Modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate and preparation method thereof

Abstract

The application provides a modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate and a preparation method thereof, and the preparation method comprises the following steps: drying treatment is performed on raw materials to obtain the raw materials; the raw materials are placed in a zirconium oxide ball mill tank, zirconium oxide grinding balls are added in proportion for dry grinding to obtain mixed powder; the mixed powder is pre-sintered to form a perovskite precursor phase, and then naturally cooled to room temperature to obtain pre-sintered powder; the pre-sintered powder is wet ball milled with anhydrous ethanol to obtain slurry, the slurry is dried, and then sieved to obtain powder; the powder is uniformly mixed with a polyvinyl alcohol binder and then cold isostatic pressing is performed to obtain a round sheet; the round sheet is sequentially subjected to first-stage and second-stage treatments in a high-temperature furnace, and then cooled to room temperature with the furnace to obtain a sample. The application obtains a mixed oxide ceramic with good crystallinity, strong composition uniformity and high phase purity through sintering, the obtained ceramic has improved density, is not prone to decomposition, and has enhanced mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dielectric functional ceramic material preparation, and particularly relates to a modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate and a preparation method thereof. BACKGROUND

[0002] From the miniaturized chip components to the high-performance energy storage devices, the dielectric materials with high dielectric constant, low dielectric loss and excellent stability have become the key elements to promote the miniaturization, integration and high performance of electronic devices. Under this background, calcium copper titanate (CCTO for short) as a new type of dielectric material with great potential has attracted much attention due to its unique physical properties. However, although CCTO has many advantages mentioned above, it still faces some limitations in practical application. When the working frequency enters the medium-high frequency region (especially the critical frequency band), the dielectric loss of CCTO will increase significantly. The increase of dielectric loss not only leads to energy waste and reduces the working efficiency of electronic devices, but also may cause device heating, affecting the stability and reliability of the device, and thus limiting the application of CCTO in electronic circuits such as audio circuits, part of communication circuits and other electronic circuits with strict requirements for low dielectric loss in the frequency band.

[0003] However, although CCTO has many advantages mentioned above, it still faces some limitations in practical application. When the working frequency enters the medium-high frequency region (especially the critical frequency band), the dielectric loss of CCTO will increase significantly. The increase of dielectric loss not only leads to energy waste and reduces the working efficiency of electronic devices, but also may cause device heating, affecting the stability and reliability of the device, and thus limiting the application of CCTO in electronic circuits such as audio circuits, part of communication circuits and other electronic circuits with strict requirements for low dielectric loss in the frequency band. SUMMARY

[0004] In view of the above situation, the main purpose of the present application is to provide a modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate and a preparation method thereof to solve the above technical problems.

[0005] The present application provides a preparation method of a modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate, which comprises the following steps:

[0006] S1, drying treatment is performed on calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide to obtain raw materials after drying treatment, and the raw materials after drying treatment are cooled to room temperature in a dryer to obtain raw materials;

[0007] S2, the raw materials are placed in a zirconium oxide ball mill jar, zirconium oxide grinding balls are added in proportion, the ball mill jar is sealed and filled with nitrogen, and dry grinding is performed in a planetary ball mill in the form of forward and reverse rotation alternation to obtain a mixed powder;

[0008] S3, the mixed powder is lightly pressed and densified, then placed in a corundum crucible and put into a muffle furnace for pre-sintering to form a perovskite precursor phase, and after natural cooling to room temperature, the agglomerates are broken by grinding to obtain a pre-sintered powder;

[0009] ​S4, the pre-sintered powder is added to anhydrous ethanol for wet ball milling to obtain a slurry, a titanate coupling agent is added to the slurry and stirring is carried out at a certain temperature to obtain a treated slurry, the treated slurry is subjected to ultrasonic dispersion treatment and then dried in an oven, and sieving is carried out to obtain an intermediate powder;

[0010] S5, the polyvinyl alcohol adhesive is uniformly mixed with the intermediate powder, and then aging and cold isostatic pressing are carried out to obtain a round sheet;

[0011] S6, the round sheet is placed in a pulsed magnetic field for gradient magnetic field assisted pre-sintering treatment to obtain a gradient magnetic field treated round sheet;

[0012] S7, the gradient magnetic field treated round sheet is placed on an alumina pad and placed in a high-temperature furnace for first stage treatment to obtain a first stage sintered product, the first stage sintered product is subjected to second stage annealing treatment to obtain a second stage product, and the second stage product is cooled to room temperature in the furnace to obtain a ceramic sample, wherein, .

