A ceramic material, a ceramic slurry, and a preparation method and application thereof

Abstract

The application relates to a ceramic material, a ceramic slurry and a preparation method and application thereof, and belongs to the technical field of capacitors. The ceramic material comprises a first type of ceramic solid solution (A 1 x A 2 y B 1 z B 2 w O3), a second type of ceramic solid solution (A 3 B 3 α B 4 β B 5 γ O3), MnO2, V2O5 and a sintering aid (at least comprising CaO, Li2O and SiO2). The ceramic material can make the ceramic capacitor have high dielectric constant and high reliability, and the temperature characteristic meets the EIA standard X7R characteristic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of capacitors, in particular to a ceramic material, a ceramic slurry and a preparation method and application thereof. BACKGROUND

[0002] Chip multilayer ceramic capacitors (MLCC) have the advantages of high precision, high integration, low power consumption, etc., and are widely used in consumer electronics, automobiles, home appliances, new energy and other fields. In recent years, with the miniaturization and high performance of electronic devices, there is an increasing demand for miniaturized and high-capacity multilayer ceramic capacitors. At present, miniaturization and high-capacity are mainly achieved by thinning the dielectric layer of the MLCC to increase the number of layers. Ceramic powder is a key material for preparing dielectric layers, and currently widely used is barium titanate ceramic powder. Barium titanate (BaTiO3) is a typical ABO3 type perovskite structure, and the Curie temperature point of pure barium titanate is about 125℃. The dielectric constant of pure barium titanate with a particle size of about 200nm at room temperature is only about 1700, which is difficult to meet the use requirements of thin film type high-capacity products. Although the room temperature dielectric constant of barium titanate can be increased to more than 4000 through different synthesis methods and control of grain size, there are still defects such as high temperature coefficient, high dielectric loss and poor direct current bias characteristics. SUMMARY

[0003] The present application aims to overcome the deficiencies of the prior art and provide a ceramic material and a preparation method and application thereof.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0005] In a first aspect, the present application provides a ceramic material, which comprises a first type of ceramic solid solution, a second type of ceramic solid solution, MnO2, V2O5 and a sintering aid;

[0006] The chemical general formula of the first type of ceramic solid solution is A 1 x A 2 y B 1 z B 2 w O3,

[0007] Wherein 0.01≤x≤0.1, 0.005≤w≤0.02; A 1 is at least one of La, Gd, Pr, Sm and Ce, A 2 is Ba, B 1 is Ti, B 2 is Mg;

[0008] The chemical general formula of the second type of ceramic solid solution is A3 B 3 α B 4 β B 5 γ O3,

[0009] wherein 0.005≤α≤0.05, 0.001≤β≤0.005; A 3 is Ba, B 3 is at least one of Er, Tm, Yb, Lu, Sc, B 4 is Mg, B 5 is Ti;

[0010] The sintering aid at least comprises CaO, Li2O and SiO2.

[0011] The present application combines a kind of ceramic solid solution formed by large ionic radius rare earth ions and magnesium ions and barium titanate, two kinds of ceramic solid solution formed by small ionic radius rare earth ions and magnesium ions and barium titanate and specific sintering aid, and collocates MnO2 and V2O5 to form ceramic material, by regulating the amount of large ionic radius rare earth ions and magnesium ions in the first kind of ceramic solid solution, the amount of small ionic radius rare earth ions and magnesium ions in the second kind of ceramic solid solution, and the content of the first kind of ceramic solid solution and the second kind of ceramic solid solution in the ceramic material, so that the ceramic capacitor with the ceramic material as the ceramic dielectric raw material has high dielectric constant and high reliability, and temperature characteristic meets EIA standard X7R characteristic.

[0012] The weight percentage of the first kind of ceramic solid solution and the second kind of ceramic solid solution in the ceramic material of the present application plays a key role in the dielectric constant, temperature characteristic and reliability of the ceramic capacitor; wherein, the B site (i.e. Ti site) of BaTiO3 is replaced by rare earth ions, which will increase the volume of BaTiO3 unit cell in grain shell, and make the volume of grain shell expand relatively to the grain core in the process of sintering temperature reducing to room temperature, produce tension effect to the grain core, and then promote the Curie temperature (Tc) point of BaTiO3 grain core to rise; and the A site (i.e. Ba site) of BaTiO3 is replaced by rare earth ions, which will produce pressure stress effect to BaTiO3 grain core, and then make its Curie temperature point to reduce.

