High dielectric ceramic capacitor and preparation method thereof

Abstract

The present invention provides a high-dielectric ceramic capacitor and a preparation method thereof. The preparation method comprises: S1: mixing BaCO3 and TiO2 powder materials, adding Nb2O5 and Gd2O3, and sintering to obtain a BaTiO3 base material doped with Nb and Gd; S2: mixing BaCO3, B2O3, and MnO, and sintering to obtain an additive; S3: mixing the doped BaTiO3 base material with the additive, debinding, and sintering in sequence to obtain a BaTiO3 ceramic. The high-dielectric ceramic capacitor of the present invention can store more charge due to its extremely high dielectric constant, thereby improving capacitance performance and facilitating capacitor miniaturization; its significant temperature stability and low loss enable the ceramic capacitor to maintain stable electrical performance under extreme temperature conditions, providing more reliable protection for electronic devices based thereon; the high-dielectric ceramic capacitor of the present invention does not contain any components harmful to the human body and the environment during the sintering process, is green and environmentally friendly, and has low cost, achieving the dual advantages of economic efficiency and environmental friendliness.

Description

Technical Field

[0001] The present invention relates to the field of ceramic capacitors, and in particular to a high-dielectric ceramic capacitor and a preparation method thereof. Background Art

[0002] Ceramic capacitors, a crucial component in electronic devices, are common passive devices used in a wide range of electronic devices. As electronic devices become increasingly smaller and lighter, the demand for smaller components is also increasing, significantly increasing the demand for high-k dielectric constant ceramic capacitors. While pursuing high dielectric constants to achieve high capacitance in a compact size, technicians also employ appropriate doping to achieve ideal electrical performance. Commonly used standards for measuring the temperature stability of ceramic capacitors include X7R, X7P, and X8R, X8P. X7R and X7P specify a capacitance change rate of less than 15% and 10%, respectively, within the temperature range of -55°C to 125°C. X8R and X8P specify a capacitance change rate of less than 15% and 10%, respectively, within the temperature range of -55°C to 150°C. X8R ceramic capacitors offer excellent capacitance stability and a higher dielectric constant, resulting in less significant performance changes with temperature, voltage, and time, resulting in a high dielectric constant and low capacitance change. The "X" designates a temperature of -55°C, the "8" designates a temperature of 150°C, and the "R" designates that within the temperature range of -55°C to 150°C, the difference between the capacitance at room temperature (25°C) and the capacitance at -55°C and 150°C divided by the capacitance at 25°C must be ≤15%. This means the capacitance-temperature variation must be no greater than 15%. X8P ceramic capacitors offer even better temperature stability, requiring a capacitance-temperature variation of no more than 10%.

[0003] Current research on the temperature stability of high-k dielectric ceramic capacitors primarily focuses on the X7R standard, while existing research on materials with higher temperature stability than the X7R standard has primarily focused on low-k dielectric constant materials. However, with the recent development of aerospace, oil drilling, and other fields, the X7R dielectric ceramics currently widely used in electronic communications equipment and sensors are no longer able to meet the requirements of these electronic devices, which require high temperature stability. At the same time, the demand for capacitors with small size and high capacity in these fields also requires high-k dielectric constant materials.

[0004] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art.

[0005] In view of the above, there is an urgent need to provide a high dielectric ceramic capacitor and a preparation method thereof that meet the X8P requirements of the electronics industry standard to achieve high temperature stability of electronic devices. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a high dielectric constant ceramic capacitor with high temperature stability, high dielectric constant and low loss and a preparation method thereof, so as to solve the problems of poor temperature stability in the prior art.

[0007] To achieve the above-mentioned and other related objectives, the present invention provides a method for preparing a high-dielectric ceramic capacitor, the method comprising at least:

[0008] S1: BaCO3 and TiO2 powder materials are mixed, and Nb2O5 and Gd2O3 are added, and sintered to obtain a BaTiO3 base material doped with Nb and Gd;

[0009] S2: Mix BaCO3, B2O3 and MnO and sinter to obtain an additive;

[0010] S3: mixing the doped BaTiO3 base material with the auxiliary agent, and sequentially performing debinding and sintering to obtain BaTiO3 ceramics.

