Perovskite high-entropy ceramic material with excellent dielectric temperature stability and preparation method

Abstract

This application discloses a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability. The chemical formula of the high-entropy ceramic material is (Ca... 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zr x O3, x=0.05~0.2. This application employs an A-site high-entropy material composition design that enables elements to break through the solid solution limit, achieving greater solid solubility in the material system. By using Zr 2+ Ti at the B site in ion-substituted ceramics 2+ The composition design approach successfully achieved B-site ion doping, resulting in well-grown, dense grains within the ceramic. The sample microstructure exhibited few pores, with elements uniformly distributed throughout the ceramic without agglomeration. By optimizing and controlling the ceramic's microstructure, the dielectric ceramic obtained in this application possesses a high dielectric constant and excellent temperature stability, with capacitance-temperature variations meeting both X7R and X6R capacitor standards.

Description

Technical Field

[0001] This application belongs to the field of inorganic non-metallic functional materials technology, specifically relating to a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability and its preparation method. Background Technology

[0002] With the rapid development of high-performance energy storage systems and other fields towards high temperature, high frequency, and high precision, stringent requirements are being placed on the comprehensive performance of dielectric ceramic materials. As a core functional component of various electronic devices, the temperature stability of the dielectric constant and the low-loss characteristics at high temperatures determine the reliability, lifespan, and energy conversion efficiency of these devices in complex operating environments. Especially in applications such as power modules for new energy vehicles and pulsed power systems, materials need to withstand long-term fluctuations over a wide temperature range. Traditional dielectric ceramics struggle to meet the dual requirements of "stable dielectric performance + high temperature and low loss," making the development of high-performance dielectric ceramics with excellent dielectric temperature stability one of the current research hotspots in the materials field.

[0003] High-entropy engineering constructs high configurational entropy systems through the synergistic doping of multiple elements, utilizing its unique high-entropy effect, lattice distortion effect, hysteresis diffusion effect, and cocktail effect to provide a novel approach for optimizing the microstructure and functional properties of materials. Since the concept of high entropy expanded from the alloy field to ceramic materials, high-entropy dielectric ceramics have rapidly become a research hotspot in the field of dielectric materials due to their advantages such as potentially huge dielectric constants, excellent thermal stability, and structural tunability. Compared with traditional single-component or low-component dielectric ceramics, high-entropy dielectric ceramics can effectively control the lattice structure, defect distribution, and micromorphology through the synergistic effect of multiple cations, thereby optimizing dielectric properties. Simultaneously, research shows that doping cations at the B-site can increase the disorder and complexity within the oxygen octahedron, which is beneficial for improving energy storage performance and dielectric properties.

[0004] The invention disclosed in CN 112723881 B is a dielectric ceramic material with high temperature stability, achieved by selecting a positive temperature coefficient material (Bi). 0.9 La 0.1 )2Ti2O7 and negative temperature coefficient materials CaBi4Ti4O 15 Composites are used to achieve high dielectric constant and excellent temperature stability.

[0005] The invention disclosed in CN 118359431 A is a barium titanate-based dielectric ceramic material with high energy conversion efficiency and high temperature stability, and its preparation method, which significantly improves energy storage efficiency. Its general chemical formula is (1-x)Ba(Ti 0.8 Sn 0.2 )O3-xBi(Mg 0.5 Hf0.5 O3, of which 0 <x≤0.35。

[0006] The invention disclosed in CN 118545994 A is a lead-free, environmentally friendly sodium bismuth titanate-based composite dielectric energy storage ceramic with excellent dielectric temperature stability prepared by rapid sintering technology, as well as its preparation method and application. Its dielectric temperature stability meets the requirements for use in X9R capacitors. The general chemical composition is (100-xy)mol%Na. 0.5 Bi 0.5 TiO3-xmol%K 0.5 Bi 0.5 TiO3-ymol%Sr 0.25 Ca 0.25 Na 0.25 Bi 0.25 Ti 0.69 Zr 0.14 Sn 0.17 O3-zwt%MeF2, 18<x<22.9, 5.9<y<9.5, 4.6<z<6.7, Me = any one of Ca, Sr, or Ba.

