Self-assembled superstructure ferrite-dielectric ceramic composite substrate and preparation method thereof

Abstract

The application relates to a self-assembled superstructure ferrite-dielectric ceramic composite substrate and a preparation method thereof. The preparation method comprises the following steps: screening ferrite powder and dielectric ceramic powder with required magnetic conductivity; dispersing the ferrite powder and the dielectric ceramic powder in water containing a binder and a crosslinking agent to obtain ceramic slurry; injecting the ceramic slurry into a trough of a casting machine, controlling the direction and strength of an applied magnetic field according to microsequence requirements; maintaining the strength of the magnetic field during the casting process, drying to remove excess water, and obtaining a single-layer composite ceramic substrate; stacking the single-layer composite ceramic substrates after cutting, vacuumizing and warm isostatic pressing, and obtaining a laminated casting sheet; cutting the laminated casting sheet into ceramic blanks, and obtaining the ferrite-dielectric ceramic composite substrate after drying, degreasing and sintering. The composite substrate improves the strength and integration degree, and reduces the applied working magnetic field strength of the composite substrate.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of high-performance substrate preparation for the electronic industry, and particularly relates to a self-assembled superstructure ferrite-dielectric ceramic composite substrate and a preparation method thereof. BACKGROUND

[0002] The ferrite-dielectric ceramic composite substrate is a new generation of microwave ceramic substrate, and can effectively improve the working frequency spectrum width and working power of communication equipment and is conducive to realizing millimeter wave communication because the ferrite can realize signal separation, filtering, transceiving and other functions of electronic components, so it is widely used in the fields of 5G communication, wireless monitoring, artificial intelligence and the like. The Y-type (Ba2Me2Fe 12 O 22 ) ferrite hexagonal material has very good application prospects in the millimeter wave field after being magnetized by an external magnetic field due to its extremely high magnetic crystal anisotropy and the characteristics of the easy magnetization plane in the vertical direction. However, a steady magnetic field with a magnetic field strength of 10,000 Oe or more is often needed to realize the Y-type ferrite at the present stage, and the generation conditions of the steady magnetic field with such a strength are extremely harsh, which leads to the difficulty of realizing wide frequency spectrum application of the equipment.

[0003] On the other hand, the current relatively advanced composite substrate is prepared by embedding and sealing the ferrite in the dielectric ceramic substrate to form an integrated substrate, but such a composite substrate often has problems such as serious sealing stress cracking, incomplete solder filling in the sealing area and fracture in the processing process, which leads to high production cost and limited component integration. SUMMARY

[0004] The main purpose of the application is to provide a preparation method of a self-assembled superstructure ferrite-dielectric ceramic composite substrate which can improve the strength of the composite substrate and reduce the required external magnetic field strength.

[0005] To achieve the above purpose, the technical scheme adopted by the application is as follows:

[0006] A preparation method of a self-assembled superstructure ferrite-dielectric ceramic composite substrate, comprising the following steps:

[0007] Step one, screening ferrite powder and dielectric ceramic powder with required magnetic conductivity, wherein the saturation magnetization of the ferrite powder is greater than that of the dielectric ceramic powder;

[0008] Step two, dispersing the ferrite powder and the dielectric ceramic powder in water containing a water-soluble binder and a crosslinking agent to obtain a ceramic slurry;

[0009] Step three, injecting the ceramic slurry into a trough of a flow coater, and controlling the direction and strength of the external magnetic field according to the microsequence requirement; the included angle between the direction of the magnetic field and the flow direction of the ceramic slurry is a first preset angle;

[0010] Step 4: The ceramic slurry flows out of the material tank onto the casting bed of the casting machine for casting. During the casting process, the ceramic slurry is dried to remove excess water from the ceramic slurry. The magnetic field strength is kept constant during the drying process. After drying, a self-assembled single-layer composite ceramic substrate of a certain thickness is obtained.

[0011] Step 5: Cutting the single-layer composite ceramic substrates and stacking them together, vacuuming and warm isostatic pressing are performed to obtain a laminated cast sheet;

[0012] Step 6: Cut the laminated cast sheet into ceramic green sheets of certain specifications and sizes. After drying, debinding and sintering, the ceramic green sheets are obtained to obtain a dense ferrite-dielectric ceramic composite substrate.

