A BaBiO3 ceramic target material and its preparation method and application

Abstract

The invention provides a BaBiO3 ceramic target material and a preparation method and application thereof. The preparation method comprises the following steps: ball-milling a barium source and a bismuth source according to a formula amount to obtain a primary ball-milled material, calcining the primary ball-milled material to obtain a calcined material; cold isostatic pressing the calcined material to obtain a cold-pressed green block; hot-pressing and sintering the cold-pressed green block to obtain the BaBiO3 ceramic target material; the preparation method obtains a mixed powder by ball milling, obtains a formed cold green block by cold isostatic pressing, and obtains a high-density and high-performance NTC thermistor ceramic target material by hot-pressing and sintering, thereby solving the problems that the material obtained by the existing preparation process has a relatively large room temperature resistivity, poor stability, high production cost, and high requirements for sintering equipment, and obtains a BaBiO3 ceramic target material that can replace multi-component composite materials.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic target materials and relates to a BaBiO3 ceramic target material and a preparation method and application thereof. Background Art

[0002] Thermistor is a component that is sensitive to temperature or current. Thermistor materials can be divided into positive temperature coefficient (PTC) thermistor materials and negative temperature coefficient (NTC) thermistor materials according to the law of resistivity change with temperature. NTC thermistor materials are widely used in temperature compensation, temperature testing, and prevention of power-on surge current. For general-purpose NTC thermistor materials, the electronics industry basically selects 2 to 4 types of transition metal oxides from the Mn-Co-Ni-Cu-Fe series, and makes thermistors through traditional ceramic processes such as batching, molding, and sintering.

[0003] However, the thermistor component is a spinel structure, and when sintered at 1300°C or above, its room temperature resistivity is generally large and its stability is poor. Moreover, the surface content of these transition metal oxides is low, which will eventually increase the industrial production cost and is not suitable for industrial application. At present, there are many NTC thermistor materials other than spinel structure in the prior art, such as perovskite, rutile, fluorite, etc., but there is no disclosure of a composite material between two negative temperature coefficient thermistor materials.

[0004] With the development of high integrated circuits, the research and development of negative temperature coefficient (NTC) thermistors has gradually developed from polycrystalline ceramic blocks to more miniaturized and integrated film electronic components. A large number of thin film thermistor components are needed in highly integrated microelectronic circuits. Currently, the Mn-Ni based oxide system with AB2O4 spinel structure is more studied. The preparation of high-quality thermal sensitive films by magnetron sputtering depends on high-quality ceramic targets, among which perovskite ceramic targets such as BaBiO3 have high sensitivity and low temperature room temperature resistivity.

[0005] For example, CN 103787652A discloses a method for preparing a novel multiphase NTC thermistor material, the general chemical formula of which is xBaBiO3 / (1-x)[Ba 1-y Ca y (Fe 0.4 Ti 0.6 )O3], including BaO3, CaCO3, Bi2O3, TiO2, F e2 O3 is used as the main raw material, and BaBiO3 and BaO3 with negative temperature coefficient characteristics are synthesized in advance. 1-y Ca y (Fe 0.4 Ti 0.6 )O3, appropriate amount of BaBiO3 and Ba1-y Ca y (Fe 0.4 Ti 0.6 )O3 is uniformly mixed and sintered at 1260-1290℃. The composite material shows good NTC performance. The B value of the thermistor ceramic can reach above 4200K and is adjustable. The room temperature resistance is controllable. Moreover, the preparation process of the material is simple and feasible, the cost is low, and it is easy to produce.

[0006] CN 101402523A discloses a composite NTC thermistor ceramic material and a preparation method thereof, wherein BaCO3, SnO2 and Bi2O3 are used as main raw materials, BaSnO3 and BaBiO3 blanks are preliminarily solid-phase synthesized, BaSnO3 and BaBiO3 blanks are secondary mixed and ball-milled or the mixed blanks are doped with trace amounts of Sb2O3 and rare earth element oxides and then secondary ball-milled, and ordinary ceramic preparation processes are used to sinter and form at 1100-1300°C. Performance tests show that the prepared composite NTC thermistor ceramic has a B value of more than 5000K and a room temperature resistivity of 200Ω·m.

