Wide-temperature-range stable multilayer composite ceramic material as well as preparation method and application thereof

Abstract

The invention discloses a stable multi-layer composite ceramic material with a wide temperature range and a preparation method and application of the stable multi-layer composite ceramic material. The multilayer composite ceramic material is obtained by stacking and processing a BaTiO3 layer, a Ba (ZrxTi1-x) O3 layer, a (Ba0. 95Ca0. 05) (Ti1-ySny) O3 layer and a Ba (Ti1-zSnz) O3 layer, during preparation, a Joule thermal sintering technology is adopted, the temperature is increased to 1300-1450 DEG C at the rate of 1000 DEG C / min in an argon atmosphere and is temporarily kept for 1-3 minutes, interlayer element diffusion is greatly inhibited, and a structure in which multiple ceramic phases coexist is successfully constructed. The multilayer ceramic capacitor prepared by using the method shows stable and high dielectric constant and low loss, meets X7R characteristic requirements, solves the technical problem that wide-temperature-range performance stability is difficult to realize due to the fact that a solid solution is formed due to long-time diffusion in traditional sintering, and is suitable for being applied to electronic devices in relatively complex environments.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, specifically relating to a wide-temperature-range stable multilayer composite ceramic material, its preparation method, and its application. Background Technology

[0002] In recent years, with the development of intelligent manufacturing and the automotive industry, multilayer ceramic capacitors have gradually come into the public eye. These miniaturized, high-performance, and highly reliable electronic components are used in various industries. However, the stable application of multilayer ceramic capacitors in the different environments of these industries has become a new challenge. In the automotive industry, the starting temperature is low in winter and extremely high during driving in summer. Therefore, a multilayer ceramic capacitor that can operate stably under both high and low temperatures has become a current research frontier and hot topic.

[0003] Patent CN117361611A discloses a method for preparing a core-shell ceramic capacitor, which stabilizes the dielectric constant by introducing a core-shell structure. The inventors construct the core-shell structure in ceramic using shell and core layer additives, and simultaneously prepare smaller barium titanate ceramic powders using a hydrothermal method. However, some problems exist: while the core-shell structure provides dielectric stability, defects such as vacancies and impurities are prone to appear at the core-shell interface, resulting in a dielectric constant and breakdown voltage far lower than that of a pure barium titanate matrix. Furthermore, the hydrothermal synthesis process is complex.

[0004] Patent CN116969503A discloses a method for preparing nanoscale barium titanate via hydrothermal reaction, thereby producing barium titanate nanopowder that can be directly applied to multilayer ceramic capacitors. However, while the hydrothermal reaction method used in the above invention can effectively control particle size, it requires a longer reaction time, resulting in lower production efficiency. Furthermore, the hydrothermal reaction equipment requires high-pressure reactors and other equipment, increasing production costs in industrial applications.

[0005] Zhihao Dong et al. prepared multilayer ceramic structures using composite material lamination, thereby combining the common characteristics of various ceramics and constructing a relatively stable dielectric temperature spectrum. However, due to the limitation of the heating rate, diffusion still exists during firing, resulting in solid solutions of various components in the dielectric temperature spectrum and a certain deviation in the Curie temperature.

[0006] Ceramics possess high thermal, mechanical, and chemical stability, making them widely used in electronics, energy storage, and extreme environments. Traditional ceramic sintering typically requires several hours of processing time, which can hinder the development of advanced ceramic materials. Furthermore, due to diffusion and volatilization inherent in the ceramic matrix during prolonged sintering, the extended sintering process inevitably impacts the ceramic matrix. Therefore, to meet the needs of modern emerging ceramics, a Joule heating device sintering method for ceramic synthesis has been introduced. This method offers uniform temperature distribution and a rapid heating rate (-10°C). 3 ~10 4 ℃ / min), fast cooling rate (10 4 It features high sintering temperature (up to 3000℃ / min) and high sintering temperature (up to 3000℃). Summary of the Invention

[0007] This invention addresses the shortcomings of the prior art by providing a wide-temperature-range stable multilayer composite ceramic material, its preparation method, and its applications. The ceramic material provided by this invention exhibits a relatively stable dielectric constant and can maintain stability over a wide temperature range.

