Low-temperature sintering and dielectric heat collaborative optimization method for zinc aluminate microwave dielectric ceramic

Abstract

The invention belongs to the field of microwave dielectric ceramic materials, and particularly provides a method for improving the performance of zinc aluminate microwave ceramic based on a SrF2-LiF composite sintering aid, so that the prepared zinc aluminate microwave dielectric ceramic material has low sintering temperature and high temperature change stability, and meanwhile, a low dielectric constant and a high quality factor are ensured; the method is suitable for manufacturing the ceramic substrate with excellent performance. According to the invention, a Zn0. 90Co0. 10Al2O4 system is adopted, the SrF2-LiF composite sintering aid is introduced, and the SrF2 and LiF compound is used as the sintering aid, so that the sintering temperature is effectively reduced, the uniform growth of crystal grains is promoted, the negative influence of high-temperature sintering on the material is reduced, and meanwhile, the density and the thermal stability of the ceramic are improved. Due to low-temperature sintering, the thermal expansion coefficient is reduced, the mechanical strength and the crack resistance are enhanced, and the material can be widely applied to the high-frequency microwave technology. According to the method, energy is saved, the production period is shortened, the dielectric property of the microwave ceramic is improved, and the microwave ceramic has wide application prospects in the fields of high-frequency microwave communication systems, electronic ceramic devices, high-strength ceramic substrates and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave dielectric ceramic materials, and particularly relates to a method for optimizing the low-temperature sintering and dielectric-thermal synergy of zinc aluminate microwave dielectric ceramics. Background Art

[0002] LTCC (Low Temperature Co-fired Ceramic) technology is a low-temperature co-fired ceramic technology widely used in the manufacture of electronic components. The main feature of LTCC technology is that it can co-fire and form a ceramic substrate and a metal electrode material at a relatively low temperature. This technology can simultaneously realize the integration of circuits and the structure of ceramic substrates, so it is widely used in high-frequency and high-reliability electronic products.

[0003] As a typical representative of spinel-structured microwave dielectric ceramics, zinc aluminate (ZnAl₂O₄) shows important application potential in 5G millimeter-wave communication, power electronic packaging, and aerospace wave-transparent devices due to its low dielectric constant, high thermal expansion coefficient, and excellent thermal stability. However, its industrial application faces two core challenges: one is that the traditional sintering temperature is too high, resulting in grain coarsening, increased porosity, and a sharp increase in dielectric loss, making it difficult to meet the requirements of high-frequency and low-loss; the other is the difficulty in synergistically regulating dielectric and thermal properties. For example, high thermal conductivity is not conducive to the heat dissipation of high-frequency devices, and traditional sintering aids (such as Bi₂O₃-SiO₂) can reduce the sintering temperature to 1300 °C, but they cause fluctuations in dielectric constant and CTE mismatch, leading to thermal stress delamination failure. Current research focuses on the design of composite sintering aids (such as LBSCA glass, CTN system) to achieve multi-objective optimization of "low-temperature sintering-dielectric-thermal synergy" to break through the performance bottleneck. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for improving the performance of zinc aluminate microwave ceramics based on SrF₂-LiF composite sintering aids, so that the prepared zinc aluminate microwave dielectric ceramic material has a low sintering temperature and good dielectric-thermal properties, and is suitable for manufacturing ceramic substrates with high thermal stability. The present invention adopts the Zn 0.90 Co 0.10 Al₂O₄ system, introduces SrF₂-LiF composite sintering aids, and optimizes the sintering and dielectric-thermal properties through multiple mechanisms. The SrF₂ and LiF complex as a sintering aid effectively reduces the sintering temperature, promotes the uniform growth of grains, reduces the negative impact of high-temperature sintering on the material, and at the same time improves the density and thermal stability of the ceramic. Low-temperature sintering also reduces the thermal expansion coefficient, enhances the mechanical strength and crack resistance, making the material more widely used in high-frequency microwave technology. This method not only saves energy and shortens the production cycle, but also improves the dielectric properties of microwave ceramics, making it have broad application prospects in fields such as high-frequency microwave communication systems, electronic ceramic devices, and high-strength ceramic substrates.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for low-temperature sintering and dielectric thermal synergistic optimization of zinc aluminate microwave dielectric ceramics, characterized by comprising the following steps:

[0007] a. Using ZnO (99%), CoO (99%) and Al2O3 (99%) as raw materials, and proportioning according to the stoichiometric ratio of the Zn 0.90 Co 0.10 Al2O4 molecular formula to prepare the main powder;

[0008] b. The main powder is ball-milled for the first time, taken out and dried after ball-milling, and the powder obtained after sieving is put into a sintering furnace, heated from room temperature to 1300 °C at a heating rate of 2 °C / min and held for 3 h, and then naturally cooled to room temperature with the furnace to obtain the main material;

[0009] c. Using LiF (99%) and SrF2 (99.7%) as raw materials, after mixing, ball-mill with deionized water for 12 hours. After drying and sieving, the sintering aid SrF2-LiF powder is obtained.

