An In4Sn3O 12 Target material and method for producing the same

Abstract

The application provides an In4Sn3O 12 Target material and preparation method thereof. The target material of the application has a density of greater than or equal to 99.2%, a resistivity of less than or equal to 8*10 ‑4 Ω*cm, and high uniformity. The application also provides a preparation method of the In4Sn3O 12 Target material. The method uses indium and tin as raw materials, dissolves the raw materials by acid to obtain a mixed metal salt solution, drops the mixed metal salt solution into ammonia water to precipitate indium hydroxide and tin hydroxide, dries the indium hydroxide and tin hydroxide to obtain a mixed powder, and heats and reacts the mixed powder to obtain an In4Sn3O 12 Powder. The In4Sn3O 12 Powder is activated by an organic acid and granulated to obtain a granulated powder, the granulated powder is formed by a mold to obtain a green body, and the green body is sintered to obtain the In4Sn3O 12 Target material.

Description

Technical Field

[0001] This invention belongs to the field of low-indium target preparation technology, specifically relating to an In4Sn3O target. 12 Target materials and their preparation methods. Background Technology

[0002] Transparent conductive oxide (TCO) films are key materials in displays, heterojunction solar cells, Low-E glass, and electrochromic devices. Indium tin oxide (ITO) targets are the main raw material for the industrial preparation of TCO films. Commonly used ITO targets have an indium oxide mass fraction greater than or equal to 90% (i.e., 90 / 10 ITO targets), corresponding to an indium content of 74.4% or higher. Due to the high price and scarcity of indium, the cost of ITO targets remains high, which limits their large-scale application and promotion in photovoltaics and Low-E glass. Therefore, there is an urgent need for a low-cost target with excellent photoelectric properties.

[0003] In4Sn3O 12 With an indium content of only 45.6%, it is a low-indium material that has attracted much attention and has great potential. In related technologies, CN116496081 A discloses an In4Sn3O... 12 CN118084480A discloses a low-indium target material with an indium content of 43.5-55.7%, and an In4Sn3O target material with an indium content of 43.5-55.7%. 12 Low-indium sputtering targets with an indium content of 40.5-42% are used. These technologies have some shortcomings; specifically, the low-indium sputtering target prepared by CN116496081 A has a relative density ≥98% and a resistivity ≤5×10⁻⁶. -3 Ω·cm, but the relative density of 90 / 10ITO sputtering targets used on a large scale in industry is mostly ≥99%, and the resistivity is ≤1×10 Ω·cm. -3 Ω·cm, therefore further improvements are needed for In4Sn3O 12 The density of the target material and the reduction of resistivity are important considerations. Although the low-indium target material prepared by CN 118084480A has a density ≥99.5%, in order to remove the sintering aid antimony trioxide, the target material needs to be held at a low temperature (1280-1320℃) for 20-40 hours during sintering to prevent antimony trioxide from remaining as an impurity in the target material. This process reduces the sintering efficiency of the target material and increases the sintering cost. On the other hand, the above technologies all use indium oxide and tin oxide as raw materials, and directly synthesize In4Sn3O through a solid-state reaction. 12However, the uniformity of solid-phase synthesis is relatively poor. CN116496081A improves its uniformity by pre-sintering and secondary ball milling, but this makes the process more complicated and reduces production efficiency.

[0004] Therefore, it is necessary to develop a new In4Sn3O 12 Methods for preparing target materials. Summary of the Invention

[0005] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. To this end, the present invention provides an In4Sn3O... 12 The target material is prepared by co-precipitation first, using In4Sn3O. 12 The powder form simplifies the preparation process and improves the uniformity of indium-tin mixing. Organic acid activation of In4Sn3O is employed. 12 By lowering the sintering temperature, powder materials can ultimately achieve a density ≥99.2% and a resistivity ≤8×10⁻⁶. -4 Ω·cm, and highly uniform In4Sn3O 12 base target material.

[0006] The first aspect of the present invention provides an In4Sn3O 12 The method for preparing the target material includes the following steps:

[0007] S1: Using indium and tin as raw materials, a mixed metal salt solution is obtained by acid dissolution. The mixed metal salt solution is then added dropwise to ammonia water, causing indium hydroxide and tin hydroxide precipitates to form. After drying the indium hydroxide and tin hydroxide precipitates, a mixed powder is obtained and reacted at a higher temperature to obtain In4Sn3O. 12 Powder, containing the In4Sn3O 12 Powder granulation yields granulated powder;

[0008] S2: The granulated powder is formed by molding through a mold to obtain a raw blank;

[0009] S3: Sinter the green blank to obtain In4Sn3O 12 Target material.

