CN111943665A - CTLA microwave dielectric material preparation method based on reaction sintering - Google Patents

Abstract

The invention discloses a CTLA microwave dielectric material preparation method based on reaction sintering, which comprises the following steps: CaCO with the purity of more than or equal to 99 percent₃、La₂O₃、Al₂O₃、TiO₂And CeO₂As the main raw material, according to 0.675CaTiO₃‑0.325LaAlO₃+0.5%wtCeO₂Proportioning, mixing the materials by wet ball milling for 4 hours, drying and then pressing the materials by using ethanol as a ball milling medium, and finally sintering the porcelain at 1500-1600 ℃ for 6 hours. The microwave dielectric ceramic prepared by reaction sintering is adopted, the sintering temperature is 1500-1600 ℃, the dielectric constant is moderate (41.1-47.0),Q×fhigh value (25700-47800 GHz), temperature coefficient of resonance frequency (cτ _f ) The method is near zero and simple in process, and can be used for manufacturing microwave devices such as chip resonators, antennas and filters.

Description

CTLA microwave dielectric material preparation method based on reaction sintering

Technical Field

The invention relates to a CTLA microwave dielectric material preparation method based on reaction sintering, belonging to the technical field of CTLA microwave dielectric material preparation.

Background

The microwave dielectric ceramic is a material which is applied to a microwave frequency band circuit as a medium and can complete one or more functions, and is mainly used for preparing microwave components such as a resonator, a filter, a dielectric antenna and the like. The microwave dielectric filter has the advantages of low loss, small frequency temperature coefficient, low cost and the like. Compared with a metal resonant filter, the metal resonant filter has the advantages of miniaturization, and the volume of the metal resonant filter is only one tenth of that of the metal resonant filter; compared with the surface acoustic wave filter, the frequency of the filter is high, and the cost is low. Micro-meterThe wave filter is widely applied to systems such as microwave communication, radar navigation, electronic countermeasure, satellite relay, missile guidance, test instruments and the like, is an indispensable device in microwave and millimeter wave systems, and the performance of the wave filter is often directly influenced by the quality of the performance of the whole communication system. As a key material for microwave dielectric filters, microwave dielectric ceramics must have excellent dielectric properties, such as high quality factor, moderate dielectric constant and near-zero temperature coefficient of resonance frequency. Such as CTLA ceramics, the microwave dielectric property is as follows:_r40-47, Q × f 35000Ghz, and τ f 0 ppm/deg.C. Generally, the solid-phase ceramic process is the most common method for preparing microwave dielectric ceramics, but the preparation process is relatively complicated, so that it is important to explore a preparation method with simpler process.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the preparation method of the CTLA microwave dielectric material based on reaction sintering saves the pre-sintering process of ceramics, has simpler preparation process, and greatly shortens the preparation period of the ceramics, thereby effectively reducing the preparation cost of the ceramics.

The technical scheme adopted by the invention is as follows: a preparation method of a CTLA microwave dielectric material based on reaction sintering comprises the following steps:

s1, mixing the raw material La₂O₃Putting the raw materials into a crucible for presintering, raising the temperature of the raw materials from room temperature to 900 ℃ at the temperature raising rate of 5 ℃/min, and preserving the heat for 2 hours at the temperature;

s2 CaCO with purity more than or equal to 99%₃、Al₂O₃、TiO₂、CeO₂And La obtained in step (1)₂O₃As the main raw material, according to 0.675CaTiO₃-0.325LaAlO₃(CTLA) + 0.5% wtCeO₂Weighing the components according to the mass ratio, and then mixing the materials; according to the mass ratio of the absolute ethyl alcohol to the powder of 1: 1, adding absolute ethyl alcohol into the powder, and mixing for 4 hours by a wet grinding method;

and S3, drying the mixture at 120-140 ℃, sieving the mixture by using a 80-mesh sieve, pressing the sieved fine powder mixture into a small cylinder with the diameter of 7mm and the thickness of 6mm under the pressure of 10MPa, and sintering the small cylinder at 1500-1600 ℃ for 6 hours to obtain the required microwave dielectric ceramic material.

