Modified barium titanate high-temperature ceramic material as well as solid-phase sintering preparation method and application thereof
Through the solid phase sintering method optimized by specific auxiliary materials and processes, the dielectric performance and stability of barium titanate ceramics in high temperature environments are solved, and efficient and environmentally friendly industrial production is achieved.
Patent Information
- Application Number
- CN202510454611.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2025-07-15
AI Technical Summary
The prior art is difficult to maintain the dielectric performance stability of barium titanate ceramics under high temperature environments. At the same time, liquid phase synthesis methods have high costs and environmental pollution problems, and lack solid phase sintering processes suitable for industrialization.
A specific proportion of strontium carbonate, sodium carbonate and niobium pentoxide are used as auxiliary materials, mixed with barium titanate powder, and modified barium titanate high-temperature ceramic materials are prepared through solid-phase sintering process, including pre-firing, crushing, grinding and carbon discharge treatment, and the particle size distribution is optimized.
It improves the dielectric performance and high temperature resistance of barium titanate ceramics in high temperature environments, and realizes industrial scale production, reducing costs and environmental impact.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of ceramic capacitors, relates to a high-temperature ceramic material, and particularly relates to a modified barium titanate high-temperature ceramic material, a solid-phase sintering preparation method thereof, and an application thereof. Background Art
[0002] In recent years, with the continuous improvement of market requirements, the working environment of electronic devices has become more and more demanding. For example, the working temperature range in fields such as aerospace and oil drilling has been higher than 150 °C. Due to the polarization characteristics of barium titanate ceramics, when it works at a temperature higher than the Curie point (about 110 °C), it transforms into a paraelectric phase and loses its polarization characteristics. In order to ensure that the barium titanate high-temperature ceramic capacitor can work stably within the working temperature range above 150 °C, it is necessary to modify and adjust it so that it has high dielectric constant, low dielectric loss, and good temperature stability in the high-temperature range; in addition, currently, the dielectric materials of high-temperature ceramic capacitors all contain harmful elements such as lead and cadmium, which will cause serious harm to human health and the ecological environment.
[0003] Most of the existing technologies use the liquid-phase synthesis method for the industrial production of modified barium titanate ceramic materials. However, the liquid-phase synthesis method has high raw material costs, complex processing technologies, and requires high pressure and temperature, resulting in high investment and construction scale costs; at the same time, a large amount of waste water needs to be discharged during the hydrothermal synthesis process, causing serious environmental pollution. Compared with liquid-phase synthesis, solid-phase sintering has high sintering efficiency, rich raw material sources, small one-time investment, simple process, high degree of process automation, and low labor intensity, and is more likely to achieve industrialized and large-scale production, but there is no industrial method for producing modified barium titanate high-temperature ceramic materials.
[0004] Therefore, how to improve the solid-phase sintering process, use the solid-phase sintering process for the large-scale industrial production of barium titanate high-temperature ceramic materials, and optimize the composition of barium titanate high-temperature ceramic materials is a technical problem that needs to be solved urgently at present. Summary of the Invention
[0005] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a modified barium titanate high-temperature ceramic material, a solid-phase sintering preparation method thereof, and an application thereof. The solid-phase sintering preparation method can enable the modified barium titanate high-temperature ceramic material to have good dielectric properties in a high-temperature environment; at the same time, it is also conducive to realizing industrialized scale production.
[0006] To achieve the purpose of this invention, the present invention adopts the following technical solutions:
[0007] In the first aspect, the present invention provides a solid-phase sintering preparation method of a modified barium titanate high-temperature ceramic material, and the solid-phase sintering preparation method includes:
[0008] Mix the barium titanate powder with the auxiliary material powder, and sinter the obtained mixed powder to obtain the modified barium titanate high-temperature ceramic material;
[0009] The preparation raw materials of the auxiliary material powder include strontium carbonate, sodium carbonate and niobium pentoxide with a molar ratio of (7-9):1:(2-4);
[0010] The molar ratio of the barium titanate powder to the auxiliary material powder is 80:1 - 90:1.
[0011] The solid-phase sintering preparation method provided by the present invention can improve the dielectric properties of barium titanate ceramics in a high-temperature environment only by simply using auxiliary materials; moreover, the solid-phase sintering preparation method provided by the present invention is simple and feasible, and can realize the industrial-scale production of modified barium titanate high-temperature ceramic materials.
[0012] Preferably, the heating rate of the sintering treatment is 2°C / min - 10°C / min.
