A submicron ceramic media powder casting slurry, its preparation method and application

Abstract

This invention belongs to the field of inorganic materials technology, specifically relating to a submicron ceramic dielectric powder casting slurry, its preparation method, and its application. To match different types and particle sizes of ceramic powders and to prepare thin dielectric films of varying thicknesses, this invention provides a submicron ceramic dielectric powder casting slurry, comprising: submicron-sized ceramic powder, dispersant, binder, plasticizer, and organic solvent. The casting slurry composition designed in this invention can match different types and particle sizes of submicron-sized ceramic powders, and can prepare casting slurries of different viscosities according to requirements.

Description

Technical Field

[0001] This invention belongs to the field of inorganic materials technology, specifically relating to a submicron ceramic media powder casting slurry, its preparation method, and its application. Background Technology

[0002] Ceramic dielectric powders are fundamental materials for the fabrication of various ceramic electronic components and are widely used in the fabrication of multilayer components. With the trend towards miniaturization of electronic components, the miniaturization of chip multilayer components places higher demands on ceramic dielectric powders and ceramic films. A key approach to achieving miniaturization of chip multilayer components is the use of thin-layer dielectric ceramic films, and a crucial method for preparing these films is the use of ceramic powders with particle sizes in the nanometer or submicrometer range.

[0003] Casting is an important forming method for thin-film dielectric ceramic materials. Since its inception, casting has been used to produce single-layer or multi-layer thin-film ceramic materials. Currently, casting has become a pillar technology for the production of multilayer capacitors and multilayer ceramic substrates, and is also an essential technology for the production of electronic components. In addition, casting processes can also be used in industries such as papermaking, plastics, and coatings.

[0004] The casting slurry determines the quality of the cast ceramic film, including its strength, toughness, smoothness, and density. Therefore, the composition and ratio of the casting slurry determine the success of the casting process. Casting slurries used in the production of electronic components generally consist of ceramic powder, organic solvents, binders, and plasticizers. The organic solvents typically used are benzene or ketones, which have some toxicity, worsen production conditions, and increase production costs. Secondly, if the composition and ratio of the casting slurry do not match the ceramic powder, it can lead to product cracking and deformation, affecting product quality. Furthermore, there is a compatibility issue between the casting slurry and the preparation process, requiring adjustments based on the ceramic powder particle size and the thickness of the cast film. Adjusting the composition of the casting slurry and the preparation process to match different types and particle sizes of ceramic powder and to prepare thin dielectric films of varying thicknesses is crucial to determining the quality of the cast film. Summary of the Invention

[0005] Therefore, the present invention provides a submicron ceramic medium powder casting slurry and its preparation method, which can be matched with different types and particle sizes of submicron ceramic powders to prepare casting films of different thicknesses and stable quality according to requirements.

[0006] On one hand, the present invention provides a submicron ceramic media powder casting slurry, comprising: submicron-sized ceramic powder, dispersant, binder, plasticizer, and organic solvent;

[0007] Preferably, the submicron-sized ceramic powder comprises at least one of the following: barium titanate powder, lead zirconate titanate powder, barium calcium titanate powder, bismuth ferrite powder, sodium niobate powder, barium titanate powder doped with trace elements, lead zirconate titanate powder doped with trace elements, barium calcium titanate powder doped with trace elements, bismuth ferrite powder doped with trace elements, and sodium niobate powder doped with trace elements.

[0008] More preferably, the trace element includes at least one of Mn, Mg, Ca, Zr, V, Si, Y, and La; the doping amount of the trace element does not exceed 3 at%.

[0009] Preferably, the particle size of the submicron-sized ceramic powder is: D as measured by a laser particle size analyzer. 50 The average particle size, measured by scanning electron microscopy, is between 0.1 and 0.6 μm, ranging from 0.2 to 0.8 μm; the moisture content of the submicron-sized ceramic powder is below 0.5 wt%.

[0010] Preferably, the organic solvent is composed of ethyl acetate and ethanol; wherein the mass ratio of ethyl acetate to ethanol is 2 to 3.

[0011] The mass ratio of the organic solvent to the submicron-sized ceramic powder is 60% to 120%.

[0012] Preferably, the dispersant is an ammonium polycarboxylate salt; more preferably, the dispersant is selected from AKM-0531 (Nippon Oil Company) or SC-0505K (Nippon Oil Company); the mass ratio of the dispersant to the submicron-sized ceramic powder is 1% to 1.5%. This invention matches the particle size of the ceramic powder to achieve uniform dispersion and prevent agglomeration.

[0013] Preferably, the adhesive is polyvinyl butyral with a molecular weight between 40,000 and 120,000, and preferably at least one of BM-2, B-98 or B76;

[0014] The mass ratio of the binder to the submicron-sized ceramic powder is 5% to 12%.

[0015] Preferably, the plasticizer is dioctyl phthalate (DOP), which is chemically pure; the mass ratio of the plasticizer to the submicron-sized ceramic powder is 2% to 4.5%.

[0016] Preferably, the mass ratio of the binder to the plasticizer is 1.6 to 2.6.

[0017] Preferably, when the average particle size of the submicron-sized ceramic powder is 0.1–0.3 μm as determined by scanning electron microscopy, the binder accounts for 5%–8% of the mass of the ceramic powder.

