Low-temperature co-fired microwave dielectric ceramic material, preparation method and microwave dielectric device

Abstract

The invention relates to a low-temperature co-fired microwave dielectric ceramic material, a preparation method and a microwave dielectric device. The low-temperature co-fired microwave dielectric ceramic material comprises a CaSiO3 matrix, a sintering aid, a toughening agent and a reinforcing agent, the sintering aid comprises Li2O and V2O5, the toughening agent comprises CeO2, and the reinforcing agent comprises ZrO2. The sintering aid, the toughening agent and the reinforcing agent are introduced into the CaSiO3 matrix, so that the sintering temperature when the microwave dielectric ceramic material is sintered to obtain a microwave dielectric ceramic sintered body is reduced, the performance of the prepared microwave dielectric ceramic sintered body is improved, and the microwave dielectric ceramic sintered body has a low dielectric constant, a high quality factor and a low frequency temperature coefficient; and high bending strength and high fracture toughness are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave communication, in particular to a microwave dielectric ceramic material, and more particularly to a low-temperature co-fired microwave dielectric ceramic material, a preparation method and a microwave dielectric device. BACKGROUND

[0002] Microwave dielectric ceramic (WMDC) is a new type of functional ceramic widely used as a dielectric material in the field of microwave communication. With the development of high-end microwave components and the aerospace field, communication equipment is continuously developing towards high frequency, and the demand for low-dielectric microwave dielectric materials is increasing, which usually requires a dielectric constant ε r <9, the lower the dielectric constant, the smaller the signal delay, a high quality factor Q x f > 20000 GHz to reduce the energy loss of the system, a resonance frequency temperature coefficient τ f <±20ppm / ℃, to improve the stability of the system, a sintering temperature T < 950℃ to enable co-firing with low-melting-point Ag electrodes to form a low-temperature co-fired microwave dielectric device.

[0003] Low-dielectric microwave dielectric materials include Al2O3, Zn2SiO4, MgO-SiO2, R2BaCuO5 (R is a rare earth or yttrium), CaSiO3, etc. Among them, the CaSiO3 system has the advantages of low dielectric constant and near-zero temperature coefficient, but the sintering temperature of pure-phase CaSiO3 is above 1300℃, which cannot realize co-firing with low-melting-point Ag electrodes, and the quality factor is slightly insufficient.

[0004] CN114349493A discloses a copper ion doped calcium silicate microwave dielectric ceramic and a preparation method thereof. The invention dopes copper ions in the calcium silicate microwave dielectric ceramic, controls the appropriate copper ion doping amount to inhibit the generation of impurities in the calcined powder, obtains pure-phase α-CaSiO3 powder, and further obtains single-phase β-CaSiO3 ceramic through sintering, and widens the sintering temperature range of the ceramic. The sintering temperature is only above 1050℃, which can realize low-temperature co-firing. The obtained copper ion doped calcium silicate microwave dielectric ceramic has high density, excellent microwave dielectric performance, high quality constant and low dielectric constant.

[0005] CN104402419A discloses a low dielectric constant microwave dielectric ceramic with low sintering temperature and a preparation method thereof, the preparation process comprises the following steps: CaCO3, MgO, SiO2, Al2O3 and CoO and other raw materials are proportionally ball milled and mixed, dried and calcined at 1050-1175 DEG C to obtain ceramic powder; the ceramic powder is re-ball milled, then polyvinyl alcohol aqueous solution is added for granulation, molding, glue removal, and sintering at 1125-1250 DEG C. The invention can reduce the sintering temperature of the ceramic to about 1150 DEG C by introducing magnesium, aluminum and cobalt elements into the crystal structure of calcium silicate, which can well meet the process requirements of low temperature co-firing of ceramic materials for chip multilayer devices, and has good industrial application value.