[0011] Optionally, in step S1, the specific steps of preparing the BaTiO3 base material doped with Nb and Gd include:

[0012] S11: mixing BaCO3 and TiO2 powder materials in a molar ratio of 1:1;

[0013] S12: adding 1% to 3% of Nb2O5 and 0.1% to 0.2% of Gd2O3 to the powder material;

[0014] S13: using deionized water as solvent and ZrO2 balls as ball milling media, the powder material is ball milled in a nylon jar, the ratio of powder material: ZrO2 balls: deionized water is 1:4:1, and the ball milling time is 6 hours;

[0015] S14: The ball-milled mixture is placed in an oven for drying and passed through a 50-mesh sieve;

[0016] S15: Sintering the sieved mixed material in air to obtain the BaTiO3 base material doped with Nb and Gd.

[0017] Optionally, in step S12, 2% Nb2O5 is added to the powder material.

[0018] Optionally, in step S12, 0.15% of Gd2O3 is added to the powder material.

[0019] Optionally, in step S15, the sintering temperature is 1100° C. to 1300° C., and the sintering time is 1 hour to 3 hours.

[0020] Optionally, in step S2, the specific steps of obtaining the auxiliary agent include:

[0021] S21: BaCO3, B2O3 and MnO are mixed in a mass ratio of 10: (0.5-2): (2-4);

[0022] S22: Sintering the mixed material in step S21 in air to obtain an additive.

[0023] Optionally, in step S21, BaCO3, B2O3 and MnO are mixed in a mass ratio of 10:1:3.

[0024] Optionally, in step S22, the sintering temperature is 700°C to 900°C, and the sintering time is 1 hour to 3 hours.

[0025] Optionally, in step S3, the specific steps of obtaining the BaTiO3 ceramic include:

[0026] S31: mixing the doped BaTiO3 base material and the auxiliary agent in a mass ratio of (97-99): (3-1);

[0027] S32: Using deionized water as a solvent and ZrO2 balls as a ball milling medium, the mixed material in step S31 is ball milled in a nylon jar, with the ratio of mixed material: ZrO2 balls: deionized water being 1:4:1.5;

[0028] S33: adding 2% by mass of SiO2 sol to the ball milled material in step S32 for granulation;

[0029] S34: dry pressing under a pressure of 20 MPa, and keeping the green body at 600°C for 2 hours for debinding;

[0030] S35: Sintering the debinded green body in air to obtain the BaTiO3 ceramic.

[0031] Optionally, in step S31, the doped BaTiO3 base material and the auxiliary agent are mixed in a mass ratio of 98:2.

[0032] Optionally, in step S35, the sintering temperature is 1200°C to 1300°C, and the sintering time is 1.5h to 2.5h.

[0033] Optionally, the method for preparing the high dielectric ceramic capacitor further includes:

[0034] S4: forming an electrode layer on the surface of the BaTiO3 ceramic using a screen printing technique;

[0035] S5: forming solder pins on the electrode layer;

[0036] S6: Encapsulating the BaTiO3 ceramic to form a ceramic capacitor.

[0037] The present invention also provides a high dielectric ceramic capacitor, which is prepared by any one of the above-mentioned methods for preparing a high dielectric ceramic capacitor.

