Preparation method of MLCC sintering nickel net coating

Abstract

The application belongs to the technical field of coating preparation, and relates to a preparation method of a MLCC sintering supporting nickel mesh coating, comprising the following steps: base body pretreatment: performing cleaning degreasing, drying and surface roughening treatment on the nickel mesh base body to obtain a clean nickel mesh base body with a rough structure; plasma spraying: selecting spherical yttrium oxide partially stabilized zirconium oxide powder, drying and removing water, and then adopting an atmospheric plasma spraying mode to prepare a coating on the surface of the nickel mesh base body by adjusting process parameters and multi-angle spraying; coating post-treatment: placing the sprayed nickel mesh in a protective atmosphere for high-temperature heat treatment, slowly cooling after heat preservation, completing coating solidification densification, and obtaining a modified MLCC sintering supporting nickel mesh. The zirconium oxide coating has excellent thermal stability and high-temperature chemical stability, can block the contact between a MLCC product and the nickel mesh base body in a sintering process, inhibit high-temperature oxidation, creep and deformation of the nickel mesh, prolong the service life, and meet the high-temperature sintering working condition requirements.

Description

Technical Field

[0001] This invention belongs to the field of coating preparation technology, specifically relating to a method for preparing a sintered nickel mesh coating for MLCCs. Background Technology

[0002] Multilayer ceramic capacitors (MLCCs), as a core category of electronic components, have advantages such as small size, large capacitance, and good high-frequency characteristics, and are widely used in consumer electronics, new energy, and communication equipment. In the MLCC production process, high-temperature sintering is a key process that determines its performance and yield, and the performance of the sintering substrate directly affects the dimensional accuracy, surface quality, and batch stability of the MLCC after sintering.

[0003] Nickel mesh has become the mainstream sintering carrier for MLCCs due to its high temperature resistance, good thermal conductivity, high strength, and moderate cost. However, under actual high-temperature sintering conditions (temperatures can reach over 1000℃), exposed nickel mesh has significant defects: First, it is prone to oxidation and creep in high-temperature environments, leading to wire deformation and breakage, and a significantly shortened service life; second, the rough surface of the nickel mesh makes it easy to stick to the MLCC blank during sintering, causing scratches and ceramic chipping on the product surface, reducing the yield rate; third, nickel elements are prone to diffusion and migration at high temperatures, contaminating the ceramic dielectric layer of the MLCC and affecting the electrical performance of the capacitor; fourth, after repeated high-temperature thermal shocks, the surface of the nickel mesh is prone to local peeling and carbon buildup, further aggravating the adverse effects on the MLCC product.

[0004] To address the aforementioned issues, the industry commonly employs a protective solution involving the preparation of ceramic coatings on the surface of nickel mesh. Commonly used coating materials include alumina and zirconium oxide. Existing preparation processes primarily involve spraying, dipping, and brushing. However, conventional plasma spraying has significant drawbacks: First, the uneven particle size and poor sphericity of the sprayed powder easily lead to low coating density, high porosity, and rapid degradation of protective effectiveness at high temperatures. Second, the limited spraying angle and poor matching of process parameters make it difficult for the coating to uniformly coat the nickel mesh wire, resulting in uneven thickness, missed areas, and cracking. Customer feedback indicates frequent instances of coating breakage and discontinuity. Third, the post-coating processing is inadequate, resulting in weak adhesion between the coating and the nickel mesh substrate, leading to easy detachment and failure after repeated high-temperature sintering cycles. Fourth, existing processes are difficult to adapt to the differentiated coating requirements of nickel meshes with different mesh sizes (e.g., 32 mesh, 60 mesh), exhibiting poor versatility and significant coating thickness fluctuations, making it difficult to stably control within the required process range.

