NL2030121A

NL2030121A - Method for preparing large-size high-quality potassium tantalum niobate ceramic target material

Info

Publication number: NL2030121A
Application number: NL2030121A
Authority: NL
Inventors: Liu Bing; Qiu Chengcheng; Yang Yuguo; Zuo Xianggang; Wang Xuping; Zhang Shaodong
Original assignee: Advanced Mat Institute Shandong Academy Of Sciences; Shandong Shanke Smart Crystal Optoelectronic Tech Co Ltd
Priority date: 2021-11-30
Filing date: 2021-12-13
Publication date: 2023-06-16
Also published as: NL2030121B1; CN113956039B; CN113956039A

Abstract

The invention relates to a method for preparing a large-size high-quality potassium tantalum niobate ceramic target material. The method includes: cleaning potassium tantalum niobate crystal wastes to obtain a ceramic precursor, crushing and sieving the ceramic precursor to obtain precursor powder, performing granulation after miXing the precursor powder with a binder, and sequentially performing dry pressing, heating for debinding and sintering on the granulated powder to obtain the large-size high-quality potassium tantalum niobate ceramic target material. The process of cleaning the potassium tantalum niobate crystal wastes comprises: soaking the potassium tantalum niobate crystal wastes in an acid solution to remove alkaline components. In the invention, the potassium tantalum niobate crystal wastes are used as the raw materials, so reasonable resource recycle is realized. No solid phase reaction occurs during the preparation process. The sintering time is short. The prepared ceramic target material has uniform phases and a controllable size.

Description

METHOD FOR PREPARING LARGE-SIZE HIGH-QUALITY POTASSIUM

TANTALUM NIOBATE CERAMIC TARGET MATERIAL

Field of the Invention

The present invention belongs to the field of inorganic nonmetallic materials, relates to the preparation of artificial crystals and functional ceramic materials, and specifically relates to a method for preparing a large-size high-quality potassium tantalum niobate ceramic target material.

Background of the Invention

The information in the background art is disclosed only to increase the understanding of the overall background of the present invention, and is not necessarily regarded as an acknowledgement or any form of implication that the information constitutes the prior art known to those of ordinary skill in the art.

Potassium tantalum niobate (KTa;Nb,O3; 0<x<1, KTN for short) ceramic chips are generally made of metal oxides such as K,COs, Ta>Os and Nb2Os by sintering via a solid phase reaction.

The inventors found via researches that, due to the infinite solid solution characteristics of KTN crystals, the internal crystal structures of potassium tantalate (KTaO;, KT) and potassium niobate (KNbO;, KN) are quite different, resulting in a complex internal structure of the material. The

KTN crystals can exist in either a paraelectric phase or a ferroelectric phase (a tetragonal phase or an orthogonal phase) at room temperature depending on different internal Ta/Nb ratios. Since the solid phase reaction cannot realize free ion transport, it is difficult to realize uniform distribution of Ta/Nb in KTN ceramics synthesized by sintering, resulting in complex phases of the KTN ceramic chips; and at the same time, due to the release of a CO, gas from the solid phase reaction, pores are formed inside the ceramic chips, resulting in worse density of the ceramic chips. In summary, due to the inhomogeneity of the phases and the poor density, the

KTN ceramics prepared from a solid phase reaction method are difficult to meet the application requirements of a KTN target material.

Summary of the Invention -1-

In order to solve the shortcomings of the prior art, the objective of the present invention is to provide a method for preparing a large-size high-quality potassium tantalum niobate ceramic target material, which can provide a high-quality target source for high-quality KTN thin film materials.

In order to achieve the above objective, the technical solutions of the present invention are as follows:

In one aspect, provided is an application of potassium tantalum niobate crystal wastes as raw materials for preparing a potassium tantalum niobate ceramic target material.

