Intermediate microwave dielectric ceramic material and preparation method thereof

Abstract

The invention relates to the technical field of ceramic materials, and discloses a medium microwave dielectric ceramic material and a preparation method thereof, the medium microwave dielectric ceramic material comprises a main phase ceramic and a sintering aid accounting for pwt% of the main phase ceramic; the main phase ceramic is prepared from the following components in percentage by mass: mwt% of (Ca < 1-x > Sr < x >) < 1-y > Sm < 2y / 3 > TiO3 and nwt% of Y < 1-z > Sm < z > AlO3; the sintering aid is prepared from the following components in percentage by weight: awt% of SiO2, bwt% of Al2O3, cwt% of SrCO3, dwt% of ZrO2, ewt% of TiO2-fwt% of B2O3; wherein 0 lt; p < = 0.6; 46.5 < = m < = 73.0, 27.0 < = n < = 53.5, and m + n = 100. According to the invention, the main phase ceramic and the sintering aid are cooperatively regulated and controlled, so that the obtained material can be sintered compactly in a relatively low medium temperature range, has a moderate dielectric constant and a near-zero temperature coefficient, and has a relatively high practical value.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic materials, and in particular to an intermediate microwave dielectric ceramic material and a preparation method thereof. Background Art

[0002] 5G communication technology accesses microwave devices, and its upstream materials need to have the characteristics of miniaturization, high frequency and high Q value. In view of the above requirements, microwave dielectric ceramic materials have "innate advantages". Microwave dielectric ceramic materials have excellent properties such as low loss, small frequency temperature coefficient, wide temperature application range, no signal shielding, and high hardness. They can meet the development trend and higher requirements of microwave devices and are key materials for modern microwave communications such as mobile communications, Bluetooth technology and wireless local area networks.

[0003] Dielectric filters are microwave devices with large usage, among which 5G base station filters are mainly divided into metal cavity filters and ceramic dielectric filters. Compared with traditional metal cavity filters, the inherent material property advantages of microwave dielectric ceramics make ceramic dielectric filters smaller in size and insertion loss, which meets the development trend and high requirements of miniaturization and high Q value of microwave devices under the 5G technology framework.

[0004] In order to adapt to microwave devices for 5G communications, the development and modification of microwave dielectric ceramic material systems have received increasing attention. In order to meet the needs of devices in different communication frequency bands, the dielectric constants of microwave dielectric ceramic materials are required to be serialized. There are many systems of microwave dielectric ceramic materials with medium dielectric constants, but they all have certain shortcomings, such as in (Zr, Sn)TiO 4 The ceramic system uses the more expensive SnO 2 As a raw material, its production cost is relatively high. In addition, the thermal expansion coefficient of the ceramic is only 6-7ppm / ℃. After the product made of this material is welded with the PCB board, the thermal expansion coefficients of the two are seriously mismatched, and there is a risk of cracking when used in an environment with a large temperature difference. The invention patent with publication number CN114315343B discloses a microwave dielectric material with a dielectric constant of high Q value and its preparation method, including CaTiO 3 -YAlO 3 The sintering temperature of the series of materials is above 1550℃, the processing energy consumption is high, the sintering equipment requirements are high, and it is difficult to simultaneously meet the comprehensive requirements of high quality factor, near-zero resonant frequency temperature coefficient and low cost. In the medium and high temperature material system sintered at 1200-1400℃, BaTi 4 O 9 and Ba 2 Ti 9 O 20Intermediate materials such as these have similar dielectric properties, but such materials usually have a thermal expansion coefficient of 8 ppm / °C and a flexural strength of about 80 - 100 MPa. When the products prepared from them are subjected to thermal shock or external force shock, there is also a relatively high risk of cracking. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides an intermediate microwave dielectric ceramic material and a preparation method thereof. By regulating the formula and element selection of the main phase ceramic and cooperating with a sintering aid, the obtained material can have a relatively low sintering temperature, good stability, and moderate dielectric constant (ε r = 36 - 42), near-zero frequency temperature coefficient, high strength, and thermal expansion coefficient in the same system. Moreover, the preparation method has simple process, good repeatability, low energy consumption, and is suitable for batch industrial production and application.