[0013] Preferably, the highest temperature of the sintering treatment is 1200°C - 1480°C.
[0014] Preferably, the holding time at the highest temperature of the sintering treatment is 0.5h - 3h.
[0015] Preferably, the auxiliary material powder is prepared by the following solid-phase sintering preparation method: Mix strontium carbonate, sodium carbonate and niobium pentoxide according to the formula amount, dry and degasify the mixed powder, and then perform auxiliary material crushing treatment to obtain the auxiliary material powder.
[0016] Preferably, the temperature of the drying is 80°C - 180°C, and the time is 6h - 18h.
[0017] Preferably, the temperature of the degasification is 450°C - 800°C, and the time is 8h - 18h.
[0018] Preferably, the barium titanate powder is prepared by the following solid-phase sintering preparation method: Mix the barium source and the titanium source to obtain the raw material powder; then perform pre-sintering treatment on the raw material powder to obtain the pre-sintered blank; the pre-sintered blank is successively subjected to first crushing treatment, grinding, degasification treatment and second crushing treatment to obtain the barium titanate powder.
[0019] Preferably, the median particle sizes of the barium source and the titanium source are independently 3μm - 15μm.
[0020] Preferably, the molar ratio of Ba in the barium source to Ti in the titanium source is 0.990:1 - 1.010:1.
[0021] Preferably, the median particle size D50 of the raw material powder is 0.8μm - 3.5μm.
[0022] Preferably, the heating rate of the pre-sintering is 5 °C / min - 10 °C / min.
[0023] Preferably, the maximum temperature of the pre-sintering is 1150 °C - 1350 °C.
[0024] Preferably, the heat preservation time at the maximum temperature of the pre-sintering is 30 min - 180 min.
[0025] Preferably, the method of the first crushing treatment includes depolymerization.
[0026] Preferably, the median particle size D50 of the powder after the first crushing treatment is 0.8 μm - 3.5 μm.
[0027] Preferably, the method of the grinding includes sand grinding; the median particle size D50 of the powder obtained by the sand grinding is 0.6 μm - 1.5 μm.
[0028] Preferably, the carbon removal treatment includes: carbon removal at 450 °C - 800 °C for 8 h - 18 h.
[0029] Preferably, the carbon removal treatment further includes drying before carbon removal: drying at a temperature of 80 °C - 180 °C for 6 h - 18 h.
[0030] In a second aspect, the present invention provides a modified barium titanate high-temperature ceramic material, and the modified barium titanate high-temperature ceramic material is prepared by the solid-phase sintering preparation method described in the first aspect.
[0031] In a third aspect, the present invention provides a high-temperature capacitor, and the high-temperature capacitor includes the modified barium titanate high-temperature ceramic material prepared by the solid-phase sintering preparation method described in the first aspect, or includes the modified barium titanate high-temperature ceramic material described in the second aspect.
[0032] The numerical ranges described in the present invention not only include the point values exemplified above, but also include any point values between the above numerical ranges not exemplified. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the ranges.
[0033] Compared with the prior art, the present invention has the following beneficial effects:
[0034] The solid-phase sintering preparation method provided by the present invention can improve the dielectric properties and high-temperature resistance of barium titanate ceramics in a high-temperature environment only by using simple auxiliary materials; moreover, the solid-phase sintering preparation method provided by the present invention is simple and easy to implement, and can realize the industrial-scale production of the modified barium titanate high-temperature ceramic material. Detailed Embodiments
[0035] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.
[0036] An embodiment of the present invention provides a solid-phase sintering preparation method for a modified barium titanate high-temperature ceramic material, and the solid-phase sintering preparation method includes:
[0037] Mix barium titanate powder and auxiliary material powder, and the obtained mixed powder is sintered to obtain the modified barium titanate high-temperature ceramic material;
[0038] The preparation raw materials of the auxiliary material powder include strontium carbonate, sodium carbonate and niobium pentoxide with a molar ratio of (7-9):1:(2-4).
[0039] The molar ratio of the barium titanate powder to the auxiliary material powder is 80:1-90:1. For example, it can be 80:1, 82:1, 85:1, 88:1 or 90:1, but is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable.
[0040] The molar ratio of strontium carbonate to sodium carbonate in the auxiliary material powder is (7-9):1. For example, it can be 7:1, 8:1 or 9:1, but is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable.
[0041] The molar ratio of sodium carbonate to niobium pentoxide in the auxiliary material powder is 1:(2-4). For example, it can be 1:2, 1:3 or 1:4, but is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable.