[0010] This invention relates to In4Sn3O 12 One technical solution in the preparation method of the target material has at least the following beneficial effects:

[0011] This invention employs a co-precipitation method to first prepare In4Sn3O 12 The powder form simplifies the preparation process and improves the uniformity of indium-tin mixing. Organic acid activation of In4Sn3O is employed. 12 By lowering the sintering temperature, powder materials can ultimately achieve a density ≥99.2% and a resistivity ≤8×10⁻⁶. -4Ω·cm, and highly uniform In4Sn3O 12 base target material.

[0012] Although coprecipitation is a conventional powder-making process widely used in various fields, and many powders can be prepared by coprecipitation, the coprecipitation process and mechanism in this invention differ from existing coprecipitation methods due to differences in material systems. In this invention, high homogeneity can be achieved by dissolving indium and tin in acid, while simplifying the process. The challenge of this invention lies in the order of the mixed solution during coprecipitation (Kc of In(OH)3 and Sn(OH)4). sp (Different), K sp The ionic equilibrium constant of a sparingly soluble substance (precipitate), also known as the solubility product, is equal to the product of the concentrations of cations and anions. When the product exceeds K... sp When precipitation occurs, a precipitate forms. For example, in this invention, both In(OH)3 and Sn(OH)4 are sparingly soluble in water, resulting in a precipitate, and a large amount of In is present in the solution. 3+ and Sn 4+ At this time, adding an alkaline solution provides OH-. - When OH - When the concentration exceeds a certain limit, In(OH)3 and Sn(OH)4 precipitates will appear. It should be noted that, due to the K... sp There are differences; if the order of addition is reversed, towards In... 3+ and Sn 4+ Ammonia water is gradually added dropwise to the solution (to provide OH-). - At this point, because the cations are in excess, and OH... - The quantity is relatively small, therefore K sp Smaller hydroxides preferentially precipitate, leading to uneven precipitation (significant differences in chemical composition between different particles). That is, even if ammonia is gradually added dropwise to the mixed solution, uneven precipitation will still occur. Furthermore, sodium silicate is typically added as a dispersant during nanopowder preparation, but for TCO targets, silicon and sodium are highly detrimental impurities. This invention addresses this by gradually adding the mixed metal salt solution dropwise to ammonia, maintaining an excess of ammonia, and controlling the dropping rate. This ensures the uniformity of the added In. 3+ and Sn 4+ Precipitation was almost simultaneous and complete, avoiding uneven precipitation and improving the uniformity of indium-tin mixing, thus activating In4Sn3O. 12 The organic acids in the powder will volatilize during the high-temperature sintering of the target material, without introducing new impurities.

[0013] Furthermore, this invention does not have particularly high requirements for powder particle size, thereby simplifying the preparation process. Due to the low requirements for powder particle size, the synthesized In4Sn3O will be... 12 Powder can be finely ground by sand milling; it is simply a matter of refining the powder through physical methods.

[0014] In this invention, the target material matrix obtained is In4Sn3O 12 It has a hexagonal crystal form, which is a completely different system from existing technologies such as Sn-doped In2O3.

[0015] The preparation method of the present invention does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are readily available, the production cost is low, and it is easy to industrialize.

[0016] According to some embodiments of the present invention, in step S1, the mass fraction of indium in the indium and tin raw materials is 39.5% to 56.8%.

[0017] In indium and tin raw materials, the mass fraction of indium is 39.5% to 56.8%, which is considered low indium and significantly reduces costs.

[0018] According to some embodiments of the present invention, in step S1, the acid includes concentrated nitric acid or concentrated hydrochloric acid.

[0019] According to some embodiments of the present invention, the concentration of the concentrated nitric acid is 50% to 65%.

[0020] Add nitric acid solution at 1.05-1.15 times the amount required to completely generate indium nitrate and tin nitrate, ensuring that the indium and tin metals can dissolve completely. After 2-5 hours of complete dissolution, a mixed metal salt solution is obtained.

