High-dielectric-constant temperature-stable dielectric ceramic material as well as preparation method and application thereof

Abstract

The invention provides a high-dielectric-constant temperature-stable dielectric ceramic material as well as a preparation method and application thereof. The ceramic dielectric material is prepared from the following raw materials: 15 mol% to 16 mol% of BaCO3 and / or BaO, 5 mol% to 15 mol% of Sm2O3, 5 mol% to 10 mol% of Bi2O3 and 60 mol% to 80 mol% of TiO2. The ceramic dielectric material provided by the invention has medium sintering temperature, high dielectric constant, low dielectric loss and high insulation resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of multifunctional electronic ceramic materials, and in particular relates to a high dielectric constant temperature-stable dielectric ceramic material and a preparation method and application thereof. Background Art

[0002] With the explosive growth of demand for wireless communication systems and consumer electronics markets, research on microwave dielectric ceramics in the field of microwave device applications (such as resonators, filters and oscillators) has received widespread attention. Among a large number of microwave dielectric materials, BaO-Ln2O3-TiO2 (Ln = Nd, Sm and La) has attracted much attention due to its high dielectric constant (k = 80 ~ 110), high quality factor (Q × f = 1800 ~ 10 000GHz) and tunable resonant frequency temperature coefficient (TCF). At present, the dielectric constant of ceramics used to prepare NP0 (C0G) ceramic capacitors is relatively small, generally not exceeding 100. In the BaO-Ln2O3-TiO2 system with a tungsten bronze structure, the dielectric constant of the material can be increased to more than 100 by doping with Pb ions, but it does not meet the ROHS standard. At present, the commonly used method is to select low-melting point glass or oxide as a sintering aid to achieve low-temperature dense sintering of ceramics, which is accompanied by a decrease in the dielectric constant of the ceramic, an increase in dielectric loss and a change in the dielectric temperature characteristics.

[0003] The dielectric ceramic materials and preparation processes need further improvement. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one object of the present invention is to provide a high dielectric constant temperature-stable dielectric ceramic material and a preparation method and application thereof. The dielectric ceramic material has a high dielectric constant, low dielectric loss and high insulation resistance.

[0005] In one aspect of the present invention, the present invention provides a high dielectric constant temperature-stable dielectric ceramic material. According to an embodiment of the present invention, the raw materials for forming the high dielectric constant temperature-stable dielectric ceramic material include: 15 mol% to 16 mol% of BaCO3 and / or BaO, 5 mol% to 15 mol% of Sm2O3, 5 mol% to 10 mol% of Bi2O3 and 60 mol% to 80 mol% of TiO2.

[0006] According to the high dielectric constant temperature-stable dielectric ceramic material of the above embodiment of the present invention, the raw materials for forming the high dielectric constant temperature-stable dielectric ceramic material include: 15 mol% of BaCO3 and / or BaO, 8 to 12 mol% of Sm2O3, 6 to 8 mol% of Bi2O3, and 67.5 mol% of TiO2.

[0007] According to a specific embodiment, the chemical formula of the provided high dielectric constant temperature-stable ceramic dielectric material can be written as a BaO-b Sm2O3-c Bi2O3-d TiO2, wherein a, b, c, and d independently represent mole percentages, wherein a is 15 mol% to 16 mol%, b is 5 mol% to 15 mol%, c is 5 mol% to 10 mol%, and d is 60 mol% to 80 mol%.

[0008] By using BaCO3 and / or BaO, Bi2O3, Sm2O3 and TiO2 to prepare a high dielectric constant temperature-stable dielectric ceramic material, and controlling the above raw materials within the above addition range, a C0G type dielectric ceramic material with high dielectric constant, low dielectric loss and high insulation resistance can be prepared. Specifically, the dielectric constant of the high dielectric constant temperature-stable dielectric ceramic material is 130 to 140, the dielectric loss is not greater than 0.0003, and the dielectric constant temperature coefficient is -30ppm / ℃ to +30ppm / ℃ in the range of -55 to 125℃, meeting the specification requirements of C0G type dielectric ceramics.