[0042] The solid-phase sintering preparation method provided by the present invention can improve the dielectric properties of barium titanate ceramics in a high-temperature environment only by using simple auxiliary materials; moreover, the solid-phase sintering preparation method provided by the present invention is simple and feasible, and can realize the industrial-scale production of modified barium titanate high-temperature ceramic materials.
[0043] In some embodiments, the heating rate of the sintering treatment is 2°C / min - 10°C / min. For example, it can be 2°C / min, 4°C / min, 5°C / min, 6°C / min, 8°C / min or 10°C / min, etc.
[0044] In some embodiments, the highest temperature of the sintering treatment is 1200°C - 1480°C. For example, it can be 1200°C, 1250°C, 1300°C, 1350°C, 1400°C, 1450°C or 1480°C, etc.
[0045] In some embodiments, the holding time at the highest temperature during the sintering process is 0.5 h - 3 h, for example, it can be 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, or 3 h, etc.
[0046] In some embodiments, the auxiliary material powder is prepared by the following solid-phase sintering preparation method: strontium carbonate, sodium carbonate, and niobium pentoxide are mixed according to the formula amount, the mixed powder is dried and carbon is removed, and then the auxiliary material is crushed to obtain the auxiliary material powder.
[0047] The solid-phase sintering preparation method provided by the present invention can make the particle size distribution of the obtained auxiliary material powder more concentrated by adopting a specific solid-phase sintering preparation method for the auxiliary material powder, so that the modified barium titanate high-temperature ceramic material has good high-temperature resistance and good dielectric properties under high-temperature environments.
[0048] The auxiliary material powder used in the present invention specifically selects strontium carbonate, sodium carbonate, and niobium pentoxide in specific proportions. When any one of the three auxiliary materials is missing, the technical effect of improving the high-temperature resistance of barium titanate ceramics cannot be achieved.
[0049] Among them, Sr in strontium carbonate can partially replace Ba in barium titanate to form a Sr-Ba solid solution, reduce the lattice distortion of the barium titanate ceramic material, and improve the stability; while Nb can compensate for the charge imbalance caused by the partial replacement of Ba by Sr and improve the grain boundary stability, thereby improving the high-temperature dielectric stability; the combined action of Sr and Nb improves the thermal stability of the barium titanate ceramic material through charge compensation and grain boundary matching; further, Na can reduce the grain coarsening during sintering, inhibit the formation of glass phase at the grain boundary, reduce the dielectric loss at high temperatures, and the use of Na can promote the uniform distribution of Sr and Nb, and the three work together to further improve the high-temperature resistance of the barium titanate ceramic material.
[0050] In some embodiments, the drying temperature is 80°C - 180°C (for example, it can be 80°C, 100°C, 120°C, 150°C, 160°C, or 180°C, etc.), and the time is 6 h - 18 h (for example, it can be 6 h, 8 h, 10 h, 12 h, 15 h, 16 h, or 18 h, etc.).
[0051] In some embodiments, the carbon removal temperature is 450°C - 800°C (for example, it can be 450°C, 500°C, 600°C, 700°C, or 800°C, etc.), and the time is 8 h - 18 h (for example, it can be 8 h, 10 h, 12 h, 15 h, 16 h, or 18 h, etc.).
[0052] In some embodiments, the barium titanate powder is prepared by the following solid-phase sintering preparation method: mixing a barium source and a titanium source to obtain a raw material powder; then performing a pre-sintering treatment on the raw material powder to obtain a pre-sintered blank; and sequentially performing a first crushing treatment, grinding, carbon removal treatment, and a second crushing treatment on the pre-sintered blank to obtain the barium titanate powder.
[0053] The solid-phase sintering preparation method provided by the present invention can make the median particle size distribution of the obtained barium titanate powder more concentrated by adopting a specific solid-phase sintering preparation method for the barium titanate powder, so that the modified barium titanate high-temperature ceramic material has good high-temperature resistance and good dielectric properties under high-temperature environments.
[0054] Among them, the pre-sintering treatment causes the titanium source and the barium source to undergo a solid-phase reaction and removes moisture, volatile impurities, gases, and some organic substances existing inside the raw materials, thereby improving the purity of the prepared barium titanate powder; in addition, the barium titanate powder obtained by the pre-sintering treatment better cooperates with the auxiliary material powder during subsequent sintering, so that the modified barium titanate high-temperature ceramic material has good dielectric properties under high-temperature environments.
[0055] In some embodiments, the barium source includes barium carbonate and / or barium oxide.