[0013] Compared with the prior art, the present application has the following advantages:

[0014] 1. The present application can easily prepare a uniform mixed oxide ceramic by sintering to obtain nanoparticles with good crystallinity, strong uniformity of composition and high phase purity, so that the obtained ceramic has improved density, is not easy to decompose and has enhanced mechanical properties.

[0015] 2. The present application can coordinate the microstructure and electrical properties of CCTO by co-doping elements to realize the dielectric ceramic material required at a specific frequency.

[0016] Additional aspects and advantages of the present application will be given in part in the following description, will become apparent from the following description, or will be understood by those skilled in the art through embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The dielectric constant and dielectric loss change curve schematic diagram of the modified dielectric ceramic material sample prepared for example 1, example 2, example 3 and example 4;

[0018] Figure 2 The dielectric constant and dielectric loss change curve schematic diagram of the modified dielectric ceramic material sample prepared for example 5, example 6, example 7 and example 8. DETAILED DESCRIPTION

[0019] Embodiments of the present application are described below in the detailed description and illustrated in the accompanying drawings by which like or similar elements, symbols and / or numerals are meant to indicate like or similar elements, symbols and / or numerals among the several views. The embodiments described below are merely exemplary and are not intended to limit the application of the embodiments of the present application.

[0020] These and other aspects of embodiments of the present application will become apparent from the following description and the accompanying drawings. In the description and drawings, particular embodiments of the embodiments of the present application are disclosed in connection with specific details to present embodiments of the application, one or more features of which are specifically illustrated in the drawings. It will be appreciated that the scope of the embodiments of the present application is not limited to these specific embodiments.

[0021] Embodiment 1

[0022] The present embodiment provides a preparation method of a modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate, which comprises the following steps:

[0023] S1, drying treatment of calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide at 100°C for 3h to obtain dried raw materials, and cooling the dried raw materials to room temperature in a desiccator to obtain raw materials;

[0024] S2, placing the raw materials in a zirconia ball mill jar, adding zirconia grinding balls at a ball-to-material ratio of 8:1, sealing the ball mill jar, filling nitrogen, and dry grinding in a planetary ball mill at a speed of 250rpm in a forward and reverse alternating manner for 6h to obtain a mixed powder;

[0025] S3, lightly pressing and densifying the mixed powder, placing it in a corundum crucible, and placing it in a muffle furnace to heat at a rate of 4°C / min to 800°C for 4h for pre-sintering to form a perovskite precursor phase, and after natural cooling to room temperature, grinding and crushing the agglomerates to obtain a pre-sintered powder;

[0026] S4, adding the pre-sintered powder to anhydrous ethanol at a solid-to-liquid ratio of 1:2 for wet ball milling at a speed of 200rpm for 4h to obtain a slurry, adding 0.75%wt of a titanate coupling agent to the slurry and stirring at a constant temperature of 60°C for 2h to obtain a treated slurry, ultrasonic dispersion treatment of the treated slurry, and drying treatment of the slurry in an oven at 70°C for 12h, and then passing through a 180 mesh sieve to obtain an intermediate powder;

[0027] S5, mixing 5wt% polyvinyl alcohol binder with the intermediate powder, aging, and then cold isostatic pressing at 150MPa to form a φ10mmx1mm disc;

[0028] S6, the wafer is placed in a 1.5T pulse magnetic field, and the temperature is raised to 600°C at a temperature raising rate of 5°C / min and kept for 1h, and gradient magnetic field assisted pre-sintering treatment is carried out to obtain a wafer after gradient magnetic field treatment, wherein the included angle between the magnetic field direction and the axial direction of the wafer is 45°;

[0029] S7, the wafer after gradient magnetic field treatment is placed on an alumina pad and put into a high-temperature furnace, and the temperature is raised to 1100°C at a temperature raising rate of 5°C / min and kept for 1h for first stage sintering treatment to obtain a first stage sintering product, the first stage sintering product is cooled to 950°C at a cooling rate of 1°C / min and kept for 8h for second stage annealing treatment to obtain a second stage product, and the second stage product is cooled to room temperature in the furnace to obtain a ceramic sample.

