Vanadium-based zircon microwave dielectric ceramic and preparation method thereof

Abstract

The present application relates to the technical field of ceramic materials, and particularly relates to a vanadium-based zircon microwave dielectric ceramic and a preparation method thereof. 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 )VO4, the chemical formula is (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 )VO4, the chemical formula is (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 )VO4, the chemical formula is (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 )VO4, the chemical formula is (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 )VO4, the chemical formula is (Bi

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a vanadium-based zircon microwave dielectric ceramic and its preparation method. Background Technology

[0002] Microwave dielectric ceramics (MWDC) are a new type of functional ceramic material used in microwave frequency circuits (mainly UHF and SHF bands). MWDC possesses excellent microwave dielectric properties, including low high-frequency dielectric loss, moderate dielectric constant, and adjustable temperature coefficient of resonant frequency. It is a fundamental and key material for fabricating microwave electronic components such as dielectric substrates, filters, resonators, and oscillators. The three main indicators for evaluating the performance of microwave dielectric materials are dielectric constant, quality factor, and temperature coefficient of resonant frequency.

[0003] With the development of 5G / 6G communication technologies, the high-frequency and high-bandwidth characteristics necessitate denser macro and micro base stations to ensure full signal coverage. This will inevitably create huge market demand for microwave dielectric ceramic materials and components (dielectric antennas, dielectric filters, and substrates), thus placing higher demands on the selection of microwave dielectric ceramic materials. To enable devices to possess wider frequency selectivity, high-speed signal transmission, and good stability, industrial applications require high quality factor (Q×f) and near-zero temperature coefficient of resonant frequency (τ). f ) and has a low dielectric constant (ε) r Microwave dielectric ceramic materials with a Q×f value <20. However, the vast majority of high-Q×f single-phase low-dielectric (ε) materials... r <20) Ceramics typically exhibit a large negative τ. f Values ​​(-20 to -80 ppm / ℃), such as the ε value of cubic spinel structured (Zn / Mg)Al2O4 ceramics. r Between 8.5 and 9.0, the Q×f value reaches as high as 56,000–100,000 GHz, however τ f Its value is between -70 and -80 ppm / ℃, exhibiting a low dielectric constant ε. r (10–13.5) wolframite-structured (Mg / Zn)WO4 ceramics exhibit high Q×f values ​​(62800 GHz) and large negative τ values. f Value (-30 to -64 ppm / ℃), larger negative τ f The value is not conducive to ensuring the operating temperature stability of the device, making it difficult to apply to the production and use of electronic devices.

[0004] Vanadium-based zircon-type (chemical formula AVO4) microwave dielectric ceramics are characterized by their low ε r And sintering temperature, high Q×f value (30000~60000GHz) and adjustable τ f This has attracted considerable attention from researchers. (Bi)1-x Ce x )VO4 and (Bi 1-x Ho x In VO4, ion substitution can be used to adjust the sintering temperature of ceramics and obtain near-zero τ. f In recent years, high-entropy alloys have gradually become a solution for designing high-performance materials in the materials industry. The concept of high entropy originated from HEAs proposed in 2004, which are single-phase solid solutions formed by five or more metallic elements in an equimolar ratio. High entropy, lattice distortion, hysteresis diffusion, and the cocktail effect are introduced to enhance their properties. Therefore, in recent years, many researchers have conducted research on high-entropy ceramics, high-entropy glasses, and high-entropy polymers. It has been reported that solid solutions formed through the high-entropy effect may achieve properties far exceeding those of the original materials, and therefore can be applied to the development of microwave dielectric ceramic materials with excellent microwave dielectric properties.

[0005] In summary, exploring and developing single-phase low-dielectric microwave dielectric ceramics with near-zero resonant frequency temperature coefficient and low loss to obtain microwave dielectric ceramic materials that can meet diverse practical applications has become a key research direction in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a vanadium-based zircon microwave dielectric ceramic and its preparation method, aiming to develop a single-phase low-dielectric microwave dielectric ceramic with a near-zero resonant frequency temperature coefficient and low loss.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a vanadium-based zircon microwave dielectric ceramic, wherein the constituent materials of the vanadium-based zircon microwave dielectric ceramic include Bi₂O₃, La₂O₃, CeO₂, Nd₂O₃, Sm₂O₃, and NH₄VO₃, and the chemical formula is: (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 )VO4.

