High-dielectric low-loss dielectric material and preparation method thereof

Abstract

The invention discloses a high-dielectric low-loss dielectric material and a preparation method thereof, and relates to the technical field of electronic ceramic materials. Comprising the following components in parts by mole: 60 to 90 mol parts of barium titanate, 10 to 40 mol parts of potassium tantalate, 0.2 to 3 mol parts of bismuth oxide, 0.6 to 4 mol parts of titanium dioxide, 0.1 to 0.8 mol part of niobium pentoxide, 0.1 to 0.5 mol part of manganese carbonate and 0.2 to 0.6 mol part of vanadium pentoxide. The high-dielectric low-loss dielectric material disclosed by the invention is high in dielectric constant, low in dielectric loss and high in electric field resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic ceramic materials, and particularly to a high-dielectric low-loss dielectric material and a preparation method thereof. Background Art

[0002] In recent years, due to the huge demand for energy and the rapid development of microelectronics technology, the search for high-dielectric materials for electronic and energy storage devices has attracted wide attention in the industry. However, high-dielectric materials on the market often have relatively large dielectric losses. As is well known, high dielectric losses often lead to problems such as heating of devices or circuits, unstable operation, or signal attenuation, thus severely restricting the industrial production of ceramics. It can be seen that it is crucial to further reduce the dielectric loss while maintaining the high dielectric constant.

[0003] Lead-free barium titanate-based ceramic dielectric materials are one of the commonly used dielectric materials at present. However, the dielectric constant of this material is usually lower than 4000, with poor temperature stability, high sintering temperature, and it is impossible to balance various performance aspects such as loss. It is necessary to add additives to modify this dielectric material to increase the dielectric constant and reduce the dielectric loss.

[0004] Potassium tantalate (KTaO 3 ) single crystal has a stable cubic structure and can be used to make laser modulators, digital deflectors, and semiconductor devices. Since its crystal has no phase change in the temperature range from absolute zero to the melting point (1645K), it can be seen that its stability is extremely good. The dielectric constant of single crystal potassium tantalate can reach 4400+ and theoretically has the feasibility of being used as an additive to increase the dielectric constant and reduce the loss in lead-free barium titanate-based ceramic dielectrics.

[0005] To solve the above problems, a Chinese invention patent with the authorization announcement number CN106145932B discloses a high-dielectric constant multilayer ceramic capacitor dielectric material and a preparation method thereof. The composition chemical formula of the dielectric material is (1-n)Ba 1-y Ca y Ti 1-x Zr x O 3-n (Na 0.52 K 0.48 ) 1-m Li m NbO 3 , where 0≤x≤0.05, 0≤y≤0.05, 0<m≤0.06, 0.04≤n≤0.2. The dielectric material that can be used for multilayer ceramic capacitors has good temperature stability, high dielectric constant, low dielectric loss, and high technical reliability. However, its dielectric constant is still relatively low.

[0006] It can be seen that the development of a high-dielectric low-loss dielectric material with high dielectric constant, low dielectric loss, and high electric field strength resistance and its preparation method meet the market demand, have broad market value and application prospects, and are of great significance for promoting the development of the dielectric material field. Summary of the Invention

[0007] The purpose of the present invention is to provide a high-dielectric low-loss dielectric material with high dielectric constant, low dielectric loss, and high electric field strength resistance and its preparation method to overcome the deficiencies of the prior art.

[0008] To achieve the above object, the technical solution adopted by the present invention is: a high-dielectric low-loss dielectric material, which is made of the following components in terms of molar parts: 60-90 molar parts of barium titanate, 10-40 molar parts of potassium tantalate, 0.2-3 molar parts of bismuth oxide, 0.6-4 molar parts of titanium dioxide, 0.1-0.8 molar parts of niobium pentoxide, 0.1-0.5 molar parts of manganese carbonate, and 0.2-0.6 molar parts of vanadium pentoxide.