[0007] However, existing material systems cannot simultaneously achieve a synergistic improvement in high dielectric constant, low dielectric loss, and excellent dielectric temperature stability over a wide temperature range. Summary of the Invention

[0008] This invention aims to provide a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability and its preparation method, through A-site high-entropy design and B-site Zr 2+ Doping enables the simultaneous achievement of high dielectric constant, low dielectric loss, and capacitance-temperature change rate over a wide temperature range, meeting the X7R or X6R capacitor standards.

[0009] To achieve the above technical objectives, this application specifically adopts the following technical solution: In one aspect of this application, a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability is provided, wherein the chemical formula of the high-entropy ceramic material is (Ca... 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zr x O3, where x = 0.05~0.2.

[0010] In one implementation, the value of x is 0.05, 0.1, 0.15, or 0.2.

[0011] In one embodiment, the raw materials for synthesizing the high-entropy ceramic material are CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2 and TiO2, all of which are analytical grade and have micron-sized particles.

[0012] In another aspect of this application, a method for preparing a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability is provided, comprising the following steps: Step 1, Ingredients: According to (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zr x The stoichiometric ratio of the raw materials CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2 and TiO2 was weighed out. Step 2, Preparation of mixed powder: The weighed raw materials are mixed with ball milling beads and anhydrous ethanol, then ball milled, dried and ground to obtain mixed powder; Step 3, Pre-synthesized powder: The mixed powder is placed in a crucible and pre-synthesized at 1225℃~1275℃ for 2~4 hours. After cooling, the pre-synthesized powder is obtained. Step 4, Granulation and pressing: Add binder to the pre-synthesized powder, mix and sieve, take 50-100 mesh particles and press them into ceramic blanks; Step 5, Debinding: The ceramic green body is heated to 650°C to debind, resulting in a ceramic green body; Step 6, sintering: The ceramic green body is sintered at 1225℃~1275℃ and held for 2~4h. After cooling, the perovskite structure high-entropy ceramic material with excellent dielectric temperature stability is obtained.

[0013] In one embodiment, the ball milling time in step 2 is 8 to 12 hours, the drying temperature is 50°C to 60°C, and the drying time is 3 to 12 hours.

[0014] In one embodiment, in steps 3 and 6, the temperature is increased to 1225°C to 1275°C at a heating rate of 5°C / min, and after holding at that temperature, the temperature is reduced to 500°C at a cooling rate of 2°C / min to 5°C / min, and then cooled with the furnace.

[0015] In one embodiment, the pressing pressure of the ceramic blank in step 4 is 2MPa to 5MPa.

[0016] In one embodiment, in step 5, the temperature is increased to 650°C at a heating rate of 0.5°C / min to 1°C / min for debinding.

