CN108878148B - Multilayer ceramic capacitor and preparation method thereof - Google Patents
Multilayer ceramic capacitor and preparation method thereof Download PDFInfo
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- CN108878148B CN108878148B CN201810544643.0A CN201810544643A CN108878148B CN 108878148 B CN108878148 B CN 108878148B CN 201810544643 A CN201810544643 A CN 201810544643A CN 108878148 B CN108878148 B CN 108878148B
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Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/30—Stacked capacitors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/005—Electrodes
- H01G4/012—Form of non-self-supporting electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/018—Dielectrics
- H01G4/06—Solid dielectrics
- H01G4/08—Inorganic dielectrics
- H01G4/12—Ceramic dielectrics
- H01G4/1209—Ceramic dielectrics characterised by the ceramic dielectric material
- H01G4/1236—Ceramic dielectrics characterised by the ceramic dielectric material based on zirconium oxides or zirconates
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G4/00—Fixed capacitors; Processes of their manufacture
- H01G4/002—Details
- H01G4/228—Terminals
- H01G4/232—Terminals electrically connecting two or more layers of a stacked or rolled capacitor
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Ceramic Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
- Ceramic Capacitors (AREA)
Abstract
The invention discloses a preparation method of a multilayer ceramic capacitor, which comprises the steps of mixing a sintering block and a laminated body together, placing the mixture on a burning bearing plate, sintering the laminated body, and volatilizing combustion-supporting components in the sintering block to form local atmosphere with higher volatilization concentration around the laminated body, so that excessive volatilization of the combustion-supporting components in the laminated body can be prevented, and a ceramic body obtained after sintering is uniform, compact and good in consistency; the laminated body on the setter plate is surrounded by the sintering blocks in a clinging manner, so that the laminated body is within the influence range of local atmosphere formed by the sintering blocks regardless of the loading density of the laminated body, and the operation of placing the laminated body on the setter plate is convenient; each surface of the sintered block is provided with an inward concave area, so that when the sintered block and the laminated body are mixed together, the sintered block and the laminated body are difficult to form large-area contact, and a sintered ceramic body is difficult to adhere to the sintered block; the adhesive can be removed completely from the laminated body.
Description
Technical Field
The invention relates to a capacitor and a preparation method thereof, in particular to a multilayer ceramic capacitor and a preparation method thereof.
Background
The ceramic material is sintered at low temperature to be co-sintered with the copper inner electrode, so that the ceramic material generally contains a large amount of sintering-aid components so as to be sintered and compact at a temperature lower than the melting point of copper. Since the sintering aid component is likely to volatilize during high-temperature sintering, the ceramic chips mounted on the same setter plate are likely to have a problem of deteriorated uniformity. Specifically, when the ceramic chips loaded on the same burning board are sintered at high temperature, the ceramic chips with higher density are loaded, and because the concentration of the volatilization atmosphere of the sintering components is higher, the volatilization can be hindered, so that more sintering components are remained in the ceramic chips to form a liquid phase to promote the densification process of the ceramic chips, and the sintered ceramic chips are uniform and dense; and the ceramic chip with lower loading density has serious volatilization loss of the sintering-aid components because the concentration of the volatilization atmosphere of the sintering-aid components is lower, and the ceramic chip is difficult to sinter and compact. The above-mentioned phenomenon of deteriorated uniformity is manifested as partial ceramic chips or local color inconsistency of the ceramic chips, loose ceramic bodies, and low strength, and is particularly remarkable in the ceramic chips loaded at the outermost periphery.
As a countermeasure to the problem of the uniformity of sintering, there is known a powder burying sintering method in the art, for example, sintering a ceramic capacitor with powder containing a sintering aid component to improve the sintering atmosphere, but since the powder to be buried is in a relatively loose packed state and a sufficient local atmosphere is not provided, the problem cannot be solved.
CN201510347332.1 discloses a method for manufacturing a multilayer ceramic capacitor, in which a stacked body made of the same ceramic material and a green compact are placed on a setter plate together, and the green compact is sintered around the periphery of the stacked body, the green compact is subjected to a pressing step, so that the density is high, which can provide sufficient local atmosphere and ensure that the stacked body at the periphery obtains good sintering consistency, but for the stacked body at the middle position of the setter plate, when the loading density is low, the problem of sintering consistency still exists. On the other hand, since the ceramic material contains a large amount of the sintering aid, when the flat-surfaced laminate and the flat-surfaced green compact are brought into contact with each other, they tend to adhere to each other.
CN201510347334.0 discloses a method for manufacturing a multilayer ceramic capacitor, which comprises placing a laminate on a second substrate laminated and made of the same ceramic material, and then placing the second substrate on which the laminate is placed on a setter plate to sinter the laminate, so that the sintering uniformity can be solved regardless of the loading density of the laminate at each position on the setter plate. However, since the ceramic material contains a large amount of sintering components, there is a problem that the ceramic body and the second substrate are likely to adhere to each other after sintering.
CN201510347333.6 discloses a method for manufacturing a multilayer ceramic capacitor, which can also solve the problem of sintering consistency, and a separation film is disposed between the laminate and the first substrate, so that the two will not adhere after sintering. However, since the third substrate having a large volume is subjected to the binder removal, there is a problem that the binder contained in the stacked body is not completely removed, and the density and uniformity of the sintered ceramic body are reduced.
