Glass ceramic material with high hardness and high dielectric energy storage performance and preparation method thereof

Abstract

The invention particularly relates to a microcrystalline glass material with high hardness and high dielectric energy storage performance, which is suitable for high-power pulse energy storage devices, high-frequency electronic equipment and insulation protection systems in extreme environments. The prepared microcrystalline glass dielectric material is characterized in that a main crystal phase separated from parent phase glass and a high-hardness crystal phase are subjected to composite heterogeneous growth to form a continuous interface structure. The chemical components of the main crystal phase and the high-hardness crystal phase are respectively BaTiO3 and MlSi12-(m + n) Alm + nOnN16-n (wherein M is a metal cation with a stable structure, and l, m and n are the number of corresponding atoms in the crystal structure). The maximum Vickers hardness of the obtained microcrystalline glass material can reach 1045 Hv and is approximately equal to 10.24 GPa, the maximum actual measurement discharge energy storage density can reach 14.43 J / cm < 3 > at 2400 kV / cm, and the maximum peak power density can reach about 1900 MW / cm < 3 >. Meanwhile, the glass composition is free of lead, the purpose of environmental protection is achieved, and the glass is suitable for batch production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electronic functional materials, and particularly relates to a microcrystalline glass material with high hardness and high dielectric energy storage performance, which is suitable for high-power pulse energy storage devices, high-frequency electronic devices and insulation protection systems in extreme environments. BACKGROUND

[0002] Dielectric capacitors are widely used in high-voltage pulse power electronic systems due to their ultrafast charging / discharging speed, low cost, simple preparation, and good thermal stability. With the rapid development of modern electronic power technology towards lightweight, miniaturization, and high reliability, more stringent requirements are placed on dielectric energy storage materials. Ideal dielectric materials should have high dielectric constant, high breakdown field strength, low dielectric loss, and excellent mechanical properties to meet the demands of high energy density storage and long-term stable operation.

[0003] Currently, common dielectric materials mainly include ceramics, polymers, and glasses (including microcrystalline glass), but all have inherent limitations: ceramic materials (such as barium titanate, niobate-based, and sodium bismuth titanate-based ceramics) have high dielectric constant, but their breakdown field strength is usually low (generally less than 500 kV / cm), they are brittle and have limited hardness, and they are prone to cracking under mechanical stress or thermal shock, which restricts their application in flexible devices or high-reliability systems; polymer materials (such as polypropylene and polyimide) have high breakdown field strength and good flexibility, but their dielectric constant is generally low (usually less than 10), and they have poor temperature resistance (usually below 200°C), which makes them prone to aging and decomposition in high-power or high-temperature environments, leading to rapid decay of energy storage density; ordinary glass materials (such as silicate and phosphate glasses) have good insulation performance, but their dielectric constant is low (usually in the range of 10-20), their energy storage density is limited, and their hardness and toughness are difficult to balance, which cannot meet the demand of high-load working conditions; microcrystalline glass forms nanometer / micrometer-sized crystal phases in the glass matrix through controlled crystallization, combining the advantages of glass forming and the functional properties of ceramics, and has good structural high-temperature stability, making it an ideal system to break through the above bottlenecks. However, in existing microcrystalline glass materials, the dielectric properties of the crystal phase and the glass phase are poorly matched, and charge accumulation and local electric field distortion easily occur at the interface, resulting in a significant reduction in breakdown field strength. At the same time, high hardness and high energy storage density are usually mutually restrictive: increasing the crystal content can enhance dielectric response, but it will sacrifice the material's density and mechanical strength; excessive pursuit of hardness may inhibit the optimization of dielectric properties.

[0004] Therefore, it is a technical problem to be solved in the field to develop a microcrystalline glass material that achieves synergistic improvement of high hardness and high dielectric energy storage performance through microstructure design. SUMMARY

[0005] To solve the above problems, the application successfully prepares a microcrystalline glass material with a continuous growth interface structure and a multi-phase heterogeneous composite through component design and specific crystallization process, which has high hardness and high dielectric energy storage performance. The application provides a microcrystalline glass material with high hardness and high dielectric energy storage performance, which comprises a main crystal phase, a high-hardness crystal phase and a parent phase glass phase, the main crystal phase and the high-mechanical-strength crystal phase are obtained by crystallization from the parent phase glass phase, and a multi-phase heterogeneous composite nanocrystal with a continuous growth interface structure is obtained in the glass phase; the main crystal phase is a cubic barium titanate crystal material with a perovskite structure, and the high-hardness crystal phase is an α-SiAlON phase crystal material. The microcrystalline glass material has high mechanical hardness and excellent dielectric energy storage performance, and greatly improves the breakdown field strength, energy storage density, power density and Vickers hardness of the microcrystalline glass.