[0013] Large ionic radius rare earth ions tend to substitute A sites of BaTiO3, which causes the Tc point of the ceramic solid solution to move to low temperature, thus improving the dielectric constant of the ceramic solid solution at room temperature. However, excessive A site substitution will cause abnormal grain growth and poor temperature stability of the ceramic capacitor. Small ionic radius rare earth ions tend to substitute B sites of BaTiO3, which causes the Tc point of the ceramic solid solution to move to high temperature, thus improving the TCC of the ceramic capacitor. In addition, due to the low diffusion rate of small radius rare earth ions, they tend to be non-uniformly distributed in the grain boundary and grain shell region of the ceramic solid solution, thus better preventing grain growth to increase the insulation breakdown time and improve the reliability of the ceramic capacitor.

[0014] The rare earth ions in the first type of ceramic solid solution or the second type of ceramic solid solution exist in the grain boundary and the grain of the ceramic solid solution, thus improving the life characteristics of the ceramic capacitor during high temperature loading to improve its reliability. However, when the content of rare earth ions in the ceramic solid solution is too low, it is difficult to sufficiently improve the reliability of the ceramic capacitor; and when the content of rare earth ions in the ceramic solid solution is too high, it will cause the sintering characteristics of the ceramic solid solution to deteriorate during sintering, which will instead reduce the reliability of the ceramic capacitor.

[0015] For the first type of ceramic solid solution A 1 x A 2 y B 1 z B 2 w O3, the large radius rare earth ions A 1 diffuse faster in BaTiO3, which can easily cause grain growth; at the same time, it will also diffuse deeply into the BaTiO3 grain, thus destroying the formation of the grain shell, and eventually becoming a chemically homogeneous grain (i.e. unable to form a core-shell structure). Therefore, more magnesium ions are needed to suppress the growth of BaTiO3 grains and form a complete core-shell structure for large radius rare earth ions than for small radius rare earth ions.

[0016] It is found that A 1 x A 2 y B 1 z B 2 wSuitable value range of x in O3 is 0.01≤x≤0.1, when x<0.01, it is not conducive to solid solution of rare earth ions into BaTiO3 to form complete shell, thereby accelerating deterioration of ceramic capacitor life; when x>0.1, too much solid solution of rare earth ions into BaTiO3, thereby leading to decrease of dielectric constant of ceramic solid solution and decrease of sintering activity. Alternatively, the above x can be specifically 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09.

[0017] A 1 x A 2 y B 1 z B 2 w Suitable value range of w in O3 is 0.005≤w≤0.02, when w<0.005, diffusion of rare earth ions into BaTiO3 cannot be inhibited, thereby leading to failure of ceramic solid solution to form complete core-shell structure, and further leading to deterioration of TCC of ceramic capacitor; when w>0.02, too much magnesium content strongly inhibits grain growth, which is not conducive to sintering densification of ceramic solid solution. Alternatively, the above w can be specifically 0.006, 0.007, 0.008, 0.009, 0.01, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019.

[0018] In addition, A 1 x A 2 y B 1 z B 2 w In O3, z and w satisfy: z+w=1, and x and y satisfy: 0.96≤x+y≤1.015; alternatively, value range of y can be 0.86-1.005, and can be specifically 0.865, 0.895, 0.915, 0.93, 0.935, 0.94, 0.945, 0.955, 0.98, 0.985, 0.99, 0.995, 1; value range of z can be 0.98-0.995, and can be specifically 0.982, 0.984, 0.986, 0.988, 0.99, 0.992, 0.994.

[0019] For the second type of ceramic solid solution A 3 B 3 α B 4 β B 5 γO3, small ionic radius rare earth ions B 3 And magnesium ions are substituted for B-site of BaTiO3 to become acceptor ions, the addition of acceptor ions can improve the resistance to reduction, but excessive acceptor ions will form a large number of oxygen vacancies, and the electric migration of these charged oxygen vacancies under high temperature and high pressure will lead to insulation decline, and thus the reliability of ceramic capacitors deteriorates.

