Efficient sintering method of ITO target material powder

Abstract

The invention relates to the technical field of target materials, and provides a high-efficiency sintering method of ITO target material powder, which comprises the following steps: weighing indium oxide and tin oxide powder with the purity of more than or equal to 99.99%, then firstly adding pure water and a dispersing agent to grind tin oxide for 90 + / -5 minutes, then grinding indium oxide with pure water and the dispersing agent for 120 + / -5 minutes, and finally grinding the indium oxide with pure water and the dispersing agent for 90 + / -5 minutes to obtain the high-efficiency sintering method of the ITO target material powder. The whole grinding time is 210 + / -10 min, the time is shortened, the production cost is reduced, the ground slurry is subjected to high-temperature spray granulation and twice forming, a densified plane target blank can be obtained, the densification can reach 65% or above, finally sintering is conducted, and the high-density target material with uniform crystal grains and high strength is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of target materials, and particularly relates to an efficient sintering method for ITO target material powder. Background Art

[0002] ITO (Indium Tin Oxide) refers to a compound target composed of three elements: indium, tin, and oxygen. Due to its excellent electrical conductivity, transparency, and stability, it is widely used in the optoelectronic fields such as manufacturing flat panel displays, solar panels, and various optical glasses. Among them, ITO target forms a transparent conductive electrode through sputtering coating. With the rise of various mobile devices such as smart phones and tablets, as well as emerging fields such as smart home and AI artificial intelligence, the demand for ITO target is increasing rapidly.

[0003] Currently, there are mainly two types of ITO powder sand mills: vertical and horizontal. Among them, the vertical sand mill has the characteristics of high efficiency and stability. Most traditional vertical sand mills adopt a double-tank grinding method, and the grinding time is relatively long, usually 5 hours or more. Such a long time cannot meet the production requirements. There is a need for a tank circulation grinding process to shorten the grinding time while ensuring the performance of the target material. Therefore, it is very important to solve this problem. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to propose an efficient sintering method for ITO target material powder to solve the problems in the background art.

[0005] Based on the above purpose, the present invention provides an efficient sintering method for ITO target material powder, including the following steps:

[0006] Step 1, raw material selection: Select indium oxide and tin oxide with a raw material powder purity ≥ 99.99%.

[0007] Step 2, powder weighing: Weigh tin oxide and indium oxide separately.

[0008] Step 3, tin oxide grinding: Add pure water into the grinding tank of the vertical sand mill. The added amount of pure water is 1 - 1.2 times the total weight of tin oxide. Start stirring, with a stirring speed of 50 - 150 revolutions / min. Then add a dispersant. Finally, add the tin oxide weighed in Step 2 into the grinding tank. After stirring for 10 minutes, start grinding. The grinding speed is 1500 - 1600 revolutions / min. Stop grinding after 90 ± 5 minutes of grinding, and the particle size D50 of the tin oxide slurry obtained is 0.35 - 0.4 um.

[0009] Step 4, Mixing and Grinding of Indium Oxide: Continue to add pure water into the grinding tank. The added amount of pure water is the same as the total weight of tin oxide and indium oxide. Then add a dispersant, and stir at a speed of 100 - 300 revolutions per minute. Add the weighed indium oxide powder from Step 2 into the grinding tank. After stirring for 10 minutes, start grinding at a rotational speed of 1500 - 1600 revolutions per minute. Stop grinding after 120 ± 5 minutes of grinding to obtain a final slurry with a particle size D50 of 0.3 - 0.35 μm.

[0010] Step 5, Spray Granulation: Pass the slurry obtained in Step 4 through a high-temperature spray granulator for powder granulation to obtain spherical powder meeting the standards.

[0011] Step 6, Molding: For the first molding, add the qualified powder into a planar molding die, and start pressing the target using a ten-thousand-ton hydraulic press to obtain a regular and dense target embryo. For the second molding, wrap the qualified target embryo and place it in a cold isostatic press for pressing to obtain a densified planar target embryo.

[0012] Step 7, Sintering: Place the target embryo after cold isostatic pressing into an atmospheric furnace for sintering to obtain a high-density target material with uniform crystal grains.

[0013] Preferably, the specific surface area of the indium oxide selected in Step 1 is 11.5 ± 1 m 2 / g, and the specific surface area of the tin oxide is 10 - 12 m 2 / g.