Disclosure of Invention
Accordingly, the present invention is directed to a method for manufacturing a multilayer ceramic capacitor that overcomes the above-mentioned disadvantages of the prior art.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a method for manufacturing a multilayer ceramic capacitor, comprising the steps of:
(1) uniformly mixing the first ceramic powder doped with the sintering aid, the adhesive and the organic solvent to obtain first ceramic slurry, and preparing a first ceramic membrane by taking the first ceramic slurry as a raw material;
(2) printing the first metal slurry on the first ceramic membrane to form an inner electrode pattern, and drying to obtain the first ceramic membrane printed with the inner electrode pattern;
(3) laminating the first ceramic films printed with the inner electrode patterns to obtain a first laminating unit, and then respectively laminating the first ceramic films obtained in the step (1) on two opposite side surfaces of the first laminating unit to obtain a first substrate;
(4) pressing the first substrate and then cutting to obtain a laminated body;
(5) uniformly mixing the second ceramic powder doped with the sintering aid, the adhesive and the organic solvent to obtain second ceramic slurry, and preparing a second ceramic membrane by taking the second ceramic slurry as a raw material;
(6) laminating a plurality of first ceramic films obtained in the step (1) to obtain a second laminating unit, and respectively laminating a plurality of second ceramic films obtained in the step (5) on two opposite side surfaces of the second laminating unit to obtain a second substrate;
or
Laminating a plurality of second ceramic films obtained in the step (5) to obtain a second laminating unit, respectively laminating a plurality of first ceramic films obtained in the step (1) on two opposite side surfaces of the second laminating unit to obtain a third laminating unit, and respectively laminating a plurality of second ceramic films obtained in the step (5) on two opposite side surfaces of the third laminating unit to obtain a second substrate;
(7) pressing the second substrate and then cutting to obtain a green block with a concave area;
(8) placing the green compact blocks on a burning bearing plate, and performing adhesive removal and sintering on the green compact blocks to obtain sintered blocks;
(9) mixing the laminated body and the sintered block, placing the laminated body and the sintered block on a burning bearing plate, and performing adhesive removal and sintering on the laminated body to obtain a ceramic body; and attaching two external electrodes to two end faces of the chamfered ceramic body to obtain the multilayer ceramic capacitor.
Preferably, in the step (1), in the first ceramic slurry, the mass ratio of the first ceramic powder doped with the sintering aid, the binder, and the organic solvent is: first ceramic powder doped with sintering aid: adhesive: organic solvent 10: (3-5): (6-9).
More preferably, the first ceramic powder is calcium zirconate or strontium zirconate; the sintering aid is SiO2Or Bi2O3(ii) a The adhesive is polyvinyl butyral; the organic solvent is a mixed solvent of toluene and ethanol, and the mass ratio of the toluene to the ethanol is (1-1.5): 1.
preferably, the first ceramic powder doped with the sintering aid, the binder and the organic solvent are uniformly mixed by a ball milling method, and the ball milling time is 10-16 h.
More preferably, in the first ceramic powder doped with the sintering aid, the mass percentage content of the sintering aid is 4% to 15%.
Preferably, the first ceramic slurry further comprises a modification additive, the modification additive is at least one of an oxide of calcium, an oxide of titanium and an oxide of manganese, and the mass ratio of the first ceramic powder doped with the sintering aid to the modification additive is as follows: first ceramic powder doped with sintering aid: modified additives (96-97): (3-4).
In the step (3) of the present invention, the first ceramic films on which the internal electrode patterns are printed are laminated in a predetermined number to obtain the first lamination unit. And then respectively laminating a first ceramic film on two opposite side surfaces of the first laminating unit to form two protective layers respectively covering the two opposite side surfaces of the first laminating unit, and forming a structure in which the protective layer, the first laminating unit and the protective layer are sequentially laminated to obtain the first substrate.
In general, the first lamination unit may be obtained by laminating 1 to 40 first ceramic films on which the internal electrode patterns are printed. The two protective layers respectively covering the two opposite side surfaces of the laminating unit can be obtained by laminating 1-20 first ceramic films.
In the step (4), the first substrate is fixed and pressed by an isostatic pressing method, so that the film layers in the first substrate are tightly bonded; the first substrate is then cut into a plurality of rectangular parallelepiped stacks by cutting the first substrate into long and short pieces with a predetermined size.
Preferably, in the step (6), the slurry is printed on the first ceramic film obtained in the step (1) to form an additional layer, and the first ceramic film printed with the additional layer is obtained after drying; the slurry is one of ceramic slurry, glass slurry, resin slurry and metal slurry;
then laminating a plurality of first ceramic films printed with additional layers to obtain a second laminating unit, and respectively laminating a plurality of second ceramic films obtained in the step (5) on two opposite side surfaces of the second laminating unit to obtain a second substrate;
or
And (3) laminating a plurality of second ceramic films obtained in the step (5) to obtain a second laminating unit, laminating a plurality of first ceramic films printed with additional layers on two opposite side surfaces of the second laminating unit respectively to obtain a third laminating unit, and laminating a plurality of second ceramic films obtained in the step (5) on two opposite side surfaces of the third laminating unit respectively to obtain a second substrate.
More preferably, the thickness of the additional layer is 2-5 μm. If the additional layer is too thick, an excessively high step is formed, and when a plurality of first ceramic films printed with the additional layer are stacked, sliding displacement is likely to occur, and the additional layers cannot be aligned in the stacking direction; too thin an additional layer requires too many first ceramic films to be stacked in order to provide a sufficient difference in thickness between the area of the second substrate having the additional layer and the area without the additional layer.
Preferably, the pattern of the additional layer is a plurality of rectangles or a plurality of diamonds. The edges of the patterns are straight, so that the patterns are simple and convenient to manufacture and print. The elongated rectangle is more convenient to manufacture and print, and the scattered diamonds have smaller printing area, so that the paste can be saved.
Because the second substrate is internally provided with a plurality of additional layers which are stacked in an aligned mode, the thickness difference exists between the area with the additional layers and the area without the additional layers in the second substrate, so that the plastic sheets are covered on two sides of the second substrate and then the second substrate is pressed, and two opposite surfaces of the second substrate after pressing, which are perpendicular to the pressing direction, can be formed into surfaces with a plurality of concave areas.
Preferably, the mass percentage content of the sintering aid in the second ceramic powder is less than that of the sintering aid in the first ceramic powder;
or the mass percentage of the binder in the second ceramic slurry is less than that of the binder in the first ceramic slurry.
The green compact shrinks during sintering, and because the mass percentage of the sintering aid contained in the first ceramic film forming the first lamination part is greater than the mass percentage of the sintering aid contained in the second ceramic film forming the second lamination part, or because the mass percentage of the binder in the first ceramic slurry for forming the first lamination part is greater than the mass percentage of the binder in the second ceramic slurry for forming the second ceramic film, the shrinkage rate of the first lamination part is greater than that of the second lamination part, and as a result, four originally flat surfaces of the green compact parallel to the lamination direction of the additional layer respectively form inward recessed areas.
