CN101955356A - Tunable dielectric barium strontium titanate based composite silicate microwave dielectric material and preparation thereof - Google Patents

Abstract

The invention belongs to the technical field of electronic materials and devices, and discloses a strontium barium titanate-based composite silicate ceramic dielectric material with adjustable dielectric and its preparation. The compositional formula of the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material of the present invention is: (1-m%)Ba _1-z Sr _z TiO ₃ +m%(Sr _1-x A _x ) ₂ (Zn _1-y By _y )Si ₂ O ₇ ; wherein, A is selected from Ba or Ca, B is selected from Co, Mg, Mn or Ni; the range of x is 0≤x≤1; y The value range is 0≤y≤1; the value range of z is 0.4≤z≤0.6; the value range of m is 0wt%<m%<100wt%. The dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material of the present invention has a high Q value, a low dielectric constant, and a high dielectric adjustable rate, and can be widely used in the preparation of electrical tuning Tunable microwave components such as microwave resonators, filters, and microwave dielectric antennas.

Description

Strontium Barium Titanate Based Composite Silicate Microwave Dielectric Material with Adjustable Dielectric and Its Preparation

technical field

The invention belongs to the technical field of electronic materials and devices, and in particular relates to a dielectrically adjustable strontium barium titanate-based composite silicate microwave dielectric material and its preparation.

Background technique

The ferroelectric material with perovskite structure strontium barium titanate with high dielectric constant, low dielectric loss, non-linear tunable dielectric constant and tunable Curie temperature is used as a microwave tunable device (such as phase shifter, filter devices, variable capacitors and delay lines, etc.) have received increasing attention, especially as a microwave phase shifter is a current research hotspot. However, the BST ceramic material with high dielectric constant is difficult to meet the requirements of internal impedance matching and high power of the excitation source, which greatly limits its application in the field of microwave tunable devices. The Q value is the main parameter to measure the inductance device. The Q value refers to the ratio of the inductive reactance presented by the inductor to its equivalent loss resistance when the inductor operates under an AC voltage of a certain frequency. The higher the Q value of an inductor, the smaller its losses and the higher its efficiency. The dielectric constant of barium strontium titanate BST material changes with the change of the external DC electric field. When the voltage changes from V(0) to V(app), the dielectric constant will produce an increment Δεr=[ _εr(0) -ε _r(app) ], the percentage of the ratio of this increment to ε _r(0) becomes adjustable, that is, Tunability (abbreviated as T)=[ε _r(0) -ε _r(app) ]/ε _r(0) × 100% to represent. At the same time, when light (microwave) of a special frequency is applied, a corresponding difference phase shift will be generated to achieve the purpose of changing the phase. Materials with this property are called electro-optic materials. The ability of the phase shifter to change the phase angle is mainly determined by the tunability, so high tunability is very necessary for the phase shifter material.

Therefore, how to prepare a material system with low dielectric constant, high Q value, and high dielectric tunable characteristics is a technical difficulty.

Ceramic compounding has always been one of the most commonly used and most effective means of modifying electronic ceramic materials. Through the compounding of materials with different mass ratios, they enter the lattice structure of crystal materials in different degrees and in different ways, causing the microstructure of materials to change. In order to effectively adjust and improve the relevant properties of materials. In the prior art, some researchers used MgO, MgAl ₂ O ₆ , etc. to compound strontium barium titanate with different mass ratios, and developed a ceramic dielectric material system with low dielectric constant, high Q value and certain dielectric tunable characteristics. Xiujian Chou et al. from Tongji University conducted systematic research on magnesium titanate composited with strontium barium titanate at different molar ratios, and obtained microwave ceramic dielectric materials ( _εr = 190, Q = 189, T = 18.1). However, the overall performance of the system needs to be further improved. There are no related reports on the microwave dielectric tunable properties of barium strontium titanate composite silicate materials.

Contents of the invention

The object of the present invention is to provide a kind of strontium barium titanate-based composite silicate ceramic dielectric material with adjustable dielectric and its preparation. The dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material has high Q value and dielectric tunable characteristics.