[0014] Preferably, the weight ratio of indium oxide to tin oxide in Step 2 = 90:10.

[0015] Preferably, the added amount of the dispersant in Step 4 is 0.3% - 0.5% of the total weight of tin oxide and indium oxide.

[0016] Preferably, the inlet air temperature of the high-temperature spray granulator in Step 5 is 187 ± 5 °C, the outlet air temperature is 105 ± 5 °C, and the rotational speed of the atomizer is 8500 revolutions per minute.

[0017] Preferably, the pressure for the first molding in Step 6 is 25 - 40 mpa, and the time is 10 - 15 min.

[0018] Preferably, the pressure for the second molding in Step 6 is 300 mpa, and the time is 1.5 - 2 h.

[0019] Preferably, the sintering temperature in Step 7 is 1500 - 1600 °C, the time is 15 - 25 h, the heating rate is 0.05 - 1.5 °C / min, and oxygen is introduced during the sintering process.

[0020] Advantages of the present invention: By weighing indium oxide and tin oxide powders with a purity of ≥99.99%, first pure water and a dispersant are added to grind tin oxide for 90 ± 5 minutes, and then pure water and a dispersant are used to grind indium oxide for 120 ± 5 minutes. The total grinding time is 210 ± 10 minutes, which shortens the time and reduces production costs. The ground slurry is subjected to high-temperature spray granulation and then formed twice to obtain a densified planar target blank with a densification rate of over 65%. Finally, sintering is carried out to obtain a high-density target material with uniform grains and high strength. Specific embodiments

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments.

[0022] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second", and similar terms used in the present invention do not indicate any order, quantity, or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this term cover the elements or objects listed after this term and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0023] This embodiment provides an efficient sintering method for ITO target powder, including the following steps:

[0024] S1, Raw material selection: Select indium oxide and tin oxide with a raw material powder purity of ≥99.99%. The specific surface area of indium oxide is between 11 m 2 / g, and the specific surface area of tin oxide is 11 m 2 / g;

[0025] S2, Powder weighing: Weigh indium oxide and tin oxide separately. The weight ratio of indium oxide to tin oxide = 90:10;

[0026] S3, Tin Oxide Grinding: Add pure water into the grinding tank of the vertical sand mill. The amount of pure water added is 1 - 1.2 times the total weight of tin oxide. Start stirring with a stirring speed of 150 revolutions per minute. Then add a dispersant. Finally, add the weighed tin oxide from Step 2 into the grinding tank. After stirring for 10 minutes, start grinding at a grinding speed of 1550 revolutions per minute. Stop grinding after 90 minutes of grinding to obtain tin oxide slurry with a particle size D50 of 0.35 μm.

[0027] S4, Indium Oxide Mixing and Grinding: Continue to add pure water into the grinding tank. The amount of pure water added is the same as the total weight of tin oxide and indium oxide. Then add a dispersant. The amount of dispersant added is 0.4% of the total weight of tin oxide and indium oxide. Stir at a speed of 200 revolutions per minute. Add the weighed indium oxide powder from Step 2 into the grinding tank. After stirring for 10 minutes, start grinding at a grinding speed of 1600 revolutions per minute. Stop grinding after 120 minutes of grinding to obtain the final slurry with a particle size D50 of 0.3 μm.

[0028] S5, Spray Granulation: Pass the slurry obtained in Step 4 through a high-temperature spray granulator for powder granulation. The inlet air temperature of the high-temperature spray granulator is 187°C, the outlet air temperature is 105°C, and the atomizer speed is 8500 revolutions per minute to obtain spherical powder that meets the standards.

[0029] S6, Primary Forming: Add the qualified powder into a flat forming mold, and start pressing the target with a ten-thousand-ton hydraulic press at a pressure of 40 mpa for 15 minutes to obtain a regular and dense target embryo.

[0030] S7, Secondary Forming: Wrap the qualified target embryo and place it in a cold isostatic press for pressing at a pressure of 300 mpa for 2 hours to obtain a densified flat target embryo.

[0031] S8, Sintering: Place the target embryo after cold isostatic pressing into an atmospheric furnace for sintering at a sintering temperature of 1600°C for 25 hours with a heating rate of 1.5°C per minute. Oxygen is introduced during the sintering process to obtain a high-density target material with uniform crystal grains.

