A super-thin BME ceramic dielectric capacitor prepared by step doping and a preparation method thereof

Abstract

The application discloses a kind of step-by-step doping preparation ultra-thin BME ceramic dielectric capacitor and preparation method, and the ultra-thin BME ceramic dielectric capacitor is by dielectric layer and dielectric layer mutual superposition and is fired, the dielectric layer includes dielectric layer and electrode printed on dielectric layer, the dielectric layer includes the following raw materials: coated BSCT main matrix, liquid flux agent;Coated BSCT main matrix includes the following raw materials: BSCT material, magnesium nitrate, manganese acetate, oxovanadium oxalate, rare earth nitrate;Liquid flux agent is by nano copper oxide, tetraethyl orthosilicate, tributyl borate in proportion, targeted doping is carried out by step-by-step doping, and new three-layer structure is formed to obtain good comprehensive performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of capacitor preparation, and particularly relates to an ultrathin BME ceramic dielectric capacitor prepared by step-by-step doping and a preparation method. BACKGROUND

[0002] Multilayer ceramic capacitor (MLCC) is a kind of chip capacitor, and its main functions are bypass, decoupling, filtering and energy storage, etc. With the pursuit of miniaturization of electronic devices, small size and high capacity MLCC has become the mainstream product of capacitor products, and higher requirements for its preparation process and reliability are also put forward.

[0003] The multilayer ceramic capacitor is prepared by using the flow casting-cofiring process. The electrode layer and the dielectric layer are stacked on each other through flow casting, printing and lamination, and then the multilayer ceramic capacitor is prepared through degreasing, sintering and end electrode. In order to reduce the cost, the inner electrode usually adopts base metal such as nickel. Since the base metal will be oxidized when sintered in air atmosphere, it needs to be sintered in a reducing atmosphere. Pure barium titanate material cannot meet the use requirements in terms of temperature stability, dielectric loss and reliability, and barium titanate sintered in a reducing atmosphere will be reduced and semiconducting, resulting in low insulation resistance and poor reliability. Therefore, it is necessary to dope and modify the barium titanate so that the ceramic material has good electrical properties and reliability.

[0004] The biggest challenge of MLCC thinning is how to ensure good electrical properties (high dielectric constant, low loss, temperature stability, high insulation resistance) and reliability (service life) while thinning. The dielectric layer ceramic material in MLCC is the basis for obtaining good performance. With the ultrathinning of the dielectric layer, more targeted material formula design of the ceramic material is needed, and more fine and efficient doping methods are used to obtain uniform and reliable microstructure. Therefore, how to more uniformly and efficiently dope to obtain ceramic materials with high dielectric constant, low loss, good temperature stability, high insulation resistance, high reliability and other excellent properties, and to be applied to base metal, ultrathin dielectric layer, large capacity multilayer ceramic capacitor 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 an ultrathin BME ceramic dielectric capacitor prepared by step-by-step doping, and another purpose is to provide a method for preparing the above-mentioned ceramic dielectric capacitor.

[0006] The application adopts the following technical solutions:

[0007] The application discloses a kind of step-by-step doping preparation's ultra-thin BME ceramic dielectric capacitor, by dielectric layer and dielectric layer each other superimposed and fired, the dielectric layer includes dielectric layer and electrode printed on dielectric layer, the dielectric layer includes the following weight parts of raw materials:100 parts of coated BSCT main body, 0.2-2.2 parts of liquid sintering aid;

[0008] The coated BSCT main body includes the following weight parts of raw materials: 100 parts of BSCT material, 0.064-0.636 parts of magnesium nitrate, 0.037-0.371 parts of manganese acetate, 0.007-0.133 parts of vanadyl oxalate, and 0.118-1.221 parts of rare earth nitrate;

[0009] The liquid sintering aid is composed of nano-copper oxide, tetraethyl orthosilicate, and tributyl borate in a weight ratio of 0.03-0.18:0.08-0.90:0.09-1.00.

[0010] Further, the BSCT material is made of barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide in a molar ratio of 98-99.8:0.2-2:0.3-3:97-99.7.

[0011] Further, the rare earth nitrate is one or more of dysprosium nitrate, holmium nitrate, erbium nitrate, yttrium nitrate, and ytterbium nitrate.

[0012] Further, the nano-copper oxide has a particle size of less than 50 um.

[0013] A preparation method of the ultra-thin BME ceramic dielectric capacitor prepared by step-by-step doping, comprising the following steps:

[0014] Step one, synthesizing BSCT material by solid-phase method;

[0015] Step two, synthesizing coated BSCT main body by coprecipitation method: grinding BSCT material in deionized water for 2-12 hours, then adding magnesium nitrate, manganese acetate, vanadyl oxalate, and rare earth nitrate according to the proportion, fully stirring and dissolving, then adding ammonia water into the slurry, adjusting the pH to 9.0-10.0, stirring for 30 minutes-60 minutes, then drying and crushing the slurry to obtain precipitate, and calcining the precipitate at 400°C-600°C to obtain the coated BSCT main body after crushing;

[0016] Step three, preparing liquid sintering aid: stirring and mixing nano-copper oxide, tetraethyl orthosilicate, and tributyl borate according to the proportion, then grinding for 2-12 hours, and filtering to obtain the liquid sintering aid;

[0017] Step four, the preparation of the flowable slurry: add ethanol, toluene, dispersant, liquid flux into the sand mill, then add the coated BSCT main body, grind for 2-6h to uniformly disperse the powder; then add dioctyl phthalate and polyvinyl butyral resin according to the weight ratio, stir for 2-12h, ball mill for 2-12h, filter, defoam to obtain the flowable slurry; wherein the weight ratio of the coated BSCT main body: ethanol: toluene: dispersant: liquid flux = 100: 15-35: 15-35: 0.5-2: 0.2-2.2, and the weight ratio of the coated BSCT main body: dioctyl phthalate: polyvinyl butyral resin = 100: 1-5: 8-12;

[0018] Step five, the manufacture of the green body: flow the slurry into a medium layer with a flowable thickness of 1-5μm, then print the nickel electrode slurry onto the medium layer to form a dielectric layer, and stack the dielectric layer with the dielectric layer, and then perform water pressure and slicing to manufacture the green body;

[0019] Step six, the green body is subjected to debinding, sintering and end attachment to obtain the ultra-thin BME ceramic dielectric capacitor.

[0020] Further, step one specifically comprises: preparing barium carbonate, strontium carbonate, calcium carbonate and titanium dioxide according to the ratio, sand milling with zirconia balls as the grinding medium and deionized water as the dispersion medium, sand milling for 2-12h, then drying, crushing, sieving and synthesizing by the solid phase method at a synthesis temperature of 900-1100℃ for 1-4h to obtain the BSCT material.

[0021] Further, in step six, the sintering specifically comprises: sintering the debound green body in a reducing atmosphere, introducing H2 / N2 and humidifying during the sintering process, heating at a rate of 10-50℃ / min to 1100-1300℃ and maintaining for 0.5-2h; then oxygenating at 800-1000℃ with an oxygen content of 5-100ppm for 1-6h.

[0022] Further, in step six, the end attachment specifically comprises: chamfering the sintered green body and end attaching with a copper electrode at a temperature of 750-950℃ under nitrogen protection for 0.5-2h, and obtaining the ultra-thin BME ceramic dielectric capacitor after cooling.

[0023] Further, in step six, the debinding environment of the green body is 270-350℃ under a nitrogen atmosphere for 6-30h.

