A method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect

Abstract

The present invention belongs to the field of microwave dielectric ceramic materials, and specifically provides a method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect, so that the prepared zinc magnesium titanium microwave dielectric ceramic material has a low dielectric constant and a low dielectric loss, and is suitable for manufacturing ceramic substrates with excellent performance. The present invention uses the Zn 0.7 Mg 0.3 TiO3 system. Starting from the original particle size of the raw materials, micron-sized titanium dioxide raw materials are used as the main skeleton, and nano-sized zinc oxide and magnesium oxide raw materials are used as sintering fillers to form a cemented structure similar to concrete. This structure can greatly improve the sintering characteristics, avoid the generation of bubbles, and enhance the mechanical strength of the ceramics. Finally, the present invention uses the skeleton effect (particle size effect) to improve the sinterability of Zn 0.7 Mg 0.3 TiO3 microwave dielectric ceramics, and obtains a microwave dielectric ceramic material with a dielectric constant of 21.714, Q×f = 48486.6, and a resonance frequency temperature stability coefficient of -46.3 ppm / °C, which is expected to be used for manufacturing ceramic substrates.

Description

Technical Field

[0001] The present invention belongs to the field of microwave dielectric ceramic materials, and provides a method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect. The prepared microwave dielectric ceramic material has a low dielectric constant and dielectric loss, and is suitable for manufacturing ceramic substrates with excellent performance. Background Art

[0002] Zn 0.7 Mg 0.3 TiO3 materials are often used in electronic components, such as dielectric substrates and dielectric antennas in 5G communication circuits, and microwave frequency devices in filters and resonators. As a new type of electronic material, microwave dielectric ceramics exhibit excellent performance, high reliability, small volume, etc.; their rich physical and chemical properties depend on many factors, such as phase composition, sintering temperature, and synthesis method, and many scholars have conducted extensive research on these aspects; however, the influence of raw materials of various particle sizes on their physical and chemical properties is unknown. Therefore, the research focus of the present invention is to conduct modification research on zinc magnesium titanium microwave ceramics by controlling the particle size.

[0003] Generally, the finer the powder particles, the closer their contact, the shorter the diffusion path in the sintering chamber, and the greater the sintering driving force - surface energy; however, when the powder particles are too fine, the grains grow rapidly during high-temperature sintering, which may lead to abnormal growth, and at the same time, impurities may be adsorbed due to high surface activity. Currently, the Zn 0.7 Mg 0.3 TiO3 microwave dielectric ceramic materials synthesized by the conventional solid-phase method have high dielectric loss and high resonant cavity frequency temperature coefficient; in order to improve their sinterability, the present invention controls the particle sizes of raw materials such as zinc oxide, magnesium oxide, and titanium dioxide, and uses the particle size effect of the material to make it have more excellent performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect, so that the prepared zinc magnesium titanium microwave dielectric ceramic material has a low dielectric constant and low dielectric loss, and is suitable for manufacturing ceramic substrates with excellent performance. The present invention adopts the Zn 0.7 Mg 0.3 TiO3 system. Starting from the original particle size of the raw materials, micron-sized titanium dioxide raw materials are used as the main skeleton, and nano-sized zinc oxide and magnesium oxide raw materials are used as sintering fillers to form a cementitious structure similar to concrete, which can greatly improve the sintering characteristics, avoid the generation of bubbles, and enhance the mechanical strength of the ceramic; finally, the present invention uses the skeleton effect (particle size effect) to improve the Zn 0.7 Mg 0.3The sinterability of TiO3 microwave dielectric ceramics was studied, and microwave dielectric ceramic materials with a dielectric constant of 21.714, Q×f = 48486.6, and a temperature coefficient of resonant frequency of -46.3 ppm / °C were obtained, which are expected to be used in the manufacture of ceramic substrates.

[0005] To achieve the above object, the technical solution adopted in the present invention is as follows:

[0006] A method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect, characterized by comprising the following steps:

[0007] a. Using zinc oxide powder, magnesium oxide powder, and titanium dioxide powder as raw materials, weighing and mixing the raw materials according to the composition of Zn 0.7 Mg 0.3 TiO3; wherein, each raw material is composed of powders with two particle sizes, namely 25 - 50 wt% of micron-sized (particle size) powders and 50 - 75 wt% of nano-sized (particle size) powders;

[0008] b. Ball-milling the mixed raw materials once. After the ball-milling is completed, drying and grinding the slurry to obtain precursor powder;

[0009] c. Calcining the precursor powder at 850°C - 950°C for 2 - 4 hours to obtain a pre-sintered material;

[0010] d. Ball-milling the pre-sintered material twice. After the ball-milling is completed, drying and grinding the slurry to obtain Zn 0.7 Mg 0.3 TiO3 powder;

[0011] e. Granulating the Zn 0.7 Mg 0.3 TiO3 powder with polyvinyl alcohol binder, and pressing and forming it into a green body after sieving;

[0012] f. Sintering the green body at 1150°C - 1200°C for 4 - 6 hours to obtain zinc magnesium titanium microwave ceramic materials.

