Ceramic material for 5g dielectric filter and method for manufacturing the same

Abstract

The present application relates to a kind of ceramic materials for 5G medium filter and preparation method thereof.The chemical composition of the ceramic material for 5G medium filter is x CBZS glass-(1-x) Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3, wherein wt%≤x≤wt%;The composition of the CBZS glass includes: 40-60 mol% CaO, 10-25 mol% B2O3, 25-45 mol% ZnO, 10-20 mol% SiO2.

Description

Technical Field

[0001] This invention relates to a ceramic material suitable for 5G base station filters and its preparation method, specifically to a ceramic material for 5G dielectric filters and its preparation method, belonging to the field of electronic communication functional materials. Background Technology

[0002] Fifth-generation mobile communication technology (5G) is the latest generation of cellular mobile communication technology, an extension of 4G (LTE-A, WiMax), 3G (UMTS, LTE), and 2G (GSM) systems. The performance goals of 5G are high data rates, reduced latency, energy savings, lower costs, increased system capacity, and massive device connectivity. Radio frequency signals can be distorted by environmental interference at every stage of generation, conversion, and transmission, resulting in noise in the information carried by the signal. To eliminate noise and ensure radio frequency stability, filters are used in communication systems to remove noise interference, ensuring correct and effective communication. A filter is an electronic component that allows specific frequency components of a signal to pass through while significantly attenuating other frequency components.

[0003] Dielectric filters are characterized by their small size, high Q value, low insertion loss, good stability, and high power handling capacity. To meet the requirements of array antennas, 5G filters need to be smaller than 55×30×10mm, making them a promising mainstream solution in the 5G era. Furthermore, because dielectric filters use ceramic powder as raw material, their cost and selling price are lower than traditional cavity filters.

[0004] The filter requires the microwave dielectric material to have a near-zero temperature coefficient τ of resonant frequency. f A suitable dielectric constant ε r The ideal ceramic material for 5G dielectric filters requires a high quality factor (Q×f) of ≥50000GHz, the ability to be sintered densely at a relatively low temperature, and good compatibility with silver electrodes. Currently, the sintering temperature of ceramic materials for dielectric filters exceeds 1300℃, resulting in high energy consumption and a narrow sintering range, leading to increased filter costs and low yield rates, severely hindering the marketization of 5G dielectric filters. Therefore, finding suitable ceramic materials for 5G dielectric filters remains an important research topic in 5G technology. Summary of the Invention

[0005] Therefore, this invention provides a ceramic material for 5G dielectric filters and its preparation method. Specifically, this invention combines low-melting-point microcrystalline glass with microwave dielectric ceramics with good microwave dielectric properties. The resulting composite material meets the requirements of sintering below 1200℃ while possessing a tunable dielectric constant and a high Q value for 5G dielectric filters. The higher the Q value, the better the in-band insertion loss and out-of-band rejection of the filter, the more stable the performance, and the better the reliability.

[0006] On one hand, the present invention provides a ceramic material for 5G dielectric filters, wherein the chemical composition of the ceramic material for 5G dielectric filters is xCBZS glass-(1-x)Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3, of which 1.0 wt% ≤ x ≤ 30 wt%;

[0007] The composition of the CBZS glass includes: 40-60 mol% CaO, 10-25 mol% B2O3, 25-45 mol% ZnO, and 10-20 mol% SiO2.

[0008] Preferably, the concentrations are 1.0 wt% ≤ x ≤ 30 wt% and 15.0 wt% ≤ x ≤ 20 wt%. Within this range, the density is highest, the porosity is lowest, and the Qf value is highest at a sintering temperature of 1200℃. See Table 1 for detailed data.

[0009] Preferably, the molar percentage of B2O3, the molar percentage of ZnO, and the molar percentage of SiO2 in the CBZS glass are not zero.

[0010] Preferably, the microwave dielectric properties of the microwave ceramic material can be adjusted by changing the percentage mass ratio of microcrystalline glass to ceramic phase in the composite material: the dielectric constant of the ceramic material for the 5G dielectric filter is in the range of 17.2 to 21.0, the quality factor Q×f is 85000 to 100000, and the ideal resonant frequency temperature coefficient is 0.4 to 10.5 ppm / ℃.

[0011] On the other hand, the present invention provides a method for preparing ceramic materials for 5G dielectric filters, comprising:

[0012] (1) Preparation of CBZS glass powder;

[0013] (2) Preparation of Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05O3 ceramic powder;

[0014] (3) Mix CBZS glass powder and Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder is based on the chemical composition of ceramic materials used in 5G dielectric filters: xCBZS-(1-x)Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 is weighed and mixed, dried, and then a binder is added for granulation to obtain granulated powder.

[0015] (4) Press the granulated powder into a shape to obtain a green body;

[0016] (5) After debinding the blank, sinter it at 1100-1300℃ for 3-6 hours to obtain the ceramic material for the 5G dielectric filter.

