阅读说明：本技术 一种高介电常数微波介质陶瓷材料 (High-dielectric-constant microwave dielectric ceramic material ) 是由 彭仕强 王秀红 黄庆焕 叶荣 于 2021-07-26 设计创作，主要内容包括：本发明提供了一种高介电常数微波介质陶瓷材料,包括质量百分比为91％～97％的基体材料和质量百分比为3％～9％的改性添加剂；所述基体材料的组成表达式为Ba-(6-3x)R-(8+2x)Ti-(18)O-(54),其中,0.1≤x≤1,R选自Nd和Sm中的一种或两种；所述改性添加剂包括第一添加剂和第二添加剂,所述第一添加剂选自MgO、SiO-(2)和CaCO-(3)中的至少一种,所述第二添加剂选自Al-(2)O-(3)和MnCO-(3)中的一种或两种。还提供了一种高介电常数微波介质陶瓷材料的制备方法。本发明提供的微波介质陶瓷材料具有介电可调的高介电常数、高品质因数、近零范围内可调的谐振频率温度系数、高抗热震性的优异性能。并且,本发明提供的微波介质陶瓷材料的制备方法具有制备方法简便,易于批量生产的特点。(The invention provides a high-dielectric-constant microwave dielectric ceramic material, which comprises 91-97% of a base material and 3-9% of a modified additive by mass percent; the composition expression of the base material is Ba 6‑3x R 8+2x Ti 18 O 54 Wherein x is more than or equal to 0.1 and less than or equal to 1, and R is selected from one or two of Nd and Sm; the modifying additive comprises a first additive and a second additive, wherein the first additive is selected from MgO and SiO 2 And CaCO 3 At least one of, the second additive is selected from Al 2 O 3 And MnCO 3 One or two of them. Also provides a preparation method of the microwave dielectric ceramic material with high dielectric constant. The microwave dielectric ceramic material provided by the invention has the advantages of adjustable dielectric constant, high quality factor and high approximationAdjustable resonance frequency temperature coefficient in a zero range and high thermal shock resistance. In addition, the preparation method of the microwave dielectric ceramic material provided by the invention has the characteristics of simple preparation method and easiness in batch production.)

1. The microwave dielectric ceramic material with high dielectric constant is characterized by comprising 91-97% by mass of a base material and 3-9% by mass of a modified additive; the composition expression of the base material is Ba_6-3xR_{8+ 2x}Ti₁₈O₅₄Wherein x is more than or equal to 0.1 and less than or equal to 1, and R is selected from one or two of Nd and Sm; the modifying additive comprises a first additive and a second additive, wherein the first additive is selected from MgO and SiO₂And CaCO₃At least one of, the second additive is selected from Al₂O₃And MnCO₃One or two of them.

2. A microwave dielectric ceramic material according to claim 1, wherein R is selected from one or two of Nd and Sm, and is further doped with at least one of La, Eu, Bi and Sb.

3. A microwave dielectric ceramic material as claimed in claim 1, wherein the mass percentage of the first additive is 2-7%, and the mass percentage of the second additive is 0.1-2% based on the total mass of the microwave dielectric ceramic material.

4. A microwave dielectric ceramic material according to any one of claims 1-3, wherein the first additive is selected from MgO, SiO based on the total mass of the microwave dielectric ceramic material₂And CaCO₃In the two cases, the mass percent of MgO is 1.0-3.5%, and SiO₂1.0-3.5 percent of CaCO₃The mass percentage of the component (A) is 1.0-4.0%; when the first additive comprises MgO and SiO₂And CaCO₃In the formula, the mass percent of MgO is 0.1-2.0%, and SiO is₂0.05-2.0 percent of CaCO₃The mass percentage of the component (A) is 0.1-3.0%.