[0009] Another aspect of the present invention provides a method for preparing the above-mentioned high dielectric constant temperature-stable dielectric ceramic material. According to an embodiment of the present invention, it includes:

[0010] (1) BaCO3 and / or BaO, Bi2O3, Sm2O3 and TiO2 are mixed, ball-milled and dried to obtain a mixed material;

[0011] (2) pre-burning the mixed material to obtain a pre-burned material;

[0012] (3) mixing the pre-sintered material with a binder, granulating, tableting and debinding to obtain a ceramic green body;

[0013] (4) Sintering the ceramic green body to obtain a high dielectric constant temperature-stable dielectric ceramic.

[0014] Thus, the method can be used to prepare a high dielectric constant temperature-stable dielectric ceramic material, and the dielectric constant temperature coefficient of the dielectric ceramic material is -30ppm / ℃~+30ppm / ℃, which meets the specification requirements of C0G dielectric ceramics. Moreover, the provided method can be completed at a low sintering temperature without the need to add additional sintering aids or modifiers; and the precious rare earth components contained are low, which greatly reduces the production cost.

[0015] In addition, the method for preparing a high dielectric constant temperature-stable dielectric ceramic material according to the above embodiment of the present invention may also have the following technical features:

[0016] In some embodiments of the present invention, in step (1), the rotation speed of the ball mill is 150 r / min to 400 r / min, and the time is 6 h to 24 h.

[0017] In some embodiments of the present invention, in step (1), the drying temperature is 90°C to 200°C.

[0018] In some embodiments of the present invention, in step (2), the pre-firing temperature is 900° C. to 1200° C. and the time is 1 hour to 6 hours. Thus, the dielectric constant of the C0G dielectric ceramic material can be increased and the dielectric loss can be reduced.

[0019] In some embodiments of the present invention, in step (2), the heating rate of the pre-calcination is 2° C. / min to 10° C. / min.

[0020] In some embodiments of the present invention, in step (3), the temperature of the debinding is 500°C to 600°C, the time is 2h to 6h, and the heating rate of the debinding is 0.5°C / min to 5°C / min. Thus, the binder in the ceramic green body can be removed.

[0021] In some embodiments of the present invention, in step (4), the sintering temperature is 1220° C. to 1300° C. and the sintering time is 3 h to 7 h. Thus, the dielectric constant of the C0G dielectric ceramic material can be increased and the dielectric loss can be reduced.

[0022] In some embodiments of the present invention, in step (4), the heating rate of the sintering is 2° C. / min to 10° C. / min.

[0023] In the third aspect of the present invention, the present invention proposes the application of the above-mentioned high dielectric constant temperature-stable dielectric ceramic material or the dielectric ceramic material prepared by the above-mentioned method in the fields of communication, radar or electronics, including but not limited to laminated antennas, dielectric antennas, filters and resonators.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. DETAILED DESCRIPTION

[0025] Embodiments of the present invention are described in detail below. The embodiments are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0026] The present invention provides a high dielectric constant temperature-stable dielectric ceramic material, which is prepared by raw materials including the following substances: 15 mol% to 16 mol% of BaCO3 and / or BaO, 5 mol% to 15 mol% of Sm2O3, 5 mol% to 10 mol% of Bi2O3, and 60 mol% to 80 mol% of TiO2.

[0027] According to a specific embodiment, the chemical formula of the provided dielectric ceramic material is aBaO-bSm2O3-cBi2O3-dTiO2, wherein a, b, c, and d independently represent mole percentages, wherein a is 15 mol% to 16 mol%, b is 5 mol% to 15 mol%, c is 5 mol% to 10 mol%, and d is 60 mol% to 80 mol%.

[0028] The present invention proposes a method for preparing the above-mentioned high dielectric constant temperature-stable dielectric ceramic material, comprising:

[0029] S100: BaCO3 and / or BaO, Bi2O3, Sm2O3 and TiO2 are mixed, ball-milled and dried

[0030] In this step, BaCO3 and / or BaO, Bi2O3, Sm2O3 and TiO2 are weighed and mixed uniformly according to molar proportion, and then added into a ball mill for wet ball milling, the speed of the ball mill is 150r / min~400r / min, the time is 6h~24h, and a uniformly mixed powder is obtained, and then the powder is dried at a temperature of 90℃~200℃ to obtain a mixed material. It should be noted that ball milling is a conventional operation in this field, and those skilled in the art can select specific parameters of ball milling according to actual conditions, for example, the dispersant used in ball milling includes anhydrous ethanol or high-purity water, and the ball milling medium includes zirconia balls, steel balls, etc.

