Titanium dioxide filler for improving dielectric properties of ceramics and method for preparing the same

Abstract

The application relates to the field of titanium white powder, and aims to solve the problem that the dielectric performance of a product is not improved well when existing titanium dioxide is used as a functional filler of ceramics, and provides a preparation method of titanium white powder for improving the dielectric performance of ceramics, which comprises the following steps: S100, adding a doped ion solution into a precursor solution of titanium dioxide under heating condition to obtain a gel; the doped ion solution comprises Mo 6+ and Sn 2+ ; the molar ratio of Mo 6+ to Ti 4+ is (10-30):(1-2), and the molar ratio of Sn 2+ to Ti 4+ is (10-20):(2-3); S200, the gel is used to prepare titanium white powder through a calcination process. The application utilizes the crystal type change of anatase titanium dioxide in the early sintering stage to reduce the possibility of ceramic microcracks; the application avoids aggravating volume shrinkage under high-temperature sintering, so that the possibility of ceramic structure defects is increased under the same process condition; and the titanium white powder prepared through the titanium dioxide doping process can promote the conversion of the titanium white powder to rutile titanium dioxide.

Description

Technical Field

[0001] This invention relates to the field of titanium dioxide, and more specifically, to a titanium dioxide filler for improving the dielectric properties of ceramics and its preparation method. Background Technology

[0002] Dielectric ceramics are important electronic ceramics with excellent insulation and dielectric properties, and are widely used in electronics, communications, and other fields. Rutile titanium dioxide has a high dielectric constant, and when added to ceramic systems with low dielectric constants, it can improve the dielectric constant of the ceramic to a certain extent. However, the difference in the coefficients of thermal expansion between titanium dioxide and ceramic raw materials can easily lead to structural defects during the ceramic sintering process, thus affecting the overall dielectric properties of the ceramic. The dispersion and compatibility of titanium dioxide in the matrix also affect the dielectric properties of the final product. Summary of the Invention

[0003] The purpose of this invention is to provide a titanium dioxide filler for improving the dielectric properties of ceramics and its preparation method, thereby solving the problem that when titanium dioxide is used as a functional filler for ceramics, the difference in thermal expansion coefficient between it and the raw materials leads to structural defects during the sintering process, resulting in poor improvement of the dielectric properties of the product.

[0004] The embodiments of the present invention are achieved through the following technical solutions:

[0005] A method for preparing titanium dioxide filler to improve the dielectric properties of ceramics, comprising:

[0006] S100. Under heating conditions, a doped ion solution is added to a titanium dioxide precursor solution to obtain a gel; the doped ion solution includes: Mo. 6+ and Sn 2+ ;The Mo 6+ With Ti 4+ The molar ratio of Sn is (10-30):(1-2). 2+ With Ti 4 + The molar ratio is (10-20):(2-3);

[0007] S200, The gel is prepared as titanium dioxide filler by calcination process.

[0008] The concentration of the precursor solution can be selected from 18wt% to 25wt%; the solvent of the precursor solution can be deionized water or alcohol, such as ethanol or n-octanol.

[0009] High-dielectric ceramics play a crucial role in electronic components such as capacitors and filters. Utilizing their high dielectric constant, component size can be reduced, energy storage density increased, and response speed improved, meeting the miniaturization and integration requirements of modern electronic devices. High-dielectric ceramics also serve as potential energy storage materials, possessing advantages such as high energy storage density and fast charge / discharge speeds, and are expected to play a significant role in future energy storage systems. The sensitivity of high-dielectric ceramics to changes in electric fields makes them important materials for sensors, capable of detecting and converting changes in electric fields into measurable signals. However, the manufacturing cost of high-dielectric ceramics is relatively high. When the application scenario does not require an excessively high dielectric constant, or even does not need to reach the dielectric constant of rutile ceramics, a certain amount of high-dielectric functional filler can be added to relatively inexpensive raw materials to improve the dielectric constant to a certain extent, ensuring that production costs are not significantly increased.

