High-temperature dielectric frequency sensitive ceramic material, preparation method thereof and dielectric sensitive element
Dielectric frequency-sensitive ceramic materials prepared by multi-element doping of Ba, Sn and Zn have solved the problems of dielectric property degradation and frequency sensitivity loss under high temperature environment, and have achieved sensitive response to frequency changes at high temperature, making them suitable for high temperature electronic devices and sensors.
Patent Information
- Application Number
- CN202511452956.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-13
- Publication Date
- 2026-01-13
AI Technical Summary
Traditional dielectric materials suffer from dielectric degradation and loss of frequency sensitivity at high temperatures, making it difficult to meet the needs of modern electronic devices.
A dielectric sensitive element was prepared using a multi-element doped ceramic material of Ba0.225Na0.3875Bi0.3875Sn0.225Ti0.775ZnxO3 through ball milling, pre-firing, cold isostatic pressing and sintering processes. Combined with silver electrode coating, frequency sensitivity at high temperature was achieved.
Within a temperature range of 200-400℃ and a frequency range of 0.1kHz-1MHz, the dielectric constant changes by more than 200 with frequency, exhibiting significant high-temperature frequency sensitivity, making it suitable for high-temperature electronic devices and sensors.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of functional ceramic materials, and particularly relates to a dielectric frequency sensitive ceramic material at high temperature, a preparation method thereof and a dielectric sensitive element. BACKGROUND
[0002] With the development of electronic technology towards high temperature, high frequency and multi-frequency adaptation, higher requirements are put forward for dielectric materials. Traditional dielectric materials often show problems such as dielectric performance degradation and loss of frequency sensitivity in high temperature environment, and are difficult to meet the needs of modern electronic devices.
[0003] At present, known high-temperature dielectric materials mainly include barium titanate-based, sodium bismuth titanate-based and stannate-based systems. Most of the current research focuses on dielectric temperature stability, and few researchers focus on dielectric frequency sensitivity, which has a wide range of applications in high-frequency capacitors and sensors. SUMMARY
[0004] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a dielectric frequency sensitive ceramic material at high temperature, a preparation method thereof and a dielectric sensitive element, which solves the problems of dielectric performance degradation and loss of frequency sensitivity of existing dielectric materials in high temperature environment.
[0005] The present application is realized by the following technical solutions: A dielectric frequency sensitive ceramic material at high temperature, chemical formula is Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn x O3, wherein x is the molar doping amount of Zn, 0.03≤x≤0.1.
[0006] A preparation method of a dielectric frequency sensitive ceramic material at high temperature, comprising the following steps: 1) The chemical raw materials BaCO3, Na2CO3, Bi2O3, SnO2, TiO2 and ZnO are weighed and prepared according to the stoichiometric formula Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn x O3; 2) The chemical raw materials prepared in step 1) are ball milled and mixed, anhydrous ethanol and zirconium balls are used as the ball milling medium, and the ball milling is carried out for 12-24 hours; 3) The mixture after ball milling in step 2) is dried and pre-fired at 800-900°C for 2-4 hours to obtain a pre-fired powder; 4) The pre-sintered powder of step 3) is ball-milled again with anhydrous ethanol and zirconium balls as the ball-milling medium, dried after ball-milling for 12-24 hours, and sieved to form a sieved material; 5) The sieved material of step 4) is added with a binder and cold isostatic pressed, sintered at 1150-1250°C for 2-4 hours to obtain the high-temperature dielectric frequency sensitive ceramic material.
[0007] Further, the mass ratio of the chemical raw materials: anhydrous ethanol: zirconium balls in the ball-milling of step 2) is (0.8-1.2):(1.8-2.2):(4.8-5.2); and the mass ratio of the pre-sintered powder: anhydrous ethanol: zirconium balls in the ball-milling of step 4) is (0.8-1.2):(1.8-2.2):(4.8-5.2).
[0008] Further, the mesh size of the sieving in step 4) is 80-200 mesh.