The dielectrically adjustable barium strontium titanate-based composite silicate ceramic dielectric material of the present invention has a general chemical formula of its components: (1-m%)Ba _1-z Sr _z TiO ₃ +m%(Sr _{1 -x} A _x ) ₂ (Zn _{1-y By} )Si ₂ O ₇ ; wherein, A is selected from Ba or Ca, B is selected from Co, Mg, Mn or Ni; the value range of x is 0≤x≤1 The value range of y is 0≤y≤1; the value range of z is 0.4≤z≤0.6; the value range of m is 0wt%<m%<100wt%.

Preferably, the value range of x is 0.1≤x≤0.6; 0≤y≤0.5; 0.4≤z≤0.6; 40wt%≤m%≤60wt%.

More preferably, the 0.1≤x≤0.6, y=0, z=0.5, m%=60wt%; that is, the composition of the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material is generally The formula is: 40% Ba _0.5 Sr _0.5 TiO ₃ +60% (Sr _1-x Ba _x ) ₂ ZnSi ₂ O ₇ .

In the general composition formula of the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material, the number in the lower right corner of the element represents the mole number of each corresponding element; Based on the total mass of the composite silicate ceramic dielectric material, the mass percent of (Sr _1-x A _x ) ₂ (Zn _1-y By ₎ Si ₂ O ₇ ; (1-m)% represents the titanium The mass percent of Ba _1-z Sr _z TiO ₃ is based on the total mass of strontium barium acid-based composite silicate ceramic dielectric material.

The preparation method of the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material specifically comprises the following steps:

1) The mixed powder is prepared by solid-phase synthesis method, and the specific steps are:

Choose _BaCO3 powder, SrCO3 powder, TiO2 powder, _SiO2 powder, ZnO powder, _ACO3 powder and B oxide or carbonate powder as the main raw materials, according to (1-m%) Ba The stoichiometric ratio of Ba, Sr, Ti, Si, Zn, A and B in _1-z Sr _z TiO ₃ +m%(Sr _1-x A _x ) ₂ (Zn _{1-y By} y )Si ₂ O ₇ , put the prepared raw materials in a nylon ball mill tank, add zirconia balls and ball milling media, and then carry out ball milling, and then pre-calcine and grind the mixed powder to obtain the mixed powder after drying;

Preferably, the pre-burning temperature is 1000°C-1300°C, and the pre-burning time is 2-4 hours; further, the pre-burning temperature is 1000-1200°C.

2) Add zirconia balls and ball milling media to the mixed powder prepared in step 1), and sieve the discharged material after drying;

Preferably, the mesh of the sieve is 100-300 mesh, further, the mesh of the sieve is 200 mesh.

3) Using a binder to granulate the powder sieved in step 2), and press it under a pressure of 10MPa to 100MPa to form a ceramic green sheet;

Preferably, the binder is an aqueous solution of polyvinyl alcohol (PVA) with a mass percentage of 8% to 10%.

4) Sintering the ceramic green sheet obtained in step 3) after debonding treatment to obtain the strontium barium titanate-based composite silicate ceramic dielectric material.

Preferably, the debonding treatment temperature in step 4) is 550°C-600°C, and the holding time is 4-10 hours; the sintering temperature is 1200°C-1500°C, and the sintering time is 4-10 hours. Further, the temperature of the debonding treatment is 550°C; the sintering temperature is 1230°C-1380°C.

Preferably, the time of ball milling in step 1) and step 2) is 20-24 hours, and the ball milling media are all selected from absolute ethanol or deionized water.

Preferably, during the ball milling process in step 1) and step 2), the mass ratio of zirconia balls to ball milling material is 1.2-1.5:1; the mass ratio of ball milling media to ball milling material is 1.5-3.0:1.

The ball milling material refers to the raw material for ball milling, and the raw material for ball milling in step 1) is CaCO ₃ powder, Co ₂ O ₃ powder, MgO powder, MnCO ₃ powder, NiO powder, BaCO ₃ , SrCO ₃ and _TiO The mixed raw material of powder composition, the raw material of ball milling in step 2) is the mixed powder of pre-burning.