[0017] The beneficial effects of this application are as follows: Compared with existing technologies, the provided high-entropy ceramic material has the chemical formula (Ca... 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zr x O3. This application employs an A-site high-entropy material composition design that enables elements to exceed the solid solution limit, achieving greater solid solubility in the material system. By using Zr... 2+ Ti at the B site in ion-substituted ceramics 2+ Following the compositional design approach, B-site ion doping was successfully achieved, resulting in a single-phase solid solution ceramic. The ceramic exhibits dense grain growth, few pores, and uniform distribution of Ca, Sr, Ba, Mg, Bi, Na, Ti, and Zr elements. Dielectric temperature spectroscopy analysis shows that the high-entropy ceramic material of this application... Internal temperature change rate over a wide temperature range of 45-90℃ |△ε| / ε 25 ≤10%, meeting the X7R and X6R standards while maintaining a high dielectric constant and low dielectric loss. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the preparation process of the perovskite-structured high-entropy ceramic material of this application; Figure 2 This is an X-ray diffraction pattern of a high-entropy ceramic material according to an embodiment of this application; where 1 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.95 Zr 0.05 X-ray diffraction pattern of O3; 2 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.90 Zr 0.10 X-ray diffraction pattern of O3; 3 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi0.1 Na 0.1 (Ti) 0.85 Zr 0.15 X-ray diffraction pattern of O3; 4 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.80 Zr 0.20 X-ray diffraction pattern of O3; Figure 3 This is a SEM image of the perovskite-structured high-entropy ceramic material from Example 1 of this application, along with a schematic diagram of the elemental distribution within the ceramic; where a is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.95 Zr 0.05 SEM morphology of O3 ceramic surface: b is a schematic diagram of Ca distribution in ceramic, c is a schematic diagram of Sr distribution in ceramic, d is a schematic diagram of Ba distribution in ceramic, e is a schematic diagram of Mg distribution in ceramic, f is a schematic diagram of Bi distribution in ceramic, g is a schematic diagram of Ti distribution in ceramic, and h is a schematic diagram of Zr distribution in ceramic. Figure 4 This is a SEM image of the perovskite-structured high-entropy ceramic material from Example 2 of this application, along with a schematic diagram of the elemental distribution within the ceramic; where a is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.90 Zr 0.10 SEM morphology of O3 ceramic surface: b is a schematic diagram of Ca distribution in ceramic, c is a schematic diagram of Sr distribution in ceramic, d is a schematic diagram of Ba distribution in ceramic, e is a schematic diagram of Mg distribution in ceramic, f is a schematic diagram of Bi distribution in ceramic, g is a schematic diagram of Ti distribution in ceramic, and h is a schematic diagram of Zr distribution in ceramic. Figure 5 This is a SEM image of the perovskite-structured high-entropy ceramic material from Example 3 of this application, along with a schematic diagram of the elemental distribution within the ceramic; where a is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.85Zr 0.15 SEM morphology of O3 ceramic surface: b is a schematic diagram of Ca distribution in ceramic, c is a schematic diagram of Sr distribution in ceramic, d is a schematic diagram of Ba distribution in ceramic, e is a schematic diagram of Mg distribution in ceramic, f is a schematic diagram of Bi distribution in ceramic, g is a schematic diagram of Ti distribution in ceramic, and h is a schematic diagram of Zr distribution in ceramic. Figure 6 This is a SEM image of the perovskite-structured high-entropy ceramic material from Example 4 of this application, along with a schematic diagram of the elemental distribution within the ceramic; where a is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.80 Zr 0.20 SEM morphology of O3 ceramic surface: b is a schematic diagram of Ca distribution in ceramic, c is a schematic diagram of Sr distribution in ceramic, d is a schematic diagram of Ba distribution in ceramic, e is a schematic diagram of Mg distribution in ceramic, f is a schematic diagram of Bi distribution in ceramic, g is a schematic diagram of Ti distribution in ceramic, and h is a schematic diagram of Zr distribution in ceramic. Figure 7 This is the dielectric temperature spectrum of a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability, made from CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2, and TiO2, according to this application. In this spectrum, a is the curve showing the change of the ceramic dielectric constant with temperature, and b is the curve showing the change of the ceramic dielectric loss with temperature. In this spectrum, 5 represents (Ca... 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.95 Zr 0.05 The dielectric constant of O3 varies with temperature; 6 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.90 Zr 0.10 The dielectric constant of O3 varies with temperature; 7 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.85 Zr0.15 The dielectric constant of O3 varies with temperature; 8 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.80 Zr 0.20 The dielectric constant of O3 varies with temperature; 9 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.95 Zr 0.05 The dielectric loss curve of O3 versus temperature; 10 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.90 Zr 0.10 The dielectric loss of O3 varies with temperature; 11 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.85 Zr 0.15 The dielectric loss curve of O3 versus temperature; 12 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.80 Zr 0.20 The dielectric loss of O3 as a function of temperature; Figure 8 This is a diagram showing the volumetric temperature change rate of perovskite-structured high-entropy ceramic materials; where 13 represents (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.95 Zr 0.05 The rate of change of volumetric temperature of O3; 14 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1Na 0.1 (Ti) 0.90 Zr 0.10 The rate of change of volumetric temperature of O3; 15 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.85 Zr 0.15 The rate of change of volumetric temperature of O3; 16 is (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.80 Zr 0.20 The rate of change of volumetric temperature of O3. Detailed Implementation

