Environment-friendly middle-high dielectric constant ltcc ceramic material and preparation method thereof

Abstract

The application discloses an environment-friendly medium-high dielectric constant LTCC ceramic material and a preparation method thereof. 1.0 Nb 0.6 Ti 0.5 O3 and Li2CO3-B2O3-Bi2O3-SiO2 glass is compounded by a solid phase reaction method to obtain the LTCC ceramic material, and the problems of low-temperature sintering and adjustment of a resonance frequency temperature coefficient are solved, and meanwhile, a relatively high material dielectric constant is maintained. In the case that the Li2CO3-B2O3-Bi2O3-SiO2 glass is added as a fluxing agent, the material system is sintered at a low temperature in the range of 850 DEG C to 925 DEG C, meanwhile, the resonance frequency temperature coefficient of the material can be adjusted to be within ±5ppm / DEG C, the dielectric constant of the material is between 53 and 62, and the Qxf value is more than 6000GHz. The LTCC ceramic material has a relatively low sintering temperature and better compactness, and meanwhile, low-temperature co-sintering with Ag can be realized.

Description

Technical Field

[0001] This invention relates to the field of microwave dielectric ceramic materials technology, specifically to an environmentally friendly medium-high dielectric constant LTCC ceramic material and its preparation method. Background Technology

[0002] Microwave dielectric ceramic materials, as a key material for electronic components, are widely used in the fabrication of ceramic plates, ceramic capacitors, dielectric resonators, dielectric filters, and other electronic components. However, with the rapid development of communication and electronic information technology, the demand for highly efficient, miniaturized, and highly stable devices is increasing. Against this backdrop, LTCC (Low Temperature Co-fired Ceramic) technology has developed rapidly and become the most mainstream passive integration technology. LTCC material is an important branch of microwave dielectric ceramics; it is a multilayer ceramic packaging technology that embeds microwave devices within a ceramic substrate to form multilayer microwave circuits, facilitating the miniaturization, integration, and high reliability of microwave devices. However, LTCC technology typically uses environmentally friendly low-melting-point metals (usually Ag or Cu) as embedded electrodes. Therefore, to achieve co-firing between the dielectric substrate and the metal electrode, the melting point of the LTCC material should be lower than the melting point of the metal electrode (less than 950℃) and should not chemically react with the electrode. However, the sintering temperature of the more mature microwave dielectric ceramic systems is generally high (greater than 1300℃). Therefore, compared with traditional microwave dielectric ceramic materials, LTCC microwave dielectric materials sintered at 950℃ are more energy-efficient and environmentally friendly, and have greater performance advantages.

[0003] Microwave dielectric ceramic materials can be classified according to their dielectric constant into giant dielectric materials, high dielectric materials, medium dielectric materials, and low dielectric materials (for microwave applications). 1.0 Nb 0.6 Ti 0.5 O3 ceramics were discovered by MEVillafuerte et al. in 1987 through a systematic study of the phase diagram of the Li2O-Nb2O5-TiO2 ternary system. 1+x-y Nb 1-x-3y Ti x+4y O3 is one of the materials in the O3 system, belonging to microwave dielectric ceramic materials with medium to high dielectric constants. It is mainly used as a substrate material for microwave devices such as resonators and filters used in microwave communication base stations. 1.0 Nb 0.6 Ti 0.5 O3 microwave dielectric ceramics have excellent microwave dielectric properties (ε) r =64.79, Q×f=6385GHz, τ f=+8ppm / ℃), is an electronic information material with potential applications. However, its development in fields such as communication and electronic information technology is limited by its high sintering temperature, relatively large temperature coefficient of resonant frequency, and high production cost. 1.0 Nb 0.6 Ti 0.5 O3 ceramics, due to their inherent lithium ion content, have a relatively low densification sintering temperature (1100℃) without any sintering aids. However, LTCC technology requires the ceramic dielectric to be co-fired with metals such as Ag or Cu. Therefore, to ensure compatibility with the LTCC process, the sintering temperature of the dielectric ceramic must be lowered to below 960℃. However, reducing the sintering temperature of ceramics while maintaining good microwave dielectric properties is a challenging problem, while also considering the chemical compatibility between the ceramic and the metal electrode. Doping ceramics with low-melting-point oxides and glass is currently the simplest and most effective method to reduce the sintering temperature. These sintering aids generate a liquid phase during sintering, which accelerates grain rearrangement and promotes grain growth during grain wetting, thereby promoting ceramic densification and lowering the sintering temperature. Although previous researchers have used V2O5 to reduce Li... 1.0 Nb 0.6 Ti 0.5 The sintering temperature of O3 ceramics was reduced to 900℃, but V2O5 is highly toxic, easily pollutes the environment during production, and the temperature coefficient of the resonant frequency of the obtained ceramic samples is too large. Summary of the Invention