[0013] The saturation magnetization intensity of the ferrite powder is 8000 to 13000 Oe, and the specific surface area of ​​the ferrite powder is 10 to 15 g / m 2 , the particle size D of the ferrite powder 50 :0.05~0.5μm;

[0014] The specific surface area of ​​the dielectric ceramic powder is 10 to 15 g / m 2 , the particle size D of the dielectric ceramic powder 50 :0.05~0.5μm;

[0015] The saturation magnetization intensity of the ferrite powder is 9000 to 12000 Oe; the particle size D of the ferrite powder is 50 :0.1~0.3μm;

[0016] The particle size D of the dielectric ceramic powder 50 0.1~0.3μm.

[0017] The solid content of the ceramic slurry is 50-54 Vol%;

[0018] The viscosity of the ceramic slurry is 100 to 500 mPa·s;

[0019] The water-soluble binder is a water-based gel medium that is volatile and can help disperse the dielectric ceramic powder;

[0020] The cross-linking agent is ethylenediamine, diethylenetriamine or dipropylenetriamine.

[0021] The viscosity of the ceramic slurry is 100-200 mPa·s;

[0022] The binder is polyvinyl alcohol, acrylic acid-polyacrylic acid amine or acrylamide;

[0023] The mass ratio of the ferrite powder, dielectric ceramic powder, cross-linking agent and adhesive is (25-30):(25-30):1:(0.5-1);

[0024] The volume ratio of the ferrite powder and the dielectric ceramic powder is the same.

[0025] The direction of the magnetic field can be adjusted in space according to needs, and the first preset angle is 0-90°; the magnetic field strength is between 5,000 and 15,000 GS, and the saturation magnetization strength provided is 5,000 to 15,000 Oe.

[0026] The magnetic field strength is between 6,500 and 13,000 GS, providing a saturation magnetization strength of 6,500 to 13,000 Oe.

[0027] The thickness of the single-layer composite ceramic substrate is 15 to 20 μm;

[0028] The thickness of the laminated cast sheet is 0.8 to 1 mm;

[0029] The drying temperature on the casting bed is 60°C to 80°C, and the drying time is 5 to 15 minutes;

[0030] The drying is carried out in a blast oven at 60°C to 80°C for 8 to 12 hours;

[0031] The ceramic batch is a square substrate with a length and width of 1 to 2 inches, and a thickness of the square substrate is 0.8 to 1 mm.

[0032] The temperature rise curve during the debinding process is:

[0033]

[0034] Where RT is the room temperature during debinding; T1 is the drainage temperature; T2~T4 are the residual organic solvent ablation temperatures; T5 is the debinding temperature;

[0035] Among them, T1 is 150℃~200℃, T2 is 250℃~350℃, T3 is 400℃~450℃, T4 is 500℃~650℃, and T5 is 700℃~900℃;

[0036] The sintering temperature curve is:

[0037]

[0038] Among them, RT is the room temperature during sintering; T6 is the relatively low temperature section temperature; T7 is the high temperature sintering temperature; T6 is 150℃~200℃, T7 is 1200℃~1600℃, and the load during sintering is 0.04g / mm 2 .

[0039] The application also provides a self-assembled superstructure ferrite-dielectric ceramic composite substrate prepared according to the preparation method.

[0040] By the above technical solution, the application has at least the following advantages:

[0041] 1. The micro-order of the ferrite-dielectric ceramic composite substrate prepared by the application greatly improves the mechanical strength. According to GB / T 6569-2006, the bending strength of the composite ceramic is improved from 200 MPa to about 350 MPa.

[0042] 2. The application controls the orientation direction of the magnetic field during self-assembly. By controlling the magnetic field direction and the magnetic field strength, the magnetic field direction can be controlled at 90°, 30° or 45°, etc. to control the orientation of the ferrite powder part, reduce the saturation magnetic induction intensity of the ferrite powder, and thus reduce the required external magnetic field during the operation of the self-assembled composite substrate. The micro-order of the ferrite-dielectric ceramic composite substrate prepared by the application greatly reduces the required external magnetic field during operation. According to tests, the required magnetic field strength of the composite ceramic substrate during operation is reduced by 10% to 30%.