[0020] Research found that A 3 B 3 α B 4 β B 5 γ The suitable value range of α in O3 is 0.005≤α≤0.05, when α<0.005, it is not conducive to the formation of a complete shell of ceramic solid solution, and small radius rare earth ions are difficult to effectively solid solution into BaTiO3, and the improvement effect of TCC of ceramic capacitors is not good; when α>0.05, excessive acceptor ions will form a large number of oxygen vacancies, which will lead to the deterioration of the insulation resistance of ceramic capacitors under high temperature and high pressure, and the reliability becomes poor. Alternatively, the above α can be specifically 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045.

[0021] A 3 B 3 α B 4 β B 5 γ The suitable value range of β in O3 is 0.001≤β≤0.005, when β<0.001, the diffusion of rare earth ions into BaTiO3 cannot be inhibited, which leads to the inability of ceramic solid solution to form a complete core-shell structure, and thus the TCC of ceramic capacitors deteriorates; when β>0.005, the diffusion of magnesium ions and small ionic radius rare earth ions in BaTiO3 is relatively slow, and since magnesium ions diffuse into BaTiO3 before small radius rare earth ions during solid solution, excessive magnesium ions will lead to the inability of small radius rare earth ions to completely solid solution into BaTiO3, and thus the improvement effect of TCC of ceramic capacitors is not good. Alternatively, the above β can be specifically 0.002, 0.003, 0.004.

[0022] In addition, the above A 3 B 3 α B 4 β B 5 γThe α, β and γ in O3 satisfy: (1+α) / (β+γ)=1.006-1.090; optionally, the value range of γ is 0.96-0.9958, and specifically, γ can be 0.961, 0.962, 0.969, 0.977, 0.99, 0.991, 0.9915, 0.992, 0.9938.

[0023] Optionally, the weight percentage of the first type of ceramic solid solution in the ceramic material is 50%-85%, and the weight percentage of the second type of ceramic solid solution is 12%-35%; the sintering aid at least includes CaO, Li2O and SiO2, and can further include an oxide of aluminum, an oxide of boron and the like.

[0024] As a preferred embodiment of the ceramic material, the ceramic material includes the following components by weight percentage: 50%-85% of the first type of ceramic solid solution, 12%-35% of the second type of ceramic solid solution, 0.1%-5% of MnO2, 0.1%-3% of V2O5 and 2.4%-15% of the sintering aid.

[0025] Optionally, the weight percentage of the first type of ceramic solid solution can be specifically 55%, 57%, 60%, 63%, 65%, 67%, 70%, 72%, 75%, 78% or 80%; the weight percentage of the second type of ceramic solid solution can be specifically 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32% or 34%; the weight percentage of MnO2 can be specifically 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% or 4.5%; the weight percentage of V2O5 can be specifically 0.3%, 0.6%, 0.9%, 1.2%, 1.5%, 1.8%, 2.1%, 2.4% or 2.7%; and the weight percentage of the sintering aid can be specifically 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13% or 14%.

[0026] As a preferred embodiment of the ceramic material, the ceramic material includes the following components by weight percentage: 60%-75% of the first type of ceramic solid solution, 18%-30% of the second type of ceramic solid solution, 0.5%-3.5% of MnO2, 0.8%-2% of V2O5 and 6%-10% of the sintering aid.

[0027] More preferably, the ceramic material includes the following components by weight percentage: 70% of the first type of ceramic solid solution, 20% of the second type of ceramic solid solution, 1.5% of MnO2, 1.2% of V2O5 and 7.3% of the sintering aid.

[0028] As a preferred embodiment of the ceramic material, the CaO accounts for 10% to 30% of the total weight of the sintering aid, and the Li2O accounts for 10% to 30% of the total weight of the sintering aid.

[0029] The CaO in the sintering aid has the function of regulating A(Ca, Ba) / B(Ti), and the appropriate increase of the ratio of A / B is conducive to the increase of the insulation resistance of the ceramic capacitor, but the excessive ratio of A / B will result in the excessively high sintering temperature of the ceramic material; and the Li2O and SiO2 are easy to form liquid phase in the sintering process of the ceramic material, and can reduce the sintering temperature. When the weight percentage of CaO in the sintering aid is excessively large, the sintering temperature of the ceramic material is excessively high, and when the weight percentage is excessively small, the CaO is difficult to regulate A(Ca, Ba) / B(Ti); when the weight percentage of Li2O in the sintering aid is excessively small, the sintering characteristics of the ceramic material will be poor, and when the weight percentage is excessively large, the Li2O is easy to react with Mg in the ceramic solid solution to generate secondary phase.