[0008] The multilayer composite ceramic material of the present invention consists of a BaTiO3 layer and a Ba(Zr) layer. x Ti 1-x )O3 layer, (Ba 0.95 Ca 0.05 (Ti) 1-y Sn y O3 layer and Ba(Ti) 1-z Sn z O3 was obtained by layering and processing. x, y, and z are the atomic percentages of each element in the corresponding layer composition: 0 < x < 1, 0 < y < 1, 0 < z < 1.

[0009] The composition of each layer by mass fraction is as follows:

[0010] BaTiO3 45~50 parts, Ba(Zr) x Ti 1-x )O310~20 portions, (Ba 0.95 Ca 0.05 (Ti) 1-y Sn y )O310~20 parts and Ba(Ti 1-z Sn z )O3 15~25 servings.

[0011] The preparation method of the multilayer composite ceramic material of the present invention includes the following steps:

[0012] Step 1: Using BaCO3, TiO2, ZrO2, CaCO3 and SnO2 as raw materials, the above raw materials are mixed according to the element ratio required for each layer of the ceramic matrix. After mixing the raw materials required for each layer, anhydrous ethanol is added and ball milled. After drying the slurry, the corresponding powders for each layer are obtained.

[0013] Step 2: The corresponding powders of each layer are pre-fired for the first time and the second time in sequence. The resulting products are ball-milled and dried to obtain the corresponding clinker of each layer.

[0014] Furthermore, the conditions for the first pre-firing are: heating at a rate of 3-5℃ / min and holding for 2-3 hours; the conditions for the second pre-firing are: heating at a rate of 3-5℃ / min and holding for 2-3 hours.

[0015] Furthermore, the holding temperature for the two pre-firing of the BaTiO3 layer is 1150~1200℃; Ba(Zr x Ti 1-x The heat preservation temperature for the two pre-firing of the O3 layer is 1100~1200℃; (Ba 0.95 Ca 0.05 (Ti) 1-y Sn y The O3 layer is pre-fired twice at a temperature of 1100~1200℃; Ba(Ti 1-z Sn z The heat preservation temperature for the two pre-firing of the O3 layer is 1100~1200℃.

[0016] Step 3: Add polyvinyl butyral to the corresponding clinker obtained in Step 2 and mix, then add anhydrous ethanol and ball mill. After drying the resulting slurry, the corresponding pre-calcined material for each layer is obtained.

[0017] Step 4: According to BaTiO3, Ba(Zr) x Ti 1-x O3、(Ba 0.95 Ca 0.05 (Ti) 1-y Sn y O3, Ba(Ti) 1-z Sn z In the order of O3, the corresponding pre-fired materials are laminated and stacked in sequence, and then cold-pressed using a mold to obtain a ceramic green body;

[0018] Step 5: Use a Joule heating device to sinter the obtained ceramic green body. After sintering, anneal the sample to obtain a multilayer composite ceramic material.

[0019] Furthermore, in steps 1 and 3, the ball milling conditions are as follows: the mass ratio of the mixture to the zirconia milling balls is 1:3-5; the mass ratio of the mixture to anhydrous ethanol is 0.8-1:1; and the ball milling is carried out at a speed of 200-300 r / min for 8-12 h. The drying conditions are as follows: drying at 90-100℃ for 10-12 h.

[0020] Furthermore, in step 4, the specific operation of laminating and stacking the corresponding pre-fired materials is as follows: each layer of pre-fired material is placed sequentially in the mold, each layer is flattened before the next layer is placed on top, and so on, until pressure is applied to the mold to ensure the complete bonding of the four powders. The order of the four powders should be arranged according to the Curie temperature difference between ceramics, with similar Curie temperatures grouped together.

[0021] Furthermore, in step 4, the cold pressing process uses a pressure of 2-5 MPa and a holding pressure of 10-30 seconds.

[0022] Furthermore, in step 5, the ceramic green body needs to be debinded before Joule sintering. Specifically, the ceramic green body is heated to 600℃ in a box furnace at a rate of 2-3℃ / min and held for 1 hour.

[0023] Furthermore, in step 5, the Joule heating sintering parameters are as follows: in an argon atmosphere, the sintering temperature is 1300~1450℃, the heating rate is 1000℃ / min, and the sintering time is 1~3min.