[0008] The vanadium-based zircon microwave dielectric ceramic has a dielectric constant ranging from 16.1 to 17.3, a quality factor ranging from 41,000 to 47,500 GHz, and a resonant frequency temperature coefficient ranging from +10.5 ppm / ℃ to +13.2 ppm / ℃.

[0009] In a second aspect, the present invention also provides a method for preparing vanadium-based zircon microwave dielectric ceramics, for preparing vanadium-based zircon microwave dielectric ceramics as described in the first aspect above, characterized by comprising the following steps:

[0010] Based on the composition of vanadium-based zircon microwave dielectric ceramics, Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 powders were obtained by weighing and batching to obtain the original powder.

[0011] The original powder is stirred and mixed, and then subjected to wet milling and drying treatment in sequence to obtain dried powder. The dried powder is then pre-calcined in an atmospheric atmosphere at 800°C for 4 to 8 hours to obtain pre-sintered powder.

[0012] A binder is added to the pre-sintered powder to granulate it, and then it is pressed into shape. Finally, it is sintered in an atmospheric atmosphere at 850-920℃ for 4-8 hours to obtain vanadium-based zircon microwave dielectric ceramic.

[0013] The molar ratio of Bi2O3, La2O3, CeO2, Nd2O3 and Sm2O3 is 1:1:1:1:1, the wet milling time is 6 to 12 hours, and the ball milling medium is anhydrous ethanol.

[0014] The binder is a 5% polyvinyl alcohol solution, and the added mass of the binder accounts for 3% of the total mass of the original powder.

[0015] This invention discloses a vanadium-based zircon microwave dielectric ceramic and its preparation method. The method involves weighing and wet-milling raw powders of Bi₂O₃, La₂O₃, CeO₂, Nd₂O₃, Sm₂O₃, and NH₄VO₃ according to a specified ratio, drying the powder, pre-sintering it to obtain a pre-sintered powder, adding a binder, granulating the powder, pressing it into shape, and then sintering it to obtain a vanadium-based zircon microwave dielectric ceramic material with a near-zero positive resonant frequency temperature coefficient (τ). f Its temperature stability is good, with a near-zero dielectric constant (+10.5~+13.2ppm / ℃); its dielectric constant (ε) is also good. r The quality factor (Q×f) reached 16.1–17.3, and the quality factor (Q×f) value was between 41000 and 47500 GHz. This preparation method yielded a single-phase, pure-phase (Bi) 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 VO4 microwave dielectric ceramic material has a near-zero temperature coefficient of resonant frequency without the need for the addition of modifying materials, which can ensure the thermal stability of the device. It can be widely used in the manufacture of various dielectric antenna substrates, resonators and filters and other microwave devices. At the same time, microwave dielectric ceramic is not hygroscopic, has a stable crystal structure, and is suitable for mass production. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart illustrating the steps of preparing a vanadium-based zircon microwave dielectric ceramic material with a near-zero positive resonant frequency temperature coefficient, as described in Examples 1-4 of the present invention.

[0018] Figure 2 A vanadium-based zircon microwave dielectric ceramic (Bi) with a near-zero positive resonant frequency temperature coefficient was prepared as described in Example 3 of the present invention. 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 X-ray diffraction (XRD) pattern of VO4.

[0019] Figure 3 A vanadium-based zircon microwave dielectric ceramic (Bi) with a near-zero positive resonant frequency temperature coefficient was prepared as described in Example 3 of the present invention. 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 )Scanning electron microscope (SEM) image of the surface morphology of VO4.