5. A microwave dielectric ceramic material according to any one of claims 1-3, wherein when the second additive comprises Al, based on the total mass of the microwave dielectric ceramic material₂O₃And MnCO₃Of (i) is Al₂O₃0.05 to 1.5 percent of MnCO₃The mass percentage of the component (A) is 0.05-0.5%.

6. A method for preparing a high dielectric constant microwave dielectric ceramic material as claimed in any one of claims 1 to 5, comprising:

mixing materials: the base material Ba_6-3xR_8+2xTi₁₈O₅₄Placing the mixture with the modifying additive in a ball mill for wet ball milling to obtain first mixed slurry;

and (3) granulation: adding a binder into the first mixed slurry, fully ball-milling and mixing, and then carrying out spray granulation to obtain granulated powder;

and (3) sintering: and carrying out dry pressing on the granulated powder to prepare a green body, and sintering the green body in a high-temperature furnace to obtain the microwave dielectric ceramic material.

7. A method for preparing microwave dielectric ceramic material according to claim 6, wherein the base material Ba is selected from Ba, P_{6- 3x}R_8+2xTi₁₈O₅₄The reactant feedstock comprises BaCO₃、R₂O₃And TiO₂(ii) a Wherein, BaCO₃10-20% of TiO₂Is 35 to 55 percent, R₂O₃Is 25 to 55 percent, R₂O₃Selected from Nd₂O₃And Sm₂O₃One or two of them.

8. A method for preparing microwave dielectric ceramic material according to claim 7, wherein the reactant raw material of the base material further comprises La₂O₃、Eu₂O₃、Bi₂O₃And Sb₂O₃At least one of (1).

9. A method for preparing a microwave dielectric ceramic material as claimed in claim 8, wherein Nd is based on the total mass of the base material₂O₃0 to 40 percent of Sm₂O₃Is 0 to 40 percent of La₂O₃0 to 10 percent of Eu, Eu₂O₃0 to 10 percent of Bi₂O₃0 to 10 percent of Sb₂O₃The mass percentage of the component (A) is 0-2.0%.

10. Microwaves according to any of claims 6 to 9The preparation method of the dielectric ceramic material is characterized by further comprising a base material Ba_6-3xR_8+2xTi₁₈O₅₄The preparation of (1) comprises:

preparing materials: placing the mixture of the reactant raw materials of the base material in a ball mill for wet ball milling to obtain a second mixed slurry;

pre-burning: drying and sieving the second mixed slurry, and then placing the second mixed slurry in a high-temperature furnace for presintering to obtain the base material Ba_6-3xR_8+2xTi₁₈O₅₄。

Technical Field

The invention belongs to the technical field of microwave dielectric ceramics, and particularly relates to a high-dielectric-constant microwave dielectric ceramic material and a preparation method thereof.

Background

Since the 21 st century, the development of communication technology is changing day by day, the updating is rapid, the transmission rate of communication is faster, the transmission quality is higher, the time delay is lower, the communication is gradually sent to the direction of the interconnection of everything, and the requirements of high frequency, miniaturization and temperature stability are provided for antennas and radio frequency devices. Therefore, the performance requirements of microwave dielectric ceramic materials with high dielectric constants will become higher and higher in the future, and therefore, it is urgently needed to develop a microwave dielectric ceramic material with high dielectric constant, adjustable dielectric, high quality factor, and temperature coefficient of near-zero resonant frequency.

BaO-Ln₂O₃-TiO₂(Ln represents a part of rare earth elements) is the most typical one of high-dielectric-constant microwave dielectric ceramic materials, wherein Ba represents_6-3xLn_8+2xTi₁₈O₅₄(Ln is usually La, Sm, Nd, etc.) is the most representative. Ba_6-3xSm_8+2xTi₁₈O₅₄And Ba_6-3xNd_8+2xTi₁₈O₅₄The dielectric property of the ceramic material is optimal, but the temperature coefficient of the resonant frequency deviates from near zero point, the thermal shock resistance is poor, and the ceramic body is easy to have a 'black core' problem in the high-temperature sintering process, thereby greatly limiting the application of the microwave dielectric ceramic material system.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a high-dielectric-constant microwave dielectric ceramic material with high quality factor, near-zero resonant frequency temperature coefficient, high thermal shock resistance and adjustable dielectric and a preparation method thereof.