Preferably, in the step (8), the sintered compact includes a first sintered portion and a second sintered portion; the first sintering part is formed by a first laminating part through adhesive discharge and sintering, and the first laminating part is formed by laminating a plurality of first ceramic membranes printed with additional layers; the second sintering part is formed by a second laminated part through adhesive removal and sintering, and the second laminated part is formed by laminating a plurality of second ceramic membranes; the second laminated portion is laminated on opposite side surfaces of the first laminated portion.
More preferably, the thickness of the first sintered part is less than the length of the shortest edge of the laminated body, and the thickness of the second sintered part is less than 0.1 mm.
This makes it easier to prevent the sintered cake from making a large area contact with the stacked body. By controlling the number of the laminated first ceramic membrane and the second ceramic membrane, the process parameters such as the pressure used for laminating the second substrate and the cutting step distance for cutting the second substrate, the edge size of the sintered block and the thicknesses of the first sintered part and the second sintered part can be conveniently controlled.
Preferably, the method further comprises the step of thoroughly mixing the laminate with corn starch prior to placing the laminate on the setter plate. This makes it possible to adhere corn starch to the surface of the laminate, and the corn starch serves as a barrier and helps prevent the ceramic bodies from sticking to each other after sintering and to the sintered cake.
In the operation of removing the adhesion and sintering the green compact, the specific process of removing the adhesion is as follows: heating the green block to 260-450 ℃ in the air atmosphere, and keeping the temperature for 2-4 hours to remove the adhesive; or heating the green compact to 400-600 ℃ in a protective gas atmosphere and preserving the temperature for 3-6 hours to remove the adhesive.
The protective gas atmosphere may be a nitrogen atmosphere, an argon atmosphere, or a helium atmosphere.
In the operation of removing adhesion and sintering the green compact, the sintering process is as follows: and heating the green compact blocks subjected to binder removal to 980-1050 ℃ in a reducing gas atmosphere, preserving heat for 1.5-3 h, sintering, and obtaining sintered blocks after sintering.
The reducing gas atmosphere can be a mixed gas atmosphere of nitrogen and hydrogen, wherein the volume ratio of the hydrogen to the nitrogen is (0.1-3): 100.
preferably, in the step (1), the thickness of the first ceramic film is 5-40 μm; in the step (5), the thickness of the second ceramic film is 10-40 μm.
The thickness of the first ceramic film is set to this range, so that a capacitor can be produced with a large range of electrostatic capacity and a small volume of the sintered compact. The thickness range of the second ceramic film makes it easier to prepare the second ceramic film and improves the efficiency of laminating the second ceramic film.
Preferably, each of the six faces of the sintered cake has two inwardly recessed regions.
Preferably, when a plurality of first ceramic films on which the additional layers are printed are stacked, the additional layers at corresponding positions on each first ceramic film are aligned one by one in the stacking direction. This makes it possible to form a thickness difference at a given position.
Preferably, in the step (9), the stacked body and the sintered block are mixedly placed on the setter plate so that the sintered block completely surrounds the outermost stacked body.
During sintering, the sintering aid components in the sintered blocks volatilize, so that local atmosphere with higher volatilization concentration is formed around the laminated body, excessive volatilization of the sintering aid components in the laminated body can be prevented, and the sintered ceramic body is uniform, compact and good in consistency. The sintered compacts are arranged to completely surround the outermost stacks and substantially fill the interstices between the stacks, and it is further preferred that the sintered compacts completely cover all of the stacks, so as to ensure that all of the stacks are within the influence of the local atmosphere provided by the sintered compacts during sintering.
Meanwhile, the invention also provides a multilayer ceramic capacitor prepared by the preparation method.
Compared with the prior art, the invention has the beneficial effects that:
in the preparation process of the multilayer ceramic capacitor, the sintering blocks and the laminated body are mixed together and placed on the sintering bearing plate, then the laminated body is sintered, and the sintering-aid components in the sintering blocks volatilize to form local atmosphere with higher volatilization concentration around the laminated body, so that the excessive volatilization of the sintering-aid components in the laminated body can be prevented, and the sintered ceramic body is uniform, compact and good in consistency;
the preparation of the sintering block is carried out through the step of pressing, so that the density is higher, and enough local atmosphere can be provided for the laminated body during sintering;
the laminated body on the setter plate is surrounded by the sintering blocks in a clinging manner, so that the laminated body is within the influence range of local atmosphere formed by the sintering blocks regardless of the loading density of the laminated body, and the operation of placing the laminated body on the setter plate is convenient;
each surface of the sintered block is provided with an inward concave area, so that when the sintered block and the laminated body are mixed together, the sintered block and the laminated body are difficult to form large-area contact, and a sintered ceramic body is difficult to adhere to the sintered block;
the adhesive can be completely removed from the laminated body, and the density and the dielectric property of the ceramic body are better.
Drawings
FIG. 1 is a flow chart of a method for manufacturing a multilayer ceramic capacitor according to the present invention;
FIG. 2 is a schematic view of the pattern of the additional layer of the present invention as a plurality of rectangles;
FIG. 3 is a schematic view of an additional layer according to the present invention patterned with a plurality of diamonds;
fig. 4 is a side view of a second substrate obtained after stacking a first ceramic film and a second ceramic film;
FIG. 5 is a schematic view illustrating pressing a second substrate;
FIG. 6 is a side view of the second substrate after bonding;
FIG. 7 is a schematic view illustrating the second substrate after being bonded;
FIG. 8 is a schematic view illustrating the second substrate after being bonded;
fig. 9 is a side view of a green block in the first embodiment;
FIG. 10 is a side view of a sintered compact in the first embodiment;
FIG. 11 is a top view of the stack being placed on a setter plate as the stack is sintered;
FIG. 12 is a top view of the laminate, sintered cake, and setter plates as the laminate is sintered;
FIG. 13 is a side view of a green block of the third embodiment;
FIG. 14 is a side view of a sintered compact of the third embodiment;
FIG. 15 is a side view of a fourth embodiment in which a second substrate is pressed;
FIG. 16 is a graph showing DC breakdown voltages of the multilayer ceramic capacitors of examples 1 to 5 and comparative examples 1 to 4;
wherein 22, an additional layer; 201. a first lamination portion; 202. a second laminated part; 203. a first sintering section; 204. a second sintering section; 10. a laminate; 20. sintering blocks; 30. a setter plate; 4. a plastic sheet; 5. a template having a plurality of grooves.
