CN115051009A - Y-doped Co-Mn spinel coating, and preparation method and application thereof - Google Patents

Abstract

The invention discloses a Y-doped Co-Mn spinel coating, a preparation method and application thereof, and belongs to the technical field of surface coating material preparation. The preparation method of the Y-doped Co-Mn spinel coating includes the following steps: step 1: pretreatment; step 2: preparing a Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating; step 3: Preparation of Y-doped Co-Mn spinel coatings. The invention also discloses the Y-doped Co-Mn spinel coating prepared by the above preparation method and its application. By adopting the method of the invention, the prepared ferritic stainless steel surface protective coating is smoother and denser, more firmly combined with the substrate, better in wrapping and plating, and has excellent Cr resistance and good electrical conductivity.

Description

A kind of Y-doped Co-Mn spinel coating, its preparation method and application

technical field

The invention relates to a Y-doped Co-Mn spinel coating, a preparation method and application thereof, and belongs to the technical field of surface coating material preparation.

Background technique

Solid oxide fuel cells have the advantages of high cleanliness, modularity, high energy conversion efficiency, high specific power and power density, and have broad application prospects. A single solid oxide fuel cell (Solid Oxide Fuel Cell, SOFC for short) is mainly composed of a cathode, an anode and an electrolyte. The connector in the stack mainly plays the role of supporting and connecting single cells, conducting current and isolating fuel gas. With the development of SOFC working temperature to medium temperature (600℃-800℃), ferritic stainless steel (FSS) has become the most ideal due to its good electrical and thermal conductivity, low cost and good processing performance. One of the SOFC connector materials. However, under the working environment of SOFC, the surface of FSS is easily oxidized, and the resulting oxide film will increase the contact resistance of the battery stack. The electrical properties are seriously attenuated, and even lead to the failure of the battery stack, which seriously restricts the commercial development and application of SOFCs. In order to solve this problem, the most effective method is to coat a layer of spinel protective coating on the surface of FSS to improve the problems of insufficient antioxidant capacity and Cr volatilization during FSS work, and to improve the service performance of SOFC cells.

The commonly used preparation method of spinel coating on FSS surface has disadvantages such as expensive equipment, complex process, poor wrapping property, difficult to control and uneven coating thickness, easy generation of pores and cracks on the surface, etc. It is difficult to adapt to complex connector shapes, cost higher, and the bonding strength between the prepared coating and the substrate needs to be further improved.

In view of this, it is necessary to provide a new preparation method of ferritic stainless steel surface protective coating to overcome the deficiencies of the prior art.

SUMMARY OF THE INVENTION

One of the objectives of the present invention is to provide a preparation method of a Y-doped Co-Mn spinel coating.

The technical scheme of the present invention to solve the above-mentioned technical problems is as follows: a preparation method of Y-doped Co-Mn spinel coating, comprising the following steps:

Step 1: Preprocessing

A ferritic stainless steel substrate is provided. After grinding, it is first soaked in NaOH solution, taken out, cleaned, then soaked in H ₂ SO ₄ solution, taken out, cleaned, and then subjected to electrolytic corrosion treatment to obtain a pretreated substrate;

Step 2: Preparation of Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating

The pretreated substrate obtained in step 1 is used as the cathode, and the double cobalt plate is used as the double anode, which is placed in the deposition solution, and direct current is applied to deposit the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating; wherein , the deposition solution contains 80g/L-160g/L Mn ₃ O ₄ , 5g/L-15g/L Y ₂ O ₃ , 300g/L CoSO ₄ ·7H ₂ O, 50g/L CoCl _2. 6H ₂ O, 15g/L H ₃ BO ₃ , 10g/L sodium gluconate and 0.03g/L sodium lauryl sulfate, pH 3-5;

Step 3: Preparation of Y-doped Co-Mn spinel coating

The Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating obtained in step 2 is converted into a Y-doped Co-Mn spinel coating through heat treatment.

