Perovskite-based low-temperature co-fired ceramic and preparation method and application thereof

Abstract

The application discloses a perovskite-based low-temperature co-fired ceramic and a preparation method and application thereof. The low-temperature co-fired ceramic is composed of lithium-boron-silicon glass and CaTiO3, and the mass ratio of the lithium-boron-silicon glass to the CaTiO3 is (10-30):(90-70). The lithium-boron-silicon glass with a low softening point and a small high-temperature viscosity is obtained by selecting each component and controlling the proportion of each component, so as to reduce the sintering temperature of the perovskite, greatly reduce the required glass content for densifying the low-temperature co-fired ceramic, and improve the microwave dielectric properties of the low-temperature co-fired ceramic. Then, the dielectric constant of the low-temperature co-fired ceramic is regulated by controlling the composition and proportion of the low-temperature co-fired ceramic and the particle size of the ceramic. Compared with the current mainstream LTCC medium material, the dielectric constant of the perovskite-based low-temperature co-fired ceramic is higher, is 85-110, and simultaneously meets the low-temperature sintering requirement of the LTCC technology, so that the matching property of the low-temperature co-fired ceramic and a substrate material is better, and the actual application requirement is met.

Description

Technical Field

[0001] This invention relates to the field of electronic ceramic materials and their manufacturing technology, and in particular to a perovskite-based low-temperature co-fired ceramic and its preparation method and application. Background Technology

[0002] With the rapid development of communication technology, from the manufacturing of small portable terminals and artificial intelligence devices to the research and development of satellite communications and phased array radar, higher demands are being placed on the miniaturization, high-frequency operation, and multifunctionality of electronic devices and products. Low Temperature Co-fired Ceramics (LTCC) technology, as a high-density packaging technology based on multilayer ceramics, is the preferred solution to meet these needs. However, like other high-density integration technologies, LTCC technology also faces many difficulties in the integration of passive components (capacitors and inductors). As is well known, passive components have a significant impact on the size and reliability of electronic equipment. The large number of passive components, and the fact that the vast majority are mounted on the substrate surface, makes it difficult to further reduce the size of devices / assemblies and further increase the assembly density.

[0003] Integrating capacitors, inductors, and other components into LTCC multilayer substrates through pattern design and stacking processes can further improve assembly density. Specifically, passive components such as capacitors are embedded within the LTCC multilayer substrate, while components that cannot be integrated into the substrate, such as RF chips, MEMS, and microprocessors, are mounted on the substrate surface. Clearly, embedding passive components significantly reduces the number of surface-mount components and the assembly area, thereby substantially increasing assembly density.

[0004] LTCC substrate materials are generally selected with low dielectric constant (ε) r :5~8) Material systems are used to reduce signal delay time, but to achieve large-capacity embedded capacitors, higher ε is required. r The dielectric material. High ε r The dielectric material can be a green ceramic tape obtained by casting process or a dielectric slurry obtained by rolling. Both can be integrated into the LTCC substrate as embedded capacitors. The capacitance value can be achieved by adjusting the dielectric constant, interlayer thickness or area of ​​the dielectric material.

[0005] Currently, LTCC substrate materials with low dielectric constants are relatively mature, and several commercially available material systems have been developed. In contrast, LTCC material systems with high dielectric constants are relatively fewer. Besides being integrated into LTCC substrates as embedded capacitors, high dielectric constant LTCC materials can also be used to fabricate multilayer chip components, such as filters, microwave dielectric resonators, and dielectric antennas.

[0006] CaTiO3 ceramics have a high dielectric constant and a simple structure, making them suitable for preparing high-dielectric-constant LTCC materials. However, the sintering temperature of CaTiO3 ceramics is relatively high (>1400℃), which differs significantly from the sintering temperature of low-dielectric-constant LTCC substrate materials (<950℃). Therefore, it is necessary to further reduce the sintering temperature to meet the requirements of LTCC technology. Summary of the Invention

[0007] This invention provides a perovskite-based low-temperature co-fired ceramic, its preparation method, and its application, to meet the demand for high dielectric constant LTCC materials in multilayer ceramic embedded capacitors and multilayer chip components.