A KTN monocrystal is another KTN target source for sputtering, it is a solid solution mixed crystal of KT and KN crystals, and is generally prepared from a melt method. However, due to the infinite solid-melt characteristics of KTN crystals, the yield of the KTN monocrystals is relatively low, and the KTN monocrystals that do not meet the standards for optical, piezoelectric and dielectric applications can only be treated as scraps and are discarded; while the available

KTN monocrystals have a lower utilization rate (generally, the utilization rate of the KTN crystal is less than 50% after processing) due to the higher requirements for crystal orientations and sizes, such that there are more leftovers. The potassium tantalum niobate crystal wastes of the present invention are KTN monocrystals that do not meet the standards for optical, piezoelectric and dielectric applications in a process of preparing the KTN monocrystals by using the melt method, and leftovers that cannot be used after the preparation of the KTN monocrystals.

In the present invention, the potassium tantalum niobate crystal wastes are used as the raw materials for preparing the potassium tantalum niobate ceramic target material, thereby avoiding a solid phase reaction and preventing gas release from causing pores in ceramic chips, therefore the problem of worse density of the ceramic chips is solved, further, the sintering time is short, and the cost 1s lower.

At the same time, by using the potassium tantalum niobate crystal wastes as the raw materials, reasonable resource recycle is realized, and a role of "turning waste into treasure" is implemented.

In another aspect, provided is a method for preparing a large-size high-quality potassium tantalum niobate ceramic target material, including: cleaning potassium tantalum niobate crystal wastes to obtain a ceramic precursor, crushing and sieving the ceramic precursor to obtain “7 precursor powder, performing granulation after mixing the precursor powder with a binder, and sequentially performing dry pressing, heating for debinding and sintering on the granulated powder to obtain the large-size high-quality potassium tantalum niobate ceramic target material, wherein the process of cleaning the potassium tantalum niobate crystal wastes includes: soaking the potassium tantalum niobate crystal wastes in an acid solution to remove alkaline components.

In a preparation process of the KTN monocrystals, there are defects or cavities in the crystal lattice, or there are gaps between the formed crystals, such that the raw materials are filled therein to form inclusions; at the same time, in a growth process of the KTN monocrystals, micro-cracks are generated under stress, recrystallization is likely to occur in the micro-cracks, the inclusions can also be formed, these inclusions affect the growth of the KTN monocrystals, and studies have shown that, these inclusion defects affect the preparation of the phases of the potassium tantalum niobate ceramic target material, and at the same time, these inclusion defects will also affect the uniform distribution of Ta/Nb, resulting in more complex phases of the formed KTN ceramic chip. Further studies have shown that these inclusion defects are mainly alkaline components. Therefore, the present invention can remove the inclusion defects by soaking in the acid solution, which can not only ensure the uniformity of the phases of the prepared KTN ceramics, but also eliminates the increase in the sintering time caused by the inclusion defects.

In a third aspect, a potassium tantalum niobate ceramic target material is obtained by the above-mentioned preparation method.

The potassium tantalum niobate ceramic target material obtained by the above preparation method of the present invention has uniform phases, high density and a larger size, and thus can better meet the application requirements of the KTN target material.

In a fourth aspect, provided is an application of the above-mentioned potassium tantalum niobate ceramic target material as a target material for preparing a KTN thin film material.

The beneficial effects of the present invention are as follows: (1) The raw materials used in the embodiments of the present invention are KTN crystal leftovers discarded during crystal processing, or grown KTN crystals with poor quality, thereby saving the cost, being environmentally friendly, and having a very bright promotion prospect. (2) The large-size dense potassium tantalum niobate ceramic target material provided by the embodiments of the present invention has a short sintering time, uniform phases, high density and a controllable size, thereby having a very wide application range.

Brief Description of the Drawings

The drawings constituting a part of the present invention are used for providing a further understanding of the present invention. The exemplary embodiments of the present invention and the descriptions thereof are used for explaining the present invention, but do not constitute improper limitations of the present invention.

FIG. 1 is an X-ray diffraction diagram of a KTN ceramic target material prepared in Examples 1 to 3 of the present invention; and

FIG. 2 1s a scanning electron microscope image of a KTN ceramic chip provided in Example 1 of the present invention.