[0021] According to some embodiments of the present invention, the concentration of the concentrated hydrochloric acid is 20% to 38%.

[0022] According to some embodiments of the present invention, in step S1, the concentration of the ammonia water is 20% to 28%.

[0023] According to some embodiments of the present invention, in step S1, the concentration of the ammonia water is any value of 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, or a range of any two, such as 24% to 26%.

[0024] According to some embodiments of the present invention, the amount of ammonia water used is 1.08 to 1.20 times the amount required for all indium and tin to form metal salts.

[0025] According to some embodiments of the present invention, the amount of ammonia used is any one of 1.08, 1.12, 1.14, 1.16, 1.18, or 1.20 times the amount required for all indium and tin to form metal salts, or a range of any two, such as 1.14 to 1.18 times.

[0026] According to some embodiments of the present invention, step S1 further includes adding 0.2wt% to 0.6wt% of polyvinylpyrrolidone as an organic dispersant to ammonia water to promote the complete reaction. While forming indium hydroxide and tin hydroxide precipitates, ultrasonic dispersion is turned on. After complete precipitation, the obtained indium hydroxide and tin hydroxide precipitates are centrifuged and washed to remove acid radical ions, and then spray-dried to obtain mixed powder.

[0027] According to some embodiments of the present invention, the number of centrifugal washing cycles is 3 to 6.

[0028] According to some embodiments of the present invention, in step S1, ammonia water can be placed in a stirring tank, and an organic dispersant (0.2wt% to 0.6wt% of polyvinylpyrrolidone) can be added. Stirring is started at the same time as ultrasound. The combined effect of the three can further improve the uniformity of precipitation.

[0029] According to some embodiments of the present invention, in step S1, the heating reaction process includes: holding at 500℃~600℃ for 2h~8h, holding at 1000℃~1200℃ for 3h~8h, and holding at 1300℃~1500℃ for 1h~5h. Holding at multiple temperature ranges promotes a more thorough reaction.

[0030] According to some embodiments of the present invention, in step S1, the In4Sn3O 12 The process of powder activation and granulation via organic acid includes: activating In4Sn3O 12 After ball milling the powder in a sand mill for 6 to 10 hours, powder D is obtained. 90 For a slurry with a particle size <100 nm, the slurry is transferred to a mixer, and an organic acid is added to make the acid concentration in the slurry 0.3 mol / L to 1.2 mol / L. The mixture is stirred at a speed of 50 rpm to 120 rpm for 2 h to 8 h. Then, a binder and a plasticizer are added to the slurry and stirred. The mixture is then spray-granulated to obtain granulated powder.

[0031] According to some embodiments of the present invention, the adhesive comprises 0.5-2.0 wt% PVA.

[0032] According to some embodiments of the present invention, the plasticizer comprises 0.2-1.0 wt% PEG.

[0033] According to some embodiments of the present invention, the mixing time for adding the binder and plasticizer can be 1 hour to 3 hours.

[0034] According to some embodiments of the present invention, the organic acid includes at least one selected from oxalic acid, acetic acid, citric acid, and tartaric acid.

[0035] On the one hand, the organic weak acid reacts with the powder surface, causing certain crystal planes to be preferentially corroded and destroyed, thus damaging the crystal structure and reducing the sintering activation energy; on the other hand, the organic acid salts generated in the reaction decompose at low temperature (<900℃) to form a glassy phase. The combined effect of these two aspects reduces the sintering temperature.

[0036] According to some embodiments of the present invention, in step S2, the molding pressure of the mold is 100MPa to 180MPa, and after demolding, it is cold isostatically pressed at 150MPa to 220MPa for 20min to 60min to obtain a blank.

[0037] According to some embodiments of the present invention, in step S3, the sintering process includes: heating the green blank to 600℃ to 800℃ at a rate of 0.5 to 2℃ / min and holding it at that temperature for 2h to 6h; then heating it to 1300℃ to 1450℃ at a rate of 1 to 3℃ / min while simultaneously introducing oxygen at a rate of 5L / min to 30L / min and holding it at that temperature for 1h to 5h; after the holding period, holding it at 1150℃ to 1300℃ for 5h to 10h; and finally cooling it to room temperature at a rate of 1℃ / min to 5℃ / min.

