阅读说明：本技术 一种X8R MLCC用BaTiO3基陶瓷材料的制备方法 (BaTiO for X8R MLCC3Preparation method of base ceramic material ) 是由 郑兴华 张欢 钟诗琪 朱培树 于 2021-09-02 设计创作，主要内容包括：本发明涉及一种X8R MLCC用BaTiO-(3)基准纳米陶瓷材料的制备方法,属于电子信息技术领域。上述制备方法包括以下步骤：1)将BaTiO-(3)粉体与MAS堇青石玻璃粉体混合、球磨、烘干,得到陶瓷粉末；2)在陶瓷粉末中加入粘结剂,造粒、过筛、成型、排胶、烧结,得到陶瓷样品,抛光、镀银后制得X8R MLCC用BaTiO-(3)基陶瓷材料。本发明通过添加MgO-Al-(2)O-(3)-SiO-(2)(MAS)堇青石玻璃成功地改善BaTiO-(3)陶瓷材料的温度稳定性；在-55℃～150℃范围内满足了容温变化率≤±15%；介电常数较高,室温下介电常数大于700；介电损耗较低,室温下介电损耗小于2%；体系不含铅,具有良好的应用前景。(The invention relates to BaTiO for X8R MLCC 3 A preparation method of a reference nano ceramic material belongs to the technical field of electronic information. The preparation method comprises the following steps: 1) mixing BaTiO 3 Mixing the powder with MAS cordierite glass powder, ball-milling and drying to obtain ceramic powder; 2) adding binder into ceramic powder, granulating, sieving, molding, removing binder, sintering to obtain ceramic sample, polishing, and silver-plating to obtain BaTiO 8R for X8R MLCC 3 A base ceramic material. The invention adds MgO-Al 2 O 3 ‑SiO 2 (MAS) cordierite glasses successfully improved BaTiO 3 Temperature stability of the ceramic material; within the range of-55 ℃ to 150 ℃, meets the requirementThe temperature change rate is less than or equal to +/-15 percent; the dielectric constant is higher and is more than 700 at room temperature; the dielectric loss is low and is less than 2% at room temperature; the system does not contain lead and has good application prospect.)

1. BaTiO for X8R MLCC₃The preparation method of the reference nano ceramic material comprises the following steps:

1) mixing BaTiO₃Mixing powder and MAS cordierite glass powder in a proportion of 100: (0.5-2), adding deionized water for ball milling, and drying to obtain ceramic powder;

2) adding a binder into ceramic powder, granulating, sieving, molding, removing binder, sintering, keeping temperature to obtain ceramic sample, polishing, and plating silver to obtain BaTiO 8R MLCC₃A base ceramic material.

2. A method as claimed in claim 1BaTiO for X8R MLCC₃The preparation method of the reference nano ceramic material is characterized by comprising the following steps: the adhesive is PVA or PVB, and the addition amount of the adhesive is 3-5% of the mass of the ceramic powder.

3. The BaTiO 8R MLCC as claimed in claim 1₃The preparation method of the reference nano ceramic material is characterized by comprising the following steps: the ball milling time in the step 1) is 2-12 hours.

4. The BaTiO 8R MLCC as claimed in claim 1₃The preparation method of the reference nano ceramic material is characterized by comprising the following steps: the sintering in the step 2) is 1000-1250 ℃, and the heat preservation time is 2-6 hours.

5. The BaTiO 8R MLCC as claimed in claim 1₃The preparation method of the reference nano ceramic material is characterized by comprising the following steps: the glue discharging temperature in the step 2) is 600 ℃, the heating rate is 2-5 ℃/min, and the heat preservation time is 2-4 hours.

6. The BaTiO 8R MLCC as claimed in claim 1₃The preparation method of the reference nano ceramic material is characterized by comprising the following steps: the BaTiO₃The powder is nano-grade powder.

7. The BaTiO 8R MLCC as claimed in claim 1₃The preparation method of the reference nano ceramic material is characterized by comprising the following steps: the preparation raw materials are all analytically pure raw materials.

Technical Field

The invention belongs to the technical field of electronic informationA BaTiO used for X8R MLCC₃A preparation method of a reference nano ceramic material.