[0030] Example 2

[0031] The embodiment provides a preparation method of a modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate, and the method comprises the following steps:

[0032] S1, the calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide are subjected to drying treatment at 120°C for 4h to obtain raw materials after drying treatment, and the raw materials after drying treatment are cooled to room temperature in a dryer to obtain raw materials;

[0033] S2, the raw materials are placed in a zirconium oxide ball mill jar, zirconium oxide grinding balls are added at a ball-to-material ratio of 10:1, the ball mill jar is sealed and filled with nitrogen, and dry grinding is carried out in a planetary ball mill at a speed of 300rpm in a forward-reverse alternating mode for 8h to obtain a mixed powder;

[0034] S3, the mixed powder is lightly pressed and densified, then placed in a corundum crucible and put into a muffle furnace to be heated to 850°C at a temperature raising rate of 5°C / min and kept for 6h for pre-sintering to form a perovskite precursor phase, and the perovskite precursor phase is naturally cooled to room temperature, then crushed by grinding to obtain a pre-sintered powder;

[0035] S4, the pre-sintered powder is added to anhydrous ethanol at a solid-to-liquid ratio of 1:3, wet ball milling is carried out at a speed of 250rpm for 6h to obtain a slurry, 0.75%wt of a titanate coupling agent is added to the slurry and stirred at a constant temperature of 60°C for 2h to obtain a treated slurry, the treated slurry is subjected to ultrasonic dispersion treatment, and the slurry is subjected to drying treatment in an oven at 80°C for 24h, and then the slurry is sieved through a 200-mesh sieve to obtain an intermediate powder;

[0036] S5, 6%wt of polyvinyl alcohol adhesive is uniformly mixed with the intermediate powder, and then cold isostatic pressing is performed at 200MPa after aging to obtain a wafer with a diameter of 10mm and a thickness of 1mm;

[0037] S6, place the wafer in a 1.5T strength pulsed magnetic field, and increase the temperature to 600 DEG C at a rate of 5 DEG C / min and keep for 1h, and perform gradient magnetic field assisted pre-burning treatment to obtain a wafer after gradient magnetic field treatment, wherein the angle between the magnetic field direction and the wafer axial direction is 45 DEG ;

[0038] S7, place the wafer after gradient magnetic field treatment on an alumina pad, and put it into a high-temperature furnace, and increase the temperature to 1100 DEG C at a rate of 8 DEG C / min and keep for 2h to perform first-stage sintering treatment, to obtain a first-stage sintering product, and perform second-stage annealing treatment on the first-stage sintering product at a rate of 2 DEG C / min to cool to 950 DEG C and keep for 10h, to obtain a second-stage product, and then cool to room temperature with the furnace, to obtain a ceramic sample.

[0039] Example 3

[0040] The embodiment provides a preparation method of a modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate, and the method comprises the following steps:

[0041] S1, dry the calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide at 150 DEG C for 6h to obtain dried raw materials, and cool the dried raw materials to room temperature in a dryer to obtain raw materials;

[0042] S2, place the raw materials in a zirconia ball mill jar, add zirconia grinding balls at a ball-to-material ratio of 12:1, seal the ball mill jar, fill nitrogen, and dry grind in a planetary ball mill at a speed of 300 rpm in a forward and reverse alternating mode for 10h to obtain a mixed powder;

[0043] S3, lightly press the mixed powder to compactness, then place it in a corundum crucible, and put it into a muffle furnace to increase the temperature to 900 DEG C at a rate of 6 DEG C / min and keep for 8h to perform pre-burning, to form a perovskite precursor phase, and then naturally cool to room temperature, and break the agglomerates by grinding to obtain a pre-burning powder;

[0044] S4, add the pre-burning powder to anhydrous ethanol at a solid-to-liquid ratio of 1:4, and perform wet ball milling at a speed of 300 rpm for 8h to obtain a slurry, add 0.75%wt of a titanate coupling agent to the slurry, and stir at a constant temperature of 60 DEG C for 2h to obtain a treated slurry, perform ultrasonic dispersion treatment on the treated slurry, and then dry the slurry in an oven at 90 DEG C for 36h, and then pass through a 220-mesh sieve to obtain an intermediate powder;

[0045] S5, mix 7%wt of polyvinyl alcohol binder with the intermediate powder, and then cold isostatic press form at 250MPa after aging to obtain a wafer with a diameter of 10 mm and a thickness of 1 mm;

[0046] S6. Place the disc in a pulsed magnetic field with an intensity of 1.5T, raise the temperature to 600℃ at a heating rate of 5℃ / min and hold for 1h, and perform gradient magnetic field assisted pre-burning treatment to obtain a disc after gradient magnetic field treatment, wherein the angle between the magnetic field direction and the disc axis is 45°.