[0031] S200: Pre-burning the mixture

[0032] In this step, the mixed material obtained in S100 is pre-fired at a temperature of 900°C to 1200°C, the pre-fired time is 1h to 6h, and the pre-fired heating rate is 2°C / min to 10°C / min, thereby obtaining a pre-fired material. By controlling the pre-fired temperature and time and the pre-fired heating rate, the raw material particles are densified and have a certain reaction activity.

[0033] S300: Mix the pre-burned material with the binder, and then granulate, press and debind.

[0034] In this step, the pre-sintered material obtained in S200 is mixed with a binder, sieved to obtain granules, and the granules are granulated, tableted and debinded to obtain a ceramic green body. Furthermore, the debinding temperature is 500°C to 600°C, the time is 2h to 6h, and the debinding heating rate is 0.5°C / min to 5°C / min, so that the binder in the ceramic green body can be removed. Specifically, the binder includes at least one of a 5wt%-8wt% polyvinyl alcohol aqueous solution and a 5wt%-8wt% polyvinyl butyral ester ethanol solution.

[0035] S400: Sintering the ceramic green body

[0036] In this step, the ceramic green body obtained in S300 is sintered to obtain a C0G dielectric ceramic material. Further, the sintering temperature is 1220° C. to 1300° C., the time is 3 h to 7 h, and the sintering heating rate is 2° C. / min to 10° C. / min.

[0037] Therefore, the method can be used to prepare a high dielectric constant temperature type dielectric ceramic material, and the dielectric constant temperature coefficient of the dielectric ceramic material is -30ppm / °C to +30ppm / °C, meeting the specification requirements of C0G type dielectric ceramics.

[0038] The provided high dielectric constant temperature-stable dielectric ceramic material or the high dielectric constant temperature-stable dielectric ceramic material prepared by the above method can be used in multiple fields such as communications, radar or electronics, for example, including but not limited to laminated antennas, dielectric antennas, filters and resonators.

[0039] The present invention is described below with reference to specific examples, which are merely illustrative and do not limit the present invention in any way. Unless otherwise specified, the reagents used in the examples or comparative examples can be obtained commercially.

[0040] Example 1

[0041] Example 1 A high dielectric constant temperature-stable dielectric ceramic material is prepared by the following method, comprising:

[0042] (1) Mix BaCO3 powder, Bi2O3 powder, Sm2O3 powder and TiO2 powder according to the molar ratio. Among them, the molar ratio of BaCO3 powder is 15%, the molar ratio of Bi2O3 powder is 7%, the molar ratio of Sm2O3 powder is 10.5%, and the molar ratio of TiO2 powder is 67.5%. Add the weighed raw material powders into the ball mill for wet ball milling for 6 hours at a ball mill speed of 300r / min. The uniformly mixed powder is dried at 150 degrees Celsius to obtain a dried mixture;

[0043] (2) pre-calcining the dried mixed material at 1100°C for 3 hours at a heating rate of 5°C / min, and then naturally cooling the pre-calcined mixed powder after keeping the temperature;

[0044] (3) adding a binder (6 wt% polyvinyl alcohol aqueous solution) to the pre-sintered powder, mixing, sieving to obtain granules, granulating, tableting, and debinding the granules, wherein the debinding temperature is 550° C., the debinding time is 2 h, and the debinding heating rate is 3° C. / min to obtain a ceramic green body;

[0045] (4) The obtained ceramic green body was sintered at 1260° C. for 6 h with a sintering heating rate of 5° C. / min to obtain a high dielectric constant temperature-stable dielectric ceramic material.

[0046] The prepared dielectric ceramic material is characterized by X-ray diffraction, and its chemical formula is 15% BaO-10.5% Sm2O3-7% Bi2O3-67.5% TiO2.