[0018] When scanning electron microscopy tests show that the average particle size of the submicron-sized ceramic powder is 0.3–0.6 μm and does not include 0.3 μm, the binder is PVB, which accounts for 8%–12% of the ceramic powder mass and does not include 8 wt%.

[0019] On the other hand, the present invention provides a method for casting submicron ceramic media powder slurry, comprising:

[0020] (1) Submicron ceramic media powder, dispersant and part of organic solvent are mixed by ball milling or sand milling to obtain a slurry;

[0021] (2) Mix the adhesive, plasticizer and another portion of organic solvent to obtain the glue;

[0022] (3) The obtained glue is added to the well dispersed slurry and ball milled to obtain the submicron ceramic media powder casting slurry.

[0023] The slurry preparation process of this invention includes two pretreatment steps followed by mixing. This method improves powder dispersion and ensures uniform coating of ceramic powder by PVB. The third step of slurry preparation uses ball milling. If the adhesive is not prepared beforehand and powdered PVB is directly added for milling, clumping and incomplete dissolution may occur in the final slurry, leading to an imbalance in the composition of additives. This is due to the limitations of ball milling itself. To ensure batch stability, the adhesive is prepared first, followed by mixing.

[0024] Preferably, the mass ratio of one portion of the organic solvent to the other portion of the organic solvent is (30-70%):(70-30%), more preferably 50%:50%;

[0025] The parameters for the ball milling process include: the grinding balls are yttrium-stabilized zirconia balls; the rotation speed is 120–150 rpm; and the time is 2–4 hours.

[0026] The parameters for the sand milling process include: the grinding balls are yttrium-stabilized zirconia balls; the rotation speed is 1000–2000 rpm; and the time is 2–4 hours.

[0027] A high-speed disperser is used to mix the adhesive during preparation; the high-speed disperser is a disc-shaped paddle; the speed of the high-speed disperser is 600-1000 rpm, and the time is 1-2 hours.

[0028] In another aspect, the present invention provides a cast film strip prepared from submicron ceramic dielectric powder casting slurry; preferably, the casting forming parameters include: the height of the scraper is 40-120 μm (relative height), and the scraper speed is 0.5-2.0 cm / s; preferably, the film thickness of the cast film strip is 3-25 μm.

[0029] The beneficial effects of this invention are:

[0030] Compared with existing technologies, the casting slurry composition designed in this invention can be matched with different types and particle sizes of submicron-sized ceramic powders, and casting slurries of different viscosities can be prepared according to requirements. Furthermore, the preparation method of this invention allows for the full dispersion of ceramic powder and organic additives in an organic solution, forming a uniform and stable casting slurry, enabling the preparation of casting films of varying thicknesses. In addition, the organic solvent system of this invention uses ethanol and ethyl acetate, which, compared to benzene and ketone systems, reduces implementation conditions and production difficulty, causes less harm to the production environment, is more user-friendly, and lowers costs. The slurry composition and preparation process of this invention can produce ceramic films with good quality and uniformity, meeting requirements for ceramic film stability and easy peeling, and can be used to prepare various multilayer chip components, such as multilayer ceramic capacitors, actuators, and sensors. Attached Figure Description

[0031] Figure 1 This is a photograph of the scratch-free and black spot-free membrane strip prepared in Example 1;

[0032] Figure 2 This is a photograph of the scratch-free and black spot-free membrane strip prepared in Example 6;

[0033] Figure 3 This is a graph showing the incomplete dissolution of PVB in Comparative Example 4;

[0034] Figure 4 Image of the scratched membrane strip prepared for Comparative Example 2 Detailed Implementation

[0035] The present invention will be further illustrated by the following embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the present invention.

[0036] This replaces commonly used toxic solvents such as toluene or acetone in existing casting slurries, optimizes the production environment, and allows casting work to be carried out in a more comfortable environment.

[0037] To achieve the above objectives, this invention proposes a ceramic media powder casting slurry composition. The proportions are calculated based on the mass of submicron-sized ceramic powder, which is set to 1. All other components are weighed according to their mass ratio to the ceramic powder. The specific proportions of the remaining components are as follows:

[0038] The organic solvent has a mass ratio of 60% to 120%; the dispersant has a mass ratio of 1% to 1.5%; the binder has a mass ratio of 5% to 12%; and the plasticizer has a mass ratio of 2% to 4.5%.

[0039] Specifically, the submicron-sized ceramic powders include, but are not limited to, barium titanate powder, lead zirconate titanate powder, calcium zirconate titanate powder, sodium niobate powder, bismuth ferrite powder, and formulated powders or ceramic powders doped with trace elements.

[0040] Specifically, the D50 of the submicron-sized ceramic powder measured by the laser particle size analyzer is 0.2–0.8 μm, the average particle size measured by scanning electron microscopy is 0.1–0.6 μm, and the moisture content is below 0.5%.

[0041] Specifically, the organic solvent is composed of ethyl acetate and ethanol, with the mass ratio of the former to the latter being 2 to 3.

[0042] Specifically, the dispersant is AKM-0531 or SC-0505K from Nippon Oil Company.