[0038] A second aspect of the present invention provides an In4Sn3O 12 The target material is prepared by the method described in the first aspect of the present invention.

[0039] This invention relates to In4Sn3O 12 One of the technical solutions for the target material has at least the following beneficial effects:

[0040] The In4Sn3O of the present invention 12 The target material has the characteristics of high density, low resistivity and high uniformity.

[0041] According to some embodiments of the present invention, the In4Sn3O 12 The target material has a density ≥99.2% and a resistivity ≤8×10⁻⁶. -4 Ω·cm. High uniformity, manifested by resistivity differences of <8.0% at different locations on the target surface. Detailed Implementation

[0042] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0043] In a first aspect, some embodiments of the present invention provide an In4Sn3O 12 The method for preparing the target material includes the following steps:

[0044] S1: Using indium and tin as raw materials, a mixed metal salt solution is obtained by acid dissolution. The mixed metal salt solution is then added dropwise to ammonia water, causing indium hydroxide and tin hydroxide precipitates to form. After drying the indium hydroxide and tin hydroxide precipitates, a mixed powder is obtained and reacted at a higher temperature to obtain In4Sn3O. 12 Powder, In4Sn3O 12 Powder granulation yields granulated powder;

[0045] S2: The granulated powder is shaped using a mold to obtain a green body;

[0046] S3: Sintered green body, yielding In4Sn3O 12 Target material.

[0047] It is understood that this invention uses a co-precipitation method to first prepare In4Sn3O 12 The powder form simplifies the preparation process and improves the uniformity of indium-tin mixing. Organic acid activation of In4Sn3O is employed. 12 By lowering the sintering temperature, In4Sn3O powder with a density ≥99.2%, resistivity ≤8×10-4Ω·cm, and high uniformity can be obtained. 12 base target material.

[0048] It should be noted that although coprecipitation is a conventional powder-making process widely used in various fields, and many powders can be prepared by coprecipitation, the coprecipitation process and mechanism in this invention differ from existing coprecipitation methods due to the different material systems. In this invention, high homogeneity can be achieved by dissolving indium and tin in acid, while simplifying the process. The challenge of this invention lies in the order of precipitation of the mixed solution (Kc of In(OH)3 and Sn(OH)4). sp (Different), K sp The ionic equilibrium constant of a sparingly soluble substance (precipitate), also known as the solubility product, is equal to the product of the concentrations of cations and anions. When the product exceeds K... sp When precipitation occurs, a precipitate forms. For example, in this invention, both In(OH)3 and Sn(OH)4 are sparingly soluble in water, resulting in a precipitate, and a large amount of In is present in the solution. 3+ and Sn 4+ At this time, adding an alkaline solution provides OH-. - When OH- When the concentration exceeds a certain limit, In(OH)3 and Sn(OH)4 precipitates will appear.

[0049] It should also be noted that, due to the fact that both K sp There are differences; if the order of addition is reversed, towards In... 3+ and Sn 4+ Ammonia water is gradually added dropwise to the solution (to provide OH-). - At this point, because the cations are in excess, and OH... - The quantity is relatively small, therefore K sp Smaller hydroxides preferentially precipitate, leading to uneven precipitation (significant differences in chemical composition between different particles). That is, even if ammonia is gradually added dropwise to the mixed solution, uneven precipitation will still occur. Furthermore, sodium silicate is typically added as a dispersant during nanopowder preparation, but for TCO targets, silicon and sodium are highly detrimental impurities. This invention addresses this by gradually adding the mixed metal salt solution dropwise to ammonia, maintaining an excess of ammonia, and controlling the dropping rate. This ensures the uniformity of the added In. 3+ and Sn 4+ Precipitation was almost simultaneous and complete, avoiding uneven precipitation and improving the uniformity of indium-tin mixing, thus activating In4Sn3O. 12 The organic acids in the powder will volatilize during the high-temperature sintering of the target material, without introducing new impurities.

[0050] Furthermore, this invention does not have particularly high requirements for powder particle size, thereby simplifying the preparation process. Due to the low requirements for powder particle size, the synthesized In4Sn3O will be... 12 Powder can be finely ground by sand milling; it is simply a matter of refining the powder through physical methods.

[0051] It should also be noted that, in this invention, the target material matrix prepared is In4Sn3O. 12 It has a hexagonal crystal form, which is a completely different system from existing technologies such as Sn-doped In2O3.