[0043] 3. The use of the flow casting and lamination method can effectively improve the content of the ferrite powder in the composite substrate. According to tests, the content of the ferrite powder is improved from 35% in the general nested structure to 50%. At the same time, the application controls the solid content in the ceramic slurry to control the assembly ratio of the self-assembled composite substrate, improve the ratio of the ferrite powder in the ferrite-dielectric ceramic, i.e. the assembly ratio, and improve the mechanical properties of the self-assembled composite substrate, which is not easy to crack during processing.

[0044] The above description is only a summary of the technical solutions of the application. In order to more clearly understand the technical means of the application and to implement the content of the description, the following describes the preferred embodiments of the application in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 Fig. 1 is a structural schematic diagram of a ferrite-dielectric ceramic composite substrate provided by an embodiment of the application;

[0046] Figure 2 Fig. 2 is another structural schematic diagram of a ferrite-dielectric ceramic composite substrate provided by an embodiment of the application. DETAILED DESCRIPTION

[0047] To further illustrate the technical means and effects employed by the present invention to achieve its intended objectives, the following detailed description of the specific embodiments, structures, features, and effects of the present invention is provided in conjunction with the accompanying drawings and preferred embodiments. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0048] like Figure 1 and Figure 2 As shown in the figure, a new generation of composite ceramic substrates using self-assembled metamaterials is used. An external magnetic field is pre-applied to the Y-type ferrite using a magnetic field induction method. Since the magnetic crystal planes of the Y-type ferrite will be oriented under the external magnetic field, and due to the different saturation magnetization intensities between the Y-type ferrite and the dielectric ceramic powder, and the anisotropy of the magnetic crystal plane of the ferrite, an orientation is generated, and finally the following is formed. Figure 1 and Figure 2 The microstructure of the ordered and controllable ferrite-dielectric ceramic composite substrate shown in the figure. The "sandwich" structure formed by ferrite 1 and dielectric ceramic 2 avoids stress cracking during the nested sealing process and provides a ferrite microstructure with oriented magnetic crystal planes. This significantly reduces the required operating magnetic field strength of the ferrite and significantly increases the ferrite content, ultimately enabling the miniaturization of electronic components.

[0049] The present invention will be further described below by means of specific embodiments:

[0050] Example 1

[0051] A method for preparing a self-assembled superstructure ferrite-dielectric ceramic composite substrate comprises the following steps:

[0052] Step 1: Screen out the saturation magnetization of 12000Oe and the specific surface area of ​​15g / m 2 , particle size D 50 The ferrite powder is 0.2μm and the specific surface area is 15g / m 2 , particle size D 50 0.2μm dielectric ceramic powder;

[0053] Step 2: Dispersing ferrite powder and dielectric ceramic powder in water containing a water-soluble binder and a cross-linking agent, wherein the mass ratio of ferrite powder: dielectric ceramic powder: binder: cross-linking agent is 25:25:1:1; obtaining a ceramic slurry with a viscosity of 150 mPa·s and a solid content of 50 Vol%;

[0054] The binder is polyvinyl alcohol;

[0055] The cross-linking agent is ethylenediamine;

[0056] Step 3: injecting the ceramic slurry into the trough of the tape casting machine, and controlling the direction and intensity of the external magnetic field according to the microscopic sequence requirements;

[0057] Control the direction and intensity of the applied magnetic field according to the microscopic sequence requirements. For example, if the applied magnetic field strength is insufficient or the working space is limited, the magnetic field strength should be increased in the 90° direction during the molding process to ensure the widest working window for the produced cast film.

[0058] When the applied magnetic field strength is sufficient but a narrow operating window is required, the magnetic field strength should be reduced to ensure that the produced cast film meets the required operating window. Modifying the magnetic field strength and direction, as long as there is a certain degree of order, ensures narrow-band operation within a limited space and a limited applied magnetic field. The magnetic field direction is at a certain angle to the casting direction of the ceramic slurry; preferably, it is at a 90° angle to the casting bed.