[0020] Figure 4 This is a flowchart of a method for preparing vanadium-based zircon microwave dielectric ceramics provided by the present invention. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] In a first aspect, the present invention provides a vanadium-based zircon microwave dielectric ceramic, wherein the constituent ingredients of the vanadium-based zircon microwave dielectric ceramic include Bi₂O₃, La₂O₃, CeO₂, Nd₂O₃, Sm₂O₃ and NH₄VO₃, and the chemical formula is: (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 )VO4.

[0023] In this embodiment of the invention, the dielectric constant of the vanadium-based zircon microwave dielectric ceramic ranges from 16.1 to 17.3, the quality factor ranges from 41000 to 47500 GHz, the temperature coefficient of the resonant frequency ranges from +10.5 ppm / ℃ to +13.2 ppm / ℃, and the pure phase (Bi) 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 VO4 microwave dielectric ceramic material has a near-zero temperature coefficient of resonant frequency without the need for the addition of modifying materials, which can ensure the thermal stability of the device. It can be widely used in the manufacture of various dielectric antenna substrates, resonators and filters and other microwave devices. At the same time, microwave dielectric ceramic is not hygroscopic, has a stable crystal structure, and is suitable for mass production.

[0024] Please see Figures 1-4 Secondly, the present invention also provides a method for preparing vanadium-based zircon microwave dielectric ceramics, for preparing vanadium-based zircon microwave dielectric ceramics as described in the first aspect above, characterized by comprising the following steps:

[0025] S1 is based on the composition of vanadium-based zircon microwave dielectric ceramics to weigh and prepare powders of Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3, and obtain the original powder.

[0026] In this embodiment of the invention, the molar ratio of Bi2O3, La2O3, CeO2, Nd2O3 and Sm2O3 is 1:1:1:1:1.

[0027] S2 Stir and mix the original powder, and then perform wet milling and drying treatment in sequence to obtain dried powder. Pre-calcinate the powder in an atmospheric atmosphere at 800°C for 4 to 8 hours to obtain pre-sintered powder.

[0028] In this embodiment of the invention, the wet milling time is 6 to 12 hours, and the ball milling medium is anhydrous ethanol.

[0029] S3 adds a binder to the pre-sintered powder to granulate it, presses it into shape, and finally sintersulates it in an atmospheric atmosphere at 850-920℃ for 4-8 hours to obtain vanadium-based zircon microwave dielectric ceramic.

[0030] In this embodiment of the invention, the binder is a 5% polyvinyl alcohol solution, and the added mass of the binder accounts for 3% of the total mass of the original powder.

[0031] To better understand this technical solution, the following embodiments are provided for further explanation:

[0032] Example 1

[0033] A method for preparing a vanadium-based zircon microwave dielectric ceramic material with a near-zero positive resonant frequency temperature coefficient, comprising the following steps:

[0034] (1) The original powders of Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 with a purity >99.9% were mixed according to (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 The composition of VO4 was weighed and mixed, wherein the molar ratio of Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 was 1:1:1:1:1;

[0035] (2) Mix the raw materials from step (1) by wet ball milling for 6 hours. The ball milling medium is anhydrous ethanol. After drying, pre-calcine in an atmospheric atmosphere at 800°C for 4 hours.

[0036] (3) After adding a binder to the powder obtained in step (2) and granulating it, it is pressed into shape and finally sintered in an atmospheric atmosphere at 850°C for 4 hours; the binder is a polyvinyl alcohol solution with a mass concentration of 5%, and the amount of polyvinyl alcohol added accounts for 3% of the total mass of the powder.

[0037] Example 2

[0038] A method for preparing a vanadium-based zircon microwave dielectric ceramic material with a near-zero positive resonant frequency temperature coefficient, comprising the following steps:

[0039] (1) The original powders of Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 with a purity >99.9% were mixed according to (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 The composition of VO4 was weighed and mixed, wherein the molar ratio of Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 was 1:1:1:1:1;

[0040] (2) Mix the raw materials from step (1) by wet ball milling for 6 hours. The ball milling medium is anhydrous ethanol. After drying, pre-calcine in an atmospheric atmosphere at 800°C for 4 hours.