[0019] The technical solution of this application will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this application, not all embodiments, and are only used to illustrate this application, and should not be regarded as limiting the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] Existing dielectric ceramic materials struggle to simultaneously achieve high dielectric constant, low dielectric loss, and capacitive-temperature stability over a wide temperature range. To address these issues, this application proposes introducing equimolar ratios of multiple ions (Ca, Sr, Ba, Mg, Bi, Na) at the A-site to construct a high-entropy perovskite structure, overcoming the single-component solid solution limit. Simultaneously, it utilizes Zr at the B-site... 2+ Partially replaces Ti 2+ Increase the disorder of oxygen octahedrons. Through the synergistic effect of high entropy and lattice distortion, in... A dielectric response with a capacitance-temperature change rate of ≤10% is obtained within the temperature range of 45℃-90℃, while maintaining a dense microstructure and uniform element distribution, thus achieving simultaneous optimization of temperature stability, dielectric constant and loss performance.

[0021] This application discloses a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability, the chemical formula of which is (Ca... 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zrx O3 (x=0.05~0.2).

[0022] Synthesizing the (Ca) 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zr x The raw materials for O3 are CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2 and TiO2, all with micron-sized particles and analytical purity.

[0023] Reference Figure 1 As shown, the preparation of (Ca) 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zr x The specific process of O3 is as follows: Step 1, Ingredients: According to (Ca) 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zr x Weigh the initial raw materials CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2 and TiO2 according to the stoichiometric ratio of the chemical formula of O3.

[0024] Step 2, prepare the mixed powder: Add the initial raw materials weighed in step 1, ZrO2 grinding beads, and anhydrous ethanol to a polytetrafluoroethylene ball mill jar and ball mill for 8-12 hours. The weight ratio of anhydrous ethanol to initial raw materials is 1:1, and the weight ratio of grinding beads to initial raw materials is 2:1. Place the ball-milled slurry in an oven for drying at a temperature of 50-60 ℃ for 3-12 hours. Grind the mixture to obtain a mixed powder.

[0025] Step 3, Preparation of pre-synthesized powder: The mixed powder obtained in step 2 is placed in a sealed crucible and heated to 1225~1275 ℃ in a high-temperature muffle furnace at a heating rate of 5 ℃ / min. After holding at this temperature for 2~4 h, the temperature is reduced to 500 ℃ at a cooling rate of 2~5 ℃ / min and then cooled with the furnace to obtain the pre-synthesized powder.

[0026] Step 4, Granulation and tableting: Add PVA aqueous solution to the obtained pre-synthesized powder, mix well, and then sieve to obtain particles of 50 to 100 mesh.

[0027] The sieved microparticles are placed in a tablet press and pressed into ceramic blanks at 2-5 MPa.

[0028] Step 5, glue removal: The ceramic green body obtained in step 4 is placed in an alumina crucible and then placed in a box furnace. It is heated to 650 ℃ at a heating rate of 0.5~1 ℃ / min to remove the binder. It is then cooled to room temperature with the furnace to obtain the ceramic green body after binder removal.

[0029] Step 6, Sintering: The obtained ceramic green body is placed in an alumina crucible and then placed in a box furnace for sintering.

[0030] During sintering, the furnace is heated to 1225~1275 ℃ at a rate of 5 ℃ / min and held for 2~4 h. After the holding time, the furnace is cooled to 500 ℃ at a rate of 2~5 ℃ / min and then cooled to room temperature.

[0031] The sintered ceramic green body was removed, ground and polished to obtain a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability.

[0032] All reagents used in the embodiments of this application are commercially available products of analytical grade, manufactured by Sinopharm Chemical Reagent Co., Ltd., with a purity of >99.9%.

