Microwave dielectric ceramic materials and their preparation methods and applications

Abstract

The present application belongs to the field of ceramic technology, and in particular relates to a microwave dielectric ceramic material, a preparation method thereof, and an application thereof. The microwave dielectric ceramic material comprises a ceramic solid solution having a chemical formula of xAMoO4‑yLi2MoO4; wherein the A position comprises at least five transition metal elements, the total molar content of the transition metal elements is 100%, 0<x<1, 0<y<1, and x+y=1. Through the combined action of the components in the ceramic solid solution, the sintering temperature of the microwave dielectric ceramic material is reduced to below 700°C, and the material has microwave dielectric properties such as a higher relative dielectric constant and quality factor, and a lower temperature drift coefficient, thereby improving the transmission efficiency of microwave communications, reducing signal loss, and reducing interference. The material can more effectively store and release energy, and the ceramic material is less affected by temperature changes, thereby improving the stability of microwave dielectric properties and service life.

Description

Technical Field

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

[0002] With the large-scale commercialization of 5G mobile communication technology, the requirements for devices and materials such as microwave substrates, dielectric resonators, and filters have been greatly increased, and low dielectric constant microwave ceramics have received increasing attention. Low-temperature co-fired ceramic (LTCC) technology helps to achieve the miniaturization, integration, and modularization of communication devices, becoming the first choice for the preparation of new generation electronic devices. In order to realize the application of LTCC technology, dielectric ceramic materials need to meet the following requirements: low dielectric constant ε r And the lower sintering temperature (<900℃) enables LTCC technology to be co-fired with Ag. r High Q value can reduce the signal propagation delay time, while high Q value and low loss can help expand the operating frequency bandwidth of the device, enhance the frequency selection characteristics and suppress signal attenuation.

[0003] Currently, high entropy (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Li 0.4 ) Al2O4 ceramics exhibit good microwave dielectric properties after sintering at 1550℃ for 4h: ε r is 7.4, the Q×f value reaches 58000GHz, and the resonant frequency temperature coefficient τ f is -51ppm / ℃. However, (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Li 0.4 ) The sintering temperature of Al2O4 ceramics is as high as 1550℃, while in the LTCC process, the temperature of ceramics and silver electrodes cannot be higher than 800℃. 0.2 Co 0.2 Zn 0.2 Ni 0.2 Li 0.4 )The higher sintering temperature of Al2O4 ceramics cannot meet the requirements of co-firing with electrodes in LTCC technology, limiting their application scenarios in the field of millimeter wave communications. Summary of the Invention

[0004] The purpose of this application is to provide a microwave dielectric ceramic material and its preparation method and application, in order to solve the existing (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Li0.4 ) The sintering temperature of high-entropy ceramics such as Al2O4 is too high to meet the problem of co-firing with electrodes in LTCC technology.

[0005] To achieve the above application objectives, the technical solutions adopted in this application are as follows:

[0006] In a first aspect, the present application provides a microwave dielectric ceramic material, which includes a ceramic solid solution with a chemical expression of xAMoO4-yLi2MoO4; wherein the A position includes at least five transition metal elements, the total molar content of the transition metal elements is 100%, 0<x<1, 0<y<1, and x+y=1.

[0007] In some embodiments, the transition metal elements include at least five of Mg, Co, Zn, Ni, Mn, Cu, Fe, and Cr.

[0008] In some embodiments, the A site includes five transition metal elements in equal molar ratios.

[0009] In some embodiments, the chemical formula of the ceramic solid solution is x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4-yLi2MoO4.

[0010] In some embodiments, in the ceramic solid solution of xAMoO4-yLi2MoO4, 0.88≤x<1, 0<y≤0.12.

[0011] In some embodiments, x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )In the ceramic solid solution of MoO4-yLi2MoO4, 0.88≤x<1, 0<y≤0.12.

[0012] In a second aspect, the present application provides a method for preparing a microwave dielectric ceramic material, comprising the following steps:

[0013] The raw material components are obtained according to the stoichiometric ratio of each element in the ceramic solid solution of the chemical formula xAMoO4-yLi2MoO4; wherein the A position includes at least five transition metal elements, the total molar content of the transition metal elements is 100%, 0<x<1, 0<y<1, and x+y=1;

[0014] sintering AMoO4 synthetic blocks and Li2MoO4 synthetic blocks respectively;

[0015] The AMoO4 synthetic block and the Li2MoO4 synthetic block are crushed, a dispersant is added to prepare a mixed powder, and a binder is added to mix and granulate to obtain a granulated powder;

[0016] The granulated powder is made into a ceramic green body, which is subjected to debinding treatment and sintering treatment in sequence to form the ceramic solid solution of xAMoO4-yLi2MoO4, thereby obtaining a microwave dielectric ceramic material.

[0017] In some embodiments, the step of firing the AMoO4 synthetic block includes: ball milling the A source and the molybdenum source for 2 to 6 hours at a mass ratio of material, ball and water of 1: (1 to 3): (1 to 2), drying and sieving, and sintering at a temperature of 800 to 900°C for 2 to 4 hours to obtain the AMoO4 synthetic block.

[0018] In some embodiments, the step of firing the Li2MoO4 synthetic block includes: ball milling the lithium source and the molybdenum source for 2 to 6 hours at a mass ratio of material, ball and water of 1: (1 to 3): (1 to 2), drying and sieving, and sintering at a temperature of 500 to 600°C for 2 to 4 hours to obtain the Li2MoO4 synthetic block.

[0019] In some embodiments, the preparation of the mixed powder includes the steps of: grinding the AMoO4 synthetic block and the Li2MoO4 synthetic block into powders respectively and then mixing them, and ball milling them to a particle size D50 not higher than 0.8 μm under the condition that the mass ratio of material, ball and water is 1:(1~3):(1~2).

[0020] In some embodiments, the mixing granulation method adopts spray granulation.

[0021] In some embodiments, the preparation of the ceramic green body comprises the steps of: adding the granulated powder into a mold, and dry pressing the mold under a pressure of 80 to 200 MPa to obtain the ceramic green body.

