阅读说明：本技术 一种微波介质陶瓷材料及其制备方法 (Microwave dielectric ceramic material and preparation method thereof ) 是由 周晓华 彭昶 张树人 于 2020-04-03 设计创作，主要内容包括：一种微波介质陶瓷材料及其制备方法,属于电子陶瓷材料技术领域。所述陶瓷材料各组分的质量百分比为：MgO为10～16wt％、Al<Sub>2</Sub>O<Sub>3</Sub>为25～35wt％、SiO<Sub>2</Sub>为45～55wt％、TiO<Sub>2</Sub>为1～10wt％、ZrO<Sub>2</Sub>为0～5wt％、CoO为1～5wt％。本发明工艺简单,原材料成本低,兼具低介电常数、高品质因数、低频率温度系数的优异性能。本发明微波介质陶瓷材料,其介电常数为4～6,品质因数Q×f值为45000～70000GHz,频率温度系数小于±15ppm/℃,烧结温度为1300～1380℃。(A microwave dielectric ceramic material and a preparation method thereof belong to the technical field of electronic ceramic materials. The ceramic material comprises the following components in percentage by mass: 10 to 16 wt% of MgO and Al 2 O 3 25 to 35 wt% of SiO 2 45 to 55 wt% of TiO 2 1 to 10 wt% of ZrO 2 The dielectric constant of the microwave dielectric ceramic material is 4-6, the quality factor Q × f value is 45000-70000 GHz, the frequency temperature coefficient is less than +/-15 ppm/DEG C, and the sintering temperature is 1300-1380 ℃.)

1. The microwave dielectric ceramic material is characterized by comprising the following components in percentage by mass: 10 to 16 wt% of MgO and Al₂O₃25 to 35 wt% of SiO₂45 to 55 wt% of TiO₂1 to 10 wt% of ZrO₂0 to 5 wt% and CoO 1 to 5 wt%.

2. The preparation method of the microwave dielectric ceramic material is characterized by comprising the following steps of:

step 1, using MgO and Al₂O₃、SiO₂Weighing and mixing the raw materials;

step 2, ball-milling the powder obtained in the step 1 for 5-8 hours, drying and sieving to obtain dry powder;

step 3, placing the powder obtained in the step 2 in a crucible, and pre-burning for 1.5-3 hours at the temperature of 1100-1200 ℃ to obtain a pre-burnt material;

step 4, adding TiO into the pre-sintering material obtained in the step 3₂、ZrO₂Ball milling for 5-8 hours by using CoO, and drying; wherein the mass percentages of the components are as follows: 10 to 16 wt% of MgO and Al₂O₃25 to 35 wt% of SiO₂45 to 55 wt% of TiO₂1 to 10 wt% of ZrO₂0 to 5 wt% of CoO, 1 to 5 wt% of CoO;

and 5, granulating and molding the powder dried in the step 4, and sintering the obtained blank at 1300-1380 ℃ for 2-3 hours to obtain the cordierite microwave dielectric ceramic material.

Technical Field

The invention belongs to the technical field of electronic ceramic materials, and particularly relates to a microwave dielectric ceramic material and a preparation method thereof.

Background

In recent years, mobile devices have been developed in an integrated, miniaturized, and low power consumption direction, and communication technologies such as 5G communication and wireless lan have been rapidly developed. Microwave circuits in communication technology often include electronic components such as resonators, filters, dielectric antennas, integrated substrates, etc., and the base materials of these electronic components are microwave dielectric ceramics. The microwave dielectric ceramic meets the development requirements of miniaturization and low power consumption of a communication technology and plays an important role in the field of communication.

Low dielectric microwave ceramic materials have a wide range of applications in communications technology, with lower dielectric constants leading to shorter signal transmission times. The microwave dielectric ceramic material of the silicate system has an extremely low dielectric constant, can greatly increase the transmission efficiency of signals, but the Q multiplied by f value of the microwave dielectric ceramic material is generally low. Wherein the forsterite with the highest Q multiplied by f value reaches 200000GHz, but the temperature coefficient of the frequency is too high as minus 60 ppm/DEG C, and the forsterite is greatly influenced by the temperature and is difficult to apply in practical application. Cordierite has a low dielectric constant of 4.0-6.0, a frequency temperature coefficient of-32 ppm/DEG C lower than that of forsterite, but has the defects of low Q x f value of only 35000GHz, high sintering temperature of 1450 ℃ and the like.

