Method for preparing TZO powder by adopting plasma spheroidizing process

Abstract

The invention relates to the field of magnetron sputtering coating target material powder processing, and particularly discloses a method for preparing TZO powder through a plasma spheroidizing process. The method for preparing the TZO powder through the plasma spheroidizing process comprises the following steps that S1, zinc oxide powder and tin oxide powder are mixed and subjected to ball milling, and pretreated zinc-tin oxide mixed powder is prepared; s2, the prepared pretreated zinc tin oxide mixed powder is subjected to alkali washing, water washing and drying, and zinc tin oxide mixed powder is prepared; s3, the prepared zinc tin oxide mixed powder is subjected to plasma spheroidizing treatment under the condition that the temperature ranges from 2000 DEG C to 2300 DEG C, cooling is conducted, and TZO powder is prepared; according to the preparation technology, through the preparation technology that ball milling and alkali washing are matched with plasma spheroidizing, the prepared TZO powder has the good sphericity degree and uniformity, and the good flatness and compactness are achieved when the TZO powder is applied to the zinc tin oxide target material.

Description

Technical Field

[0001] The present application relates to the field of magnetron sputtering coating target powder processing, and more specifically, it relates to a method for preparing TZO powder by using a plasma spheroidization process. Background Art

[0002] Magnetron sputtering coating is an advanced physical vapor deposition (PVD) technology. Its core is to use the sputtering effect to transfer the target powder to the surface of the substrate to form a thin film. Magnetron coating has a wide range of applications. In the electronics field, magnetron coating can be used to prepare semiconductor devices, magnetic materials and optoelectronic devices. In the optical field, it can be used to produce transparent conductive films, reflective films, filters, etc. In the medical field, magnetron coating can be used to produce medical devices and biosensors. In the automotive field, it can be used to improve the appearance and wear resistance of the automotive surface. In addition, magnetron coating can also play an important role in solar cells, battery energy storage systems and other fields.

[0003] The commonly used targets for magnetron sputtering coating are metal targets, alloy targets, and ceramic compound targets. Among them, zinc tin oxide (TZO) target is a commonly used alloy target, mainly composed of zinc oxide (ZnO) and tin oxide (SnO2). Zinc tin oxide target has high transmittance, low resistivity, good mechanical properties and stability, and can be widely used in solar cells, flat panel displays, touch screens, LEDs and other fields.

[0004] The raw material of zinc tin oxide target is generally TZO powder. Common TZO powder is generally prepared by a spray drying process. The sphericity and uniformity of the prepared TZO powder are low, which reduces the application performance in zinc tin oxide target. Summary of the invention

[0005] In order to solve the problem that the sphericity and uniformity of TZO powder prepared by conventional preparation processes are low, thereby reducing the application performance in zinc tin oxide targets, the present application provides a method for preparing TZO powder using a plasma spheroidization process.

[0006] The present application provides a method for preparing TZO powder by plasma spheroidization process, which adopts the following technical scheme: A method for preparing TZO powder by plasma spheroidization process comprises the following steps: S1, zinc oxide powder and tin oxide powder are mixed and ball-milled to obtain pretreated zinc oxide tin mixed powder; S2, alkali washing the obtained pretreated zinc oxide tin mixed powder, washing with water and drying to obtain zinc oxide tin mixed powder; S3. Plasma spheroidizing the obtained zinc oxide-tin mixed powder at a temperature of 2000-2300° C., cooling the mixture to obtain TZO powder.