The principle of the present invention is:

In the present invention, the ferritic stainless steel substrate is pretreated to increase the bonding force between the subsequent coating and the ferritic stainless steel substrate; and then Co-Y ₂ O ₃ - is prepared on the surface of the pretreated substrate by a composite electrodeposition method. Mn ₃ O ₄ composite precursor coating makes Mn element and rare earth element Y embedded in the deposited Co matrix under the action of multi-field coupling; finally, the composite precursor layer is uniformly transformed by heat treatment to obtain Y-doped Co-Mn spinel Stone coating.

The preparation method of the Y-doped Co-Mn spinel coating of the present invention adopts the combination of composite electrodeposition and heat treatment conversion, and has the advantages of simple process, low cost, firm and uniform coating, good wrapping property and the like. The existing preparation method has the disadvantages of long process, difficulty in adapting to complex connector shapes, poor coating performance and high manufacturing cost, which is of great significance to the development and preparation of spinel protective coatings on ferritic stainless steel surfaces.

The beneficial effects of the present invention are:

1. By adopting the method of the present invention, the surface protective coating of the ferritic stainless steel prepared is smoother and denser, more firmly combined with the substrate, better wrapping and plating, and has excellent Cr resistance and good electrical conductivity.

2. The preparation method of the present invention only needs a voltage of 1-5V, the equipment is simple, the technological process is short, the operation is simple, the cost is low, the market prospect is broad, and it is suitable for large-scale popularization and application.

On the basis of the above technical solutions, the present invention can also be improved as follows.

Further, in step 1, the type of the ferritic stainless steel is any one of SUS430, E-brite and Crofer22.

The above-mentioned further beneficial effects are: the above-mentioned ferritic stainless steel has good electrical and thermal conductivity, thermal fatigue resistance, excellent oxidation resistance and cold working performance, and is suitable as a matrix for the subsequent preparation of Y-doped Co-Mn spinel Stone coating.

Further, in step 1, the grinding refers to grinding the ferritic stainless steel substrate with 200-mesh, 400-mesh, and 800-mesh sandpapers in sequence.

The further beneficial effect of adopting the above is that impurities and stains on the surface of the substrate can be removed.

Further, in step 1, the soaking time is 10 min, the concentration of the NaOH solution and the H ₂ SO ₄ solution are both 1 mol/L, and deionized water is used for the cleaning.

A further beneficial effect of adopting the above is to avoid passivation of the substrate and activate it.

Further, in step 1, the electrolytic corrosion treatment refers to placing the cleaned substrate in an electrolytic corrosion solution, and etched for 5 min at room temperature, wherein the electrolytic corrosion solution contains 50 g/L of CoCl ₂ ·6H ₂ O and 1 mol/L HCl, pH 5.

The further beneficial effects of adopting the above are: by adopting the above operation, the electrolytic corrosion of the substrate can be realized, and the bonding force between the subsequent coating and the substrate can be enhanced.

Further, in step 2, the distance between the cathode and the double anode in the deposition solution is both 35 mm and arranged in an equilateral triangle.

The further beneficial effects of adopting the above are: the efficiency of composite electrodeposition can be ensured, and the influence of stirring on the uniformity of the coating can be reduced.

Further, in step 2, the current density of the direct current is 10mA/cm ² -30mA/cm ² , and the applied voltage is 1V-5V.

The further beneficial effects of adopting the above are: using the above parameters, the required equipment cost is low, and the deposition effect is better.

Further, in step 2, the electromagnetic stirring rate used in the deposition is 700r/min-900r/min, and the time is 10min-20min.

The further beneficial effects of adopting the above are: adopting the above parameters, the coating is more uniform, the thickness is moderate, and the Mn content is high.

Further, in step 3, the heat treatment conversion temperature is 800° C., the heating rate is 1° C./min-5° C./min, and the heat treatment conversion time is 60 min.

The further beneficial effects of using the above are: using the above parameters, the composite precursor layer can be completely converted into a single-phase spinel coating, and the coating is not easy to crack and peel off.

The second object of the present invention is to provide a Y-doped Co-Mn spinel protective coating.

