Setter plate for high-voltage ceramic capacitor and preparation method thereof

Abstract

The invention relates to a load bearing plate for a high-voltage ceramic capacitor and a preparation method thereof, the load bearing plate for the high-voltage ceramic capacitor comprises a main body layer, and the surface of the main body layer is sequentially coated with a transition layer and an anti-sticking layer; the composition of the main body layer comprises Al2O3 and SiO2, the composition of the transition layer comprises Al2O3, SiO2, BaTiO3 and SrTiO3, and the composition of the anti-sticking layer comprises BaTiO3 and SrTiO3; and the high-voltage ceramic capacitor is composed of BaTiO3. According to the invention, the transition layer and the anti-sticking layer are sequentially coated on the main body layer, and the anti-sticking layer and the high-voltage ceramic capacitor are designed to have the same composition material, so that adhesion between the load bearing plate and the high-voltage ceramic capacitor can be prevented, the uniformity degree of the product is improved, and the breakdown voltage of the ceramic capacitor is improved.

Description

A sintering plate for high-voltage ceramic capacitors and its preparation method Technical Field

[0001] This invention relates to the field of sintering plate preparation technology, specifically to a sintering plate for high-voltage ceramic capacitors and its preparation method. Background Technology

[0002] A high-voltage ceramic capacitor support plate is a support substrate used in high-temperature sintering processes. It is mainly used to support the high-voltage ceramic capacitor element during the sintering process in a high-temperature environment. Its function is to provide mechanical support, thermal stability and electrical insulation performance, and to ensure that the high-voltage ceramic capacitor can be heated uniformly and maintain its structural integrity during the manufacturing process.

[0003] Currently, the main crystalline phase of commonly used high-voltage ceramic capacitors is titanate-based. During sintering, the lamellar ceramic body may adhere to the firing plate or warp, affecting overall uniformity and leading to adverse consequences such as product breakdown. Existing research on improvements to the firing plate mainly includes methods such as improving raw materials, modifying the physical structure, or surface treatment. Improving raw materials involves using compositions more similar to the product and dopants that enhance the stabilizing phase; improving the physical structure makes the firing plate less prone to adhesion to the product; and surface treatment involves adding a glaze layer to the surface of the firing plate.

[0004] CN112553565A discloses a separator for sintering cemented carbide pressed products. The separator is fabricated on a sintering plate used for sintering cemented carbide pressed products to prevent direct contact between the cemented carbide pressed product and the sintering plate, as well as to prevent chemical reactions caused by mutual influence between the two during sintering. The separator is composed of two or more oxides selected from Al2O3, SiO2, TiO2, MgO, Cr2O3, and ZrO2 with a particle size range of 1-150 μm. It is formed on the sintering plate using flame spraying technology under the action of acetylene and oxygen at 0.10-0.40 MPa. This invention adds a cladding layer to the sintering plate to achieve separation between the product and the sintering plate, but it suffers from complex processes and uneven cladding.

[0005] CN201706895U discloses a zirconia electronic functional ceramic sintering plate, which includes a square body with a corrugated upper surface and a support on the bottom surface. This invention solves the defects of deformation and adhesion that occur during the sintering of electronic components by improving the physical structure of the sintering plate, but the surface physical structure of the sintering plate limits its application to a certain extent. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a sintering plate for high-voltage ceramic capacitors and its preparation method, which significantly reduces the probability of adhesion, improves the uniformity of the product, and thus increases the breakdown voltage of the product.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a sintering plate for high-voltage ceramic capacitors, the sintering plate for high-voltage ceramic capacitors comprising a main body layer, wherein a transition layer and an anti-sticking layer are sequentially coated on the surface of the main body layer.

[0009] The main body layer is composed of Al2O3 and SiO2, the transition layer is composed of Al2O3, SiO2, BaTiO3 and SrTiO3, the anti-sticking layer is composed of BaTiO3 and SrTiO3, and the high-voltage ceramic capacitor is composed of BaTiO3.