[0007] By adopting the above technical scheme, the zinc oxide powder and the tin oxide powder are first mixed and ball-milled. During the ball-milling process, the zinc oxide powder and the tin oxide powder are evenly mixed and crushed and refined, thereby improving the mixing uniformity of the zinc oxide powder and the tin oxide powder, increasing the specific surface area of ​​the zinc oxide powder and the tin oxide powder, and crushing the impurities in the zinc oxide powder and the tin oxide powder; and then through alkali washing treatment, not only the impurity components in the pre-treated zinc oxide tin powder can be removed, but also a uniform microscopic corrosion surface can be formed on the surface of the pre-treated zinc oxide tin mixed powder, thereby improving the pre-treated zinc oxide tin mixed powder in the subsequent plasma spheroidization. The surface heating uniformity in the process is improved, thereby improving the uniformity and stability of the plasma spheroidization treatment; finally, plasma spheroidization treatment is carried out, so that the surface or the whole of the zinc oxide tin mixed powder is heated and melted under optimal temperature conditions and shrinks into a sphere with a smooth surface and uniform shape. The optimal heating temperature can make the surface or the whole of the zinc oxide powder and the tin oxide powder melt evenly, and there will be no problems of slow melting rate or excessive melting, thereby improving the processing efficiency. After cooling and solidification, TZO powder with good sphericity and uniformity is obtained, which has good flatness and density when used in zinc oxide tin target materials.

[0008] Preferably, the weight ratio of the zinc oxide powder to the tin oxide powder is (2:3)-(3:2).

[0009] By adopting the above technical solution, the dosage of zinc oxide powder and tin oxide powder is optimized, and the application performance of the prepared TZO powder in magnetron sputtering coating can be improved.

[0010] Preferably, the particle size of the zinc oxide powder is 10-200 μm, and the particle size of the tin oxide powder is 10-200 μm.

[0011] By adopting the above technical scheme, the process for preparing TZO powder of the present application can be applied to the processing of zinc oxide powder and tin oxide powder with a particle size in the range of 10-200 μm, has high processing efficiency, can process zinc oxide powder and tin oxide powder with large differences in particle size, and will not reduce the sphericity and uniformity of the prepared TZO powder.

[0012] Preferably, the specific steps of plasma spheroidization in the S3 step are as follows: controlling the vacuum degree of the plasma spheroidization equipment to 5×10-3-5×10-2Pa, the working current of the plasma equipment to 2500-3000A, the working voltage to 60V-80V, using hydrogen as a carrier gas to send the zinc oxide tin mixed powder into the plasma spheroidization equipment for plasma spheroidization, and then falling into the cooling chamber under the working atmosphere for cooling to obtain spheroidized TZO powder.

[0013] By adopting the above technical scheme, hydrogen is used as a carrier gas to transport the zinc oxide tin mixed powder into the plasma spheroidization equipment. Under the working atmosphere of argon or helium, the optimal plasma spheroidization parameters are controlled to make the zinc oxide tin mixed powder melt and spheroidize. The optimal vacuum degree can make the zinc oxide tin mixed powder with smaller particle size contact and fuse with each other, and make the zinc oxide tin moderate powder surface with larger particle size melt evenly, which can better optimize the particle size of the obtained TZO powder. If the vacuum degree is large or small, the sphericity and uniformity of the obtained TZO powder are both low. The optimal working current and working voltage of the plasma equipment can make the zinc oxide tin mixed powder stably undergo plasma spheroidization treatment. Therefore, by controlling the specific parameters of the plasma spheroidization equipment, such as the vacuum degree, the working current and working voltage of the plasma equipment, the spheroidization degree and uniformity of the obtained TZO powder can be further improved, so that the TZO powder has excellent physical properties and application performance.

[0014] Preferably, the feeding amount of the zinc oxide tin mixed powder is 180-200 g / min, the flow rate of hydrogen is 500-520 L / h, the working atmosphere of plasma spheroidization is argon or helium, and the flow rate of helium or argon is 3200-3400 L / h.

[0015] By adopting the above technical scheme, the feeding amount of zinc oxide tin mixed powder is controlled within the range of 180-200g / min, and the hydrogen flow rate is 500-520L / h, so that the zinc oxide tin powder can be evenly dispersed and enter the plasma equipment; argon or helium is selected as the working atmosphere, and its flow rate is 3200-3400L / h, which can ensure that the powder is evenly heated during the plasma spheroidization process, promote the formation of spherical TZO powder, and improve the sphericity and particle size uniformity of the TZO powder.

