Temperature characteristic controllable multilayer ceramic capacitor and method for manufacturing the same

Abstract

The application discloses a temperature characteristic controllable multilayer porcelain dielectric capacitor and a preparation method thereof. The multilayer porcelain dielectric capacitor is prepared by stacking and firing dielectric layer A and dielectric layer B in a staggered mode, wherein the dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, 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, trimanganese tetroxide, vanadyl acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide and nickel oxide; the multilayer porcelain dielectric capacitor defined in the application is prepared by stacking and firing the dielectric layer A and the dielectric layer B in a staggered mode, and the double dielectric layer combination is different from a traditional single dielectric layer, so that the capacitor simultaneously has the advantages of high dielectric constant and high temperature stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of porcelain dielectric capacitor preparation, and particularly relates to a temperature characteristic controllable multilayer porcelain dielectric capacitor and a preparation method thereof. BACKGROUND

[0002] In the context of rapid development of electronic information technology, multilayer porcelain dielectric capacitors (MLCC) as indispensable passive components in electronic devices, their importance is increasingly prominent. MLCC with its excellent electrical performance, plays a crucial role in a number of high-end technology fields, including but not limited to consumer electronics, automotive electronics, 5G communication, aerospace and military, etc. With the lightweight and functional integration of mobile devices, the MLCC industry is developing 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 puts higher challenges on the performance of dielectric materials.

[0003] Barium titanate as an economical and efficient ferroelectric material, due to its high dielectric constant, has been widely used in MLCC. However, the Curie temperature of pure barium titanate is low, and there is a large temperature coefficient and dielectric loss, which limits its use in high-performance applications. Therefore, improving the performance of barium titanate through 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 problem. The reduction of the thickness of the dielectric layer requires the particle size of barium titanate in the casting slurry to be more fine to ensure sufficient grain number and grain boundary to meet the requirements of capacitor for insulation resistance and safety. However, excessive refinement of particle size may damage the structure of barium titanate, increase grain defects, and affect its dielectric properties and temperature stability. At the same time, although barium titanate with 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 properties, ensure that the capacitor has good temperature characteristics, high safety, high dielectric constant, and is suitable for miniaturized MLCC applications, is the problem to be solved by the present application. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a temperature characteristic controllable multilayer porcelain dielectric capacitor and a preparation method thereof.

[0006] The present application adopts the following technical solutions:

[0007] A temperature characteristic controllable multilayer porcelain dielectric capacitor is formed by sintering the dielectric layer A and the dielectric layer B in a staggered manner, wherein,

[0008] The dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, acetylacetone vanadyl, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, 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, trimanganese tetroxide, acetylacetone vanadyl, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, 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] Further, the rare earth oxide A and the rare earth oxide C include at least one of Eu, Gd, Tb, Dy, Ho oxide.

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

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

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

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

[0015] A preparation method of a temperature characteristic controllable multilayer ceramic dielectric capacitor, comprising the following steps:

[0016] Step one, the raw material composition of the dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 2-10h, the bead mill is ground to a particle size of less than 200nm, and a dielectric layer A dopant slurry is obtained;

[0017] Step two, ethanol, toluene, dispersant, dielectric layer A dopant slurry, and then barium titanate are added to the bead mill, and are ground for 1-8h to fully disperse and grind; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 2-6h, ball milled for 2-18h, 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;

[0018] Step three, the medium layer B is prepared by casting the casting slurry B prepared in step five, and the thickness of the medium layer B is 1-6 μm, then the nickel electrode slurry is printed on the medium layer B to form the dielectric layer B;

[0019] Step four, the raw materials of the dielectric layer B are added into the bead mill in a certain proportion, and the alcohol is used as the medium to grind for 2-10 h, and the bead mill is ground to a particle size of less than 200 nm to obtain the medium layer B dopant slurry;

[0020] Step five, the alcohol, toluene, dispersing agent, medium layer B dopant slurry, and barium titanate are added into the bead mill, and then the barium titanate is ground and dispersed sufficiently for 1-8 h; then the dioctyl phthalate and polyvinyl butyral resin are added in a weight ratio, stirred for 2-6 h, and ball milled for 2-18 h, filtered and defoamed to obtain the casting slurry B, wherein the weight ratio of the barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:2-12:8-20;

[0021] Step six, the medium layer B is prepared by casting the casting slurry B prepared in step five, and the thickness of the medium layer B is 1-6 μm, then the nickel electrode slurry is printed on the medium layer B to form the dielectric layer B;

[0022] Step seven, the dielectric layer A and the dielectric layer B are overlapped with each other in a staggered manner, and then the water pressure and slicing are performed to manufacture the ceramic green body.

[0023] Step eight, the ceramic green body is sequentially subjected to the processes of debinding, sintering, chamfering, copper plating and sintering to obtain the multilayer ceramic dielectric capacitor.

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

[0025] Further, in step eight, the sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 25-80°C distilled water in a ratio of 35-80:1 and introduced into the furnace, and then the temperature is raised to 1180-1310°C at a rate of 2-30°C / min, and then the temperature is maintained for 1-6 h, and then the temperature is lowered to 800-1100°C for oxygen recovery, the oxygen content is 5-100 ppm, and the temperature is maintained for 2-10 h, and then the temperature is cooled to room temperature to obtain the ceramic body.

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

[0027] From the above description of the present application, compared with the prior art, the beneficial effects of the present application are:

[0028] First, the multilayer ceramic capacitor specified in this application is formed by stacking and firing dielectric layer A and dielectric layer B in a staggered manner. The combination of the two dielectric layers is different from the traditional single dielectric layer, which enables the capacitor to have 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 exhibits a negative value at high temperature, while the other exhibits a positive value at high temperature. The combination of the two dielectrics and the doping of the two dielectrics can achieve combined control of temperature characteristics, thereby obtaining the stability of MLCC over 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, thereby achieving better temperature controllability without sacrificing capacitor performance.

[0029] Second, the combination of double dielectric layers affects the microstructure of the microstructure, achieving low loss and high insulation resistance. The double dielectric layer affects grain growth, restricting the growth of internal structure grains. Smaller grains can reduce defects at grain boundaries, thereby reducing dielectric loss and improving insulation performance. At the same time, the doping elements of the double dielectric layer have similar composition and similar sintering shrinkage characteristics, which is beneficial for co-firing. By precisely controlling sintering, it is ensured that the two dielectric materials are uniformly distributed and combined at the microscale, thereby improving the dielectric constant and temperature stability of the capacitor.

[0030] Third, different types of rare earth doping in the double dielectric layer, in synergy with elements such as Mg and V, enable dielectric layers A and B to obtain high K values ​​and distinct temperature characteristics, respectively. The addition of rare earth elements helps control grain growth, avoids abnormal grain growth, and thus maintains the uniformity and consistency of the material, resulting in ceramic materials 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. When they are doped together, they can precisely 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. Through their synergistic effect, the temperature characteristic curve of the capacitor is precisely controlled, ensuring the performance stability at different temperatures.

[0031] Fourth, Ni doping imparts positive temperature characteristics to dielectric layer B at high temperatures. The introduction of NiO, as an effective dopant, optimizes the material's microstructure by suppressing abnormal grain growth. 2+ The lattice distortion caused by the incorporation of ions improves the voltage withstand properties of the material and gives it a positive rate of change of capacitance at high temperatures. This results in stable temperature characteristics when combined with dielectric layer A, thus significantly optimizing the overall performance of the capacitor.