[0017] In this invention, a ceramic material for 5G dielectric filters is prepared by compositing low-melting-point microcrystalline glass with microwave dielectric ceramics possessing excellent microwave dielectric properties. Specifically, the prepared glass powder and ceramic powder are mixed, dried, granulated, and pressed into shape according to a mass ratio, and then sintered at 1100–1300℃. The CBZS glass powder required in this invention can be obtained through traditional glass melting methods. Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder can be obtained through solid-state reaction. Because CBZS glass has a low Tg (720–850℃), it ensures that the composite material can be sintered densely below 1300℃. The ionic radii of Zn and Mg are close; excess Zn can dissolve and replace Mg ions, lowering the sintering temperature. Its crystalline phases are Zn₂SiO₄ (dielectric constant 6.5), CaSiO₃ (dielectric constant 5), and Ca₂B₂O₄ (dielectric constant 7). The dielectric constant of the material can be systematically reduced depending on the amount of precipitation. Additionally, Ca reacts with a trace amount of excess TiO₂ to form CaTiO₃, ε... r =170, Q×f=3000GHz and τ f =860ppm / ℃. According to the mixing principle of microwave dielectric properties of composite materials, the dielectric constant of the resulting composite material can be adjusted and is greater than 17. At the same time, the positive temperature coefficient of CaTiO3 can adjust the temperature coefficient of the entire system to approach zero.

[0018] In this invention, the microwave dielectric properties of the ceramic material for 5G dielectric filters can be adjusted by regulating the microcrystalline glass and ceramic phase: the optimal dielectric constant is 17.2 to 21.0, the quality factor Q×f is 45000 to 100000, preferably 85000 to 100000 GHz, and the temperature coefficient of resonant frequency is ±50 ppm / ℃, preferably 0.4 to 10.5 ppm / ℃. Moreover, the preparation process is simple and there are no pollutant emissions. It can be used in the manufacture of 5G dielectric filters and is a ceramic material for 5G dielectric filters with great potential application value.

[0019] Preferably, in step (1), the method for preparing the CBZS glass powder includes:

[0020] First, the Ca source, B source, Zn source and Si source are mixed in a molar ratio of (40-60):(10-25):(25-45):(10-20) to obtain raw material mixture A; then, raw material mixture A is melted and quenched to obtain glass fragments; finally, the glass fragments are ground, dried and sieved to obtain the CBZS glass powder.

[0021] Furthermore, preferably, the Ca source is CaCO3 with a purity greater than 99.5%, the B source is H3BO3 with a purity greater than 99.5%, the Zn source is ZnO with a purity greater than 99.5%, and the Si source is SiO2 with a purity greater than 99.5%.

[0022] Furthermore, preferably, the melting temperature is 1100–1300°C, and the melting time is 1–2 hours.

[0023] Preferably, in step (2), the Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The preparation methods of O3 ceramic powder include: first, according to Mg... 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 chemical formula: Mix Mg source, Ti source, Ca source, Zn source and Nb source to obtain raw material mixture B; then dry and sieve raw material mixture B to obtain precursor powder; finally, pre-calcine the precursor powder at 1100-1300℃ for 2-8 hours to obtain the Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder.

[0024] Furthermore, preferably, the Mg source is MgO with a purity greater than 99.5%; the Ti source is TiO2 with a purity greater than 99.5%; the Ca source is CaO with a purity greater than 99.5%; the Zn source is ZnO with a purity greater than 99.5%; and the Nb source is Nb2O5 with a purity greater than 99.9%.

[0025] Preferably, in step (3), the binder is at least one of a polyvinyl butyral solution of 8-10% by weight and a polyvinyl alcohol solution of 8-10% by weight; the binder is CBZS glass powder and Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The total mass of O3 ceramic powder is (10) mL: 1 g.

[0026] Preferably, in step (5), the temperature of the adhesive discharge is 400-600°C and the time is 1-4 hours.

[0027] Beneficial effects:

[0028] In this invention, the obtained ceramic material system for 5G dielectric filters has a dielectric constant of 17.2–21.0, a quality factor of 85,000–100,000 GHz, and a resonant frequency temperature coefficient of 0.4–10.5 ppm / ℃. While ensuring electrical performance meets filter requirements, the preparation process is simple, pollution-free, and low-cost. The sintering temperature of the ceramic material for 5G dielectric filters in this invention is lower than the commonly used sintering temperature of 1300℃. It exhibits uniform grain size, clear grain boundaries, low porosity, high density, and a water absorption rate of 0.01%. It is resistant to high and low temperature shocks, undergoing 100 cycles from -100℃ to +500℃ without cracking or ceramic chipping. It can be used in the manufacture of ceramics for 5G dielectric filters and is a ceramic material with significant potential application value. This invention employs a traditional solid-state synthesis process, uses chemical raw materials, has a low sintering temperature, is inexpensive, pollution-free, and facilitates mass production. Attached Figure Description

[0029] Figure 1 The XRD pattern of the ceramic material for the composite 5G dielectric filter prepared in Example 4;

[0030] Figure 2 The image shows a SEM image of the ceramic material used in the composite 5G dielectric filter prepared in Example 4. Detailed Implementation

[0031] 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.

[0032] In this disclosure, CaO-B2O3-ZnO-SiO2(CBZS) microcrystalline glass composite Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3Nb 2 / 3 ) 0.05 O3 ceramic is a ceramic material for 5G dielectric filters. The glass content ranges from 1.0 wt% to 30 wt%, and the ceramic content ranges from 99 wt% to 70 wt%. The composition of this 5G dielectric filter ceramic material is x CBZS-(1-x)Mg. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3, wherein 1.0 wt% ≤ x ≤ 30 wt%, the CBZS glass composition is 40-60 mol% CaO, 10-25 mol% B2O3 (preferably not zero), 25-45 mol% ZnO, and 10-20 mol% SiO2. Preferably, the CBZS glass composition is 43 mol% CaO - 15 mol% B2O3 - 30 mol% ZnO - 12 mol% SiO2. Wherein, Zn... 1 / 3 Nb 2 / 3 Its main components are ZnNb2O6 and Mg. 0.95 Ca 0.05 TiO3 has a high sintering temperature and a narrow range; therefore, this invention incorporates Zn doping. 1 / 3 Nb 2 / 3 The main purpose is to reduce the sintering temperature, broaden the sintering range, solve the problem of product overheating caused by the narrow range, and improve the product first pass rate.