According to the high dielectric constant microwave dielectric ceramic material provided by one aspect of the embodiment of the invention, the ceramic material comprises 91-97% by mass of a base material and 3-9% by mass of a modifying additive; the composition expression of the base material is Ba_6-3xR_8+2xTi₁₈O₅₄Wherein x is more than or equal to 0.1 and less than or equal to 1, R is selected from NOne or two of d (neodymium) and Sm (samarium); the modifying additive comprises a first additive and a second additive, wherein the first additive is selected from MgO and SiO₂And CaCO₃At least one of, the second additive is selected from Al₂O₃And MnCO₃One or two of them.

In one example of the high dielectric constant microwave dielectric ceramic material provided in the above aspect, R is selected from one or two of Nd (neodymium) and Sm (samarium), and the R is further doped with at least one of La (lanthanum), Eu (europium), Bi (bismuth), and Sb (antimony).

In an example of the high dielectric constant microwave dielectric ceramic material provided in the above aspect, the mass percentage of the first additive is 2% to 7% and the mass percentage of the second additive is 0.1% to 2% based on the total mass of the microwave dielectric ceramic material.

In an example of the high dielectric constant microwave dielectric ceramic material provided in the above aspect, when the first additive is selected from MgO and SiO based on the total mass of the microwave dielectric ceramic material₂And CaCO₃In the two cases, the mass percent of MgO is 1.0-3.5%, and SiO₂1.0-3.5 percent of CaCO₃The mass percentage of the component (A) is 1.0-4.0%; when the first additive comprises MgO and SiO₂And CaCO₃In the formula, the mass percent of MgO is 0.1-2.0%, and SiO is₂0.05-2.0 percent of CaCO₃The mass percentage of the component (A) is 0.1-3.0%.

In one example of the high-permittivity microwave dielectric ceramic material provided in the above aspect, when the second additive includes Al based on the total mass of the microwave dielectric ceramic material₂O₃And MnCO₃Of (i) is Al₂O₃0.05 to 1.5 percent of MnCO₃The mass percentage of the component (A) is 0.05-0.5%.

According to another aspect of the embodiments of the present invention, there is provided a method for preparing a high dielectric constant microwave dielectric ceramic material, the method comprising the steps of:

mixing materials: the base material Ba_6-3xR_8+2xTi₁₈O₅₄Placing the mixture with the modifying additive in a ball mill for wet ball milling to obtain first mixed slurry;

and (3) granulation: adding a binder into the first mixed slurry, fully ball-milling and mixing, and then carrying out spray granulation to obtain granulated powder;

and (3) sintering: and carrying out dry pressing on the granulated powder to prepare a green body, and sintering the green body in a high-temperature furnace to obtain the microwave dielectric ceramic material.

In an example of the method for preparing the high-dielectric-constant microwave dielectric ceramic material provided by another aspect, the base material Ba_6-3xR_8+2xTi₁₈O₅₄The reactant feedstock comprises BaCO₃、R₂O₃And TiO₂(ii) a Wherein, BaCO₃10-20% of TiO₂Is 35 to 55 percent, R₂O₃Is 25 to 55 percent, R₂O₃Selected from Nd₂O₃(Neodymium oxide) and Sm₂O₃One or two of (samarium oxide).

In an example of the method for preparing the high-dielectric-constant microwave dielectric ceramic material provided by another aspect, the reactant raw material of the base material further includes La₂O₃(lanthanum oxide), Eu₂O₃(europium oxide) and Bi₂O₃(bismuth oxide) and Sb₂O₃At least one of (antimony oxide).