[0006] The object of the present invention is achieved by the following technical solutions: In a first aspect, the present invention provides an intermediate microwave dielectric ceramic material, which includes a main phase ceramic and a sintering aid accounting for pwt% of the main phase ceramic; the main phase ceramic is composed of mwt% of (Ca 1-x Sr x ) 1-y Sm 2y / 3 TiO 3 and nwt% of Y 1-z Sm z AlO 3 ; the composition of the sintering aid is awt% SiO 2 -bwt% Al 2 O 3 -cwt% SrCO 3 -dwt% ZrO 2 -ewt% TiO 2 -fwt% B 2 O 3 ; wherein, 0 < p ≤ 0.6; 46.5 ≤ m ≤ 73.0, 27.0 ≤ n ≤ 53.5, m + n = 100; 0 ≤ x ≤ 0.2, 0 ≤ y ≤ 0.26, 0 ≤ z ≤ 0.2; 30 ≤ a ≤ 45, 20 ≤ b ≤ 35, 20 ≤ c ≤ 30, 0 ≤ d ≤ 5, 0 ≤ e ≤ 5, 0 ≤ f ≤ 15, and a + b + c + d + e + f = 100.

[0007] Preferably, the sintering aid is prepared by melting and quenching the raw materials at 1450 - 1550 °C; the raw materials include SiO 2 , Al 2 O 3 , SrCO 3 , TiO 2, ZrO 2 and H 3 BO 3 Three or more of the above.

[0008] In a second aspect, the present invention provides a method for preparing an intermediate microwave dielectric ceramic material, comprising the following steps: (1) Press (Ca 1-x Sr x ) 1-y Sm 2y / 3 TiO 3 Weigh the raw material CaCO in the stoichiometric ratio 3 、SrCO 3 、Sm 2 O 3 and TiO 2 , then add water to wet mix, then dry, the resulting mixture is sieved and calcined to obtain the main phase ceramic I; (2) Press Y 1-z Sm z AlO 3 Weigh the raw material Sm in the stoichiometric ratio 2 O 3 , Y 2 O 3 and Al 2 O 3 , then add water to wet mix, then dry, the resulting mixture is sieved and calcined to obtain the main phase ceramic II; (3) According to awt%SiO 2 -bwt%Al 2 O 3 -cwt% SrCO 3 -dwt% ZrO 2 -ewt%TiO 2 -fwt%B 2 O 3 Weigh the raw material SiO in the stoichiometric ratio 2 、Al 2 O 3 、SrCO 3 、TiO 2 、ZrO 2 and H 3 BO 3 , adding anhydrous ethanol to wet mix, and then drying, the obtained mixture is sieved and melted, and then the melt is quenched to obtain a sintering aid; (4) mixing the main phase ceramic I, the main phase ceramic II and the sintering aid, adding water for wet mixing, and then drying; (5) A binder is then added and mixed, and the mixture is pressed and sintered in sequence to obtain an intermediate microwave dielectric ceramic material.

[0009] Preferably, in step (1), the material-water mass ratio in the wet mixing process is 1:1.5-2.5, and the mixing time is 16-24 hours; and the calcination is performed at 1150-1200° C. for 2-4 hours.

[0010] Preferably, in step (2), the material-water mass ratio in the wet mixing process is 1:1.5-2.0, and the mixing time is 16-24 hours; and the calcination is performed at 1200-1250° C. for 2-4 hours.

[0011] Preferably, in step (3), the material-water mass ratio in the wet mixing process is 1:1.0-2.0, the mixing time is 18-24 hours; and the mesh size of the sieving sieve is 200-300 meshes.

[0012] Preferably, in step (3), the melting is firstly heated to 1000°C at 5-8°C / min, and then heated to 1450-1550°C at 1-3°C / min for melting for 1-2h.

[0013] Preferably, in step (4), the material-water mass ratio in the wet mixing process is 1:1.0-1.5, and the mixing time is 12-18 hours.