[0024] From the above description of the present application, compared with the prior art, the beneficial effects of the present application are:

[0025] Firstly, the application uses raw material composition and preparation method of the porcelain dielectric capacitor, so that the prepared porcelain dielectric capacitor has excellent performances such as extremely high dielectric constant (≥3000), smooth dielectric temperature characteristic curve (X5R requirement), low loss (≤5%), high insulation resistance (RC@25℃≥5000MΩ·μF), high voltage resistance (BDV≥200V) and high reliability (MTTF@48V 85℃≥250h);

[0026] Secondly, the BSCT material is used as the base material to improve the basic performance of the ceramic material; Sr and Ca elements are doped in the barium titanate crystal, targeted A+B site doping is carried out, compared with the traditional barium titanate, the BSCT material doped with Sr and Ca elements has a more stable capacitance temperature curve due to the distortion of the crystal lattice structure, and is less likely to produce oxygen vacancies under a reducing atmosphere, so that the BSCT material has higher insulation resistance and better reliability;

[0027] Thirdly, the liquid phase sintering aid is used, which has excellent sintering effect; the three kinds of sintering aids, namely nano copper oxide, tetraethyl orthosilicate and tributyl borate, are matched to prepare the liquid phase sintering aid, compared with the traditional solid phase sintering aid, the liquid phase sintering aid can form more uniform wrapping on the solid phase particles, so that a more uniform and dense microstructure is obtained during sintering; the nano copper oxide is added in the liquid phase sintering aid, the nano copper oxide particles can fill the gaps between the main matrix particles to prevent the generation of sintering holes, so that the voltage resistance performance of the capacitor can be effectively improved; the tributyl borate is added in the liquid phase sintering aid, which is matched with the tetraethyl orthosilicate, so that the sintering temperature can be effectively reduced, the capacitance temperature stability can be obtained, and the adverse effects of the addition of the sintering aid on the reliability can be avoided;

[0028] Fourthly, the three-step doping preparation method is used to realize targeted formula and structure design, so that the crystal grains present a new three-layer structure different from the traditional structure. Firstly, the Sr and Ca elements are doped in the base body by the solid phase synthesis method, which is used as the "core" layer of the ceramic crystal grains, so that better basic performance than the traditional barium titanate is obtained; secondly, the BSCT material is coated and doped by the coprecipitation method, the Mg, Mn, V and rare earth elements are coated on the surface of the BSCT material to form the intermediate "shell" layer, so that the required capacitance temperature characteristic is obtained, and the grain boundary resistance and reliability are improved; finally, the liquid phase coating is performed on the main matrix particles by the doping form of the liquid phase sintering aid, so that the outer "shell" layer of the third layer structure composed of CuO, SiO2 and B2O3 is formed during sintering, the uniformity of the microstructure is effectively improved, and the voltage resistance performance and reliability are improved. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is an internal structure schematic diagram of the porcelain dielectric capacitor of the application.

[0030] Figure 2 The dielectric constant of the sample of Example 1 varies with temperature;

[0031] Figure 3 The rate of change of the capacitance of the sample of Example 1 varies with temperature;

[0032] In the figure, 1 - dielectric layer, 2 - nickel metal inner electrode, 3 - copper metal electrode. DETAILED DESCRIPTION

[0033] The application is further described below through specific embodiments.

[0034] An ultrathin BME ceramic dielectric capacitor prepared by stepwise doping, which is prepared by firing dielectric layers on each other, specifically, referring to Figure 1 The dielectric layer comprises a dielectric layer and an electrode printed on the dielectric layer.

[0035] The dielectric layer comprises the following raw materials in parts by weight: 100 parts of a coated BSCT main body, 0.2-2.2 parts of a liquid sintering aid.

[0036] The coated BSCT main body comprises the following raw materials in parts by weight: 100 parts of BSCT material, 0.064-0.636 parts of magnesium nitrate, 0.037-0.371 parts of manganese acetate, 0.007-0.133 parts of vanadyl oxalate, and 0.118-1.221 parts of rare earth nitrate.

[0037] The BSCT material is made of barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide in a molar ratio of 98-99.8:0.2-2:0.3-3:97-99.7.

[0038] The rare earth nitrate is one or more of dysprosium nitrate, holmium nitrate, erbium nitrate, yttrium nitrate, and ytterbium nitrate.

[0039] The liquid sintering aid is composed of nano-copper oxide, tetraethyl orthosilicate, and tributyl borate in a weight ratio of 0.03-0.18:0.08-0.90:0.09-1.00, specifically, the particle size of the nano-copper oxide is less than 50 um.

[0040] A preparation method of an ultrathin BME ceramic dielectric capacitor prepared by stepwise doping, comprising the following steps:

[0041] Step one, synthesizing BSCT material by solid phase method: preparing barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide according to the ratio, sanding with zirconia balls as grinding medium and deionized water as dispersion medium, sanding for 2-12 h, then drying, crushing, and sieving, synthesizing by solid phase method at a temperature of 900-1100℃ for 1-4 h, to obtain BSCT material.

[0042] Step two, synthesis of coated BSCT main matrix by co-precipitation method: BSCT material is sand milled in deionized water for 2-12h, then magnesium nitrate, manganese acetate, vanadyl oxalate, and rare earth nitrate are added according to the ratio, and after fully stirring and dissolving, ammonia water is added dropwise to the slurry, and the pH is adjusted to 9.0-10.0, and after stirring for 30min-60min, the slurry is dried and crushed to obtain a precipitate, and the precipitate is calcined at 400℃-600℃, and after crushing, the coated BSCT main matrix is obtained;

[0043] Step three, preparation of liquid sintering aid: nano-copper oxide, tetraethyl orthosilicate, and tributyl borate are stirred and mixed according to the ratio, then sand milled for 2-12h, and filtered to obtain the liquid sintering aid;

[0044] Step four, preparation of casting slurry: ethanol, toluene, dispersant, and liquid sintering aid are added to a sand mill, then the coated BSCT main matrix is added, and ground for 2-6h to disperse the powder uniformly; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirred for 2-12h, ball milled for 2-12h, filtered and defoamed to obtain the casting slurry; wherein the weight ratio of the coated BSCT main matrix: ethanol: toluene: dispersant: liquid sintering aid is 100:15-35:15-35:0.5-2:0.2-2.2, and the weight ratio of the coated BSCT main matrix: dioctyl phthalate: polyvinyl butyral resin is 100:1-5:8-12;

[0045] Step five, green body manufacturing: the slurry is cast into a medium layer with a casting thickness of 1-5μm, then nickel electrode slurry is printed onto the medium layer to form a dielectric layer, and the dielectric layer and the dielectric layer are stacked on each other, and then water pressure and slicing are performed to manufacture the green body;

[0046] Step six, debinding: the green body is debound in an environment of 270-350℃ under a nitrogen atmosphere for 6-30h;

[0047] Step seven, sintering: the debound green body is sintered in a reducing atmosphere, H2 / N2 is introduced during sintering, and the temperature is increased to 1100-1300℃ at a rate of 10-50℃ / min, and the temperature is maintained for 0.5-2h; then the oxygen is returned at 800-1000℃, the oxygen content is 5-100ppm, and the temperature is maintained for 1-6h;

[0048] Step eight, end attachment: the sintered green body is chamfered, and copper electrode end attachment is performed, the attachment temperature is 750-950℃, nitrogen protection is used, the temperature is maintained for 0.5-2h, and after cooling, the ultra-thin BME ceramic dielectric capacitor is obtained.

[0049] Example 1

[0050] The application discloses a super-thin BME ceramic dielectric capacitor prepared by step-by-step doping, which is prepared by stacking and sintering dielectric layers.

[0051] The dielectric layer comprises the following raw materials in parts by weight: 100 parts of a coated BSCT main body and 1.042 parts of a liquid sintering aid.

[0052] The coated BSCT main body comprises the following raw materials in parts by weight: 100 parts of BSCT material, 0.318 parts of magnesium nitrate, 0.185 parts of manganese acetate, 0.066 parts of vanadyl oxalate, 0.299 parts of dysprosium nitrate and 0.462 parts of ytterbium nitrate.

