阅读说明：本技术 一种陶瓷材料、陶瓷浆料和多层片式陶瓷电容器 (Ceramic material, ceramic slurry and multilayer chip ceramic capacitor ) 是由 宋俊武 马艳红 邱基华 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种陶瓷材料、陶瓷浆料和多层片式陶瓷电容器。本发明陶瓷材料包括AQO-(3)和M组分,其中,A为Ba、Ca、Sr中的至少一种,Q为Ti、Zr、Hf中的至少一种,M组分为KAlSi-(2)O-(6)、ZrW-(2)O-(8)、HfW-(2)O-(8)中的至少一种,M组分的摩尔量为AQO-(3)摩尔量的0.3～3.6％。本发明陶瓷材料中添加特定用量的热致收缩材料M组分,能很好地改善陶瓷胚体与镍电极收缩率失配的问题,从而很好地改善MLCC产品分层开裂的问题。(The invention discloses a ceramic material, ceramic slurry and a multilayer chip ceramic capacitor. The ceramic material of the invention comprises AQO 3 And M component, wherein A is at least one of Ba, Ca and Sr, Q is at least one of Ti, Zr and Hf, and M component is KAlSi 2 O 6 、ZrW 2 O 8 、HfW 2 O 8 At least one of (a) and (b), the molar amount of the M component being AQO 3 0.3 to 3.6% by mole. The specific amount of the thermally induced shrinkage material M component is added into the ceramic material, so that the problem of mismatch of the shrinkage rates of the ceramic blank and the nickel electrode can be well solved, and the problem of delamination and cracking of an MLCC product can be well solved.)

1. A ceramic material comprising an M component and a main component AQO₃Wherein, in the step (A),a is at least one of Ba, Ca and Sr, Q is at least one of Ti, Zr and Hf, and M component is KAlSi₂O₆、ZrW₂O₈、HfW₂O₈At least one of (a) and (b), the molar amount of the M component being AQO₃0.3 to 3.6% by mole.

2. The ceramic material of claim 1 wherein the molar amount of said M component is AQO₃1.6 to 2.8% by mole.

3. The ceramic material according to claim 1 or 2, further comprising an X component, an R component and a Z component, wherein the X component is a compound of at least one element selected from Mg, La, Sm, Dy, Ho, Er, Y, Eu, Gd, Tm, Yb; the component R is a compound of at least one element of V, Mn, Cr, Co and Fe; the Z component is a compound of at least one element of Si, Ba, B, Zn, Al and Li; preferably, the X component, the R component and the Z component are all oxygen-containing compounds; more preferably, the X component, the R component and the Z component are all at least one of oxide, carbonate and hydroxide.

4. The ceramic material of claim 3, wherein the molar amount of the X component is AQO₃0.4-2.2% of molar weight, and the molar weight of the R component is AQO₃0.08-0.4% of molar weight, and the molar weight of the Z component is AQO₃0.5 to 4.5% by mole.

5. The ceramic material of claim 3, wherein the Z component is a glass frit.

6. The ceramic material of claim 1 or 2, wherein a is Ba and Q is Ti.

7. A ceramic slurry comprising the ceramic material according to any one of claims 1 to 6.

8. A multilayer chip ceramic capacitor comprising a ceramic dielectric and a nickel internal electrode, said ceramic dielectric consisting essentially of the ceramic material according to any one of claims 1 to 6.

9. The multilayer chip ceramic capacitor according to claim 8, wherein the nickel inner electrode comprises metallic nickel and a ceramic shrinkage inhibitor, and the mass ratio of the metallic nickel to the ceramic shrinkage inhibitor is 3.5: 1-7: 1, preferably 5: 1.

10. The multilayer chip ceramic capacitor as claimed in claim 9, wherein the ceramic shrinkage inhibitor is a nanoparticle having a composition corresponding to AQO which is a main component of the ceramic material₃The same is true.

Technical Field

The invention belongs to the technical field of ceramic capacitor materials, and relates to a ceramic material, ceramic slurry and a multilayer chip ceramic capacitor.

Background

A multilayer chip ceramic capacitor (MLCC) is an integral body, also called a monolithic structure, formed by stacking and sintering electrode materials and ceramic green bodies in a multilayer staggered manner. The delamination cracking is an important defect which influences the performance and the use of the ceramic capacitor product. During the sintering process of the ceramic green body and the nickel electrode layer, the shrinkage rate of the nickel electrode layer is usually larger than that of the ceramic green body and is shrunk before the ceramic green body, and the difference of the shrinkage rates can cause stress in the MLCC product and further cause cracking between the ceramic body and the electrode, so that the difference of the temperature range of material shrinkage and the shrinkage rate caused by temperature change is the root cause of shrinkage rate mismatch and delamination.