[0033] Table 1. Components and dosages of each embodiment

[0034] Example 1 This embodiment proposes the preparation of a perovskite-structured high-entropy ceramic material (Ca) with excellent dielectric temperature stability. 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.95 Zr 0.05 The specific process of O3 is as follows: Step 1, Ingredients: According to (Ca) 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.95 Zr 0.05 The initial raw materials CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2, and TiO2 are accurately weighed according to the stoichiometric ratio of the chemical formula O3; the amounts of CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2, and TiO2 are based on (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.95 Zr 0.05 O3 was calculated.

[0035] Step 2, prepare the mixed powder: The initial raw materials weighed in step 1, ZrO2 grinding beads, and anhydrous ethanol were added to a polytetrafluoroethylene grinding jar and ball-milled for 8 hours. The weight ratio of anhydrous ethanol to initial raw materials was 1:1, and the weight ratio of grinding beads to initial raw materials was 2:1. The ball-milled slurry was placed in an oven for drying at 50 ℃ for 12 hours. The mixture was then ground to obtain a mixed powder.

[0036] Step 3, Preparation of pre-synthesized powder: The mixed powder obtained in step 2 was placed in a sealed crucible and heated to 1225 ℃ in a high-temperature muffle furnace at a heating rate of 5 ℃ / min. After holding at this temperature for 4 h, the temperature was reduced to 500 ℃ at a cooling rate of 2 ℃ / min and then cooled with the furnace to obtain the pre-synthesized powder.

[0037] Step 4, Granulation and tableting: PVA aqueous solution was added to the obtained pre-synthesized powder, mixed evenly, and then sieved to obtain particles of 50 to 100 mesh. The concentration of the PVA aqueous solution (type 1750) was 8 wt%, and the mass ratio of the amount added to the pre-synthesized powder was 1:5.

[0038] The sieved microparticles are placed in a tablet press and pressed at 2 MPa to obtain ceramic green bodies.

[0039] Step 5, glue removal: The ceramic green body obtained in step 4 is placed in an alumina crucible and then placed in a box furnace. It is heated to 650 ℃ at a heating rate of 0.5 ℃ / min to remove the binder. It is then cooled to room temperature with the furnace to obtain the ceramic green body after binder removal.

[0040] Step 6, Sintering: The obtained ceramic green body is placed in an alumina crucible and then placed in a box furnace. The ceramic green body is then sintered.

[0041] During sintering, the furnace is heated to 1225 ℃ at a rate of 5 ℃ / min and held for 4 h. After the holding period, the furnace is cooled to 500 ℃ at a rate of 2 ℃ / min and then cooled to room temperature.

[0042] The sintered ceramic green body was removed, ground and polished to obtain a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability.

[0043] Example 2 This embodiment describes a perovskite-structured high-entropy ceramic material (Ca) with excellent dielectric temperature stability. 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.90 Zr 0.10 The specific process of O3 is as follows: Step 1, Ingredients: According to (Ca) 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.90 Zr 0.10 The initial raw materials CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2, and TiO2 are accurately weighed according to the stoichiometric ratio of the chemical formula O3; the amounts of CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2, and TiO2 are based on (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.90 Zr 0.10 O3 was calculated.

[0044] Step 2, prepare the mixed powder: The initial raw materials weighed in step 1, ZrO2 grinding beads, and anhydrous ethanol were added to a polytetrafluoroethylene grinding jar and ball-milled for 9 hours. The weight ratio of anhydrous ethanol to initial raw materials was 1:1, and the weight ratio of grinding beads to initial raw materials was 2:1. The ball-milled slurry was placed in an oven for drying at 55 ℃ for 10 hours. The mixture was then ground to obtain a mixed powder.

[0045] Step 3, Preparation of pre-synthesized powder: The mixed powder obtained in step 2 was placed in a sealed crucible and heated to 1250 °C in a high-temperature muffle furnace at a heating rate of 5 °C / min. After holding at this temperature for 3 h, the temperature was reduced to 500 °C at a cooling rate of 4 °C / min and then cooled with the furnace to obtain the pre-synthesized powder.

