ZnNb2O6-based (Ti1 / 2W1 / 2) 5 < + >-substituted Nb < 5 < + > microwave dielectric ceramic and preparation method thereof

Abstract

The invention belongs to the field of microwave dielectric ceramic materials, and particularly provides ZnNb2O6-based (Ti1 / 2W1 / 2) 5 + substituted Nb < 5 + > microwave dielectric ceramic and a preparation method thereof.A ZnNb2O6 system is adopted, and (Ti1 / 2W1 / 2) 5 + is introduced to replace Nb < 5 + >, so that the polarizability and lattice energy of the material are improved, the deformation quantity of an average oxygen octahedron is reduced, the grain boundary and grain are optimized, and the microwave dielectric ceramic has the advantages that the microwave dielectric ceramic is used for replacing Nb < 5 + > with Ti1 / 2W1 / 2) 5 +; therefore, the dielectric constant, quality factor and temperature stability of the material are improved. By introducing composite ions, the temperature coefficient is changed through interaction between the ions, and the frequency temperature stability is further improved; the microwave dielectric ceramic material with the dielectric constant of 24, Q * f = 120000 GHz and tau f =-100 ppm / DEG C is obtained, and the microwave dielectric ceramic material can be used in the fields of filters, antennas, resonant cavities and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave dielectric ceramic materials, and in particular relates to a microwave dielectric ceramic for high-frequency microwave devices with a high quality factor and good frequency and temperature stability, and a preparation method thereof. Background Art

[0002] With the continuous advancement of technology, the demand for high-reliability microwave components is increasing. These components, such as filters, resonant cavities, and antennas, play an indispensable role in fields such as communications and radar. To improve the performance of these components, research on microwave dielectric materials continues to deepen. In particular, low-loss microwave dielectric ceramic materials, due to their low dielectric loss and suitable dielectric constant, have been widely used in high-frequency, high-reliability components.

[0003] In high-frequency, high-reliability devices, the dielectric loss, dielectric constant, and temperature stability of the material are crucial. Although a variety of microwave materials are currently available, many have high dielectric loss and the resonant frequency temperature coefficient often does not meet the requirements. These factors limit the widespread application of materials in high-frequency microwave devices. Among all microwave dielectric ceramic materials, niobate ceramics not only have low dielectric loss but also have an intermediate dielectric constant. Therefore, they have broad application potential in high-frequency, high-reliability devices, especially in filters, antennas, resonant cavities and other fields. However, traditional niobate ceramics have a poor resonant frequency temperature coefficient, which not only increases production costs but may also lead to excessive grain growth or inhomogeneity in the material, thereby affecting device performance.

[0004] In recent years, researchers have introduced ion substitution to effectively improve the temperature coefficient of ceramics such as niobates, enhancing their quality factor and temperature stability in high-frequency applications. This has become a key approach to enhancing their potential for industrial application. Ion substitution can increase the material's polarizability and lattice energy, reduce the average oxygen octahedral deformation, and optimize grain boundaries and grains, thereby improving the material's dielectric constant, quality factor, and temperature stability. Summary of the Invention

[0005] The object of the present invention is to provide (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ The invention discloses a method for improving the quality factor and frequency temperature stability of zinc niobate microwave ceramics, so that the prepared zinc niobate microwave ceramics have a high quality factor and good frequency temperature stability, and are suitable for the application of high-frequency and high-reliability microwave devices. The invention adopts a zinc niobate system, by introducing (Ti 1 / 2W 1 / 2 ) 5+ Replace Nb 5+On the one hand, since the selected composite ions and the substituted ions have the same charge, they will not cause large lattice distortion, reduce the average crystal oxygen octahedron deformation, improve the lattice structure, thereby reducing losses and achieving a significant improvement in the quality factor; on the other hand, (Ti 1 / 2 W 1 / 2 ) 5+ When ions are substituted, the interaction between ions changes the temperature coefficient of the material, further improving the frequency temperature stability and obtaining a dielectric constant of 24, Q×f=120000GHz, τ f =-100ppm / ℃ microwave dielectric ceramic materials can be used in filters, antennas, resonant cavities and other fields.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A ZnNb2O6-based (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ The microwave dielectric ceramic and the preparation method thereof are characterized by comprising the following steps:

[0008] a. Using niobium oxide (Nb2O5, 99%), zinc oxide (ZnO, 99%), titanium dioxide (TiO2, 99%), and tungsten trioxide (WO3, 99.5%) as raw materials, according to ZnNb 2-x (TiW) x / 2 The main powder is obtained by mixing the ingredients in a stoichiometric ratio of the molecular formula O6;

[0009] b. Mix the raw materials prepared in a according to the mass ratio of material: deionized water: ball at 1:1:1.2-1.5, ball mill speed 250r / min-300r / min, ball milling time 8h-12h; then dry at 80℃-120℃ and pass through 40 mesh sieve;

[0010] c. Pre-sinter the ball-milled powder obtained in step b at 1000°C for 4 hours at a heating rate of 1°C / min to 2°C / min to obtain ZnNb 2-x (TiW) x / 2 O6 powder.