[0016] Preferably, the ball milling speed in step S1 is 600-1000 r / min, and the ball milling time is 2-4 h.

[0017] By adopting the above technical solution, the rotation speed and time parameters in the ball milling process are optimized, so that the zinc oxide powder and the tin oxide powder can be mixed more evenly during the ball milling process, thereby improving the uniformity and sphericity of the pretreated zinc oxide and tin mixed powder.

[0018] Preferably, in step S2, an alkali cleaning agent is used for alkali cleaning, and the alkali cleaning agent is prepared from the following raw materials in weight percentage: Alkaline hydroxide 8-15% Homogenizer 4-6% Wetting agent 3-5% Surfactant 0.5-1.5% Water balance; The homogenizer is composed of 3-glycidyloxypropylmethyldiethoxysilane, organosilicon quaternary ammonium salt and polyacrylamide in a weight ratio of 1:(3-4):(1-2).

[0019] By adopting the above technical scheme, the alkaline hydroxide in the alkali cleaning agent can effectively remove impurities in the zinc oxide tin mixed powder, and micro-corrode the surface of the zinc oxide tin mixed powder, thereby improving the purity and surface uniformity of the powder; 3-glycidyloxypropylmethyldiethoxysilane can increase the dispersion distance of the zinc oxide tin powder in the alkali cleaning agent, and under the joint action of the organosilicon quaternary ammonium salt and polyacrylamide, the alkali cleaning agent can be uniformly penetrated and dispersed and adhered to the surface of the zinc oxide tin mixed powder. The homogenizer composed of the above-mentioned can improve the dispersion uniformity of the alkali cleaning agent in the zinc oxide tin mixed powder, and be uniformly and stably adsorbed on the surface of the zinc oxide tin mixed powder, thereby improving the corrosion uniformity of the zinc oxide tin powder; the wetting agent can produce a good synergistic effect with the homogenizer, improve the wetting and penetration performance of the alkali cleaning agent, further improve the corrosion uniformity and treatment efficiency of the alkali cleaning agent on the zinc oxide tin powder, and thereby improve the sphericity and uniformity of the spheroidized TZO powder.

[0020] Preferably, the wetting agent consists of polyvinyl pyrrolidone and acetylene glycol surfactant in a weight ratio of (1-3):1.

[0021] By adopting the above technical solution and using polyvinyl pyrrolidone and acetylene glycol surfactants in an optimal dosage ratio as wetting agents, the penetration uniformity of the zinc oxide tin mixed powder can be effectively improved, thereby improving the sphericity and uniformity of the final TZO powder.

[0022] Preferably, the alkaline hydroxide is potassium hydroxide and / or sodium hydroxide, and the surfactant is at least one of a sulfonate surfactant, a carboxylate surfactant and a fatty alcohol polyoxyethylene ether surfactant.

[0023] By adopting the above technical scheme, the above hydroxide can provide better alkaline conditions for the alkaline cleaning agent, and the above surfactant can preferably further reduce the surface energy of the zinc oxide tin mixed powder, thereby improving the alkaline cleaning effect, effectively removing impurities in the zinc oxide tin mixed powder and homogenizing the zinc oxide tin mixed powder, thereby improving the purity and quality of the TZO powder.

[0024] Preferably, the alkali washing temperature is 45-65°C and the time is 20-40 minutes. By adopting the above technical solution, the optimal alkali washing conditions can make the alkali washing agent evenly dispersed in the pretreated zinc oxide tin mixed powder, effectively remove impurities in the pretreated zinc oxide tin mixed powder, and further improve the purity and uniformity of the powder.