[0043] Specifically, the adhesive is at least one of BM-2, B-98 or B76, with a molecular weight between 40,000 and 120,000.

[0044] Specifically, the plasticizer is DOP, which is chemically pure;

[0045] Specifically, the adhesive PVB and plasticizer DOP have a certain proportional relationship, with the mass ratio of adhesive to plasticizer being 1.6 to 2.6;

[0046] Specifically, the content of PVB and DOP needs to be adjusted to prepare the slurry depending on the particle size of the submicron-sized ceramic powder used. When the average particle size of the ceramic powder measured by scanning electron microscopy is 0.1–0.3 μm, PVB accounts for 5%–8% of the mass of the ceramic powder, and the mass of DOP is adjusted accordingly based on the ratio with PVB. When the average particle size of the ceramic powder measured by scanning electron microscopy is 0.3–0.6 μm, PVB accounts for 8%–12% of the mass of the ceramic powder, and the mass of DOP is adjusted accordingly based on the ratio with PVB.

[0047] Specifically, depending on the required thickness of the cast film, the viscosity of the slurry needs to be adjusted to match the casting process of the casting machine, and the film thickness is between 3 and 25 μm.

[0048] The following is an exemplary description of the preparation method of the submicron ceramic media powder casting slurry provided by the present invention.

[0049] Powder dispersion: Weigh the ceramic powder, dispersant and organic solvent according to the slurry ratio, and process them in a ball mill or sand mill before use.

[0050] Adhesive preparation: Weigh PVB, DOP and organic solvent according to the slurry ratio, and dissolve them completely using a high-speed disperser. Set aside for later use.

[0051] Slurry dispersion: After the powder dispersion is completed, the prepared glue is added to the dispersed powder in proportion, and then further mixed and dispersed in a ball mill to obtain a uniform and stable slurry required for casting.

[0052] Specifically, the organic solvent in the slurry formulation is divided into two parts in a 1:1 ratio, which are used separately in powder dispersion and glue preparation.

[0053] Specifically, the dispersion method used for powder dispersion is related to the powder particle size (SEM average particle size). When the powder particle size is less than 0.3 μm, a sand mill is used for dispersion, and when the powder particle size is greater than 0.3 μm, a ball mill is used for dispersion.

[0054] Specifically, yttrium-stabilized zirconia balls are used in ball milling and sand milling. The diameter of the zirconia balls used in ball milling is one of 5mm, 3mm and 2mm, and the diameter of the zirconia balls used in sand milling is one of 1mm, 0.6mm, 0.3mm and 0.1mm. The diameter of the zirconia balls is selected according to the particle size of the ceramic powder.

[0055] Specifically, the powder dispersion time is 2-4 hours, the sand mill used is a vertical stirred mill with a multi-layer disc structure, and the grinding speed is 1000-2000 rpm; when using a ball mill, the speed is 120-150 rpm.

[0056] Specifically, when preparing the adhesive, a disc-type paddle disperser is used, with a stirring speed of 600-1000 rpm and a stirring time of 1-2 hours, until the PVB is completely dissolved and a transparent solution is formed.

[0057] Specifically, the slurry is dispersed by ball milling at a speed of 120-150 rpm for 12-16 hours.

[0058] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0059] Example 1

[0060] A submicron ceramic dielectric powder casting slurry composition and its preparation method include the following steps:

[0061] (1) Powder dispersion: 500g of 0.3μm barium titanate formulation powder was added to a vertical stirred mill container. 1mm yttrium-stabilized zirconia balls were used as the grinding medium. AKM-0531 (1% by mass of barium titanate formulation powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (10.5% and 23.5% by mass of barium titanate formulation powder, respectively) were added as organic solvents. After weighing, dispersion began. The stirred mill speed was 2000 rpm, and the grinding time was 2 hours.

[0062] (2) Adhesive preparation: In a beaker of a certain capacity, weigh 6.0% by mass of BM-2 type PVB barium titanate powder as a binder, weigh 2.4% by mass of DOP barium titanate powder as a plasticizer, and then add 10.5% and 23.5% by mass of anhydrous ethanol and ethyl acetate as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 1.5 hours.

[0063] (3) Slurry dispersion: Pour the dispersed barium titanate formulation powder slurry into a ball mill jar. Then, add the pre-prepared glue and start ball milling dispersion. Use 5mm yttrium-stabilized zirconia balls as the grinding medium, ball mill speed 120 rpm, grinding time 16h;

[0064] (4) The barium titanate formulation powder slurry after ball milling was filtered through a 400-mesh nylon filter cloth, the viscosity was tested, and the foam was removed by vacuum for 1 hour. Then the viscosity was tested again. After that, casting began. The height of the scraper was controlled to obtain a 6μm cast film. The film surface was smooth, without scratches or pinholes, and the thickness was uniform.

[0065] Example 2

[0066] A submicron ceramic dielectric powder casting slurry composition and its preparation method include the following steps:

[0067] (1) Powder dispersion: 500g of 0.2μm barium titanate formulation powder was added to a vertical stirred mill container. 1mm yttrium-stabilized zirconia balls were used as the grinding medium. AKM-0531 (1% by mass of barium titanate formulation powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (10.5% and 23.5% by mass of barium titanate formulation powder, respectively) were added as organic solvents. After weighing, dispersion began at a stirred mill speed of 1800 rpm for 2 hours.