[0004] The purpose of this invention is to provide an environmentally friendly medium-high dielectric constant LTCC ceramic material and its preparation method, so as to solve the difficulties in the prior art in maintaining good microwave dielectric properties and low ceramic sintering temperature while being environmentally friendly.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides an environmentally friendly medium-high dielectric constant LTCC ceramic material, which comprises, by weight percentage, the following components: x% Li2CO3-B2O3-Bi2O3-SiO2 glass powder and (100-x)% Li 1.0 Nb 0.6 Ti 0.5 O3 ceramic powder, where 1≤x≤5.

[0007] Furthermore, the environmentally friendly medium-high dielectric constant LTCC ceramic material comprises, by weight percentage: 4% Li₂CO₃-B₂O₃-Bi₂O₃-SiO₂ glass powder and 96% Li 1.0 Nb 0.6 Ti0.5 O3 ceramic powder.

[0008] Furthermore, the molar ratio of Li2CO3, B2O3, Bi2O3, and SiO2 in the Li2CO3-B2O3-Bi2O3-SiO2 glass powder is 2:2:1:1.

[0009] Furthermore, the environmentally friendly medium-high dielectric constant LTCC ceramic material has a sintering temperature range of 850℃~925℃, a dielectric constant of 53~62, a Q×f value of 6000~8000GHz, and a resonant frequency temperature coefficient of -5~5ppm / ℃.

[0010] This invention also provides a method for preparing an environmentally friendly medium-high dielectric constant LTCC ceramic material, comprising the following steps:

[0011] Step 1: Prepare analytical grade Li2CO3, Nb2O5, and TiO2 according to their stoichiometric ratio; then use a ball mill to perform a single ball milling process to ensure uniform mixing of the ingredients. During ball milling, add deionized water to the ball mill container at a ratio of 1.5:1:3, and mill at a speed of 250-300 r / min for 6-12 hours. After ball milling, remove the slurry and place it in a constant temperature drying oven at 85℃-100℃ for drying and use.

[0012] Step 2: Sift the powder obtained after drying in Step 1 through a 40-mesh sieve. After sieving, place it in a crucible and pre-fire it in a muffle furnace at 700℃~750℃ for 6 hours. After natural cooling in the furnace, Li is obtained. 1.0 Nb 0.6 Ti 0.5 O3 ceramic pre-fired material;

[0013] Step 3: Prepare the analytical grade raw materials by mixing them in a molar ratio of Li2CO3:B2O3:Bi2O3:SiO2 = 2:2:1:1; then use a ball mill to ball mill the materials once to ensure uniform mixing; during ball milling, add deionized water, raw materials and ball milling media in a ratio of 1.5:1:3 into the ball mill container, and ball mill at a speed of 250-300 r / min for 6-12 hours. After ball milling, take out the slurry and place it in a constant temperature drying oven at 85℃-100℃ for drying and use.

[0014] Step 4: The powder obtained after drying in Step 3 is sieved through a 40-mesh sieve. After sieving, it is placed in a crucible and melted in a muffle furnace at 1200℃ for 3 hours. The melt is then removed and quenched to obtain Li2CO3-B2O3-Bi2O3-SiO2 glass. The glass is then ground into powder using an agate grinder for later use.