[0053] The BSCT material is prepared from barium carbonate, strontium carbonate, calcium carbonate and titanium dioxide in a molar ratio of 99.0:1.0:1.5:98.5.

[0054] The liquid sintering aid is composed of nano copper oxide, tetraethyl orthosilicate and tributyl borate in a weight ratio of 0.102:0.447:0.493.

[0055] The application discloses a preparation method of a super-thin BME ceramic dielectric capacitor prepared by step-by-step doping.

[0056] Step one: synthesizing BSCT material by a solid-phase method: barium carbonate, strontium carbonate, calcium carbonate and titanium dioxide are prepared according to a proportion, sand grinding is performed on the prepared materials by taking zirconia balls as grinding medium and deionized water as dispersion medium, the sand grinding is performed for 6 hours, and then drying, crushing and sieving are performed, the BSCT material is synthesized by a solid-phase method, the synthesizing temperature is 950 DEG C, and the holding time is 2 hours.

[0057] Step two: synthesizing a coated BSCT main body by a co-precipitation method: the BSCT material is sand ground in deionized water for 6 hours, then magnesium nitrate, manganese acetate, vanadyl oxalate and rare earth nitrate are added according to a proportion, the slurry is fully stirred and dissolved, ammonia water is added dropwise into the slurry, the pH is adjusted to 9.5, the slurry is stirred for 40 minutes, the slurry is dried and crushed to obtain a precipitate, and the precipitate is calcined at 450 DEG C, and then crushed to obtain the coated BSCT main body.

[0058] Step three: preparing a liquid sintering aid: nano copper oxide, tetraethyl orthosilicate and tributyl borate are stirred and mixed according to a proportion, sand grinding is performed for 6 hours, and then the liquid sintering aid is obtained by filtering.

[0059] Step four, preparation of the casting slurry: ethanol, toluene, dispersant, liquid flux were added into a sand mill, then the coated BSCT main body was added and ground for 3h to uniformly disperse the powder; then dioctyl phthalate and polyvinyl butyral resin were added according to the weight ratio, stirred for 4h, ball milled for 5h, filtered and defoamed to obtain the casting slurry; wherein the weight ratio of the coated BSCT main body: ethanol: toluene: dispersant: liquid flux = 100:20:20:1:1.042, and the weight ratio of the coated BSCT main body: dioctyl phthalate: polyvinyl butyral resin = 100:3:10.

[0060] Step five, green body manufacturing: the slurry was cast into a medium layer with a casting thickness of 3μm, then a nickel electrode slurry was printed onto the medium layer to form a dielectric layer, and the dielectric layer and the dielectric layer were stacked on each other, and then water pressure and slicing were performed to manufacture a green body;

[0061] Step six, debinding: the green body was debound in a nitrogen atmosphere at 320℃ for 10h;

[0062] Step seven, sintering: the debound green body was sintered in a reducing atmosphere, H2 / N2(1:100) was introduced during sintering, and the temperature was increased to 1200℃ at a rate of 20℃ / min and kept for 1h; then the oxygen content was returned to 30ppm at 950℃ for 4h;

[0063] Step eight, end attachment: the sintered green body was chamfered, and copper electrode end attachment was performed at a temperature of 850℃ under nitrogen protection for 1h, and after cooling, the ultra-thin BME ceramic dielectric capacitor was obtained.

[0064] Example 2

[0065] An ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping, which is sintered by stacking dielectric layers on each other, specifically, the dielectric layer includes a medium layer and an electrode printed on the medium layer.

[0066] The medium layer includes the following raw materials by weight: 100 parts of a coated BSCT main body, 0.222 parts of a liquid flux.

[0067] The coated BSCT main body includes the following raw materials by weight: 100 parts of BSCT material, 0.064 parts of magnesium nitrate, 0.037 parts of manganese acetate, 0.007 parts of vanadyl oxalate, and 0.118 parts of yttrium nitrate.

[0068] The BSCT material is made of barium carbonate, strontium carbonate, calcium carbonate and titanium dioxide in a molar ratio of 99.8:0.2:0.3:99.7.

[0069] Liquid sintering aid is composed of nano copper oxide, tetraethyl orthosilicate, tributyl borate according to the proportion of 0.034:0.089:0.099.

[0070] A preparation method of an ultra-thin BME ceramic dielectric capacitor prepared by step doping, comprising the following steps:

[0071] Step one, synthesizing BSCT material by solid phase method: according to the proportion, barium carbonate, strontium carbonate, calcium carbonate, titanium dioxide are prepared, zirconium oxide ball is used as grinding medium, deionized water is used as dispersion medium for sand grinding, sand grinding time is 6h, then drying, crushing, sieving, synthesizing by solid phase method, synthesis temperature is 950 DEG C, holding time is 2h, BSCT material is obtained;

[0072] Step two, synthesizing coated BSCT main matrix by coprecipitation method: BSCT material is sand ground in deionized water for 6h, then magnesium nitrate, manganese acetate, vanadyl oxalate, rare earth nitrate are added according to the proportion, after fully stirring and dissolving, ammonia water is added dropwise into the slurry, pH is adjusted to 9.5, after stirring for 40min, the slurry is dried and crushed to obtain the precipitate, and the precipitate is calcined at 450 DEG C, and after crushing, the coated BSCT main matrix is obtained;

[0073] Step three, preparing liquid sintering aid: nano copper oxide, tetraethyl orthosilicate, tributyl borate are stirred and mixed according to the proportion, then sand grinding for 6h, and after filtering, the liquid sintering aid is obtained;

[0074] Step four, preparing casting slurry: ethanol, toluene, dispersant, liquid sintering aid are added into the sand grinder, then the coated BSCT main matrix is added, grinding for 3h, and the powder is uniformly dispersed; then dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, stirring for 4h, ball milling for 5h, filtering and defoaming, and the casting slurry is obtained; wherein the weight ratio of the coated BSCT main matrix, ethanol, toluene, dispersant and liquid sintering aid is 100:20:20:1:0.222, and the weight ratio of the coated BSCT main matrix, dioctyl phthalate and polyvinyl butyral resin is 100:3:10;

[0075] Step five, green body manufacturing: the slurry is cast into a dielectric layer, the casting thickness is 3um, then nickel electrode slurry is printed onto the dielectric layer to form a dielectric layer, and the dielectric layer and the dielectric layer are stacked with each other, and after water pressure and slicing, the green body is manufactured;

[0076] Step six, degreasing: the green body is degreased, and the degreasing environment of the green body is: 320 DEG C, nitrogen atmosphere, and holding for 10h;

[0077] Step seven, sintering: the debound green body is sintered under a reducing atmosphere, H2 / N2(1:100) is introduced during the sintering process, and the temperature is increased to 1200℃ at a rate of 20℃ / min, and the temperature is maintained for 1h; then the oxygen content is 30ppm at 950℃, and the temperature is maintained for 4h;

[0078] Step eight, end attachment: the sintered green body is chamfered, and copper electrodes are attached, the sintering temperature is 850℃, nitrogen protection is used, and the temperature is maintained for 1h, and after cooling, the ultra-thin BME ceramic capacitor is obtained.

[0079] Example 3

[0080] An ultra-thin BME ceramic capacitor prepared by stepwise doping, which is sintered by stacking dielectric layers.

[0081] The dielectric layer includes the following raw materials by weight: 100 parts of coated BSCT main body, 2.051 parts of liquid sintering aid.

[0082] The coated BSCT main body includes the following raw materials by weight: 100 parts of BSCT material, 0.636 parts of magnesium nitrate, 0.371 parts of manganese acetate, 0.133 parts of vanadyl oxalate, 0.451 parts of holmium nitrate, and 0.770 parts of ytterbium nitrate.