[0038] As described above, the high dielectric ceramic capacitor and the preparation method thereof of the present invention have the following beneficial effects:

[0039] The BaTiO3 system high dielectric ceramic capacitor prepared by the high dielectric ceramic capacitor preparation method of the present invention has a dielectric constant of 2000-2200, a loss value <1.5%, and a capacitance temperature change rate |Δε| / ε 25 ≤10%, and the insulation resistivity is around 500GΩ at 1.0kHz, fully meeting the X8P requirements of the electronics industry standard. High-dielectric ceramic capacitors can store more charge due to their extremely high dielectric constant, thereby improving capacitance performance. This means that at the same capacitance value, the high-dielectric ceramic capacitors of the present invention can be made smaller, which is conducive to the miniaturization of capacitors; the significant temperature stability and low loss enable ceramic capacitors to maintain stable electrical performance under extreme temperature conditions, providing more reliable protection for electronic devices based on them; the high-dielectric ceramic capacitors of the present invention do not contain components that are harmful to the human body and the environment during the sintering process, such as volatile or heavy metal components such as lead and cadmium, ensuring the green and environmentally friendly characteristics of the material, and greatly reducing production costs, achieving the dual advantages of economic benefits and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic flow chart showing the method for preparing a high dielectric ceramic capacitor according to the present invention.

[0041] Figure 2 It is a schematic flow chart showing step S1 of the method for preparing a high dielectric ceramic capacitor according to the present invention.

[0042] Figure 3 It is a schematic flow chart showing step S2 of the method for preparing a high dielectric ceramic capacitor according to the present invention.

[0043] Figure 4It is a schematic flow chart showing step S3 of the method for preparing a high dielectric ceramic capacitor according to the present invention.

[0044] Figure 5 Shown is a schematic diagram of the overall process of the high dielectric ceramic capacitor preparation method of the present invention. DETAILED DESCRIPTION

[0045] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0046] For example, when describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional views showing the device structures will not be partially enlarged according to the general scale, and the schematic views are only examples and should not limit the scope of protection of the present invention.

[0047] For ease of description, spatially relative terms such as "under," "below," "below," "below," "above," and "on" may be used herein to describe the relationship of one structure or feature shown in the drawings to other structures or features. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the drawings. Additionally, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. As used herein, "between" is inclusive of both endpoints.

[0048] In the context of the present application, a structure described as a first feature being "above" a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where an additional feature is formed between the first and second features, such that the first and second features may not be in direct contact.

[0049] See also Figures 1 to 5 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0050] like Figure 1 As shown, this embodiment provides a method for preparing a high dielectric ceramic capacitor, and the method for preparing a high dielectric ceramic capacitor at least includes:

[0051] S1: BaCO3 and TiO2 powder materials are mixed, and Nb2O5 and Gd2O3 are added, and sintered to obtain BaTiO3 base material doped with Nb and Gd;

[0052] S2: Mix BaCO3, B2O3 and MnO and sinter to obtain an additive;

[0053] S3: The doped BaTiO3 base material is mixed with an additive, and debinding and sintering are performed in sequence to obtain BaTiO3 ceramics.

[0054] The following combination Figures 1 to 4 , specifically explain the preparation method of high dielectric ceramic capacitors.

[0055] like Figure 1 and Figure 2 As shown, in an practicable specific example, in step S1, the specific steps of preparing a BaTiO3 base material doped with Nb and Gd include:

[0056] S11: mixing BaCO3 and TiO2 powder materials in a molar ratio of 1:1;

[0057] S12: adding 1% to 3% Nb2O5 and 0.1% to 0.2% Gd2O3 to the powder material;

[0058] S13: Using deionized water as solvent and ZrO2 balls as ball milling media, the powder material is ball milled in a nylon jar. The ratio of powder material: ZrO2 balls: deionized water is 1:4:1, and the ball milling time is 6 hours.

[0059] S14: The ball-milled mixture is placed in an oven for drying and passed through a 50-mesh sieve;

[0060] S15: Sintering the sieved mixture in air to obtain a BaTiO3 base material doped with Nb and Gd.

[0061] Furthermore, in step S12, 2% Nb2O5 is added to the powder material.

[0062] Furthermore, in step S12, 0.15% of Gd2O3 is added to the powder material.