[0047] S7. Place the gradient magnetic field treated discs on an alumina pad and put them into a high-temperature furnace. Heat the furnace to 1100℃ at a rate of 10℃ / min and hold for 3 hours for the first stage of sintering, obtaining the first-stage sintered product. Then, perform a second-stage annealing treatment on the first-stage sintered product, cooling it to 950℃ at a rate of 2℃ / min and holding for 12 hours to obtain the second-stage product. Finally, cool the product to room temperature in the furnace to obtain the final product. Ceramic sample.

[0048] Example 4

[0049] This embodiment provides a method for preparing a modified dielectric ceramic material based on niobium-zirconium bimetallic element doping of calcium copper titanate, the method comprising the following steps:

[0050] S1. Calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide are dried at 120°C for 4 hours to obtain the dried raw materials. The dried raw materials are then placed in a desiccator and cooled to room temperature to obtain the raw materials.

[0051] S2. Place the raw material in a zirconia ball mill jar, add zirconia grinding balls at a ball-to-material ratio of 10:1, seal the ball mill jar and fill it with nitrogen. Dry grind the raw material in a planetary ball mill at a speed of 300 rpm for 8 hours using alternating forward and reverse rotation to obtain a mixed powder.

[0052] S3. After the mixed powder is lightly pressed to be dense, it is placed in a corundum crucible and put into a muffle furnace to be heated to 850°C at 5°C / min and held for 6 hours for pre-calcination to form a perovskite precursor phase. After naturally cooling to room temperature, the agglomerates are broken up by grinding to obtain pre-calcined powder.

[0053] S4. Add anhydrous ethanol to the pre-calcined powder at a solid-liquid ratio of 1:3 and wet ball mill at 250 rpm for 6 hours to obtain a slurry. Add 0.75% wt of titanate coupling agent to the slurry and stir at a constant temperature of 60℃ for 2 hours to obtain the treated slurry. After ultrasonic dispersion, the treated slurry is dried in an oven at 80℃ for 24 hours and then passed through a 200-mesh sieve to obtain intermediate powder.

[0054] S5. Mix 6wt% polyvinyl alcohol binder with intermediate powder evenly, age it, and then cold isostatically press it at 200MPa to obtain a disc with a diameter of φ10 mm × 1 mm.

[0055] S6, the wafer is placed in a 1.5T pulse magnetic field, and the temperature is raised to 600 DEG C at a temperature rising rate of 5 DEG C / min and kept for 1h, and gradient magnetic field assisted pre-sintering treatment is carried out to obtain the wafer after gradient magnetic field treatment, wherein the included angle between the magnetic field direction and the wafer axial direction is 45 DEG ;

[0056] S7, the wafer after gradient magnetic field treatment is placed on an alumina pad plate, and is put into a high-temperature furnace, and is heated to 1100 DEG C at a temperature rising rate of 8 DEG C / min and kept for 2h to carry out first stage sintering treatment, to obtain a first stage sintering product, the first stage sintering product is cooled to 950 DEG C at a temperature falling rate of 2 DEG C / min and kept for 10h to carry out second stage annealing treatment, to obtain a second stage product, and then the furnace is cooled to room temperature, to obtain a ceramic sample.

[0057] Example 5

[0058] The embodiment provides a preparation method of modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate, and the method comprises the following steps:

[0059] S1, the calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide are subjected to drying treatment at 120 DEG C for 4h to obtain raw materials after drying treatment, and the raw materials after drying treatment are cooled to room temperature in a dryer to obtain raw materials;

[0060] S2, the raw materials are placed in a zirconium oxide ball mill jar, zirconium oxide grinding balls are added according to a ball-to-material ratio of 10:1, the ball mill jar is sealed and filled with nitrogen, and dry grinding is carried out in a planetary ball mill at a rotating speed of 300 rpm in a forward-reverse alternating mode for 8h to obtain mixed powder;

[0061] S3, the mixed powder is lightly pressed and densified, then is placed in a corundum crucible and is put into a muffle furnace to be heated to 850 DEG C at a temperature rising rate of 5 DEG C / min and kept for 6h to carry out pre-sintering, a perovskite precursor phase is formed, and after natural cooling to room temperature, the agglomerates are broken by grinding to obtain pre-sintered powder;