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

[0033] Figure 1 It is a schematic diagram of the internal structure of the porcelain dielectric capacitor of the application;

[0034] Figure 2 It is a curve of the dielectric constant of the sample of Example 1 changing with temperature;

[0035] Figure 3 It is a curve of the capacitance change rate of the sample of Example 1 changing with temperature;

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

[0037] The application will be further described below through specific embodiments.

[0038] A temperature characteristic controllable multi-layer porcelain dielectric capacitor is prepared by stacking and firing dielectric layer A and dielectric layer B in a staggered manner, wherein the thickness of dielectric layer A is 1-6 um, and the thickness of dielectric layer B is 1-6 um; specifically, the particle size of barium titanate is 200-300 nm; and the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200 nm.

[0039] Dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, 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.

[0040] Dielectric layer B is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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; and 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 comprises the following steps:

[0043] Step one, the raw material composition of dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 2-10h, and the bead mill is ground to a particle size of less than 200nm to obtain dielectric layer A dopant slurry;

[0044] Step two, add ethanol, toluene, dispersant, dielectric layer A dopant slurry into the bead mill, then add barium titanate, grind for 1-8h, and grind and disperse fully; then add dioctyl phthalate and polyvinyl butyral resin according to the weight ratio, stir for 2-6h, ball mill for 2-18h, filter and defoam to obtain 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 three, the casting slurry A prepared in step two is cast into a dielectric layer, and the casting thickness is 1-6μm, then the nickel electrode slurry is printed on the dielectric layer to form dielectric layer A;

[0046] Step four, the raw material composition of dielectric layer B is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 2-10h, and the bead mill is ground to a particle size of less than 200nm to obtain dielectric layer B dopant slurry;

[0047] Step five, add ethanol, toluene, dispersant, dielectric layer B dopant slurry into the bead mill, then add barium titanate, grind for 1-8h, and grind and disperse fully; then add dioctyl phthalate and polyvinyl butyral resin according to the weight ratio, stir for 2-6h, ball mill for 2-18h, filter and defoam to obtain 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 six, the casting slurry B prepared in step five is cast into a dielectric layer, and the casting thickness is 1-6μm, then the nickel electrode slurry is printed on the dielectric layer to form dielectric layer B;

[0049] Step seven, the dielectric layer A and the dielectric layer B are overlapped with each other, and then subjected to water pressure and slicing to manufacture a ceramic green body;

[0050] Step eight, the ceramic green body is subjected to the processes of degreasing, sintering, chamfering, copper plating and sintering to obtain the multilayer ceramic dielectric capacitor.

[0051] 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℃ for 20-86h for degreasing.

[0052] The sintering process is as follows: the sintering environment is selected to be a reducing atmosphere composed of N2 / H2 / H2O system, in the sintering process, N2 and H2 are humidified by 25-80℃ distilled water in a ratio of 35-80:1, and then are introduced into the furnace at a rate of 2-30℃ / min, and then are kept at 1180-1310℃ for 1-6h, and then are cooled to 800-1100℃ to be oxygenated, the oxygen content is 5-100ppm, and then are kept for 2-10h, and then are cooled to room temperature, and then the porcelain body is obtained.

[0053] The affixing is performed under nitrogen protection.

[0054] Embodiment 1

[0055] A temperature characteristic controllable multilayer porcelain dielectric capacitor is prepared by sintering dielectric layer A and dielectric layer B in a staggered manner, wherein the thickness of the dielectric layer A is 2um, and the thickness of the 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 the dielectric layer A and the dielectric layer B is less than 200nm.

[0056] The dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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, trimanganese tetroxide, vanadyl 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, the rare earth oxide A and the rare earth oxide C are preferably composed of two elements of Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth is 1 mole; the rare earth oxide B and the rare earth oxide D are preferably composed of two elements of Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth is 1.6 moles.

[0059] The preparation method comprises the following steps:

[0060] In step one, the raw material composition of the dielectric layer A is added to a bead mill in a proportioning manner, and is ground for 8h with alcohol as a medium, the bead mill is ground to a particle size of less than 200nm, and then a dielectric layer A dopant slurry is obtained;

[0061] Step two, ethanol, toluene, dispersant, medium layer A dopant slurry is added into the bead mill, then barium titanate is added, grinding 5h, grinding dispersion is sufficient; Then add dioctyl phthalate, polyvinyl butyral resin according to the weight ratio, stirring 4.5h, ball milling 13h, filtering, defoaming, to obtain the casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0062] Step three, the casting slurry A prepared in step two is cast into a medium layer, the casting thickness is 2μm, then the nickel electrode slurry is printed on the medium layer to form a dielectric layer A;

[0063] Step four, the raw material composition of the dielectric layer B is added into the bead mill according to the proportion, and the alcohol is used as the medium to grind for 8h. The bead mill is ground to a particle size of less than 200nm to obtain the medium layer B dopant slurry.

[0064] Step five, ethanol, toluene, dispersant, medium layer B dopant slurry is added into the bead mill, then barium titanate is added, grinding 5h, grinding dispersion is sufficient; Then add dioctyl phthalate, polyvinyl butyral resin according to the weight ratio, stirring 4.5h, ball milling 13h, filtering, defoaming, to obtain the casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0065] Step six, the casting slurry B prepared in step five is cast into a medium layer, the casting thickness is 2μm, then the nickel electrode slurry is printed on the medium layer to form a dielectric layer B;

[0066] Step seven, the dielectric layer A and the dielectric layer B are overlapped with each other, and then the water pressure and slicing are carried out to manufacture the ceramic green body.

[0067] Step eight, the ceramic green body is sequentially subjected to the processes of debinding, sintering, chamfering, copper plating and affixing, so that the multilayer ceramic dielectric capacitor is obtained.

[0068] In step eight, the specific operation of the debinding process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46h debinding.

[0069] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1 and introduced into the furnace, the temperature is increased at a rate of 5℃ / min, and then kept at 1230℃ for 2h, then cooled to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and kept for 6h, then cooled to room temperature, to obtain the ceramic body.

[0070] The affixing is carried out under nitrogen protection.

[0071] Embodiment 2

[0072] A temperature characteristic controllable multilayer ceramic capacitor is prepared by stacking and firing dielectric layer A and dielectric layer B in staggered positions, 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; the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0073] Dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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] Dielectric layer B is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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 of Dy and Ho in a ratio of 1:9, and the molar ratio of the total rare earth amount is 1 mole; rare earth oxide B and rare earth oxide D are preferably composed of two elements of Y and Yb in a ratio of 1:8, and the molar ratio of the total rare earth amount is 1.8 moles.

