Titanate-based ceramic as well as preparation method and application for inhibiting high-temperature electric leakage of titanate-based ceramic

Abstract

The invention discloses titanate-based ceramic as well as a preparation method and application for inhibiting high-temperature electric leakage of the titanate-based ceramic. The preparation method comprises the following steps: weighing raw materials according to a structural general formula (1-x) ATiO3-xM; wherein A comprises at least one of elements Ba, Sr, Ca and Mg, M comprises at least one of MgO, ZnO, Li2O, Na2O, K2O and Y2O3, and x ranges from 0.04 wt% to 30 wt%; mixing the weighed raw materials, preparing a sample, and sintering by adopting a solid phase method; placing the sintered sample between graphite felts, placing the graphite felts in a closed air pressure box, and vacuumizing until the air pressure needs to be lower than-0.095 MPa; applying current to the sample to generate Joule heat, rapidly raising the temperature to 900-1500 DEG C at the temperature raising rate of 30-80 DEG C / min, keeping the temperature for 30-180 seconds, turning off a power supply, and removing vacuum after the sample is cooled; the ceramic wafer is subjected to vacuum ultrafast heating again on the basis of traditional sintering, the dielectric property of the original ceramic wafer is further improved through short-time vacuum high temperature, high-temperature electric leakage of the ceramic wafer is reduced, operation is easy, production efficiency is high, cost is saved, and green production is achieved.

Description

Technical Field

[0001] This invention belongs to the field of ceramic capacitor technology, and relates to a method for preparing titanate-based ceramics, specifically to a titanate-based ceramic and its preparation method and application for suppressing high-temperature leakage. Background Technology

[0002] Titanate-based ceramics (such as BaTiO3, SrTiO3, CaTiO3, and their solid solutions) have become core materials in fields such as electronics, new energy, and aerospace due to their excellent dielectric properties, thermal stability, and mechanical strength. They are widely used in key components such as high-temperature ceramic capacitors, power device packaging, and sensors. These ceramic components need to operate stably in high-temperature environments above 100°C for extended periods, and their leakage characteristics directly determine the operational accuracy, reliability, and safety of the equipment. However, traditional titanate-based ceramics generally face serious leakage problems at high temperatures: on the one hand, high temperatures exacerbate defect migration within the ceramic lattice (such as the diffusion of oxygen vacancies and ion vacancies), forming leakage channels; on the other hand, traditional solid-state sintering processes easily lead to uneven grain size and grain boundary impurity segregation, further reducing insulation performance at high temperatures, manifested as increased leakage current and soaring dielectric loss. This problem not only leads to increased energy loss and decreased operating efficiency of components but may also cause thermal breakdown, short circuits, and other faults, severely limiting the application expansion of titanate-based ceramics in critical high-temperature fields. To address the problem of high-temperature leakage, existing technologies mainly include optimizing the sintering process, which can reduce defects to some extent, but it can easily lead to excessive grain growth, thereby increasing the risk of grain boundary leakage. In addition, it has high energy consumption and long production cycle. Doping modification processes are complex and have poor compatibility. Excessive doping may damage the original dielectric properties of ceramics. Surface coating can improve surface insulation, but it cannot solve the bulk leakage caused by internal defects in ceramics. Furthermore, the coating has insufficient bonding stability with the substrate and is prone to detachment and failure at high temperatures. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing titanate-based ceramics and suppressing high-temperature leakage. Based on traditional sintering, the ceramic sheet is subjected to vacuum ultrafast heating again. This short-term vacuum high temperature further improves the dielectric properties of the original ceramic sheet, reducing high-temperature leakage. The method is simple to operate and cost-effective.

[0004] To achieve the above objectives, the present invention employs the following technical solution: A method for preparing titanate-based ceramics includes the following steps: Step 1: Weigh the raw materials according to the general structural formula (1-x)ATiO3-xM; wherein, A includes at least one of the elements Ba, Sr, Ca, and Mg, M includes at least one of MgO, ZnO, Li2O, Na2O, K2O, and Y2O3, and x takes a value of 0.04wt%-30wt%; Step 2: After mixing the raw materials weighed in Step 1 to prepare a sample, sinter it using a solid-state method. Step 3: Place the sintered sample between graphite felts and place it in a sealed pressure chamber to evacuate until the pressure is below -0.095 MPa; Step 4: Apply an electric current to the sample to generate Joule heating, rapidly heating it to 900-1500℃ at a heating rate of 30-80℃ / min. Hold the temperature for 30-180 seconds, then turn off the power. After the sample cools down, remove the vacuum.