The invention has the beneficial effects that: compared with the prior art, the microwave dielectric ceramic prepared by the invention uses factory-level raw materials, adopts reaction sintering, and has simple sintering process and excellent microwave performance: the dielectric constant is moderate (41.1-47.0), the Qxf value is high and reaches 47800GHz, compared with the existing 35000Ghz, the dielectric constant is improved by about 37%, and the temperature coefficient (tau) of the resonant frequency is increased_f) The method is near zero, and can be used for manufacturing microwave devices such as chip resonators, microwave antennas, filters and the like, and removing moisture and carbon dioxide by pre-burning reactants.

Detailed Description

The invention is further described below with reference to specific examples.

Example 1: a preparation method of a CTLA microwave dielectric material based on reaction sintering comprises the following steps:

s1, mixing the raw material La₂O₃Putting the raw materials into a crucible for presintering, raising the temperature of the raw materials from room temperature to 900 ℃ at the temperature raising rate of 5 ℃/min, and preserving the heat for 2 hours at the temperature; removing water and carbon dioxide;

s2 CaCO with purity more than or equal to 99%₃、Al₂O₃、TiO₂、CeO₂And La obtained in step (1)₂O₃As the main raw material, according to 0.675CaTiO₃-0.325LaAlO₃(CTLA) + 0.5% wtCeO₂Weighing the components according to the mass ratio, and then mixing the materials; according to the mass ratio of the absolute ethyl alcohol to the powder of 1: 1, adding absolute ethyl alcohol into the powder, and mixing for 4 hours by a wet grinding method;

and S3, drying the mixture at 120-140 ℃, sieving the mixture by using a 80-mesh sieve, pressing the sieved fine powder mixture into a small cylinder with the diameter of 7mm and the thickness of 6mm under the pressure of 10MPa, and sintering the small cylinder at 1500-1600 ℃ for 6 hours to obtain the required microwave dielectric ceramic material.

Table 1 lists the microwave dielectric properties of samples prepared by the method with different proportions of components and different sintering temperatures. The preparation method is as described above, and the evaluation of the microwave dielectric property is carried out by the cylindrical dielectric resonator method.

The method uses factory-level raw materials and adopts reaction sintering for preparation, thereby greatly reducing the production cost of the microwave device; by simultaneous doping with CeO₂Improve the dielectric property of CTLA ceramic.

Table 1:

composition of	Sintering temperature (. degree. C.)	εr	Q×fGHz)	τf(ppm/℃)
					0.67CT-0.33LA	1500	44.1	24900	4.85
0.67CT-0.33LA	1525	42.9	30400	2.8
					0.67CT-0.33LA	1550	35.9	41700	1.83
0.67CT-0.33LA	1575	41.3	25700	1.395
					0.67CT-0.33LA	1600	41.1	35300	1.09
0.675CT-0.325LA	1500	42.1	34400	6.92
					0.675CT-0.325LA	1525	41.3	45400	3.02
0.675CT-0.325LA	1550	45.3	41500	4.7
					0.675CT-0.325LA	1575	45.6	47800	3.7
0.675CT-0.325LA	1600	47.0	45400	3.9

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present invention, and therefore, the scope of the present invention should be determined by the scope of the claims.

Claims (1)

1. A preparation method of CTLA microwave dielectric material based on reaction sintering is characterized in that: the method comprises the following steps:

s1, mixing the raw material La₂O₃Putting the raw materials into a crucible for presintering, raising the temperature of the raw materials from room temperature to 900 ℃ at the temperature raising rate of 5 ℃/min, and preserving the heat for 2 hours at the temperature;

s2 CaCO with purity more than or equal to 99%₃、Al₂O₃、TiO₂、CeO₂And La obtained in step (1)₂O₃As the main raw material, according to 0.675CaTiO₃-0.325LaAlO₃+0.5%wtCeO₂Weighing the components according to the mass ratio, and then mixing the materials; according to the mass ratio of the absolute ethyl alcohol to the powder of 1: 1, adding absolute ethyl alcohol into the powder, and mixing for 4 hours by a wet grinding method;

and S3, drying the mixture at 120-140 ℃, sieving the mixture by using a 80-mesh sieve, pressing the sieved fine powder mixture into a small cylinder with the diameter of 7mm and the thickness of 6mm under the pressure of 10MPa, and sintering the small cylinder at 1500-1600 ℃ for 6 hours to obtain the required microwave dielectric ceramic material.