Preparation method of ceramic-based antenna window plate

Abstract

The invention discloses a preparation method of a ceramic-based antenna window plate, and belongs to the technical field of wave-transparent ceramics. The invention aims to solve the problem that low-cost preparation of a high-density, high-strength, high-surface-quality and high-thickness ceramic-based antenna window plate cannot be realized in the prior art. The method comprises the following steps: 1, preparing ceramic powder; 2, activating and functionalizing the surface of the powder; 3, ceramic 3D printing and degreasing; and 4, sintering and densifying the ceramic. The method is used for preparing the ceramic-based antenna window plate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wave-transparent ceramics. BACKGROUND

[0002] The antenna window is a key structure for protecting the antenna of electronic devices such as radars and communication devices on an aircraft, and needs to meet the requirements of electromagnetic wave transmission, high-temperature resistance, mechanical support, and structural stability in a temperature alternating environment, and is a core component for the normal operation of the electromagnetic system of the aircraft.

[0003] The ceramic-based antenna window has good high-temperature resistance and excellent thermal shock resistance, and does not have the problems of wave transmission rate attenuation caused by fiber scattering and structural failure caused by fiber aging, and is a commonly used technical form in the field of aerospace wave transmission. The traditional preparation methods of the ceramic-based antenna window plate mainly include the following: dry pressing forming, hot pressing sintering, spark plasma sintering, slip casting and freeze casting. Among them, dry pressing forming and hot pressing sintering can only prepare flat plate products with simple shapes; SPS sintering products are small in size and expensive in equipment; slip casting and freeze casting are difficult to control the size precision, and the density uniformity of the products is also poor. The above-mentioned manufacturing methods all belong to mold manufacturing, and the production efficiency and product characteristics are particularly dependent on the mold, which is not conducive to the rapid manufacturing of individualized, fine, lightweight and complex high-end products in some special industrial fields. However, the 3D printing technology can realize the integrated structure design and manufacturing for additive manufacturing, solve the design size change that cannot be overcome by traditional processes, greatly reduce the production flow and the number of parts of complex components, and thus greatly reduce the production cost.

[0004] The 3D printing technology of ceramics mainly includes SLS laser selective sintering technology, 3DP three-dimensional printing forming technology, FDM melting deposition technology and DLP light curing 3D printing technology. In order to meet the super-high-speed aerodynamic load and reduce stress concentration, the antenna window plate is often designed into a special-shaped structure and integrated with the aircraft, and the surface quality of the antenna window plate will also affect its wave-transparent-stealth effect, so the ceramic-based antenna window has high requirements on size precision, surface roughness, strength and high-temperature structural stability. Among the above-mentioned ceramic 3D printing technologies, the surface roughness of the samples prepared by SLS and FDM technologies is large, and the subsequent processing and polishing cost is high; the strength of the samples prepared by 3DP technology is very low, and is only suitable for some application fields with low strength requirements; and the DLP technology has great advantages, has good material compatibility, and the prepared samples have high precision, and is suitable for the preparation of special-shaped ceramic-based antenna window plates.

[0005] According to the current reports, the DLP printing wave-transparent ceramic (such as quartz ceramic) not only has low density and strength as a whole, but also has small sample size and thickness that can be prepared, which limits its application in extreme service environment to some extent. Therefore, a low-cost preparation method of ceramic-based antenna window plate with high density, high strength, high surface quality and high thickness is urgently needed. SUMMARY

[0006] The present application solves the problem that the prior art cannot realize low-cost preparation of ceramic-based antenna window plate with high density, high strength, high surface quality and high thickness, and further provides a preparation method of ceramic-based antenna window plate.

[0007] A preparation method of ceramic-based antenna window plate, which is carried out according to the following steps:

[0008] I. Preparation of ceramic powder:

[0009] Mixing the particle size graded powder with additives to obtain the ceramic powder;

[0010] II. Surface activation and functionalization of the powder:

[0011] ① Activating the ceramic powder by using radio frequency plasma to obtain activated ceramic powder;

[0012] ② Functionalizing the activated ceramic powder by using radio frequency plasma under the conditions of reaction atmosphere, gas pressure of 10 Pa to 100 Pa and power of 30 W to 300 W for 10 min to 60 min to obtain functionalized ceramic powder;

[0013] III. Ceramic 3D printing and debinding:

[0014] ① 70 parts to 90 parts of functionalized ceramic powder, 8 parts to 24 parts of photosensitive resin, 0.2 parts to 1 part of photoinitiator and 1 part to 3 parts of dispersing agent are weighed according to the mass fraction and mixed uniformly to obtain a slurry;

[0015] ② Printing is carried out by using the slurry under the conditions of printing slice thickness of 30 μm to 100 μm, exposure density of 3 mW / cm 2 ~50 mW / cm 2 and single layer exposure time of 1 s to 20 s to obtain a ceramic green body;

[0016] And the ratio of single layer solidification depth to printing slice thickness during the printing process is (1.5-4):1;

[0017] ③ The ceramic green body is washed and debound to obtain a debound ceramic green body;

[0018] IV. Ceramic sintering and densification:

[0019] ①Put the defatted ceramic green body into a flexible rubber bag, and use fluid pressure to uniformly press the green body, to obtain a ceramic green body with reduced pores;

[0020] ②Sinter the ceramic green body with reduced pores, to obtain a sintered ceramic;

[0021] ③Carry out densification treatment on the sintered ceramic in sequence, to obtain a ceramic-based antenna window panel.

[0022] The beneficial effects of the present application are:

[0023] (1) The special powder grading design and plasma functionalization synergistic treatment method can prepare a photosensitive ceramic slurry with high solid content and low viscosity, and in addition, the special particle grading will optimize the light scattering path, improve the light curing printing size accuracy and surface quality of the ceramic slurry;

[0024] (2) The special powder grading design realizes a relatively ideal particle packing hole, has good defatting property, can realize high-thickness sample preparation (i.e., the sinterable thickness is > 10 mm), the ceramic powder particle sintering dynamics is sufficient, and the volume density and bending strength of the subsequent sample are improved;

[0025] (3) The multi-stage ordered densification method further optimizes the comprehensive performance such as mechanical properties and electrical properties of the light-cured printing ceramic.