[0007] The ceramic materials disclosed in the above-mentioned prior art have the following defects: (1) they belong to a multi-component system and their uniformity is difficult to control; (2) the preparation process involves a high-temperature sintering furnace, which has high requirements for sintering equipment; (3) the sintering method of the existing process results in a low density of the obtained material; (4) the room temperature resistivity of the NTC thermistor material prepared by the existing process is large and the stability is poor.

[0008] Based on the above research, it is necessary to provide a method for preparing BaBiO3 ceramic target material. The material obtained by the preparation method has controllable room temperature resistivity, adjustable B value, high stability and low cost. The obtained binary material can replace the multi-component composite material. Summary of the invention

[0009] The object of the present invention is to provide a BaBiO3 ceramic target material and a preparation method and application thereof. The preparation method obtains a mixed powder by ball milling, obtains a formed cold billet by cold isostatic pressing, and then obtains a high-density and high-performance NTC thermistor ceramic target material by hot pressing and sintering. The problems that the material obtained by the existing preparation process has a relatively large room temperature resistivity, poor stability, high production cost, and high requirements for sintering equipment are solved, and a BaBiO3 ceramic target material that can replace multi-composite materials is obtained.

[0010] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a method for preparing a BaBiO3 ceramic target, the preparation method comprising the following steps:

[0012] (1) ball-milling a barium source and a bismuth source according to a formula amount to obtain a primary ball-milled material, and calcining the primary ball-milled material to obtain a calcined material;

[0013] (2) subjecting the calcined material in step (1) to cold isostatic pressing to obtain a cold pressed blank;

[0014] (3) hot pressing and sintering the cold pressed green block in step (2) to obtain the BaBiO3 ceramic target.

[0015] The preparation method described in the present invention firstly ball-mills the raw materials, then obtains a formed cold-pressed billet by cold isostatic pressing, and finally hot-presses and sinters the cold-pressed billet to obtain a NTC binary BaBiO3 ceramic target material with high density, controllable room temperature resistivity, adjustable B value, low cost and the ability to replace multi-composite materials. Compared with the conventional preparation method, the present invention hot-presses and sinters the cold-pressed billet, reduces the sintering temperature and the requirements for sintering equipment, and at the same time improves the density of the product, so that the density of the obtained BaBiO3 ceramic target material reaches more than 99%.

[0016] Preferably, the temperature of the hot pressing sintering in step (3) is 550-850°C, for example, 550°C, 650°C, 750°C or 850°C, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 550-700°C.

[0017] Preferably, the pressure of the hot pressing sintering in step (3) is 110-160 MPa, for example, 110 MPa, 120 MPa, 130 MPa, 140 MPa, 150 MPa or 160 MPa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] The present invention performs sintering after cold isostatic pressing under low temperature and high pressure, which not only improves the density and stability of the material, but also reduces the cost, so that the sintering after cold isostatic pressing does not need to be carried out at high temperature, and does not need to be carried out in a sintering device with high equipment requirements. At the same time, the temperature and pressure of the hot pressing sintering of the present invention cooperate with each other. If the temperature of the hot pressing sintering is too low, the ceramic material cannot be sintered to the required phase, and the sintering density will also be too low. The increase in sintering temperature can promote the migration and splicing of particles between particles, thereby increasing the contact area between particles, making the powder particles easy to sinter, and the sintering density will also increase accordingly. At the same time, high temperature can also promote the redox reaction, so that the chemical reaction of each phase in the sintered material is accelerated, which is also conducive to the sintering of the material. The increase in sintering temperature will promote the growth of grains, and the area of ​​the grain boundary will be reduced, so that the mechanical properties of the material are improved.