[0008] To achieve the above objectives, this invention proposes a perovskite-based low-temperature co-fired ceramic, which is composed of lithium borosilicate glass and CaTiO3, wherein the mass ratio of lithium borosilicate glass to CaTiO3 is (10-30):(90-70); the lithium borosilicate glass is composed of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO in a molar ratio of (30-50):(0-10):(30-50):(10-30):(0-5):(0-5).

[0009] To achieve the above objectives, the present invention also proposes a method for preparing perovskite-based low-temperature co-fired ceramics as described above, comprising the following steps:

[0010] S1: Weigh Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO in the molar ratio (30~50)∶(0~10)∶(30~50)∶(10~30)∶(0~5)∶(0~5), mix them evenly, and then heat and keep warm in air until molten glass is obtained. Pour the molten glass into deionized water to obtain lithium borosilicate glass slag.

[0011] S2: The lithium borosilicate glass slag is ball-milled, pressure-filtered, dried and sieved to obtain lithium borosilicate glass powder;

[0012] S3: Weigh CaCO3 and TiO2 in a molar ratio of approximately 1:1, mix them evenly, and then heat and keep warm in an air atmosphere to obtain pre-calcined CaTiO3 powder;

[0013] S4: The pre-calcined CaTiO3 powder is milled, dried and sieved to obtain nano CaTiO3 powder;

[0014] S5: Weigh the lithium borosilicate glass powder and nano CaTiO3 powder at a mass ratio of (10-30): (90-70), mix them, ball mill, filter and dry them, and then sieve them to obtain the raw material powder.

[0015] S6: The raw material powder is mixed with a polyvinyl alcohol solution, granulated, and pressed to obtain a green body;

[0016] S7: In an air atmosphere, the green body is heated from room temperature to 425~475℃ and held for 2~4 hours, then heated to 850~900℃ and held for sintering for 1~3 hours, and then cooled to room temperature in the furnace to obtain perovskite-based low-temperature co-fired ceramic.

[0017] To achieve the above objectives, this invention also proposes an application of perovskite-based low-temperature co-fired ceramics. The low-temperature co-fired ceramics described above, or those prepared by the methods described above, are applied to electronic components with high requirements for miniaturization and integration, such as embedded capacitors in low-temperature co-fired ceramic (LTCC) substrates. Compared to embedded capacitors prepared using conventional substrate materials (with electrodes fabricated on both sides of a portion of the substrate), this method can reduce the capacitor area by more than 80% for the same size capacitor.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] The perovskite-based low-temperature co-fired ceramic provided by this invention is composed of lithium borosilicate glass and CaTiO3, with a mass ratio of lithium borosilicate glass to CaTiO3 of (10-30):(90-70). The lithium borosilicate glass is composed of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3, and CaO in a molar ratio of (30-50):(0-10):(30-50):(10-30):(0-5):(0-5). This invention obtains lithium borosilicate glass with low softening point and low high-temperature viscosity by selecting and controlling the proportions of each component, thereby reducing the sintering temperature of perovskite and significantly reducing the glass content required for densification of the low-temperature co-fired ceramic, thus improving the microwave dielectric properties of the low-temperature co-fired ceramic. Furthermore, the dielectric constant is controlled by adjusting the composition and proportions of the low-temperature co-fired ceramic and the particle size of the ceramic. Compared to the current mainstream LTCC dielectric materials, the perovskite-based low-temperature co-fired ceramic of this invention has a higher dielectric constant of 85~110. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1The microstructures of CaTiO3 powders after different milling times are shown; where (a) represents milling for 0 h, (b) represents milling for 1 h, and (c) represents milling for 2 h.

[0022] Figure 2 The sintering shrinkage curves of lithium borosilicate A and B glass with CaTiO3 of different contents and particle sizes are shown. Among them, (a) is the sintering shrinkage curve of lithium borosilicate A with CaTiO3 of different contents and particle sizes, and (b) is the sintering shrinkage curve of lithium borosilicate B with CaTiO3 of different contents and particle sizes.

[0023] Figure 3 Dielectric properties of lithium borosilicate C and D glass with CaTiO3 of different contents and particle sizes are given; wherein, (a) is the dielectric property of lithium borosilicate C with CaTiO3 of different contents and particle sizes, and (b) is the dielectric property of lithium borosilicate D with CaTiO3 of different contents and particle sizes.