The technical solution of the present invention to solve the above technical problems is as follows: a Y-doped Co-Mn spinel coating prepared by the above preparation method.

The beneficial effects of the Y-doped Co-Mn spinel coating of the present invention are:

The Y-doped Co-Mn spinel coating of the present invention is prepared by the above preparation method, and the spinel coating is firmly bonded to the substrate, has good electrical and thermal conductivity, and has strong Cr resistance.

The third object of the present invention is to provide the application of the above-mentioned Y-doped Co-Mn spinel coating.

The technical solutions of the present invention to solve the above technical problems are as follows: the application of the Y-doped Co-Mn spinel coating prepared by the above preparation method as a protective coating for a SOFC connector material.

The beneficial effects of the application of the present invention are:

The Y-doped Co-Mn spinel coating of the present invention can be used as a protective coating for the SOFC connector material, greatly improves the Cr resistance and electrical conductivity of the FSS connector material, is easy to realize mass production, and has broad application prospects .

Description of drawings

FIG. 1 is a SEM image of the surface of the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite pilot coating in Example 1 of the present invention.

FIG. 2 is a SEM image of the surface of the Y-doped Co-Mn spinel coating in Example 1 of the present invention.

FIG. 3 is the EDS composition distribution on the surface of the Y-doped Co-Mn spinel coating in Example 1 of the present invention.

FIG. 4 is a SEM image of the surface of the Y-doped Co-Mn spinel coating in Example 1 of the present invention, which is oxidized at 800° C. for 7 days.

FIG. 5 is the EDS composition distribution on the surface of the Y-doped Co-Mn spinel coating in Example 1 of the present invention, which is oxidized at 800° C. for 7 days.

FIG. 6 is an SEM image of the surface of the SUS430 substrate oxidized at 800° C. for 7 days in Example 1 of the present invention.

FIG. 7 is the distribution of EDS components on the surface of the SUS430 substrate oxidized at 800° C. for 7 days in Example 1 of the present invention.

FIG. 8 is a cross-sectional SEM image of the Y-doped Co-Mn spinel coating in Example 1 of the present invention, which is oxidized at 800° C. for 7 days.

Detailed ways

The principles and features of the present invention will be described below with reference to the specific drawings. The examples are only used to explain the present invention, but not to limit the scope of the present invention.

Example 1:

The preparation method of the Y-doped Co-Mn spinel coating of the present embodiment includes the following steps:

Step 1: Preprocessing

Provide a SUS430 ferritic stainless steel substrate with a size of 20mm x 15mm x 2mm. After grinding the ferritic stainless steel substrate with 200-mesh, 400-mesh and 800-mesh sandpaper in turn, soak it in a NaOH solution with a concentration of 1 mol/L. After taking out, ultrasonically cleaned with deionized water, then immersed in H ₂ SO ₄ solution with a concentration of 1 mol/L for 10 minutes, taken out and ultrasonically cleaned with deionized water, and then placed in electrolytic corrosion solution, at room temperature, electrolyzed Corrosion treatment was carried out for 5 minutes, wherein the electrolytic corrosion solution contained 50 g/L of CoCl ₂ ·6H ₂ O and 1 mol/L of HCl, and the pH value was 5 to obtain a pretreated substrate.

Step 2: Preparation of Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating

The pretreated substrate obtained in step 1 is used as the cathode, and the double cobalt plate is used as the double anode, which is placed in the deposition solution. The distance between the cathode and the double anode in the deposition solution is both 35 mm and arranged in an equilateral triangle. The deposition solution contains 120g/L Mn ₃ O ₄ , 10g/L Y ₂ O ₃ , 300g/L CoSO ₄ ·7H ₂ O, 50g/L CoCl ₂ ·6H ₂ O, 15g/L of H ₃ BO ₃ , 10 g/L of sodium gluconate and 0.03 g/L of sodium dodecyl sulfate, the pH value is 5.

Direct current was applied, the current density was 20mA/cm ² , and the voltage was less than 2V; the electromagnetic stirring rate was 900 r/min and the deposition time was 15 min to obtain the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating.