[0068] (2) Adhesive preparation: In a beaker of a certain capacity, weigh out 6.0% by mass of B98 type PVB barium titanate powder as the binder, weigh out 2.4% by mass of DOP barium titanate powder as the plasticizer, and then add 15% by mass and 35% by mass of anhydrous ethanol and ethyl acetate as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 2 hours.

[0069] (3) Slurry dispersion: Pour the dispersed barium titanate formulation powder slurry into a ball mill jar. Then, add the pre-prepared glue and start ball milling dispersion. Use 5mm yttrium-stabilized zirconia balls as the grinding medium, ball mill speed 120 rpm, grinding time 16h;

[0070] (4) The barium titanate formulation powder slurry after ball milling was filtered through a 400-mesh nylon filter cloth, and the viscosity was tested. It was then vacuum defoamed for 1.5 hours and the viscosity was tested again. After that, casting began. The height of the scraper was controlled to obtain a 4μm cast film. The film surface was smooth, without scratches or pinholes, and the thickness was uniform.

[0071] Example 3

[0072] A submicron ceramic dielectric powder casting slurry composition and its preparation method include the following steps:

[0073] (1) Powder dispersion: 400g of 0.1μm barium titanate formulation powder was added to a vertical stirred mill container. 1mm yttrium-stabilized zirconia balls were used as the grinding medium. AKM-0531 (1.2% by mass of barium titanate formulation powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (15% and 35% by mass of barium titanate formulation powder, respectively) were added as organic solvents. After weighing, dispersion began at a stirred mill speed of 1600 rpm for 2 hours.

[0074] (2) Adhesive preparation: In a beaker of a certain capacity, weigh 6.0% by mass of BM-2 type PVB barium titanate powder as a binder, weigh 2.4% by mass of DOP barium titanate powder as a plasticizer, and then add 15% and 35% by mass of anhydrous ethanol and ethyl acetate as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 1.5 hours.

[0075] (3) Slurry dispersion: Pour the dispersed barium titanate formulation powder slurry into a ball mill jar. Then, add the pre-prepared glue and start ball milling dispersion. Use 5mm yttrium-stabilized zirconia balls as the grinding medium, ball mill speed 120 rpm, grinding time 16h;

[0076] (4) After ball milling, the barium titanate formulation powder slurry was filtered through a 400-mesh nylon filter cloth, and the viscosity was tested. After vacuum defoaming for 2 hours, the viscosity was tested again. Then, casting began. The height of the scraper was controlled to obtain a 6μm cast film. The film surface was smooth, without scratches or pinholes, and the thickness was uniform.

[0077] Example 4

[0078] A submicron ceramic dielectric powder casting slurry composition and its preparation method include the following steps:

[0079] (1) Powder dispersion: 400g of 0.1μm barium titanate formulation powder was added to a vertical stirred mill container. 1mm yttrium-stabilized zirconia balls were used as the grinding medium. AKM-0531 (1.2% by mass of barium titanate formulation powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (15% and 35% by mass of barium titanate formulation powder, respectively) were added as organic solvents. After weighing, dispersion began at a stirred mill speed of 1600 rpm for 2 hours.

[0080] (2) Adhesive preparation: In a beaker of a certain capacity, weigh 8.0% by mass of BM-2 type PVB barium titanate powder as the binder, weigh 3.2% by mass of DOP barium titanate powder as the plasticizer, and then add 15% and 35% by mass of anhydrous ethanol and ethyl acetate as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 2 hours.

[0081] (3) Slurry dispersion: Pour the dispersed barium titanate formulation powder slurry into a ball mill jar. Then, add the pre-prepared glue and start ball milling dispersion. Use 5mm yttrium-stabilized zirconia balls as the grinding medium, ball mill speed 120 rpm, grinding time 16h;

[0082] (4) After ball milling, the barium titanate formulation powder slurry was filtered through a 400-mesh nylon filter cloth, and the viscosity was tested. After vacuum defoaming for 2 hours, the viscosity was tested again. Then, casting began. The height of the scraper was controlled to obtain a 6μm cast film. The film surface was smooth, without scratches or pinholes, and the thickness was uniform.

[0083] Example 5

[0084] (1) Powder dispersion: 500g of 0.1μm calcium zirconate titanate ceramic powder was added to a vertical stirred mill container. 2mm yttrium-stabilized zirconia balls were used as the grinding medium. AKM-0531 (1.2% by mass of calcium zirconate titanate ceramic powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (15% and 35% by mass of calcium zirconate titanate ceramic powder, respectively) were added as organic solvents. After weighing, dispersion began at a stirred mill speed of 2000 rpm for 2 hours.

[0085] (2) Adhesive preparation: In a beaker of a certain capacity, weigh out 8.0% by weight of B98 type PVB (calcium zirconate titanate ceramic powder) as a binder, weigh out 3.2% by weight of DOP (calcium zirconate titanate ceramic powder) as a plasticizer, and then add 15% and 35% by weight of anhydrous ethanol and ethyl acetate (calcium zirconate titanate ceramic powder) as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 2 hours.

