High dielectric ceramic capacitor and preparation method thereof

Abstract

The invention provides a high dielectric ceramic capacitor and a preparation method thereof, and the preparation method comprises the steps: 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, BaCO3, B2O3 and MnO are mixed, sintering is carried out, and an auxiliary agent is obtained; and S3, mixing the doped BaTiO3 base material with an auxiliary agent, and sequentially carrying out glue discharging and sintering to obtain the BaTiO3 ceramic. According to the high-dielectric ceramic capacitor, more charges can be stored due to the extremely high dielectric constant of the high-dielectric ceramic capacitor, so that the capacitance performance is improved, and the miniaturization of the capacitor is facilitated; the ceramic capacitor has remarkable temperature stability and lower loss, so that the ceramic capacitor can still keep stable electrical performance under an extreme temperature condition, and more reliable guarantee is provided for electronic equipment based on the ceramic capacitor; the high-dielectric ceramic capacitor does not contain components harmful to human bodies and the environment in the sintering process, is green and environment-friendly, is low in cost, and achieves the dual advantages of economic benefits and environment 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] As an important component of electronic components, ceramic capacitors are a common passive electrical appliance widely used in various electronic devices. As electronic devices develop towards miniaturization and lightweight, the requirements for miniaturization of electronic components are getting higher and higher, which has greatly increased the demand for high-dielectric ceramic capacitors. While pursuing high dielectric constants to achieve small volume and large capacity, technicians also use appropriate amounts of doping to achieve ideal electrical performance. Commonly used standards for measuring the temperature stability of ceramic capacitors are X7R, X7P, and X8R, X8P. X7R and X7P refer to the capacitance change rate within 15% and 10% respectively within -55℃~125℃, and X8R and X8P refer to the capacitance change rate within 15% and 10% respectively within -55℃~150℃. X8R ceramic capacitors have better capacity stability and higher dielectric constants. When temperature, voltage and time change, the performance changes are not significant, that is, high dielectric constant and low change rate. Among them, "X" means the temperature is "-55℃", "8" means the temperature is "150℃", and "R" means that within the temperature range of -55℃ to 150℃, the difference between the capacitance at room temperature (25℃) and the capacitance at -55℃ and 150℃ divided by the capacitance at 25℃ should be ≤15%, that is, the capacitance-temperature change rate should not be greater than 15%. The temperature stability of X8P ceramic capacitors is better, requiring the capacitance-temperature change rate to be no greater than 10%.

[0003] At present, the research on temperature stability of high dielectric constant ceramic capacitors is mainly based on the X7R standard, while the existing research on some high temperature stability materials higher than the X7R standard is mainly focused on low dielectric constant materials. However, with the development of aerospace, oil drilling and other fields in recent years, the X7R standard dielectric ceramics currently widely used in electronic communication equipment, sensors and other aspects can no longer meet the use requirements of these electronic devices with high temperature stability requirements; at the same time, these fields require capacitors with small volume and large capacity, which in turn requires high dielectric constant materials.

[0004] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present application.

[0005] In view of the above, there is an urgent need to provide a high dielectric ceramic capacitor and a preparation method thereof, which can meet the X8P requirements of the electronic 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, an object of the present invention is to provide a high dielectric ceramic capacitor with high temperature stability, high dielectric constant and low loss and a preparation method thereof, so as to solve the problem of poor temperature stability in the prior art.

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

[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 them 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% Nb2O5 and 0.1% to 0.2% 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: placing the ball-milled mixture in an oven for drying and passing through a 50-mesh sieve;

[0016] S15: Sintering the screened 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 1h to 3h.

[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 1h to 3h.

[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 solvent and ZrO2 balls as ball milling media, the mixed material in step S31 is ball milled in a nylon jar, wherein the ratio of the mixed material: ZrO2 balls: deionized water is 1:4:1.5;

[0028] S33: adding 2% by mass of SiO2 sol to the ball mill 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 h for debinding;

[0030] S35: Sintering the green body after debinding 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 by screen printing technology;

[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, which fully meets the X8P requirements of the electronic industry standard. High dielectric ceramic capacitors can store more charge due to their extremely high dielectric constant, thereby improving capacitance performance, which 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; significant temperature stability and low loss can 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, which ensures the green and environmentally friendly characteristics of the material, and greatly reduces production costs, achieving the dual advantages of economic benefits and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram showing the process of the method for preparing a high dielectric ceramic capacitor of 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 of 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 of the present invention.

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

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

[0045] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0046] 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, which should not limit the scope of protection of the present invention.