[0024] Furthermore, in step 5, the annealing conditions are: in an air atmosphere, the temperature is increased to 600°C at a rate of 5°C / min and held for 3 hours.

[0025] This invention relates to the application of multilayer composite ceramic materials as dielectric materials in capacitor manufacturing.

[0026] Specifically, the multilayer composite ceramic material is silvered and then used as a dielectric material to prepare ceramic capacitors.

[0027] The silvering process involves applying silver electrodes to both ends of a ceramic sample that has undergone simple polishing. The specific steps for silvering are as follows: the surface of the ceramic sheet is polished smooth, silver paste is applied, and the sample is heated to 550°C in an electric furnace at a rate of 5°C / min, with a holding time of 30min.

[0028] The beneficial effects of this invention are reflected in:

[0029] The preparation method of this invention is simple to operate. Unlike other powder preparation methods, this invention adopts a solid-state sintering method, reducing the complexity of ceramic preparation schemes, and uses a Joule heating device for sintering. In the traditional sintering process, due to the slow heating rate (usually less than 10-20℃ / min) and the need for high-temperature and long-term holding, material diffusion and solid solution of different components inevitably occur inside the ceramic. Therefore, the traditional sintering usually results in a solid solution. At the same time, due to the difference in sintering temperatures of the four materials, samples sintered by traditional solid-state sintering are prone to warping and deformation. In contrast, Joule thermal sintering can carry out the sintering reaction much faster, completing the sintering process in a very short time (only a few seconds to tens of seconds). Due to the extremely short time, the diffusion inside the various ceramics is almost negligible, thus obtaining a composite material with multiple ceramic structures coexisting.

[0030] The dielectric temperature spectrum of the multilayer composite ceramic material of this invention has a temperature variation of no more than ±15%, which meets the requirements of X7R ceramic materials. It has a high dielectric constant (around 2500-3000 at room temperature) and the multilayer composite ceramic capacitor prepared therefrom has a low dielectric loss (0.01-0.05 at room temperature). Attached Figure Description

[0031] Figure 1 The dielectric temperature spectra of the sintered ceramics of each component in Examples 1-4 are shown.

[0032] Figure 2 The dielectric temperature spectrum of each component of the multilayer ceramic capacitor in Examples 5-7 is shown in the diagram.

[0033] Figure 3 This is a schematic diagram showing the temperature changes of each component of the multilayer ceramic capacitor in Examples 5-7 over a wide temperature range.

[0034] Figure 4 This is a schematic diagram comparing the dielectric temperature spectra of the multilayer ceramic capacitors of each component in Examples 5, 8-10.

[0035] Figure 5 This is a schematic diagram comparing the temperature changes of each component in the multilayer ceramic capacitors of Examples 5-10 over a wide temperature range.

[0036] Figure 6 The images are XRD patterns at room temperature for Examples 1-4.

[0037] Figure 7 The images shown are XRD patterns at room temperature for Examples 5-7.

[0038] Figure 8 This is the SEM image of Example 5. Detailed Implementation

[0039] The technical solution of the present invention will be further analyzed and described below through specific embodiments to facilitate understanding of the present invention by those skilled in the art. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they fall within the spirit and scope of the present invention as defined and determined by the appended claims, and all inventions utilizing the concept of the present invention are within the scope of protection.

[0040] The multilayer composite ceramic material of the present invention consists of a BaTiO3 layer and a Ba(Zr) layer. x Ti 1-x )O3 layer, (Ba 0.95 Ca 0.05 (Ti) 1-y Sn y O3 layer and Ba(Ti) 1-z Sn z O3 was obtained by layering and processing. x, y, and z are the atomic percentages of each element in the corresponding layer composition: 0 < x < 1, 0 < y < 1, 0 < z < 1.

[0041] To ensure the stability of the dielectric constant of ceramic materials, BaTiO3 initially determines the overall performance of multilayer ceramic capacitors in the high-temperature region (100~130℃); Ba(Zr x Ti 1-x O3 initially determines the overall performance of multilayer ceramic capacitors in the medium temperature range (60~100℃); Ba 0.95 Ca 0.05 (Ti) 1-y Sn y O3 initially determines the overall performance of multilayer ceramic capacitors in the room temperature region 1 (0~60℃); Ba(Ti) 1-z Sn z O3 initially determines the overall performance of the multilayer ceramic capacitor in the room temperature region 2 (-50~0℃). Different values ​​of x, y, and z only affect the specific Curie temperature and can be adjusted as needed. In the example of this invention, the values ​​of x, y, and z are 0.09, 0.132, and 0.2, respectively.

