Anti-reduction BME ceramic dielectric capacitor and ceramic material for capacitor
阅读说明：本技术 一种抗还原bme瓷介电容器及电容器用陶瓷材料 (Anti-reduction BME ceramic dielectric capacitor and ceramic material for capacitor ) 是由 洪志超 陈本夏 喻巧 陈永虹 宋运雄 于 2020-12-24 设计创作，主要内容包括：一种抗还原BME瓷介电容器及电容器用陶瓷材料,一种抗还原BME瓷介电容器用陶瓷材料,由以下原料组成：钛酸钡、草酸氧钒、硝酸锰、硝酸镁、硝酸锶、稀土A硝酸盐、稀土B硝酸盐、硝酸铬、硝酸钡、碳酸氢钙、纳米二氧化硅、纳米二氧化铪,通过添加草酸氧钒、硝酸钡、碳酸氢钙、纳米二氧化硅、纳米二氧化铪等添加剂,降低损耗,提高绝缘电阻,提高介质耐电压,获得良好的电性能。(An anti-reduction BME ceramic capacitor and a ceramic material for the capacitor, the ceramic material for the anti-reduction BME ceramic capacitor is composed of the following raw materials: barium titanate, vanadyl oxalate, manganese nitrate, magnesium nitrate, strontium nitrate, rare earth nitrate A, rare earth nitrate B, chromium nitrate, barium nitrate, calcium bicarbonate, nano silicon dioxide, nano hafnium dioxide and other additives are added, so that the loss is reduced, the insulation resistance is improved, the dielectric withstand voltage is improved, and good electrical property is obtained.)
1. A ceramic material for an anti-reduction BME ceramic dielectric capacitor is characterized in that: the composition is characterized by comprising the following raw materials in parts by weight: 100 parts of barium titanate, 0.01-0.07 part of vanadyl oxalate, 0.15-0.46 part of manganese nitrate, 0.12-0.64 part of magnesium nitrate, 0.18-1.00 part of strontium nitrate, 0.94-4.62 parts of rare earth A nitrate, 0.15-1.51 parts of rare earth B nitrate, 0.10-0.41 part of chromium nitrate, 0.22-0.68 part of barium nitrate, 0.13-0.42 part of calcium bicarbonate, 0.12-0.52 part of nano silicon dioxide and 0.18-0.50 part of nano hafnium dioxide;
the preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate, nano silicon dioxide and nano hafnium dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring to ensure that the additive is completely dissolved;
step three, adding barium titanate, nano silicon dioxide and nano hafnium dioxide into the solution obtained in the step two, carrying out nodular stirring while carrying out ultrasonic dispersion with the ultrasonic frequency of 20-40kHz, so that the barium titanate, the nano silicon dioxide and the nano hafnium dioxide are uniformly dispersed in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 2-5MHz, the temperature of a thermal decomposition chamber is 400-600 ℃, and the sintering temperature is 800-1100 ℃, so that the precursor mixed liquid is subjected to atomization, drying, hot air blower and sintering processes to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, and the ceramic material for the anti-reduction BME ceramic is obtained.
2. The ceramic material for an anti-reduction BME ceramic dielectric capacitor as claimed in claim 1, wherein: the rare earth A nitrate is one or two of yttrium nitrate and ytterbium nitrate; the rare earth B nitrate is one or more of dysprosium nitrate, holmium nitrate and erbium nitrate.
3. The ceramic material for an anti-reduction BME ceramic dielectric capacitor as claimed in claim 1, wherein: the particle size of the nano silicon dioxide and the nano hafnium oxide is less than 50 nm.
4. The ceramic material for an anti-reduction BME ceramic dielectric capacitor as claimed in claim 1, wherein: the particle size of the barium carbonate is less than 300 nm.
5. The ceramic material for an anti-reduction BME ceramic dielectric capacitor as claimed in claim 1, wherein: in the second step, the weight ratio of the soluble salt additive to the deionized water is 1: 1-2.
6. An anti-reduction BME ceramic dielectric capacitor is characterized in that: the ceramic material for the anti-reduction BME ceramic dielectric capacitor as claimed in any one of claims 1 to 5 is prepared by the procedures of ceramic slurry refining, coating, printing, laminating, slicing, degreasing, sintering, end attaching and the like, wherein the sintering conditions are as follows: sintering in reducing atmosphere while introducing H2/N2Is 1: 30-70, humidifying at the same time, preserving the heat for 1-4h at the temperature of 1180-1250 ℃, then cooling to 800-1000 ℃ for oxygen return with the oxygen content of 5-20ppm, preserving the heat for 2-6h, and cooling to the room temperature.
