High-entropy perovskite microwave dielectric ceramic with medium-high dielectric constant as well as preparation method and application of high-entropy perovskite microwave dielectric ceramic

Abstract

The invention discloses a high-entropy perovskite microwave dielectric ceramic with medium and high dielectric constants and a preparation method and application thereof, the stoichiometric formula of the high-entropy perovskite microwave dielectric ceramic is (Ca < 0.2 > Li < 0.2 > Sm < 0.2 > Mg < 0.2 > Me < 0.2 >) TiO3, Me is Zn, Ba or Sr; the microwave dielectric constant of the microwave dielectric ceramic is 50-115, the quality factor is 2000-11000 GHz, and the temperature coefficient of resonance frequency is 40-140 ppm / DEG C. The high-entropy perovskite microwave dielectric ceramic with excellent microwave dielectric properties is prepared through a simple, green and environment-friendly process, and the sintering temperature is effectively reduced under the condition that a sintering aid is not added; the method has important significance in promoting the application of the perovskite structure microwave dielectric ceramic in microwave antennas and 6G base stations in the field of mobile communication.

Description

Technical Field

[0001] This invention belongs to the field of electronic ceramics technology, specifically a high-entropy perovskite microwave dielectric ceramic with medium to high dielectric constant, its preparation method, and its application. Background Technology

[0002] With the popularization and development of mobile communication technology, the demand for high-performance microwave dielectric ceramic materials is becoming increasingly urgent. In particular, key microwave dielectric materials with medium to high dielectric constant, quality factor and near-zero resonant frequency temperature coefficient are needed in core devices such as base station filters, resonators and antennas to achieve miniaturized integration, high frequency selectivity and excellent temperature stability of devices.

[0003] Although traditional perovskite microwave dielectric ceramics possess a good foundation in dielectric properties, pursuing higher performance often presents challenges. On the one hand, the sintering temperature of materials with medium to high dielectric constants is relatively high, increasing energy consumption costs and hindering pollution prevention and emission reduction. On the other hand, adding sintering aids to lower the sintering temperature may introduce impurity phases, thereby deteriorating microwave dielectric properties and affecting the long-term reliability of devices. Furthermore, traditional doping modification strategies often suffer from the limitation of "one gain at the expense of another" in performance regulation, making it difficult to maintain a high quality factor and a low temperature coefficient of resonant frequency while increasing the dielectric constant, severely restricting breakthroughs in material performance.

[0004] In recent years, high-entropy ceramics have achieved remarkable results in the field of functional dielectric ceramics due to their unique "cocktail effect". However, their application research in microwave dielectric ceramics is still in its infancy. In particular, research on the preparation of medium-high dielectric perovskite-based microwave dielectric ceramic materials with single-phase or controllable multiphase structures using high-entropy strategies combined with directional element selection is still blank.

[0005] Therefore, developing a novel high-entropy perovskite-based material that is simple to process, environmentally friendly, can effectively reduce sintering temperature, and has medium-to-high microwave dielectric properties is of great scientific significance and application value in order to meet the urgent needs of next-generation mobile communication systems for high-performance, miniaturized, and highly reliable microwave devices. Summary of the Invention

[0006] The purpose of this invention is to provide a high-entropy perovskite microwave dielectric ceramic with medium to high dielectric constant, its preparation method and application. A high-entropy perovskite microwave dielectric ceramic with excellent microwave dielectric properties is prepared by a simple, green and environmentally friendly process, and the sintering temperature is effectively reduced without adding sintering aids.

[0007] This invention is achieved through the following technical solution:

[0008] A high-entropy perovskite microwave dielectric ceramic with medium to high dielectric constant, stoichiometric formula: (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Me 0.2 TiO3, wherein Me is Zn, Ba or Sr; microwave dielectric constant is 50 to 115, quality factor is 2000 to 11000 GHz, and resonant frequency temperature coefficient is 40 to 140 ppm / ℃.

[0009] Furthermore, the chemical formula is (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 has a microwave dielectric constant of 50, a quality factor of 11000 GHz, and a resonant frequency temperature coefficient of 40 ppm / ℃.