Detailed Description
To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to the accompanying drawings and specific embodiments.
First embodiment
An embodiment of the multilayer ceramic capacitor of the present invention, with reference to fig. 1, is prepared by the following method:
step 1: the first ceramic powder doped with the sintering aid, the adhesive and the organic solvent are uniformly mixed to obtain first ceramic slurry, and then the first ceramic slurry is used as a raw material to prepare the first ceramic membrane.
In this embodiment, the operation of uniformly mixing the first ceramic powder doped with the sintering aid, the binder, and the organic solvent is as follows: the first ceramic powder doped with the sintering aid, the adhesive and the organic solvent are uniformly mixed by a ball milling method, and the ball milling time can be 10-16 h.
In the first ceramic slurry, the mass ratio of the first ceramic powder doped with the sintering aid, the binder and the organic solvent is 10: (3-5): (6-9).
In the present embodiment, the mass percentage of the sintering aid in the first ceramic powder doped with the sintering aid is 4% to 15%. The ceramic powder has calcium zirconate or strontium zirconate as main component and SiO as sintering assistant2Or Bi2O3The adhesive is polyvinyl butyral, and the organic solvent is prepared from (1-1.5) by mass: 1 of a mixed solvent of toluene and ethanol.
In a preferred embodiment, the first ceramic slurry further comprises a modifying additive. The modified additive can be an oxide of calcium, an oxide of titanium or an oxide of manganese, and the mass ratio of the first ceramic powder doped with the sintering aid to the modified additive is (96-97): (3-4).
In the operation of preparing the first ceramic film by using the first ceramic slurry as a raw material, the first ceramic film may be formed from the first ceramic slurry by a tape casting method, and the thickness of the obtained first ceramic film may be 5 μm to 40 μm.
Step 2: and printing the first metal slurry on the first ceramic film to form an inner electrode pattern, and drying to obtain the first ceramic film printed with the inner electrode pattern.
In the operation of printing the first metal paste on the first ceramic film to form the internal electrode pattern, the metal in the metal paste may be copper, and the printing selects a screen printing process.
And step 3: and laminating the first ceramic films printed with the inner electrode patterns to obtain a first laminating unit, and then respectively laminating first ceramic films on two opposite side surfaces of the first laminating unit to obtain a first substrate.
And laminating the first ceramic films printed with the inner electrode patterns according to a preset number to obtain a first lamination unit. And then respectively laminating a first ceramic film on two opposite side surfaces of the first laminating unit to form two protective layers respectively covering the two opposite side surfaces of the first laminating unit, and forming a structure in which the protective layer, the first laminating unit and the protective layer are sequentially laminated to obtain the first substrate.
In general, the first lamination unit may be obtained by laminating 1 to 40 first ceramic films on which the internal electrode patterns are printed. The two protective layers respectively covering the two opposite side surfaces of the laminating unit can be obtained by laminating 1-20 first ceramic films.
And 4, step 4: and pressing the first substrate and then cutting to obtain the laminated body.
The step 4 may specifically be: fixing the first substrate by isostatic pressing to tightly bond the film layers in the first substrate; the first substrate is then cut into a plurality of rectangular parallelepiped stacks by cutting the first substrate into long and short pieces with a predetermined size.
And 5: and uniformly mixing the second ceramic powder doped with the sintering aid, the adhesive and the organic solvent to obtain second ceramic slurry, and then preparing the second ceramic membrane by taking the second ceramic slurry as a raw material.
The operation of uniformly mixing the second ceramic powder doped with the sintering aid, the binder, and the organic solvent is preferably the same as in step 1.
And in the second ceramic powder doped with the sintering aid, the mass percentage of the sintering aid is less than that of the sintering aid in the first ceramic powder.
In the second ceramic slurry, the other components and the mixture ratio of the components are preferably the same as those of the first ceramic slurry except that the second ceramic powder is different from the first ceramic powder in the first ceramic slurry.
The operation of preparing the second ceramic film using the second ceramic slurry as a raw material is preferably the same as in step 1.
The thickness of the second ceramic film obtained may be 10 to 40 μm. The mass percentage of the sintering aid in the second ceramic film is less than that of the sintering aid in the first ceramic film.
Step 6: and printing the second metal slurry on the first ceramic film to form an additional layer, and drying to obtain the first ceramic film printed with the additional layer.
In the operation of printing the second metal paste on the first ceramic film to form the additional layer, the metal in the second metal paste may be nickel, copper, nickel-copper alloy, silver-palladium alloy, etc., preferably nickel, and the printing selects the screen printing process. The pattern of the additional layer 22 is shown in fig. 2 as a plurality of rectangles. The thickness of the additional layer may be between 2 microns and 5 microns.
In other embodiments, the pattern of the additional layer may be a plurality of diamonds as shown in FIG. 3.
In other embodiments, ceramic paste, glass paste, resin paste, or the like may be used instead of the second metal paste.
And 7: the second substrate is obtained by laminating a plurality of first ceramic films on which the additional layers are printed, to obtain a second lamination unit, and then laminating a plurality of second ceramic films on both side surfaces of the second lamination unit, which face each other.
When a plurality of first ceramic films on which additional layers are printed are laminated, the additional layers at corresponding positions on each first ceramic film are aligned one by one in the laminating direction, and the second substrate obtained after lamination is as shown in fig. 4.
In general, the second lamination unit may be obtained by laminating 16 to 40 first ceramic films on which additional layers are printed. The number of the second ceramic films laminated on the two opposite side surfaces of the second lamination unit may be 2 to 16.
And 8: and pressing the second substrate and then cutting to obtain a green block.
The step 8 may specifically be: as shown in fig. 5, two plastic sheets 4 (for example, a silicone plate with plastic properties) are respectively covered on two sides of the second substrate, and then the second substrate covered with plastic sheets on two sides is pressed together by isostatic pressing method, so that the film layers in the second substrate are tightly bonded; and then, cutting the second substrate in a longitudinal and transverse mode according to a preset size to obtain a plurality of green blocks.