[0015] Step 5: Combine the Li obtained in Step 2 and Step 4 1.0 Nb 0.6 Ti 0.5 O3 pre-calcined material and Li2CO3-B2O3-Bi2O3-SiO2 glass powder were mixed at (100-x)% Li 1.0 Nb 0.6 Ti 0.5 The ingredients, O3+x%Li2CO3-B2O3-Bi2O3-SiO2, were weighed and mixed according to the weight ratio. Then, the mixture was placed into a ball mill container at a mass ratio of 1.5:1:3 for the deionized water, ingredients, and ball milling media. The mixture was then placed into a ball mill and ball milled at 300 r / min for 6–12 h. The resulting slurry was then removed and dried in a constant temperature drying oven at 85℃–100℃ for later use.

[0016] Step 6: Add 12 wt.% PVA glue to the dried powder obtained in Step 5 to agglomerate the fine powder into small particles with good flowability. Then, sieve these small particles through 40-mesh and 120-mesh screens, select particles between 40-mesh and 120-mesh, and uniaxially dry press them at 15-20 MPa to obtain ceramic blanks.

[0017] Step 7: Place the ceramic body obtained in Step 6 into a muffle furnace, heat it to 300℃ at a heating rate of 2℃ / min and hold it for 2-4 hours to drain the water. Then heat it to 600℃ at a heating rate of 2℃ / min and hold it for 4-6 hours to remove the binder. Then heat it to 850℃-925℃ at a heating rate of 2℃ / min and hold it for 4 hours. Let it cool naturally to room temperature with the furnace and take out the test sample.

[0018] Based on the above technical solution, the embodiments of the present invention can produce at least the following technical effects:

[0019] (1) This invention uses Li2CO3-B2O3-Bi2O3-SiO2 glass powder in a certain proportion to react with Li 1.0 Nb 0.6 Ti 0.5 O3 ceramic doping can simultaneously solve the problems of low-temperature sintering and adjusting the temperature coefficient of the resonant frequency, while ensuring that the microwave dielectric properties of the material, such as dielectric constant and dielectric loss, are not degraded, thus realizing the Li 1.0 Nb 0.6 Ti 0.5 Low-temperature sintering of O3 ceramics. The sintering temperature range is 850℃~925℃, the dielectric constant is 53~62, the Q×f value is 6000~8000GHz, and the temperature coefficient of resonant frequency is -5~5ppm / ℃. The preparation process used is stable and mature; the process is pollution-free and suitable for industrial production, especially for this Li... 1.0 Nb 0.6Ti 0.5 O3 ceramics have the characteristic of a low sintering temperature range, which expands their application prospects in the LTCC field.

[0020] (2) In Li 1.0 Nb 0.6 Ti 0.5 O3 ceramics doped with an appropriate amount of Li2CO3-B2O3-Bi2O3-SiO2 glass can help Li 1.0 Nb 0.6 Ti 0.5 During the sintering process, O3 ceramics exhibit grain size growth, reduced intergranular porosity, and more uniform grain distribution. Even doping with a small amount of Li2CO3-B2O3-Bi2O3-SiO2 glass can accelerate the Li2O3 sintering process. 1.0 Nb 0.6 Ti 0.5 The sintering process of O3 ceramics promotes grain growth and increases the density of the ceramic, thereby reducing Li. 1.0 Nb 0.6 Ti 0.5 The sintering temperature of O3 ceramics. Specifically, the Li2CO3-B2O3-Bi2O3-SiO2 glass gradually melts into a liquid phase as the temperature rises (the melting point of Li2CO3-B2O3-Bi2O3-SiO2 glass is 825℃), and then enters the Li... 1.0 Nb 0.6 Ti 0.5 The liquid phase between O3 grains can promote grain growth, reduce porosity, and improve the density of ceramics. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this 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 this invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a flowchart of the preparation method of environmentally friendly medium-high dielectric constant LTCC ceramic material provided in the embodiments of the present invention;

[0023] Figure 2 This is a schematic diagram illustrating the preparation method of environmentally friendly medium-high dielectric constant LTCC ceramic material provided in this embodiment of the invention.