[0030] Preferably, the SiO2 in the sintering aid accounts for 40% to 80% of the total weight of the sintering aid, and when the weight percentage of SiO2 is within the range, the sintering temperature of the ceramic material can be better reduced, and the generation of secondary phase of the ceramic material can be more effectively prevented.

[0031] Optionally, the weight percentage of CaO in the sintering aid can be 15%, 20%, or 25%, the weight percentage of Li2O can be 15%, 20%, or 25%, and the weight percentage of SiO2 can be 45%, 50%, 55%, 60%, 65%, 70%, or 75%.

[0032] As a preferred embodiment of the ceramic material, the ceramic solid solution is prepared by the following preparation method: the stoichiometric ratio of each element in the chemical formula A 1 x A 2 y B 1 z B 2 w O3, the oxides of A 1 , the oxides of B 2 , and BaTiO3 are ball milled for 15 to 20 hours, and then baked at 1000 to 1050°C for 3 to 5 hours in an air atmosphere. Optionally, the ball milling time can be 16 hours, 17 hours, 18 hours, or 19 hours, the baking temperature can be 1010°C, 1020°C, 1030°C, or 1040°C, and the baking time can be 3.5 hours, 4 hours, or 4.5 hours.

[0033] As a preferred embodiment of the ceramic material, the second type of ceramic solid solution is prepared by the following method: mixing the first type of ceramic solid solution, MnO2, V2O5 and sintering aids according to the general formula A 3 B 3 α B 4 β B 5 γ O3, ball-milling oxides of B 3 , oxides of B 4 and BaTiO3 for 15-20 hours, and then baking at 1050-1100°C in air for 3-5 hours. Alternatively, the ball-milling time can be 16 hours, 17 hours, 18 hours, 19 hours, the baking temperature can be 1060°C, 1070°C, 1080°C, 1090°C, and the baking time can be 3.5 hours, 4 hours, 4.5 hours.

[0034] The ball-milling in the preparation method of the first type of ceramic solid solution or the second type of ceramic solid solution refers to wet ball-milling using a ball mill. In addition, the first type of ceramic solid solution or the second type of ceramic solid solution obtained by baking in the preparation method can be further wet ball-milled using a ball mill, the ball-milling time is 20-30 hours, and the ball-milling rate is 100-150 rpm.

[0035] In a second aspect, the present application provides a preparation method of the ceramic material, which comprises the following steps: mixing the first type of ceramic solid solution, the second type of ceramic solid solution, MnO2, V2O5 and sintering aids uniformly to obtain the ceramic material.

[0036] In a third aspect, the present application provides a ceramic slurry, which comprises a ceramic powder, an organic solvent and a binder, and the ceramic powder is the ceramic material.

[0037] As a preferred embodiment of the ceramic slurry, the weight percentage of the organic solvent relative to the ceramic powder is 80%-85%, and the weight percentage of the binder relative to the ceramic powder is 7%-9%.

[0038] As a preferred embodiment of the ceramic slurry, the organic solvent comprises at least one of toluene and ethanol, and the binder comprises at least one of polyvinyl butyral and polyacrylic acid.

[0039] As a preferred embodiment of the ceramic slurry, the ceramic slurry can be prepared by the following method: adding the ceramic powder, the organic solvent and the binder into a ball mill for wet mixing and dispersion to obtain the ceramic slurry; wherein the ball-milling time is about 40-50 hours, the ball-milling rate is 150-200 rpm, and the ball-milling medium is zirconia balls (2-4 mm in diameter, added in an amount of 10-12 times the mass of the ceramic powder).

[0040] In a fourth aspect, the present application provides a chip multilayer ceramic capacitor comprising a ceramic dielectric prepared from the ceramic slurry described above.

