A double-layer microwave dielectric ceramic material and a preparation method thereof

Abstract

This invention relates to the field of ceramic materials technology, specifically to a double-layer microwave dielectric ceramic material and its preparation method. The invention controls the shrinkage rate by increasing the pre-firing temperature, controlling the component lamination pressure, and controlling the sintering process, thus preparing a microwave dielectric ceramic material with a smooth surface and dense interior. This material not only retains the advantageous properties of each single-layer material, such as high dielectric constant and good temperature stability, but also achieves complementary and enhanced performance through the design of the lamination structure. This material not only possesses advantages such as high dielectric constant and high thermal stability, but also features a simple preparation process and low cost, thereby solving the problem of complex manufacturing processes and high production costs of existing double-layer microwave dielectric ceramic materials.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a double-layer microwave dielectric ceramic material and its preparation method. Background Technology

[0002] In microwave communication and radar systems, the performance requirements for microwave dielectric ceramic materials are becoming increasingly stringent. While traditional single-layer microwave dielectric ceramic materials possess certain dielectric constants, quality factors, and temperature coefficients, their performance often fails to meet practical needs in certain specialized applications, such as high-temperature, high-frequency, or high-power environments. In particular, the performance limitations of single-layer materials can lead to decreased microwave signal transmission efficiency, increased energy loss, and even system failure. Therefore, the practice of mixing ceramic powders of different systems to form solid solutions has emerged to improve performance. Ceramic solid solutions do indeed have unique advantages in improving the performance of microwave dielectric ceramic materials; for example, by adjusting the proportions of different components in the solid solution, key performance parameters such as dielectric constant, quality factor, and temperature coefficient can be optimized.

[0003] However, ceramic solid solutions also have some limitations. First, the preparation process of ceramic solid solutions is relatively complex, requiring precise control of the mixing ratio and sintering conditions of different ceramic powders. This not only increases production costs but may also lead to product performance instability due to slight differences in the preparation process. Second, when different powders are mixed to form a ceramic solid solution, different chemical substances have specific solubility limits in the solid solution. If these limits are exceeded, phase separation or other non-ideal structures may be formed, affecting the material's performance and stability. Furthermore, the crystal lattices of different compounds are often not perfectly matched, especially when the composition of the solid solution varies greatly. This may lead to lattice distortion, stress concentration, or grain boundary formation, affecting the material's mechanical properties and durability, etc. In addition, although the dielectric properties of ceramic solid solutions can be optimized by adjusting the component ratio, their performance may still be limited under certain extreme conditions, such as ultra-high temperature or ultra-high frequency environments. This is because different components in the solid solution may undergo phase transitions or changes in conductivity at high temperatures or high frequencies, thus affecting its overall performance.

[0004] Due to the potential incompatibility between crystal structure, ionic charge, and ionic radius, traditional random distribution processes inevitably lead to different defects. Summary of the Invention

[0005] The purpose of this invention is to provide a double-layer microwave dielectric ceramic material and its preparation method, aiming to solve the problems of complex manufacturing processes and high production costs of existing double-layer microwave dielectric ceramic materials.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a double-layer microwave dielectric ceramic material, comprising the following steps:

[0007] Prepare titanium dioxide, lanthanum oxide, sodium carbonate, samarium oxide, and lithium oxide, and dry them in an oven;

[0008] A first powder and a second powder are prepared based on the titanium dioxide, the lanthanum oxide, the sodium carbonate, the samarium oxide, and the lithium oxide;

[0009] 40g of the first powder was weighed and heated at 1050℃ for 2 hours to obtain the first main crystalline phase. 40g of the second powder was weighed and heated at 950℃ for 2 hours to obtain the second main crystalline phase.

[0010] Polyvinyl alcohol (8 wt%) was added to both the first and second main crystalline phases, and the mixture was ground for 1 hour, sieved, and then dried in an oven at 100°C for 6 hours to obtain Sm. 0.5 Li 0.5 TiO3 and La 0.5 Na 0.5 TiO3;

[0011] Weigh 1gSm 0.5 Li 0.5 After TiO3 is placed in a mold and pressed into shape, 1g of La is added. 0.5 Na 0.5 TiO3 was pressed for 4-5 minutes to obtain a laminated sheet;

[0012] The laminated sheet was sintered at 1250℃-1300℃ for 4 hours, and then cooled to 800℃ at a cooling rate of 50℃ / h before being naturally cooled to room temperature to obtain a laminated ceramic sheet.