Step 3: Preparation of Y-doped Co-Mn spinel coating

Heat treatment of the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating obtained in step 2 at a temperature of 800° C., a heating rate of 1° C./min, and a time of 60 min, that is, the Y-doped Co-Mn tip is converted into a Y-doped Co-Mn tip. Spar coating.

This embodiment also provides the Y-doped Co-Mn spinel coating prepared by the above preparation method.

This embodiment also provides the application of the Y-doped Co-Mn spinel coating prepared by the above preparation method as a protective coating for a SOFC connector material.

FIG. 1 is a SEM image of the surface of the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite pilot coating in Example 1 of the present invention. It can be seen from the figure that under the given process parameters in Example 1, the particles of Y ₂ O ₃ and Mn ₃ O ₄ are uniformly embedded and spread in the Co matrix, forming a Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor layer.

Fig. 2 is the SEM image of the surface of the Y-doped Co-Mn spinel coating in Example 1 of the present invention, and Fig. 3 is the EDS composition analysis of the surface of the Y-doped Co-Mn spinel coating in Example 1 of the present invention . It can be seen from Fig. 2 and Fig. 3 that the surface of the Y-doped Co-Mn spinel coating prepared by the method of the present invention is uniform and dense without obvious defects, which can effectively inhibit the outward volatilization of Cr compounds. And the experiment shows that all the surface coatings of the substrate are uniform and dense, indicating that the method has good wrapping performance.

FIG. 4 is a SEM image of the surface of the Y-doped Co-Mn spinel coating in Example 1 of the present invention after being oxidized at 800°C for 7 days, and FIG. 5 is a Y-doped Co-Mn spinel coating 800 in Example 1 of the present invention. The distribution of EDS components on the surface after 7 days of oxidation at °C. It can be seen from Figure 4 and Figure 5 that after 7 days of oxidation at 800 °C, the surface grains of the Y-doped Co-Mn spinel coating are relatively uniform, flat and dense, and this structure is conducive to maintaining good contact between the coating and the electrode. And maintain the stability of SOFC performance, and the existence of Cr element is not detected on the surface of the coating, indicating that the coating still has good performance of preventing Cr volatilization after being oxidized at high temperature for a long time.

Figure 6 is the SEM image of the surface of the SUS430 substrate oxidized at 800°C for 7 days in Example 1 of the present invention, and Figure 7 is the distribution of EDS components on the surface of the SUS430 substrate oxidized at 800°C for 7 days in Example 1 of the present invention. It can be seen from Figure 6 and Figure 7 that after 7 days of oxidation at 800 °C, the grains on the surface of the SUS430 ferritic stainless steel substrate appear agglomerated, the size and distribution are uneven, the surface is extremely uneven, the bonding between grains is relatively loose, and the oxidation rate is relatively high. The high content of Cr element on the surface indicates that the volatilization of Cr element is serious, which will cause the decrease of the electrical conductivity of the SOFC connector and the battery stack.

8 is a cross-sectional SEM image of the Y-doped Co-Mn spinel coating prepared in Example 1 of the present invention after being oxidized at 800° C. for 7 days. It can be seen from the figure that the spinel coating is well combined with the substrate without cracking and spalling. The thickness of the Cr oxide layer at the junction of the substrate and the spinel coating is about 2 μm, and the thickness of the coating is about 20 μm, indicating that the oxidation rate of the substrate coated with the Y-doped Co-Mn spinel coating is low, and the prepared coating has a low oxidation rate. The layer has excellent anti-oxidative properties.

The sample with Y-doped Co-Mn spinel coating on the surface prepared in Example 1 was oxidized at 800 °C for 7 days, and tested by the four-probe method, and the surface specific resistance was 13.07 mΩ·cm ² , which was far It is smaller than the surface specific resistance of the substrate by 32.15mΩ·cm ² , and the experimental results show that the thickness of the oxide layer and the surface specific resistance have become stable at this time, and the prepared protective coating has good resistance to Cr, oxidation resistance and electrical conductivity. It can meet the requirements of SOFC connectors.

