CN113563064A

CN113563064A - Titanium dioxide-based giant dielectric ceramic material and preparation method thereof

Info

Publication number: CN113563064A
Application number: CN202110805670.0A
Authority: CN
Inventors: 胡章贵; 樊江涛; 贺刚; 龙震; 郭帅; 陈以蒙
Original assignee: Tianjin University of Technology
Current assignee: Tianjin University of Technology
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2021-10-29

Abstract

The invention discloses a method for preparing a titanium dioxide-based giant dielectric ceramic material by adopting a solid-phase sintering method, wherein the general formula of the titanium dioxide-based giant dielectric ceramic material is (Tm)_0.5Nb_0.5)_x(Ti_y1‑B_y)_1‑xO₂(x=0~0.1,y=0-0.1), wherein B represents Zr, Sn, Hf or Ge. The invention is a solid-phase sintering method, the method is simple, the repeatability is good, the yield is high, the frequency stability of the obtained titanium dioxide-based giant dielectric ceramic material in the range of 20Hz to 1MHz is good, and the dielectric constant is 10⁴~10⁵And its insulation resistivity is 10⁸~10¹³Omega cm. In addition, the temperature stability is excellent at-150 ℃ to 260 ℃. Has practical application value in various electronic devices such as capacitors and dynamic memories.

Description

Titanium dioxide-based giant dielectric ceramic material and preparation method thereof

Technical Field

The invention belongs to the technical field of electronic ceramics and manufacturing thereof, and particularly relates to a titanium dioxide-based giant dielectric ceramic material and a preparation method thereof.

Background

With the demand of the micro-electronics market for the miniaturization, integration and intellectualization of Ceramic Capacitors and microwave dielectric components, the giant dielectric material with low dielectric loss and high temperature stability is expected to be used in the research and application of Multi-layer Ceramic Capacitors (MLCC). To meet the application requirements of MLCC, a giant dielectric ceramic with low dielectric loss and good temperature/frequency stability is developed (>10³) Becomes an important research direction in the field of materials.

Over the past decade, it has been discovered that inclusion of CaCu₃Ti₄O₁₂、 Ba(Fe_0.5M_0.5)O₃（M＝Nb, Ta, Sb) Li-doped NiO、 RFe₂O₄(R ═ Lu, Er) and La_2-xSr_xNiO₄(x =1/3 and 1/8), and the like, and although the discovery of these new materials has greatly promoted experimental research and related theoretical development of giant dielectric materials, the comprehensive dielectric properties of these systems do not meet the requirements of practical applications (y. Wang, w. Jie, c. Yang, et al. adv. funct. mater., 29(27):1808118, 2019). High dielectric loss is always accompanied by high dielectric constant, and this phenomenon greatly limits the development of electronic material industry. Therefore, achieving the combined dielectric properties of high dielectric constant, low loss, high temperature and wide frequency stability at the same time is an extremely challenging study.

Liu Yun et al discovered TiO in 2013₂The GMR ceramic material has a large dielectric constant and a small dielectric loss (. epsilon.)>10⁴, tanδ<0.05) and has good temperature stabilityAnd frequency stability (W. Hu, Y. Liu, R.L. Withers, et al. nat. mater, 12(9): 821-. Researchers have used different acceptor elements (Al, In, Ga, Al, Co, Cr, Sc, Fe) and donor elements (Nb) to prepare a series of TiO₂A giant dielectric ceramic. Despite the complex defect structure formed by co-doping of different donor and acceptor, so that these TiO compounds₂The base ceramics all have a high dielectric constant (. epsilon.)_r> 10⁴) However, obtaining co-doped ceramics with lower loss, high insulation resistance and excellent temperature stability is an important issue worthy of attention of researchers (CN 110803923 a, CN 105906340 a, CN 105732020 a). Selection of codoped acceptor and donor ions, and ceramic preparation process for TiO₂The promotion of giant dielectric property plays a determining role. For example: the nano ceramic powder with more uniformly dispersed doping elements can be obtained by adopting a wet chemical method. Spark plasma sintering of TiO₂Ceramics have a uniform and dense microstructure (T. NaHaithong, P. Thongbai, S. Maeniri, et al. J. Eur. Ceram. Soc.,37: 655-168660, 2017), (H. Han, P. Dufour, S. Mhin, et al. Phys. chem. Phys., 17:16864-16875, 2015). In addition, the giant dielectric property is improved in relation to the defect structure formed by doping of acceptor and donor ions. The defect structure is related to the ionic size, charge and electronegativity of the dopant.

