Temperature characteristic controllable multilayer ceramic dielectric capacitor and preparation method thereof

Abstract

The invention relates to a temperature characteristic controllable multilayer ceramic dielectric capacitor and a preparation method thereof, the multilayer ceramic dielectric capacitor is formed by a dielectric layer A and a dielectric layer B through mutual staggered superposition and firing, the dielectric layer A is composed of barium titanate, magnesium oxide, manganous-manganic oxide, vanadyl acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate and zirconium oxide, and the dielectric layer B is composed of barium titanate, magnesium oxide, manganous-manganic oxide, vanadyl acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate and zirconium oxide; the dielectric layer B is composed of barium titanate, magnesium oxide, manganous-manganic oxide, vanadyl acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide and nickel oxide; the multilayer ceramic dielectric capacitor is formed by the dielectric layers A and the dielectric layers B in a staggered and stacked mode through firing, the combination of the double dielectric layers is different from a traditional single dielectric layer, and the capacitor has the advantages of being high in dielectric constant and high in temperature stability at the same time.

Description

Technical Field

[0001] The invention belongs to the field of ceramic capacitor preparation, and in particular relates to a temperature characteristic controllable multilayer ceramic capacitor and a preparation method thereof. Background Art

[0002] With the rapid development of electronic information technology, multilayer ceramic capacitors (MLCCs) are becoming increasingly important as an indispensable passive component in electronic devices. With its excellent electrical performance, MLCCs play a vital role in many high-end technology fields, including but not limited to consumer electronics, automotive electronics, 5G communications, aerospace, and military industries. With the lightweight and functional integration of mobile devices, the MLCC industry is moving towards smaller size, higher capacitance density, better reliability, and more stable temperature characteristics. This trend not only brings huge market potential to the MLCC industry, but also poses higher challenges to the performance of dielectric materials.

[0003] As an economical and efficient ferroelectric material, barium titanate has been widely used in MLCC due to its high dielectric constant. However, pure barium titanate has a low Curie temperature and a large temperature coefficient and dielectric loss, which limits its use in high-performance applications. Therefore, improving the performance of barium titanate by doping modification has become the key to the development of MLCC technology.

[0004] In the pursuit of high capacity and miniaturization of MLCC, the ultra-thinning of the dielectric layer is a technical challenge. The reduction in the thickness of the dielectric layer requires that the particle size of barium titanate in the casting slurry be finer to ensure a sufficient number of grains and grain boundaries to meet the requirements of the capacitor for insulation resistance and safety. However, excessive refinement of the particle size may destroy the structure of barium titanate, increase grain defects, and affect its dielectric properties and temperature stability. At the same time, although barium titanate with a larger particle size can maintain a higher dielectric constant, its grain size after sintering is larger, which limits the miniaturization development of MLCC. In order to overcome these limitations and further improve the comprehensive electrical performance, it is a problem to be solved by the present invention to ensure that the capacitor has good temperature characteristics, high safety, high dielectric constant, and is suitable for the application of miniaturized MLCC. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a multilayer ceramic capacitor with controllable temperature characteristics and a preparation method thereof.

[0006] The present invention adopts the following technical solution:

[0007] A temperature-controlled multilayer ceramic capacitor is formed by stacking and firing dielectric layers A and B in a staggered manner, wherein:

[0008] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadyl acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100: 0.1-1.5: 0.07-0.13: 0.05-0.1: 0.2-1: 0.5-2: 0.2-1: 0.1-0.5: 0.3-0.6;

[0009] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, and nickel oxide in a molar ratio of 100: 0.1-0.5: 0.03-0.07: 0.1-0.5: 0.2-1: 0.5-2: 0.2-1: 0.1-0.5: 0.3-0.6: 0.2-0.8.

[0010] Furthermore, the rare earth oxide A and the rare earth oxide C include at least one of Eu, Gd, Tb, Dy, and Ho oxides.

[0011] Furthermore, the rare earth oxide B and the rare earth oxide D include at least one of Sc, Y, Er, Tm, Yb, and Lu oxides.

[0012] Furthermore, the thickness of the dielectric layer A is 1-6 um, and the thickness of the dielectric layer B is 1-6 um.

