Preparation method of nano indium gallium zinc oxide powder with excellent dispersibility

Abstract

The embodiment of the invention discloses a preparation method of nano indium gallium zinc oxide powder with excellent dispersibility, which comprises the following steps: dropwise adding a precipitant consisting of ammonia water and an ammonium bicarbonate solution into a reactant mixed solution, stirring the reactant mixed solution to carry out primary precipitation reaction at the temperature of 40-60 DEG C and the stirring speed of 300-500rpm / min, and stopping dropwise adding the precipitant when the pH value reaches 3.2-4.8; continuously dropwise adding the precipitator at the temperature of 60-80 DEG C and the stirring speed of 500-700rpm / min to carry out secondary precipitation reaction until the pH value of the mixed solution reaches 5.4-6.5; continuously dropwise adding the precipitant to carry out a third precipitation reaction under the conditions that the temperature is controlled to be 60-80 DEG C and the stirring speed is controlled to be 700-1000 rpm / min, and stopping dropwise adding the precipitant when the pH value reaches 7.8-8.3; keeping the pH value of the solution at 7.8-8.3, carrying out a fourth precipitation reaction, and continuously stirring for 2-4 hours until no bubble is generated; carrying out aging treatment on the mixed solution to obtain a white precipitate; carrying out drying treatment on the white precipitate to obtain precursor powder; and carrying out high-temperature calcination treatment on the precursor powder to obtain the nano indium gallium zinc oxide powder with excellent dispersibility.

Description

Technical Field

[0001] The invention belongs to the technical field of powder materials, and in particular relates to a method for preparing highly dispersed nano-indium gallium zinc oxide powder. Background Art

[0002] In the next generation of displays, metal oxide semiconductors (MOS) have been widely used in optically transparent electronic components. The most promising oxide film developed recently is amorphous IGZO (α-IGZO) film. Based on the performance of IGZO-TFT, which has higher electron mobility and lower off-current than traditional α-Si devices, it has shown great development potential in emerging display fields such as flexible display. α-Si TFT belongs to the traditional TFT-LCD display technology, while IGZO-TFT belongs to the new generation of display technology. Indium gallium zinc oxide powder is the basic raw material of indium gallium zinc oxide target. The quality of its powder purity, particle size, dispersibility and other parameters will seriously affect the performance of the target, thereby restricting the subsequent coating process and film quality.

[0003] Among the preparation methods of indium gallium zinc oxide (IGZO) powder, the chemical precipitation method uses cheap inorganic raw materials, simple equipment, and has unparalleled advantages over other methods in terms of powder activity, so the chemical precipitation method has become the most commonly used powder preparation method. However, the chemical precipitation method has natural defects: in the liquid phase precipitation process, the grain size is very small and has extremely high surface energy; there are many defects on the surface of the grains, and there are a large number of dangling bonds and unsaturated bonds, which make the particles charged, resulting in high free energy and a tendency to agglomerate; and when two solutions are mixed, there will always be an uneven mixing concentration. At this time, the area that contacts first or the area with high concentration will generate nuclei and grow first, and after nucleation in the area that contacts later or has low concentration, the fine particles will naturally adsorb on the large particles generated first, thus forming agglomerates; once agglomerates are formed during the precipitation process, they will continue to exist in their natural state and be inherited throughout the powder preparation process until the final powder is prepared; and the agglomerated powder will produce low density and poor uniformity in the process of preparing the sputtering target green body, which will seriously affect the sputtering performance of the target material, and high-performance TCO films cannot be obtained, which cannot meet the requirements of high-end flat panel displays. Summary of the invention

[0004] In view of this, some embodiments disclose a method for preparing nano-indium gallium zinc oxide powder with excellent dispersion, comprising the steps of:

[0005] S1, adding a precipitant dropwise to the reactant mixed solution, stirring the reactant mixed solution for the first precipitation reaction, when the pH value of the reactant mixed solution reaches 3.2-4.8, stopping the addition of the precipitant, and continuing stirring for a set time; wherein the precipitant is a solution comprising ammonia water and ammonium bicarbonate, the reactant mixed solution is a nitric acid solution comprising indium ions, gallium ions and zinc ions, the temperature of the reactant mixed solution is controlled at 40-60°C, the stirring speed is controlled at 300-500rpm / min, and the dropping speed of the precipitant is controlled at 3-5ml / min; during the first precipitation reaction, gallium hydroxide precipitate is gradually generated, the gallium hydroxide precipitate is gradually agglomerated into precipitate particles, and the bubbles formed by the heating and decomposition of ammonium bicarbonate impact the precipitate particles in the reactant mixed solution to control the size to be in the nanometer scale;

[0006] S2, the temperature of the reactant mixed solution is controlled at 60-80°C, the stirring speed is controlled at 500-700rpm / min, the precipitant is continuously added to the reactant mixed solution, and a second precipitation reaction is performed, the dropping speed of the precipitant is controlled at 3-5ml / min, and when the pH value of the reactant mixed solution reaches 5.4-6.5, the dropping of the precipitant is stopped, and the stirring is continued for a set time; wherein, during the second precipitation reaction, gallium hydroxide precipitate is continuously generated, and at the same time, indium hydroxide precipitate is gradually generated, and the generated precipitate gradually agglomerates into precipitate particles, and the bubbles formed by the heating and decomposition of ammonium bicarbonate impact the precipitate particles in the reactant mixed solution to control the size to be in the nanometer scale;