[0024] Figure 3 This is a SEM image of the environmentally friendly medium-high dielectric constant LTCC ceramic material provided in Embodiment 1 of the present invention;

[0025] Figure 4 This is a SEM image of the environmentally friendly medium-high dielectric constant LTCC ceramic material provided in Embodiment 2 of the present invention;

[0026] Figure 5 This is a SEM image of the environmentally friendly medium-high dielectric constant LTCC ceramic material provided in Embodiment 3 of the present invention;

[0027] Figure 6 This is a SEM image of the environmentally friendly medium-high dielectric constant LTCC ceramic material provided in Embodiment 4 of the present invention. Detailed Implementation

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0032] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0033] The present invention will be described in detail below with reference to embodiments:

[0034] Example 1

[0035] A method for preparing an environmentally friendly medium-high dielectric constant LTCC ceramic material includes the following steps:

[0036] Step 1: Prepare analytical grade Li₂CO₃, Nb₂O₅, and TiO₂ according to their stoichiometric ratio; then, use a ball mill to perform a single ball milling process to ensure uniform mixing. The ball milling process involves first adding deionized water, ingredients, and balls in a ratio of approximately 1.5:1:3 to the ball mill container, then placing them together in the ball mill and milling at 300 rpm for 6 seconds. The resulting slurry is then removed and placed in an 85°C constant temperature drying oven for drying and later use.

[0037] Step Two: The powder obtained after drying in Step One is sieved through a 40-mesh sieve. After sieving, it is placed in a crucible and then placed in a muffle furnace for pre-firing at 750℃ for 6 hours. After natural cooling in the furnace, Li is obtained. 1.0 Nb 0.6 Ti 0.5 O3 ceramic pre-fired material.

[0038] Step 3: Prepare the analytical grade raw materials by mixing them in a molar ratio of Li2CO3:B2O3:Bi2O3:SiO2 = 2:2:1:1. Then, use a ball mill to ball-mill the materials to ensure uniform mixing. The ball milling process involves first adding deionized water, raw materials, and ball milling media in a ratio of approximately 1.5:1:3 to the ball mill container, then placing them into the ball mill and ball-milling at 300 r / min for 6–12 hours. The resulting slurry is then removed and dried in a constant temperature drying oven at 85℃ for later use.

[0039] Step 4: The powder obtained after drying in Step 3 is sieved through a 40-mesh sieve. After sieving, it is placed in a crucible and then melted in a muffle furnace at 1200℃ for 3 hours. After that, the melt is removed from the furnace and quickly placed in room temperature deionized water for quenching to obtain Li2CO3-B2O3-Bi2O3-SiO2 glass. Then, the glass is ground into powder using an agate grinder for later use.

[0040] Step 5: Combine the Li obtained in Step 2 and Step 4 1.0 Nb 0.6 Ti 0.5 O3 pre-calcined material and Li2CO3-B2O3-Bi2O3-SiO2 glass powder were mixed at (100-x)% Li 1.0 Nb 0.6 Ti 0.5The ingredients, O3+x%Li2CO3-B2O3-Bi2O3-SiO2 (where 1≤x≤5), were weighed and mixed. Then, the mixture was placed into a ball mill container at a mass ratio of 1.5:1:3 for the deionized water, ingredients, and ball milling media. The mixture was then placed into a ball mill and ball milled at a speed of 300 r / min for 6 hours. The resulting slurry was then removed and dried in a constant temperature drying oven at 85℃ for later use.

[0041] Step 6: Add 12 wt.% PVA adhesive to the dried powder obtained in Step 5 to agglomerate the fine powder into small particles with good flowability. Then, sieve these small particles through 40-mesh and 120-mesh screens, select particles between 40-mesh and 120-mesh, and dry press them into shape at 15-20 MPa.

[0042] Step 7: Place the ceramic body obtained in Step 6 into a muffle furnace, heat it to 300℃ at a heating rate of 2℃ / min and hold for 2 hours to drain the water. Then heat it to 600℃ at a heating rate of 2℃ / min and hold for 4 hours to drain the binder. Then heat it to 850℃~925℃ at a heating rate of 2℃ / min and hold for 4 hours. Let it cool naturally to room temperature with the furnace and take out the test sample.