[0033] In this invention, a ceramic material xCBZS-(1-x)Mg for 5G dielectric filters is obtained by compositing a low-melting-point microcrystalline glass with a microwave dielectric ceramic having good microwave dielectric properties. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3. In this invention, the center frequency of the 5G dielectric filter is 3.5GHz. According to design requirements, the dielectric constant of the microwave ceramic should range from 17.2 to 21.0, with a quality factor greater than 80000GHz, and the temperature coefficient of the resonant frequency should be close to zero ppm / ℃. The actual dielectric constant of this invention is 21, the test frequency is 6GHz, and the dielectric loss is 10. -5 Order of magnitude.

[0034] The following details the preparation of the ceramic material xCBZS-(1-x)Mg for 5G dielectric filters according to the present invention. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The method of O3.

[0035] In this invention, CBZS glass powder and Mg are obtained through both traditional glass melting and solid-state reaction methods. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder is mixed with glass powder and ceramic powder in the required mass ratio, dried, granulated, pressed into shape, and sintered at 1100-1300℃ to produce ceramic material for G dielectric filters.

[0036] In this invention, CBZS glass with a composition of 40-60 mol% CaO-10-25 mol% B2O3-25-45 mol% ZnO-10-20 mol% SiO2 is used as a microcrystalline glass. It has a low conversion temperature (720-850℃) and generates a liquid phase during the ceramic sintering process, thereby reducing the sintering temperature.

[0037] In this invention, CBZS glass powder can be prepared using a traditional glass melting method. Specifically, the process of preparing CBZS glass powder may include: calculating the required weight (wt%) of various raw materials according to the CBZS glass formulation (mol%), i.e., mixing C source (e.g., CaO), B source (e.g., B2O3), Zn source (e.g., ZnO), and Si source (e.g., SiO2) in a molar ratio of (40-60):(10-25):(25-45):(10-20) to obtain a raw material mixture; melting the raw material mixture and quenching it to obtain glass fragments; and grinding, drying, and sieving the glass fragments to obtain the CBZS glass powder. The purity of the raw materials used is greater than 99.5% to reduce the influence of impurities on the Q value. The melting temperature can be 1100-1300℃, preferably 1210℃; holding for 1.5 hours. An appropriate amount of water can be added before melting to ensure uniform mixing of the raw materials. During quenching, the molten glass can be quickly poured into a stainless steel bucket containing deionized water for quenching.

[0038] Glass fragments can be ground using ball milling. In the example, the obtained glass fragments are placed in an alumina ceramic jar in a certain ratio (e.g., material:ball:anhydrous ethanol = 1:3:2) and ball-milled for 1-2 hours to obtain an average particle size D. 50Glass powder with a particle size of approximately 1 ± 0.5 μm can be prepared by placing the ground glass powder slurry in a constant temperature drying oven (e.g., 120°C) and drying for 2–4 hours. After drying, the powder is sieved (e.g., through an 80-mesh sieve) to obtain the glass powder for later use.

[0039] In this invention, Mg is used 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder, as a microwave dielectric ceramic, possesses excellent microwave dielectric properties (ε). r =21.0, Q×f=100000GHz and τ f =4ppm / ℃). In this invention, CBZS glass and Zn doping are added. 1 / 3 Nb 2 / 3 Lowering the sintering temperature and expanding the sintering range, 1200℃ is the optimal sintering temperature, which is more than 100℃ lower than existing technologies, resulting in reduced energy consumption and a more environmentally friendly approach. During the sintering process, CBZS glass precipitates CaSiO3, which has a dielectric constant of 5, allowing for systematic adjustment of the material's dielectric constant. CBZS glass is a microcrystalline glass; the addition of ZnO precipitates Zn2SiO4, which reduces the ceramic's coefficient of thermal expansion, lowers the glass transition temperature, refines the ceramic grains, improves product strength, and prevents defects such as cracking caused by thermal shock, thus enhancing the reliability of the filter.

[0040] In this invention, Mg can be obtained through a solid-state reaction method. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder. Specifically, Mg is prepared. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The process of producing O3 ceramic powder may include: according to Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3Nb 2 / 3 ) 0.05O3 chemical formula: Mixing Mg source (e.g., magnesium oxide MgO), Ti source (titanium dioxide e.g., TiO2), Zn source (e.g., magnesium oxide ZnO), and Nb source (e.g., magnesium oxide Nb2O5) to obtain raw material mixture B; drying and sieving the raw material mixture B to obtain precursor powder; and pre-calcining the precursor powder at 1100–1300°C (e.g., 1200°C) for 2–8 hours (e.g., 5 hours) to obtain the Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder is prepared for later use. The purity of the raw materials used is greater than 99.5%. The raw materials can be mixed using ball milling. The mixture is added to a polyethylene tetrachloroethylene container in a certain ratio (e.g., material:ball:deionized water = 1:3:2), and ball-milled in a planetary ball mill for 1-2 hours to obtain the average particle size D. 50 The powder has a particle size of approximately 3 ± 0.5 μm. During drying, the ball-milled raw powder slurry can be placed in a constant temperature drying oven and dried at 110–140℃ for 2–4 hours. After drying, it can be sieved (e.g., a 40-mesh sieve) to obtain a uniformly mixed powder.