[0007] S3, the temperature of the reactant mixed solution is controlled at 60-80°C, the stirring speed is controlled at 700-1000rpm / min, the precipitant is continuously added dropwise to the reactant mixed solution, and a third precipitation reaction is performed, the precipitant addition speed is controlled at 1-2ml / min, and when the pH value of the reactant mixed solution reaches 7.8-8.3, the precipitant is stopped from being added dropwise, and the stirring is continued for a set time; wherein, during the third precipitation reaction, zinc hydroxide precipitate is gradually generated and agglomerated into precipitate particles, and the bubbles formed by the heating and decomposition of ammonium bicarbonate impact the precipitate particles in the reactant mixed solution to control the size to be in the nanometer scale;

[0008] S4, stop adding the precipitant, control the temperature of the reactant mixed solution at 20-30°C, control the stirring speed at 200-400rpm / min, maintain the pH value of the solution at 7.8-8.3, carry out the fourth precipitation reaction, and continue stirring for 2-4h until no bubbles are generated; wherein, during the fourth precipitation reaction, the precipitated particles that have been generated are further homogenized and suspended in the reactant mixed solution;

[0009] S5, the reactant mixed solution obtained in step S4 is subjected to aging treatment to obtain a white precipitate;

[0010] S6, drying the white precipitate to obtain a precursor powder;

[0011] S7. The precursor powder is calcined to obtain nano-indium gallium zinc oxide powder with excellent dispersion.

[0012] Furthermore, in some embodiments of the method for preparing highly dispersed nano-indium gallium zinc oxide powder, the concentrations of ammonia water and ammonium bicarbonate in the precipitant are both 0.5-1 mol / L, and the volume ratio of ammonia water to ammonium bicarbonate solution is controlled between 10 and 20:1.

[0013] Some embodiments disclose a method for preparing a highly dispersed nano-indium gallium zinc oxide powder, and a method for preparing a precipitant, comprising:

[0014] According to the set ratio, ammonia water and ammonium bicarbonate solution are evenly mixed in a glass beaker and fully mixed by magnetic stirring; wherein, the heating temperature of the magnetic stirrer is set to 20-30°C, the speed of the magnetic stirrer is set to 200-300rpm / min, and maintained for 10-20min, and the precipitant preparation is completed.

[0015] In the method for preparing the highly dispersed nano-indium gallium zinc oxide powder disclosed in some embodiments, the concentrations of indium ions, gallium ions and zinc ions in the reactant mixed solution are all controlled between 0.05 and 0.5 mol / L.

[0016] Some embodiments disclose a method for preparing a highly dispersed nano-indium gallium zinc oxide powder, and a method for preparing a mixed solution of reactants, including:

[0017] Mix metal indium particles, gallium particles and zinc particles, put them into a polytetrafluoroethylene beaker, and place it on a magnetic stirrer; the heating temperature of the magnetic stirrer is set to 20-30°C, and the speed is set to 300-500rpm / min;

[0018] Adding an appropriate amount of nitric acid to dissolve the indium particles, gallium particles and zinc particles to obtain a uniform mixed solution of indium nitrate, gallium nitrate and zinc nitrate; wherein the mass volume concentration of the nitric acid is 50-65%;

[0019] The uniformly mixed solution was transferred to a volumetric flask through filter paper and fixed to volume to obtain a reactant mixed solution with a set concentration.

[0020] In the method for preparing highly dispersed nano-indium gallium zinc oxide powder disclosed in some embodiments, in step S5, the temperature of the reactant mixed solution for aging treatment is 20 to 40° C., and the aging time is controlled to be 24 to 48 hours.

[0021] In some embodiments of the method for preparing highly dispersed nano-indium gallium zinc oxide powder, in step S6, the temperature for drying the white precipitate is 60 to 90° C., and the drying time is controlled to be 24 to 36 hours.

[0022] Some embodiments disclose a method for preparing highly dispersed nano-indium gallium zinc oxide powder. In step S7, the temperature of the precursor powder for calcining is 800-1200°C, the heating rate is set to 3°C / min, and the holding time is 2-8h; the cooling rate is set to 3°C / min, and the temperature is cooled to 20-30°C.

[0023] In some embodiments, the method for preparing the highly dispersed nano-indium gallium zinc oxide powder disclosed in the embodiment further comprises washing the obtained white precipitate in step S5, which specifically comprises:

[0024] The white precipitate was placed in a centrifuge and washed by centrifugation multiple times with pure water and anhydrous ethanol. The speed of the centrifuge was 4000-5500 rpm / min.

[0025] In some embodiments of the method for preparing nano-indium gallium zinc oxide powder with excellent dispersion, in step S7, the precursor powder is ground before calcination, and the ground precursor powder is sieved with a 200-mesh screen.