Aiming at the problem of layered cracking of MLCC products, the method improved from the formulation angle at present mainly comprises the steps of adding ceramic powder into nickel slurry as a co-material, and using the ceramic powder as a shrinkage inhibitor to reduce the shrinkage of a nickel electrode and improve the shrinkage matching property of the nickel electrode and a ceramic body, but after the improvement of the method, the shrinkage of the nickel electrode is still larger than that of the ceramic body, and the risk of layered cracking still exists after sintering.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a ceramic material, a ceramic slurry and a multilayer chip ceramic capacitor, wherein a specific amount of a specific type of thermal shrinkage material is added into the ceramic material, so that the problem of mismatch of sintering shrinkage rates of a ceramic blank and a nickel electrode can be well improved, and the problem of delamination cracking of an MLCC product is well improved.

To achieve the above object, in a first aspect, the present invention provides a ceramic material comprising an M component and a bulk component AQO₃Wherein A is at least one of Ba, Ca and Sr, Q is at least one of Ti, Zr and Hf, and M component is KAlSi₂O₆、ZrW₂O₈、HfW₂O₈At least one of (a) and (b), the molar amount of the M component being AQO₃0.3 to 3.6% by mole.

Preferably, the molar amount of the M component is AQO₃1.6 to 2.8% by mole.

Preferably, the ceramic material also comprises an X component, an R component and a Z component, wherein the X component is a compound of at least one element of Mg, La, Sm, Dy, Ho, Er, Y, Eu, Gd, Tm and Yb; the component R is a compound of at least one element of V, Mn, Cr, Co and Fe; the Z component is a compound of at least one element of Si, Ba, B, Zn, Al and Li. Preferably, the X component, the R component and the Z component are all oxygen-containing compounds; more preferably, the X component, the R component and the Z component are all at least one of oxide, carbonate and hydroxide.

Preferably, the molar amount of the X component is AQO₃0.4-2.2% of molar weight, and the molar weight of the R component is AQO₃0.08-0.4% of molar weight, and the molar weight of the Z component is AQO₃0.5 to 4.5% by mole.

Preferably, the Z component is a glass frit.

Preferably, a is Ba and Q is Ti.

In a second aspect, the present invention provides a ceramic material comprising the above ceramic material.

In a third aspect, the present invention provides a multilayer chip ceramic capacitor comprising a ceramic dielectric and a nickel internal electrode, the ceramic dielectric being mainly composed of the above ceramic material.

Preferably, the nickel inner electrode comprises metal nickel and a ceramic shrinking inhibitor, and the mass ratio of the metal nickel to the ceramic shrinking inhibitor is 3.5: 1-7: 1, and is further preferably 5: 1.

Preferably, the ceramic shrinkage inhibitor is nano-particle and has a composition with the main component AQO in the ceramic material₃The same is true.

Compared with the prior art, the invention has the beneficial effects that: according to the invention, a certain amount of thermal shrinkage material is added into the ceramic material of the MLCC, so that in the co-firing process of the nickel electrode material and the ceramic blank, the characteristic of volume shrinkage caused by temperature rise of the thermal shrinkage material can be utilized, the ceramic blank can generate an additional shrinkage effect, and the effect of shrinkage in advance can be achieved, so that the problem that the shrinkage of a nickel layer is large and the shrinkage of the ceramic blank lags is solved, namely the condition that the shrinkage of the ceramic blank is mismatched with that of the nickel electrode is improved, and the problem of layered cracking of the MLCC product is solved.

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples. It will be understood by those skilled in the art that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the examples, the experimental methods used were all conventional methods unless otherwise specified, and the materials, reagents and the like used were commercially available without otherwise specified.

Herein, AQO₃Refers to a perovskite structure compound of element a and element Q.