[0010] d. The SrF2-LiF composite sintering aid is added to the main material obtained in step b to form a powder, and then ball-milled for the second time, and then the second ball-milled material is taken out and dried.

[0011] e. The dried powder is uniformly mixed with polyvinyl alcohol (PVA) and pressed into a cylinder (Φ12 mm × h 6 mm).

[0012] f. The pressed cylindrical blank is held at 510 °C for 2 hours to remove PVA, and then heated to 1100 °C at a heating rate of 2 °C / min and sintered for 4 hours to obtain the optimized ZnAl2O4 microwave dielectric ceramic material sample.

[0013] Further, in steps b and d, the first ball-milling and the second ball-milling both adopt the same wet ball-milling. The wet ball-milling is carried out in a planetary ball mill, and deionized water is used as the solvent and iron balls are used as the ball-milling medium for wet ball-milling. Among them, the mass ratio of the raw material, the solvent and the iron balls is 1:1.5:2, the ball-milling time is 12 hours, and the ball-milling speed is 300 r / min.

[0014] Further, in step c, for the two sintering aid raw materials, weigh according to the optimal molar ratio of 2:8 and ball-mill with deionized water for 12 h.

[0015] Further, in steps b and d, the drying temperature is 80 °C and the drying time is 24 hours.

[0016] Further, in step d, the mass percentage of the sintering aid varies between 20% and 40 wt%, adjusting the sintering temperature and mechanical stability.

[0017] Further, in step e, the dosage of the binder is 12 wt%; the sieving process is as follows: passing through 40 mesh and 100 mesh in sequence, and taking the particles between 40 mesh and 100 mesh; the pressure for pressing into blocks is 15 Kg / cm 2 , and the time is 2 minutes, pressing into a cylindrical green body.

[0018] Based on the above technical solutions, the beneficial effects of the present invention are as follows:

[0019] The application of doping an appropriate amount of 0.2SrF2 - 0.8LiF in Zn 0.90 Co 0.10 Al2O4 microwave dielectric ceramics has significant beneficial effects. First, doping this material can effectively reduce the sintering temperature and improve the production efficiency of ceramics. Second, with the increase of the doping amount, the dielectric constant (εr) of the ceramics gradually decreases, optimizing its electrical properties to meet the requirements of microwave dielectric applications. In addition, the Q×f value shows a trend of first increasing and then decreasing when the doping amount is appropriate. Among them, when the sintering temperature is 1100 °C and the doping amount is 30 wt%, the Q×f value reaches 9695 GHz, indicating that the ceramics have a high quality factor and are suitable for high-frequency microwave applications. In terms of temperature stability, the τf value gradually shifts towards negative values, improving the temperature-frequency stability of the ceramics. Finally, the thermal expansion coefficient (CTE) of the ceramics reaches a maximum value of 12.02 ppm / °C, showing good thermal stability. These improvements have significantly enhanced the performance of Zn 0.90 Co 0.10 Al2O4 ceramics in microwave dielectric materials.

[0020] Figure 1 is the X-ray diffraction pattern of the zinc aluminate microwave dielectric ceramics sintered at 1100 °C in the invention example.

[0021] Figure 2 is the scanning electron microscope image of the zinc aluminate microwave dielectric ceramics sintered at 1100 °C in the invention example.