[0046] Step 4, Granulation and tableting: PVA aqueous solution was added to the obtained pre-synthesized powder, mixed evenly, and then sieved to obtain particles of 50 to 100 mesh. The concentration of the PVA aqueous solution (type 1750) was 8 wt%, and the mass ratio of the amount added to the pre-synthesized powder was 1:5.

[0047] The sieved particles are placed in a tablet press and pressed at 4 MPa to obtain a ceramic green body.

[0048] Step 5, glue removal: The ceramic green body obtained in step 4 is placed in an alumina crucible and then placed in a box furnace. It is heated to 650 ℃ at a heating rate of 0.5 ℃ / min to remove the binder. It is then cooled to room temperature with the furnace to obtain the ceramic green body after binder removal.

[0049] Step 6, Sintering: The obtained ceramic green body is placed in an alumina crucible and then placed in a box furnace. The ceramic green body is then sintered.

[0050] During sintering, the furnace is heated to 1250 ℃ at a rate of 5 ℃ / min and held for 3 h. After the holding period, the furnace is cooled to 500 ℃ at a rate of 4 ℃ / min and then cooled to room temperature.

[0051] The sintered ceramic green body was removed, ground and polished to obtain a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability.

[0052] Example 3 This document, number fourteen, describes a perovskite-structured high-entropy ceramic material (Ca) with excellent dielectric temperature stability. 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti)0.85 Zr 0.15 The specific process of O3 is as follows: Step 1, Ingredients: According to (Ca) 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.85 Zr 0.15 The initial raw materials CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2, and TiO2 are accurately weighed according to the stoichiometric ratio of the chemical formula O3; the amounts of CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2, and TiO2 are based on (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.85 Zr 0.15 O3 was calculated.

[0053] Step 2, prepare the mixed powder: The initial raw materials weighed in step 1, ZrO2 grinding beads, and anhydrous ethanol were added to a polytetrafluoroethylene grinding jar and ball-milled for 12 h. The weight ratio of anhydrous ethanol to initial raw materials was 1:1, and the weight ratio of grinding beads to initial raw materials was 2:1. The ball-milled slurry was placed in an oven for drying at 60 ℃ for 6 h. The mixture was then ground to obtain a mixed powder.

[0054] Step 3, Preparation of pre-synthesized powder: The mixed powder obtained in step 2 was placed in a sealed crucible and heated to 1250 ℃ in a high-temperature muffle furnace at a heating rate of 5 ℃ / min. After holding at this temperature for 4 h, the temperature was reduced to 500 ℃ at a cooling rate of 5 ℃ / min and then cooled with the furnace to obtain the pre-synthesized powder.

[0055] Step 4, Granulation and tableting: PVA aqueous solution was added to the obtained pre-synthesized powder, mixed evenly, and then sieved to obtain particles of 50 to 100 mesh. The concentration of the PVA aqueous solution (type 1750) was 8 wt%, and the mass ratio of the amount added to the pre-synthesized powder was 1:5.

[0056] The sieved particles are placed in a tablet press and pressed at 4 MPa to obtain a ceramic green body.

[0057] Step 5, glue removal: The ceramic green body obtained in step 4 is placed in an alumina crucible and then placed in a box furnace. It is heated to 650 °C at a heating rate of 1 °C / min to remove the binder. The green body is then cooled to room temperature in the furnace to obtain the ceramic green body after binder removal.

[0058] Step 6, Sintering: The obtained ceramic green body is placed in an alumina crucible and then placed in a box furnace. The ceramic green body is then sintered.

[0059] During sintering, the furnace is heated to 1250 ℃ at a rate of 5 ℃ / min and held for 4 h. After the holding period, the furnace is cooled to 500 ℃ at a rate of 5 ℃ / min and then cooled to room temperature.

[0060] The sintered ceramic green body was removed, ground and polished to obtain a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability.