[0063] Furthermore, in step S15, the sintering temperature is 1100° C. to 1300° C., and the sintering time is 1 hour to 3 hours. Preferably, in step S15, the sintering temperature is 1200° C., and the sintering time is 2 hours.

[0064] like Figure 1 and Figure 3 As shown, in a specific example that can be implemented, in step S2, the specific steps of obtaining the auxiliary agent include:

[0065] S21: BaCO3, B2O3 and MnO are mixed in a mass ratio of 10: (0.5-2): (2-4);

[0066] S22: Sintering the mixed material in step S21 in air to obtain an additive.

[0067] Further, in step S21, BaCO3, B2O3 and MnO are mixed in a mass ratio of 10:1:3.

[0068] Furthermore, the sintering temperature is 700° C. to 900° C., and the sintering time is 1 hour to 3 hours. Preferably, in step S22 , the sintering temperature is 800° C., and the sintering time is 2 hours.

[0069] like Figure 1 and Figure 4 As shown, in an implementable specific example, in step S3, the specific steps of obtaining BaTiO3 ceramics include:

[0070] S31: mixing the doped BaTiO3 material and the additive in a mass ratio of (97-99): (3-1);

[0071] S32: Using deionized water as a solvent and ZrO2 balls as a ball milling medium, the mixed material in step S31 is ball milled in a nylon jar, with the ratio of mixed material: ZrO2 balls: deionized water being 1:4:1.5;

[0072] S33: adding 2% by mass of SiO2 sol to the ball milled material in step S32 for granulation;

[0073] S34: dry pressing under a pressure of 20 MPa, and keeping the green body at 600°C for 2 hours for debinding;

[0074] S35: Sintering the debinded green body in air to obtain BaTiO3 ceramics.

[0075] Furthermore, in step S31, the doped BaTiO3 base material and the auxiliary agent are mixed in a mass ratio of 98:2.

[0076] Furthermore, in step S35, the sintering temperature is 1200° C. to 1250° C., and the sintering time is 1.5 hours to 2.5 hours. Preferably, in step S35, the sintering temperature is 1250° C., and the sintering time is 2 hours.

[0077] like Figure 1 and Figure 5 As shown, the preparation method of the high dielectric ceramic capacitor further includes:

[0078] S4: forming an electrode layer on the surface of BaTiO3 ceramics using screen printing technology;

[0079] S5: forming solder pins on the electrode layer;

[0080] S6: Encapsulating the BaTiO3 ceramic to form a ceramic capacitor.

[0081] Specifically, after polishing and cleaning the BaTiO3 ceramic, silver electrode slurry is evenly coated on both sides of the ceramic and sintered at 600°C for 20 minutes. A soldering pin is formed on the electrode layer. High-temperature heating causes the solder to wet and diffuse through the welded parts, forming a non-peelable conductive alloy layer that securely connects the welded parts. Soldering involves three main steps: solder wetting, diffusion, and bonding. Finally, the BaTiO3 ceramic is encapsulated to form the desired high-dielectric ceramic capacitor.

[0082] This embodiment further provides a high dielectric ceramic capacitor, which is prepared by any of the above-mentioned methods for preparing a high dielectric ceramic capacitor.

[0083] The high-dielectric ceramic capacitor of this embodiment can store more charge due to its extremely high dielectric constant, thereby improving capacitance performance. This means that at the same capacitance value, the high-dielectric ceramic capacitor of this embodiment can be made smaller, which is conducive to the miniaturization of the capacitor; the significant temperature stability and low loss enable the ceramic capacitor to maintain stable electrical performance under extreme temperature conditions, providing more reliable protection for electronic devices based on it; the high-dielectric ceramic capacitor of this embodiment does not contain components that are harmful to the human body and the environment, such as volatile or heavy metal components such as lead and cadmium during the sintering process, ensuring the green and environmentally friendly characteristics of the material, and greatly reducing production costs, achieving the dual advantages of economic benefits and environmental friendliness.