[0010] Titanium dioxide has a high dielectric constant, making it suitable as a functional filler in dielectric ceramics. Its addition also effectively improves the mechanical properties of ceramics. Ceramic raw materials generally consist of silicon dioxide, alumina, zirconium oxide, barium carbonate, magnesium oxide, and organic matrices. When adding inorganic fillers, the difference in thermal expansion coefficients between the filler and the other components must be considered to avoid surface quality defects during sintering and to prevent high dielectric losses due to low compatibility of the inorganic filler. Therefore, the amount of inorganic filler used is limited. Furthermore, ceramic firing is a densification process, involving not only changes in the volume of raw material particles but also the filling of pores in the ceramic body. During firing, the volume of ceramics typically shrinks. The sintering process generally includes a preheating stage, an oxidation stage, and a firing stage. The oxidation stage temperature is around 950℃, while the firing stage temperature for high-performance ceramics is generally above 1200℃, and can even reach above 2000℃. The coefficient of thermal expansion of silicon dioxide decreases with increasing temperature during firing, and becomes essentially stable above 1200℃. Commonly used titanium dioxide is primarily anatase and rutile, with rutile having a lower coefficient of thermal expansion than anatase. However, regardless of whether it is anatase or rutile, its coefficient of thermal expansion is higher than that of common raw materials such as silicon dioxide. Therefore, the applicant is considering how to reduce the difference in thermal expansion between titanium dioxide and other raw materials during ceramic firing, thereby reducing stress within the ceramic body.

[0011] Although rutile titanium dioxide has higher stability and dielectric constant than anatase titanium dioxide, and a smaller coefficient of thermal expansion, theoretically, incorporating rutile titanium dioxide into the raw materials during firing would be more advantageous for improving product performance and ensuring appearance quality. However, the applicant hopes to improve the ceramic sintering process by utilizing the shrinkage during the transformation of anatase titanium dioxide into rutile titanium dioxide. In the early stages of sintering, especially during the heating period, the ceramic volume expands to a certain extent. After reaching a sufficiently high temperature, the disappearance of pores and the filling of voids begin to cause significant volume shrinkage. The applicant hopes that titanium dioxide can undergo crystal transformation in the early stages of sintering, thereby compensating for the stress generated by spatial compression during expansion through titanium dioxide shrinkage. This could reduce the possibility of fine cracks in the ceramic, thus allowing for a certain increase in the amount of titanium dioxide used, thereby improving the dielectric constant of the ceramic. Furthermore, since titanium dioxide completes its crystal transformation in the early stages of sintering, the overall shrinkage rate of the ceramic volume will not be accelerated by titanium dioxide shrinkage in the later stages of sintering, thus reducing the possibility of cracks appearing in the later stages of sintering and expanding the range of process parameters. Currently, the volume shrinkage of most ceramics during sintering occurs after 1000℃. The temperature at which anatase titanium dioxide begins to transform into rutile is around 800℃. However, the time required to rise from 800℃ to 1000℃ during sintering is relatively short, making complete crystal transformation difficult at temperatures between 800℃ and 1000℃. Therefore, the applicant aims to lower the temperature at which anatase titanium dioxide transforms into rutile. The applicant has promoted this transformation through a doping process. Simultaneously, to control the transformation and prevent excessively rapid volume change during the heating phase, which could lead to microcracks, the applicant has experimentally controlled the doping amount. Furthermore, excessive doping can lead to uncontrolled grain growth and increased structural defects, affecting not only the dielectric constant but also the mechanical properties and chemical stability of the product.

[0012] Preferably, the titanium dioxide precursor solution includes one or more of the following: tetrabutyl titanate solution, titanium oxysulfate solution, tetraisopropyl titanate solution, and titanium tetrachloride solution.

[0013] Preferably, the temperature of the reaction system in S100 is 60℃-80℃, and the pH value is 7.5-9.

[0014] pH can be adjusted using ammonia. Appropriate system temperature and pH are beneficial for the entry of metal ions into the titanium dioxide lattice, the completion of precursor solution hydrolysis, and the stability of hydrolysis products.

[0015] Preferably, S200 includes:

[0016] A100, the gel is calcined to obtain a pre-product;

[0017] A200. After the preproduct is coated with a film layer through a coating process, titanium dioxide filler is obtained; the volatilization temperature or decomposition temperature of the film layer is 300℃-600℃.

[0018] Because anatase titanium dioxide expands to a certain extent before transforming into rutile titanium dioxide, and its expansion coefficient is greater than that of conventional ceramic raw materials, this can lead to structural defects in the product and ultimately affect its dielectric properties. Therefore, this invention coats titanium dioxide with a film layer. This film layer restricts the expansion of titanium dioxide and also provides expansion space for titanium dioxide through the decomposition or volatilization of the film layer. Thus, the temperature at which the film layer breaks down in this invention is lower than the crystal transformation temperature of anatase titanium dioxide.