[0010] A method for preparing a high-entropy perovskite microwave dielectric ceramic with medium to high dielectric constant includes the following steps:

[0011] Step 1, Preparation of (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Me 0.2 The specific process for calcining TiO3 powder is as follows:

[0012] When Me is Zn, according to the stoichiometric formula (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 was prepared by weighing out CaCO3, Li2CO3, Sm2O3, MgO, and ZnO, mixing them, and then sequentially subjecting them to wet ball milling and drying. Finally, the mixture was calcined at 800–1000℃ for 2–4 hours to obtain (CaCO3)2O3. 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 Calcinated TiO3 powder;

[0013] When Me is Ba, according to the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 was prepared by weighing out CaCO3, Li2CO3, Sm2O3, MgO, and BaCO3, mixing them, and then sequentially subjecting them to wet ball milling and drying. Finally, the mixture was calcined at 850–1050 °C for 2–4 hours to obtain (CaCO3)2O3.0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 Calcinated TiO3 powder;

[0014] When Me is Sr, according to the stoichiometric formula (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 was prepared by weighing out CaCO3, Li2CO3, Sm2O3, MgO, and SrCO3, mixing them, and then sequentially subjecting them to wet ball milling and drying. Finally, the mixture was calcined at 900–1100℃ for 2–4 hours to obtain (CaCO3)2O3. 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 Calcinated TiO3 powder;

[0015] Step 2, for (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 calcined powder, (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 )TiO3 calcined powder and (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 The calcined TiO3 powder was subjected to wet ball milling, drying, and sieving to obtain (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 sieved material, (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 sieved material and (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 sieved material;

[0016] Step 3: First, separate (Ca) 0.2 Li 0.2 Sm 0.2Mg 0.2 Zn 0.2 TiO3 sieved material, (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 sieved material and (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 sieved material is pressed into green blanks, and then cold isostatically pressed into ceramic discs. The ceramic discs are then transferred to a muffle furnace and heated from room temperature to 1250–1375°C at a rate of 3–5°C / min, held at that temperature for 150–240 min, and then cooled to 500°C at a rate of 3–5°C / min. Finally, the temperature is cooled to room temperature with the furnace to obtain dense high-entropy perovskite microwave dielectric ceramics.

[0017] Furthermore, the purity of CaCO3, Li2CO3, Sm2O3, MgO, ZnO, BaCO3, and SrCO3 in step 1 is all greater than 98%.

[0018] Further, the wet ball milling process in steps 1 and 2 is as follows: the material, zirconium balls and liquid are added to a planetary ball mill at a mass ratio of 1:(4-6):(0.8-1.4) and milled for 10-24 hours at a speed of 300-500 r / min, wherein: the zirconium balls are made by mixing small, medium and large zirconium balls at a mass ratio of 1:(3-5):1; the liquid is deionized water or anhydrous ethanol.

[0019] Furthermore, the drying in steps 1 and 2 is carried out at 80–100°C for 12–36 hours.

[0020] Furthermore, the sieving in step 2 is done through a 120-300 mesh sieve.

[0021] Furthermore, the cooling and pressing process in step 3 is as follows: first, pressurize at a rate of 20-40 MPa / min, then hold at 120-250 MPa for 3-10 minutes, and then depressurize at a rate of 20-40 MPa / min.

[0022] Furthermore, the green blank in step 3 is a thin sheet with a thickness of 2-7 mm and a diameter of 10-14 mm.

[0023] Application of a high-entropy perovskite microwave dielectric ceramic with medium to high dielectric constant in microwave antennas and 6G base stations.

[0024] The present invention has the following beneficial technical effects:

[0025] This invention, by combining high-entropy ceramics and perovskite-structured microwave dielectric ceramics, and through a directional composition selection strategy, can synergistically optimize the dielectric constant, quality factor, and resonant frequency temperature stability of the microwave dielectric ceramics, thereby improving the high-entropy perovskite microwave dielectric ceramic (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Me 0.2 TiO3 has a microwave dielectric constant of 50–115, a quality factor of 2000–11000 GHz, and a resonant frequency temperature coefficient of 40–140 ppm / ℃, exhibiting excellent microwave dielectric properties that can meet the needs of the mobile communication field for high-performance, miniaturized, and highly reliable microwave devices.