Detailed Description of the Embodiments

It should be pointed out that, the following detailed descriptions are all exemplary and are intended to provide a further description of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

It should be noted that, the terms used here are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that, when the terms "comprising" and/or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and/or combinations thereof.

The potassium tantalum niobate crystal or monocrystal of the present invention has an Nb composition of 0<x<1, the crystal phase is cubic (m3m), tetragonal (4mm) or orthogonal (mm?2), and the doping ions are Cu, Fe, Sn, Ti, Li, Na and Mn single-doped or mixed multi-doped

KTa;xNbyO; or M:KTa;.Nb,O; crystals.

In view of the problems of phase inhomogeneity and poor density of the existing potassium tantalum niobate ceramic target materials, the present invention proposes a method for preparing -4-

a large-size high-quality potassium tantalum niobate ceramic target material.

A typical embodiment of the present invention provides an application of potassium tantalum niobate crystal wastes as raw materials for preparing a potassium tantalum niobate ceramic target material.

In the present invention, the potassium tantalum niobate crystal wastes are used as the raw materials for preparing the potassium tantalum niobate ceramic target material, thereby avoiding a solid phase reaction and preventing gas release from causing pores in ceramic chips, therefore the problem of worse density of the ceramic chips is solved, further, the sintering time is short, and the cost is lower.

IO At the same time, the currently prepared available KTN monocrystals have higher requirements, higher rejection rate and lower utilization rate, therefore, it is easier to obtain the potassium tantalum niobate crystal wastes as the raw materials in the present invention.

Another embodiment of the present invention provides a method for preparing a large-size high-quality potassium tantalum niobate ceramic target material, including: cleaning potassium tantalum niobate crystal wastes to obtain a ceramic precursor, crushing and sieving the ceramic precursor to obtain precursor powder, performing granulation after mixing the precursor powder with a binder, and sequentially performing dry pressing, heating for debinding and sintering on the granulated powder to obtain the large-size high-quality potassium tantalum niobate ceramic target material, wherein the process of cleaning the potassium tantalum niobate crystal wastes includes: soaking the potassium tantalum niobate crystal wastes in an acid solution to remove alkaline components.

The present invention can remove inclusion defects by soaking in the acid solution, which can not only ensure the uniformity of the phases of the prepared KTN ceramics, but also eliminates the increase in the sintering time caused by the inclusion defects.

In some examples of the embodiment, the acid solution is dilute hydrochloric acid. The dilute hydrochloric acid in the present invention is hydrochloric acid with a mass fraction less than 20%, thereby avoiding the corrosion of the potassium tantalum niobate crystals.

In some examples of the embodiment, the process of cleaning the potassium tantalum niobate crystal wastes includes: soaking the potassium tantalum niobate crystal wastes in acetone. This step is used for removing impurities such as 502 glue and paint remaining during crystal processing. The soaking time is preferably 2-3 h.

In some examples of the embodiment, the process of cleaning the potassium tantalum niobate crystal wastes includes: soaking the potassium tantalum niobate crystal wastes in an alcoholic solution. This step is used for removing binders such as gum and wax, as well as organic impurities such as leftovers of KTN crystal processing, which are left on the surfaces during crystal processing. The soaking time is preferably 2-3 h. The concentration of the alcoholic solution is 95-99.5% (volume percentage).

In some examples of the embodiment, the process of cleaning the potassium tantalum niobate crystal wastes includes water washing. This step is used for removing impurity ions. Water washing is performed after the potassium tantalum niobate crystal wastes are soaked in the acid solution to remove the alkaline components. The water washing times are reduced, the procedures are simplified, and water is saved.

In some examples of the embodiment, the potassium tantalum niobate crystal wastes are dried after being cleaned.