[0024] Figure 4 Sintering shrinkage curves of lithium borosilicate A and B glasses with CaTiO3 of different contents and particle sizes in multiphase ceramics;

[0025] Figure 5 Sintering shrinkage curves of lithium borosilicate C and D glasses with multiphase ceramics of different contents and particle sizes of CaTiO3.

[0026] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0029] Unless otherwise specified, all medicines / reagents used are commercially available.

[0030] This invention proposes a perovskite-based low-temperature co-fired ceramic, which is composed of lithium borosilicate glass and CaTiO3, wherein the mass ratio of lithium borosilicate glass to CaTiO3 is (10-30):(90-70); the lithium borosilicate glass is composed of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO in a molar ratio of (30-50):(0-10):(30-50):(10-30):(0-5):(0-5).

[0031] Preferably, the sintering temperature of the low-temperature co-fired ceramic is 850~900℃, the dielectric constant is 85~110, and the quality factor is 1367~3413 GHz.

[0032] Preferably, the softening point of the lithium borosilicate glass is 400~500℃.

[0033] This invention also proposes a method for preparing perovskite-based low-temperature co-fired ceramics as described above, comprising the following steps:

[0034] S1: Weigh Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO in the molar ratio (30~50)∶(0~10)∶(30~50)∶(10~30)∶(0~5)∶(0~5), mix them evenly, and then heat and keep warm in air until molten glass is obtained. Pour the molten glass into deionized water to obtain lithium borosilicate glass slag.

[0035] S2: The lithium borosilicate glass slag is ball-milled, pressure-filtered, dried and sieved to obtain lithium borosilicate glass powder;

[0036] S3: Weigh CaCO3 and TiO2 in a molar ratio of approximately 1:1, mix them evenly, and then heat and keep warm in an air atmosphere to obtain pre-calcined CaTiO3 powder;

[0037] S4: The pre-calcined CaTiO3 powder is milled, dried and sieved to obtain nano CaTiO3 powder;

[0038] S5: Weigh the lithium borosilicate glass powder and nano CaTiO3 powder at a mass ratio of (10-30): (90-70), mix them, ball mill, filter and dry them, and then sieve them to obtain the raw material powder.

[0039] S6: The raw material powder is mixed with a polyvinyl alcohol solution, granulated, and pressed to obtain a green body;

[0040] S7: In an air atmosphere, the green body is heated from room temperature to 425~475℃ and held for 2~4 hours to fully remove the binder. Then, the temperature is further increased to 850~900℃ and held for sintering for 1~3 hours. The green body is then cooled to room temperature in the furnace to obtain perovskite-based low-temperature co-fired ceramic.

[0041] Preferably, in step S1, the heating rate of the heating and heat preservation is 5~15℃ / min, the heating temperature is 1100~1200℃, and the heat preservation time is 1~3h.

[0042] Preferably, in step S1, the total molar amount of the lithium borosilicate glass raw materials Li2CO3, Bi2O3, B2O3 and SiO2 is 100%, and by molar fraction, Li2CO3, Bi2O3, B2O3 and SiO2 are 50%, 10%, 20% and 20%, respectively.

[0043] Preferably, in step S2, the particle size of the lithium borosilicate glass powder is 2~3μm to improve the density and uniformity of the multiphase ceramic, thereby making the prepared multiphase ceramic have better performance and higher quality.

[0044] Preferably, in step S2, the ball mill rotates at a speed of 500 rpm for 8 to 15 hours.

[0045] Preferably, in step S3, the heating rate of the heating and heat preservation is 5~15℃ / min, the heating temperature is 1225~1275℃, and the heat preservation time is 1~3h.

[0046] Preferably, in step S4, the milling time is 1-2 hours; by adjusting the particle size of CaTiO3 powder, its intrinsic sintering temperature is reduced, and the sintering temperature of the low-temperature co-fired ceramic is further reduced, thereby meeting the co-firing requirements with the low dielectric substrate material.

[0047] Preferably, in step S5, the raw material powder has a D50 of 120~150μm and a D90 of 200~300μm.