[0006] CN108083791A discloses a preparation method of a low-loss low-temperature co-fired microwave ceramic material, citric acid is complexed with rare earth metal cations, calcium ions and magnesium ions to form organic bonds with high activity, and the unsaturated titanium-oxygen bonds formed after the high molecular chain of butyl titanate is broken also have high activity, the ceramic particles are bonded, and then carbonized to densify the microwave ceramic, so that the sintering forming temperature of the microwave ceramic material is reduced; in the sintering process, the calcium silicate magnesium powder is sintered at 700-800 DEG C, the silicon-oxygen-silicon bond is broken, the mixed phase of CaSiO3 and MgCaSi2O6 is formed, the pores in the ceramic are reduced, the denseness of the sintered body is improved, the microwave ceramic material is difficult to resonate or the resonance frequency is reduced, thereby reducing the energy loss of high-frequency microwaves, and the application prospect is broad.

[0007] Therefore, it is of great significance to provide a CaSiO3 microwave dielectric ceramic with low sintering temperature and excellent microwave dielectric performance and a preparation method thereof. SUMMARY

[0008] In view of the deficiencies of the prior art, the purpose of the present application is to provide a low-temperature co-fired microwave dielectric ceramic material, a preparation method and a microwave dielectric device. By introducing sintering aids, toughening agents and reinforcing agents into the CaSiO3 matrix, the sintering temperature of the microwave dielectric ceramic material is reduced when sintering the microwave dielectric ceramic sintered body, the performance of the prepared microwave dielectric ceramic sintered body is improved, and the microwave dielectric ceramic sintered body has low dielectric constant, high quality factor and low frequency temperature coefficient, and also has high bending strength and high fracture toughness.

[0009] To achieve the purpose of the present application, the following technical solutions are adopted:

[0010] In a first aspect, the present application provides a low-temperature co-fired microwave dielectric ceramic material, which comprises a CaSiO3 matrix, a sintering aid, a toughening agent and a reinforcing agent; the sintering aid comprises Li2O and V2O5, the toughening agent comprises CeO2, and the reinforcing agent comprises ZrO2.

[0011] In the low-temperature co-fired microwave dielectric ceramic material provided by the present application, Li2O and V2O5 are introduced as the sintering aid, Li2O acts as a low-melting-point substance to promote the transmission and diffusion of substances in the material system, thereby realizing low-temperature sintering, V2O5 acts as a low-melting-point substance to reduce the sintering temperature and also has the effect of refining the grains, which is conducive to improving the bending strength and fracture toughness; CeO2 acts as a toughening agent and exists in the grain boundary to play the role of fine-grain strengthening; the addition of ZrO2 helps to improve the strength of the ceramic sintered body.

[0012] The microwave dielectric ceramic sintered body obtained by sintering the microwave dielectric ceramic material provided by the present application has low dielectric constant, high quality factor and low frequency temperature coefficient, and also has high bending strength and high fracture toughness.

[0013] Preferably, the crystal phase of the CaSiO3 matrix is monoclinic CaSiO3.

[0014] Preferably, in the low-temperature co-fired microwave dielectric ceramic material, the addition amount of Li2O is 0.5% to 2% of the mass of the CaSiO3 matrix, the addition amount of V2O5 is 0.1% to 1% of the mass of the CaSiO3 matrix, the addition amount of CeO2 is 0.5% to 3% of the mass of the CaSiO3 matrix, preferably 1% to 2%, and the addition amount of ZrO2 is 0.1% to 0.5% of the mass of the CaSiO3 matrix.

[0015] In a second aspect, the present application provides a preparation method of the low-temperature co-fired microwave dielectric ceramic material according to the first aspect, which comprises:

[0016] According to the stoichiometric ratio of CaSiO3, CaCO3 and SiO2 are mixed, first wet ball milling is performed, pre-sintering is performed, and a first powder is obtained; the first powder, the sintering aid, the toughening agent and the reinforcing agent are mixed according to the proportions, second wet ball milling is performed, and the low-temperature co-fired microwave dielectric ceramic material is obtained.

[0017] Preferably, the temperature of the pre-sintering is 950°C to 1050°C.

