate is a carbon material.

(2) Firstly, finding out unqualified areas (damaged areas) such as damaged or exposed surfaces of the surface coatings of the metal bipolar plates, and marking the areas by using a marking pen. The damaged area is then sanded with a sander to remove the surface coating and to polish to the transition layer. And slightly polishing the exposed bottom area without the coating until the surface is rough. After polishing was completed (polishing for 9min), a rough surface was formed. Ultrasonic degreasing is carried out on the polished metal bipolar plate (ultrasonic degreasing is carried out in dichloromethane for 7min), cleaning is carried out for 5min, and drying is carried out for 10min (the drying temperature is 55 ℃). Coating a plating resistant paint on the area of the surface of the dried metal bipolar plate outside the area to be electroplated under the humidity of 25RH (%), and then preserving heat for 90min at the temperature of 60 ℃ to form a plating resistant paint film.

(4) And removing the plating resistance paint film after the electroplating is finished.

(5) And (4) the formed electroplated layer is qualified through inspection, and the repair of the surface coating of the metal bipolar plate is completed.

From the above examples it can be seen that: compared with the prior art (the coating of the metal bipolar plate is damaged or has defects, the coating needs to be completely removed and then prepared again, the process flow is long (more than 6 hours), the energy consumption is high, the cost is high, and the process is not environment-friendly), the method for repairing the surface coating of the metal bipolar plate provided by the invention does not need a high-energy consumption and high-pollution process of electrolytic film removal, and does not need a high-cost process of vacuum film coating. The method for repairing the surface coating of the metal bipolar plate only needs to carry out an electroplating process, so that the process difficulty is reduced, and the energy consumption and the process time consumption (only about 3 hours) are greatly reduced. The invention adopts a specific electroplating method to plate one or more layers of compact metal coatings on the metal bipolar plate, the metal coatings have good corrosion resistance and high conductivity, and the metal coatings and the base material of the metal bipolar plate have good binding force.

Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

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Method for repairing surface coating of metal bipolar plate

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