The second substrate after bonding is shown in fig. 6. Since the second substrate has a plurality of additional layers stacked in alignment, in the second substrate, there is a difference in thickness between the region having the additional layers and the region having no additional layers, so that the plastic sheet is covered on both sides of the second substrate and then the second substrate is bonded, and two surfaces of the bonded second substrate, which are opposite to each other in a direction perpendicular to the bonding direction, can be formed as surfaces having a plurality of recessed regions.
The second substrate is cut as shown in fig. 7 and 8, with the additional layers also being cut across. The green block obtained by cutting the second substrate is, as shown in fig. 9, substantially rectangular and has two mutually opposed faces having an inwardly recessed region and the remaining four faces being flat faces. The green block comprises one first laminate 201 and two second laminates 202. The first laminate is formed by laminating a plurality of first ceramic films on which the additional layers 22 are printed. Two second laminated portions are laminated on opposite side surfaces of the first laminated portion, respectively, and are formed by laminating a plurality of second ceramic films.
And step 9: and placing the green compact blocks on a burning bearing plate, and then performing adhesive removal and sintering on the green compact blocks to obtain sintered blocks.
The green briquettes are placed on a setter plate, preferably without overlap, to prevent sheet sticking between the briquettes.
In the operation of removing the adhesion and sintering the green compact, the specific process of removing the adhesion is as follows: heating the green block to 260-450 ℃ in the air atmosphere, and keeping the temperature for 2-4 hours to remove the adhesive; or heating the green compact to 400-600 ℃ in a protective gas atmosphere and preserving the temperature for 3-6 hours to remove the adhesive.
The protective gas atmosphere may be a nitrogen atmosphere, an argon atmosphere, or a helium atmosphere.
In the operation of removing adhesion and sintering the green compact, the sintering process is as follows: and heating the green compact blocks subjected to binder removal to 980-1050 ℃ in a reducing gas atmosphere, preserving heat for 1.5-3 h, sintering, and obtaining sintered blocks after sintering.
The reducing gas atmosphere can be a mixed gas atmosphere of nitrogen and hydrogen, wherein the volume ratio of the hydrogen to the nitrogen is (0.1-3): 100.
the green compact shrinks during sintering, and since the mass percentage of the sintering aid contained in the first ceramic film constituting the first lamination portion is greater than the mass percentage of the sintering aid contained in the second ceramic film constituting the second lamination portion, the shrinkage rate of the first lamination portion is greater than the shrinkage rate of the second lamination portion, and as a result, four originally flat surfaces of the green compact parallel to the lamination direction of the additional layers form inwardly recessed regions, respectively. The sintered cake obtained by sintering is a substantially rectangular body and has regions depressed inward on six faces, as shown in FIG. 10. The sintered compact includes a first sintered portion 203 formed by row bonding and sintering of the first stacked portion and a second sintered portion 204 formed by row bonding and sintering of the second stacked portion. The thickness of the first sintered part is T, preferably T is less than the length of the shortest edge of the laminate. The thickness of the second sintered portion is preferably less than 0.1mm, and the volume of the sintered compact can be reduced and the contact area of the sintered compact and the stacked body can be reduced. The agglomerates are preferably cubes. By controlling the number of the laminated first ceramic membrane and the second ceramic membrane, the process parameters such as the pressure used for laminating the second substrate and the cutting step distance for cutting the second substrate, the edge size of the sintered block and the thicknesses of the first sintered part and the second sintered part can be conveniently controlled.
Step 10: and placing the laminated body on a setter plate, placing the sintered block on the setter plate and mixing the sintered block and the laminated body together, and then performing arrangement adhesion and sintering on the laminated body to obtain the ceramic body.
As shown in fig. 11, the stacked body 10 is placed on the setter 30, preferably without overlapping, to prevent sticking between the sintered ceramic bodies. The agglomerates 20 may then be uniformly sprinkled onto a setter plate using a screen to mix the agglomerates with the stack, as shown in fig. 12. And then the laminated body is subjected to adhesive removal and sintering to obtain the ceramic body. During sintering, the sintering aid components in the sintered blocks volatilize, so that local atmosphere with higher volatilization concentration is formed around the laminated body, excessive volatilization of the sintering aid components in the laminated body can be prevented, and the sintered ceramic body is uniform, compact and good in consistency. Preferably, the agglomerates completely surround the outermost stacks and the agglomerates substantially fill the interstices between the stacks, and further preferably, the agglomerates completely cover all of the stacks, thus ensuring that all of the stacks are within the influence of the local atmosphere provided by the agglomerates during sintering.
When the sinter cake is cube, the sinter cake can easily pass through the sieve holes when being screened by the sieve, and the operation is convenient.
In the operation of removing the adhesion and sintering the laminated body, the specific process of removing the adhesion is as follows: and heating the laminated body to 400-600 ℃ in a protective gas atmosphere, and keeping the temperature for 3-6 h to remove the adhesive.
The protective gas atmosphere may be a nitrogen atmosphere, an argon atmosphere, or a helium atmosphere.
In the operation of removing adhesion and sintering the laminated body, the sintering process comprises the following specific steps: and heating the laminated body after the viscosity removal to 980-1050 ℃ in a reducing gas atmosphere, preserving the heat for 1.5-3 h, sintering, and obtaining the ceramic body after sintering.
The reducing gas atmosphere can be a mixed gas atmosphere of nitrogen and hydrogen, wherein the volume ratio of the hydrogen to the nitrogen is (0.1-3): 100.
because each surface of the sintered block is provided with the inwards concave area, when the sintered block and the laminated body are mixed together, the sintered block and the laminated body are difficult to form large-area contact, and therefore, the sintered ceramic body is difficult to adhere to the sintered block. When the thickness of the first sintered part is less than the length of the shortest edge of the stack, it is easier to prevent the sintered cake from making a larger area of contact with the stack.
If necessary, before the laminated body is placed on the setter plate, a step of fully mixing the laminated body with corn starch can be added, so that the corn starch is adhered to the surface of the laminated body, and the corn starch plays a role in blocking adhesion and helps to prevent adhesion between the sintered ceramic bodies and between the ceramic bodies and the sintered blocks.