The present invention adopts the traditional preparation technology of electronic ceramics, according to the mass ratio of Ba _1-z Sr _z TiO ₃ and (Sr _1-x A _x ) ₂ (Zn _1-y By ₎ Si ₂ O ₇ to compound, develop and obtain usable The high-Q, high-dielectric adjustable strontium barium titanate-based composite silicate ceramic dielectric material for adjustable microwave devices, and the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material of the present invention Has the following main features:

(1) The Curie temperature of the ceramic material system can vary with Ba/Sr, Ca/Sr and (1-m%) Ba _1-z Sr _z TiO ₃ +m% (Sr _1-x A _x ) ₂ (Zn _{1 -yB y} ) Si ₂ O ₇ (A=Ba or Ca; B=Co, Mg, Mn or Ni; x=0~1; y=0~1; z=0.4~0.6; 0wt%<m%< 100wt%) mass ratio is continuously adjustable in a wide range, and the structure and performance of the material system can be adjusted according to the working temperature requirements of the designed adjustable microwave device;

(2) Through Ba/Sr, Ca/Sr and (1-m%) Ba _1-z Sr _z TiO ₃ +m% (Sr _1-x A _x ) ₂ (Zn _{1-y By} ) Si ₂ O ₇ (A=Ba or Ca; B=Co, Mg, Mn or Ni; x=0～1; y=0～1; z=0.4～0.6; m%=5wt%～80wt%) the change of component ratio, The dielectric constant of the ceramic dielectric material can be continuously adjusted, and a material system with a serialized dielectric constant can be obtained, which broadens the application range of the material;

(3) It has high Q value (low dielectric loss) (Q value can reach 417), low dielectric constant (152), high adjustable rate (adjustable rate can reach 16%), and the dielectric constant Serialization (that is, the dielectric constant can be controlled by changing the value of m to adjust the mass percentage of the component and adjusting the ratio of Ca, Sr and Ba, Sr with the change of x and z values to achieve the controllability of the dielectric constant).

(4) Its composition coexists with Ba _1-z Sr _z TiO ₃ phase and (Sr _1-x A _x ) ₂ (Zn _1-y By _y ) Si ₂ O ₇ phase, and has excellent microwave dielectric properties;

(5) The traditional electronic ceramic preparation technology is adopted, the process is simple, the cost is low, the material system is environmentally friendly, non-toxic and side effects, and the performance is excellent. It is suitable for materials for adjustable microwave components such as electrically tuned microwave resonators, filters, and microwave dielectric antennas.

Description of drawings

Fig. 1 is an X-ray diffraction analysis pattern of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ tunable microwave ceramic dielectric material.

Fig. 2 is the relationship curve of dielectric constant and loss with temperature of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ tunable microwave ceramic dielectric material.

Fig. 3 is the relationship curve between the dielectric constant and the electric field intensity of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ tunable microwave ceramic dielectric material.

Fig. 4 is an X-ray diffraction analysis spectrum of 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ tunable microwave ceramic dielectric material.

Fig. 5 is the relationship curve of dielectric constant and loss with temperature of 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ tunable microwave ceramic dielectric material.

Fig. 6 is a graph showing the relationship between the dielectric constant and the electric field intensity of 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ tunable microwave ceramic dielectric material.

Detailed ways

The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the protection scope of the present invention.

Example 1 Preparation of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% (Sr _0.5 Ba _0.5 ) ₂ ZnSi ₂ O ₇ ceramic dielectric material with high Q value and adjustable dielectric

The raw materials of BaCO ₃ , SrCO ₃ , TiO _{2 ,} ZnO and SiO ₂ were weighed according to the molar ratio of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ (as shown in Table 1).

Raw material sources: BaCO ₃ (99.8%, Alfa Aesar China LTD.), SrCO ₃ (99.0%, Alfa Aesar China LTD.), TiO ₂ (99.9%, Foshan Gaoxin Inorganic Materials Co., Ltd.) and ZnO (99.99%, Sinopharm Chemical Reagent Co., Ltd.), SiO ₂ (99.9%, Sinopharm Chemical Reagent Co., Ltd.).