[0025] In summary, this application has the following beneficial effects: 1. The method of preparing TZO powder by plasma spheroidization process in the present application, through the preparation process of ball milling and alkali washing combined with plasma spheroidization, the prepared TZO powder has good sphericity and uniformity, and has good flatness and density when applied to zinc oxide tin target.

[0026] 2. By optimizing the plasma spheroidization parameters, the plasma spheroidization temperature is controlled to be 2000-2300℃ and the vacuum degree is 5×10 -3 -5×10 -2 Pa, the working current of the plasma equipment is 2500-3000A, the working voltage is 60V-80V, the feeding amount of zinc oxide tin mixed powder is 180-200g / min, hydrogen is used as the carrier gas, the flow rate of hydrogen is 500-520L / h, the working atmosphere of plasma spheroidization is argon or helium, and the flow rate of helium or argon is 3200-3400L / h, which can make the zinc oxide tin mixed powder with smaller particle size contact and fuse with each other, and make the zinc oxide tin with larger particle size moderate powder surface melt uniformly, which can better optimize the particle size of the obtained TZO powder, ensure that the powder is evenly heated during the plasma spheroidization process, and improve the sphericity and particle size uniformity of the TZO powder.

[0027] 3. Use an alkaline cleaning agent made of alkaline hydroxide, a homogenizer, a wetting agent, a surfactant and water. The homogenizer is composed of 3-glycidyloxypropylmethyldiethoxysilane, silicone quaternary ammonium salt and polyacrylamide. The wetting agent is composed of polyvinylpyrrolidone and acetylene glycol surfactant. The alkaline cleaning agent is dispersed uniformly in the zinc oxide tin mixed powder and is evenly and stably adsorbed on the surface of the zinc oxide tin mixed powder, thereby improving the corrosion uniformity of the zinc oxide tin powder, further improving the corrosion uniformity and treatment efficiency of the alkaline cleaning agent on the zinc oxide tin powder, and thereby improving the sphericity and uniformity of the spheroidized TZO powder. DETAILED DESCRIPTION

[0028] The present application is further described in detail below with reference to the embodiments.

[0029] Preparation example of alkaline cleaning agent Preparation Example 1 Preparation Example 1 discloses an alkaline cleaning agent, which is prepared by the following steps: 0.8 kg of sodium hydroxide as an alkaline hydroxide and 0.6 kg of a homogenizer (composed of polyacrylamide and vinyltrimethoxysilane in a weight ratio of 1:3) were added to 8.05 kg of water, and after stirring to dissolve, 0.4 kg of polyvinylpyrrolidone as a wetting agent and 0.15 kg of sodium dodecylbenzene sulfonate as a surfactant were added, and stirred evenly to prepare an alkaline cleaning agent; Polyacrylamide: molecular weight 8-12 million; polyvinylpyrrolidone: PVP K30, content 99%.

[0030] Preparation Example 2-3 The difference between Preparation Example 2-3 and Preparation Example 1 is that the amount of raw materials used and the preparation conditions are different, see Table 1 below for details.

[0031] Table 1 Raw material dosage and preparation conditions of Preparation Examples 1-3 Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that the homogenizer is different. The homogenizer consists of 3-glycidyloxypropylmethyldiethoxysilane, organosilicon quaternary ammonium salt and polyacrylamide. The amount of 3-glycidyloxypropylmethyldiethoxysilane is 0.1kg, the amount of organosilicon quaternary ammonium salt is 0.4kg, the amount of polyacrylamide is 0.1kg, the organosilicon quaternary ammonium salt is octadecyldimethyltrimethylsilylpropylammonium chloride, and the content is 60%. The others are the same as Preparation Example 1.

[0032] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 1 is that the homogenizer consists of 3-glycidyloxypropylmethyldiethoxysilane, silicone quaternary ammonium salt and polyacrylamide, the amount of 3-glycidyloxypropylmethyldiethoxysilane is 0.1kg, the amount of silicone quaternary ammonium salt is 0.3kg, the amount of polyacrylamide is 0.2kg, and the others are the same as Preparation Example 1.