[0013] The preparation of a first powder and a second powder based on the titanium dioxide, lanthanum oxide, sodium carbonate, samarium oxide, and lithium oxide includes:

[0014] The lanthanum oxide, sodium carbonate, and titanium dioxide are mixed in predetermined weights to obtain a first mixture;

[0015] The samarium oxide, lithium oxide, and titanium dioxide are mixed in predetermined weights to obtain a second mixture;

[0016] The first mixture and the second mixture were placed into a ball mill jar, and anhydrous ethanol was added to each mixture for ball milling to obtain a first slurry and a second slurry.

[0017] The first slurry and the second slurry are poured into beakers respectively and the alcohol is dried at a preset temperature to obtain a first powder and a second powder. The first powder and the second powder are then sieved.

[0018] In the section "mixing the lanthanum oxide, sodium carbonate, and titanium dioxide in preset weights to obtain a first mixture", the preset weight of the lanthanum oxide is 17.2852 g (±0.0005 g), the preset weight of the sodium carbonate is 5.6293 g (±0.0005 g), and the preset weight of the titanium dioxide is 17.1056 g (±0.0005 g).

[0019] In the section "mixing samarium oxide, lithium oxide and titanium dioxide in preset weights to obtain a second mixture", the preset weight of samarium oxide is 19.8968g (±0.0005g), the preset weight of lithium oxide is 1.7304g (±0.0005g), and the preset weight of titanium dioxide is 18.3966g (±0.0005g).

[0020] In the sentence “40g of the first powder is weighed and heated at 1050℃ for 2h to obtain the first main crystalline phase, and 40g of the second powder is weighed and heated at 950℃ for 2h to obtain the second main crystalline phase”, the heating rate of the first powder and the second powder is 2℃ / min.

[0021] In the section "sintering the laminated sheet at 1250℃-1300℃ for 4 hours, cooling the laminated sheet to 800℃ at a cooling rate of 50℃ / h, and then naturally cooling it to room temperature to obtain a laminated ceramic sheet", when the laminated sheet is heated to 500℃ and held at that temperature for 4 hours to remove the binder, the heating rate is 2℃ / min for the 20℃-550℃ range and 5℃ / min for the 55℃-1250℃ range.

[0022] Secondly, a double-layer microwave dielectric ceramic material is prepared using the double-layer microwave dielectric ceramic material preparation method described in the first aspect.

[0023] Including Sm 0.5 Li 0.5 TiO3 / La 0.5 Na 0.5 TiO3 stacked sheets.

[0024] A method for preparing a double-layer microwave dielectric ceramic material according to the present invention includes the following steps: preparing titanium dioxide, lanthanum oxide, sodium carbonate, samarium oxide, and lithium oxide, and drying them in an oven; preparing a first powder and a second powder based on the titanium dioxide, lanthanum oxide, sodium carbonate, samarium oxide, and lithium oxide; weighing 40g of the first powder and heating it at 1050℃ for 2h to obtain a first main crystalline phase; weighing 40g of the second powder and heating it at 950℃ for 2h to obtain a second main crystalline phase; adding 8wt% polyvinyl alcohol to the first main crystalline phase and the second main crystalline phase respectively, grinding for 1h, sieving, and drying in an oven at 100℃ for 6h to obtain Sm0.5 Li 0.5 TiO3 and La 0.5 Na 0.5 TiO3; Weigh 1g Sm 0.5 Li 0.5 After TiO3 is placed in a mold and pressed into shape, 1g of La is added. 0.5 Na 0.5 TiO3 was pressed for 4-5 minutes to obtain a laminated sheet; the laminated sheet was sintered at 1250℃-1300℃ for 4 hours, and then cooled to 800℃ at a cooling rate of 50℃ / h before being naturally cooled to room temperature to obtain a laminated ceramic sheet. This invention controls the shrinkage rate by increasing the pre-sintering temperature, controlling the component lamination pressure, and controlling the sintering process, thus preparing a microwave dielectric ceramic material with a smooth surface and dense interior. This material not only retains the advantages of each single-layer material, such as high dielectric constant and good temperature stability, but also achieves complementary and enhanced performance through the design of the laminated structure. This material not only has advantages such as high dielectric constant and high thermal stability, but also features a simple preparation process and low cost, thereby solving the problem of complex manufacturing processes and high production costs of existing double-layer microwave dielectric ceramic materials. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart of a method for preparing a double-layer microwave dielectric ceramic material provided by the present invention.