[0018] Preferably, the time of the pre-sintering is 2h to 6h.

[0019] Preferably, the time of each of the first wet ball milling and the second wet ball milling is independently 4h to 8h.

[0020] Preferably, the ball milling medium of the first wet ball milling and the second wet ball milling each independently comprises water and / or ethanol.

[0021] Preferably, the D50 particle size of the second powder after the second wet ball milling is below 1 μm.

[0022] Preferably, the preparation method further comprises mixing the low-temperature co-fired microwave dielectric ceramic material with a binder, granulating, press forming, sintering to obtain a low-temperature co-fired microwave dielectric ceramic sintered body.

[0023] Preferably, the sintering temperature is 850℃~950℃.

[0024] Preferably, the sintering time is 1h~2h.

[0025] Preferably, the binder comprises any one or a combination of at least two of polyvinyl butyral, polymethyl methacrylate or polyvinyl alcohol.

[0026] In a third aspect, the present application provides a microwave dielectric device, the material of the microwave dielectric device comprising the low-temperature co-fired microwave dielectric ceramic material according to the first aspect, or comprising the low-temperature co-fired microwave dielectric ceramic material prepared by the preparation method according to the second aspect.

[0027] The microwave dielectric device provided by the present application is applied to the field of microwave communication, and specifically comprises a laminated dielectric resonator, a microwave antenna, a filter or a coupler.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] By introducing a sintering aid, a toughening agent and a reinforcing agent into the CaSiO3 matrix, the present application reduces the sintering temperature of the microwave dielectric ceramic material to 850℃~950℃ when sintering the microwave dielectric ceramic material to obtain a microwave dielectric ceramic sintered body, and improves the performance of the prepared microwave dielectric ceramic sintered body, so that the microwave dielectric ceramic sintered body has low dielectric constant, high quality factor and low frequency temperature coefficient, and also has high bending strength and high fracture toughness. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is an XRD pattern of the low-temperature co-fired microwave dielectric ceramic material provided in Example 1.

[0031] Figure 2 is an SEM image of the low-temperature co-fired microwave dielectric ceramic material provided in Example 1.

[0032] Figure 3 is a slice morphology image of the microwave dielectric device prepared from the low-temperature co-fired microwave dielectric ceramic material provided in Example 1. DETAILED DESCRIPTION

[0033] The technical solutions of the present application will be further illustrated by the specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application, and should not be regarded as specific limitation to the present application.

[0034] The "range" disclosed in the present application can be defined in the form of lower limit and upper limit, a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of the specific range. The range defined in this way can be inclusive or exclusive of the end values, either end value can be independently included or excluded, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if the ranges of 60~120 and 80~110 are listed for a specific parameter, it is understood that the ranges of 60~110 and 80~120 are also anticipated. In addition, if the minimum range values of 1 and 2 are listed, and if the maximum range values of 3, 4 and 5 are also listed, the following ranges are all anticipated: 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5. In the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand notation for any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between "0-5" have been listed herein, and "0~5" is only a shorthand notation for these numerical combinations. In addition, when it is stated that a parameter is an integer ≥2, it is equivalent to listing the parameter as, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when it is stated that a parameter is an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9 and 10.

[0035] In the present application, "combination of at least two" means, unless otherwise specified, greater than or equal to 2 in number. For example, "any one or a combination of at least two" means one or greater than or equal to two. It can be understood that when referring to "combination of at least two", it refers to the combination of any suitable number of items, that is, the combination of "at least two" items in a way that is not conflicting and can implement the present application.