[0010] The high-voltage ceramic capacitor bearing plate provided by this invention, by sequentially coating a transition layer and an anti-sticking layer on the main body layer, and by designing the anti-sticking layer to have the same composition material as the high-voltage ceramic capacitor, can prevent the bearing plate and the high-voltage ceramic capacitor from sticking together, thereby improving the uniformity of the product and thus increasing the breakdown voltage of the ceramic capacitor; at the same time, the selection of the composition of the transition layer can make the adjacent layer structures have the same coefficient of thermal expansion, further reducing the adhesion phenomenon caused by thermal stress.

[0011] Preferably, based on a total mass percentage of 100wt%, the main body layer contains 60-80wt% Al2O3 and the balance is SiO2.

[0012] The composition of the main layer contains 60-80 wt% Al2O3, for example, it can be 60 wt%, 65 wt%, 70 wt%, 75 wt% or 80 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] Preferably, the thickness ratio of the transition layer to the anti-adhesive layer is 1:(1.5-2), for example, it can be 1:1.5, 1:1.6, 1:1.8, 1:1.9 or 1:2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] The thickness ratio of the transition layer to the anti-adhesive layer is controlled within a reasonable range, which can maximize the advantages of the anti-adhesive layer while avoiding adhesion problems between the main layer and the anti-adhesive layer.

[0015] In a second aspect, the present invention provides a method for preparing a sintered plate for a high-voltage ceramic capacitor as described in the first aspect, the method comprising the following steps:

[0016] (1) A transition slurry is coated on the surface of the main body layer, and then the first sintering is carried out to obtain the intermediate body of the sintering plate;

[0017] (2) The surface of the intermediate body of the sintering plate obtained in step (1) is coated with an anti-sticking slurry, and then a second sintering is performed to obtain the sintering plate for the high voltage ceramic capacitor.

[0018] The method for preparing a sintering plate for high-voltage ceramic capacitors provided by the present invention achieves the sequential coating of a transition layer and an anti-sticking layer on the surface of the main body layer through two steps of coating slurry and sintering, thereby obtaining a sintering plate that does not stick to the ceramic capacitor, significantly improving the breakdown voltage of the ceramic capacitor.

[0019] Preferably, the raw materials of the transition slurry in step (1) include Al2O3, SiO2, BaO, SrO2 and TiO2 in a mass ratio of 70:(7-9):(7-9):(6-8):(6-8), for example, 70:7:7:8:8, 70:8:8:7:7 or 70:9:9:6:6, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the particle size of the raw material of the transition slurry in step (1) is 30-80μm, for example, it can be 30μm, 40μm, 50μm, 60μm or 80μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the solvent for the transition slurry in step (1) includes water.

[0022] Preferably, the transition slurry in step (1) is a transition slurry obtained by wet ball milling of raw materials and solvent for 1-2 hours. For example, it can be 1 hour, 1.2 hours, 1.5 hours, 1.8 hours or 2 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, the temperature of the first sintering in step (1) is 1290-1310℃, for example, it can be 1290℃, 1295℃, 1300℃, 1305℃ or 1310℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the sintering time in step (1) is 1-3 hours, for example, it can be 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] Preferably, the raw materials of the anti-sticking slurry in step (2) include BaO, SrO2 and TiO2 in a mass ratio of 70:(13-17):(13-17), for example, 70:13:17, 70:14:16, 70:15:15, 70:16:14 or 70:17:13, but are not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] Preferably, the particle size of the raw material of the anti-sticking slurry in step (2) is 30-80μm, for example, it can be 30μm, 40μm, 50μm, 60μm or 80μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] Preferably, the solvent of the anti-sticking slurry in step (2) includes water.