[0061] Example 4 This embodiment describes a perovskite-structured high-entropy ceramic material (Ca) with excellent dielectric temperature stability. 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.80 Zr 0.20 The specific process of O3 is as follows: Step 1, Ingredients: According to (Ca) 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.80 Zr 0.20 The initial raw materials CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2, and TiO2 are accurately weighed according to the stoichiometric ratio of the chemical formula O3; the amounts of CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2, and TiO2 are based on (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti) 0.80 Zr 0.20 O3 was calculated.

[0062] Step 2, prepare the mixed powder: The initial raw materials weighed in step 1, ZrO2 grinding beads, and anhydrous ethanol were added to a polytetrafluoroethylene grinding jar and ball-milled for 12 h. The weight ratio of anhydrous ethanol to initial raw materials was 1:1, and the weight ratio of grinding beads to initial raw materials was 2:1. The ball-milled slurry was placed in an oven for drying at 60 ℃ for 3 h. The mixture was then ground to obtain a mixed powder.

[0063] Step 3, Preparation of pre-synthesized powder: The mixed powder obtained in step 2 was placed in a sealed crucible and heated to 1275 ℃ in a high-temperature muffle furnace at a heating rate of 5 ℃ / min. After holding at this temperature for 2 h, the temperature was reduced to 500 ℃ at a cooling rate of 5 ℃ / min and then cooled with the furnace to obtain the pre-synthesized powder.

[0064] Step 4, Granulation and tableting: PVA aqueous solution was added to the obtained pre-synthesized powder, mixed evenly, and then sieved to obtain particles of 50 to 100 mesh. The concentration of the PVA aqueous solution (type 1750) was 8 wt%, and the mass ratio of the amount added to the pre-synthesized powder was 1:5.

[0065] The sieved particles are placed in a tablet press and pressed at 5 MPa to obtain a ceramic green body.

[0066] Step 5, glue removal: The ceramic green body obtained in step 4 is placed in an alumina crucible and then placed in a box furnace. It is heated to 650 °C at a heating rate of 1 °C / min to remove the binder. The green body is then cooled to room temperature in the furnace to obtain the ceramic green body after binder removal.

[0067] Step 6, Sintering: The obtained ceramic green body is placed in an alumina crucible and then placed in a box furnace. The ceramic green body is then sintered.

[0068] During sintering, the furnace is heated to 1275 ℃ at a rate of 5 ℃ / min and held for 2 h. After the holding period, the furnace is cooled to 500 ℃ at a rate of 5 ℃ / min and then cooled to room temperature.

[0069] The sintered ceramic green body was removed, ground and polished to obtain a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability.

[0070] Experimental Example 1) Determination of the phase structure of high-entropy dielectric ceramics High-entropy oxide phase analysis was performed using X-ray diffraction (XRD) with an X'Pert PRO diffractometer from the Dutch analytical instrument company. The scanning angle range was 2θ = 10–90°, the scanning speed was 5 ° / min, and the step size was 0.01°. The obtained powder diffraction results are shown below. Figure 2 . Figure 2 Examples 1 to 3 demonstrate that the phase composition of a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability is a single-phase perovskite structure.

[0071] 2) Microstructure and elemental distribution of high-entropy dielectric ceramics The microstructure of the cross-section of the high-entropy dielectric ceramic sample was observed using a focused ion / electron dual-beam electron microscope (FIB: Helios G4 CX) from FEI (USA). The distribution of various elements potentially present in the observed region was tested using an energy dispersive spectrometer (EDS: Thermo NS7) from Thermo Fisher Scientific. Figures 3-6 As shown. From Figures 3-6 It can be seen that the high-entropy dielectric ceramic described in this application has complete grains and uniform distribution of elements Ca, Sr, Ba, Mg, Bi, Na, Ti, and Zr.

[0072] Appendix 3-6 shows scanning electron microscope images of the ceramic material. The ceramic has well-grown grains and a dense structure. There are few pores in the microstructure of the sample. At the same time, the elements Ca, Sr, Ba, Mg, Bi, Na, Ti and Zr are uniformly distributed inside the ceramic without agglomeration.