[0056] In some embodiments, the titanium source includes titanium dioxide.
[0057] In some embodiments, the median particle sizes of the barium source and the titanium source are independently 3 μm - 15 μm, and can be, for example, 3 μm, 5 μm, 8 μm, 10 μm, 12 μm, or 15 μm, etc.
[0058] In some embodiments, the molar ratio of Ba in the barium source to Ti in the titanium source is 0.990:1 - 1.010:1, and can be, for example, 0.990:1, 0.995:1, 1.000:1, 1.005:1, or 1.010:1, but is not limited to the listed values, and the other unlisted values within the numerical range are equally applicable.
[0059] In some embodiments, the median particle size D50 of the raw material powder is 0.8 μm - 3.5 μm, and can be, for example, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, or 3.5 μm, etc.
[0060] In order to obtain a raw material powder with a median particle size D50 satisfying 0.8 μm - 3.5 μm, the mixing of the barium source and the titanium source is first carried out in a three-dimensional mixer, and then an air flow crusher is used to obtain a raw material powder with a median particle size D50 satisfying 0.8 μm - 3.5 μm.
[0061] In some embodiments, the heating rate of the pre-sintering is 5°C / min - 10°C / min. For example, it can be 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, etc.
[0062] In the present invention, the starting temperature of the pre-sintering is room temperature, for example, it can be 15°C - 30°C, such as 15°C, 18°C, 20°C, 25°C, 28°C, 30°C, etc.
[0063] In some embodiments, the maximum temperature of the pre-sintering is 1150°C - 1350°C, etc.
[0064] In some embodiments, the holding time at the maximum temperature of the pre-sintering is 30 min - 180 min. For example, it can be 30 min, 50 min, 80 min, 100 min, 120 min, 150 min, 160 min, 180 min, etc.
[0065] In some embodiments, the method of the first crushing treatment includes depolymerization.
[0066] Exemplarily, the depolymerization is carried out in a jet mill.
[0067] In some embodiments, the median particle size D50 of the powder after the first crushing treatment is 0.8 μm - 3.5 μm. For example, it can be 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, etc.
[0068] In some embodiments, in order to obtain a powder with a median particle size D50 satisfying 0.8 μm - 3.5 μm by a jet mill and reduce the operating pressure of the jet mill, the first crushing treatment includes coarse crushing by a jaw crusher, fine crushing by a roll crusher, and depolymerization by a jet mill carried out in sequence. The "coarse crushing" and "fine crushing" herein are relative concepts, that is, the average median particle size of the material obtained by coarse crushing is larger than that of the material obtained by fine crushing.
[0069] In some embodiments, the method of the grinding includes sand grinding; the median particle size D50 of the powder obtained by the sand grinding is 0.6 μm - 1.5 μm, etc.
[0070] The present invention does not specifically limit parameters such as the method and time of the sand grinding, as long as the median particle size D50 of the powder obtained by the sand grinding is 0.6 μm - 1.5 μm. Generally speaking, controlling the sand grinding time to be 30 min - 180 min can achieve the technical effect that the median particle size D50 of the material obtained by the sand grinding is 0.6 μm - 1.5 μm.
[0071] Grinding can further refine the particle size of barium titanate powder. During the continuous refinement of its particle size, the specific surface area increases, which is beneficial for obtaining a dense modified barium titanate high-temperature ceramic material in subsequent sintering. However, during the continuous refinement of the particle size, fine particles re-aggregate under the influence of van der Waals forces, double-layer electrostatic interactions, etc. Therefore, as a preferred technical solution, a dispersant is used during grinding to prevent the mutual aggregation of barium titanate powders. Therefore, carbon removal treatment needs to be carried out after grinding to remove the dispersant.
[0072] The present invention does not specifically limit the dosage and type of the dispersant, as long as the dispersion effect during grinding can be achieved.
[0073] In some embodiments, the carbon removal treatment includes: performing carbon removal at 450°C - 800°C for 8h - 18h.
[0074] The temperature of the carbon removal is 450°C - 800°C, for example, it can be 450°C, 500°C, 600°C, 700°C, or 800°C, etc.
[0075] The time of the carbon removal is 8h - 18h, for example, it can be 8h, 10h, 12h, 15h, 16h, or 18h, etc.
[0076] In some embodiments, water is used as the sanding medium for sanding. Water has a good dispersion effect. During the sanding process, it adsorbs on the surface of solid particles, reducing the interfacial tension between liquid-liquid and solid-liquid, making the surface of aggregated solid particles easy to wet, and preventing the mutual aggregation of fine particles. However, the residual moisture is not conducive to subsequent sintering.