[0026] The method for preparing nano-indium gallium zinc oxide powder with good dispersion disclosed in the embodiment of the present invention utilizes bubbles generated by the decomposition of ammonium bicarbonate to stir a reactant mixed solution, impact the generated precipitation particles, and decompose them into precipitation particles with smaller sizes, which can effectively control the particle diameter and prevent them from growing; the precipitation particles with smaller diameters can further serve as new nucleation centers, and the subsequently generated precipitations are deposited and grown on the nucleation centers, and effective control of the precipitation particle diameter is achieved during the continuous reaction process; at the same time, good control of the pH value of the reactant mixed solution is achieved by controlling the synergistic effect of ammonia water and ammonium bicarbonate, and the gradual precipitation of gallium ions, indium ions and zinc ions is achieved by controlling the pH value of the reactant mixed solution and the stirring speed, and finally the uniform and complete precipitation of the three ions is achieved; and then the nano-indium gallium zinc oxide powder with good dispersion is obtained through drying and calcination treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the SEM image of the well-dispersed nano-IGZO powder obtained in Example 1;

[0028] Figure 2 This is the SEM image of the IGZO powder obtained in Comparative Example 1. DETAILED DESCRIPTION

[0029] The word "embodiment" used herein as an "exemplary" does not necessarily mean that any embodiment described is superior or better than other embodiments. Performance index tests in the embodiments of the present invention are performed using conventional test methods in the art unless otherwise specified. It should be understood that the terms described in the embodiments of the present invention are only used to describe specific implementation methods and are not intended to limit the contents disclosed in the embodiments of the present invention.

[0030] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by ordinary technicians in the technical field to which the embodiments of the present invention belong; other experimental methods and technical means not specifically specified in the embodiments of the present invention refer to experimental methods and technical means commonly used by ordinary technicians in the field.

[0031] The terms "substantially" and "approximately" used herein are used to describe small fluctuations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. The numerical data represented or presented in the range format herein are used only for convenience and brevity, and should therefore be flexibly interpreted as including not only the values ​​clearly listed as the limits of the range, but also all independent values ​​or sub-ranges contained in the range. For example, the numerical range of "1-5%" should be interpreted as including not only the clearly listed values ​​of 1% to 5%, but also the independent values ​​and sub-ranges within the range shown. Therefore, independent values ​​such as 2%, 3.5% and 4% and sub-ranges such as 1%-3%, 2%-4% and 3%-5% are included in this numerical range. This principle also applies to the range of only one numerical value. In addition, such an interpretation applies regardless of the width of the range or the characteristics described.

[0032] In this document, including in the claims, transitional words such as "comprises," "includes," "with," "having," "containing," "involving," "accommodating," etc. are understood to be open-ended, i.e., meaning "including but not limited to." Only the transitional words "consisting of" and "composed of" are closed transitional words.

[0033] In order to better illustrate the present invention, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the gist of the present invention.

[0034] Under the premise of no conflict, the technical features disclosed in the embodiments of the present invention may be arbitrarily combined, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present invention.

[0035] In some embodiments, the method for preparing highly dispersed nano-indium gallium zinc oxide powder comprises the steps of:

[0036] S1, adding a precipitant dropwise to the reactant mixed solution, stirring the reactant mixed solution to perform a first precipitation reaction, when the pH value of the reactant mixed solution reaches 3.2-4.8, stopping the addition of the precipitant, and continuing stirring for a set time; wherein the precipitant is a solution comprising ammonia water and ammonium bicarbonate, the reactant mixed solution is a nitric acid solution comprising indium ions, gallium ions, and zinc ions, the temperature of the reactant mixed solution is controlled at 40-60°C, the stirring speed is controlled at 300-500rpm / min, and the dropping speed of the precipitant is controlled at 3-5ml / min; during the first precipitation reaction, gallium hydroxide precipitate is gradually generated, the gallium hydroxide precipitate gradually agglomerates into precipitate particles, and the bubbles formed by the heating and decomposition of ammonium bicarbonate impact the precipitate particles in the reactant mixed solution to control the size to be in the nanometer scale;

[0037] The first precipitation reaction stage is the initial stage of the reaction. With the addition of the precipitant, a large number of uniform fine bubbles are generated in the mixed solution of the reactants. The continuous generation of sufficient bubbles has an orderly impact on the few generated precipitation particle agglomerates to prevent the precipitation particles from agglomerating. At the same time, the pH value of the mixed solution monitored during the precipitation reaction is measured and recorded. When the pH value of the solution reaches 3.2-4.8, the addition of the precipitant is stopped, and the solution is stirred for 10-20 minutes to allow the gallium ions in the mixed solution to precipitate first. Usually, this stage is the initial stage of the formation of precipitation particles, mainly the generation of gallium hydroxide precipitation. At this time, the number of particles in the solution for the nucleation and growth of precipitation particles is small. The water bath temperature is set at 40-60°C and the magnetic stirring speed is set at 300-500rpm / min to control the number of bubbles generated to prevent the precipitation particles from agglomerating.

[0038] In some embodiments, the concentrations of ammonia water and ammonium bicarbonate in the precipitant are both 0.5-1 mol / L, and the volume ratio of ammonia water to ammonium bicarbonate solution is controlled between 10 and 20:1; generally, ammonia water has a strong alkalinity, and after reacting and decomposing in a metal salt solution, it can provide sufficient hydroxide ions for the precipitation reaction of metal ions. Ammonium bicarbonate decomposes at high temperature to form sufficient bubbles of uniform size, which have an impact on the precipitated particles produced by the precipitation reaction, and can decompose the particles into smaller particles, which is conducive to the control of the precipitated particles and improves their uniformity and dispersibility.