[0005] In summary, existing MLCC sintering nickel mesh coating technologies suffer from drawbacks such as poor coating uniformity, low density, weak adhesion, short service life, and insufficient adaptability, failing to meet the demands of large-scale, high-quality, and long-cycle sintering production of high-end MLCCs. Therefore, there is an urgent need to develop a method for preparing MLCC sintering nickel mesh coatings that features uniform and dense coating, strong adhesion to the substrate, high-temperature resistance and oxidation resistance, and compatibility with various nickel mesh specifications. This will address the shortcomings of existing technologies and improve the service life of nickel meshes and the yield rate of MLCC products. Summary of the Invention

[0006] To address the problems mentioned in the background art, this invention proposes a method for preparing a sintered nickel mesh coating for MLCCs. By using spherical yttrium oxide partially stabilized zirconium oxide powder in conjunction with multi-angle plasma spraying, a continuous, uniform, and leak-free zirconium oxide coating can be formed on the surface of the nickel mesh, completely encapsulating the nickel wire. The thickness is stable and controllable, effectively avoiding defects such as uneven thickness, breakage, and discontinuity.

[0007] The technical solution adopted by this invention to solve its technical problem is: to provide a method for preparing a sintered nickel mesh coating for MLCCs, comprising the following steps:

[0008] S1. Substrate pretreatment: The nickel mesh substrate is cleaned and degreased to remove contaminants from the substrate surface, and then dried; the dried nickel mesh substrate is then subjected to surface roughening treatment to obtain a clean nickel mesh substrate with a rough structure.

[0009] S2. Plasma spraying: Spherical yttrium oxide partially stabilized zirconium oxide powder is selected as the spraying material. The powder is pretreated by drying and dehydration. Atmospheric plasma spraying is used to spray the coating onto the pretreated nickel mesh substrate. During the spraying process, the spraying process parameters are controlled and a multi-angle spraying method is adopted.

[0010] S3. Post-coating treatment: The coated nickel mesh is placed in a protective atmosphere for high-temperature heat treatment, and then slowly cooled after heat preservation to complete the curing and densification treatment of the nickel mesh coating, thus obtaining the modified MLCC sintered nickel mesh.

[0011] Furthermore, in step S1, the cleaning and degreasing treatment adopts an ultrasonic cleaning process. First, ultrasonic cleaning is performed using deionized water or dilute alkaline cleaning solution with added surfactants, and then a second ultrasonic cleaning is performed using an organic solvent. After each cleaning, high-purity deionized water is used for rinsing.

[0012] Further, the surfactant includes fatty alcohol polyoxyethylene ether, alkyl glycoside, or fatty acid methyl ester ethoxylate; the dilute alkaline cleaning solution includes one or more compound aqueous solutions of sodium hydroxide, sodium carbonate, and trisodium phosphate, with a mass concentration of 2% to 5%; the ultrasonic cleaning temperature of the dilute alkaline cleaning solution is 40℃ to 60℃, and the cleaning time is 10 to 30 minutes; the organic solvent includes any one of anhydrous ethanol, acetone, and isopropanol, and the ultrasonic cleaning time of the organic solvent is 5 to 15 minutes.

[0013] Furthermore, in step S1, the drying method is drying in a blower drying oven or drying with clean hot air, the drying temperature is 60℃~80℃, and the drying time is 30~60min.

[0014] Furthermore, in step S1, the surface roughening treatment is carried out by sandblasting with a sandblasting machine. White corundum sand is selected as the sandblasting abrasive. After sandblasting, the surface of the nickel mesh is blown to remove residual abrasive dust.

[0015] Furthermore, the white corundum abrasive has a mesh size of 100-200; the compressed air pressure for sandblasting is 0.1-0.4 MPa; the distance between the sandblasting gun and the nickel mesh plane is 250-350 mm; the sandblasting is performed in four directions at 45° angles with alternating blasting; the moving speed of the nickel mesh is 5-15 mm / min; each side is sandblasted 2-4 times; and the surface roughness Ra value of the nickel mesh after sandblasting is 1.5-3.0 μm.

[0016] Furthermore, in step S2, the particle size distribution range of the spherical yttrium oxide partially stabilized zirconium oxide powder is 20~70μm; the powder drying temperature is 100℃~150℃, and the drying time is 2~4h.