[0052] The preparation method of the present invention does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are readily available, the production cost is low, and it is easy to industrialize.

[0053] In conjunction with the first aspect, in some embodiments of the present invention, in step S1, the mass fraction of indium in the indium and tin raw materials is 39.5% to 56.8%.

[0054] In indium and tin raw materials, the mass fraction of indium is 39.5% to 56.8%, which is considered low indium and significantly reduces costs.

[0055] In conjunction with the first aspect, in some embodiments of the present invention, in step S1, the acid includes concentrated nitric acid or concentrated hydrochloric acid.

[0056] In conjunction with the first aspect, in some embodiments of the present invention, the concentration of concentrated nitric acid is 50% to 65%.

[0057] Add nitric acid solution at 1.05-1.15 times the amount required to completely generate indium nitrate and tin nitrate, ensuring that the indium and tin metals can dissolve completely. After 2-5 hours of complete dissolution, a mixed metal salt solution is obtained.

[0058] In conjunction with the first aspect, in some embodiments of the present invention, the concentration of concentrated hydrochloric acid is 20% to 38%.

[0059] In conjunction with the first aspect, in some embodiments of the present invention, in step S1, the concentration of ammonia is 20% to 28%.

[0060] In conjunction with the first aspect, in some embodiments of the present invention, in step S1, the concentration of ammonia is any value of 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, or a range of any two, such as 24% to 26%.

[0061] In conjunction with the first aspect, in some embodiments of the present invention, the amount of ammonia water used is 1.08 to 1.20 times the amount required for all indium and tin to form metal salts.

[0062] In conjunction with the first aspect, in some embodiments of the present invention, the amount of ammonia used is any one of 1.08, 1.12, 1.14, 1.16, 1.18, or 1.20 times the amount required for all indium and tin to form metal salts, or a range of any two such as 1.14 to 1.18 times.

[0063] In conjunction with the first aspect, in some embodiments of the present invention, step S1 further includes adding 0.2wt% to 0.6wt% of polyvinylpyrrolidone as an organic dispersant to ammonia water to promote complete reaction. While forming indium hydroxide and tin hydroxide precipitates, ultrasonic dispersion is activated. After complete precipitation, the obtained indium hydroxide and tin hydroxide precipitates are centrifuged and washed to remove acid radical ions, and then spray-dried to obtain mixed powder.

[0064] In conjunction with the first aspect, in some embodiments of the present invention, the number of centrifugal washing cycles is 3 to 6.

[0065] In conjunction with the first aspect, in some embodiments of the present invention, in step S1, ammonia water can be placed in a stirring tank, an organic dispersant (0.2wt% to 0.6wt% of polyvinylpyrrolidone) can be added, and the stirring can be started at the same time as the ultrasound. The combined effect of the three can further improve the uniformity of the precipitation.

[0066] In conjunction with the first aspect, in some embodiments of the present invention, step S1, the heating reaction process includes: holding at 500℃~600℃ for 2h~8h, holding at 1000℃~1200℃ for 3h~8h, and holding at 1300℃~1500℃ for 1h~5h. Holding at multiple temperature ranges promotes a more thorough reaction.

[0067] In conjunction with the first aspect, in some embodiments of the present invention, in step S1, In4Sn3O 12 The process of powder activation and granulation via organic acid includes: activating In4Sn3O 12 After ball milling the powder in a sand mill for 6 to 10 hours, powder D is obtained. 90 For slurries with a particle size <100 nm, the slurry is transferred to a mixer, and organic acid is added to make the acid concentration in the slurry 0.3 mol / L to 1.2 mol / L. The mixture is stirred at a speed of 50 rpm to 120 rpm for 2 h to 8 h. Then, binder and plasticizer are added to the slurry and stirred. Finally, the mixture is spray-granulated to obtain granulated powder.

[0068] In conjunction with the first aspect, in some embodiments of the invention, the adhesive comprises 0.5-2.0 wt% PVA.

[0069] In conjunction with the first aspect, in some embodiments of the invention, the plasticizer comprises 0.2-1.0 wt% PEG.

[0070] In conjunction with the first aspect, in some embodiments of the present invention, the mixing time for adding the binder and plasticizer can be 1 hour to 3 hours.