[0048] This invention also proposes an application of perovskite-based low-temperature co-fired ceramics, applying the aforementioned low-temperature co-fired ceramics or those prepared by the aforementioned methods to electronic components with high requirements for miniaturization and integration, such as embedded capacitors in low-temperature co-fired ceramic (LTCC) substrates. Compared to embedded capacitors prepared using conventional substrate materials (with electrodes fabricated on both sides of a portion of the substrate), this method can reduce the capacitor area by more than 80% to prepare capacitors of the same size.

[0049] Example 1

[0050] This embodiment provides a perovskite-based low-temperature co-fired ceramic, which is composed of lithium borosilicate glass and CaTiO3, as shown in Table 3. The mass ratio of lithium borosilicate glass to CaTiO3 is 20:80. The lithium borosilicate glass is composed of Li2CO3, Bi2O3, B2O3 and SiO2 in a molar ratio of 50:10:20:20, as shown in Table 1.

[0051] This embodiment also provides a method for preparing the above-mentioned perovskite-based low-temperature co-fired ceramic, including the following steps:

[0052] (1) First, Li2CO3, Bi2O3, B2O3 and SiO2 are used as raw materials. They are weighed and mixed evenly according to the proportions in Table 1. Then, the mixture is heated to 1150℃ in an open platinum crucible at a heating rate of 10℃ / min and held for 2 hours. After that, the molten glass is quickly poured into deionized water to obtain glass slag. The lithium borosilicate glass obtained by this method is a glass with a softening point of 470.3℃.

[0053] (2) The glass slag obtained in step (1) is mixed with agate balls and anhydrous ethanol in a weight ratio of 1:4:1.5. The mixture is then ball-milled in a ball mill at a speed of 500 rpm for 12 hours, filtered and dried, and then passed through a 200-mesh sieve to obtain lithium borosilicate glass powder.

[0054] (3) Weigh CaCO3 and TiO2 in a molar ratio of 1:1 and mix them evenly. Then, heat the mixture from room temperature to 1250℃ in an air atmosphere and keep it at that temperature for 2 hours to obtain pre-calcined CaTiO3 powder.

[0055] (4) The pre-calcined powder obtained in step (3) is milled for 2 hours and then dried, and then passed through a 200-mesh sieve to obtain nano-CaTiO3 powder. The particle size characteristics of CaTiO3 powder with different milling times are shown in Table 2. Figure 1 The figures show the microstructure of CaTiO3 powder after different milling times. As can be seen, milling effectively reduces the particle size of CaTiO3 powder. After 1 hour of milling, the CaTiO3 powder was successfully milled from the micrometer scale (D50 = 1.191 μm) to the nanometer scale (D50 = 0.129 μm). After 2 hours of milling, the D50 parameter of the CaTiO3 powder did not change significantly, but with prolonged milling time, larger particles could be milled into smaller ones, resulting in a more uniform particle size distribution and a significant decrease in the D90 parameter. This is because in the initial stage of milling, the ceramic particles collide with the zirconia beads at high speed, causing stress concentration within the particles and triggering brittle fracture, thus rapidly reducing the particle size. However, as the milling time increases, the particle surface is gradually smoothed, and the internal stress is relieved. At this point, the particles no longer undergo brittle fracture but instead experience microplastic deformation and fatigue failure, resulting in a narrower particle size and more uniform particle size.

[0056] (5) The lithium borosilicate glass powder obtained in steps (3) and (4) is mixed with nano-perovskite according to the formula ratio in Table 3. The mixture is ball-milled at 400 rpm for 2 hours, filtered and dried, and then passed through a 200-mesh sieve to obtain the raw material powder.

[0057] (6) The raw material powder obtained in step (5) is mixed with a polyvinyl alcohol (PVA) solution with a mass fraction of 5wt% and then granulated. The mixture is then pressed into a round sample with a diameter of 20mm and a thickness of 1mm under a uniaxial pressure of 80MPa, which is the green blank.