[0017] Further, in step S2, the process parameters for atmospheric plasma spraying are as follows: spraying current 400~600A, main gas argon flow rate 30~50L / min, secondary gas is hydrogen or helium, secondary gas flow rate 5~15L / min, powder feeding rate 30~70g / min, spray gun power 30~50KW, spraying distance 100~200mm, spraying speed 100~300mm / s; the spraying adopts a four-way 45° multi-angle alternating spraying method.

[0018] Furthermore, during the spraying process in step S2, compressed air or inert gas is used to cool the nickel mesh substrate to prevent high-temperature deformation of the substrate; after spraying, the average coating thickness is 0.03~0.10mm.

[0019] Further, in step S3, the protective atmosphere is an inert atmosphere or a reducing atmosphere, the inert atmosphere is high-purity argon or nitrogen, and the reducing atmosphere is hydrogen; the heat treatment temperature is 800℃~1200℃, and the holding time is 1~4h.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] (1) The present invention uses spherical yttrium oxide partially stabilized zirconium oxide powder, combined with multi-angle plasma spraying, to form a continuous, uniform, and unobstructed zirconium oxide coating on the surface of the nickel mesh, completely covering the nickel wire, with stable and controllable thickness, effectively avoiding defects such as uneven thickness, breakage and discontinuity.

[0022] (2) The zirconium oxide coating of the present invention has good thermal stability and high high-temperature chemical stability, which can effectively block the contact between air and nickel mesh substrate, significantly inhibit high-temperature oxidation, creep and deformation of nickel mesh, greatly extend service life and meet the requirements of long-term high-temperature sintering conditions.

[0023] (3) Through the synergistic effect of substrate sandblasting roughening, plasma spraying and high temperature post-treatment in protective atmosphere, the coating is firmly bonded to the nickel mesh substrate, with high density and low porosity. It can withstand multiple high temperature thermal shocks, and will not peel off or crack after long-term use, thus significantly improving reliability.

[0024] (4) The dense zirconium oxide coating of the present invention can effectively block the diffusion of nickel elements and avoid contamination of the MLCC ceramic dielectric layer; at the same time, it reduces problems such as blank adhesion, ceramic chipping, and scratches, and significantly improves the surface quality and yield of MLCC products.

[0025] (5) The process parameters of the present invention are controllable and can be stably adapted to different specifications of nickel mesh such as 32 mesh and 60 mesh. The coating thickness can be precisely controlled within the required range. The process has good stability and repeatability and is suitable for large-scale industrial production. Attached Figure Description

[0026] Figure 1 This is a microscopic cross-sectional view of the modified MLCC sintered nickel mesh prepared in Example 1 of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1:

[0029] A method for preparing a sintered nickel mesh coating for MLCCs includes the following steps:

[0030] S1. Substrate Pretreatment: Take a 60-mesh nickel mesh substrate and degrease it using ultrasonic cleaning. First, use a dilute alkaline solution of 3% sodium hydroxide + sodium carbonate at 50℃ for 20 minutes of ultrasonic cleaning; then use anhydrous ethanol for 10 minutes of ultrasonic cleaning; after each cleaning, rinse with high-purity deionized water. Then place it in a forced-air drying oven at 70℃ for 45 minutes. After drying, perform sandblasting roughening: use 150-mesh white corundum abrasive, compressed air pressure of 0.25MPa, spray gun distance of 300mm from the nickel mesh, sandblasting at 45° in four directions alternately, nickel mesh moving speed of 10mm / min, sandblasting three times on each side, the surface roughness Ra after treatment is 2.2μm, and blow away dust.

[0031] S2. Plasma Spraying: Spherical yttrium oxide partially stabilized zirconia powder with a particle size of 20~70μm is selected; the powder is dried at 120℃ for 3h. Atmospheric plasma spraying parameters: current 500A, main gas argon 40L / min, secondary gas hydrogen 10L / min, powder feed rate 50g / min, spray gun power 40kW, spraying distance 150mm, spraying speed 200mm / s; four-way 45° alternating spraying, the substrate is cooled with compressed air during the spraying process, and the average coating thickness is 0.06mm.