[0028] Preferably, the anti-sticking slurry in step (2) is an anti-sticking slurry obtained by wet ball milling of raw materials and solvent for 1-2 hours. For example, it can be 1 hour, 1.2 hours, 1.5 hours, 1.8 hours or 2 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the second sintering temperature in step (2) is 1340-1460℃, for example, it can be 1340℃, 1370℃, 1400℃, 1430℃ or 1460℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] In this invention, the first and second sintering temperatures are the sintering temperatures of the transition layer and the anti-sticking layer, respectively, which are the sintering temperatures of the glaze. Since the main body layer is composed of Al2O3 and SiO2, its burn-off temperature is approximately between 1713 and 2072°C. Therefore, the burn-off temperature of the main body layer is greater than that of the glaze. The burn-off temperature of the glaze is also higher than that of the ceramic capacitor. This ensures that each layer of material can be sintered sequentially during the sintering process without being damaged or experiencing performance degradation due to excessively high or low temperatures. In other words, the high temperature resistance of the main body layer ensures the stability of the entire sintering process. The temperature gradient design of the transition layer, the anti-sticking layer, and the ceramic capacitor ensures the performance and quality of the capacitor element.

[0031] Preferably, the second sintering time in step (2) is 2-4 hours, for example, it can be 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The high-voltage ceramic capacitor bearing plate provided by this invention, by sequentially coating a transition layer and an anti-sticking layer on the main body layer, and by designing the anti-sticking layer to have the same composition material as the high-voltage ceramic capacitor, can prevent the bearing plate and the high-voltage ceramic capacitor from sticking together, thereby improving the uniformity of the product and thus increasing the breakdown voltage of the ceramic capacitor; at the same time, the selection of the composition of the transition layer can make the adjacent layer structures have the same coefficient of thermal expansion, further reducing the adhesion phenomenon caused by thermal stress. Detailed Implementation

[0034] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0035] Example 1

[0036] This embodiment provides a sintering plate for high-voltage ceramic capacitors. The sintering plate includes a main layer, and the surface of the main layer is sequentially coated with a transition layer and an anti-sticking layer with a thickness ratio of 1:1.8. Based on a total mass percentage of 100wt%, the main layer comprises 70wt% Al2O3, with the balance being SiO2; the transition layer comprises Al2O3, SiO2, BaTiO3, and SrTiO3; the anti-sticking layer comprises BaTiO3 and SrTiO3; and the high-voltage ceramic capacitor comprises BaTiO3.

[0037] The method for preparing the sintered plate for the high-voltage ceramic capacitor includes the following steps:

[0038] (1) Weigh Al2O3, SiO2, BaO, SrO2 and TiO2 raw materials in a mass ratio of 70:8:8:7:7, and then wet ball mill them with water for 1.5 h to obtain a transition slurry; the particle size of the raw materials in the transition slurry is 50 μm; the water content of the transition slurry is such that the transition slurry meets the viscosity required for coating.

[0039] A transition slurry is coated on the surface of the main layer, and then a first sintering is carried out at 1300℃ for 2 hours to obtain the intermediate body of the sintering plate;

[0040] (2) Weigh BaO, SrO2 and TiO2 raw materials in a mass ratio of 70:15:15, and then wet ball mill them with water for 1.5 hours to obtain an anti-sticking slurry; the particle size of the raw materials of the anti-sticking slurry is 50 μm; the water content of the anti-sticking slurry is such that the anti-sticking slurry meets the viscosity required for coating.

[0041] The surface of the intermediate body of the sintering plate obtained in step (1) is coated with an anti-sticking slurry, and then a second sintering is carried out at 1400℃ for 3 hours to obtain the sintering plate for high voltage ceramic capacitors.

[0042] The high-voltage ceramic capacitor bearing plate provided in this embodiment can effectively reduce adhesion to the ceramic capacitor, achieving a yield of up to 92%. In addition, it can improve the temperature uniformity and stress distribution during the firing process, improve the microstructure uniformity of the ceramic capacitor, and increase the breakdown voltage by 25%.