[0058] (7) The green body obtained in step (6) is placed in a muffle furnace and heated to 450°C in an air atmosphere at a heating rate of 5°C / min and held for 2 hours to fully remove the binder; then the temperature is raised to 875°C at a heating rate of 5°C / min and held for 1 hour before being cooled with the furnace to obtain a perovskite-based low-temperature co-fired ceramic with a high dielectric constant.

[0059] Examples 2-12

[0060] Examples 2-12 mainly focus on the composition of lithium borosilicate glass, the changes in the relative contents of lithium borosilicate glass, Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO, to illustrate the influence of raw materials and formulation on the dielectric properties of high dielectric ceramic materials.

[0061] A perovskite-based low-temperature co-fired ceramic with high dielectric constant is prepared mainly from lithium borosilicate glass and nano-perovskite as raw materials, as shown in Table 3. The lithium borosilicate glass is mainly prepared from Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO as raw materials, as shown in Table 1.

[0062] Example 2: The mass ratio of lithium borosilicate glass and nano-perovskite was 10:90; the molar ratio of Li2CO3, Bi2O3, B2O3 and SiO2 was 50:10:20:20;

[0063] Example 3: The mass ratio of lithium borosilicate glass and nano-perovskite was 30:70; the molar ratio of Li2CO3, Bi2O3, B2O3 and SiO2 was 50:10:20:20;

[0064] Example 4: The mass ratio of lithium borosilicate glass to nano-perovskite was 10:90; the molar ratio of Li2CO3, Bi2O3, B2O3 and SiO2 was 40:10:25:25;

[0065] Example 5: The mass ratio of lithium borosilicate glass and nano-perovskite was 20:80; the molar ratio of Li2CO3, Bi2O3, B2O3 and SiO2 was 40:10:25:25;

[0066] Example 6: The mass ratio of lithium borosilicate glass and nano-perovskite was 30:70; the molar ratio of Li2CO3, Bi2O3, B2O3 and SiO2 was 40:10:25:25;

[0067] Example 7: The mass ratio of lithium borosilicate glass to nano-perovskite is 10:90; the molar ratio of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO is 30:30:30:5:5;

[0068] Example 8: The mass ratio of lithium borosilicate glass to nano-perovskite was 20:80; the molar ratio of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO was 30:30:30:5:5;

[0069] Example 9: The mass ratio of lithium borosilicate glass and nano-perovskite is 30:70; the molar ratio of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO is 30:30:30:5:5;

[0070] Example 10: The mass ratio of lithium borosilicate glass to nano-perovskite was 10:90; the molar ratio of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO was 50:30:10:5:5;

[0071] Example 11: The mass ratio of lithium borosilicate glass to nano-perovskite is 20:80; the molar ratio of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO is 50:30:10:5:5;

[0072] Example 12: The mass ratio of lithium borosilicate glass to nano-perovskite is 30:70; the molar ratio of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO is 50:30:10:5:5;

[0073] The method for preparing high dielectric constant perovskite-based low-temperature co-fired ceramics in this embodiment includes the following steps:

[0074] (1) First, Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO were weighed and mixed evenly according to the proportions in Table 1. Then, the mixture was heated to 1150℃ in an open platinum crucible at a heating rate of 10℃ / min and held for 2 hours. After that, the molten glass was quickly poured into deionized water to obtain glass slag. The lithium borosilicate glass obtained by this method is called glass. The softening point of the lithium borosilicate glass is shown in Table 1.

[0075] (2) The glass slag obtained in step (1) is mixed with agate balls and anhydrous ethanol in a weight ratio of 1:4:1.5. The mixture is then ball-milled in a ball mill at a speed of 500 rpm for 12 hours, filtered and dried, and then passed through a 200-mesh sieve to obtain lithium borosilicate glass powder.

[0076] (3) Weigh CaCO3 and TiO2 in a molar ratio of 1:1 and mix them evenly. Then, heat the mixture from room temperature to 1250℃ in an air atmosphere and keep it at that temperature for 2 hours to obtain pre-calcined CaTiO3 powder.

[0077] (4) The pre-calcined powder obtained in step (3) is sand-milled for 2 hours and then dried, and then passed through a 200-mesh sieve to obtain nano CaTiO3 powder;

[0078] (5) The lithium borosilicate glass powder obtained in step (4) is mixed with perovskite according to the formula ratio in Table 3. The mixture is ball-milled at 400 rpm for 2 hours, filtered and dried, and then passed through a 200-mesh sieve to obtain the raw material powder.