[0014] Preferably, in step (5), the amount of the binder added is 2-5wt% of the ceramic material obtained in step S3; after the binder is added, the mixture is mixed, granulated, pressed and sintered in sequence to obtain an intermediate microwave dielectric ceramic material.

[0015] Preferably, in step (5), the pressing is performed to form an embryo body according to the shape of the final product; the pressing pressure is 100-500 MPa.

[0016] Preferably, in step (5), the sintering temperature is 1250-1400° C. and the sintering time is 4-8 hours.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention adopts Sm 3+ For (Ca 1-x Sr x )TiO 3 The positive temperature coefficient phase ε in the material composition is adjusted by replacing r and τ f The linear relationship between Sm 3+ Partially substituted negative temperature coefficient phase YAlO 3 In combination with ceramics, a near-zero temperature coefficient can be obtained in a wider range of dielectric constants.

[0018] (2) The negative temperature coefficient phase YAlO in the present invention 3 ceramics belong to the high-temperature phase and are prone to form Y 3 Al 5 O 12 heterophase during the sintering process. By partially substituting Y with Sm 3+ , the synthesis of the single-phase YAlO 3+ can be promoted at a relatively low temperature, thereby avoiding the formation of the second phase and contributing to obtaining a moderate dielectric constant and a near-zero temperature coefficient. 3

[0019] (3) The sintering aid added in the present invention infiltrates the main-phase grains by forming a liquid phase during the sintering process, promotes the rearrangement of the powder particles, and achieves a dense spatial packing effect at a lower temperature. On the other hand, it can also promote the dissolution of small particles with sharp edges in the green body in the liquid phase, and realize the crystallization on the surface of the coarse particles through liquid-phase diffusion, significantly accelerating the reaction process.

[0020] (4) By synergistically regulating the main-phase ceramics and the sintering aid, the obtained material can be sintered densely in a relatively low intermediate temperature range (1330 - 1400 °C), and has a moderate dielectric constant (ε r = 36 - 42), the quality factor Q×f reaches more than 34000 GHz, the temperature coefficient τ f is nearly zero and adjustable, has a certain low-energy consumption advantage, and has great practical value. Moreover, the preparation process is simple, has good repeatability, low energy consumption, low raw material cost, and can be used to prepare products such as dielectric resonators for base stations and dielectric filters for 5G small base stations. Description of the Drawings

[0021] Figure 1 It is the scanning electron microscope image of the intermediate microwave dielectric ceramic material prepared in Example 9. Detailed Embodiments

[0022] The following specific examples are used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto.

[0023] Comparative Example 1 The preparation method of the ceramic material includes the following steps: (1) Weigh the raw materials CaCO 3 and TiO 3 according to the stoichiometric ratio in CaTiO 2 , add deionized water according to the mass ratio of material to water of 1:1.8, mix wet for 24 h, then dry at 120 °C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1150 °C for 4 h to synthesize the main crystal phase, grind and pass through a 40-mesh sieve as the main-phase ceramic I for standby.

[0024] (2) According to YAlO3 Weigh Y in the stoichiometric ratio 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0025] (3) The prepared main phase ceramic I and main phase ceramic II are mixed in a mass ratio of 65.3%:34.7%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0026] (4) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1650° C. for 4 h.

[0027] Comparative Example 2 The method for preparing the ceramic material comprises the following steps: (1) According to CaTiO 3 Weigh the raw material CaCO in the stoichiometric ratio 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0028] (2) Press YAlO 3 Weigh Y in the stoichiometric ratio 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0029] (3) According to 41.2wt%SiO 2 -32.6wt%Al 2 O 3 -26.2wt%TiO 2 Weigh the raw material SiO 2 、Al 2 O 3 、TiO2 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0030] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 65.3%:34.7%:0.5%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0031] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1650° C. for 4 h.