[0041] (3) After adding a binder to the powder obtained in step (2) and granulating it, it is pressed into shape and finally sintered in an atmospheric atmosphere at 870°C for 4 hours; the binder is a polyvinyl alcohol solution with a mass concentration of 5%, and the amount of polyvinyl alcohol added accounts for 3% of the total mass of the powder.

[0042] Example 3

[0043] A method for preparing a vanadium-based zircon microwave dielectric ceramic material with a near-zero positive resonant frequency temperature coefficient, comprising the following steps:

[0044] (1) The original powders of Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 with a purity >99.9% were mixed according to (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 The composition of VO4 was weighed and mixed, wherein the molar ratio of Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 was 1:1:1:1:1;

[0045] (2) Mix the raw materials from step (1) by wet ball milling for 6 hours. The ball milling medium is anhydrous ethanol. After drying, pre-calcine in an atmospheric atmosphere at 800°C for 4 hours.

[0046] (3) After adding a binder to the powder obtained in step (2) and granulating it, it is pressed into shape and finally sintered in an atmospheric atmosphere at 890°C for 4 hours; the binder is a polyvinyl alcohol solution with a mass concentration of 5%, and the amount of polyvinyl alcohol added accounts for 3% of the total mass of the powder.

[0047] Figure 2 Example 3: A vanadium-based zircon microwave dielectric ceramic (Bi) with a near-zero positive resonant frequency temperature coefficient. 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 X-ray diffraction (XRD) pattern of VO4. As can be seen from the figure, (Bi... 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 The vanadium-based zircon microwave dielectric ceramic exhibits a pure tetragonal zircon structure, consistent with the PDF card PDF#01-072-0859 for NdVO4. No impurity phases were found, indicating the potential for obtaining a single-phase material. This demonstrates the feasibility and effectiveness of a method for preparing vanadium-based zircon microwave dielectric ceramics with a near-zero positive resonant frequency temperature coefficient. The method is simple and has low production costs.

[0048] Figure 3 A vanadium-based zircon microwave dielectric ceramic (Bi) with a near-zero positive resonant frequency temperature coefficient was prepared as described in Example 3. 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm0.2 The image shows a scanning electron microscope (SEM) image of VO4. The image reveals that the prepared ceramic grains are uniform in size, dense in structure, and free of obvious pores and second phases. This indicates that a method for preparing vanadium-based zircon microwave dielectric ceramic materials with a near-zero positive resonant frequency temperature coefficient is feasible and effective. This method can yield relatively dense (Bi)4-based zircon microwave dielectric ceramics. 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 VO4 microwave dielectric ceramic material.

[0049] Example 4

[0050] A method for preparing a vanadium-based zircon microwave dielectric ceramic material with a near-zero positive resonant frequency temperature coefficient, comprising the following steps:

[0051] (1) The original powders of Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 with a purity >99.9% were mixed according to (Bi 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 The composition of VO4 was weighed and mixed, wherein the molar ratio of Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 was 1:1:1:1:1;

[0052] (2) Mix the raw materials from step (1) by wet ball milling for 6 hours. The ball milling medium is anhydrous ethanol. After drying, pre-calcine in an atmospheric atmosphere at 800°C for 4 hours.

[0053] (3) After adding a binder to the powder obtained in step (2) and granulating it, it is pressed into shape and finally sintered in an atmospheric atmosphere at 920°C for 4 hours; the binder is a polyvinyl alcohol solution with a mass concentration of 5%, and the amount of polyvinyl alcohol added accounts for 3% of the total mass of the powder.

[0054] Furthermore, this invention uses the cylindrical dielectric resonator method to evaluate the microwave dielectric properties. Specifically, the Hakki-Coleman method is used to measure the dielectric constant of the solid material, εr, which can only be measured at a resonant frequency corresponding to the TE011 mode. To avoid conduction and radiation losses, the Q value of the microwave dielectric ceramic sample can be measured using the resonant cavity method, where the sample is placed in a low-loss spaced cavity. The temperature coefficient of resonant frequency (τf) can be used to measure the stability of devices made from the material under different operating environments; it represents the "drift" of the resonant frequency with temperature changes. The relationship between resonant frequency and temperature is as follows:

[0055]

[0056] In the formula, f0 is the initial resonant frequency, Δf is the change in resonant frequency, and ΔT is the temperature change. The properties of the prepared microwave dielectric ceramic are shown in Table 1.