[0019] However, when the grains grow too large during the sintering process, brittle fracture is likely to occur, resulting in a decrease in mechanical properties. As the sintering temperature increases, the degree of expansion and combustion of the particles during the sintering process will decrease. At the same time, more capillaries will be generated inside the material, thereby affecting the densification of the material and increasing the residual porosity. If the temperature of hot pressing sintering is too high, it will cause the ceramic material to be overburned, the grains to grow rapidly, and it is easy to produce a brittle phase, which will cause the mechanical properties of the ceramic material to decrease and brittle fracture. The sintering pressure mainly affects the density of the ceramic material, and also affects the residual porosity of the ceramic material. The size of the residual porosity directly affects the strength and thermal conductivity of the material. With the increase of sintering pressure, the porosity can be greatly reduced and the density of the material can be improved. If the pressure of hot pressing sintering is too low, the material porosity is too large and the density is low, which in turn affects the material performance. If the pressure of hot pressing sintering is too high, it is easy to cause the material to crack brittlely.

[0020] Preferably, the hot pressing sintering time in step (3) is 2-5 hours, for example, 2 hours, 3 hours, 4 hours or 5 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Preferably, the hot pressing and sintering in step (3) is followed by grinding.

[0022] Preferably, before the cold isostatic pressing treatment in step (2), the calcined material is first subjected to secondary ball milling.

[0023] Preferably, the secondary ball milling is performed by dry ball milling.

[0024] Preferably, the rotation speed of the secondary ball milling is greater than the rotation speed of the primary ball milling in step (1).

[0025] The present invention carries out ball milling in multiple steps and in different ways. On the one hand, the uniformity of the material composition can be fully improved, thereby improving the performance of the obtained BaBiO3 ceramic target. On the other hand, since the hot pressing sintering of the present invention is also carried out under high pressure, the uniformity of the particles will affect the effect of hot pressing sintering. In order to ensure the stability and density of the material, a second ball milling is carried out after calcination and before cold isostatic pressing. In addition, the second ball milling of the present invention is dry ball milling, which avoids the introduction of solvent. Compared with the first ball milling, it is carried out at a higher speed to match the subsequent cold isostatic pressing and hot pressing sintering steps. The first ball milling of step (1) is wet ball milling, which also needs to be dried and ground, so the speed is lower than that of the second ball milling.

[0026] Preferably, the secondary ball milling speed is 350-550 r / min, for example, 350 r / min, 450 r / min or 550 r / min, and the time is 12-24 h, for example, 12 h, 16 h, 20 h or 24 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the material-ball ratio of the secondary ball milling is (2-5):1, for example, 2:1, 3:1, 4:1 or 5:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the pressure of the cold isostatic pressing in step (2) is 200-300 MPa, for example, 200 MPa, 250 MPa or 300 MPa, and the time is 5-40 min, for example, 5 min, 20 min or 40 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the primary ball mill material in step (1) is dried and ground before calcination.

[0030] In the present invention, ethanol is added during the first ball milling. In order to avoid the problem of the solvent causing powder agglomeration, the ball milled material of the first ball milling is directly dried and then ground, which not only improves the uniformity of the material, but also improves the uniformity of the distribution of the particle size.

[0031] Preferably, the drying temperature is 50-100°C, for example, 50°C, 75°C or 100°C, and the drying time is 10-16h, for example, 10h, 12h, 14h or 16h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the grinding time is 1-4 h, for example, 1 h, 2 h, 3 h or 4 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the barium source and bismuth source in step (1) are subjected to a drying pretreatment before being ball-milled.

[0034] The raw materials of the present invention are dried before ball milling to remove the moisture physically adsorbed on the surface and reduce the agglomeration of powders.

[0035] Preferably, the temperature of the pre-drying treatment is above 105°C, for example, 105°C, 125°C, 135°C or 145°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 105-140°C.

[0036] Preferably, the pre-drying treatment time is 3-7 hours, for example, 3 hours, 4 hours, 5 hours, 6 hours or 7 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] Preferably, the purity of the barium source in step (1) is above 99.9%, for example, it can be 99.9%, 99.92%, 99.94%, 99.96% or 99.99%, and the particle size D50 is 0.5-1.5 μm, for example, it can be 0.5 μm, 1.0 or 1.5 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] Preferably, the purity of the bismuth source in step (1) is above 99.9%, for example, it can be 99.9%, 99.92%, 99.94%, 99.96% or 99.99%, and the particle size D50 is 1.5-3.5 μm, for example, it can be 1.5 μm, 2.5 or 3.5 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] The invention adopts high-purity raw materials for preparation and adopts matching of particle sizes to further improve the performance of the obtained material.

