A barium titanate ceramic capacitor and its preparation method

Abstract

This invention relates to a barium titanate ceramic capacitor and its preparation method, belonging to the field of electronic component technology. The raw materials for its preparation include a main component, auxiliary materials, and sintering aids; the mass ratio of the main component, auxiliary materials, and sintering aids is (97-98):(1.5-2.5):(0.4-0.6); the main component is BaTiO3; the auxiliary materials are a mixture of Nb2O5, CoO, La2O3, CeO2, and MnO2; the molar ratio of Nb2O5, CoO, La2O3, CeO2, and MnO2 is 1:1:1:1:1. This barium titanate ceramic capacitor maintains excellent and stable dielectric properties over a wide temperature range.

Description

Technical Field

[0001] This invention relates to the field of electronic components technology, and in particular to a barium titanate ceramic capacitor and its preparation method. Background Technology

[0002] As electronic devices continue to evolve towards miniaturization and high performance, higher demands are being placed on the performance of electronic components. Ceramic capacitors, as commonly used energy storage components in electronic circuits, directly affect the stability and reliability of the entire circuit. Barium titanate ceramics, due to their high dielectric constant, are a commonly used matrix material for manufacturing ceramic capacitors. However, the dielectric constant, loss, and temperature stability of traditional barium titanate ceramic capacitors exhibit a seesaw effect, with some parameters increasing at one end and others decreasing at the other. It is difficult to guarantee that all indicators remain at a high level, especially under high-frequency operating conditions, where barium titanate ceramic capacitors that maintain high levels of performance across all parameters are lacking.

[0003] To address the aforementioned issues, some improvements have been implemented in existing technologies. For example, the performance of barium titanate ceramics can be improved by doping with other elements. Some studies have employed co-doping of barium titanate materials with donors (such as trivalent gadolinium ions, trivalent ytterbium ions, or pentavalent niobium ions) and acceptors (such as monovalent sodium ions or monovalent potassium ions), while simultaneously adding other additives (zirconia and zinc oxide) to form a formulation system. High-temperature solid-state reaction sintering is then used to prepare dielectric ceramics with wide temperature stability, high breakdown field strength, and high dielectric constant. However, while this method improves performance to some extent, the preparation process is complex, costly, and still has room for improvement in certain performance indicators. Other studies have introduced novel high-entropy components into the barium titanate matrix, such as Bi(Mg)2O3. 0.2 Ni 0.2 Zn 0.2 Zr 0.2 Nb 0.2 The multilayer ceramic capacitor prepared by introducing BaTiO3 (BT) into a solid solution of O3 (BMNZZN) exhibits good energy storage performance. However, this method has high requirements for raw materials and the preparation process is relatively complicated, which is not conducive to large-scale industrial production.

[0004] Therefore, developing a barium titanate ceramic capacitor that can maintain stable and excellent dielectric properties over a wide temperature range, while also having a simple and low-cost fabrication process, and its fabrication method, is of great practical significance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a barium titanate ceramic capacitor and its preparation method that can maintain stable and excellent dielectric properties over a wide temperature range, while having a simple and low-cost preparation process.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is a barium titanate ceramic capacitor, the raw materials for which preparation includes a main component, auxiliary materials and sintering aid; the mass ratio of the main component, auxiliary materials and sintering aid is (97-98):(1.5-2.5):(0.4-0.6); the main component is BaTiO3; the auxiliary materials are a mixture of Nb2O5, CoO, La2O3, CeO2 and MnO2.

[0007] Preferably, the molar ratio of Nb2O5, CoO, La2O3, CeO2, and MnO2 is 1:1:1:1:1.

[0008] Preferably, the sintering aid is BaO-SiO2-B2O3-ZrO2-ZnO glass.

[0009] Preferably, the molar ratio of BaO, SiO2, B2O3, ZrO2, and ZnO in the BaO-SiO2-B2O3-ZrO2-ZnO glass is 3:4:1:1:1.

[0010] Preferably, the raw materials for preparing the barium titanate ceramic capacitor also include vanadium pentoxide and indium oxide.