[0026] This invention successfully prepared high-entropy perovskite microwave dielectric ceramics with medium-high dielectric properties and single-phase or multi-phase structures by controlling the phase structure through ball milling parameters, calcination regime, and sintering regime. Moreover, the preparation process is simple, green and environmentally friendly, and the sintering temperature is effectively reduced without adding sintering aids. This provides a new approach to the construction of novel microwave dielectric ceramics and is of great significance for promoting the application of perovskite structure microwave dielectric ceramics in microwave antennas and 6G base stations in the field of mobile communication. Attached Figure Description

[0027] Figure 1 The XRD patterns of the high-entropy perovskite microwave dielectric ceramics synthesized in Examples 1 to 3 of this invention are shown below.

[0028] Figure 2 SEM image of the high-entropy perovskite microwave dielectric ceramic synthesized in Example 1 of the invention;

[0029] Figure 3 The bar chart shows the dielectric constants of the high-entropy perovskite microwave dielectric ceramics synthesized in Examples 1 to 3 of this invention.

[0030] Figure 4 This is a bar chart showing the quality factor of the high-entropy perovskite microwave dielectric ceramics synthesized in Examples 1 to 3 of the present invention.

[0031] Figure 5 This is a bar chart showing the temperature coefficient of the resonant frequency of the high-entropy perovskite microwave dielectric ceramics synthesized in Examples 1 to 3 of the present invention. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0033] The purity of CaCO3, Li2CO3, Sm2O3, MgO, ZnO, BaCO3 and SrCO3 selected in Examples 1 to 6 of this invention is all greater than 98%.

[0034] Example 1

[0035] Step 1: First, follow the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 was prepared by weighing and mixing CaCO3, Li2CO3, Sm2O3, MgO, and ZnO to obtain a mixture. Small, medium, and large-sized zirconium balls were then mixed at a mass ratio of 1:5:1. The mixture, zirconium balls, and deionized water were then added to a planetary ball mill at a mass ratio of 1:6:1 and milled for 10 hours at 390 r / min. The mixture was then dried at 80℃ for 24 hours and calcined at 800℃ for 4 hours to obtain (CaCO3, Li2CO3, Sm2O3, MgO, and ZnO). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 Calcinated TiO3 powder;

[0036] Step 2: First, mix small, medium, and large-sized zirconium spheres at a mass ratio of 1:3:1, then mix them at a mass ratio of 1:5:1. (Ca...) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 calcined powder, zirconium balls, and deionized water were added to a planetary ball mill and ball-milled at 400 r / min for 18 h. Then, the powder was dried at 80 °C for 36 h and passed through a 200-mesh sieve to obtain (Ca). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 sieved material;

[0037] Step 3, (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 sieved material is pressed into a sheet with a thickness of 2 mm and a diameter of 14 mm, and then subjected to cold pressing. The specific process is as follows: first, pressure is applied at a rate of 40 MPa / min, then pressure is maintained at 200 MPa for 3 min, and then pressure is released at a rate of 40 MPa / min to obtain ceramic discs.

[0038] Step 4: Place the ceramic disc into an alumina crucible with sieved material as a backing plate, and place it in a muffle furnace. Heat the ceramic disc from room temperature to 1250°C at a rate of 3°C / min, hold it at that temperature for 210 min, then cool it down to 500°C at a rate of 5°C / min, and finally cool it to room temperature with the furnace to obtain a dense high-entropy perovskite microwave dielectric ceramic.

[0039] Example 2

[0040] Step 1: First, follow the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 was prepared by weighing and mixing CaCO3, Li2CO3, Sm2O3, MgO, and BaCO3 to obtain a mixture. Small, medium, and large-sized zirconium balls were then mixed at a mass ratio of 1:4:1. The mixture, zirconium balls, and deionized water were then added to a planetary ball mill at a mass ratio of 1:5:1 and milled for 12 hours at 400 r / min. The mixture was then dried at 90℃ for 12 hours and calcined at 850℃ for 4 hours to obtain (CaO3). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 Calcinated TiO3 powder;

[0041] Step 2: First, mix small, medium, and large-sized zirconium spheres at a mass ratio of 1:4:1, then mix them at a mass ratio of 1:5:1. 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 calcined powder, zirconium balls, and deionized water were added to a planetary ball mill and ball-milled at 400 r / min for 16 h. Then, the mixture was dried at 90 °C for 18 h and passed through a 150-mesh sieve to obtain (Ca). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 sieved material;

[0042] Step 3, (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2TiO3 sieved material is pressed into a sheet with a thickness of 4 mm and a diameter of 12 mm, and then subjected to cold pressing. The specific process is as follows: first, pressure is applied at a rate of 25 MPa / min, then pressure is maintained at 120 MPa for 5 min, and then pressure is released at a rate of 25 MPa / min to obtain ceramic discs.