[0022] Figure 3 is the curve of the resonance frequency temperature coefficient varying with the doping amount of the zinc aluminate microwave dielectric ceramics sintered at 1100 °C in the invention example. Specific Embodiments

[0023] To make the objectives, technical solutions and beneficial effects of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0024] Example 1

[0025] This embodiment provides a method for improving the performance of zinc aluminate microwave ceramics based on a SrF2-LiF composite sintering aid. The chemical expression of the zinc aluminate microwave dielectric ceramics is: Zn 0.90 Co 0.10 Al2O4, specifically comprising the following steps:

[0026] a. Using ZnO (99%), CoO (99%) and Al2O3 (99%) as raw materials, according to Zn 0.90 Co 0.10 The main powder is prepared by mixing the ingredients in a stoichiometric ratio of the Al2O4 molecular formula;

[0027] b. Ball milling was performed once according to the mass ratio of main powder: water: iron ball = 1:1.5:2, the ball milling time was 12 hours, the ball milling speed was 300r / min, and the powder was taken out after ball milling and dried at 80℃. The powder obtained after drying and sifting was put into a sintering furnace, and the temperature was increased from room temperature to 1300℃ at a heating rate of 2℃ / min and kept at this temperature for 3 hours, and then naturally cooled to room temperature with the furnace to obtain the main material;

[0028] c. LiF (99%) and SrF2 (99.7%) were weighed at an optimal molar ratio of 2:8, and then the sintering aid was ball-milled with deionized water for 12 hours. After drying and sieving, the sintering aid SrF2-LiF powder was obtained.

[0029] d. Add SrF2-LiF composite sintering aid to the main material obtained in step b to prepare a powder, wherein the mass percentage of the sintering aid is 20wt%. Secondary ball milling is performed according to the mass ratio of main powder: water: iron ball = 1:1.5:2. The ball milling time is 12h and the ball milling speed is 300r / min. Then take out the secondary ball milled material and dry it at 80°C.

[0030] e. The dried powder was uniformly mixed with 12 wt% polyvinyl alcohol (PVA), and pressed into a cylinder (Φ12 mm×h 6 mm) at 20 MPa.

[0031] f. The pressed cylindrical body is kept at 510° C. for 2 hours to remove PVA, then heated to 1100° C. at a heating rate of 2° C. / min, and sintered for 4 hours to obtain the optimized ZnAl 2 O 4 microwave dielectric ceramic material sample.

[0032] The zinc aluminate microwave dielectric ceramic material prepared in this example was tested. The X-ray diffraction pattern is as follows: Figure 1 As shown in the figure, the crystallinity of ZnAl2O4 is good, and a small amount of SrF2 is also observed. Figure 2 As shown in the figure, the grain size distribution is obviously uneven, showing the coexistence of large grains and small grains. Figure 3As shown, the temperature stability coefficient of the resonant frequency is -3.9 ppm / °C. The dielectric constant is 5.91. The thermal expansion coefficient of the zinc aluminate microwave dielectric ceramic material in this example is 10.43. Q×f=6812 GHz.

[0033] Example 2

[0034] This embodiment provides a method for improving the performance of zinc aluminate microwave ceramics based on a SrF2-LiF composite sintering aid. The chemical expression of the zinc aluminate microwave dielectric ceramics is: Zn 0.90 Co 0.10 Al2O4, specifically comprising the following steps:

[0035] a. Using ZnO (99%), CoO (99%) and Al2O3 (99%) as raw materials, according to Zn 0.90 Co 0.10 The main powder is prepared by mixing the ingredients in a stoichiometric ratio of the Al2O4 molecular formula;

[0036] b. Ball milling was performed once according to the mass ratio of main powder: water: iron ball = 1:1.5:2, the ball milling time was 12 hours, the ball milling speed was 300r / min, and the powder was taken out after ball milling and dried at 80℃. The powder obtained after drying and sifting was put into a sintering furnace, and the temperature was increased from room temperature to 1300℃ at a heating rate of 2℃ / min and kept at this temperature for 3 hours, and then naturally cooled to room temperature with the furnace to obtain the main material;

[0037] c. LiF (99%) and SrF2 (99.7%) were weighed at an optimal molar ratio of 2:8, and then the sintering aid was ball-milled with deionized water for 12 hours. After drying and sieving, the sintering aid SrF2-LiF powder was obtained.

[0038] d. Add SrF2-LiF composite sintering aid to the main material obtained in step b to prepare a powder, wherein the mass percentage of the sintering aid is 25wt%. Secondary ball milling is performed in the mass ratio of main powder: water: iron ball = 1:1.5:2, the ball milling time is 12h, and the ball milling speed is 300r / min; then take out the secondary ball milled material and dry it at 80°C.

[0039] e. The dried powder was uniformly mixed with 12 wt% polyvinyl alcohol (PVA), and pressed into a cylinder (Φ12 mm×h 6 mm) at 20 MPa.