[0042] The preparation method of the multilayer composite ceramic material of the present invention includes the following steps:

[0043] Step 1: Using BaCO3, TiO2, ZrO2, CaCO3 and SnO2 as raw materials, the raw materials are mixed according to the element ratio required for each layer of the ceramic matrix. After mixing the raw materials required for each layer, anhydrous ethanol is added for ball milling. The mass ratio of the mixture to the zirconia milling balls is 1:3-5, and the mass ratio of the mixture to anhydrous ethanol is 0.8-1:1. The mixture is ball-milled for 12 hours at 300 r / min using a QM-3SP4 planetary ball mill from Nanjing Nanda Instrument Co., Ltd. The resulting slurry is dried at 90-100℃ for 10-12 hours to obtain the corresponding powders for each layer.

[0044] In this invention, the raw materials BaCO3, TiO2, ZrO2, CaCO3 and SnO2 are preferably of analytical grade.

[0045] Step 2: The corresponding powders of each layer are subjected to a first pre-calcination and a second pre-calcination in sequence. The resulting products are ball-milled and dried to obtain the corresponding clinker of each layer. The preferred calcination temperature for the corresponding powders of each layer is 1200℃, the preferred calcination time is 4 hours, and the preferred number of calcinations is two, to obtain the corresponding clinker of each layer.

[0046] Step 3: Add 0.7 wt% polyvinyl butyral (PVB) to each layer of clinker obtained in Step 2 and mix. Then add anhydrous ethanol and ball mill. After drying the resulting slurry, obtain the corresponding pre-calcined material for each layer. The ball milling and drying methods are the same as the method for obtaining powder from the slurry.

[0047] Step 4: Arrange according to Curie temperature from high to low (BaTiO3, Ba(Zr) x Ti 1-x O3、(Ba 0.95 Ca 0.05 (Ti) 1-y Sn y O3, Ba(Ti) 1-z Sn z Following the order of O3), the corresponding pre-burned materials are stacked in sequence. Each layer is flattened before the next layer is added. Finally, after four layers are stacked, they are pressed once. The pressure conditions are preferably 2~4MPa, thus obtaining a raw sheet with a thickness of about 1mm. At the same time, it is necessary to ensure that there are no cracks or gaps on the surface of the pressed sheet.

[0048] Step 5: Sinter the obtained ceramic green body using a Joule heating device. Place the ceramic green body on the Joule heating device and sinter it at 1300°C~1450°C, wherein the preferred heating rate is 1000°C / min and the preferred sintering time is 1~2 min. Since the Joule heating device is in an argon atmosphere, oxygen is lacking during the sintering process, resulting in oxygen vacancies in the ceramic matrix. Therefore, the ceramic matrix should be annealed and oxidized in air after sintering. The preferred annealing and oxidation temperature is 600°C and the preferred time is 3 hours.

[0049] After completing the above operations, the fabrication of the multilayer ceramic capacitor can proceed according to the following steps:

[0050] First, silver coating is performed: silver paste is used as the electrode material. Before applying the silver paste, surface treatment should be carried out, preferably by sanding the surface with sandpaper to ensure that the upper and lower surfaces are smooth and flat. However, due to the special composition of this ceramic, sanding should not be excessive to avoid damaging its ceramic component ratio. After cleaning, drying is performed. After these operations are completed, subsequent silver coating can be performed. After silver coating, sintering is carried out. The preferred sintering time is 0.5 hours, and the preferred calcination temperature is 550℃.

[0051] This invention utilizes the different phenomena observed in different ceramics at different temperatures to produce a novel combined effect, offering a new approach to the coexistence of multiple ceramic materials. The dielectric constant and dielectric loss of the dielectric material in this invention were tested at 1 kHz, and the multilayer ceramic capacitor exhibits X7R characteristics, demonstrating high dielectric constant and low dielectric loss.