[0062] S4, the pre-sintered powder is added into anhydrous ethanol at a solid-liquid ratio of 1:3, wet ball milling is carried out at a rotating speed of 250 rpm for 6h to obtain slurry, 0.75%wt of titanate coupling agent is added into the slurry, and stirring is carried out at a constant temperature of 60 DEG C for 2h to obtain treated slurry, the treated slurry is subjected to ultrasonic dispersion treatment, and then the slurry is subjected to drying treatment in an oven at 80 DEG C for 24h, and then the slurry is passed through a 200-mesh sieve to obtain intermediate powder;

[0063] S5, 6%wt of polyvinyl alcohol binder is uniformly mixed with the intermediate powder, and after aging, cold isostatic pressing is carried out at 200MPa to obtain a wafer with a diameter of 10 mm and a thickness of 1 mm;

[0064] S6, the wafer is placed in a 1.5T pulse magnetic field, and the temperature is raised to 600 DEG C at a temperature rising rate of 5 DEG C / min and kept for 1h, and gradient magnetic field assisted pre-sintering treatment is carried out to obtain the wafer after gradient magnetic field treatment, wherein the included angle between the magnetic field direction and the wafer axial direction is 45 DEG ;

[0065] S7, the wafer after gradient magnetic field treatment is placed on an alumina pad plate, and is put into a high-temperature furnace, and is heated to 1100 DEG C at a temperature rising rate of 8 DEG C / min and kept for 2h to carry out first stage sintering treatment, to obtain a first stage sintering product, the first stage sintering product is cooled to 1050 DEG C at a temperature falling rate of 2 DEG C / min and kept for 10h to carry out second stage annealing treatment, to obtain a second stage product, and then the furnace is cooled to room temperature, to obtain a ceramic sample.

[0066] Example 6

[0067] The embodiment provides a preparation method of modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate, and the method comprises the following steps:

[0068] S1, the calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide are subjected to drying treatment at 120 DEG C for 4h to obtain raw materials after drying treatment, and the raw materials after drying treatment are cooled to room temperature in a dryer to obtain raw materials;

[0069] S2, the raw materials are placed in a zirconium oxide ball mill jar, zirconium oxide grinding balls are added at a ball-to-material ratio of 10:1, the ball mill jar is sealed and filled with nitrogen, and dry grinding is carried out in a planetary ball mill at a rotating speed of 300 rpm in a forward-reverse alternating mode for 8h to obtain mixed powder;

[0070] S3, the mixed powder is lightly pressed and densified, then is placed in a corundum crucible and is put into a muffle furnace to be heated to 850 DEG C at a temperature rising rate of 5 DEG C / min and kept for 6h to carry out pre-sintering, a perovskite precursor phase is formed, and after natural cooling to room temperature, the agglomerates are broken by grinding to obtain pre-sintered powder;

[0071] S4, the pre-sintered powder is added into anhydrous ethanol at a solid-liquid ratio of 1:3, wet ball milling is carried out at a rotating speed of 250 rpm for 6h to obtain slurry, 0.75%wt of titanate coupling agent is added into the slurry, and stirring is carried out at a constant temperature of 60 DEG C for 2h to obtain treated slurry, the treated slurry is subjected to ultrasonic dispersion treatment, and then the slurry is subjected to drying treatment in an oven at 80 DEG C for 24h, and then the slurry is passed through a 200-mesh sieve to obtain intermediate powder;

[0072] S5, 6%wt of polyvinyl alcohol adhesive is uniformly mixed with the intermediate powder, and after aging, cold isostatic pressing is carried out at 200MPa to obtain a wafer with a diameter of 10 mm and a thickness of 1 mm;

[0073] S6, the wafer is placed in a 1.5T pulse magnetic field, and the temperature is raised to 600 DEG C at a temperature rising rate of 5 DEG C / min and kept for 1h, and gradient magnetic field assisted pre-sintering treatment is carried out to obtain the wafer after gradient magnetic field treatment, wherein the included angle between the magnetic field direction and the axial direction of the wafer is 45 DEG ;

[0074] S6, the wafer after gradient magnetic field treatment is placed on an alumina pad plate, and is put into a high-temperature furnace, and is heated to 1100 DEG C at a temperature rising rate of 8 DEG C / min and kept for 2h to carry out first stage sintering treatment, to obtain a first stage sintering product, the first stage sintering product is cooled to 1050 DEG C at a cooling rate of 2 DEG C / min and kept for 10h to carry out second stage annealing treatment, to obtain a second stage product, and then the furnace is cooled to room temperature, to obtain a ceramic sample.