[0032] To verify the superiority of the grinding time in this implementation, 36 groups of experiments were conducted with different grinding times for each group. The results are as follows in the table:

[0033]

[0034] This example is the 15th experimental group, and the density of the target material is 7.1388 g / cm 3, the density of the test group with a shorter grinding time is higher, and the density of the test group with a longer grinding time is comparable. Therefore, this embodiment is more excellent, the time is shortened, the production cost is reduced, the ground slurry is spray granulated at high temperature, and then formed twice to obtain a densified planar target blank with a densification rate of over 65%. Finally, sintering is carried out to obtain a high-density target material with uniform grains and high strength.

[0035] Those of ordinary skill in the art should understand that any discussion of the above embodiments is exemplary only and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above. For the sake of brevity, they are not provided in detail. Any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An efficient sintering method for ITO target powder, characterized in that, It includes the following steps: Step 1, raw material selection: Select indium oxide and tin oxide with the purity of raw material powder ≥99.99%. Step 2, powder weighing: Weigh indium oxide and tin oxide separately. Step 3, tin oxide grinding: Add pure water into the grinding tank of the vertical sand mill. The added amount of pure water is 1 - 1.2 times the total weight of tin oxide. Start stirring with a stirring speed of 50 - 150 revolutions per minute. Then add a dispersant. Finally, add the tin oxide weighed in Step 2 into the grinding tank. After stirring for 10 minutes, start grinding with a grinding speed of 1500 - 1600 revolutions per minute. Stop grinding after 90 ± 5 minutes of grinding to obtain tin oxide slurry with a particle size D50 of 0.35 - 0.4 μm. Step 4, indium oxide mixed grinding: Continue to add pure water into the grinding tank. The added amount of pure water is the same as the total weight of tin oxide and indium oxide. Then add a dispersant with a stirring speed of 100 - 300 revolutions per minute. Add the indium oxide powder weighed in Step 2 into the grinding tank. After stirring for 10 minutes, start grinding with a grinding speed of 1500 - 1600 revolutions per minute. Stop grinding after 120 ± 5 minutes of grinding to obtain the final slurry with a particle size D50 of 0.3 - 0.35 μm. Step 5, spray granulation: Pass the slurry obtained in Step 4 through a high-temperature spray granulator for powder granulation to obtain spherical powder meeting the standards. Step 6, forming: First forming, add the qualified powder into a flat forming mold, and start pressing the target with a ten-thousand-ton hydraulic press to obtain a regular and dense target blank. Second forming, wrap the qualified target blank and place it in a cold isostatic press for pressing to obtain a densified flat target blank. Step 7, sintering: Put the target blank after cold isostatic pressing into an atmospheric furnace for sintering to obtain a high-density target material with uniform grains.

2. The high-efficiency sintering method of an ITO target powder according to claim 1, wherein, The specific surface area of indium oxide selected in the first step is 11.5±1 m 2 / g, and the specific surface area of tin oxide is 10-12 m 2 / g.

3. The high-efficiency sintering method of an ITO target powder according to claim 1, characterized in that, In Step 2, the weight ratio of indium oxide to tin oxide = 90:

10.

4. The high-efficiency sintering method of an ITO target powder according to claim 1, characterized in that, In Step 4, the added amount of the dispersant is 0.3% - 0.5% of the total weight of tin oxide and indium oxide.

5. The high-efficiency sintering method of an ITO target powder according to claim 1, characterized in that In Step 5, the inlet air temperature of the high-temperature spray granulator is 187 ± 5°C, the outlet air temperature is 105 ± 5°C, and the atomizer speed is 8500 revolutions per minute.

6. The high-efficiency sintering method for an ITO target powder according to claim 1, characterized in that, In Step 6, the pressure for the first forming is 25 - 40 mpa and the time is 10 - 15 minutes.

7. The high-efficiency sintering method of an ITO target powder according to claim 1, characterized in that In Step 6, the pressure for the second forming is 300 mpa and the time is 1.5 - 2 hours.

8. The high-efficiency sintering method for an ITO target powder according to claim 1, wherein, In Step 7, the sintering temperature is 1500 - 1600°C, the time is 15 - 25 hours, the heating rate is 0.05 - 1.5°C / min, and oxygen is introduced during the sintering process.

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