[0006] As a preferred technical solution, the chemical composition of the parent phase glass phase is BaO-M x O y -SiO2-Al2O3-TiO2-Si3N4 (wherein M is a metal cation stabilizing the structure, including one or more of alkaline earth metal ions Mg 2+ , Ca 2+ , post-transition metal ions Sn 2+ , Bi 3+ , Ga 3+ , In 3+ , and metalloid ions Ge 4+ , Sb 3+ , and x and y are the atomic proportions of the corresponding metal cation oxides), the chemical formula of the main crystal phase is BaTiO3, and the chemical formula of the high-hardness crystal phase is M l Si 12-(m+n) Al m+n O n N 16-n (wherein l, m and n are the atomic numbers of the corresponding atoms in the crystal structure).

[0007] As a preferred technical solution, the chemical composition of the microcrystalline glass material is aBaTiO3-bM l Si 12-(m+n) Al m+n O n N 16-n ; wherein a and b are the mole percentages of the main crystal phase and the high-hardness crystal phase, respectively, 85≤a≤90%, and 10%≤b≤15%.

[0008] The application also provides a preparation method of the above microcrystalline glass material, comprising the following steps:

[0009] S1, preparing a parent phase glass phase according to aBaO-bMx O y -SiO2-Al2O3-TiO2-Si3N4, ball milling the ingredients for 24h, drying and placing in a crucible at a melting temperature of 1400-1600℃ for 0.5-2h, melting into a uniform glass liquid;

[0010] S2, rapidly pouring the glass liquid of step S1 into a metal mold for shaping, then cutting into rectangular glass pieces with an area of 1-2cm 2 after annealing at 550-650℃ for 4-10h to eliminate stress;

[0011] S3, heating the glass pieces prepared in step S2 at a heating rate of 3℃ / min, nucleating at 690-730℃ for 1-4h, main crystal phase crystallization at 800-900℃ for 1-4h, and high-hardness crystal phase crystallization at 900-1000℃ for 1-4h, to obtain a glass-ceramic dielectric material.

[0012] As a preferred technical solution, the annealing temperature in step S2 is 600℃, and the annealing time is 4h.

[0013] As a preferred technical solution, in step S3, the nucleation temperature is 660℃, the nucleation time is 1.5h; the main crystal phase crystallization temperature is 825℃, the crystallization time is 1.5h; and the high-hardness crystal phase crystallization temperature is 925℃, the crystallization time is 1.5h.

[0014] The application further provides a preparation method of a glass-ceramic material capable of dielectric energy storage performance testing, comprising the following steps:

[0015] S1, according to aBaO-bM x O y -SiO2-Al2O3-TiO2-Si3N4, ball milling the ingredients for 24h, drying and placing in a crucible at a melting temperature of 1400-1600℃ for 0.5-2h, melting into a uniform glass liquid;

[0016] S2, rapidly pouring the glass liquid of step S1 into a metal mold for shaping, then cutting into rectangular glass pieces with an area of 1-2cm 2 after annealing at 550-650℃ for 4-10h to eliminate stress;

[0017] S3, heating the glass pieces prepared in step S2 at a heating rate of 3℃ / min, nucleating at 690-730℃ for 1-4h, main crystal phase crystallization at 800-900℃ for 1-4h, and high-hardness crystal phase crystallization at 900-1000℃ for 1-4h, to obtain a glass-ceramic dielectric material.

[0018] S4, the microcrystalline glass medium material obtained in step S3 is polished into a sheet with a thickness of 0.05mm-1mm for Vickers hardness testing; in addition, the material for electrical testing needs to be coated with a medium temperature silver paste by silk screen printing or manual coating, and then sintered and solidified at 600℃ to form a metal silver electrode.

