Microwave dielectric ceramic material with medium and high dielectric constants and preparation method thereof

A microwave dielectric ceramic and high dielectric constant technology, applied in the field of dielectric ceramic materials, can solve the problems of inability to meet industrial needs, low resonance frequency quality factor, environmental hazards, etc., achieve stable temperature coefficient, good compactness of finished products, easy obtained effect

Active Publication Date: 2015-01-07
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Currently medium and high ε r and high Q f Value microwave dielectric ceramics, mainly include: (1) Ba(Zr, Sn)TiO 4 etc.-based MWDC materials, whose ε r ≈40, f=3~4GHz, Q=(6~9)×10 3 , τ f 1-x ln 2x / 3 TiO 3 (Ln=La, Sm, Nd, etc.), composite perovskite structure CaO-Li 2 O-Ln 2 o 3 -TiO 2 Contour ε r Although microwave dielectric ceramics have a high dielectric constant (>90), but because of their resonant frequency temperature coefficient (>20ppm / ℃) or low quality factor (Q f ~5000GHz) and cannot meet the needs of industry; (3) Although the microwave dielectric properties of lead-based series materials are relatively good, they will cause harm to the environment due to their lead content

Method used

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  • Microwave dielectric ceramic material with medium and high dielectric constants and preparation method thereof
  • Microwave dielectric ceramic material with medium and high dielectric constants and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0036] 1) CaCO 3 、TiO 2 Mix at a molar ratio of 1:1, use absolute ethanol as a solvent, and undergo wet ball milling for 4 hours to obtain sample A;

[0037] CaCO 3 , Nb 2 o 5 , Fe 3 o 4 Mixed at a molar ratio of 50:12.5:8.3, using absolute ethanol as a solvent, and subjected to wet ball milling for 4 hours, to obtain sample B; wherein, CaCO 3 、TiO 2 , Nb 2 o 5 and Fe 3 o 4 The purity is greater than 99%;

[0038] 2) Dry sample A and sample B respectively at 80°C, and then pre-fire in air atmosphere at 1100°C for 2 hours to obtain powder A and powder B;

[0039] 3) The powder A and the powder B were wet ball milled for 5 hours and dried to obtain the dried powder A and the dried powder B, and the dried powder A and the dried powder B were mixed in a molar ratio of 90:10, After wet ball milling for 4 hours, mixed powder C was obtained after drying, and an aqueous polyvinyl alcohol solution with a mass concentration of 1% was added as an organic binder to the mixed ...

Embodiment 2

[0043] 1) CaCO 3 、TiO 2 Mix at a molar ratio of 1:1, use absolute ethanol as a solvent, and undergo wet ball milling for 5 hours to obtain sample A;

[0044] CaCO 3 , Nb 2 o 5 , Fe 3 o 4 Mixed at a molar ratio of 50:12.5:8.3, using absolute ethanol as a solvent, and subjected to wet ball milling for 4 hours, to obtain sample B; wherein, CaCO 3 、TiO 2 , Nb 2 o 5 and Fe 3 o 4 The purity is greater than 99%;

[0045] 2) Dry samples A and B at 90°C respectively, and then pre-fire them in an air atmosphere at 1000°C for 5 hours to obtain powder A and powder B;

[0046] 3) The powder A and the powder B were wet ball milled for 6 hours and dried to obtain the dried powder A and the dried powder B, and the dried powder A and the dried powder B were mixed in a molar ratio of 70:30, After wet ball milling for 4 hours, mixed powder C was obtained after drying, and a polyvinyl alcohol aqueous solution with a mass concentration of 5% was added to the mixed powder C, and granul...

Embodiment 3

[0050] 1) CaCO 3 、TiO 2 Mix at a molar ratio of 1:1, use absolute ethanol as a solvent, and undergo wet ball milling for 6 hours to obtain sample A;

[0051] CaCO 3 , Nb 2 o 5 , Fe 3 o 4 Mixed at a molar ratio of 50:12.5:8.3, using absolute ethanol as a solvent, and subjected to wet ball milling for 5 hours to obtain sample B; wherein, CaCO 3 、TiO 2 , Nb 2 o 5 and Fe 3 o 4 The purity is greater than 99%;

[0052] 2) Dry sample A and sample B at 100°C respectively, and then pre-fire them in an air atmosphere at 980°C for 3 hours to obtain powder A and powder B;

[0053] 3) The powder A and the powder B were wet ball milled for 6 hours and dried to obtain the dried powder A and the dried powder B, and the dried powder A and the dried powder B were mixed in a molar ratio of 50:50, After wet ball milling for 5 hours, mixed powder C was obtained after drying, and a polyvinyl alcohol aqueous solution with a mass concentration of 3% was added to the mixed powder C, granu...

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Abstract

The invention provides a microwave dielectric ceramic material with medium and high dielectric constants and a preparation method thereof. The general chemical formula of the microwave dielectric ceramic material is Ca(Fe,Nb)1-x / 2TixO3. The preparation method comprises the following steps: mixing CaCO3 and TiO2 and carrying out wet ball milling so as to obtain a sample A; mixing CaCO3, Nb2O5 and Fe3O4 and carrying out wet ball milling so as to obtain a sample B; and mixing the sample A and the sample B, carrying out wet ball milling and drying so as to obtain a sample C, adding an aqueous polyvinyl alcohol solution into the sample C, carrying out granulation, sieving, dry pressing and sintering in an air atmosphere. The preparation method provided by the invention is simple, needs a short period and is suitable for mass production; the prepared ceramic material can be used as a microwave dielectric material and has density of more than 97%, the material has a high material quality factor and a stable temperature coefficient while maintaining medium and high dielectric constants, and the microwave dielectric ceramic material has medium and high dielectric constants and a near-zero temperature coefficient of resonant frequency.

Description

technical field [0001] The invention relates to a dielectric ceramic material used in a communication system, in particular to a medium-high dielectric constant microwave dielectric ceramic material and a preparation method thereof. Background technique [0002] With the development of components such as resonators, filters, dielectric substrates, and dielectric waveguide circuits in modern communications, the application of microwave dielectric materials in them is playing an increasingly important role. Microwave dielectric ceramic materials with excellent performance need Satisfy the following conditions: (1) have as high a dielectric constant as possible in the microwave band, which is conducive to the miniaturization of equipment; (2) for non-low dielectric constant materials, the temperature coefficient of resonant frequency is close to zero in the range of - 20ppm / ℃<τ f <20ppm / ℃, for low dielectric constant materials, the range is -10ppm / ℃<τ f <10ppm / ℃, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/462C04B35/26C04B35/495C04B35/622
Inventor 汪宏曾一
Owner XI AN JIAOTONG UNIV
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