[0009] Further, the cold isostatic pressing in step 5) is at 200 MPa, and the mass ratio of the sieved material to the binder is 100:(3-5).
[0010] Further, the binder is polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose or polyvinylidene fluoride.
[0011] Further, the sintering in step 5) adopts traditional sintering, the heating rate is 5-10°C / min, and the same proportion of chemical raw material powder as in step 1) is covered during the sintering process to prevent element volatilization.
[0012] A dielectric sensitive element, the high-temperature dielectric frequency sensitive ceramic material is coated with a silver electrode, and the silver coating is sintered to obtain.
[0013] Further, the silver sintering temperature is 500-800°C, and the holding time is 15-30 min.
[0014] Compared with the prior art, the present application has the following beneficial effects: The present application has a significant high-temperature frequency sensitivity, and by the multi-element synergistic doping of Ba, Sn and Zn based on sodium bismuth titanate, the sensitive response to the frequency change at high temperature is realized, Ba 2+ mainly replaces Na at A site + or Bi 3+ , the ionic radius of Ba 2+ is different from that of Na + , Bi 3+ , and Ba 2+Doping with Sn introduces lattice distortion and stress, destroying the original strong ferroelectricity of NBT and transforming it into a relaxor ferroelectric. The characteristic of a relaxor ferroelectric is that its dielectric constant peak becomes broad and shifts with frequency. 4+ Zn 2+ Ti replacing B 4+ This process weakens the ferroelectricity of the material, shifts the Curie temperature to lower temperatures, and makes the dielectric peak more diffuse. This "softening" effect enhances the material's relaxation properties and further promotes frequency dependence. Furthermore, the introduction of chemical disorder at the B-site leads to microscopic compositional fluctuations that result in different Curie temperatures in different regions, thus broadening the dielectric response macroscopically and making it frequency-sensitive over a wide temperature range. In this invention, the dielectric constant changes by more than 200 with frequency in the temperature range of 200-400℃ and the frequency range of 0.1kHz-1MHz. By adjusting the Zn doping amount x, the dielectric frequency sensitivity and other electrical properties of the material can be precisely controlled. The high-temperature dielectric frequency-sensitive ceramic material prepared by this invention is suitable for high-temperature electronic devices, sensors, and multi-frequency adaptive systems.
[0015] This invention uses the traditional solid-phase reaction method, which is mature, low-cost, and easy to scale up for production. Attached Figure Description
[0016] Figure 1 The graphs show the dielectric constant of the ceramic materials prepared in Examples 1-4 of this invention as a function of frequency at different temperatures. Detailed Implementation
[0017] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.
[0018] Example 1 A high-temperature dielectric frequency-sensitive ceramic material with the chemical formula Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.03 O3.
[0019] A type of Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.03 The specific steps for preparing O3 ceramic materials are as follows: 1) Weigh out barium carbonate (BaCO3), sodium carbonate (Na2CO3), bismuth oxide (Bi2O3), tin oxide (SnO2), titanium oxide (TiO2), and zinc oxide (ZnO) precisely according to their stoichiometric ratios; 2) Single ball milling: Mix the raw material with anhydrous ethanol and zirconium oxide in a ball mill for 12 hours. The mass ratio of chemical raw material, anhydrous ethanol and zirconium balls during ball milling is 1:2:5. 3) Pre-calcination treatment: The ball-milled mixture was pre-calcined at 850°C for 3 hours to obtain pre-calcined powder; 4) Secondary ball milling: The pre-calcined powder is ball milled again for 12 hours. The chemical raw materials for ball milling are anhydrous ethanol and zirconium balls in a mass ratio of 1:2:5. After passing through a 100-mesh sieve, the sieved material is formed. 5) Molding and sintering: After drying the powder after secondary ball milling, polyvinyl alcohol binder is added to granulate the powder, which is then pressed into shape and sintered at 1180°C for 3 hours. The sintering is carried out using conventional sintering with a heating rate of 8°C / min. During the sintering process, the powder is covered with chemical raw material powder in the same proportion as in step 1) to prevent element volatilization, thus obtaining a dielectric frequency sensitive ceramic material at high temperature.