Table 1. Raw material ratio of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ ceramic dielectric material

formula BaCO ₃ SrCO ₃ TiO ₂ ZnO SiO ₂ Mass/g 13.459 10.148 4.605 3.196 4.722

生坯片和10mm×5mm、12mm×6mm、15mm×7mm、18mm×8mm的圆柱体，经过550℃排粘处理10小时后，样品在空气气氛下，烧结温度为1230℃，保温4小时后，得到40％Ba_0.5Sr_0.5TiO₃+60％BaSrZnSi₂O₇陶瓷样品。将制得的陶瓷样品先进行物相和微结构分析，然后对其两面抛光、被银，烧银后进行介电性能测试，其相关介电性能见表2。Mix the above powders according to Ba _0.5 Sr _0.5 TiO ₃ and BaSrZnSi ₂ O ₇ respectively and place them in a nylon ball mill jar, add zirconia balls and absolute ethanol or deionized water, and ball mill for 24 hours. Pre-fired at 1200°C and 1000°C for 4 hours, the ground powder was placed in a nylon ball mill jar, and zirconia balls were added (the mass ratio of zirconia balls to ball grinding material was 1.2:1) and deionized water (deionized The mass ratio of ionized water to ball abrasive is 3.0:1), ball milled for 24 hours, and the powder passed through a 200-mesh sieve after discharging and drying; according to the traditional electronic ceramic preparation process, 8% polyvinyl alcohol (PVA) was used as the bonding agent. The agent is granulated, and under the pressure of 10MPa, it is dry pressed into a diameter

Green sheets and cylinders of 10mm×5mm, 12mm×6mm, 15mm×7mm, and 18mm×8mm were subjected to debonding treatment at 550°C for 10 hours, and the samples were sintered in an air atmosphere at a temperature of 1230°C for 4 hours. A 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ ceramic sample was obtained. The phase and microstructure of the prepared ceramic samples were first analyzed, and then the dielectric properties were tested on both sides of the ceramic samples after being polished, silvered, and silver fired. The relevant dielectric properties are shown in Table 2.

Table 2. Relative dielectric properties of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ dielectrically tunable microwave ceramic dielectric materials

In this embodiment, the X-ray diffraction analysis pattern of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ dielectrically tunable microwave ceramic dielectric material is shown in FIG. 1 . The results in Figure 1 show that its composition coexists in Ba _0.5 Sr _0.5 TiO ₃ phase and BaSrZnSi ₂ O ₇ phase structure.

In this embodiment, the relationship curves of dielectric constant, loss and temperature of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ dielectrically adjustable microwave ceramic dielectric materials are shown in Figure 2, and the results in Figure 2 It shows that the Curie peak of the stoichiometric composite BaSrZnSi ₂ O ₇ does not continue to move to the low temperature direction with the increase of the composite amount. Losses remain very small over a long temperature range.

In this embodiment, the relationship curve between the dielectric constant and the electric field intensity of 40% Ba _0.5 Sr _0.5 TiO ₃ +60% BaSrZnSi ₂ O ₇ dielectrically adjustable microwave ceramic dielectric material is shown in Figure 3, and the test results in Figure 3 It shows that there is a higher dielectric tunability with the recombination of BaSrZnSi ₂ O ₇ . After compounding, very ideal comprehensive microwave dielectric properties are obtained.

Example 2 Preparation of 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ Ceramic Dielectric Material with High Q Value and Adjustable Dielectric

According to the molar ratio of 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ , weigh BaCO ₃ , SrCO ₃ , TiO ₂ and ZnO, Co ₂ O ₃ and SiO ₂ raw materials (the specific quality is shown in Table 3).