[0052] Example 1:

[0053] BaCO3 and TiO2 were mixed in a molar ratio of 1:1 and then ball-milled and pre-calcined. The preferred calcination temperature was 1200℃ and the preferred holding time was 4h. The pre-calcination was carried out twice. After pre-calcination, the powder was mixed with 0.7% PVB by weight and ball-milled to obtain the BaTiO3 layer pre-calcined material.

[0054] Example 2:

[0055] Preparation of Ba(Zr) x Ti 1-x The O3 layer pre-burned material was prepared in the same way as in Example 1, except that the component ratio was as shown in Example 2 in Table 1.

[0056] Example 3:

[0057] Preparation of (Ba 0.95 Ca 0.05 (Ti) 1-y Sn yThe O3 layer pre-burned material was prepared in the same way as in Example 1, except that the component ratio was as shown in Example 3 in Table 1.

[0058] Example 4:

[0059] Preparation of Ba(Ti) 1-z Sn z The O3 layer pre-burned material was prepared in the same way as in Example 1, except that the component ratio was as shown in Example 4 in Table 1.

[0060] Example 5:

[0061] To prepare a multilayer ceramic capacitor, the pre-sintered materials obtained in Examples 1, 2, 3, and 4 were laminated according to the proportions in Example 5 of Table 2, with the preferred lamination order being Examples 1, 2, 3, and 4. After the four layers were stacked, they were pressed into a preform. The preferred heating rate was 3℃ / min, the temperature was 600℃ for debinding, and the preferred holding time was 1 hour. After debinding, the ceramic preform was sintered using a Joule heating device, with the preferred sintering heating rate being 1000℃ / min, the sintering temperature being 1400℃, and the holding time at 1400℃ being 30 seconds. After sintering, it was annealed at 600℃ for 3 hours, and finally silver-coated to form the multilayer ceramic capacitor.

[0062] Example 6:

[0063] Multilayer ceramic capacitors were prepared using the same method as in Example 5, except that the component ratios were as shown in Example 6 in Table 2.

[0064] Example 7:

[0065] Multilayer ceramic capacitors were prepared using the same method as in Example 5, except that the component ratios were as shown in Example 7 in Table 2.

[0066] Example 8:

[0067] Multilayer ceramic capacitors were prepared using the same method as in Example 5, except that the lamination sequence was as shown in Example 8 in Table 3.

[0068] Example 9:

[0069] Multilayer ceramic capacitors were prepared using the same method as in Example 5, except that the lamination sequence was as shown in Example 9 in Table 3.

[0070] Example 10:

[0071] Multilayer ceramic capacitors were prepared using the same method as in Example 5, except that the lamination sequence was as shown in Example 10 in Table 3.

[0072] Table 1 shows the weight percentage of each component required for the raw material ceramic powder used in the preparation of multilayer ceramic capacitors in Examples 1-4.

[0073] Table 2 shows the proportions of each ceramic powder component in the preparation of multilayer ceramic capacitors in Examples 5-7.

[0074] Table 3 shows the stacking order of ceramic powders in the preparation of multilayer ceramic capacitors in Examples 5, 8-10.

[0075]

[0076]

[0077]

[0078] from Figure 1 It can be seen that the three experimental groups all exhibit similar structures, with certain peaks at 40℃, 90℃, and 120℃, compared to... Figure 1 Examples 1-4 show four Curie temperature peaks, meaning that the structures of Examples 1-4 are present in Examples 5-7. Lamination Joule heating sintering can effectively suppress diffusion. The sintered multilayer ceramic capacitor is a composite material with all four structures present. By modifying the proportions of Examples 1-4 in Examples 5-7, a relatively stable multilayer ceramic capacitor can be obtained.

[0079] exist Figure 3 It can be observed that Examples 5-7 all satisfy X7S, and by improving the ratio, a multilayer ceramic capacitor that satisfies X7R can be obtained, namely Example 5.

[0080] Figure 5 The results show the effect of different lamination sequences on the temperature stability of multilayer ceramics. Examples 8 and 9 meet the X7S standard, while example 9 is close to the X7R standard.

[0081] Figure 7 Examples 5-7 show that due to insufficient sintering time during Joule heating, grain growth is incomplete, resulting in lower characteristic peak values, but the traditional perovskite structure is still maintained. At the same time, due to the inhibition of diffusion, a more complex peak structure is maintained at 45°.