[0041] CBZS glass powder and Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder according to x CBZS-(1-x)Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 (1.0 wt% ≤ x ≤ 30 wt%) is mixed in a specific mass ratio. The mixing method can be ball milling. In one example, CBZS glass powder and Mg are mixed. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder is added to a polyethylene tetrachloro jar in a certain proportion (for example, the ratio of material:ball:anhydrous ethanol = 1:3:2), ball-milled in a planetary ball mill for 1-2 hours, and dried at 120°C for 3 hours. After drying, a uniformly mixed powder is obtained.

[0042] The mixture after ball milling is dried, a binder is added, granulation is performed, and the mixture is pressed into a green body. In this invention, the binder can be a polyvinyl butyral solution (PVB solution), polyvinyl alcohol (PVA) solution, etc., with a weight percentage of 8-10%. Furthermore, the mixture is sieved through a 20-mesh sieve before pressing.

[0043] After debinding the blank, it is sintered at a certain temperature to obtain the ceramic material xCBZS-(1-x)Mg for 5G dielectric filters. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3. The debinding temperature can be 400–600℃, and the time can be 1–4 hours. Sintering can be carried out in air at 1100–1300℃ for 3–6 hours. Then, the dielectric properties of the microwave dielectric ceramic material are tested.

[0044] Advantages of this invention:

[0045] The composite material of this invention can achieve sintering below 1200℃ while possessing a tunable dielectric constant greater than 17 and a Q value greater than 80000GHz. In this invention, the microwave dielectric properties of the low-temperature ceramic material can be adjusted by regulating the microcrystalline glass and ceramic phase: the optimal dielectric constant is 17.2–21.0, the quality factor is 85000–100000GHz, and the temperature coefficient of the resonant frequency is 0.4–10.5ppm / ℃. Furthermore, the preparation process is simple, pollution-free, and low-cost, making it suitable for manufacturing ceramics for 5G dielectric filters. It is a ceramic material for 5G dielectric filters with significant potential application value.

[0046] 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.

[0047] Test method:

[0048] (1) Phase Analysis (XRD): The composite sample was ground into a fine powder in an agate mortar and then tested on a Bruker D8 ADVANCE high-resolution powder X-ray diffractometer to obtain the XRD diffraction pattern. A copper target Kα beam was used, with a test voltage of 40 kV, a current of 40 mA, a scanning range of 10–80°, and a scanning speed of 10° / min. (2) Microwave Dielectric Properties: The relative permittivity ε of the sample at microwave frequencies was determined using the Hakki-Coleman open cylindrical network dielectric resonance method and the TE011 mode. r The quality factor Q×f was determined using an Agilent E8362B vector network analyzer. The test sample was a Φ12×6mm cylinder. The temperature coefficient of the resonant frequency of the sample was measured using a VT7004 oven with a test temperature range of 25~85℃.

[0049] Example 1:

[0050] (1) According to the CBZS glass ratio (mol%), weigh 36.99g CaCO3, 27.16g H3BO3, 27.35g ZnO and 20.36g SiO2, pour the prepared materials into a mortar, add an appropriate amount of deionized water and stir evenly. Then place it in a platinum crucible at 1210℃ and keep it warm for 1.5h. Then pour the molten glass directly into deionized water to quench and obtain a glass sample.

[0051] (2) Place 60g of glass fragments, 180g of zirconia balls, and 120mL of anhydrous ethanol obtained in step (1) into an alumina ceramic jar and ball mill them for 3h in a planetary ball mill at a speed of 350r / min.

[0052] (3) Place the ball-milled glass powder slurry from step (2) in a 120℃ constant temperature drying oven and dry for 3 hours. After drying, pass it through an 80-mesh sieve to obtain glass powder (particle size D). 50 (≈1±0.5μm) for later use;

[0053] (4) According to Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The chemical formula for O3 is as follows: weigh out 30.61g MgO, 60.67g TiO2, 4.00g CaCO3, 1.11g ZnO, and 3.61g Nb2O5, totaling 100g; add 100g of material, 450g of zirconia balls, and 300mL of deionized water into a polyethylene tetrachloroethylene container, and ball mill in a planetary ball mill at 350r / min for 1h;

[0054] (5) Place the raw powder slurry that was ball-milled in step (4) into a constant temperature drying oven and dry it at 120°C for 3 hours. After drying, pass it through a 40-mesh sieve to obtain a uniformly mixed powder.

[0055] (6) Place the powder after sieving in step (5) into a muffle furnace and pre-calcine it at 1200℃ for 5 hours to obtain Mg. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder (particle size D) 50 (≈3±0.5μm) for later use;

[0056] (7) Mix 1.0g of CBZS glass powder and 99g of Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder mixture, 100g in total; add 100g of material + 300g of zirconia balls + 200mL of anhydrous ethanol into a polyethylene tetrachloroethylene tank, and ball mill in a planetary ball mill at 350r / min for 1h; after drying at 120℃, add 8% by weight of PVA solution as a binder for granulation, pass through a 20-mesh sieve, and then compress into tablets.

[0057] (8) The sample from step (7) was placed in a muffle furnace, and the binder was removed at 500°C for 2 hours. The sample was then sintered at 1350°C in air for 3 hours to produce a ceramic sample block for a 5G dielectric filter.