[0009] Another object of the present invention is to provide a preparation method for the high-dielectric low-loss dielectric material, which includes the following steps:

[0010] Step S1, prefabricating potassium tantalate: mixing tantalum pentoxide and potassium carbonate powders, performing ball milling, drying, and calcining with anhydrous ethanol as the dispersion medium, and sieving and granulating after taking out of the furnace to obtain KTO powder.

[0011] Step S2, preparing the dielectric material: mixing barium titanate, the KTO powder obtained in step S1, bismuth oxide, titanium dioxide, niobium pentoxide, manganese carbonate, and vanadium pentoxide, performing ball milling and mixing, drying, pulverizing, sieving through a standard sieve, granulating and pressing into a sheet with deionized water as the dispersion medium, degumming the formed body, and then sintering to obtain the dielectric material.

[0012] Preferably, in step S1, the molar ratio of the tantalum pentoxide to the potassium carbonate powder is 1:1.05.

[0013] Preferably, the ball milling time in step S1 is 6-8h.

[0014] Preferably, the drying time in step S1 is 2-6h, and the temperature is 85-120°C.

[0015] Preferably, the calcining temperature in step S1 is 1050-1120°C, and the time is 3-5h.

[0016] Preferably, the D50 of the KTO powder in step S1 is ≤0.5um.

[0017] Preferably, the ball milling time in step S2 is 4-10h.

[0018] Preferably, the pressure for tabletting in step S2 is 200 - 400 MPa.

[0019] Preferably, the particle size D50 after granulation in step S2 is ≤ 0.5 um.

[0020] Preferably, the temperature for debinding in step S2 is 500 - 600 °C, and the heat preservation time is 2 - 6 h.

[0021] Preferably, the temperature for sintering in step S2 is 1150 - 1250 °C, and the heat preservation time is 2 - 6 h.

[0022] Due to the application of the above technical solutions, the present invention has the following beneficial effects: Through the reasonable selection of the component formulation and preparation process parameters, the components of the present invention can cooperate with each other and work together, endowing the manufactured product with the advantages of low dielectric loss, high dielectric constant, and high electric field strength resistance. The introduction of barium titanate into potassium tantalate with a high dielectric constant solves the defects of its single use, and effectively reduces the dielectric loss on the basis of ensuring a high dielectric constant; the raw materials used do not contain elements harmful to the environment and humans such as lead, cadmium, mercury, and arsenic, making the preparation and use processes safer and more environmentally friendly. Specific Embodiments

[0023] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations.

[0024] Example 1

[0025] A high-dielectric low-loss dielectric material is made from the following components in mole fractions: 60 mole fractions of barium titanate, 38.8 mole fractions of potassium tantalate, 0.2 mole fractions of bismuth oxide, 0.6 mole fractions of titanium dioxide, 0.1 mole fractions of niobium pentoxide, 0.1 mole fractions of manganese carbonate, and 0.2 mole fractions of vanadium pentoxide.

[0026] A preparation method of the high-dielectric low-loss dielectric material includes the following steps:

[0027] Step S1, prefabricate potassium tantalate: Mix tantalum pentoxide and potassium carbonate powders, perform ball milling, drying, and calcination with anhydrous ethanol as the dispersion medium, and screen and granulate after taking out of the furnace to obtain KTO powder.

[0028] Step S2, preparation of the dielectric material: Mix barium titanate, the KTO powder obtained in step S1, bismuth oxide, titanium dioxide, niobium pentoxide, manganese carbonate, and vanadium pentoxide, perform ball milling and mixing, drying, pulverization, and screening through a standard sieve mesh with deionized water as the dispersion medium, then granulate and tablet, perform debinding on the formed body, and then sinter to obtain the dielectric material.

[0029] In step S1, the molar ratio of tantalum pentoxide to potassium carbonate powder is 1:1.05; the ball milling time in step S1 is 6 h; the drying time in step S1 is 3 h and the temperature is 100 °C; the calcination temperature in step S1 is 1050 °C and the time is 3 h; the D50 of the KTO powder in step S1 is ≤0.5 μm.