Example 2:

The preparation method of the Y-doped Co-Mn spinel coating of the present embodiment includes the following steps:

Step 1: Preprocessing

Provide E-brite ferritic stainless steel substrate with a size of 20mm × 15mm × 2mm. After grinding the ferritic stainless steel substrate with 200-mesh, 400-mesh and 800-mesh sandpaper in turn, soak it in 1mol/L NaOH solution for 10 min, take out and ultrasonically clean with deionized water, then soak in H ₂ SO ₄ solution with a concentration of 1 mol/L for 10 min, take out and ultrasonically clean with deionized water, and then place in electrolytic corrosion solution at room temperature , electrolytic corrosion treatment for 5min, wherein, the electrolytic corrosion solution contains 50g/L of CoCl ₂ ·6H ₂ O and 1mol/L of HCl, pH value is 5, and the pretreated substrate is obtained.

Step 2: Preparation of Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating

The pretreated substrate obtained in step 1 is used as the cathode, and the double cobalt plate is used as the double anode, which is placed in the deposition solution. The distance between the cathode and the double anode in the deposition solution is both 35 mm and arranged in an equilateral triangle. The deposition solution contains 120g/L Mn ₃ O ₄ , 15g/L Y ₂ O ₃ , 300g/L CoSO ₄ ·7H ₂ O, 50g/L CoCl ₂ ·6H ₂ O, 15g/L of H ₃ BO ₃ , 10 g/L of sodium gluconate and 0.03 g/L of sodium dodecyl sulfate, pH 4.

Direct current was applied, the current density of the direct current was 30mA/cm ² , and the voltage was less than 5V; the electromagnetic stirring rate was 700 r/min, and the deposition time was 5 min to obtain the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating.

Step 3: Preparation of Y-doped Co-Mn spinel coating

Heat treatment of the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating obtained in step 2 at a temperature of 800° C., a heating rate of 5° C./min, and a time of 60 minutes, that is, the Y-doped Co-Mn tip is converted into a Y-doped Co-Mn tip. Spar coating.

Using this example, compared with Example 1, a Y-doped Co-Mn spinel coating with good bonding to the substrate and good performance can also be obtained. It is only that when the deposition in step 2 is carried out, when the stirring rate is low, the uniformity and flatness of the coating surface are slightly reduced; the deposition time is short, and the coating is slightly thinner.

This embodiment also provides the Y-doped Co-Mn spinel coating prepared by the above preparation method.

This embodiment also provides the application of the Y-doped Co-Mn spinel coating prepared by the above preparation method as a protective coating for a SOFC connector material.

Example 3:

The preparation method of the Y-doped Co-Mn spinel coating of the present embodiment includes the following steps:

Step 1: Preprocessing

Provide a Crofer22 ferritic stainless steel base with a size of 20mm × 15mm × 2mm. After grinding the ferritic stainless steel base with 200-mesh, 400-mesh and 800-mesh sandpaper in turn, soak it in a NaOH solution with a concentration of 1 mol/L. After taking out, ultrasonically cleaned with deionized water, then immersed in H ₂ SO ₄ solution with a concentration of 1 mol/L for 10 minutes, taken out and ultrasonically cleaned with deionized water, and then placed in electrolytic corrosion solution, at room temperature, electrolyzed Corrosion treatment was carried out for 5 minutes, wherein the electrolytic corrosion solution contained 50 g/L of CoCl ₂ ·6H ₂ O and 1 mol/L of HCl, and the pH value was 5 to obtain a pretreated substrate.

Step 2: Preparation of Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating

The pretreated substrate obtained in step 1 was used as the cathode, and the double cobalt plate was used as the double anode, which was placed in the deposition solution. The deposition solution contains 120g/L Mn ₃ O ₄ , 15g/L Y ₂ O ₃ , 300g/L CoSO ₄ ·7H ₂ O, 50g/L CoCl ₂ ·6H ₂ O, 15g/L of H ₃ BO ₃ , 10 g/L of sodium gluconate and 0.03 g/L of sodium dodecyl sulfate, pH 4.