[0075] Embodiment 7

[0076] The embodiment provides a preparation method of a modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate, and the method comprises the following steps:

[0077] S1, the calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide are subjected to drying treatment at 100 DEG C for 3h to obtain raw materials after drying treatment, and the raw materials after drying treatment are cooled to room temperature in a dryer to obtain raw materials;

[0078] S2, the raw materials are placed in a zirconium oxide ball mill jar, zirconium oxide grinding balls are added at a ball-to-material ratio of 8:1, nitrogen is filled in the sealed ball mill jar, and dry grinding is carriedously in a planetary ball mill at a rotating speed of 250 rpm in a forward-reverse alternating mode for 6h to obtain mixed powder;

[0079] S3, the mixed powder is lightly pressed and densified, then is placed in a corundum crucible, and is put into a muffle furnace to be heated to 800 DEG C at a temperature rising rate of 4 DEG C / min and kept for 4h to carry out pre-sintering, to form a perovskite precursor phase, and after natural cooling to room temperature, the agglomerates are broken by grinding to obtain pre-sintered powder;

[0080] S4, the pre-sintered powder is added into anhydrous ethanol at a solid-liquid ratio of 1:2, and wet ball milling is carried out at a rotating speed of 200 rpm for 4h to obtain slurry, 0.75%wt of titanate coupling agent is added into the slurry, and stirring is carried out at a constant temperature of 60 DEG C for 2h to obtain treated slurry, the treated slurry is subjected to ultrasonic dispersion treatment, and then the slurry is subjected to drying treatment in an oven at 70 DEG C for 12h, and then the slurry is passed through a 180-mesh sieve to obtain intermediate powder;

[0081] S5, 5%wt of polyvinyl alcohol binder is uniformly mixed with the intermediate powder, and after aging, cold isostatic pressing is carried out at 150 MPa to obtain a wafer with a diameter of 10 mm and a thickness of 1 mm;

[0082] S6, the wafer is placed in a 1.5T pulse magnetic field, and the temperature is raised to 600 DEG C at a temperature rising rate of 5 DEG C / min and kept for 1h, and gradient magnetic field assisted pre-sintering treatment is carried out to obtain the wafer after gradient magnetic field treatment, wherein the included angle between the magnetic field direction and the axial direction of the wafer is 45 DEG ;

[0083] S6, the wafer after gradient magnetic field treatment is placed on an alumina pad plate, and is put into a high-temperature furnace, and is heated to 1100 DEG C at a temperature rising rate of 8 DEG C / min and kept for 2h to carry out first stage sintering treatment, to obtain a first stage sintering product, the first stage sintering product is cooled to 1050 DEG C at a cooling rate of 2 DEG C / min and kept for 10h to carry out second stage annealing treatment, to obtain a second stage product, and then the furnace is cooled to room temperature, to obtain a ceramic sample.

[0084] Example 8

[0085] The embodiment provides a preparation method of modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate, and the method comprises the following steps:

[0086] S1, the calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide are subjected to drying treatment at 150 DEG C for 6h to obtain raw materials after drying treatment, and the raw materials after drying treatment are cooled to room temperature in a dryer to obtain raw materials;

[0087] S2, the raw materials are placed in a zirconium oxide ball mill jar, zirconium oxide grinding balls are added at a ball-to-material ratio of 12:1, nitrogen is filled in the sealed ball mill jar, and dry grinding is carriedously in a planetary ball mill at a rotating speed of 300 rpm in a forward-reverse alternating mode for 10h to obtain mixed powder;

[0088] S3, the mixed powder is lightly pressed and densified, then is placed in a corundum crucible, and is put into a muffle furnace to be heated to 900 DEG C at a temperature rising rate of 6 DEG C / min and kept for 8h to carry out pre-sintering, to form a perovskite precursor phase, and after natural cooling to room temperature, the agglomerates are broken by grinding to obtain pre-sintered powder;

[0089] S4, the pre-sintered powder is added into anhydrous ethanol at a solid-liquid ratio of 1:4, and wet ball milling is carried out at a rotating speed of 300 rpm for 8h to obtain slurry, 0.75%wt of titanate coupling agent is added into the slurry, and stirring is carried out at a constant temperature of 60 DEG C for 2h to obtain treated slurry, the treated slurry is subjected to ultrasonic dispersion treatment, and the slurry is subjected to drying treatment in an oven at 90 DEG C for 36h, and then the slurry is sieved through a 220-mesh sieve to obtain intermediate powder;