[0030] In step S2, the ball milling time is 4 h; the pressure for tabletting in step S2 is 200 MPa; the particle size D50 after granulation in step S2 is ≤0.5 μm; the debinding temperature in step S2 is 550 °C and the heat preservation time is 2 h; the sintering temperature in step S2 is 1250 °C and the heat preservation time is 2 h.

[0031] Example 2

[0032] A high-dielectric low-loss dielectric material is made of the following components in terms of molar parts: 70 molar parts of barium titanate, 26.8 molar parts of potassium tantalate, 1 molar part of bismuth oxide, 1.5 molar parts of titanium dioxide, 0.2 molar part of niobium pentoxide, 0.2 molar part of manganese carbonate, and 0.3 molar part of vanadium pentoxide.

[0033] A preparation method of the high-dielectric low-loss dielectric material comprises the following steps:

[0034] Step S1, prefabricating potassium tantalate: mixing tantalum pentoxide and potassium carbonate powder, carrying out ball milling, drying, and calcination with absolute ethanol as a dispersion medium, sieving and granulating after taking out of the furnace to obtain KTO powder;

[0035] Step S2, preparing the dielectric material: mixing barium titanate, the KTO powder obtained in step S1, bismuth oxide, titanium dioxide, niobium pentoxide, manganese carbonate, and vanadium pentoxide, carrying out ball milling and mixing, drying, pulverizing, sieving through a standard sieve mesh, then granulating and tabletting, carrying out debinding on the formed body, and then sintering to obtain the dielectric material.

[0036] In step S1, the molar ratio of tantalum pentoxide to potassium carbonate powder is 1:1.05; the ball milling time in step S1 is 6.5 h; the drying time in step S1 is 3 h and the temperature is 100 °C; the calcination temperature in step S1 is 1070 °C and the time is 3.5 h; the D50 of the KTO powder in step S1 is ≤0.5 μm.

[0037] The ball milling time in step S2 is 6 h; the pressure for tableting in step S2 is 250 MPa; the particle size D50 after granulation in step S2 is ≤ 0.5 um; the debinding temperature in step S2 is 550 °C, and the heat preservation time is 2.5 h; the sintering temperature in step S2 is 1230 °C, and the heat preservation time is 3 h.

[0038] Example 3

[0039] A high-dielectric low-loss dielectric material is made of the following components in terms of mole fraction: 75 mole fractions of barium titanate, 19.75 mole fractions of potassium tantalate, 1.5 mole fractions of bismuth oxide, 2.5 mole fractions of titanium dioxide, 0.5 mole fraction of niobium pentoxide, 0.35 mole fraction of manganese carbonate, and 0.4 mole fraction of vanadium pentoxide.

[0040] A preparation method of the high-dielectric low-loss dielectric material includes the following steps:

[0041] Step S1, prefabricating potassium tantalate: mixing tantalum pentoxide and potassium carbonate powders, performing ball milling, drying, and calcining with absolute ethanol as a dispersion medium, screening and granulating after taking out of the furnace to obtain KTO powder.

[0042] Step S2, preparing the dielectric material: mixing barium titanate, the KTO powder obtained in step S1, bismuth oxide, titanium dioxide, niobium pentoxide, manganese carbonate, and vanadium pentoxide, performing ball milling and mixing, drying, pulverizing, passing through a standard sieve, then granulating and tableting, performing debinding on the formed body, and then sintering to obtain the dielectric material.

[0043] The molar ratio of tantalum pentoxide to potassium carbonate powders in step S1 is 1:1.05; the ball milling time in step S1 is 7 h; the drying time in step S1 is 3 h, and the temperature is 100 °C; the calcining temperature in step S1 is 1090 °C, and the time is 4 h; the D50 of the KTO powder in step S1 is ≤ 0.5 um.

[0044] The ball milling time in step S2 is 7 h; the pressure for tableting in step S2 is 300 MPa; the particle size D50 after granulation in step S2 is ≤ 0.5 um; the debinding temperature in step S2 is 550 °C, and the heat preservation time is 3 h; the sintering temperature in step S2 is 1220 °C, and the heat preservation time is 3.5 h.