Direct current was applied, the current density of the direct current was 10mA/cm ² , the voltage was less than 2V, the electromagnetic stirring rate was 800 r/min, and the deposition time was 15 min to obtain the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating.

Step 3: Preparation of Y-doped Co-Mn spinel coating

Heat treatment of the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating obtained in step 2 at a temperature of 800 ° C, a heating rate of 5 ° C/min, and a time of 60 min, that is, the Y-doped Co-Mn tip is converted into a Y-doped Co-Mn tip. Spar coating.

Using this example, compared with Example 1, a Y-doped Co-Mn spinel coating with good bonding to the substrate and good performance can also be obtained. It is only that the heating rate of the heat treatment in step 3 is relatively high, and the cracking tendency of the coating surface increases. Therefore, the heating rate should not exceed 5 °C/min.

This embodiment also provides the Y-doped Co-Mn spinel coating prepared by the above preparation method.

This embodiment also provides the application of the Y-doped Co-Mn spinel coating prepared by the above preparation method as a protective coating for a SOFC connector material.

Comparative Example 1

The materials and process parameters of this comparative example are the same as those of Example 1, except that the matrix is not pretreated, the obtained composite precursor coating is poorly bonded to the matrix, the Mn content in the coating is small, and the coating is uneven.

Comparative Example 2

The materials and test procedures of this comparative example are the same as those in Example 1, the difference is that in step 2, the current density is 5 mA/cm ² and 40 mA/cm ² respectively, when the current density is 5 mA/cm ² , the obtained composite precursor The coating is not uniform and cannot cover the surface of the substrate well; when the current density is 40 mA/cm ² , the current is too large, the distribution of the composite precursor coating is not uniform, and the deposition efficiency is low.

Comparative Example 3

The materials and test procedures of this comparative example are the same as those of Example 1, except that the pH values of the deposition solution in Step 2 are 2 and 6. When pH=2, the composite precursor coating is not uniform and cannot cover the surface of the substrate well. ; When pH=6, the coating has more bubbles and the deposition efficiency is low.

Comparative Example 4

The materials and test procedures of this comparative example are the same as those of Example 1, the difference is that in Step 2, the stirring rate is 500 r/min and 1000 r/min. When the stirring rate is 500 r/min, it is difficult for the magnet to rotate, and the composite precursor coating The layer is not uniform; when 1000r/min, the coating is not uniform, the deposition efficiency is low, and the Mn content is low.

Comparative Example 5

The materials and test procedures of this comparative example are the same as those of Example 1, the difference is that the deposition time in Step 2 is 30 min. At this time, the Y-doped Co-Mn spinel coating is too thick, which is easy to cause oxidation and fall off and reduce the conductivity. performance.

Comparative Example 6

The materials and test procedures of this comparative example are the same as those of Example 1, the difference is that the heat treatment conversion temperature in No. 3 is 600°C and 700°C, at this time, the composite precursor coating cannot be completely converted into a single-phase spinel coating layer, the coating has poor Cr resistance and unevenness.

Comparative Example 7

The materials and test procedures of this comparative example are the same as those in Example 1, except that the heat treatment conversion time in step 3 is 30 min, and the composite precursor coating is not completely converted into single-phase Y-doped Co-Mn spinel. The coating affects the Cr resistance and electrical conductivity of the coating.

Comparative Example 8

The materials and test procedures of this comparative example are the same as those of Example 1, the difference is that in step 3, the heating rate of heat treatment conversion is 10°C/min. At this time, when the composite precursor coating is converted into a spinel coating, cracking and cracking are likely to occur. shedding phenomenon.

Comparative Example 9

The process parameters and test steps of this comparative example are the same as those of Example 1, the difference is that in step 2, the Mn ₃ O ₄ content of the deposition solution is 60 g/L and 200 g/L. When the content of Mn ₃ O ₄ is 60 g/L, the content of Mn in the composite precursor coating and spinel coating is less; when the content of Mn ₃ O ₄ is 200 g/L, the content of Mn and conductivity have little change.