[0058] The microwave dielectric properties of the sample obtained in this example were measured using the Hakki-Coleman open cylindrical network dielectric resonance method, employing the TE011 mode to determine the relative permittivity ε of the sample at the microwave frequency. r The quality factor Q×f was determined using an Agilent E8362B vector network analyzer. The test sample was a Φ12×6mm cylinder. The temperature coefficient of the resonant frequency of the sample was measured using a VT7004 oven with a test temperature range of 25~85℃.

[0059] Example 2:

[0060] (1) According to the CBZS glass ratio (mol%), weigh 36.99g CaCO3, 27.16g H3BO3, 27.35g ZnO and 20.36g SiO2, pour the prepared materials into a mortar, add an appropriate amount of deionized water and stir evenly. Then place it in a platinum crucible at 1210℃ and keep it warm for 1.5h. Then pour the molten glass directly into deionized water to quench and obtain a glass sample.

[0061] (2) Place 60g of glass fragments, 180g of zirconia balls, and 120mL of anhydrous ethanol obtained in step (1) into an alumina ceramic jar and ball mill them for 3h in a planetary ball mill at a speed of 350r / min.

[0062] (3) Place the ball-milled glass powder slurry from step (2) in a 120℃ constant temperature drying oven and dry for 3 hours. After drying, pass it through an 80-mesh sieve to obtain glass powder (particle size D). 50 (≈1±0.5μm) for later use;

[0063] (4) According to Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The chemical formula for O3 is as follows: weigh out 30.61g MgO, 60.67g TiO2, 4.00g CaCO3, 1.11g ZnO, and 3.61g Nb2O5, totaling 100g; add 100g of material, 450g of zirconia balls, and 300mL of deionized water into a polyethylene tetrachloroethylene container, and ball mill in a planetary ball mill at 350r / min for 1h;

[0064] (5) Place the raw powder slurry that was ball-milled in step (4) into a constant temperature drying oven and dry it at 120°C for 3 hours. After drying, pass it through a 40-mesh sieve to obtain a uniformly mixed powder.

[0065] (6) Place the powder after sieving in step (5) into a muffle furnace and pre-calcine it at 1200℃ for 5 hours to obtain Mg. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder (particle size D) 50 (≈3±0.5μm) for later use;

[0066] (7) Mix 5.0g of CBZS glass powder and 95.0g of Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder mixture, 100g in total; add 100g of material + 300g of zirconia balls + 200mL of anhydrous ethanol into a polyethylene tetrachloroethylene tank, and ball mill in a planetary ball mill at 350r / min for 1h; after drying at 120℃, add 8% by weight of PVA solution as a binder for granulation, pass through a 20-mesh sieve, and then compress into tablets.

[0067] (8) The sample from step (7) was placed in a muffle furnace, debinded at 500°C for 2 hours, and sintered at 1300°C in air for 3 hours to produce a ceramic sample block for a 5G dielectric filter. The microwave dielectric properties of the sample obtained in this embodiment were tested using a network analyzer and related test fixtures.

[0068] Example 3:

[0069] (1) According to the CBZS glass ratio (mol%), weigh 36.99g CaCO3, 27.16g H3BO3, 27.35g ZnO and 20.36g SiO2, pour the prepared materials into a mortar, add an appropriate amount of deionized water and stir evenly. Then place it in a platinum crucible at 1210℃ and keep it warm for 1.5h. Then pour the molten glass directly into deionized water to quench and obtain a glass sample.

[0070] (2) Place 60g of glass fragments, 180g of zirconia balls, and 120mL of anhydrous ethanol obtained in step (1) into an alumina ceramic jar and ball mill them for 3h in a planetary ball mill at a speed of 350r / min.

[0071] (3) Place the ball-milled glass powder slurry from step (2) in a 120℃ constant temperature drying oven and dry for 3 hours. After drying, pass it through an 80-mesh sieve to obtain glass powder (particle size D). 50 (≈1±0.5μm) for later use;

[0072] (4) According to Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The chemical formula for O3 is as follows: weigh out 30.61g MgO, 60.67g TiO2, 4.00g CaCO3, 1.11g ZnO, and 3.61g Nb2O5, totaling 100g; add 100g of material, 450g of zirconia balls, and 300mL of deionized water into a polyethylene tetrachloroethylene container, and ball mill in a planetary ball mill at 350r / min for 1h;

[0073] (5) Place the raw powder slurry that was ball-milled in step (4) into a constant temperature drying oven and dry it at 120°C for 3 hours. After drying, pass it through a 40-mesh sieve to obtain a uniformly mixed powder.

[0074] (6) Place the powder after sieving in step (5) into a muffle furnace and pre-calcine it at 1200℃ for 5 hours to obtain Mg. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05O3 ceramic powder (particle size D) 50 (≈3±0.5μm) for later use;

[0075] (7) Mix 10.0g of CBZS glass powder and 90.0g of Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder mixture, 100g in total; add 100g of material + 300g of zirconia balls + 200mL of anhydrous ethanol into a polyethylene tetrachloroethylene tank, and ball mill in a planetary ball mill at 350r / min for 1h; after drying at 120℃, add 8% by weight of PVA solution as a binder for granulation, pass through a 20-mesh sieve, and then compress into tablets.

[0076] (8) The sample from step (7) was placed in a muffle furnace, debinded at 500°C for 2 hours, and sintered at 1250°C for 3 hours in air atmosphere to produce a ceramic sample block for a 5G dielectric filter. The microwave dielectric properties of the sample obtained in this embodiment were tested using a network analyzer and related test fixtures.