[0019] Preferably, the coating process includes: mixing and reacting 1-4 parts by weight of triethanolamine, 1.5-5 parts by weight of coupling agent and 80-100 parts by weight of preproduct, and then drying to obtain titanium dioxide filler.

[0020] In the early-stage ceramic forming process, to ensure morphological stability, the selection of film material can improve the dispersibility of titanium dioxide and enhance the bonding between titanium dioxide and organic binders during the forming process. Coupling agents can further improve film stability, thereby increasing the decomposition temperature to 400℃-600℃.

[0021] Preferably, the reaction temperature of the coating process is 65℃-85℃, and the reaction time is 0.8h-2h.

[0022] By controlling the amount of raw materials, reaction temperature, and reaction time, the film thickness can be controlled, preventing the film from becoming too large and thus avoiding excessive porosity in the molded preform, excessive volume shrinkage after high-temperature sintering, and prolonged densification process time. Conversely, a film thickness that is too small is unsuitable for the expansion process before the transformation of anatase titanium dioxide. The applicant's experiments have shown that the product using the parameters of this invention exhibits superior performance.

[0023] Preferably, the coupling agent comprises one or more of the following: isopropyl triisostearoyl titanate, GR-501, and KH570.

[0024] Experiments showed that the product prepared using isopropyl triisostearoyl titanate has good performance.

[0025] Preferably, S100 includes:

[0026] Dissolve phosphomolybdic acid in ethanol to obtain solution A;

[0027] Solution B is obtained by dissolving tin tetrachloride in ethanol;

[0028] Under heating conditions, solutions A and B were added to the titanium dioxide precursor solution and mixed under ultrasonic conditions for 10-30 minutes. The mixture was then allowed to stand at room temperature for 8-12 hours to obtain a gel. The ultrasonic frequency was 20-30 kHz.

[0029] Preferably, solution B is added to the titanium dioxide precursor solution all at once, and then solution A is added gradually.

[0030] During the doping experiment, the applicant discovered that when both solution A and solution B were added to the precursor solution simultaneously or gradually, Sn... 4+ The applicant hypothesizes that the limited doping amount is due to competition between the two types of ions during the doping process.

[0031] The present invention has at least the following beneficial effects:

[0032] This invention utilizes the crystal form change of anatase titanium dioxide in the early stage of sintering to reduce the possibility of microcracks in ceramics. Anatase titanium dioxide can complete its transformation to rutile form before high-temperature sintering, avoiding further shrinkage under the already high volume shrinkage rate of high-temperature sintering, which would increase the possibility of structural defects in ceramics under the same process conditions. Titanium dioxide produced through a doping process can promote its transformation to rutile titanium dioxide. After coating the outer surface of titanium dioxide with a film layer through a coating process, the film layer can be used to limit the expansion of titanium dioxide at low temperatures, reducing the possibility of structural defects caused by differences in thermal expansion of raw materials. The film layer volatilizes or decomposes before the titanium dioxide crystal form transformation, so that the released film layer space can be used for the expansion of titanium dioxide or the surrounding matrix, reducing internal stress. The presence of the film layer can also increase the dispersibility of titanium dioxide and its compatibility with the matrix, thereby increasing the dielectric properties of the product. Detailed Implementation

[0033] To make the objectives, methods, and advantages of the embodiments of the present invention clearer, the methods in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0034] Example 1: A method for preparing titanium dioxide filler to improve the dielectric properties of ceramics, comprising:

[0035] S100. Under heating conditions, a doped ion solution is added to a titanium dioxide precursor solution to obtain a gel; the doped ion solution includes: Mo. 6+ and Sn 4+ ;The Mo 6+ With Ti 4+ The molar ratio is 10:1, and the Sn 2+ With Ti 4+The molar ratio is 10:2; the temperature of the reaction system in S100 is 60℃, and the pH value is 7.5; the solute of the titanium dioxide precursor solution is titanium tetrachloride, the solvent is ethanol, and the concentration of titanium tetrachloride is 20wt%.