[0043] Example 2:

[0044] (1) Li2CO3, Nb2O5, and TiO2 are mixed in a molar ratio of Li2CO3:Nb2O5:TiO2 = 5:3:5. The mixture is added to the ball mill container according to the ratio of deionized water:mixture:balls of approximately 1.5:1:3. Then, the mixture is placed into the ball mill and ball milled at a speed of 250-300 r / min for 6-12 hours. The slurry obtained after ball milling is taken out and placed in a constant temperature drying oven at 85℃-100℃ for drying and use.

[0045] (2) The dried Li2CO3-Nb2O5-TiO2 mixed powder was sieved through a 40-mesh sieve, placed in a crucible, and then placed in a muffle furnace for pre-firing at 700℃~750℃ for 6 hours. After natural cooling in the furnace, Li was obtained. 1.0 Nb 0.6 Ti 0.5 O3 ceramic pre-fired material;

[0046] (3) Prepare analytical grade raw materials by mixing them in a molar ratio of Li2CO3:B2O3:Bi2O3:SiO2 = 2:2:1:1; then use a ball mill to ball mill the materials once to ensure uniform mixing. The ball milling process is as follows: first, add deionized water, raw materials and ball milling media in a ratio of approximately 1.5:1:3 to the ball mill container, then put them into the ball mill together and ball mill at a speed of 250-300 r / min for 6-12 hours. After ball milling, take out the slurry and place it in a constant temperature drying oven at 85℃-100℃ for drying and use.

[0047] (4) The dried Li2CO3-B2O3-Bi2O3-SiO2 mixed powder was sieved through a 40-mesh sieve and then placed in a crucible. It was then placed in a muffle furnace for melting at 1200℃ for 3 hours. After that, the melt was taken out of the furnace and quickly placed in room temperature deionized water for quenching to obtain Li2CO3-B2O3-Bi2O3-SiO2 glass. The glass was then ground into powder using an agate grinder for later use.

[0048] (5) The Li obtained from (2) and (4) 1.0 Nb 0.6 Ti 0.5 O3 pre-calcined material and Li2CO3-B2O3-Bi2O3-SiO2 glass powder were mixed at (100-x)% Li 1.0 Nb 0.6 Ti 0.5 The ingredients, O3+x%Li2CO3-B2O3-Bi2O3-SiO2 (where x=1), were weighed and mixed. Then, the mixture was placed into a ball mill container at a mass ratio of 1.5:1:3 for the deionized water, ingredients, and ball milling media. The mixture was then placed into a ball mill and ball milled at 300 r / min for 6–12 h. The resulting slurry was then removed and dried in a constant temperature drying oven at 85℃–100℃ for later use.

[0049] (6) Add 12wt.% PVA glue to the dry powder obtained in (5) to make the fine powder agglomerate into small particles with good flowability, and sieve these small particles through 40 mesh and 120 mesh screens, select particles between 40 mesh and 120 mesh and dry press them at 15-20 MPa.

[0050] (7) Place the ceramic body obtained in (6) into a muffle furnace, heat it to 300℃ at a heating rate of 2℃ / min and hold it for 2 to 4 hours to drain the water. Then heat it to 600℃ at a heating rate of 2℃ / min and hold it for 4 to 6 hours to drain the glue. Then heat it to 850℃ to 925℃ at a heating rate of 2℃ / min and hold it for 4 hours. Let it cool naturally to room temperature with the furnace and take out the test sample.

[0051] Example 3:

[0052] (1) Li2CO3, Nb2O5, and TiO2 are mixed in a molar ratio of Li2CO3:Nb2O5:TiO2 = 5:3:5. The mixture is added to the ball mill container according to the ratio of deionized water:mixture:balls of approximately 1.5:1:3. Then, the mixture is placed into the ball mill and ball milled at a speed of 250-300 r / min for 6-12 hours. The slurry obtained after ball milling is taken out and placed in a constant temperature drying oven at 85℃-100℃ for drying and use.