[0026] The wave-transparent ceramic sample prepared by the present application has good high-temperature stability, excellent dielectric performance, strength meeting application requirements and can realize rapid customization, solves the problem that the prior art cannot realize low-cost preparation of a ceramic-based antenna window panel with high density, high strength, high surface quality and high thickness, and has good application prospect in aircraft low-costization and clustering. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The particle size distribution curve of the particle size grading powder described in step one of Example 1;

[0028] Figure 2 The SEM picture of the ceramic powder prepared in step one of Example 1;

[0029] Figure 3 The particle size distribution curve of the particle size grading powder described in step one of Comparative Example 1;

[0030] Figure 4 The actual object picture of the ceramic green body prepared in step three ② of Example 1, a is the front view, b is the rear view, c is the side view, and d is the top view;

[0031] Figure 5Dimensional drawing of the ceramic green body prepared in Example 1 Step three 2, a is the front view, b is the back view, c is the side view, d is the top view;

[0032] Figure 6 Debinding curve drawing of the ceramic green body prepared in Example 1 Step three 3;

[0033] Figure 7 SEM drawing of the ceramic after sintering in Example 1 Step four 2;

[0034] Figure 8 XRD crystallization comparison of the ceramic after sintering in Example 1 and Comparative Example 1 Step four 2;

[0035] Figure 9 Thermal expansion coefficient comparison of the ceramic antenna window panel in Example 1 and Comparative Example 1 Step four 3. DETAILED DESCRIPTION

[0036] Detailed implementation one: the present embodiment is a kind of preparation method of ceramic antenna window panel, it is carried out according to the following steps:

[0037] I. Preparation of ceramic powder:

[0038] Mix the particle size graded powder with additives to obtain the ceramic powder;

[0039] II. Surface activation and functionalization of powder:

[0040] 1. Use radio frequency plasma to activate the ceramic powder to obtain the activated ceramic powder;

[0041] 2. Use radio frequency plasma to functionalize the activated ceramic powder under the conditions of reaction atmosphere, gas pressure 10Pa~100Pa and power 30W~300W for 10min~60min to obtain the functionalized ceramic powder;

[0042] III. Ceramic 3D printing and debinding:

[0043] 1. Take 70 parts~90 parts of the functionalized ceramic powder, 8 parts~24 parts of photosensitive resin, 0.2 parts~1 parts of photoinitiator and 1 parts~3 parts of dispersing agent by mass fraction and mix them evenly to obtain the slurry;

[0044] 2. Under the conditions of printing slice thickness 30μm~100μm, exposure density 3mW / cm 2 ~50mW / cm 2 and single layer exposure time 1s~20s, use the slurry to print to obtain the ceramic green body;

[0045] And the ratio of single layer solidification depth to printing slice thickness in the printing process is (1.5~4):1;

[0046] ③cleaning and degreasing the ceramic green body to obtain a degreased ceramic green body;

[0047] Four, ceramic sintering and densification:

[0048] ①putting the degreased ceramic green body into a flexible rubber bag, using fluid pressure to uniformly press the green body, to obtain a ceramic green body with reduced pores;

[0049] ②sintering the ceramic green body with reduced pores to obtain a sintered ceramic;

[0050] ③sequentially performing densification treatment on the sintered ceramic to obtain a ceramic-based antenna window panel.

[0051] The additive in step one of the embodiment serves as a thixotropy adjusting agent (inorganic thixotropic agent) for the slurry, or simultaneously plays a role of a sintering aid to some extent.

[0052] The traditional organic modification process uses a solution dispersion method, which has poor uniformity and a long time, and produces chemical waste liquid, and on the other hand, introduces organic matter on the surface of the powder, occupying 3vol.%~5vol.% of the raw material, directly affecting the subsequent sintering and densification of the ceramic. In addition, when some inert ceramic powders are modified with organic matter, the surface bonding is weak, and the modified matter is easy to fall off, which is not conducive to the uniform dispersion of the ceramic powder in the resin after falling off. Compared with the traditional method, the plasma treatment method in step two of the embodiment can directly introduce functional groups (active sites) on the surface of the powder particles without the help of organic modifiers, optimize the interaction between particles, reduce the aggregation and adhesion of particles, and improve the dispersibility and fluidity of the powder, which is efficient and environmentally friendly, and can further increase the proportion of ceramic components in the slurry.

[0053] Step two ① of the embodiment can effectively remove organic contaminants attached to the surface of the ceramic powder through activation treatment, and activate the surface atoms or molecules of the powder to generate new chemical active sites (such as ·N, ·OH, ·O, ·COOH). When the power is too low, the number and stability of the surface active sites are poor; while too high power may cause the surface of the powder to be etched too much, resulting in poor subsequent surface functionalization effect.

[0054] The second step of the specific embodiment is based on the first step. Without additional treatment of the powder in the rotating cavity, only by changing the atmosphere in the cavity and adjusting the relevant technical parameters, the surface functionalization of the powder can be directly carried out. The gas in the rotating cavity is excited and decomposed into active species (such as ·CF2 and ·SiH) by plasma. The active species combine with the surface atoms / molecules / free radicals of the powder to complete the surface functionalization. After surface functionalization, the contact angle of the powder is greater than 90°, and the powder has good lipophilicity and good dispersion. Without additional drying, crushing and sieving treatment, the powder can be directly used to prepare ceramic photosensitive slurry.

[0055] The beneficial effects of the embodiment are:

[0056] (1) The method of special powder grading design and plasma functionalization synergistic treatment can prepare photosensitive ceramic slurry with high solid content and low viscosity. In addition, the special particle size distribution can optimize the light scattering path and improve the light curing printing size accuracy and surface quality of the ceramic slurry.

[0057] (2) The special powder grading design realizes ideal particle packing pores, good debinding performance, and high thickness sample preparation (i.e. sintering thickness > 10 mm). The sintering dynamics of ceramic powder particles is sufficient, which improves the bulk density and bending strength of the subsequent sample.

[0058] (3) The method of multi-stage ordered densification further optimizes the comprehensive performance such as mechanical properties and electrical properties of the light-cured printed ceramic.

[0059] The wave-transparent ceramic sample prepared by the embodiment has good high-temperature stability, excellent dielectric performance, and strength that meets application requirements and can realize rapid customization. The embodiment solves the problem that the prior art cannot realize low-cost preparation of ceramic-based antenna window panels with high density, high strength, high surface quality and high thickness, and has good application prospects in aircraft cost reduction and clustering.

[0060] Specific embodiment two: The difference between the embodiment and the first specific embodiment is that: the particle size grading powder in step one is a combination of one or both of silicon oxide powder and silicon nitride powder, and the particle size grading powder is irregularly shaped powder; the additive in step one is one or a combination of several of silicon oxide, silicon nitride, boron nitride, silicon carbide, boron carbide, zirconium oxide, aluminum oxide and amorphous glass powder, and the additive is one or a combination of several of sheet-like powder, spherical-like powder, needle-like powder and columnar powder; the mass percentage of the additive in the ceramic powder in step one is 0.5% to 5%. The rest is the same as the first specific embodiment.

[0061] Specific embodiment three: the difference between this embodiment and one of the specific embodiments one or two is that: the median diameter D50 of the particle size graded powder in step one is 2 μm ~ 5 μm, the specific surface area is 2 m 2 / g ~ 10 m 2 / g, ln(D[4,3] / D[3,2]) is 0.5 ~ 1.0, wherein D[4,3] is the volume average diameter of the powder, D[3,2] is the area average diameter of the powder; the median diameter D50 of the additive in step one is different from the median diameter D50 of the particle size graded powder by 10% ~ 10%. The others are the same as specific embodiment one or two.