In order to improve the material performance, reduce the sintering temperature and improve the sintering quality, the raw materials should be crushed for the purpose of obtaining high-purity ultra-fine powder as much as possible. Therefore, it is necessary to clean the potassium tantalum niobate crystal wastes in the present invention. In order to ensure the powder size, ball milling crushing is generally used. However, impurities are inevitably introduced in the ball milling crushing process. In order to reduce the contamination of impurities caused by ball milling, the grinding time should not be too long. Therefore, in some examples of the embodiment, during the process of crushing and sieving, the ball milling time is 22-26 h. In a ball milling process, the mass ratio of grinding balls to the ceramic precursor is 2:0.9 to 1.1. In order to better avoid the introduction of impurities, the grinding balls are agate grinding balls. The rotating speed of ball milling is preferably 100-150 r/min. The particle size of the precursor powder is preferably 200-300 meshes. When the particle size is too large, the process of crushing and sieving can be repeated.

The preparation process of the ceramic target material requires that the particle size of the raw material is as fine as possible, so ball milling crushing is required. However, the finer the powder is, the worse the fluidity is. At the same time, the specific surface area of the raw material is -6-

large, and the volume occupied is also large, therefore, the raw material cannot be uniformly filled in a steel mold during dry pressing, so it is difficult to realize preform and compactness. A granulation process is usually used, that is, the binder and the powder are fully mixed, and then sieving is performed to process coarse powder particles with good fluidity. The binder is generally an organic compound with bonding properties, and its additional significant function is to increase the plasticity and strength of the green body. In some examples of the embodiment, the granulation process is as follows: the precursor powder and the binder are heated until the binder is melted, are mixed evenly, and then are sieved. The heating temperature should not be too high to prevent an excessive loss of the binder due to excessive heating. It is better to control the heating temperature so that the binder just melts, which can be 1-10°C higher than the melting temperature. After melting, stirring is performed to make the precursor powder and the binder evenly mixed. The purpose of sieving is to make the size of the particles similar to ensure the uniformity of the material; after the granulation is completed, the obtained powder should have better fluidity, so that it is convenient to use the steel mold to prepare compact and uniform wafers and cylinders. The mesh number of sieving is 70-90 meshes. The binder described in the present invention can be paraffin, a polyvinyl alcohol solution and the like. When the polyvinyl alcohol solution is used as the binder, since the polyvinyl alcohol solution itself is liquid, it is sufficient to ensure the room temperature during the granulation process.

The granulated powder is tabletted by a unidirectionally pressurized mold, the pressure in the mold will have a significant pressure gradient, and a pressure difference will also appear in the green body. Generally speaking, the greater the forming pressure is, the smaller the distance between the powder particles is, the easier it is to sinter; however, if the forming pressure is too large and exceeds the plastic deformation limit of the material, brittle fracture will appear on the green body. In some examples of the embodiment, the pressure of dry pressing is 38-42 MPa. A circular steel mold with a diameter of 30 mm can be used for dry pressing.

In a calcining process of the green body mixed with the organic binder, the organic binder needs to undergo processes such as melting, decomposition and volatilization in the green body, which will cause the green body to deform and crack, and the mechanical strength will also be reduced.

Since the organic binder contains more carbon, when oxygen is insufficient to produce a reducing atmosphere, the sintering quality will be affected, thereby reducing the quality of a 7 -

ceramic sample, and affecting the final performance of the product. Therefore, debinding needs to be performed on the green body before calcination. Since there are many factors that affect the debinding process, in actual operation, it is necessary to comprehensively formulate the process flow of the debinding process according to the number and type of the binder, the size and shape of the green body, and the nature of the ingredients. In some examples of the embodiment, in an air atmosphere, the temperature is programmed to 500-800°C, and the temperature is kept. The heating rate is 1-2°C/min. The heat preservation time is 2-3 h. For example, when the binder is paraffin, the heating rate is 1°C/min, the temperature is increased to 500°C, and the temperature is kept at 500°C for 2 h to discharge the paraftin used as the binder in the green body. When the binder is a polyvinyl alcohol solution, the heating rate is 2°C/min, the temperature is increased to 750°C, and the temperature is kept at 750°C for 2h to discharge the polyvinyl alcohol used as the binder in the green body. When the paraffin is used as the binder, the additive amount of the paraffin is 8-10% of the mass of the precursor powder. When the polyvinyl alcohol solution 1s used as the binder, the additive amount of the polyvinyl alcohol solution is 1 to 2 drops of the polyvinyl alcohol solution per gram of the precursor powder. The mass fraction of polyvinyl alcohol solution is 6-8%.