[0011] d. Add PVA aqueous solution (concentration of 8-12 wt%) to the powder obtained in c as a binder to form granules, and press them into shape at 18 MPa-20 MPa with a holding time of 2 min-3 min.

[0012] e. Sinter the sample formed by pressing in step d at 1100°C with a heating rate of 1°C / min to 2°C / min and a holding time of 4h to 6h; and allow it to cool naturally to obtain the ZnNb2-x( TiW) x / 2 O6 ceramic material.

[0013] Furthermore, in step a, the molar ratio of Nb2O5, ZnO, TiO2, and WO3 is 1.92-2:1:0-0.04:0-0.04.

[0014] Furthermore, in step b, the ball milling is performed in a planetary ball mill using deionized water as the solvent and zirconium balls as the milling medium for wet ball milling, wherein the mass ratio of raw material, solvent, and iron balls is 1:1:1.2-1.5, the ball milling time is 8-12 hours, and the ball milling speed is 250-300 r / min. Furthermore, in steps b and d, the drying temperature is 80°C and the drying time is 24 hours.

[0015] Furthermore, in step c, the pre-firing temperature is 1000° C., the holding time is 4 hours, and the heating rate is 1° C. / min to 2° C. / min.

[0016] Furthermore, in step d, the binder used is PVA with a concentration of 8 to 12 wt%, the pressure is 18 to 20 MPa, and the holding time is 2 to 3 minutes.

[0017] Furthermore, in step e, the heating rate is 1-2°C / min, the sintering temperature is 1050-1150°C, and the holding time is 4-6h.

[0018] Based on the above technical solution, the beneficial effects of the present invention are:

[0019] The present invention provides a (Ti based on ZnNb2O6 system 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ Microwave dielectric ceramics and preparation method thereof, using a solid phase method, through batching, primary ball milling, pre-sintering, secondary ball milling, granulation and high temperature sintering to prepare ZnNb 2-x( TiW) x / 2 O6 microwave dielectric ceramics; The present invention adopts ZnNb2O6 system by introducing (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ On the one hand, since the selected composite ions and the substituted ions have the same charge, they will not cause large lattice distortion, reduce the average crystal oxygen octahedron deformation, improve the lattice structure, thereby reducing losses and achieving a significant improvement in the quality factor; on the other hand, (Ti 1 / 2 W 1 / 2 ) 5+When ions are substituted, the interaction between ions changes the temperature coefficient of the material, further improving the frequency temperature stability, and finally obtaining a dielectric constant of 24, Q×f=120000GHz, τ f =-100ppm / ℃ microwave dielectric ceramic materials can be used in filters, antennas, resonant cavities and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 ZnNb in the embodiment of the invention 2-x( TiW) x / 2 X-ray diffraction pattern of O6 microwave dielectric ceramics.

[0021] Figure 2 ZnNb in the embodiment of the invention 2-x( TiW) x / 2 SEM micrograph of O6 microwave dielectric ceramic sintered at 1100℃.

[0022] Figure 3 ZnNb in the embodiment of the invention 2-x( TiW) x / 2 EDS distribution diagram of O6 microwave dielectric ceramics (x=0.02).

[0023] Figure 4 ZnNb in the embodiment of the invention 2-x( TiW) x / 2 Q×f values ​​of O6 microwave dielectric ceramics at different sintering temperatures.

[0024] Figure 5 ZnNb in the embodiment of the invention 2-x( TiW) x / 2 ε of O6 microwave dielectric ceramics at different sintering temperatures f value.