[0062] The greater the particle size index of this specific embodiment, the smaller the specific surface area, and the sintering kinetics is not enough; the smaller the particle size index, the greater the specific surface area of the particles in the aggregate, which is not conducive to reducing the viscosity of the slurry.

[0063] Specific embodiment four: the difference between this embodiment and one of the specific embodiments one to three is that: the activation treatment of the ceramic powder by using radio frequency plasma in step two ① is specifically performed as follows: under the conditions of a specific atmosphere, a gas pressure of 10 Pa ~ 100 Pa and a power of 30 W ~ 300 W, the activation treatment is performed for 10 min ~ 60 min; the specific atmosphere is one or a combination of several of oxygen, air, nitrogen and argon; the reaction atmosphere in step two ② is one or a combination of several of hexamethyldisiloxane, SiH4, CH4, C2H2, CF4, C3F8 and C8F 16 8. The others are the same as specific embodiments one to three.

[0064] Specific embodiment five: the difference between this embodiment and one of the specific embodiments one to four is that: the photosensitive tree in step three ① is a combination of two or several of polyurethane acrylate, polyester acrylate, epoxy acrylate, diol diacrylate, alkyl acrylate, isobornyl methacrylate, N-vinyl pyrrolidone, trimethylolpropane triacrylate and pentaerythritol tetraacrylate; the photo initiator in step three ① is a combination of one or several of (2, 4, 6-trimethylbenzoyl) bis (p-tolyl) phosphine oxide, phenyl bis (2, 4, 6-trimethylbenzoyl) phosphine oxide, 2, 4, 6-trimethylbenzoyl phenyl phosphonic acid ethyl ester and 2-hydroxy-2-methyl propiophenone; the dispersant in step three ① is a combination of one or several of hexadecyl trimethyl ammonium bromide, BYK9076, BYK110, BYK111 and castor oil. The others are the same as specific embodiments one to four.

[0065] Embodiment six: different from one of the embodiments one to five is that the volume fraction of the functionalized ceramic powder in the slurry in step three ① is 50vol%~60vol%; the debinding treatment in step three ③ is specifically performed as follows: the cleaned ceramic green body is placed in a high-temperature furnace, and heated to 150℃~600℃ at a heating rate of 0.08℃ / min~2℃ / min under air, nitrogen, argon or a mixture of nitrogen / hydrogen, and the debinding treatment is performed at a temperature of 150℃~600℃, and the total time of debinding heating and holding is 40h~60h. The others are the same as the embodiments one to five.

[0066] Embodiment seven: different from one of the embodiments one to six is that the uniform pressure of the green body by fluid pressure in step four ① is specifically performed as follows: first, pressurize to 80MPa~100MPa at a rate of 15MPa / min~30MPa / min, and hold at a pressure of 80MPa~100MPa for 2min~5min, then pressurize to 150MPa~250MPa at a rate of 15MPa / min~30MPa / min, and hold at a pressure of 150MPa~250MPa for 2min~5min, then pressurize to 280MPa~320MPa at a rate of 15MPa / min~30MPa / min, and hold at a pressure of 280MPa~320MPa for 5min~10min, and finally depressurize to 0MPa at a rate of 15MPa / min~30MPa / min. The others are the same as the embodiments one to six.

[0067] Embodiment eight: different from one of the embodiments one to seven is that the sintering in step four ② is specifically performed as follows: heat to 1000℃~1800℃ at a heating rate of 2℃ / min~5℃ / min under air, vacuum or nitrogen, and hold at a temperature of 1000℃~1800℃ for 1h~3h, and finally cool down with the furnace. The others are the same as the embodiments one to seven.

[0068] Embodiment nine: different from one of the embodiments one to eight is that the densification treatment in step four ③ is specifically one or a combination of several of the ceramic suspension filling treatment, sol impregnation treatment and precursor solution saturation treatment according to the ceramic porosity. The others are the same as the embodiments one to eight.

[0069] Specific implementation ten: the embodiment is different from one of the specific implementation one to nine: when the porosity of the sintered ceramic is > 35%, the ceramic suspension filling treatment, sol impregnation treatment and precursor solution saturation treatment are carried out in turn; when the porosity of the sintered ceramic is 15%~35%, the sol impregnation treatment and precursor solution saturation treatment are carried out in turn; when the porosity of the sintered ceramic is 10%~15%, the precursor solution saturation treatment is carried out;

[0070] The ceramic suspension filling treatment is specifically carried out by the following steps: the sintered ceramic is immersed in the ceramic suspension, then treated under the condition that the ultrasonic frequency is 20kHz~25kHz for 10min~60min, dried under the condition that the temperature is 60℃~80℃, and the immersion and drying are repeated 3~5 times to obtain the ceramic after the ceramic suspension filling treatment; the porosity of the ceramic after the ceramic suspension filling treatment is 15%~35%; the ceramic suspension is composed of nano-oxide with an average particle size of 100nm~300nm, deionized water and dispersant, the mass percentage of the nano-oxide with an average particle size of 100nm~300nm in the ceramic suspension is 20%~40%, and the nano-oxide with an average particle size of 100nm~300nm is one of silicon oxide, aluminum oxide and zirconium oxide or a combination of several thereof;

[0071] The sol infiltration treatment is specifically performed by the following steps: the ceramic after the ceramic suspension gap filling treatment is immersed in ceramic sol I, under the condition of ultrasonic frequency of 30 kHz-40 kHz, for 10 min-60 min, and then heat treated at a temperature of 80℃-250℃ for 1 h-3 h, the ceramic sol I immersion and heat treatment are repeated for 3-5 times, to obtain a preliminary densified ceramic; the preliminary densified ceramic is immersed in ceramic sol II, under the condition of ultrasonic frequency of 30 kHz-40 kHz, for 10 min-60 min, and then heat treated at a temperature of 80℃-250℃ for 1 h-3 h, the ceramic sol II immersion and heat treatment are repeated for 3-5 times, to obtain a secondary densified ceramic; the secondary densified ceramic has a porosity of 10%-15%; the ceramic sol I is composed of nano-oxide with an average particle size of 60 nm-80 nm and a water-ethanol mixture, the mass percentage of the nano-oxide with an average particle size of 60 nm-80 nm in the ceramic sol I is 30%-50%; the ceramic sol II is composed of nano-oxide with an average particle size of 10 nm-15 nm and a water-ethanol mixture, the mass percentage of the nano-oxide with an average particle size of 10 nm-15 nm in the ceramic sol II is 10%-30%; the nano-oxide with an average particle size of 60 nm-80 nm and the nano-oxide with an average particle size of 10 nm-15 nm are one of zirconium oxide, aluminum oxide, yttrium oxide and silicon oxide or a combination of several thereof;

[0072] The precursor solution saturation treatment is specifically performed by the following steps: the secondary densified ceramic is immersed in a precursor solution, under the condition of ultrasonic frequency of 30 kHz-40 kHz, for 10 min-60 min, and then cured at a temperature of 100℃-200℃ for 1 h-3 h in a nitrogen atmosphere, and then heat treated at a temperature of 900℃-1200℃ for 0.5 h-2 h in a nitrogen atmosphere to realize ceramicization, the immersion, curing and ceramicization are repeated for 3-5 times; the precursor solution is composed of a precursor molecule and a solvent, the mass percentage of the precursor molecule in the precursor solution is 1%-15%, and the precursor molecule is one of polysiloxazane, polysilazane and polyborosilazane or a combination of several thereof. The other steps are the same as steps one to nine in the embodiment.