[0027] Figure 2 This is a flowchart of step S2.

[0028] Figure 3 It is La 0.5 Na 0.5 TiO3-Sm 0.5 Li 0.5 A schematic diagram of TiO3 microwave ceramic laminate.

[0029] Figure 4 This is a longitudinal scanning electron microscope image of SLT-LNT ceramic. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] Please see Figures 1 to 4 In a first aspect, the present invention provides a double-layer microwave dielectric ceramic material, comprising the following steps:

[0032] S1 prepares titanium dioxide, lanthanum oxide, sodium carbonate, samarium oxide, and lithium oxide, and puts them in an oven to dry;

[0033] Specifically, the required raw materials, such as titanium dioxide (99.0% purity), lanthanum oxide (99.9% purity), sodium carbonate (99.8%), samarium oxide (99.9% purity), and lithium oxide (99.99% purity), are placed in an oven at 100°C and dried for 24 hours.

[0034] S2 prepares a first powder and a second powder based on the titanium dioxide, the lanthanum oxide, the sodium carbonate, the samarium oxide, and the lithium oxide;

[0035] S21 mixes the lanthanum oxide, sodium carbonate and titanium dioxide in a predetermined weight to obtain a first mixture;

[0036] The preset weight of lanthanum oxide is 17.2852g (±0.0005g), the preset weight of sodium carbonate is 5.6293g (±0.0005g), and the preset weight of titanium dioxide is 17.1056g (±0.0005g).

[0037] Specifically, according to La 0.5 Na 0.5 The chemical formula of TiO3 is obtained by mixing 17.2852g (±0.0005g) lanthanum oxide, 5.6293g (±0.0005g) sodium carbonate, and 17.1056g (±0.0005g) titanium dioxide powder.

[0038] S22 mixes the samarium oxide, lithium oxide and titanium dioxide in a predetermined weight to obtain a second mixture;

[0039] The preset weight of samarium oxide is 19.8968g (±0.0005g), the preset weight of lithium oxide is 1.7304g (±0.0005g), and the preset weight of titanium dioxide is 18.3966g (±0.0005g).

[0040] Specifically, according to Sm 0.5 Li 0.5The chemical formula of TiO3 is obtained by mixing 19.8968g (±0.0005g) samarium oxide, 1.7304g (±0.0005g) lithium oxide, and 18.3966g (±0.0005g) titanium dioxide powder.

[0041] S23 The first mixture and the second mixture are respectively placed into a ball mill jar, and anhydrous ethanol is added to each mixture for ball milling to obtain a first slurry and a second slurry;

[0042] Specifically, the obtained mixed powders are placed into ball mill jars, and anhydrous ethanol is added as the milling medium. The sodium lanthanum titanate and lithium samarium titanate-based ceramic powders, zirconia balls, and anhydrous ethanol are mixed in a mass ratio of 1:2:1 to obtain a mixed product. The mixture is then ball-milled for 24 hours to ensure thorough and uniform mixing. After ball milling, a first slurry and a second slurry are obtained.

[0043] S24 The first slurry and the second slurry are poured into beakers respectively and the alcohol is dried at a preset temperature to obtain a first powder and a second powder, and the first powder and the second powder are sieved.

[0044] Specifically, pour the slurry into separate beakers and place them in an oven at 100℃~120℃ until the alcohol has completely evaporated. Grind the powders separately for 1 hour and then sieve them through a 100-mesh sieve.

[0045] S3 Weigh 40g of the first powder and heat it at 1050℃ for 2h to obtain the first main crystalline phase; weigh 40g of the second powder and heat it at 950℃ for 2h to obtain the second main crystalline phase.

[0046] The heating rate of the first powder and the second powder is 2℃ / min.

[0047] Specifically, to ensure good diameter matching in the prepared laminated sheets, La... 0.5 Na 0.5 TiO3 (40g), Sm 0.5 Li 0.5 TiO3 (40g) raw powder was pre-calcined at 1050℃ and 950℃ for 2h to form the main crystalline phase (heating rate 2℃ / min).