[0025] Figure 6 ZnNb in the embodiment of the invention 2-x( TiW) x / 2 τ of O6 microwave dielectric ceramics at different sintering temperatures f value. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0027] Example 1

[0028] This embodiment provides a ZnNb2O6-based (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+Microwave dielectric ceramic and preparation method thereof, the chemical expression of the magnesium niobate microwave dielectric ceramic is: ZnNb 1.98 (TiW) 0.01 O6, specifically including the following steps:

[0029] a. Using niobium oxide (Nb2O5, 99%), zinc oxide (ZnO, 99%), titanium dioxide (TiO2, 99%), and tungsten trioxide (WO3, 99.5%) as raw materials, according to ZnNb 1.98 (TiW) 0.01 The main powder is obtained by mixing the ingredients in a stoichiometric ratio of the molecular formula O6;

[0030] b. Mix the raw materials prepared in a according to the mass ratio of material: deionized water: ball at 1:1:1.2-1.5, ball mill speed 250r / min-300r / min, ball milling time 8h-12h; then dry at 80℃-120℃ and pass through 40 mesh sieve;

[0031] c. Pre-sinter the ball-milled powder obtained in step b at 1000°C for 4 hours at a heating rate of 1°C / min to 2°C / min to obtain ZnNb 1.98 (TiW) 0.01 O6 powder.

[0032] d. Add PVA aqueous solution (concentration of 8-12 wt%) to the powder obtained in c as a binder to form granules, and press them into shape at 18 MPa-20 MPa with a holding time of 2 min-3 min.

[0033] e. Sinter the sample pressed into shape in step (d) at 1050-1150°C with a heating rate of 1-2°C / min and a holding time of 4-6h; and allow it to cool naturally to obtain the ZnNb 1.98 (TiW )0.01 O6 ceramic material.

[0034] The ZnNb prepared in this example 1.98 (TiW) 0.01 O6 microwave dielectric ceramic material was tested. Among them, the X-ray diffraction pattern is as follows Figure 1 As shown, it is consistent with the standard diffraction peak of ZnNb2O6 (PDF#97-003-6290) and no new peak appears, which means that (Ti 1 / 2 W 1 / 2 ) 5+ The combined substitution of (Ti 1 / 2 W 1 / 2 ) 5+The combined substitution of ZnNb2O6 was successfully dissolved in the ZnNb2O6 lattice; SEM micrographs are shown in Figure 2 As shown in the figure, the grains are evenly distributed, the grain boundaries are clear and dense, and there are few defects inside the material; the EDS distribution diagram is as follows Figure 3 As shown, Zn, Nb, Ti, W and O are evenly distributed, indicating that (Ti 1 / 2 W 1 / 2 ) 5+ The ions have entered the crystal lattice and formed a solid solution; the Q×f value is as follows Figure 4 As shown, it is 120000GHz; ε f Value Figure 5 24 is shown; τ f Value Figure 6 Shown is -100ppm / °C.

[0035] Example 2

[0036] This embodiment provides a ZnNb2O6-based (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ Microwave dielectric ceramic and preparation method thereof, the chemical expression of the magnesium niobate microwave dielectric ceramic is: ZnNb 2( TiW)0O6, specifically comprising the following steps:

[0037] a. Using niobium oxide (Nb2O5, 99%), zinc oxide (ZnO, 99%), titanium dioxide (TiO2, 99%), and tungsten trioxide (WO3, 99.5%) as raw materials, the ingredients are mixed in the stoichiometric ratio according to the molecular formula of ZnNb2(TiW)0O6 to obtain the main powder;

[0038] b. Mix the raw materials prepared in a according to the mass ratio of material: deionized water: ball at 1:1:1.2-1.5, ball mill speed 250r / min-300r / min, ball milling time 8h-12h; then dry at 80℃-120℃ and pass through 40 mesh sieve;

[0039] c. Pre-sinter the ball-milled powder obtained in step b at 1000°C for 4 hours at a heating rate of 1°C / min to 2°C / min to obtain ZnNb2(TiW). 0. O6 powder.

[0040] d. Add PVA aqueous solution (concentration of 8-12 wt%) to the powder obtained in c as a binder to form granules, and press them into shape at 18 MPa-20 MPa with a holding time of 2 min-3 min.

[0041] e. Sinter the sample pressed into shape in step (d) at 1050-1150°C with a heating rate of 1-2°C / min and a holding time of 4-6h; and allow it to cool naturally to obtain the ZnNb2(TiW )0 O6 ceramic material.

[0042] The ZnNb2(TiW)0O6 microwave dielectric ceramic material prepared in this embodiment was tested. Among them, the X-ray diffraction pattern is as follows Figure 1 As shown; SEM micrographs as Figure 2 As shown; Q×f value is as Figure 4 Shown is 79000GHz; ε f Value Figure 5 23.3 is shown; τ f Value Figure 6 Shown is -77ppm / °C.