[0077] Example 4:

[0078] (1) According to the CBZS glass ratio (mol%), weigh 36.99g CaCO3, 27.16g H3BO3, 27.35g ZnO and 20.36g SiO2, pour the prepared materials into a mortar, add an appropriate amount of deionized water and stir evenly. Then place it in a platinum crucible at 1210℃ and keep it warm for 1.5h. Then pour the molten glass directly into deionized water to quench and obtain a glass sample.

[0079] (2) Place 60g of glass fragments, 180g of zirconia balls, and 120mL of anhydrous ethanol obtained in step (1) into an alumina ceramic jar and ball mill them for 3h in a planetary ball mill at a speed of 350r / min.

[0080] (3) Place the ball-milled glass powder slurry from step (2) in a 120℃ constant temperature drying oven and dry for 3 hours. After drying, pass it through an 80-mesh sieve to obtain glass powder (particle size D). 50 (≈1±0.5μm) for later use;

[0081] (4) According to Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05The chemical formula for O3 is as follows: weigh out 30.61g MgO, 60.67g TiO2, 4.00g CaCO3, 1.11g ZnO, and 3.61g Nb2O5, totaling 100g; add 100g of material, 450g of zirconia balls, and 300mL of deionized water into a polyethylene tetrachloroethylene container, and ball mill in a planetary ball mill at 350r / min for 1h;

[0082] (5) Place the raw powder slurry that was ball-milled in step (4) into a constant temperature drying oven and dry it at 120°C for 3 hours. After drying, pass it through a 40-mesh sieve to obtain a uniformly mixed powder.

[0083] (6) Place the powder after sieving in step (5) into a muffle furnace and pre-calcine it at 1200℃ for 5 hours to obtain Mg. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder (particle size D) 50 (≈3±0.5μm) for later use;

[0084] (7) Mix 15.0g of CBZS glass powder and 85.0g of Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder mixture, 100g in total; add 100g of material + 300g of zirconia balls + 200mL of anhydrous ethanol into a polyethylene tetrachloroethylene tank, and ball mill in a planetary ball mill at 350r / min for 1h; after drying at 120℃, add 8% by weight of PVA solution as a binder for granulation, pass through a 20-mesh sieve, and then compress into tablets.

[0085] (8) The sample from step (7) was placed in a muffle furnace, debinded at 500°C for 2 hours, and sintered at 1200°C for 3 hours in air atmosphere to produce a ceramic sample block for a 5G dielectric filter. The microwave dielectric properties of the sample obtained in this embodiment were tested using a network analyzer and related test fixtures.

[0086] Example 5:

[0087] (1) According to the CBZS glass ratio (mol%), weigh 36.99g CaCO3, 27.16g H3BO3, 27.35g ZnO and 20.36g SiO2, pour the prepared materials into a mortar, add an appropriate amount of deionized water and stir evenly. Then place it in a platinum crucible at 1210℃ and keep it warm for 1.5h. Then pour the molten glass directly into deionized water to quench and obtain a glass sample.

[0088] (2) Place 60g of glass fragments, 180g of zirconia balls, and 120mL of anhydrous ethanol obtained in step (1) into an alumina ceramic jar and ball mill them for 3h in a planetary ball mill at a speed of 350r / min.

[0089] (3) Place the ball-milled glass powder slurry from step (2) in a 120℃ constant temperature drying oven and dry for 3 hours. After drying, pass it through an 80-mesh sieve to obtain glass powder (particle size D). 50 (≈1±0.5μm) for later use;

[0090] (4) According to Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The chemical formula for O3 is as follows: weigh out 30.61g MgO, 60.67g TiO2, 4.00g CaCO3, 1.11g ZnO, and 3.61g Nb2O5, totaling 100g; add 100g of material, 450g of zirconia balls, and 300mL of deionized water into a polyethylene tetrachloroethylene container, and ball mill in a planetary ball mill at 350r / min for 1h;

[0091] (5) Place the raw powder slurry that was ball-milled in step (4) into a constant temperature drying oven and dry it at 120°C for 3 hours. After drying, pass it through a 40-mesh sieve to obtain a uniformly mixed powder.

[0092] (6) Place the powder after sieving in step (5) into a muffle furnace and pre-calcine it at 1200℃ for 5 hours to obtain Mg. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder (particle size D) 50 (≈3±0.5μm) for later use;

[0093] (7) Mix 20.0g CBZS glass powder and 80.0g Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder mixture, 100g in total; add 100g of material + 300g of zirconia balls + 200mL of anhydrous ethanol into a polyethylene tetrachloroethylene tank, and ball mill in a planetary ball mill at 350r / min for 1h; after drying at 120℃, add 8% by weight of PVA solution as a binder for granulation, pass through a 20-mesh sieve, and then compress into tablets.

[0094] (8) The sample from step (7) was placed in a muffle furnace, debinded at 500°C for 2 hours, and sintered at 1200°C for 3 hours in air atmosphere to produce a ceramic sample block for a 5G dielectric filter. The microwave dielectric properties of the sample obtained in this embodiment were tested using a network analyzer and related test fixtures.

[0095] Example 6:

[0096] (1) According to the CBZS glass ratio (mol%), weigh 36.99g CaCO3, 27.16g H3BO3, 27.35g ZnO and 20.36g SiO2, pour the prepared materials into a mortar, add an appropriate amount of deionized water and stir evenly. Then place it in a platinum crucible at 1210℃ and keep it warm for 1.5h. Then pour the molten glass directly into deionized water to quench and obtain a glass sample.