7. The anti-reduction BME ceramic dielectric capacitor of claim 6, wherein: the refining of the porcelain slurry specifically comprises the following steps: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:15-30: 0.5-2, respectively adding the ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 1-8h, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral ester at a ratio of 100:3-10:5-20, and continuously ball-milling for 1-8h to obtain casting slurry.
8. The anti-reduction BME ceramic dielectric capacitor of claim 6, wherein: in the coating process, the coating thickness is less than or equal to 8 um.
9. The anti-reduction BME ceramic dielectric capacitor of claim 6, wherein: in the printing step, the internal electrode used is a nickel metal electrode.
10. The anti-reduction BME ceramic dielectric capacitor of claim 6, wherein: in the end-attaching step, the end-attaching external electrode used is a copper metal electrode.
Technical Field
The invention belongs to the field of preparation of ceramic dielectric capacitors, and particularly relates to an anti-reduction BME ceramic dielectric capacitor and a ceramic material for the capacitor.
Background
With the development of miniaturization and multi-functionalization of electronic products, the surface mounting technology is widely applied and developed. A Multilayer Ceramic Capacitor (MLCC) is one of the most widely used chip components in surface mount technology. With the increasing demand for smaller and higher performance electronic devices, multilayer ceramic capacitors are required to have smaller size, larger capacity, higher reliability, and lower cost.
The multilayer ceramic capacitor adopts a tape casting-co-firing process, and the electrode layer and the dielectric layer are mutually superposed through tape casting, printing and laminating, and then are degreased, sintered and terminated to prepare the multilayer ceramic capacitor. The traditional multilayer ceramic capacitor adopts noble metals such as palladium or palladium-silver alloy and the like as the inner electrode, and has high production cost. In order to reduce the cost, base metals such as nickel and copper can be used as the inner electrode instead of noble metals. Since base metals are oxidized when sintered in an air atmosphere, they need to be fired in a reducing atmosphere. On the other hand, since pure barium titanate is reduced by firing in a reducing atmosphere to produce semiconductors and lower the insulation resistance, a ceramic material is suitable for firing in a reducing atmosphere by adding elements such as manganese, magnesium, and rare earth to barium titanate to obtain a multilayer ceramic capacitor having high insulation resistance and high reliability.
The higher dielectric constant and the thinner dielectric layer thickness are advantageous for the miniaturization and the large capacity of the multilayer ceramic capacitor. Therefore, it is an object of the present invention to provide a dielectric ceramic material which has good temperature characteristics of capacitance, high dielectric constant, low loss, and anti-reduction characteristics, and is suitable for manufacturing ultra-thin dielectric multilayer ceramic capacitors. In patent CN101183610B, the particle size of the powder is 100-150 nm, the dielectric constant is 2000-2500, but the chemical coating method is adopted, the process is complex, the production efficiency is low, and the method is not suitable for large-scale industrial production. Therefore, the problem to be solved by the present invention is how to perform doping more uniformly and efficiently to obtain a dielectric ceramic material with ultra-fine grains, uniform particle size and excellent performance, and the dielectric ceramic material can be applied to base metals, ultra-thin dielectric layers and large-capacity multilayer ceramic capacitors.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a ceramic material for an anti-reduction BME ceramic dielectric capacitor, and the invention also aims to provide the anti-reduction BME ceramic dielectric capacitor prepared by adopting the ceramic material.
The invention adopts the following technical scheme:
a ceramic material for an anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.01-0.07 part of vanadyl oxalate, 0.15-0.46 part of manganese nitrate, 0.12-0.64 part of magnesium nitrate, 0.18-1.00 part of strontium nitrate, 0.94-4.62 parts of rare earth A nitrate, 0.15-1.51 parts of rare earth B nitrate, 0.10-0.41 part of chromium nitrate, 0.22-0.68 part of barium nitrate, 0.13-0.42 part of calcium bicarbonate, 0.12-0.52 part of nano silicon dioxide and 0.18-0.50 part of nano hafnium dioxide;
the preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate, nano silicon dioxide and nano hafnium dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring to ensure that the additive is completely dissolved;
step three, adding barium titanate, nano silicon dioxide and nano hafnium dioxide into the solution obtained in the step two, carrying out nodular stirring while carrying out ultrasonic dispersion with the ultrasonic frequency of 20-40kHz, so that the barium titanate, the nano silicon dioxide and the nano hafnium dioxide are uniformly dispersed in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 2-5MHz, the temperature of a thermal decomposition chamber is 400-600 ℃, and the sintering temperature is 800-1100 ℃, so that the precursor mixed liquid is subjected to atomization, drying, hot air blower and sintering processes to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, and the ceramic material for the anti-reduction BME ceramic is obtained.