[0090] S5, 7%wt of polyvinyl alcohol binder is uniformly mixed with the intermediate powder, and after aging, cold isostatic pressing is carried out at 250 MPa to obtain a wafer with a diameter of 10 mm and a thickness of 1 mm;

[0091] S6, the wafer is placed in a 1.5T pulse magnetic field, the temperature is raised to 600 DEG C at a rate of 5 DEG C / min and kept for 1h, and gradient magnetic field assisted pre-burning treatment is carried out to obtain the wafer after gradient magnetic field treatment, wherein the angle between the magnetic field direction and the axial direction of the wafer is 45 DEG ;

[0092] S6, the wafer after gradient magnetic field treatment is placed on an alumina pad plate, and is put into a high-temperature furnace, and is heated to 1100 DEG C at a rate of 8 DEG C / min and kept for 2h to carry out first-stage sintering treatment, to obtain a first-stage sintering product, the first-stage sintering product is cooled to 1050 DEG C at a rate of 2 DEG C / min and kept for 10h to carry out second-stage annealing treatment, to obtain a second-stage product, and then the furnace is cooled to room temperature to obtain a ceramic sample.

[0093] Example 9

[0094] The application also provides a modified dielectric ceramic material based on niobium-zirconium double metal element doped calcium copper titanate, which is prepared by the preparation method in Example 2.

[0095] The application also studies the dielectric constant and dielectric loss of the modified dielectric ceramic material under different annealing temperature conditions.

[0096] The research of the application shows that: as homologous elements, metal zirconium and titanium are stable when substituted into the site in CCTO ceramic to provide the lowest energy configuration. Appropriate doping into CCTO can effectively reduce the tangent angle tan delta of dielectric loss while maintaining high dielectric constant by inhibiting grain growth. The dielectric ceramic has excellent dielectric properties, and the results show that the doping in CCTO ceramic can refine the grain and improve the uniformity of the grain size. However, in the medium and high frequency range, the dielectric loss still cannot meet the actual demand. Therefore, on the basis of doping , double metal element doping modification is carried out.

[0097] Since the valence of is higher than that of , this high-valence ion substitution will break the original charge balance, and in order to maintain electrical neutrality, the dielectric material will reduce oxygen vacancies and inhibit the reduction of to low-valence With extra electrons, the oxygen vacancy is compensated, that is, the source of carriers (free electrons) is reduced. The moderate introduction of oxygen vacancies can optimize the charge accumulation state at the grain boundary, improve the grain conductivity, stabilize the grain boundary barrier, suppress defect migration, and optimize the microstructure, so that it can maintain a higher dielectric constant in a specific frequency range while suppressing dielectric loss caused by charge disordered migration. In this way, the microstructure of CCTO is regulated to improve its dielectric properties.

[0098] It can be seen from Figures 1 to 2 that the dielectric constant of the modified dielectric ceramic material under different annealing temperature conditions will decrease with the increase of frequency. This is because the change speed of high frequency electric field exceeds the response ability of part of the polarization mechanism in the material, resulting in the reduction of the polarization mechanism involved and the total polarization strength, and finally the dielectric constant decreases. The experimental results show that under the same annealing temperature conditions, the dielectric constant of the ceramic sample after doping will show an overall upward trend with the increase of Nb 5+ doping amount.

[0099] Figure 1 It is shown that after annealing at 950℃, the ceramic sample prepared by Example 4 has a minimum loss tangent angle of 0.073 and a dielectric constant of 367 at

[0100] Figure 2 It is shown that after annealing at 1050℃, the ceramic sample prepared by Example 6 has a minimum loss tangent angle of 0.08 and a dielectric constant of 1616 at

[0101] It should be noted that Figures 1 to 2 the legends in the figures are independent;

[0102] Figure 1 The dielectric constant of all ceramic samples annealed at 950℃ shown in the figure can only reach the order of magnitude in this frequency range, Figure 2 All ceramic samples annealed at 1050℃ shown in the figure can still have a dielectric constant of the order of magnitude while maintaining a low dielectric loss.

[0103] The results show that the dielectric response of calcium copper titanate is significantly improved by doping with niobium and zirconium bimetallic elements. Under the same annealing temperature conditions, appropriate doping can effectively enhance the dielectric response, so that it can maintain a higher dielectric constant in a certain frequency ​​​​The lower layer has good dielectric properties. At the same time, the temperature has a greater impact on it, and different annealing temperatures affect its microstructure and change the dielectric response mechanism. The dielectric properties under the annealing condition of 1050℃ are better. In summary, the ideal demand The ceramic sample is annealed at 1050℃ has a minimum loss tangent angle of 0.08, a dielectric constant of 1616, and a dielectric constant of 40Hz-10 6 Hz dielectric constant is greater than 10 3 order of magnitude.