[0019] The microcrystalline glass material provided by the application has high hardness and excellent energy storage performance, and has the following beneficial effects:

[0020] By adjusting the glass base composition, using the nano-crystallization engineering regulation method of multi-step nucleation and crystallization, a multi-phase heterogeneous composite microcrystalline glass material with a continuous growth interface structure is obtained, and a microcrystalline glass material with high Vickers hardness, high energy storage density, high power density and ultra-high breakdown field strength is obtained. The Vickers hardness of the obtained microcrystalline glass material is up to 1045Hv≈10.24GPa, the measured discharge energy storage density is up to 14.43 J / cm 3 @2400 kV / cm, and the peak power density is up to about 1900MW / cm 3 . At the same time, the glass composition is lead-free, which achieves the purpose of environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1(a) is a high-resolution TEM photo of the multi-phase heterogeneous composite interface of the continuous growth interface structure of the microcrystalline glass sample prepared in Example 1; 1(b) is a Vickers hardness test result graph of the prepared microcrystalline glass sample; 1(c) is a measured discharge energy density curve and highest power density of the prepared microcrystalline glass sample.

[0022] Figure 2(a) is a Vickers hardness test result graph of the microcrystalline glass sample prepared in Example 2; 2(b) is a measured discharge energy density curve and highest power density of the prepared microcrystalline glass sample.

[0023] Figure 3(a) is a Vickers hardness test result graph of the microcrystalline glass sample prepared in Example 3; 3(b) is a measured discharge energy density curve and highest power density of the prepared microcrystalline glass sample. DETAILED DESCRIPTION

[0024] The technical solutions of the application will be described in detail below in combination with the drawings and specific examples, but the protection scope of the application is not limited to the examples.

[0025] Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the application belongs. If the definition of a specific term disclosed in the prior art is inconsistent with any definition provided in the application, the definition of the term provided in the application shall prevail.

[0026] As used herein, and unless the context clearly indicates otherwise, no limitation on the singular or plural number of a characteristic is intended. It is also to be understood that the term "made" as used herein is synonymous with "comprising," "including," "carrying," "having," "containing," and / or "comprising," as these terms are used in the specification, mean the stated composition, step, method, article, or apparatus, but do not exclude the presence of one or more additional compositions, steps, methods, articles, or apparatus. Furthermore, use of "preferred" or "preferably" or "more preferred" or "more preferably" or "most preferred" or "most preferably" in describing embodiments of the application indicates that in certain situations, the disclosed embodiment can provide certain benefits, however, other embodiments can also be preferred, in the same or other situations. In addition, recitation of one or more preferred embodiments does not signify that other embodiments are not useful, and are not intended to exclude other embodiments from the scope of the application.

[0027] To solve the above problems, the present application successfully prepares a microcrystalline glass material with a continuous growth interface structure and a multi-phase heterogeneous composite by component design and a specific crystallization process, which has high hardness and high dielectric energy storage performance. The present application provides a microcrystalline glass material with high hardness and high dielectric energy storage performance, which comprises a main crystal phase, a high-hardness crystal phase and a parent phase glass phase, the main crystal phase and the high-mechanical-strength crystal phase are obtained by crystallization from the parent phase glass phase, and a multi-phase heterogeneous composite nanocrystal with a continuous growth interface structure is obtained in the glass phase; the main crystal phase is a cubic barium titanate crystal material with a perovskite structure, and the high-hardness crystal phase is an α-SiAlON phase crystal material. The microcrystalline glass material has high mechanical hardness and excellent dielectric energy storage performance, and greatly improves the breakdown field strength, energy storage density, power density and Vickers hardness of the microcrystalline glass.

[0028] Embodiment

[0029] Example 1 :

[0030] Embodiment 1 provides a microcrystalline glass material with high hardness and high dielectric energy storage performance, and the parent phase glass composition of the material is BaO-M x O y -SiO2-Al2O3-TiO2-Si3N4, and the metal cation selected from M=Ca 2+ , and the chemical main components are aBaO-bCaO-SiO2-Al2O3-TiO2-Si3N4, wherein a=90%, b=10%.