Raw material sources: BaCO ₃ (99.8%, Alfa Aesar China LTD.), SrCO ₃ (99.0%, Alfa Aesar China LTD.), TiO ₂ (99.9%, Foshan Gaoxin Inorganic Materials Co., Ltd.) and ZnO (99.9%, Sinopharm Group Chemical Reagent Co., Ltd.), Co ₂ O ₃ (99.9%, Sinopharm Chemical Reagent Co., Ltd.), SiO ₂ (99.9%, Sinopharm Chemical Reagent Co., Ltd.).

Table 3. Raw material ratio of 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ ceramic dielectric material

formula BaCO ₃ SrCO ₃ TiO ₂ ZnO Co ₂ O ₃ SiO ₂ Mass/g 13.083 10.977 7.076 1.984 0.213 3.083

生坯片和10mm×5mm、12mm×6mm、15mm×7mm、18mm×8mm的圆柱体，经过550℃排粘处理10小时后，样品在空气气氛下，烧结温度为1350℃，保温6小时后，得到60％Ba_0.4Sr_0.6TiO₃+40％(Sr_0.4Ba_0.6)₂(Zn_0.95Co_0.05)Si₂O₇陶瓷样品。将制得的陶瓷样品先进行物相和微结构分析，然后对其两面抛光、被银，烧银后进行介电性能测试，其相关介电性能见表4。Mix the above powders according to Ba _0.4 Sr _0.6 TiO ₃ and (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ respectively and place them in a nylon ball mill jar, add zirconia balls and absolute ethanol or deionized water, ball milled for 24 hours, and after the discharge was dried, it was pre-fired at 1100°C and 1000°C for 4 hours respectively. The ground powder was placed in a nylon ball mill jar, and zirconia balls (the mixture of zirconia balls and ball mill materials) were added. The mass ratio is 1.5:1) and absolute ethanol or deionized water (the mass ratio of water ethanol or deionized water to the ball mill is 1.5:1), ball milled for 24 hours, and the powder is passed through a 200-mesh sieve after discharging and drying; According to the traditional electronic ceramic preparation process, 10% polyvinyl alcohol (PVA) is used as a binder for granulation, and under a pressure of 100MPa, it is dry-pressed into a diameter

Green sheets and cylinders of 10mm×5mm, 12mm×6mm, 15mm×7mm, and 18mm×8mm were subjected to debonding treatment at 550°C for 10 hours, and the samples were sintered in an air atmosphere at a temperature of 1350°C for 6 hours. A 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ ceramic sample was obtained. The phase and microstructure of the prepared ceramic samples were firstly analyzed, and then the dielectric properties were tested on both sides after polishing, silvering, and silver burning. The relevant dielectric properties are shown in Table 4.

Table 4. Relative dielectric properties of 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ dielectrically tunable microwave ceramic dielectric materials

In this example, the X-ray diffraction analysis pattern of 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ dielectrically tunable microwave ceramic dielectric material is shown in Figure 4 shown. The results in Fig. 4 show that its composition coexists in Ba _0.4 Sr _0.6 TiO ₃ phase and (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ phase structure.

In this example, 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ dielectric constant and loss versus temperature The relationship curve is shown in Figure 5, and the results in Figure 5 show that the Curie peak in the stoichiometric composite system does not continue to move to the low temperature direction with the increase of the composite amount. Losses remain very small over a long temperature range.

In this embodiment, the relationship between the dielectric constant and electric field intensity of 60% Ba _0.4 Sr _0.6 TiO ₃ +40% (Sr _0.4 Ba _0.6 ) ₂ (Zn _0.95 Co _0.05 ) Si ₂ O ₇ dielectrically adjustable microwave ceramic dielectric material The curve is shown in Figure 6, and the test results in Figure 6 show that the composite system maintains high dielectric tunability. After compounding, very ideal comprehensive microwave dielectric properties are obtained.

Example 3 A high-Q electrically tunable 50% Ba _0.5 Sr _0.5 TiO ₃ +50% (Sr _0.9 Ca _0.1 ) ₂ (Zn _0.5 Mg _0.5 ) Si ₂ O ₇ ceramic dielectric material was prepared.

_{Weigh BaCO 3 , SrCO 3 ,} TiO _{2 and ZnO , MgO ,} SiO ₂ raw materials (as shown in Table 5).