In order to solve the technical problem that the cracking between the ceramic medium and the nickel inner electrode occurs in the obtained MLCC product due to the shrinkage rate difference between the ceramic blank and the nickel inner electrode in the sintering process, a certain amount of specific thermal shrinkage material is added into the formula of the ceramic blank, the ceramic blank generates an additional shrinkage effect by utilizing the characteristic that the temperature of the thermal shrinkage material is increased and the volume is shrunk, and the effect of shrinking in advance is achieved, so that the problem that the shrinkage rate of the nickel inner electrode is large and the shrinkage of the ceramic blank is lagged is solved, namely the problem that the shrinkage rate of the ceramic blank is mismatched with that of the nickel inner electrode is solved, and the problem of the layered cracking of the MLCC product is solved. Specifically, the present invention provides a ceramic material comprising an M component and a bulk component AQO₃Wherein A is at least one of Ba, Ca and Sr, Q is at least one of Ti, Zr and Hf, and M component is KAlSi₂O₆、ZrW₂O₈、HfW₂O₈At least one of (a) and (b), the molar amount of the M component being AQO₃0.3 to 3.6% by mole. Wherein, AQO₃Is the main component, and the M component is a heat-induced shrinkage material.

If the molar amount of the M component is less than AQO₃0.3 percent of the molar weight, and the addition amount of the thermal shrinkage material is too small, so that the shrinkage matching property between the nickel inner electrode and the ceramic blank is not obviously improved, and the problem of MLCC delamination and cracking is not obviously improved. If the molar amount of the M component is greater than AQO₃3.6% of the molar weight, because the delamination cracking of the MLCC is related to the shrinkage matching between the nickel inner electrode and the ceramic body in the sintering temperature rise processIn the subsequent cooling process, the thermal expansion coefficients of the nickel inner electrode and the ceramic blank are different, the thermal expansion coefficient of the metal nickel is higher than that of the ceramic blank, and in the cooling process, the thermally induced shrinkage material generates additional expansion, so that the difference of the thermal expansion coefficients between the metal nickel and the ceramic blank is further aggravated, and the lamination cracking ratio of the MLCC is increased. In order to improve the problem of MLCC delamination cracking, the molar weight of the M component is selected to be AQO₃0.3 to 3.6% by mole. Preferably, the molar amount of the M component is AQO₃The molar weight is 1.6-2.8% so as to better improve the problem of MLCC delamination cracking.

The addition of different compositions and different amounts of the heat-shrinkable material can negatively affect the electrical properties of the MLCC. In order to improve TCC (cross-section resistance) and K value (namely dielectric constant) of MLCC, an X component, an R component and a Z component can be added into the ceramic material, wherein the X component is a compound of at least one element of Mg, La, Sm, Dy, Ho, Er, Y, Eu, Gd, Tm and Yb; the component R is a compound of at least one element of V, Mn, Cr, Co and Fe; the Z component is a compound of at least one element of Si, Ba, B, Zn, Al and Li. Preferably, the X component, the R component and the Z component are all oxygen-containing compounds; more preferably, the X component, the R component and the Z component are all at least one of oxide, carbonate and hydroxide.

In some preferred embodiments, the molar amount of the X component is AQO₃0.4-2.2% of the molar amount, and the molar amount of the R component is AQO₃0.08-0.4% of the molar weight, and the molar weight of the Z component is AQO₃0.5 to 4.5% by mole. When the X component, the R component and the Z component are used in the specific amount, the TCC performance index of the MLCC is within the range of +/-15%, and the dielectric constant of the product meets the use requirement.

In some preferred embodiments, the Z component is a glass frit to facilitate ceramic sintering densification.

In some preferred embodiments, a is Ba and Q is Ti.

The ceramic material of the present invention can be used for preparing ceramic slurry of MLCC, i.e. the ceramic slurry comprises a solvent and the ceramic material of the present invention. The type and the amount of the solvent are not particularly required, and the type and the amount of the solvent commonly used in the field can be selected, for example, the type of the solvent can be at least one of toluene, absolute ethyl alcohol, isopropyl alcohol and the like, and for example, the amount of the solvent can be 90-130 wt% of the solvent/ceramic powder.

An auxiliary agent such as a binder and a plasticizer may be added to the ceramic slurry as necessary. The type and the amount of the binder are not particularly required, and the type and the amount of the binder commonly used in the field can be selected, for example, the type of the binder can be selected from at least one of PVB (polyvinyl butyral), PVA (polyvinyl alcohol), and the like, and the amount of the binder can be selected from 8-10 wt% of the binder/ceramic powder; the type and amount of the plasticizer are not particularly required, and the type and amount of the plasticizer commonly used in the field can be selected, for example, the type of the plasticizer can be selected to be at least one of DOP, DBP and the like, and the amount of the plasticizer can be selected to be 2.5-3.5 wt% of the plasticizer/ceramic powder.