[0040] Preferably, the barium source comprises BaCO3, and the bismuth source comprises Bi2O3.

[0041] Preferably, the first ball milling in step (1) is performed by wet ball milling.

[0042] Preferably, the rotation speed of the first ball milling in step (1) is 150-250 r / min, for example, 150 r / min, 200 r / min or 250 r / min, and the time is 12-24 h, for example, 12 h, 18 h or 24 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] Preferably, the material-to-ball ratio of the first ball milling in step (1) is (5-7):1, for example, it can be 5:1, 6:1 or 7:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the calcination temperature in step (1) is 450-650°C, such as 450°C, 550°C or 650°C, the calcination time is 8-10h, such as 8h, 9h or 10h, and the atmosphere is air.

[0045] As a preferred technical solution of the preparation method of the present invention, the preparation method comprises the following steps:

[0046] (1) Pre-drying the barium source and the bismuth source at a temperature above 105° C. for 3-7 hours according to the formula amount, and then ball milling for 12-24 hours at a rotation speed of 150-250 r / min and a material-ball ratio of (5-7):1 to obtain a primary ball mill material, drying the primary ball mill material at 50-100° C. for 10-16 hours, and then grinding it for 1-4 hours, and then calcining the ground mill material in an air atmosphere at a temperature of 450-650° C. for 8-10 hours to obtain a calcined material;

[0047] (2) subjecting the calcined material of step (1) to secondary ball milling for 12-24 h at a rotation speed of 350-550 r / min and a material-to-ball ratio of (2-5):1, and then subjecting the obtained secondary ball milled material to cold isostatic pressing for 5-40 min at a pressure of 200-300 MPa to obtain a cold pressed block;

[0048] (3) hot pressing and sintering the cold pressed green block in step (2) at 550-850° C. and 110-160 MPa for 2-5 h, and then grinding the green block to obtain the BaBiO3 ceramic target.

[0049] In a second aspect, the present invention provides a BaBiO3 ceramic target material, wherein the BaBiO3 ceramic target material is obtained by the preparation method described in the first aspect.

[0050] In a third aspect, the present invention provides a thermistor, wherein the thermistor comprises the BaBiO3 ceramic target material as described in the second aspect.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The invention obtains a mixed powder by ball-milling a barium source and a bismuth source for multiple times, obtains a formed cold billet by cold isostatic pressing, and obtains a high-density and high-performance NTC thermistor ceramic target by hot-pressing, sintering and grinding. The invention solves the problems that thermistor ceramics prepared by the traditional industry have a relatively large room temperature resistivity, poor stability, high production cost and high requirements for sintering equipment, and obtains a binary thermistor material that can replace multi-component composite materials, has controllable room temperature resistivity, adjustable B value and low cost, and the density of the material is above 99%. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] Example 1

[0055] This embodiment provides a method for preparing a BaBiO3 ceramic target, the preparation method comprising the following steps:

[0056] (1) According to the formula amount, a barium source (3946 g) and a bismuth source (4660 g) were dried at 110° C. for 5 h, and then ball-milled for 12 h at a rotation speed of 250 r / min and a material-to-ball ratio of 6.3:1 to obtain a primary ball-milled material, and the primary ball-milled material was first dried at 80° C. for 12 h, and then ground for 2 h, and then the ground material obtained by grinding was calcined in an air atmosphere at a temperature of 550° C. for 9 h to obtain a calcined material;

[0057] Wherein, the barium source is BaCO3 with a purity of 99.9% and a particle size D50 of 1 μm, and the bismuth source is Bi2O3 with a purity of 99.9% and a particle size D50 of 2 μm;

[0058] The primary ball milling method is wet ball milling, and zirconium oxide balls and anhydrous ethanol in an amount of 10% of the total mass of the ball mill material are used for primary ball milling;

[0059] (2) subjecting the calcined material of step (1) to secondary ball milling for 18 h at a rotation speed of 350 r / min and a material-to-ball ratio of 3:1, and then subjecting the secondary ball milled material to cold isostatic pressing for 20 min at a pressure of 250 MPa to obtain a cold pressed block;

[0060] The secondary ball milling method is dry ball milling;

[0061] (3) The cold pressed green block of step (2) is hot pressed and sintered at 650° C. and a pressure of 140 MPa for 3 h, and then ground to obtain the BaBiO3 ceramic target.