[0011] Preferably, the mass of vanadium pentoxide is 0.1-0.3% of the total mass of the raw materials.

[0012] Preferably, the mass of the indium oxide is 0.3-0.5% of the total mass of the raw materials.

[0013] Another object of the present invention is to provide a method for preparing the barium titanate ceramic capacitor, comprising the following steps: Step S1: Preparation of ceramic powder: Weigh each raw material according to the specified ratio, use anhydrous ethanol as the grinding medium, and put the weighed raw materials into a planetary ball mill for grinding and mixing; after grinding, dry the mixed slurry at 85-95℃ for 7-8 hours; then pass it through a 60-80 mesh sieve to obtain a uniformly mixed pre-made powder. Step S2, Powder Granulation and Green Body Forming: PVA aqueous solution is added dropwise to the pre-made powder and stirred thoroughly to make the PVA and powder evenly mixed; the granulated powder is pressed and formed using the electronic ceramic dry molding method to obtain a green body; the green body is heated to 550-650℃ and held for 0.7-0.9h for debinding. Step S3, Sintering of ceramics: After the ceramic blank is debinded, it is sintered at high temperature and then cooled in the furnace. After printing silver electrodes, barium titanate ceramic capacitors are obtained.

[0014] Preferably, the grinding and mixing time is 5-5.5 hours and the rotation speed is 370-380 r / min.

[0015] Preferably, the mass percentage concentration of the PVA aqueous solution is 7-8%.

[0016] Preferably, the mass ratio of the pre-formed powder to the PVA aqueous solution is 50:(3-4).

[0017] Preferably, the pressing pressure is 280-320 MPa.

[0018] Preferably, the high-temperature sintering temperature in step S3 is 1150-1250℃, and the holding time is 2.0-2.2h.

[0019] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) The preparation method of barium titanate ceramic capacitor disclosed in this invention is simple, easy to operate and control, has high preparation efficiency and finished product qualification rate, low dependence on equipment, easy to large-scale industrial production, and has high promotion and application value.

[0020] (2) The barium titanate ceramic capacitor disclosed in this invention is prepared using raw materials including a main component, auxiliary materials, and sintering aids; the mass ratio of the main component, auxiliary materials, and sintering aids is (97-98):(1.5-2.5):(0.4-0.6); the main component is BaTiO3; the auxiliary materials are a mixture of Nb2O5, CoO, La2O3, CeO2, and MnO2; the molar ratio of Nb2O5, CoO, La2O3, CeO2, and MnO2 is 1:1:1:1:1. Through the synergistic effect of the various raw materials, the prepared barium titanate ceramic capacitor has a dielectric constant of approximately 3500, a capacitance of 600pF, a loss of 0.8%, and a ceramic temperature coefficient that meets X7P at a high frequency of 1MHz. The introduced BaO-SiO2-B2O3-ZrO2-ZnO glass phase promotes ceramic densification, reduces porosity and defects, and, in synergy with optimized raw material formulation and preparation process, improves dielectric properties. A reasonable rare earth element doping ratio and the addition of indium oxide optimize carrier migration and polarization response, reduce energy loss at high frequencies, while the uniform microstructure ensures the stability of the dielectric constant.

[0021] (3) The barium titanate ceramic capacitor disclosed in this invention uses a BaO-SiO2-B2O3-ZrO2-ZnO glass phase to improve the density and uniformity of the ceramic. Combined with precise raw material ratio, molding pressure control and sintering process, the capacitance of the ceramic sheet can be stabilized at around 600pF. The pressure during green body molding ensures appropriate density, and the uniform structure formed during sintering reduces capacitance deviation.

[0022] (4) The barium titanate ceramic capacitor disclosed in this invention uses vanadium pentoxide (V2O5), which can prevent excessive reduction of barium titanate during sintering, ensure the stability of the electrical performance of the ceramic at high frequency, and reduce the increase in loss caused by reduction. Detailed Implementation

[0023] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. Example 1

[0024] A barium titanate ceramic capacitor is prepared from raw materials including a main component, auxiliary materials, and sintering aids; the mass ratio of the main component, auxiliary materials, and sintering aids is 97:1.5:0.4; the main component is BaTiO3; the auxiliary materials are a mixture of Nb2O5, CoO, La2O3, CeO2, and MnO2; the molar ratio of Nb2O5, CoO, La2O3, CeO2, and MnO2 is 1:1:1:1:1.