[0073] Step four ③ in the embodiment is performed in sequence for products with different porosities, each step is repeated for 3-5 times, and when the porosity meets the condition or the porosity remains stable before and after the treatment, the next step can be performed.

[0074] The ultrasonic in step four ③ in the embodiment can accelerate liquid penetration and improve the uniformity of the internal composition distribution of the material.

[0075] The beneficial effects of the present application are verified by the following examples:

[0076] Example 1:

[0077] A preparation method of a ceramic-based antenna window panel, which is carried out according to the following steps:

[0078] I. Preparation of ceramic powder:

[0079] The particle size graded powder and the additive are mixed by using a double motion mixer for 3h under the conditions that the speed of the barrel is 25rpm and the speed of the blade is 50rpm, so as to obtain the ceramic powder;

[0080] The particle size graded powder is silica powder, and the silica powder is irregular angular powder; the additive is silica, and the additive is spherical powder; the mass percentage of the additive in the ceramic powder is 5%;

[0081] The median diameter D50 of the particle size graded powder is 2.532μm, the specific surface area is 4.36m 2 / g, and ln(D[4,3] / D[3,2]) is 0.888, wherein D[4,3] is the volume average diameter of the powder, and D[3,2] is the area average diameter of the powder; the median diameter D50 of the additive is 2.4μm;

[0082] II. Surface activation and functionalization of the powder:

[0083] ①The ceramic powder is activated by using radio frequency plasma under the conditions that the air atmosphere is 50Pa and the power is 200W for 30min, so as to obtain the activated ceramic powder;

[0084] ②The activated ceramic powder is functionalized by using radio frequency plasma under the conditions that the reaction atmosphere is 50Pa and the power is 200W for 30min, so as to obtain the functionalized ceramic powder;

[0085] The reaction atmosphere is C3F8;

[0086] III. Ceramic 3D printing and debinding:

[0087] ① Take 73 parts of functionalized ceramic powder, 23.5 parts of photosensitive resin, 0.5 parts of photoinitiator and 3 parts of dispersant by mass fraction, divide the functionalized ceramic powder into the first functionalized ceramic powder, the second functionalized ceramic powder and the third functionalized ceramic powder by mass ratio of 1:1:1; divide the dispersant into the first dispersant, the second dispersant and the third dispersant by mass ratio of 1:1:1; mix the photosensitive resin and the photoinitiator uniformly by using a vacuum stirring defoaming machine, then add the first functionalized ceramic powder and the first dispersant and mix uniformly, add the second functionalized ceramic powder and the second dispersant and mix uniformly, and finally add the third functionalized ceramic powder and the third dispersant and mix uniformly to obtain the slurry;

[0088] The photosensitive resin is a combination of polyurethane acrylate and 1,6-hexanediol diacrylate in a mass ratio of 1.5:1; the photoinitiator is 2,4,6-trimethylbenzoyl phenyl phosphonic acid ethyl ester (abbreviated as TPO-L); the dispersant is BYK111; and the volume fraction of the functionalized ceramic powder in the slurry is 52vol%;

[0089] ②Under the conditions of a printing slice thickness of 100μm, an exposure density of 4mW / cm 2 and a single-layer exposure time of 3.5s, the slurry is used for printing to obtain a ceramic body;

[0090] and the ratio of the single-layer solidification depth to the printing slice thickness in the printing process is 2.8:1;

[0091] The ceramic body is an antenna window plate, which is composed of a first arc-shaped plate and a second arc-shaped plate, the outer arc surface of the first arc-shaped plate is attached to the inner arc surface of the second arc-shaped plate, and an arc-shaped plate-shaped groove is arranged at the center of the inner arc surface of the first arc-shaped plate; the radius of the circle on which the inner arc surface of the first arc-shaped plate is located is 52.5mm, the radius of the circle on which the outer arc surface of the first arc-shaped plate and the inner arc surface of the second arc-shaped plate are located is 56mm, and the radius of the circle on which the outer arc surface of the second arc-shaped plate is located is 60.9mm; the thickness of the end surface of the first arc-shaped plate is 4.21mm, the thickness of the end surface of the second arc-shaped plate is 5.31mm, and the depth of the arc-shaped plate-shaped groove is 5.6mm; the straight-line distance between the circumferential two ends of the first arc-shaped plate is 60.2mm, the straight-line distance between the circumferential two ends of the second arc-shaped plate is 44.8mm; the axial length of the first arc-shaped plate is 56mm, and the axial length of the second arc-shaped plate is 45.5mm;

[0092] ③ washing the ceramic green body, placing the washed ceramic green body in a high-temperature furnace, heating to 300℃ at a heating rate of 1℃ / min under air, and keeping the temperature at 300℃ for 2h, heating to 360℃ at a heating rate of 0.1℃ / min, keeping the temperature at 360℃ for 5h, heating to 430℃ at a heating rate of 0.1℃ / min, keeping the temperature at 430℃ for 5h, heating to 470℃ at a heating rate of 0.1℃ / min, keeping the temperature at 470℃ for 3h, heating to 600℃ at a heating rate of 2℃ / min, keeping the temperature at 600℃ for 2h, and the total time of the debinding heating and keeping being 51h, to obtain the debinded ceramic green body;

[0093] Four, ceramic sintering and densification:

[0094] ① placing the debinded ceramic green body into a flexible rubber bag, and using fluid pressure to uniformly press the green body, to obtain a ceramic green body with reduced pores;

[0095] ② sintering the ceramic green body with reduced pores to obtain a sintered ceramic;

[0096] ③ sequentially performing ceramic suspension filling treatment, sol impregnation treatment and precursor solution saturation treatment on the sintered ceramic to obtain a ceramic-based antenna window panel.