[0076] The preparation method comprises the following steps:

[0077] Step one, the raw material composition of dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, the bead mill is ground to a particle size of less than 200nm, and dielectric layer A dopant slurry is obtained;

[0078] Step two, ethanol, toluene, dispersant, dielectric layer A dopant slurry, and then barium titanate are added to the bead mill, and are ground for 5h to fully disperse and grind; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 6h, and ball milled for 15h, filtered, defoamed, and dielectric slurry A is obtained, wherein the weight ratio of barium titanate, dioctyl phthalate, and polyvinyl butyral resin is 100:6:15;

[0079] Step three, the dielectric layer A prepared in step two is cast into a dielectric layer with a casting thickness of 2um, and then a nickel electrode slurry is printed onto the dielectric layer to form dielectric layer A;

[0080] Step four, the raw material composition of the dielectric layer B is added into the bead mill in proportion, and is ground for 8h with alcohol as the medium, the bead mill is ground to a particle size of less than 200nm, and a dielectric layer B dopant slurry is obtained;

[0081] Step five, ethanol, toluene, a dispersing agent, the dielectric layer B dopant slurry, and then barium titanate are added into the bead mill, and are ground for 5h to achieve sufficient grinding and dispersion; then dioctyl phthalate and polyvinyl butyral resin are added in a weight ratio, stirred for 6h, and ball milled for 15h, and then filtered and defoamed to obtain a casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:6:15 respectively;

[0082] Step six, the casting slurry B prepared in step five is cast into a dielectric layer with a casting thickness of 2um, and then a nickel electrode slurry is printed onto the dielectric layer to form a dielectric layer B;

[0083] Step seven, the dielectric layer A and the dielectric layer B are stacked in a staggered manner, and then subjected to water pressure and slicing to manufacture a ceramic green body;

[0084] Step eight, the ceramic green body is sequentially subjected to a debinding process, a sintering process, a chamfering process, a copper terminal process and a soldering process, and thus the multilayer ceramic dielectric capacitor is obtained.

[0085] In step eight, the debinding process is specifically performed as follows: the ceramic green body is placed in a nitrogen atmosphere at 350℃ for 50h for debinding.

[0086] The sintering process is specifically performed as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O, during the sintering process, N2 and H2 are humidified by passing through distilled water at 45℃ and then introduced into the furnace in a ratio of 50:1, the temperature is raised to 1210℃ at a rate of 5℃ / min and maintained for 2.5h, then the temperature is lowered to 950℃ for oxygen recovery, the oxygen content is 30ppm, and the temperature is maintained for 5h, and then the temperature is lowered to room temperature, and thus the ceramic body is obtained.

[0087] The soldering process is performed under nitrogen protection.

[0088] Example 3

[0089] A multilayer ceramic dielectric capacitor with controllable temperature characteristics is prepared by stacking and sintering a dielectric layer A and a dielectric layer B, wherein the thickness of the dielectric layer A is 2um, and the thickness of the 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 the dielectric layer A and the dielectric layer B is less than 200nm.

[0090] The dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, 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, trimanganese tetroxide, vanadyl acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, 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, the rare earth oxide A and the rare earth oxide C are preferably composed of two elements of Dy and Ho, in a ratio of 4:1, and the total molar ratio of the rare earth is 1 mol; the rare earth oxide B and the rare earth oxide D are preferably composed of two elements of Y and Yb, in a ratio of 2:1, and the total molar ratio of the rare earth is 1.8 mol.

[0093] The preparation method comprises the following steps:

[0094] Step one, the raw material composition of the dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, and the bead mill is ground to a particle size of less than 200nm to obtain the dielectric layer A dopant slurry;

[0095] Step two, ethanol, toluene, dispersant, dielectric layer A dopant slurry, and then barium titanate are added to the bead mill, and are ground for 5h to fully disperse and grind; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, and ball milled for 13h, filtered, defoamed, to obtain the casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:9:16 respectively;

[0096] Step three, the casting slurry A prepared in step two is cast into a dielectric layer, and the casting thickness is 2μm, and then the nickel electrode slurry is printed on the dielectric layer to form the dielectric layer A;

[0097] Step four, the raw material composition of the dielectric layer B is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, and the bead mill is ground to a particle size of less than 200nm to obtain the dielectric layer B dopant slurry;

[0098] Step five, ethanol, toluene, dispersant, medium layer B dopant slurry is added into the bead mill, then barium titanate is added, and it is ground for 5h, and it is fully ground and dispersed; then dioctyl phthalate, polyvinyl butyral resin is added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered, defoamed, and medium layer B casting slurry is obtained, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:9:16 respectively;

[0099] Step six, the medium layer B casting slurry prepared in step five is cast into a medium layer, and the casting thickness is 2μm, then the nickel electrode slurry is printed on the medium layer to form a dielectric layer B;

[0100] Step seven, the dielectric layer A and the dielectric layer B are overlapped with each other, and then water pressure and slicing are performed to manufacture a ceramic green body;

[0101] Step eight, the ceramic green body is sequentially subjected to the processes of debinding, sintering, chamfering, end coppering and burning, so that the multilayer ceramic dielectric capacitor is obtained.

[0102] In step eight, the specific operation of the debinding process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 400℃ for 48h debinding.

[0103] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 38℃ distilled water in a ratio of 45:1 and introduced into the furnace, and then the temperature is raised to 1250℃ at a rate of 10℃ / min, and the temperature is maintained for 2h, then the temperature is lowered to 900℃ to restore oxygen, the oxygen content is 30ppm, and the temperature is maintained for 6h, and then the temperature is lowered to room temperature, and the ceramic body is obtained.

[0104] The burning is performed under nitrogen protection.

[0105] Comparative example 1

[0106] A kind of temperature characteristic controllable multilayer ceramic dielectric capacitor is stacked and sintered by dielectric layer, specifically, internal electrode is printed on the dielectric layer, wherein nickel electrode is used as internal electrode, and copper electrode is used as external electrode.

[0107] The dielectric layer is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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, rare earth oxide A is preferably composed of Dy and Ho in a ratio of 1:1, and the total molar ratio of rare earth is 1 mole; rare earth oxide B is preferably composed of Y and Yb in a ratio of 1:1, and the total molar ratio of rare earth is 1.6 moles.

[0109] A preparation method thereof, comprising the following steps:

[0110] Step one, the raw material composition of the dielectric layer is added into the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, and the bead mill is ground to a particle size of less than 200nm to obtain a medium layer dopant slurry;

[0111] Step two, ethanol, toluene, dispersant, medium layer dopant slurry are added into the bead mill, then barium titanate is added, and is ground for 5h to fully disperse; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, and ball milled for 13h, filtered and defoamed to obtain a casting slurry, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13;

[0112] Step three, the casting slurry prepared in step two is cast into a medium layer with a casting thickness of 2μm, and then a nickel electrode slurry is printed on the medium layer to form a dielectric layer;

[0113] Step four, the dielectric layer and the dielectric layer are overlapped with each other, and then subjected to water pressure and slicing to manufacture a ceramic green body;

[0114] Step five, the ceramic green body is sequentially subjected to a debinding, sintering, chamfering, end copper and affixing process to obtain the multilayer ceramic dielectric capacitor.

[0115] In step five, the specific operation of the debinding process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46h debinding.

[0116] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 36℃ distilled water at a ratio of 45:1 and introduced into the furnace, and then sintered at a rate of 5℃ / min at 1230℃ for 2h, then cooled to 1000℃ and oxygenated, the oxygen content is 25ppm, and then sintered for 6h, and then cooled to room temperature to obtain the ceramic body.

[0117] The affixing is carried out under nitrogen protection.