[0077] Preferably, the carbon removal treatment further includes drying before carbon removal: drying at a temperature of 80°C - 180°C for 6h - 18h.
[0078] The temperature of the drying is 80°C - 180°C, for example, it can be 80°C, 100°C, 120°C, 150°C, 160°C, or 180°C, etc.
[0079] The time of the drying is 6h - 18h, for example, it can be 6h, 8h, 10h, 12h, 15h, 16h, or 18h, etc.
[0080] An embodiment of the present invention provides a modified barium titanate high-temperature ceramic material, which is prepared by the solid-phase sintering preparation method described in any embodiment.
[0081] The present invention provides a high-temperature capacitor, which includes the modified barium titanate high-temperature ceramic material prepared by the solid-phase sintering preparation method described in any embodiment, or includes the modified barium titanate high-temperature ceramic material described in any embodiment.
[0082] To clearly illustrate the technical solution of the present invention, the normal temperature in the following specific embodiments is 25°C.
[0083] Example 1
[0084] This example provides a solid-phase sintering preparation method for a modified barium titanate high-temperature ceramic material, and the solid-phase sintering preparation method includes:
[0085] (1) Prepare barium titanate powder:
[0086] S11: Weigh barium carbonate (median particle size D50 is 10 μm) and titanium dioxide (median particle size D50 is 10 μm) according to a molar ratio of 1:1, perform preliminary mixing in a three-dimensional mixer, and then crush and mix the mixed raw materials through an air jet mill to obtain raw material powder with a median particle size D50 of 2 μm;
[0087] S12: Load the raw material powder into a crucible, vibrate and compact it on a vibrating table to make the material fully dense, then punch out exhaust ports with a uniform honeycomb arrangement, and place it in a muffle furnace for pre-sintering; the initial temperature during pre-sintering is normal temperature, the highest temperature is 1200°C, the heating rate is 8°C / min, keep the temperature at the highest temperature for heat preservation, and the heat preservation time is 120 min to obtain a pre-sintered blank;
[0088] S13: The pre-sintered blank is successively subjected to coarse crushing by a jaw crusher, fine crushing by a pair-roll crusher, and depolymerization by an air jet mill to obtain powder with a median particle size D50 of 2 μm; then perform sanding treatment to reduce the median particle size D50 of the powder to 1 μm;
[0089] S14: The sanded powder is dried at a temperature of 150°C for 10 h, and then carbon is removed at a temperature of 600°C for 12 h; then the powder after carbon removal is subjected to coarse crushing by a crusher and fine crushing by a pair-roll crusher to obtain barium titanate powder;
[0090] (2) Prepare auxiliary material powder:
[0091] S21: Weigh strontium carbonate (median particle size D50 is 10 μm), sodium carbonate (median particle size D50 is 10 μm), and niobium pentoxide (median particle size D50 is 10 μm) according to a molar ratio of 8:1:3, and mix them evenly in a ball mill;
[0092] S22: The evenly mixed powder is dried at a temperature of 150°C for 10 h, and then carbon is removed at a temperature of 600°C for 12 h; then the powder after carbon removal is subjected to coarse crushing by a crusher and fine crushing by a pair-roll crusher to obtain auxiliary material powder;
[0093] (3) Prepare the modified barium titanate high-temperature ceramic material
[0094] S31: The barium titanate powder obtained in step S14 and the auxiliary material powder obtained in step S24 are mixed in a jet mill in a depolymerization manner according to a molar ratio of 85:1 to obtain a mixed raw material powder;
[0095] S32: The raw material powder is filled into a crucible, vibrated and compacted on a vibrating table to make the material fully dense, and then exhaust ports arranged in a uniform honeycomb pattern are punched out and placed in a muffle furnace for sintering treatment; the initial temperature during sintering treatment is room temperature, the maximum temperature is 1400 °C, the heating rate is 8 °C / min, and when the maximum temperature is reached, heat preservation is carried out for 2 h to obtain the modified barium titanate high-temperature ceramic material.