[0032] S3. Post-coating treatment: The coated nickel mesh is placed in a high-purity argon protective atmosphere and kept at 1000℃ for 2.5h. It is then slowly cooled in the furnace to complete the curing and densification, thus obtaining the modified MLCC sintered nickel mesh.

[0033] like Figure 1 The image shown is a micrograph of the cross-section of a single filament of a yttrium oxide partially stabilized zirconium oxide coated nickel mesh prepared in Example 1. Figure 1 As can be seen, the bright white area in the center is the nickel mesh substrate, which is a regular circle. The surface is covered with a uniform, continuous and dense gray ceramic coating. The coating has no obvious peeling, cracking or pore defects and completely covers the surface of the nickel wire. The coating thickness is about 15~20μm.

[0034] Example 2

[0035] A method for preparing a sintered nickel mesh coating for MLCCs includes the following steps:

[0036] S1. Substrate Pretreatment: Take a 32-mesh nickel mesh substrate and degrease it using ultrasonic cleaning. First, use a 2% trisodium phosphate dilute alkaline solution for ultrasonic cleaning at 45℃ for 15 minutes; then use acetone for ultrasonic cleaning for 8 minutes; after each cleaning, rinse with high-purity deionized water. Then place it in a forced-air drying oven at 65℃ for 50 minutes. After drying, perform sandblasting roughening: use 120-mesh white corundum abrasive, compressed air pressure 0.2MPa, spray gun distance 280mm from the nickel mesh, sandblasting at 45° in four directions alternately, nickel mesh moving speed 8mm / min, sandblasting each side twice, the surface roughness Ra after treatment is 1.8μm, and dust is removed by blowing.

[0037] S2. Plasma Spraying: Spherical yttrium oxide partially stabilized zirconia powder with a particle size of 20~70μm is selected; the powder is dried at 110℃ for 4h. Atmospheric plasma spraying parameters: current 450A, main gas argon 35L / min, secondary gas helium 8L / min, powder feed rate 40g / min, spray gun power 35kW, spraying distance 120mm, spraying speed 150mm / s; four-way 45° alternating spraying, the substrate is cooled with inert gas during the spraying process, and the average coating thickness is 0.04mm.

[0038] S3. Post-coating treatment: The coated nickel mesh is placed in a high-purity nitrogen protective atmosphere and kept at 900℃ for 2 hours. It is then slowly cooled in the furnace to complete the curing and densification, thus obtaining the modified MLCC sintered nickel mesh.

[0039] Example 3

[0040] A method for preparing a sintered nickel mesh coating for MLCCs includes the following steps:

[0041] S1. Substrate Pretreatment: Take a 60-mesh nickel mesh substrate and degrease it using ultrasonic cleaning. First, use a 5% sodium carbonate dilute alkaline solution for ultrasonic cleaning at 60℃ for 30 minutes; then use isopropanol for ultrasonic cleaning for 12 minutes; after each cleaning, rinse with high-purity deionized water. Then place it in a forced-air drying oven at 80℃ for 30 minutes. After drying, perform sandblasting roughening: use 200-mesh white corundum abrasive, compressed air pressure 0.35MPa, spray gun distance 320mm from the nickel mesh, sandblasting at 45° in four directions alternately, nickel mesh moving speed 12mm / min, sandblasting 4 times on each side, the surface roughness Ra after treatment is 2.8μm, and blow away dust.

[0042] S2. Plasma Spraying: Spherical yttrium oxide partially stabilized zirconia powder with a particle size of 20~70μm is selected; the powder is dried at 140℃ for 2h. Atmospheric plasma spraying parameters: current 550A, main gas argon 45L / min, secondary gas hydrogen 12L / min, powder feed rate 60g / min, spray gun power 45kW, spraying distance 180mm, spraying speed 250mm / s; four-way 45° alternating spraying, compressed air is used to cool the substrate during the spraying process, and the average coating thickness is 0.08mm.

[0043] S3. Post-coating treatment: The coated nickel mesh is placed in a high-purity argon protective atmosphere and kept at 1100℃ for 3 hours. It is then slowly cooled in the furnace to complete the curing and densification, thus obtaining the modified MLCC sintered nickel mesh.