[0086] (3) Slurry dispersion: Pour the dispersed calcium zirconate titanate ceramic powder slurry into a ball mill jar. Then, add the pre-prepared glue and start ball milling dispersion. Use 5mm yttrium-stabilized zirconia balls as the grinding medium, the ball mill speed is 150 rpm, and the grinding time is 16h.

[0087] (4) After ball milling, the calcium zirconate titanate ceramic powder slurry was filtered through a 400-mesh nylon filter cloth, and the viscosity was tested. After vacuum degassing for 2 hours, the viscosity was tested again. Then, casting began. The height of the scraper was controlled to obtain a 12μm cast film. The film surface was smooth, without scratches or pinholes, and the thickness was uniform.

[0088] Example 6

[0089] (1) Powder dispersion: 800g of 0.6μm lead zirconate titanate ceramic powder was added to a ball mill jar. 5mm yttrium-stabilized zirconia balls were used as the grinding medium. SC-0505K (1.0% by mass of lead zirconate titanate ceramic powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (12.5% ​​and 30% by mass of lead zirconate titanate ceramic powder, respectively) were added as organic solvents. After weighing, dispersion began at a ball mill speed of 150 rpm for 4 hours.

[0090] (2) Adhesive preparation: In a beaker of a certain capacity, weigh out 8.5% by weight of B76 type PVB (lead zirconate titanate powder) as a binder, weigh out 3.5% by weight of DOP (lead zirconate titanate powder) as a plasticizer, and then add 12.5% ​​and 30% by weight of anhydrous ethanol and ethyl acetate as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 2 hours.

[0091] (3) Slurry dispersion: Add the pre-prepared glue to the ball mill jar of the dispersed lead zirconate titanate ceramic powder slurry, and start ball milling dispersion. The ball mill speed is 150 rpm and the grinding time is 12 hours.

[0092] (4) After ball milling, the lead zirconate titanate ceramic powder slurry was filtered through a 200-mesh nylon filter cloth, and the viscosity was tested. After vacuum degassing for 2 hours, the viscosity was tested again. Then, casting began. The height of the scraper was controlled to obtain a 15μm cast film. The film surface was smooth, without scratches or pinholes, and the thickness was uniform.

[0093] Example 7

[0094] (1) Powder dispersion: 700g of 0.5μm sodium niobate ceramic powder was added to a ball mill jar. 5mm yttrium-stabilized zirconia balls were used as the grinding medium. SC-0505K (1.0% by mass of sodium niobate ceramic powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (12.5% ​​and 30% by mass of sodium niobate ceramic powder, respectively) were added as organic solvents. After weighing, dispersion began at a ball mill speed of 150 rpm for 4 hours.

[0095] (2) Adhesive preparation: In a beaker of a certain capacity, weigh 8.5% by weight of BM-2 type PVB sodium niobate powder as a binder, weigh 3.5% by weight of DOP sodium niobate powder as a plasticizer, and then add 12.5% ​​and 30% by weight of anhydrous ethanol and ethyl acetate as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 2 hours.

[0096] (3) Slurry dispersion: Add the pre-prepared glue to the ball mill jar of the dispersed sodium niobate porcelain powder slurry, and start ball milling dispersion. The ball mill speed is 150 rpm and the grinding time is 12 hours.

[0097] (4) After ball milling, the sodium niobate ceramic powder slurry was filtered through a 200-mesh nylon filter cloth, and the viscosity was tested. After vacuum defoaming for 2 hours, the viscosity was tested again. Then, casting began. The height of the scraper was controlled to obtain a 15μm cast film. The film surface was smooth, without scratches or pinholes, and the thickness was uniform.

[0098] Example 8

[0099] (1) Powder dispersion: 800g of 0.6μm lead zirconate titanate ceramic powder was added to a ball mill jar. 5mm yttrium-stabilized zirconia balls were used as the grinding medium. SC-0505K (1.0% by mass of lead zirconate titanate ceramic powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (12.5% ​​and 30% by mass of lead zirconate titanate ceramic powder, respectively) were added as organic solvents. After weighing, dispersion began at a ball mill speed of 150 rpm for 4 hours.

[0100] (2) Adhesive preparation: In a beaker of a certain capacity, weigh 10% by weight of B76 type PVB (lead zirconate titanate powder) as a binder, weigh 4.2% by weight of DOP (lead zirconate titanate powder) as a plasticizer, and then add 12.5% ​​and 30% by weight of anhydrous ethanol and ethyl acetate (lead zirconate titanate powder) as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 2 hours.

[0101] (3) Slurry dispersion: Add the pre-prepared glue to the ball mill jar of the dispersed lead zirconate titanate ceramic powder slurry, and start ball milling dispersion. The ball mill speed is 150 rpm and the grinding time is 12 hours.

[0102] (4) After ball milling, the lead zirconate titanate ceramic powder slurry was filtered through a 200-mesh nylon filter cloth, and the viscosity was tested. After vacuum degassing for 2 hours, the viscosity was tested again. Then, casting began. The height of the scraper was controlled to obtain a 15μm cast film. The film surface was smooth, without scratches or pinholes, and the thickness was uniform.