[0043] Step 4: Place the ceramic disc into an alumina crucible with sieved material as a backing plate, and place it in a muffle furnace. Heat the ceramic disc from room temperature to 1300℃ at a rate of 5℃ / min, hold it at that temperature for 150min, then cool it down to 500℃ at a rate of 3℃ / min, and finally cool it down to room temperature with the furnace to obtain a dense high-entropy perovskite microwave dielectric ceramic.

[0044] Example 3

[0045] Step 1: First, follow the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 was prepared by weighing and mixing CaCO3, Li2CO3, Sm2O3, MgO, and SrCO3 to obtain a mixture. Small, medium, and large-sized zirconium balls were then mixed at a mass ratio of 1:3.5:1. The mixture, zirconium balls, and deionized water were then added to a planetary ball mill at a mass ratio of 1:4:1 and milled for 15 hours at 400 rpm. The mixture was then dried at 90°C for 14 hours and calcined at 900°C for 4 hours to obtain (CaO3). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 Calcinated TiO3 powder;

[0046] Step 2: First, mix small, medium, and large-sized zirconium spheres at a mass ratio of 1:3:1, then mix them at a mass ratio of 1:5:1. (Ca...) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 calcined powder, zirconium balls, and deionized water were added to a planetary ball mill and ball-milled at 400 r / min for 18 h. Then, the mixture was dried at 80 °C for 24 h and passed through a 150-mesh sieve to obtain (Ca). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 sieved material;

[0047] Step 3, (Ca) 0.2 Li 0.2 Sm0.2 Mg 0.2 Sr 0.2 TiO3 sieved material is pressed into a sheet with a thickness of 7 mm and a diameter of 10 mm, and then subjected to cold pressing. The specific process is as follows: first, pressure is applied at a rate of 20 MPa / min, then pressure is maintained at 150 MPa for 5 min, and then pressure is released at a rate of 40 MPa / min to obtain ceramic discs.

[0048] Step 4: Place the ceramic disc into an alumina crucible with sieved material as a backing plate, and place it in a muffle furnace. Heat the ceramic disc from room temperature to 1375°C at a rate of 3°C / min, hold it at that temperature for 180 min, then cool it down to 500°C at a rate of 3°C / min, and finally cool it to room temperature with the furnace to obtain a dense high-entropy perovskite microwave dielectric ceramic.

[0049] Example 4

[0050] Step 1: First, follow the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 was prepared by weighing and mixing CaCO3, Li2CO3, Sm2O3, MgO, and ZnO to obtain a mixture. Small, medium, and large-sized zirconium balls were then mixed at a mass ratio of 1:3:1. The mixture, zirconium balls, and deionized water were then added to a planetary ball mill at a mass ratio of 1:6:1.4 and milled for 20 hours at 300 r / min. The mixture was then dried at 100℃ for 16 hours and calcined at 875℃ for 2 hours to obtain (CaCO3, Li2CO3, Sm2O3, MgO, and ZnO). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 Calcinated TiO3 powder;

[0051] Step 2: First, mix small, medium, and large-sized zirconium spheres at a mass ratio of 1:5:1, then mix them at a mass ratio of 1:4:0.8, adding (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 calcined powder, zirconium balls, and deionized water were added to a planetary ball mill and ball-milled at 300 r / min for 20 h. Then, the mixture was dried at 100 °C for 16 h and passed through a 120-mesh sieve to obtain (Ca). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 sieved material;

[0052] Step 3, (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 sieved material is pressed into a sheet with a thickness of 5 mm and a diameter of 12 mm, and then subjected to cold pressing. The specific process is as follows: first, pressure is applied at a rate of 30 MPa / min, then pressure is maintained at 250 MPa for 6 min, and then pressure is released at a rate of 30 MPa / min to obtain ceramic discs.