[0044] Example 4

[0045] A method for preparing a sintered nickel mesh coating for MLCCs includes the following steps:

[0046] S1. Substrate Pretreatment: Take a 32-mesh nickel mesh substrate and degrease it using ultrasonic cleaning. First, use a 3% sodium hydroxide dilute alkaline solution for ultrasonic cleaning at 40℃ for 25 minutes; then use anhydrous ethanol for ultrasonic cleaning for 5 minutes; after each cleaning, rinse with high-purity deionized water. Then place it in a forced-air drying oven at 60℃ for 60 minutes. After drying, perform sandblasting roughening: use 100-mesh white corundum abrasive, compressed air pressure 0.15MPa, spray gun distance 250mm from the nickel mesh, sandblasting at 45° in four directions alternately, nickel mesh moving speed 5mm / min, sandblasting each side 3 times, after treatment the surface roughness Ra=1.5μm, blow away dust.

[0047] S2. Plasma Spraying: Spherical yttrium oxide partially stabilized zirconia powder with a particle size of 20~70μm is selected; the powder is dried at 100℃ for 3.5h. Atmospheric plasma spraying parameters: current 400A, main gas argon 30L / min, secondary gas helium 5L / min, powder feed rate 30g / min, spray gun power 30kW, spraying distance 100mm, spraying speed 100mm / s; four-way 45° alternating spraying, compressed air is used to cool the substrate during the spraying process, and the average coating thickness is 0.03mm.

[0048] S3. Post-coating treatment: The coated nickel mesh is placed in a hydrogen reducing atmosphere and kept at 850℃ for 1.5h. It is then slowly cooled in the furnace to complete the curing and densification, thus obtaining the modified MLCC sintered nickel mesh.

[0049] Example 5

[0050] A method for preparing a sintered nickel mesh coating for MLCCs includes the following steps:

[0051] S1. Substrate Pretreatment: Take a 60-mesh nickel mesh substrate and degrease it using ultrasonic cleaning. First, use deionized water with added fatty alcohol polyoxyethylene ether for ultrasonic cleaning at 55℃ for 18 minutes; then use acetone for ultrasonic cleaning for 15 minutes; rinse with high-purity deionized water after each cleaning. Then place it in a forced-air drying oven at 75℃ for 40 minutes. After drying, perform sandblasting roughening: use 180-mesh white corundum abrasive, compressed air pressure 0.4MPa, spray gun distance 350mm from nickel mesh, sandblasting at 45° in four directions alternately, nickel mesh moving speed 15mm / min, sandblasting 3 times per side, after which the surface roughness Ra=3.0μm, and blow away dust.

[0052] S2. Plasma Spraying: Spherical yttrium oxide partially stabilized zirconia powder with a particle size of 20~70μm is selected; the powder is dried at 130℃ for 2.5h. Atmospheric plasma spraying parameters: current 600A, main gas argon 50L / min, secondary gas hydrogen 15L / min, powder feed rate 70g / min, spray gun power 50kW, spraying distance 200mm, spraying speed 300mm / s; four-way 45° alternating spraying, the substrate is cooled with inert gas during the spraying process, and the average coating thickness is 0.10mm.

[0053] S3. Post-coating treatment: The coated nickel mesh is placed in a high-purity argon protective atmosphere and kept at 1200℃ for 4 hours. It is then slowly cooled in the furnace to complete the curing and densification, thus obtaining the modified MLCC sintered nickel mesh.

[0054] Comparative Example 1: Blank uncoated nickel mesh

[0055] A sintered nickel mesh for MLCCs, without coating modification, is prepared by the following steps:

[0056] Substrate pretreatment: A 60-mesh nickel mesh substrate was taken and degreased using ultrasonic cleaning. First, a dilute alkaline solution of 3% sodium hydroxide and sodium carbonate was used for ultrasonic cleaning at 50°C for 20 minutes; then, anhydrous ethanol was used for ultrasonic cleaning for 10 minutes; after each cleaning, the substrate was rinsed with high-purity deionized water. Subsequently, it was placed in a forced-air drying oven and dried at 70°C for 45 minutes. After drying, sandblasting roughening was performed: 150-mesh white corundum abrasive was used, with compressed air pressure of 0.25 MPa, the spray gun distance from the nickel mesh was 300 mm, and sandblasting was performed alternately at 45° in four directions. The nickel mesh moving speed was 10 mm / min, and each side was sandblasted 3 times. After treatment, the surface roughness Ra = 2.2 μm. Dust was removed by blowing, and a blank sintered nickel mesh was obtained.