[0020] The obtained materials were subjected to performance tests, such as: Figure 1 As shown in (a), in the high-temperature region close to 500°C, the dielectric constant (Permittivity) values at different frequencies are still in a high range (e.g., some curves can still reach above 1300 at high temperatures), which indicates that the material still has a strong ability to store electrical energy in a high-temperature environment.
[0021] Example 2 A high-temperature dielectric frequency-sensitive ceramic material with the chemical formula Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.05 O3.
[0022] Preparation of Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.05 For O3 ceramic material, the steps are the same as in Example 1, except that the amount of ZnO is adjusted to 0.05.
[0023] The obtained material was subjected to performance testing, and the results are as follows: Figure 1 As shown in (b), the dielectric constant of the ceramic sample increases with the increase of doping amount and the relaxation characteristics are enhanced. Under high temperature conditions, its dielectric constant becomes more sensitive with the increase of frequency, and its change is between 100 and 200.
[0024] Example 3 A high-temperature dielectric frequency-sensitive ceramic material with the chemical formula Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.07 O3.
[0025] Preparation of Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.07 The O3 ceramic material is prepared using the same steps as in Example 1, except that the amount of ZnO is adjusted to 0.07.
[0026] The obtained material was subjected to performance testing, and the results are as follows: Figure 1 As shown in (c), the ceramic sample exhibits outstanding dielectric sensitivity; when the frequency increases by an order of magnitude, the dielectric constant changes by more than 200.
[0027] Example 4 A high-temperature dielectric frequency-sensitive ceramic material with the chemical formula Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.10 O3.
[0028] Preparation of Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.10 For O3 ceramic material, the steps are the same as in Example 1, except that the amount of ZnO is adjusted to 0.10.
[0029] The obtained material was subjected to performance testing, and the results are as follows: Figure 1 As shown in (d), the dielectric sensitivity of the ceramic sample remains stable.
[0030] Performance Comparison Analysis Comparative analysis of the performance of the above examples reveals that the frequency sensitivity mechanism originates from the strong relaxation of defect dipoles and polar nanoregions (PNRs). Zn suppresses oxygen vacancies, making the frequency response of PNRs dominant rather than ionic conductivity at high temperatures. Figure 1As shown, the horizontal axis represents temperature, the left vertical axis represents dielectric constant, and the right horizontal axis represents dielectric loss. Different colors represent different frequencies, increasing exponentially with the arrows, specifically 1 kHz, 10 kHz, 100 kHz, and 1000 kHz. It can be observed that when the ZnO content increases to 0.05%, the dielectric constant changes significantly with increasing frequency at high temperatures. This indicates that the introduction of Zn significantly enhances the dielectric frequency sensitivity of the material at high temperatures while reducing dielectric loss. When the Zn doping concentration is 0.07~0.1%, the material exhibits the best overall performance; when the frequency increases by an order of magnitude, the dielectric constant changes by more than 200. As a lead-free material, this invention solves the environmental compatibility problem of materials such as PMN-PT; as a high-temperature material, it compensates for the insufficient high-temperature performance of systems such as KNN and PMN-PT, making it very suitable for application in next-generation high-temperature electronic devices and sensors. Therefore, compared with other materials, the advantage of this invention is not that it leads in all indicators, but rather that it achieves the best balance at the intersection of the three key dimensions of "high temperature," "lead-free," and "frequency sensitivity," demonstrating irreplaceable application potential. This indicates that the material has potential applications in the field of high-temperature frequency sensing.
[0031] Example 5 A high-temperature dielectric frequency-sensitive ceramic material with the chemical formula Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.04 O3.