[0041] Compared with the prior art, the present application has the following advantages:

[0042] The present application combines a type of ceramic solid solution formed by large ionic radius rare earth ions and magnesium ions and barium titanate, a type II ceramic solid solution formed by small ionic radius rare earth ions and magnesium ions and barium titanate, and a specific sintering aid, and matches MnO2 and V2O5 to form a ceramic material. By adjusting the amount of large ionic radius rare earth ions and magnesium ions in the type I ceramic solid solution, the amount of small ionic radius rare earth ions and magnesium ions in the type II ceramic solid solution, and the content of the type I ceramic solid solution and the type II ceramic solid solution in the ceramic material, the ceramic capacitor using the ceramic material as the ceramic dielectric raw material has high dielectric constant and high reliability, and the temperature characteristics meet the EIA standard X7R characteristics. DETAILED DESCRIPTION

[0043] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below in combination with specific examples.

[0044] Other materials, reagents, etc. used in the examples and comparative examples can be obtained from commercial channels unless otherwise specified.

[0045] 1, a type of ceramic solid solution (A 1 x A 2 y B 1 z B 2 w O3, A 1 is a rare earth element, A 2 is Ba, B 1 is Ti, B 2 is Mg)

[0046] Table 1A 1 x A 2 y B 1 z B 2 w The type of rare earth element A 1 in O3 and the values of x, y, z and w

[0047] No. A 1 ]]> x y z w C1 La 0.01 1.005 0.98 0.02 C2 La 0.01 0.99 0.995 0.005 C3 La 0.01 1 0.985 0.015 C4 La 0.01 0.995 0.99 0.01 C5 La 0.02 0.98 0.99 0.01 C6 La 0.05 0.935 0.99 0.01 C7 La 0.1 0.86 0.99 0.01 C8 La 0.08 0.895 0.985 0.015 C9 La 0.02 0.985 0.985 0.015 C10 La 0.05 0.94 0.985 0.015 C11 La 0.1 0.865 0.985 0.015 C12 La 0.05 0.945 0.98 0.02 C13 La 0.05 0.93 0.995 0.005 C14 La 0.02 0.99 0.98 0.02 C15 La 0.06 0.915 0.995 0.005 C16 La 0.04 0.955 0.985 0.015 C17 La 0 1.015 0.985 0.015 C18 La 0.5 0.265 0.985 0.015 C19 La 0.01 0.985 1 0 C20 La 0.01 1.035 0.95 0.05 C21 Gd 0.05 0.94 0.985 0.015 C22 Pr 0.05 0.94 0.985 0.015 C23 Sm 0.05 0.94 0.985 0.015 C24 Ce 0.05 0.94 0.985 0.015

[0048] The preparation method of the above type I ceramic solid solution comprises the following steps:

[0049] The oxides of A 1 , the oxides of B 2 and BaTiO3 ceramic powder are mixed by wet ball milling for about 15 hours, dried, calcined at 1000°C in air for 4 hours, and then wet milled by a ball mill for about 20 hours (the speed of the ball mill is 110 rpm) to obtain a ceramic solid solution powder.

[0050] 2. The second type of ceramic solid solution (A 3 B 3 α B 4 β B 5 γ O3, A 3 is Ba, B 3 is a rare earth element, B 4 is Mg, and B 5 is Ti)

[0051] Table 2A 3 B 3 α B 4 β B 5 γ O3, the type of the rare earth element B 3 and the values of α, β and γ

[0052] No. B 3 ]]> α β γ E1 Lu 0.005 0.005 0.9938 E2 Lu 0.05 0.001 0.9620 E3 Lu 0.01 0.001 0.9920 E4 Lu 0.03 0.001 0.9770 E5 Lu 0.04 0.002 0.9690 E6 Lu 0.01 0.003 0.9910 E7 Lu 0.01 0.005 0.9900 E8 Lu 0.01 0.002 0.9915 E9 Lu 0.05 0.003 0.9610 E10 Lu 0.005 0.001 0.9958 E11 Lu 0.05 0.005 0.9600 E12 Lu 0 0.003 0.9985 E13 Lu 0.08 0.003 0.9385 E14 Lu 0.03 0 0.9775 E15 Lu 0.03 0.01 0.9725 E16 Tm 0.01 0.003 0.9910 E17 Yb 0.01 0.003 0.9910 E18 Er 0.01 0.003 0.9910 E19 Sc 0.01 0.003 0.9910

[0053] The method for preparing the second type of ceramic solid solution comprises the following steps:

[0054] The oxides of B 3 , the oxides of B 4 and BaTiO3 ceramic powder are mixed by wet ball milling for about 15 hours, dried, calcined at 1050°C in air for 4 hours, and then wet milled by a ball mill for about 25 hours (the speed of the ball mill is 110 rpm) to obtain a second type of ceramic solid solution powder.