The ceramic material can be used for preparing MLCC, namely the MLCC comprises a ceramic medium and a nickel inner electrode, wherein the ceramic medium mainly comprises the ceramic material.

In some embodiments, the ceramic inner electrode comprises metallic nickel and a ceramic shrinking inhibitor, and the mass ratio of the metallic nickel to the ceramic shrinking inhibitor is 3.5: 1-7: 1. The ceramic shrinkage inhibitor is added into the nickel inner electrode, so that the shrinkage matching difference between the ceramic green body and the nickel inner electrode in sintering can be relieved, and the effect of better improving cracking can be achieved by using the M component on the basis. Excessive addition of the ceramic shrinkage inhibitor can affect the electrical properties of the product because the ceramic shrinkage inhibitor diffuses into the ceramic dielectric layer during sintering and interacts with the bulk component AQO in the dielectric layer₃The materials are sintered together, so that the abnormal growth of crystal grains can be caused due to excessive addition amount, and the electrical property deterioration is influenced; the ceramic shrinkage inhibitor is added too little, and the shrinkage matching effect of sintering of the ceramic green body and the nickel inner electrode is relieved from being deteriorated, so that the mass ratio of the metal nickel to the ceramic shrinkage inhibitor is 3.5: 1-7: 1, and the mass ratio of the metal nickel to the ceramic shrinkage inhibitor is preferably 5: 1.

The ceramic shrinkage inhibitor may be selected from nanoparticles, and the composition is selected from the group consisting of AQO₃The same is true. The type of ceramic shrinkage inhibitor and the main component AQO in the ceramic material used₃The same, to prevent the addition of other substances from having a large influence on the electrical properties of the MLCC.

In some embodiments, the method of making the MLCC comprises the steps of:

(1) AQO will be mixed₃Mixing the X component, the R component, the Z component, the M component, an adhesive, a plasticizer and a solvent to prepare ceramic slurry, wherein the Z component is glass frit;

(2) preparing the ceramic slurry obtained in the step (1) into a ceramic green film;

(3) printing nickel slurry containing a ceramic shrinkage inhibitor on the ceramic green film obtained in the step (2), then, cross-laminating to obtain a laminated sheet, pressing and forming the laminated sheet, cutting the laminated sheet into a required size, then, removing glue, and sintering to obtain a laminated chip;

(4) and grinding the corners and edges of the laminated chips by a roller to form round corners, fully exposing the sintered and contracted nickel electrodes to obtain a laminated body, coating copper paste on two end faces of the laminated body, sintering and electroplating to obtain the MLCC finished product.

In the step (1), the raw materials can be selected from powder states, wherein the Z-component glass powder can be prepared by the following method: the Z component of the glass material is heated, melted, quenched into glass fragments, and then ground or crushed into glass powder.

In the step (2), the thickness of the ceramic green film can be selected according to the requirement, such as 1-10 μm, and further such as 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, and the like.

In the step (3), the processing method of the compression molding can be selected from isostatic pressing and the like, and the technological conditions of the isostatic pressing can be selected according to the actual conditions, such as 100Mpa/80 ℃ and the like; the glue discharging can be carried out in a protective gas atmosphere, and the glue discharging temperature can be selected from 350-450 ℃ and the like; the sintering temperature can be selected according to the formula, such as in the range of 1000-1280 ℃.

In the step (4), the copper burning can be selected from N₂+H₂+H₂The reaction is carried out under an O atmosphere, and the temperature can be selected from 700-900 ℃, such as 700 ℃, 800 ℃, 900 ℃.

In the research process, the inventors perform performance measurement on the prepared multilayer chip ceramic capacitor by adopting the following test method:

(1) dielectric constant: the capacity value was measured in accordance with GB/T21042-2007, and the dielectric constant was calculated from C-0.00884 XK (N-1). times.S/d, where C is the capacity value (in pF), K is the relative dielectric constant, N is the number of stacked layers, and S is the electrode area (in mm) of the sintered product²) D is the thickness (in mm) of the dielectric layer of the sintered product;

(2) dielectric loss: testing according to GB/T21042-2007;

(3) TCC (rate of temperature change of capacitance): testing according to GB/T21042-2007;

(4) the layering and cracking proportion is as follows: adhering the multilayer chip ceramic capacitor product on the foaming glue, and detecting the layering cracking proportion by using ultrasonic SAT.

And (4) qualified standard: the dielectric constant is more than or equal to 2800 and less than or equal to 4200, the dielectric loss is less than or equal to 7.0 percent, the TCC is more than or equal to-15 percent and less than or equal to +15 percent, and the delamination cracking proportion is less than or equal to 10 ppm.