[0032] A type of Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.04 The specific steps for preparing O3 ceramic materials are as follows: 1) Weigh out barium carbonate (BaCO3), sodium carbonate (Na2CO3), bismuth oxide (Bi2O3), tin oxide (SnO2), titanium oxide (TiO2), and zinc oxide (ZnO) precisely according to their stoichiometric ratios; 2) Single ball milling: The raw material is mixed with anhydrous ethanol and zirconium oxide by ball milling for 20 hours. The mass ratio of chemical raw material: anhydrous ethanol: zirconium balls during ball milling is 0.8:1.8:4.8. 3) Pre-calcination treatment: The ball-milled mixture was pre-calcined at 800°C for 2 hours to obtain pre-calcined powder; 4) Secondary ball milling: The pre-calcined powder is ball milled again for 20 hours. The chemical raw materials used in the ball milling are anhydrous ethanol and zirconium balls in a mass ratio of 0.8:1.8:4.8. The powder is then passed through an 80-mesh sieve to form sieved material. 5) Molding and sintering: After drying the powder after secondary ball milling, polyethylene glycol binder is added to granulate the powder, which is then pressed into shape and sintered at 1150°C for 2 hours. The sintering is carried out using conventional sintering with a heating rate of 5°C / min. During the sintering process, the powder is covered with chemical raw material powder in the same proportion as in step 1) to prevent element volatilization, thus obtaining a dielectric frequency sensitive ceramic material at high temperature.
[0033] A dielectric sensitive element is obtained by coating a high-temperature dielectric frequency sensitive ceramic material with a silver electrode and then firing it with silver; the firing temperature is 500°C and the holding time is 15 minutes.
[0034] Example 6 A high-temperature dielectric frequency-sensitive ceramic material with the chemical formula Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.06 O3.
[0035] A type of Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.06 The specific steps for preparing O3 ceramic materials are as follows: 1) Weigh out barium carbonate (BaCO3), sodium carbonate (Na2CO3), bismuth oxide (Bi2O3), tin oxide (SnO2), titanium oxide (TiO2), and zinc oxide (ZnO) precisely according to their stoichiometric ratios; 2) Single ball milling: The raw material is mixed with anhydrous ethanol and zirconium oxide by ball milling for 24 hours. The mass ratio of chemical raw material: anhydrous ethanol: zirconium balls during ball milling is 1.2:2.2:5.2. 3) Pre-calcination treatment: The ball-milled mixture was pre-calcined at 900°C for 4 hours to obtain pre-calcined powder; 4) Secondary ball milling: The pre-calcined powder is ball milled again for 24 hours. The chemical raw materials for ball milling are anhydrous ethanol and zirconium balls in a mass ratio of 1.2:2.2:5.2. After passing through a 200-mesh sieve, the sieved material is formed. 5) Molding and sintering: After drying the powder after secondary ball milling, carboxymethyl cellulose binder is added to granulate the powder, which is then pressed into shape and sintered at 1250°C for 4 hours. The sintering is carried out using conventional sintering with a heating rate of 10°C / min. During the sintering process, the powder is covered with chemical raw material powder in the same proportion as in step 1) to prevent element volatilization, thus obtaining a dielectric frequency sensitive ceramic material at high temperature.
[0036] A dielectric sensitive element is obtained by coating a high-temperature dielectric frequency sensitive ceramic material with a silver electrode and then firing it with silver; the firing temperature is 650°C and the holding time is 20 minutes.
[0037] Example 7 A high-temperature dielectric frequency-sensitive ceramic material with the chemical formula Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.08 O3.