Comparative Example 10

The process parameters and test steps of this comparative example are the same as those of Example 1, the difference is that in step 2, the Y ₂ O ₃ content of the deposition solution is 2 g/L and 20 g/L. When the content of Y ₂ O ₃ is 2g/L, the combination of the coating and the substrate is not strong; when the content of Y ₂ O ₃ is 20 g/L, the content of Mn in the coating is less, and the conductivity decreases.

The above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the present invention. within the scope of protection.

Claims (10)

1. a preparation method of Y-doped Co-Mn spinel coating, is characterized in that, comprises the steps: Step 1: Preprocessing A ferritic stainless steel substrate is provided. After grinding, it is first soaked in NaOH solution, taken out, cleaned, then soaked in H ₂ SO ₄ solution, taken out, cleaned, and then subjected to electrolytic corrosion treatment to obtain a pretreated substrate; Step 2: Preparation of Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating The pretreated substrate obtained in step 1 is used as the cathode, and the double cobalt plate is used as the double anode, which is placed in the deposition solution, and direct current is applied to deposit the Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating; wherein , the deposition solution contains 80g/L-160g/L Mn ₃ O ₄ , 5g/L-15g/L Y ₂ O ₃ , 300g/L CoSO ₄ ·7H ₂ O, 50g/L CoCl _2. 6H ₂ O, 15g/L H ₃ BO ₃ , 10g/L sodium gluconate and 0.03g/L sodium lauryl sulfate, pH 3-5; Step 3: Preparation of Y-doped Co-Mn spinel coating The Co-Y ₂ O ₃ -Mn ₃ O ₄ composite precursor coating obtained in step 2 is converted into a Y-doped Co-Mn spinel coating through heat treatment. 2. the preparation method of Y-doped Co-Mn spinel coating according to claim 1, is characterized in that, in step 1, the model of described ferritic stainless steel is in SUS430, E-brite and Crofer22 Any one; the grinding refers to grinding the ferritic stainless steel substrate with 200-mesh, 400-mesh and 800-mesh sandpapers in sequence. 3. the preparation method of Y-doped Co-Mn spinel coating according to claim 1, is characterized in that, in step 1, the time of described soaking is 10min, described NaOH solution and described H ₂ The concentrations of SO ₄ solutions were all 1 mol/L, and deionized water was used for the cleaning. 4. the preparation method of Y-doped Co-Mn spinel coating according to claim 1, is characterized in that, in step 1, described electrolytic corrosion treatment refers to that the substrate after cleaning is placed in electrolytic corrosion solution , at room temperature, corrode for 5 minutes, wherein, the electrolytic corrosion solution contains 50 g/L of CoCl ₂ ·6H ₂ O and 1 mol/L of HCl, and the pH value is 5. 5. the preparation method of Y-doped Co-Mn spinel coating according to claim 1, is characterized in that, in step 2, the spacing of described cathode and described double anode in deposition solution is 35mm, Arranged in an equilateral triangle. 6. The preparation method of Y-doped Co-Mn spinel coating according to claim 1, characterized in that, in step 2, the current density of the direct current is 10mA/cm ² -30mA/cm ² , applying The voltage is 1V-5V. 7. the preparation method of Y-doped Co-Mn spinel coating according to claim 1, is characterized in that, in step 2, the electromagnetic stirring rate that described deposition adopts is 700r/min-900r/min, time For 10min-20min. 8. The preparation method of Y-doped Co-Mn spinel coating according to claim 1, characterized in that, in step 3, the heat treatment conversion temperature is 800°C, and the heating rate is 1°C/min-5 ℃/min, the heat treatment conversion time is 60min. 9. A Y-doped Co-Mn spinel coating prepared by the preparation method of any one of claims 1-8. 10. Application of the Y-doped Co-Mn spinel coating prepared by the preparation method according to any one of claims 1 to 8 in a protective coating as a SOFC connector material.

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