[0043] Example 2

[0044] This embodiment provides a sintering plate for high-voltage ceramic capacitors. The sintering plate includes a main layer, and the surface of the main layer is sequentially coated with a transition layer and an anti-sticking layer with a thickness ratio of 1:1.5. Based on a total mass percentage of 100wt%, the main layer comprises 60wt% Al2O3, with the balance being SiO2; the transition layer comprises Al2O3, SiO2, BaTiO3, and SrTiO3; the anti-sticking layer comprises BaTiO3 and SrTiO3; and the high-voltage ceramic capacitor comprises BaTiO3.

[0045] The method for preparing the sintered plate for the high-voltage ceramic capacitor includes the following steps:

[0046] (1) Weigh Al2O3, SiO2, BaO, SrO2 and TiO2 raw materials in a mass ratio of 70:7:7:8:8, and then wet ball mill them with water for 1 hour to obtain a transition slurry; the particle size of the raw materials in the transition slurry is 30 μm; the water content of the transition slurry is such that the transition slurry meets the viscosity required for coating.

[0047] A transition slurry is coated on the surface of the main layer, and then a first sintering is carried out at 1290℃ for 3 hours to obtain the intermediate body of the sintering plate;

[0048] (2) Weigh BaO, SrO2 and TiO2 raw materials in a mass ratio of 70:13:17, and then wet ball mill them with water for 1 hour to obtain an anti-sticking slurry; the particle size of the raw materials of the anti-sticking slurry is 30 μm; the water content of the anti-sticking slurry is such that the anti-sticking slurry meets the viscosity required for coating.

[0049] The surface of the intermediate body of the sintering plate obtained in step (1) is coated with an anti-sticking slurry, and then a second sintering is carried out at 1340°C for 4 hours to obtain the sintering plate for the high voltage ceramic capacitor.

[0050] Using the high-voltage ceramic capacitor bearing plate provided in this embodiment can effectively reduce adhesion to the ceramic capacitor, and the yield rate can reach 88%. In addition, it can improve the temperature uniformity and stress distribution during the firing process, improve the microstructure uniformity of the ceramic capacitor, and increase the breakdown voltage by 20%.

[0051] Example 3

[0052] This embodiment provides a sintering plate for high-voltage ceramic capacitors. The sintering plate includes a main layer, and the surface of the main layer is sequentially coated with a transition layer and an anti-sticking layer with a thickness ratio of 1:2. Based on a total mass percentage of 100wt%, the main layer comprises 80wt% Al2O3, with the balance being SiO2; the transition layer comprises Al2O3, SiO2, BaTiO3, and SrTiO3; the anti-sticking layer comprises BaTiO3 and SrTiO3; and the high-voltage ceramic capacitor comprises BaTiO3.

[0053] The method for preparing the sintered plate for the high-voltage ceramic capacitor includes the following steps:

[0054] (1) Weigh Al2O3, SiO2, BaO, SrO2 and TiO2 raw materials in a mass ratio of 70:9:9:6:6, and then wet ball mill them with water for 2 hours to obtain a transition slurry; the particle size of the raw materials in the transition slurry is 80 μm; the water content of the transition slurry is such that the transition slurry meets the viscosity required for coating.

[0055] A transition slurry is coated on the surface of the main layer, and then the first sintering is carried out at 1310℃ for 1 hour to obtain the intermediate body of the sintering plate;

[0056] (2) Weigh BaO, SrO2 and TiO2 raw materials in a mass ratio of 70:17:13, and then wet ball mill them with water for 2 hours to obtain an anti-sticking slurry; the particle size of the raw materials of the anti-sticking slurry is 80 μm; the water content of the anti-sticking slurry is such that the anti-sticking slurry meets the viscosity required for coating.

[0057] The surface of the intermediate body of the sintering plate obtained in step (1) is coated with an anti-sticking slurry, and then a second sintering is carried out at 1460°C for 2 hours to obtain the sintering plate for high voltage ceramic capacitors.