[0043] Example 3

[0044] This embodiment provides a ZnNb2O6-based (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ Microwave dielectric ceramic and preparation method thereof, the chemical expression of the magnesium niobate microwave dielectric ceramic is: ZnNb 1.96( TiW) 0.02 O6, specifically including the following steps:

[0045] a. Using niobium oxide (Nb2O5, 99%), zinc oxide (ZnO, 99%), titanium dioxide (TiO2, 99%), and tungsten trioxide (WO3, 99.5%) as raw materials, according to ZnNb 1.96 (TiW) 0.02 The main powder is obtained by mixing the ingredients in a stoichiometric ratio of the molecular formula O6;

[0046] b. Mix the raw materials prepared in a according to the mass ratio of material: deionized water: ball at 1:1:1.2-1.5, ball mill speed 250r / min-300r / min, ball milling time 8h-12h; then dry at 80℃-120℃ and pass through 40 mesh sieve;

[0047] c. Pre-sinter the ball-milled powder obtained in step b at 1000°C for 4 hours at a heating rate of 1°C / min to 2°C / min to obtain ZnNb 1.96 (TiW) 0.02 O6 powder.

[0048] d. Add PVA aqueous solution (concentration of 8-12 wt%) to the powder obtained in c as a binder to form granules, and press them into shape at 18 MPa-20 MPa with a holding time of 2 min-3 min.

[0049] e. Sinter the sample pressed into shape in step (d) at 1050-1150°C with a heating rate of 1-2°C / min and a holding time of 4-6h; and allow it to cool naturally to obtain the ZnNb 2-x (TiW )x / 2 O6 ceramic material.

[0050] The ZnNb prepared in this example 1.94 (TiW) 0.03 O6 microwave dielectric ceramic material was tested. Among them, the X-ray diffraction pattern is as follows Figure 1 As shown; SEM micrographs as Figure 2 As shown; Q×f value is as Figure 4 Shown is 103000GHz; ε f Value Figure 5 Shown is 23.8; τ f Value Figure 6 Shown is -125ppm / °C.

[0051] Example 4

[0052] This embodiment provides a ZnNb2O6-based (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ Microwave dielectric ceramic and preparation method thereof, the chemical expression of the magnesium niobate microwave dielectric ceramic is: ZnNb 1.94 (TiW) 0.03 O6, specifically including the following steps:

[0053] a. Using niobium oxide (Nb2O5, 99%), zinc oxide (ZnO, 99%), titanium dioxide (TiO2, 99%), and tungsten trioxide (WO3, 99.5%) as raw materials, according to ZnNb 1.94 (TiW) 0.03 The main powder is obtained by mixing the ingredients in a stoichiometric ratio of the molecular formula O6;

[0054] b. Mix the raw materials prepared in a according to the mass ratio of material: deionized water: ball at 1:1:1.2-1.5, ball mill speed 250r / min-300r / min, ball milling time 8h-12h; then dry at 80℃-120℃ and pass through 40 mesh sieve;

[0055] c. Pre-sinter the ball-milled powder obtained in step b at 1000°C for 4 hours at a heating rate of 1°C / min to 2°C / min to obtain ZnNb 1.94 (TiW) 0.03 O6 powder.

[0056] d. Add PVA aqueous solution (concentration of 8-12 wt%) to the powder obtained in c as a binder to form granules, and press them into shape at 18 MPa-20 MPa with a holding time of 2 min-3 min.

[0057] e. Sinter the sample pressed into shape in step (d) at 1050-1150°C with a heating rate of 1-2°C / min and a holding time of 4-6h; and allow it to cool naturally to obtain the ZnNb 1.94 (TiW )0.03 O6 ceramic material.

[0058] The ZnNb prepared in this example 1.94 (TiW) 0.03 O6 microwave dielectric ceramic material was tested. Among them, the X-ray diffraction pattern is as follows Figure 1 As shown; SEM micrographs as Figure 2 As shown; Q×f value is as Figure 4 Shown is 95000GHz; ε f Value Figure 5 Shown is 23.9; τ f Value Figure 6 Shown is -140ppm / °C.

[0059] Example 5

[0060] This embodiment provides a ZnNb2O6-based (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ Microwave dielectric ceramic and preparation method thereof, the chemical expression of the magnesium niobate microwave dielectric ceramic is: ZnNb 1.92 (TiW) 0.04 O6, specifically including the following steps:

[0061] a. Using niobium oxide (Nb2O5, 99%), zinc oxide (ZnO, 99%), titanium dioxide (TiO2, 99%), and tungsten trioxide (WO3, 99.5%) as raw materials, according to ZnNb 1.92 (TiW) 0.04 The main powder is obtained by mixing the ingredients in a stoichiometric ratio of the molecular formula O6;

[0062] b. Mix the raw materials prepared in a according to the mass ratio of material: deionized water: ball at 1:1:1.2-1.5, ball mill speed 250r / min-300r / min, ball milling time 8h-12h; then dry at 80℃-120℃ and pass through 40 mesh sieve;

[0063] c. Pre-sinter the ball-milled powder obtained in step b at 1000°C for 4 hours at a heating rate of 1°C / min to 2°C / min to obtain ZnNb 1.98 (TiW) 0.01 O6 powder.