[0048] S4 adds 8 wt% polyvinyl alcohol to the first main crystalline phase and the second main crystalline phase, grinds for 1 hour, sieves, and then dries in a 100°C oven for 6 hours to obtain Sm. 0.5 Li 0.5 TiO3 and La 0.5 Na 0.5 TiO3;

[0049] Specifically, for the sintered La0.5 Na 0.5 TiO3, Sm 0.5 Li 0.5 Add 50-60 drops of polyvinyl alcohol (8 wt%) to TiO3 powder and grind for 1 hour to ensure thorough mixing of the powder and binder. After grinding, pass the resulting powder through a 100-mesh sieve and then dry it in a 100°C oven for 6 hours.

[0050] Weigh out 1g of Sm from S5. 0.5 Li 0.5 After TiO3 is placed in a mold and pressed into shape, 1g of La is added. 0.5 Na 0.5 TiO3 was pressed for 4-5 minutes to obtain a laminated sheet;

[0051] Specifically, weigh 1gSm 0.5 Li 0.5 Pour TiO3 into a mold, gently press the press head to pre-shape it, then add 1g of La 0.5 Na 0.5 TiO3 was pressed at 4 MPa for 4–5 minutes to obtain round tablets with a diameter of approximately 11 mm and a height of approximately 7 mm. The tableting process employed a split-die mold, which consisted of a pressure head, base, mold cavity, outer ring, and pressure-bearing pads. The mold cavity was placed on the base and secured with the outer ring before powder was added. Through multiple experiments, a pressure of 4 MPa for 4–5 minutes was selected to ensure the quality of the pressed tablets, resulting in green tablets with a smooth surface and no cracks. Removing the tablets simply involved separating the mold cavity from the outer ring, eliminating the need for demolding and preventing damage to the tablets caused by compression during demolding.

[0052] S6 sintersects the laminated sheet at 1250℃-1300℃ for 4 hours, then cools the laminated sheet to 800℃ at a cooling rate of 50℃ / h and then allows it to cool naturally to room temperature to obtain a laminated ceramic sheet.

[0053] When the laminated sheet is heated to 500°C and held at that temperature for 4 hours, the adhesive is discharged. The heating rate is 2°C / min for 20°C-550°C and 5°C / min for 55°C-1250°C.

[0054] Specifically, the obtained Sm 0.5 Li 0.5 TiO3 / La 0.5 Na 0.5After sintering the TiO3 laminated sheets at 1250℃~1300℃ for 4 hours, the temperature was controlled by a cooling rate of 50℃ / h, and then allowed to cool naturally to room temperature after reaching 800℃. The low cooling rate in the high-temperature zone effectively prevented problems such as bending and delamination during the sintering of dissimilar materials. During this process, the binder was removed by holding at 550℃ for 4 hours. The heating rate was 2℃ / min from 20℃ to 550℃ and 5℃ / min from 55℃ to 1250℃, finally yielding laminated ceramic sheets with a diameter of approximately 10mm and a height of 5mm. Compared with laminated ceramic sheets prepared using traditional cylindrical demolding molds, the resulting laminated sheets showed better performance, with intact surfaces and intermediate interfaces without cracks.

[0055] Table 1. EDS data of selected areas in SEM images.

[0056] Spectrum La(at%) Na(at%) Sm(at%) Ti(at%) O(at%) Spectrum Figure 4 1.52 5.42 6.23 15.57 71.26 Spectrum 5 4.53 5.08 4.65 17.46 68.28 Spectrum 7 1.59 4.78 7.14 16.40 70.09 Spectrum 9 2.86 4.77 6.45 17.48 68.44

[0057] The upper part of the SEM image belongs to Sm 0.5 Li 0.5 The TiO3 layer is below, while the La layer is below. 0.5 Na 0.5 TiO3 layer. Meanwhile, La... 3+ Na + and Sm 2+ Li + The diffusion within a certain range produces a dense intermediate layer, which acts as adhesive to bond the layers together and prevents the layers from aging.

[0058] Secondly, a double-layer microwave dielectric ceramic material is prepared using the double-layer microwave dielectric ceramic material preparation method described in the first aspect.