Therefore, it is desirable to provide a novel co-doped TiO₂The giant dielectric material has the performances of high dielectric constant, low dielectric loss, high insulation resistivity, good temperature and frequency stability and the like.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a TiO with huge dielectric constant, low dielectric loss, high insulation resistivity and excellent temperature stability₂A method for preparing a giant dielectric ceramic material.

In order to solve the above technical problems, according to one aspect of the present invention, there is provided a titania-based giant dielectric ceramic material having a composition represented by the formula (Tm)_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01-0.1, y =0-0.1), wherein B represents Zr, Sn, Hf or Ge.

Further, the titanium dioxide-based giant dielectric ceramic material has a composition expression of (Tm)_0.5Nb_0.5)_x(Ti_1- _yB_y)_1-xO₂ (x=0.01-0.1, y = 0.01-0.1)。

Further, the titanium dioxide-based giant dielectric ceramic material has a composition expression of (Tm)_0.5Nb_0.5)_x(Ti_1- _yB_y)_1-xO₂ (x=0.01-0.06, y = 0.01-0.06)。

Furthermore, the titanium dioxide-based giant dielectric ceramic material has a rutile phase and a compact microstructure, and the size of the crystal grain ranges from 3 μm to 20 μm.

According to another aspect of the present invention, there is provided a method for preparing the titania-based giant dielectric ceramic material, comprising:

step one, ball-milling and mixing the raw materials with zirconia balls and absolute ethyl alcohol, and then drying to obtain primary titanium dioxide-based ceramic powder; the starting material is Tm₂O₃、Nb₂O₅And TiO₂And ZrO₂、SnO₂、HfO₂Or GeO₂；

Step two, presintering titanium dioxide-based ceramic powder to obtain presintering powder, grinding the presintering powder in a mortar for 30min to obtain secondary titanium dioxide-based ceramic powder, weighing 0.5g of the secondary titanium dioxide-based ceramic powder, adding 8% by mass of polyvinyl alcohol aqueous solution, granulating, sieving, and pressing in a powder tablet press under the pressure of 100MPa to prepare sample pieces; and then placing the crucible in a muffle furnace, heating the crucible to 550 ℃ at the speed of 1 ℃/min, preserving heat for 2h, removing the glue, laying a layer of mother powder with the same components and the thickness of 1mm on a crucible cover of alumina to reduce the pollution of the alumina crucible under high-temperature sintering as much as possible, placing a sample piece after removing the glue on the crucible cover, covering the sample piece with the mother powder with the same components, turning the crucible upside down, covering and sealing the crucible, immediately placing the crucible in the muffle furnace, heating the crucible to 1400 ℃ at the speed of 2 ℃/min, preserving heat for 5h, and naturally cooling the crucible to room temperature to obtain the compact crystalline ceramics.

And step three, polishing the flat surface of the titanium dioxide-based ceramic obtained in the step two on a polishing machine, respectively coating silver paste on the upper surface and the lower surface of the titanium dioxide-based ceramic, drying, and then placing the titanium dioxide-based ceramic in a resistance furnace for silver burning for 0.5 hour at 800-850 ℃ to obtain the titanium dioxide-based ceramic material.

Further, in the step one, the mass ratio of the raw materials to the zirconia balls to the absolute ethyl alcohol is 1:3: 2.

Further, in the second step, the titanium dioxide-based ceramic powder is presintered at 1000-1100 ℃ for 2-6 hours to obtain presintered powder.

Further, in the second step, a polyvinyl alcohol aqueous solution is added into the secondary titanium dioxide-based ceramic powder, and the mixture is granulated and sieved by a 80-mesh sieve.

Further, in the third step, after silver pastes are respectively coated on the upper surface and the lower surface of the titanium dioxide-based ceramic, the titanium dioxide-based ceramic is dried at 120 ℃.

