A bimetallic element doped CCTO modified dielectric ceramic material and a preparation method thereof

Abstract

This invention discloses a bimetallic element-doped CCTO-modified dielectric ceramic material and its preparation method, belonging to the technical field of dielectric functional ceramic materials. The chemical formula of the bimetallic element-doped CCTO-modified dielectric ceramic material is CaCu. 3‑ x Zn x Ti 3.95 Zr 0.05 O 12 ; among which, 0

Description

Technical Field

[0001] This invention relates to the field of dielectric functional ceramic materials technology, and in particular to a bimetallic element-doped CCTO modified dielectric ceramic material and its preparation method. Background Technology

[0002] CCTO's high dielectric constant stems from its unique perovskite structure, which enables the material to exhibit a polarization effect under an applied electric field. However, CCTO suffers from drawbacks such as high dielectric loss, strong process sensitivity, and poor frequency stability of its dielectric properties, which severely restricts the practical application of CCTO ceramics. Research shows that the dielectric properties of CCTO materials are closely related to their microstructure, and doping with trace amounts of metal elements can effectively regulate its crystal structure and electrical properties. Patent CN115321976B discloses a CCTO ceramic material with a high dielectric constant and low dielectric loss, as well as its preparation method. By co-doping with Nd and Nb, the material's low-frequency dielectric loss is reduced while maintaining a high dielectric constant, overcoming the shortcomings of traditional methods that reduce the dielectric constant when using highly insulating ceramics. However, its optimal sintering temperature is 1100℃, and the dielectric loss is as low as 0.02. The dielectric loss varies significantly with frequency over a wide frequency range, making it difficult to maintain stable dielectric properties. Furthermore, the higher sintering temperature leads to increased energy consumption. Summary of the Invention

[0003] The purpose of this invention is to provide a bimetallic element-doped CCTO modified dielectric ceramic material and its preparation method, which effectively reduces dielectric loss, maintains a high dielectric constant, improves the frequency dependence of CCTO, and maintains efficient and stable dielectric performance over a wide frequency range.

[0004] To achieve the above objectives, this invention provides a bimetallic element-doped CCTO-modified dielectric ceramic material, the chemical formula of which is CaCu. 3-x Zn x Ti 3.95 Zr 0.05 O 12 ; among which, 0 <x<3。

[0005] This invention provides a method for preparing a bimetallic element-doped CCTO modified dielectric ceramic material, comprising the following steps:

[0006] S1. Mix calcium nitrate tetrahydrate, copper nitrate trihydrate, tetrabutyl titanate, zinc nitrate hexahydrate and zirconium oxynitrate with solvents respectively, cover with plastic wrap and stir to obtain solutions A, B, C, D and E.

[0007] S2. Mix solutions A, B, C, D and E to obtain a precursor solution;

[0008] S3. The pH of the precursor solution was adjusted using concentrated nitric acid, and CCTO colloid was obtained after stirring and aging.

[0009] S4. Dry the CCTO colloid in a vacuum oven to obtain a dry gel, and then put the dry gel into a ball mill and grind it into powder.

[0010] S5. The ball-milled powder is placed in a muffle furnace for sintering, and then cooled to room temperature to obtain powder F;

[0011] S6. Mix powder F with PVA adhesive evenly, and compress the mixture using a tablet press to obtain a smooth round tablet.

[0012] S7. Anneal the wafers in a muffle furnace and cool to room temperature to obtain CaCu. 3-x Zn x Ti 3.95 Zr 0.05 O 12 Ceramic materials.

[0013] Preferably, in S1, the solvent is one of deionized water and anhydrous ethanol;

[0014] The solvent for both solutions A and D is deionized water;

[0015] The solvents for solutions B, C, and D are all anhydrous ethanol.

[0016] Preferably, in S1, the stirring time is 10-30 min.

[0017] Preferably, in S2, the molar ratio of Ca, Cu, Zn, Ti, and Zr in the precursor solution is 1:(2.9-2.975):(0.025-0.1):3.95:0.05.

[0018] Preferably, in S3, the concentration of concentrated nitric acid is 60-70%, the pH of the precursor solution is adjusted to 1-2, the stirring time is 1-3 hours, and the aging time is 36-72 hours.

[0019] Preferably, in step S4, the drying temperature is 80-100℃ and the drying time is 48-96h.

[0020] Preferably, in S5, the specific sintering operation is as follows: the temperature is increased from room temperature to 350-400℃ at a heating rate of 5-10℃ / min, held for 3-4 hours, and then increased to 900-950℃ and held for 10-12 hours.