The bonding between the particles of the green body formed by the powder mainly depends on mechanical occlusion or bonding of a plasticizer, and the strength of the green body is not high.

The green body is heated at a certain temperature to transform the mechanical occlusion between the particles into bonding directly relying on ionic bonds and covalent bonds, which greatly improves the strength of the material, and this process is sintering. The sintering of the ceramic material 1s divided into three stages, that is, a heating stage, a heat preservation stage and a cooling stage. In the heating stage, microscopic phenomena such as emission of volatiles, decomposition and oxidation of the organic binder, generation of a liquid phase, and rearrangement and growth of crystal grains often occur in the green body. In operation, considering the elimination of the volatiles during sintering and the life of a sintering furnace, different heating rates are required in different stages. The heat preservation stage refers to a process in which a parison is maintained at the highest temperature (usually called a sintering temperature). The sintering of the powder involves a solid phase mass transfer process. It is a thermal activation process, and the higher the temperature is, the faster the sintering is. The -8-

sintering temperature is related to the crystalline chemical characteristics of the material, the lattice energy is large, and a mass point is difficult to move at a high temperature, which is not conducive to the sintering. The cooling stage is a process in which the ceramic material is cooled from the highest temperature to the room temperature. The cooling process is accompanied by physical and chemical changes such as liquid phase solidification, crystallization and phase change. The cooling manner and the cooling speed have a great influence on the composition, structure and performance of the final phase of the ceramic material.

During the sintering, if the temperature is too high, the green body may melt and deform, if the sintering temperature is too low, the sintering is not sufficient, the bonding between the material particles is not tight, and there are a lot of pores between the crystal grains, which is not conducive to further improving the density of the ceramic. In some examples of the embodiment, the temperature is programmed to 850-950°C, the temperature is kept for a set time, then the temperature is further increased to 1150-1200°C, and the temperature is lowered after the temperature is kept for the set time. The heating rate for heating up to 850-950°C is preferably 4-6°C/min. The heat preservation time after heating up to 850-950°C is preferably 0.5-1.5 h. The heating rate for heating up to 1150-1200°C is preferably 4-6°C/min. The heat preservation time after heating up to 1150-1200°C is preferably 2-3 h. The rate of cooling to the room temperature is 4-6°C/min.

The third embodiment of the present invention provides a potassium tantalum niobate ceramic target material obtained by the above-mentioned preparation method.

The potassium tantalum niobate ceramic target material obtained by the above-mentioned preparation method of the present invention has uniform phases, high density and a large size, and thus can better meet the application requirements of the KTN target material.

The fourth embodiment of the present invention provides an application of the above-mentioned potassium tantalum niobate ceramic target material as a target material for preparing a KTN thin film material.

In order that those skilled in the art can understand the technical solutions of the present invention more clearly, the technical solutions of the present invention will be described in detail below in conjunction with specific examples.

Example 1 29.