[0084] Example 1

[0085] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The specific preparation method includes:

[0086] Step S1: BaCO3 and TiO2 powder materials are mixed in a molar ratio of 1:1; using deionized water as a solvent and ZrO2 balls as ball milling media, the powder materials are ball milled in a nylon jar, the ratio of powder material: ZrO2 balls: deionized water is 1:4:1, and the ball milling time is 6 hours; the ball-milled mixture is placed in an oven for drying and passed through a 50-mesh sieve; the sieved mixture is sintered in air at a sintering temperature of 1100°C and a sintering time of 1 hour to obtain a BaTiO3 base material.

[0087] Step S2: BaCO3, B2O3 and MnO are mixed in a mass ratio of 10:0.5:2; the mixed material is sintered in air at a sintering temperature of 700°C and a sintering time of 1 hour to obtain an additive.

[0088] Step S3: Mix the BaTiO3 base material and the additive in a mass ratio of 99:1; use deionized water as a solvent and ZrO2 balls as ball milling media to ball mill the mixed material in a nylon jar, and the ratio of mixed material: ZrO2 balls: deionized water is 1:4:1.5; add 2% by mass fraction of SiO2 sol to the ball mill material for granulation; dry press under a pressure of 20 MPa, and keep the green body at 600°C for 2 hours for debinding; sinter the green body after debinding in air at a sintering temperature of 1200°C and a sintering time of 1.5 hours to obtain BaTiO3 ceramics.

[0089] Step S4: forming an electrode layer on the surface of the BaTiO3 ceramic using screen printing technology.

[0090] Step S5: forming solder pins on the electrode layer.

[0091] Step S6: encapsulating the BaTiO 3 ceramic to form a BaTiO 3 -based ceramic capacitor.

[0092] Example 2

[0093] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The specific preparation method includes:

[0094] Step S1: BaCO3 and TiO2 powder materials are mixed in a molar ratio of 1:1, and 1% Nb2O5 is added to the powder materials; deionized water is used as a solvent, ZrO2 balls are used as ball milling media, and the powder materials are ball milled in a nylon jar, the ratio of powder material: ZrO2 balls: deionized water is 1:4:1, and the ball milling time is 6 hours; the ball-milled mixture is placed in an oven for drying and passed through a 50-mesh sieve; the sieved mixture is sintered in air at a sintering temperature of 1100°C and a sintering time of 1 hour to obtain a BaTiO3 base material doped with Nb.

[0095] Step S2: BaCO3, B2O3 and MnO are mixed in a mass ratio of 10:0.5:2; the mixed material is sintered in air at a sintering temperature of 700°C and a sintering time of 1 hour to obtain an additive.

[0096] Step S3: Mix the Nb-doped BaTiO3 base material and the additive in a mass ratio of 99:1; use deionized water as a solvent and ZrO2 balls as ball milling media to ball mill the mixed material in a nylon jar, and the ratio of mixed material: ZrO2 balls: deionized water is 1:4:1.5; add 2% by mass fraction of SiO2 sol to the ball mill material for granulation; dry press under a pressure of 20 MPa, and keep the green body at 600°C for 2 hours for debinding; sinter the debinded green body in air at a sintering temperature of 1200°C and a sintering time of 1.5 hours to obtain BaTiO3 ceramics.

[0097] Step S4: forming an electrode layer on the surface of the BaTiO3 ceramic using screen printing technology.

[0098] Step S5: forming solder pins on the electrode layer.

[0099] Step S6: encapsulating the BaTiO 3 ceramic to form a BaTiO 3 -based ceramic capacitor.

[0100] Example 3

[0101] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 1, except that in step S1, 2% Nb2O5 is added to the powder material. The doping amount of the BaTiO3 base material in this embodiment is as described in Table 1 below.

[0102] Example 4

[0103] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 1, except that in step S1, 3% Nb2O5 is added to the powder material. The doping amount of the BaTiO3 base material in this embodiment is as described in Table 1 below.