[0047] For ease of description, spatial relational terms such as "under", "below", "below", "below", "above", "on", etc. 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 spatial relational terms are intended to include other directions of the device in use or operation in addition to the directions depicted in the drawings. In addition, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there may be one or more intervening layers. As used herein, "between..." means including the end point values.

[0048] In the context of the present application, a structure in which a first feature is described as being "above" a second feature may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are 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 illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being 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 complicated.

[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 a BaTiO3 base material doped with Nb and Gd;

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

[0053] S3: mixing the doped BaTiO3 base material with the additive, and sequentially performing debinding and sintering 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 a specific example that can be implemented, in step S1, the specific steps of preparing the 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: placing the ball-milled mixture in an oven for drying and passing through a 50-mesh sieve;

[0060] S15: Sintering the screened 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] Further, 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] Further, 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 a specific example that can be implemented, 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 solvent and ZrO2 balls as ball milling media, the mixed material in step S31 is ball milled in a nylon jar, wherein the ratio of the mixed material: ZrO2 balls: deionized water is 1:4:1.5;

[0072] S33: adding 2 mass% SiO2 sol to the ball mill 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 h for debinding;

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

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

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

[0077] like Figure 1 and Figure 5 As shown, the method for preparing a high dielectric ceramic capacitor also includes:

[0078] S4: forming an electrode layer on the surface of BaTiO3 ceramic by 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 BaTiO3 ceramic, and sintered at 600°C for 20 minutes; solder pins are formed on the electrode layer, and the solder is heated at high temperature to infiltrate and diffuse on the weldment to form an unpeelable conductive alloy layer, thereby firmly welding the weldment together. Soldering includes the following three main processes: solder infiltration, diffusion, and bonding layer of the weldment; finally, the BaTiO3 ceramic is encapsulated to form the required high dielectric ceramic capacitor.

[0082] This embodiment 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.

[0083] The high dielectric ceramic capacitor of this embodiment can store more charge due to its extremely high dielectric constant, thereby improving the capacitance performance, which 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 can 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 during the sintering process, such as volatile or heavy metal components such as lead and cadmium, which ensures the green and environmentally friendly characteristics of the material, and greatly reduces the production cost, 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, and the specific preparation method includes:

[0086] Step S1: BaCO3 and TiO2 powder materials are mixed in a molar ratio of 1:1; deionized water is used as a solvent and ZrO2 balls are used as ball milling media to ball mill the powder materials 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 auxiliary agent in a mass ratio of 99:1; use deionized water as 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 for granulation; dry press under a pressure of 20MPa, and keep the green body at 600℃ for 2h for debinding; sinter the debinded green body in air at a sintering temperature of 1200℃ and a sintering time of 1.5h to obtain BaTiO3 ceramics.

[0089] Step S4: forming an electrode layer on the surface of BaTiO3 ceramic by 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, and 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 material; deionized water is used as a solvent, and ZrO2 balls are used as ball milling media, and 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; 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 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 for granulation; dry press under a pressure of 20MPa, and keep the green body at 600℃ for 2h for debinding; sinter the debinded green body in air at a sintering temperature of 1200℃ and a sintering time of 1.5h to obtain BaTiO3 ceramics.

[0097] Step S4: forming an electrode layer on the surface of BaTiO3 ceramic by 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 Embodiment 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 Embodiment 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, and its operation is basically the same as that of Example 1, except that in step S1, 2% Nb2O5 is added to the powder material, and 0.1% Gd2O3 is also added to the powder material. The doping amount of the BaTiO3 base material in this embodiment is as described in Table 1 below.

[0106] Example 6

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

[0108] Example 7

[0109] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its operation is basically the same as that of Example 1, except that in step S1, 2% Nb2O5 is added to the powder material, and 0.2% Gd2O3 is also added to the powder material. The amount of doping material 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 Embodiment 6, except that in step S1, the sintering temperature is 1200° C. and the sintering time is 1 h. 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 Embodiment 6, except that in step S1, the sintering temperature is 1300° C. and the sintering time is 1 h. 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 Embodiment 6, except that in step S1, the sintering temperature is 1200° C. and the sintering time is 2 h. The sintering parameters in this embodiment are described in Table 2 below.

[0118] Embodiment 11

[0119] This embodiment provides a method for preparing a high dielectric ceramic capacitor. The operation is basically the same as that of Embodiment 6, except that in step S1, the sintering temperature is 1200° C. and the sintering time is 3 h. 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. Nb2O5 doping 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 the 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, and its 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, and its 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] Embodiment 14

[0128] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its operation is basically the same as that of Embodiment 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] Embodiment 15

[0130] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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 described in Table 3 below.

[0131] Example 16

[0132] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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] Embodiment 17

[0136] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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] Embodiment 18

[0138] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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] Embodiment 19

[0140] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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 h. The sintering parameters in this embodiment are described in Table 4 below.