[0097] The particle size graded powder in step one is prepared according to the following steps:

[0098] ① using a planetary wet ball mill, taking ethanol as the dispersion medium, and taking zirconium oxide as the grinding ball, under the conditions of a ball milling speed of 400rpm and a ball-to-material mass ratio of 6:1, ball milling the silicon oxide powder for 8h to obtain powder I; the mass percentage of the grinding ball with a diameter of 10mm is 50%, the mass percentage of the grinding ball with a diameter of 5mm is 30%, and the mass percentage of the grinding ball with a diameter of 3mm is 20%; the median diameter D50 of the silicon oxide powder is 20μm, and the purity is 99.9%;

[0099] ② using a planetary wet ball mill, taking ethanol as the dispersion medium, and taking zirconium oxide as the grinding ball, under the conditions of a ball milling speed of 400rpm and a ball-to-material mass ratio of 3:1, ball milling the silicon oxide powder for 5h to obtain powder II; the mass percentage of the grinding ball with a diameter of 10mm is 20%, the mass percentage of the grinding ball with a diameter of 5mm is 50%, and the mass percentage of the grinding ball with a diameter of 3mm is 30%; the median diameter D50 of the silicon oxide powder is 20μm, and the purity is 99.9%;

[0100] ③ Powder III is obtained by wet planetary ball milling with ethanol as the dispersion medium and zirconium oxide as the grinding ball under the conditions of a ball milling speed of 300 rpm and a ball-to-material mass ratio of 3:1 for 10 h; the mass percentage of the grinding ball with a diameter of 5 mm in the grinding ball is 50%, and the mass percentage of the grinding ball with a diameter of 3 mm in the grinding ball is 50%; the median diameter D50 of the silica powder is 20 μm, and the purity is 99.9%;

[0101] ④ The particle size graded powder is obtained by mixing 2 parts of powder I, 4 parts of powder II and 4 parts of powder III by mass fraction with a double-motion mixer under the conditions of a barrel speed of 25 rpm and a blade speed of 50 rpm for 3 h.

[0102] The uniform pressure of the green body by fluid pressure in step four ① is specifically performed by the following steps: first, the pressure is increased to 100 MPa at a rate of 20 MPa / min, and the pressure is kept at 100 MPa for 2 min; then, the pressure is increased to 200 MPa at a rate of 20 MPa / min, and the pressure is kept at 200 MPa for 3 min; then, the pressure is increased to 300 MPa at a rate of 20 MPa / min, and the pressure is kept at 300 MPa for 5 min; finally, the pressure is released to 0 MPa at a rate of 30 MPa / min.

[0103] The sintering in step four ② is specifically performed by the following steps: the temperature is increased to 1250 ℃ at a rate of 5 ℃ / min under nitrogen, and the temperature is kept at 1250 ℃ for 2 h, and finally the furnace is cooled down; the porosity of the sintered ceramic in step four ② is 42%.

[0104] The ceramic suspension gap filling treatment in step four ③ is specifically performed by the following steps: the sintered ceramic is immersed in the ceramic suspension, and then treated under the condition of an ultrasonic frequency of 20 kHz for 30 min, and then dried at a temperature of 80 ℃, and the immersion and drying are repeated for 3 times to obtain the ceramic suspension gap filling treated ceramic; the porosity of the ceramic suspension gap filling treated ceramic is 30%; the ceramic suspension is composed of nano-oxide with an average particle size of 200 nm, deionized water and a dispersant (crystal fire glass, LJN-30), the mass percentage of the nano-oxide with an average particle size of 200 nm in the ceramic suspension is 20%, and the nano-oxide with an average particle size of 200 nm is silicon oxide;

[0105] The sol infiltration treatment in step four ③ is carried out by the following steps: the ceramic after the joint treatment of the ceramic suspension is dipped in the ceramic sol I, and is treated under the condition of ultrasonic frequency of 30 kHz for 30 min, and then is heat treated at a temperature of 200 ℃ for 2 h, and the dipping and heat treatment of the ceramic sol I are repeated for 3 times to obtain the primary densified ceramic; the primary densified ceramic is dipped in the ceramic sol II, and is treated under the condition of ultrasonic frequency of 30 kHz for 30 min, and then is heat treated at a temperature of 200 ℃ for 2 h, and the dipping and heat treatment of the ceramic sol II are repeated for 3 times to obtain the secondary densified ceramic; the porosity of the secondary densified ceramic is 14%; the ceramic sol I is composed of nano-oxide with an average particle size of 80 nm and water-ethanol mixed solution (crystal fire glass, model ZJN-80), and the mass percentage of the nano-oxide with an average particle size of 80 nm in the ceramic sol I is 30%; the ceramic sol II is composed of nano-oxide with an average particle size of 15 nm and water-ethanol mixed solution (crystal fire glass, model JA-10), and the mass percentage of the nano-oxide with an average particle size of 15 nm in the ceramic sol II is 10%; the nano-oxide with a particle size of 80 nm and the nano-oxide with an average particle size of 15 nm are both silicon oxide;

[0106] The precursor solution saturation treatment in step four ③ is carried out by the following steps: the secondary densified ceramic is dipped in the precursor solution, and is treated under the condition of ultrasonic frequency of 30 kHz for 30 min, and then is solidified at a temperature of 150 ℃ for 2 h in a nitrogen atmosphere, and then is heat treated at a temperature of 900 ℃ for 1 h in a nitrogen atmosphere to realize the ceramization, and the dipping, solidification and ceramization are repeated for 3 times; the precursor solution is composed of a precursor molecule and a solvent (Qingci Science and Technology, TC-P05), and the mass percentage of the precursor molecule in the precursor solution is 2%, and the precursor molecule is methyl polysilazane.

[0107] Example 2: The difference between this example and example 1 is that: the additive in step one is boron nitride, and the additive is a sheet-like powder; the mass percentage of the additive in the ceramic powder in step one is 2%; the median diameter D50 of the additive is 2.7 μm; step two ① utilizes radio frequency plasma to activate the ceramic powder under the condition of nitrogen atmosphere, gas pressure of 20 Pa and power of 250 W for 40 min to obtain the activated ceramic powder; the reaction atmosphere in step two ② is C8F 16; the sintering in step four ② is performed by heating to 1150℃ at a heating rate of 5℃ / min under nitrogen, and keeping the temperature at 1150℃ for 2h, and finally cooling down with the furnace; the porosity of the sintered ceramic in step four ② is 20%; the ceramic suspension filling treatment in step four ③ is omitted; in the sol infiltration treatment in step four ③: the ceramic sol I is composed of nano-oxide with an average particle size of 60nm and water-ethanol mixture, the mass percentage of nano-oxide with an average particle size of 60nm in the ceramic sol I is 40%; the ceramic sol II is composed of nano-oxide with an average particle size of 10nm and water-ethanol mixture, the mass percentage of nano-oxide with an average particle size of 10nm in the ceramic sol II is 20%; the nano-oxide with an average particle size of 60nm and the nano-oxide with an average particle size of 10nm are both silicon oxide; the porosity of the ceramic after secondary densification is 10%; in the precursor solution saturation treatment in step four ③: the ceramicization is realized by heat treatment under nitrogen atmosphere and at a temperature of 1000℃ for 0.5h; the mass percentage of the precursor molecules in the precursor solution is 4%, and the precursor molecules are polysilazane. The other steps are the same as in example 1.