[0059] Including Sm 0.5 Li 0.5 TiO3 / La 0.5 Na 0.5 TiO3 stacked sheets.

[0060] Beneficial effects:

[0061] I. The layered structure design enables the material to have a wider frequency response range in the microwave band, exhibiting higher signal transmission efficiency and lower energy loss in microwave communication and radar systems. Because of the layered structure, good interfacial bonding can be formed between ceramic layers with different properties, thereby avoiding signal reflection and scattering during transmission and improving signal transmission efficiency. At the same time, the layered structure can also effectively reduce internal energy loss within the material, improving the overall performance of the system. Due to La... 0.5 Na 0.5 TiO3, Sm 0.5 Li 0.5TiO3 and TiO3 have different performance characteristics in the microwave frequency band. Combining them into a stacked structure can effectively broaden the frequency response range of the material, making it suitable for a wider range of applications.

[0062] Second, the layered structure also improves the dielectric properties and thermal stability of the material. Pure Sm 0.5 Li 0.5 TiO3 has a dielectric constant of approximately 52, while pure La... 0.5 Na 0.5 The dielectric constant of TiO3 is approximately 122, and the dielectric constant of the prepared multilayer microwave ceramic was found to be approximately 92.495 after testing. In microwave communication and radar systems, the temperature stability of materials is a crucial indicator. Through the design of the multilayer structure, microwave ceramics can maintain stable performance under different temperature conditions, thereby ensuring the reliability of the system in various environments. This temperature stability is significant for improving the long-term operational stability of the system and reducing maintenance costs. 0.5 Na 0.5 The temperature coefficient of the resonant frequency of TiO3 is generally around +480 ppm / ℃, while that of Sm 0.5 Li 0.5 The temperature coefficient of the resonant frequency of TiO3 is generally around -260ppm / ℃. After measuring the temperature coefficient of the prepared laminate, it was found to be approximately +200ppm / ℃, which also indicates that the design of the laminate structure achieves complementary and enhanced performance.

[0063] Third, when the proportion of raw materials in the laminated ceramic sheet is changed, its properties also change accordingly. For example, when using 1.2gSm... 0.5 Li 0.5 TiO3 and 0.8g La 0.5 Na 0.5 When preparing multilayer ceramics with TiO3, its dielectric constant decreased to 78.004 using 1.4g Sm 0.5 Li 0.5 TiO3 and 0.6g La 0.5 Na 0.5 When TiO3 is used to prepare multilayer ceramics, its dielectric constant decreases to 69.323, while using 0.8g Sm 0.5 Li 0.5 TiO3 and w1.2g La 0.5 Na 0.5 When preparing multilayer ceramics with TiO3, its dielectric constant is increased to 101.293 using 0.6g Sm 0.5 Li 0.5 TiO3 and 1.4g La 0.5 Na0.5 When TiO3 is used to prepare multilayer ceramics, its dielectric constant is increased to 107.672. This indicates that the proportion of each layer can be adjusted as needed to obtain better performance. By rationally selecting the pre-sintering temperature and co-sintering temperature of the materials, good matching in the diameter direction of the multilayer sheets was successfully achieved (e.g., ...). Figure 3 This method avoids cracking and performance degradation caused by mismatched shrinkage coefficients. Furthermore, each layer in the laminated structure can independently exhibit its superior properties, thereby improving the overall material performance. The preparation process is also simpler than that of ceramic solid solutions, eliminating the need for ball milling different ceramic powders and reducing preparation time. Finally, the preparation method for laminated microwave dielectric ceramic materials is simple, easy to implement, and inexpensive. By employing gradient heating and increasing holding time, optimization measures can ensure a more uniform distribution of thermal stress between the layers during sintering, reducing cracking and deformation. Simultaneously, this preparation method offers high controllability and repeatability, allowing for the convenient preparation of laminated microwave dielectric ceramic materials with different properties and structures.

