阅读说明：本技术 一种谐振频率温度系数近零的微波介质材料 (Microwave dielectric material with near-zero temperature coefficient of resonant frequency ) 是由 李玲霞 乔坚栗 杜明昆 罗伟嘉 彭伟 于 2019-10-14 设计创作，主要内容包括：本发明公开了一种谐振频率温度系数近零的微波介质材料,以TiO<Sub>2</Sub>、ZnO、Nb<Sub>2</Sub>O<Sub>5</Sub>、ZrO<Sub>2</Sub>为原料,目标合成物表达式为(Zr<Sub>1-x</Sub>Ti<Sub>x</Sub>)<Sub>1-y</Sub>(Zn<Sub>1/</Sub><Sub>3</Sub>Nb<Sub>2/3</Sub>)<Sub>y</Sub>O<Sub>2</Sub>,其中x＝0.6～0.7,y＝0.1～0.3。先将原料按化学计量式进行配料,经过球磨、烘干、过筛后于1050℃预烧,再经球磨、烘干后进行造粒,压制成生坯；生坯以5℃/min的速率升温至1250℃,保温30分钟,再以10℃/min的速率降温至1150℃并保温12小时,冷却后制得谐振频率温度系数近零的微波介质材料。本发明的两段式烧结,先使陶瓷生坯加热到较高的温度并短时间保温,再在较低的温度长时间保温,使陶瓷达到较高致密度,同时减小两相间的残余应力,有效改善了两相复合微波介质陶瓷材料Qf值较低的缺点。(The invention discloses a microwave dielectric material with a near-zero resonant frequency temperature coefficient, which is prepared from TiO 2 、ZnO、Nb 2 O 5 、ZrO 2 As a raw material, the expression of the target composition is (Zr) 1‑x Ti x ) 1‑y (Zn 1/ 3 Nb 2/3 ) y O 2 Wherein x is 0.6-0.7, and y is 0.1-0.3. Firstly, raw materials are proportioned according to a stoichiometric formula, are presintered at 1050 ℃ after ball milling, drying and sieving, and are granulated and pressed into green bodies after ball milling and drying; heating the green body to 1250 ℃ at the speed of 5 ℃/min, preserving heat for 30 minutes, cooling to 1150 ℃ at the speed of 10 ℃/min, preserving heat for 12 hours, and cooling to obtain the resonanceThe microwave dielectric material has a frequency temperature coefficient close to zero. The two-stage sintering of the invention firstly heats the ceramic green body to a higher temperature and preserves the temperature for a short time, and then preserves the temperature for a long time at a lower temperature, so that the ceramic achieves higher density, simultaneously reduces the residual stress between two phases, and effectively improves the defect of lower Qf value of the two-phase composite microwave dielectric ceramic material.)

1. A microwave dielectric material with near-zero temperature coefficient of resonance frequency, which is TiO₂、ZnO、Nb₂O₅、ZrO₂As a raw material, the expression of the target composition is (Zr)_1-xTi_x)_1-y(Zn_1/3Nb_2/3)_yO₂Wherein x is 0.6-0.7, and y is 0.1-0.3.

The preparation method of the microwave dielectric material comprises the following implementation steps:

(1) adding TiO into the mixture₂、ZnO、Nb₂O₅、ZrO₂In stoichiometric formula (Zr)_1-xTi_x)_1-y(Zn_1/3Nb_2/3)_yO₂Mixing the powder materials, wherein x is 0.6-0.7 and y is 0.1-0.3Adding deionized water and zirconium balls into a polyester tank, and performing ball milling for 4-8 hours;

(2) putting the ball-milled raw materials in the step (1) into a drying oven, drying at 80-120 ℃ respectively, and then sieving with a 40-mesh sieve;

(3) putting the powder sieved in the step (2) into a medium-temperature furnace, presintering at 1050 ℃, preserving heat for 2-8 hours, and then sieving by a 40-mesh sieve;

(4) putting the powder subjected to the pre-sintering in the step (3) into a ball milling tank, adding zirconia balls and deionized water, and carrying out ball milling for 9-12 hours;

(5) putting the ball-milled raw materials in the step (4) into a drying oven, drying, adding 5% polyvinyl alcohol aqueous solution as an adhesive, granulating, sieving with a 80-mesh sieve, and pressing into a green body by using a powder tablet press at a pressure of 4-8 MPa;

(6) and (3) putting the green body obtained in the step (5) into a medium temperature furnace, heating to 1250 ℃ at the speed of 5 ℃/min, preserving the temperature for 30 minutes, then cooling to 1150 ℃ at the speed of 10 ℃/min, preserving the temperature for 12 hours at 1150 ℃, and then cooling along with the furnace to obtain the microwave dielectric material with the resonant frequency temperature coefficient close to zero.

2. A microwave dielectric material with a resonant frequency temperature coefficient close to zero as claimed in claim 1, wherein said step (1) is performed by ball milling with a planetary ball mill, and the rotation speed of the ball mill is 400 rpm.

3. A microwave dielectric material with a temperature coefficient of resonance frequency close to zero as claimed in claim 1, wherein the green compact of step (5) has a diameter of 10mm and a thickness of 5 mm.