[0022] In some embodiments, the debinding treatment comprises: maintaining the temperature at 400-500° C. for 2-3 hours.

[0023] In some embodiments, the sintering treatment conditions include: heating to 600-700° C. at a rate of 1-10° C. / min and maintaining the temperature for 2-4 hours.

[0024] In some embodiments, the A source includes a magnesium source, a cobalt source, a zinc source, a nickel source, and a manganese source.

[0025] In some embodiments, the dispersant includes at least one of polyacrylamide, polycarboxylic acid amino salt, ammonium salt, and quaternary ammonium salt.

[0026] In some embodiments, the binder includes at least one of polyvinyl alcohol, polyvinyl butyral, and polyethylene glycol.

[0027] In some embodiments, the mass ratio of the dispersant to the mixed powder is (0.2-0.4):100.

[0028] In some embodiments, the mass ratio of the binder to the mixed powder is (2-4):100.

[0029] In some embodiments, the raw material components include at least one of metal oxides, metal hydroxides, and metal salts.

[0030] In some embodiments, the microwave dielectric ceramic material comprises a chemical formula of x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4-yLi2MoO4 ceramic solid solution, 0.88≤x<1, 0<y≤0.12.

[0031] In a third aspect, the present application provides a microwave dielectric ceramic device, wherein the raw material components for preparing the microwave dielectric ceramic device include the above-mentioned microwave dielectric ceramic material or the microwave dielectric ceramic material prepared by the above-mentioned method for preparing the microwave dielectric ceramic material.

[0032] The microwave dielectric ceramic material provided in the first aspect of the present application includes a ceramic solid solution having the chemical formula xAMoO4-yLi2MoO4, wherein AMoO4 in the ceramic solid solution is a microwave ceramic with a high-entropy spinel structure (ABO4), wherein B is Mo ions, and the A-site is composed of a solid solution of five or more transition metal elements, each of which is in an equiatomic ratio or a near-equiatomic ratio. The transition metal atoms are randomly distributed in the lattice, and the radii and chemical bonds of different metal atoms vary greatly. The position and surrounding environment of each atom are different, resulting in greater lattice distortion and defects within the lattice. Not only does the higher configurational entropy facilitate the formation of a single phase, but the A-site metal elements and their ratios can also regulate the sintering temperature of the microwave dielectric ceramic material, thereby reducing the sintering temperature while ensuring the dielectric properties of the microwave dielectric ceramic material. In addition, Li2MoO4, as a liquid phase additive in microwave dielectric ceramic materials, has excellent microwave dielectric properties and is suitable for the LTCC field. When co-sintered with AMoO4 to form a solid solution, Li ions will enter the A site in the AMoO4 crystal structure to form a new compound, which can significantly reduce the sintering temperature of the ceramic.

[0033] The second aspect of the present application relates to a method for preparing a microwave dielectric ceramic material. The raw material components are obtained according to the stoichiometric ratios of the elements of a ceramic solid solution having the chemical formula xAMoO4-yLi2MoO4; an AMoO4 synthetic block and a Li2MoO4 synthetic block are fired separately based on the different synthesis temperatures of the AMoO4 high-entropy structural ceramic and Li2MoO4; the two synthetic blocks are crushed into powder, a dispersant is added to assist in grinding to form a mixed powder, and then a binder is added for mixed granulation. After the granulated powder is made into a ceramic green body, a binder removal treatment is performed to burn and decompose organic matter to remove organic matter in the body, and then a sintering treatment is performed to form a ceramic solid solution of xAMoO4-yLi2MoO4, i.e., a microwave dielectric ceramic material. The preparation process is simple, making it suitable for large-scale industrial production and application. The resulting microwave dielectric ceramic material, through the combined action of the components in the xAMoO4-yLi2MoO4 ceramic solid solution, reduces the sintering temperature to below 700°C. It also exhibits excellent microwave dielectric properties, with a high relative permittivity and quality factor (Q×f). This improves microwave communication transmission efficiency, reduces signal loss, mitigates interference, and allows for more efficient energy storage and release, resulting in better filtering and lower losses. Furthermore, it exhibits a relatively low temperature drift coefficient, indicating that parameters such as frequency and resistance of the microwave dielectric ceramic material are less affected by temperature changes, resulting in excellent performance and service life stability.

[0034] The raw material components for preparing microwave dielectric ceramic devices in the third aspect of the present application include the above-mentioned microwave dielectric ceramic material. The microwave dielectric ceramic material has a low sintering temperature and is suitable for co-firing with Ag electrodes in the LTCC process. It also has good microwave dielectric properties such as a high relative dielectric constant and quality factor Q×f, a low temperature drift coefficient, etc. Therefore, it is beneficial to improve the energy and signal transmission effect of microwave dielectric ceramic devices, reduce losses, and increase the service life of the devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 1 is a flow chart of a method for preparing a microwave dielectric ceramic material provided in an embodiment of the present application;

[0037] Figure 2 The parallel plate resonance method provided in the embodiment of the present application is used to test the relative dielectric constant ε r Schematic diagram of the structure;

[0038] Figure 3 It is a structural diagram of the closed-cavity method for testing the quality factor Q×f provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0040] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0041] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple.

[0042] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0043] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0044] The weights of the relevant components mentioned in the examples of this specification may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components in the examples of this specification is proportionally enlarged or reduced according to the examples of this specification, it is within the scope disclosed in the examples of this specification. Specifically, the mass described in the examples of this specification may be μg, mg, g, kg, etc., which are mass units commonly known in the chemical industry.

[0045] The terms "first" and "second" are used solely for descriptive purposes to distinguish objects, such as substances, from one another and should not be understood to indicate or imply relative importance or to implicitly specify the quantity of the technical features being referred to. For example, without departing from the scope of the embodiments of this application, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0046] A first aspect of an embodiment of the present application provides a microwave dielectric ceramic material, which includes a ceramic solid solution with a chemical expression of xAMoO4-yLi2MoO4; wherein the A position includes at least five transition metal elements, the total molar content of the transition metal elements is 100%, 0<x<1, 0<y<1, and x+y=1.