The giant dielectric TiO provided by the invention₂The ceramic material is rutile phase, has a compact microstructure, and has a grain size of 3-20 mm. Giant dielectric TiO₂The ceramic material has large dielectric constant (10000-90000) at 1kHz, low dielectric loss (0.004-0.09) and large insulation resistivity (10)⁸-10¹³Omega cm) and exhibits excellent temperature and frequency stability in the range of-150-260 ℃ and 20Hz-1 MHz. And, in the case of doping ZrO₂、SnO₂、HfO₂And GeO₂Then, the insulation resistivity of the giant dielectric ceramic is obviously improved.

In addition, the invention adopts a solid-phase sintering method, and has the advantages of simple method, good repeatability and high yield. The used raw materials are all oxides, the price is low, the yield is high, and the preparation method is suitable for large-scale industrial production. Has great practical value in the times of miniaturization and light weight of electronic elements. Especially, the device prepared by the ceramic has practical application value in various electronic devices such as capacitors and the like.

Drawings

FIG. 1 is (Tm)_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0~0.1,y = 0) X-ray diffraction pattern of the ceramic sample of the system.

FIG. 2 is (Tm)_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0~0.1,y = 0) microscopic structure of ceramic sample.

FIG. 3 is (Tm)_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0~0.1,y = 0) dielectric frequency spectrum of the ceramic sample.

FIG. 4 is (Tm)_0.5Nb_0.5)_0.01Ti_0.99O₂Temperature coefficients of ceramic samples at different frequencies.

Detailed Description

Example 1

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01, y = 0) treatment of raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.01Ti_0.99O₂Stoichiometric weighing of Tm processed in step (1)₂O₃(99.999%)2.3435g、TiO₂(99.99%)96.0421g、Nb₂O₅(99.99%)1.6144g of raw material powder;

(3) ball milling and mixing: adding the weighed raw materials into a ball milling tank, taking zirconia balls as milling balls and absolute ethyl alcohol as a ball milling medium, fully milling for 24 hours, separating the zirconia balls, putting the raw material mixture into a drying oven, and drying at 75 ℃ to obtain the (Tm)_0.5Nb_0.5)_0.01Ti_0.99O₂Ceramic powder;

(4) (Tm_0.5Nb_0.5)_0.01Ti_0.99O₂synthesis of the complex: the crucible was placed in a muffle furnace at 2 ℃/minRaising the temperature to 1100 deg.c, maintaining for 6 hr and cooling naturally to 150 deg.c. Taking out the pre-synthesized powder, and grinding in a mortar for 30min to obtain giant dielectric ceramic powder;

(5) granulating, tabletting and discharging rubber: weighing 0.5g of the powder obtained in the step (4), adding 8% by mass of polyvinyl alcohol binder, uniformly mixing, sieving with a 80-mesh sieve, and pressing into sample tablets in a powder tablet press under the pressure of 100 MPa; then heating to 550 ℃ at the speed of 1 ℃/min in a muffle furnace, and preserving heat for 2h for removing glue;

(6) and (3) sintering: and (3) placing the obtained sample piece on a crucible cover of alumina, paving a layer of mother powder with the thickness of 1mm and the same components to reduce the pollution of the alumina crucible under high-temperature sintering as much as possible, placing the sample piece obtained in the step (5) on the sample piece, covering the sample piece with the mother powder with the same components, inverting the crucible, covering and sealing the crucible, immediately placing the sample piece in a muffle furnace, heating to 1400 ℃ at the speed of 3 ℃/min, preserving the temperature for 15h, and naturally cooling to room temperature along with the furnace body to obtain the compact crystalline ceramics.

(7) Silver burning: polishing the surface of the sintered titanium dioxide-based ceramic on a polishing machine, respectively coating silver paste on the upper surface and the lower surface of the sintered titanium dioxide-based ceramic, drying, and then placing the ceramic in a resistance furnace to burn silver for 0.5 hour at 850 ℃ to obtain the giant dielectric and low-loss titanium dioxide-based giant dielectric ceramic material.