4. A microwave dielectric material with a temperature coefficient of resonance frequency close to zero as claimed in claim 1, wherein said step (6) is sintering in air atmosphere.

Technical Field

The present invention belongs to a ceramic composition characterized by that it is a medium-temp. sintered (Zr) with high dielectric constant and near-zero temp. coefficient of resonance frequency_1-xTi_x)_1-y(Zn_1/3Nb_2/3)_yO₂Wherein x is 0.6-0.7, and y is 0.1-0.3 series microwave dielectric ceramics and its preparation method.

Background

Microwave technology is one of the great achievements of recent scientific development. Because microwaves have the advantages of short wavelength, high frequency and the like, the microwaves have good frequency selection characteristics and are widely applied to the fields of mobile communication, satellite communication, military radar, Global Positioning System (GPS), Bluetooth technology, wireless local area network and the like. The development of microwave communication technology places new demands on the performance (sensitivity, signal-to-noise ratio, coverage, communication capacity, etc.) and size of microwave devices. Driven by this technical background, microwave dielectric ceramic materials with high dielectric constant, low dielectric loss and temperature coefficient of near-zero resonant frequency are urgently needed.

(Zr_1-xTi_x)_1-y(Zn_1/3Nb_2/3)_yO₂The microwave dielectric ceramic is a manganese-tantalum ore-rutile two-phase composite structure, the system has a high dielectric constant (40-50), a near-zero temperature coefficient and a moderate sintering temperature (1200 ℃), but the material system has a low Qf value due to the existence of residual stress between two phases, and further development of the system is limited.

Disclosure of Invention

The purpose of the invention is to overcome (Zr)_1-xTi_x)_1-y(Zn_1/3Nb_2/3)_yO₂The microwave dielectric ceramic has the defect of low Qf value due to the existence of residual stress between two phases. By adopting a two-stage sintering technology, a series of microwave dielectric ceramics with near-zero resonant frequency temperature coefficient and high quality factor are obtained, and (Zr) is provided at the same time_1-xTi_x)_1-y(Zn_1/3Nb_2/3)_yO₂Composition of microwave dielectric ceramicFormulation and process for preparing the dielectric ceramic.

The invention is realized by the following technical scheme.

A microwave dielectric material with near-zero temperature coefficient of resonance frequency, which is TiO₂、ZnO、Nb₂O₅、ZrO₂As a raw material, the expression of the target composition is (Zr)_1-xTi_x)_1-y(Zn_1/3Nb_2/3)_yO₂Wherein x is 0.6-0.7, and y is 0.1-0.3;

the preparation method of the microwave dielectric material comprises the following implementation steps:

(1) adding TiO into the mixture₂、ZnO、Nb₂O₅、ZrO₂In stoichiometric formula (Zr)_1-xTi_x)_1-y(Zn_1/3Nb_2/3)_yO₂Mixing x is 0.6-0.7 and y is 0.1-0.3, putting the powder into a polyester tank, adding deionized water and zirconium balls, and performing ball milling for 4-8 hours;

(2) putting the ball-milled raw materials in the step (1) into a drying oven, drying at 80-120 ℃ respectively, and then sieving with a 40-mesh sieve;

(3) putting the powder sieved in the step (2) into a medium-temperature furnace, presintering at 1050 ℃, preserving heat for 2-8 hours, and then sieving by a 40-mesh sieve;

(4) putting the powder subjected to the pre-sintering in the step (3) into a ball milling tank, adding zirconia balls and deionized water, and carrying out ball milling for 9-12 hours;

(5) putting the ball-milled raw materials in the step (4) into a drying oven, drying, adding 5% polyvinyl alcohol aqueous solution as an adhesive, granulating, sieving with a 80-mesh sieve, and pressing into a green body by using a powder tablet press at a pressure of 4-8 MPa;

(6) and (3) putting the green body obtained in the step (5) into a medium temperature furnace, heating to 1250 ℃ at the speed of 5 ℃/min, preserving the temperature for 30 minutes, then cooling to 1150 ℃ at the speed of 10 ℃/min, preserving the temperature for 12 hours at 1150 ℃, and then cooling along with the furnace to obtain the microwave dielectric material with the resonant frequency temperature coefficient close to zero.

And (2) ball milling is carried out in the step (1) by adopting a planetary ball mill, and the rotating speed of the ball mill is 400 r/min.

The diameter of the green body obtained in the step (5) is 10mm, and the thickness of the green body is 5 mm.

And the step (6) is sintering in an air atmosphere.

The invention provides a series of formula compositions with near-zero temperature coefficient of resonance frequency, which have higher dielectric constant, higher Qf value and lower sintering temperature and can meet the requirements of practical engineering application on microwave dielectric materials. Meanwhile, the invention also provides a novel sintering technology suitable for the two-phase composite microwave dielectric ceramic material: two-stage sintering technique. The two-section sintering is that firstly, the ceramic green body is heated to a higher temperature and is insulated for a short time, so that the green body achieves a proper density; and then the ceramic is kept at a lower temperature for a long time, so that the ceramic can reach higher density, and the residual stress between the two phases is reduced as much as possible. The method effectively overcomes the defect of low Qf value of the two-phase composite microwave dielectric ceramic material.

Detailed Description