[0047] The microwave dielectric ceramic material provided in the first aspect of the embodiment of the present application includes a ceramic solid solution with the chemical formula xAMoO4-yLi2MoO4, in which AMoO4 is a microwave ceramic with a high-entropy spinel structure (ABO4), wherein B is Mo ions, and the A position is composed of five or more transition metal elements forming a solid solution, each transition metal element is in an equiatomic ratio or a near-equiatomic ratio, and each transition metal atom is randomly distributed in the lattice. The radius and chemical bond of different metal atoms vary greatly, and the position and surrounding environment of each atom are different, resulting in greater lattice distortion and defects within the lattice. Not only does a higher configurational entropy facilitate the formation of a single phase, but the metal elements and their ratios at the A position can also regulate the sintering temperature of the microwave dielectric ceramic material, thereby reducing the sintering temperature while ensuring the dielectric properties of the microwave dielectric ceramic material. In addition, Li2MoO4, as a liquid phase additive in microwave dielectric ceramic materials, has excellent microwave dielectric properties and is suitable for the LTCC field. It is close to the physical phase, structure, and sintering temperature of AMoO4. By co-sintering to form a solid solution, Li ions will enter the A position in the AMoO4 crystal structure to form a new compound, which can significantly reduce the sintering temperature of the ceramic.

[0048] The microwave dielectric ceramic material of the embodiment of the present application reduces the sintering temperature of the microwave dielectric ceramic material to below 700°C through the joint action of the various components in the xAMoO4-yLi2MoO4 ceramic solid solution, and has good microwave dielectric properties, a high relative dielectric constant and quality factor Q×f, which improves the transmission efficiency of microwave communication, reduces signal loss, reduces interference, stores and releases energy more effectively, and has better filtering effect and lower loss. At the same time, it has a relatively low temperature drift coefficient, which means that the parameters such as frequency or resistance of the microwave dielectric ceramic material are less affected by temperature changes, and its performance and service life are stable. Therefore, the microwave dielectric ceramic material of the embodiment of the present application can be used in the LTCC process and co-fired with Ag electrodes, and can be better used in the preparation of communication devices such as small-size filters, high-speed substrates for millimeter waves, dielectric waveguides, and Monoblock filters in Wifi 6E devices.

[0049] In some possible implementations, the transition metal elements include at least five of Mg, Co, Zn, Ni, Mn, Cu, Fe, and Cr; these transition metal elements have different metal atomic radii and large differences in chemical bond phases, and are randomly distributed in the lattice lattice. The position of each atom and the surrounding environment are different, resulting in greater lattice distortion and defects inside the lattice. Higher configurational entropy is conducive to the formation of a single phase, and is more conducive to reducing the sintering temperature of microwave dielectric ceramics.

[0050] In some possible implementations, the A-site includes five transition metal elements in equal molar ratios. The ratio of different transition metal elements in the A-site of the AMoO4 embodiment of the present application has a certain influence on the sintering temperature of the high-entropy ceramic. When the elements are in equal molar ratios, it is more conducive to lowering the sintering temperature of the microwave dielectric ceramic material, and the required sintering temperature is the lowest in this case.

[0051] In some possible implementations, the chemical expression of the ceramic solid solution is x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4-yLi2MoO4; 0<x<1, 0<y<1, and x+y=1. In this case, the five transition metals are randomly distributed in the A-site lattice in equal molar ratios. Through the combined action of these five specific transition metal atoms with different metal atomic radii and different chemical bonds, greater lattice distortion and defects are generated within the lattice, which is more conducive to the construction of single-phase high-entropy ceramics and can effectively reduce the sintering temperature of microwave dielectric ceramic materials.

[0052] In some possible implementations, in the ceramic solid solution of xAMoO4-yLi2MoO4, 0.88≤x<1, 0<y≤0.12. In the microwave dielectric ceramic material of the embodiment of the present application, Li2MoO4, as a liquid-phase additive, can reduce the sintering temperature of the microwave dielectric ceramic. In the xAMoO4-yLi2MoO4 ceramic solid solution, lithium ions themselves occupy the A site, and excessive doping levels will, to a certain extent, destroy the original high-entropy structure. This ratio range of 0.88≤x<1, 0<y≤0.12 is beneficial for both reducing the sintering temperature of the microwave dielectric ceramic material and ensuring the dielectric properties of the microwave dielectric ceramic material.

[0053] In some possible implementations, x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4-yLi2MoO4 ceramic solid solution, 0.88≤x<1, 0<y≤0.12. In this case, the sintering temperature of the microwave dielectric ceramic material is not higher than 700℃, and it has excellent microwave dielectric properties. Its relative dielectric constant ε r The quality factor (Q×f) is as high as 49400~59200GHz, and the resonant frequency temperature coefficient τ f is -52 to -59 ppm / °C. For example, x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )In MoO4-yLi2MoO4, x is 99%, y is 1%, or x is 98%, y is 2%, or x is 96%, y is 4%, or x is 92%, y is 8%, or x is 96%, y is 4%, or x is 90%, y is 10%, or x is 88%, y is 12%, etc.

[0054] The microwave dielectric ceramic material of the above embodiment of the present application can be prepared by the method of the following embodiment.

[0055] In a second aspect, the present invention provides a method for preparing a microwave dielectric ceramic material. Figure 1 As shown, the following steps are included:

[0056] S10. Obtaining raw material components according to the stoichiometric ratio of each element in the ceramic solid solution having the chemical expression xAMoO4-yLi2MoO4; wherein the A position includes at least five transition metal elements, the total molar content of the transition metal elements is 100%, 0<x<1, 0<y<1, and x+y=1;

[0057] S20. AMoO4 and Li2MoO4 synthesized blocks were fired separately;

[0058] S30 AMoO4 synthetic block and Li2MoO4 synthetic block crushed, adding a dispersant to prepare a mixed powder, adding a binder and mixing granulation to obtain a granulated powder;

[0059] S40. The granulated powder is made into a ceramic green body, and the debinding treatment and sintering treatment are performed in sequence to form the ceramic solid solution of xAMoO4-yLi2MoO4 to obtain a microwave dielectric ceramic material.