[0079] (6) The raw material powder obtained in step (5) is mixed with a polyvinyl alcohol (PVA) solution with a mass fraction of 5wt% and then granulated. The mixture is then pressed into a round sample with a diameter of 20mm and a thickness of 1mm under a uniaxial pressure of 80MPa, which is the green blank.

[0080] (7) The green body obtained in step (6) is placed in a muffle furnace and heated to 450°C in an air atmosphere at a heating rate of 5°C / min and held for 2 hours to fully remove the binder; then the temperature is raised to 875°C at a heating rate of 5°C / min and held for 1 hour before being cooled with the furnace to obtain a perovskite-based low-temperature co-fired ceramic with a high dielectric constant.

[0081] Figure 2 The figure shows the sintering shrinkage curves of multiphase ceramics formed by lithium borosilicate glasses A and B with CaTiO3 of different contents and particle sizes. In the figure, x%y-zCT represents the sample number, x represents the glass content added to the multiphase ceramic, y represents the type of glass added, and z represents the D90 parameter of the CaTiO3 ceramic powder. As shown in the figure, the sintering shrinkage curves of CaTiO3 ceramics with 10-20 wt% A / B glass after sand milling are comparable to those with 30 wt% A / B glass added before sand milling. This indicates that sand milling of CaTiO3 ceramics can significantly reduce the initial shrinkage temperature and increase the maximum shrinkage rate of the multiphase ceramics, demonstrating that sand milling can effectively reduce the sintering temperature of multiphase ceramics and is beneficial for ceramic sintering.

[0082] Figure 3The dielectric properties of multiphase ceramics formed by lithium borosilicate glass (C / D) with CaTiO3 of different contents and particle sizes are shown in the figure. As can be seen from the figure, x%y-zCT represents the sample number, x represents the glass content added to the multiphase ceramic, y represents the type of glass added, and z represents the D90 parameter of the CaTiO3 ceramic powder. The figure shows that the sintering shrinkage curves of CaTiO3 ceramics with 10-20 wt% C / D glass after sand milling are comparable to those with 30 wt% C / D glass before sand milling. This indicates that sand milling of CaTiO3 ceramics can significantly reduce the initial shrinkage temperature and increase the maximum shrinkage rate of the multiphase ceramics, demonstrating that sand milling can effectively reduce the sintering temperature of multiphase ceramics and is beneficial for ceramic sintering.

[0083] Figure 4 The figure shows the sintering shrinkage curves of multiphase ceramics formed by lithium borosilicate glasses A and B with CaTiO3 of different contents and particle sizes. As can be seen from the figure, sand milling not only reduces the glass content required for densification of the multiphase ceramics, but also significantly improves the dielectric properties of the multiphase ceramics. The dielectric properties of the multiphase ceramics with added glass A are shown to be... ε r =66, Q×f =2257 GHz increased to ε r =110, Q×f =3048 GHz; the dielectric properties of the multiphase ceramic with added B glass are... ε r =48, Q×f =2426 GHz increased to ε r =84, Q×f =1994GHz.

[0084] Figure 5 The figure shows the sintering shrinkage curves of multiphase ceramics formed by lithium borosilicate glasses C and D with CaTiO3 of different contents and particle sizes. As can be seen from the figure, sand milling not only reduces the glass content required for densification of the multiphase ceramics, but also significantly improves the dielectric properties of the multiphase ceramics. The dielectric properties of the multiphase ceramics with added C glass are shown to be... ε r =59, Q×f =1669 GHz increased to ε r =93, Q×f =1367 GHz; the dielectric properties of the multiphase ceramic with added D glass are... ε r =66, Q×f =2237 GHz increased to ε r =95, Q×f =3263GHz.