[0064] The above description is merely a preferred embodiment of a double-layer microwave dielectric ceramic material and its preparation method according to the present invention. It should not be construed as limiting the scope of the present invention. Those skilled in the art can understand that implementing all or part of the above embodiments and making equivalent changes in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for preparing a double-layer microwave dielectric ceramic material, characterized in that, Includes the following steps: Prepare titanium dioxide, lanthanum oxide, sodium carbonate, samarium oxide, and lithium oxide, and dry them in an oven; A first powder is prepared based on the titanium dioxide, the lanthanum oxide, and the sodium carbonate; a second powder is prepared based on the titanium dioxide, the samarium oxide, and the lithium oxide. 40g of the first powder was weighed and heated at 1050℃ for 2 hours to obtain the first main crystalline phase. 40g of the second powder was weighed and heated at 950℃ for 2 hours to obtain the second main crystalline phase. Add 8 wt% polyvinyl alcohol to the first main crystalline phase, grind for 1 hour, sieve, and dry in a 100°C oven for 6 hours to obtain La. 0.5 Na 0.5 TiO3 was added to the second main crystalline phase with 8 wt% polyvinyl alcohol, ground for 1 hour, sieved, and then dried in a 100°C oven for 6 hours to obtain Sm. 0.5 Li 0.5 TiO3; Weigh 1gSm 0.5 Li 0.5 After TiO3 is placed in a mold and pressed into shape, 1g of La is added. 0.5 Na 0.5 TiO3 was pressed for 4-5 minutes to obtain a laminated sheet; The laminated sheet was sintered at 1250℃-1300℃ for 4 hours, and then cooled to 800℃ at a cooling rate of 50℃ / h before being naturally cooled to room temperature to obtain a laminated ceramic sheet.

2. The method for preparing a double-layer microwave dielectric ceramic material as described in claim 1, characterized in that, The process of "preparing a first powder based on the titanium dioxide, the lanthanum oxide, and the sodium carbonate, and preparing a second powder based on the titanium dioxide, the samarium oxide, and the lithium oxide" includes: A first mixture is obtained by mixing lanthanum oxide, sodium carbonate and titanium dioxide in a predetermined weight. A second mixture is obtained by mixing samarium oxide, lithium oxide, and titanium dioxide in predetermined weights. The first mixture and the second mixture were placed into a ball mill jar, and anhydrous ethanol was added to each mixture for ball milling to obtain a first slurry and a second slurry. The first slurry and the second slurry are poured into beakers respectively and the alcohol is dried at a preset temperature to obtain a first powder and a second powder. The first powder and the second powder are then sieved.

3. The method for preparing a double-layer microwave dielectric ceramic material as described in claim 2, characterized in that, In the phrase "mixing lanthanum oxide, sodium carbonate, and titanium dioxide in preset weights to obtain a first mixture", the preset weight of lanthanum oxide is 17.2852g ± 0.0005g, the preset weight of sodium carbonate is 5.6293g ± 0.0005g, and the preset weight of titanium dioxide is 17.1056g ± 0.0005g.

4. The method for preparing a double-layer microwave dielectric ceramic material as described in claim 2, characterized in that, In the phrase "mixing samarium oxide, lithium oxide, and titanium dioxide in preset weights to obtain a second mixture", the preset weight of samarium oxide is 19.8968g ± 0.0005g, the preset weight of lithium oxide is 1.7304g ± 0.0005g, and the preset weight of titanium dioxide is 18.3966g ± 0.0005g.

5. The method for preparing a double-layer microwave dielectric ceramic material as described in claim 1, characterized in that, In the statement "40g of the first powder was weighed and heated at 1050℃ for 2h to obtain the first main crystalline phase, and 40g of the second powder was weighed and heated at 950℃ for 2h to obtain the second main crystalline phase", the heating rate of the first powder and the second powder was 2℃ / min.

6. The method for preparing a double-layer microwave dielectric ceramic material as described in claim 1, characterized in that, In the process of "sintering the laminated sheet at 1250℃-1300℃ for 4 hours, cooling the laminated sheet to 800℃ at a cooling rate of 50℃ / h, and then naturally cooling it to room temperature to obtain a laminated ceramic sheet", when the laminated sheet is heated to 500℃ and held at that temperature for 4 hours to remove the binder, the heating rate is 2℃ / min for the 20℃-550℃ range and 5℃ / min for the 55℃-1250℃ range.

7. A double-layer microwave dielectric ceramic material, prepared by the method for preparing double-layer microwave dielectric ceramic materials according to any one of claims 1-6, characterized in that, Including Sm 0.5 Li 0.5 TiO3 / La 0.5 Na 0.5 TiO3 stacked sheets.

Images