[0060] The method for preparing a microwave dielectric ceramic material in an embodiment of the present application comprises obtaining raw material components according to the stoichiometric ratios of the elements in a ceramic solid solution having the chemical formula xAMoO4-yLi2MoO4; firing an AMoO4 synthetic block and a Li2MoO4 synthetic block at different sintering temperatures for the AMoO4 high-entropy structural ceramic and Li2MoO4, respectively; crushing the two synthetic blocks into powders, adding a dispersant to aid grinding to form a mixed powder, and then adding a binder for mixed granulation. After the granulated powder is formed into a ceramic green body, a binder removal treatment is performed to burn and decompose organic matter to remove organic matter from the green body, and then a sintering treatment is performed to form a ceramic solid solution of xAMoO4-yLi2MoO4, i.e., a microwave dielectric ceramic material. The preparation process is simple, making it suitable for large-scale industrial production and application. The resulting microwave dielectric ceramic material, through the combined action of the components in the xAMoO4-yLi2MoO4 ceramic solid solution, reduces the sintering temperature to below 700°C. It also exhibits excellent microwave dielectric properties, with a high relative permittivity and quality factor (Q×f). This improves microwave communication transmission efficiency, reduces signal loss, mitigates interference, and allows for more efficient energy storage and release, resulting in better filtering and lower losses. Furthermore, it exhibits a relatively low temperature drift coefficient, indicating that parameters such as frequency and resistance of the microwave dielectric ceramic material are less affected by temperature changes, resulting in excellent performance and service life stability.

[0061] In step S10, the raw material components are obtained according to the stoichiometric ratio of each element in the ceramic solid solution having the chemical expression xAMoO4-yLi2MoO4. The stoichiometric ratio may be the molar ratio of each metal element or the mass of each component calculated based on the molar amount.

[0062] In some possible implementations, the transition metal elements include at least five of Mg, Co, Zn, Ni, Mn, Cu, Fe, and Cr; these transition metal elements have different metal atomic radii and large differences in chemical bond phases, and are randomly distributed in the lattice lattice. The position of each atom and the surrounding environment are different, resulting in greater lattice distortion and defects inside the lattice. Higher configurational entropy is conducive to the formation of a single phase, and is more conducive to reducing the sintering temperature of microwave dielectric ceramics.

[0063] In some possible implementations, five transition metal elements are included in equal molar ratios in position A. When the metal elements are in equal molar ratios, it is more conducive to reducing the sintering temperature of the microwave dielectric ceramic material, and the required sintering temperature is the lowest.

[0064] In some possible implementations, the microwave dielectric ceramic material contains a chemical formula of x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4-yLi2MoO4 ceramic solid solution, 0.88≤x<1, 0<y≤0.12. In this case, the sintering temperature of the microwave dielectric ceramic material is not higher than 700℃, and it has excellent microwave dielectric properties. Its relative dielectric constant ε r The quality factor (Q×f) is as high as 49400~59200GHz, and the resonant frequency temperature coefficient τ f It is -52~-59ppm / ℃.

[0065] In some possible implementations, source A includes a magnesium source, a cobalt source, a zinc source, a nickel source, and a manganese source; in this case, the A site is composed of five metal elements: Mg, Co, Zn, Ni, and Mn. Additionally, the raw material components also include a molybdenum source and a lithium source.

[0066] In some possible implementations, the raw material components include at least one of a metal oxide, a metal hydroxide, and a metal salt. In some embodiments, the manganese source includes at least one of manganese oxide and manganese carbonate; the cobalt source includes at least one of cobalt oxide and cobalt carbonate; the zinc source includes at least one of zinc oxide and zinc carbonate; the nickel source includes at least one of nickel oxide and nickel carbonate; the magnesium source includes at least one of magnesium oxide, magnesium carbonate, basic magnesium carbonate, and magnesium hydroxide; the lithium source includes at least one of lithium carbonate and lithium oxide; and the molybdenum source includes at least one of molybdenum oxide and molybdenum carbonate.

[0067] In the above step S20:

[0068] In some possible implementations, the step of firing the AMoO4 synthetic block includes: ball milling the A source and the molybdenum source for 2 to 6 hours at a mass ratio of material, ball and water of 1: (1 to 3): (1 to 2), fully mixing and grinding the raw material components into a mixed powder, drying and sieving, and sintering at a temperature of 800 to 900°C for 2 to 4 hours to synthesize the AMoO4 synthetic block. Exemplarily, the mass ratio of material, ball and water can be 1:1:1, 1:2:1, 1:3:1, 1:1:2, 1:2:2, 1:3:2, etc., the ball milling time can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, the sintering temperature can be 800°C, 850°C, 900°C, etc., and the sintering time can be 2 hours, 3 hours, 4 hours, etc.

[0069] In some possible implementations, the step of sintering the Li2MoO4 synthetic block includes: ball milling a lithium source and a molybdenum source for 2 to 6 hours at a mass ratio of material, ball, and water of 1:(1 to 3):(1 to 2), fully mixing and grinding the raw material components into a mixed powder, drying and sieving, and sintering at a temperature of 500 to 600°C for 2 to 4 hours to synthesize the Li2MoO4 synthetic block. Exemplarily, the mass ratio of material, ball, and water can be 1:1:1, 1:2:1, 1:3:1, 1:1:2, 1:2:2, 1:3:2, etc., the ball milling time can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, the sintering temperature can be 500°C, 550°C, 600°C, etc., and the sintering time can be 2 hours, 3 hours, 4 hours, etc.