[0141] Embodiment 20

[0142] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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 temperature to produce BaO, which is a necessary component for forming the BaTiO3 structure and also avoids introducing other impurities into BaTiO3 ceramics. The addition of B2O3 can reduce the sintering temperature of BaTiO3 ceramics and improve the density and dielectric properties of ceramics. The addition of B2O3 can reduce the initial precipitation temperature of slag, change the main crystal phase of slag from melilite to spinel, and improve the fluidity of slag. The addition of MnO can improve the dielectric temperature characteristics of BaTiO3-based ceramics. Although it will reduce the dielectric constant to a certain extent, it can broaden the Curie peak and has a good inhibitory effect on the secondary recrystallization of BaTiO3. Composite additives can reduce the sintering temperature, improve dielectric properties and broaden the Curie peak. It also helps to control grain growth and improve the temperature stability of ceramics.

[0146] Embodiment 21

[0147] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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] Embodiment 21

[0149] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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] Embodiment 23

[0153] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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] Embodiment 24

[0155] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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] Embodiment 25

[0157] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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 h. The sintering parameters in this embodiment are described in Table 7 below.

[0158] Embodiment 26

[0159] This embodiment provides a method for preparing a high dielectric ceramic capacitor, and its 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 1.0kHz 500GΩ, 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 ceramics. The high dielectric ceramic capacitor of the present invention can store more charge due to its extremely high dielectric constant, thereby improving the capacitance performance, which 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 can 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 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 the production cost, 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 a 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 familiar with 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 a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still 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; S2: Mix BaCO3, B2O3 and MnO and sinter them to obtain an additive; S3: mixing the doped BaTiO3 base material with the auxiliary agent, and sequentially performing debinding and sintering to obtain BaTiO3 ceramics.

2. The method for preparing a high dielectric ceramic capacitor according to claim 1, characterized in that: In step S1, 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: adding 1% to 3% Nb2O5 and 0.1% to 0.2% 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: placing the ball-milled mixture in an oven for drying and passing through a 50-mesh sieve; S15: Sintering the screened mixed material in air to obtain the BaTiO3 base material doped with Nb and Gd.

3. The method for preparing a high dielectric ceramic capacitor according to claim 2, characterized in that: In step S12, 2% Nb2O5 is added to the powder material.

4. The method for preparing a high dielectric ceramic capacitor according to claim 2, characterized in that: In step S12, 0.15% of Gd2O3 is added to the powder material.

5. The method for preparing a high dielectric ceramic capacitor according to claim 2, characterized in that: In step S15, the sintering temperature is 1100°C to 1300°C, and the sintering time is 1h to 3h.

6. The method for preparing a high dielectric ceramic capacitor according to claim 1, characterized in that: In step S2, the specific steps of obtaining the auxiliary agent 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.

7. The method for preparing a high dielectric ceramic capacitor according to claim 6, characterized in that: In step S21, BaCO3, B2O3 and MnO are mixed in a mass ratio of 10:1:

3.

8. The method for preparing a high dielectric ceramic capacitor according to claim 6, characterized in that: In step S22, the sintering temperature is 700°C to 900°C, and the sintering time is 1 hour to 3 hours.

9. The method for preparing a high dielectric ceramic capacitor according to claim 1, characterized in that: In step S3, the specific steps of obtaining the BaTiO3 ceramic 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 solvent and ZrO2 balls as ball milling media, the mixed material in step S31 is ball milled in a nylon jar, wherein the ratio of the mixed material: ZrO2 balls: deionized water is 1:4:1.5; S33: adding 2% by mass of SiO2 sol to the ball mill in step S32 for granulation; S34: dry pressing under a pressure of 20 MPa, and keeping the green body at 600° C. for 2 h for debinding; S35: Sintering the green body after debinding in air to obtain the BaTiO3 ceramic.

10. The method for preparing a high dielectric ceramic capacitor according to claim 9, characterized in that: In step S31, the doped BaTiO3 base material and the auxiliary agent are mixed in a mass ratio of 98:

2.

11. The method for preparing a high dielectric ceramic capacitor according to claim 9, characterized in that: In step S35, the sintering temperature is 1200°C to 1300°C, and the sintering time is 1.5h to 2.5h.

12. The method for preparing a high dielectric ceramic capacitor according to claim 1, characterized in that: The method for preparing the high dielectric ceramic capacitor further comprises: S4: forming an electrode layer on the surface of the BaTiO3 ceramic by screen printing technology; S5: forming solder pins on the electrode layer; S6: Encapsulating the BaTiO3 ceramic to form a ceramic capacitor.

13. 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 12.

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