In one example of the method for preparing the high-dielectric-constant microwave dielectric ceramic material provided in the another aspect, Nd is based on the total mass of the base material₂O₃0 to 40 percent of Sm₂O₃Is 0 to 40 percent of La₂O₃0 to 10 percent of Eu, Eu₂O₃0 to 10 percent of Bi₂O₃The mass percentage of the component (A) is 0-10%,Sb₂O₃the mass percentage of the component (A) is 0-2.0%.

In one example of the preparation method of the high-dielectric-constant microwave dielectric ceramic material provided in another aspect, the preparation method further includes a base material Ba_6-3xR_8+2xTi₁₈O₅₄The preparation of (1) comprises:

preparing materials: placing the mixture of the reactant raw materials of the base material in a ball mill for wet ball milling to obtain a second mixed slurry;

pre-burning: drying and sieving the second mixed slurry, and then placing the second mixed slurry in a high-temperature furnace for presintering to obtain the base material Ba_6-3xR_8+2xTi₁₈O₅₄。

Has the advantages that: the high-dielectric-constant microwave dielectric ceramic material provided by the embodiment of the invention comprises a base material Ba_6-3xR_8+2xTi₁₈O₅₄And a modifying additive, by regulating and controlling the base material Ba_6-3xR_8+2xTi₁₈O₅₄The value of x, the element represented by R and the content of the element can be expanded to Ba_6-3xR_8+2xTi₁₈O₅₄The dielectric constant of the ceramic material can be adjusted, and the problem of low electrical property caused by Ti reduction of the ceramic material in the high-temperature sintering process is solved by introducing the modified additive, so that the performance of the material is further improved. Therefore, the microwave dielectric ceramic material prepared by the invention has excellent properties: high dielectric constant (epsilon) with adjustable dielectric_r62.4 to 97.8) and high quality factor (Q)_f5729 GHz-16392 GHz), and a temperature coefficient of resonance frequency (τ) adjustable in a near-zero range_f10 ppm/DEG C to 10 ppm/DEG C) and high thermal shock resistance (delta T to 210 ℃), and can be suitable for the application of a plurality of devices and the use requirement of the transregional climate environment of the devices. In addition, the preparation method of the microwave dielectric ceramic material with the high dielectric constant provided by the embodiment of the invention has the characteristics of simple process and easiness in batch production.

Drawings

The above and other aspects, features and advantages of embodiments of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a flow chart of a method for preparing a high dielectric constant microwave dielectric ceramic material according to an embodiment of the present invention;

FIG. 2 shows a Ba base material provided in example 1 of the present invention_5.7Sm_8.2Ti₁₈O₅₄X-ray diffraction patterns of (a);

fig. 3 is a scanning electron microscope photograph of a microwave dielectric ceramic material provided in accordance with example 5 of the present invention.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided to explain the principles of the invention and its practical application to thereby enable others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated.

As used herein, the term "include" and its variants mean open-ended terms in the sense of "including, but not limited to. The terms "based on," based on, "and the like mean" based at least in part on, "" based at least in part on. The terms "one embodiment" and "an embodiment" mean "at least one embodiment". The term "another embodiment" means "at least one other embodiment". The terms "first," "second," and the like may refer to different or the same object. Other definitions, whether explicit or implicit, may be included below. The definition of a term is consistent throughout the specification unless the context clearly dictates otherwise.

As described in the background section, BaO-Ln prepared by the prior art₂O₃-TiO₂The high dielectric constant microwave dielectric ceramic material system has the problems of over negative temperature coefficient of resonant frequency, poor thermal stability and low electrical property caused by Ti reduction easily in the high-temperature sintering process, so the invention provides a microwave dielectric ceramic material systemA high-dielectric constant microwave dielectric ceramic material with high quality factor, near-zero resonant frequency temperature coefficient and adjustable dielectric and a preparation method thereof. The microwave dielectric ceramic material comprises 91-97% of base material and 3-9% of modified additive by mass percent; the composition expression of the base material is Ba_6-3xR_8+2xTi₁₈O₅₄Wherein x is more than or equal to 0.1 and less than or equal to 1, and R is selected from one or two of Nd and Sm; the modifying additive comprises a first additive and a second additive, wherein the first additive is selected from MgO and SiO₂And CaCO₃At least one of, the second additive is selected from Al₂O₃And MnCO₃One or two of them.