[0082] Figure 8 It is evident that Example 5 exhibits a multilayer composite structure after Joule heating sintering.

Claims

1. A multilayer composite ceramic material with wide temperature range stability, characterized in that: The multilayer composite ceramic material consists of a BaTiO3 layer and a Ba(Zr) layer. x Ti 1-x )O3 layer, (Ba 0.95 Ca 0.05 (Ti) 1-y Sn y O3 layer and Ba(Ti) 1-z Sn z O3 layers are obtained by further processing after stacking; 0 < x < 1, 0 < y < 1, 0 < z < 1.

2. The wide-temperature-range stable multilayer composite ceramic material according to claim 1, characterized in that: The composition of each layer by mass parts is: 45-50 parts BaTiO3, 45-50 parts Ba(Zr) x Ti 1-x )O310~20 portions, (Ba 0.95 Ca 0.05 (Ti) 1- y Sn y )O310~20 parts, Ba(Ti 1-z Sn z )O3 15~25 servings.

3. The method for preparing the wide-temperature-range stable multilayer composite ceramic material according to claim 1 or 2, characterized in that... Includes the following steps: Step 1: Using BaCO3, TiO2, ZrO2, CaCO3 and SnO2 as raw materials, the above raw materials are mixed according to the element ratio required for each layer of the ceramic matrix. After mixing the raw materials required for each layer, anhydrous ethanol is added and ball milled. After drying the slurry, the corresponding powders for each layer are obtained. Step 2: The corresponding powders of each layer are subjected to a first pre-firing and a second pre-firing in sequence. The resulting products are ball-milled and dried to obtain the corresponding clinker of each layer. Step 3: Add polyvinyl butyral to the corresponding clinker obtained in Step 2 and mix, then add anhydrous ethanol and ball mill. After drying the resulting slurry, the corresponding pre-calcined material for each layer is obtained. Step 4: According to BaTiO3, Ba(Zr) x Ti 1-x O3、(Ba 0.95 Ca 0.05 (Ti) 1-y Sn y O3, Ba(Ti) 1-z Sn z In the order of O3, the corresponding pre-fired materials are laminated and stacked in sequence, and then cold-pressed using a mold to obtain a ceramic green body; Step 5: Use a Joule heating device to sinter the obtained ceramic green body. After sintering, anneal the sample to obtain a multilayer composite ceramic material.

4. The preparation method according to claim 3, characterized in that: In step 2, the conditions for the first pre-firing are: heating at a rate of 3-5℃ / min and holding for 2-3 hours; the conditions for the second pre-firing are: heating at a rate of 3-5℃ / min and holding for 2-3 hours.

5. The preparation method according to claim 4, characterized in that: The holding temperature for the two pre-firings of the BaTiO3 layer is 1150~1200℃; Ba(Zr x Ti 1-x The heat preservation temperature for the two pre-firing of the O3 layer is 1100~1200℃; (Ba 0.95 Ca 0.05 (Ti) 1-y Sn y The O3 layer is pre-fired twice at a temperature of 1100~1200℃; Ba(Ti 1- z Sn z The heat preservation temperature for the two pre-firing of the O3 layer is 1100~1200℃.

6. The preparation method according to claim 4, characterized in that: In step 4, the specific operation of laminating and stacking the corresponding pre-fired materials is as follows: each corresponding pre-fired material is placed in the mold in sequence, each layer of pre-fired material is flattened and then another layer of pre-fired material is placed, and so on, until finally pressure is applied to the mold to ensure that the four powders are completely bonded together.

7. The preparation method according to claim 4, characterized in that: In step 4, cold pressing is performed at a pressure of 2-5 MPa for 10-30 seconds.

8. The preparation method according to claim 4, characterized in that: In step 5, the Joule heating sintering parameters are as follows: in an argon atmosphere, the sintering temperature is 1300~1450°C, the heating rate is 1000°C / min, and the sintering time is 1~3min.

9. The preparation method according to claim 4, characterized in that: In step 5, the annealing conditions are: in an air atmosphere, the temperature is increased to 600°C at a rate of 5°C / min and held for 3 hours.

10. The application of the wide-temperature-range stable multilayer composite ceramic material as a dielectric material in capacitor fabrication, as described in claim 1 or 2.

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