[0039] In some embodiments, the preparation method of the precipitant includes: uniformly mixing ammonia water and ammonium bicarbonate solution in a glass beaker according to a set ratio, and stirring the mixture magnetically for thorough mixing; wherein the heating temperature of the magnetic stirrer is set to 20-30° C., the speed of the magnetic stirrer is set to 200-300 rpm / min, and the stirring is maintained for 10-20 minutes to obtain the precipitant;

[0040] In some embodiments, the concentrations of indium ions, gallium ions, and zinc ions in the reactant mixed solution are all controlled between 0.05 and 0.5 mol / L;

[0041] In some embodiments, in order to achieve the preparation of nano-indium gallium zinc oxide powder with excellent dispersion, high-purity metal indium particles (purity of 4N), high-purity metal gallium particles (purity of 4N), and high-purity metal zinc particles (purity of 4N) are preferably used, and nitric acid is selected as an inorganic acid reagent to dissolve metal indium, gallium, and zinc to obtain In 3+ , Ga 3+ 、Zn 2+ The mixed salt solution is prepared by controlling the mass volume concentration of the nitric acid solution to be within the range of 50 to 65%. The preparation method of the mixed solution of the reactants comprises:

[0042] Mix metal indium particles, gallium particles and zinc particles, put them into a polytetrafluoroethylene beaker, and place it on a magnetic stirrer; the heating temperature of the magnetic stirrer is set to 20-30°C, and the speed is set to 300-500rpm / min;

[0043] Adding an appropriate amount of nitric acid to dissolve the indium particles, gallium particles and zinc particles to obtain a uniform mixed solution of indium nitrate, gallium nitrate and zinc nitrate; wherein the mass volume concentration of the nitric acid is 50-65%;

[0044] The uniformly mixed solution is transferred to a volumetric flask through filter paper to be fixed to volume, thereby obtaining a reactant mixed solution with a set concentration;

[0045] S2, the temperature of the reactant mixed solution is controlled at 60-80°C, the stirring speed is controlled at 500-700rpm / min, the precipitant is continuously added to the reactant mixed solution, and a second precipitation reaction is performed, the dropping speed of the precipitant is controlled at 3-5ml / min, and when the pH value of the reactant mixed solution reaches 5.4-6.5, the dropping of the precipitant is stopped, and the stirring is continued for a set time; wherein, during the second precipitation reaction, gallium hydroxide precipitate is continuously generated, and at the same time, indium hydroxide precipitate is gradually generated, and the generated precipitate gradually agglomerates into precipitate particles, and the bubbles formed by the heating and decomposition of ammonium bicarbonate impact the precipitate particles in the reactant mixed solution to control the size to be in the nanometer scale;

[0046] In the second precipitation reaction stage, the number of precipitated particles generated in the mixed solution increases rapidly. In addition to the gallium hydroxide precipitation, indium ions are easily combined with hydroxide in the precipitant to form indium hydroxide precipitated particles, and gel agglomerates are easily formed in the mixed solution. However, due to the adjustment of the water bath temperature and the stirring speed, the number of bubbles generated by the decomposition of ammonium bicarbonate in the precipitant increases, and the bubble impact capacity is improved, which can effectively hinder the agglomeration of precipitated particles. When the pH value of the solution reaches 5.4-6.5, the addition of the precipitant is stopped, and the stirring in the solution is continued. The solution is kept reacting for 10-20 minutes.

[0047] S3, the temperature of the reactant mixed solution is controlled at 60-80°C, the stirring speed is controlled at 700-1000rpm / min, the precipitant is continuously added dropwise to the reactant mixed solution, and a third precipitation reaction is performed, the precipitant addition speed is controlled at 1-2ml / min, and when the pH value of the reactant mixed solution reaches 7.8-8.3, the precipitant is stopped from being added dropwise, and the stirring is continued for a set time; wherein, during the third precipitation reaction, zinc hydroxide precipitate is gradually generated and agglomerated into precipitate particles, and the bubbles formed by the heating and decomposition of ammonium bicarbonate impact the precipitate particles in the reactant mixed solution to control the size to be in the nanometer scale;

[0048] In the third precipitation reaction stage, the precipitant is continued to be added to the mixed solution of the reactants, the temperature of the mixed solution is maintained at 60-80°C, the stirring speed is adjusted to 700-1000rpm / min, the bubble generation rate is maintained while the stirring speed is increased to break up the larger bubbles that have been generated, so that the bubble volume is small and uniform, and the number of bubbles is doubled; at this stage, the gallium ions and indium ions have been precipitated, and the solution is mainly zinc ions. The main precipitation reaction in this stage is that the zinc ions collide with the hydroxide in the mixed solution of the reactants to generate zinc hydroxide precipitation particles; due to the presence of many uniform and tiny bubbles, with the increase of the stirring rate, the agglomeration of the zinc hydroxide precipitation particles in the solution is significantly weakened, thereby avoiding the formation of large-sized particles, so that the entire mixed solution reaction system remains uniform and stable; at the same time, the precipitant drop rate is adjusted to 1-2ml / min to slow down the precipitation reaction until the pH value of the solution reaches 7.8-8.3, and the stirring is continued for 1-2h to complete the precipitation of zinc ions in the mixed metal salt solution;