[0059] In this embodiment, an N-pole magnet is placed 0.5 m above the casting bed, and an S-pole magnet is placed 0.5 m below the casting bed. The line connecting the centers of the two magnets is perpendicular to the casting direction, that is, the angle between the line connecting the centers of the two magnets and the casting direction is 90°, that is, the direction of the magnetic field is 90° to the casting direction of the ceramic slurry; the magnetic field strength provided by the two magnets is 12000 GS, and the saturation magnetization strength provided is 12000 Oe.

[0060] Step 4: The ceramic slurry flows out of the material tank onto the casting bed of the casting machine for casting. During the casting process, the ceramic slurry is dried at 60°C for 10 minutes to remove excess water from the ceramic slurry. The magnetic field strength is kept constant at 8500GS during the drying process. During this process, the adhesive evaporates and the self-assembled ferrite-dielectric ceramic ordered sequence is self-assembled. After drying, a self-assembled single-layer composite ceramic substrate with a thickness of 18 μm is obtained; the thickness of the single-layer composite ceramic substrate is controlled by controlling the scraper height and / or the viscosity of the ceramic slurry;

[0061] Step 5: Cut the single-layer composite ceramic substrate into single-layer cast sheets with a length and width of 1 inch in the cutting area of ​​the casting bed, stack multiple single-layer cast sheets together, and perform vacuuming and warm isostatic pressing to obtain a laminated cast sheet with a thickness of 0.9 mm;

[0062] Step 6: drying the laminated cast sheet in a blast oven at 60° C. for 12 hours, debinding, and sintering to obtain a dense ferrite-dielectric ceramic composite substrate;

[0063] The maximum temperature of the debinding process does not exceed 900°C, and the temperature rise curve during the debinding process is:

[0064]

[0065] Where RT is the room temperature during debinding; T1 is the drainage temperature; T2~T4 are the residual organic solvent ablation temperatures; T5 is the debinding temperature;

[0066] Among them, T1 is 180℃, T2 is 330℃, T3 is 400℃, T4 is 550℃, and T5 is 800℃;

[0067] The sintering temperature curve is:

[0068]

[0069] Among them, RT is the room temperature during sintering; T6 is the relatively low temperature section temperature; T7 is the high temperature sintering temperature; T6 is 200℃, T7 is 1400℃, and the load during sintering is 0.04g / mm 2 .

[0070] Example 2

[0071] A method for preparing a self-assembled superstructure ferrite-dielectric ceramic composite substrate comprises the following steps:

[0072] Step 1: Screen out the saturation magnetization of 9000Oe and the specific surface area of ​​10g / m 2 , particle size D 50 Ferrite powder with a diameter of 0.3 μm and a specific surface area of ​​12 g / m 2 , particle size D 50 0.1μm dielectric ceramic powder;

[0073] Step 2: Disperse ferrite powder and dielectric ceramic powder in water containing a water-soluble binder and a cross-linking agent, wherein the mass ratio of ferrite powder: dielectric ceramic powder: binder: cross-linking agent is 25:25:1:0.5, to obtain a ceramic slurry with a viscosity of 200 mPa·s and a solid content of 52 Vol%;

[0074] The water-soluble binder is acrylic acid-polyacrylic acid amine;

[0075] The cross-linking agent is diethylenetriamine;

[0076] Step 3: injecting the ceramic slurry into the trough of the tape casting machine, and controlling the direction and intensity of the external magnetic field according to the microscopic sequence requirements;

[0077] Place an N-pole magnet directly above the casting bed and an S-pole magnet directly below the casting bed. The angle between the center of the two magnets and the casting direction is 85°. The magnetic field strength provided by the two magnets is 6500 GS, and the saturation magnetization provided is 6500 Oe.

[0078] Step 4: The ceramic slurry flows out of the material tank onto the casting bed of the casting machine for casting. During the casting process, the ceramic slurry is dried at 70°C for 15 minutes to remove excess water from the ceramic slurry. The magnetic field strength is kept constant at 6500GS during the drying process. During this process, the adhesive evaporates and the self-assembled ferrite-dielectric ceramic ordered sequence is self-assembled. After drying, a self-assembled single-layer composite ceramic substrate with a thickness of 20 μm is obtained.