Background

The electronic components are divided into active and passive electronic components, wherein the capacitor accounts for more than 50% of the passive electronic components. Capacitors are widely used in energy storage, filters, bypasses and couplers, and are critical to the proper operation of the circuit. With the progress of capacitor manufacturing technology, the multilayer ceramic capacitor (MLCC) field has made many breakthroughs, which is moving toward miniaturization, high capacity, and high voltage. However, as the electrical characteristics of these high-end MLCC products improve, their high temperature stability is of greater concern. The high-temperature stable MLCC is mainly applied to various vehicle-mounted electronic control devices, national defense and military industry, aerospace and exploration fields, and the working temperature of devices can reach 150 ℃, so that the 125 ℃ working upper limit of the X7R type dielectric material for the traditional MLCC is difficult to meet the application requirements of many fields. And X8R MLCC (in the range of-55 to 150 ℃, Δ C/C) defined by American Electronic Industry Association (EIA)_25°C <15%) has good temperature stability, can meet the strict working temperature requirement of most electronic equipment, and the research thereof is also concerned.

Barium titanate (BaTiO)₃) Has the advantages of high dielectric constant, low sintering temperature and low cost, and is widely used as a host material for ceramic capacitors having high capacity. There are three common methods to improve BaTiO₃The dielectric property temperature stability of (a), makes it suitable for X8R MLCC ceramic materials: (i) t enhancement using effective curie temperature dopants_cValues, e.g. high Curie temperature of PbTiO₃、Na_0.5Bi_0.5TiO₃、Bi₄Ti₃O₁₂(ii) a (ii) Doping Bi-containing oxides can produce stable dielectric properties over a wide temperature range, e.g. Bi (Li)_0.5Nb_0.5 )O₃、Bi(Mg_2/3Ta_1/3 )O₃(ii) a (iii) In BaTiO₃A core-shell structure is formed inside the grains, and the peak dielectric constant of the curie point is suppressed, thereby resulting in stable dielectric properties. Mainly by adding Tm, Yb,Lu, Er, Y and the like form a core-shell structure. The invention patent document with the application number of CN 201510563648.4 discloses a dielectric material for a high-reliability X8R type multilayer ceramic capacitor and a preparation method thereof; the composition of the material comprises Ba_1-xCa_xTiO₃The additive is MnCO₃、MgO、SiO₂、Al₂O₃、ZrO₂、Y₂O₃、Ho₂O₃、Er₂O₃、Yb₂O₃、Gd₂O₃、WO₃、MoO₃、V₂O₅The dielectric material can be used for manufacturing a multilayer ceramic capacitor, the multilayer ceramic capacitor manufactured by the dielectric material meets the X8R characteristic, the average service life under high-temperature load is more than 48h, and the reliability is excellent. The invention patent document with the application number of CN 201810105535.3 discloses a low-temperature sintered temperature-stable X8R type MLCC dielectric material, and the material comprises BaTiO₃、Na_0.5Bi_0.5TiO₃、CaTiO₃、Nb₂O₅、MnCO₃、Co₂O₃And MgO, the material of the invention maintains good dielectric property, lower loss and higher insulation resistivity. The invention patent document with the application number of CN 201811245120.2 discloses a preparation method of a low-loss X8R type dielectric material, and the material component contains BaTiO₃、MnCO₃、MgO、CaZrO₃、SiO₂、Al₂O₃、BaCO₃The material has dielectric constant of 2461 at room temperature, dielectric loss of 0.96%, and insulation resistivity of 3.68 × 10¹¹Ω·cm。

Although the MLCC dielectric materials proposed in many patent documents can satisfy the requirement of X8R, the following disadvantages still exist: 1) the material formula is complex, a plurality of additives are used, and the problem of uniform mixing is easily caused during large-scale production of a plurality of additives. 2) In general, these materials require the addition of certain amounts of rare earth oxides, such as Ho₂O₃、Dy₂O₃. The rare earth oxides are high in price, so that the cost is greatly increased, and the market competition is not facilitated. 3) Some areThe material contains Bi compounds which are volatile at high temperature, even partially react with the metal electrode, and are not beneficial to the subsequent MLCC production. 4) More importantly, the MLCC is now being miniaturized, has high capacity and high pressure, and the single-layer dielectric ceramic has a thickness of 1 μm or less. This requires the dielectric ceramic grain size in MLCCs to be below 200nm to avoid diffusion of the electrodes during co-firing, which leads to device failure. In general, the existing preparation method of the X8R MLCC ceramic material has the problems of complex formula, complex preparation process, lower dielectric constant and larger loss.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides BaTiO for X8R MLCC₃A preparation method of a reference nano ceramic material. The invention adopts nano BaTiO₃Powder (grain size not more than 100nm) as matrix, and adding small amount of MgO-Al₂O₃-SiO₂Preparation of BaTiO by combining (MAS) cordierite glass with rapid sintering and two-step sintering method₃A reference nanoceramic material. The invention adopts simple formula and preparation process to prepare the ceramic material with higher dielectric constant and lower dielectric loss. The ceramic material meets the requirement that the temperature change rate is less than or equal to +/-15% within the range of-55-150 ℃, and has the characteristics of environmental friendliness, low raw material cost and easiness in industrial production.