[0103] The casting slurries and casting films prepared in the above eight embodiments are summarized in Table 1 with clearer parameters and results. The particle size of the ceramic powder was determined by statistically analyzing images taken with a scanning electron microscope, showing the average particle size of more than 150 particles. Viscosity was measured using a German Eikan viscometer, with the following testing methods: temperature 25℃, constant shear rate of 80 rpm / s, and testing time 180 s.

[0104] Example 9

[0105] The preparation process of the slurry and membrane in Example 9 is the same as in Example 1, except that in step (2), DOP with a mass of 2.4% of barium titanate formulation powder is weighed as a plasticizer.

[0106] Example 10

[0107] The preparation process of the slurry and membrane in this Example 10 is the same as that in Example 1, except that in step (2), DOP with a mass of 2.8% of barium titanate formulation powder is weighed as a plasticizer.

[0108] Example 11

[0109] The preparation process of the slurry and membrane in this Example 11 is the same as that in Example 1, except that in step (2), DOP with a mass of 3.0% of barium titanate formulation powder is weighed as a plasticizer.

[0110] Example 12

[0111] The preparation process of the slurry and membrane in this Example 12 is the same as that in Example 1, except that in step (2), DOP with a mass of 3.5% of barium titanate formulation powder is weighed as a plasticizer.

[0112] Example 13

[0113] The preparation process of the slurry and membrane in this Example 12 is the same as that in Example 1, except that in step (2), BM-2 type PVB with a mass of 6.0% of barium titanate formulation powder is weighed as binder, and DOP with a mass of 2.6% of barium titanate formulation powder is weighed as plasticizer. The mass ratio of PVB to DOP is 2.3, which is recorded as P / D = 2.3.

[0114] Example 14

[0115] The preparation process of the slurry and membrane in this Example 12 is the same as that in Example 1, except that in step (2), 7.0% of the mass of barium titanate formulation powder of BM-2 type PVB is weighed as binder, and 3.0% of the mass of barium titanate formulation powder of DOP is weighed as plasticizer. The mass ratio of PVB to DOP is 2.3, which is recorded as P / D = 2.3.

[0116] Example 15

[0117] The preparation process of the slurry and membrane in this Example 12 is the same as that in Example 1, except that in step (2), 8.0% of the mass of barium titanate formulation powder of BM-2 PVB is weighed as a binder and 3.5% of the mass of barium titanate formulation powder of DOP is weighed as a plasticizer. The mass ratio of PVB to DOP is 2.3, which is recorded as P / D = 2.3.

[0118] Comparative Example 1

[0119] A submicron ceramic dielectric powder casting slurry composition and its preparation method include the following steps:

[0120] (1) Powder dispersion: 500g of 0.3μm barium titanate formulation powder was added to a vertical stirred mill container. 1mm yttrium-stabilized zirconia balls were used as the grinding medium. AKM-0531 (1% by mass of barium titanate formulation powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (10.5% and 23.5% by mass of barium titanate formulation powder, respectively) were added as organic solvents. After weighing, dispersion began. The stirred mill speed was 2000 rpm, and the grinding time was 2 hours.

[0121] (2) Slurry dispersion: The dispersed barium titanate formulation powder slurry was poured into a ball mill jar. Then, BM-2 type PVB with a mass of 6.0% of the barium titanate formulation powder was added as a binder, and DOP with a mass of 2.4% of the barium titanate formulation powder was weighed as a plasticizer. Then, anhydrous ethanol and ethyl acetate with masses of 10.5% and 23.5% of the barium titanate formulation powder, respectively, were added as organic solvents. Ball milling dispersion was started, using 5 mm yttrium-stabilized zirconia balls as the grinding media, the ball mill speed was 120 rpm, and the grinding time was 16 h.

[0122] (3) After ball milling, the barium titanate formulation powder slurry was filtered through a 400-mesh nylon filter cloth, the viscosity was tested, and the foam was removed by vacuum for 1 hour. Then the viscosity was tested again, and then casting began. The height of the doctor blade was controlled to obtain a 6μm cast film.

[0123] Comparative Example 2

[0124] A submicron ceramic dielectric powder casting slurry composition and its preparation method include the following steps:

[0125] (1) Powder dispersion: 500g of 0.3μm barium titanate formulation powder was added to a vertical stirred mill container. 1mm yttrium-stabilized zirconia balls were used as the grinding medium. AKM-0531 (1% by mass of barium titanate formulation powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (10.5% and 23.5% by mass of barium titanate formulation powder, respectively) were added as organic solvents. After weighing, dispersion began. The stirred mill speed was 2000 rpm, and the grinding time was 2 hours.

[0126] (2) Adhesive preparation: In a beaker of a certain capacity, weigh 10.0% by mass of BM-2 type PVB barium titanate powder as a binder, weigh 4.0% by mass of DOP barium titanate powder as a plasticizer, and then add 10.5% and 23.5% by mass of anhydrous ethanol and ethyl acetate as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 1.5 hours.

[0127] (3) Slurry dispersion: Pour the dispersed barium titanate formulation powder slurry into a ball mill jar. Then, add the pre-prepared glue and start ball milling dispersion. Use 5mm yttrium-stabilized zirconia balls as the grinding medium, ball mill speed 120 rpm, grinding time 16h;

[0128] (4) After ball milling, the barium titanate formulation powder slurry was filtered through a 400-mesh nylon filter cloth, the viscosity was tested, and the foam was removed by vacuum for 1 hour. Then the viscosity was tested again, and then casting began. The height of the doctor blade was controlled to obtain a 6μm cast film.