[0040] f. The pressed cylindrical body is kept at 510° C. for 2 hours to remove PVA, then heated to 1100° C. at a heating rate of 2° C. / min, and sintered for 4 hours to obtain the optimized ZnAl 2 O 4 microwave dielectric ceramic material sample.

[0041] The zinc aluminate microwave dielectric ceramic material prepared in this example was tested. The X-ray diffraction pattern is as follows: Figure 1 As shown in the figure, the crystallinity of ZnAl2O4 is good, and a small amount of SrF2 is also observed. Figure 2 As shown in the figure, the grain size distribution is obviously uneven, showing the coexistence of large grains and small grains, and large pores appear. Figure 3 As shown, the temperature stability coefficient of the resonant frequency is -17.1 ppm / °C. The dielectric constant is 5.87. The thermal expansion coefficient of the zinc aluminate microwave dielectric ceramic material in this example is 10.49. Q×f=8392 GHz.

[0042] Example 3

[0043] This embodiment provides a method for improving the performance of zinc aluminate microwave ceramics based on a SrF2-LiF composite sintering aid. The chemical expression of the zinc aluminate microwave dielectric ceramics is: Zn 0.90 Co 0.10 Al2O4, specifically comprising the following steps:

[0044] a. Using ZnO (99%), CoO (99%) and Al2O3 (99%) as raw materials, according to Zn 0.90 Co 0.10 The main powder is prepared by mixing the ingredients in a stoichiometric ratio of the Al2O4 molecular formula;

[0045] b. Ball milling was performed once according to the mass ratio of main powder: water: iron ball = 1:1.5:2, the ball milling time was 12 hours, the ball milling speed was 300r / min, and the powder was taken out after ball milling and dried at 80℃. The powder obtained after drying and sifting was put into a sintering furnace, and the temperature was increased from room temperature to 1300℃ at a heating rate of 2℃ / min and kept at this temperature for 3 hours, and then naturally cooled to room temperature with the furnace to obtain the main material;

[0046] c. LiF (99%) and SrF2 (99.7%) were weighed at an optimal molar ratio of 2:8, and then the sintering aid was ball-milled with deionized water for 12 hours. After drying and sieving, the sintering aid SrF2-LiF powder was obtained.

[0047] d. Add SrF2-LiF composite sintering aid to the main material obtained in step b to prepare a powder, wherein the mass percentage of the sintering aid is 30wt%. Secondary ball milling is performed at a mass ratio of main powder: water: iron ball = 1:1.5:2, the ball milling time is 12h, and the ball milling speed is 300r / min; then take out the secondary ball milled material and dry it at 80°C.

[0048] e. The dried powder was uniformly mixed with 12 wt% polyvinyl alcohol (PVA), and pressed into a cylinder (Φ12 mm×h 6 mm) at 20 MPa.

[0049] f. The pressed cylindrical body is kept at 510° C. for 2 hours to remove PVA, then heated to 1100° C. at a heating rate of 2° C. / min, and sintered for 4 hours to obtain the optimized ZnAl 2 O 4 microwave dielectric ceramic material sample.

[0050] The zinc aluminate microwave dielectric ceramic material prepared in this example was tested. The X-ray diffraction pattern is as follows: Figure 1 As shown in the figure, the crystallinity of ZnAl2O4 is good, and a small amount of SrF2 is also observed. Figure 2 As shown in Figure 2, the grain size tends to be uniform and the pores are reduced. Figure 3 As shown, the temperature stability coefficient of the resonant frequency is -18.51 ppm / °C. The dielectric constant is 5.75. The thermal expansion coefficient of the zinc aluminate microwave dielectric ceramic material in this example is 12.02. Q×f=9695 GHz.

[0051] Example 4

[0052] This embodiment provides a method for improving the performance of zinc aluminate microwave ceramics based on a SrF2-LiF composite sintering aid. The chemical expression of the zinc aluminate microwave dielectric ceramics is: Zn 0.90 Co 0.10 Al2O4, specifically comprising the following steps:

[0053] a. Using ZnO (99%), CoO (99%) and Al2O3 (99%) as raw materials, according to Zn 0.90 Co 0.10 The main powder is prepared by mixing the ingredients in a stoichiometric ratio of the Al2O4 molecular formula;

[0054] b. Ball milling was performed once according to the mass ratio of main powder: water: iron ball = 1:1.5:2, the ball milling time was 12 hours, the ball milling speed was 300r / min, and the powder was taken out after ball milling and dried at 80℃. The powder obtained after drying and sifting was put into a sintering furnace, and the temperature was increased from room temperature to 1300℃ at a heating rate of 2℃ / min and kept at this temperature for 3 hours, and then naturally cooled to room temperature with the furnace to obtain the main material;

[0055] c. LiF (99%) and SrF2 (99.7%) were weighed at an optimal molar ratio of 2:8, and then the sintering aid was ball-milled with deionized water for 12 hours. After drying and sieving, the sintering aid SrF2-LiF powder was obtained.