[0013] Furthermore, the particle size of the barium titanate is 200-300 nm.

[0014] Furthermore, the average particle size of the ceramic powder of the dielectric layer A and the dielectric layer B is less than 200 nm.

[0015] A method for preparing a temperature-controlled multilayer ceramic capacitor comprises the following steps:

[0016] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it with alcohol as the medium for 2-10 hours, and grind it with the bead mill until the particle size is less than 200nm to obtain the dopant slurry of dielectric layer A;

[0017] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 1-8 hours, grinding and dispersing it fully; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 2-6 hours, ball milling for 2-18 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:2-12:8-20 respectively;

[0018] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 1-6 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0019] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 2-10 hours, and grind it with the bead mill until the particle size is less than 200nm to obtain the dopant slurry of dielectric layer B;

[0020] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 1-8 hours, grinding and dispersing it fully; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 2-6 hours, ball milling for 2-18 hours, filtering, defoaming, and obtaining a casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:2-12:8-20 respectively;

[0021] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 1-6 μm, and then printing the nickel electrode slurry on the dielectric layer to form a dielectric layer B;

[0022] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0023] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0024] Furthermore, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 210-450° C. for degreasing for 20-86 hours.

[0025] Further, in step eight, the sintering process is as follows: the sintering environment is selected as N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 35-80:1, distilled water at 25-80℃ is humidified and passed into the furnace, and kept at 1180-1310℃ for 1-6h at a rate of 2-30℃ / min, then cooled to 800-1100℃ for oxygen recovery, with an oxygen content of 5-100ppm, kept warm for 2-10h, and then cooled to room temperature to obtain a porcelain body.

[0026] Furthermore, in step eight, the sintering is performed under nitrogen protection.

[0027] It can be seen from the above description of the present invention that, compared with the prior art, the present invention has the following beneficial effects:

[0028] First, the multilayer ceramic capacitor defined in the present application is formed by staggered stacking and firing of dielectric layer A and dielectric layer B. The double dielectric layer combination is different from the traditional single dielectric layer, so that the capacitor has the advantages of high dielectric constant and high temperature stability at the same time; by limiting the ratio of the two dielectric layer materials, two materials with different temperature characteristics are selected, one material is negative at high temperature, and the other is positive at high temperature. The combination of the two dielectrics and the doping of the two dielectrics can achieve combined regulation of the temperature characteristics, thereby obtaining the stability of the MLCC in a wide temperature range. At the same time, the combination of the two dielectric layers can balance the characteristics of the two dielectric materials, such as high dielectric constant and low loss, so as to achieve better controllability of the temperature characteristics without sacrificing the performance of the capacitor;

[0029] Second, the combination of dual dielectric layers affects the microstructure of the organization, achieving low loss and high insulation resistance; dual dielectrics affect grain growth, and the internal structure grain growth is restricted. Small grains can reduce defects at the grain boundaries, thereby reducing dielectric loss and improving insulation performance; at the same time, dual dielectric doping elements have similar components and similar sintering shrinkage characteristics, which is conducive to co-firing. By precisely controlling sintering, it is ensured that the two dielectric materials are evenly distributed and combined on a microscopic scale, thereby improving the dielectric constant and temperature stability of the capacitor;

[0030] Third, the different types of rare earth doping in the dual dielectric layers, in synergy with elements such as Mg and V, enable the dielectric layers A / B to obtain high K values ​​and temperature characteristics with different characteristics; the addition of rare earth elements helps to control grain growth and avoid abnormal grain growth, thereby maintaining the uniformity and consistency of the material, and obtaining a ceramic material with high dielectric constant, high insulation resistance and high reliability; among them, rare earth oxides A, B, C and D represent two groups of rare earth elements with different ionic radii, and when they are jointly doped, they can accurately and selectively replace specific sites in the barium titanate lattice, significantly improving the reliability of its application; in addition, magnesium oxide and vanadium acetylacetonate are used in combination with rare earth oxides A, B, C and D, and through their synergistic effect, the temperature characteristic curve of the capacitor is finely controlled to ensure performance stability at different temperatures;