[0036] If not specifically stated, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0037] The term "embodiment" mentioned in the present application means that the specific features, structures or properties described in connection with the embodiment can be included in at least one embodiment or implementation of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0038] Those skilled in the art can understand that in the method of each embodiment, the writing order of each step does not mean a strict execution order, and the detailed execution order of each step should be determined by its function and possible inherent logic. If not specifically stated, all steps of the present application can be performed sequentially or randomly, and can be preferably performed sequentially. For example, the method comprises step (a) and step (b), which means that the method can comprise sequentially performed steps (a) and (b), or sequentially performed steps (b) and (a). For example, the method can also comprise step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0039] In the present application, the open technical features or technical solutions described by the words such as "include" do not exclude additional members other than the listed members, and can be regarded as providing both the closed features or technical solutions composed of the listed members and the open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2 and a3, and unless otherwise specified, it can also include other members, or it can not include additional members, which can be regarded as providing the technical features or technical solutions of "A is composed of a1, a2 and a3" or "A is selected from a1, a2 and a3", and also providing the technical features or technical solutions of "A includes a1, a2 and a3, and also includes other members".

[0040] In the present application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more related listed items, and also include any and all combinations of the related listed items, including any combination of two related listed items, any combination of more related listed items, or a combination of all related listed items. For example, "A and / or B" indicates a group consisting of A, B and a combination of A and B. Wherein, "including A and / or B" can mean "including A, including B, and including A and B", and can also mean "including A, including B, or including A and B", which can be understood appropriately according to the sentence.

[0041] In the present application, the terms "first", "second", "third", "fourth" and the like in the "first aspect", "second aspect", "third aspect", "fourth aspect" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or quantity, nor can it be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth" and the like only serve the purpose of non-exhaustive enumeration description, and should be understood as not constituting a closed limitation on the quantity.

[0042] In the present application, "optional" means optional, that is, selected from either of the two parallel schemes of "yes" or "no". If there are multiple "optional" in a technical solution, unless otherwise specified, and there is no contradiction or mutual restriction relationship, each "optional" is independent of each other.

[0043] In the present application, unless otherwise specified, it is assumed to be carried out at room temperature or a temperature conventionally set in the art, wherein "room temperature" generally refers to 4℃-35℃, which can refer to 20℃±5℃. In some embodiments of the present application, room temperature refers to 20℃-30℃.

[0044] In one specific embodiment, the present application provides a low-temperature co-fired microwave dielectric ceramic material, which comprises a CaSiO3 matrix, a sintering aid, a toughening agent and a reinforcing agent; the sintering aid comprises Li2O and V2O5, the toughening agent comprises CeO2, and the reinforcing agent comprises ZrO2.

[0045] In the low-temperature co-fired microwave dielectric ceramic material provided by the present application, Li2O and V2O5 are introduced as sintering aids. Li2O acts as a low-melting-point substance to play a role in liquid-phase sintering in the material system, promoting the transmission and diffusion of substances, thereby achieving low-temperature sintering. V2O5, as a low-melting-point substance, not only reduces the sintering temperature, but also has the effect of refining the grain, which is beneficial to improving the bending strength and fracture toughness. CeO2, as a toughening agent, exists in the grain boundary and plays a role in fine-grain strengthening. Doping ZrO2 helps to improve the strength of the ceramic material.

[0046] The microwave dielectric ceramic sintered body obtained by sintering the microwave dielectric ceramic material provided by the present application has low dielectric constant, high quality factor and low frequency temperature coefficient, and also has high bending strength and high fracture toughness.

[0047] In some embodiments, the crystal phase of the CaSiO3 matrix is monoclinic CaSiO3.

[0048] The application regulates the comprehensive performance of the low-temperature co-fired microwave dielectric ceramic material by regulating the adding amount of sintering aids, toughening agents and reinforcing agents in the low-temperature co-fired microwave dielectric ceramic material, wherein Li2O and V2O5 can reduce the sintering temperature, but excessive addition of Li2O will lead to an increase in dielectric loss, and excessive addition of V2O5 will induce adverse reactions, too many impurities, destroy the uniformity of the material structure, and deteriorate the dielectric performance; CeO2 can play a role in fine-grain strengthening, increase the fracture toughness of the ceramic sintered body, but excessive addition will lead to deterioration of the dielectric performance; ZrO2 can improve the strength of the ceramic sintered body, but excessive addition will lead to a decrease in fracture toughness.