The technical scheme for solving the problems is as follows:

BaTiO for X8R MLCC₃The preparation method of the base ceramic material comprises the following steps:

1) mixing BaTiO₃Mixing powder and MAS cordierite glass powder in a proportion of 100: (0.5-2), adding deionized water for ball milling, and drying to obtain ceramic powder;

2) adding a binder into ceramic powder, granulating, sieving, molding, removing binder, sintering, keeping temperature to obtain ceramic sample, polishing, and plating silver to obtain BaTiO 8R MLCC₃A base ceramic material.

The invention adopts nano BaTiO₃Powder (grain size not more than 100nm) as matrix, and adding small amount of MgO-Al₂O₃-SiO₂Preparation of BaTiO by combining (MAS) cordierite glass with rapid sintering and two-step sintering method₃A reference nanoceramic material. This is because: 1) reduced BaTiO of cordierite glasses having low softening temperatures₃Ceramic sintering temperature, 2) cordierite glass can show BaTiO₃Transferring medium Ba ions, and 3) shortening the sintering heat preservation time or further reducing the sintering temperature by a rapid sintering and two-step sintering method; these three aspects significantly inhibit BaTiO₃Growth of ceramic grains to obtain BaTiO₃The standard nano ceramic material (the grain diameter is less than 200nm) is suitable for the small-sized and high-capacity MLCC models of 0201, 01005 and the like.

Preferably, in the technical scheme, the binder is PVA or PVB, and the addition amount of the binder is 3-5% of the mass of the ceramic powder.

Preferably, the ball milling time in the step 1) is 2-12 hours.

Preferably, the sintering in the step 2) is 1000-1250 ℃, and the heat preservation time is 2-6 hours.

Preferably, the BaTiO compound is BaTiO₃The powder is nanometer powder (particle size not more than 100 nm).

As the optimization of the technical scheme, the preparation raw materials are all analytically pure raw materials.

In summary, the invention has the following advantages:

(1) the material system of the invention has simple formula, and only MgO-Al is added₂O₃-SiO₂(MAS) cordierite glasses successfully improved BaTiO₃Temperature stability of the ceramic material. The material meets the requirement that the temperature change rate is less than or equal to +/-15% within the range of-55-150 ℃;

(2) the BaTiO for the X8R MLCC₃The dielectric constant of the reference nano ceramic material is higher and is more than 700 at room temperature; the dielectric loss is low and is less than 1.5 percent at room temperature;

(3) BaTiO described in the invention₃The grain diameter of the reference nano ceramic material is less than 200nm, and the ceramic material is suitable for miniaturization and high capacityModel X8R MLCC of 0201, 01005, etc.;

(4) the material system disclosed by the invention does not contain lead, is environment-friendly and has a good application prospect; and the preparation process is simple and controllable, and is convenient for industrial production.

Drawings

FIG. 1 shows BaTiO prepared in examples 1 to 6 and comparative example 1₃XRD pattern of the base ceramic material;

FIG. 2 shows BaTiO prepared in examples 1 and 4 and comparative example₃SEM image of the base ceramic material;

FIG. 3 shows BaTiO prepared in examples 1 to 6₃The change graph of the dielectric constant and the dielectric loss of the base ceramic material at 1kHz along with the temperature;

FIG. 4 shows BaTiO prepared in examples 1 to 6₃A graph of the rate of change of the capacity to temperature (TCC, based on 25 ℃) of the ceramic material at 1kHz as a function of temperature;

FIG. 5 shows BaTiO prepared in comparative example 1₃The change graph of the dielectric constant and the dielectric loss of the base ceramic material at 1kHz along with the temperature;

FIG. 6 shows BaTiO prepared in comparative example 1₃Temperature change rate (TCC, based on 25 ℃) of a ceramic material at 1kHz as a function of temperature.

Detailed Description

In order to make the present invention more comprehensible, the present invention is further described below with reference to examples.