[0032] Example 1 The method for preparing the ceramic material comprises the following steps: (1) According to CaTiO 3 Weigh the raw material CaCO in the stoichiometric ratio 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0033] (2) Press YAlO 3 Weigh Y in the stoichiometric ratio 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0034] (3) According to 41.2wt% SiO 2 -32.6wt%Al 2 O 3 -26.2wt%SrCO 3 Weigh the raw material SiO in the stoichiometric ratio 2 、Al 2 O 3 、SrCO3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0035] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 65.3%:34.7%:0.5%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0036] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1375° C. for 4 h.

[0037] Example 2 The method for preparing the ceramic material comprises the following steps: (1) Press Ca 0.74 Sm 0.52 / 3 TiO 3 Weigh the raw material CaCO 3 、Sm 2 O 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0038] (2) Press YAlO 3 Weigh Y in the stoichiometric ratio 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0039] (3) According to 41.2wt%SiO 2 -32.6wt%Al 2 O 3 -26.2wt%SrCO 3 Weigh the raw material SiO in the stoichiometric ratio2 、Al 2 O 3 、SrCO 3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0040] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 65.3%:34.7%:0.5%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0041] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1375° C. for 4 h.

[0042] Example 3 The method for preparing the ceramic material comprises the following steps: (1) According to CaTiO 3 Weigh the raw material CaCO in the stoichiometric ratio 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0043] (2) Press Y 0.9 Sm 0.1 AlO 3 Weigh the raw material Sm 2 O 3 , Y 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0044] (3) According to 41.2wt%SiO 2 -32.6wt%Al 2 O3 -26.2wt%SrCO 3 Weigh the raw material SiO in the stoichiometric ratio 2 、Al 2 O 3 、SrCO 3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0045] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 65.3%:34.7%:0.5%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0046] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1375° C. for 4 h.

[0047] Example 4 The method for preparing the ceramic material comprises the following steps: (1) Press Ca 0.74 Sm 0.52 / 3 TiO 3 Weigh the raw material CaCO 3 、Sm 2 O 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0048] (2) Press Y 0.74 Sm 0.26 AlO 3 Weigh the raw material Sm 2 O 3 , Y 2 O 3 and Al 2 O 3, add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0049] (3) According to 41.2wt% SiO 2 -32.6wt%Al 2 O 3 -26.2wt%SrCO 3 Weigh the raw material SiO in the stoichiometric ratio 2 、Al 2 O 3 、SrCO 3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0050] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 65.3%:34.7%:0.5%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0051] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1375° C. for 4 h.

[0052] Example 5 The method for preparing the ceramic material comprises the following steps: (1) Press Ca 0.74 Sm 0.52 / 3 TiO 3 Weigh the raw material CaCO 3 、Sm 2 O 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0053] (2) Press Y 0.9 Sm 0.1 AlO3 Weigh the raw material Sm 2 O 3 , Y 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0054] (3) According to 35.8wt% SiO 2 -26.8wt%Al 2 O 3 -25.5wt%SrCO 3 -3.7wt%TiO 2 -8.2wt%B 2 O 3 Weigh the raw material SiO in the stoichiometric ratio 2 、Al 2 O 3 、SrCO 3 、TiO 2 、ZrO 2 and H 3 BO 3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0055] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 53.97%:46.03%:0.3%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0056] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1375° C. for 4 h.

[0057] Example 6 The method for preparing the ceramic material comprises the following steps: (1) Press (Ca 0.8 Sr 0.2 ) 0.74Sm 0.52 / 3 TiO 3 Weigh the raw material CaCO 3 、SrCO 3 、Sm 2 O 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0058] (2) Press Y 0.9 Sm 0.1 AlO 3 Weigh the raw material Sm 2 O 3 , Y 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0059] (3) According to 34.4wt% SiO 2 -25.2wt%Al 2 O 3 -25.0wt%SrCO 3 -1.4wt%ZrO 2 -1.8wt%TiO 2 -12.2wt%B 2 O 3 Weigh the raw material SiO in the stoichiometric ratio 2 、Al 2 O 3 、SrCO 3 、TiO 2 、ZrO 2 and H 3 BO 3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0060] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 46.9%:53.1%:0.6%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0061] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1350° C. for 4 h.