[0031] Fourth, the doping of Ni element enables the dielectric layer B to obtain positive temperature characteristics at high temperatures. The introduction of NiO as an effective dopant optimizes the microstructure of the material by inhibiting the abnormal growth of grains. 2+ The lattice distortion caused by the incorporation of ions improves the material's withstand voltage characteristics and obtains a positive capacitance-temperature change rate at high temperatures, achieving a stable temperature characteristic after being combined with the dielectric layer A, thereby significantly optimizing the overall performance of the capacitor;

[0032] Fifth, through the combination of multiple element doping technology and dual dielectric ceramic materials, a new preparation method is provided for the design of high-performance electronic ceramic capacitors, which can play an important role in the miniaturization and performance improvement of electronic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the internal structure of the ceramic capacitor of the present invention;

[0034] Figure 2 The dielectric constant of the sample in Example 1 varies with temperature;

[0035] Figure 3 The capacitance change rate of the sample in Example 1 varies with temperature;

[0036] In the figure, 1-copper metal electrode, 2-nickel metal electrode, 3-dielectric layer A, 4-dielectric layer B. DETAILED DESCRIPTION

[0037] The present invention is further described below through specific implementation modes.

[0038] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layers A and B, wherein the thickness of dielectric layer A is 1-6um, and the thickness of dielectric layer B is 1-6um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0039] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100: 0.1-1.5: 0.07-0.13: 0.05-0.1: 0.2-1: 0.5-2: 0.2-1: 0.1-0.5: 0.3-0.6.

[0040] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, and nickel oxide in a molar ratio of 100: 0.1-0.5: 0.03-0.07: 0.1-0.5: 0.2-1: 0.5-2: 0.2-1: 0.1-0.5: 0.3-0.6: 0.2-0.8.

[0041] Specifically, rare earth oxide A and rare earth oxide C include at least one of Eu, Gd, Tb, Dy, and Ho oxides; rare earth oxide B and rare earth oxide D include at least one of Sc, Y, Er, Tm, Yb, and Lu oxides.

[0042] The preparation method thereof comprises the following steps:

[0043] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it with alcohol as the medium for 2-10 hours, and grind it with the bead mill until the particle size is less than 200nm to obtain the dopant slurry of dielectric layer A;

[0044] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 1-8 hours, grinding and dispersing it fully; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 2-6 hours, ball milling for 2-18 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:2-12:8-20 respectively;

[0045] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 1-6 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0046] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 2-10 hours, and grind it with the bead mill until the particle size is less than 200nm to obtain the dopant slurry of dielectric layer B;

[0047] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 1-8 hours, grinding and dispersing it fully; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 2-6 hours, ball milling for 2-18 hours, filtering, defoaming, and obtaining a casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:2-12:8-20 respectively;

[0048] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 1-6 μm, and then printing the nickel electrode slurry on the dielectric layer to form a dielectric layer B;

[0049] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0050] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0051] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 210-450° C. for degreasing for 20-86 hours.

[0052] The sintering process is as follows: The sintering environment is N 2 / H 2 / H2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 35-80:1, distilled water at 25-80℃ is humidified and passed into the furnace, and kept at 1180-1310℃ for 1-6h at a rate of 2-30℃ / min, then cooled to 800-1100℃ for oxygen recovery, with an oxygen content of 5-100ppm, kept warm for 2-10h, and then cooled to room temperature to obtain a porcelain body.

[0053] The sintering is carried out under the protection of nitrogen.

[0054] Example 1

[0055] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0056] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100:1:0.107:0.08:1:1.6:0.5:0.24:0.4.

[0057] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, and nickel oxide in a molar ratio of 100:0.4:0.05:0.3:1:1.6:0.35:0.24:0.4:0.5.

[0058] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0059] The preparation method thereof comprises the following steps:

[0060] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0061] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0062] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0063] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0064] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0065] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0066] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0067] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0068] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0069] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0070] The sintering is carried out under the protection of nitrogen.

[0071] Example 2

[0072] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0073] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100:0.6:0.127:0.06:1:1.8:0.9:0.4:0.55.

[0074] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, and nickel oxide in a molar ratio of 100:0.2:0.035:0.45:1:1.8:0.65:0.4:0.55:0.3.

[0075] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 1:9, and the molar ratio of the total rare earth content is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 1:8, and the molar ratio of the total rare earth content is 1.8 moles.