Referring to FIG. 1 and Table 1, FIG. 1(a) shows the X-ray diffraction pattern obtained for the composition of example 1, from which it can be seen that the crystalline phase of the sample is TiO₂。

Referring to FIG. 2 and Table 1, FIG. 2(a) is a scanning electron micrograph of the ceramic sample obtained in example 1, and it can be observed that the ceramic sample has a dense structure and an average grain size of 5.43 mm.

Referring to fig. 3 and table 1, where x =0.01 in fig. 3 is the dielectric properties of the ceramic sample obtained in example 1, it can be seen that the ceramic sample has a large dielectric constant (21741) and a low dielectric loss (0.006) at a frequency of 1 kHz.

Referring to FIG. 4 and Table 1, FIG. 4 is a graph showing the temperature coefficient of the ceramic sample obtained in example 1 at different frequencies from-150 ℃ to 300 ℃. It can be concluded from the figure that the sample has excellent temperature stability in the range of-150 ℃ to 260 ℃ at a frequency of 1kHz, and is suitable for XR9 series capacitors.

Example 2

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.02, y = 0) treatment of raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.02Ti_0.98O₂Stoichiometric weighing of Tm processed in step (1)₂O₃9(9.999%) 4.5511g、TiO₂(99.99%)92.3138g、Nb₂O₅(99.99%)3.1351g of raw material powder;

(3) ball milling and mixing: adding the weighed raw materials into a ball milling tank, taking zirconia balls as milling balls and absolute ethyl alcohol as a ball milling medium, fully milling for 24 hours, separating the zirconia balls, putting the raw material mixture into a drying oven, and drying at 75 ℃ to obtain the (Tm)_0.5Nb_0.5)_0.02Ti_0.98O₂Ceramic powder;

(4) (Tm_0.5Nb_0.5)_0.02Ti_0.98O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1100 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in a mortar for 30min to obtain giant dielectric ceramic powder;

(5) granulating, tabletting and discharging rubber: weighing 0.5g of the powder obtained in the step (4), adding 8% by mass of polyvinyl alcohol binder, uniformly mixing, sieving with a 80-mesh sieve, and pressing into sample tablets in a powder tablet press under the pressure of 100 MPa; then placing the mixture in a muffle furnace, heating the mixture to 550 ℃ at a speed of 1 ℃/min, and preserving the heat for 2h to remove the glue;

(6) and (3) sintering: and (3) placing the obtained sample piece on a crucible cover of alumina, paving a layer of mother powder with the thickness of 1mm and the same components to reduce the pollution of the alumina crucible under high-temperature sintering as much as possible, placing the sample piece obtained in the step (5) on the sample piece, covering the sample piece with the mother powder with the same components, inverting the crucible, covering and sealing the crucible, immediately placing the sample piece in a muffle furnace, heating to 1400 ℃ at the speed of 2 ℃/min, preserving the temperature for 5h, and naturally cooling to room temperature along with the furnace body to obtain the compact crystalline ceramics.

Referring to FIG. 1 and Table 1, FIG. 1(b) shows the X-ray diffraction pattern obtained for the composition of example 2, from which it can be seen that the crystalline phase of the sample is TiO₂。

Referring to FIG. 2 and Table 1, FIG. 2(b) is a scanning electron micrograph of the ceramic sample obtained in example 2, and it can be observed that the ceramic sample has a dense structure and an average grain size of 5.84 mm.

Referring to fig. 3 and table 1, x =0.02 in fig. 3 is the dielectric properties of the ceramic sample obtained in example 2, and it can be seen that the ceramic sample has a large dielectric constant (35202) and a low dielectric loss (0.034) at a frequency of 1 kHz.