[0070] In the above step S30:

[0071] In some possible implementations, the preparation of the mixed powder includes the steps of grinding AMoO4 synthetic blocks and Li2MoO4 synthetic blocks into powders, mixing the powders, adding a dispersant, and ball milling the mixture to a particle size D50 no greater than 0.8 μm at a mass ratio of material, balls, and water of 1:(1-3):(1-2). The dispersant serves to prevent the ceramic slurry from agglomerating during the ball milling process, allowing for faster grinding. Ball milling to a particle size D50 no greater than 0.8 μm provides a small particle size that facilitates subsequent sintering reactions and improves sintering efficiency. Exemplarily, the mass ratio of material, ball and water can be 1:1:1, 1:2:1, 1:3:1, 1:1:2, 1:2:2, 1:3:2, etc., and the ball milling is performed to a particle size D50 of less than 0.8 μm, or less than 0.7 μm, or less than 0.6 μm, or less than 0.5 μm, or less than 0.4 μm, or less than 0.3 μm, or less than 0.2 microns, or less than 0.1 microns, etc.

[0072] In some possible implementations, the dispersant includes at least one of polyacrylamide, polycarboxylic acid ammonium salt, ammonium salt, and quaternary ammonium salt; these dispersants are beneficial in preventing the ceramic slurry from agglomerating during the ball milling process, thereby allowing the powder to be ground more quickly.

[0073] In some possible implementations, the mass ratio of dispersant to mixed powder is (0.2-0.4):100. At this ratio, the dispersant can sufficiently prevent the ceramic slurry from agglomerating during ball milling, thereby increasing the grinding rate of the powder. It also prevents excessive dispersant content in the granulated powder from affecting the density of subsequent ceramic sintering. For example, the mass ratio of dispersant to mixed powder can be 0.2:100, 0.3:100, 0.4:100, etc.

[0074] In some possible implementations, the mixed granulation method adopts spray granulation; a binder is added to make the powder adhere during the spray granulation process, thereby facilitating molding and granulation.

[0075] In some possible implementations, the binder includes at least one of polyvinyl alcohol (PVA), polyvinyl butyral (PVB), and polyethylene glycol (PEG). These binders can promote powder bonding and molding, and obtain granulated powder with good structural stability through spray granulation.

[0076] In some possible implementations, the mass ratio of binder to mixed powder is (2-4):100. This ratio achieves better granulation results while avoiding excessive binder content in the granulated powder, which could affect the density of the subsequent ceramic sintering. For example, the mass ratio of binder to mixed powder can be 2:100, 3:100, 4:100, etc.

[0077] In the above step S40:

[0078] In some possible implementations, the preparation of a ceramic green body includes the steps of: adding granulated powder to a mold, dry pressing and molding under a pressure of 80 to 200 MPa to obtain a ceramic green body. The greater the pressure, the denser the green body and the higher the density of the ceramic. The pressure range of the ceramic green body is generally 80 to 200 MPa. If the pressure is too high, the equipment needs to provide a greater pressure, which requires higher requirements for the press and mold, and the density improvement gradually loses its meaning and the marginal effect is very low. Exemplary, the pressure can be 80 MPa, 90 MPa, 100 MPa, 110 MPa, 120 MPa, 130 MPa, 140 MPa, 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, etc. In some embodiments, the granulated powder is added to the mold and dry pressed and molded under a pressure of 100 to 150 MPa to obtain a ceramic green body.

[0079] In some possible implementations, the debinding treatment includes holding the ceramic at 400-500°C for 2-3 hours. During this debinding process, organic matter in the ceramic greenware is decomposed and volatilized at high temperatures. Slow debinding reduces the risk of large pores and the impact on the density and strength of the ceramic. For example, the debinding treatment temperature can be 400°C, 450°C, 500°C, etc., and the holding time can be 2 hours, 3 hours, etc.

[0080] In some possible implementations, the sintering process conditions include: heating to 600-700°C at a rate of 1-10°C / min and holding for 2-4 hours. Under these sintering conditions, the lithium ions in Li2MoO4 enter the A site of the AMoO4 crystal structure, forming a xAMoO4-yLi2MoO4 solid solution, forming a new compound, and obtaining a microwave dielectric ceramic material. For example, the sintering process heating rate can be 1°C / min, 2°C / min, 4°C / min, 5°C / min, 6°C / min, 8°C / min, 10°C / min, etc., the holding temperature can be 600°C, 650°C, 700°C, etc., and the holding time can be 2 hours, 3 hours, 4 hours, etc.

[0081] In a third aspect, an embodiment of the present application provides a microwave dielectric ceramic device, wherein the raw material components for preparing the microwave dielectric ceramic device include the above-mentioned microwave dielectric ceramic material or the microwave dielectric ceramic material prepared by the above-mentioned method for preparing the microwave dielectric ceramic material.

[0082] The raw material components for preparing the microwave dielectric ceramic device in the embodiment of the present application include the above-mentioned microwave dielectric ceramic material. The microwave dielectric ceramic material has a low sintering temperature and is suitable for co-firing with Ag electrodes in the LTCC process. It also has good microwave dielectric properties such as a high relative dielectric constant and quality factor Q×f, and a low temperature drift coefficient. Therefore, it is beneficial to improve the energy and signal transmission effect of the microwave dielectric ceramic device, reduce losses, and increase the service life of the device.

[0083] In some embodiments, microwave dielectric ceramic devices include but are not limited to small-size filters in Wifi 6E equipment, high-speed substrates for millimeter waves, dielectric waveguides, Monoblock filters and other communication devices.

[0084] In order to enable those skilled in the art to clearly understand the above implementation details and operations of the present application, and to significantly demonstrate the improved performance of the microwave dielectric ceramic material and the preparation method thereof in the embodiments of the present application, the above technical solution is illustrated by multiple embodiments below.

[0085] Examples 1 to 7

[0086] Examples 1 to 7 provide a microwave dielectric ceramic material, including a chemical formula x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4-yLi2MoO4 ceramic solid solution, wherein the specific values ​​of x and y are shown in Table 1 below;

[0087] Its preparation comprises the steps of:

[0088] ① According to the chemical formula (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4 and Li2MoO4, calculate the mass of each raw material required, the raw materials are analytically pure, and are 99.9wt% MgO, 99.8wt% CoO, 99.9wt% ZnO, 99.8wt% NiO, 99wt% MnCO3, 99.9wt% Li2CO3 and 99.9wt% MoO3 respectively.