[0076] The preparation method thereof comprises the following steps:

[0077] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0078] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 6 hours, ball milling for 15 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:6:15 respectively;

[0079] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0080] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0081] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, grinding and dispersing it fully; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 6 hours, ball milling for 15 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:6:15 respectively;

[0082] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0083] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0084] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0085] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 350° C. for 50 hours of degreasing.

[0086] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 Distilled water at 45°C was humidified and passed into the furnace in a ratio of 50:1, and kept at 1210°C for 2.5 hours at a rate of 5°C / min. Then the temperature was lowered to 950°C for oxygen recovery with an oxygen content of 30ppm, and kept for 5 hours. Finally, the furnace was cooled to room temperature to obtain a porcelain body.

[0087] The sintering is carried out under the protection of nitrogen.

[0088] Example 3

[0089] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0090] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100:1.5:0.077:0.09:1:1.8:0.3:0.15:0.35.

[0091] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, and nickel oxide in a molar ratio of 100:0.46:0.007:0.19:1:1.8:0.22:0.15:0.35:0.7.

[0092] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 4:1, and the molar ratio of the total rare earth content is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 2:1, and the molar ratio of the total rare earth content is 1.8 moles.

[0093] The preparation method thereof comprises the following steps:

[0094] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0095] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:9:16 respectively;

[0096] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0097] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0098] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, grinding and dispersing it fully; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:9:16 respectively;

[0099] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0100] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0101] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0102] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 400° C. for 48 hours for degreasing.

[0103] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 38°C distilled water is humidified and passed into the furnace, and kept at 1250°C for 2 hours at a rate of 10°C / min, then cooled to 900°C for oxygen return, with an oxygen content of 30ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0104] The sintering is carried out under the protection of nitrogen.

[0105] Comparative Example 1

[0106] A temperature-characteristic controllable multilayer ceramic capacitor is formed by stacking and firing dielectric layers. Specifically, internal electrodes are printed on the dielectric layers, wherein nickel electrodes are used as internal electrodes and copper electrodes are used as external electrodes.

[0107] The dielectric layer is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100:1:0.107:0.08:1:1.6:0.5:0.24:0.4.

[0108] Specifically, the rare earth oxide A preferably consists of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; the rare earth oxide B preferably consists of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0109] The preparation method thereof comprises the following steps:

[0110] Step 1: Add the raw material composition of the dielectric layer into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dielectric layer dopant slurry;

[0111] Step 2, adding ethanol, toluene, dispersant, and dielectric layer dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining a casting slurry, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0112] Step 3, casting the casting slurry prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer;

[0113] Step 4, stacking the dielectric layers in an offset manner, and then subjecting them to water pressure and slicing to produce a ceramic green body;

[0114] Step 5: Degreasing, sintering, chamfering, copper termination, and sintering the ceramic green body are sequentially performed to obtain the multilayer ceramic capacitor.

[0115] Among them, in step five, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0116] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0117] The sintering is carried out under the protection of nitrogen.

[0118] Comparative Example 2

[0119] A temperature-characteristic controllable multilayer ceramic capacitor is formed by stacking and firing dielectric layers. Specifically, internal electrodes are printed on the dielectric layers, wherein nickel electrodes are used as internal electrodes and copper electrodes are used as external electrodes.

[0120] The dielectric layer is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, and nickel oxide in a molar ratio of 100:0.4:0.05:0.3:1:1.6:0.35:0.24:0.4:0.5.

[0121] Specifically, the rare earth oxide C is preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; the rare earth oxide D is preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0122] The preparation method thereof comprises the following steps:

[0123] Step 1: Add the raw material composition of the dielectric layer into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dielectric layer dopant slurry;

[0124] Step 2, adding ethanol, toluene, dispersant, and dielectric layer dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining a casting slurry, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0125] Step 3, casting the tape-casting slurry prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer;

[0126] Step 4, stacking the dielectric layers in an offset manner, and then subjecting them to water pressure and slicing to produce a ceramic green body;

[0127] Step 5: Degreasing, sintering, chamfering, copper termination, and sintering the ceramic green body are sequentially performed to obtain the multilayer ceramic capacitor.