[0118] Comparative example 2

[0119] A temperature characteristic controllable multilayer ceramic dielectric capacitor is prepared by stacking and sintering dielectric layers, specifically, the dielectric layer is printed with an internal electrode, wherein the nickel electrode is used as the internal electrode, and the copper electrode is used as the external electrode.

[0120] The dielectric layer is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, 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 of Dy and Ho in a ratio of 1:1, and the total molar ratio of the rare earth is 1 mole; the rare earth oxide D is preferably composed of two elements of Y and Yb in a ratio of 1:1, and the total molar ratio of the rare earth is 1.6 moles.

[0122] The preparation method comprises the following steps:

[0123] Step one, the raw materials of the dielectric layer are added to the bead mill according to the proportion, and are ground with alcohol as the medium for 8 hours, and the bead mill is ground to a particle size of less than 200 nm to obtain a dielectric layer dopant slurry;

[0124] Step two, ethanol, toluene, a dispersing agent, the dielectric layer dopant slurry, and then barium titanate are added to the bead mill, and are ground for 5 hours to fully disperse them; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5 hours, and ball milled for 13 hours, filtered and defoamed to obtain a casting slurry, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0125] Step three, the casting slurry prepared in step five is cast into a dielectric layer with a casting thickness of 2 microns, and then a nickel electrode slurry is printed onto the dielectric layer to form a dielectric layer;

[0126] Step four, the dielectric layer and the dielectric layer are overlapped with each other in a staggered manner, and then subjected to water pressure and slicing to manufacture a ceramic green body.

[0127] Step five, the ceramic green body is sequentially subjected to a debinding, sintering, chamfering, end copper, and affixing process to obtain the multilayer ceramic dielectric capacitor.

[0128] In step five, the debinding process is specifically as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46 hours for debinding.

[0129] The sintering process is specifically as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1 and introduced into the furnace, and then sintered at a rate of 5℃ / min at 1230℃ for 2 hours, then cooled to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and then sintered for 6 hours, and then cooled to room temperature to obtain the ceramic body.

[0130] The affixing is performed under nitrogen protection.

[0131] Comparative Example 3

[0132] A temperature characteristic controllable multilayer ceramic dielectric capacitor is prepared by firing dielectric layer A and dielectric layer B in staggered arrangement, 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; the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0133] Dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl acetylacetonate, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a proportion of 100:1:0.107:0.08:0.5:0.24:0.4 in terms of molar ratio.

[0134] Dielectric layer B is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl acetylacetonate, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and other materials in a proportion of 100:0.4:0.05:0.3:0.35:0.24:0.4:0.5 in terms of molar ratio.

[0135] The preparation method comprises the following steps:

[0136] Step one, the raw material composition of dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, the bead mill is ground to a particle size of less than 200nm, and dielectric layer A dopant slurry is obtained;

[0137] Step two, ethanol, toluene, dispersant, dielectric layer A dopant slurry, and then barium titanate are added to the bead mill, and are ground for 5h to fully disperse and grind; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, and ball milled for 13h, filtered, defoamed, and dielectric slurry A is obtained, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0138] Step three, the dielectric layer is prepared by casting the dielectric slurry A prepared in step two, and the casting thickness is 2um, and then the nickel electrode slurry is printed on the dielectric layer to form dielectric layer A;

[0139] Step four, the raw material composition of dielectric layer B is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, the bead mill is ground to a particle size of less than 200nm, and dielectric layer B dopant slurry is obtained;

[0140] Step five, ethanol, toluene, dispersant, medium layer B dopant slurry is added into the bead mill, then barium titanate is added, and it is ground for 5h, and it is fully ground and dispersed; then dioctyl phthalate, polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered, defoamed, and medium layer B casting slurry is obtained, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0141] Step six, the medium layer B casting slurry prepared in step five is cast into a medium layer, and the casting thickness is 2μm, then the nickel electrode slurry is printed on the medium layer to form a dielectric layer B;

[0142] Step seven, the dielectric layer A and the dielectric layer B are overlapped with each other, and then the water pressure and slicing are carried out to manufacture a ceramic green body.

[0143] Step eight, the ceramic green body is sequentially subjected to the processes of debinding, sintering, chamfering, copper plating and affixing, and thus the multilayer ceramic dielectric capacitor is obtained.

[0144] In step eight, the specific operation of the debinding process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46h debinding.

[0145] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1 and introduced into the furnace, and then the temperature is raised to 1230℃ at a rate of 5℃ / min and kept for 2h, then the temperature is lowered to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and the temperature is kept for 6h, and then the temperature is lowered to room temperature, and thus the ceramic body is obtained.

[0146] The affixing is carried out under nitrogen protection.

[0147] Comparative example 4

[0148] A temperature characteristic controllable multilayer ceramic dielectric capacitor is prepared by overlapping and sintering a dielectric layer A and a dielectric layer B, wherein the thickness of the dielectric layer A is 2um, and the thickness of the dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; the average particle size of the ceramic powder of the dielectric layer A and the dielectric layer B is less than 200nm.

[0149] The dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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, trimanganese tetroxide, vanadyl acetylacetonate, rare earth oxide D, rare earth oxide C, silicon dioxide, calcium carbonate, zirconium oxide, 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, the rare earth oxide A and the rare earth oxide C are preferably composed of two elements of Dy and Ho in a ratio of 1:1, and the total molar ratio of the rare earth is 1.6 moles; the rare earth oxide B and the rare earth oxide D are preferably composed of two elements of Y and Yb in a ratio of 1:1, and the total molar ratio of the rare earth is 1 mole.

[0152] The preparation method comprises the following steps:

[0153] Step one, the raw material composition of the dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, and the bead mill is ground to a particle size of less than 200nm to obtain the dielectric layer A dopant slurry;

[0154] Step two, ethanol, toluene, dispersant, dielectric layer A dopant slurry are added to the bead mill, then barium titanate is added, and is ground for 5h to fully disperse; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered and defoamed to obtain the casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0155] Step three, the dielectric layer A prepared in step two is cast into a dielectric layer, and the casting thickness is 2μm, then the nickel electrode slurry is printed on the dielectric layer to form the dielectric layer A;

[0156] Step four, the raw material composition of the dielectric layer B is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, and the bead mill is ground to a particle size of less than 200nm to obtain the dielectric layer B dopant slurry;

[0157] Step five, ethanol, toluene, dispersant, dielectric layer B dopant slurry are added to the bead mill, then barium titanate is added, and is ground for 5h to fully disperse; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered and defoamed to obtain the casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0158] Step six, the dielectric layer B prepared in step five is cast into a dielectric layer, and the casting thickness is 2μm, then the nickel electrode slurry is printed on the dielectric layer to form the dielectric layer B;

[0159] Step seven, the dielectric layer A and dielectric layer B are stacked with each other, and then the ceramic green body is manufactured through water pressure and slicing;

[0160] Step eight, the ceramic green body is sequentially subjected to the processes of degreasing, sintering, chamfering, end coppering and burning, so that the multilayer ceramic dielectric capacitor is obtained.

[0161] In step eight, the degreasing process is specifically performed as follows: the ceramic green body is placed in a nitrogen atmosphere at 380 DEG C for 46 hours for degreasing.