[0089] ② 99.9wt% MgO, 99.8wt% CoO, 99.9wt% ZnO, 99.8wt% NiO, 99wt% MnCO3 and 99.9wt% MoO3 raw materials were accurately weighed and poured into a ball mill, and deionized water and ZrO2 grinding balls were added; the weight ratio of the three was: material: ball: deionized water = 1:2:1.5; after ball milling for 4 hours, the slurry was dried at 100°C for 2 hours and sieved to obtain a mixture powder; the mixture powder was placed in an alumina crucible and calcined at 800°C for 2 hours to obtain (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 ) MoO4 synthetic block. 99.9wt% Li2CO3 and 99.9wt% MoO3 raw materials were accurately weighed and poured into a ball mill. Deionized water and ZrO2 grinding balls were added; the weight ratio of the three was: material: balls: deionized water = 1:2:1.5. After ball milling for 4 hours, the slurry was dried at 100°C for 2 hours and sieved to obtain a mixture powder. The mixture powder was placed in an alumina crucible and synthesized at 550°C for 2 hours to obtain Li2MoO4 synthetic block.

[0090] ③ According to the chemical expression x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2)MoO4-yLi2MoO4, the ratio of x and y is calculated to obtain the required (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4 synthetic block and Li2MoO4 synthetic block mass, (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4 synthetic blocks and Li2MoO4 synthetic blocks are placed in a ball mill for secondary ball milling, and deionized water and ZrO2 grinding balls are added; the weight ratio of the three is: material: ball: deionized water = 1:2:1.5; a certain proportion of dispersant 0.3wt% is added to the slurry, and after grinding for 2 hours, it is transferred to a sand mill for further refinement until the powder has a particle size D50 of less than 0.8μm; a certain proportion of PVA polyvinyl alcohol 2wt% and PEG polyethylene glycol 1.5wt% are added to the above slurry for spray granulation to obtain granulated powder.

[0091] ④ The granulated powder was placed in a mold and dry pressed at a pressure of 100 MPa to obtain a green sheet; the green sheet was kept at 500°C for 2 hours to remove organic matter, and then the temperature was increased to 600-700°C at a rate of 5°C / min (the specific sintering temperatures of Examples 1-7 are shown in Table 1 below), and the temperature was kept constant for 4 hours to obtain a sintered body, forming x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4-yLi2MoO4 ceramic solid solution, that is, microwave dielectric ceramic material.

[0092] Comparative Example 1

[0093] A microwave dielectric ceramic material, the chemical formula is (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4;

[0094] Its preparation comprises the steps of:

[0095] ① According to the chemical formula (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2)MoO4, calculate the mass of each raw material required. The raw materials are analytically pure, namely 99.9wt% MgO, 99.8wt% CoO, 99.9wt% ZnO, 99.8wt% NiO, 99wt% MnCO3 and 99.9wt% MoO3.

[0096] ② 99.9wt% MgO, 99.8wt% CoO, 99.9wt% ZnO, 99.8wt% NiO, 99wt% MnCO3 and 99.9wt% MoO3 raw materials were accurately weighed and poured into a ball mill, and deionized water and ZrO2 grinding balls were added; the weight ratio of the three was: material: ball: deionized water = 1:2:1.5; after ball milling for 4 hours, the slurry was dried at 100°C for 2 hours and sieved to obtain a mixture powder; the mixture powder was placed in an alumina crucible and calcined at 800°C for 2 hours to obtain (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4 synthesized bulk.

[0097] ③ Place the synthetic block in a ball mill for secondary ball milling, add deionized water and ZrO2 grinding balls; the weight ratio of the three is: material: balls: deionized water = 1:2:1.5; add a certain proportion of dispersant 0.3wt% to the slurry, grind for 2 hours, and then transfer to a sand mill for further refinement until the powder particle size D50 is less than 0.8μm; add a certain proportion of PVA polyvinyl alcohol 2wt% and PEG polyethylene glycol 1.5wt% to the above slurry for spray granulation to obtain granulated powder.

[0098] ④ Place the granulated powder into a mold and dry-press it at a pressure of 100 MPa to obtain a green sheet; keep the green sheet at 500°C for 2 hours to remove organic matter, then heat it to 900°C at a rate of 5°C / min and sinter it at a constant temperature for 4 hours to obtain a sintered body, i.e., a microwave dielectric ceramic material.

[0099] Comparative Example 2

[0100] A microwave dielectric ceramic material, the chemical expression of which is Li2MoO4;

[0101] Its preparation comprises the steps of:

[0102] ① According to the chemical expression Li2MoO4, calculate the mass of each raw material required. The raw materials are analytically pure, using 99.9wt% Li2CO3 and 99.9wt% MoO3 respectively.

[0103] ② Accurately weigh 99.9wt% Li2CO3 and 99.9wt% MoO3 raw materials and pour them into a ball mill, then add deionized water and ZrO2 grinding balls; the weight ratio of the three is: material: balls: deionized water = 1:2:1.5; after ball milling for 4 hours, the slurry is dried at 100℃ for 2h and sieved to obtain a mixture powder; the mixture powder is loaded into an alumina crucible and synthesized at 550℃ for 2h to obtain a Li2MoO4 synthetic block.

[0104] ③ Place the synthetic block in a ball mill for secondary ball milling, add deionized water and ZrO2 grinding balls; the weight ratio of the three is: material: balls: deionized water = 1:2:1.5; add a certain proportion of dispersant 0.3wt% to the slurry, grind for 2 hours, and then transfer to a sand mill for further refinement until the powder particle size D50 is less than 0.8μm; add a certain proportion of PVA polyvinyl alcohol 2wt% and PEG polyethylene glycol 1.5wt% to the above slurry for spray granulation to obtain granulated powder.