[0062] Example 2

[0063] This embodiment provides a method for preparing a BaBiO3 ceramic target, the preparation method comprising the following steps:

[0064] (1) According to the formula, a barium source (3946 g) and a bismuth source (4660 g) were dried at 105° C. for 7 h, and then ball-milled for 24 h at a rotation speed of 250 r / min and a material-to-ball ratio of 7:1 to obtain a primary ball-milled material. The primary ball-milled material was first dried at 100° C. for 10 h, and then ground for 4 h. The ground material was then calcined in an air atmosphere at 650° C. for 8 h to obtain a calcined material.

[0065] The barium source is BaCO3 with a purity of 99.92% and a particle size D50 of 1.5 μm, and the bismuth source is Bi2O3 with a purity of 99.9% and a particle size D50 of 3.5 μm;

[0066] The primary ball milling method is wet ball milling, and zirconium oxide balls and anhydrous ethanol in an amount of 10% of the total mass of the ball mill material are used for primary ball milling;

[0067] (2) The calcined material in step (1) was subjected to secondary ball milling at a rotation speed of 550 r / min and a material-to-ball ratio of 5:1 for 24 h, and the secondary ball milled material was subjected to cold isostatic pressing at a pressure of 200 MPa for 40 min to obtain a cold pressed block;

[0068] The secondary ball milling method is dry ball milling;

[0069] (3) The cold pressed green block of step (2) is hot pressed and sintered at 850° C. and a pressure of 110 MPa for 2 h, and then ground to obtain the BaBiO3 ceramic target.

[0070] Example 3

[0071] This embodiment provides a method for preparing a BaBiO3 ceramic target, the preparation method comprising the following steps:

[0072] (1) According to the formula, a barium source (3946 g) and a bismuth source (4660 g) were dried at 120° C. for 3 h, and then ball-milled for 12 h at a rotation speed of 150 r / min and a material-to-ball ratio of 5:1 to obtain a primary ball-milled material. The primary ball-milled material was first dried at 50° C. for 16 h, and then ground for 1 h. The ground material was then calcined in an air atmosphere at 450° C. for 10 h to obtain a calcined material.

[0073] Wherein, the barium source is BaCO3 with a purity of 99.9% and a particle size D50 of 0.5 μm, and the bismuth source is Bi2O3 with a purity of 99.9% and a particle size D50 of 1.5 μm;

[0074] The primary ball milling method is wet ball milling, and zirconium oxide balls and anhydrous ethanol in an amount of 10% of the total mass of the ball mill material are used for primary ball milling;

[0075] (2) subjecting the calcined material of step (1) to secondary ball milling for 12 h at a rotation speed of 350 r / min and a material-to-ball ratio of 2:1, and then subjecting the secondary ball milled material to cold isostatic pressing for 5 min at a pressure of 300 MPa to obtain a cold pressed block;

[0076] The secondary ball milling method is dry ball milling;

[0077] (3) The cold pressed block of step (2) is hot pressed and sintered at 550° C. and a pressure of 160 MPa for 5 h, and then ground to obtain the BaBiO3 ceramic target.

[0078] Example 4

[0079] This embodiment provides a method for preparing a BaBiO3 ceramic target. The preparation method is the same as that of Embodiment 1 except that the hot pressing sintering temperature in step (3) is 850°C.

[0080] Example 5

[0081] This embodiment provides a method for preparing a BaBiO3 ceramic target. The preparation method is the same as that of Embodiment 1 except that the hot pressing sintering temperature in step (3) is 400°C.