In one example, R is selected from one or two of Nd and Sm, and the R is further doped with at least one of La, Eu, Bi, and Sb.

In one example, the mass percentage of the first additive is 2-7% and the mass percentage of the second additive is 0.1-2% of the total mass of the microwave dielectric ceramic material.

The high dielectric constant microwave dielectric ceramic material as described above: firstly, by regulating and controlling the base material Ba_6-3xR_{8+ 2x}Ti₁₈O₅₄The value of x, the element represented by R and the content of the element can be expanded to Ba_6-3xR_8+2xTi₁₈O₅₄The adjustable range of the dielectric constant of the base ceramic material; secondly, by introducing a small amount of first additives MgO and SiO with negative temperature coefficient of resonance frequency₂And a first additive CaCO of positive resonant frequency temperature coefficient₃May be such that Ba_6-3xR_8+2xTi₁₈O₅₄The temperature coefficient regulation and control of the resonant frequency of the base ceramic material is more stable to be close to zero; finally, by introducing a second additive Al₂O₃And MnCO₃One or two of the components can inhibit the reduction of Ti in the high-temperature sintering process, thereby solving the problem of 'black core' easily appearing in the sintering process of the ceramic material and being beneficial to stabilizing the electrical property of the ceramic material.

In one example, the first additive is selected from MgO and SiO based on the total mass of the microwave dielectric ceramic material₂And CaCO₃In the two cases, the mass percent of MgO is 1.0-3.5%, and SiO₂1.0-3.5 percent of CaCO₃The mass percentage of the component (A) is 1.0-4.0%.

In one example, when the first additive comprises MgO, SiO₂And CaCO₃In the formula, the mass percent of MgO is 0.1-2.0%, and SiO is₂0.05-2.0 percent of CaCO₃The mass percentage of the component (A) is 0.1-3.0%.

In one example, when the second additive comprises Al, based on the total mass of the microwave dielectric ceramic material₂O₃And MnCO₃Of (i) is Al₂O₃0.05 to 1.5 percent of MnCO₃The mass percentage of the component (A) is 0.05-0.5%.

Therefore, based on the above-mentioned Ba_6-3xR_8+2xTi₁₈O₅₄The base microwave dielectric ceramic material has the following excellent properties: high dielectric constant (epsilon) with adjustable dielectric_r62.4 to 97.8) and high quality factor (Q)_f5729 GHz-16392 GHz), and a temperature coefficient of resonance frequency (τ) adjustable in a near-zero range_f10ppm/° c-10 ppm/° c) and high thermal shock resistance (Δ T-210 ℃).

The method for preparing the high dielectric constant microwave dielectric ceramic material according to the embodiment of the invention will be described in detail with reference to the attached drawings.

FIG. 1 is a flow chart of a method for preparing a high dielectric constant microwave dielectric ceramic material according to an embodiment of the present invention.

Referring to fig. 1, the method for preparing a high dielectric constant microwave dielectric ceramic material according to an embodiment of the present invention includes the steps of:

step S10, mixing materials: the base material Ba_6-3xR_8+2xTi₁₈O₅₄The mixture with the modifying additive is placed in a ball mill for wet ball milling to obtain a first mixed slurry.

In one example, the mass percentage of the base material is 91-97% and the mass percentage of the modifying additive is 3-9% based on the total mass of the microwave dielectric ceramic material.