[0055] 3. Sintering aid (aCaO-bLi2O-cSiO2, a is the weight percentage of CaO in the sintering aid, b is the weight percentage of Li2O in the sintering aid, and c is the weight percentage of SiO2 in the sintering aid)

[0056] Table 3 Weight percentage of CaO, Li2O and SiO2 in the sintering aid

[0057] No. a / ％ b / ％ c / ％ F1 10 10 80 F2 20 20 60 F3 30 30 40 F4 20 30 50 F5 15 15 70 F6 / 20 80 F7 5 30 65 F8 40 10 50 F9 20 / 80 F10 30 5 65 F11 10 40 50 F12 50 50 / F13 / / 100

[0058] The method for preparing the sintering aid comprises the following steps:

[0059] CaO, Li2O and SiO2 were mixed uniformly according to the proportions in Table 3 to obtain the sintering aid.

[0060] 4. Examples 1-38 and Comparative Examples 1-20

[0061] The formulations of the ceramic materials in Examples 1-9 and Comparative Examples 9-12 are shown in Table 4.

[0062] Table 4 Formulations of the ceramic materials in Examples 1-9 and Comparative Examples 9-12

[0063]

[0064]

[0065] Examples 10-38, Comparative Examples 1-8 and Comparative Examples 13-20

[0066] The ceramic materials in Examples 8-22, Comparative Examples 1-8 and Comparative Examples 13-38 are substantially the same as in Example 1 (i.e. each includes 70% of a first ceramic solid solution, 20% of a second ceramic solid solution, 1.5% of MnO2, 1.2% of V2O5 and 7.3% of a sintering aid, by weight percentage), except that the first ceramic solid solution, the second ceramic solid solution and the sintering aid are different, as shown in Table 5.

[0067] Table 5 Formulations of the ceramic materials in Examples 1-9, Comparative Examples 1-8 and Comparative Examples 9-12

[0068]

[0069]

[0070]

[0071] The method for preparing the ceramic material described above comprises the following steps: uniformly mixing the first ceramic solid solution, the second ceramic solid solution, MnO2, V2O5 and the sintering aid to obtain the ceramic material.

[0072] 5. Performance testing

[0073] (1) Ceramic slurry

[0074] The ceramic materials in Examples 1-38 and Comparative Examples 1-20 were mixed uniformly with an organic solvent (toluene, 85% by weight percentage relative to the ceramic powder) and a binder (polyvinyl butyral, 8% by weight percentage relative to the binder) to obtain a ceramic slurry.

[0075] The specific preparation method is as follows: ceramic powder, binder, organic solvent and ball milling medium (zirconia balls with a diameter of 2 mm are used as the ball milling medium, and the addition amount is 10 times the mass of the ceramic powder) are added into a ball mill and wet mixed and dispersed, the ball milling time is about 40 h, and the ball milling rate is 150 rpm, to prepare a uniform ceramic slurry.

[0076] (2) Multilayer ceramic capacitor

[0077] The preparation method of the multilayer ceramic capacitor comprises the following steps:

[0078] S1, the ceramic slurry is cast into a film with a thickness of 4 μm;

[0079] S2, the conductive slurry for internal electrodes mainly composed of base metal materials such as Ni is used to form a conductive film pattern on the surface of the film in S1 by screen printing, and the film with printed electrodes is laminated and formed, and is subjected to isostatic pressing and cutting to form a green body;

[0080] S3, the green body in S2 is heat treated in air (temperature is 200-280 ℃, time is 10-12 h) to remove the organic matter inside the green body; and then sintered at 1150-1200 ℃ for about 2-4 h (heating rate is 5-10 ℃ / min) in a strong reducing atmosphere (composed of H2-N2-H2O gas, oxygen partial pressure is 10 Pa) to obtain a ceramic body. -11

[0081] S4, copper external electrodes are covered on both ends of the ceramic body in S3 to obtain a multilayer ceramic capacitor.