[0082] Example 6

[0083] This embodiment provides a method for preparing a BaBiO3 ceramic target. The preparation method is the same as that of Embodiment 1 except that the temperature of the hot pressing sintering in step (3) is 1000°C.

[0084] Example 7

[0085] This embodiment provides a method for preparing a BaBiO3 ceramic target. The preparation method is the same as that of Embodiment 1 except that the pressure of the hot pressing sintering in step (3) is 90 MPa.

[0086] Example 8

[0087] This embodiment provides a method for preparing a BaBiO3 ceramic target. The preparation method is the same as that of Embodiment 1 except that the pressure of the hot pressing sintering in step (3) is 180 MPa.

[0088] Example 9

[0089] This embodiment provides a method for preparing a BaBiO3 ceramic target. The preparation method is the same as that of Embodiment 1 except that the rotation speed of the secondary ball milling in step (2) is the same as that of the primary ball milling.

[0090] Example 10

[0091] This embodiment provides a method for preparing a BaBiO3 ceramic target material. The preparation method is the same as that of Embodiment 1 except that the secondary ball milling in step (2) is performed by wet ball milling. During the wet ball milling, anhydrous ethanol is added in an amount of 10% of the mass of the ball milling material.

[0092] Embodiment 11

[0093] This embodiment provides a method for preparing a BaBiO3 ceramic target. The preparation method is the same as that of Embodiment 1 except that step (2) does not involve secondary ball milling.

[0094] Example 12

[0095] This embodiment provides a method for preparing a BaBiO3 ceramic target. The preparation method is the same as that of Embodiment 1, except that no drying and grinding are performed after the first ball milling in step (1).

[0096] Example 13

[0097] This embodiment provides a method for preparing a BaBiO3 ceramic target. The preparation method is the same as that of Embodiment 1 except that the barium source and the bismuth source in step (1) are not subjected to a drying pre-treatment.

[0098] Comparative Example 1

[0099] This comparative example provides a method for preparing a BaBiO3 ceramic target material, which is the same as Example 1 except that in step (2), the cold pressed green block is sintered at normal pressure and a temperature of 700°C instead of hot pressing.

[0100] Comparative Example 2

[0101] This comparative example provides a method for preparing a BaBiO3 ceramic target material, which is the same as Example 1 except that in step (2), the cold pressed green block is sintered at normal pressure and a temperature of 1200°C instead of hot pressing.

[0102] The room temperature resistivity and density of the BaBiO3 ceramic targets obtained in the above examples and comparative examples are shown in Table 1:

[0103] Table 1

[0104]

[0105]

[0106] From the above table we can see that:

[0107] The BaBiO3 ceramic target material obtained by the present invention has high density and excellent performance, with a room temperature resistivity of less than 3.5Ω·m and a density of more than 99%; specifically, it can be seen from Example 1 and Comparative Examples 1-2 that the sintering of the cold-pressed green blocks at normal pressure is not only costly, but also fails to obtain a ceramic target material with high density and performance; it can be seen from Example 1 and Examples 4-8 that the temperature and pressure of the hot pressing sintering of the present invention are within a specific range, which can further improve the density and performance of the target material; it can be seen from Example 1 and Examples 9-11 that the preferred secondary ball milling method of the present invention is dry ball milling, which can avoid the introduction of solvent to cause powder agglomeration, and the rotation speed of the secondary ball milling is preferably greater than that of the primary ball milling; from Example 1 and Examples 12-13, drying and grinding are performed after the primary ball milling, and the raw materials are first dried before treatment, which can further improve the uniformity, density and performance of the material.

[0108] In summary, the present invention provides a BaBiO3 ceramic target material and a preparation method and application thereof. The preparation method obtains a mixed powder by ball milling, obtains a formed cold billet by cold isostatic pressing, and then obtains a high-density and high-performance NTC thermistor ceramic target material by hot pressing and sintering. The problems of the materials obtained by the existing preparation process having a relatively large room temperature resistivity, poor stability, high production cost, and high requirements for sintering equipment are solved, and a BaBiO3 ceramic target material that can replace the multi-composite material is obtained.