[0031] Embodiment 1 also provides a preparation method of the microcrystalline glass material, comprising the following steps:

[0032] S1, using BaCO3, CaCO3, TiO2, SiO2, Al2O3, Si3N4 with analytical purity (purity≥99%) as starting materials, and then the materials are ball milled in a ball mill for 24 h, dried and placed in a crucible to be melted into a uniform glass liquid at 1500°C for 1.5 h;

[0033] S2, the glass liquid of S1 is rapidly poured into a metal mold to form a glass sheet, and then annealed at 600°C for 4 h to eliminate stress, and then cut into a rectangular glass sheet with an area of 1 cm 2 ;

[0034] S3, the glass sheet is heated at a heating rate of 3°C / min, nucleated at 690°C for 2 h, and then further heated at a heating rate of 3°C / min, main crystal phase crystallization at 875°C for 1.5 h, and high-hardness phase crystallization at 950°C for 1.5 h to obtain a glass-ceramic material.

[0035] In order to test the Vickers hardness and electrical properties of the glass-ceramic material obtained above, the following steps are required:

[0036] S4, the glass-ceramic material obtained in step S3 is polished to a thickness of 1 mm, and then Vickers hardness test is performed; if electrical test is required, the sheet is further coated with a middle-temperature silver paste (Guiyan Platinium Industry) by screen printing or hand coating, and then sintered and solidified at 600°C to form a metal silver electrode.

[0037] Test results show that the high-resolution TEM photo of the multi-phase heterogeneous composite interface of the continuous growth interface structure of the glass-ceramic material sample is shown in FIG. 1(a), and it can be seen that the crystal phase structure of the material is a multi-phase composite structure of BaTiO3 phase and SiAlON phase, and the interface has a continuous growth structure. The Vickers hardness test results are shown in FIG. 1(b), and the Vickers hardness calculated according to the plastic deformation size under the action of a load of 9.8 N for 15 s is up to 1045 HV, about 10.24 GPa. The actual measured discharge energy storage density is up to 14.43 J / cm 3 @2400 kV / cm (as shown in FIG. 1(c)), and the peak power density is up to about 1900 MW / cm 3 . Test conditions: Vickers hardness test (China Laizhou Huayin Test Instrument Co., Ltd., 200HV-5 Vickers hardness tester, room temperature test), charge and discharge test system (voltage 10 kV, load 200 Ω, test temperature 25°C, domestic charge and discharge test system, test principle is to test the discharge current change with time after the dielectric material is charged and calculate the energy storage density and power density by using RLC oscillation circuit).

[0038] Example 2 :

[0039] Example 2 provides a microcrystalline glass material with high hardness and high dielectric energy storage performance, the parent phase glass composition of the material is BaO-M x O y -SiO2-Al2O3-TiO2-Si3N4, and the metal cation selected in M=Sn 2+ , and the chemical main components are aBaO-bSnO-SiO2-Al2O3-TiO2-Si3N4, wherein a=87.5%, b=12.5%.

[0040] Example 1 also provides a preparation method of the microcrystalline glass material, comprising the following steps:

[0041] S1, using analytical pure (purity≥99%) BaCO3, SnO, TiO2, SiO2, Al2O3, Si3N4 as starting raw materials, according to the molar ratio of 87.5% BaCO3-12.5% SnO-SiO2-Al2O3-TiO2-Si3N4, then wet ball milling these raw materials in a ball mill for 24h, and then drying and placing in a crucible to melt into a uniform glass liquid at 1450℃ for 1.5h;

[0042] S2, pouring the glass liquid of S1 into a metal mold for shaping, then annealing in an annealing furnace at 600℃ for 4h to eliminate stress, and then cutting into a rectangular glass sheet with an area of 1cm 2 ;

[0043] S3, heating the glass sheet at a heating rate of 3℃ / min, nucleating at 690℃ for 2h, then continuing to heat at a heating rate of 3℃ / min, main crystal phase crystallization at 875℃ for 1.5h, and high-hardness phase crystallization at 950℃ for 1.5h, to obtain a microcrystalline glass material.

[0044] In order to test the Vickers hardness and electricity of the microcrystalline glass material obtained above, the following steps are also needed:

[0045] S4, polishing the microcrystalline glass dielectric material obtained in step S3 into a thin sheet with a thickness of 1mm, and then performing Vickers hardness test; if electrical test is needed, the thin sheet also needs to be coated with a middle-temperature silver paste (Guiyan Platinum Industry) by silk screen printing or manual coating, and then sintered and solidified at 600℃ to form a metal silver electrode.