A method for preparing a potassium tantalum niobate ceramic target material includes the following steps: 1) cleaning and preparing materials: taking an appropriate amount of leftovers discarded in the process of KTN crystal processing, respectively soaking the leftovers in an acetone solution, an alcoholic solution and dilute hydrochloric acid (with a mass fraction of 10%) for 2 h to remove 502 glue, gum, paraffin and other organic binders, and alkaline components, and then rinsing the leftovers with deionized water for 3 times to remove acetone, alcohol and dilute hydrochloric acid remaining on the surfaces of the materials, and finally drying the leftovers in a hot air box for 12 h;

IO 2) crushing and sieving: placing the clean and dry KTN crystal wastes treated in step 1) in a ball milling tank for dry milling for 24 h at a ball-to-material ratio of 2:1 and a rotating speed of 120 r/min; sieving the raw material powder obtained by grinding to obtain raw material powder with a particle size of 270-300 meshes, and repeating step 2) on the remaining materials with a larger particle size; 3) frying wax for granulation: adding paraffin with a mass fraction of 10% into the raw material powder obtained in step 2), placing the mixture in a ceramic evaporating dish, slowly heating the ceramic evaporating dish by using a universal electric stove, and using a medicine spoon to continuously stir to make the raw materials evenly mixed. The heating temperature should not be too high to prevent excessive loss of the paraffin due to excessive heating. The temperature is controlled so that the paraffin just melts. The end point of frying wax is that the paraffin and the raw material are evenly mixed; and after the frying wax is finished, when the paraffin mixture is not yet cooled, performing granulation through an 80-mesh sieve to obtain powder with a uniform particle size; 4) dry pressing: after the granulation is completed, using an electronic balance to weigh an appropriate amount of the mixture, performing cold press molding at a pressure of 40 MPa by using a steel mold, so as to obtain a cylindrical ceramic green body with a diameter of 30 mm, a thickness of 3 mm, a diameter of 10 mm and a height of 5 mm; 5) heating for debinding: placing the ceramic green body on a corundum plate, placing the corundum plate in a high-temperature sintering furnace, heating up to 0-500°C in an air atmosphere at a heating rate of 1°C/min, and keeping the temperature at 500°C for 2 h, so as to -10-

remove the paraffin used as the binder; 6) sintering to form ceramic: after the step of heating for debinding is finished, continuing to heat, heating up to 900°C at a heating rate of 5°C/min, keeping the temperature at 900°C for 1 h, then continuing to heat up to 1170°C at a heating rate of 5°C/min, and keeping the temperature at 1170°C for 2 h; and 7) cooling and sampling: after the above step 0) is finished, cooling at a cooling rate of 5°C/min to room temperature, and taking out the KTN ceramic target material that is sintered at room temperature. The XRD pattern of the obtained product is shown in FIG. 1, and an SEM scanning image is shown in FIG. 2.

The density of the ceramic target material is characterized by the ratio of the actual density of the ceramic target material to the theoretical density, which can be expressed by the formula (1):

Density = (1)

The actual density of the ceramic target material is measured by using the Archimedes drainage method (Archimedes drainage method), the instrument used is an Ohaus FR124CN analytical balance, and the formula (2) used in this process is: mpm

In the above formula, #; represents a dry weight (the mass of the sample in the air), m: represents a floating weight (the mass of the sample in water), and m; represents a wet weight (the weight of the sample after the sample is soaked for 24 h and the distilled water on the surface is wiped), and pg refers to the density of the distilled water (during the measurement, the temperature is recorded, and an instrument appendix is consulted to determine the density of the distilled water).

The density of the KTN crystal is the theoretical density of the KTN ceramic target material.

The XRD pattern shows that the finally obtained KTN ceramic target material has uniform phases, and the density is up to 93%.

Example 2

The difference with the above Example 1 lies in:

The paraffin added in step 3) in Example 1 is replaced with a polyvinyl alcohol solution with a mass fraction of 7 wt%. The raw material powder obtained in step 2) is placed in an agate mortar, -11-

a drop of polyvinyl alcohol solution is added into each gram of material, and grinding is performed for 30 min to uniformly mix the raw material powder with the polyvinyl alcohol binder. After the grinding is finished, granulation is preformed through an 80-mesh sieve.

The debinding temperature of step 5) in Example 1 is changed into 750°C, the heating rate is 2°C/min, and the temperature is kept at 750°C for 2 h to discharge the polyvinyl alcohol used as the binder in the green body.