[0053] Step 4: Place the ceramic disc into an alumina crucible with sieved material as a backing plate, and place it in a muffle furnace. Heat the ceramic disc from room temperature to 1275°C at a rate of 4°C / min, hold it at that temperature for 240 min, then cool it down to 500°C at a rate of 4°C / min, and finally cool it to room temperature with the furnace to obtain a dense high-entropy perovskite microwave dielectric ceramic.

[0054] Example 5

[0055] Step 1: First, follow the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 was prepared by weighing and mixing CaCO3, Li2CO3, Sm2O3, MgO, and BaCO3 to obtain a mixture. Small, medium, and large-sized zirconium balls were then mixed at a mass ratio of 1:4:1. The mixture, zirconium balls, and anhydrous ethanol were then added to a planetary ball mill at a mass ratio of 1:5:1.1 and milled for 24 hours at 400 r / min. The mixture was then dried at 80℃ for 24 hours and calcined at 975℃ for 3 hours to obtain (CaO3). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 Calcinated TiO3 powder;

[0056] Step 2: First, mix small, medium, and large-sized zirconium spheres at a mass ratio of 1:4:1, then mix them at a mass ratio of 1:5:1.1, adding (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 calcined powder, zirconium balls, and anhydrous ethanol were added to a planetary ball mill and ball-milled at 400 r / min for 24 h. Then, the mixture was dried at 80 °C for 30 h and passed through a 250-mesh sieve to obtain (Ca). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba0.2 TiO3 sieved material;

[0057] Step 3, (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 sieved material is pressed into a sheet with a thickness of 3 mm and a diameter of 13 mm, and then subjected to cold pressing. The specific process is as follows: first, pressure is applied at a rate of 35 MPa / min, then pressure is maintained at 150 MPa for 10 min, and then pressure is released at a rate of 35 MPa / min to obtain ceramic discs.

[0058] Step 4: Place the ceramic disc into an alumina crucible with sieved material as a backing plate, and place it in a muffle furnace. Heat the ceramic disc from room temperature to 1275°C at a rate of 3°C / min, hold it at that temperature for 180 min, then cool it down to 500°C at a rate of 3°C / min, and finally cool it to room temperature with the furnace to obtain a dense high-entropy perovskite microwave dielectric ceramic.

[0059] Example 6

[0060] Step 1: First, follow the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 was prepared by weighing and mixing CaCO3, Li2CO3, Sm2O3, MgO, and SrCO3 to obtain a mixture. Small, medium, and large-sized zirconium balls were then mixed at a mass ratio of 1:3.5:1. The mixture, zirconium balls, and anhydrous ethanol were then added to a planetary ball mill at a mass ratio of 1:4:0.8 and milled for 22 hours at 500 r / min. The mixture was then dried at 80℃ for 20 hours and calcined at 1025℃ for 3 hours to obtain (CaO3). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 Calcinated TiO3 powder;

[0061] Step 2: First, mix small, medium, and large-sized zirconium spheres at a mass ratio of 1:3:1, then mix them at a mass ratio of 1:6:1.4, adding (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 calcined powder, zirconium balls, and anhydrous ethanol were added to a planetary ball mill and ball-milled at 500 r / min for 10 h. Then, the mixture was dried at 100 °C for 16 h and passed through a 300-mesh sieve to obtain (Ca... 0.2 Li0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 sieved material;

[0062] Step 3, (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 sieved material is pressed into a sheet with a thickness of 6 mm and a diameter of 11 mm, and then subjected to cold pressing. The specific process is as follows: first, pressure is applied at a rate of 40 MPa / min, then pressure is maintained at 200 MPa for 4 min, and then pressure is released at a rate of 20 MPa / min to obtain ceramic discs.

[0063] Step 4: Place the ceramic disc into an alumina crucible with sieved material as a backing plate, and place it in a muffle furnace. Heat the ceramic disc from room temperature to 1375°C at a rate of 5°C / min, hold it at that temperature for 240 min, then cool it down to 500°C at a rate of 3°C / min, and finally cool it down to room temperature with the furnace to obtain a dense high-entropy perovskite microwave dielectric ceramic.