[0104] Example 5

[0105] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 1, except that in step S1, 2% Nb2O5 and 0.1% Gd2O3 are added to the powder material. The doping amount of the BaTiO3 base material in this embodiment is described in Table 1 below.

[0106] Example 6

[0107] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 1, except that in step S1, 2% Nb2O5 and 0.15% Gd2O3 are added to the powder material. The doping amount of the BaTiO3 base material in this embodiment is described in Table 1 below.

[0108] Example 7

[0109] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 1, except that in step S1, 2% Nb2O5 and 0.2% Gd2O3 are added to the powder material. The doping amount of the BaTiO3 base material in this embodiment is as described in Table 1 below.

[0110] Table 1

[0111]

[0112] Example 8

[0113] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 6, except that in step S1, the sintering temperature is 1200° C. and the sintering time is 1 hour. The sintering parameters in this embodiment are described in Table 2 below.

[0114] Example 9

[0115] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 6, except that in step S1, the sintering temperature is 1300° C. and the sintering time is 1 hour. The sintering parameters in this embodiment are described in Table 2 below.

[0116] Example 10

[0117] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 6, except that in step S1, the sintering temperature is 1200° C. and the sintering time is 2 hours. The sintering parameters in this embodiment are described in Table 2 below.

[0118] Example 11

[0119] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 6, except that in step S1, the sintering temperature is 1200° C. and the sintering time is 3 hours. The sintering parameters in this embodiment are described in Table 2 below.

[0120] Table 2

[0121]

[0122] Doping with Nb2O5 and / or Gd2O3 can improve the dielectric constant of BaTiO3 ceramic capacitors to varying degrees. Doping with Nb2O5 can make the Nb-rich non-ferroelectric phase Ba(Ti x Nb (1-x))O3 increases, thereby affecting the dielectric constant of the ceramic system and improving temperature stability; the doping of Gd2O3 improves the dielectric constant of the ceramic system by replacing the rare earth ions in the perovskite; the composite doping of Nb2O5 and Gd2O3 can not only improve the dielectric constant of BaTiO3 ceramic capacitors, but also help to reduce the sintering temperature of ceramic capacitors.

[0123] Example 12

[0124] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 10, except that in step S2, the mixing mass ratio of BaCO3, B2O3 and MnO is 10:1:2. The mixing mass ratio of the additives in this embodiment is as described in Table 3 below.

[0125] Example 13

[0126] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 10, except that in step S2, the mixing mass ratio of BaCO3, B2O3 and MnO is 10:1.5:2. The mixing mass ratio of the additives in this embodiment is as described in Table 3 below.

[0127] Example 14

[0128] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 10, except that in step S2, the mixing mass ratio of BaCO3, B2O3 and MnO is 10:2:2. The mixing mass ratio of the additives in this embodiment is as described in Table 3 below.

[0129] Example 15

[0130] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 10, except that in step S2, the mixing mass ratio of BaCO3, B2O3 and MnO is 10:1:3. The mixing mass ratio of the additives in this embodiment is as described in Table 3 below.

[0131] Example 16

[0132] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 10, except that in step S2, the mixing mass ratio of BaCO3, B2O3 and MnO is 10:1:4. The mixing mass ratio of the additives in this embodiment is as described in Table 3 below.

[0133] Table 3

[0134]

[0135] Example 17

[0136] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 15, except that in step S2, the sintering temperature is 800° C. and the sintering time is 1 hour. The sintering parameters in this embodiment are described in Table 4 below.

[0137] Example 18

[0138] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 15, except that in step S2, the sintering temperature is 900° C. and the sintering time is 1 hour. The sintering parameters in this embodiment are described in Table 4 below.

[0139] Example 19

[0140] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 15, except that in step S2, the sintering temperature is 800° C. and the sintering time is 2 hours. The sintering parameters in this embodiment are described in Table 4 below.