Raw material sources: BaCO ₃ (99.8%, Alfa Aesar China LTD.), SrCO ₃ (99.0%, Alfa Aesar China LTD.), TiO ₂ (99.9%, Foshan Gaoxin Inorganic Materials Co., Ltd.) and ZnO (99.99%, Sinopharm Chemical Reagent Co., Ltd.), MgO (99.9%, Sinopharm Chemical Reagent Co., Ltd.), SiO ₂ (99.9%, Sinopharm Chemical Reagent Co., Ltd.).

Table 5. Raw material ratio of 50% Ba _0.5 Sr _0.5 TiO ₃ +50% (Sr _0.9 Ca _0.1 ) ₂ (Zn _0.5 Mg _0.5 ) Si ₂ O ₇ ceramic dielectric material

formula BaCO ₃ SrCO ₃ TiO ₂ ZnO MgO SiO ₂ Mass/g 7.118 15.998 5.756 1.612 0.799 4.764

Mix the above powders according to Ba _0.5 Sr _0.5 TiO ₃ and (Sr _0.9 Ca _0.1 ) ₂ (Zn _0.5 Mg _0.5 ) respectively and place them in a nylon ball mill jar, add zirconia balls and absolute ethanol or deionized water, and ball mill for 24 Hours, after discharging and drying, pre-fired at a temperature of 1200°C and 1000°C for 2 hours, the ground powder was placed in a nylon ball mill jar, and zirconia balls were added (the mass of zirconia balls and ball mills Ratio is 1.2) and deionized water (the mass ratio of deionized water and ball mill is 3.0), ball milled for 24 hours, and the powder body passed through a 200 mesh sieve after discharging and drying; according to the traditional electronic ceramic preparation process, 8% poly Vinyl alcohol (PVA) is used as a binder for granulation, and under a pressure of 10MPa, it is dry-pressed into a diameter Green sheets and cylinders of 10mm×5mm, 12mm×6mm, 15mm×7mm, and 18mm×8mm were subjected to debonding treatment at 550°C for 10 hours, and the samples were sintered in an air atmosphere at a temperature of 1380°C for 10 hours. A 50% Ba _0.5 Sr _0.5 TiO ₃ +50% (Sr _0.9 Ca _0.1 ) ₂ (Zn _0.5 Mg _0.5 ) Si ₂ O ₇ ceramic sample was obtained. The phase and microstructure of the prepared ceramic samples were firstly analyzed, and then the dielectric properties were tested on both sides after polishing, silvering, and silver firing. The relevant dielectric properties are shown in Table 6.

Table 6.50% Ba _0.5 Sr _0.5 TiO ₃ +50% (Sr _0.9 Ca _0.1 ) ₂ (Zn _0.5 Mg _0.5 ) Si ₂ O ₇ Correlated dielectric properties of dielectrically tunable microwave ceramic dielectric materials

In this example, 50% Ba _0.5 Sr _0.5 TiO ₃ +50% (Sr _0.9 Ca _0.1 ) ₂ (Zn _0.5 Mg _0.5 ) Si ₂ O ₇ dielectrically adjustable microwave ceramic dielectric material is composed of Ba _0.5 Sr _0.5 TiO ₃ phase and (Sr _0.9 Ca _0.1 ) ₂ (Zn _0.5 Mg _0.5 ) Si ₂ O ₇ phase structure coexist.

In this example, the Curie peak in the composite system of 50% Ba _0.5 Sr _0.5 TiO ₃ +50% (Sr _0.9 Ca _0.1 ) ₂ (Zn _0.5 Mg _0.5 ) Si ₂ O ₇ does not continue to move to the low temperature direction with the increase of the composite amount. Losses remain very small over a long temperature range.

In this embodiment, the 50% Ba _0.5 Sr _0.5 TiO ₃ +50% (Sr _0.9 Ca _0.1 ) ₂ (Zn _0.5 Mg _0.5 ) Si ₂ O ₇ composite system maintains high dielectric tunability. After compounding, very ideal comprehensive microwave dielectric properties are obtained.