[0162] The sintering process is specifically performed as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O, during the sintering process, N2 and H2 are humidified by 36 DEG C distilled water at a ratio of 45:1 and then introduced into the furnace, the temperature is increased to 1230 DEG C at a rate of 5 DEG C / min, and then the temperature is maintained for 2 hours, then the temperature is decreased to 1000 DEG C for oxygen recovery, the oxygen content is 25 ppm, the temperature is maintained for 6 hours, and then the temperature is decreased to room temperature, so that the ceramic body is obtained.

[0163] The burning is performed under nitrogen protection.

[0164] Comparative example 5

[0165] A multilayer ceramic dielectric capacitor with controllable temperature characteristics is prepared by stacking and sintering 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, trimanganese tetroxide, vanadyl acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate and zirconium oxide, etc. 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 Dy and Ho in a ratio of 1:1, and the total molar ratio of the rare earth is 1 mole; the rare earth oxide D is preferably composed of Y and Yb in a ratio of 1:1, and the total molar ratio of the rare earth is 1.6 moles.

[0168] The preparation method comprises the following steps:

[0169] Step one, the raw materials of the dielectric layer are added to a bead mill in a predetermined ratio, and then the bead mill is ground for 8 hours with alcohol as a medium, so that the particle size is less than 200 nm, and a dielectric layer dopant slurry is obtained;

[0170] Step two, ethanol, toluene, dispersant, medium layer dopant slurry is added into the bead mill, then barium titanate is added, and it is ground for 5h to fully disperse the grinding; then dioctyl phthalate, polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered, defoamed to obtain the casting slurry, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0171] Step three, the casting slurry prepared in step five is cast into a medium layer with a casting thickness of 2μm, and then a nickel electrode slurry is printed on the medium layer to form a dielectric layer;

[0172] Step four, the dielectric layer and the dielectric layer are stacked with each other, and then water pressure and slicing are performed to manufacture a ceramic green body;

[0173] Step five, the ceramic green body is sequentially subjected to the processes of debinding, sintering, chamfering, end coppering and burning to obtain the multilayer ceramic dielectric capacitor.

[0174] In step five, the specific operation of the debinding process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46h for debinding.

[0175] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1 and introduced into the furnace, and then the temperature is raised to 1230℃ at a rate of 5℃ / min and kept for 2h, then the temperature is lowered to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and the temperature is kept for 6h, and then the temperature is cooled to room temperature to obtain the ceramic body.

[0176] The burning is performed under nitrogen protection.

[0177] Comparative example 6

[0178] A multilayer ceramic dielectric capacitor with controllable temperature characteristics is prepared by stacking and sintering dielectric layers, and the internal electrode is printed on the dielectric layer, wherein the internal electrode is a nickel electrode and the external electrode is a copper electrode.

[0179] The dielectric layer is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl acetylacetonate, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and the like, and the molar ratio is 100:1:0.107:0.08:1:1.6:0.5:0.24:0.4:0.5.

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

[0181] A preparation method thereof, comprising the following steps:

[0182] Step one, the raw material composition of the dielectric layer is added into the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, and the bead mill is ground to a particle size of less than 200nm to obtain a medium layer dopant slurry;

[0183] Step two, ethanol, toluene, dispersant, medium layer dopant slurry are added into the bead mill, then barium titanate is added, and is ground for 5h to fully disperse; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, and ball milled for 13h, filtered and defoamed to obtain a casting slurry, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0184] Step three, the casting slurry prepared in step two is cast into a medium layer with a casting thickness of 2um, and then a nickel electrode slurry is printed on the medium layer to form a dielectric layer;

[0185] Step four, the dielectric layer and the dielectric layer are stacked with each other, and then water pressure and slicing are performed to manufacture a ceramic green body;

[0186] Step five, the ceramic green body is sequentially subjected to a debinding, sintering, chamfering, end copper and affixing process to obtain the multilayer ceramic dielectric capacitor.

[0187] In step five, the specific operation of the debinding process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46h debinding.

[0188] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1 and introduced into the furnace, and then sintered at a rate of 5℃ / min at 1230℃ for 2h, then cooled to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and then sintered for 6h, and then cooled to room temperature to obtain the ceramic body.

[0189] The affixing is performed under nitrogen protection.

[0190] Comparative example 7

[0191] A multilayer ceramic dielectric capacitor with controllable temperature characteristics is prepared by stacking and sintering a dielectric layer A and a dielectric layer B, wherein the thickness of the dielectric layer A is 2um, and the thickness of the dielectric layer B is 2um; specifically, the particle size of barium titanate is 200-300nm; the average particle size of the ceramic powder of the dielectric layer A and the dielectric layer B is less than 200nm.

[0192] The dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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, trimanganese tetroxide, vanadyl acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, and zirconium oxide in a molar ratio of 100:0.4:0.05:0.3:1:1.6:0.35:0.24:0.4.

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

[0195] The preparation method comprises the following steps:

[0196] In step one, the raw materials of the dielectric layer A are added into a bead mill in a proportioning manner, and are ground for 8 hours with alcohol as a medium, so that the particle size is less than 200 nm, and a dielectric layer A dopant slurry is obtained;

[0197] In step two, alcohol, toluene, a dispersing agent, and the dielectric layer A dopant slurry are added into the bead mill, and then barium titanate is added and ground for 5 hours until it is fully dispersed; then dioctyl phthalate and polyvinyl butyral resin are added in a weight ratio of 8:13, and stirred for 4.5 hours and ball-milled for 13 hours, and then filtered and defoamed to obtain a casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate, and polyvinyl butyral resin is 100:8:13;

[0198] In step three, the casting slurry A prepared in step two is cast into a dielectric layer with a thickness of 2 microns, and then a nickel electrode slurry is printed on the dielectric layer to form the dielectric layer A;

[0199] In step four, the raw materials of the dielectric layer B are added into a bead mill in a proportioning manner, and are ground for 8 hours with alcohol as a medium, so that the particle size is less than 200 nm, and a dielectric layer B dopant slurry is obtained;

[0200] In step five, alcohol, toluene, a dispersing agent, and the dielectric layer B dopant slurry are added into the bead mill, and then barium titanate is added and ground for 5 hours until it is fully dispersed; then dioctyl phthalate and polyvinyl butyral resin are added in a weight ratio of 8:13, and stirred for 4.5 hours and ball-milled for 13 hours, and then filtered and defoamed to obtain a casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate, and polyvinyl butyral resin is 100:8:13.

[0201] Step six, the cast slurry B prepared in step five is cast into a medium layer with a cast thickness of 2 μm, and then a nickel electrode slurry is printed onto the medium layer to form a dielectric layer B;

[0202] Step seven, the dielectric layer A and the dielectric layer B are stacked in a staggered manner, and then subjected to water pressure and slicing to produce a ceramic green body.

[0203] Step eight, the ceramic green body is sequentially subjected to a debinding process, a sintering process, a chamfering process, a copper plating process, and a soldering process, to obtain the multilayer ceramic dielectric capacitor.

[0204] In step eight, the debinding process is specifically performed as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46h.

[0205] The sintering process is specifically performed as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O, during the sintering process, N2 and H2 are humidified by 36℃ distilled water at a ratio of 45:1 and then introduced into the furnace, the temperature is raised to 1230℃ at a rate of 5℃ / min and maintained for 2h, then the temperature is lowered to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and the temperature is maintained for 6h, and then the temperature is lowered to room temperature, to obtain the ceramic body.