[0141] Example 20

[0142] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 15, except that in step S2, the sintering temperature is 800° C. and the sintering time is 3 hours. The sintering parameters in this embodiment are described in Table 4 below.

[0143] Table 4

[0144]

[0145] BaCO₃ is one of the main raw materials for preparing BaTiO₃ ceramics. It decomposes at high temperatures to produce BaO, an essential component for forming the BaTiO₃ structure and preventing the introduction of other impurities into BaTiO₃ ceramics. The addition of B₂O₃ can lower the sintering temperature of BaTiO₃ ceramics, improving the density and dielectric properties of the ceramics. The addition of B₂O₃ can also reduce the initial precipitation temperature of the slag, change the primary crystalline phase of the slag from melilite to spinel, and improve the slag fluidity. The addition of MnO can improve the dielectric-temperature characteristics of BaTiO₃-based ceramics. Although this may reduce the dielectric constant to a certain extent, it can broaden the Curie peak and effectively inhibit secondary recrystallization of BaTiO₃. Composite additives can lower the sintering temperature, improve dielectric properties, and broaden the Curie peak. They also help control grain growth and improve the temperature stability of the ceramics.

[0146] Example 21

[0147] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 19, except that in step S3, the doped BaTiO3 base material and the additive are mixed in a mass ratio of 98:2. The mass ratio of the doped BaTiO3 base material and the additive in this embodiment is described in Table 6 below.

[0148] Example 21

[0149] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 19, except that in step S3, the doped BaTiO3 base material and the additive are mixed in a mass ratio of 97:3. The mass ratio of the doped BaTiO3 base material and the additive in this embodiment is described in Table 6 below.

[0150] Table 6

[0151]

[0152] Example 23

[0153] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 21, except that in step S3, the sintering temperature is 1250° C. and the sintering time is 1.5 h. The sintering parameters in this embodiment are described in Table 7 below.

[0154] Example 24

[0155] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 21, except that in step S3, the sintering temperature is 1300° C. and the sintering time is 1.5 h. The sintering parameters in this embodiment are described in Table 7 below.

[0156] Example 25

[0157] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 21, except that in step S3, the sintering temperature is 1250° C. and the sintering time is 2 hours. The sintering parameters in this embodiment are described in Table 7 below.

[0158] Example 26

[0159] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Example 21, except that in step S3, the sintering temperature is 1250° C. and the sintering time is 2.5 h. The sintering parameters in this embodiment are described in Table 7 below.

[0160] Table 7

[0161] Example No. Sintering temperature (℃) Sintering time (h) Dielectric constant Loss value (%) Capacitance temperature change rate (%) 21 1200 1.5 2087 1.42 9.9 23 1250 1.5 2196 1.45 9.2 24 1300 1.5 2160 1.47 9.5 25 1250 2 2200 1.36 8.9 26 1250 2.5 2178 1.37 8.9

[0162] As shown in Table 7, the BaTiO3 high dielectric ceramic capacitors prepared in Examples 21 to 25 have a dielectric constant of 2000 to 2200, a loss value <1.5%, and a capacitance temperature change rate |Δε| / ε 25 ≤10%, and the insulation resistivity is around 500GΩ at 1.0kHz, which meets the X8P standard of the electronics industry standard.

[0163] In summary, the present invention provides a high dielectric ceramic capacitor and a preparation method thereof. The preparation method of the high dielectric ceramic capacitor at least includes: S1: mixing BaCO3 and TiO2 powder materials, and adding Nb2O5 and Gd2O3 to obtain a BaTiO3 base material doped with Nb and Gd; S2: mixing BaCO3, B2O3 and MnO to obtain an additive; S3: mixing the doped BaTiO3 base material with the additive to obtain BaTiO3 ceramic. The high-dielectric ceramic capacitor of the present invention can store more charge due to its extremely high dielectric constant, thereby improving capacitance performance. This means that at the same capacitance value, the high-dielectric ceramic capacitor of the present invention can be made smaller, which is conducive to the miniaturization of the capacitor; the significant temperature stability and low loss enable the ceramic capacitor to maintain stable electrical performance under extreme temperature conditions, providing more reliable protection for electronic devices based on it; the high-dielectric ceramic capacitor of the present invention does not contain components harmful to the human body and the environment, such as volatile or heavy metal components such as lead and cadmium during the sintering process, ensuring the green and environmentally friendly characteristics of the material, and greatly reducing production costs, achieving the dual advantages of economic benefits and environmental friendliness. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial utilization value.