[0038] A type of Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn 0.08 The specific steps for preparing O3 ceramic materials are as follows: 1) Weigh out barium carbonate (BaCO3), sodium carbonate (Na2CO3), bismuth oxide (Bi2O3), tin oxide (SnO2), titanium oxide (TiO2), and zinc oxide (ZnO) precisely according to their stoichiometric ratios; 2) Single ball milling: The raw material is mixed with anhydrous ethanol and zirconium oxide by ball milling for 18 hours. The mass ratio of chemical raw material: anhydrous ethanol: zirconium balls during ball milling is 0.8:2.2:4.8. 3) Pre-calcination treatment: The ball-milled mixture was pre-calcined at 820°C for 2.5 hours to obtain pre-calcined powder; 4) Secondary ball milling: The pre-calcined powder is ball milled again for 18 hours. The chemical raw materials used in the ball milling are anhydrous ethanol and zirconium balls in a mass ratio of 0.8:2.2:4.8. The powder is then passed through a 150-mesh sieve to form sieved material. 5) Molding and sintering: After drying the powder after secondary ball milling, polyvinylidene fluoride binder is added to granulate the powder, which is then pressed into shape and sintered at 1200°C for 2.5 hours. The sintering is carried out using conventional sintering with a heating rate of 9°C / min. During the sintering process, the powder is covered with chemical raw material powder in the same proportion as in step 1) to prevent element volatilization, thus obtaining a dielectric frequency sensitive ceramic material at high temperature.
[0039] A dielectric sensitive element is obtained by coating a high-temperature dielectric frequency sensitive ceramic material with a silver electrode and then firing it with silver; the firing temperature is 800°C and the holding time is 30 minutes.
Claims
1. A dielectric frequency-sensitive ceramic material for high temperatures, characterized in that, The chemical formula is Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn x O3, where x is the molar doping amount of Zn, 0.03≤x≤0.
1.
2. A method for preparing a high-temperature dielectric frequency-sensitive ceramic material as described in claim 1, characterized in that, Includes the following steps: 1) Mix the chemical raw materials BaCO3, Na2CO3, Bi2O3, SnO2, TiO2, and ZnO according to the stoichiometric formula Ba 0.225 Na 0.3875 Bi 0.3875 Sn 0.225 Ti 0.775 Zn x O3 is used for weighing and mixing ingredients; 2) Mix the chemical raw materials prepared in step 1) by ball milling, using anhydrous ethanol and zirconium balls as the ball milling media, and ball mill for 12-24 hours; 3) After drying the mixture after ball milling in step 2), pre-calcinate it at 800-900°C for 2-4 hours to obtain pre-calcined powder; 4) The pre-calcined powder described in step 3) is ball-milled again, using anhydrous ethanol and zirconium balls as the ball-milling media. After ball-milling for 12-24 hours, it is dried and sieved to form sieved material. 5) Add a binder to the sieved material obtained in step 4) and cold isostatically press it into shape. Sinter it at 1150-1250°C for 2-4 hours to obtain a high-temperature dielectric frequency sensitive ceramic material.
3. The method for preparing high-temperature dielectric frequency-sensitive ceramic material according to claim 2, characterized in that, In step 2), the mass ratio of the chemical raw materials used in ball milling is (0.8-1.2):(1.8-2.2):(4.8-5.2) for anhydrous ethanol to zirconium balls; in step 4), the mass ratio of the pre-calcined powder used in ball milling is (0.8-1.2):(1.8-2.2):(4.8-5.2) for anhydrous ethanol to zirconium balls.
4. The method for preparing high-temperature dielectric frequency-sensitive ceramic material according to claim 2, characterized in that, In step 4), the sieve mesh size is 80-200 mesh.
5. The method for preparing high-temperature dielectric frequency-sensitive ceramic material according to claim 2, characterized in that, In step 5), the material is cold isostatically pressed at 200 MPa, and the mass ratio of the sieved material to the binder is 100:(3-5).
6. The method for preparing high-temperature dielectric frequency-sensitive ceramic material according to claim 5, characterized in that, The adhesive is polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose, or polyvinylidene fluoride.
7. The method for preparing high-temperature dielectric frequency-sensitive ceramic material according to claim 2, characterized in that, The sintering in step 5) adopts conventional sintering with a heating rate of 5-10°C / minute, and is covered with chemical raw material powder in the same proportion as in step 1) during the sintering process to prevent element volatilization.
8. A dielectric sensing element, characterized in that, The high-temperature dielectric frequency sensitive ceramic material is coated with a silver electrode and then calcined to obtain the product.
9. A dielectric sensing element according to claim 8, characterized in that, The silver firing temperature is 500~800°C, and the holding time is 15~30 minutes.