[0128] Among them, in step five, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0129] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0130] The sintering is carried out under the protection of nitrogen.

[0131] Comparative Example 3

[0132] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0133] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a molar ratio of 100:1:0.107:0.08:0.5:0.24:0.4.

[0134] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and other materials in a molar ratio of 100:0.4:0.05:0.3:0.35:0.24:0.4:0.5.

[0135] The preparation method thereof comprises the following steps:

[0136] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0137] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0138] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0139] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0140] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0141] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0142] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0143] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0144] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0145] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0146] The sintering is carried out under the protection of nitrogen.

[0147] Comparative Example 4

[0148] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0149] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide B, rare earth oxide A, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100:1:0.107:0.08:1:1.6:0.5:0.24:0.4.

[0150] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide D, rare earth oxide C, silicon dioxide, calcium carbonate, zirconium oxide, and nickel oxide in a molar ratio of 100:0.4:0.05:0.3:1:1.6:0.35:0.24:0.4:0.5.

[0151] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole.

[0152] The preparation method thereof comprises the following steps:

[0153] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0154] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0155] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0156] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0157] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0158] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0159] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0160] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0161] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0162] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0163] The sintering is carried out under the protection of nitrogen.

[0164] Comparative Example 5

[0165] A temperature-characteristic controllable multilayer ceramic capacitor is formed by stacking and firing dielectric layers. Specifically, internal electrodes are printed on the dielectric layers, wherein nickel electrodes are used as internal electrodes and copper electrodes are used as external electrodes.

[0166] The dielectric layer is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a molar ratio of 100:0.4:0.05:0.3:1:1.6:0.35:0.24:0.4.

[0167] Specifically, the rare earth oxide C is preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; the rare earth oxide D is preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0168] The preparation method thereof comprises the following steps:

[0169] Step 1: Add the raw material composition of the dielectric layer into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dielectric layer dopant slurry;

[0170] Step 2, adding ethanol, toluene, dispersant, and dielectric layer dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining a casting slurry, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0171] Step 3, casting the tape-casting slurry prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer;

[0172] Step 4, stacking the dielectric layers in an offset manner, and then subjecting them to water pressure and slicing to produce a ceramic green body;

[0173] Step 5: Degreasing, sintering, chamfering, copper termination, and sintering the ceramic green body are sequentially performed to obtain the multilayer ceramic capacitor.

[0174] Among them, in step five, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0175] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0176] The sintering is carried out under the protection of nitrogen.

[0177] Comparative Example 6

[0178] A temperature-characteristic controllable multilayer ceramic capacitor is formed by stacking and firing dielectric layers. Specifically, internal electrodes are printed on the dielectric layers, wherein nickel electrodes are used as internal electrodes and copper electrodes are used as external electrodes.

[0179] The dielectric layer is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and other materials in a molar ratio of 100:1:0.107:0.08:1:1.6:0.5:0.24:0.4:0.5.

[0180] Specifically, the rare earth oxide A preferably consists of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; the rare earth oxide B preferably consists of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0181] The preparation method thereof comprises the following steps:

[0182] Step 1: Add the raw material composition of the dielectric layer into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dielectric layer dopant slurry;

[0183] Step 2, adding ethanol, toluene, dispersant, and dielectric layer dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining a casting slurry, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0184] Step 3, casting the casting slurry prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer;

[0185] Step 4, stacking the dielectric layers in an offset manner, and then subjecting them to water pressure and slicing to produce a ceramic green body;

[0186] Step 5: Degreasing, sintering, chamfering, copper termination, and sintering the ceramic green body are sequentially performed to obtain the multilayer ceramic capacitor.

[0187] Among them, in step five, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0188] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0189] The sintering is carried out under the protection of nitrogen.

[0190] Comparative Example 7

[0191] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0192] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100:1:0.107:0.08:1:1.6:0.5:0.24:0.4.

[0193] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a molar ratio of 100:0.4:0.05:0.3:1:1.6:0.35:0.24:0.4.

[0194] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0195] The preparation method thereof comprises the following steps:

[0196] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0197] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0198] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0199] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0200] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0201] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0202] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0203] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0204] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0205] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0206] The sintering is carried out under the protection of nitrogen.