In one example, the wet ball milling is carried out, wherein a ball milling medium is formed by mixing zirconia balls with the diameters of 3mm, 5mm and 8mm according to a mass ratio of 1: 1: 1, wherein the mass ratio of a mixture of a base material and a modified additive, a ball-milling medium and deionized water is 1: (2-5): (4-7), and the time of wet ball milling is 6-12 h.

Wherein the base material Ba_6-3xR_8+2xTi₁₈O₅₄The preparation method specifically comprises the following steps:

step S101, batching: and placing the mixture of the reactant raw materials of the matrix material into a ball mill for wet ball milling to obtain a second mixed slurry.

In one example, the base material Ba_6-3xR_8+2xTi₁₈O₅₄The reactant feedstock comprises BaCO₃、R₂O₃And TiO₂(ii) a Wherein, BaCO₃10-20% of TiO₂Is 35 to 55 percent, R₂O₃Is 25 to 55 percent, R₂O₃Selected from Nd₂O₃And Sm₂O₃One or two of them.

In one example, the reactant feedstock for the matrix material further comprises La₂O₃、Eu₂O₃、Bi₂O₃And Sb₂O₃At least one of (1).

In one example, Nd is present based on the total mass of the matrix material₂O₃0 to 40 percent of Sm₂O₃Is 0 to 40 percent of La₂O₃0 to 10 percent of Eu, Eu₂O₃0 to 10 percent of Bi₂O₃0 to 10 percent of Sb₂O₃The mass percentage of the component (A) is 0-2.0%.

In one example, the wet ball milling is carried out, wherein a ball milling medium is formed by mixing zirconia balls with the diameters of 3mm, 5mm and 8mm according to a mass ratio of 1: 1: 1, wherein the mass ratio of a reactant raw material mixture of the matrix material, a ball-milling medium and deionized water is 1: (2-5): (4-7), and the time of wet ball milling is 6-12 h.

Step S102, burn-in: drying and sieving the second mixed slurry, and then placing the second mixed slurry in a high-temperature furnace for presintering to obtain the base material Ba_6-3xR_8+2xTi₁₈O₅₄。

In one example, the second mixed slurry has a drying temperature of 70 ℃ to 120 ℃; the screen mesh is 200 meshes in the screening treatment; the pre-sintering temperature is 950-1150 ℃, and the pre-sintering time is 2-4 h.

Step S20, granulation: and adding a binder into the first mixed slurry, continuing wet ball milling, and performing spray granulation after full mixing to obtain granulated powder.

In one example, the binder is an aqueous solution of polyvinyl alcohol; the concentration of the binder is 1 to 3 weight percent; the mass percentage of the binder in the first mixed slurry is 0.5-3%.

Step S30, sintering: and carrying out dry pressing on the granulated powder to prepare a green body, and sintering the green body in a high-temperature furnace to obtain the microwave dielectric ceramic material.

Wherein, the step S30 specifically includes:

firstly, dry-pressing the granulated powder to prepare a green body;

and then, placing the green body in a high-temperature sintering furnace for glue discharging, sintering and heat preservation treatment to obtain the microwave dielectric ceramic material.

In one example, the temperature of the rubber discharge is 400-750 ℃, and the rubber discharge time is 2-4 h.

In one example, the sintering temperature is 1250-1350 ℃, and the holding time is 2-6 h.

The preparation method provided by the embodiment of the invention is based on a solid-phase sintering method, is simple, and is easy to produce and obtain the high-dielectric-constant microwave dielectric ceramic material with stable microwave performance in batch.

The above-mentioned high-permittivity microwave dielectric ceramic material and the preparation method thereof will be described with reference to specific examples, and it will be understood by those skilled in the art that the following examples are only specific examples of the above-mentioned high-permittivity microwave dielectric ceramic material and the preparation method thereof of the present invention, and are not intended to limit the entirety thereof.