[0057] Comparative Example 2: Conventional alumina-coated nickel mesh

[0058] A method for preparing a nickel mesh coating for sintering MLCCs, using a conventional alumina coating, includes the following steps:

[0059] S1. Substrate Pretreatment: Take a 60-mesh nickel mesh substrate and degrease it using ultrasonic cleaning. First, use a dilute alkaline solution of 3% sodium hydroxide + sodium carbonate at 50℃ for 20 minutes of ultrasonic cleaning; then use anhydrous ethanol for 10 minutes of ultrasonic cleaning; after each cleaning, rinse with high-purity deionized water. Then place it in a forced-air drying oven at 70℃ for 45 minutes. After drying, perform sandblasting roughening: use 150-mesh white corundum abrasive, compressed air pressure of 0.25MPa, spray gun distance of 300mm from the nickel mesh, sandblasting at 45° in four directions alternately, nickel mesh moving speed of 10mm / min, sandblasting three times on each side, the surface roughness Ra after treatment is 2.2μm, and blow away dust.

[0060] S2. Plasma Spraying: Spherical alumina powder with a particle size of 20~70μm is selected; the powder is dried at 120℃ for 3h. Atmospheric plasma spraying parameters: current 500A, main gas argon 40L / min, secondary gas hydrogen 10L / min, powder feed rate 50g / min, spray gun power 40kW, spraying distance 150mm, spraying speed 200mm / s; four-way 45° alternating spraying, compressed air is used to cool the substrate during the spraying process, and the average coating thickness is 0.06mm.

[0061] S3. Post-coating treatment: The coated nickel mesh is placed in a high-purity argon protective atmosphere and kept at 1000℃ for 2.5h. It is then slowly cooled in the furnace to complete the curing and densification, thus obtaining an alumina-coated modified MLCC sintered nickel mesh.

[0062] Table 1 shows the performance test results of the modified MLCC sintered nickel mesh prepared in Examples 1-5 and Comparative Examples 1 and 2.

[0063]

[0064] In summary, the MLCC sintering nickel mesh coating preparation method provided by this invention, through the synergistic process of precise substrate pretreatment, multi-angle plasma spraying of spherical yttrium-stabilized zirconia powder, and high-temperature densification post-treatment under a protective atmosphere, successfully prepared a zirconia ceramic coating with uniform thickness, high density, strong adhesion, and high-temperature oxidation resistance. As shown in the test results of Examples 1-5, the coated nickel mesh prepared by this invention exhibits significantly better performance than blank nickel mesh and conventional alumina-coated nickel mesh: the bonding strength between the coating and the substrate can reach 42-53 MPa, and the long-term oxidation weight gain at 1100℃ is as low as 0.05-0.15 mg / cm³. 2 The stability of the MLCC is ≥72 cycles of thermal shock from 1000℃ to room temperature, the nickel diffusion depth is <1.8μm, and the sintering adhesion and ceramic chipping defect rate is controlled within the range of 0.07%~0.23%.

[0065] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a sintered nickel mesh coating for MLCCs, characterized in that, Includes the following steps: S1. Substrate pretreatment: The nickel mesh substrate is cleaned and degreased to remove contaminants from the substrate surface, and then dried; the dried nickel mesh substrate is then subjected to surface roughening treatment to obtain a clean nickel mesh substrate with a rough structure. S2. Plasma spraying: Spherical yttrium oxide partially stabilized zirconium oxide powder is selected as the spraying material. The powder is pretreated by drying and dehydration. Atmospheric plasma spraying is used to spray the coating onto the pretreated nickel mesh substrate. During the spraying process, the spraying process parameters are controlled and a multi-angle spraying method is adopted. S3. Post-coating treatment: The coated nickel mesh is placed in a protective atmosphere for high-temperature heat treatment, and then slowly cooled after heat preservation to complete the curing and densification treatment of the nickel mesh coating, thus obtaining the modified MLCC sintered nickel mesh.