[0049] S4, stop adding the precipitant, control the temperature of the reactant mixed solution at 20-30°C, control the stirring speed at 200-400rpm / min, maintain the pH value of the solution at 7.8-8.3, carry out the fourth precipitation reaction, and continue stirring for 2-4h until no bubbles are generated; wherein, during the fourth precipitation reaction, the precipitated particles that have been generated are further homogenized and suspended in the reactant mixed solution;

[0050] In the fourth precipitation reaction stage, the water bath temperature is lowered to reduce the driving force for the growth of precursor particles, and continuous stirring is to ensure that the precipitation reaction proceeds fully while inhibiting the growth of precursor particles. Stirring is continued until no obvious bubbles are generated in the mixed solution reaction system, the precipitation particles are evenly suspended in the solution, and the precipitation process is basically completed.

[0051] S5, the reactant mixed solution obtained in step S4 is subjected to aging treatment to obtain a white precipitate;

[0052] Usually, the product obtained by precipitation is in the form of milky white slurry. The beaker is sealed with plastic wrap to prevent dust from falling into the air, and then aging treatment is performed; the aging temperature is controlled at 20-40°C, and the aging time is controlled at 24-48h; after the aging process is completed, the supernatant is poured out, leaving the white precipitate, which is placed in a centrifuge and washed with pure water and anhydrous ethanol for multiple times, and the centrifuge speed is 4000-5500rpm / min to remove impurity ions;

[0053] S6, drying the white precipitate to obtain a precursor powder;

[0054] Usually, the white precipitate obtained after washing can be transferred to a constant temperature drying oven for drying, the drying temperature is set at 60-90°C, and the drying time is controlled at 24-36h;

[0055] S7. The precursor powder is calcined to obtain nano-indium gallium zinc oxide powder with excellent dispersion.

[0056] Take out the dried precursor powder, transfer it to a mortar for grinding, and sieve it with a 200-mesh screen. Put the sieved precursor into an alumina crucible and place it in a muffle furnace. Set the heating rate to 3°C / min, the heating end point to 800-1200°C, the holding time to 2-8h, the cooling rate to 3°C / min, cool to 20-30°C, take out the calcined powder, and obtain IGZO powder.

[0057] The method for preparing nano-indium gallium zinc powder with excellent dispersion disclosed in the embodiment of the present invention does not require any additional auxiliary equipment. By utilizing the property of ammonium bicarbonate that ammonium bicarbonate is easily decomposed at high temperature, the ammonium bicarbonate is rapidly decomposed in the reactant mixed solution to generate carbon dioxide and ammonia through water bath heating and accelerated stirring during the precipitation reaction. The carbon dioxide is not easy to escape from the mixed solution, and a large number of uniform bubbles are formed and stably exist in the reactant mixed solution. The accelerated stirring of the reactant mixed solution helps to impact the formed larger particle precipitate and decompose it into smaller dispersed particles, so that the smaller dispersed particles can be used as new nucleation points to generate precipitation particles. The problem of powder agglomeration in the process of producing IGZO powder by the liquid phase method is effectively solved. Since the reactant mixed solution reaction system itself generates bubbles to disperse the nucleation particles and make them uniform, the dispersion uniformity and particle size distribution of the powder are also improved; the ammonia gas produced by the decomposition of ammonium bicarbonate dissolves in the reaction solution to provide some hydroxide ions, which work together with ammonia water to help quickly establish an alkaline environment and ensure the precipitation reaction; in addition, the precipitation process can ensure that the three metal ions of gallium ions, indium ions and zinc ions in the solution are fully mixed and uniformly precipitated by precisely controlling the precipitation reaction pH value and reaction time; the gallium ions, indium ions and zinc ions are precipitated separately in a certain order, so that the three metal ions maintain the corresponding precipitation reaction time period within their respective precipitation pH ranges, and then precipitate completely.

[0058] The method for preparing well-dispersed nano-indium gallium zinc powder disclosed in the embodiment of the present invention realizes the synergistic effect of the precipitation process and the bubble impact by combining the metal ion precipitation process and the bubble impact, solves the agglomeration problem of nano-powders prepared by the liquid phase method, realizes the preparation of well-dispersed nano-indium gallium zinc oxide powder, and obtains high-performance IGZO powder.

[0059] The technical details are further illustrated below in conjunction with embodiments.

[0060] Example 1

[0061] The method for preparing the highly dispersed nano-indium gallium zinc powder disclosed in Example 1 comprises:

[0062] S1. Select high-purity metal indium particles (4N), high-purity metal gallium particles (4N), and high-purity metal zinc particles (4N) and place them in a polytetrafluoroethylene beaker, place them on a magnetic stirrer, set the temperature to 25°C, and the speed to 400rpm / min. Select a nitric acid solution with a concentration of 65% and add it to the beaker to dissolve high-purity metal indium, gallium, and zinc to obtain In 3+ , Ga 3+ 、Zn 2+ The reactant mixture was mixed and the dissolved In[(NO) 3 ] 3,Ga[(NO) 3 ] 3 、Zn[(NO) 3 ] 2 The mixed solution was transferred to a volumetric flask through filter paper and fixed to volume. 3+ , Ga 3+ 、Zn 2+ The concentration is 0.1 mol / L, In 3+ , Ga 3+ 、Zn 2+ The molar ratio of is 1:1:1, as the reactant mixture;