After sintering, the ceramic body and the sintered block can be screened by using the size difference. In particular, when the material of the additional layer in the sintered cake is nickel, the ceramic body can be separated from the sintered cake more conveniently by magnetic separation, and then the green cake is subjected to de-sticking in step 9, preferably in a protective gas atmosphere, to prevent nickel from being oxidized and making magnetic separation difficult.
Step 11: and after chamfering the ceramic body, attaching two external electrodes to two end faces of the chamfered ceramic body respectively to obtain the multilayer ceramic capacitor.
The chamfering operation of the ceramic body may be: the ceramic body is chamfered by a planetary grinding or barreling method to make the corners smooth.
The operation of attaching two external electrodes to the two end faces of the chamfered ceramic body is specifically as follows: respectively coating copper metal slurry on two end faces of the chamfered ceramic body, heating the ceramic body coated with the copper metal slurry to 750-850 ℃ in a protective gas atmosphere, preserving the heat for 10-12 min to sinter the copper metal slurry, and forming two external electrodes which are respectively and tightly attached to the two end faces of the ceramic body after sintering.
The protective gas atmosphere may be a nitrogen atmosphere, an argon atmosphere, or a helium atmosphere.
It is understood that in the above method for manufacturing a multilayer ceramic capacitor, the manufacturing of the ceramic body and the manufacturing of the sintered compact may be performed simultaneously, and the debinding of the stacked body and the debinding of the green compact may be performed using the same temperature profile and atmosphere system, the sintering of the stacked body and the sintering of the green compact may be performed using the same temperature profile and atmosphere system, and thus the manufacturing may be facilitated.
Second embodiment
In an embodiment of the multilayer ceramic capacitor according to the present invention, the multilayer ceramic capacitor according to the present embodiment is prepared by the following method:
the difference from the first embodiment is substantially the same as that of the first embodiment:
and 5: and uniformly mixing the first ceramic powder doped with the sintering aid, the adhesive and the organic solvent to obtain second ceramic slurry, and then preparing the second ceramic membrane by taking the second ceramic slurry as a raw material.
The operation of uniformly mixing the first ceramic powder doped with the sintering aid, the binder, and the organic solvent is preferably the same as in step 1.
In the second ceramic slurry, the mass percentage of the binder is smaller than that in the first ceramic slurry.
The operation of preparing the second ceramic film using the second ceramic slurry as a raw material is preferably the same as in step 1.
The thickness of the second ceramic film obtained may be 10 to 40 μm.
Third embodiment
In an embodiment of the multilayer ceramic capacitor according to the present invention, the multilayer ceramic capacitor according to the present embodiment is prepared by the following method:
And 7: and laminating a plurality of second ceramic films to obtain a second laminating unit, then laminating a plurality of first ceramic films printed with additional layers on two opposite side surfaces of the second laminating unit to obtain a third laminating unit, and then laminating a plurality of second ceramic films on two opposite side surfaces of the third laminating unit to obtain a second substrate.
When a plurality of first ceramic films printed with additional layers are laminated, the additional layers at corresponding positions on each first ceramic film are respectively aligned in the laminating direction.
And 8: and pressing the second substrate and then cutting to obtain a green block.
The step 8 may specifically be: covering a plastic sheet (such as a silica gel plate with plasticity) on each of two sides of the second substrate, and pressing the second substrate covered with the plastic sheets on the two sides by an isostatic pressing method to tightly bond the film layers in the second substrate; and then, cutting the second substrate in a longitudinal and transverse mode according to a preset size to obtain a plurality of green blocks.
Since the second substrate has a plurality of additional layers stacked in alignment, in the second substrate, there is a difference in thickness between the region having the additional layers and the region having no additional layers, so that the plastic sheet is covered on both sides of the second substrate and then the second substrate is bonded, and two surfaces of the bonded second substrate, which are opposite to each other in a direction perpendicular to the bonding direction, can be formed as surfaces having a plurality of recessed regions.
The second substrate is diced so that the additional layers are also diced vertically and horizontally. As shown in fig. 13, the green block obtained by cutting the second substrate is substantially rectangular and has two surfaces facing each other and each having two inwardly recessed regions, and the remaining four surfaces are flat surfaces. The green block includes two first stacked portions and three second stacked portions which are alternately stacked. The first laminated portion is formed by laminating a plurality of first ceramic films on which additional layers are printed. The second laminated portion is formed by laminating a plurality of second ceramic films. Two first laminated parts are respectively laminated on two opposite sides of one second laminated part, and the other two second laminated parts are respectively laminated on the other sides of the two first laminated parts.
And step 9: and placing the green compact blocks on a burning bearing plate, and then performing adhesive removal and sintering on the green compact blocks to obtain sintered blocks.
In the operation of removing the adhesion and sintering the green compact, the specific process of removing the adhesion is as follows: heating the green block to 260-450 ℃ in the air atmosphere, and keeping the temperature for 2-4 hours to remove the adhesive; or heating the green compact to 400-600 ℃ in a protective gas atmosphere and preserving the temperature for 3-6 hours to remove the adhesive.
The protective gas atmosphere may be a nitrogen atmosphere, an argon atmosphere, or a helium atmosphere.
In the operation of removing adhesion and sintering the green compact, the sintering process is as follows: and heating the green compact blocks subjected to binder removal to 980-1050 ℃ in a reducing gas atmosphere, preserving heat for 1.5-3 h, sintering, and obtaining sintered blocks after sintering.