[0036] S100 includes:

[0037] Dissolve phosphomolybdic acid in ethanol to obtain solution A;

[0038] Solution B is obtained by dissolving tin tetrachloride in ethanol;

[0039] Under heating conditions, solutions A and B were added to the titanium dioxide precursor solution at one time, and after mixing under ultrasonic conditions for 10 min, the mixture was allowed to stand at room temperature for 8 h to obtain a gel; the ultrasonic frequency was 20 kHz.

[0040] S200, The gel is used to prepare titanium dioxide filler through a calcination process. The calcination temperature is 450℃ and the calcination time is 1.5h.

[0041] Example 2: A method for preparing titanium dioxide filler to improve the dielectric properties of ceramics, comprising:

[0042] S100. Under heating conditions, a doped ion solution is added to a titanium dioxide precursor solution to obtain a gel; the doped ion solution includes: Mo. 6+ and Sn 4+ ;The Mo 6+ With Ti 4+ The molar ratio is 30:2, and the Sn 2+ With Ti 4+ The molar ratio is 20:3; the temperature of the reaction system in S100 is 80℃, and the pH value is 9; the solute of the titanium dioxide precursor solution is titanium tetrachloride, the solvent is ethanol, and the concentration of titanium tetrachloride is 20wt%.

[0043] S100 includes:

[0044] Dissolve phosphomolybdic acid in ethanol to obtain solution A;

[0045] Solution B is obtained by dissolving tin tetrachloride in ethanol;

[0046] Under heating conditions, solutions A and B were added to the titanium dioxide precursor solution at one time, and after mixing under ultrasonic conditions for 30 min, the mixture was allowed to stand at room temperature for 12 h to obtain a gel; the ultrasonic frequency was 30 kHz.

[0047] S200, The gel is used to prepare titanium dioxide filler through a calcination process. The calcination temperature is 450℃ and the calcination time is 1.5h.

[0048] Example 3: A method for preparing titanium dioxide filler to improve the dielectric properties of ceramics, comprising:

[0049] S100. Under heating conditions, a doped ion solution is added to a titanium dioxide precursor solution to obtain a gel; the doped ion solution includes: Mo. 6+ and Sn 4+ ;The Mo 6+ With Ti 4+ The molar ratio is 20:1.4, and the Sn 2+ With Ti 4+ The molar ratio is 16:2.5; the temperature of the reaction system in S100 is 72℃, and the pH value is 8.3; the solute of the titanium dioxide precursor solution is titanium tetrachloride, the solvent is ethanol, and the concentration of titanium tetrachloride is 20wt%.

[0050] S100 includes:

[0051] Dissolve phosphomolybdic acid in ethanol to obtain solution A;

[0052] Solution B is obtained by dissolving tin tetrachloride in ethanol;

[0053] Under heating conditions, solutions A and B were added to the titanium dioxide precursor solution at one time, and after mixing under ultrasonic conditions for 20 min, the mixture was allowed to stand at room temperature for 10 h to obtain a gel; the ultrasonic frequency was 25 kHz.

[0054] S200, The gel is used to prepare titanium dioxide filler through a calcination process. The calcination temperature is 450℃ and the calcination time is 1.5h.

[0055] Example 4: A method for preparing titanium dioxide filler to improve the dielectric properties of ceramics, comprising:

[0056] S100. Under heating conditions, a doped ion solution is added to a titanium dioxide precursor solution to obtain a gel; the doped ion solution includes: Mo. 6+ and Sn 4+ ;The Mo 6+ With Ti 4+ The molar ratio is 20:1.4, and the Sn 2+ With Ti 4+ The molar ratio is 16:2.5; the temperature of the reaction system in S100 is 72℃, and the pH value is 8.3; the solute of the titanium dioxide precursor solution is titanium tetrachloride, the solvent is ethanol, and the concentration of titanium tetrachloride is 20wt%.

[0057] S100 includes:

[0058] Dissolve phosphomolybdic acid in ethanol to obtain solution A;

[0059] Solution B is obtained by dissolving tin tetrachloride in ethanol;

[0060] Under heating conditions, solution B was added to the titanium dioxide precursor solution in one go, and then 25 wt% solution A was added every 5 minutes. During this period, the system was in an ultrasonic environment. After 20 minutes, the system was allowed to stand at room temperature for 10 hours to obtain a gel. The ultrasonic frequency was 25 kHz.

[0061] S200, The gel is used to prepare titanium dioxide filler through a calcination process. The calcination temperature is 450℃ and the calcination time is 1.5h.

[0062] Blank example: The difference from Example 3 is that no doped ion solution was added in step S100.