[0071] In conjunction with the first aspect, in some embodiments of the present invention, the organic acid includes at least one of oxalic acid, acetic acid, citric acid, and tartaric acid.

[0072] On the one hand, the organic weak acid reacts with the powder surface, causing certain crystal planes to be preferentially corroded and destroyed, thus damaging the crystal structure and reducing the sintering activation energy; on the other hand, the organic acid salts generated in the reaction decompose at low temperature (<900℃) to form a glassy phase. The combined effect of these two aspects reduces the sintering temperature.

[0073] In conjunction with the first aspect, in some embodiments of the present invention, in step S2, the molding pressure of the mold is 100MPa to 180MPa, and after demolding, it is cold isostatically pressed at 150MPa to 220MPa for 20 to 60 minutes to obtain a blank.

[0074] In conjunction with the first aspect, in some embodiments of the present invention, step S3 includes the following steps: heating the green blank to 600°C to 800°C at a rate of 0.5 to 2°C / min and holding it at that temperature for 2 to 6 hours; then heating it to 1300°C to 1450°C at a rate of 1 to 3°C / min while simultaneously introducing oxygen at a rate of 5 L / min to 30 L / min and holding it at that temperature for 1 to 5 hours; after the holding period, holding it at 1150°C to 1300°C for 5 to 10 hours; and finally cooling it to room temperature at a rate of 1°C / min to 5°C / min.

[0075] In a second aspect, some embodiments of the present invention provide an In4Sn3O 12 The target material is prepared by the method of the first aspect of the present invention.

[0076] The In4Sn3O of the present invention 12 The target material has the characteristics of high density, low resistivity and high uniformity.

[0077] In conjunction with the second aspect, in some embodiments of the present invention, In4Sn3O 12 The target material has a density ≥99.2% and a resistivity ≤8×10⁻⁶. -4 Ω·cm. High uniformity, manifested by resistivity differences of <8.0% at different locations on the target surface.

[0078] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0079] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0080] Unless otherwise specified, "room temperature" in this invention means 25℃±5℃.

[0081] Unless otherwise specified, "about" in this invention means that the allowable error is within ±2%.

[0082] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0083] Example 1

[0084] An In4Sn3O was prepared 12 The target material, and the specific method are as follows:

[0085] S1: Using indium and tin as raw materials, a mixed metal salt solution is obtained by acid dissolution. The mixed metal salt solution is then added dropwise to ammonia water, causing indium hydroxide and tin hydroxide precipitates to form. After drying the indium hydroxide and tin hydroxide precipitates, a mixed powder is obtained and reacted at a higher temperature to obtain In4Sn3O. 12 Powder, In4Sn3O 12 Powder is activated by organic acid and then granulated to obtain granulated powder;

[0086] S2: The granulated powder is shaped using a mold to obtain a green body;

[0087] S3: Sintered green body, yielding In4Sn3O 12 Target material.

[0088] In step S1:

[0089] In the raw materials of metallic indium and metallic tin, indium accounts for 39.5% by mass and tin accounts for 60.5% by mass.

[0090] The acid is concentrated nitric acid, with a concentration of 60%.

[0091] The concentration of ammonia water is 24%, and the amount of ammonia water used is 1.15 times the amount required for all indium and tin to form metal salts.

[0092] Add 0.4 wt% polyvinylpyrrolidone to ammonia water to promote the complete reaction. While indium hydroxide and tin hydroxide precipitates are forming, ultrasonic dispersion is turned on. After complete precipitation, the obtained indium hydroxide and tin hydroxide precipitates are centrifuged and washed, and then spray-dried to obtain a mixed powder.

[0093] The heating reaction process includes: holding at 550℃ for 4 hours, holding at 1100℃ for 5 hours, and holding at 1400℃ for 3 hours. In4Sn3O 12 The process of powder activation and granulation via organic acid includes: activating In4Sn3O12 After ball milling the powder in a sand mill for 8 hours, powder D was obtained. 90 For slurries with a particle size <100 nm, the slurry is transferred to a mixer, citric acid is added to make the concentration of citric acid in the slurry 0.8 mol / L, and the mixture is stirred at 80 rpm for 5 h. Then, a binder and plasticizer are added to the slurry and stirred, followed by spray granulation to obtain granulated powder.