[0049] In some embodiments, the adding amount of Li2O in the low-temperature co-fired microwave dielectric ceramic material is 0.5% to 2% of the mass of the CaSiO3 matrix, for example, it can be 0.5%, 0.75%, 1%, 1.25%, 1.5%, 1.75% or 2%, the adding amount of V2O5 is 0.1% to 1% of the mass of the CaSiO3 matrix, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, the adding amount of CeO2 is 0.5% to 3% of the mass of the CaSiO3 matrix, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5% or 3%, preferably 1% to 2%, and the adding amount of ZrO2 is 0.1% to 0.5% of the mass of the CaSiO3 matrix, for example, it can be 0.1%, 0.2%, 0.3%, 0.4% or 0.5%.

[0050] In another specific embodiment, the application provides a preparation method of the low-temperature co-fired microwave dielectric ceramic material as described in the foregoing specific embodiment, and the preparation method comprises:

[0051] According to the stoichiometric ratio of CaSiO3, CaCO3 and SiO2 are mixed, first wet ball milling is performed, pre-sintering is performed, and a first powder is obtained; the first powder, sintering aids, toughening agents and reinforcing agents are mixed according to the ratio, second wet ball milling is performed, and the low-temperature co-fired microwave dielectric ceramic material is obtained.

[0052] In some embodiments, the pre-sintering temperature is 950°C to 1050°C, for example, it can be 950°C, 970°C, 990°C, 1000°C or 1050°C.

[0053] In some embodiments, the pre-sintering time is 2h to 6h, for example, it can be 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h.

[0054] In some embodiments, the first wet ball milling and the second wet ball milling each independently has a time of 4h-8h, for example, can be 4h, 5h, 6h, 7h or 8h.

[0055] In some embodiments, the ball milling medium of the first wet ball milling and the second wet ball milling each independently comprises water and / or ethanol.

[0056] In some embodiments, after the second wet ball milling, the D50 particle size of the second powder is below 1μm, for example, can be 1μm, 0.9μm, 0.8μm, 0.7μm, 0.6μm or 0.6μm.

[0057] The preparation method further comprises mixing the low-temperature co-fired microwave dielectric ceramic material with a binder, granulating, press forming, sintering to obtain a low-temperature co-fired microwave dielectric ceramic sintered body.

[0058] In some embodiments, the sintering temperature is 850℃-950℃, for example, can be 850℃, 860℃, 870℃, 880℃, 890℃, 900℃, 910℃, 920℃, 930℃, 940℃ or 950℃.

[0059] In some embodiments, the sintering time is 1h-2h, for example, can be 1h, 1.2h, 1.4h, 1.6h, 1.8h or 2h.

[0060] In some embodiments, the binder comprises any one or a combination of at least two of polyvinyl butyral, polymethyl methacrylate or polyvinyl alcohol.

[0061] In yet another specific embodiment, the present application provides a microwave dielectric device, the material of which comprises the low-temperature co-fired microwave dielectric ceramic material as described in the aforementioned one specific embodiment, or comprises the low-temperature co-fired microwave dielectric ceramic material prepared by the preparation method as described in the aforementioned another specific embodiment.

[0062] The microwave dielectric device provided by the present application is applied to the field of microwave communication, and specifically comprises a laminated dielectric resonator, a microwave antenna, a filter or a coupler.

[0063] The low-temperature co-fired microwave dielectric ceramic material provided by the present application is prepared by adding a solvent, a binder, a dispersing agent and a plasticizer for slurry preparation, using a casting process to obtain a green sheet, and then performing processes of opening, printing, laminating, cutting, degreasing, sintering, chamfering, silver dipping, silver firing and electroplating to obtain a low-temperature co-fired microwave dielectric device.