[0046] The Vickers hardness test result is shown in Fig. 2(a). The Vickers hardness of the material is calculated to be 1041 HV, about 10.20 GPa, according to the plastic deformation size under the load of 1.962 N for 15 s. The measured discharge energy density of the material is 10.62 J / cm 3 @1600 kV / cm (as shown in Fig. 2(b)), the peak power density can reach about 1600 MW / cm 3 . Test conditions: Vickers hardness test (China Laizhou Huayin Test Instrument Co., Ltd., 200HV-5 Vickers hardness tester, room temperature test), charge and discharge test system (voltage 10 kV, load 200 Ω, test temperature 25°C, domestic charge and discharge test system, the test principle is to test the discharge current change with time after the dielectric material is charged and calculate the energy density and power density by using RLC oscillation circuit).

[0047] Example 3 :

[0048] Example 3 provides a microcrystalline glass material with high hardness and high dielectric energy storage performance. The parent phase glass composition of the material is BaO-M x O y -SiO2-Al2O3-TiO2-Si3N4, and the metal cation selected in the composition is M=Ge 4+ . The chemical main component of the material is aBaO-bGeO2-SiO2-Al2O3-TiO2-Si3N4, where a=85%, b=15%.

[0049] Example 1 also provides a preparation method of the microcrystalline glass material, which comprises the following steps:

[0050] S1, using analytical pure (purity≥99%) BaCO3, GeO2, TiO2, SiO2, Al2O3, and Si3N4 as starting raw materials, the raw materials are prepared according to the molar ratio of 85% BaCO3-15% GeO2-SiO2-Al2O3-TiO2-Si3N4, then the raw materials are wet ball milled in a ball mill for 24 h, dried and placed in a crucible to be melted into a uniform glass liquid at 1550°C for 1.5 h;

[0051] S2, the glass liquid of S1 is quickly poured into a metal mold to form, then annealed in an annealing furnace at 600°C for 4 h to eliminate stress, and then cut into a rectangular glass sheet with an area of 1 cm 2 ;

[0052] S3, the glass sheet is heated at a heating rate of 3 ℃ / min, nucleated at 690 ℃ for 2 h, then continues to heat at a heating rate of 3 ℃ / min, main crystal phase crystallization at 875 ℃ for 1.5 h, high hardness phase crystallization at 950 ℃ for 1.5 h, to obtain the glass-ceramic material.

[0053] In order to test the Vickers hardness and electrical properties of the glass-ceramic material obtained above, the following steps are needed:

[0054] S4, the glass-ceramic material obtained in step S3 is polished to a thickness of 1 mm, and then Vickers hardness test is performed; if electrical test is needed, the sheet is coated with silver paste (Guiyan Platinium Industry) by silk screen printing or hand coating, and then sintered at 600 ℃ to form silver electrode.

[0055] Test results of Vickers hardness test are shown in FIG. 3(a), and the Vickers hardness of the glass-ceramic material is calculated to be 926 HV, about 9.07 GPa, according to the plastic deformation size under the load of 9.8 N for 15 s. The measured discharge energy density is about 8.71 J / cm 3 @1800 kV / cm (as shown in FIG. 3(b)), and the peak power density is about 700 MW / cm 3 . Test conditions: Vickers hardness test (China Laizhou Huayin Test Instrument Co., Ltd., 200HV-5 Vickers hardness tester, room temperature test), charge-discharge test system (voltage 10 kV, load 200 Ω, test temperature 25℃, domestic charge-discharge test system, test principle is to test the discharge current of the dielectric material with RLC oscillation circuit after charging, and calculate the energy density and power density).

Claims

1. A microcrystalline glass material with high hardness and high dielectric energy storage performance, characterized in that: The material comprises a glass phase, a main crystal phase and a high-hardness crystal phase, the main crystal phase and the high-hardness crystal phase are obtained by being separated from the glass phase, and a nanocrystal with a continuous interface structure formed by the composite heterogeneous growth of the main crystal phase and the high-hardness crystal phase is obtained in the glass phase; the main crystal phase is a cubic phase BaTiO3 with a perovskite structure, and the high-hardness crystal phase has a chemical general formula of M l Si 12-(m+n) Al m+n O n N 16-n .