[0053] (2) The dried Li2CO3-Nb2O5-TiO2 mixed powder was sieved through a 40-mesh sieve, placed in a crucible, and then placed in a muffle furnace for pre-firing at 700℃~750℃ for 6 hours. After natural cooling in the furnace, Li was obtained. 1.0 Nb 0.6 Ti 0.5 O3 ceramic pre-fired material;

[0054] (3) Prepare analytical grade raw materials by mixing them in a molar ratio of Li2CO3:B2O3:Bi2O3:SiO2 = 2:2:1:1; then use a ball mill to ball mill the materials once to ensure uniform mixing. The ball milling process is as follows: first, add deionized water, raw materials and ball milling media in a ratio of approximately 1.5:1:3 to the ball mill container, then put them into the ball mill together and ball mill at a speed of 250-300 r / min for 6-12 hours. After ball milling, take out the slurry and place it in a constant temperature drying oven at 85℃-100℃ for drying and use.

[0055] (4) The dried Li2CO3-B2O3-Bi2O3-SiO2 mixed powder was sieved through a 40-mesh sieve and then placed in a crucible. It was then placed in a muffle furnace for melting at 1200℃ for 3 hours. After that, the melt was taken out of the furnace and quickly placed in room temperature deionized water for quenching to obtain Li2CO3-B2O3-Bi2O3-SiO2 glass. The glass was then ground into powder using an agate grinder for later use.

[0056] (5) The Li obtained from (2) and (4) 1.0 Nb 0.6 Ti 0.5 O3 pre-calcined material and Li2CO3-B2O3-Bi2O3-SiO2 glass powder were mixed at (100-x)% Li 1.0 Nb 0.6 Ti 0.5The ingredients, O3+x%Li2CO3-B2O3-Bi2O3-SiO2 (where x=3), were weighed and mixed. Then, the mixture was placed into a ball mill container at a mass ratio of 1.5:1:3 for the deionized water, ingredients, and ball milling media. The mixture was then placed into a ball mill and ball milled at 300 r / min for 6–12 h. The resulting slurry was then removed and dried in a constant temperature drying oven at 85℃–100℃ for later use.

[0057] (6) Add 12wt.% PVA glue to the dry powder obtained in (5) to make the fine powder agglomerate into small particles with good flowability, and sieve these small particles through 40 mesh and 120 mesh screens, select particles between 40 mesh and 120 mesh and dry press them at 15-20 MPa.

[0058] (7) Place the ceramic body obtained in (6) into a muffle furnace, heat it to 300℃ at a heating rate of 2℃ / min and hold it for 2 to 4 hours to drain the water. Then heat it to 600℃ at a heating rate of 2℃ / min and hold it for 4 to 6 hours to drain the glue. Then heat it to 850℃ to 925℃ at a heating rate of 2℃ / min and hold it for 4 hours. Let it cool naturally to room temperature with the furnace and take out the test sample.

[0059] Example 4:

[0060] (1) Li2CO3, Nb2O5, and TiO2 are mixed in a molar ratio of Li2CO3:Nb2O5:TiO2 = 5:3:5. The mixture is added to the ball mill container according to the ratio of deionized water:mixture:balls of approximately 1.5:1:3. Then, the mixture is placed into the ball mill and ball milled at a speed of 250-300 r / min for 6-12 hours. The slurry obtained after ball milling is taken out and placed in a constant temperature drying oven at 85℃-100℃ for drying and use.

[0061] (2) The dried Li2CO3-Nb2O5-TiO2 mixed powder was sieved through a 40-mesh sieve, placed in a crucible, and then placed in a muffle furnace for pre-firing at 700℃~750℃ for 6 hours. After natural cooling in the furnace, Li was obtained. 1.0 Nb 0.6 Ti 0.5 O3 ceramic pre-fired material;

[0062] (3) Prepare analytical grade raw materials by mixing them in a molar ratio of Li2CO3:B2O3:Bi2O3:SiO2 = 2:2:1:1; then use a ball mill to ball mill the materials once to ensure uniform mixing. The ball milling process is as follows: first, add deionized water, raw materials and ball milling media in a ratio of approximately 1.5:1:3 to the ball mill container, then put them into the ball mill together and ball mill at a speed of 250-300 r / min for 6-12 hours. After ball milling, take out the slurry and place it in a constant temperature drying oven at 85℃-100℃ for drying and use.