Further, the rare earth A nitrate is one or two of yttrium nitrate and ytterbium nitrate; the rare earth B nitrate is one or more of dysprosium nitrate, holmium nitrate and erbium nitrate.
Furthermore, the particle size of the nano silicon dioxide and the nano hafnium oxide is less than 50 nm.
Further, the particle size of the barium carbonate is less than 300 nm.
Further, in the second step, the weight ratio of the soluble salt additive to the deionized water is 1: 1-2.
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting the ceramic material for the anti-reduction BME ceramic dielectric capacitor, and performing the working procedures of ceramic slurry refining, coating, printing, laminating, slicing, degreasing, sintering, end attaching and the like, wherein the sintering conditions are as follows: sintering in reducing atmosphere while introducing H2/N2Is 1: 30-70, humidifying at the same time, preserving the heat for 1-4h at the temperature of 1180-1250 ℃, then cooling to 800-1000 ℃ for oxygen return with the oxygen content of 5-20ppm, preserving the heat for 2-6h, and cooling to the room temperature.
Further, the refining of the porcelain slurry specifically comprises the following steps: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:15-30: 0.5-2, respectively adding the ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 1-8h, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral ester at a ratio of 100:3-10:5-20, and continuously ball-milling for 1-8h to obtain casting slurry.
The anti-reduction BME ceramic dielectric capacitor of claim 6, wherein: in the coating process, the coating thickness is less than or equal to 8 um.
Further, in the printing step, the internal electrode used is a nickel metal electrode.
Further, in the terminal attaching step, the terminal attaching external electrode used is a copper metal electrode.
As can be seen from the above description of the present invention, compared with the prior art, the beneficial effects of the present invention are:
firstly, the ceramic material for the anti-reduction BME ceramic dielectric capacitor reduces loss, improves insulation resistance, improves dielectric withstand voltage and obtains good electrical property by adding additives such as vanadyl oxalate, barium nitrate, calcium bicarbonate, nano silicon dioxide, nano hafnium dioxide and the like; wherein, the strontium nitrate is added to be matched with the manganese nitrate and the calcium bicarbonate, so that the oxygen vacancy of the material can be reduced in the sintering process, the reducing resistance of the material is improved, and the loss is reduced; the nano hafnium oxide is added to be matched with strontium nitrate and chromium nitrate, so that the barium titanate can be simultaneously substituted at the A/B position, the dielectric constant of the system is improved, the reducing resistance is further improved, the loss is reduced, and meanwhile, the nano hafnium oxide is matched with the nano silicon dioxide, so that the crystal boundary components and the crystal grain size can be controlled, the insulation resistance and the voltage resistance are improved, and the product reliability is improved;
secondly, by limiting the composition of the ceramic raw material, taking barium titanate as a base and magnesium nitrate and rare earth nitrate as a main system, a good shell-core structure is formed during sintering, and a stable medium temperature characteristic curve is obtained; adding anti-reduction additives such as strontium nitrate, manganese nitrate, chromium nitrate and the like to enable the material to be suitable for sintering in a reducing atmosphere; and because of less total additive content, 3000-3500 high dielectric constant can be obtained while the temperature change rate of the capacitor is kept within the range of +/-15 percent;
thirdly, the precursor mixed solution is atomized, dried, thermally decomposed and sintered by adopting an ultrasonic spray thermal decomposition granulation method to form powder with nano-scale oxides uniformly dispersed on barium titanate particles, and meanwhile, the particle size of the selected barium titanate is less than 300nm, and the particle size of the selected nano silicon dioxide/nano hafnium dioxide is less than 50nm, so that the material prepared by the method has the advantages of uniform dispersion and superfine particle size, and can be applied to an ultrathin medium layer high-capacity MLCC product;
fourthly, during preparation, the feeding sequence and the ball milling time of all the raw materials are limited, the raw materials except the barium titanate and the nano silicon dioxide are dissolved in deionized water, then the barium titanate, the nano silicon dioxide and the nano hafnium dioxide are added, and ultrasonic dispersion is carried out simultaneously, so that all the added elements are uniformly distributed, powder with uniform component and particle size distribution is obtained during ultrasonic spray pyrolysis granulation, and a shell-core structure with good uniformity is formed during sintering.