[0057] Table 1. Microwave dielectric properties of vanadium-based zircon microwave dielectric ceramics prepared in Examples 1 to 4.

[0058]

[0059] As shown in Table 1, the prepared vanadium-based zircon microwave dielectric ceramic material exhibits a near-zero temperature coefficient of resonant frequency τf (+10.5~+13.2ppm / ℃) and excellent temperature stability; its dielectric constant reaches 16.1~17.3, and its quality factor (Q×f) value is between 41000~47500GHz. Furthermore, the prepared (Bi... 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 VO4 microwave dielectric ceramics are single-phase, not easily deliquescent, have a stable crystal structure, and are suitable for mass production. The prepared (Bi) 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 VO4 microwave dielectric ceramic material has a near-zero temperature coefficient of resonant frequency without the need for modification, ensuring the thermal stability of devices. It can be widely used in the manufacture of various dielectric antenna substrates, resonators, and filters, among other microwave devices. Specifically, it can be used to produce microwave components, including but not limited to microwave resonators, filters, oscillators, or dielectric antennas.

[0060] The above description is merely a preferred embodiment of the vanadium-based zircon microwave dielectric ceramic and its preparation method according to the present invention. Of course, it should not be construed as limiting the scope of the present invention. Those skilled in the art can understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A vanadium-based zircon microwave dielectric ceramic, characterized in that... ； The vanadium-based zircon microwave dielectric ceramic comprises Bi₂O₃, La₂O₃, CeO₂, Nd₂O₃, Sm₂O₃, and NH₄VO₃, with the chemical formula: (Bi₂O₃, La₂O₃, CeO₂, Nd₂O₃, Sm₂O₃, and NH₄VO� 0.2 La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 )VO4.

2. The vanadium-based zircon microwave dielectric ceramic as described in claim 1, characterized in that... ； The vanadium-based zircon microwave dielectric ceramic has a dielectric constant ranging from 16.1 to 17.3, a quality factor ranging from 41,000 to 47,500 GHz, and a resonant frequency temperature coefficient ranging from +10.5 ppm / ℃ to +13.2 ppm / ℃.

3. A method for preparing vanadium-based zircon microwave dielectric ceramics, used to prepare the vanadium-based zircon microwave dielectric ceramics as described in any one of claims 1-2, characterized in that, Includes the following steps: Based on the composition of vanadium-based zircon microwave dielectric ceramics, Bi2O3, La2O3, CeO2, Nd2O3, Sm2O3 and NH4VO3 powders were obtained by weighing and batching to obtain the original powder. The original powder is stirred and mixed, and then subjected to wet milling and drying treatment in sequence to obtain dried powder. The dried powder is then pre-calcined in an atmospheric atmosphere at 800°C for 4 to 8 hours to obtain pre-sintered powder. A binder is added to the pre-sintered powder to granulate it, and then it is pressed into shape. Finally, it is sintered in an atmospheric atmosphere at 850-920℃ for 4-8 hours to obtain vanadium-based zircon microwave dielectric ceramic.

4. The method for preparing vanadium-based zircon microwave dielectric ceramics as described in claim 3. Its characteristics are: The molar ratio of Bi2O3, La2O3, CeO2, Nd2O3 and Sm2O3 is 1:1:1:1:1, the wet milling time is 6 to 12 hours, and the ball milling medium is anhydrous ethanol.

5. The method for preparing vanadium-based zircon microwave dielectric ceramics as described in claim 3, Its characteristics are: The binder is a 5% polyvinyl alcohol solution, and the added mass of the binder accounts for 3% of the total mass of the original powder.

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