Example 1

BaTiO for X8R MLCC₃The preparation method of the base ceramic material comprises the following specific steps:

(1) mixing BaTiO₃、MgO-Al₂O₃-SiO₂(M AS) cordierite glass according to a mass ratio of 100: 0.5 of ingredients, mixing with deionized water, ball-milling for 4 hours, drying and sieving to obtain ceramic powder.

(2) And (2) adding 5% by mass of PVA binder into the ceramic powder obtained in the step (1), granulating, and molding to obtain a ceramic blank with the diameter of 10mm to 1 mm. The ceramic blank is kept at 600 ℃ for 2 hours for binder removal, then is heated to 1100 ℃ for sintering, is kept at the temperature for 3 hours, and is polished and plated with silver to obtain the ceramic materialTo BaTiO₃A reference nanoceramic material.

Example 2

BaTiO for X8R MLCC₃The preparation method of the base ceramic material comprises the following specific steps:

(1) mixing BaTiO₃、MgO-Al₂O₃-SiO₂(M AS) cordierite glass according to a mass ratio of 100: 1, mixing the materials with deionized water, ball-milling the mixture for 4 hours, drying and sieving the mixture to obtain ceramic powder.

(2) And (2) adding 5% by mass of PVA binder into the ceramic powder obtained in the step (1), granulating, and molding to obtain a ceramic blank with the diameter of 10mm to 1 mm. The ceramic blank is insulated for 2 hours at 600 ℃ for binder removal, then is heated to 1150 ℃ for sintering, is insulated for 3 hours, and is polished and silvered to obtain BaTiO₃A reference nanoceramic material.

Example 3

BaTiO for X8R MLCC₃The preparation method of the base ceramic material comprises the following specific steps:

(1) mixing BaTiO₃、MgO-Al₂O₃-SiO₂(M AS) cordierite glass according to a mass ratio of 100: 0.5 of ingredients, mixing with deionized water, ball-milling for 4 hours, drying and sieving to obtain ceramic powder.

(2) And (2) adding 5% by mass of PVA binder into the ceramic powder obtained in the step (1), granulating, and molding to obtain a ceramic blank with the diameter of 10mm and the thickness of 1m m. The ceramic blank is kept at 600 ℃ for 2 hours for glue discharging, then is heated to 1200 ℃ and kept for 30min, and then is rapidly cooled, polished and plated with silver to obtain BaTiO₃A reference nanoceramic material.

Example 4

BaTiO for X8R MLCC₃The preparation method of the base ceramic material comprises the following specific steps:

(1) mixing BaTiO₃、MgO-Al₂O₃-SiO₂(M AS) cordierite glass according to a mass ratio of 100: 0.5 of ingredients, mixing with deionized water, ball-milling for 4 hours, drying and sieving to obtain ceramic powder.

(2) Adding 5 mass percent of PVA (polyvinyl alcohol) binder into the ceramic powder obtained in the step (1), and granulatingAnd forming to obtain a ceramic blank with the diameter of 10mm and the thickness of 1m m. The ceramic blank is kept at 600 ℃ for 2 hours for binder removal, then is heated to 1250 ℃ for 30 minutes, is quickly cooled, polished and plated with silver to obtain BaTiO₃A reference nanoceramic material.

Example 5

BaTiO for X8R MLCC₃The preparation method of the base ceramic material comprises the following specific steps:

(1) mixing BaTiO₃、MgO-Al₂O₃-SiO₂(M AS) cordierite glass according to a mass ratio of 100: 0.5 of ingredients, mixing with deionized water, ball-milling for 4 hours, drying and sieving to obtain ceramic powder.

(2) And (2) adding 5% by mass of PVA binder into the ceramic powder obtained in the step (1), granulating, and molding to obtain a ceramic blank with the diameter of 10mm and the thickness of 1m m. The ceramic blank is kept at 600 ℃ for 2 hours for binder removal, then is heated to 1200 ℃ for 10 minutes, is quickly cooled to 1000 ℃ for 6 hours, and is polished and silvered to obtain BaTiO₃A reference nanoceramic material.

Example 6

BaTiO for X8R MLCC₃The preparation method of the base ceramic material comprises the following specific steps:

(1) mixing BaTiO₃、MgO-Al₂O₃-SiO₂(M AS) cordierite glass according to a mass ratio of 100: 1, mixing the materials with deionized water, ball-milling the mixture for 4 hours, drying and sieving the mixture to obtain ceramic powder.