[0206] The soldering process is performed under nitrogen protection.

[0207] Comparative Example 8

[0208] A multilayer ceramic dielectric capacitor with controllable temperature characteristics is prepared by stacking and sintering a dielectric layer A and a dielectric layer B, wherein the thickness of the dielectric layer A is 2um and the thickness of the 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 the dielectric layer A and the dielectric layer B is less than 200nm.

[0209] The dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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, trimanganese tetroxide, vanadyl 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, the rare earth oxides A and C are preferably composed of two elements of Dy and Ho, the ratio is 1:1, and the molar ratio of the total rare earth is 1 mole; the rare earth oxides B and D are preferably composed of two elements of Y and Yb, the ratio is 1:1, and the molar ratio of the total rare earth is 1.6 moles.

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

[0213] Step one, the raw material composition of the dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, the bead mill is ground to a particle size of less than 200nm, and the dielectric layer A dopant slurry is obtained;

[0214] Step two, ethanol, toluene, dispersant, dielectric layer A dopant slurry, and then barium titanate are added to the bead mill, and are ground for 5h, and are fully ground and dispersed; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered and defoamed to obtain the casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0215] Step three, the casting slurry A prepared in step two is cast into a dielectric layer, the casting thickness is 2μm, and then the nickel electrode slurry is printed on the dielectric layer to form the dielectric layer A;

[0216] Step four, the raw material composition of the dielectric layer B is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, the bead mill is ground to a particle size of less than 200nm, and the dielectric layer B dopant slurry is obtained;

[0217] Step five, ethanol, toluene, dispersant, dielectric layer B dopant slurry, and then barium titanate are added to the bead mill, and are ground for 5h, and are fully ground and dispersed; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered and defoamed to obtain the casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0218] Step six, the casting slurry B prepared in step five is cast into a dielectric layer, the casting thickness is 2μm, and then the nickel electrode slurry is printed on the dielectric layer to form the dielectric layer B;

[0219] Step seven, the dielectric layer A and the dielectric layer B are overlapped with each other in a staggered manner, and then are subjected to water pressure and slicing to manufacture a ceramic green body;

[0220] Step eight, the ceramic green body is sequentially subjected to debinding, sintering, chamfering, end coppering and sintering processes, and the multilayer ceramic dielectric capacitor is obtained.

[0221] In step eight, the specific operation of the defatting process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46h for defatting.

[0222] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O, during the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1 and then introduced into the furnace, the temperature is raised to 1230℃ at a rate of 5℃ / min and maintained for 2h, then the temperature is lowered to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and the temperature is maintained for 6h, and then cooled to room temperature to obtain the porcelain body.

[0223] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O, during the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1 and then introduced into the furnace, the temperature is raised to 1230℃ at a rate of 5℃ / min and maintained for 2h, then the temperature is lowered to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and the temperature is maintained for 6h, and then cooled to room temperature to obtain the porcelain body.

[0224] Comparative Example 9

[0225] A temperature characteristic controllable multilayer porcelain dielectric capacitor is prepared by sintering dielectric layer A and dielectric layer B in a staggered manner, 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; the average particle size of the ceramic powder of dielectric layer A and dielectric layer B is less than 200nm.

[0226] Dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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] Dielectric layer B is composed of barium titanate, magnesium oxide, trimanganese tetroxide, vanadyl 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 amount 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 amount is 1.6 moles.

[0229] The preparation method comprises the following steps:

[0230] Step one, the raw material composition of dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, the bead mill is ground to a particle size of less than 200nm, and dielectric layer A dopant slurry is obtained;

[0231] Step two, ethanol, toluene, dispersant, medium layer A dopant slurry is added into the bead mill, then barium titanate is added, grinding 5h, grinding dispersion is sufficient; Then add dioctyl phthalate, polyvinyl butyral resin according to the weight ratio, stirring 4.5h, ball milling 13h, filtering, defoaming, obtaining casting slurry A, wherein, barium titanate, dioctyl phthalate and polyvinyl butyral resin are 100:8:13 by weight ratio respectively;

[0232] Step three, the casting slurry A prepared in step two is cast into a medium layer, the casting thickness is 2μm, then the nickel electrode slurry is printed on the medium layer to form a dielectric layer A;

[0233] Step four, the raw material composition of the dielectric layer B is added into the bead mill according to the proportion, and is ground for 8h with alcohol as the medium. The bead mill is ground to a particle size of less than 200nm to obtain a medium layer B dopant slurry.

[0234] Step five, ethanol, toluene, dispersant, medium layer B dopant slurry is added into the bead mill, then barium titanate is added, grinding 5h, grinding dispersion is sufficient; Then add dioctyl phthalate, polyvinyl butyral resin according to the weight ratio, stirring 4.5h, ball milling 13h, filtering, defoaming, obtaining casting slurry B, wherein, barium titanate, dioctyl phthalate and polyvinyl butyral resin are 100:8:13 by weight ratio respectively;

[0235] Step six, the casting slurry B prepared in step five is cast into a medium layer, the casting thickness is 2μm, then the nickel electrode slurry is printed on the medium layer to form a dielectric layer B;

[0236] Step seven, the dielectric layer A and the dielectric layer B are overlapped with each other, and then subjected to water pressure and slicing to manufacture a ceramic green body.

[0237] Step eight, the ceramic green body is sequentially subjected to debinding, sintering, chamfering, copper plating and sintering processes to obtain the multilayer ceramic dielectric capacitor.

[0238] In step eight, the specific operation of the debinding process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46h debinding.

[0239] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1 and introduced into the furnace, the temperature is increased at a rate of 5℃ / min, and then kept at 1230℃ for 2h, then cooled to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and kept for 6h, then cooled to room temperature to obtain the ceramic body.

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

[0241] Comparative Example 10

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

[0243] Dielectric layer A is composed of barium titanate, trimanganese tetroxide, rare earth oxide A, rare earth oxide B, silicon dioxide, calcium carbonate, zirconium oxide and other materials in a proportion of 100:0.107:1:1.6:0.5:0.24:0.4 by mole ratio.

[0244] Dielectric layer B is composed of barium titanate, trimanganese tetroxide, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and other materials in a proportion of 100:0.05:1:1.6:0.35:0.24:0.4:0.5 by mole ratio.

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

[0246] The preparation method comprises the following steps:

[0247] Step one, the raw material composition of dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, the bead mill is ground to a particle size of less than 200nm, and dielectric layer A dopant slurry is obtained;

[0248] Step two, ethanol, toluene, dispersant, dielectric layer A dopant slurry, and then barium titanate are added to the bead mill, and are ground for 5h to fully disperse and grind; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, and ball milled for 13h, filtered and defoamed to obtain casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0249] Step three, the casting slurry A prepared in step two is cast into a dielectric layer with a casting thickness of 2um, and then a nickel electrode slurry is printed onto the dielectric layer to form dielectric layer A;

[0250] Step four, the raw material composition of dielectric layer B is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, the bead mill is ground to a particle size of less than 200nm, and dielectric layer B dopant slurry is obtained;

[0251] Step five, ethanol, toluene, dispersant, medium layer B dopant slurry is added into the bead mill, then barium titanate is added, and it is ground for 5h, and it is fully ground and dispersed; then dioctyl phthalate, polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered, defoamed, and the casting slurry B is obtained, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0252] Step six, the casting slurry B prepared in step five is cast into a medium layer, and the casting thickness is 2μm, then the nickel electrode slurry is printed on the medium layer to form a dielectric layer B;

[0253] Step seven, the dielectric layer A and the dielectric layer B are overlapped with each other, and then the water pressure and slicing are carried out to manufacture a ceramic green body.