[0207] Comparative Example 8

[0208] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0209] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide C, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a molar ratio of 100:1:0.107:0.08:0.5:0.5:0.5:0.24:0.4.

[0210] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide B, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and other materials in a molar ratio of 100:0.4:0.05:0.3:0.8:0.8:0.35:0.24:0.4:0.5.

[0211] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0212] The preparation method thereof comprises the following steps:

[0213] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0214] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0215] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0216] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0217] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0218] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0219] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0220] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0221] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0222] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0223] The sintering is carried out under the protection of nitrogen.

[0224] Comparative Example 9

[0225] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0226] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide B, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a molar ratio of 100:1:0.107:0.08:0.8:0.8:0.5:0.24:0.4.

[0227] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide C, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and other materials in a molar ratio of 100:0.4:0.05:0.3:0.5:0.5:0.35:0.24:0.4:0.5.

[0228] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0229] The preparation method thereof comprises the following steps:

[0230] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0231] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0232] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0233] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0234] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0235] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0236] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0237] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0238] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0239] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0240] The sintering is carried out under the protection of nitrogen.

[0241] Comparative Example 10

[0242] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0243] The dielectric layer A is composed of barium titanate, manganese tetraoxide, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a molar ratio of 100:0.107:1:1.6:0.5:0.24:0.4.

[0244] The dielectric layer B is composed of barium titanate, manganese tetraoxide, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and other materials in a molar ratio of 100:0.05:1:1.6:0.35:0.24:0.4:0.5.

[0245] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0246] The preparation method thereof comprises the following steps:

[0247] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0248] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0249] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0250] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0251] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0252] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0253] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0254] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0255] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0256] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0257] The sintering is carried out under the protection of nitrogen.

[0258] Comparative Example 11

[0259] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0260] The dielectric layer A is composed of barium titanate, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a molar ratio of 100:0.107:0.08:1:1.6:0.5:0.24:0.4.

[0261] The dielectric layer B is composed of barium titanate, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and other materials in a molar ratio of 100:0.05:0.3:1:1.6:0.35:0.24:0.4:0.5.

[0262] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0263] The preparation method thereof comprises the following steps:

[0264] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0265] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0266] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0267] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0268] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0269] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0270] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0271] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0272] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0273] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0274] The sintering is carried out under the protection of nitrogen.

[0275] Comparative Example 12

[0276] A temperature-controlled multilayer ceramic capacitor is formed by staggered stacking and firing of dielectric layer A and dielectric layer B, wherein the thickness of dielectric layer A is 2um and the thickness of dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0277] The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a molar ratio of 100:1:0.107:1:1.6:0.5:0.24:0.4.

[0278] The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and other materials in a molar ratio of 100:0.4:0.05:1:1.6:0.35:0.24:0.4:0.5.

[0279] Specifically, rare earth oxide A and rare earth oxide C are preferably composed of two elements Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth content is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth content is 1.6 moles.

[0280] The preparation method thereof comprises the following steps:

[0281] Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it for 8 hours with alcohol as the medium, and grind it into a particle size less than 200nm by the bead mill to obtain a dopant slurry of dielectric layer A;

[0282] Step 2, adding ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0283] Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A;

[0284] Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 8 hours until the particle size is less than 200nm, so as to obtain a dopant slurry of dielectric layer B;

[0285] Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 5 hours, and fully dispersing it; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 4.5 hours, ball milling for 13 hours, filtering, defoaming, and obtaining casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0286] Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 2 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B;

[0287] Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressure and slicing to produce a ceramic green body;

[0288] Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

[0289] Among them, in step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380° C. for 46 hours for degreasing.

[0290] The sintering process is as follows: The sintering environment is N 2 / H 2 / H 2 O system is sintered in a reducing atmosphere. During the sintering process, N 2 and H 2 According to the ratio of 45:1, 36°C distilled water is humidified and passed into the furnace, and kept at 1230°C for 2 hours at a rate of 5°C / min, then cooled to 1000°C for oxygen return, with an oxygen content of 25ppm, kept for 6 hours, and then cooled to room temperature to obtain a porcelain body.

[0291] The sintering is carried out under the protection of nitrogen.