[0063] According to the ratio of 10:1, the corresponding amount of ammonia water and ammonium bicarbonate solution were measured, and the two were evenly mixed and placed in a glass beaker. The magnetic stirrer was set at 25°C and the speed was set at 300 rpm / min for 20 minutes to fully mix, and a mixed solution of ammonia water and ammonium bicarbonate was obtained as a precipitant, wherein the concentrations of ammonia water and ammonium bicarbonate solution were both controlled to be 1 mol / L;

[0064] The precipitant is added dropwise to the reactant mixed solution through a constant pressure dropping funnel, and the reactant mixed solution is stirred to perform the first precipitation reaction. When the pH value of the reactant mixed solution reaches 3.8, the addition of the precipitant is stopped, and the stirring is continued for 20 minutes; wherein the precipitant is a solution containing ammonia water and ammonium bicarbonate, the reactant mixed solution is a nitrate solution containing indium ions, gallium ions, and zinc ions, the temperature of the reactant mixed solution is controlled at 40°C, the stirring speed is controlled at 500rpm / min, and the dropping speed of the precipitant is controlled at 3ml / min;

[0065] S2, the temperature of the reactant mixed solution is controlled at 60 ° C, the stirring speed is controlled at 700 rpm / min, and the precipitant is continued to be added to the reactant mixed solution to perform a second precipitation reaction. The dropping speed of the precipitant is controlled to 3 ml / min. When the pH value of the reactant mixed solution reaches 5.5, the dropping of the precipitant is stopped and stirring is continued for 20 min;

[0066] S3, the temperature of the reactant mixed solution is controlled at 60 ° C, the stirring speed is controlled at 1000 rpm / min, and the precipitant is continued to be added dropwise to the reactant mixed solution to perform a third precipitation reaction. The dropping speed of the precipitant is controlled to be 1 ml / min. When the pH value of the reactant mixed solution reaches 8.0, the dropping of the precipitant is stopped and the stirring is continued;

[0067] S4, stop adding the precipitant, control the temperature of the mixed solution of the reactants at 25°C, control the stirring speed at 400 rpm / min, maintain the pH value of the solution at 8.0, perform the fourth precipitation reaction, and continue stirring for 4 hours until no bubbles are generated;

[0068] S5. The mixed solution of the reactants obtained in step S4 is sealed in a beaker with a plastic wrap to prevent dust from falling into the air, and then aged; the aging temperature is controlled at 25° C., and the aging time is controlled at 48 h. After the aging process is completed, the supernatant is poured out, leaving the white precipitate, which is placed in a centrifuge and washed with pure water and anhydrous ethanol for multiple times, and the centrifuge speed is 4000 rpm / min to remove impurity ions;

[0069] S6. After washing, the precipitate is transferred to a constant temperature drying oven for drying. The drying temperature is set to 80° C. and the drying time is controlled at 36 h to obtain a dried precursor powder.

[0070] S7. Take out the precursor powder after drying, transfer it to a mortar for grinding, and sieve it with a 200-mesh sieve; put the sieved precursor into an alumina crucible and place it in a muffle furnace, set the heating rate to 3°C / min, heat it to 1200°C, keep it warm for 6 hours, set the cooling rate to 3°C / min, cool it to 25°C, and obtain nano-indium gallium zinc oxide powder with excellent dispersion.

[0071] The scanning electron microscope image of the nano IGZO powder obtained in this Example 1 is as follows Figure 1 As shown, it can be seen that the IGZO grain size is uniform and the dispersion is good, and the agglomeration phenomenon is greatly improved. It can be seen that Example 1 obtains nano-indium gallium zinc oxide powder with excellent dispersion.

[0072] Example 2

[0073] The preparation method of the well-dispersed nano-indium gallium zinc powder disclosed in Example 2 refers to Example 1; wherein, corresponding amounts of ammonia water and ammonium bicarbonate solution are measured in a ratio of 20:1, the two are evenly mixed and placed in a glass beaker, the magnetic stirrer is set to 25°C and the speed is set to 300 rpm / min for 20 minutes for sufficient mixing to obtain a mixed solution of ammonia water and ammonium bicarbonate as a precipitant, wherein the concentrations of ammonia water and ammonium bicarbonate solution are both controlled to 1 mol / L.

[0074] The IGZO powder obtained in Example 2 has uniform grain size and good dispersibility, and nano-indium gallium zinc oxide powder with excellent dispersibility is obtained, and the agglomeration phenomenon is greatly improved.

[0075] Example 3

[0076] The method for preparing the nano-indium gallium zinc powder with excellent dispersion disclosed in Example 3 is as described in Example 1; wherein, in the reactant mixture, In 3+ , Ga 3+ 、Zn 2+ The concentrations were 0.1mol / L, 0.1mol / L, and 0.2mol / L, respectively. 3+ , Ga3+ 、Zn 2+ The molar ratio is 1:1:2.

[0077] The IGZO powder obtained in Example 3 has uniform grain size and good dispersibility, and nano-indium gallium zinc oxide powder with excellent dispersibility is obtained, and the agglomeration phenomenon is greatly improved.