Drawings
FIG. 1 is a schematic diagram of an ultrasonic spray pyrolysis granulation apparatus provided by the present invention;
FIG. 2 is a schematic structural diagram of a ceramic material for a ceramic capacitor;
FIG. 3 is a schematic diagram of the internal structure of the ceramic capacitor according to the present invention;
FIG. 4 is a graph of the change in dielectric constant with temperature for the sample of example 1;
FIG. 5 is a graph of the rate of change of capacitance with temperature for the samples of example 1;
in the figure, 1-ceramic material, 2-nickel metal inner electrode, 3-copper metal electrode, 4-ultrasonic atomizer, 5-thermal decomposition chamber, 6-sintering chamber, 7-cyclone powder collector, 8-tail gas treatment device, 41-liquid inlet pipe, 42-air inlet pipe and 51-temperature control furnace.
Detailed Description
The invention is further described below by means of specific embodiments.
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:15-30: 0.5-2, respectively adding the ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 1-8h, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral ester at a ratio of 100:3-10:5-20, and continuously performing ball milling for 1-8h to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 30-70, humidifying at the same time, preserving the heat for 1-4h at the temperature of 1180-1250 ℃, then cooling to 800-20 ppm, restoring the oxygen at the temperature of 1000 ℃, preserving the heat for 2-6h, and cooling to the room temperature;
step six, carrying out end attachment: the end attached external electrode is a copper metal electrode 3, the sintering temperature is 900 ℃ plus 700 ℃, nitrogen protection is adopted, the temperature is kept for 0.5-2h, and after cooling, the BME ceramic dielectric capacitor is obtained.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.01-0.07 part of vanadyl oxalate, 0.15-0.46 part of manganese nitrate, 0.12-0.64 part of magnesium nitrate, 0.18-1.00 part of strontium nitrate, 0.94-4.62 parts of rare earth A nitrate, 0.15-1.51 parts of rare earth B nitrate, 0.10-0.41 part of chromium nitrate, 0.22-0.68 part of barium nitrate, 0.13-0.42 part of calcium bicarbonate, 0.12-0.52 part of nano silicon dioxide and 0.18-0.50 part of nano hafnium dioxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate, nano silicon dioxide and nano hafnium dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 4-8 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1-2;
step three, adding barium titanate, nano silicon dioxide and nano hafnium dioxide into the solution obtained in the step two, carrying out nodular stirring while carrying out ultrasonic dispersion with the ultrasonic frequency of 20-40kHz, so that the barium titanate, the nano silicon dioxide and the nano hafnium dioxide are uniformly dispersed in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 2-5MHz, the temperature of a thermal decomposition chamber is 400-600 ℃, and the sintering temperature is 800-1100 ℃, so that the precursor mixed liquid is subjected to atomization, drying, hot air blower and sintering processes to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, and the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein, the nitrate of the rare earth A is one or two of yttrium nitrate and ytterbium nitrate, and the nitrate of the rare earth B is one or more of dysprosium nitrate, holmium nitrate and erbium nitrate.
Wherein the particle size of the nano silicon dioxide and the nano hafnium oxide is less than 50nm, and the particle size of the barium carbonate is less than 300 nm.
In the fourth step, the precursor mixed liquor is fired into the ceramic material for the anti-reduction BME ceramic by adopting the device shown in figure 1, the device comprises an ultrasonic atomizer 4, a thermal decomposition chamber 5, a sintering chamber 6, a cyclone powder collector 7 and a tail gas treatment device 8 which are sequentially connected, and specifically, the ultrasonic atomizer 4 comprises a liquid inlet pipe 41 for the precursor mixed liquor to enter and an air inlet pipe 42 for compressed air to enter; the pyrolysis chamber 5 is provided with a temperature-controlled furnace 51.