[0047] Example 2

[0048] Example 2 A high dielectric constant temperature-stable dielectric ceramic material is prepared by the following method, comprising:

[0049] (1) Mix BaCO3 powder, Nd2O3 powder, Bi2O3 powder, Sm2O3 powder and TiO2 powder according to the molar ratio. Among them, the molar ratio of BaCO3 powder is 15%, the molar ratio of Bi2O3 powder is 7.9%, the molar ratio of Sm2O3 powder is 9.6%, and the molar ratio of TiO2 powder is 67.5%. Add the weighed raw material powders into the ball mill for wet ball milling for 6 hours at a ball mill speed of 300r / min. The uniformly mixed powder is dried at 150 degrees Celsius to obtain a dried mixture;

[0050] (2) pre-calcining the dried mixed material at 1100°C for 3 hours at a heating rate of 5°C / min, and then naturally cooling the pre-calcined mixed powder after keeping the temperature;

[0051] (3) adding a binder (6 wt% polyvinyl alcohol aqueous solution) to the pre-sintered powder, mixing, sieving to obtain granules, granulating, tableting, and debinding the granules, wherein the debinding temperature is 550° C., the debinding time is 2 h, and the debinding heating rate is 3° C. / min to obtain a ceramic green body;

[0052] (4) The obtained ceramic green body is sintered at 1260° C. for 6 hours with a sintering heating rate of 5° C. / min to obtain a high dielectric constant temperature-stable dielectric ceramic material.

[0053] The prepared dielectric ceramic material is characterized by X-ray diffraction, and its chemical formula is 15% BaO-9.6% Sm2O3-7.9% Bi2O3-67.5% TiO2.

[0054] Comparative Example 1

[0055] Comparative Example 1 provides a method for preparing a dielectric ceramic material. The difference between Comparative Example 1 and Example 1 lies in step (1) and step (4), which are respectively as follows:

[0056] (1) BaCO3 powder, Sm2O3 powder and TiO2 powder are mixed according to a molar ratio, wherein the molar ratio of BaCO3 powder is 15%, the molar ratio of Sm2O3 powder is 17.5%, and the molar ratio of TiO2 powder is 67.5%.

[0057] (4) The obtained ceramic green body was sintered at 1340°C for 6 h, with a sintering heating rate of 5°C / min.

[0058] The prepared dielectric ceramic material was characterized by X-ray diffraction, and its chemical formula was 15BaO-17.5Sm2O3-67.5TiO2.

[0059] Comparative Example 2

[0060] Comparative Example 2 provides a method for preparing a dielectric ceramic material. The difference between Comparative Example 2 and Example 1 lies in step (1) and step (4), which are respectively as follows:

[0061] (1) BaCO3 powder, Nd2O3 powder, Bi2O3 powder and TiO2 powder are mixed according to a molar ratio, wherein the molar ratio of BaCO3 powder is 15%, the molar ratio of Nd2O3 powder is 10.5%, the molar ratio of Bi2O3 powder is 7%, and the molar ratio of TiO2 powder is 67.5%.

[0062] (4) The obtained ceramic green body was sintered at 1260°C for 6 h, with a sintering heating rate of 5°C / min.

[0063] The prepared dielectric ceramic material is characterized by X-ray diffraction, and its chemical formula is 15% BaO-10.5% Nd2O3-7% Bi2O3-67.5% TiO2.

[0064] Comparative Example 3

[0065] Comparative Example 3 provides a method for preparing a dielectric ceramic material. The difference between Comparative Example 3 and Example 1 lies in step (1) and step (4), which are respectively as follows:

[0066] (1) BaCO3 powder, La2O3 powder, Bi2O3 powder and TiO2 powder are mixed according to a molar ratio, wherein the molar ratio of BaCO3 powder is 15%, the molar ratio of Nd2O3 powder is 10.5%, the molar ratio of Bi2O3 powder is 7%, and the molar ratio of TiO2 powder is 67.5%.

[0067] (4) The obtained ceramic green body was sintered at 1240°C for 6 h with a sintering heating rate of 5°C / min.

[0068] The prepared dielectric ceramic material is characterized by X-ray diffraction, and its chemical formula is 15% BaO-10.5% La2O3-7% Bi2O3-67.5% TiO2.

[0069] The composition and dosage of the high dielectric constant temperature-stable dielectric ceramic materials of the above-mentioned Examples 1-2 and Comparative Examples 1-3 are summarized in Table 1.

[0070] Table 1

[0071]

[0072]

[0073] The properties of the ceramic materials obtained in Examples 1-2 and Comparative Examples 1-3 were measured.

[0074] The ceramic material is tested for performance at 1V and 1MHz, including the dielectric constant, dielectric loss at 25℃, insulation resistivity at 25℃, insulation resistivity at 125℃, and dielectric temperature coefficient (TCC).