[0005] The present invention also has the following technical features: Preferably, in step one, x takes the value of 0.04wt%-10wt%.

[0006] Preferably, the sintering temperature of the solid-state sintering method in step two is 1100-1350℃, and the holding time is 4-8h.

[0007] Preferably, in step three, the sintered sample is wrapped in carbon paper and then placed between graphite felts.

[0008] Preferably, in step three, the thickness of the graphite felt is 5-10 mm, and the width is 1.5-2 times the diameter of the sample.

[0009] Preferably, the current intensity in step four is 17-26A.

[0010] The present invention also protects a titanate-based ceramic prepared by the method described above and its application in electronic devices.

[0011] Compared with the prior art, the present invention has the following technical effects: This invention further applies vacuum ultrafast heating to the ceramic sheet based on traditional sintering, using short-time vacuum high temperature to further improve the dielectric properties of the original ceramic sheet, thereby reducing high-temperature leakage. This invention is simple to operate, has a short vacuum ultra-fast heating time, greatly improves production efficiency, saves costs, and avoids environmental pollution, thus achieving green production. Attached Figure Description

[0012] Figure 1 The dielectric properties of the titanate-based ceramics of Example 1 of this invention are shown in the conventional sintering and conventional sintering + ultrafast vacuum sintering diagrams. Figure 2This is a graph showing the relationship between the conductivity and temperature of the titanate-based ceramic in Example 1 of the present invention. Detailed Implementation

[0013] The following detailed explanation of the specific content of the present invention is provided in conjunction with embodiments. These descriptions are intended to explain the present invention and not to limit it.

[0014] Example 1 This embodiment provides a method for preparing titanate-based ceramics, including the following steps: Step 1: According to 98wt% Ba 0.5 Sr 0.5 Weigh out the raw materials: TiO3, 1 wt% MgO and 1 wt% K2O; Step 2: After mixing the raw materials weighed in Step 1 to prepare a sample, sinter it using the solid-state method at a sintering temperature of 1250℃ and a holding time of 5h. Step 3: Wrap the sintered sample in carbon paper and place it between graphite felts. Then, place it in a sealed pressure chamber and evacuate it until the pressure is below -0.095 MPa. The graphite felt should be 8 mm thick and 1.6 times the diameter of the sample. Step 4: Apply a 20A current to the sample to generate Joule heating, rapidly heat it to 1000℃ at a heating rate of 30℃ / min, hold it at that temperature for 60s, then turn off the power and remove the vacuum after the sample has cooled down.

[0015] Figure 1 Dielectric property diagrams of barium titanate-based ceramics obtained by conventional sintering and conventional sintering combined with vacuum ultrafast heating, with the addition of fluxes magnesium oxide and potassium oxide, show that the high-temperature dielectric loss of conventional sintering combined with vacuum ultrafast heating is lower than that of conventional sintering. Figure 2 The electrical conductivity versus temperature obtained by conventional sintering and conventional sintering plus vacuum ultrafast heating after adding fluxes magnesium oxide and potassium oxide to barium titanate-based ceramics is shown in the graphs. Conventional sintering plus vacuum ultrafast heating suppresses high-temperature leakage.

[0016] Example 2 This embodiment provides a method for preparing titanate-based ceramics, including the following steps: Step 1: Weigh the raw materials according to the following composition: 99.6 wt% BaTiO3 and 0.04 wt% ZnO; Step 2: After mixing the raw materials weighed in Step 1 to prepare the sample, sinter it using the solid-state method at a sintering temperature of 1100℃ and a holding time of 8h. Step 3: Wrap the sintered sample in carbon paper and place it between graphite felts. Then, place it in a sealed pressure chamber and evacuate it until the pressure is below -0.095 MPa. The graphite felt should be 5 mm thick and twice the diameter of the sample. Step 4: Apply a 17A current to the sample to generate Joule heating, rapidly heat it to 1500℃ at a heating rate of 80℃ / min, hold it at that temperature for 30s, then turn off the power and remove the vacuum after the sample has cooled down.

[0017] Example 3 This embodiment provides a method for preparing titanate-based ceramics, including the following steps: Step 1: According to 70wt% Ba 0.7 Ca 0.3 Weigh out the raw materials: TiO3, 20wt% MgO and 10wt% Y2O3; Step 2: After mixing the raw materials weighed in Step 1 to prepare the sample, sinter it using the solid-state method at a sintering temperature of 1350℃ and a holding time of 4h. Step 3: Wrap the sintered sample in carbon paper and place it between graphite felts. Then, place it in a sealed pressure chamber and evacuate it until the pressure is below -0.095 MPa. The graphite felt should be 10 mm thick and 1.5 times the diameter of the sample. Step 4: Apply a 26A current to the sample to generate Joule heating, rapidly heat it to 1200℃ at a heating rate of 80℃ / min, hold it at that temperature for 180s, then turn off the power and remove the vacuum after the sample has cooled down.