Example 1
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:20: 1, respectively adding a ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 5 hours, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:5:10, and continuing ball milling for 5 hours to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 50, humidifying at the same time, preserving heat for 2h at 1220 ℃, then cooling to 900 ℃ for oxygen return with the oxygen content of 12ppm, preserving heat for 4h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 850 ℃, the temperature is kept for 1h under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.027 part of vanadyl oxalate, 0.307 part of manganese nitrate, 0.318 part of magnesium nitrate, 0.454 part of strontium nitrate, 1.847 parts of ytterbium nitrate, 0.301 part of holmium nitrate, 0.204 part of chromium nitrate, 0.336 part of barium nitrate, 0.208 part of calcium bicarbonate, 0.309 part of nano-silica and 0.271 part of nano-hafnium dioxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate, nano silicon dioxide and nano hafnium dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 6 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1.5;
step three, adding barium titanate, nano silicon dioxide and hafnium dioxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with ultrasonic frequency of 30kHz to uniformly disperse the barium titanate, the nano silicon dioxide and the nano hafnium dioxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 4MHz, the temperature of a thermal decomposition chamber is 500 ℃, the sintering temperature is 950 ℃, and the precursor mixed liquid is atomized, dried, heated by an air heater and sintered to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein, the nitrate of the rare earth A is one or two of yttrium nitrate and ytterbium nitrate, and the nitrate of the rare earth B is one or more of dysprosium nitrate, holmium nitrate and erbium nitrate.
Wherein the particle size of the nano silicon dioxide and the nano hafnium oxide is less than 50nm, and the particle size of the barium carbonate is less than 300 nm.
Example 2
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:15: 0.5, respectively adding the ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 1h, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:3:20, and continuing ball milling for 1h to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 30, humidifying at the same time, preserving heat for 4h at 1180 ℃, then cooling to 800 ℃ for oxygen return, keeping the oxygen content at 5ppm, preserving heat for 6h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 700 ℃, the temperature is kept for 2 hours under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.010 part of vanadyl oxalate, 0.150 part of manganese nitrate, 0.120 part of magnesium nitrate, 0.180 part of strontium nitrate, 0.940 part of ytterbium nitrate, 0.150 part of holmium nitrate, 0.100 part of chromium nitrate, 0.220 part of barium nitrate, 0.120 part of calcium bicarbonate, 0.120 part of nano silicon dioxide and 0.180 part of nano hafnium dioxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate, nano silicon dioxide and nano hafnium dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 8 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1;
step three, adding barium titanate, nano silicon dioxide and hafnium dioxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with the ultrasonic frequency of 40kHz to uniformly disperse the barium titanate, the nano silicon dioxide and the nano hafnium dioxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 5MHz, the temperature of a thermal decomposition chamber is 400 ℃, the sintering temperature is 1100 ℃, and the precursor mixed liquid is atomized, dried, heated by an air heater and sintered to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein the particle size of the nano silicon dioxide and the nano hafnium oxide is less than 50nm, and the particle size of the barium carbonate is less than 300 nm.
Example 3
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant is 100:30: 2, respectively adding the ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 8 hours, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:10:5, and continuing ball milling for 8 hours to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 70, humidifying simultaneously, preserving heat for 1h at 1250 ℃, then cooling to 1000 ℃ for oxygen return with the oxygen content of 20ppm, preserving heat for 2h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 900 ℃, the temperature is kept for 0.5h under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.070 part of vanadyl oxalate, 0.460 part of manganese nitrate, 0.640 part of magnesium nitrate, 1.000 parts of strontium nitrate, 4.620 parts of ytterbium nitrate, 1.510 parts of holmium nitrate, 0.410 part of chromium nitrate, 0.680 part of barium nitrate, 0.420 part of calcium bicarbonate, 0.520 part of nano-silica and 0.500 part of nano-hafnium dioxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate, nano silicon dioxide and nano hafnium dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 6 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 2;
step three, adding barium titanate, nano silicon dioxide and hafnium dioxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with the ultrasonic frequency of 20kHz to uniformly disperse the barium titanate, the nano silicon dioxide and the nano hafnium dioxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 2MHz, the temperature of a thermal decomposition chamber is 600 ℃, the sintering temperature is 800 ℃, and the precursor mixed liquid is subjected to atomization, drying, a hot air blower and sintering to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein the particle size of the nano silicon dioxide and the nano hafnium oxide is less than 50nm, and the particle size of the barium carbonate is less than 300 nm.