[0033] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 1 is that the homogenizer consists of vinyltrimethoxysilane, hydroxyethyl cellulose and polyethylene glycol 800, the amount of vinyltrimethoxysilane is 0.1 kg, the amount of hydroxyethyl cellulose is 0.2 kg, the amount of polyethylene glycol 800 is 0.3 kg, and the rest is the same as Preparation Example 1.

[0034] Preparation Example 7 The difference between Preparation Example 7 and Preparation Example 5 is that the wetting agent is different. The wetting agent in Preparation Example 7 consists of polyvinyl pyrrolidone and acetylene glycol surfactant. The amount of polyvinyl pyrrolidone is 0.3 kg, the amount of acetylene glycol surfactant is 0.1 kg, and the acetylene glycol surfactant is Evonik SURFYNOL 104E. The rest is the same as Preparation Example 5.

[0035] Preparation Example 8 The difference between Preparation Example 8 and Preparation Example 5 is that the wetting agent consists of polyvinyl pyrrolidone and acetylene glycol surfactant, the amount of polyvinyl pyrrolidone used is 0.2 kg, the amount of acetylene glycol surfactant used is 0.2 kg, the acetylene glycol surfactant is Evonik SURFYNOL 104E, and the rest is the same as Preparation Example 5. Example

[0036] Example 1 Example 1 discloses a method for preparing TZO powder using a plasma spheroidization process, comprising the following steps: S1. Mix 6 kg of zinc oxide powder and 4 kg of tin oxide powder, and use a ball mill to perform ball milling, using stainless steel balls as abrasives and water as a ball milling medium, and control the ball milling speed to be 600 r / min for 4 hours to obtain a pretreated zinc oxide tin mixed powder; wherein the zinc oxide powder has a particle size of 10-200 μm and a purity of 99.99%, and the tin oxide powder has a particle size of 10-200 μm and a purity of 99.99%; S2, using the alkaline cleaning agent prepared in Preparation Example 1 to perform alkaline washing on the obtained pretreated zinc oxide tin mixed powder, controlling the temperature of the alkaline washing to be 65° C. and the time to be 20 min, filtering after the alkaline washing, and washing with water for 2-3 times, filtering, and drying to obtain a zinc oxide tin mixed powder; S3, use plasma spheroidization equipment, control the vacuum degree of plasma spheroidization equipment to 5×10 -3 Pa, the working current of the plasma equipment is 2500A, the working voltage is 60VV, hydrogen is used as the carrier gas, the flow rate of hydrogen is 500L / h, the zinc oxide tin mixed powder is fed into the plasma spheroidization equipment at a feeding amount of 180g / min for plasma spheroidization, the temperature in the working chamber of the plasma spheroidization is 2000℃, the working atmosphere of the plasma spheroidization is argon or helium, the flow rate of helium or argon is 3400L / h, and then it falls into the cooling chamber under the working atmosphere for cooling to obtain spheroidized TZO powder.

[0037] Example 2-3 The difference between Example 2-3 and Example 1 is that the preparation process parameters are different, see Table 2 below for details.

[0038] Table 2 Preparation process parameters of Examples 1-3 Embodiment 4-8 The difference between Examples 4-8 and Example 1 is that the sources of the alkaline cleaning agent are different, see Table 3 below for details.

[0039] Table 3 Sources of the alkaline detergents of Examples 4-8 Example Sources of alkaline cleaning agents Example 4 Preparation Example 4 Example 5 Preparation Example 5 Example 6 Preparation Example 6 Example 7 Preparation Example 7 Example 8 Preparation Example 8 Example 9 The difference between Example 9 and Example 1 is that the feeding amount of the zinc oxide tin mixed powder is 220 g / min, and the other parts are the same as Example 1.