[0082] (3) Dielectric constant, dielectric loss, reliability and temperature characteristic (TCC) test

[0083] The above multilayer ceramic capacitor is tested as follows, and the test results are shown in Table 7.

[0084] Table 6 Test content summary and its standard

[0085]

[0086]

[0087] Table 7 Performance test data

[0088]

[0089]

[0090]

[0091] ​As can be seen from the data in Table 7, the dielectric constant of the ceramic capacitors made using the ceramic material of this invention ranges from 2633 to 4082, all of which are greater than or equal to 2500; the dielectric loss ranges from 1.52% to 2.54%, all of which are less than or equal to 5%; the reliability is greater than or equal to 1000 hours, and the temperature change rate of the capacitor is within ±15% in the range of -55℃ to 125℃, which means that the ceramic capacitors have excellent performance.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A ceramic material, characterized in that, The ceramic materials include Class I ceramic solid solutions, Class II ceramic solid solutions, MnO2, V2O5, and sintering aids; The general chemical formula of the aforementioned type of ceramic solid solution is A 1 x A 2 y B 1 z B 2 w O3, Where 0.01≤x≤0.1, 0.005≤w≤0.02; A 1 A is at least one of La, Gd, Pr, Sm, and Ce. 2 for Ba,B 1 For Ti, B 2 It is Mg; The general chemical formula of the second type of ceramic solid solution is A. 3 B 3 α B 4 β B 5 γ O3, Where 0.005≤α≤0.05, 0.001≤β≤0.005; A 3 for Ba,B 3 B is at least one of Er, Tm, Yb, Lu, and Sc. 4 For Mg, B 5 For Ti; The sintering aids include at least CaO, Li2O and SiO2; Large-radius rare-earth ions and magnesium ions form a type of ceramic solid solution with barium titanate. Small-radius rare earth ions and magnesium ions form two types of ceramic solid solutions with barium titanate. The type of ceramic solid solution A 1 x A 2 y B 1 z B 2 w In O3, z and w satisfy: z + w = ​​1; The type of ceramic solid solution A 1 x A 2 y B 1 z B 2 w In O3, x and y satisfy: 0.96 ≤ x + y ≤ 1.015; The second type of ceramic solid solution A 3 B 3 α B 4 β B 5 γ α, β and γ in O3 satisfy: (1+α) / (β+γ)=1.006~1.090; The ceramic material comprises, by weight, 50%–85% of a first-order ceramic solid solution, 12%–35% of a second-order ceramic solid solution, 0.1%–5% of MnO2, 0.1%–3% of V2O5, and 2.4%–15% of sintering aids. The CaO accounts for 10% to 30% of the total weight of the sintering aids, and the Li2O accounts for 10% to 30% of the total weight of the sintering aids.

2. The ceramic material as described in claim 1, characterized in that, The aforementioned ceramic solid solution is prepared by the following method: according to chemical formula A 1 x A 2 y B 1 z B 2 w The stoichiometric ratios of the elements in O3, and A 1 oxides, B 2 The oxide and BaTiO3 were ball-milled for 15-20 hours and then calcined in air at 1000-1050℃ for 3-5 hours to obtain the product. And / or, the two types of ceramic solid solutions are prepared by the following method: according to chemical formula A 3 B 3 α B 4 β B 5 γ The stoichiometric ratios of the elements in O3, and B 3 oxides, B 4 The oxide and BaTiO3 were ball-milled for 15-20 hours and then calcined in air at 1050-1100℃ for 3-5 hours to obtain the product.

3. The method for preparing the ceramic material according to claim 1 or 2, characterized in that, The process includes the following steps: mixing a type I ceramic solid solution, a type II ceramic solid solution, MnO2, V2O5 and sintering aids evenly to obtain the ceramic material.

4. A ceramic slurry, comprising ceramic powder, an organic solvent, and a binder, characterized in that, The ceramic powder is the ceramic material described in claim 1 or 2.

5. A multilayer ceramic chip capacitor, characterized in that, This includes ceramic media prepared from the ceramic slurry of claim 4.

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