Example 3:

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.04, y = 0) treatment of raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.04Ti_0.96O₂Stoichiometric weighing of Tm processed in step (1)₂O₃(99.999%) 8.6031g、TiO₂(99.99%)85.4706g、Nb₂O₅(99.99%)5.9263g of raw material powder;

(3) ball milling and mixing: adding the weighed raw materials into a ball milling tank, taking zirconia balls as milling balls and absolute ethyl alcohol as a ball milling medium, fully milling for 24 hours, separating the zirconia balls, putting the raw material mixture into a drying oven, and drying at 75 ℃ to obtain the (Tm)_0.5Nb_0.5)_0.04Ti_0.96O₂Ceramic powder;

(4) (Tm_0.5Nb_0.5)_0.04Ti_0.96O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1100 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in a mortar for 30min to obtain giant dielectric ceramic powder;

(7) Silver burning: polishing the surface of the sintered titanium dioxide-based ceramic on a polishing machine, respectively coating silver paste on the upper surface and the lower surface of the sintered titanium dioxide-based ceramic, drying, and then placing the ceramic in a resistance furnace to burn silver for 0.5 hour at 800 ℃ to obtain the giant dielectric and low-loss titanium dioxide-based giant dielectric ceramic material.

Referring to FIG. 1 and Table 1, FIG. 1(c) shows the X-ray diffraction pattern obtained from the composition of example 3, from which it can be seen that the crystalline phase of the sample is TiO₂。

Referring to FIG. 2 and Table 1, FIG. 2(c) is a scanning electron micrograph of the ceramic sample obtained in example 3, and it can be observed that the ceramic sample has a dense structure and an average grain size of 11.74 mm.

Referring to fig. 3 and table 1, x =0.04 in fig. 3 is the dielectric properties of the ceramic sample obtained in example 3, and it can be seen that the ceramic sample has a large dielectric constant (42699) and a low dielectric loss (0.039) at a frequency of 1 kHz.

Example 4:

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.06, y = 0) treatment of raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.06Ti_0.94O₂Stoichiometric weighing of Tm processed in step (1)₂O₃(99.999%)12.2337g、TiO₂(99.99%)79.3390g、Nb₂O₅(99.99%)8.4273g of raw material powder;

(3) ball milling and mixing: adding the weighed raw materials into a ball milling tank, taking zirconia balls as milling balls and absolute ethyl alcohol as a ball milling medium, wherein the mass ratio of a raw material mixture to the zirconia balls to the absolute ethyl alcohol is 1:3:2, fully milling for 24 hours, separating the zirconia balls, and drying the raw material mixture in a drying oven at 75 ℃ to obtain giant dielectric ceramic powder;

(4) (Tm_0.5Nb_0.5)_0.06Ti_0.94O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1100 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in mortar for 30min to obtain (Tm)_0.5Nb_0.5)_0.06Ti_0.94O₂Ceramic powder;

Referring to FIG. 1 and Table 1, FIG. 1(d) is an X-ray diffraction pattern obtained by carrying out 4 components, from which it can be seen that the main crystal phase of the sample is TiO₂And Tm is present₂Ti₂O₇A second phase.

Referring to FIG. 2 and Table 1, FIG. 2(d) is a scanning electron micrograph of the ceramic sample obtained in example 4, which shows a dense structure and an average grain size of 7.63 mm.

Referring to fig. 3 and table 1, x =0.06 in fig. 3 is the dielectric properties of the ceramic sample obtained in example 4, and it can be seen that the ceramic sample has a large dielectric constant (30677) and a low dielectric loss (0.041) at a frequency of 1 kHz.

Example 5:

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01, y = 0.01) wherein B is ZrO₂And (3) treating raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Zirconium oxide (ZrO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.01(Ti_0.99Zr_0.01)_0.99O₂Stoichiometric weighing of Tm processed in step (1)₂O₃(99.999%) 2.3090g、TiO₂(99.99%)94.6257g、Nb₂O₅(99.99%)1.5906g、ZrO₂(99.99%)27.4401g of raw material powder;

(4) (Tm_0.5Nb_0.5)_0.01(Ti_0.99Zr_0.01)_0.99O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1100 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in a mortar for 30min to obtain giant dielectric ceramic powder;

Referring to Table 1, for example 5, the giant dielectric ceramic grain size was 6.52 μm, the ceramic sample had a larger dielectric constant (21315) and a low dielectric loss (0.032) and the insulation resistivity was 6.23X 10 at a frequency of 1kHz¹²Ωcm。

Example 6:

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01, y = 0.04) wherein B is ZrO₂And (3) treating raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide(Nb₂O₅) Titanium oxide (TiO)₂) Zirconium oxide (ZrO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.01(Ti_0.96Zr_0.04)_0.99O₂Stoichiometric weighing of Tm processed in step (1)₂O₃(99.999%) 2.2952g、TiO₂(99.99%)90.2602g、Nb₂O₅(99.99%)1.5811g、ZrO₂(99.99%)60.2022g of raw material powder;

(4) (Tm_0.5Nb_0.5)_0.01(Ti_0.96Zr_0.04)_0.99O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1100 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in a mortar for 30min to obtain giant dielectric ceramic powder;

Referring to Table 1, for example 6, the giant dielectric ceramic has a grain size of 8.11 μm, the ceramic sample has a large dielectric constant (21257) and a low dielectric loss (0.040) and the insulation resistivity is 8.05X 10 at a frequency of 1kHz¹¹Ωcm。

Example 7:

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01, y = 0.06) wherein B is ZrO₂And (3) treating raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Zirconium oxide (ZrO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.01(Ti_0.94Zr_0.06)_0.99O₂Stoichiometric weighing of Tm processed in step (1)₂O₃(99.999%)2.2718g、TiO₂(99.99%)87.4578g、Nb₂O₅(99.99%)1.5649g、ZrO₂(99.99%)69.4099g of raw material powder;

(4) (Tm_0.5Nb_0.5)_0.01(Ti_0.94Zr_0.06)_0.99O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1100 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in a mortar for 30min to obtain giant dielectric ceramic powder;

Referring to Table 1, for example 7, the giant dielectric ceramic had a grain size of 7.33 μm, the ceramic sample had a large dielectric constant (46214) and a low dielectric loss (0.042) and the insulation resistivity was 5.13X 10 at a frequency of 1kHz¹²Ωcm。

Example 8:

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01, y = 0.01) wherein B is SnO₂And (3) treating raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Zirconium oxide (SnO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.01(Ti_0.99Sn_0.01)_0.99O₂Stoichiometric weighing of Tm processed in step (1)₂O₃(99.999%)2.3235g、TiO₂(99.99%)94.2608g、Nb₂O₅(99.99%)1.6006g、SnO₂(99.99%)31.6252g of raw material powder;

(4) (Tm_0.5Nb_0.5)_0.01(Ti_0.99Sn_0.01)_0.99O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1070 ℃ at the speed of 5 ℃/min, the temperature is preserved for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in a mortar for 30min to obtain giant dielectric ceramic powder;

Referring to Table 1, for example 8, the macropolydielectric ceramic grain size was 6.41 μm, the ceramic sample had a large dielectric constant (52357) and a low dielectric loss (0.030) and the insulation resistivity was 9.41X 10 at a frequency of 1kHz¹¹Ωcm。

Example 9:

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01, y = 0.01) wherein B is HfO₂And (3) treating raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Zirconium oxide (HfO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.01(Ti_0.99Hf_0.01)_0.99O₂Stoichiometric weighing of (Tm) processed in step (1)₂O₃99.999%)2.3069g、(TiO₂99.99%)93.5870g、(Nb₂O₅99.99%)1.5892g、(HfO₂99.99%)39.2464g of raw material powder;

(4) (Tm_0.5Nb_0.5)_0.01(Ti_0.99Hf_0.01)_0.99O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1050 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in a mortar for 30min to obtain giant dielectric ceramic powder;

Referring to Table 1, for example 9, the giant dielectric ceramic has a grain size of 7.36 μm, the ceramic sample has a large dielectric constant (65201) and a low dielectric loss (0.020) and an insulation resistivity of 5.06X 10 at a frequency of 1kHz¹¹Ωcm。

Example 10:

(1) (Tm_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01, y = 0.01) wherein B is GeO₂And (3) treating raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Zirconium oxide (GeO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.01(Ti_0.99Ge_0.01)_0.99O₂Stoichiometric weighing of Tm processed in step (1)₂O₃(99.999%)2.3365g、TiO₂(99.99%)94.7867g、Nb₂O₅(99.99%)1.6095g、GeO₂24.3076g of raw material powder (9.99%);

(4) (Tm_0.5Nb_0.5)_0.01(Ti_0.99Ge_0.01)_0.99O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1000 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in a mortar for 30minObtaining giant dielectric ceramic powder;

(7) Silver burning: polishing the surface of the sintered titanium dioxide-based ceramic on a polishing machine, respectively coating silver paste on the upper surface and the lower surface of the sintered titanium dioxide-based ceramic, drying, and then placing the ceramic in a resistance furnace to burn silver for 0.5 hour at 810 ℃ to obtain the giant dielectric and low-loss titanium dioxide-based giant dielectric ceramic material.