[0096] Example 2
[0097] This example provides a solid-phase sintering preparation method for a modified barium titanate high-temperature ceramic material, and the solid-phase sintering preparation method includes:
[0098] (1) Preparation of barium titanate powder:
[0099] S11: Barium carbonate (median particle size D50 is 3 μm) and titanium dioxide (median particle size D50 is 3 μm) are weighed according to a molar ratio of 0.990:1, preliminarily mixed in a three-dimensional mixer, and then the mixed raw materials are crushed and mixed by a jet mill to obtain a raw material powder with a median particle size D50 of 0.8 μm;
[0100] S12: The raw material powder is filled into a crucible, vibrated and compacted on a vibrating table to make the material fully dense, and then exhaust ports arranged in a uniform honeycomb pattern are punched out and placed in a muffle furnace for pre-sintering; the initial temperature during pre-sintering is room temperature, the maximum temperature is 1150 °C, the heating rate is 5 °C / min, and when the maximum temperature is reached, heat preservation is carried out for 180 min to obtain a pre-sintered blank;
[0101] S13: The pre-sintered blank is successively subjected to coarse crushing by a jaw crusher, fine crushing by a pair-roll crusher, and depolymerization by a jet mill to obtain a powder with a median particle size D50 of 0.8 μm; then sanding treatment is carried out to reduce the median particle size D50 of the powder to 0.6 μm;
[0102] S14: The sanded powder is dried at 80 °C for 18 h, and then carbon is removed at 450 °C for 18 h; then the powder after carbon removal is subjected to coarse crushing by a crusher and fine crushing by a pair-roll crusher to obtain barium titanate powder;
[0103] (2) Preparation of auxiliary material powder:
[0104] S21: Weigh strontium carbonate (median particle size D50 is 3 μm), sodium carbonate (median particle size D50 is 3 μm), and niobium pentoxide (median particle size D50 is 3 μm) according to a molar ratio of 7:1:4, and mix them evenly in a ball mill;
[0105] S22: Dry the evenly mixed powder at 80 °C for 18 h, then remove carbon at 450 °C for 18 h; then coarsely crush the carbon-removed powder with a crusher and finely crush it with a roll crusher to obtain auxiliary material powder;
[0106] (3) Prepare the modified barium titanate high-temperature ceramic material
[0107] S31: Mix the barium titanate powder obtained in step S14 and the auxiliary material powder obtained in step S24 in a jet mill in a way of depolymerization according to a molar ratio of 80:1 to obtain a mixed raw material powder;
[0108] S32: Load the raw material powder into a crucible, vibrate and compact it on a vibrating compactor to make the material fully dense, then punch out exhaust ports with a uniform honeycomb arrangement, and put it into a muffle furnace for sintering treatment; the initial temperature during sintering treatment is room temperature, the highest temperature is 1200 °C, the heating rate is 2 °C / min, keep the temperature at the highest temperature for heat preservation, and the heat preservation time is 3 h to obtain the modified barium titanate high-temperature ceramic material.
[0109] Example 3
[0110] This example provides a solid-phase sintering preparation method for a modified barium titanate high-temperature ceramic material, and the solid-phase sintering preparation method includes:
[0111] (1) Prepare barium titanate powder:
[0112] S11: Weigh barium carbonate (median particle size D50 is 15 μm) and titanium dioxide (median particle size D50 is 15 μm) according to a molar ratio of 1.010:1, conduct preliminary mixing in a three-dimensional mixer, and then crush and mix the mixed raw materials with a jet mill to obtain raw material powder with a median particle size D50 of 3.5 μm;
[0113] S12: Load the raw material powder into a crucible, vibrate and compact it on a vibrating compactor to make the material fully dense, then punch out exhaust ports with a uniform honeycomb arrangement, and put it into a muffle furnace for pre-sintering; the initial temperature during pre-sintering is room temperature, the highest temperature is 1350 °C, the heating rate is 10 °C / min, keep the temperature at the highest temperature for heat preservation, and the heat preservation time is 30 min to obtain a pre-sintered blank;
[0114] S13: The pre-sintered blank is successively subjected to coarse crushing by a jaw crusher, fine crushing by a pair-roll crusher, and depolymerization by a jet mill to obtain a powder with a median particle size D50 of 3.5 μm; then it is subjected to sanding treatment to reduce the median particle size D50 of the powder to 1.5 μm;
[0115] S14: The sanded powder is dried at a temperature of 180 °C for 6 h, and then degassed at a temperature of 800 °C for 8 h; then the degassed powder is subjected to coarse crushing by a crusher and fine crushing by a pair-roll crusher to obtain barium titanate powder;
[0116] (2) Preparation of auxiliary material powder:
[0117] S21: Strontium carbonate (median particle size D50 is 15 μm), sodium carbonate (median particle size D50 is 15 μm), and niobium pentoxide (median particle size D50 is 15 μm) are weighed according to a molar ratio of 9:1:2 and mixed evenly in a ball mill;
[0118] S22: The evenly mixed powder is dried at a temperature of 180 °C for 6 h, and then degassed at a temperature of 800 °C for 8 h; then the degassed powder is subjected to coarse crushing by a crusher and fine crushing by a pair-roll crusher to obtain auxiliary material powder;
[0119] (3) Preparation of modified barium titanate high-temperature ceramic material
[0120] S31: The barium titanate powder obtained in step S14 and the auxiliary material powder obtained in step S24 are mixed in a jet mill in a depolymerization manner according to a molar ratio of 90:1 to obtain a mixed raw material powder;
[0121] S32: The raw material powder is filled into a crucible, vibrated and compacted on a vibrating table to make the material fully dense, and then exhaust holes arranged in a uniform honeycomb pattern are punched out and placed in a muffle furnace for sintering treatment; the initial temperature during the sintering treatment is room temperature, the highest temperature is 1480 °C, the heating rate is 10 °C / min, and heat preservation is carried out when the highest temperature is reached, and the heat preservation time is 0.5 h to obtain the modified barium titanate high-temperature ceramic material.