[0064] Example 7

[0065] Step 1: First, follow the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 was prepared by weighing and mixing CaCO3, Li2CO3, Sm2O3, MgO, and ZnO to obtain a mixture. Small, medium, and large-sized zirconium balls were then mixed at a mass ratio of 1:5:1. The mixture, zirconium balls, and deionized water were then added to a planetary ball mill at a mass ratio of 1:6:1 and milled for 10 hours at 390 r / min. The mixture was then dried at 80℃ for 28 hours and calcined at 1000℃ for 3 hours to obtain (CaCO3, Li2CO3, Sm2O3, MgO, and ZnO). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 Calcinated TiO3 powder;

[0066] Step 2: First, mix small, medium, and large-sized zirconium spheres at a mass ratio of 1:3:1, then mix them at a mass ratio of 1:5:1. (Ca...) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2TiO3 calcined powder, zirconium balls, and deionized water were added to a planetary ball mill and ball-milled at 400 r / min for 12 h. Then, the mixture was dried at 80 °C for 28 h and passed through a 200-mesh sieve to obtain (Ca). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 sieved material;

[0067] Step 3, (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 sieved material is pressed into a sheet with a thickness of 2 mm and a diameter of 14 mm, and then subjected to cold pressing. The specific process is as follows: first, pressure is applied at a rate of 40 MPa / min, then pressure is maintained at 200 MPa for 9 min, and then pressure is released at a rate of 40 MPa / min to obtain ceramic discs.

[0068] Step 4: Place the ceramic disc into an alumina crucible with sieved material as a backing plate, and place it in a muffle furnace. Heat the ceramic disc from room temperature to 1250°C at a rate of 3°C / min, hold it at that temperature for 210 min, then cool it down to 500°C at a rate of 5°C / min, and finally cool it to room temperature with the furnace to obtain a dense high-entropy perovskite microwave dielectric ceramic.

[0069] Example 8

[0070] Step 1: First, follow the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 was prepared by weighing and mixing CaCO3, Li2CO3, Sm2O3, MgO, and BaCO3 to obtain a mixture. Small, medium, and large-sized zirconium balls were then mixed at a mass ratio of 1:4:1. The mixture, zirconium balls, and deionized water were then added to a planetary ball mill at a mass ratio of 1:5:1 and milled for 12 hours at 400 r / min. The mixture was then dried at 90℃ for 32 hours and calcined at 1050℃ for 2 hours to obtain (CaO3). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 Calcinated TiO3 powder;

[0071] Step 2: First, mix small, medium, and large-sized zirconium spheres at a mass ratio of 1:4:1, then mix them at a mass ratio of 1:5:1. 0.2 Li 0.2 Sm0.2 Mg 0.2 Ba 0.2 TiO3 calcined powder, zirconium balls, and deionized water were added to a planetary ball mill and ball-milled at 400 r / min for 14 h. Then, the powder was dried at 90 °C for 12 h and passed through a 150-mesh sieve to obtain (Ca). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 sieved material;

[0072] Step 3, (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 sieved material is pressed into a sheet with a thickness of 4 mm and a diameter of 12 mm, and then subjected to cold pressing. The specific process is as follows: first, pressure is applied at a rate of 25 MPa / min, then pressure is maintained at 120 MPa for 8 min, and then pressure is released at a rate of 25 MPa / min to obtain ceramic discs.

[0073] Step 4: Place the ceramic disc into an alumina crucible with sieved material as a backing plate, and place it in a muffle furnace. Heat the ceramic disc from room temperature to 1300℃ at a rate of 5℃ / min, hold it at that temperature for 150min, then cool it down to 500℃ at a rate of 3℃ / min, and finally cool it down to room temperature with the furnace to obtain a dense high-entropy perovskite microwave dielectric ceramic.

[0074] Example 9

[0075] Step 1: First, follow the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 was prepared by weighing and mixing CaCO3, Li2CO3, Sm2O3, MgO, and SrCO3 to obtain a mixture. Small, medium, and large-sized zirconium balls were then mixed at a mass ratio of 1:3.5:1. The mixture, zirconium balls, and deionized water were then added to a planetary ball mill at a mass ratio of 1:4:1 and milled for 15 hours at 400 r / min. The mixture was then dried at 90℃ for 36 hours and calcined at 1100℃ for 2 hours to obtain (CaO3). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 Calcinated TiO3 powder;