[0045] Example 4

[0046] A high-dielectric low-loss dielectric material is made of the following components in terms of molar parts: 85 molar parts of barium titanate, 7.4 molar parts of potassium tantalate, 2.5 molar parts of bismuth oxide, 3.5 molar parts of titanium dioxide, 0.7 molar parts of niobium pentoxide, 0.4 molar parts of manganese carbonate, and 0.5 molar parts of vanadium pentoxide.

[0047] A preparation method of the high-dielectric low-loss dielectric material comprises the following steps:

[0048] Step S1, prefabricating potassium tantalate: mixing tantalum pentoxide and potassium carbonate powders, carrying out ball milling, drying, and calcining with absolute ethanol as a dispersion medium, sieving and granulating after taking out of the furnace to obtain KTO powder;

[0049] Step S2, preparing the dielectric material: mixing barium titanate, the KTO powder obtained in step S1, bismuth oxide, titanium dioxide, niobium pentoxide, manganese carbonate, and vanadium pentoxide, carrying out ball milling and mixing, drying, pulverizing, sieving through a standard sieve mesh, granulating and pressing into a sheet, degumming the formed body, and then sintering to obtain the dielectric material.

[0050] In step S1, the molar ratio of the tantalum pentoxide to the potassium carbonate powder is 1:1.05; the ball milling time in step S1 is 7.5 h; the drying time in step S1 is 3 h and the temperature is 100 °C; the calcining temperature in step S1 is 1110 °C and the time is 4.5 h; the D50 of the KTO powder in step S1 is ≤0.5 μm.

[0051] In step S2, the ball milling time is 9 h; the pressure for pressing into a sheet in step S2 is 350 MPa; the particle size D50 after granulation in step S2 is ≤0.5 μm; the degumming temperature in step S2 is 550 °C and the heat preservation time is 3.5 h; the sintering temperature in step S2 is 1180 °C and the heat preservation time is 4 h.

[0052] Example Five

[0053] A high-dielectric low-loss dielectric material is made of the following components in terms of molar parts: 90 molar parts of barium titanate, 1.1 molar parts of potassium tantalate, 3 molar parts of bismuth oxide, 4 molar parts of titanium dioxide, 0.8 molar parts of niobium pentoxide, 0.5 molar parts of manganese carbonate, and 0.6 molar parts of vanadium pentoxide.

[0054] A preparation method of the high-dielectric low-loss dielectric material comprises the following steps:

[0055] Step S1, prefabricating potassium tantalate: mixing tantalum pentoxide and potassium carbonate powders, carrying out ball milling, drying, and calcining with absolute ethanol as a dispersion medium, sieving and granulating after taking out of the furnace to obtain KTO powder;

[0056] Step S2. Preparation of the dielectric material: Mix barium titanate, the KTO powder obtained in Step S1, bismuth oxide, titanium dioxide, niobium pentoxide, manganese carbonate, and vanadium pentoxide, and perform ball milling, drying, pulverizing, and sieving through a standard sieve using deionized water as the dispersion medium, followed by granulation and tableting. Then, degrease the formed body and sinter it to obtain the dielectric material.

[0057] In Step S1, the molar ratio of tantalum pentoxide to potassium carbonate powder is 1:1.05; the ball milling time in Step S1 is 8 h; the drying time in Step S1 is 24 h at a temperature of 95 °C; the calcination temperature in Step S1 is 1120 °C for 5 h; the D50 of the KTO powder in Step S1 is ≤0.5 μm.

[0058] In Step S2, the ball milling time is 10 h; the tableting pressure in Step S2 is 400 MPa; the particle size D50 after granulation in Step S2 is ≤0.5 μm; the degreasing temperature in Step S2 is 600 °C with a heat preservation time of 4 h; the sintering temperature in Step S2 is 1150 °C with a heat preservation time of 5 h.

[0059] Comparative Example 1

[0060] A high-dielectric low-loss dielectric material is basically the same as Example 1, except that an equal amount of barium titanate is used to replace the KTO powder.