[0058] Using the high-voltage ceramic capacitor bearing plate provided in this embodiment can effectively reduce adhesion to the ceramic capacitor, and the yield rate can reach 90%. In addition, it can also improve the temperature uniformity and stress distribution during the firing process, improve the microstructure uniformity of the ceramic capacitor, and increase the breakdown voltage by 21%.

[0059] Example 4

[0060] This embodiment provides a sintering plate for high-voltage ceramic capacitors. The difference from Embodiment 1 is that, except for adjusting the thickness ratio of the transition layer to the anti-sticking layer to 1:1, everything else is the same as in Embodiment 1.

[0061] In this embodiment, due to the insufficient thickness of the anti-sticking layer, it may not effectively isolate the firing plate and the ceramic capacitor, slightly increasing the probability of adhesion. This may also lead to uneven local heat conduction, affecting the firing quality of the ceramic capacitor and reducing product performance consistency. Using the firing plate for high-voltage ceramic capacitors provided in this embodiment, the yield rate is 84%, and the breakdown voltage is increased by 15%.

[0062] Example 5

[0063] This embodiment provides a sintering plate for high-voltage ceramic capacitors. The difference from Embodiment 1 is that, except for adjusting the thickness ratio of the transition layer to the anti-sticking layer to 1:3, everything else is the same as in Embodiment 1.

[0064] In this embodiment, the excessive thickness of the anti-stick layer reduces heat conduction efficiency, leading to uneven temperature distribution during firing and affecting the performance of the ceramic capacitor. Using the high-voltage ceramic capacitor bearing plate provided in this embodiment, the yield rate is 82%, and the breakdown voltage is increased by 13%.

[0065] Example 6

[0066] This embodiment provides a sintering plate for high-voltage ceramic capacitors. The preparation method of the sintering plate for high-voltage ceramic capacitors is different from that of Embodiment 1. Except for adjusting the mass ratio of BaO, SrO2 and TiO2 raw materials in step (2) to 70:10:20, the rest is the same as that of Embodiment 1.

[0067] In this embodiment, the composition of the anti-stick layer exceeds the specified range, which reduces the anti-sticking effect. Using the high-voltage ceramic capacitor substrate provided in this embodiment, the yield rate is 87%, and the breakdown voltage is increased by 16%.

[0068] Example 7

[0069] This embodiment provides a sintering plate for high-voltage ceramic capacitors. The preparation method of the sintering plate for high-voltage ceramic capacitors differs from that of Embodiment 1 in that, except for adjusting the mass ratio of BaO, SrO2 and TiO2 raw materials in step (2) to 60:20:20, the rest is the same as that of Embodiment 1.

[0070] In this embodiment, the composition of the anti-stick layer exceeds the specified range, which reduces the anti-sticking effect. Using the high-voltage ceramic capacitor substrate provided in this embodiment, the yield rate is 86%, and the breakdown voltage is increased by 15%.

[0071] Example 8

[0072] This embodiment provides a sintering plate for high-voltage ceramic capacitors. The difference between the preparation method of the sintering plate for high-voltage ceramic capacitors and that of Embodiment 1 is that, except for adjusting the second sintering temperature in step (2) to 1300℃, the rest is the same as that of Embodiment 1.

[0073] In this embodiment, the second sintering temperature is too low, which reduces the density and anti-sticking effect of the anti-sticking layer. Using the high-voltage ceramic capacitor bearing plate provided in this embodiment, the yield rate is 80%, and the breakdown voltage is increased by 5%.

[0074] Example 9

[0075] This embodiment provides a sintering plate for high-voltage ceramic capacitors. The difference between the preparation method of the sintering plate for high-voltage ceramic capacitors and that of Embodiment 1 is that, except for adjusting the second sintering temperature in step (2) to 1500℃, the rest is the same as that of Embodiment 1.

[0076] In this embodiment, the excessively high second sintering temperature increases thermal stress and energy consumption. Using the high-voltage ceramic capacitor bearing plate provided in this embodiment, the yield rate is 84%, and the breakdown voltage is increased by 10%.