[0025] The sintering aid is BaO-SiO2-B2O3-ZrO2-ZnO glass; the molar ratio of BaO, SiO2, B2O3, ZrO2, and ZnO in the BaO-SiO2-B2O3-ZrO2-ZnO glass is 3:4:1:1:1; the raw materials for preparing the barium titanate ceramic capacitor also include vanadium pentoxide and indium oxide; the mass of vanadium pentoxide is 0.1% of the total mass of the raw materials; the mass of indium oxide is 0.3% of the total mass of the raw materials.

[0026] A method for preparing the barium titanate ceramic capacitor includes the following steps: Step S1: Preparation of ceramic powder: Weigh each raw material according to the specified ratio, use anhydrous ethanol as the grinding medium, and put the weighed raw materials into a planetary ball mill for grinding and mixing; after grinding, dry the mixed slurry at 85°C for 7 hours; then pass it through a 60-mesh sieve to obtain a uniformly mixed pre-made powder. Step S2, Powder Granulation and Green Body Forming: PVA aqueous solution is added dropwise to the pre-made powder and stirred thoroughly to make the PVA and powder evenly mixed; the granulated powder is pressed and formed using the electronic ceramic dry molding method to obtain a green body; the green body is heated to 550℃ and held at that temperature for 0.7h for debinding. Step S3, Sintering of ceramics: After the ceramic blank is debinded, it is sintered at high temperature and then cooled in the furnace. After printing silver electrodes, barium titanate ceramic capacitors are obtained.

[0027] The grinding and mixing time is 5 hours, and the rotation speed is 370 r / min; the mass percentage concentration of the PVA aqueous solution is 7%; the mass ratio of the pre-made powder to the PVA aqueous solution is 50:3; the pressing pressure is 280 MPa; the high-temperature sintering temperature in step S3 is 1150℃, and the holding time is 2.0 hours. Example 2

[0028] A barium titanate ceramic capacitor is prepared from raw materials including a main component, auxiliary materials, and sintering aids; the mass ratio of the main component, auxiliary materials, and sintering aids is 97.2:1.7:0.45; the main component is BaTiO3; the auxiliary materials are a mixture of Nb2O5, CoO, La2O3, CeO2, and MnO2; the molar ratio of Nb2O5, CoO, La2O3, CeO2, and MnO2 is 1:1:1:1:1.

[0029] The sintering aid is BaO-SiO2-B2O3-ZrO2-ZnO glass; the molar ratio of BaO, SiO2, B2O3, ZrO2, and ZnO in the BaO-SiO2-B2O3-ZrO2-ZnO glass is 3:4:1:1:1; the raw materials for preparing the barium titanate ceramic capacitor also include vanadium pentoxide and indium oxide; the mass of vanadium pentoxide is 0.15% of the total mass of the raw materials; the mass of indium oxide is 0.35% of the total mass of the raw materials.

[0030] A method for preparing the barium titanate ceramic capacitor includes the following steps: Step S1: Preparation of ceramic powder: Weigh each raw material according to the specified ratio, use anhydrous ethanol as the grinding medium, and put the weighed raw materials into a planetary ball mill for grinding and mixing; after grinding, dry the mixed slurry at 87℃ for 7.3h; then pass it through a 65-mesh sieve to obtain a uniformly mixed pre-made powder. Step S2, Powder Granulation and Green Body Forming: PVA aqueous solution is added dropwise to the pre-made powder and stirred thoroughly to make the PVA and powder evenly mixed; the granulated powder is pressed and formed using the electronic ceramic dry molding method to obtain a green body; the green body is heated to 580℃ and held at that temperature for 0.75h for debinding. Step S3, Sintering of ceramics: After the ceramic blank is debinded, it is sintered at high temperature and then cooled in the furnace. After printing silver electrodes, barium titanate ceramic capacitors are obtained.