[0061] Comparative Example 2

[0062] A high-dielectric low-loss dielectric material is basically the same as Example 1, except that manganese carbonate and vanadium pentoxide are not added.

[0063] To further illustrate the beneficial technical effects of the high-dielectric low-loss dielectric materials involved in the embodiments of the present invention, relevant performance tests were conducted on the high-dielectric low-loss dielectric materials involved in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1, and the test methods are as follows: Brush silver on both sides of the prepared high-dielectric low-loss dielectric material, sinter at 850 °C for 20 min to form silver electrodes, and use a Cuilient 4294A precision impedance analyzer and an E4980A LCR tester to measure the dielectric properties of the ceramic material respectively. For the withstand electric field strength Eb value, a high-voltage DC voltage is applied to the ceramic sample in silicone oil at room temperature using a Keithley 2410 digital source meter for I-V testing to obtain it.

[0064] Table 1

[0065]

[0066] As can be seen from Table 1, the high-dielectric-constant and low-loss dielectric materials involved in the embodiments of the present invention have a larger dielectric constant, lower dielectric loss, and higher electric field resistance than the products of the comparative examples. The combined use of KTO powder, manganese carbonate, and vanadium pentoxide has a beneficial effect on improving the above properties.

[0067] The above embodiments are only used to illustrate the technical concept and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A high dielectric and low loss dielectric material, characterized in that: The invention comprises the following components in molar parts: 60-90 molar parts of barium titanate, 10-40 molar parts of potassium tantalate, 0.2-3 molar parts of bismuth oxide, 0.6-4 molar parts of titanium dioxide, 0.1-0.8 molar parts of niobium pentoxide, 0.1-0.5 molar parts of manganese carbonate and 0.2-0.6 molar parts of vanadium pentoxide.

2. A method for preparing the high dielectric and low loss dielectric material according to claim 1, characterized in that: The steps include: Step S1, prefabricating potassium tantalate: mixing tantalum pentoxide and potassium carbonate powder, ball milling, drying and calcining with anhydrous ethanol as a dispersion medium, sieving and granulating after being taken out of the furnace to obtain KTO powder; Step S2, preparation of dielectric material: barium titanate, KTO powder obtained in step S1, bismuth oxide, titanium dioxide, niobium pentoxide, manganese carbonate, and vanadium pentoxide are mixed, ball-milled with deionized water as a dispersion medium, dried, crushed, sieved through a standard sieve, granulated, and tableted, the molded body is debinded, and then sintered to obtain a dielectric material.

3. The method for preparing a high dielectric and low loss dielectric material according to claim 2, characterized in that: The molar ratio of tantalum pentoxide to potassium carbonate powder in step S1 is 1:1.

05.

4. The method for preparing a high dielectric and low loss dielectric material according to claim 2, characterized in that: The ball milling time in step S1 is 6-8 hours.

5. The method for preparing a high dielectric and low loss dielectric material according to claim 2, characterized in that: The drying time in step S1 is 2-6 hours and the temperature is 85-120°C.

6. The method for preparing a high dielectric and low loss dielectric material according to claim 2, characterized in that: The calcination temperature in step S1 is 1050-1120° C. and the calcination time is 3-6 hours; the D50 of the KTO powder in step S1 is ≤0.5 um.

7. The method for preparing a high dielectric and low loss dielectric material according to claim 2, characterized in that: The ball milling time in step S2 is 4-10 hours.

8. The method for preparing a high dielectric and low loss dielectric material according to claim 2, characterized in that: The tableting pressure in step S2 is 200-400 MPa; the particle size D50 after granulation in step S2 is ≤ 0.5 um.

9. The method for preparing a high dielectric and low loss dielectric material according to claim 2, characterized in that: The debinding temperature in step S2 is 500-600° C., and the holding time is 2-6 hours.

10. The method for preparing a high dielectric and low loss dielectric material according to claim 2, characterized in that: The sintering temperature in step S2 is 1150-1250° C., and the holding time is 2-6 hours.

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