Journal of Alloys and company ceramics 689(2016)81-86 report that calcium titanate is used for doping modification in cordierite ceramic materials, the performance of the cordierite ceramic materials is improved to a certain extent, the dielectric constant is 7.2, the Q × f value is 55490GHz, the temperature coefficient of resonant frequency is-28.3 ppm/DEG C, the Q × f value and the temperature coefficient of resonant frequency are improved, but the temperature coefficient of resonant frequency is not greatly improved, and the materials are greatly influenced by temperature in actual application, and the Sr is adopted by Songhui et al in 2012, on volume 6 of the 27 th report of inorganic materials²⁺Doped replacement of Mg²⁺The cordierite ceramic is prepared by sintering through a solid-phase reaction method, the dielectric constant of the microwave ceramic material is 6.0-7.5, but the Q × f value is 40000GHz, the requirement of a low-loss device cannot be met, and Chinese patent application No. 201410519765.6 discloses that TiO is added₂The microwave dielectric property of the ceramic is improved by adjusting the frequency temperature coefficient of the cordierite ceramic, wherein the dielectric constant is 6.0-8.0, the temperature coefficient of the resonance frequency is-0.2 ppm/DEG C, the Q × f value is 37800GHz, and the requirement of low loss is difficult to meet, and the Chinese patent with the application number of 201810506958.6 discloses that Cr is added₂O₃、ZrO₂The additives can effectively reduce the thermal expansion coefficient and the bending strength, but the dielectric loss is high, the main application field is packaging materials, and the additives are not suitable for low-loss devices such as filters.

Disclosure of Invention

The invention aims to provide a microwave dielectric ceramic material with high quality factor and stable resonant frequency temperature coefficient and a preparation method thereof, aiming at the problems of low quality factor and high frequency temperature coefficient of the existing low-dielectric microwave ceramic material in the background art.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the microwave dielectric ceramic material is characterized by comprising the following components in percentage by mass: 10 to 16 wt% of MgO and Al₂O₃25 to 35 wt% of SiO₂45 to 55 wt% of TiO₂1 to 10 wt% of ZrO₂0 to 5 wt% and CoO 1 to 5 wt%.

The preparation method of the microwave dielectric ceramic material is characterized by comprising the following steps of:

step 1, batching: with MgO, Al₂O₃、SiO₂Weighing and mixing the raw materials;

step 2, ball milling: ball-milling the powder obtained in the step 1 for 5-8 hours to obtain a ball grinding material;

and step 3, drying: drying the ball-milled material obtained in the step 2 and sieving the dried ball-milled material with a 60-mesh sieve to obtain dried powder;

step 4, pre-burning: placing the powder obtained in the step 3 in a crucible, and pre-burning for 1.5-3 hours at the temperature of 1100-1200 ℃ to obtain a pre-burnt material;

and 5, doping: adding TiO into the pre-sintering material obtained in the step 4₂、ZrO₂Ball milling for 5-8 hours by using CoO, and drying; wherein the raw materials and the additives comprise the following components in percentage by mass: 10 to 16 wt% of MgO and Al₂O₃25 to 35 wt% of SiO₂45 to 55 wt% of TiO₂1 to 10 wt% of ZrO₂0 to 5 wt% of CoO, 1 to 5 wt% of CoO;

step 6, granulation and molding: adding PVA into the powder dried in the step 5 for granulation, and performing compression molding under the pressure of 20 MPa-30 MPa;

and 7, sintering: and (4) sintering the blank formed in the step (6) at 1300-1380 ℃ for 2-3 hours to obtain the cordierite microwave dielectric ceramic material.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a microwave dielectric ceramic material and a preparation method thereof, which have the advantages of simple process, low raw material cost, and excellent performances of low dielectric constant, high quality factor and low frequency temperature coefficient. The microwave dielectric ceramic material has a dielectric constant of 4-6, a quality factor Qxf value of 45000-70000 GHz, a frequency temperature coefficient of less than +/-15 ppm/DEG C, and a sintering temperature of 1300-1380 ℃.

Drawings

FIG. 1 is an XRD spectrum of a cordierite microwave dielectric ceramic material prepared in example 3 of the present invention;

FIG. 2 is an XRD spectrum of a cordierite microwave dielectric ceramic material prepared in example 5 of the present invention;

FIG. 3 is an SEM image of a cordierite microwave dielectric ceramic material prepared in example 3 of the present invention;

FIG. 4 is an SEM image of a cordierite microwave dielectric ceramic material prepared in example 5 of the present invention.

Detailed Description

The technical scheme of the invention is detailed below by combining the accompanying drawings and the embodiment.