[0108] Comparative example 1: this comparative experiment is different from example 1 in that: the median diameter D50 of the particle size graded powder in step one is 2.401μm, the specific surface area is 5.05m 2 / g, and ln(D[4,3] / D[3,2]) is 0.387, wherein D[4,3] is the volume average diameter of the powder, and D[3,2] is the area average diameter of the powder; the particle size graded powder in step one is prepared by the following steps:

[0109] ①using a planetary wet ball mill, with ethanol as the dispersion medium, and with zirconium oxide as the grinding ball, under the conditions of a ball milling speed of 400rpm and a ball-to-material mass ratio of 6:1, silica powder is ball milled for 3h to obtain powder I; the mass percentage of grinding balls with a diameter of 10mm in the grinding balls is 50%, the mass percentage of grinding balls with a diameter of 5mm is 30%, and the mass percentage of grinding balls with a diameter of 3mm is 20%; the median diameter D50 of the silica powder is 20μm, and the purity is 99.9%;

[0110] ②adopting planetary wet ball milling, taking ethanol as the dispersion medium, taking zirconium oxide as the grinding ball, under the conditions of ball milling rotation speed of 400 rpm and ball material mass ratio of 3:1, the silica powder is ball milled for 3 h to obtain powder II; the mass percentage of the grinding ball with a diameter of 10 mm is 20%, the mass percentage of the grinding ball with a diameter of 5 mm is 50%, and the mass percentage of the grinding ball with a diameter of 3 mm is 30%; the median diameter D50 of the silica powder is 20 μm, and the purity is 99.9%;

[0111] ③adopting planetary wet ball milling, taking ethanol as the dispersion medium, taking zirconium oxide as the grinding ball, under the conditions of ball milling rotation speed of 300 rpm and ball material mass ratio of 3:1, the silica powder is ball milled for 3 h to obtain powder III; the mass percentage of the grinding ball with a diameter of 5 mm is 50%, and the mass percentage of the grinding ball with a diameter of 3 mm is 50%; the median diameter D50 of the silica powder is 20 μm, and the purity is 99.9%;

[0112] ④adopting planetary wet ball milling, taking ethanol as the dispersion medium, taking zirconium oxide as the grinding ball, under the conditions of ball milling rotation speed of 200 rpm and ball material mass ratio of 3:1, the silica powder is ball milled for 3 h to obtain powder IV; the mass percentage of the grinding ball with a diameter of 5 mm is 50%, and the mass percentage of the grinding ball with a diameter of 3 mm is 50%; the median diameter D50 of the silica powder is 20 μm, and the purity is 99.9%;

[0113] ⑤according to the mass fraction, 2 parts of powder I, 2 parts of powder II, 4 parts of powder III and 2 parts of powder IV are taken, and the double motion mixer is used, under the conditions of the barrel rotation speed of 25 rpm and the blade rotation speed of 50 rpm, the powder I, the powder II, the powder III and the powder IV are mixed for 3 h to obtain the particle size grading powder; the ratio of the single layer solidification depth to the printing slice thickness in the printing process in step three ② is 3:1. The other steps are the same as those in example 1.

[0114] Comparative example 2: different from example 1 is that: in step two, the traditional method of coating the powder surface with organic matter is used for modification. The specific steps are: according to the mass fraction, 96 parts of ceramic powder, 4 parts of stearic acid and 100 parts of alcohol are taken, zirconium oxide is used as the grinding ball, under the conditions of ball milling rotation speed of 200 rpm and ball material mass ratio of 3:1, ball milling for 5 h, and after ball milling, the powder is dried, broken and treated by passing through a 100 mesh screen to obtain the functionalized ceramic powder; the mass percentage of the grinding ball with a diameter of 10 mm is 20%, the mass percentage of the grinding ball with a diameter of 5 mm is 50%, and the mass percentage of the grinding ball with a diameter of 3 mm is 30%. The other steps are the same as those in example 1.

[0115] Comparative example 3: different from example 1 is that: step four ③ is cancelled. The other steps are the same as those in example 1.

[0116] The main function of the additive in Step One of Example 1 and Comparative Example 1 is to adjust the thixotropy of the slurry. The main function of the additive in Step One of Example 2 is to adjust the thixotropy of the slurry and reduce the sintering temperature of the ceramic.

[0117] The contact angle of the functionalized ceramic powder in Step Two ② of Example 1 and Comparative Example 1 is 120°, and the contact angle of the functionalized ceramic powder in Step Two ② of Example 2 is 100°; both have good lipophilicity and can be directly used to prepare a ceramic photosensitive slurry.

[0118] Figure 1 The particle size distribution curve of the particle size graded powder described in Step One of Example 1 is shown in the figure. As can be seen from the figure, the particle size distribution of the powder is wide and shows a unimodal distribution. The sub-micron fine particles in the powder provide sufficient sintering kinetics during the sintering process of the ceramic, the coarse particles not only serve as a ceramic skeleton, but also can reduce the specific surface area of the powder and increase the solid content, the medium particles are the peak particles, and the sintering kinetics and specific surface area are moderate, and together with the sub-micron fine particles and coarse particles, they can achieve close packing.

[0119] Figure 2 The SEM picture of the ceramic powder prepared in Step One of Example 1 is shown in the figure. As can be seen from the figure, the particle size of the powder is relatively uniform, and the spherical particle powder is filled in a large number of irregularly shaped particle powders. Due to the "rolling ball effect" of the spherical particles, the rheological properties of the subsequent slurry during the printing process can be adjusted to a certain extent.

[0120] Figure 3 The particle size distribution curve of the particle size graded powder described in Step One of Comparative Example 1 is shown in the figure. As can be seen from the figure, the particle size distribution is relatively narrow, and the percentage content of the peak particle size is too high, which does not meet the special grading design range of the present application and is also not conducive to the preparation of the subsequent slurry and the sintering of the ceramic.

[0121] Example 1 and Comparative Example 1 use a process with an exposure density of 4 mW / cm 2 and a single-layer exposure time of 3.5 s for photocuring printing. The grading design of Example 1 is reasonable, the small particles mainly scatter the ultraviolet light, and the large particles mainly transmit the ultraviolet light, so the size accuracy of the printed sample is closer to the designed size (the size error is controlled within 0.2%~0.5%). However, the particle size of Comparative Example 1 is too concentrated, which cannot fully play the scattering / transmission effect of different particle sizes on the ultraviolet light, so the printed size of the sample deviates more from the designed size (the size error is 0.8%~2%), that is, the printing accuracy of Example 1 with special grading design is higher.

[0122] Table 1 Comparison of powder, slurry performance and printing accuracy in Example 1 and Comparative Example 1

[0123]

[0124] From the table, the various parameters of Example 1 and Comparative Example 1 are compared: the median diameter and specific surface area of the two powders are similar, but there is a difference in the particle size index ln(D[4,3] / D[3,2]). Ceramic slurry is prepared using the two powders, and under the same solid content (52vol%) conditions, the slurry of Example 1 has lower viscosity. Using the two slurries for 3D printing (slice thickness 100μm), the surface roughness of the sample of Example 1 is smaller, and the printing precision error range is smaller, i.e. the printing precision is higher.