[0083] The BSCT material is made of barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide in a molar ratio of 98:2:3.0:97.0.

[0084] The liquid sintering aid is composed of nano-copper oxide, tetraethyl orthosilicate, and tributyl borate in a weight ratio of 0.171:0.893:0.987.

[0085] A preparation method of an ultra-thin BME ceramic capacitor prepared by stepwise doping, comprising the following steps:

[0086] Step one, synthesis of BSCT material by solid phase method: barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide are prepared according to the ratio, and sanding is performed with zirconia balls as grinding medium and deionized water as dispersion medium, sanding time is 6h, then drying, crushing, and sieving are performed, and the BSCT material is synthesized by solid phase method, the synthesis temperature is 950℃, and the holding time is 2h.

[0087] Step two, synthesis of coated BSCT main matrix by co-precipitation method: BSCT material was sand-milled in deionized water for 6 h, and then magnesium nitrate, manganese acetate, vanadyl oxalate, and rare earth nitrate were added according to the ratio. After being fully stirred and dissolved, ammonia water was added dropwise into the slurry, and the pH was adjusted to 9.5. After stirring for 40 min, the slurry was dried and crushed to obtain a precipitate, which was calcined at 450℃. After being crushed, the coated BSCT main matrix was obtained.

[0088] Step three, preparation of liquid sintering aid: nano-copper oxide, tetraethyl orthosilicate, and tributyl borate were stirred and mixed according to the ratio, and then sand-milling was performed for 6 h. The liquid sintering aid was obtained after filtration.

[0089] Step four, preparation of casting slurry: ethanol, toluene, dispersant, and liquid sintering aid were added to a sand mill, followed by the addition of coated BSCT main matrix. The powder was uniformly dispersed after grinding for 3 h. Then, dioctyl phthalate and polyvinyl butyral resin were added according to the weight ratio, and stirring was performed for 4 h. Ball milling was performed for 5 h, and the casting slurry was obtained after filtration and defoaming. The weight ratio of coated BSCT main matrix: ethanol: toluene: dispersant: liquid sintering aid was 100:20:20:1:2.051, and the weight ratio of coated BSCT main matrix: dioctyl phthalate: polyvinyl butyral resin was 100:3:10.

[0090] Step five, green body manufacturing: the slurry was cast into a dielectric layer with a thickness of 3 μm. Then, nickel electrode slurry was printed onto the dielectric layer to form a dielectric layer. The dielectric layer and the dielectric layer were stacked on each other, and the green body was manufactured after water pressure and slicing.

[0091] Step six, debinding: the green body was debound in a nitrogen atmosphere at 320℃ for 10 h.

[0092] Step seven, sintering: the debound green body was sintered in a reducing atmosphere. H2 / N2(1:100) was introduced during sintering, and the temperature was increased to 1200℃ at a rate of 20℃ / min and maintained for 1 h. Then, the oxygen content was returned to 30 ppm at 950℃ for 4 h.

[0093] Step eight, end attachment: the sintered green body was chamfered, and copper electrode end attachment was performed at a temperature of 850℃ under nitrogen protection for 1 h. After cooling, the ultra-thin BME ceramic dielectric capacitor was obtained.

[0094] Comparative Example 1

[0095] An ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping, which is sintered by stacking dielectric layers on each other. The dielectric layer includes a dielectric layer and an electrode printed on the dielectric layer.

[0096] The medium layer comprises the following raw materials: 100 parts of a coated BT main body and 1.042 parts of a liquid sintering aid.

[0097] The coated BT main body is made of the following raw materials by weight: 100 parts of BT material, 0.318 parts of magnesium nitrate, 0.185 parts of manganese acetate, 0.066 parts of vanadyl oxalate, 0.299 parts of dysprosium nitrate, and 0.462 parts of ytterbium nitrate.

[0098] The BT material is made of barium carbonate and titanium dioxide in a molar ratio of 100:100.

[0099] The liquid sintering aid is made of nano-copper oxide, tetraethyl orthosilicate, and tributyl borate in a weight ratio of 0.102:0.447:0.493.

[0100] A preparation method of an ultra-thin BME ceramic dielectric capacitor prepared by step-by-step doping, comprising the following steps:

[0101] Step one: synthesizing BT material by solid phase method: prepare barium carbonate and titanium dioxide according to the proportion, sand mill with zirconia balls as grinding medium and deionized water as dispersion medium for 6 hours, then dry, crush, and sieve, synthesize by solid phase method at a temperature of 950℃ for 2 hours to obtain BT material;

[0102] Step two: synthesizing coated BT main body by co-precipitation method: sand mill BT material in deionized water for 6 hours, then add magnesium nitrate, manganese acetate, vanadyl oxalate, and rare earth nitrate according to the proportion, fully stir and dissolve, then add ammonia water to the slurry, adjust the PH to 9.5, stir for 40 minutes, dry and crush the slurry to obtain precipitate, and calcine the precipitate at 450℃ to obtain coated BT main body after crushing;

[0103] Step three: prepare liquid sintering aid: mix nano-copper oxide, tetraethyl orthosilicate, and tributyl borate according to the proportion, sand mill for 6 hours, and filter to obtain liquid sintering aid;

[0104] Step four: prepare casting slurry: add ethanol, toluene, dispersant, and liquid sintering aid into a sand mill, then add coated BT main body, wherein the weight ratio of coated BT main body: ethanol: toluene: dispersant: liquid sintering aid is 100:20:20:1:1.042, grind for 3 hours to uniformly disperse the powder; then add dioctyl phthalate and polyvinyl butyral resin according to the weight ratio, wherein the weight ratio of coated BSCT main body: dioctyl phthalate: polyvinyl butyral resin is 100:3:10, stir for 4 hours, ball mill for 5 hours, filter, and defoam to obtain casting slurry;

[0105] Step five, green body manufacturing: the slurry is cast into a medium layer with a casting thickness of 3 μm, then a nickel electrode slurry is printed on the medium layer to form a dielectric layer, and the dielectric layer is stacked with the dielectric layer, and the green body is manufactured through water pressure and slicing;

[0106] Step six, debinding: the green body is debound under the condition of 320 DEG C and nitrogen atmosphere for 10 h;

[0107] Step seven, sintering: the debound green body is sintered under a reducing atmosphere, H2 / N2 (1:100) is introduced during sintering, and the temperature is increased to 1200 DEG C at a rate of 20 DEG C / min and kept for 1 h; then the oxygen content is 30 ppm at 950 DEG C, and the temperature is kept for 4 h;

[0108] Step eight, end attachment: the sintered green body is chamfered, and copper electrode end attachment is adopted, the sintering temperature is 850 DEG C, nitrogen protection is adopted, and the temperature is kept for 1 h, and the ultra-thin BME ceramic dielectric capacitor prepared by step-by-step doping is obtained after cooling.

[0109] Comparative example 2

[0110] An ultra-thin BME ceramic dielectric capacitor prepared by step-by-step doping is sintered by stacking a dielectric layer with a dielectric layer, and the dielectric layer comprises a medium layer and an electrode printed on the medium layer.

[0111] The medium layer comprises the following raw materials: 100 parts of a coated BCT main body and 1.042 parts of a liquid sintering aid.

[0112] The coated BCT main body is made of the following raw materials by weight: 100 parts of BCT material, 0.318 parts of magnesium nitrate, 0.185 parts of manganese acetate, 0.066 parts of vanadyl oxalate, 0.299 parts of dysprosium nitrate, and 0.462 parts of ytterbium nitrate.

[0113] The BCT material is made of barium carbonate, calcium carbonate, and titanium dioxide in a molar ratio of 100:1.5:98.5.