2. The method for preparing a sintered nickel mesh coating for MLCCs according to claim 1, characterized in that, In step S1, the cleaning and degreasing process adopts an ultrasonic cleaning process. First, ultrasonic cleaning is performed using deionized water or dilute alkaline cleaning solution with added surfactants. Then, a second ultrasonic cleaning is performed using an organic solvent. After each cleaning, high-purity deionized water is used for rinsing.

3. The coating preparation method for a sintered nickel mesh for MLCCs according to claim 2, characterized in that, The surfactant includes fatty alcohol polyoxyethylene ether, alkyl glycoside, or fatty acid methyl ester ethoxylate; the dilute alkaline cleaning solution includes one or more compound aqueous solutions of sodium hydroxide, sodium carbonate, and trisodium phosphate, with a mass concentration of 2% to 5%; the ultrasonic cleaning temperature of the dilute alkaline cleaning solution is 40℃ to 60℃, and the cleaning time is 10 to 30 minutes; the organic solvent includes any one of anhydrous ethanol, acetone, and isopropanol, and the ultrasonic cleaning time of the organic solvent is 5 to 15 minutes.

4. The method for preparing a sintered nickel mesh coating for MLCCs according to claim 1, characterized in that, In step S1, the drying method is drying in a blower drying oven or drying with clean hot air, the drying temperature is 60℃~80℃, and the drying time is 30~60min.

5. The method for preparing a sintered nickel mesh coating for MLCCs according to claim 1, characterized in that, In step S1, the surface roughening treatment is carried out by sandblasting machine, and white corundum sand is selected as the sandblasting abrasive. After sandblasting, the surface of the nickel mesh is blown to remove residual abrasive dust.

6. The method for preparing a sintered nickel mesh coating for MLCCs according to claim 5, characterized in that, The white corundum abrasive has a mesh size of 100-200; the compressed air pressure for sandblasting is 0.1-0.4 MPa; the distance between the sandblasting gun and the nickel mesh plane is 250-350 mm; the sandblasting is carried out in four directions at 45° angles with alternating sandblasting; the moving speed of the nickel mesh is 5-15 mm / min; each side is sandblasted 2-4 times; and the surface roughness Ra value of the nickel mesh after sandblasting is 1.5-3.0 μm.

7. The method for preparing a sintered nickel mesh coating for MLCCs according to claim 1, characterized in that, In step S2, the particle size distribution range of the spherical yttrium oxide partially stabilized zirconium oxide powder is 20~70μm; the powder drying temperature is 100℃~150℃, and the drying time is 2~4h.

8. The method for preparing a sintered nickel mesh coating for MLCCs according to claim 1, characterized in that, In step S2, the process parameters for atmospheric plasma spraying are as follows: spraying current 400~600A, main gas argon flow rate 30~50L / min, secondary gas is hydrogen or helium, secondary gas flow rate 5~15L / min, powder feeding rate 30~70g / min, spray gun power 30~50KW, spraying distance 100~200mm, spraying speed 100~300mm / s; the spraying adopts a four-way 45° multi-angle alternating spraying method.

9. The method for preparing a sintered nickel mesh coating for MLCCs according to claim 1, characterized in that, During the spraying process in step S2, compressed air or inert gas is used to cool the nickel mesh substrate to prevent high-temperature deformation of the substrate; After spraying, the average coating thickness is 0.03~0.10mm.

10. The method for preparing a sintered nickel mesh coating for MLCCs according to claim 1, characterized in that, In step S3, the protective atmosphere is an inert atmosphere or a reducing atmosphere. The inert atmosphere is high-purity argon or nitrogen, and the reducing atmosphere is hydrogen. The heat treatment temperature is 800℃~1200℃, and the holding time is 1~4h.

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