[0040] Example 10 The difference between Example 10 and Example 1 is that the carrier gas flow rate of plasma spheroidization is 450 g / min, and the rest is the same as Example 1.

[0041] Embodiment 11 The difference between Example 11 and Example 1 is that the flow rate of the working atmosphere for plasma spheroidization is 4000 L / h, and the rest is the same as Example 1.

[0042] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the temperature of plasma spheroidization is 2500° C., and the other conditions are the same as those of Example 1.

[0043] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that step S2 is not performed, and the pretreated zinc tin oxide powder obtained in step S1 is directly subjected to plasma spheroidization treatment, and the rest is the same as Example 1.

[0044] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the ball milling treatment in step S1 is not performed, and 6.5 kg of zinc oxide powder and 3.5 kg of tin oxide powder are mixed and then directly subjected to alkali washing treatment, and then plasma spheroidization treatment is performed. The rest is the same as Example 1.

[0045] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that after 6.5 kg of zinc oxide powder and 3.5 kg of tin oxide powder are mixed, alkali washing is first performed, then ball milling is performed, and then plasma spheroidization is performed. The specific parameters are the same as those in Example 1.

[0046] Performance testing The following is a performance test of the TZO powders obtained in Examples 1-11 and Comparative Examples 1-4: 1. Sphericity detection Weigh 2 g of TZO powder, spread the TZO powder on the detection platform, use a scanning electron microscope connected to IPP software (Image-ProPlus) to scan the TZO powder, and detect and calculate the sphericity (unit: %) of the TZO powder in the SEM image scanned by the scanning electron microscope. Sphericity = number of spherical TZO powders / total number of TZO powders * 100%. Test and record the test results; 2. Particle size uniformity detection: Use Malvern laser particle size analyzer to detect the particle size distribution ratio (unit: %) of TZO powder, test and record the test results; The following are the performance test data of TZO powders prepared in Examples 1-11 and Comparative Examples 1-4, see Table 4 and Table 5 below for details.

[0047] Table 4 Sphericity test data of TZO powders of Examples 1-11 and Comparative Examples 1-4 Table 5 Particle size distribution data of TZO powder of Examples 1-11 and Comparative Examples 1-4 Combining Examples 1-3 and Examples 4-8 and Tables 4-5, it can be concluded that the TZO powder is treated with an alkaline detergent prepared by compounding a homogenizer and a wetting agent in an optimal dosage ratio of the present application. The sphericity of the obtained TZO powder is better and the particle size distribution width is narrower, indicating that the particle size uniformity is better. Compared with Example 5, the sphericity and particle size distribution width of Examples 7-8 are narrower, and compared with Example 1, the sphericity of Examples 4-5 is increased by 2%, and the particle size distribution width is significantly narrowed.

[0048] Combining Example 1 and Examples 9-11, Comparative Example 1 and Tables 4-5, it can be seen that optimizing the process parameters of the plasma spheroidization of the present application can significantly improve the sphericity and particle size uniformity of the obtained TZO powder; in Example 9, the feed amount of the powder is increased, the sphericity of the obtained TZO powder is reduced, and the particle size distribution width is widened, which may be due to the excessive feed amount, resulting in uneven surface or overall melting; in Example 10, the carrier gas flow rate is reduced, the sphericity of the obtained TZO powder is reduced, and the particle size distribution width is widened, which may be due to the change of the carrier gas flow rate. The amount reduces the stability of powder feeding; in Example 11, the flow rate of the working atmosphere is increased, the sphericity of the obtained TZO powder is reduced, and the width of the particle size distribution is widened, which may be because the working atmosphere with a larger flow rate reduces the spheroidization stability of the TZO powder; in Comparative Example 1, the temperature of plasma spheroidization is increased, the sphericity of the obtained TZO powder is reduced, the width of the particle size distribution is widened, and the number of large-particle-size TZO powders increases, which may be because the higher melting temperature causes the small-particle powder to be excessively melted and combined, thereby making the finished particle size of the TZO powder larger and the distribution wider.