[0104] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0105] The above-described embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A preparation method of a modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate, characterized in that, The preparation method comprises the following steps: S1, the calcium carbonate, copper oxide, titanium dioxide, niobium pentoxide and zirconium dioxide are subjected to drying treatment to obtain raw materials after drying treatment, and the raw materials after drying treatment are cooled to room temperature in a dryer to obtain raw materials; S2, the raw materials are placed in a zirconium oxide ball mill tank, zirconium oxide grinding balls are added in proportion, the ball mill tank is sealed and filled with nitrogen, dry grinding is carried out in a planetary ball mill in the form of forward and reverse rotation alternation to obtain a mixed powder; S3, the mixed powder is lightly pressed and densified, then placed in a corundum crucible and put into a muffle furnace for pre-sintering to form a perovskite precursor phase, and after natural cooling to room temperature, the agglomerates are broken by grinding to obtain a pre-sintered powder; S4, the pre-sintered powder is added to anhydrous ethanol for wet ball milling to obtain a slurry, a titanate coupling agent is added to the slurry and stirred at a certain temperature to obtain a treated slurry, the treated slurry is subjected to ultrasonic dispersion treatment and then dried in an oven, and sieved to obtain an intermediate powder; S5, the polyvinyl alcohol adhesive is uniformly mixed with the intermediate powder, and after aging, cold isostatic pressing is performed to obtain a round wafer; S6, the round wafer is placed in a pulsed magnetic field for gradient magnetic field assisted pre-sintering treatment to obtain a round wafer after gradient magnetic field treatment; S7, placing the wafer after gradient magnetic field treatment on an alumina pad plate, putting into a high temperature furnace for first stage sintering treatment to obtain a first stage sintering product, cooling the first stage sintering product to a target temperature for second stage annealing treatment, obtaining a second stage product, and cooling to room temperature with the furnace to obtain ceramic samples, wherein ; In S7, the heating rate of the first stage sintering treatment is 5-10℃ / min, the target temperature of the first stage sintering treatment is 1050-1150℃, the holding time of the first stage sintering treatment is 1-3h, the cooling rate of the first stage sintering product is 1-3℃ / min, the target temperature of the second stage annealing treatment is 900-1050℃, and the holding time of the second stage annealing treatment is 8-12h.

2. The method for preparing the modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate according to claim 1, characterized in that, In S1, the drying temperature is 100-150℃, the drying time is 3-6h, the purity of calcium carbonate and titanium dioxide is ≥99.8%, and the purity of copper oxide, niobium pentoxide and zirconium dioxide is ≥99.5%.

3. The method for preparing the modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate according to claim 2, characterized in that, In step S2, the ball-to-material ratio is 8:1-12:1, the ball milling speed is 250-350rpm, and the ball milling time is 6-10h.

4. The method for preparing the modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate according to claim 3, characterized in that, In step S3, the pre-sintering heating rate is 4-6℃ / min, the target temperature of pre-sintering is 800-900℃, and the holding time is 4-8h.

5. The method for preparing the modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate according to claim 4, characterized in that, In step S4, the ball milling speed is 200-300rpm, the ball milling time is 4-8h, the addition amount of the titanate coupling agent is 0.75wt%, the stirring temperature is constant 60℃, the stirring time is 2h, the drying temperature is 70-90℃, the drying time is 12-36h, and the sieving mesh size is 180-220 meshes.

6. The method for preparing the modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate according to claim 5, characterized in that, In step S5, the addition amount of polyvinyl alcohol is 5-7wt%, and the forming pressure is 150-250MPa.

7. The method for preparing the modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate according to claim 6, characterized in that, In step S6, the strength of the pulsed magnetic field is 1.5T, the pre-sintering heating rate is 5℃ / min, the target temperature of the pre-sintering is 600℃, the holding time is 1h, and the included angle between the magnetic field direction and the axial direction of the round wafer is 45°.

8. A modified dielectric ceramic material based on niobium-zirconium bimetallic element doped calcium copper titanate, characterized in that, The modified dielectric ceramic material is prepared by the preparation method in any one of claims 1 to 7, and the chemical formula of the niobium-zirconium bimetallic element doped calcium copper titanate is wherein, .

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