[0063] Preparation method of experimental samples: Ceramic powder and binder PVA were mixed by wet ball milling for 30 hours to obtain a slurry. The amount of binder was 4% of the powder. After pressing the slurry into a blank, sintering was started. The sintering process was as follows: preheating at 300℃ for 1 hour, then heating to 1000℃ at a rate of 80℃ / h and holding for 1 hour, then heating to 1300℃ at a rate of 60℃ / h and holding for 5 hours. The ceramic powder consisted of 70wt% alumina powder, 10wt% magnesium oxide powder, 1wt% silica, and the balance titanium dioxide filler.

[0064] Experiment 1: Titanium dioxide fillers prepared according to the methods provided in Examples 1-4 and the blank example were used to prepare experimental samples. The dielectric constant of the prepared samples was then tested according to GB / T5594.4-2015 standard. The test conditions were: 1MHz, 25℃, and 5mm thickness. The average value was taken after 5 tests for each group. The test results are shown in Table 1.

[0065] Table 1

[0066] Example 1 Example 2 Example 3 Example 4 Blank example Dielectric constant 16.6 17.4 18.7 24.3 11.0

[0067] As can be seen from the comparison of the data of Examples 1-3 and the blank example in Table 1, the titanium dioxide filler prepared by titanium dioxide doping can effectively improve the dielectric constant of ceramics.

[0068] As can be seen from the data comparison between Example 3 and Example 4 in Table 1, the way solution A and solution B are added to the precursor solution affects the effect of titanium dioxide filler on improving the dielectric constant of ceramics.

[0069] Example 5: A method for preparing titanium dioxide filler to improve the dielectric properties of ceramics, comprising:

[0070] S100. Under heating conditions, a doped ion solution is added to a titanium dioxide precursor solution to obtain a gel; the doped ion solution includes: Mo. 6+ and Sn 4+ ;The Mo6+ With Ti 4+ The molar ratio is 20:1.4, and the Sn 2+ With Ti 4+ The molar ratio is 16:2.5; the temperature of the reaction system in S100 is 72℃, and the pH value is 8.3; the solute of the titanium dioxide precursor solution is titanium tetrachloride, the solvent is ethanol, and the concentration of titanium tetrachloride is 20wt%.

[0071] S100 includes:

[0072] Dissolve phosphomolybdic acid in ethanol to obtain solution A;

[0073] Solution B is obtained by dissolving tin tetrachloride in ethanol;

[0074] Under heating conditions, solution B was added to the titanium dioxide precursor solution in one go, and then 25 wt% solution A was added every 5 minutes. During this period, the system was in an ultrasonic environment. After 20 minutes, the system was allowed to stand at room temperature for 10 hours to obtain a gel. The ultrasonic frequency was 25 kHz.

[0075] S200. The gel is calcined to obtain a preproduct. The calcination temperature is 450℃ and the calcination time is 1.5h. The preproduct is coated with a film to obtain titanium dioxide filler. The coating process includes: mixing and reacting 1 part by weight of triethanolamine, 1.5 parts by weight of triisostearoyl titanate isopropyl ester, 80 parts by weight of the preproduct and 100 parts by weight of deionized water, followed by separation, washing with water and drying to obtain titanium dioxide filler. The reaction temperature is 65℃ and the reaction time is 0.8h.

[0076] Example 6: A method for preparing titanium dioxide filler to improve the dielectric properties of ceramics, comprising:

[0077] S100. Under heating conditions, a doped ion solution is added to a titanium dioxide precursor solution to obtain a gel; the doped ion solution includes: Mo. 6+ and Sn 4+ ;The Mo 6+ With Ti 4+ The molar ratio is 20:1.4, and the Sn 2+ With Ti 4+ The molar ratio is 16:2.5; the temperature of the reaction system in S100 is 72℃, and the pH value is 8.3; the solute of the titanium dioxide precursor solution is titanium tetrachloride, the solvent is ethanol, and the concentration of titanium tetrachloride is 20wt%.

[0078] S100 includes:

[0079] Dissolve phosphomolybdic acid in ethanol to obtain solution A;

[0080] Solution B is obtained by dissolving tin tetrachloride in ethanol;

[0081] Under heating conditions, solution B was added to the titanium dioxide precursor solution in one go, and then 25 wt% solution A was added every 5 minutes. During this period, the system was in an ultrasonic environment. After 20 minutes, the system was allowed to stand at room temperature for 10 hours to obtain a gel. The ultrasonic frequency was 25 kHz.