[0031] The grinding and mixing time is 5.2 hours and the rotation speed is 373 r / min; the mass percentage concentration of the PVA aqueous solution is 7.2%; the mass ratio of the pre-made powder to the PVA aqueous solution is 50:3.2; the pressing pressure is 290 MPa; the high-temperature sintering temperature in step S3 is 1170℃ and the holding time is 2.1 hours. Example 3

[0032] A barium titanate ceramic capacitor is prepared from raw materials including a main component, auxiliary materials, and sintering aids; the mass ratio of the main component, auxiliary materials, and sintering aids is 97.5:2:0.5; the main component is BaTiO3; the auxiliary materials are a mixture of Nb2O5, CoO, La2O3, CeO2, and MnO2; the molar ratio of Nb2O5, CoO, La2O3, CeO2, and MnO2 is 1:1:1:1:1.

[0033] The sintering aid is BaO-SiO2-B2O3-ZrO2-ZnO glass; the molar ratio of BaO, SiO2, B2O3, ZrO2, and ZnO in the BaO-SiO2-B2O3-ZrO2-ZnO glass is 3:4:1:1:1; the raw materials for preparing the barium titanate ceramic capacitor also include vanadium pentoxide and indium oxide; the mass of vanadium pentoxide is 0.2% of the total mass of the raw materials; the mass of indium oxide is 0.4% of the total mass of the raw materials.

[0034] A method for preparing the barium titanate ceramic capacitor includes the following steps: Step S1: Preparation of ceramic powder: Weigh each raw material according to the specified ratio, use anhydrous ethanol as the grinding medium, and put the weighed raw materials into a planetary ball mill for grinding and mixing; after grinding, dry the mixed slurry at 90℃ for 7.5h; then pass it through a 70-mesh sieve to obtain a uniformly mixed pre-made powder. Step S2, Powder Granulation and Green Body Forming: PVA aqueous solution is added dropwise to the pre-made powder and stirred thoroughly to make the PVA and powder evenly mixed; the granulated powder is pressed and formed using the electronic ceramic dry molding method to obtain a green body; the green body is heated to 600℃ and held at that temperature for 0.8h for debinding. Step S3, Sintering of ceramics: After the ceramic blank is debinded, it is sintered at high temperature and then cooled in the furnace. After printing silver electrodes, barium titanate ceramic capacitors are obtained.

[0035] The grinding and mixing time is 5.3 hours and the rotation speed is 375 r / min; the mass percentage concentration of the PVA aqueous solution is 7.5%; the mass ratio of the pre-made powder to the PVA aqueous solution is 50:3.5; the pressing pressure is 300 MPa; the high-temperature sintering temperature in step S3 is 1200℃ and the holding time is 2.1 hours. Example 4

[0036] A barium titanate ceramic capacitor is prepared from raw materials including a main component, auxiliary materials, and sintering aids; the mass ratio of the main component, auxiliary materials, and sintering aids is 97.8:2.3:0.55; the main component is BaTiO3; the auxiliary materials are a mixture of Nb2O5, CoO, La2O3, CeO2, and MnO2; the molar ratio of Nb2O5, CoO, La2O3, CeO2, and MnO2 is 1:1:1:1:1.

[0037] The sintering aid is BaO-SiO2-B2O3-ZrO2-ZnO glass; the molar ratio of BaO, SiO2, B2O3, ZrO2, and ZnO in the BaO-SiO2-B2O3-ZrO2-ZnO glass is 3:4:1:1:1; the raw materials for preparing the barium titanate ceramic capacitor also include vanadium pentoxide and indium oxide; the mass of vanadium pentoxide is 0.25% of the total mass of the raw materials; the mass of indium oxide is 0.45% of the total mass of the raw materials.