[0064] d. Add PVA aqueous solution (concentration of 8-12 wt%) to the powder obtained in c as a binder to form granules, and press them into shape at 18 MPa-20 MPa with a holding time of 2 min-3 min.

[0065] e. Sinter the sample pressed into shape in step (d) at 1050-1150°C with a heating rate of 1-2°C / min and a holding time of 4-6h; and allow it to cool naturally to obtain the ZnNb 1.92 (TiW )0.04 O6 ceramic material.

[0066] The ZnNb prepared in this example 1.92 (TiW) 0.04 O6 microwave dielectric ceramic material was tested. Among them, the X-ray diffraction pattern is as follows Figure 1 As shown; SEM micrographs as Figure 2 As shown; Q×f value is as Figure 4 Shown is 91000GHz; ε f Value Figure 5 24.2 is shown; τ f Value Figure 6 Shown is -158ppm / °C.

[0067] By comparison, it is found that the sample obtained by sintering at 1100℃ for 4h in Example 1 has the best performance, with a dielectric constant of 24, Q×f=120000GHz, τ f =-100ppm / ℃

[0068] The above description is only a specific embodiment of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes; all disclosed features, or all steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A ZnNb2O6-based (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ The microwave dielectric ceramic and the preparation method thereof are characterized in that: The following steps are involved: a. Using niobium oxide (Nb2O5, 99%), zinc oxide (ZnO, 99%), titanium dioxide (TiO2, 99%), and tungsten trioxide (WO3, 99.5%) as raw materials, according to the stoichiometric ratio of ZnNb 2-x (TiW) x / 2 O6 molecular formula (0 < x ≤ 0.08) for batching, and obtaining the main powder body. b. Mix the raw materials prepared in a according to the mass ratio of material: deionized water: ball at 1:1:1.2-1.5, ball mill speed 250r / min-300r / min, ball milling time 8h-12h; then dry at 80℃-120℃ and pass through 40 mesh sieve; c. Pre-sinter the ball-milled powder obtained in step b at 1000°C for 4 hours at a heating rate of 1°C / min to 2°C / min to obtain ZnNb 2-x (TiW) x / 2 O6 powder. d. Add PVA aqueous solution (concentration of 8-12 wt%) to the powder obtained in c as a binder to form granules, and press them into shape at 18 MPa-20 MPa with a holding time of 2 min-3 min. e. Sinter the sample pressed into shape in step (d) at 1050-1150°C with a heating rate of 1-2°C / min and a holding time of 4-6h; and allow it to cool naturally to obtain the ZnNb 2-x (TiW )x / 2 O6 ceramic material.

2. A ZnNb2O6-based (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ The microwave dielectric ceramic and the preparation method thereof are characterized in that: In step a, the molar ratio of Nb2O5, ZnO, TiO2, and WO3 is 1.92-2:1:0-0.04:0-0.

04.

3. A ZnNb2O6-based (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ The microwave dielectric ceramic and the preparation method thereof are characterized in that: In step b, ball milling is carried out in a planetary ball mill, using deionized water as a solvent and zirconium balls as a ball milling medium for wet ball milling, wherein the mass ratio of raw material, solvent and iron ball is 1:1:1.2-1.5, the ball milling time is 8-12 hours, and the ball milling speed is 250-300 r / min.

4. According to claim 1 based on ZnNb2O6 (Ti 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ The microwave dielectric ceramic and the preparation method thereof are characterized in that: In step c, the pre-firing temperature is 1000° C., the holding time is 4 hours, and the heating rate is 1° C. / min to 2° C. / min.

5. The ZnNb2O6-based (Ti) 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ The microwave dielectric ceramic and the preparation method thereof are characterized in that: In step d, the binder used is PVA with a concentration of 8 to 12 wt%, the pressure is 18 to 20 MPa, and the holding time is 2 to 3 minutes.

6. The ZnNb2O6-based (Ti) 1 / 2 W 1 / 2 ) 5+ Replace Nb 5+ The microwave dielectric ceramic and the preparation method thereof are characterized in that: In step e, the heating rate is 1-2°C / min, the sintering temperature is 1050-1150°C, and the holding time is 4-6h.

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