[0021] Preferably, in S6, the concentration of PVA adhesive is 3-7%.

[0022] Preferably, in S7, the specific operation of the annealing treatment is as follows: first, heat to 300-350℃ and hold for 1-2 hours, then heat to 700-750℃ and hold for 1-2 hours, and finally heat to 900-1000℃ and hold for 4-6 hours.

[0023] Therefore, the present invention employs the above-mentioned bimetallic element-doped CCTO modified dielectric ceramic material and its preparation method, which has the following beneficial effects:

[0024] (1) Zn and Zr-doped CCTO ceramic materials were prepared by the sol-gel method. This method is not constrained by the solid-state reaction mechanism, allowing a precise number of doped ions to enter the CCTO lattice and replace the corresponding ion sites at a relatively low sintering temperature. This resulted in the preparation of CaCu with uniform mixing, high density, and strong mechanical properties. 3-x Zn x Ti 3.95 Zr 0.05 O 12 Ceramic materials;

[0025] (2) Zn- and Zr-doped CCTO ceramic materials were prepared using the sol-gel method, by controlling the Zn content. 2+ The microstructure of CCTO can be controlled by adjusting the doping ratio and annealing temperature, which can effectively improve the dielectric constant of the material and reduce the dependence of dielectric properties on frequency.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0027] Figure 1 These are XRD patterns of the ceramic materials in Examples 1-4 of the present invention: a bimetallic element-doped CCTO modified dielectric ceramic material and its preparation method.

[0028] Figure 2 This invention relates to a bimetallic element-doped CCTO modified dielectric ceramic material and its preparation method. Examples 1-4 show the dielectric constant of the ceramic material prepared at an annealing temperature of 900℃ as a function of frequency.

[0029] Figure 3 This is a graph showing the dielectric constant of a bimetallic element-doped CCTO modified dielectric ceramic material and its preparation method, prepared in Examples 5-8 of this invention, with an annealing temperature of 1000℃, as a function of frequency.

[0030] Figure 4 This is a graph showing the dielectric loss of a bimetallic element-doped CCTO modified dielectric ceramic material and its preparation method, prepared in Examples 1-4 of this invention, with an annealing temperature of 900℃, as a function of frequency.

[0031] Figure 5 This is a graph showing the dielectric loss of a bimetallic element-doped CCTO modified dielectric ceramic material and its preparation method, prepared in Examples 1-4 of this invention, with an annealing temperature of 1000℃, as a function of frequency. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0034] Example 1

[0035] A bimetallic element-doped CCTO modified dielectric ceramic material, the preparation method of which includes the following steps:

[0036] S1. Add calcium nitrate tetrahydrate to deionized water, cover with plastic wrap, and stir on a magnetic stirrer for 20 minutes to obtain a colorless and transparent solution A; add copper nitrate trihydrate to anhydrous ethanol, cover with plastic wrap, and stir on a magnetic stirrer for 20 minutes to obtain a blue and transparent solution B; add tetrabutyl titanate to anhydrous ethanol, cover with plastic wrap, and stir on a magnetic stirrer for 20 minutes to obtain a pale yellow solution C; add zinc nitrate hexahydrate to deionized water, cover with plastic wrap, and stir on a magnetic stirrer for 20 minutes to obtain a colorless and transparent solution D; add zirconium oxynitrate to anhydrous ethanol, cover with plastic wrap, and stir on a magnetic stirrer for 20 minutes to obtain a colorless and transparent solution E.

[0037] S2. Pour solution A into solution C under continuous stirring. Wash the beaker containing solution A three times with glacial acetic acid. Pour all the washing liquid into the mixture of solution A and solution C. Repeat the above operation for solutions B, D and E. Finally, mix to obtain the precursor solution. The molar ratio of Ca, Cu, Zn, Ti and Zr in the precursor solution is 1:2.975:0.025:3.95:0.05.

[0038] S3. Adjust the pH of the precursor solution to 1.37 using 65% concentrated nitric acid, cover with plastic wrap to prevent evaporation. After magnetic stirring for 2 hours, a light blue solution is obtained. After aging at room temperature for 72 hours, a light blue jelly-like CCTO colloid is obtained.

[0039] S4. The CCTO colloid was dried in a vacuum oven at 80°C for 96 hours to obtain a blue-green dry gel. The dry gel was then ball-milled into a blue-green powder.