[0125] Figure 4 The figure is a physical diagram of the ceramic green body prepared in step three ② of Example 1, a is the front view, b is the back view, c is the side view, and d is the top view; as can be seen from the figure, the actual size of the sample is basically the same as the model size, the edge is clear, the surface roughness is low, and the precision is high.

[0126] Figure 5 The figure is a size diagram of the ceramic green body prepared in step three ② of Example 1, a is the front view, b is the back view, c is the side view, and d is the top view;

[0127] Figure 6 The figure is a debinding curve of Example 1 step three ③; as can be seen from the figure, the debinding interval of the sample is mainly concentrated in 300℃~470℃, and the time consumption is about 51h.

[0128] Figure 7 The figure is a SEM of the ceramic after sintering in step four ② of Example 1; as can be seen from the figure, the particles of each powder are tightly combined, and the sintering density is high.

[0129] Figure 8 The figure is an XRD crystallization comparison of the ceramic after sintering in step four ② of Example 1 and Comparative Example 1; Figure 9 The figure is a comparison of the thermal expansion coefficient of the ceramic antenna window panel in step four ③ of Example 1 and Comparative Example 1; from Figure 8 and Figure 9 It can be seen from the comparison that the ordinary graded powder has a large amount of cristobalite phase introduced due to unreasonable design under the same sintering process, and the cristobalite is prone to phase transition and volume expansion. The thermal expansion coefficient of Example 1 is 0.5×10 -6 K -1 The thermal expansion coefficient of Comparative Example 1 is 0.8×10 -6 K -1 At the same time, it also weakens the thermal shock resistance of the material, and the structure size stability is poor, which is not conducive to its comprehensive application in high temperature service environment.

[0130] For ceramic samples, the thicker the sample, the more difficult it is to sinter. In order to compare the difference between the powder of the embodiment and the powder of the comparative example, the sinterable thickness t of the two slurries was tested. The specific method is as follows: 90mm×50mm×tmm (length×width×thickness) samples were prepared using the process methods of the embodiment and the comparative example respectively. When the sample thickness exceeds a certain t value, the ceramic after sintering in step 4② will produce defects such as cracks, pores, clamping and warping deformation, while when it is lower than the t value, the ceramic after sintering in step 4② will not have the above defects. At this time, the t value is the achievable sinterable thickness. After experiments, the sinterable thickness of Example 1 is 11.3mm, and the sinterable thickness of Comparative Example 1 is 8.7mm. Example 1 is better than Comparative Example 1.

[0131] Table 2 Comparison of performance of ceramic-based antenna window plate in step 4 of the embodiment and comparative example

[0132]

[0133] The properties of the ceramic sample prepared in Example 1 are as follows: 2. As can be seen from the table, Example 1 is a relatively optimal preparation method, and the overall performance of the prepared sample is relatively excellent. The flexural strength and thermal shock resistance also meet practical application requirements (generally required to be greater than 50 MPa, >700°C), the dielectric constant and dielectric loss are low, and the wave transmission performance is good.

[0134] In Comparative Example 1, due to an unreasonable powder gradation, the slurry solids content could not be effectively increased, the green body degreasing process was also difficult, and the achievable sintering thickness was relatively small (Table 2). The ceramic skeleton is the primary factor affecting the mechanical properties of ceramics. Even though Comparative Example 1 introduced a suspension and impregnation solution during the subsequent densification process to achieve densification, its flexural strength was relatively low, the dielectric loss was relatively high, and the thermal shock resistance was also inferior to that of Example 1.

[0135] A small amount of inorganic additives in Example 2 can significantly improve the bending strength of the ceramic sample and reduce the open porosity, but the prepared sample has poor thermal shock resistance and is suitable for working conditions with low thermal shock requirements.

[0136] Comparative Example 2 uses a traditional coating modification method to treat the powder to improve its lipophilicity, but the introduced organic matter affects the pore size and initial porosity during subsequent ceramic sintering. As shown in Table 2, Example 1 and Comparative Example 2 have similar other properties, but the mechanical properties of Comparative Example 2 are lower than those of Example 1.

[0137] The ceramic sample in Example 3 that has not been densified has low bending strength and cannot meet the needs of actual application.

Claims

1. A method for preparing a ceramic-based antenna window plate, characterized in that It is carried out in the following steps:

1. Preparation of ceramic powder: mixing the particle size-graded powder with additives to obtain ceramic powder; 2. Powder surface activation and functionalization: ① Using radio frequency plasma to activate ceramic powder to obtain activated ceramic powder; ② Using radio frequency plasma, under the conditions of reaction atmosphere, gas pressure of 10Pa~100Pa and power of 30W~300W, the activated ceramic powder is functionalized for 10min~60min to obtain functionalized ceramic powder; 3. Ceramic 3D printing and degreasing: ① Weigh 70-90 parts by mass of functionalized ceramic powder, 8-24 parts of photosensitive resin, 0.2-1 part of photoinitiator, and 1-3 parts of dispersant and mix them evenly to obtain a slurry; ② When the thickness of the printed slice is 30μm~100μm and the exposure density is 3mW / cm 2 ~50mW / cm 2 and a single-layer exposure time of 1s to 20s, printing is performed using the slurry to obtain a ceramic body; And the ratio of single layer curing depth to printed slice thickness during printing is (1.5~4):1; ③ Cleaning and degreasing the ceramic body to obtain a degreased ceramic body; 4. Ceramic sintering and densification: ①Put the degreased ceramic body into a flexible rubber bag and use fluid pressure to uniformly pressurize the body to obtain a ceramic body with reduced pores; ② Sintering the ceramic body after reducing pores to obtain sintered ceramics; ③ The sintered ceramics are subjected to densification treatment in sequence to obtain a ceramic-based antenna window plate.

2. The method for preparing a ceramic-based antenna window plate according to claim 1, characterized in that The particle size distribution powder described in step one is a combination of one or two of silicon oxide powder and silicon nitride powder, and the particle size distribution powder is an irregularly shaped powder; the additive described in step one is one or a combination of several of silicon oxide, silicon nitride, boron nitride, silicon carbide, boron carbide, zirconium oxide, aluminum oxide and amorphous glass powder, and the additive is one or a combination of several of lamellar powder, spherical powder, needle-shaped powder and columnar powder; the mass percentage of the additive in the ceramic powder described in step one is 0.5%~5%.

3. The method for preparing a ceramic-based antenna window plate according to claim 1, characterized in that The median diameter D50 of the particle size distribution powder described in step 1 is 2μm~5μm, and the specific surface area is 2m 2 / g~10m 2 / g, ln(D[4,3] / D[3,2]) is 0.5~1.0, where D[4,3] is the volume average diameter of the powder, and D[3,2] is the area average diameter of the powder; the median diameter D50 of the additive described in step 1 differs from the median diameter D50 of the particle size graded powder by -10%~10%.