[0077] Comparative Example 1

[0078] This comparative example provides a firing plate for high-voltage ceramic capacitors. The difference from Example 1 is that the surface of the main body layer is not coated with a transition layer and an anti-stick layer, while the rest is the same as Example 1.

[0079] In this comparative example, the surface of the main body layer was not coated with a transition layer and an anti-stick layer, which caused the main body layer to stick to the ceramic capacitor, resulting in a significant drop in yield to 72%. At the same time, it reduced the uniformity of the product and significantly reduced the breakdown voltage.

[0080] In summary, the high-voltage ceramic capacitor bearing plate provided by this invention, by sequentially coating a transition layer and an anti-sticking layer on the main body layer, and by designing the anti-sticking layer to have the same compositional material as the high-voltage ceramic capacitor, can prevent the bearing plate and the high-voltage ceramic capacitor from sticking together, thereby improving the uniformity of the product and thus increasing the breakdown voltage of the ceramic capacitor. At the same time, the selection of the composition of the transition layer can ensure that the adjacent layer structures have materials with the same coefficient of thermal expansion, further reducing the adhesion phenomenon caused by thermal stress.

[0081] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A firing plate for high-voltage ceramic capacitors, characterized in that, The high-voltage ceramic capacitor bearing plate includes a main body layer, and the surface of the main body layer is sequentially coated with a transition layer and an anti-sticking layer; the main body layer is composed of Al2O3 and SiO2, the transition layer is composed of Al2O3, SiO2, BaTiO3 and SrTiO3, and the anti-sticking layer is composed of BaTiO3 and SrTiO3; the high-voltage ceramic capacitor is composed of BaTiO3.

2. The sintering plate for high-voltage ceramic capacitors according to claim 1, characterized in that, Based on a total mass percentage of 100wt%, the main layer contains 60-80wt% Al2O3 and the balance is SiO2.

3. The sintering plate for high-voltage ceramic capacitors according to claim 1 or 2, characterized in that, The thickness ratio of the transition layer to the anti-stick layer is 1:(1.5-2).

4. A method for preparing a sintered plate for a high-voltage ceramic capacitor as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) coating the surface of the main body layer with a transition slurry and then performing a first sintering to obtain a sintering plate intermediate; (2) coating the surface of the sintering plate intermediate obtained in step (1) with an anti-sticking slurry and then performing a second sintering to obtain the sintering plate for the high voltage ceramic capacitor.

5. The preparation method according to claim 4, characterized in that, The raw materials of the transition slurry in step (1) include Al2O3, SiO2, BaO, SrO2 and TiO2 in a mass ratio of 70:(7-9):(7-9):(6-8):(6-8); preferably, the particle size of the raw materials of the transition slurry in step (1) is 30-80μm.

6. The preparation method according to claim 5, characterized in that, The solvent of the transition slurry in step (1) includes water; preferably, the transition slurry in step (1) is the transition slurry obtained by wet ball milling of raw materials and solvent for 1-2 hours.

7. The preparation method according to any one of claims 4-6, characterized in that, In step (1), the temperature of the first sintering is 1290-1310℃; preferably, the time of the first sintering in step (1) is 1-3h.

8. The preparation method according to any one of claims 4-7, characterized in that, The raw materials of the anti-sticking slurry in step (2) include BaO, SrO2 and TiO2 in a mass ratio of 70:(13-17):(13-17); preferably, the particle size of the raw materials of the anti-sticking slurry in step (2) is 30-80μm.

9. The preparation method according to claim 8, characterized in that, The solvent of the anti-sticking slurry in step (2) includes water; preferably, the anti-sticking slurry in step (2) is an anti-sticking slurry obtained by wet ball milling of raw materials and solvent for 1-2 hours.

10. The preparation method according to any one of claims 4-9, characterized in that, In step (2), the second sintering temperature is 1340-1460℃; preferably, the second sintering time in step (2) is 2-4h.