[0013] Further, in step a, for the three raw materials, the ratio of micron-sized powder to nano-sized powder can be the same or different.

[0014] Further, in steps b and d, the first ball-milling and the second ball-milling both adopt the same wet ball-milling. The wet ball-milling is carried out in a planetary ball mill, using deionized water and absolute ethanol as solvents and agate beads as ball-milling media for wet ball-milling. Among them, the mass ratio of raw materials to solvents is 1:1.5, the volume ratio of deionized water to absolute ethanol in the solvent is 1:1, and the ball-milling time is 12 hours.

[0015] Further, in steps b and d, the drying temperature is 85°C and the drying time is 24 hours.

[0016] Further, in step e, the dosage of the binder is 10 - 15 ml; the sieving process is as follows: sieving through 40 - mesh and 100 - mesh in sequence, and taking the particles between 40 - mesh and 100 - mesh; the pressure for briquetting is 15 - 20 Kg / cm 2 , the time is 2 - 3 minutes, and a cylindrical green body is pressed.

[0017] Based on the above - mentioned technical solution, the beneficial effects of the present invention are as follows:

[0018] The present invention provides a method for growing zinc - magnesium - titanium microwave ceramics based on the skeleton effect. Using the solid - phase method, Zn 0.7 Mg 0.3 TiO3 microwave dielectric ceramics are prepared through batching, primary ball - milling, pre - sintering, secondary ball - milling, granulation, and high - temperature sintering; on the basis of the solid - phase method, starting from the raw material particle sizes of the Zn 0.7 Mg 0.3 TiO3 system, by controlling the raw material particle sizes of zinc oxide powder, magnesium oxide powder, and titanium dioxide powder, the sinterability of Zn 0.7 Mg 0.3 TiO3 microwave dielectric ceramics is significantly improved by using the skeleton effect (particle - size effect); specifically, micron - level titanium dioxide raw materials are used as the main skeleton (25 - 50 wt%), and nano - level zinc oxide and magnesium oxide raw materials are used as sintering fillers (50 - 75 wt%), forming a cemented structure similar to concrete. This structure can greatly improve the sintering characteristics, avoid the generation of bubbles, and enhance the mechanical strength of the ceramics; finally, the present invention obtains a microwave dielectric ceramic material with a dielectric constant of 21.714, Q×f = 48486.6, and a resonance frequency temperature stability coefficient of - 46.3 ppm / °C, which is expected to be used for manufacturing ceramic substrates with excellent performance; moreover, the microwave dielectric ceramic material prepared by the present invention has stable performance and good consistency, which is conducive to the industrial production of ceramic substrates. Brief Description of the Drawings

[0019] Figure 1 It is the X - ray diffraction pattern of the zinc - magnesium - titanium - based microwave dielectric ceramic in Example 2 of the present invention.

[0020] Figure 2 It is the SEM pattern of the zinc - magnesium - titanium - based microwave dielectric ceramic in Example 2 of the present invention.

[0021] Figure 3 It is the dielectric property diagram of the zinc - magnesium - titanium - based microwave dielectric ceramics in Example 1, Example 2, and the comparative example of the present invention. Detailed Embodiments

[0022] To make the objectives, technical solutions, and beneficial effects of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0023] Example 1

[0024] This example provides a method for growing zinc magnesium titanium-based microwave dielectric ceramics based on the skeleton effect. The chemical formula of the zinc magnesium titanium-based microwave dielectric ceramics is: Zn 0.7 Mg 0.3 TiO3, and specifically includes the following steps:

[0025] a. Using zinc oxide powder, magnesium oxide powder, and titanium dioxide powder as raw materials, weigh and mix zinc oxide powder, magnesium oxide powder, and titanium dioxide powder according to the composition of Zn 0.7 Mg 0.3 TiO3 respectively; among them, each raw material consists of powders with two particle sizes, namely 50wt% of micron-sized (particle size) powders and 50wt% of nano-sized (particle size) powders;

[0026] b. Put the mixed raw materials into a planetary ball mill, and perform wet ball milling with deionized water and anhydrous ethanol as solvents and agate beads as ball milling media. Among them, the mass ratio of the raw materials to the solvents is 1:1.5, the volume ratio of deionized water to anhydrous ethanol in the solvents is 1:1, and the ball milling time is 12 hours; after the ball milling is completed, dry the obtained slurry in an 85°C oven, and grind it to obtain precursor powder;

[0027] c. Calcinate the precursor powder at 850°C for 2 hours to obtain a pre-sintered material;

[0028] d. Perform secondary ball milling on the pre-sintered material. The secondary ball milling uses the same wet ball milling as in step b; after the ball milling is completed, dry the obtained slurry in an 85°C oven, and grind it to obtain Zn 0.7 Mg 0.3 TiO3 powder;

[0029] e. Granulate the Zn 0.7 Mg 0.3 TiO3 powder with polyvinyl alcohol (PVA, 10%) binder and sieve it. The dosage of the binder is 12 ml. The sieving process is as follows: sieve through 40 meshes and 100 meshes in sequence, and take the particles between 40 meshes and 100 meshes; then press the obtained particles at a pressure of 15 Kg / cm 2 for 2 minutes to form a cylindrical green body (Φ×h: 12 mm×6 mm);

[0030] f. Sinter the green body at 1150°C for 4 hours to obtain a zinc magnesium titanium-based microwave dielectric ceramic material.