[0073] 3) Dielectric temperature spectrum of high-entropy dielectric ceramic materials The capacitance (C) and dielectric loss (tanδ) of the samples were measured using an Agilent Technologies E4980A digital bridge and a Bailibo Technology DMS-2000 high and low temperature dielectric temperature spectroscopy system at a heating rate of 3 °C / min. The capacitive-temperature change rate of the high-entropy dielectric ceramic material is shown in Table 2.

[0074] Table 2. Temperature Change Rate of High-Entropy Ceramic Materials

[0075] Figure 7 The curves showing the change of dielectric constant and dielectric loss of the ceramic material obtained by the process of this application with temperature are presented. It can be seen that the high entropy and doping design ideas adopted in this application effectively improve the dielectric constant.

[0076] Figure 8 The temperature change rate |Δε| / ε of the ceramic material obtained by the process of this application is shown. 25 ≤10% (-45 ℃~90 ℃), wherein the capacitance temperature change rate of Examples 1, 3, and 4 meets the X7R capacitor standard, and Example 2 meets the X6R standard. That is, while having a high dielectric constant and low dielectric loss, it has excellent dielectric temperature stability.

[0077] Although the embodiments of this application have been described above in conjunction with the accompanying drawings, this application is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of this application, and these are all within the scope of protection of this application.

Claims

1. A perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability, characterized in that, The chemical formula of the high-entropy ceramic material is (Ca... 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zr x O3, where x = 0.05~0.

2.

2. The perovskite-structured high-entropy ceramic material according to claim 1, characterized in that, The value of x is 0.05, 0.1, 0.15 or 0.

2.

3. The perovskite-structured high-entropy ceramic material according to claim 1, characterized in that, The raw materials for synthesizing the high-entropy ceramic material are CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2 and TiO2. The purity of each raw material is analytical grade and the particle size is in the micrometer range.

4. A method for preparing a perovskite-structured high-entropy ceramic material with excellent dielectric temperature stability, characterized in that, Includes the following steps: Step 1, according to (Ca 0.2 Sr 0.2 Ba 0.2 Mg 0.2 Bi 0.1 Na 0.1 (Ti1) x Zr x The stoichiometric ratio of the raw materials CaCO3, SrCO3, BaCO3, MgO, Na2CO3, Bi2O3, ZrO2 and TiO2 was weighed out. Step 2: Mix the weighed raw materials with ball milling beads and anhydrous ethanol, then ball mill, dry and grind to obtain a mixed powder; Step 3: Place the mixed powder in a crucible and pre-synthesize it at 1225℃~1275℃ for 2~4 hours. After cooling, the pre-synthesized powder is obtained. Step 4: Add binder to the pre-synthesized powder, mix and sieve, take 50-100 mesh particles and press them into ceramic blanks; Step 5: Heat the ceramic green body to 650°C to remove the binder, and obtain a ceramic green body; Step 6: Sinter the ceramic green body at 1225℃~1275℃, hold for 2~4h, and then cool to obtain the perovskite structure high-entropy ceramic material with excellent dielectric temperature stability.

5. The method for preparing perovskite-structured high-entropy ceramic materials according to claim 4, characterized in that, In step 2, the ball milling time is 8–12 hours, the drying temperature is 50℃–60℃, and the drying time is 3–12 hours.

6. The method for preparing perovskite-structured high-entropy ceramic materials according to claim 4, characterized in that, In steps 3 and 6, the temperature is increased to 1225℃~1275℃ at a heating rate of 5℃ / min, and after holding at that temperature, the temperature is reduced to 500℃ at a cooling rate of 2℃ / min~5℃ / min, and then cooled with the furnace.

7. The method for preparing perovskite-structured high-entropy ceramic materials according to claim 4, characterized in that, In step 4, the pressing pressure of the ceramic blank is 2MPa to 5MPa.

8. The method for preparing perovskite-structured high-entropy ceramic materials according to claim 4, characterized in that... In step 5, the temperature is increased to 650°C at a rate of 0.5°C / min to 1°C / min for debinding.

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