[0105] ④ Place the granulated powder into a mold and dry-press it at a pressure of 100 MPa to obtain a green sheet; keep the green sheet at 500°C for 2 hours to remove organic matter, then heat it to 600°C at a rate of 5°C / min and sinter it at a constant temperature for 4 hours to obtain a sintered body, i.e., a microwave dielectric ceramic material.

[0106] Comparative Example 3

[0107] A microwave dielectric ceramic material, the chemical formula of which is (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Li 0.4 )Al2O4, the preparation of which comprises the steps of:

[0108] ① Press (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Li 0.4 )Al2O4, calculate the mass of each raw material required. The raw materials are analytically pure, namely 99.9wt% MgO, 99.8wt% CoO, 99.9wt% ZnO, 99.8wt% NiO, 99.9wt% Li2CO3 and 99.9wt% Al2O3.

[0109] ② Accurately weigh the raw materials and pour them into a ball mill, then add deionized water and ZrO2 grinding balls; the weight ratio of the three is: material: balls: deionized water = 1:2:1.5; after ball milling for 4 hours, dry the slurry at 100°C for 2 hours, and sieve to obtain a mixture powder; load the mixture powder into an alumina crucible, calcinate at 1250°C for 2 hours to obtain a synthetic block.

[0110] ③ Place the synthetic block in a ball mill for secondary ball milling, add deionized water and ZrO2 grinding balls; the weight ratio of the three is: material: balls: deionized water = 1:2:1.5; add a certain proportion of dispersant 0.3wt% to the slurry, grind for 2 hours, and then transfer to a sand mill for further refinement until the powder particle size D50 is less than 0.8μm; add a certain proportion of PVA polyvinyl alcohol 2wt% and PEG polyethylene glycol 1.5wt% to the above slurry for spray granulation to obtain granulated powder.

[0111] ④ Place the granulated powder into a mold and dry-press it at a pressure of 100 MPa to obtain a green sheet; keep the green sheet at 500°C for 2 hours to remove organic matter, then increase the temperature to 1550°C at a heating rate of 5°C / min and sinter at a constant temperature for 4 hours to obtain a sintered body, i.e., a microwave dielectric ceramic material.

[0112] In order to verify the progress of the embodiments of the present application, the microwave dielectric properties of the microwave dielectric ceramic materials prepared in each embodiment and comparative example were tested using a vector network analyzer (Agilent 8722D) and a test single cavity and fixture instrument:

[0113] 1. Relative dielectric constant ε r Test method: The parallel plate resonance method (Hakki-Coleman method) is used to test the relative dielectric constant ε of the sample. r :

[0114] The cylindrical microwave dielectric ceramic material sample to be tested is placed at the center between two parallel metal plates to form a semi-enclosed transmission resonator. The upper metal plate can be moved up and down by adjusting the knob. Two probes are inserted on both sides of the sample to couple the input and output microwave signals. When the cavity resonates at a certain frequency, the cavity impedance reaches a minimum and the power passing through is maximized. The probes are connected to a microwave network analyzer, which can intuitively display the resonance characteristics of the cavity. Each resonance peak corresponds to a resonance mode. Raising the upper metal plate identifies the resonance peak moving toward a lower frequency as TE. 011 Mode. The test structure diagram is as shown in the attached Figure 2 During the test, the network analyzer (electronically calibrated), the test fixture, and the coaxial transmission line are connected in series to form a loop; the TE is found by adjusting the height of the upper metal plate and observing the drift of the resonance peak. 011 Then adjust the upper and lower metal plates to close contact with the sample and change the positions of the two probes to the optimal coupling state. Record its TE 011 The resonant frequency f0 of the mode resonance peak, combined with the height H and diameter D of the sample, can be used to calculate the dielectric constant ε of the sample through software. r .

[0115] 2. Test method of quality factor (Q×f): The closed-cavity method is used to test the quality factor Q of ceramic samples:

[0116] The closed cavity method is based on the open cavity method and the side walls of the upper and lower metal plates are closed. This not only effectively prevents the radiation of electromagnetic energy and improves the no-load quality factor, but also facilitates the test of the resonant frequency temperature coefficient. The test structure diagram is shown in the attached figure. Figure 3 As shown. It also uses the method of dielectric body resonance in the shielding cavity to measure the complex dielectric constant of low-loss, high dielectric constant materials. Among them, the high dielectric constant microwave dielectric ceramic material is placed on a low-loss, low dielectric constant polytetrafluoroethylene substrate, so that the electromagnetic field is in transmission mode inside the dielectric sample and in cutoff mode in the air medium and substrate outside the sample. In this way, the electromagnetic energy outside the dielectric sample can be minimized, so that the system has a high energy filling coefficient. Using TE 011 The model can not only avoid the gap coupling capacitance between the dielectric sample and the substrate, between the substrate and the conductive plate, and between the upper and lower conductive plates and the side walls, but also make the system have a higher unloaded quality factor (Q×f). The use of the metal closed cavity and the model can not only accurately measure the quality factor (Q×f) of the microwave dielectric material, but also facilitate the subsequent measurement of τ f Measurement of this parameter.

[0117] 3. Resonant frequency temperature coefficient τ f Test method: Use the attached Figure 3 The test equipment uses the temperature control device to change the temperature in the resonant cavity, and then records the resonant frequencies at multiple specified temperatures. The resonant frequency temperature coefficient τ can then be calculated through data fitting and other methods. f The calculation formula is as follows:

[0118]

[0119] Where: f T1 and f T2 Represent the resonant frequencies at temperatures T1 and T2 respectively.

[0120] The test results are shown in Table 1 below:

[0121] Table 1

[0122]

[0123]

[0124] From the above test results, it can be seen that the microwave dielectric ceramic materials prepared in Examples 1 to 7 of the present application have excellent microwave dielectric properties, and their relative dielectric constant ε rThe quality factor (Q×f) is as high as 49400~59200GHz, and the resonant frequency temperature coefficient τ f The relative dielectric constant ε of the microwave dielectric ceramic material prepared in Example 2 is -52 to -59 ppm / °C. r is 7.7; the quality factor (Q×f) value is as high as 59200GHz, and the resonant frequency temperature coefficient τ f The sintering temperature of the microwave dielectric ceramic materials prepared in Examples 1 to 7 of the present application is lower than 700°C, and they can be used in the LTCC process to co-fire with Ag electrodes to produce small-sized filters in Wifi 6E devices or high-speed substrates for millimeter waves.