[0031] The zinc-magnesium-titanium-based microwave dielectric ceramic material prepared in this example was tested. Its dielectric constant was 22.154, Q×f = 31017.6, and the temperature stability coefficient of the resonance frequency was -38.8 ppm / °C.

[0032] Example 2

[0033] This example provides a method for growing zinc-magnesium-titanium-based microwave dielectric ceramics based on the skeleton effect. The chemical expression of the zinc-magnesium-titanium-based microwave dielectric ceramics is: Zn 0.7 Mg 0.3 TiO3. The only difference from Example 1 is that in step a, each raw material consists of powders of two particle sizes, namely 25 wt% of micron-sized (particle size) powders and 75 wt% of nano-sized (particle size) powders.

[0034] The zinc-magnesium-titanium-based microwave dielectric ceramic material prepared in this example was tested. Among them, the X-ray diffraction pattern is as Figure 1 shown. It can be seen from the figure that the microwave dielectric ceramic material Zn 0.7 Mg 0.3 TiO3 has good crystallinity; the SEM pattern is as Figure 2 shown. It can be seen from the figure that the microstructure of the sample shows dense and well-packed grains; in addition, the dielectric constant of the zinc-magnesium-titanium-based microwave dielectric ceramic material is 21.714, Q×f = 48486.6, and the temperature stability coefficient of the resonance frequency is -46.3 ppm / °C.

[0035] Comparative Example

[0036] This comparative example provides a method for growing zinc-magnesium-titanium-based microwave dielectric ceramics based on the skeleton effect. The chemical expression of the zinc-magnesium-titanium-based microwave dielectric ceramics is: Zn 0.7 Mg 0.3 TiO3. The only difference from Example 1 is that in step a, each raw material consists of powders of two particle sizes, namely 75 wt% of micron-sized (particle size) powders and 25 wt% of nano-sized (particle size) powders.

[0037] The dielectric properties of the zinc-magnesium-titanium-based microwave dielectric ceramics in Example 1, Example 2 and the comparative example were compared. The results are as Figure 3 shown. It can be seen from the figure that Example 1 and Example 2 have better dielectric properties because by controlling the particle sizes of the zinc oxide powder, magnesium oxide powder and titanium dioxide powder, a cementitious structure similar to concrete is formed, and this structure can greatly improve the sintering characteristics and avoid the generation of bubbles in the material.

[0038] The above are only specific embodiments of the present invention. Any feature disclosed in this specification, unless specifically described, can be replaced by other equivalent or alternative features with similar purposes; all the disclosed features, or all the steps in any method or process, except for mutually exclusive features and / or steps, can be combined in any manner.

Claims

1. A method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect, characterized in that It includes the following steps: a. Using zinc oxide powder, magnesium oxide powder and titanium dioxide powder as raw materials, according to Zn 0.7 Mg 0.3 TiO3 composition: weigh raw materials respectively and mix them; wherein each raw material is composed of powders of two particle sizes, namely 25-50wt% of micron-grade powder and 50-75wt% of nano-grade powder; b. Conduct primary ball milling on the mixed raw materials. After the ball milling is completed, dry and grind the slurry to obtain the precursor powder; c. Calcinate the precursor powder at 850°C - 950°C for 2 - 4 hours to obtain the pre-calcined material; d. Secondarily ball-mill the presintered material. After the ball milling is completed, dry and grind the slurry to obtain Zn 0.7 Mg 0.3 TiO3 powder; e. Add Zn 0.7 Mg 0.3 Granulate the TiO3 powder with polyvinyl alcohol binder, and compact it into a green body after sieving; f. Sinter the green body at 1150°C - 1200°C for 4 - 6 hours to obtain the zinc magnesium titanium microwave ceramic material.

2. The method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect according to claim 1, characterized in that, In step a, for the three raw materials, the ratio of the micron-sized powder to the nano-sized powder can be the same or different.

3. The method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect according to claim 1, wherein In steps b and d, both the primary ball milling and the secondary ball milling adopt the same wet ball milling method. The wet ball milling is carried out in a planetary ball mill, using deionized water and absolute ethanol as solvents and agate beads as the ball milling medium. Among them, the mass ratio of the raw materials to the solvents is 1:1.5, the volume ratio of deionized water to absolute ethanol in the solvents is 1:1, and the ball milling time is 12 hours.

4. The method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect according to claim 1, characterized in that, In steps b and d, the drying temperature is 85°C and the drying time is 24 hours.

5. The method for growing zinc magnesium titanium microwave ceramics based on the skeleton effect according to claim 1, characterized in that, In step e, the dosage of the binder is 10 - 15 mL; the sieving process is as follows: sieve through 40 mesh and 100 mesh in sequence, and take the particles between 40 mesh and 100 mesh; the pressure for briquetting is 15 - 20 Kg / cm 2 , the time is 2 - 3 minutes, and a cylindrical green body is pressed.

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