[0063] (4) The dried Li2CO3-B2O3-Bi2O3-SiO2 mixed powder was sieved through a 40-mesh sieve and then placed in a crucible. It was then placed in a muffle furnace for melting at 1200℃ for 3 hours. After that, the melt was taken out of the furnace and quickly placed in room temperature deionized water for quenching to obtain Li2CO3-B2O3-Bi2O3-SiO2 glass. The glass was then ground into powder using an agate grinder for later use.

[0064] (5) The Li obtained from (2) and (4) 1.0 Nb 0.6 Ti 0.5 O3 pre-calcined material and Li2CO3-B2O3-Bi2O3-SiO2 glass powder were mixed at (100-x)% Li 1.0 Nb 0.6 Ti 0.5 The ingredients, O3+x%Li2CO3-B2O3-Bi2O3-SiO2 (where x=5), were weighed and mixed. Then, the mixture was placed into a ball mill container at a mass ratio of 1.5:1:3 for the deionized water, ingredients, and ball milling media. The mixture was then placed into a ball mill and ball milled at 300 r / min for 6–12 h. The resulting slurry was then removed and dried in a constant temperature drying oven at 85℃–100℃ for later use.

[0065] (6) Add 12wt.% PVA glue to the dry powder obtained in (5) to make the fine powder agglomerate into small particles with good flowability, and sieve these small particles through 40 mesh and 120 mesh screens, select particles between 40 mesh and 120 mesh and dry press them at 15-20 MPa.

[0066] (7) Place the ceramic body obtained in (6) into a muffle furnace, heat it to 300℃ at a heating rate of 2℃ / min and hold it for 2 to 4 hours to drain the water. Then heat it to 600℃ at a heating rate of 2℃ / min and hold it for 4 to 6 hours to drain the glue. Then heat it to 850℃ to 925℃ at a heating rate of 2℃ / min and hold it for 4 hours. Let it cool naturally to room temperature with the furnace and take out the test sample.

[0067] Table 1 shows the dielectric constant ε corresponding to different x values ​​for the LTCC ceramic material of the present invention during sintering at 850℃~925℃. r Value, Q×f value, temperature coefficient of resonant frequency τ f value.

[0068] As can be seen from the embodiments, the LTCC ceramic material provided by the present invention is based on Li 1.0 Nb 0.6 Ti 0.5 O3-doped Li2CO3-B2O3-Bi2O3-SiO2 glass powder was obtained via a solid-state reaction method. When sintered at a low temperature near 925℃, it effectively balances high dielectric constant, high Q×f value, and near-zero τ. f It meets many technical requirements for LTCC ceramic materials, such as their value, and has a promising application prospect in the LTCC field.

[0069] Table 1 shows the Li sintering temperature at different sintering temperatures. 1.0 Nb 0.6 Ti 0.5 The effect of O3 doping with different x values ​​on the dielectric properties of LTCC ceramic materials

[0070]

Claims

1. An environmentally friendly medium-high dielectric constant LTCC ceramic material, characterized in that, The environmentally friendly medium-high dielectric constant LTCC ceramic material comprises the following components by weight percentage: x% Li2CO3-B2O3-Bi2O3-SiO2 glass powder and (100-x)% Li 1.0 Nb 0.6 Ti 0.5 O3 ceramic powder, wherein 1≤x≤5; the environmentally friendly medium-high dielectric constant LTCC ceramic material has a sintering temperature range of 850℃~925℃, a dielectric constant of 53~62, a Q×f value of 6000~8000 GHz, and a resonant frequency temperature coefficient of -5~5ppm / ℃.