Referring to Table 1, for example 10, the giant dielectric ceramic had a grain size of 9.42 μm, the ceramic sample had a large dielectric constant (81035) and a low dielectric loss (0.04) and an insulation resistivity of 9.71X 10 at a frequency of 1kHz¹⁰Ωcm。

Comparative example 1:

(1) (Tm_0.5Nb_0.5)_0.10Ti_0.90O₂treatment of raw material powder: thulium oxide (Tm)₂O₃) Niobium oxide (Nb)₂O₅) Titanium oxide (TiO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: according to (Tm)_0.5Nb_0.5)_0.10Ti_0.90O₂Stoichiometric weighing of Tm processed in step (1)₂O₃(99.999%)18.4690g、TiO₂(99.99%)68.8083g、Nb₂O₅(99.99%)12.7227g of raw material powder;

(3) ball milling and mixing: adding the weighed raw materials into a ball milling tank, taking zirconia balls as grinding balls and anhydrous ethylTaking alcohol as a ball milling medium, fully ball milling the raw material mixture for 24 hours with the mass ratio of zirconia balls to absolute ethyl alcohol being 1:3:2, separating the zirconia balls, putting the raw material mixture into a drying oven, and drying at 75 ℃ to obtain (Tm)_0.5Nb_0.5)_0.10Ti_0.90O₂Ceramic powder;

(4) (Tm_0.5Nb_0.5)_0.10Ti_0.90O₂synthesis of the complex: the crucible is put into a muffle furnace, the temperature is raised to 1100 ℃ at the speed of 5 ℃/min, the temperature is kept for 2h, and the crucible is naturally cooled to about 150 ℃ along with the furnace body. Taking out the pre-synthesized powder, and grinding in mortar for 30min to obtain (Tm)_0.5Nb_0.5)_0.10Ti_0.90O₂Ceramic powder;

Referring to Table 1, for comparative example 1, due to excessively high content of the component impurity phase, the grain size was reduced to 3.11 μm, resulting in a decrease in dielectric constant to 10114 and an increase in dielectric loss property to 0.049, and the insulation resistivity was 5.55X 10⁸Ωcm。

Comparative example 2:

(1) TiO₂treatment of raw material powder: oxygen gasTitanium (TiO)₂) Drying at 150 deg.C for 5 hr;

(2) weighing and batching: weigh 100g (TiO)₂99.99%) of raw material powder;

(3) granulating, tabletting and discharging rubber: weighing 0.5g of the powder obtained in the step (2), adding 8% by mass of polyvinyl alcohol binder, uniformly mixing, sieving with a 80-mesh sieve, and pressing into sample tablets in a powder tablet press under the pressure of 100 MPa; then placing the mixture in a muffle furnace, heating the mixture to 550 ℃ at a speed of 1 ℃/min, and preserving the heat for 2h to remove the glue;

(4) and (3) sintering: and (3) placing the obtained sample piece on a crucible cover of alumina, paving a layer of mother powder with the same component and the thickness of 1mm to reduce the pollution of the alumina crucible under high-temperature sintering as much as possible, placing the sample piece obtained in the step (3) on the sample piece, covering the sample piece with the mother powder with the same component, inverting the crucible, covering and sealing the crucible, immediately placing the sample piece in a muffle furnace, heating to 1400 ℃, preserving heat for 5h, and naturally cooling to room temperature along with the furnace body to obtain the compact crystalline ceramics.

(7) Silver burning: polishing the surface of the sintered titanium dioxide ceramic on a polishing machine, respectively coating silver paste on the upper surface and the lower surface of the sintered titanium dioxide ceramic, drying, and then placing the ceramic in a resistance furnace to burn silver for 0.5 hour at 850 ℃ to obtain the titanium dioxide ceramic material.