[0062] Example 7 The method for preparing the ceramic material comprises the following steps: (1) Press (Ca 0.9 Sr 0.1 ) 0.9 Sm 0.2 / 3 TiO 3 Weigh the raw material CaCO 3 、SrCO 3 、Sm 2 O 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0063] (2) Press Y 0.8 Sm 0.2 AlO 3 Weigh the raw material Sm 2 O 3 , Y 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0064] (3) According to 33.4wt% SiO 2 -23.8wt%Al 2 O 3 -24.8wt%SrCO 3 -1.4wt%ZrO 2 -1.8wt%TiO 2 -14.8wt%B 2 O 3 Weigh the raw material SiO in the stoichiometric ratio2 、Al 2 O 3 、SrCO 3 、TiO 2 、ZrO 2 and H 3 BO 3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0065] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 62.5%:37.5%:0.4%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0066] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the pellets were pressed at 100 MPa into cylindrical bodies with a diameter of 20 mm and a thickness of 8 to 9 mm, and then kept at 1400° C. for 4 h.

[0067] Example 8 The method for preparing the ceramic material comprises the following steps: (1) Press (Ca 0.9 Sr 0.1 ) 0.9 Sm 0.2 / 3 TiO 3 Weigh the raw material CaCO 3 、SrCO 3 、Sm 2 O 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0068] (2) Press Y 0.9 Sm 0.1 AlO 3 Weigh the raw material Sm 2 O 3 , Y 2 O 3 and Al 2 O 3, add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0069] (3) According to 34.4wt% SiO 2 -25.2wt%Al 2 O 3 -25.0wt%SrCO 3 -1.4wt%ZrO 2 -1.8wt%TiO 2 -12.2wt%B 2 O 3 Weigh the raw material SiO in the stoichiometric ratio 2 、Al 2 O 3 、SrCO 3 、TiO 2 、ZrO 2 and H 3 BO 3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0070] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 57.5%:42.5%:0.3%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0071] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1350° C. for 4 h.

[0072] Example 9 The method for preparing the ceramic material comprises the following steps: (1) Press (Ca 0.8 Sr 0.2 ) 0.9 Sm 0.2 / 3 TiO 3 Weigh the raw material CaCO 3 、SrCO 3 、Sm2 O 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0073] (2) Press Y 0.9 Sm 0.1 AlO 3 Weigh the raw material Sm 2 O 3 , Y 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0074] (3) According to 35.8wt% SiO 2 -26.8wt%Al 2 O 3 -25.5wt%SrCO 3 -3.7wt%TiO 2 -8.2wt%B 2 O 3 Weigh the raw material SiO in the stoichiometric ratio 2 、Al 2 O 3 、SrCO 3 、TiO 2 、ZrO 2 and H 3 BO 3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0075] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 53.5%:46.5%:0.3%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0076] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1350° C. for 4 h.

[0077] Example 10 The method for preparing the ceramic material comprises the following steps: (1) Press (Ca 0.93 Sr 0.07 ) 0.9 Sm 0.2 / 3 TiO 3 Weigh the raw material CaCO 3 、SrCO 3 、Sm 2 O 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0078] (2) Press Y 0.9 Sm 0.1 AlO 3 Weigh the raw material Sm 2 O 3 , Y 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0079] (3) According to 34.4wt% SiO 2 -25.2wt%Al 2 O 3 -25.0wt%SrCO 3 -1.4wt%ZrO 2 -1.8wt%TiO 2 -12.2wt%B 2 O 3 Weigh the raw material SiO in the stoichiometric ratio 2 、Al 2 O 3 、SrCO 3 、TiO 2 、ZrO 2 and H 3 BO3 , add anhydrous ethanol at a mass ratio of 1:1.5 between the mixture and anhydrous ethanol, wet mix for 18 hours and then dry at 80°C, pass the dried mixture through a 250-mesh sieve, put it into a crucible and heat it to 1000°C at 5°C / min, then heat it to 1550°C at 3°C / min and melt it for 1 hour, then pour the melt into deionized water at room temperature to quench, crush and grind the obtained glass slag and pass it through a 250-mesh sieve to obtain a sintering aid for use.