Comparative example 1
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:20: 1, respectively adding a ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 5 hours, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:5:10, and continuing ball milling for 5 hours to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 50, humidifying at the same time, preserving heat for 2h at 1220 ℃, then cooling to 900 ℃ for oxygen return with the oxygen content of 12ppm, preserving heat for 4h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 850 ℃, the temperature is kept for 1h under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.307 part of manganese nitrate, 0.318 part of magnesium nitrate, 0.454 part of strontium nitrate, 1.847 parts of ytterbium nitrate, 0.301 part of holmium nitrate, 0.336 part of barium nitrate, 0.208 part of calcium bicarbonate and 0.309 part of nano silicon dioxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate and nano silicon dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 6 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1.5;
step three, adding barium titanate and nano silicon dioxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with the ultrasonic frequency of 30kHz to uniformly disperse the barium titanate and the nano silicon dioxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 4MHz, the temperature of a thermal decomposition chamber is 500 ℃, the sintering temperature is 950 ℃, and the precursor mixed liquid is atomized, dried, heated by an air heater and sintered to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein the particle size of the nano silicon dioxide is less than 50nm, and the particle size of the barium carbonate is less than 300 nm.
Comparative example 2
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:20: 1, respectively adding a ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 5 hours, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:5:10, and continuing ball milling for 5 hours to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 50, humidifying at the same time, preserving heat for 2h at 1220 ℃, then cooling to 900 ℃ for oxygen return with the oxygen content of 12ppm, preserving heat for 4h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 850 ℃, the temperature is kept for 1h under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.013 part of vanadyl oxalate, 0.153 part of manganese nitrate, 0.127 part of magnesium nitrate, 0616 parts of ytterbium nitrate, 0.149 part of dysprosium nitrate, 0.224 part of barium nitrate, 0.139 part of calcium bicarbonate and 0.129 part of nano-silica.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate and nano silicon dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 6 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1.5;
step three, adding barium titanate and nano silicon dioxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with the ultrasonic frequency of 30kHz to uniformly disperse the barium titanate and the nano silicon dioxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 4MHz, the temperature of a thermal decomposition chamber is 500 ℃, the sintering temperature is 950 ℃, and the precursor mixed liquid is atomized, dried, heated by an air heater and sintered to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein the particle size of the nano silicon dioxide is less than 50nm, and the particle size of the barium carbonate is less than 300 nm.
Comparative example 3
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:20: 1, respectively adding a ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 5 hours, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:5:10, and continuing ball milling for 5 hours to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 50, humidifying at the same time, preserving heat for 2h at 1220 ℃, then cooling to 900 ℃ for oxygen return with the oxygen content of 12ppm, preserving heat for 4h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 850 ℃, the temperature is kept for 1h under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.066 part of vanadyl oxalate, 0.460 part of manganese nitrate, 0.636 part of magnesium nitrate, 0.907 part of strontium nitrate, 1.650 parts of yttrium nitrate, 2.155 parts of ytterbium nitrate, 0.448 part of dysprosium nitrate, 0.602 part of holmium nitrate, 0.454 part of erbium nitrate, 0.408 part of chromium nitrate, 0.672 part of barium nitrate, 0.417 part of calcium bicarbonate, 0.515 part of nano-silica and 0.451 part of nano-hafnium dioxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate, nano silicon dioxide and nano hafnium dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 6 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1.5;
step three, adding barium titanate, nano silicon dioxide and hafnium dioxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with ultrasonic frequency of 30kHz to uniformly disperse the barium titanate, the nano silicon dioxide and the nano hafnium dioxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 4MHz, the temperature of a thermal decomposition chamber is 500 ℃, the sintering temperature is 950 ℃, and the precursor mixed liquid is atomized, dried, heated by an air heater and sintered to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein the particle size of the nano silicon dioxide and the nano hafnium oxide is less than 50nm, and the particle size of the barium carbonate is less than 300 nm.
Comparative example 4
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:20: 1, respectively adding a ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 5 hours, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:5:10, and continuing ball milling for 5 hours to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 50, humidifying at the same time, preserving heat for 2h at 1220 ℃, then cooling to 900 ℃ for oxygen return with the oxygen content of 12ppm, preserving heat for 4h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 850 ℃, the temperature is kept for 1h under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.027 part of vanadyl oxalate, 0.307 part of manganese nitrate, 0.318 part of magnesium nitrate, 1.847 parts of ytterbium nitrate, 0.301 part of holmium nitrate, 0.336 part of barium nitrate, 0.208 part of calcium bicarbonate, 0.309 part of nano-silica and 0.271 part of nano-hafnium oxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate, nano silicon dioxide and nano hafnium dioxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 6 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1.5;
step three, adding barium titanate, nano silicon dioxide and hafnium dioxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with ultrasonic frequency of 30kHz to uniformly disperse the barium titanate, the nano silicon dioxide and the nano hafnium dioxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 4MHz, the temperature of a thermal decomposition chamber is 500 ℃, the sintering temperature is 950 ℃, and the precursor mixed liquid is atomized, dried, heated by an air heater and sintered to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein the particle size of the nano silicon dioxide and the nano hafnium oxide is less than 50nm, and the particle size of the barium carbonate is less than 300 nm.