[0129] Comparative Example 3

[0130] (1) Powder dispersion: 800g of 0.6μm lead zirconate titanate ceramic powder was added to a ball mill jar. 5mm yttrium-stabilized zirconia balls were used as the grinding medium. SC-0505K (1.0% by mass of lead zirconate titanate ceramic powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (12.5% ​​and 30% by mass of lead zirconate titanate ceramic powder, respectively) were added as organic solvents. After weighing, dispersion began at a ball mill speed of 150 rpm for 4 hours.

[0131] (2) Adhesive preparation: In a beaker of a certain capacity, weigh out 6.0% by weight of B76 type PVB (lead zirconate titanate powder) as a binder, weigh out 2.5% by weight of DOP (lead zirconate titanate powder) as a plasticizer, and then add 12.5% ​​and 30% by weight of anhydrous ethanol and ethyl acetate (lead zirconate titanate powder) as organic solvents, respectively. After weighing, begin dispersion, using a high-speed stirrer at 800 rpm for 2 hours.

[0132] (3) Slurry dispersion: Add the pre-prepared glue to the ball mill jar of the dispersed lead zirconate titanate ceramic powder slurry, and start ball milling dispersion. The ball mill speed is 150 rpm and the grinding time is 12 hours.

[0133] (4) After ball milling, the lead zirconate titanate ceramic powder slurry is filtered through a 200-mesh nylon filter cloth, the viscosity is tested, vacuum defoaming is performed for 2 hours, and the viscosity is tested again. Then, casting begins, and the height of the doctor blade is controlled to obtain a 15μm cast film.

[0134] Comparative Example 4

[0135] A submicron ceramic dielectric powder casting slurry composition and its preparation method include the following steps:

[0136] (1) Powder dispersion: 500g of 0.3μm barium titanate formulation powder was added to a vertical stirred mill container. 1mm yttrium-stabilized zirconia balls were used as the grinding medium. AKM-0531 (1% by mass of barium titanate formulation powder) was added as a dispersant. Then, anhydrous ethanol and ethyl acetate (7.5% and 20.0% by mass of barium titanate formulation powder, respectively) were added as organic solvents. After weighing, dispersion began at a stirred mill speed of 2000 rpm for 2 hours. After dispersion, the slurry was found to be too thick, adhering to the stirring rod and container wall, making it difficult to pour out.

[0137] (2) Adhesive preparation: In a beaker of a certain capacity, 6.0% by mass of BM-2 type PVB barium titanate powder was weighed as the binder, and 2.4% by mass of DOP barium titanate powder was weighed as the plasticizer. Then, 7.5% and 20.0% by mass of anhydrous ethanol and ethyl acetate barium titanate powder, respectively, were added as organic solvents. After weighing, dispersion was started. The speed of the high-speed stirrer was 800 rpm, and the stirring time was 2 hours. After stirring, it was found that the adhesive was too thick, the PVB was not completely dissolved, large lumps were present, and a large amount of adhesive was attached to the stirring plate.

[0138] Comparative Example 5

[0139] The composition and preparation method of the submicron ceramic media powder casting slurry in Comparative Example 5 are the same as those in Example 1, except that anhydrous ethanol is in excess, i.e., ethyl acetate: anhydrous ethanol = 1:2.

[0140] Comparative Example 6

[0141] The composition and preparation method of the submicron ceramic media powder casting slurry in Comparative Example 6 are the same as those in Example 1, except that: a small amount of anhydrous ethanol is used, i.e., ethyl acetate:anhydrous ethanol = 4:1.

[0142] Comparative Example 7

[0143] The composition and preparation method of the submicron ceramic media powder casting slurry in Comparative Example 7 are the same as those in Example 1, except that the plasticizer is present in small amounts, i.e., PVB:DOP = 1.5:1.

[0144] Comparative Example 8

[0145] The composition and preparation method of the submicron ceramic media powder casting slurry in Comparative Example 8 are the same as those in Example 1, except that the plasticizer is in excess, i.e., PVB:DOP = 3:1.

[0146] Table 1:

[0147]

[0148]

[0149] Table 2:

[0150]

[0151]

[0152] Comparative Example 1: Compared with Example 1, the effect of dissolving PVB first and then adding it is highlighted;

[0153] Comparative Example 2: Compared with Example 9, the PVB content is required to match the particle size.

[0154] Comparative Example 3: Compared with Example 6, the PVB content is required to match the particle size.

[0155] Comparative Example 4: Compared with Example 1, highlighting the effect of solvent content ratio;

[0156] Examples 1-3: Applicability and compatibility of the formulation with powders of different particle sizes (below 0.3 mm);

[0157] Examples 4-7: Applicability and compatibility of the formulation with powders of different compositions;

[0158] Examples 3 and 4; 6 and 8: Effect of PVB content on powders of different particle sizes;

[0159] Examples 9-12: The effect of DOP content (affecting P / D, mass ratio of binder to plasticizer) on powder performance;

[0160] Examples 13-15: Effect of PVB content (fixed P / D, varied DOP content) on powder performance.