[0122] Example 4
[0123] This example provides a solid-phase sintering preparation method for barium titanate dielectric material. Except that the degassing temperature in step S14 is 400 °C, the rest are the same as in Example 1.
[0124] Example 5
[0125] This example provides a solid-phase sintering preparation method for barium titanate dielectric material. Except that the degassing temperature in step S14 is 850 °C, the rest are the same as in Example 1.
[0126] Example 6
[0127] This embodiment provides a solid-phase sintering preparation method of barium titanate dielectric material, which is the same as that of Example 1 except that step S14 is not carried out.
[0128] Example 7
[0129] This embodiment provides a solid-phase sintering preparation method of barium titanate dielectric material, which is the same as that of Example 1 except that the carbon removal temperature in step S22 is 400 °C.
[0130] Example 8
[0131] This embodiment provides a solid-phase sintering preparation method of barium titanate dielectric material, which is the same as that of Example 1 except that the carbon removal temperature in step S22 is 850 °C.
[0132] Example 9
[0133] This embodiment provides a solid-phase sintering preparation method of barium titanate dielectric material, which is the same as that of Example 1 except that step S22 is not carried out.
[0134] Comparative Example 1
[0135] This comparative example provides a solid-phase sintering preparation method of barium titanate ceramic material, which is the same as that of Example 1 except that the sanding in step S13 is not carried out.
[0136] Comparative Example 2
[0137] This comparative example provides a solid-phase sintering preparation method of barium titanate ceramic material, which is the same as that of Example 1 except that the auxiliary material powder is strontium carbonate and sodium carbonate with a molar ratio of 8:1.
[0138] Comparative Example 3
[0139] This comparative example provides a solid-phase sintering preparation method of barium titanate ceramic material, which is the same as that of Example 1 except that the auxiliary material powder is strontium carbonate and niobium pentoxide with a molar ratio of 8:3.
[0140] Comparative Example 4
[0141] This comparative example provides a solid-phase sintering preparation method of barium titanate ceramic material, which is the same as that of Example 1 except that the auxiliary material powder is sodium carbonate and niobium pentoxide with a molar ratio of 1:3.
[0142] Comparative Example 5
[0143] This comparative example provides a solid-phase sintering preparation method of barium titanate ceramic material, which is the same as that of Example 1 except that the auxiliary material powder is only strontium carbonate.
[0144] Comparative Example 6
[0145] This comparative example provides a solid-phase sintering preparation method for barium titanate ceramic materials. Except that the auxiliary powder is only sodium carbonate, the rest are the same as in Example 1.
[0146] Comparative Example 7
[0147] This comparative example provides a solid-phase sintering preparation method for barium titanate ceramic materials. Except that the auxiliary powder is only niobium pentoxide, the rest are the same as in Example 1.
[0148] Performance Characterization
[0149] The barium titanate ceramic materials obtained in the above examples and comparative examples were successively subjected to coarse crushing by a jaw crusher, fine crushing by a pair-roll crusher, and depolymerization by an air-flow pulverizer to obtain barium titanate ceramic particles with a median particle size D50 of 1 μm. Then, they were pressed into disc samples with a diameter of 30 mm and a thickness of 4 mm under a pressure of 20 MPa, and the dielectric properties of the disc samples were tested in the temperature range of -55°C to 200°C (dielectric constant ε r (F / m) and dielectric loss tanδ). The obtained results are shown in Table 1 and Table 2, where the temperature-capacitance change rate is the absolute value of the measured results.