[0254] Step eight, the ceramic green body is sequentially subjected to the processes of degreasing, sintering, chamfering, end coppering and affixing, and thus the multilayer ceramic dielectric capacitor is obtained.

[0255] 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℃ for 46h for degreasing.

[0256] The sintering process is as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O system, during the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1 and introduced into the furnace, and then the temperature is raised to 1230℃ at a rate of 5℃ / min and kept for 2h, then the temperature is lowered to 1000℃ for oxygen recovery, the oxygen content is 25ppm, and the temperature is kept for 6h, and then the temperature is cooled to room temperature, and thus the ceramic body is obtained.

[0257] The affixing is carried out under nitrogen protection.

[0258] Comparative example 11

[0259] A temperature characteristic controllable multilayer ceramic dielectric capacitor is prepared by overlapping and sintering a dielectric layer A and a dielectric layer B, wherein the thickness of the dielectric layer A is 2um, and the thickness of the 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 the dielectric layer A and the dielectric layer B is less than 200nm.

[0260] The dielectric layer A is composed of barium titanate, trimanganese tetroxide, vanadyl 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, trimanganese tetroxide, vanadyl acetylacetonate, rare earth oxide C, rare earth oxide D, silicon dioxide, calcium carbonate, zirconium oxide, nickel oxide and the like in a molar ratio of 100:0.05:0.3:1:1.6:0.35:0.24:0.4:0.5.

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

[0263] The preparation method comprises the following steps:

[0264] Step one, the raw material composition of the dielectric layer A is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, and the bead mill is ground to a particle size of less than 200nm to obtain the dielectric layer A dopant slurry;

[0265] Step two, ethanol, toluene, dispersant, dielectric layer A dopant slurry are added to the bead mill, then barium titanate is added, and is ground for 5h to fully disperse; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered and defoamed to obtain the casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0266] Step three, the dielectric layer is cast from the casting slurry A prepared in step two, and the casting thickness is 2μm, then the nickel electrode slurry is printed on the dielectric layer to form the dielectric layer A;

[0267] Step four, the raw material composition of the dielectric layer B is added to the bead mill according to the proportion, and is ground with alcohol as the medium for 8h, and the bead mill is ground to a particle size of less than 200nm to obtain the dielectric layer B dopant slurry;

[0268] Step five, ethanol, toluene, dispersant, dielectric layer B dopant slurry are added to the bead mill, then barium titanate is added, and is ground for 5h to fully disperse; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, ball milled for 13h, filtered and defoamed to obtain the casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0269] Step six, the dielectric layer is cast from the casting slurry B prepared in step five, and the casting thickness is 2μm, then the nickel electrode slurry is printed on the dielectric layer to form the dielectric layer B;

[0270] Step seven, the dielectric layer A and dielectric layer B are stacked with each other, and then the ceramic green body is manufactured through water pressure and slicing;

[0271] Step eight, the ceramic green body is sequentially subjected to the processes of debinding, sintering, chamfering, copper plating and soldering, so that the multilayer ceramic dielectric capacitor is obtained.

[0272] In step eight, the debinding process is specifically performed as follows: the ceramic green body is placed in a nitrogen atmosphere at 380 DEG C for 46 hours for debinding.

[0273] The sintering process is specifically performed as follows: the sintering environment is a reducing atmosphere composed of N2 / H2 / H2O, during the sintering process, N2 and H2 are humidified by 36 DEG C distilled water at a ratio of 45:1 and then introduced into the furnace, the temperature is raised to 1230 DEG C at a rate of 5 DEG C / min and maintained for 2 hours, then the temperature is lowered to 1000 DEG C for oxygen recovery, the oxygen content is 25 ppm, maintained for 6 hours, and then cooled to room temperature, so that the ceramic body is obtained.

[0274] The soldering is performed under nitrogen protection.

[0275] Comparative example 12

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

[0277] The dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, 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, trimanganese tetroxide, 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, the rare earth oxide A and the rare earth oxide C are preferably composed of two elements of Dy and Ho in a ratio of 1:1, and the molar ratio of the total rare earth is 1 mole; the rare earth oxide B and the rare earth oxide D are preferably composed of two elements of Y and Yb in a ratio of 1:1, and the molar ratio of the total rare earth is 1.6 moles.

[0280] The preparation method comprises the following steps:

[0281] Step one, the raw material composition of dielectric layer A is added into the bead mill according to the proportion, and is ground for 8h with alcohol as the medium, the bead mill is ground to a particle size of less than 200nm, and the dielectric layer A dopant slurry is obtained;

[0282] Step two, ethanol, toluene, dispersant, dielectric layer A dopant slurry, and then barium titanate are added into the bead mill, and are ground for 5h, and the grinding and dispersion are sufficient; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, and ball milled for 13h, filtered and defoamed to obtain the casting slurry A, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0283] Step three, the casting slurry A prepared in step two is cast into a dielectric layer, and the casting thickness is 2μm, then the nickel electrode slurry is printed on the dielectric layer to form the dielectric layer A;

[0284] Step four, the raw material composition of dielectric layer B is added into the bead mill according to the proportion, and is ground for 8h with alcohol as the medium, the bead mill is ground to a particle size of less than 200nm, and the dielectric layer B dopant slurry is obtained;

[0285] Step five, ethanol, toluene, dispersant, dielectric layer B dopant slurry, and then barium titanate are added into the bead mill, and are ground for 5h, and the grinding and dispersion are sufficient; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 4.5h, and ball milled for 13h, filtered and defoamed to obtain the casting slurry B, wherein the weight ratio of barium titanate, dioctyl phthalate and polyvinyl butyral resin is 100:8:13 respectively;

[0286] Step six, the casting slurry B prepared in step five is cast into a dielectric layer, and the casting thickness is 2μm, then the nickel electrode slurry is printed on the dielectric layer to form the dielectric layer B;

[0287] Step seven, the dielectric layer A and the dielectric layer B are overlapped with each other in a staggered manner, and then are subjected to water pressure and slicing to manufacture a ceramic green body;

[0288] Step eight, the ceramic green body is sequentially subjected to debinding, sintering, chamfering, copper plating and sintering processes, and the multilayer ceramic dielectric capacitor is obtained.

[0289] In step eight, the specific operation of the debinding process is as follows: the ceramic green body is placed in a nitrogen atmosphere at 380℃ for 46h for debinding.

[0290] The sintering process is as follows: the sintering environment is selected to be a reducing atmosphere composed of N2 / H2 / H2O system, in the sintering process, N2 and H2 are humidified by 36℃ distilled water in a ratio of 45:1, and then introduced into the furnace, at a rate of 5℃ / min, and then kept at 1230℃ for 2h, and then cooled to 1000℃ and oxygenated, the oxygen content is 25ppm, and kept for 6h, and then cooled to room temperature, to obtain the porcelain body.