Example 1: base material Ba_6-3xR_8+2xTi₁₈O₅₄Preparation of (R ═ Sm, x ═ 0.1)

Step one, taking reactant raw material BaCO of base material₃、Sm₂O₃And TiO₂The method comprises the following steps of proportioning according to a stoichiometric ratio and uniformly mixing, placing a mixture of reactant raw materials in a ball mill, adding a ball milling medium and deionized water, and carrying out wet ball milling for 10 hours to obtain a mixed slurry of the reactant raw materials of a base material, wherein the ball milling medium is prepared by mixing zirconia balls with the diameters of 3mm, 5mm and 8mm according to a mass ratio of 1: 1: 1, wherein the mass ratio of a reactant raw material mixture of the matrix material, a ball-milling medium and deionized water is 1: 3: 5;

step two, drying and sieving the mixed slurry, then placing the mixed slurry in a high-temperature box type furnace for presintering at 1100 ℃ for 3 hours to obtain mixed powder, performing wet ball milling on the mixed powder for 10 hours again, and drying and sieving the mixed powder to obtain base material powder Ba_5.7Sm_8.2Ti₁₈O₅₄。

FIG. 2 is a Ba base material of the high-k microwave dielectric ceramic material provided in example 1_5.7Sm_8.2Ti₁₈O₅₄The X-ray diffraction pattern of (A) can be understood from FIG. 2, using BaCO as a raw material₃、Sm₂O₃And TiO₂Successfully prepare Ba_5.7Sm_8.2Ti₁₈O₅₄(R is Sm and x is 0.1) phase.

Examples 2 to 9: preparation of microwave dielectric ceramic material

Examples 2 to 9 were each made of Ba as a base material_6-3xR_8+2xTi₁₈O₅₄The mass percentage of the modified additive is shown in Table 1, wherein the base material Ba of each example_6-3xR_8+2xTi₁₈O₅₄Was prepared analogously to example 1.

Table 1: base material Ba_6-3xR_8+2xTi₁₈O₅₄The mass percentage of the modified additive

Step one, according to the preset mass percentage in the table 1, the base material Ba is added_6-3xR_8+2xTi₁₈O₅₄Placing the mixture with the modified additive in a ball mill for wet ball milling for 10h to obtain mixed slurry;

step two, adding a polyvinyl alcohol aqueous solution with the concentration of 2 wt% into the mixed slurry as a binder, performing wet ball milling for 10 hours again, fully mixing the slurry, and performing spray granulation by using a spray granulation tower to obtain granulated powder; wherein the mass percentage of the polyvinyl alcohol aqueous solution in the mixed slurry is 1%;

and step three, performing dry pressing on the granulated powder under the pressure of 30MPa to form a cylindrical green body with the radius D of 15.6mm and the thickness H of 7.8mm, placing the green body in a high-temperature sintering furnace, discharging glue for 3 hours at the temperature of 600 ℃, and then preserving heat at the preset sintering temperature in the table 2 for corresponding time to obtain the high-dielectric-constant microwave dielectric ceramic material.

Electrical property tests are carried out on the obtained microwave dielectric ceramic material, fig. 3 is a scanning electron microscope image of the microwave dielectric ceramic material provided in example 5 of the present invention, and rod-shaped grains which are relatively loose and arranged in an intricate manner can be seen from fig. 3.

A square porcelain body (a square fired body) having a length L of 17mm to 17.5mm, a width W of 17mm to 17.5mm, and a height H of 3mm to 4mm was prepared according to the above method for a thermal shock test:

firstly, the temperature T of the water body of the filled water tank is measured₁Then the porcelain body is placed at a set temperature T₂After the temperature is kept for 15min in the air drying box, the porcelain body is taken out and immediately placed in a water tank, the porcelain body is taken out after 5min, the surface is wiped dry, the porcelain body is soaked for 15min by red ink, then the porcelain body is taken out, and the existence of red cracks is observed under a microscope after the porcelain body is wiped dry. If no crack exists, the set temperature T is continuously increased₂The temperature gradient is 5 ℃ until cracks appear, and the thermal shock resistance temperature is the set temperature T of the previous gradient₂Temperature T of water body₁The difference Δ T of (d).