[0076] Step 2: First, mix small, medium, and large-sized zirconium spheres at a mass ratio of 1:3:1, then mix them at a mass ratio of 1:5:1. (Ca...) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 calcined powder, zirconium balls, and deionized water were added to a planetary ball mill and ball-milled at 300 r / min for 22 h. Then, the mixture was dried at 80 °C for 20 h and passed through a 150-mesh sieve to obtain (Ca). 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 sieved material;

[0077] Step 3, (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 sieved material is pressed into a sheet with a thickness of 7 mm and a diameter of 10 mm, and then subjected to cold pressing. The specific process is as follows: first, pressure is applied at a rate of 20 MPa / min, then pressure is maintained at 150 MPa for 7 min, and then pressure is released at a rate of 40 MPa / min to obtain ceramic discs.

[0078] Step 4: Place the ceramic disc into an alumina crucible with sieved material as a backing plate, and place it in a muffle furnace. Heat the ceramic disc from room temperature to 1350°C at a rate of 3°C / min, hold it at that temperature for 200 min, then cool it down to 500°C at a rate of 3°C / min, and finally cool it down to room temperature with the furnace to obtain a dense high-entropy perovskite microwave dielectric ceramic.

[0079] from Figure 1 It can be seen that the high-entropy perovskite microwave dielectric ceramic prepared in Example 1 is a composite structure of CaTiO3 and Zn2Ti3O8; the high-entropy perovskite microwave dielectric ceramic prepared in Example 2 is a composite structure of CaTiO3 and BaTiO3; and the high-entropy perovskite microwave dielectric ceramic prepared in Example 3 is a single-phase structure of CaTiO3.

[0080] from Figure 2 It can be seen that the high-entropy perovskite microwave dielectric ceramic (Ca) prepared in Example 1... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 has different grains and a multiphase structure, which is beneficial for simultaneously obtaining the high dielectric constant of CaTiO3 and the high quality factor and low resonant frequency temperature coefficient of Zn2Ti3O8.

[0081] The high-entropy perovskite microwave dielectric ceramics prepared in Examples 1-3 were ultrasonically cleaned, dried, and then subjected to microwave dielectric property testing. The results are as follows: Figures 3-5 As shown:

[0082] from Figure 3 It can be seen that the microwave dielectric constants of the high-entropy perovskite microwave dielectric ceramics prepared in Examples 1 to 3 are 50–115. Among them, the high-entropy perovskite microwave dielectric ceramic (Ca) prepared in Example 3 has a higher dielectric constant. 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 has a microwave dielectric constant as high as 115;

[0083] from Figure 4 It can be seen that the quality factors of the high-entropy perovskite microwave dielectric ceramics prepared in Examples 1 to 3 are 2000–11000 GHz. Among them, the high-entropy perovskite microwave dielectric ceramic (Ca) prepared in Example 1 has a quality factor of 2000–11000 GHz. 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 has a quality factor as high as 11000 GHz.

[0084] from Figure 5 It can be seen that the resonant frequency temperature coefficients of the high-entropy perovskite microwave dielectric ceramics prepared in Examples 1 to 3 are 40–140 ppm / ℃. Among them, the high-entropy perovskite microwave dielectric ceramic (Ca) prepared in Example 1 has a resonant frequency temperature coefficient of 40–140 ppm / ℃. 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 The temperature coefficient of the resonant frequency of TiO3 is 40 ppm / ℃;

[0085] In summary, the high-entropy perovskite microwave dielectric ceramic prepared by this invention has a high dielectric constant, while maintaining a high quality factor and a low temperature coefficient of resonant frequency, exhibiting excellent microwave dielectric properties.

Claims

1. A high-entropy perovskite microwave dielectric ceramic with medium to high dielectric constant, characterized in that, The stoichiometric formula is: (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Me 0.2 TiO3, wherein Me is Zn, Ba or Sr; microwave dielectric constant is 50 to 115, quality factor is 2000 to 11000 GHz, and resonant frequency temperature coefficient is 40 to 140 ppm / ℃.

2. The high-entropy perovskite microwave dielectric ceramic with medium to high dielectric constant according to claim 1, characterized in that, The chemical formula is (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 has a microwave dielectric constant of 50, a quality factor of 11000 GHz, and a resonant frequency temperature coefficient of 40 ppm / ℃.