[0080] (4) The prepared main phase ceramic I, main phase ceramic II and sintering aid are mixed in a mass ratio of 53.5%:46.5%:0.6%, and deionized water is added in a material-water mass ratio of 1:1.2. After wet mixing for 18 hours, the mixture is dried at 120°C to obtain a ceramic material.

[0081] (5) 3 wt % polyvinyl alcohol (PVA) binder was added to the ceramic material for granulation, and the granulated product was pressed into a cylindrical body with a diameter of 20 mm and a thickness of 8 to 9 mm at 100 MPa, and kept at 1330° C. for 4 h.

[0082] Embodiment 11 The method for preparing the ceramic material comprises the following steps: (1) Press (Ca 0.9 Sr 0.1 ) 0.9 Sm 0.2 / 3 TiO 3 Weigh the raw material CaCO 3 、SrCO 3 、Sm 2 O 3 and TiO 2 , add deionized water at a material-water mass ratio of 1:1.8, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine it at 1150°C for 4 hours to synthesize the main crystalline phase, grind it and pass it through a 40-mesh sieve as the main phase ceramic I for later use.

[0083] (2) Press Y 0.8 Sm 0.2 AlO 3 Weigh the raw material Sm 2 O 3 , Y 2 O 3 and Al 2 O 3 , add deionized water at a material-water mass ratio of 1:1.5, wet mix for 24 hours and then dry at 120°C, pass the dried mixture through a 40-mesh sieve, put it into an alumina crucible, calcine at 1250°C for 4 hours to synthesize the main crystalline phase, grind and pass through a 40-mesh sieve as the main phase ceramic II for standby use.

[0084] (3) Weigh the raw materials SiO 2 -23.8 wt% Al 2 O 3 -24.8 wt% SrCO 3 -1.4 wt% ZrO 2 -1.8 wt% TiO 2 -14.8 wt% B 2 O 3 according to the stoichiometric ratio in (33.4 wt% SiO 2 , Al 2 O 3 , SrCO 3 , TiO 2 , ZrO 2 and H 3 BO 3 . Add absolute ethanol according to the mass ratio of the mixture to absolute ethanol of 1:1.5, mix the materials wet for 18 h and then dry at 80 °C. Pass the dried mixture through a 250-mesh sieve, load it into a crucible, first heat it to 1000 °C at a rate of 5 °C / min, then heat it to 1550 °C at a rate of 3 °C / min and melt for 1 h. Then pour the melt into deionized water at room temperature for quenching. After crushing and grinding the obtained glass slag, pass it through a 250-mesh sieve to obtain the sintering aid for standby.

[0085] (4) Mix the prepared matrix ceramics I, matrix ceramics II and sintering aid according to the mass ratio of 47.5%:52.5%:0.5%. Add deionized water according to the mass ratio of the material to water of 1:1.2, mix the materials wet for 18 h and then dry at 120 °C to obtain the ceramic material.

[0086] (5) Add 3 wt% polyvinyl alcohol (PVA) binder to the ceramic material for granulation, press it into a cylindrical green body with a diameter of 20 mm and a thickness of 8 - 9 mm at 100 MPa, and keep it at 1350 °C for 4 h.

[0087] The specific ratios of matrix ceramics I, matrix ceramics II and sintering aid in Comparative Examples 1 - 2 and Examples 1 - 11 are shown in Table 1 and Table 2 as follows.

[0088] Table 1 Table 2 Use the Archimedes drainage method to measure the bulk density of the sintered ceramic samples, and use an Agilent 8719ET network analyzer to test the dielectric constant ε according to the Hakki-Coleman resonant cavity method. rAnd Q×f value, the frequency temperature coefficient is tested in the temperature range of 25~85℃, and according to the formula τ f =(f 85 -f 25 ) / (f 25 ×60) is calculated and determined, where f 85 and f 25 are the center frequencies of the samples at 85°C and 25°C respectively.