[0079] Step 5: Cut the single-layer composite ceramic substrate into single-layer cast sheets with a length and width of 2 inches in the cutting area of ​​the casting bed, stack multiple single-layer cast sheets together, and perform vacuum pumping and warm isostatic pressing to obtain a laminated cast sheet with a thickness of 0.8 mm;

[0080] Step 6: drying the laminated cast sheet in a blast oven at 70° C. for 10 h, debinding, and sintering to obtain a dense ferrite-dielectric ceramic composite substrate;

[0081] The maximum temperature of the debinding process does not exceed 900°C, and the temperature rise curve during the debinding process is:

[0082]

[0083] Where RT is the room temperature during debinding; T1 is the drainage temperature; T2~T4 are the residual organic solvent ablation temperatures; T5 is the debinding temperature;

[0084] Among them, T1 is 200℃, T2 is 350℃, T3 is 450℃, T4 is 650℃, and T5 is 900℃;

[0085] The sintering temperature curve is:

[0086]

[0087] Among them, RT is the room temperature during sintering; T6 is the relatively low temperature section temperature; T7 is the high temperature sintering temperature; T6 is 180℃, T7 is 1200℃, and the load during sintering is 0.04g / mm 2 .

[0088] Example 3

[0089] A method for preparing a self-assembled superstructure ferrite-dielectric ceramic composite substrate comprises the following steps:

[0090] Step 1: Screen out the magnetic saturation intensity of 10000Oe and the specific surface area of ​​13g / m 2 , particle size D 50 Ferrite powder with a diameter of 0.1 μm and a specific surface area of ​​10 g / m 2 , particle size D 50 0.5μm dielectric ceramic powder;

[0091] Step 2: Disperse ferrite and dielectric ceramic powders in water containing a water-soluble binder and a crosslinking agent to form a ceramic slurry with a solid content of 54 Vol% and a viscosity of 500 mPa·s, wherein the mass ratio of ferrite: dielectric ceramic powder: crosslinking agent: binder is 30:30:1:1;

[0092] The water-soluble binder is acrylamide;

[0093] The cross-linking agent is dipropylene triamine;

[0094] Step 3: injecting the ceramic slurry into the trough of the tape casting machine, and controlling the direction and intensity of the external magnetic field according to the microscopic sequence requirements;

[0095] During the casting process, an N-pole magnet is placed at a height of 0.5 m above the casting bed, and an S-pole magnet is placed at a height of 0.5 m below the casting bed. The angle between the center of the two magnets and the casting direction is 45 degrees. The magnetic field strength provided by the two magnets is 10,000 GS, and the saturation magnetization intensity provided is 10,000 Oe.

[0096] Step 4: The ceramic slurry flows out of the material tank onto the casting bed of the casting machine for casting. During the casting process, the ceramic slurry is dried at 80°C for 5 minutes to remove excess water from the ceramic slurry. The magnetic field strength is kept constant at 10,000 GS during the drying process. During this process, the adhesive evaporates and the self-assembled ferrite-dielectric ceramic ordered sequence is self-assembled. After drying, a self-assembled single-layer composite ceramic substrate with a thickness of 15 μm is obtained.

[0097] Step 5: Cut the single-layer composite ceramic substrate into single-layer cast sheets with a length and width of 1.5 inches in the cutting area of ​​the casting bed, stack multiple single-layer cast sheets together, and obtain a laminated cast sheet with a thickness of 1.0 mm after vacuuming and warm isostatic pressing;

[0098] Step 6: drying the laminated cast sheet in a blast oven at 80° C. for 8 h, debinding, and sintering to obtain a dense ferrite-dielectric ceramic composite substrate;

[0099] The maximum temperature of the debinding process does not exceed 900°C, and the temperature rise curve during the debinding process is:

[0100]

[0101]

[0102] Where RT is the room temperature during debinding; T1 is the drainage temperature; T2~T4 are the residual organic solvent ablation temperatures; T5 is the debinding temperature;

[0103] Among them, T1 is 150℃, T2 is 250℃, T3 is 400℃, T4 is 500℃, and T5 is 700℃;

[0104] The sintering temperature curve is:

[0105]

[0106] Among them, RT is the room temperature during sintering; T6 is the relatively low temperature section temperature; T7 is the high temperature sintering temperature; T6 is 150℃, T7 is 1600℃, and the load during sintering is 0.04g / mm 2 .