[0125] The microwave dielectric ceramic material prepared in Comparative Example 1 contains only (Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4, the sintering temperature is as high as 900℃. The microwave dielectric ceramic material prepared in Comparative Example 2 contains only Li2MoO4, and the sintering temperature is only 600℃, but the relative dielectric constant ε r The quality factor (Q×f) is only 46000GHz, and the resonant frequency temperature coefficient τ f As high as -160ppm / ℃. 0.2 Co 0.2 Zn 0.2 Ni 0.2 Li 0.4 The sintering temperature of Al2O4 microwave dielectric ceramic material is as high as 1550°C. Obviously, the microwave dielectric ceramic material prepared in the comparative example has a high sintering temperature and poor microwave dielectric properties, making it unsuitable for use in the LTCC process when co-fired with Ag electrodes to make small-sized filters in Wi-Fi 6E devices or high-speed substrates for millimeter waves.

[0126] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A microwave dielectric ceramic material, characterized in that: The microwave dielectric ceramic material includes a ceramic solid solution with a chemical expression of xAMoO4-yLi2MoO4; wherein the A position includes at least five metal elements of Mg, Co, Zn, Ni, Mn, Cu, Fe, and Cr, the total molar content of the metal elements at the A position is 100%, 0<x<1, 0<y<1, and x+y=1.

2. The microwave dielectric ceramic material according to claim 1, wherein: The A site includes five metal elements in equal molar ratios.

3. The microwave dielectric ceramic material according to claim 2, wherein: The chemical expression of the ceramic solid solution is x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4-yLi2MoO4.

4. The microwave dielectric ceramic material according to any one of claims 1 to 3, characterized in that: 0.88≤x<1,0<y≤0.

12.

5. A method for preparing a microwave dielectric ceramic material, characterized in that: The following steps are involved: The raw material components are obtained according to the stoichiometric ratio of each element in the ceramic solid solution of the chemical expression xAMoO4-yLi2MoO4; wherein the A position includes at least five metal elements of Mg, Co, Zn, Ni, Mn, Cu, Fe, and Cr, the total molar content of the metal elements in the A position is 100%, 0<x<1, 0<y<1, and x+y=1; sintering AMoO4 synthetic blocks and Li2MoO4 synthetic blocks respectively; The AMoO4 synthetic block and the Li2MoO4 synthetic block are crushed, a dispersant is added to prepare a mixed powder, and a binder is added to mix and granulate to obtain a granulated powder; The granulated powder is made into a ceramic green body, which is subjected to a debinding process and a sintering process in sequence to form the ceramic solid solution of xAMoO4-yLi2MoO4, thereby obtaining a microwave dielectric ceramic material.

6. The method for preparing a microwave dielectric ceramic material according to claim 5, wherein: The step of firing the AMoO4 synthetic block comprises: ball milling the A source and the molybdenum source for 2 to 6 hours at a mass ratio of material, ball and water of 1:(1 to 3):(1 to 2), drying and sieving, and sintering at a temperature of 800 to 900° C. for 2 to 4 hours to obtain the AMoO4 synthetic block; And / or, the step of firing the Li2MoO4 synthetic block comprises: ball milling a lithium source and a molybdenum source for 2 to 6 hours at a mass ratio of material, ball and water of 1:(1 to 3):(1 to 2), drying and sieving, and then sintering at a temperature of 500 to 600° C. for 2 to 4 hours to obtain the Li2MoO4 synthetic block; And / or, the preparation of the mixed powder comprises the steps of: grinding the AMoO4 synthetic block and the Li2MoO4 synthetic block into powders respectively and then mixing them, and ball milling them to a particle size D50 not higher than 0.8 μm under the condition that the mass ratio of material, ball and water is 1:(1-3):(1-2); And / or, the mixing granulation method adopts spray granulation; And / or, the preparation of the ceramic green body comprises the steps of: adding the granulated powder into a mold, and dry pressing the mold under a pressure of 80 to 200 MPa to obtain the ceramic green body; And / or, the debinding treatment conditions include: keeping the temperature at 400-500° C. for 2-3 hours; And / or, the sintering treatment conditions include: heating to 600-700° C. at a rate of 1-10° C. / min and keeping the temperature for 2-4 hours.

7. The method for preparing a microwave dielectric ceramic material according to claim 6, wherein: The A source includes a magnesium source, a cobalt source, a zinc source, a nickel source and a manganese source; and / or, the dispersant comprises at least one of polyacrylamide, polycarboxylate ammonia salt, ammonium salt, and quaternary ammonium salt; And / or, the binder includes at least one of polyvinyl alcohol, polyvinyl butyral, and polyethylene glycol.

8. The method for preparing a microwave dielectric ceramic material according to any one of claims 5 to 7, wherein: The mass ratio of the dispersant to the mixed powder is (0.2-0.4):100; And / or, the mass ratio of the binder to the mixed powder is (2-4):100; And / or, the raw material components include at least one of metal oxides, metal hydroxides, and metal salts.

9. The method for preparing a microwave dielectric ceramic material according to claim 8, wherein: The microwave dielectric ceramic material contains a chemical formula of x(Mg 0.2 Co 0.2 Zn 0.2 Ni 0.2 Mn 0.2 )MoO4-yLi2MoO4 ceramic solid solution, 0.88≤x<1, 0<y≤0.

12.

10. A microwave dielectric ceramic device, characterized in that: The raw material components for preparing the microwave dielectric ceramic device include the microwave dielectric ceramic material according to any one of claims 1 to 4 or the microwave dielectric ceramic material prepared by the preparation method of the microwave dielectric ceramic material according to any one of claims 5 to 9.

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