[0114] The liquid sintering aid is made of nano-copper oxide, tetraethyl orthosilicate, and tributyl borate in a weight ratio of 0.102:0.447:0.493.

[0115] A preparation method of an ultra-thin BME ceramic dielectric capacitor prepared by step-by-step doping comprises the following steps:

[0116] Step one, synthesis of BCT material by solid phase method: barium carbonate, calcium carbonate, and titanium dioxide are prepared according to the ratio, sand grinding is performed with zirconia balls as grinding medium and deionized water as dispersion medium, the sand grinding time is 6 h, then drying, crushing, and sieving are performed, and the BCT material is synthesized by solid phase method at a synthesis temperature of 950 DEG C for 2 h.

[0117] Step two, synthesis of coated BCT main matrix by co-precipitation method: the BCT material was sand-milled in deionized water for 6h, then magnesium nitrate, manganese acetate, vanadyl oxalate, and rare earth nitrate were added according to the ratio, and after fully stirring and dissolving, ammonia water was added dropwise to the slurry, and the PH was adjusted to 9.5, and after stirring for 40min, the slurry was dried and crushed to obtain the precipitate, and the precipitate was calcined at 450℃, and after crushing, the coated BCT main matrix was obtained;

[0118] Step three, preparation of liquid sintering aid: nano copper oxide, tetraethyl orthosilicate, and tributyl borate were stirred and mixed according to the ratio, then sand-milling was performed for 6h, and the liquid sintering aid was obtained after filtration;

[0119] Step four, preparation of casting slurry: ethanol, toluene, dispersant, and liquid sintering aid were added to a sand mill, then the coated BCT main matrix was added, and the weight ratio of the coated BCT main matrix: ethanol: toluene: dispersant: liquid sintering aid was 100:20:20:1:1.042, the powder was uniformly dispersed after grinding for 3h; then dioctyl phthalate and polyvinyl butyral resin were added according to the weight ratio, and the weight ratio of the coated BCT main matrix: dioctyl phthalate: polyvinyl butyral resin was 100:3:10, stirring was performed for 4h, and ball milling was performed for 5h, then filtration and defoaming were performed to obtain the casting slurry;

[0120] Step five, green body manufacturing: the slurry was cast into a medium layer with a casting thickness of 3μm, then nickel electrode slurry was printed onto the medium layer to form a dielectric layer, and the dielectric layer and the dielectric layer were stacked on each other, and then water pressure and slicing were performed to manufacture the green body;

[0121] Step six, debinding: the green body was debound under the conditions of 320℃ and nitrogen atmosphere for 10h;

[0122] Step seven, sintering: the debound green body was sintered in a reducing atmosphere, H2 / N2(1:100) was introduced during sintering, and the temperature was increased to 1200℃ at a rate of 20℃ / min and kept for 1h; then the oxygen content was returned to 30ppm at 950℃ for 4h;

[0123] Step eight, end attachment: the sintered green body was chamfered, and copper electrode end attachment was performed at a temperature of 850℃ under nitrogen protection for 1h, and after cooling, the ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping was obtained.

[0124] Comparative Example 3

[0125] An ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping is formed by stacking dielectric layers on each other, and the dielectric layer includes a medium layer and an electrode printed on the medium layer.

[0126] The medium layer comprises the following raw materials: 100 parts of a coated BST main body and 1.042 parts of a liquid sintering aid.

[0127] The coated BST main body is made of the following raw materials by weight: 100 parts of BST material, 0.318 parts of magnesium nitrate, 0.185 parts of manganese acetate, 0.066 parts of vanadyl oxalate, 0.299 parts of dysprosium nitrate, and 0.462 parts of ytterbium nitrate.

[0128] The BST material is made of barium carbonate, strontium carbonate, and titanium dioxide in a molar ratio of 99.0:1.0:100.

[0129] The liquid sintering aid is made of nano-copper oxide, tetraethyl orthosilicate, and tributyl borate in a weight ratio of 0.102:0.447:0.493.

[0130] A preparation method of an ultrathin BME ceramic dielectric capacitor prepared by stepwise doping, comprising the following steps:

[0131] Step one, synthesis of BST material by solid phase method: prepare barium carbonate, strontium carbonate, and titanium dioxide according to the proportion, sand mill with zirconia balls as grinding medium and deionized water as dispersion medium for 6h, then dry, crush, and sieve, synthesize by solid phase method at a synthesis temperature of 950℃ for 2h to obtain the BST material;

[0132] Step two, synthesis of coated BST main body by co-precipitation method: sand mill the BST material in deionized water for 6h, then add magnesium nitrate, manganese acetate, vanadyl oxalate, and rare earth nitrate according to the proportion, fully stir and dissolve, then add ammonia water to the slurry, adjust the PH to 9.5, stir for 40min, dry and crush the slurry to obtain the precipitate, and calcine the precipitate at 450℃ to obtain the coated BST main body after crushing;

[0133] Step three, preparation of liquid sintering aid: mix nano-copper oxide, tetraethyl orthosilicate, and tributyl borate according to the proportion, sand mill for 6h, and filter to obtain the liquid sintering aid;

[0134] Step four, preparation of the casting slurry: ethanol, toluene, dispersant, liquid flux were added into a sand mill, then the coated BST main matrix was added, wherein the weight ratio of the coated BST main matrix: ethanol: toluene: dispersant: liquid flux = 100:20:20:1:1.042, and the powder was uniformly dispersed by grinding for 3h; then dioctyl phthalate and polyvinyl butyral resin were added according to the weight ratio of the coated BST main matrix: dioctyl phthalate: polyvinyl butyral resin = 100:3:10, and stirring was performed for 4h and ball milling was performed for 5h, and then filtration and defoaming were performed to obtain the casting slurry;

[0135] Step five, green body manufacturing: the slurry was cast into a medium layer with a casting thickness of 3μm, then a nickel electrode slurry was printed onto the medium layer to form a dielectric layer, and the dielectric layer and the dielectric layer were stacked with each other, and then water pressure and slicing were performed to manufacture the green body;

[0136] Step six, debinding: the green body was debound under the condition of 320℃ and nitrogen atmosphere for 10h;

[0137] Step seven, sintering: the debound green body was sintered under a reducing atmosphere, H2 / N2(1:100) was introduced during sintering, and the temperature was increased to 1200℃ at a rate of 20℃ / min and was kept for 1h; then the oxygen content was returned to 30ppm at 950℃ for 4h;

[0138] Step eight, end attachment: the sintered green body was chamfered, and copper electrode end attachment was performed, the sintering temperature was 850℃, nitrogen protection was adopted, and the temperature was kept for 1h, and then the ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping was obtained after cooling.

[0139] Comparative Example 4

[0140] An ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping is sintered by stacking a dielectric layer and a dielectric layer with each other, and the dielectric layer comprises a medium layer and an electrode printed on the medium layer.

[0141] The medium layer comprises the following raw materials: 100 parts of a coated BST main matrix and 0.940 parts of a liquid flux.

[0142] The coated BST main matrix is prepared from the following raw materials in parts by weight: 100 parts of a BST material, 0.318 parts of magnesium nitrate, 0.185 parts of manganese acetate, 0.066 parts of vanadyl oxalate, 0.299 parts of dysprosium nitrate, and 0.462 parts of ytterbium nitrate.

[0143] The BST material is prepared from barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide in a molar ratio of 99.0:1.0:1.5:98.5.

[0144] Liquid sintering aid is made of tetraethyl orthosilicate and tributyl borate in a weight ratio of 0.447:0.493.