[0089] Table 3 As shown in Table 3, by adding sintering aids, the sintering densification temperature of the ceramic materials obtained in Examples 1 to 11 above is significantly lower than that of Comparative Examples 1-2, and the ceramic materials have a relatively high Q×f value. 3+ Ca 2+ and Y 3+ With partial substitution of , a near-zero temperature coefficient can be obtained in the dielectric constant range of 36 to 42. Figure 1 As shown, Example 9 sintered at 1350°C has a dense microstructure.

[0090] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An intermediate microwave dielectric ceramic material, characterized in that: Including main phase ceramics and dominant phase ceramics p wt% sintering aid; the main phase ceramic is composed of m wt%(Ca 1-x Sr x ) 1-y Sm 2y / 3 TiO3 and n wt%Y 1-z Sm z AlO3 composition; the composition of the sintering aid is a wt% SiO2- b wt% Al2O3- c wt% SrCO3- d wt% ZrO2- e wt% TiO2- f wt%B2O3; Among them, 0< p ≤0.6; 46.5≤ m ≤73.0,27.0≤ n ≤53.5, m + n =100; 0≤ x ≤0.2,0≤ y ≤0.26,0≤ z ≤0.2; 30≤ a ≤45,20≤ b ≤35, 20≤ c ≤30,0≤ d ≤5,0≤ e ≤5,0≤ f ≤15, and a + b + c + d + e + f =100.

2. The intermediate microwave dielectric ceramic material according to claim 1, characterized in that: The sintering aid is prepared by mixing raw materials, melting at 1450-1550° C., and quenching; the raw materials include three or more of SiO2, Al2O3, SrCO3, TiO2, ZrO2, and H3BO3.

3. A method for preparing the intermediate microwave dielectric ceramic material according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) Press (Ca 1-x Sr x ) 1-y Sm 2y / 3 CaCO3, SrCO3, Sm2O3 and TiO2 were weighed in the stoichiometric ratio in TiO3, wet mixed, dried, sieved and calcined to obtain the main phase ceramic I; (2) Press Y 1-z Sm z Sm2O3, Y2O3 and Al2O3 are weighed in the stoichiometric ratio in AlO3, wet mixed, dried, sieved and calcined to obtain the main phase ceramic II; (3) Weighing SiO2, Al2O3, SrCO3, TiO2, ZrO2 and H3BO3 according to the stoichiometric ratio in the composition of the sintering aid, wet mixing, drying, sieving and melting, and then quenching to obtain a sintering aid; (4) mixing the main phase ceramic I, the main phase ceramic II and the sintering aid, performing wet mixing and drying; (5) After pressing and sintering, ceramic material is obtained.

4. The preparation method according to claim 3, characterized in that: In step (1), the material-water mass ratio in the wet mixing process is 1:1.5-2.5, and the mixing time is 16-24 hours.

5. The preparation method according to claim 3 or 4, characterized in that: In step (2), the calcination is performed at 1150-1200° C. for 2-4 hours.

6. The preparation method according to claim 3, characterized in that: In step (2), the material-water mass ratio in the wet mixing process is 1:1.5-2.0, and the mixing time is 16-24 hours.

7. The preparation method according to claim 3 or 6, characterized in that: In step (2), the calcination is carried out at 1200-1250° C. for 2-4 hours.

8. The preparation method according to claim 3, characterized in that: In step (3), the material-water mass ratio in the wet mixing process is 1:1.0-2.0, and the mixing time is 18-24 hours; the mesh size of the sieve is 200-300 meshes.

9. The preparation method according to claim 3 or 8, characterized in that: In step (3), the melting is firstly carried out by heating the temperature to 1000°C at a rate of 5-8°C / min, and then heating the temperature to 1450-1550°C at a rate of 1-3°C / min and melting for 1-2h.

10. The preparation method according to claim 3, characterized in that: In step (4), the material-water mass ratio in the wet mixing process is 1:1.0-1.5, and the mixing time is 12-18 hours.

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