[0075] The dielectric constant, dielectric loss at 25°C, insulation resistivity at 25°C, and insulation resistivity at 125°C were all measured using methods known in the prior art, i.e., coating silver electrodes on both sides of the ceramic to conduct electrical performance tests;

[0076] The dielectric constant temperature coefficient TCC represents the degree of change of the capacitance of the material with temperature. It is calculated by testing the capacitance value at a temperature of -55℃ to 125℃ and using the following formula:

[0077]

[0078] Among them, T0 is the target test temperature.

[0079] The specific measurement results are shown in Table 2.

[0080] Table 2

[0081]

[0082] It can be seen from Table 2 that the dielectric ceramic of Example 1 has a larger dielectric constant and a smaller dielectric loss, and the dielectric constant temperature coefficient is -30ppm / °C to +30ppm / °C, and the dielectric constant temperature coefficient meets the requirements of the C0G type dielectric ceramic specification. This shows that the dielectric ceramic material of the present application has a high dielectric constant, low dielectric loss and high insulation resistance.

[0083] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific implementation", or "some implementations" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0084] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A high dielectric constant temperature-stable dielectric ceramic material, characterized in that: Prepared from raw materials including the following: 15 mol% to 16 mol% of BaCO3 and / or BaO, 5 mol% to 15 mol% Sm2O3, 5 mol% to 10 mol% Bi2O3, and 60 mol% to 80 mol% TiO2.

2. The high dielectric constant temperature-stable dielectric ceramic material according to claim 1, characterized in that: The raw materials for forming the high dielectric constant temperature-stable dielectric ceramic material include: 15 mol % of BaCO3 and / or BaO, 8-12 mol% Sm2O3, 6 to 8 mol% Bi2O3, and 67.5 mol% TiO2.

3. A high dielectric constant temperature-stable dielectric ceramic material, characterized in that: The general chemical formula of the high dielectric constant temperature-stable dielectric ceramic material is a BaO-b Sm2O3-c Bi2O3-d TiO2, wherein a, b, c, and d represent molar percentages independently. wherein a is 15 mol% to 16 mol%, b is 5 mol% to 15 mol%, c is 5 mol% to 10 mol%, and d is 60 mol% to 80 mol%.

4. The high dielectric constant temperature-stable dielectric ceramic material according to any one of claims 1 to 3, characterized in that: The high dielectric constant temperature-stable dielectric ceramic material has a dielectric constant of 130 to 140, a dielectric loss of no more than 0.0003, and a dielectric constant temperature coefficient of -30 ppm / °C to +30 ppm / °C.

5. A method for preparing the high dielectric constant temperature-stable dielectric ceramic material according to any one of claims 1 to 4, characterized in that: include: (1) BaCO3 and / or BaO, Sm2O3, Bi2O3 and TiO2 are mixed, ball-milled and dried to obtain a mixed material; (2) pre-burning the mixed material to obtain a pre-burned material; (3) mixing the pre-sintered material with a binder, granulating, tableting and debinding to obtain a ceramic green body; (4) Sintering the ceramic green body to obtain the high dielectric constant temperature-stable dielectric ceramic material.

6. The method according to claim 5, characterized in that In step (1), the rotation speed of the ball mill is 150 r / min to 400 r / min, and the time is 6 h to 24 h; Optionally, the drying temperature is 90°C to 200°C.

7. The method according to claim 5, characterized in that In step (2), the pre-burning temperature is 900° C. to 1200° C., and the time is 1 h to 6 h; Optionally, the heating rate of the pre-calcination is 2°C / min to 10°C / min.

8. The method according to claim 5, characterized in that In step (3), the debinding temperature is 500°C to 600°C, and the time is 2h to 6h; Optionally, the heating rate of the debinding process is 0.5°C / min to 5°C / min.

9. The method according to claim 5, characterized in that In step (4), the sintering temperature is 1200° C. to 1280° C., and the sintering time is 3 h to 7 h; Optionally, in step (4), the heating rate of the sintering is 2°C / min to 10°C / min.

10. Use of the high dielectric constant temperature-stable dielectric ceramic material according to any one of claims 1 to 4 or the high dielectric constant temperature-stable dielectric ceramic material prepared by the method according to any one of claims 5 to 9 in the fields of communications, radar or electronics.

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