[0064] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0065] Examples 1 to 11

[0066] The low-temperature co-fired microwave dielectric ceramic materials provided in Examples 1 to 11 of the present invention all include a monoclinic CaSiO3 matrix, Li2O, V2O5, CeO2 and ZrO2. The weight proportions of each component in the low-temperature co-fired microwave dielectric ceramic materials provided in each example are shown in Table 1.

[0067] The preparation methods of the low-temperature co-fired microwave dielectric ceramic materials provided in Examples 1 to 11 include:

[0068] According to the stoichiometric ratio of CaSiO3, CaCO3 and SiO2 are mixed, and the mixture is first wet ball milled for 6 hours and pre-fired to obtain the first powder. According to the ratio, the first powder is mixed with Li2O, V2O5, CeO2 and ZrO2, and then wet ball milled to obtain a low-temperature co-fired microwave dielectric ceramic material with a D50 particle size of less than 1μm.

[0069] The pre-firing temperature and time, and the sintering temperature and time in Examples 1 to 11 are shown in Table 1.

[0070] Comparative Examples 1 to 4

[0071] The differences between the composition, pre-firing temperature and time, and sintering temperature and time of the microwave dielectric ceramic materials provided in Comparative Examples 1 to 4 and those in Examples 1 to 9 are shown in Table 1.

[0072] Table 1

[0073]

[0074] Performance testing:

[0075] The XRD pattern of the low-temperature co-fired microwave dielectric ceramic material provided in Example 1 is as follows: Figure 1 As shown, its crystal phase is monoclinic CaSiO3 (corresponding to PDF#27-0088).

[0076] The low-temperature co-fired microwave dielectric ceramic materials provided in all the above embodiments and comparative examples were mixed with polymethyl methacrylate resin, granulated, and pressed into cylindrical samples with a diameter of φ14mm×5mm and strip samples with a diameter of L45mm×4mm×3mm under a pressure of 200MPa. The samples were then sintered to obtain cylindrical low-temperature co-fired microwave dielectric ceramic sintered bodies and strip low-temperature co-fired microwave dielectric ceramic sintered bodies, respectively.

[0077] The microwave dielectric properties of the sintered body of the low-temperature co-fired microwave dielectric ceramic material provided in Example 1 were tested by using a TE01δ mode dielectric resonator, including self-resonant frequency (SRF), dielectric constant (ε r ), loss tangent (tan δ), quality factor (Qxf) and frequency temperature coefficient (τ f ).

[0078] The bending strength of the sintered body of the low-temperature co-fired microwave dielectric ceramic material provided in Example 1 was tested by using a three-point bending method, and the single-edge notched beam method was used to process and test the fracture toughness of the L45mmx4mmx3mm long strip sample, and the test results are shown in Table 2.

[0079] The SEM image of the sintered body of the low-temperature co-fired microwave dielectric ceramic material provided in Example 1 is shown in Figure 2 , and the grain growth in the sintered body is small and dense.

[0080] The low-temperature co-fired microwave dielectric device was prepared by mixing the low-temperature co-fired microwave dielectric ceramic material provided in Example 1 with anhydrous ethanol, methacrylic acid resin, butyl benzyl phthalate, ethyl acetate and triolein, and the cast slurry was placed in a ball mill tank and ball milled at a speed of 120 rpm for 8 hours. After vacuum degassing, the cast slurry was formed into a green sheet by a controllable thickness casting machine. The green sheet was then subjected to processes such as opening, printing, lamination, cutting, degassing, sintering, chamfering, silver dipping, silver firing and electroplating to obtain a low-temperature co-fired microwave dielectric device. The cross-sectional morphology of the microwave dielectric device is shown in Figure 3 , and it can be seen that the prepared microwave dielectric device magnet is dense and co-fired well.

[0081] Table 2

[0082]

[0083] In summary, according to the test results of Examples 1 to 6 in Table 2, by introducing sintering aids, toughening agents and reinforcing agents into the CaSiO3 matrix, the sintering temperature of the microwave dielectric ceramic material is reduced to 850-950℃, and its performance is improved, so that it has low dielectric constant (ε r =7.0±0.5), low loss (tan δ<5.5x10 -4 ), high quality factor (Qxf>20000GHz) and low frequency temperature coefficient (τ f <±20ppm / ℃), and also has high bending strength (>160MPa) and high fracture toughness (>2.0MPa·m 1 / 2 ).