The reducing gas atmosphere can be a mixed gas atmosphere of nitrogen and hydrogen, wherein the volume ratio of the hydrogen to the nitrogen is (0.1-3): 100.
the green compact shrinks during sintering, and since the mass percentage of the sintering aid contained in the first ceramic film constituting the first lamination portion is greater than the mass percentage of the sintering aid contained in the second ceramic film constituting the second lamination portion, the shrinkage rate of the first lamination portion is greater than the shrinkage rate of the second lamination portion, and as a result, two regions are formed in the green compact parallel to the originally flat four surfaces of the lamination direction of the additional layer. The sintered compact obtained by sintering is a substantially rectangular body and has two inwardly depressed regions on each of its six faces, as shown in fig. 14. The sintered block includes a first sintered portion formed by the first stacked portion through row bonding and sintering, and a second sintered portion formed by the second stacked portion through row bonding and sintering. The thickness of the first sintered part is T, preferably T is less than the length of the shortest edge of the laminate. The thickness of the second sintered portion is preferably less than 0.1mm, and the volume of the sintered compact can be reduced and the contact area of the sintered compact and the stacked body can be reduced. The agglomerates are preferably cubes. By controlling the number of the laminated ceramic films, the technological parameters such as pressure for pressing the second substrate and the cutting step distance for cutting the second substrate, the edge size of the sintered block and the thicknesses of the first sintered part and the second sintered part can be conveniently controlled.
Steps 10 to 11 are the same as those in the first embodiment. However, in the present embodiment, since the six faces of the sintered compact each have two inwardly recessed regions, and the thickness of the recessed regions (i.e., the thickness of the first sintered part and the second sintered part) is smaller than that of the first embodiment in which only one of the six faces is recessed, when the sintered compact and the laminate are mixed, it is easier to prevent the sintered compact from coming into contact with the laminate over a larger area, and the sintered ceramic body is less likely to adhere to the sintered compact. It will be appreciated that the size of the agglomerates of this embodiment may be selected from a wider range than in the first embodiment, and in particular when making small size ceramic bodies, still allows the size of the agglomerates to be larger, thereby facilitating the preparation of the agglomerates.
Fourth embodiment
In an embodiment of the multilayer ceramic capacitor according to the present invention, the multilayer ceramic capacitor according to the present embodiment is prepared by the following method:
the difference from the first embodiment is substantially the same as that of the first embodiment: there is no additional layer in the sintered cake, i.e. the operation of step 6 is dispensed with.
Step 6: the plurality of first ceramic films are laminated to obtain a second lamination unit, and then the plurality of second ceramic films are laminated on two opposite side surfaces of the second lamination unit to obtain a second substrate.
Generally, the second lamination unit may be obtained by laminating 16 to 40 first ceramic films. The number of the second ceramic films laminated on the two opposite side surfaces of the second lamination unit may be 2 to 16.
And 7: and pressing the second substrate and then cutting to obtain a green block.
The step 7 may specifically be: as shown in fig. 15, two templates 5 having a plurality of grooves are used to clamp two sides of the second substrate, and the second substrate is pressed together by isostatic pressing to tightly bond the film layers in the second substrate; and then, cutting the second substrate in a longitudinal and transverse mode according to a preset size to obtain a plurality of green blocks.
Two surfaces of the second substrate which are opposite to each other and vertical to the pressing direction after the pressing are formed into a shape corresponding to the template, namely, a surface with a plurality of concave areas.
Step 8, step 9, and step 10 of the fourth embodiment correspond to step 9, step 10, and step 11 of the first embodiment, respectively.
Fifth embodiment
In an embodiment of the multilayer ceramic capacitor according to the present invention, the multilayer ceramic capacitor according to the present embodiment is prepared by the following method:
the difference from the first embodiment is substantially the same as that of the first embodiment: there is no additional layer in the sintered cake, i.e. the operation of step 6 is dispensed with.
Step 6: the plurality of first ceramic films are laminated to obtain a second lamination unit, and then the plurality of second ceramic films are laminated on two opposite side surfaces of the second lamination unit to obtain a second substrate.
Generally, the second lamination unit may be obtained by laminating 16 to 40 first ceramic films. The number of the second ceramic films laminated on the two opposite side surfaces of the second lamination unit may be 2 to 16.
And 7: and pressing the second substrate and then cutting.
The step 7 may specifically be: pressing the second substrate by an isostatic pressing method to tightly bond the film layers in the second substrate; and then respectively carrying out longitudinal, transverse or longitudinal and transverse bidirectional cutting on two opposite surfaces of the pressed second substrate, which are vertical to the pressing direction, so that the two cut surfaces of the second substrate are provided with a plurality of grooves.
And 8: and cutting the second substrate after cutting longitudinally and transversely to obtain a green block.
The resulting green block is generally rectangular and has two mutually opposed faces with inwardly recessed regions and the remaining four faces being flat faces.
Steps 9 to 11 are the same as those of the first embodiment.
Multilayer ceramic capacitors (0201 standard, nominal electrostatic capacity of 2.7pF, electrostatic capacity error class B) of examples 1 to 5 and comparative examples 1 to 4 were compared, wherein comparative example 1 was a laminate sintered by powder burying method, and comparative examples 2, 3 and 4 were laminates sintered by methods of CN201510347332.1, CN201510347334.0 and CN201510347333.6, respectively. The average density of 1 ten thousand ceramic bodies was measured by a drainage method, external electrodes were formed on the ceramic bodies, electrostatic capacity was measured at 25 ℃ using an HP4278A capacitance meter at a test frequency of 1MHz and a test frequency of 1.0Vrms, and DC breakdown voltage was measured using a withstand voltage tester. The measurement test results are shown in table 1 and fig. 16.