[0056] d. Add SrF2-LiF composite sintering aid to the main material obtained in step b to prepare a powder, wherein the mass percentage of the sintering aid is 35wt%. Secondary ball milling is performed in the mass ratio of main powder: water: iron ball = 1:1.5:2, the ball milling time is 12h, and the ball milling speed is 300r / min; then take out the secondary ball milled material and dry it at 80°C.

[0057] e. The dried powder was uniformly mixed with 12 wt% polyvinyl alcohol (PVA), and pressed into a cylinder (Φ12 mm×h 6 mm) at 20 MPa.

[0058] f. The pressed cylindrical body is kept at 510° C. for 2 hours to remove PVA, then heated to 1100° C. at a heating rate of 2° C. / min, and sintered for 4 hours to obtain the optimized ZnAl 2 O 4 microwave dielectric ceramic material sample.

[0059] The zinc aluminate microwave dielectric ceramic material prepared in this example was tested. The X-ray diffraction pattern is as follows: Figure 1 As shown in the figure, the crystallinity of ZnAl2O4 is good, and a small amount of SrF2 is also observed. Figure 2 As shown in Figure 1, some grains grow abnormally, resulting in an increase in the difference in grain size. Figure 3 As shown, the temperature stability coefficient of the resonant frequency is -26.12 ppm / °C. The dielectric constant is 5.53. The thermal expansion coefficient of the zinc aluminate microwave dielectric ceramic material in this example is 13.32. Q×f=8095 GHz.

[0060] Example 5

[0061] This embodiment provides a method for improving the performance of zinc aluminate microwave ceramics based on a SrF2-LiF composite sintering aid. The chemical expression of the zinc aluminate microwave dielectric ceramics is: Zn 0.90 Co 0.10 Al2O4, specifically comprising the following steps:

[0062] a. Using ZnO (99%), CoO (99%) and Al2O3 (99%) as raw materials, according to Zn 0.90 Co 0.10 The main powder is prepared by mixing the ingredients in a stoichiometric ratio of the Al2O4 molecular formula;

[0063] b. Ball milling was performed once according to the mass ratio of main powder: water: iron ball = 1:1.5:2, the ball milling time was 12 hours, the ball milling speed was 300r / min, and the powder was taken out after ball milling and dried at 80℃. The powder obtained after drying and sifting was put into a sintering furnace, and the temperature was increased from room temperature to 1300℃ at a heating rate of 2℃ / min and kept at this temperature for 3 hours, and then naturally cooled to room temperature with the furnace to obtain the main material;

[0064] c. Weigh LiF (99%) and SrF2 (99.7%) according to the optimal molar ratio of 2:8, and then ball-mill the sintering aid with deionized water for 12 hours. After drying and sieving, the SrF2-LiF powder of the sintering aid is obtained.

[0065] d. Add the SrF2-LiF composite sintering aid to the main material obtained in step b to form a powder material, where the mass percentage of the sintering aid is 40 wt%. Perform secondary ball-milling according to the ratio of the mass of the main powder: water: iron balls = 1:1.5:2, with a ball-milling time of 12 h and a ball-milling speed of 300 r / min; then take out the secondary ball-milled material and dry it at 80 °C.

[0066] e. Uniformly mix the dried powder material with 12 wt% polyvinyl alcohol (PVA) and press it into a cylinder (Φ12 mm × h 6 mm) under 20 MPa.

[0067] f. Keep the pressed cylindrical green body at 510 °C for 2 hours to remove PVA, then heat it up to 1100 °C at a heating rate of 2 °C / min and sinter for 4 hours to obtain the optimized ZnAl2O4 microwave dielectric ceramic material sample.