[0038] A method for preparing the barium titanate ceramic capacitor includes the following steps: Step S1, Preparation of ceramic powder: Weigh each raw material according to the specified ratio, use anhydrous ethanol as the grinding medium, and put the weighed raw materials into a planetary ball mill for grinding and mixing; after grinding, dry the mixed slurry at 93℃ for 7.8h; then pass it through a 75-mesh sieve to obtain a uniformly mixed pre-made powder. Step S2, Powder Granulation and Green Body Forming: PVA aqueous solution is added dropwise to the pre-made powder and stirred thoroughly to make the PVA and powder evenly mixed; the granulated powder is pressed and formed using the electronic ceramic dry molding method to obtain a green body; the green body is heated to 640℃ and held at that temperature for 0.85h for debinding. Step S3, Sintering of ceramics: After the ceramic blank is debinded, it is sintered at high temperature and then cooled in the furnace. After printing silver electrodes, barium titanate ceramic capacitors are obtained.

[0039] The grinding and mixing time is 5.4 h, and the rotation speed is 378 r / min; the mass percentage concentration of the PVA aqueous solution is 7.8%; the mass ratio of the pre-made powder to the PVA aqueous solution is 50:3.8; the pressing pressure is 310 MPa; the high-temperature sintering temperature in step S3 is 1230℃, and the holding time is 2.2 h. Example 5

[0040] A barium titanate ceramic capacitor is prepared from raw materials including a main component, auxiliary materials, and sintering aids; the mass ratio of the main component, auxiliary materials, and sintering aids is 98:2.5:0.6; the main component is BaTiO3; the auxiliary materials are a mixture of Nb2O5, CoO, La2O3, CeO2, and MnO2; the molar ratio of Nb2O5, CoO, La2O3, CeO2, and MnO2 is 1:1:1:1:1.

[0041] The sintering aid is BaO-SiO2-B2O3-ZrO2-ZnO glass; the molar ratio of BaO, SiO2, B2O3, ZrO2, and ZnO in the BaO-SiO2-B2O3-ZrO2-ZnO glass is 3:4:1:1:1; the raw materials for preparing the barium titanate ceramic capacitor also include vanadium pentoxide and indium oxide; the mass of vanadium pentoxide is 0.3% of the total mass of the raw materials; the mass of indium oxide is 0.5% of the total mass of the raw materials.

[0042] A method for preparing the barium titanate ceramic capacitor includes the following steps: Step S1: Preparation of ceramic powder: Weigh each raw material according to the specified ratio, use anhydrous ethanol as the grinding medium, and put the weighed raw materials into a planetary ball mill for grinding and mixing; after grinding, dry the mixed slurry at 95°C for 8 hours; then pass it through an 80-mesh sieve to obtain a uniformly mixed pre-made powder. Step S2, Powder Granulation and Green Body Forming: PVA aqueous solution is added dropwise to the pre-made powder and stirred thoroughly to make the PVA and powder evenly mixed; the granulated powder is pressed and formed using the electronic ceramic dry molding method to obtain a green body; the green body is heated to 650℃ and held at that temperature for 0.9h for debinding. Step S3, Sintering of ceramics: After the ceramic blank is debinded, it is sintered at high temperature and then cooled in the furnace. After printing silver electrodes, barium titanate ceramic capacitors are obtained.

[0043] The grinding and mixing time is 5.5 hours and the rotation speed is 380 r / min; the mass percentage concentration of the PVA aqueous solution is 8%; the mass ratio of the pre-made powder to the PVA aqueous solution is 50:4; the pressing pressure is 320 MPa; the high-temperature sintering temperature in step S3 is 1250℃ and the holding time is 2.2 hours.

[0044] Comparative Example 1 A barium titanate ceramic capacitor and its preparation method are basically the same as those in Example 1, except that an equal amount of Nb2O5 is used instead of CeO2 and no vanadium pentoxide is added.

[0045] Comparative Example 2 A barium titanate ceramic capacitor and its preparation method are basically the same as those in Example 1, except that an equal amount of La2O3 is used instead of CeO2, and no indium oxide is added.