[0145] A preparation method of an ultra-thin BME ceramic dielectric capacitor prepared by step doping, comprising the following steps:

[0146] Step one, synthesizing BSCT material by solid phase method: preparing barium carbonate, strontium carbonate, calcium carbonate and titanium dioxide according to the proportion, sand grinding with zirconium oxide ball as grinding medium and deionized water as dispersion medium for 6h, then drying, crushing, sieving, synthesizing by solid phase method at a temperature of 950 DEG C for 2h to obtain BSCT material;

[0147] Step two, synthesizing coated BSCT main matrix by coprecipitation method: sand grinding BSCT material in deionized water for 6h, then adding magnesium nitrate, manganese acetate, vanadyl oxalate and rare earth nitrate according to the proportion, fully stirring and dissolving, then adding ammonia water into the slurry, adjusting the PH to 9.5, stirring for 40min, drying and crushing the slurry to obtain precipitate, and calcining the precipitate at 450 DEG C to obtain coated BSCT main matrix;

[0148] Step three, preparing liquid sintering aid: stirring and mixing tetraethyl orthosilicate and tributyl borate according to the proportion, sand grinding for 6h, and filtering to obtain liquid sintering aid;

[0149] Step four, preparing casting slurry: adding ethanol, toluene, dispersant and liquid sintering aid into a sand grinder, then adding coated BSCT main matrix, wherein the weight ratio of coated BSCT main matrix: ethanol: toluene: dispersant: liquid sintering aid is 100:20:20:1:0.940, grinding for 3h to uniformly disperse the powder, then adding dioctyl phthalate and polyvinyl butyral resin according to the weight ratio of coated BSCT main matrix: dioctyl phthalate: polyvinyl butyral resin = 100:3:10, stirring for 4h, ball milling for 5h, filtering and defoaming to obtain casting slurry;

[0150] Step five, green body manufacturing: casting the slurry into a dielectric layer with a casting thickness of 3um, then printing nickel electrode slurry onto the dielectric layer to form a dielectric layer, and stacking the dielectric layer and the dielectric layer, and then manufacturing a green body through water pressure and slicing;

[0151] Step six, degreasing: degreasing the green body under the condition of 320 DEG C and nitrogen atmosphere for 10h;

[0152] Step seven, sintering: the debound green body is sintered in a reducing atmosphere, H2 / N2(1:100) is introduced during the sintering process, and the temperature is increased to 1200℃ at a rate of 20℃ / min, and the temperature is maintained for 1h; then the oxygen content is 30ppm at 950℃, and the temperature is maintained for 4h;

[0153] Step eight, end attachment: the sintered green body is chamfered, and copper electrodes are attached, the sintering temperature is 850℃, nitrogen protection is used, and the temperature is maintained for 1h, and after cooling, the step-by-step doped ultra-thin BME ceramic capacitor is obtained.

[0154] Comparative example 5

[0155] A step-by-step doped ultra-thin BME ceramic capacitor is prepared, which is sintered by stacking dielectric layers on each other, the dielectric layer includes a dielectric layer and an electrode printed on the dielectric layer.

[0156] The dielectric layer includes the following raw materials: 100 parts of coated BSCT main body, 0.549 parts of liquid sintering aid.

[0157] The coated BSCT main body is made of the following raw materials by weight: BSCT material 100 parts, magnesium nitrate 0.318 parts, manganese acetate 0.185 parts, vanadyl oxalate 0.066 parts, dysprosium nitrate 0.299 parts, ytterbium nitrate 0.462 parts.

[0158] The BSCT material is made of barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide in a molar ratio of 99.0:1.0:1.5:98.5.

[0159] The liquid sintering aid is made of nano copper oxide and tetraethyl orthosilicate in a weight ratio of 0.102:0.447.

[0160] A step-by-step doped ultra-thin BME ceramic capacitor preparation method, comprising the following steps:

[0161] Step one, synthesis of BSCT material by solid phase method: prepare barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide according to the ratio, use zirconia balls as grinding medium and deionized water as dispersion medium for sanding, sanding time is 6h, then dry, crush, sieve, synthesize by solid phase method, synthesis temperature is 950℃, and the temperature is maintained for 2h, to obtain BSCT material;

[0162] Step two, synthesis of coated BSCT main matrix by co-precipitation method: the BSCT material was sand-milled in deionized water for 6 h, and then magnesium nitrate, manganese acetate, vanadyl oxalate, and rare earth nitrate were added according to the ratio. After being fully stirred and dissolved, ammonia water was added dropwise into the slurry, and the pH was adjusted to 9.5. After stirring for 40 min, the slurry was dried and crushed to obtain a precipitate, which was calcined at 450℃. After being crushed, the coated BSCT main matrix was obtained.

[0163] Step three, preparation of liquid sintering aid: nano-copper oxide and tetraethyl orthosilicate were stirred and mixed according to the ratio, and then sand-milled for 6 h. The liquid sintering aid was obtained after filtration.

[0164] Step four, preparation of casting slurry: ethanol, toluene, dispersant, and liquid sintering aid were added to a sand mill, followed by the addition of the coated BSCT main matrix. The weight ratio of the coated BSCT main matrix, ethanol, toluene, dispersant, and liquid sintering aid was 100:20:20:1:0.549. The powder was uniformly dispersed after being ground for 3 h. Then, dioctyl phthalate and polyvinyl butyral resin were added according to the weight ratio of the coated BSCT main matrix, dioctyl phthalate, and polyvinyl butyral resin, which was 100:3:10. The slurry was stirred for 4 h and ball-milled for 5 h. After filtration and defoaming, the casting slurry was obtained.

[0165] Step five, green body manufacturing: the slurry was cast into a dielectric layer with a thickness of 3 μm. Then, a nickel electrode slurry was printed onto the dielectric layer to form a dielectric layer. The dielectric layer and the dielectric layer were stacked on each other, and then water pressure and slicing were performed to manufacture a green body.

[0166] Step six, debinding: the green body was debound under the following conditions: 320℃, nitrogen atmosphere, and 10 h of heat preservation.

[0167] Step seven, sintering: the debound green body was sintered in a reducing atmosphere. During the sintering process, H2 / N2(1:100) was introduced, and the temperature was increased to 1200℃ at a rate of 20℃ / min and maintained for 1 h. Then, the temperature was returned to 950℃ in an oxygen atmosphere with an oxygen content of 30 ppm, and the temperature was maintained for 4 h.

[0168] Step eight, end attachment: the sintered green body was chamfered, and copper electrodes were attached at a temperature of 850℃ under nitrogen protection for 1 h. After cooling, the ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping was obtained.

[0169] Comparative Example 6

[0170] An ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping is formed by stacking a dielectric layer and a dielectric layer. The dielectric layer includes a dielectric layer and an electrode printed on the dielectric layer.

[0171] The medium layer comprises the following raw materials: 100 parts of coated BSCT main body and 0.595 parts of liquid sintering aid.

[0172] The coated BSCT main body is made of the following raw materials by weight: 100 parts of BSCT material, 0.318 parts of magnesium nitrate, 0.185 parts of manganese acetate, 0.066 parts of vanadyl oxalate, 0.299 parts of dysprosium nitrate and 0.462 parts of ytterbium nitrate.

[0173] The BSCT material is made of barium carbonate, strontium carbonate, calcium carbonate and titanium dioxide in a molar ratio of 99.0:1.0:1.5:98.5.

[0174] The liquid sintering aid is made of nano copper oxide and tributyl borate in a weight ratio of 0.102:0.493.