[0161] The casting slurries prepared in the above embodiments can all produce high-quality cast films that meet the application requirements, proving that the present invention, while ensuring the quality of the cast films, is applicable to different submicron ceramic media powder systems and can prepare cast films of different thicknesses. Furthermore, in terms of film quality and experimental process, the ethanol and ethyl acetate system can replace toxic solvents such as toluene or acetone, optimizing the production environment and allowing casting work to be carried out in a more comfortable environment.

[0162] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method for preparing a submicron ceramic dielectric powder casting slurry, characterized in that, include: (1) Submicron-sized ceramic media powder, dispersant and part of organic solvent are mixed by ball milling or sand milling to obtain a slurry; (2) Mix the adhesive, plasticizer and another portion of the organic solvent to obtain the glue; (3) The obtained glue is added to the well dispersed slurry and then subjected to ball milling to obtain the submicron ceramic media powder casting slurry; When the average particle size of the submicron-sized ceramic powder is 0.1–0.3 μm as determined by scanning electron microscopy, the binder accounts for 5%–8% of the mass of the ceramic powder; when the average particle size of the submicron-sized ceramic powder is 0.3–0.6 μm as determined by scanning electron microscopy and does not include particles smaller than 0.3 μm, the binder accounts for 8%–12% of the mass of the ceramic powder and does not include particles smaller than 8 wt%. The organic solvent is composed of ethyl acetate and ethanol; wherein the mass ratio of ethyl acetate to ethanol is 2-3; and the mass ratio of the organic solvent to the submicron-sized ceramic powder is 60%-120%. The binder is polyvinyl butyral with a molecular weight between 40,000 and 120,000, and the mass ratio of the binder to the submicron-sized ceramic powder is 5% to 12%. The plasticizer is dioctyl phthalate (DOP), which is chemically pure; the mass ratio of the plasticizer to the submicron-sized ceramic powder is 2% to 4.5%; the mass ratio of the binder to the plasticizer is 1.6 to 2.

6.

2. The method for preparing submicron ceramic dielectric powder casting slurry according to claim 1, characterized in that, The submicron-sized ceramic powder comprises at least one of the following: barium titanate powder, lead zirconate titanate powder, barium calcium titanate powder, bismuth ferrite powder, sodium niobate powder, barium titanate powder doped with trace elements, lead zirconate titanate powder doped with trace elements, barium calcium titanate powder doped with trace elements, bismuth ferrite powder doped with trace elements, and sodium niobate powder doped with trace elements.

3. The method for preparing submicron ceramic dielectric powder casting slurry according to claim 2, characterized in that, The trace elements include at least one of Mn, Mg, Ca, Zr, V, Si, Y, and La; the doping amount of the trace elements does not exceed 3 at.

4. The method for preparing submicron ceramic dielectric powder casting slurry according to any one of claims 1-3, characterized in that, The particle size of the submicron-sized ceramic powder is: D as measured by a laser particle size analyzer. 50 The average particle size, measured by scanning electron microscopy, is between 0.1 and 0.6 μm, ranging from 0.2 to 0.8 μm; the moisture content of the submicron-sized ceramic powder is below 0.5 wt%.

5. The method for preparing submicron ceramic dielectric powder casting slurry according to any one of claims 1-3, characterized in that, The dispersant is an ammonium polycarboxylate salt; The mass ratio of the dispersant to the submicron-sized ceramic powder is 1% to 1.5%.

6. The method for preparing submicron ceramic dielectric powder casting slurry according to claim 5, characterized in that, The dispersant is selected from AKM-0531 or SC-0505K; the binder is at least one of BM-2, B-98 or B76.

7. The method for preparing submicron ceramic dielectric powder casting slurry according to any one of claims 1-3, characterized in that, The mass ratio of one part of the organic solvent to another part of the organic solvent is (30-70%): (70-30%).

8. The method for preparing submicron ceramic dielectric powder casting slurry according to any one of claims 1-3, characterized in that, The parameters of the ball milling process include: the grinding balls are yttrium-stabilized zirconia balls; the rotation speed is 120-150 rpm; and the time is 2-4 hours.

9. The method for preparing submicron ceramic dielectric powder casting slurry according to any one of claims 1-3, characterized in that, The parameters of the sand milling process include: the grinding balls are yttrium-stabilized zirconia balls; the rotation speed is 1000-2000 rpm; and the time is 2-4 hours.

10. The method for preparing submicron ceramic dielectric powder casting slurry according to any one of claims 1-3, characterized in that, A high-speed disperser is used to mix the adhesive during preparation; the high-speed disperser is a disc-shaped paddle; the speed of the high-speed disperser is 600-1000 rpm, and the time is 1-2 hours.

11. A method for preparing a cast film tape, characterized in that, The submicron ceramic medium powder casting slurry prepared by any one of the preparation methods of claims 1-10 is used to prepare the casting film tape by casting molding; the parameters of the casting molding include: the height of the doctor blade is 40-120 μm and the doctor blade speed is 0.5-2.0 cm / s.

12. A cast film tape, characterized in that, The casting film is prepared according to the preparation method described in claim 11; the film thickness of the casting film is 3-25 μm.

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