[0082] S200. The gel is calcined to obtain a preproduct. The calcination temperature is 450℃ and the calcination time is 1.5h. The preproduct is coated with a film to obtain titanium dioxide filler. The coating process includes: mixing and reacting 4 parts by weight of triethanolamine, 5 parts by weight of triisostearoyl titanate isopropyl ester, 100 parts by weight of the preproduct and 100 parts by weight of deionized water, followed by separation, washing with water and drying to obtain titanium dioxide filler. The reaction temperature is 85℃ and the reaction time is 2h.

[0083] Example 7: A method for preparing titanium dioxide filler to improve the dielectric properties of ceramics, comprising:

[0084] S100. Under heating conditions, a doped ion solution is added to a titanium dioxide precursor solution to obtain a gel; the doped ion solution includes: Mo. 6+ and Sn 4+ ;The Mo 6+ With Ti 4+ The molar ratio is 20:1.4, and the Sn 2+ With Ti 4+ The molar ratio is 16:2.5; the temperature of the reaction system in S100 is 72℃, and the pH value is 8.3; the solute of the titanium dioxide precursor solution is titanium tetrachloride, the solvent is ethanol, and the concentration of titanium tetrachloride is 20wt%.

[0085] S100 includes:

[0086] Dissolve phosphomolybdic acid in ethanol to obtain solution A;

[0087] Solution B is obtained by dissolving tin tetrachloride in ethanol;

[0088] Under heating conditions, solution B was added to the titanium dioxide precursor solution in one go, and then 25 wt% solution A was added every 5 minutes. During this period, the system was in an ultrasonic environment. After 20 minutes, the system was allowed to stand at room temperature for 10 hours to obtain a gel. The ultrasonic frequency was 25 kHz.

[0089] S200. The gel is calcined to obtain a preproduct. The calcination temperature is 450℃ and the calcination time is 1.5h. The preproduct is coated with a film to obtain titanium dioxide filler. The coating process includes: mixing and reacting 3 parts by weight of triethanolamine, 3 parts by weight of triisostearoyl titanate isopropyl ester, 90 parts by weight of the preproduct and 100 parts by weight of deionized water, followed by separation, washing with water and drying to obtain titanium dioxide filler. The reaction temperature is 80℃ and the reaction time is 1.5h.

[0090] Comparative Example 1: The difference from Example 7 is that the doped ion solution does not contain Sn. 4+ .

[0091] Comparative Example 2: The difference from Example 7 is that the doped ion solution does not contain Mo. 6+ .

[0092] Comparative Example 3: The difference from Example 7 is that the amount of triethanolamine used is 0.5 parts.

[0093] Comparative Example 4: The difference from Example 7 is that the reaction time of the coating process is 3 hours.

[0094] Comparative Example 5: The difference from Example 7 is that there is no ultrasonic environment.

[0095] Comparative Example 6: The difference from Example 7 is that there was no standing for 10 hours.

[0096] Comparative Example 7: The difference from Example 7 is that no coupling agent is used.

[0097] Experiment 2: Titanium dioxide fillers prepared according to the methods provided in Examples 4-7 and Comparative Examples 1-7 were used to prepare experimental samples. The dielectric constant of the prepared samples was then tested according to GB / T5594.4-2015 standard. The test conditions were: 1MHz, 25℃, and 5mm thickness. The average value was taken after 5 tests for each group. The test results are shown in Table 2.

[0098] Table 2

[0099] Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Dielectric constant 24.3 31.7 32.9 34.1 20.5 26.3 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Dielectric constant 30.6 31.4 32.8 32.7 28.3

[0100] As can be seen from the comparison of the data of Example 5 and Example 4 in Table 2, the addition of the coating process can effectively promote the improvement of the dielectric constant of ceramics by titanium dioxide filler.

[0101] As can be seen from the results of Examples 5-7, the titanium dioxide produced using the process parameters provided in Example 7 has the best performance.

[0102] As can be seen from the comparison between Comparative Examples 1-2 and Example 7, the use of Sn 4+ and Mo 6+ Blending can improve the applicability of titanium dioxide filler in the ceramic sintering process.