(2) And (2) adding 5% by mass of PVA binder into the ceramic powder obtained in the step (1), granulating, and molding to obtain a ceramic blank with the diameter of 10mm and the thickness of 1m m. The ceramic blank is kept at 600 ℃ for 2 hours for binder removal, then is heated to 1200 ℃ for 10 minutes, is quickly cooled to 1000 ℃ for 6 hours, and is polished and silvered to obtain BaTiO₃A reference nanoceramic material.

Comparative example 1

BaTiO₃The preparation method of the ceramic material comprises the following specific steps:

mixing pure BaTiO₃Adding 5% PVA binder to the powder, granulating, molding, and making into final productObtaining a ceramic blank with the diameter of 10mm to 1m m. The ceramic blank is kept at 600 ℃ for 2 hours for binder removal, then is heated to 1225 ℃ for 2 hours, and is polished and silvered to obtain BaTiO₃A ceramic material.

BaTiO prepared in examples 1-6 and comparative example₃The base ceramic material is subjected to XRD test, the XRD pattern is shown in figure 1, and the analysis shows that: all ceramic samples were a single perovskite phase.

BaTiO prepared in example 1₃The average grain size of the base ceramic material is 148 nm; BaTiO prepared in example 2₃The average grain size of the base ceramic material is 136 nm; BaTiO prepared in example 3₃The average grain size of the base ceramic material is 144 nm; BaTiO prepared in example 4₃The average grain size of the base ceramic material is 148 nm; EXAMPLE 5 preparation of BaTiO₃The average grain size of the base ceramic material is 150 nm; BaTiO prepared in example 6₃The average grain size of the base ceramic material is 136 nm. BaTiO prepared in comparative example 1₃The ceramic material has an average grain size of 2560 nm. In which BaTiO prepared in example 1, example 4 and comparative example 1₃The base ceramic material is subjected to SEM scanning, and SEM images are respectively shown in (a), (b) and (c) of FIG. 2. It can be seen that BaTiO obtained in the examples₃The grain size of the ceramic material is far smaller than that of the comparative example, the grain size of the ceramic material does not exceed 150nm, and the fact that the quasi-nano BaTiO is obtained is shown₃A base ceramic material.

BaTiO to be prepared₃Dielectric property test was performed after polishing a sample of the base ceramic material to prepare a silver electrode, and the change of dielectric constant and dielectric loss with temperature and the rate of change of capacity temperature (TCC, based on 25 ℃) at 1kHz were shown in fig. 3 to 6. As can be seen from the figure, comparative example 1 has a sharp dielectric peak at around 125 ℃, so the temperature stability of the dielectric constant is poor, and the temperature stability requirements of X7R and X8R cannot be met; the corresponding dielectric peak of the embodiments 1-6 is obviously reduced, so that the change of the dielectric constant is small in the temperature range of-55 ℃ to 150 ℃, wherein, the graph of FIG. 4 shows that the dielectric performance and the temperature tolerance characteristics of the embodiments 2-6 meet the requirement of an X8R capacitor (namely, the temperature change rate is not more than +/-15% in the temperature range of-55 ℃ to 150 ℃, and is shown by a dashed line frame), and the dielectric performance and the temperature tolerance characteristics are between-55 ℃ and 1Low dielectric loss (less than 2.0 percent) in the temperature range of 50 ℃;

in which Table 1 shows the preparation of BaTiO for examples 1-6 and comparative example 1₃Dielectric properties of the base ceramic samples were compared:

the dielectric constant and dielectric loss at 25 ℃ at 1kHz were 832 and 0.65% (example 1), 801 and 0.76% (example 2), 806 and 0.80% (example 3), 1385 and 1.51% (example 4), 998 and 0.65% (example 5), 755 and 1.04% (example 6), 3307 and 3.14% (comparative example 1), respectively. As can be seen from Table 1, BaTiO compounds prepared in examples 1 to 6₃Base ceramic material compared to BaTiO prepared in comparative example 1₃The ceramic material has the advantages of reduced dielectric constant and dielectric loss, obviously improved temperature stability of dielectric property and good temperature stability within the temperature range of-55-150 ℃, wherein BaTiO prepared in the examples 2-6₃The base ceramic material satisfies X8R (Δ C/C within-55-150 ℃)_25°C <± 15%) standard requirements. Meanwhile, BaTiO obtained in example₃The grain size of the ceramic material is not more than 150nm, which shows that the quasi-nano BaTiO is obtained₃The ceramic material is suitable for X8R type MLCCs such as 0201, 01005, etc. with small size and high capacity.