[0292] The capacitors prepared in Examples 1-3 and Comparative Examples 1-12 were tested to obtain the following data, the results of which are shown in the following table:

[0293] Table 1 Test results of each capacitor

[0294]

[0295]

[0296] It can be seen from the above table that (1) Comparative Examples 1 and 2 all use a single medium. Comparative Example 1 is a single medium A, and its TCC high temperature end negative value exceeds the limit; Comparative Example 2 is a single medium B, and its TCC high temperature end positive value exceeds the limit;

[0297] (2) Comparative Examples 3 and 4 are different from rare earth doping. Comparative Example 3 does not add rare earth, its K value is small, the loss is large, and the TCC high temperature end exceeds the limit; Comparative Example 4 is that the rare earth elements A and B in the dielectric layer A are interchanged, and the rare earth elements C and D in the dielectric layer B are interchanged. Due to the inappropriate rare earth ratio, the K value is reduced, the loss is increased, the RC is also reduced, and the capacitance temperature characteristics are deteriorated;

[0298] (3) Comparative Examples 5 to 7 are different from Ni doping. Comparative Example 5 is a single dielectric B without Ni addition. It lacks Ni doping, and its grains may be larger, the degree of doneness is lower, the loss is larger, and the TCC high temperature end is negative, and a positive value cannot be obtained; Comparative Example 6 is a single dielectric A with Ni added, and the doping ratio is not appropriate, resulting in an inability to obtain a positive value at the high temperature end; Comparative Example 7 is a dual dielectric, dielectric B is not doped with Ni, the grains grow abnormally, the K value decreases, the loss decreases, and the capacitance temperature characteristics deteriorate;

[0299] (4) Comparative Examples 8 to 9 use different rare earth elements in dual dielectrics. In Comparative Example 8, dielectric layer A uses rare earth elements A and C, and dielectric layer B uses another type of rare earth elements B and D. The dielectric layers are doped with different rare earths. Due to the different types of rare earths, the K value is reduced and the capacitance-temperature characteristics exceed the limit. In Comparative Example 9, dielectric layer A uses rare earth elements B and D, and dielectric layer B uses another type of rare earth elements A and C. The dielectric layers are doped with different rare earths, resulting in a reduced K value, a reduced RC, and an over-limit capacitance-temperature characteristic.

[0300] (5) In Comparative Examples 10-12, Comparative Example 10 is without adding magnesium oxide and without adding vanadium acetylacetonate, and its K value is reduced, and the capacitance temperature characteristics are seriously deteriorated, the loss is increased, and the RC is reduced; Comparative Examples 11 and Comparative Examples 12 are without adding magnesium oxide and without adding vanadium acetylacetonate, and their K values ​​are also reduced, TCC exceeds the limit, the loss increases, and the RC is reduced;

[0301] (5) It can be seen from Examples 1 to 3 that the dual dielectric ceramic material prepared in the present application can achieve directional substitution of the A / B position of barium titanate, improve the dielectric constant and insulation resistance, and inhibit grain growth by adding NiO, and introduce Ni into the lattice by limiting the ratio of the two dielectric materials, and modifying the composition of the dopant by different ceramic materials, and the synergistic effect between different rare earth oxides. 2+ , increase lattice distortion, improve the stability of MLCC in a wide temperature range, comprehensively optimize capacitor performance, obtain high dielectric constant (>4000), lower loss (<5%), good insulation resistance (RC@25℃>5000MΩ·μF), and capacitance temperature characteristics meet EIA X7R standard and other excellent comprehensive performance.

[0302] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of implementation of the present invention. That is, equivalent changes and modifications made according to the application scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A temperature-controlled multilayer ceramic capacitor, characterized in that: It is formed by stacking and firing dielectric layers A and B in a staggered manner, wherein: The dielectric layer A is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadyl acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100: 0.1-1.5: 0.07-0.13: 0.05-0.1: 0.2-1: 0.5-2: 0.2-1: 0.1-0.5: 0.3-0.6; The dielectric layer B is composed of barium titanate, magnesium oxide, manganese tetraoxide, vanadium acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, and nickel oxide in a molar ratio of 100: 0.1-0.5: 0.03-0.07: 0.1-0.5: 0.2-1: 0.5-2: 0.2-1: 0.1-0.5: 0.3-0.6: 0.2-0.