[0068] The zinc aluminate microwave dielectric ceramic material prepared in this example is tested. Among them, the X-ray diffraction pattern is as Figure 1 shown, the crystallinity of ZnAl2O4 is good, and the formation of a small amount of SrF2 is also observed. As Figure 2 shown, the abnormal growth of some grains leads to an increase in the grain size difference. As Figure 3 shown, the temperature stability coefficient of the resonance frequency is -26.98 ppm / °C. The dielectric constant is 5.32. The thermal expansion coefficient of the zinc aluminate microwave dielectric ceramic material in this example is 13.51. Among them, Q×f = 8875 GHz.

[0069] Through comparison, it is found that in Example 3, when the sintering temperature is 1100 °C and the mass percentage of the sintering aid is 30 wt%, the microstructure of the obtained sample is the most uniform and the performance is the best. The temperature stability coefficient of the resonance frequency is -18.51 ppm / °C, its dielectric constant is 5.75, Q×f = 9695 GHz, and the thermal expansion coefficient is 12.02 ppm / °C, indicating that the addition of the sintering aid not only reduces the sintering temperature, but also optimizes the temperature stability and thermal stability of the resonance frequency. At the same time, the dielectric properties and quality factor are also guaranteed.

[0070] The above are only specific embodiments of the present invention. Any feature disclosed in this specification, unless specifically described, can be replaced by other equivalent or alternative features with similar purposes; all the disclosed features, or all the steps in any method or process, except for mutually exclusive features and / or steps, can be combined in any manner.

Claims

1. A method for synergistic optimization of low-temperature sintering and dielectric heating of zinc aluminate microwave dielectric ceramics, characterized in that, It includes the following steps: a. Using ZnO (99%), CoO (99%) and Al2O3 (99%) as raw materials, according to the stoichiometric ratio of the Zn 0.90 Co 0.10 Al2O4 molecular formula for batching, the main powder is prepared; b. The main powder is ball-milled for the first time. After ball-milling, it is taken out and dried. The powder obtained after sieving is put into a sintering furnace and heated from room temperature to 1300 °C at a heating rate of 2 °C / min and held for 3 h, and then naturally cooled to room temperature with the furnace to obtain the main material; c. Using LiF (99%) and SrF2 (99.7%) as raw materials, after mixing, it is ball-milled with deionized water for 12 hours. After drying and sieving, the sintering aid SrF2-LiF powder is obtained. d. The SrF2-LiF composite sintering aid is added to the main material obtained in step b to form a powder, and then ball-milled for the second time, and then the second ball-milled material is taken out and dried. e. The dried powder is uniformly mixed with polyvinyl alcohol (PVA) and pressed into a cylinder (Φ12mm×h 6mm). f. The pressed cylindrical blank is held at 510 °C for 2 hours to remove PVA, and then heated to 1100 °C at a heating rate of 2 °C / min and sintered for 4 hours to obtain the optimized ZnAl2O4 microwave dielectric ceramic material sample.

2. The method for improving the performance of zinc aluminate microwave ceramics based on SrF2-LiF sintering aids according to claim 1, characterized in that, In steps b and d, the first ball-milling and the second ball-milling both adopt the same wet ball-milling. The wet ball-milling is carried out in a planetary ball mill, and wet ball-milling is carried out with deionized water as the solvent and iron balls as the ball-milling medium. Among them, the mass ratio of the raw material, the solvent and the iron balls is 1:1.5:2, the ball-milling time is 12 hours, and the ball-milling speed is 300 r / min.

3. The method for improving the properties of zinc aluminate microwave dielectric ceramics based on SrF2-LiF sintering aids according to claim 1, characterized in that In step c, for the two sintering aid raw materials, they are weighed according to the optimal molar ratio of 2:8 and ball-milled with deionized water for 12 h.

4. The method for improving the properties of zinc aluminate microwave dielectric ceramics based on SrF2-LiF sintering aids according to claim 1, wherein, In steps b and d, the drying temperature is 80 °C and the drying time is 24 hours.

5. The method for improving the properties of zinc aluminate microwave dielectric ceramics based on SrF2-LiF sintering aids according to claim 1, characterized in that, In step d, the mass percentage of the sintering aid varies between 20%-40 wt%, and the sintering temperature and dielectric thermal properties are adjusted.

6. The method for improving the properties of zinc aluminate microwave dielectric ceramics based on SrF2-LiF sintering aids according to claim 1, characterized in that, In step e, the dosage of the binder is 12 wt%; the sieving process is as follows: passing through 40-mesh and 100-mesh sieves in sequence, and taking the particles between 40-mesh and 100-mesh; the pressure for briquetting is 15 Kg / cm 2 , and the time is 2 minutes to press into a cylindrical green body.

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