[0084] According to the test results of Example 1 and Example 7 and Example 8, if the sintering temperature is too low, the porcelain cannot be sintered, a low-temperature co-fired microwave dielectric ceramic sintered body is obtained, and the microwave dielectric performance is poor; if the sintering temperature is too high, the material is over-sintered, the dielectric performance and the bending strength are deteriorated.

[0085] According to the test results of Example 1 and Example 9 to Example 12, and Comparative Example 1 to Comparative Example 4, if any of Li2O, V2O5, CeO2 and ZrO2 is added in excess or not added, the dielectric performance or the mechanical performance of the prepared ceramic material is deteriorated, and a low-temperature co-fired microwave dielectric ceramic material with good comprehensive performance cannot be prepared.

[0086] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and it should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A low-temperature co-fired microwave dielectric ceramic material, characterized in that, The low-temperature co-fired microwave dielectric ceramic material includes a CaSiO3 matrix, sintering aids, toughening agents, and reinforcing agents; The sintering aids include Li2O and V2O5, the toughening agent includes CeO2, and the reinforcing agent includes ZrO2.

2. The low-temperature co-fired microwave dielectric ceramic material as described in claim 1, characterized in that, The crystal phase of the CaSiO3 matrix is ​​monoclinic CaSiO3.

3. The low-temperature co-fired microwave dielectric ceramic material as described in claim 1, characterized in that, In the aforementioned low-temperature co-fired microwave dielectric ceramic material, the amount of Li2O added is 0.5%~2% of the mass of the CaSiO3 matrix, the amount of V2O5 added is 0.1%~1% of the mass of the CaSiO3 matrix, the amount of CeO2 added is 0.5%~3% of the mass of the CaSiO3 matrix, and the amount of ZrO2 added is 0.1%~0.5% of the mass of the CaSiO3 matrix.

4. A method for preparing a low-temperature co-fired microwave dielectric ceramic material as described in any one of claims 1 to 3, characterized in that, The preparation method includes: According to the stoichiometric ratio of CaSiO3, CaCO3 and SiO2 are mixed, subjected to a first wet ball milling, and pre-calcined to obtain a first powder; according to the formula, the first powder is mixed with sintering aid, toughening agent and reinforcing agent, and subjected to a second wet ball milling to obtain the low-temperature co-fired microwave dielectric ceramic material.

5. The preparation method according to claim 4, characterized in that, The pre-firing temperature is 950℃~1050℃; And / or, the pre-firing time is 2h~6h.

6. The preparation method according to claim 4, characterized in that, The time for the first wet ball milling and the second wet ball milling is independently 4h~8h; And / or, the milling media of the first wet ball mill and the second wet ball mill each independently include water and / or ethanol; And / or, after the second wet ball milling, the D50 particle size of the second powder is below 1 μm.

7. The preparation method according to claim 4, characterized in that, The preparation method further includes mixing the low-temperature co-fired microwave dielectric ceramic material with a binder, granulating, pressing, and sintering to obtain a low-temperature co-fired microwave dielectric ceramic sintered body.

8. The preparation method according to claim 7, characterized in that, The sintering temperature is 850℃~950℃; And / or, the sintering time is 1h to 2h.

9. The preparation method according to claim 7, characterized in that, The adhesive comprises any one or a combination of at least two of polyvinyl butyral, polymethyl methacrylate, or polyvinyl alcohol.

10. A microwave dielectric device, wherein the material of the microwave dielectric device comprises the low-temperature co-fired microwave dielectric ceramic material as described in any one of claims 1 to 3, or comprises the low-temperature co-fired microwave dielectric ceramic material prepared by the preparation method described in any one of claims 4 to 9.

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