3. A method for preparing a high-entropy perovskite microwave dielectric ceramic with medium to high dielectric constant, characterized in that, Includes the following steps: Step 1, Preparation of (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Me 0.2 The specific process for calcining TiO3 powder is as follows: When Me is Zn, according to the stoichiometric formula (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 was prepared by weighing out CaCO3, Li2CO3, Sm2O3, MgO, and ZnO, mixing them, and then sequentially subjecting them to wet ball milling and drying. Finally, the mixture was calcined at 800–1000℃ for 2–4 hours to obtain (CaCO3)2O3. 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 Calcinated TiO3 powder; When Me is Ba, according to the stoichiometric formula (Ca... 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 was prepared by weighing out CaCO3, Li2CO3, Sm2O3, MgO, and BaCO3, mixing them, and then sequentially subjecting them to wet ball milling and drying. Finally, the mixture was calcined at 850–1050 °C for 2–4 hours to obtain (CaCO3)2O3. 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 Calcinated TiO3 powder; When Me is Sr, according to the stoichiometric formula (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 was prepared by weighing out CaCO3, Li2CO3, Sm2O3, MgO, and SrCO3, mixing them, and then sequentially subjecting them to wet ball milling and drying. Finally, the mixture was calcined at 900–1100℃ for 2–4 hours to obtain (CaCO3)2O3. 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 Calcinated TiO3 powder; Step 2, for (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 calcined powder, (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 )TiO3 calcined powder and (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 The calcined TiO3 powder was subjected to wet ball milling, drying, and sieving to obtain (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 sieved material, (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 sieved material and (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 sieved material; Step 3: First, separate (Ca) 0.2 Li 0.2 Sm 0.2 Mg 0.2 Zn 0.2 TiO3 sieved material, (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Ba 0.2 TiO3 sieved material and (Ca 0.2 Li 0.2 Sm 0.2 Mg 0.2 Sr 0.2 TiO3 sieved material is pressed into green blanks, and then cold isostatically pressed into ceramic discs. The ceramic discs are then transferred to a muffle furnace and heated from room temperature to 1250–1375°C at a rate of 3–5°C / min, held at that temperature for 150–240 min, and then cooled to 500°C at a rate of 3–5°C / min. Finally, the temperature is cooled to room temperature with the furnace to obtain dense high-entropy perovskite microwave dielectric ceramics.

4. The method for preparing high-entropy perovskite microwave dielectric ceramics with medium to high dielectric constant according to claim 3, characterized in that, The purity of CaCO3, Li2CO3, Sm2O3, MgO, ZnO, BaCO3 and SrCO3 in step 1 is all greater than 98%.

5. The method for preparing high-entropy perovskite microwave dielectric ceramics with medium to high dielectric constant according to claim 3, characterized in that, The wet ball milling process in steps 1 and 2 is as follows: the material, zirconium balls and liquid are added to a planetary ball mill at a mass ratio of 1:(4-6):(0.8-1.4) and milled for 10-24 hours at a speed of 300-500 r / min. The zirconium balls are made by mixing small, medium and large zirconium balls at a mass ratio of 1:(3-5):

1. The liquid is deionized water or anhydrous ethanol.

6. The method for preparing high-entropy perovskite microwave dielectric ceramics with medium to high dielectric constant according to claim 3, characterized in that, The drying in steps 1 and 2 is carried out at 80-100°C for 12-36 hours.

7. The method for preparing high-entropy perovskite microwave dielectric ceramics with medium to high dielectric constant according to claim 3, characterized in that, The sieving in step 2 involves passing the material through a 120-300 mesh sieve.

8. The method for preparing high-entropy perovskite microwave dielectric ceramics with medium to high dielectric constant according to claim 3, characterized in that, The cooling and pressing process in step 3 is as follows: first, pressurize at a rate of 20-40 MPa / min, then hold at 120-250 MPa for 3-10 minutes, and then depressurize at a rate of 20-40 MPa / min.

9. The method for preparing high-entropy perovskite microwave dielectric ceramics with medium to high dielectric constant according to claim 3, characterized in that, The green blank in step 3 is a thin sheet with a thickness of 2-7 mm and a diameter of 10-14 mm.

10. The application of a high-entropy perovskite microwave dielectric ceramic with medium to high dielectric constant as described in claim 1 or 2 in microwave antennas and 6G base stations.

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