TABLE 1 measurement test results
As can be seen from table 1 and fig. 16, all the laminates in examples 1 to 5 were protected by the local atmosphere provided by the sintered cake, and the binder removal was also thorough, so the sintered ceramic body was acceptable in appearance, good in consistency, free from the phenomenon of sticking, high in density, good in dielectric properties, and high in concentration. The landfill powder of comparative example 1 failed to provide sufficient local atmosphere due to loose packing, resulting in a large proportion of ceramic body with abnormal appearance, decreased density, and severe dispersion of both electrostatic capacity and dc breakdown voltage. In comparative example 2, the individual stacked bodies having a small loading density at the central position of the setter were not protected by the local atmosphere provided by the green block, so that there were a certain proportion of ceramic bodies having inconsistent appearance, decreased density and dispersed dielectric properties, and there was a phenomenon in which the ceramic bodies and the sintered green blocks were stuck due to a large contact area between the stacked bodies and the green blocks. Comparative example 3 has no problem of uniformity in appearance and is excellent in dielectric properties, but since the ceramic body has a large contact area with the second substrate in this example, a large proportion of adhesive sheets are present and it is not suitable for mass production. The ceramic body of comparative example 4 was satisfactory in appearance and had no sticking piece, but the binder was not completely removed, which hindered the densification of the laminate during sintering, and the density was significantly reduced, and the electrostatic capacity and the dc breakdown voltage were significantly dispersed because the density and uniformity of the ceramic body were poor. In conclusion, the ceramic body prepared by the method is uniform and compact, good in consistency and excellent in dielectric property.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (8)
1. A method for manufacturing a multilayer ceramic capacitor, comprising the steps of:
(1) uniformly mixing the first ceramic powder doped with the sintering aid, the adhesive and the organic solvent to obtain first ceramic slurry, and preparing a first ceramic membrane by taking the first ceramic slurry as a raw material;
(2) printing the first metal slurry on the first ceramic membrane to form an inner electrode pattern, and drying to obtain the first ceramic membrane printed with the inner electrode pattern;
(3) laminating the first ceramic films printed with the inner electrode patterns to obtain a first laminating unit, and then respectively laminating the first ceramic films obtained in the step (1) on two opposite side surfaces of the first laminating unit to obtain a first substrate;
(4) pressing the first substrate and then cutting to obtain a laminated body;
(5) uniformly mixing the second ceramic powder doped with the sintering aid, the adhesive and the organic solvent to obtain second ceramic slurry, and preparing a second ceramic membrane by taking the second ceramic slurry as a raw material;
(6) laminating a plurality of first ceramic films obtained in the step (1) to obtain a second laminating unit, and respectively laminating a plurality of second ceramic films obtained in the step (5) on two opposite side surfaces of the second laminating unit to obtain a second substrate;
or
Laminating a plurality of second ceramic films obtained in the step (5) to obtain a second laminating unit, respectively laminating a plurality of first ceramic films obtained in the step (1) on two opposite side surfaces of the second laminating unit to obtain a third laminating unit, and respectively laminating a plurality of second ceramic films obtained in the step (5) on two opposite side surfaces of the third laminating unit to obtain a second substrate;
(7) pressing the second substrate and then cutting to obtain a green block with a concave area;
(8) placing the green compact blocks on a burning bearing plate, and performing adhesive removal and sintering on the green compact blocks to obtain sintered blocks;
(9) mixing the laminated body and the sintered block, placing the laminated body and the sintered block on a burning bearing plate, and performing adhesive removal and sintering on the laminated body to obtain a ceramic body; then attaching two external electrodes on two end faces of the chamfered ceramic body to obtain the multilayer ceramic capacitor;
in the step (6), the slurry is printed on the first ceramic film obtained in the step (1) to form an additional layer, and the first ceramic film printed with the additional layer is obtained after drying; the slurry is one of ceramic slurry, glass slurry, resin slurry and metal slurry;
then laminating a plurality of first ceramic films printed with additional layers to obtain a second laminating unit, and respectively laminating a plurality of second ceramic films obtained in the step (5) on two opposite side surfaces of the second laminating unit to obtain a second substrate;
or
Then, laminating a plurality of second ceramic films obtained in the step (5) to obtain a second laminating unit, laminating a plurality of first ceramic films printed with additional layers on two opposite side surfaces of the second laminating unit respectively to obtain a third laminating unit, and laminating a plurality of second ceramic films obtained in the step (5) on two opposite side surfaces of the third laminating unit respectively to obtain a second substrate;
the pattern of the additional layer is a plurality of rectangles or a plurality of diamonds.
2. The method of claim 1, wherein the additional layer has a thickness of 2 to 5 μm.
3. The method of producing a multilayer ceramic capacitor as claimed in claim 1, wherein the mass percentage content of the sintering aid in the second ceramic powder is smaller than the mass percentage content of the sintering aid in the first ceramic powder;
or the mass percentage of the binder in the second ceramic slurry is less than that of the binder in the first ceramic slurry.
4. The method of producing a multilayer ceramic capacitor as claimed in claim 1, wherein in the step (8), the sintered compact includes a first sintered portion and a second sintered portion; the first sintering part is formed by a first laminating part through adhesive discharge and sintering, and the first laminating part is formed by laminating a plurality of first ceramic membranes printed with additional layers; the second sintering portion is formed by a second laminating portion through debinding and sintering, and the second laminating portion is formed by laminating a plurality of second ceramic films.
5. The method of claim 4, wherein the first sintered portion has a thickness less than the length of the shortest edge of the laminate, and the second sintered portion has a thickness less than 0.1 mm.
6. The method of manufacturing a multilayer ceramic capacitor as claimed in claim 1, wherein, when a plurality of first ceramic films on which the additional layers are printed are laminated, the additional layers at corresponding positions on each first ceramic film are aligned one by one in the laminating direction.
7. The method of producing a multilayer ceramic capacitor as claimed in claim 1, wherein in the step (9), the sintered compact is made to completely surround the outermost laminated body when the laminated body and the sintered compact are mixedly placed on the setter plate.
8. A multilayer ceramic capacitor produced by the production method according to any one of claims 1 to 7.
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| JPH08316086A (en) * | 1995-05-19 | 1996-11-29 | Murata Mfg Co Ltd | Laminated ceramic electronic component |
| JP2000269074A (en) * | 1999-03-19 | 2000-09-29 | Taiyo Yuden Co Ltd | Multilayer ceramic capacitor and manufacture thereof |
| KR20120077318A (en) * | 2010-12-30 | 2012-07-10 | 삼성전기주식회사 | Nano composite powder for inner electrode of multi layer ceramic electronic device and fabricating method thereof |
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| CN105632758A (en) * | 2014-10-30 | 2016-06-01 | 陕西盛迈石油有限公司 | Method for sintering ceramic substrate of ceramic capacitor |
| CN104774005B (en) * | 2015-03-31 | 2017-05-17 | 洛阳理工学院 | Low-temperature sintered lead-free microwave dielectric ceramic and preparation method thereof |
| CN104952619B (en) * | 2015-06-18 | 2017-08-08 | 广东风华高新科技股份有限公司 | The preparation method of multilayer ceramic capacitor |
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