4. The method for preparing a ceramic-based antenna window plate according to claim 1, characterized in that The activation treatment of the ceramic powder by radio frequency plasma described in step 2 (1) is specifically carried out according to the following steps: activation treatment for 10 min to 60 min under a specific atmosphere, a pressure of 10 Pa to 100 Pa and a power of 30 W to 300 W; the specific atmosphere is one or a combination of oxygen, air, nitrogen and argon; the reaction atmosphere described in step 2 (2) is hexamethyldisiloxane, SiH4, CH4, C2H2, CF4, C3F8 and C8F 16 One or a combination of several of them.

5. The method for preparing a ceramic-based antenna window plate according to claim 1, characterized in that The photosensitive resin described in step 3① is two or more of polyurethane acrylate, polyester acrylate, epoxy acrylate, glycol diacrylate, alkyl acrylate, isobornyl methacrylate, N-vinyl pyrrolidone, trimethylolpropane triacrylate and pentaerythritol tetraacrylate; the photoinitiator described in step 3① is one or more of (2,4,6-trimethylbenzoyl) di(p-tolyl) phosphine oxide, phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate and 2-hydroxy-2-methylpropiophenone; the dispersant described in step 3① is one or more of cetyltrimethylammonium bromide, BYK9076, BYK110, BYK111 and castor oil.

6. The method for preparing a ceramic-based antenna window plate according to claim 1, characterized in that The volume fraction of the functionalized ceramic powder in the slurry described in step 3① is 50vol%~60vol%; the degreasing treatment described in step 3③ is specifically carried out according to the following steps: the cleaned ceramic body is placed in a high-temperature furnace, and in the presence of air, nitrogen, argon or a mixture of nitrogen / hydrogen, the temperature is increased at a heating rate of 0.08℃ / min~2℃ / min to 150℃~600℃, and degreasing is performed at a temperature of 150℃~600℃, and the total degreasing heating and holding time is 40h~60h.

7. The method for preparing a ceramic-based antenna window plate according to claim 1, characterized in that The use of fluid pressure to uniformly pressurize the green body as described in step 4① is specifically carried out according to the following steps: first, increase the pressure to 80MPa~100MPa at a rate of 15MPa / min~30MPa / min, and maintain the pressure for 2min~5min under the pressure of 80MPa~100MPa, then increase the pressure to 150MPa~250MPa at a rate of 15MPa / min~30MPa / min, and maintain the pressure for 2min~5min under the pressure of 150MPa~250MPa, then increase the pressure to 280MPa~320MPa at a rate of 15MPa / min~30MPa / min, and maintain the pressure for 5min~10min under the pressure of 280MPa~320MPa, and finally release the pressure to 0MPa at a rate of 15MPa / min~30MPa / min.

8. The method for preparing a ceramic-based antenna window plate according to claim 1, wherein The sintering described in step 4② is specifically carried out according to the following steps: heating to 1000℃~1800℃ at a heating rate of 2℃ / min~5℃ / min in air, vacuum or nitrogen, and keeping the temperature at 1000℃~1800℃ for 1h~3h, and finally cooling with the furnace.

9. The method for preparing a ceramic-based antenna window plate according to claim 1, characterized in that The densification treatment described in step 4③ is specifically to select one or a combination of ceramic suspension filling treatment, sol infiltration treatment and precursor solution saturation treatment based on the ceramic porosity.

10. The method for preparing a ceramic-based antenna window plate according to claim 9, characterized in that When the porosity of the sintered ceramic is greater than 35%, ceramic suspension filling treatment, sol infiltration treatment and precursor solution saturation treatment are carried out in sequence; when the porosity of the sintered ceramic is between 15% and 35%, sol infiltration treatment and precursor solution saturation treatment are carried out in sequence; when the porosity of the sintered ceramic is between 10% and 15%, precursor solution saturation treatment is carried out; The ceramic suspension caulking treatment is specifically carried out according to the following steps: immersing the sintered ceramic in a ceramic suspension, then treating it at an ultrasonic frequency of 20kHz to 25kHz for 10min to 60min, and then drying it at a temperature of 60°C to 80°C, repeating the immersion and drying 3 to 5 times to obtain a ceramic treated with the ceramic suspension caulking treatment; the porosity of the ceramic treated with the ceramic suspension caulking treatment is 15% to 35%; the ceramic suspension is composed of nano-oxides with an average particle size of 100nm to 300nm, deionized water and a dispersant, the mass percentage of the nano-oxides with an average particle size of 100nm to 300nm in the ceramic suspension is 20% to 40%, and the nano-oxides with an average particle size of 100nm to 300nm are one or a combination of several of silicon oxide, aluminum oxide and zirconium oxide; The sol infiltration treatment is specifically carried out according to the following steps: the ceramic after the ceramic suspension filling treatment is immersed in ceramic sol I, and the treatment is carried out for 10min~60min under the condition of an ultrasonic frequency of 30kHz~40kHz, and then the heat treatment is carried out for 1h~3h at a temperature of 80℃~250℃, and the ceramic sol I impregnation and heat treatment are repeated 3~5 times to obtain a preliminary densified ceramic; the preliminary densified ceramic is immersed in ceramic sol II, and the treatment is carried out for 10min~60min under the condition of an ultrasonic frequency of 30kHz~40kHz, and then the heat treatment is carried out for 1h~3h at a temperature of 80℃~250℃, and the ceramic sol II impregnation and heat treatment are repeated 3~5 times to obtain a secondary densified ceramic; the secondary densified ceramic The porosity of the porcelain is 10% to 15%; the ceramic sol I is composed of nano-oxides with an average particle size of 60 nm to 80 nm and a water-ethanol mixture, and the mass percentage of the nano-oxides with an average particle size of 60 nm to 80 nm in the ceramic sol I is 30% to 50%; the ceramic sol II is composed of nano-oxides with an average particle size of 10 nm to 15 nm and a water-ethanol mixture, and the mass percentage of the nano-oxides with an average particle size of 10 nm to 15 nm in the ceramic sol II is 10% to 30%; the nano-oxides with an average particle size of 60 nm to 80 nm and the nano-oxides with an average particle size of 10 nm to 15 nm are each one of zirconium oxide, aluminum oxide, yttrium oxide and silicon oxide, or a combination of several thereof; The saturated treatment of the precursor solution is specifically carried out according to the following steps: immersing the secondary densified ceramic in the precursor solution, treating it for 10 minutes to 60 minutes under an ultrasonic frequency of 30kHz to 40kHz, then curing it for 1 hour to 3 hours under a nitrogen atmosphere and a temperature of 100°C to 200°C, and after curing, heat treating it for 0.5 hours to 2 hours under a nitrogen atmosphere and a temperature of 900°C to 1200°C to achieve ceramicization, and repeating the immersion, curing and ceramicization 3 to 5 times; the precursor solution is composed of precursor molecules and a solvent, the mass percentage of the precursor molecules in the precursor solution is 1% to 15%, and the precursor molecules are one or a combination of several of polysiloxazane, polysilazane and polyborosilazane.

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