[0150] Table 1
[0151]
[0152]
[0153] Table 2
[0154]
[0155] In summary, the solid-phase sintering preparation method provided by the invention can improve the dielectric properties and high-temperature resistance of barium titanate ceramics only by simple use of auxiliary materials; moreover, the solid-phase sintering preparation method provided by the invention is simple and feasible, and can realize the industrial-scale production of modified barium titanate high-temperature ceramic materials; moreover, the solid-phase sintering preparation method provided by the invention performs drying, carbon removal, and crushing treatments respectively when preparing barium titanate powder and auxiliary powder, improving the median particle size distribution of the raw materials, thereby improving the high-temperature resistance and dielectric properties of barium titanate ceramics in a high-temperature environment.
[0156] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.
Claims
1. A solid-phase sintering preparation method of a modified barium titanate high-temperature ceramic material, characterized in that, The solid-phase sintering preparation method includes: Mixing barium titanate powder and auxiliary material powder, and subjecting the obtained mixed powder to sintering treatment to obtain the modified barium titanate high-temperature ceramic material; The raw materials for preparing the auxiliary material powder include strontium carbonate, sodium carbonate, and niobium pentoxide with a molar ratio of (7-9):1:(2-4); The molar ratio of the barium titanate powder to the auxiliary material powder is 80:1 - 90:
1.
2. The solid-phase sintering preparation method according to claim 1, wherein The heating rate of the sintering treatment is 2°C / min - 10°C / min; And / or, the maximum temperature of the sintering treatment is 1200°C - 1480°C; And / or, the holding time at the maximum temperature of the sintering treatment is 0.5h - 3h.
3. The solid-phase sintering preparation method according to claim 1, characterized in that, The auxiliary material powder is prepared by the following solid-phase sintering preparation method: Mixing strontium carbonate, sodium carbonate, and niobium pentoxide according to the formula amount, drying and carbon removal of the mixed powder, and then performing auxiliary material crushing treatment to obtain the auxiliary material powder.
4. The solid-phase sintering preparation method according to claim 3, wherein The temperature of the drying is 80°C - 180°C, and the time is 6h - 18h; And / or, the temperature of the carbon removal is 450°C - 800°C, and the time is 8h - 18h.
5. The solid-phase sintering preparation method according to claim 1, wherein The barium titanate powder is prepared by the following solid-phase sintering preparation method: Mixing a barium source and a titanium source to obtain raw material powder; then subjecting the raw material powder to pre-sintering treatment to obtain a pre-sintered blank; the pre-sintered blank is successively subjected to first crushing treatment, grinding, carbon removal treatment, and second crushing treatment to obtain the barium titanate powder.
6. The solid-phase sintering preparation method according to claim 5, wherein, The median particle sizes of the barium source and the titanium source are independently 3μm - 15μm; And / or, the molar ratio of Ba in the barium source to Ti in the titanium source is 0.990:1 - 1.010:1; And / or, the median particle size D50 of the raw material powder is 0.8μm - 3.5μm.
7. The solid-phase sintering preparation method according to claim 5, characterized in that The heating rate of the pre-sintering is 5°C / min - 10°C / min; And / or, the maximum temperature of the pre-sintering is 1150°C - 1350°C; And / or, the holding time at the maximum temperature of the pre-sintering is 30min - 180min; And / or, the method of the first crushing treatment includes depolymerization; And / or, the median particle size D50 of the powder after the first crushing treatment is 0.8μm - 3.5μm.
8. The solid-phase sintering preparation method according to claim 5, characterized in that, The method of the grinding includes sand grinding; the median particle size D50 of the powder obtained by the sand grinding is 0.6μm - 1.5μm. And / or, the carbon removal treatment includes: performing carbon removal at 450°C - 800°C for 8h - 18h; And / or, the carbon removal treatment further includes drying before carbon removal: drying at a temperature of 80°C - 180°C for 6h - 18h.
9. A modified barium titanate high-temperature ceramic material, characterized in that, The modified barium titanate high-temperature ceramic material is prepared by the solid-phase sintering preparation method according to any one of claims 1 - 8.
10. A high-temperature capacitor, characterized in that, The high-temperature capacitor includes the modified barium titanate high-temperature ceramic material prepared by the solid-phase sintering preparation method according to any one of claims 1 - 8, or includes the modified barium titanate high-temperature ceramic material according to claim 9.