[0085] The low-temperature co-fired ceramics prepared in each embodiment were tested, and the dielectric properties of the ceramic samples were tested using the American resonant cavity method. The results are shown in Table 3. Lithium borosilicate glass exhibits good wettability to CaTiO3, and can coat ceramic particles at high temperatures, accelerating mass transfer and rearrangement, thereby reducing the sintering temperature of the ceramics. Simultaneously, by changing the composition of the Li2O-Bi2O3-B2O3-SiO2 glass system, the thermodynamic properties of the glass were adjusted, and A, B, C, and D glasses with excellent sintering aid effects were screened, enabling ceramic densification at low temperatures. Furthermore, by reducing the particle size of CaTiO3 ceramic powder from micrometers to nanometers through a sand milling process, the sintering temperature of the multiphase ceramics can be lowered, and the amount of glass required for densification can be reduced. Finally, a series of multiphase ceramics with excellent dielectric properties were successfully sintered at 850–900℃ using a solid-state reaction method, resulting in a series of multiphase ceramics with excellent dielectric properties. The final dielectric properties of the multiphase ceramics increased from […]. ε r =48~67, Q×f =2257~3098 GHz increased to ε r =85~110, Q×f =1367~3413 GHz.

[0086] Table 1. Raw material composition and softening point of lithium borosilicate glass

[0087]

[0088] Table 2. Particle size characteristics of CaTiO3 powder at different milling times

[0089]

[0090] Table 3. Raw material ratios and properties of the low-temperature co-fired ceramics in Examples 1-12

[0091]

[0092] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A perovskite-based low-temperature co-fired ceramic, characterized in that, The low-temperature co-fired ceramic is composed of lithium borosilicate glass and CaTiO3, wherein the mass ratio of the lithium borosilicate glass to CaTiO3 is (10-30):(90-70); the lithium borosilicate glass is composed of Li2CO3, Bi2O3, B2O3, SiO2, Al2O3, and CaO in a molar ratio of (30-50):(0-10):(30-50):(10-30):(0-5):(0-5). 3、 Al2O3 and CaO are not both zero; The sintering temperature of the low-temperature co-fired ceramic is 850~900℃, the dielectric constant is 85~110, and the quality factor is 1367~3413GHz; The softening point of the lithium borosilicate glass is 400~500℃; The preparation method of the perovskite-based low-temperature co-fired ceramic includes the following steps: S1: Weigh Li2CO3, Bi2O3, B2O3, SiO2, Al2O3 and CaO in a molar ratio of (30-50):(0-10):(30-50):(10-30):(0-5):(0-5), mix them evenly, and then heat and hold them in an air atmosphere until molten glass is obtained. Pour the molten glass into deionized water to obtain lithium borosilicate glass slag. The heating rate of the heating and holding is 5-15℃ / min, the heating temperature is 1100-1200℃, and the holding time is 1-3h. S2: The lithium borosilicate glass slag is ball-milled, pressure-filtered, dried and sieved to obtain lithium borosilicate glass powder with a particle size of 2~3μm; S3: Weigh CaCO3 and TiO2 in a molar ratio of 1:1, mix them evenly, and then heat and keep warm in an air atmosphere to obtain pre-calcined CaTiO3 powder. The heating rate of the heating and keeping warm is 5~15℃ / min, the heating temperature is 1225~1275℃, and the holding time is 1~3h. S4: The pre-calcined CaTiO3 powder is milled, dried, and sieved to obtain nano-CaTiO3 powder. The milling time is 1-2 hours. S5: The lithium borosilicate glass powder and nano-CaTiO3 powder are weighed at a mass ratio of (10-30):(90-70), mixed, ball-milled, filtered, dried, and then sieved to obtain the raw material powder. S6: The raw material powder is mixed with a polyvinyl alcohol solution, granulated, and pressed to obtain a green body; S7: In an air atmosphere, the green body is heated from room temperature to 425~475℃ and held for 2~4 hours, then heated to 850~900℃ and held for sintering for 1~3 hours, and then cooled to room temperature in the furnace to obtain perovskite-based low-temperature co-fired ceramic.

2. The perovskite-based low-temperature co-fired ceramic according to claim 1, characterized in that, In step S5, the raw material powder has a D50 of 120~150μm and a D90 of 200~300μm.

3. An application of a perovskite-based low-temperature co-fired ceramic, characterized in that, The low-temperature co-fired ceramics described in claim 1 or 2 are applied to electronic components.

Images