[0097] (2) Place 60g of glass fragments, 180g of zirconia balls, and 120mL of anhydrous ethanol obtained in step (1) into an alumina ceramic jar and ball mill them for 3h in a planetary ball mill at a speed of 350r / min.

[0098] (3) Place the ball-milled glass powder slurry from step (2) in a 120℃ constant temperature drying oven and dry for 3 hours. After drying, pass it through an 80-mesh sieve to obtain glass powder (particle size D). 50 (≈1±0.5μm) for later use;

[0099] (4) According to Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The chemical formula for O3 is as follows: weigh out 30.61g MgO, 60.67g TiO2, 4.00g CaCO3, 1.11g ZnO, and 3.61g Nb2O5, totaling 100g; add 100g of material, 450g of zirconia balls, and 300mL of deionized water into a polyethylene tetrachloroethylene container, and ball mill in a planetary ball mill at 350r / min for 1h;

[0100] (5) Place the raw powder slurry that was ball-milled in step (4) into a constant temperature drying oven and dry it at 120°C for 3 hours. After drying, pass it through a 40-mesh sieve to obtain a uniformly mixed powder.

[0101] (6) Place the powder after sieving in step (5) into a muffle furnace and pre-calcine it at 1200℃ for 5 hours to obtain Mg. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder (particle size D)50 (≈3±0.5μm) for later use;

[0102] (7) Mix 25.0g of CBZS glass powder and 75.0g of Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder mixture, 100g in total; add 100g of material + 300g of zirconia balls + 200mL of anhydrous ethanol into a polyethylene tetrachloroethylene tank, and ball mill in a planetary ball mill at 350r / min for 1h; after drying at 120℃, add 8% by weight of PVA solution as a binder for granulation, pass through a 20-mesh sieve, and then compress into tablets.

[0103] (8) The sample from step (7) was placed in a muffle furnace, debinded at 500°C for 2 hours, and sintered at 1150°C for 3 hours in air atmosphere to produce a ceramic sample block for a 5G dielectric filter. The microwave dielectric properties of the sample obtained in this embodiment were tested using a network analyzer and related test fixtures.

[0104] Example 7:

[0105] (1) According to the CBZS glass ratio (mol%), weigh 36.99g CaCO3, 27.16g H3BO3, 27.35g ZnO and 20.36g SiO2, pour the prepared materials into a mortar, add an appropriate amount of deionized water and stir evenly. Then place it in a platinum crucible at 1210℃ and keep it warm for 1.5h. Then pour the molten glass directly into deionized water to quench and obtain a glass sample.

[0106] (2) Place 60g of glass fragments, 180g of zirconia balls, and 120mL of anhydrous ethanol obtained in step (1) into an alumina ceramic jar and ball mill them for 3h in a planetary ball mill at a speed of 350r / min.

[0107] (3) Place the ball-milled glass powder slurry from step (2) in a constant temperature drying oven at 120℃ and dry for 3 hours. After drying, pass it through an 80-mesh sieve to obtain glass powder (particle size D50≈1±0.5μm) for later use.

[0108] (4) According to Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05The chemical formula for O3 is as follows: weigh out 30.61g MgO, 60.67g TiO2, 4.00g CaCO3, 1.11g ZnO, and 3.61g Nb2O5, totaling 100g; add 100g of material, 450g of zirconia balls, and 300mL of deionized water into a polyethylene tetrachloroethylene container, and ball mill in a planetary ball mill at 350r / min for 1h;

[0109] (5) Place the raw powder slurry that was ball-milled in step (4) into a constant temperature drying oven and dry it at 120°C for 3 hours. After drying, pass it through a 40-mesh sieve to obtain a uniformly mixed powder.

[0110] (6) Place the powder after sieving in step (5) into a muffle furnace and pre-calcine it at 1200℃ for 5 hours to obtain Mg. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder (particle size D) 50 (≈3±0.5μm) for later use;

[0111] (7) Mix 30.0g CBZS glass powder and 70.0g Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder mixture, 100g in total; add 100g of material + 300g of zirconia balls + 200mL of anhydrous ethanol into a polyethylene tetrachloroethylene tank, and ball mill in a planetary ball mill at 350r / min for 1h; after drying at 120℃, add 8% by weight of PVA solution as a binder for granulation, pass through a 20-mesh sieve, and then compress into tablets.

[0112] (8) The sample from step (7) was placed in a muffle furnace, and the binder was removed at 500°C for 2 hours. The sample was then sintered at 1100°C in air for 3 hours to produce a ceramic sample block for a 5G dielectric filter.

[0113] Example 8

[0114] In this embodiment 8, the preparation process of the ceramic material for the 5G dielectric filter is the same as in embodiment 4, with the only difference being that x = 1wt%.

[0115] Example 9

[0116] In this embodiment 9, the preparation process of the ceramic material for the 5G dielectric filter is the same as in embodiment 4, with the only difference being that x = 5wt%.

[0117] Example 10

[0118] In this embodiment 10, the preparation process of the ceramic material for the 5G dielectric filter is the same as in embodiment 4, with the only difference being that x = 10wt%.

[0119] Example 11

[0120] In this embodiment 11, the preparation process of the ceramic material for the 5G dielectric filter is the same as in embodiment 4, with the only difference being that x = 25 wt%.

[0121] Example 12

[0122] In this embodiment 12, the preparation process of the ceramic material for the 5G dielectric filter is the same as in embodiment 4, with the only difference being that x = 30 wt%.