Example 4 Preparation of 45% Ba _0.6 Sr _0.4 TiO ₃ +55% (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn _0.1 ) Si ₂ O ₇ Ceramic Dielectric Material with High Q Value and Adjustable Dielectric

According to the molar ratio of 45% Ba _0.6 Sr _0.4 TiO ₃ +55% (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn _0.1 ) Si ₂ O ₇ , weigh BaCO ₃ , SrCO ₃ , TiO ₂ and ZnO, MnCO ₃ , SiO ₂ raw material (concrete quality is as shown in table 7).

Raw material sources: BaCO ₃ (99.8%, Alfa Aesar China LTD.), SrCO ₃ (99.0%, Alfa Aesar China LTD.), TiO ₂ (99.9%, Foshan Gaoxin Inorganic Materials Co., Ltd.) and ZnO (99.9%, Sinopharm Group Chemical Reagent Co., Ltd.), MnCO ₃ (99.9%, Sinopharm Chemical Reagent Co., Ltd.), SiO ₂ (99.9%, Sinopharm Chemical Reagent Co., Ltd.).

Table 7. Raw material ratio of 45% Ba _0.6 Sr _0.4 TiO ₃ +55% (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn _0.1 ) Si ₂ O ₇ ceramic dielectric material

formula BaCO ₃ SrCO ₃ TiO ₂ ZnO MnCO ₃ SiO ₂ Mass/g 14.640 9.153 5.060 2.645 0.343 4.339

生坯片和10mm×5mm、12mm×6mm、15mm×7mm、18mm×8mm的圆柱体，经过550℃排粘处理10小时后，样品在空气气氛下，烧结温度为1350℃，保温6小时后，得到45％Ba_0.6Sr_0.4TiO₃+55％(Sr_0.5Ba_0.5)₂(Zn_0.9Mn_0.1)Si₂O₇陶瓷样品。将制得的陶瓷样品先进行物相和微结构分析，然后对其两面抛光、被银，烧银后进行介电性能测试，其相关介电性能见表4。The above powders were mixed according to 45% Ba _0.6 Sr _0.4 TiO ₃ + 55% (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn _0.1 ) Si ₂ O ₇ respectively, and then placed in a nylon ball mill jar, adding zirconia balls and anhydrous Ethanol or deionized water, ball milled for 24 hours, pre-fired at 1200°C and 1000°C for 4 hours after the discharge was dried, and the ground powder was placed in a nylon ball mill jar, and zirconia balls (zirconia balls The mass ratio to the ball mill is 1.5: 1) and absolute ethanol or deionized water (the mass ratio of water ethanol or deionized water to the ball mill is 1.5: 1), ball milled for 24 hours, and the powder is dried after discharging 200 mesh sieve; according to the traditional electronic ceramic preparation process, use 10% polyvinyl alcohol (PVA) as a binder for granulation, and dry press it into diameter under 100MPa pressure

Green sheets and cylinders of 10mm×5mm, 12mm×6mm, 15mm×7mm, and 18mm×8mm were subjected to debonding treatment at 550°C for 10 hours, and the samples were sintered in an air atmosphere at a temperature of 1350°C for 6 hours. A 45% Ba _0.6 Sr _0.4 TiO ₃ +55% (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn _0.1 ) Si ₂ O ₇ ceramic sample was obtained. The phase and microstructure of the prepared ceramic samples were firstly analyzed, and then the dielectric properties were tested on both sides after polishing, silvering, and silver burning. The relevant dielectric properties are shown in Table 4.

Table 8.45% Ba _0.6 Sr _0.4 TiO ₃ +55% (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn _0.1 ) Si ₂ O ₇ Correlated dielectric properties of dielectric tunable microwave ceramic dielectric materials

In this example, the X-ray diffraction analysis pattern of 45% Ba _0.6 Sr _0.4 TiO ₃ +55% (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn0.1) Si ₂ O ₇ dielectrically adjustable microwave ceramic dielectric material is shown in the figure 4. The results in Fig. 4 show that its composition coexists in Ba _0.4 Sr _0.6 TiO ₃ phase and (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn _0.1 ) Si ₂ O ₇ phase structure.