Comparative example 5
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:20: 1, respectively adding a ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 5 hours, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:5:10, and continuing ball milling for 5 hours to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 50, humidifying at the same time, preserving heat for 2h at 1220 ℃, then cooling to 900 ℃ for oxygen return with the oxygen content of 12ppm, preserving heat for 4h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 850 ℃, the temperature is kept for 1h under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.027 part of vanadyl oxalate, 0.307 part of manganese nitrate, 0.318 part of magnesium nitrate, 1.847 parts of ytterbium nitrate, 0.301 part of holmium nitrate, 0.336 part of barium nitrate, 0.208 part of calcium bicarbonate and 0.271 part of nano hafnium dioxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate and nano hafnium oxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 6 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1.5;
step three, adding barium titanate and hafnium oxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with ultrasonic frequency of 30kHz to uniformly disperse the barium titanate and the nano hafnium oxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 4MHz, the temperature of a thermal decomposition chamber is 500 ℃, the sintering temperature is 950 ℃, and the precursor mixed liquid is atomized, dried, heated by an air heater and sintered to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein the grain diameter of the nano hafnium oxide is less than 50nm, and the grain diameter of the barium carbonate is less than 300 nm.
Comparative example 6
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:20: 1, respectively adding a ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 5 hours, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:5:10, and continuing ball milling for 5 hours to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 50, humidifying at the same time, preserving heat for 2h at 1220 ℃, then cooling to 900 ℃ for oxygen return with the oxygen content of 12ppm, preserving heat for 4h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 850 ℃, the temperature is kept for 1h under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.027 part of vanadyl oxalate, 0.307 part of manganese nitrate, 0.318 part of magnesium nitrate, 0.454 part of strontium nitrate, 1.847 parts of ytterbium nitrate, 0.301 part of holmium nitrate, 0.336 part of barium nitrate, 0.208 part of calcium bicarbonate and 0.271 part of nano hafnium oxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate and nano hafnium oxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 6 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1.5;
step three, adding barium titanate and hafnium oxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with ultrasonic frequency of 30kHz to uniformly disperse the barium titanate and the nano hafnium oxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 4MHz, the temperature of a thermal decomposition chamber is 500 ℃, the sintering temperature is 950 ℃, and the precursor mixed liquid is atomized, dried, heated by an air heater and sintered to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein the grain diameter of the nano hafnium oxide is less than 50nm, and the grain diameter of the barium carbonate is less than 300 nm.
Comparative example 7
An anti-reduction BME ceramic dielectric capacitor is prepared by adopting a ceramic material 1 for the anti-reduction BME ceramic dielectric capacitor through the following steps:
step one, refining the porcelain slurry: the ceramic material comprises the following components in percentage by weight: ethanol: toluene: dispersant 100:20: 1, respectively adding a ceramic material, ethanol, toluene and a dispersing agent, ball-milling for 5 hours, and then mixing the ceramic material: dioctyl phthalate: adding dioctyl phthalate and polyvinyl butyral into polyvinyl butyral at a ratio of 100:5:10, and continuing ball milling for 5 hours to obtain casting slurry;
step two, coating: coating the prepared tape-casting slurry into a dielectric layer, wherein the coating thickness is less than or equal to 8 um;
step three, printing: printing the nickel metal inner electrode 2 on the dielectric layer, mutually overlapping the dielectric layer and the dielectric layer, and then performing hydraulic pressure and slicing to manufacture a green body;
step four, degreasing: placing the green body in an air atmosphere at 270 ℃, and preserving heat for 4 hours to degrease;
step five, sintering: sintering in reducing atmosphere while introducing H2/N2Is 1: 50, humidifying at the same time, preserving heat for 2h at 1220 ℃, then cooling to 900 ℃ for oxygen return with the oxygen content of 12ppm, preserving heat for 4h, and cooling to room temperature;
step six, carrying out end attachment: and the end attached external electrode is a copper metal electrode 3, the sintering temperature is 850 ℃, the temperature is kept for 1h under the protection of nitrogen, and the BME ceramic dielectric capacitor is obtained after cooling.