Since the temperature gradient of each thermal shock test is 5 ℃, the temperature corresponding to the occurrence of cracks has a systematic error of-5 ℃ to 0 ℃ from the temperature at which the sample may crack (for example, if the actual thermal shock resistance temperature is 91 ℃, in the actual thermal shock test, no cracks occur when the set temperature is 90 ℃, and cracks occur when the set temperature is 95 ℃). Therefore, in order to ensure the reliability of the product, the thermal shock resistance temperature needs to be determined as the thermal shock test temperature of the previous gradient.

The electrical property test and the thermal shock resistance temperature results of the cylindrical wrought blanks and the square plate wrought blanks respectively prepared in examples 2-9 are shown in table 2:

table 2: examples 2 to 9 electric property test of cylindrical green compact and thermal shock resistance temperature of square plate green compact

As shown in Table 2, the microwave dielectric ceramic materials of examples 2 to 9 had dielectric constants ε r of 62.4 to 97.8 and quality factors Q_fNot less than 5729GHz and at most 16392GHz, and temperature coefficient of resonance frequency tau_fIs-7.6 ppm/DEG C to +6.2 ppm/DEG C, has the maximum value delta T of thermal shock resistance temperature to 210 ℃, is close to a continuous adjustable series ceramic material, and can meet the requirement of microwave dielectricThe application requirements of the device.

The high-dielectric-constant microwave dielectric ceramic material provided by the embodiment of the invention comprises 91-97 mass percent of Ba_6-3xR_8+2xTi₁₈O₅₄A base material and a modified additive with the mass percentage of 3-9 percent. By regulating and controlling the base material Ba_6-3xR_8+2xTi₁₈O₅₄The value of x, the element represented by R and the content of the element can be expanded to Ba_6-3xR_8+2xTi₁₈O₅₄The dielectric constant of the ceramic material can be adjusted, the resonant frequency temperature coefficient of the ceramic material can be adjusted to be close to zero by introducing the modified additive, the problem of 'black heart' of the ceramic material in the sintering process due to the fact that Ti is easy to reduce in the high-temperature sintering process is solved, and the electrical property of the ceramic material is stabilized. Thus, Ba obtained by the preparation_6-3xR_{8+ 2x}Ti₁₈O₅₄The microwave dielectric ceramic material has the excellent performances of adjustable dielectric constant, high quality factor, adjustable resonant frequency temperature coefficient in a near-zero range and high thermal shock resistance. The method solves the problems that the high-dielectric-constant microwave dielectric ceramic material prepared by the prior art has over-negative temperature coefficient of resonant frequency, poor thermal stability and low electrical performance caused by easy Ti reduction, can adapt to the application of various devices and the use requirements of trans-regional climatic environments of the devices, and can be used for preparing microwave devices such as 5G filters, military radars, indoor antennas and the like.

In addition, the preparation method of the microwave dielectric ceramic material provided by the embodiment of the invention is based on a solid-phase sintering method, is simple, and is easy to produce in batch to obtain the high-dielectric-constant microwave dielectric ceramic material with stable microwave performance.

The foregoing description has described certain embodiments of this invention. Other embodiments are within the scope of the following claims.

The terms "exemplary," "example," and the like, as used throughout this specification, mean "serving as an example, instance, or illustration," and do not mean "preferred" or "advantageous" over other embodiments. The detailed description includes specific details for the purpose of providing an understanding of the described technology. However, the techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described embodiments.

Alternative embodiments of the present invention are described in detail with reference to the drawings, however, the embodiments of the present invention are not limited to the specific details in the above embodiments, and within the technical idea of the embodiments of the present invention, many simple modifications may be made to the technical solution of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the description is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.