[0175] A preparation method of an ultrathin BME ceramic dielectric capacitor prepared by stepwise doping, comprising the following steps:

[0176] Step one: synthesizing BSCT material by solid phase method: barium carbonate, strontium carbonate, calcium carbonate and titanium dioxide are prepared according to the proportion, and sand milling is performed with zirconia balls as grinding medium and deionized water as dispersion medium for 6 hours, followed by drying, crushing, sieving, synthesizing by solid phase method at a temperature of 950 DEG C for 2 hours to obtain BSCT material;

[0177] Step two: synthesizing coated BSCT main body by coprecipitation method: the BSCT material is sand milled in deionized water for 6 hours, and then magnesium nitrate, manganese acetate, vanadyl oxalate and rare earth nitrate are added according to the proportion, and after being fully stirred and dissolved, ammonia water is added dropwise to the slurry, the PH value is adjusted to 9.5, and the slurry is dried and crushed after stirring for 40 minutes to obtain the precipitate, which is calcined at 450 DEG C, and then crushed to obtain the coated BSCT main body;

[0178] Step three: preparing liquid sintering aid: nano copper oxide and tetraethyl orthosilicate are stirred and mixed according to the proportion, and then sand milling is performed for 6 hours to obtain the liquid sintering aid;

[0179] Step four: preparing casting slurry: ethanol, toluene, dispersant and liquid sintering aid are added into a sand mill, and then the coated BSCT main body is added, wherein the weight ratio of the coated BSCT main body: ethanol: toluene: dispersant: liquid sintering aid is 100:20:20:1:0.595, and the powder is uniformly dispersed after grinding for 3 hours; dioctyl phthalate and polyvinyl butyral resin are added according to the weight ratio, wherein the weight ratio of the coated BSCT main body: dioctyl phthalate: polyvinyl butyral resin is 100:3:10, and stirring is performed for 4 hours, ball milling is performed for 5 hours, and then filtering and defoaming are performed to obtain the casting slurry;

[0180] Step five, green body manufacturing: the slurry is cast into a medium layer with a casting thickness of 3 μm, then a nickel electrode slurry is printed onto the medium layer to form a dielectric layer, and the dielectric layer is stacked with the dielectric layer, and then water pressure and slicing are performed to manufacture a green body;

[0181] Step six, debinding: the green body is debound under the following conditions: 320 DEG C, nitrogen atmosphere, and 10 h of heat preservation;

[0182] Step seven, sintering: the debound green body is sintered in a reducing atmosphere, H2 / N2 (1:100) is introduced during sintering, and the temperature is increased to 1200 DEG C at a rate of 20 DEG C / min and then heat preserved for 1 h; then the oxygen content is returned to 30 ppm at 950 DEG C and heat preserved for 4 h;

[0183] Step eight, end attachment: the sintered green body is chamfered, and copper electrode end attachment is performed at a sintering temperature of 850 DEG C under nitrogen protection, and heat preserved for 1 h, and then cooled to obtain the step-by-step doped ultra-thin BME ceramic dielectric capacitor.

[0184] Comparative Example 7

[0185] A step-by-step doped ultra-thin BME ceramic dielectric capacitor is manufactured by stacking dielectric layers with each other and sintering, and the dielectric layer comprises a medium layer and an electrode printed on the medium layer.

[0186] The medium layer comprises the following raw materials: 100 parts of a coated BSCT main body and 0.102 parts of nano copper oxide.

[0187] The coated BSCT main body is made of the following raw materials by weight: 100 parts of BSCT material, 0.318 parts of magnesium nitrate, 0.185 parts of manganese acetate, 0.066 parts of vanadyl oxalate, 0.299 parts of dysprosium nitrate, and 0.462 parts of ytterbium nitrate.

[0188] The BSCT material is made of barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide in a molar ratio of 99.0:1.0:1.5:98.5.

[0189] A step-by-step doped ultra-thin BME ceramic dielectric capacitor manufacturing method comprises the following steps:

[0190] Step one, synthesis of BSCT material by solid phase method: barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide are prepared according to the ratio, and sand milling is performed with zirconia balls as the grinding medium and deionized water as the dispersion medium, the sand milling time is 6 h, and then drying, crushing, and sieving are performed, and the BSCT material is synthesized by a solid phase method at a synthesis temperature of 950 DEG C and a heat preservation time of 2 h;

[0191] Step two, synthesis of coated BSCT main matrix by co-precipitation method: the BSCT material was sand-milled in deionized water for 6 h, and then magnesium nitrate, manganese acetate, vanadyl oxalate, and rare earth nitrate were added according to the ratio. After being fully stirred and dissolved, ammonia water was added dropwise to the slurry, and the pH was adjusted to 9.5. After stirring for 40 min, the slurry was dried and crushed to obtain a precipitate, which was calcined at 450°C. After crushing, the coated BSCT main matrix was obtained.

[0192] Step three, preparation of casting slurry: ethanol, toluene, dispersant, and liquid sintering aid were added to a sand mill, followed by the addition of the coated BSCT main matrix. The weight ratio of the coated BSCT main matrix: ethanol: toluene: dispersant: nano-copper oxide was 100:20:20:1:0.102, and the powder was ground for 3 h to ensure uniform dispersion. Then, dioctyl phthalate and polyvinyl butyral resin were added according to the weight ratio of 100:3:10. The mixture was stirred for 4 h and ball-milled for 5 h. After filtration and defoaming, the casting slurry was obtained.

[0193] Step four, green body manufacturing: the slurry was cast into a medium layer with a thickness of 3 μm. Then, a nickel electrode slurry was printed onto the medium layer to form a dielectric layer. The dielectric layer and the dielectric layer were stacked on each other, and then water pressure and slicing were performed to manufacture the green body.

[0194] Step five, debinding: the green body was debound under the following conditions: 320°C, nitrogen atmosphere, and 10 h of heat preservation.

[0195] Step six, sintering: the debound green body was sintered in a reducing atmosphere. During the sintering process, H2 / N2(1:100) was introduced, and the temperature was increased to 1200°C at a rate of 20°C / min and maintained for 1 h. Then, the temperature was returned to 950°C in an oxygen atmosphere with an oxygen content of 30 ppm, and the temperature was maintained for 4 h.

[0196] Step seven, end attachment: the sintered green body was chamfered, and copper electrodes were attached at a temperature of 850°C under nitrogen protection for 1 h. After cooling, the ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping was obtained.

[0197] Comparative Example 8

[0198] This comparative example used a one-step doping method of barium titanate to prepare a capacitor. The molar ratio of the added dopant elements was the same as that of Example 1, but the doping method was different.

[0199] The preparation process includes the following steps:

[0200] Step one, solid phase synthesis of BSCT material: according to the proportion, barium carbonate, strontium carbonate, calcium carbonate, titanium dioxide are prepared, zirconium oxide ball is used as grinding medium, deionized water is used as dispersion medium for sand grinding, sand grinding time is 6h, then drying, crushing, sieving, solid phase synthesis, synthesis temperature is 950℃, holding time is 2h, BSCT material is obtained;

[0201] Step two, preparation of casting slurry: ethanol, toluene, dispersing agent are added into sand mill, then BSCT material is added, wherein the weight ratio of BSCT material: ethanol: toluene: dispersing agent is 100:20:20:1, after grinding for 3h, dopant is added according to the molar ratio of BSCT material: magnesium oxide: manganese carbonate: vanadium pentoxide: dysprosium oxide: ytterbium oxide: nano copper oxide: tetraethyl orthosilicate: tributyl borate is 100:0.5:0.25:0.1:0.2:0.3:0.3:0.5:0.5; then dioctyl phthalate, polyvinyl butyral resin are added according to the weight ratio, wherein the weight ratio of coated BSCT main matrix: dioctyl phthalate: polyvinyl butyral resin is 100:3:10, stirring for 4h, ball milling for 5h, filtering, defoaming, obtaining casting slurry;

[0202] Step three, green body manufacturing: the slurry is cast into a medium layer, the casting thickness is 3μm, then nickel electrode slurry is printed on the medium layer to form a dielectric layer, the dielectric layer and the dielectric layer are stacked with each other, and the green body is manufactured after water pressure and slicing;

[0203] Step four, debinding: the green body is debound, and the debinding conditions of the green body are as follows: 320℃, nitrogen atmosphere, holding for 10h;

[0204] Step five, sintering: the debound green body is sintered in a reducing atmosphere, H2 / N2(1:100) is introduced during sintering, and the temperature is increased to 1200℃ at a rate of 20℃ / min and held for 1h; then the oxygen content is 30ppm at 950℃, and the holding time is 4h;

[0205] Step six, end attachment: the sintered green body is chamfered, and copper electrode end attachment is adopted, the sintering temperature is 850℃, nitrogen protection is adopted, and the holding time is 1h, after cooling, the ultra-thin BME ceramic dielectric capacitor prepared by stepwise doping is obtained.