[0078] Comparative Example 1

[0079] Comparative Example 1 discloses a preparation process of indium gallium zinc oxide powder particles, which specifically includes:

[0080] Step 1: Use nitric acid with a solution concentration of 65% as an inorganic acid reagent to dissolve high-purity metal indium (4N), gallium (4N), and zinc (4N) to obtain In[(NO) 3 ] 3 ,Ga[(NO) 3 ] 3 、Zn[(NO) 3 ] 2 A uniform mixture of three metal salts to control In 3+ , Ga 3+ 、Zn 2+ The concentration of the three ions is 0.1 mol / L; concentrated ammonia water containing 25% ammonia is selected as the reaction precipitant;

[0081] Step 2: Put metal indium particles, gallium particles and zinc particles into a polytetrafluoroethylene beaker and place it on a magnetic stirrer. Set the temperature to 25°C and the magnetic speed to 400 rpm / min. Add a slightly excessive amount of nitric acid to dissolve the indium particles, gallium particles and zinc particles. Use the chrysanthemum-shaped folded filter paper method to remove the dissolved In[(NO) 3 ] 3 ,Ga[(NO) 3 ] 3 、Zn[(NO) 3 ] 2 The uniform mixed solution of the three metal salts was transferred to a volumetric flask through filter paper for constant volume;

[0082] Step 3: Transfer the mixed metal salt solution to a beaker, and then add ammonia water to the In[(NO) 3 ] 3 ,Ga[(NO) 3 ] 3 、Zn[(NO) 3 ] 2The three metal salts were reacted in a mixed solution, the dropping speed was adjusted to 3 ml / min, the magnetic stirring speed was 400 rpm / min, and when the pH value of the solution reached 8.0, the addition of the precipitant was stopped, and the solution was stirred for 30 min to allow the three metal ions in the salt solution to precipitate;

[0083] Step 4: Take out the milky white precursor slurry after precipitation, cover it with plastic wrap and then age it. The aging temperature is controlled at 25°C and the aging time is controlled at 48h. After aging, centrifuge and wash to remove impurity ions. Transfer it to a constant temperature drying oven for drying. The drying temperature is set to 80°C and the drying time is controlled at 36h. Take out the dried precursor powder and grind and sieve it.

[0084] Step 5: calcine the precursor powder obtained by screening at high temperature, set the heating rate to 3°C / min, heat to 1200°C, keep warm for 6 hours, and then cool to room temperature at a cooling rate of 3°C / min. After the calcination is completed, IGZO powder is obtained.

[0085] The scanning electron microscope image of the IGZO powder prepared in Comparative Example 1 is as follows: Figure 2 As shown by Figure 2 It can be seen that the powder agglomeration phenomenon is serious, the dispersibility is poor, the grain sizes are different, and the indium gallium zinc oxide powder with good dispersibility is not obtained.

[0086] The method for preparing nano-indium gallium zinc oxide powder with good dispersion disclosed in the embodiment of the present invention utilizes bubbles generated by the decomposition of ammonium bicarbonate to stir a reactant mixed solution, impact the generated precipitation particles, and decompose them into precipitation particles with smaller sizes, which can effectively control the particle diameter and prevent them from growing; the precipitation particles with smaller diameters can further serve as new nucleation centers, and the subsequently generated precipitations are deposited and grown on the nucleation centers, and effective control of the precipitation particle diameter is achieved during the continuous reaction process; at the same time, good control of the pH value of the reactant mixed solution is achieved by controlling the synergistic effect of ammonia water and ammonium bicarbonate, and the gradual precipitation of gallium ions, indium ions and zinc ions is achieved by controlling the pH value of the reactant mixed solution and the stirring speed, and finally the uniform and complete precipitation of the three ions is achieved; and then the nano-indium gallium zinc oxide powder with good dispersion is obtained through drying and calcination treatment.

[0087] The technical solutions disclosed in the embodiments of the present invention and the technical details disclosed in the embodiments are merely illustrative of the inventive concept of the present invention and do not constitute a limitation on the technical solutions of the embodiments of the present invention. Any conventional changes, replacements or combinations of the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention and are within the protection scope of the claims of the present invention.