[0109] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a BaBiO3 ceramic target, characterized in that: The preparation method comprises the following steps: (1) ball-milling a barium source and a bismuth source according to a formula amount to obtain a primary ball-milled material, and calcining the primary ball-milled material to obtain a calcined material; The barium source and the bismuth source are first subjected to drying pretreatment before the first ball milling; the first ball milling method is wet ball milling; the speed of the first ball milling is 150-250r / min, and the time is 12-24h; the first ball mill material is first dried and ground before calcination; (2) subjecting the calcined material in step (1) to cold isostatic pressing to obtain a cold pressed block; Before the cold isostatic pressing treatment, the calcined material is subjected to secondary ball milling; the secondary ball milling is performed by dry ball milling; the rotation speed of the secondary ball milling is 350-550 r / min, and the time is 12-24 h; (3) hot pressing and sintering the cold pressed compact in step (2) to obtain the BaBiO3 ceramic target; The temperature of the hot pressing sintering is 550-700° C.; the pressure of the hot pressing sintering is 110-160 MPa.

2. The preparation method according to claim 1, characterized in that: The hot pressing sintering time in step (3) is 2-5 hours.

3. The preparation method according to claim 1, characterized in that: In step (3), the hot pressing and sintering is followed by grinding.

4. The preparation method according to claim 1, characterized in that: The material-to-ball ratio of the secondary ball milling is (2-5):

1.

5. The preparation method according to claim 1, characterized in that: The cold isostatic pressing pressure in step (2) is 200-300 MPa and the time is 5-40 min.

6. The preparation method according to claim 1, characterized in that: The drying temperature is 50-100° C. and the drying time is 10-16 hours.

7. The preparation method according to claim 1, characterized in that: The grinding time is 1-4h.

8. The preparation method according to claim 1, characterized in that: The temperature of the pre-drying treatment is above 105°C.

9. The preparation method according to claim 8, characterized in that: The temperature of the pre-drying treatment is 105-140°C.

10. The preparation method according to claim 1, characterized in that: The time of the pre-drying treatment is 3-7h.

11. The preparation method according to claim 1, characterized in that: The purity of the barium source in step (1) is above 99.9%, and the particle size D50 is 0.5-1.5 μm.

12. The preparation method according to claim 1, characterized in that: The purity of the bismuth source in step (1) is above 99.9%, and the particle size D50 is 1.5-3.5 μm.

13. The preparation method according to claim 1, characterized in that: The material-to-ball ratio of the first ball milling in step (1) is (5-7):

1.

14. The preparation method according to claim 1, characterized in that: The calcination temperature in step (1) is 450-650°C, the calcination time is 8-10 hours, and the atmosphere is air.

15. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: (1) Pre-drying the barium source and the bismuth source at a temperature above 105° C. for 3-7 hours according to the formula amount, and then ball milling for 12-24 hours at a rotation speed of 150-250 r / min and a material-ball ratio of (5-7):1 to obtain a primary ball mill material, drying the primary ball mill material at 50-100° C. for 10-16 hours, grinding it for 1-4 hours, and then calcining the ground mill material in an air atmosphere at a temperature of 450-650° C. for 8-10 hours to obtain a calcined material; (2) The calcined material of step (1) is subjected to secondary ball milling for 12-24 hours at a rotation speed of 350-550 r / min and a material-to-ball ratio of (2-5):1, and the secondary ball milled material is subjected to cold isostatic pressing for 5-40 minutes at a pressure of 200-300 MPa to obtain a cold pressed block; (3) The cold pressed green block of step (2) is hot pressed and sintered at 550-700° C. and 110-160 MPa for 2-5 h, and then ground to obtain the BaBiO3 ceramic target.

16. A BaBiO3 ceramic target, characterized in that: The BaBiO3 ceramic target is obtained by the preparation method as described in any one of claims 1-15.

17. A thermistor ceramic resistor, characterized in that: The thermistor ceramic resistor comprises the BaBiO3 ceramic target as claimed in claim 16.

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