[0049] From Example 1 and Comparative Examples 2-4 and Tables 4-5, it can be seen that the sphericity and particle size distribution of the TZO powder obtained by the process of first ball milling, then alkaline washing, and then plasma spheroidization of the present application are relatively uniform. In Comparative Example 3, no ball milling was performed, and the overall sphericity of the TZO powder obtained was reduced, the particle size distribution width became wider, and the overall particle size was larger.

[0050] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing TZO powder using a plasma spheroidization process, characterized in that: The following steps are involved: S1, zinc oxide powder and tin oxide powder are mixed and ball-milled to obtain pretreated zinc oxide tin mixed powder; S2, alkali washing the obtained pretreated zinc oxide tin mixed powder, washing with water and drying to obtain zinc oxide tin mixed powder; S3. Plasma spheroidizing the obtained zinc oxide-tin mixed powder at a temperature of 2000-2300° C., cooling the mixture to obtain TZO powder.

2. The method for preparing TZO powder by plasma spheroidization process according to claim 1, characterized in that: The weight ratio of the zinc oxide powder to the tin oxide powder is (2:3)-(3:2).

3. The method for preparing TZO powder by plasma spheroidization process according to claim 1, characterized in that: The particle size of the zinc oxide powder is 10-200 μm, and the particle size of the tin oxide powder is 10-200 μm.

4. The method for preparing TZO powder by plasma spheroidization process according to claim 1, characterized in that: The specific steps of plasma spheroidization in step S3 are as follows: Control the vacuum degree of the plasma spheroidization equipment to 5×10 -3 -5×10 -2 Pa, the working current of the plasma equipment is 2500-3000A, the working voltage is 60V-80V, and the zinc oxide tin mixed powder is sent to the plasma spheroidization equipment with hydrogen as the carrier gas for plasma spheroidization, and then falls into the cooling chamber under the working atmosphere for cooling to obtain spheroidized TZO powder.

5. The method for preparing TZO powder by plasma spheroidization process according to claim 4, characterized in that: The feeding amount of the zinc oxide tin mixed powder is 180-200 g / min, the flow rate of hydrogen is 500-520 L / h, the working atmosphere of plasma spheroidization is argon or helium, and the flow rate of helium or argon is 3200-3400 L / h.

6. The method for preparing TZO powder by plasma spheroidization process according to claim 1, characterized in that: In the step S1, the rotation speed of the ball mill is 600-1000 r / min, and the ball milling time is 2-4 h.

7. The method for preparing TZO powder by plasma spheroidization process according to claim 1, characterized in that: In the step S2, an alkali cleaning agent is used for alkali cleaning, and the alkali cleaning agent is prepared from the following raw materials in percentage by weight: Alkaline hydroxide 8-15% Homogenizer 4-6% Wetting agent 3-5% Surfactant 0.5-1.5% Water balance; The leveling agent is composed of 3-glycidyloxypropylmethyldiethoxysilane, organosilicon quaternary ammonium salt and polyacrylamide in a weight ratio of 1:(3-4):(1-2).

8. The method for preparing TZO powder by plasma spheroidization process according to claim 7, characterized in that: The wetting agent is composed of polyvinyl pyrrolidone and acetylene glycol surfactant in a weight ratio of (1-3):

1.

9. The method for preparing TZO powder by plasma spheroidization process according to claim 7, characterized in that: The alkaline hydroxide is potassium hydroxide and / or sodium hydroxide, and the surfactant is at least one of a sulfonate surfactant, a carboxylate surfactant and a fatty alcohol polyoxyethylene ether surfactant.

10. The method for preparing TZO powder by plasma spheroidization process according to claim 1, characterized in that: The alkali washing is carried out at a temperature of 45-65°C and for a time of 20-40 minutes.

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