Finally, a KTN ceramic target material with uniform phases and a density up to 93.5% is obtained. The XRD pattern of the obtained product is shown in FIG. 1.

Example 3

The difference with the above Example 1 lies in:

The raw materials selected in step 1) of Example | are replaced with poorly grown, poor-quality

KTN crystals that do not meet the requirements for use. An appropriate amount of discarded

KTN crystals is taken and is soaked in dilute hydrochloric acid for 3 h, so as to remove the alkaline components in the waste crystals (mainly for the KTN waste crystals with inclusion defects); and then the waste crystals are rinsed with deionized water for 3 times to remove the remaining alcohol and other impurities on the surfaces of the waste crystals, and finally the waste crystals are dried in a hot air box for 12 h; and finally, a KTN ceramic target material with uniform phases and a density up to 93.8% is obtained. The XRD pattern of the obtained product is shown in FIG. 1

The above descriptions are only preferred embodiments of the present invention and are not used for limiting the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modifications, equivalent replacements, improvements and the like, made within the spirit and principle of the present invention, shall all be included in the protection scope of the present invention. -12-

Claims

Claims L A method for preparing a high quality potassium tantalum niobate ceramic target material, comprising: cleaning potassium tantalum niobate crystal waste to obtain a ceramic precursor, crushing and sieving the ceramic precursor to obtain a precursor powder, performing granulation after mixing the precursor powder with a binder, and successively carrying out dry pressing, heating for decomposition and sintering on the granulated powder to obtain the high-quality potassium tantalum niobate ceramic target material, the process of cleaning the potassium tantalum niobate crystal waste includes soaking of the potassium tantalum niobate crystal waste in an acidic solution to remove alkaline components.

The method for preparing the high-quality potassium tantalum niobate ceramic target material according to claim 1, wherein the acidic solution is dilute hydrochloric acid;

The method for preparing the high quality potassium tantalum niobate ceramic target material according to claim 1 or 2, wherein the method of cleaning the potassium tantalum niobate crystal waste comprises: soaking the potassium tantalum niobate crystal waste in acetone.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to claim 1, 2 or 3, wherein the method of cleaning the potassium tantalum niobate crystal waste comprises: soaking the potassium tantalum niobate crystal waste in an alcoholic solution.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein the method for cleaning the potassium tantalum niobate crystal waste comprises washing with water

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein the method -13-

drying the potassium tantalum niobate crystal waste after cleaning it.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein, in the grinding and sieving process, grinding balls are used for grinding and the meal of the grinding balls is 22-26 hours.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein in a ball milling process, the mass ratio of mill balls used for grinding to the ceramic precursor is 2:0.9 to 1.1.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein grinding balls are used for grinding and the grinding balls are agate grinding balls.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein grinding balls are used for grinding and the rotational speed of ball grinding is 100-150 rpm.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein the particle size of the precursor powder is 200-300 mesh.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein the granulation process is as follows: the precursor powder and the binder are heated until the binder is melted, mixed uniformly, and then sieved.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein the pressure of dry pressing is 38-42 MPa.

14. The method of preparing the high quality potassium tantalum niobate ceramic -14-

high quality target material according to any of the preceding claims, wherein in an air atmosphere the temperature is programmed to 500-800°C, and the temperature is maintained.

The method for preparing the high quality potassium tantalum niobate ceramic target material according to any one of the preceding claims, wherein the temperature is programmed to 850-950°C, the temperature is maintained for a set time and, after the temperature is the set time has been maintained, then the temperature is further increased to 1150-1200°C and then the temperature is lowered.

Potassium tantalum niobate ceramic target material, obtained according to the preparation method according to any one of claims 1-15.

Use of the potassium tantalum niobate ceramic target material according to claim 16 as a target material for manufacturing a KTN thin film material.

18. Use of potassium tantalum niobate crystal waste as a raw material for preparing a ceramic target material of potassium tantalum niobate. -15-