[0018] Example 4 This embodiment provides a method for preparing titanate-based ceramics, including the following steps: Step 1: Weigh the raw materials according to the following composition: 80wt% SrTiO3, 10wt% Li2O, 5wt% Na2O and 5wt% Y2O3. Step 2: After mixing the raw materials weighed in Step 1 to prepare the sample, sinter it using the solid-state method at a sintering temperature of 250℃ and a holding time of 4h. Step 3: Wrap the sintered sample in carbon paper and place it between graphite felts. Then, place it in a sealed pressure chamber and evacuate it until the pressure is below -0.095 MPa. The graphite felt should be 5 mm thick and twice the diameter of the sample. Step 4: Apply an 18A current to the sample to generate Joule heating, rapidly heat it to 1350℃ at a heating rate of 40℃ / min, hold it at that temperature for 50s, then turn off the power and remove the vacuum after the sample has cooled down.

[0019] Example 5 This embodiment provides a method for preparing titanate-based ceramics, including the following steps: Step 1: According to 90wt% Ba 0.3 Sr 0.5 Ca 0.2 The raw materials are weighed as TiO3, 6wt% MgO and 4wt% ZnO; Step 2: After mixing the raw materials weighed in Step 1 to prepare the sample, sinter it using the solid-state method at a sintering temperature of 1100℃ and a holding time of 4h. Step 3: Wrap the sintered sample in carbon paper and place it between graphite felts. Then, place it in a sealed pressure chamber and evacuate it until the pressure is below -0.095 MPa. The graphite felt should be 5 mm thick and twice the diameter of the sample. Step 4: Apply a 22A current to the sample to generate Joule heating, and rapidly heat it to 900℃ at a heating rate of 50℃ / min. Hold the temperature for 30-180s, then turn off the power. After the sample cools down, remove the vacuum.

[0020] The titanate-based ceramics of this invention are used in electronic components such as high-temperature ceramic capacitors, power device packages, and sensors, exhibiting low dielectric loss and high safety and reliability.

[0021] This invention is simple to operate, has a short vacuum ultra-fast heating time, greatly improves production efficiency, saves costs, and avoids environmental pollution, thus achieving green production.

[0022] The above-described specific embodiments are merely illustrative explanations of the present invention and do not constitute any limitation on the scope of protection of the present invention. Those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing titanate-based ceramics, characterized in that, Includes the following steps: Step 1: Weigh the raw materials according to the general structural formula (1-x)ATiO3-xM; wherein, A includes at least one of the elements Ba, Sr, Ca, and Mg, M includes at least one of MgO, ZnO, Li2O, Na2O, K2O, and Y2O3, and x takes a value of 0.04wt%-30wt%; Step 2: After mixing the raw materials weighed in Step 1 to prepare a sample, sinter it using a solid-state method. Step 3: Place the sintered sample between graphite felts and place it in a sealed pressure chamber to evacuate until the pressure is below -0.095 MPa; Step 4: Apply an electric current to the sample to generate Joule heating, rapidly heating it to 900-1500℃ at a heating rate of 30-80℃ / min. Hold the temperature for 30-180 seconds, then turn off the power. After the sample cools down, remove the vacuum.

2. The method for preparing titanate-based ceramics as described in claim 1, characterized in that, In step one, x takes values ​​ranging from 0.04wt% to 10wt%.

3. The method for preparing titanate-based ceramics as described in claim 1, characterized in that, The solid-state sintering process described in step two involves a sintering temperature of 1100-1350℃ and a holding time of 4-8 hours.

4. The method for preparing titanate-based ceramics as described in claim 1, characterized in that, In step three, the sintered sample is wrapped in carbon paper and placed between graphite felts.

5. The method for preparing titanate-based ceramics as described in claim 1, characterized in that, In step three, the thickness of the graphite felt is 5-10 mm, and the width is 1.5-2 times the diameter of the sample.

6. The method for preparing titanate-based ceramics as described in claim 1, characterized in that, The current intensity mentioned in step four is 17-26A.

7. A titanate-based ceramic prepared by the method according to any one of claims 1 to 6.

8. The application of a titanate-based ceramic as described in claim 7 in electronic devices.

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