The adopted ceramic material for the anti-reduction BME ceramic dielectric capacitor is composed of the following raw materials in parts by weight: 100 parts of barium titanate, 0.027 part of vanadyl oxalate, 0.307 part of manganese nitrate, 0.318 part of magnesium nitrate, 1.847 parts of ytterbium nitrate, 0.301 part of holmium nitrate, 0.204 part of chromium nitrate, 0.336 part of barium nitrate, 0.208 part of calcium bicarbonate and 0.271 part of nano hafnium dioxide.
The preparation method comprises the following steps:
weighing and mixing raw materials except barium titanate and nano hafnium oxide in the ceramic material for the anti-reduction BME ceramic capacitor according to the proportion to obtain a soluble salt additive;
step two, adding deionized water into the soluble salt additive obtained in the step one, and stirring for 6 hours to completely dissolve the additive, wherein the weight ratio of the soluble salt additive to the deionized water is 1: 1.5;
step three, adding barium titanate and hafnium oxide into the solution obtained in the step two, carrying out nodular stirring for 2 hours, and simultaneously carrying out ultrasonic dispersion with ultrasonic frequency of 30kHz to uniformly disperse the barium titanate and the nano hafnium oxide in the solution to form precursor mixed solution;
and step four, carrying out ultrasonic spray thermal decomposition granulation on the precursor mixed liquid prepared in the step three, wherein the working frequency of an ultrasonic atomizer is 4MHz, the temperature of a thermal decomposition chamber is 500 ℃, the sintering temperature is 950 ℃, and the precursor mixed liquid is atomized, dried, heated by an air heater and sintered to form powder in which nano-scale oxides are uniformly dispersed on barium titanate particles, so that the ceramic material for the anti-reduction BME ceramic is obtained.
Wherein the grain diameter of the nano hafnium oxide is less than 50nm, and the grain diameter of the barium carbonate is less than 300 nm.
The samples prepared in example 1 and comparative examples 1-7 were tested to obtain the following data, the results of which are shown in the following table:
TABLE 1 test parameters for each sample
According to the table, the ceramic material for the anti-reduction BME ceramic dielectric capacitor reduces loss, improves insulation resistance, improves dielectric withstand voltage and obtains good electrical property by adding additives such as vanadyl oxalate, barium nitrate, calcium bicarbonate, nano silicon dioxide, nano hafnium dioxide and the like; wherein, the strontium nitrate is added to be matched with the manganese nitrate and the calcium bicarbonate, so that the oxygen vacancy of the material can be reduced in the sintering process, the reducing resistance of the material is improved, and the loss is reduced; the nano hafnium oxide is added to be matched with strontium nitrate and chromium nitrate, so that A/B position substitution can be simultaneously carried out on barium titanate, the dielectric constant of a system is improved, the reducibility resistance is further improved, the loss is reduced, meanwhile, the nano hafnium oxide is matched with the nano silicon dioxide, the crystal boundary components and the crystal grain size can be controlled, the insulation resistance and the voltage resistance are improved, and the product reliability is improved.
As can be seen from the comparison of example 1 with comparative examples 2, 4, 5, 6 and 7, by limiting the mutual cooperation between nano hafnium oxide and strontium nitrate, chromium nitrate and nano silicon dioxide, excellent properties of extremely high dielectric constant (3481), extremely low loss (0.7%) and high insulation resistance and high breakdown strength can be obtained.
Comparing the embodiment 1 with the comparative example 1, the method has the advantages that the vanadyl oxalate is added to be matched with the nano silicon dioxide, the nano hafnium dioxide, the strontium nitrate and the chromium nitrate, so that a good shell-core structure is formed during sintering, the dielectric constant is high, the loss is low, the temperature stability is good within the working temperature range (-55-125 ℃), and the requirement of X7R is met; meanwhile, the alloy has good insulation resistance (RC at 25 ℃ is more than 2000 MOmega. muF, RC at 125 ℃ is more than 1000 MOmega. muF) and very high breakdown strength (BDV is more than 90V/mum), can be well matched with a base metal inner electrode, has good reduction resistance, and is suitable for sintering in a reducing atmosphere.
By comparing example 1 with comparative example 3, the present invention can obtain excellent properties of extremely high dielectric constant (3481), extremely low loss (0.7%), high insulation resistance and high breakdown strength by limiting the contents of the components to ensure the mutual matching between the substances.
The above description is only a preferred embodiment of the present invention, and therefore should not be taken as limiting the scope of the invention, which is defined by the appended claims and their equivalents and modifications within the scope of the description.
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