In this embodiment, 45% Ba _0.6 Sr _0.4 TiO ₃ +55% (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn _0.1 ) Si ₂ O ₇ dielectric constant and loss versus temperature of dielectrically adjustable microwave ceramic dielectric material The relationship curve is shown in Figure 5, and the results in Figure 5 show that the Curie peak in the stoichiometric composite system does not continue to move to the low temperature direction with the increase of the composite amount. Losses remain very small over a long temperature range.

In this example, the composite system of 45% Ba _0.6 Sr _0.4 TiO ₃ +55% (Sr _0.5 Ba _0.5 ) ₂ (Zn _0.9 Mn _0.1 ) Si ₂ O ₇ maintains high dielectric tunability. After compounding, very ideal comprehensive microwave dielectric properties are obtained.

Claims (9)

1. A strontium barium titanate-based composite silicate ceramic dielectric material with adjustable dielectric, the general formula of its components is: the general chemical formula of its components is: (1-m%) Ba _1-z Sr _z TiO ₃ +m%(Sr _1-x A _x ) ₂ (Zn _1-y By _y )Si ₂ O ₇ ; wherein, A is selected from Ba or Ca, B is selected from Co, Mg, Mn or Ni; The value range of 0≤x≤1; the value range of y is 0≤y≤1; the value range of z is 0.4≤z≤0.6; the value range of m is 0wt%<m%<100wt%. 2. The dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material according to claim 1, wherein the value range of x is 0.1≤x≤0.6; the value range of y is 0≤ y≤0.5; the value range of z is 0.4≤z≤0.6; the value range of m is 40wt%≤m%≤60wt%. 3. The preparation method of the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material as claimed in claim 1 or 2, comprising the steps of: 1), select BaCO ₃ powder, SrCO 3 powder, TiO 2 powder, SiO ₂ powder, ZnO powder, ACO ₃ powder and oxide or carbonate powder of B as the main raw material, according to (1-m %)Ba _1-z Sr _z TiO ₃ +m%(Sr _1-x A _x ) ₂ (Zn _1-y B _y )Si ₂ O ₇ Chemistry of Ba, Sr, Ti, Si, Zn, A and B Measuring and proportioning, put the prepared raw materials in a nylon ball mill tank, add zirconia balls and ball milling media, and then perform ball milling, and then pre-calcine and grind the mixed powder to obtain the mixed powder; 2), the mixed powder obtained in step 1), adding zirconia balls and ball milling medium ball milling, sieving after discharging; 3), using a binder to granulate the powder sieved in step 2), and press it under a pressure of 10MPa to 100MPa to form a ceramic green sheet; 4) Sintering the ceramic green sheet prepared in step 3) after debonding treatment to obtain the strontium barium titanate-based composite silicate ceramic dielectric material. 4. The preparation method of the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material as claimed in claim 3, characterized in that, in step 1), the pre-firing temperature is 1000°C to 1300°C , The pre-burning time is 2 to 4 hours. 5. as claimed in claim 3, the preparation method of the adjustable strontium titanate-based composite silicate ceramic dielectric material is characterized in that, the ball milling time in the step 1) and step 2) is 20 ~24 hours, the ball milling media are all selected from absolute ethanol or deionized water. 6. as claimed in claim 3, the preparation method of the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material is characterized in that, in the step 3), the binder is 8% to 8% by mass. 10% polyvinyl alcohol in water. 7. The preparation method of the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material as claimed in claim 3, characterized in that, the temperature of the debonding treatment in the step 4) is 550° C. to 600°C, the holding time is 4 to 10 hours. 8. The method for preparing the dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material as claimed in claim 3, wherein the sintering temperature in step 4) is 1200°C to 1500°C, The sintering time is 4 to 10 hours. 9. The dielectrically adjustable strontium barium titanate-based composite silicate ceramic dielectric material according to claim 1 or 2 is used for preparing adjustable microwave components.

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