Examples 1 to 9 and comparative examples 1 to 5

Examples 1 to 9 and comparative examples 1 to 5 respectively provide multilayer chip ceramic capacitors, and a method for manufacturing these ceramic capacitors includes the steps of:

(1) heating the Z component of the glass material in a crucible to 1380 ℃, melting, preparing glass fragments by a water-cooling quenching mode, and then ball-milling for 12 hours by a high-speed ball mill to prepare glassy state powder;

(2) mixing the glassy state powder obtained in the step (1) and BaTiO₃Uniformly mixing the powder, the X component powder, the R component powder, the M component powder, a PVB (polyvinyl butyral) adhesive, DOP (dioctyl phthalate), toluene and absolute ethyl alcohol, sanding and dispersing the mixture by using a sand mill to obtain ceramic slurry, casting the obtained ceramic slurry into a ceramic green film with the film thickness of 3 mu M by using a casting machine, wherein the components and the using amounts of the glassy state powder, the X component powder, the R component powder and the M component powder are shown in Table 1, and BaTiO₃The mass ratio of the powder to the PVB adhesive to the DOP to the toluene to the absolute ethyl alcohol is 100:9.2:2.8:38.4: 81.6;

(3) printing nickel slurry (metallic nickel/ceramic) containing ceramic shrinking inhibitor on the ceramic green film obtained in the step (2)The mass ratio of the shrinkage-resistant agent is 5:1, and the ceramic shrinkage-resistant agent is BaTiO₃Nano particles), obtaining a laminated sheet through staggered lamination of a given number of sheets, and cutting the laminated sheet into a specified size through isostatic pressing at 100Mpa/80 ℃;

(4) through N₂After the glue discharging treatment under the environment condition of 400 ℃, carrying out heat preservation for 2h at 1220 ℃ for sintering to obtain a laminated chip;

(5) then, the corners and edges of the laminated chips are rounded by roller grinding, the sintered and contracted nickel electrodes are fully exposed, copper paste is coated on two end faces of the laminated chip, and the copper paste is heated at 800 ℃ under N₂+H₂+H₂Sintering in O atmosphere, and electroplating to obtain the final product.

TABLE 1

The composition and amount of the X component, the R component, the Z component and the M component in each example and comparative example are described by taking example 1 as an example. In example 1, the X component is composed of MgO and Dy₂O₃Composition in which the molar amount of MgO is BaTiO in the ceramic slurry₃0.8% by mole of Dy₂O₃The molar weight of the component (a) is BaTiO in the ceramic slurry₃0.8% of molar weight; r component is composed of V₂O₅MnO and Cr₂O₃Composition of, wherein V₂O₅The molar weight of the component (a) is BaTiO in the ceramic slurry₃0.03% of molar weight, and the molar weight of MnO is BaTiO in the ceramic slurry₃0.03% by mole of Cr₂O₃The molar weight of the component (a) is BaTiO in the ceramic slurry₃0.02% of molar weight; the Z component consists of BaCO₃、ZnO、B₂O₃And SiO₂Composition of, wherein BaCO₃The molar weight of the component (a) is BaTiO in the ceramic slurry₃0.3 percent of the molar weight, and the molar weight of ZnO is BaTiO in the ceramic slurry₃0.1% by mol, B₂O₃The molar weight of the component (a) is BaTiO in the ceramic slurry₃0.3% by mol of SiO₂In a molar amount of BaTiO₃0.8% of molar weight; m component is made of KAlSi₂O₆Composition, KAlSi₂O₆The molar weight of the component (a) is BaTiO in the ceramic slurry₃0.3% of the molar amount.

The results of the performance test of the multilayer chip ceramic capacitors obtained in the respective examples and comparative examples are shown in Table 2.

TABLE 2

The use level of the M component (namely the molar weight of the M component is BaTiO) is comprehensively considered₃The percentage of the molar mass) is 0.3-3.6 mol%, the layering cracking proportion is low, and various electrical properties meet the use requirements. In comparative examples 1 and 3, the proportion of delamination cracks increased to more than 10ppm and the dielectric constant of the product was low due to excessive addition of the M component. In comparative examples 2 and 4, the addition of the M component was too small, and the improvement of the delamination cracking was not significant. In comparative example 5, the delamination cracking is particularly obvious because no M component is added, and the proportion is as high as 16ppm, which seriously affects the practical production application.

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.