2. The microcrystalline glass material as described in claim 1, characterized in that: The chemical formula of the glass phase is BaO-M x O y -SiO2-Al2O3-TiO2-Si3N4, wherein M is a metal cation stabilizing the structure, including alkaline earth metal ions Mg 2+ ,Ca 2+ , post-transition metal ions Sn 2+ , Bi 3+ , Ga 3+ , In 3+ , and metalloid ions Ge 4+ , Sb 3+ , one or several of them, x, y are the atomic proportions of the metal cation oxides, the chemical formula of the main crystalline phase is BaTiO3, and the high-hardness crystalline phase has a general chemical formula of M l Si 12-(m+n) Al m+n O n N 16-n .

3. The microcrystalline glass material as described in claim 2, characterized in that: The chemical composition of the microcrystalline glass material is: aBaTiO3-bM l Si 12-(m+n) Al m+n O n N 16-n Wherein, a and b are the molar percentages of the main crystalline phase and the high-hardness crystalline phase, respectively, with 85 ≤ a ≤ 90% and 10% ≤ b ≤ 15%.

4. A method for preparing a microcrystalline glass material as described in any one of claims 1-3, characterized in that, The method includes the following steps: S1, according to aBaO-bM x O y The ingredients are prepared in the following proportions: SiO2-Al2O3-TiO2-Si3N4. The ingredients are ball-milled for 24 hours, dried, and then placed in a crucible and kept at a melting temperature of 1400℃-1600℃ for 0.5h-2h to melt them into a uniform glass melt. S2. The molten glass is rapidly poured into a metal mold to form the shape, and then annealed in an annealing furnace at 550-650℃ for 4-10 hours to relieve stress. After annealing, it is cut into pieces with an area of ​​1 cm². 2 ~2cm 2 A rectangular glass plate; S3. The glass sheet is heated at a heating rate of 3℃ / min, held at 690-730℃ for 1-4h for nucleation, held at 800-900℃ for 1-4h for crystallization of the main crystalline phase, and then held at 900-1000℃ for 1-4h for crystallization of the high-hardness crystalline phase to obtain a microcrystalline glass medium material.

5. The method for preparing the microcrystalline glass material as described in claim 4, characterized in that: The annealing temperature in step S2 is 600℃, and the annealing time is 4 hours.

6. The method for preparing the microcrystalline glass material as described in claim 4, characterized in that: In step S3, the nucleation temperature is 690℃ and the nucleation time is 2h; the crystallization temperature of the main crystalline phase is 875℃ and the crystallization time is 1.5h; the crystallization temperature of the high-hardness crystalline phase is 950℃ and the crystallization time is 1.5h.

7. A method for preparing a microcrystalline glass material capable of Vickers hardness and electrical testing, characterized in that, Includes the following steps: S1, according to aBaO-bM x O y The ingredients are prepared in the following proportions: SiO2-Al2O3-TiO2-Si3N4. The ingredients are ball-milled for 24 hours, dried, and then placed in a crucible and kept at a melting temperature of 1400℃-1600℃ for 0.5h-2h to melt them into a uniform glass melt. S2. Quickly pour the molten glass from step S1 into a metal mold to form the shape, then anneal it in an annealing furnace at 550℃-650℃ for 4-10 hours to relieve stress, and finally cut it into pieces with an area of ​​1 cm². 2 ~2cm 2 A rectangular glass plate; S3. The glass slide prepared in step S2 is heated at a heating rate of 3℃ / min, nucleated at 690-730℃ for 1-4h, crystallized at 800-900℃ for 1-4h, and then crystallized at 900-1000℃ for 1-4h to obtain the microcrystalline glass medium material. S4. Polish the microcrystalline glass dielectric material obtained in step S3 into a thin sheet with a thickness of 0.05mm-1mm and perform Vickers hardness testing; for electrical testing, the microcrystalline glass dielectric material also needs to be screen-printed or manually coated with medium-temperature silver paste, and then sintered and solidified at 600℃ to form a metallic silver electrode.

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