2. The environmentally friendly medium-high dielectric constant LTCC ceramic material according to claim 1, characterized in that, The environmentally friendly, medium-high dielectric constant LTCC ceramic material comprises, by weight percentage: 4% Li₂CO₃-B₂O₃-Bi₂O₃-SiO₂ glass powder and 96% Li 1.0 Nb 0.6 Ti 0.5 O3 ceramic powder.

3. The environmentally friendly medium-high dielectric constant LTCC ceramic material according to claim 1, characterized in that, The molar ratio of Li2CO3, B2O3, Bi2O3, and SiO2 in the Li2CO3-B2O3-Bi2O3-SiO2 glass powder is 2:2:1:

1.

4. A method for preparing an environmentally friendly medium-high dielectric constant LTCC ceramic material, used to prepare the environmentally friendly medium-high dielectric constant LTCC ceramic material as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Analytical grade Li2CO3, Nb2O5, and TiO2 are ball-milled once according to the specified ratio to ensure uniform mixing. The resulting slurry is then removed and placed in a constant temperature drying oven at 85℃~100℃ for drying and later use. Step Two: The powder obtained after drying in Step One is sieved through a 40-mesh sieve. After sieving, it is placed in a crucible and pre-fired in a muffle furnace at a temperature of 700℃~750℃ for 6 hours. After natural cooling in the furnace, Li is obtained. 1.0 Nb 0.6 Ti 0.5 O3 ceramic pre-fired material; Step 3: Use analytical grade Li2CO3, B2O3, Bi2O3, and SiO2 raw materials according to the specified ratio, and then use a ball mill to ball mill them once to ensure that the ingredients are evenly mixed; take out the slurry obtained after ball milling and place it in a constant temperature drying oven at 85℃~100℃ for drying and use. Step 4: The powder obtained after drying in Step 3 is sieved, then melted at 1200℃ for 3 hours. The melt is then quenched to obtain Li2CO3-B2O3-Bi2O3-SiO2 glass. The glass is then ground into powder for later use. Step 5: Combine the Li obtained in Step 2 and Step 4 1.0 Nb 0.6 Ti 0.5 O3 pre-calcined material and Li2CO3-B2O3-Bi2O3-SiO2 glass powder were mixed at (100-x)% Li 1.0 Nb 0.6 Ti 0.5 The O3+x% Li2CO3-B2O3-Bi2O3-SiO2 mixture was weighed and batched. Then, the mixture was placed into a ball mill container at a mass ratio of 1.5:1:3 for the deionized water, the raw materials, and the ball milling media. The mixture was then placed into a ball mill and milled at 300 r / min for 6–12 h. The resulting slurry was then removed and dried in a constant temperature drying oven at 85℃–100℃ for later use. Step 6: Add 12 wt.% PVA adhesive to the dried powder obtained in Step 5 and then sieve it through 40 mesh and 120 mesh screens. Select particles between 40 mesh and 120 mesh and then dry press them at 15-20 MPa to obtain ceramic blanks. Step 7: Place the ceramic body obtained in Step 6 into a muffle furnace, heat it to 300℃ and hold it for 2-4 hours to drain the water, then heat it to 600℃ and hold it for 4-6 hours to remove the binder, then heat it to 850℃-925℃ and hold it for 4 hours. Let it cool naturally to room temperature with the furnace and take out the LTCC ceramic material.

5. The method for preparing the environmentally friendly medium-high dielectric constant LTCC ceramic material according to claim 4, characterized in that, In step one, the molar ratio of Li2CO3, Nb2O5, and TiO2 is 5:3:5, and in step three, the molar ratio of Li2CO3:B2O3:Bi2O3:SiO2 is 2:2:1:

1.

6. The method for preparing the environmentally friendly medium-high dielectric constant LTCC ceramic material according to claim 4, characterized in that, In steps one and three, the deionized water, ingredients, and balls are added to the ball milling container at a ratio of 1.5:1:3, and the mixture is ball milled at a speed of 250-300 r / min for 6-12 hours.

7. The method for preparing the environmentally friendly medium-high dielectric constant LTCC ceramic material according to claim 4, characterized in that, In step seven, the temperature is increased at a rate of 2°C / min.

Images