[0103] As can be seen from the comparison between Comparative Examples 3-4 and Example 7, the selection of coating raw materials and coating process parameters both affect the degree to which titanium dioxide filler improves the dielectric constant of ceramics.

[0104] As can be seen from the comparison between Comparative Examples 5-6 and Example 7, the ultrasonic environment and the settling process in the titanium dioxide doping process both affect the degree to which titanium dioxide filler improves the dielectric constant of ceramics.

[0105] A comparison of Comparative Example 7 and Example 7 shows that the use of coupling agents can promote the improvement of the dielectric constant of ceramics by titanium dioxide fillers. One reason the applicant hypothesizes is that triethanolamine has low thermal stability, the coating breaks down early, and its restriction on titanium dioxide expansion is weak.

[0106] Experiment 3: The titanium dioxide fillers prepared according to the preparation methods provided in Examples 1-7 and Comparative Examples 1-7 were used to prepare experimental samples. The mechanical properties of the prepared samples were then tested. The average value was taken after 5 tests for each group. The test results are shown in Table 3.

[0107] Example 1 Example 2 Example 3 Example 4 Example 5 flexural strength 304.75 312.48 318.06 339.1 367.89 fracture toughness 4.72 4.78 4.81 5.07 5.43 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 flexural strength 370.04 378.13 319.72 332.08 341.37 fracture toughness 5.56 5.72 4.86 5.11 5.24 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 flexural strength 339.72 350.64 361.27 336.83 fracture toughness 5.20 5.38 5.43 5.17

[0108] Flexural strength is measured in MPa, and fracture toughness in MPa·m. 1 / 2 .

[0109] As can be seen from the test results of Examples 1-7 in Table 1, the ceramic samples prepared using the titanium dioxide filler provided by the present invention all have good mechanical properties.

[0110] As can be seen from the comparison between Comparative Examples 1-7 and Example 7, the specific steps and process parameters of the doping and coating processes all affect the mechanical properties of the ceramic samples prepared using the titanium dioxide filler provided by the present invention.

[0111] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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 producing a titanium white filler for improving the dielectric properties of ceramics, characterized in that, The application relates to a preparation method of a titanium white filler. S100, adding a doping ion solution into a titanium dioxide precursor solution under heating conditions to obtain a gel; The doped ion solution comprises: Mo 6+ and Sn 4+ ; the molar ratio of Mo 6+ to Ti 4+ is (10-30):(1-2), and the molar ratio of Sn 4+ to Ti 4+ is (10-20):(2-3); S200, preparing the titanium white filler through a calcination process.

2. The production method according to claim 1, characterized by, The titanium dioxide precursor solution comprises one or more of tetrabutyl titanate solution, titanyl sulfate solution, tetraisopropyl titanate solution and titanium tetrachloride solution.

3. The preparation method according to claim 1, characterized in that, The temperature of the reaction system in the S100 is 60-80 DEG C, and the pH value is 7.5-9.

4. The production method according to any one of claims 1 to 3, characterized by, The S200 comprises: A100, obtaining a pre-product through the calcination process of the gel; A200, obtaining the titanium white filler through a coating process after coating a film layer on the pre-product; the volatilization temperature or the decomposition temperature of the film layer is 300-600 DEG C.

5. The preparation method according to claim 4, characterized in that, The coating process comprises the following steps: mixing 1-4 parts of triethanolamine, 1.5-5 parts of a coupling agent and 80-100 parts of the pre-product, and then drying to obtain the titanium white filler.

6. The preparation method according to claim 5, characterized in that, The reaction temperature of the coating process is 65-85 DEG C, and the reaction time is 0.8-2 hours.

7. The preparation method according to claim 5, characterized in that, The coupling agent comprises one or more of triisostearyl isopropyl titanate, KH560 and KH570.

8. The preparation method according to claim 4, characterized in that, The S100 comprises: Dissolving phosphomolybdic acid in ethanol to obtain solution A; Dissolving tin tetrachloride in ethanol to obtain solution B; Under heating conditions, solution A and solution B are added into the titanium dioxide precursor solution, and then mixed under ultrasonic environment for 10-30 minutes, and then placed at normal temperature for 8-12 hours to obtain the gel; the ultrasonic frequency is 20-30 KHz.

9. The preparation method according to claim 8, characterized in that, Solution B is added into the titanium dioxide precursor solution at one time, and then solution A is gradually added.

10. The titanium white filler prepared by the preparation method in any one of claims 1-9.