8.

2. The temperature characteristic controllable multilayer ceramic capacitor according to claim 1, characterized in that: The rare earth oxide A and the rare earth oxide C include at least one of Eu, Gd, Tb, Dy, and Ho oxides.

3. The temperature characteristic controllable multilayer ceramic capacitor according to claim 1, characterized in that: The rare earth oxide B and the rare earth oxide D include at least one of Sc, Y, Er, Tm, Yb, and Lu oxides.

4. The temperature-characteristic controllable multilayer ceramic capacitor according to claim 1, characterized in that: The thickness of the dielectric layer A is 1-6 um, and the thickness of the dielectric layer B is 1-6 um.

5. The temperature characteristic controllable multilayer ceramic capacitor according to claim 1, characterized in that: The particle size of the barium titanate is 200-300nm.

6. The temperature characteristic controllable multilayer ceramic capacitor according to claim 1, characterized in that: The average particle size of the ceramic powder of the dielectric layer A and the dielectric layer B is less than 200 nm.

7. The method for preparing a temperature-characteristic controllable multilayer ceramic capacitor according to claim 1, characterized in that: The following steps are involved: Step 1: Add the raw material composition of dielectric layer A into a bead mill according to the proportion, and grind it with alcohol as the medium for 2-10 hours, and grind it with the bead mill until the particle size is less than 200nm to obtain the dopant slurry of dielectric layer A; Step 2: Add ethanol, toluene, dispersant, and dielectric layer A dopant slurry into a bead mill, then add barium titanate and grind for 1-8 hours to fully disperse it; Then, dioctyl phthalate and polyvinyl butyral resin are added in a weight ratio, stirred for 2-6 hours, ball milled for 2-18 hours, filtered and defoamed to obtain a casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:2-12:8-20 respectively; Step 3, casting the casting slurry A prepared in step 2 into a dielectric layer with a casting thickness of 1-6 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer A; Step 4: Add the raw material composition of dielectric layer B into a bead mill according to the ratio, and grind it with alcohol as the medium for 2-10 hours, and grind it with the bead mill until the particle size is less than 200nm to obtain the dopant slurry of dielectric layer B; Step 5, adding ethanol, toluene, dispersant, and dielectric layer B dopant slurry into a bead mill, then adding barium titanate, grinding for 1-8 hours, grinding and dispersing it fully; then adding dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stirring for 2-6 hours, ball milling for 2-18 hours, filtering, defoaming, and obtaining a casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:2-12:8-20 respectively; Step 6, casting the casting slurry B prepared in step 5 into a dielectric layer with a casting thickness of 1-6 μm, and then printing the nickel electrode slurry onto the dielectric layer to form a dielectric layer B; Step 7, the dielectric layer A and the dielectric layer B are stacked in an offset manner, and then subjected to water pressing and slicing to produce a ceramic green body; Step eight, subjecting the ceramic green body to degreasing, sintering, chamfering, copper termination, and sintering processes in sequence to obtain the multilayer ceramic capacitor.

8. The method for preparing a temperature-characteristic controllable multilayer ceramic capacitor according to claim 7, characterized in that: In step eight, the specific operation of the degreasing process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 210-450° C. for degreasing for 20-86 hours.

9. The method for preparing a temperature-characteristic controllable multilayer ceramic capacitor according to claim 7, characterized in that: In step eight, the sintering process is as follows: the sintering environment is selected to be sintered in a reducing atmosphere composed of a N2 / H2 / H2O system. During the sintering process, N2 and H2 are humidified with 25-80°C distilled water in a ratio of 35-80:1 and introduced into the furnace. The furnace is kept at 1180-1310°C for 1-6h at a rate of 2-30°C / min, and then cooled to 800-1100°C for oxygen recovery, with an oxygen content of 5-100ppm, and kept for 2-10h. The furnace is then cooled to room temperature to obtain a porcelain body.

10. The method for preparing a temperature-characteristic controllable multilayer ceramic capacitor according to claim 7, characterized in that: In step eight, sintering is performed under nitrogen protection.

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