[0046] To further illustrate the beneficial technical effects of the barium titanate ceramic capacitors involved in the various embodiments of the present invention, relevant performance tests were conducted on the barium titanate ceramic capacitors involved in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1. The test methods are as follows: Dielectric performance tests were conducted using an Agilent 4294A precision impedance analyzer and an E4980A LCR tester, respectively.

[0047] Table 1. Test results of barium titanate ceramic capacitor performance In the temperature range of -55℃ to 125℃, the capacitance value change was tested using a high and low temperature chamber and an LCR tester. The results showed that the capacitance change rate of the products in Examples 1-5 was between -15% and +15%, which met the X7R temperature coefficient requirements; while the comparative documents 1-2 did not meet the X7R temperature coefficient requirements.

[0048] The experimental results show that the barium titanate ceramic capacitors described in this invention maintain superior and more stable dielectric properties over a wider temperature range compared to the comparative products. The combined use of Nb₂O₅, CeO₂, vanadium pentoxide, La₂O₃, CeO₂, and indium oxide is beneficial for improving these properties.

[0049] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A barium titanate ceramic capacitor, characterized in that, The raw materials for its preparation include main components, auxiliary materials and sintering aids; the mass ratio of the main components, auxiliary materials and sintering aids is (97-98):(1.5-2.5):(0.4-0.6); the main component is BaTiO3; the auxiliary materials are a mixture of Nb2O5, CoO, La2O3, CeO2 and MnO2.

2. The barium titanate ceramic capacitor according to claim 1, characterized in that, The molar ratio of Nb2O5, CoO, La2O3, CeO2, and MnO2 is 1:1:1:1:

1.

3. The barium titanate ceramic capacitor according to claim 1, characterized in that, The sintering aid is BaO-SiO2-B2O3-ZrO2-ZnO glass.

4. The barium titanate ceramic capacitor according to claim 3, characterized in that, The molar ratio of BaO, SiO2, B2O3, ZrO2, and ZnO in the BaO-SiO2-B2O3-ZrO2-ZnO glass is 3:4:1:1:

1.

5. The barium titanate ceramic capacitor according to claim 1, characterized in that, The raw materials for preparing the barium titanate ceramic capacitor also include vanadium pentoxide and indium oxide.

6. The barium titanate ceramic capacitor according to claim 5, characterized in that, The mass of vanadium pentoxide is 0.1-0.3% of the total mass of the raw materials; the mass of indium oxide is 0.3-0.5% of the total mass of the raw materials.

7. A method for preparing a barium titanate ceramic capacitor according to any one of claims 1-6, characterized in that, Includes the following steps: Step S1: Preparation of ceramic powder: Weigh each raw material according to the ratio, use anhydrous ethanol as the grinding medium, and put the weighed raw materials into a planetary ball mill for grinding and mixing. After grinding, the mixed slurry is dried at 85-95℃ for 7-8 hours; then it is passed through a 60-80 mesh sieve to obtain a uniformly mixed pre-mixed powder. Step S2, Powder Granulation and Green Body Forming: PVA aqueous solution is added dropwise to the pre-made powder and stirred thoroughly to make the PVA and powder evenly mixed; the granulated powder is pressed and formed using the electronic ceramic dry molding method to obtain a green body; the green body is heated to 550-650℃ and held for 0.7-0.9h for debinding. Step S3, Sintering of ceramics: After the ceramic blank is debinded, it is sintered at high temperature and then cooled in the furnace. After printing silver electrodes, barium titanate ceramic capacitors are obtained.

8. The method for preparing a barium titanate ceramic capacitor according to claim 7, characterized in that, The grinding and mixing time is 5-5.5 hours, and the rotation speed is 370-380 r / min; the mass percentage concentration of the PVA aqueous solution is 7-8%.

9. The method for preparing a barium titanate ceramic capacitor according to claim 7, characterized in that, The mass ratio of the pre-formed powder to the PVA aqueous solution is 50:(3-4).

10. The method for preparing a barium titanate ceramic capacitor according to claim 7, characterized in that, The pressing pressure is 280-320 MPa; the high-temperature sintering temperature in step S3 is 1150-1250℃, and the holding time is 2.0-2.2 h.

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