[0107] Example 4

[0108] The preparation method of a self-assembled superstructure ferrite-dielectric ceramic composite substrate is basically the same as that of Example 1, except that:

[0109] In step 1: the magnetic saturation intensity of ferrite is 13000Oe, and the particle size of ferrite is D 50 :0.05μm; particle size D of dielectric ceramic powder 50 :0.3μm.

[0110] In step 2, the mass ratio of ferrite: dielectric ceramic powder: cross-linking agent: adhesive is 28:28:1:0.8.

[0111] In step 3: the magnetic field strength provided by the two magnets is 15000 GS, and the saturation magnetization provided is 15000 Oe.

[0112] Example 5

[0113] The preparation method of a self-assembled superstructure ferrite-dielectric ceramic composite substrate is basically the same as that of Example 1, except that:

[0114] In step 1: the magnetic saturation intensity of the ferrite is 8000 Oe;

[0115] In step 2, the mass ratio of ferrite: dielectric ceramic powder: cross-linking agent: adhesive is 27:27:1:0.6.

[0116] In step 3: the magnetic field strength provided by the two magnets is 5000 GS, the saturation magnetization provided is 5000 Oe, and the angle between the line connecting the centers of the two magnets and the casting direction is 90°.

[0117] Table 1 Performance comparison between each embodiment and existing magnesium titanate ceramic base

[0118]

[0119] As can be seen from Table 1, the magnetic field strength required for the present invention is lower than that required for conventional ceramic substrates. The applied magnetic field during the casting process in Example 5 was relatively small, resulting in incomplete alignment or suboptimal alignment. Therefore, the ferrite-dielectric ceramic composite substrate prepared in Example 5 requires a higher magnetic field strength for operation, reaching 11,000 GS. The present invention controls the orientation and stratification of the dielectric ceramic powder and ferrite powder during the casting process by controlling the strength and direction of the applied magnetic field, thereby controlling the stratification of the ferrite and dielectric ceramic, as well as the orientation of the ferrite magnetic surfaces. The closer the applied magnetic field strength in the perpendicular direction during casting approaches or exceeds the saturation magnetization of the ferrite powder, the more pronounced the ferrite alignment becomes, and the smaller the applied magnetic field required for the ferrite-dielectric ceramic composite substrate after sintering. Conventional ceramic substrates require a magnetic field strength no less than the saturation magnetization of the ferrite powder, whereas the preparation method of the present invention requires a magnetic field strength lower than the saturation magnetization of the ferrite powder. The present invention achieves the purpose of reducing the size of electronic components and improving the strength of the composite substrate through densification sintering. Further controlling the working magnetic field strength can widen the spectrum width, enabling the composite substrate to achieve wide-spectrum applications, and ultimately achieving the purpose of improving the mechanical strength, ferrite ratio and integration of the composite substrate, and reducing the strength of the external working magnetic field of the composite substrate.