[0040] S5. The ball-milled powder was placed in an alumina crucible that had been washed and dried with anhydrous ethanol and sintered in a muffle furnace. The temperature was first increased from room temperature to 350°C at a rate of 5°C / min and held for 3 hours. Then the temperature was increased to 900°C and held for 10 hours. After cooling to room temperature, brown powder F was obtained.

[0041] S6. Mix powder F with 5% PVA binder evenly, and compress the mixture into tablets using a tablet press at a pressure of 10 MPa to obtain dark brown, smooth round tablets.

[0042] S7. Anneal the wafers in a muffle furnace. First, raise the temperature to 300℃ and hold for 1 hour, then raise it to 700℃ and hold for 1 hour, and finally raise it to 900℃ and hold for 6 hours. After cooling to room temperature, CaCu annealed at 900℃ is obtained. 2.975 Zn 0.025 Ti 3.95 Zr 0.05 O 12 Ceramic materials.

[0043] Example 2

[0044] Example 2 differs from Example 1 in that the molar ratio of Ca, Cu, Zn, Ti, and Zr in the precursor solution in Example 2 is 1:2.95:0.05:3.95:0.05, resulting in CaCu alloy with an annealing temperature of 900℃. 2.95 Zn 0.05 Ti 3.95 Zr 0.05 O 12 Ceramic materials.

[0045] Example 3

[0046] Example 3 differs from Example 1 in that the molar ratio of Ca, Cu, Zn, Ti, and Zr in the precursor solution in Example 3 is 1:2.925:0.075:3.95:0.05, resulting in CaCu alloy with an annealing temperature of 900℃. 2.925 Zn 0.075 Ti 3.95 Zr 0.05 O 12 Ceramic materials.

[0047] Example 4

[0048] Example 4 differs from Example 1 in that the molar ratio of Ca, Cu, Zn, Ti, and Zr in the precursor solution in Example 4 is 1:2.9:0.1:3.95:0.05, resulting in CaCu alloy with an annealing temperature of 900℃. 2.9 Zn 0.1 Ti 3.95 Zr 0.05 O 12Ceramic materials.

[0049] Example 5

[0050] Example 5 differs from Example 1 in that the specific step S7 in Example 5 is as follows: The wafer is annealed in a muffle furnace, first heated to 300°C and held for 1 hour, then heated to 700°C and held for 1 hour, and finally heated to 1000°C and held for 6 hours. After cooling to room temperature, CaCu with an annealing temperature of 1000°C is obtained. 2.975 Zn 0.025 Ti 3.95 Zr 0.05 O 12 Ceramic materials.

[0051] Example 6

[0052] The difference between Example 6 and Example 2 is that the specific steps in S7 of Example 6 are as follows: the wafer is annealed in a muffle furnace, first heated to 300°C and held for 1 hour, then heated to 700°C and held for 1 hour, and finally heated to 1000°C and held for 6 hours. After cooling to room temperature, CaCu with an annealing temperature of 1000°C is obtained. 2.95 Zn 0.05 Ti 3.95 Zr 0.05 O 12 Ceramic materials.

[0053] Example 7

[0054] Example 7 differs from Example 3 in that the specific steps of S7 in Example 7 are as follows: The wafer is annealed in a muffle furnace, first heated to 300°C and held for 1 hour, then heated to 700°C and held for 1 hour, and finally heated to 1000°C and held for 6 hours. After cooling to room temperature, CaCu annealed at 1000°C is obtained. 2.925 Zn 0.075 Ti 3.95 Zr 0.05 O 12 Ceramic materials.

[0055] Example 8

[0056] The difference between Example 8 and Example 4 is that the specific steps in S7 of Example 8 are as follows: the wafer is annealed in a muffle furnace, first heated to 300°C and held for 1 hour, then heated to 700°C and held for 1 hour, and finally heated to 1000°C and held for 6 hours. After cooling to room temperature, CaCu with an annealing temperature of 1000°C is obtained. 2.9 Zn 0.1 Ti 3.95 Zr 0.05 O 12 Ceramic materials.

[0057] Test 1

[0058] The ceramic materials prepared in Examples 1-4 with an annealing temperature of 900℃ were subjected to XRD testing, and the results are as follows: Figure 1 As shown. From Figure 1 It can be seen from this that different Zn 2+ The doped ceramic samples all exhibited strong peaks at the (220), (400), and (422) crystal planes, corresponding to the strong peaks on the CCTO standard card, and different Zn values... 2+ The characteristic peaks of the doping amount are shifted compared to the standard spectrum, indicating that changing the doping amount of metal elements will affect the crystal microstructure.