[0206] The capacitors prepared by examples 1-3 and comparative examples 1-8 are tested to obtain the following data, and the results are as follows:

[0207] Table 1 test results of each capacitor

[0208]

[0209] Through the above table and the attached Figure 2 ,3 It can be known that the ultra-thin BME ceramic capacitor prepared by the application adopts a step-by-step doping preparation method, synthesizes BSCT material by a solid phase method, and coats Mg, Mn, V, rare earth elements and the like on the BSCT material, so as to obtain a smooth temperature characteristic curve, high insulation resistance and good reliability; by using the liquid phase sintering agent prepared by nano-copper oxide, tetraethyl orthosilicate and tributyl borate, the sintering temperature is reduced, high dielectric constant, high voltage resistance performance and further improved reliability are obtained.

[0210] It can be known by comparing example 1 with comparative examples 1-7 that by limiting the synthesis of the coated BSCT main matrix and cooperating with the liquid phase sintering agent, very high dielectric constant (≥3000), smooth temperature characteristic curve (complying with the X5R requirement), lower loss (≤5%), high insulation resistance (RC@25℃≥5000MΩ·μF), high voltage resistance (BDV≥200V) and high reliability (MTTF@48V 85℃≥250h) and the like excellent performance can be obtained.

[0211] It can be known by comparing example 1 with comparative example 8 that the solid phase synthesis + coating method + liquid phase sintering method can be targeted step-by-step doping, so as to obtain high K value, smooth TCC, high RC value, high voltage resistance and high reliability, which is due to the step-by-step doping method, so that the doping elements are distributed in different micro areas, and the crystal grains form a new three-layer structure, while the traditional one-step doping method mixes all the dopants together without distinction, and cannot be targeted doping, resulting in poor electrical performance.

[0212] The above is only a preferred embodiment of the application, and therefore cannot limit the range of the application, that is, equivalent changes and modifications made according to the patent range and content of the specification should still be within the scope of the application.

Claims

1. An ultrathin BME ceramic capacitor prepared by step-by-step doping, formed by stacking and firing dielectric layers, wherein the dielectric layers include a dielectric layer and electrodes printed on the dielectric layer, characterized in that: The dielectric layer comprises the following raw materials in parts by weight: 100 parts of the coated BSCT main matrix and 0.2-2.2 parts of a liquid sintering aid; The coated BSCT main matrix includes the following raw materials in parts by weight: 100 parts of BSCT material, 0.064-0.636 parts of magnesium nitrate, 0.037-0.371 parts of manganese acetate, 0.007-0.133 parts of vanadyl oxalate, and 0.118-1.221 parts of rare earth nitrate; The liquid sintering aid is composed of nano copper oxide, ethyl orthosilicate, and tributyl borate in a weight ratio of 0.03-0.18:0.08-0.90:0.09-1.00; The BSCT material is made of barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide in a molar ratio of 98-99.8:0.2-2:0.3-3:97-99.7; The rare earth nitrate is one or more of dysprosium nitrate, holmium nitrate, erbium nitrate, yttrium nitrate and ytterbium nitrate.

2. The ultra-thin BME ceramic capacitor prepared by step-by-step doping according to claim 1, characterized in that: The particle size of the nano copper oxide is less than 50 μm.

3. The method for preparing an ultra-thin BME ceramic capacitor prepared by step-by-step doping according to any one of claims 1 to 2, characterized in that: The following steps are involved: Step 1, synthesizing BSCT material by solid phase method; Step 2: Synthesize the coated BSCT main matrix by co-precipitation method: sand-mill the BSCT material in deionized water for 2-12 hours, then add magnesium nitrate, manganese acetate, vanadyl oxalate, and rare earth nitrate according to the ratio, stir and dissolve thoroughly, then add ammonia water dropwise to the slurry, adjust the pH to 9.0-10.0, stir and react for 30-60 minutes, dry and crush the slurry to obtain a precipitate, and calcine the precipitate at 400-600°C. After crushing, the coated BSCT main matrix is ​​obtained; Step 3: Prepare a liquid sintering aid: Mix nano copper oxide, ethyl orthosilicate, and tributyl borate according to a certain ratio, sand mill for 2-12 hours, and filter to obtain a liquid sintering aid; Step 4, preparation of casting slurry: add ethanol, toluene, dispersant, and liquid sintering agent into a sand mill, then add the coated BSCT main matrix, grind for 2-6 hours, and evenly disperse the powder; then add dioctyl phthalate and polyvinyl butyral resin according to weight ratio, stir for 2-12 hours, ball mill for 2-12 hours, filter, defoam, and obtain casting slurry; wherein, by weight ratio, coated BSCT main matrix: ethanol: toluene: dispersant: liquid sintering agent = 100:15-35:15-35:0.5-2:0.2-2.2, coated BSCT main matrix: dioctyl phthalate: polyvinyl butyral resin = 100:1-5:8-12; Step 5: Green body manufacturing: The slurry is tape-cast into a dielectric layer with a thickness of 1-5 μm. Subsequently, the nickel electrode slurry is printed onto the dielectric layer to form a dielectric layer. The dielectric layers are stacked on each other, and then subjected to water pressing and slicing to manufacture a green body; Step six, degreasing, sintering, and terminal attachment are performed on the green body to obtain the ultra-thin BME ceramic capacitor.

4. The method for preparing an ultra-thin BME ceramic capacitor prepared by step-by-step doping according to claim 3, characterized in that: Step 1 specifically includes: preparing barium carbonate, strontium carbonate, calcium carbonate, and titanium dioxide according to a ratio, sand-milling with zirconium oxide balls as a grinding medium and deionized water as a dispersion medium for 2-12 hours, followed by drying, crushing, and screening, and synthesizing by a solid-phase method at a synthesis temperature of 900-1100°C and a holding time of 1-4 hours to obtain BSCT material.

5. The method for preparing an ultra-thin BME ceramic capacitor prepared by step-by-step doping according to claim 3, characterized in that: In step six, sintering specifically includes: sintering the degreased green body in a reducing atmosphere, introducing H2 / N2 during the sintering process, and humidifying at the same time, heating to 1100-1300℃ at a rate of 10-50℃ / min and keeping warm for 0.5-2h; then back-oxidizing at 800-1000℃, with an oxygen content of 5-100ppm, and keeping warm for 1-6h.

6. The method for preparing an ultra-thin BME ceramic capacitor prepared by step-by-step doping according to claim 3, characterized in that: In step six, the end attachment specifically includes: chamfering the sintered green body and using copper electrode end attachment, the sintering temperature is 750-950°C, using nitrogen protection, keeping the temperature for 0.5-2h, and after cooling, the ultra-thin BME ceramic capacitor is obtained.

7. The method for preparing an ultra-thin BME ceramic capacitor prepared by step-by-step doping according to claim 3, characterized in that: In step six, the green body is degreased at 270-350° C. in a nitrogen atmosphere for 6-30 hours.

Images