[0120] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make slight changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a self-assembled superstructure ferrite-dielectric ceramic composite substrate, characterized in that: The following steps are involved: Step 1: Screening ferrite powder and dielectric ceramic powder whose magnetic conductivity meets the requirements, wherein the saturation magnetization intensity of the ferrite powder is greater than the saturation magnetization intensity of the dielectric ceramic powder; Step 2: dispersing ferrite powder and dielectric ceramic powder in water containing a water-soluble binder and a cross-linking agent to obtain a ceramic slurry; Step 3: injecting the ceramic slurry into the trough of the tape casting machine, and controlling the direction and intensity of the external magnetic field according to the microscopic sequence requirements; the angle between the magnetic field direction and the casting direction of the ceramic slurry is a first preset angle; The direction of the magnetic field can be adjusted in space as required, and the first preset angle is 0-90°; the magnetic field strength is between 5,000 and 15,000 Gs, and the saturation magnetization strength provided is 5,000 to 15,000 Oe; Step 4: The ceramic slurry flows out of the material tank onto the casting bed of the casting machine for casting. During the casting process, the ceramic slurry is dried to remove excess water from the ceramic slurry. The magnetic field strength is kept constant during the drying process. After drying, a self-assembled single-layer composite ceramic substrate of a certain thickness is obtained. Step 5: Cutting the single-layer composite ceramic substrates and stacking them together, vacuuming and warm isostatic pressing are performed to obtain a laminated cast sheet; Step 6: Cut the laminated cast sheet into ceramic green sheets of certain specifications and sizes. After drying, debinding and sintering, the ceramic green sheets are obtained to obtain a dense ferrite-dielectric ceramic composite substrate.

2. The preparation method according to claim 1, characterized in that The saturation magnetization intensity of the ferrite powder is 8000 to 13000 Oe, and the specific surface area of ​​the ferrite powder is 10 to 15 g / m 2 , the particle size D of the ferrite powder 50 :0.05~0.5μm; The specific surface area of ​​the dielectric ceramic powder is 10 to 15 g / m 2 , the particle size D of the dielectric ceramic powder 50 :0.05~0.5μm.

3. The preparation method according to claim 2, characterized in that The saturation magnetization intensity of the ferrite powder is 9000 to 12000 Oe; the particle size D of the ferrite powder is 50 :0.1~0.3μm; The particle size D of the dielectric ceramic powder 50 :0.1~0.3μm.

4. The preparation method according to claim 1, characterized in that The solid content of the ceramic slurry is 50-54 Vol%; The viscosity of the ceramic slurry is 100 to 500 mPa·s; The water-soluble binder is a volatile aqueous gel medium that can help disperse the dielectric ceramic powder; The cross-linking agent is ethylenediamine, diethylenetriamine or dipropylenetriamine.

5. The preparation method according to claim 4, characterized in that The viscosity of the ceramic slurry is 100-200 mPa·s; The binder is polyvinyl alcohol, acrylic acid-polyacrylic acid amine or acrylamide; The mass ratio of the ferrite powder, dielectric ceramic powder, cross-linking agent and adhesive is (25-30):(25-30):1:(0.5-1); The volume ratio of the ferrite powder and the dielectric ceramic powder is the same.

6. The preparation method according to any one of claims 1 to 5, characterized in that The magnetic field strength is between 6,500 and 13,000 Gs, and the saturation magnetization provided is between 6,500 and 13,000 Oe.

7. The preparation method according to any one of claims 1 to 5, characterized in that The thickness of the single-layer composite ceramic substrate is 15 to 20 μm; The thickness of the laminated cast sheet is 0.8 to 1 mm; The drying temperature on the casting bed is 60°C to 80°C, and the drying time is 5 to 15 minutes; The drying is carried out in a blast oven at 60°C to 80°C for 8 to 12 hours; The ceramic blank is a square substrate with a length and width of 1 to 2 inches, and a thickness of 0.8 to 1 mm.

8. The preparation method according to any one of claims 1 to 5, characterized in that The temperature rise curve during the debinding process is: Where RT is the room temperature during debinding; T1 is the drainage temperature; T2~T4 are the residual organic solvent ablation temperatures; T5 is the debinding temperature; Among them, T1 is 150℃~200℃, T2 is 250℃~350℃, T3 is 400℃~450℃, T4 is 500℃~650℃, and T5 is 700℃~900℃; The sintering temperature curve is: Among them, RT is the room temperature during sintering; T6 is the relatively low temperature section temperature; T7 is the high temperature sintering temperature; T6 is 150℃~200℃, T7 is 1200℃~1600℃, and the load during sintering is 0.04g / mm 2 .

9. A self-assembled superstructure ferrite-dielectric ceramic composite substrate, characterized in that: It is prepared according to the preparation method according to any one of claims 1 to 8.

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