[0059] Test 2

[0060] The ceramic materials prepared in Examples 1-8 were ground and polished, conductive silver paste was applied to both electrodes of the ceramic materials, and wires were welded to both ends before electrical performance testing was performed.

[0061] Figure 2 The graphs show the dielectric constant of the ceramic materials prepared in Examples 1-4 at an annealing temperature of 900℃ as a function of frequency. Figure 3 This is a graph showing the dielectric constant as a function of frequency for the ceramic materials prepared in Examples 5-8 at an annealing temperature of 1000℃. Figure 2 and Figure 3 As can be seen, the dielectric constant decreases with increasing frequency. When the annealing temperature increases from 900℃ to 1000℃, the dielectric constant decreases significantly. Furthermore, at the same annealing temperature, the dielectric constant increases with increasing Zn... 2+ As the doping concentration increases, the dielectric constant tends to decrease, but the ceramic material still exhibits giant dielectric properties.

[0062] Figure 4 The graphs show the dielectric loss as a function of frequency for the ceramic materials prepared in Examples 1-4 at an annealing temperature of 900℃. Figure 5 This is a graph showing the dielectric loss as a function of frequency for the ceramic materials prepared in Examples 5-8 at an annealing temperature of 1000℃. Figure 4 and Figure 5 As can be seen, the dielectric loss first decreases and then increases with increasing frequency, and different Zn... 2+ The dielectric loss of ceramic materials treated with different doping amounts and annealing temperatures varies significantly. Annealing temperature 1000℃, Zn... 2+ CaCu with doping level x = 0.1 2.9 Zn 0.1 Ti 3.95 Zr 0.05 O 12The ceramic material has a minimum dielectric loss D = 0.002 at 100Hz and a dielectric constant K = 1270. In addition, its dielectric loss is small and stable over a wide frequency range, always maintaining a low level, and the frequency dependence of dielectric loss is well regulated.

[0063] Therefore, the present invention employs the above-mentioned bimetallic element-doped CCTO modified dielectric ceramic material and its preparation method to effectively reduce dielectric loss, maintain a high dielectric constant, improve the frequency dependence of CCTO, and maintain efficient and stable dielectric performance over a wide frequency range.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a bimetallic element-doped CCTO modified dielectric ceramic material, characterized in that, The preparation method includes the following steps: S1. Mix calcium nitrate tetrahydrate, copper nitrate trihydrate, tetrabutyl titanate, zinc nitrate hexahydrate and zirconium oxynitrate with solvents respectively, cover with plastic wrap and stir to obtain solutions A, B, C, D and E. S2. Mix solutions A, B, C, D and E to obtain a precursor solution; S3. The pH of the precursor solution was adjusted using concentrated nitric acid, and CCTO colloid was obtained after stirring and aging. S4. Dry the CCTO colloid in a vacuum oven to obtain a dry gel, and then put the dry gel into a ball mill and grind it into powder. S5. The ball-milled powder is placed in a muffle furnace for sintering, and then cooled to room temperature to obtain powder F; S6. Mix powder F with PVA adhesive evenly, and compress the mixture using a tablet press to obtain a smooth round tablet. S7. Anneal the wafers in a muffle furnace and cool to room temperature to obtain CaCu. 2.9 Zn 0.1 Ti 3.95 Zr 0.05 O 12 Ceramic materials; The specific steps for annealing are as follows: first, raise the temperature to 300-350℃ and hold for 1-2 hours, then raise the temperature to 700-750℃ and hold for 1-2 hours, and finally raise the temperature to 1000℃ and hold for 4-6 hours.

2. The preparation method according to claim 1, characterized in that, In S1, the solvent is either deionized water or anhydrous ethanol. The solvent for both solutions A and D is deionized water; The solvents for solutions B, C, and D are all anhydrous ethanol.

3. The preparation method according to claim 1, characterized in that, In S1, the stirring time is 10-30 minutes.

4. The preparation method according to claim 1, characterized in that, In S3, the concentration of concentrated nitric acid is 60-70%, the pH of the precursor solution is adjusted to 1-2, the stirring time is 1-3 hours, and the aging time is 36-72 hours.

5. The preparation method according to claim 1, characterized in that, In S4, the drying temperature is 80-100℃ and the drying time is 48-96h.

6. The preparation method according to claim 1, characterized in that, In S5, the specific sintering operation is as follows: the temperature is increased from room temperature to 350-400℃ at a heating rate of 5-10℃ / min, held for 3-4 hours, and then increased to 900-950℃ and held for 10-12 hours.

7. The preparation method according to claim 1, characterized in that, In S6, the concentration of PVA adhesive is 3-7%.

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