[0123] Table 1 shows the dielectric properties of the ceramic material for 5G dielectric filters prepared in the examples as a function of x (mass percentage of CBZS glass powder):

[0124]

[0125]

[0126] Table 1 shows that adjusting the ratio of CBZS glass to Mg in the composite material can help improve performance. 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3Nb 2 / 3 ) 0.05 The microwave dielectric properties of ceramic samples for 5G dielectric filters were controlled by adjusting the mass percentage of the O3 ceramic phase. The dielectric constant and temperature coefficient of resonant frequency showed a linear relationship with the glass mass percentage, as did the quality factor. This allows for precise adjustment of the composite material's dielectric properties: the dielectric constant ranged from 17.2 to 19.5. At an optimal addition ratio of 15% to 20% and a sintering temperature of 1200℃, the highest dielectric constant of 21.0, the optimal quality factor of 100,000 GHz, and the ideal temperature coefficient of resonant frequency were achieved, ranging from 0.4 to 10.5 ppm / ℃, along with the highest material density. When the addition ratio exceeded 20%, the sintering temperature decreased accordingly, and the Qf value also began to decrease, with the temperature coefficient increasing in a positive direction, which was detrimental to optimizing material performance. When the glass addition ratio was below 15% or above 20%, sintering at 1200℃ resulted in either insufficient sintering or over-sintering, leading to decreased material density and deteriorated performance.

[0127] according to Figure 1It was found that as the mass percentage of CBZS glass and ceramic phase in the ceramic sample for 5G dielectric filters changed, the main crystalline phase did not change significantly, consisting of a single magnesium titanate phase and a small amount of calcium titanate phase, without the formation of a third impurity phase, thus maintaining a high quality factor. Furthermore, as the mass of CBZS glass increased, the amount of liquid phase increased, leading to a decrease in sintering temperature. At this lower temperature, the material could be sintered densely without significant porosity, mainly because the lower Tg temperature of CBZS glass resulted in a lower sintering temperature for the composite material, which is beneficial for reducing energy consumption and controlling production costs.

Claims

1. A ceramic material for 5G dielectric filters, characterized in that, The chemical composition of the ceramic material used in the 5G dielectric filter is xCBZS glass-(1-x)Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3, wherein 15wt%≤x≤20wt%; the composition of the CBZS glass includes: 40-43 mol% CaO, 10-25 mol% B2O3, 25-30 mol% ZnO, and 10-20 mol% SiO2.

2. The ceramic material for 5G dielectric filters according to claim 1, characterized in that, The dielectric constant of the ceramic material used in the 5G dielectric filter ranges from 20.8 to 21.0, and Q×f is 85000 to 100000; the temperature coefficient of the resonant frequency of the ceramic material used in the 5G dielectric filter is 0.4 to 4.0 ppm / ℃.

3. A method for preparing a ceramic material for a 5G dielectric filter as described in claim 1 or 2, characterized in that, include: (1) Preparation of CBZS glass powder; (2) Preparation of Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder; (3) Mix CBZS glass powder and Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder according to the chemical composition of ceramic materials for 5G dielectric filters: xCBZS-(1-x)Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 is weighed and mixed, dried, and then a binder is added for granulation to obtain granulated powder; wherein, 15wt%≤x≤20wt%; (4) Press the granulated powder into a shape to obtain a green body; (5) After the blank is debonded, it is sintered at 1100-1300℃ for 3-6 hours to obtain the ceramic material for the 5G dielectric filter.

4. The preparation method according to claim 3, characterized in that, In step (1), the preparation method of the CBZS glass powder includes: first, mixing Ca source, B source, Zn source and Si source in a molar ratio of (40-43):(10-25):(25-30):(10-20) to obtain raw material mixture A; the Ca source is CaCO3 with a purity greater than 99.5%, the B source is B2O3, the Zn source is ZnO with a purity greater than 99.5%, and the Si source is SiO2 with a purity greater than 99.5%; then, melting the raw material mixture A and quenching it to obtain glass fragments; finally, grinding, drying and sieving the glass fragments to obtain the CBZS glass powder.

5. The preparation method according to claim 4, characterized in that, The melting temperature is 1100–1300℃, and the melting time is 1–2 hours.

6. The preparation method according to claim 3, characterized in that, In step (2), the Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The preparation methods of O3 ceramic powder include: first, according to Mg... 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 chemical formula: Mix Mg source, Ti source, Ca source, Zn source and Nb source to obtain raw material mixture B; then dry and sieve raw material mixture B to obtain precursor powder; finally, pre-calcine the precursor powder at 1100-1300 ℃ for 2-8 hours to obtain the Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 O3 ceramic powder.

7. The preparation method according to claim 6, characterized in that, The Mg source is MgO with a purity greater than 99.5%; the Ti source is TiO2 with a purity greater than 99.5%; the Ca source is CaO with a purity greater than 99.5%; the Zn source is ZnO with a purity greater than 99.5%; and the Nb source is Nb2O5 with a purity greater than 99.9%.

8. The preparation method according to claim 3, characterized in that, In step (3), the binder is at least one of a polyvinyl butyral solution of 8-10% by weight and a polyvinyl alcohol solution of 8-10% by weight; the binder is CBZS glass powder and Mg 0.95 Ca 0.05 Ti 0.95 (Zn 1 / 3 Nb 2 / 3 ) 0.05 The total mass of O3 ceramic powder is 10 mL: 1 g.

9. The preparation method according to claim 3, characterized in that, In step (5), the temperature of the adhesive discharge is 400-600 ℃ and the time is 1-4 hours.

Images