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

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

[0293] Test results of each capacitor in Table 1

[0294]

[0295]

[0296] From the above table, (1) Comparative Examples 1-2 are both single media, Comparative Example 1 is single medium A, and the negative value of TCC at high temperature is out of limit; Comparative Example 2 is single medium B, and the positive value of TCC at high temperature is out of limit;

[0297] (2) Comparative Examples 3-4 are different from rare earth doping, Comparative Example 3 does not add rare earth, and the K value is small, the loss is large, and the TCC at high temperature is out of limit; Comparative Example 4 is that the rare earth elements A and B in medium layer A are exchanged, and the rare earth elements C and D in medium layer B are exchanged, because the rare earth ratio is not appropriate, the K value decreases, the loss increases, the RC also decreases, and the capacitor temperature characteristic deteriorates;

[0298] (3) Comparative Examples 5-7 are different from Ni doping, Comparative Example 5 is single medium B without adding Ni, and the crystal grains may be large, the sintering degree is low, the loss is large, and the TCC at high temperature is negative, which cannot obtain a positive value; Comparative Example 6 is single medium A with Ni added, and the doping ratio is not appropriate, which cannot obtain a positive value at high temperature; Comparative Example 7 is a double medium, medium B does not add Ni, the crystal grains grow abnormally, the K value decreases, the loss decreases, and the capacitor temperature characteristic deteriorates;

[0299] (4) Comparative Examples 8-9 are different in rare earth species in the double medium, in Comparative Example 8, medium layer A uses rare earth elements A and C, and medium layer B uses another type of rare earth elements B and D, the medium layer is different in rare earth doping, because the rare earth species are different, the K value decreases, and the capacitor temperature characteristic is out of limit; in Comparative Example 9, medium layer A uses rare earth elements B and D, and medium layer B uses another type of rare earth elements A and C, the medium layer is different in rare earth doping, which leads to a decrease in K value, a decrease in RC, and the capacitor temperature characteristic is also out of limit;

[0300] (5) In Comparative Examples 10-12, Comparative Example 10 is without the addition of magnesium oxide and without the addition of vanadyl acetylacetonate, the K value is reduced, and the capacitor temperature characteristic is seriously deteriorated, the loss is increased, and the RC is reduced; Comparative Example 11 and Comparative Example 12 are without the addition of magnesium oxide and without the addition of vanadyl acetylacetonate, the K value is also reduced, the TCC is out of limit, the loss is increased, and the RC is reduced;

[0301] (5) As can be known from Examples 1-3, the double dielectric ceramic material prepared in the application can realize the A / B site directional substitution of barium titanate by limiting the ratio of the two dielectric materials and by the synergistic effect between different rare earth oxides through the modification of the composition of the dopant of different ceramic materials, improve the dielectric constant and insulation resistance, and the addition of NiO inhibits the grain growth, introduces Ni into the lattice 2+ , increases the lattice distortion, improves the stability of the MLCC in a wide temperature range, comprehensively optimizes the capacitor performance, and obtains excellent comprehensive performance such as high dielectric constant (>4000), low loss (<5%), good insulation resistance (RC@25℃>5000MΩ·μF), and capacitor temperature characteristic meeting the EIA X7R standard.

[0302] The above is only a preferred embodiment of the application, and therefore cannot limit the scope of the application, that is, equivalent changes and modifications made according to the scope of the application and the content of the specification should still be within the scope of the application.

Claims

1. A temperature characteristic controllable multilayer ceramic dielectric capacitor, characterized by: The dielectric layer A and the dielectric layer B are stacked and fired in staggered positions. The dielectric layer A is composed of barium titanate, magnesium oxide, trimanganese tetroxide, 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, trimanganese tetroxide, vanadyl 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. The rare earth oxide A and the rare earth oxide C include at least one of Eu, Gd, Tb, Dy, and Ho oxides. The rare earth oxide B and the rare earth oxide D include at least one of Sc, Y, Er, Tm, Yb, and Lu oxides.

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

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

4. The temperature characteristic controllable multilayer ceramic dielectric 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 200nm.

5. The method of claim 1, wherein the temperature characteristic controllable multilayer ceramic dielectric capacitor is prepared by the steps of: The method comprises the following steps: ​ Step one, the raw material composition of the dielectric layer A is added to a bead mill in a proportioning manner, and is ground in alcohol as a medium for 2-10 hours, and the bead mill is ground to a particle size of less than 200nm to obtain a dielectric layer A dopant slurry; Step two, ethanol, toluene, a dispersing agent, and the dielectric layer A dopant slurry are added to a bead mill, and then barium titanate is added, and is ground for 1-8 hours to fully disperse and grind the barium titanate; 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 three, the casting slurry A prepared in step two is cast into a dielectric layer with a casting thickness of 1-6um, and then a nickel electrode slurry is printed on the dielectric layer to form a dielectric layer A; Step four, the raw material composition of the dielectric layer B is added to a bead mill in a proportioning manner, and is ground in alcohol as a medium for 2-10 hours, and the bead mill is ground to a particle size of less than 200nm to obtain a dielectric layer B dopant slurry; Step five, ethanol, toluene, a dispersing agent, and the dielectric layer B dopant slurry are added to a bead mill, and then barium titanate is added, and is ground for 1-8 hours to fully disperse and grind the barium titanate; 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 B, wherein the weight ratio of barium titanate, dioctyl phthalate, and polyvinyl butyral resin is 100:2-12:8-20 respectively. Step six, the casting slurry B prepared in step five is cast into a medium layer with a casting thickness of 1-6 μm, and then a nickel electrode slurry is printed onto the medium layer to form a dielectric layer B; Step seven, the dielectric layer A and the dielectric layer B are stacked with each other in a staggered manner, and then water pressure and slicing are performed to manufacture a ceramic green body; Step eight, the ceramic green body is sequentially subjected to a debinding process, a sintering process, a chamfering process, a copper terminal attaching process and a soldering process, so that the multilayer ceramic dielectric capacitor is obtained.

6. The method of claim 5, wherein the temperature characteristic of the multilayer ceramic capacitor is controlled by adjusting the thickness of the dielectric layer. In step eight, the debinding process is specifically performed as follows: the ceramic green body is placed in a nitrogen atmosphere at 210-450 ℃ for 20-86 h for debinding.

7. The method of claim 5, wherein the temperature coefficient of capacitance is controlled by adjusting the thickness of the dielectric layers. In step eight, the sintering process is specifically performed as follows: a reducing atmosphere composed of N2 / H2 / H2O is selected for sintering, in the sintering process, N2 and H2 are humidified by 25-80 ℃ distilled water at a ratio of 35-80:1 and then introduced into the furnace, the temperature is raised at a rate of 2-30 ℃ / min to 1180-1310 ℃ and kept for 1-6 h, then the temperature is lowered to 800-1100 ℃ for oxygen recovery, the oxygen content is 5-100 ppm, the temperature is kept for 2-10 h, and then the temperature is lowered to room temperature, so that the ceramic body is obtained.

8. The method of claim 5, wherein the temperature coefficient of capacitance is controlled by adjusting the thickness of the dielectric layers. In step eight, the soldering is performed under nitrogen protection.

Images