[0164] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for preparing a high dielectric ceramic capacitor, characterized in that: The method for preparing the high dielectric ceramic capacitor at least comprises: S1: BaCO3 and TiO2 powder materials are mixed, and Nb2O5 and Gd2O3 are added, and sintered to obtain a BaTiO3 base material doped with Nb and Gd. The specific steps of preparing the BaTiO3 base material doped with Nb and Gd include: S11: mixing BaCO3 and TiO2 powder materials in a molar ratio of 1:1; S12: Add 2%~3% Nb2O5 and 0.1%~0.15% Gd2O3 to the powder material; S13: Using deionized water as solvent and ZrO2 balls as ball milling media, the powder material is ball milled in a nylon jar. The ratio of powder material: ZrO2 balls: deionized water is 1:4:1, and the ball milling time is 6 hours. S14: The ball-milled mixture is placed in an oven for drying and passed through a 50-mesh sieve; S15: sintering the sieved mixture in air to obtain a BaTiO3 base material doped with Nb and Gd, wherein the sintering temperature is 1100° C. to 1300° C. and the sintering time is 1 hour to 3 hours; S2: BaCO3, B2O3 and MnO are mixed and sintered to obtain an additive. The specific steps of obtaining the additive include: S21: BaCO3, B2O3 and MnO are mixed in a mass ratio of 10: (0.5~2): (2~4); S22: sintering the mixed material in step S21 in air to obtain an additive, wherein the sintering temperature is 700° C. to 900° C. and the sintering time is 1 hour to 3 hours; S3: mixing the doped BaTiO3 base material with the auxiliary agent, and sequentially performing debinding and sintering to obtain BaTiO3 ceramics. The specific steps of obtaining the BaTiO3 ceramics include: S31: mixing the doped BaTiO3 base material and the auxiliary agent in a mass ratio of (97-99): (3-1); S32: Using deionized water as a solvent and ZrO2 balls as a ball milling medium, the mixed material in step S31 is ball milled in a nylon jar, with the ratio of mixed material: ZrO2 balls: deionized water being 1:4:1.5; S33: adding 2% by mass of SiO2 sol to the ball milled material in step S32 for granulation; S34: dry pressing under a pressure of 20 MPa, and keeping the green body at 600°C for 2 hours for debinding; S35: sintering the debinded green body in air to obtain the BaTiO3 ceramic, wherein the sintering temperature is 1200° C. to 1300° C. and the sintering time is 1.5 h to 2.5 h.

2. The method for preparing a high dielectric ceramic capacitor according to claim 1, wherein: In step S21, BaCO3, B2O3 and MnO are mixed in a mass ratio of 10:1:

3.

3. The method for preparing a high dielectric ceramic capacitor according to claim 1, wherein: In step S31, the doped BaTiO3 base material and the auxiliary agent are mixed in a mass ratio of 98:

2.

4. The method for preparing a high dielectric ceramic capacitor according to claim 1, wherein: The method for preparing the high dielectric ceramic capacitor further includes: S4: forming an electrode layer on the surface of the BaTiO3 ceramic using a screen printing technique; S5: forming solder pins on the electrode layer; S6: Encapsulating the BaTiO3 ceramic to form a ceramic capacitor.

5. A high dielectric ceramic capacitor, characterized in that: The high dielectric ceramic capacitor is prepared by the method for preparing a high dielectric ceramic capacitor according to any one of claims 1 to 4.

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