Claims

1. A method for preparing nano-indium gallium zinc oxide powder with excellent dispersion, characterized in that: Includes steps: S1, adding a precipitant dropwise to the reactant mixed solution, stirring the reactant mixed solution for the first precipitation reaction, when the pH value of the reactant mixed solution reaches 3.2-4.8, stopping the addition of the precipitant, and continuing stirring for a set time; wherein the precipitant is a solution comprising ammonia water and ammonium bicarbonate, the reactant mixed solution is a nitric acid solution comprising indium ions, gallium ions and zinc ions, the temperature of the reactant mixed solution is controlled at 40-60°C, the stirring speed is controlled at 300-500rpm / min, and the dropping speed of the precipitant is controlled at 3-5ml / min; during the first precipitation reaction, gallium hydroxide precipitate is gradually generated, the gallium hydroxide precipitate is gradually agglomerated into precipitate particles, and the bubbles formed by the heating and decomposition of ammonium bicarbonate impact the precipitate particles in the reactant mixed solution to control the size to be in the nanometer scale; S2, the temperature of the reactant mixed solution is controlled at 60-80°C, the stirring speed is controlled at 500-700rpm / min, the precipitant is continuously added to the reactant mixed solution, and a second precipitation reaction is performed, the dropping speed of the precipitant is controlled at 3-5ml / min, and when the pH value of the reactant mixed solution reaches 5.4-6.5, the dropping of the precipitant is stopped, and the stirring is continued for a set time; wherein, during the second precipitation reaction, gallium hydroxide precipitate is continuously generated, and at the same time, indium hydroxide precipitate is gradually generated, and the generated precipitate gradually agglomerates into precipitate particles, and the bubbles formed by the heating and decomposition of ammonium bicarbonate impact the precipitate particles in the reactant mixed solution to control the size to be in the nanometer scale; S3, the temperature of the reactant mixed solution is controlled at 60-80°C, the stirring speed is controlled at 700-1000rpm / min, the precipitant is continuously added to the reactant mixed solution, and the third precipitation reaction is performed, the dropping speed of the precipitant is controlled at 1-2ml / min, and when the pH value of the reactant mixed solution reaches 7.8-8.3, the dropping of the precipitant is stopped, and the stirring is continued for a set time; wherein, during the third precipitation reaction, zinc hydroxide precipitate is gradually generated and agglomerated into precipitate particles, and the bubbles formed by the heating and decomposition of ammonium bicarbonate impact the precipitate particles to control the size to be in the nanometer scale; S4, stop adding the precipitant, control the temperature of the reactant mixed solution at 20-30°C, control the stirring speed at 200-400rpm / min, maintain the pH value of the solution at 7.8-8.3, carry out the fourth precipitation reaction, and continue stirring for 2-4h until no bubbles are generated; wherein, during the fourth precipitation reaction, the precipitated particles that have been generated are further homogenized and suspended in the reactant mixed solution; S5, the mixed solution of the reactants obtained in step S4 is subjected to aging treatment to obtain a white precipitate; S6, drying the white precipitate to obtain a precursor powder; S7. The precursor powder is calcined to obtain nano-indium gallium zinc oxide powder with excellent dispersion.

2. The method for preparing highly dispersed nano-indium gallium zinc oxide powder according to claim 1, characterized in that: The concentrations of ammonia water and ammonium bicarbonate in the precipitant are both 0.5-1 mol / L, and the volume ratio of ammonia water to ammonium bicarbonate solution is controlled between 10-20:

1.

3. The method for preparing highly dispersed nano-indium gallium zinc oxide powder according to claim 2, characterized in that: The preparation method of the precipitant comprises: According to the set ratio, ammonia water and ammonium bicarbonate solution are evenly mixed in a glass beaker and fully mixed by magnetic stirring; wherein, the heating temperature of the magnetic stirrer is set to 20-30°C, the speed of the magnetic stirrer is set to 200-300rpm / min, and maintained for 10-20min, and the precipitant preparation is completed.

4. The method for preparing highly dispersed nano-indium gallium zinc oxide powder according to claim 1, characterized in that: In the reactant mixed solution, the concentrations of indium ions, gallium ions and zinc ions are all controlled between 0.05 and 0.5 mol / L.

5. The method for preparing highly dispersed nano-indium gallium zinc oxide powder according to claim 4, characterized in that: The method for preparing the reactant mixed solution comprises: Mix metal indium particles, gallium particles and zinc particles, put them into a polytetrafluoroethylene beaker, and place it on a magnetic stirrer; the heating temperature of the magnetic stirrer is set to 20-30°C, and the speed is set to 300-500rpm / min; Adding an appropriate amount of nitric acid to dissolve the indium particles, gallium particles and zinc particles to obtain a uniform mixed solution of indium nitrate, gallium nitrate and zinc nitrate; wherein the mass volume concentration of the nitric acid is 50-65%; The uniformly mixed solution was transferred to a volumetric flask through filter paper and fixed to volume to obtain a reactant mixed solution with a set concentration.

6. The method for preparing highly dispersed nano-indium gallium zinc oxide powder according to claim 1, characterized in that: In step S5, the temperature for aging the mixed solution of the reactants is 20 to 40° C., and the aging time is controlled at 24 to 48 hours.

7. The method for preparing highly dispersed nano-indium gallium zinc oxide powder according to claim 1, characterized in that: In step S6, the temperature for drying the white precipitate is 60-90° C., and the drying time is controlled at 24-36 hours.

8. The method for preparing highly dispersed nano-indium gallium zinc oxide powder according to claim 1, characterized in that: In step S7, the temperature of the precursor powder calcination treatment is 800-1200°C, the heating rate is set to 3°C / min, and the holding time is 2-8h; the cooling rate is set to 3°C / min, and cooled to 20-30°C.

9. The method for preparing highly dispersed nano-indium gallium zinc oxide powder according to claim 1, characterized in that: Step S5 also includes washing the obtained white precipitate, which specifically includes: The white precipitate was placed in a centrifuge and washed by centrifugation multiple times with pure water and anhydrous ethanol. The speed of the centrifuge was 4000-5500 rpm / min.

10. The method for preparing highly dispersed nano-indium gallium zinc oxide powder according to claim 1, characterized in that: In step S7, the precursor powder is ground before calcination, and the ground precursor powder is sieved with a 200-mesh sieve.

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