Referring to Table 1, for comparative example 2, pure TiO₂The ceramic had a crystal grain size of 5 μm, a dielectric constant of 800, a dielectric loss of 0.34, and an insulation resistivity of 9.25X 10¹²Ωcm。。

Table 1 summarizes the average particle size, dielectric constant, dielectric loss and insulation resistivity of examples 1 to 10 and comparative examples 1 to 2 as follows:

TABLE 1 grain size and dielectric Properties at Room temperature for samples of different compositions

And (4) conclusion: co-doped TiO₂The giant dielectric ceramic has a large dielectric constant (>10⁴) And extremely low dielectric loss (<0.05) having an insulation resistivity of 10⁸-10¹³Omega cm. And, atDoped ZrO₂、SnO₂、HfO₂And GeO₂And then, the jump distance of local electrons among the defect clusters is increased, so that the insulation resistivity of the giant dielectric ceramic is obviously improved. The invention has practical application value in various electronic devices such as capacitors, dynamic memories and the like.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications belonging to the technical solutions of the present invention are within the scope of the present invention.

Claims

1. A titanium dioxide-based giant dielectric ceramic material is characterized in that: the expression of the component is (Tm)_0.5Nb_0.5)_x(Ti_1- _yB_y)_1-xO₂ (x=0.01-0.1, y =0-0.1), wherein B represents Zr, Sn, Hf or Ge.

2. The titania-based giant dielectric ceramic material of claim 1, wherein: the component expression is (Tm)_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01-0.1, y = 0.01-0.1)。

3. The titania-based gigadielectric ceramic material of claim 2, wherein: the component expression is (Tm)_0.5Nb_0.5)_x(Ti_y1-B_y)_1-xO₂ (x=0.01-0.06, y = 0.01-0.06)。

4. The titania-based giant dielectric ceramic material of claims 1-3, wherein: the titanium dioxide-based giant dielectric ceramic material has a rutile phase and a compact microstructure, and the size range of grains is 3-20 mu m.

5. The method of preparing the titanium dioxide-based gigadielectric ceramic material of any one of claims 1-4, comprising:

Step two, presintering titanium dioxide-based ceramic powder to obtain presintering powder, grinding the presintering powder in a mortar for 30min to obtain secondary titanium dioxide-based ceramic powder, weighing 0.5g of the secondary titanium dioxide-based ceramic powder, adding 8% by mass of polyvinyl alcohol aqueous solution, granulating, sieving, and pressing in a powder tablet press under the pressure of 100MPa to prepare sample pieces; spreading a layer of mother powder with the same component and the thickness of 1mm on a crucible cover of alumina to reduce the pollution of the alumina crucible under high-temperature sintering as much as possible, placing a sample piece after the glue removal on the crucible cover, covering the sample piece with the mother powder with the same component, inverting the crucible to cover and seal the crucible, immediately placing the crucible in the muffle furnace, heating the crucible to 1400 ℃ at the speed of 2 ℃/min, preserving the heat for 5h, and naturally cooling the crucible to room temperature along with the furnace body to obtain compact crystalline ceramics;

6. The method of preparing a titania-based giant dielectric ceramic material according to claim 5, wherein: in the first step, the mass ratio of the raw materials to the zirconia balls and the absolute ethyl alcohol is 1:3: 2.

7. The method of preparing a titania-based giant dielectric ceramic material according to claim 5, wherein: in the second step, the titanium dioxide-based ceramic powder is presintered at 1000-1100 ℃ for 2-6 hours to obtain presintered powder.

8. The method of preparing a titania-based giant dielectric ceramic material according to claim 5 or 6, wherein: and in the second step, adding a polyvinyl alcohol aqueous solution into the secondary titanium dioxide-based ceramic powder, granulating, and sieving by a 80-mesh sieve.

9. The method of preparing a titania-based giant dielectric ceramic material according to claim 7, wherein: and in the third step, silver pastes are respectively coated on the upper surface and the lower surface of the titanium dioxide-based ceramic, and then the titanium dioxide-based ceramic is dried at 120 ℃.