[0094] In step S2:

[0095] The molding pressure of the mold is 140MPa. After demolding, it is cold isostatically pressed at 180MPa for 40 minutes to obtain the green blank.

[0096] In step S3:

[0097] The sintering process includes: heating the green blank to 700℃ at a rate of 1.5℃ / min and holding it at that temperature for 4 hours; then heating it to 1360℃ at a rate of 2℃ / min while simultaneously introducing oxygen at a rate of 15L / min and holding it at that temperature for 4 hours; after holding at that temperature, holding it at 1200℃ for 8 hours; and finally cooling it to room temperature at a rate of 3℃ / min.

[0098] Examples 2 to 6

[0099] The difference from Example 1 is that the indium and tin contents in the raw materials are different, and the maximum sintering temperature in step S3 is different. See Table 1 for details.

[0100] Table 1. Raw material composition and maximum sintering temperature of the target material in the comparative examples and embodiments.

[0101]

[0102]

[0103] Comparative Example 1

[0104] The difference between Comparative Example 1 and Example 3 is that Comparative Example 1 uses indium oxide and tin oxide as raw materials, mixes them evenly, and then keeps them at multiple temperature ranges at one time. The subsequent sand milling, organic acid activation, molding, and sintering temperature regime are all the same as those in Example 3.

[0105] Comparative Example 2

[0106] The difference from Example 3 is that the precipitation method in Comparative Example 2 is as follows: ammonia water is gradually added dropwise into a mixed solution of indium nitrate and tin nitrate, and no dispersant is added or the ultrasonic process is turned on, while the rest of the process remains the same.

[0107] Comparative Example 3

[0108] The difference between Comparative Example 3 and Example 4 is that Comparative Example 3 did not use organic acid to activate In4Sn3O.12 The powder process remains the same for all other processes.

[0109] Test case

[0110] The density, average resistivity, and maximum resistivity difference rate of the target materials prepared in the examples and comparative examples were tested.

[0111] The density of the target material was tested using the Archimedes' displacement method, and the surface resistivity was tested using a four-probe resistivity meter. At least 10 test areas were used for each target material, and the average value was taken as the average resistivity. The difference between the maximum and minimum resistivity values ​​was taken as the maximum resistivity difference rate. The results are shown in Table 2.

[0112] Table 2 Density and resistivity of the Examples and Comparative Examples

[0113]

[0114]

[0115] As can be seen from the target material performance parameters of Examples 1-6 in Table 2, all targets have high density (≥99.2%) and low resistivity (≤8×10⁻⁶). -4 The target material has a resistivity of (Ω·cm) and the resistivity difference at different locations on the target surface is <8.0%, exhibiting high uniformity.

[0116] Compared to Example 3, Comparative Examples 1 and 2 have the same chemical composition of target materials and completely identical powder ball milling, granulation, and sintering processes. However, the prepared target materials have relatively lower density, higher resistivity, and poorer uniformity. This is mainly because Example 3 uses co-precipitation mixing, and ammonia water is always in excess during the precipitation process. The addition of dispersant and the activation of ultrasound, combined with the other three factors, result in better uniformity of indium tin ions during precipitation, leading to better densification of the target material during sintering and better uniformity in different regions of the target material.

[0117] Comparative Example 3 had the same target material chemical composition as Example 3, and the powder ball milling, granulation, and sintering processes were completely identical. However, the density of the prepared target material was significantly lower than that of Example 3. This was mainly because Example 3 used organic acid to activate In4Sn3O. 12 The powder reduces the activation energy of powder sintering and thus lowers the sintering temperature. Therefore, under the same sintering process, Example 3 has higher density, resulting in lower resistivity and better uniformity.

[0118] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An In4Sn3O 12 The method for preparing the target material is characterized in that, Includes the following steps: S1: Using indium and tin as raw materials, a mixed metal salt solution is obtained by dissolving them in concentrated nitric acid or concentrated hydrochloric acid. This mixed metal salt solution is then added dropwise to ammonia solution with a concentration of 20%–28%, the amount of ammonia solution being 1.08–1.20 times the amount required for the complete formation of the metal salt from indium and tin. 0.2 wt%–0.6 wt% polyvinylpyrrolidone is added to the ammonia solution to promote complete reaction. Ultrasonic dispersion is activated simultaneously with the formation of indium hydroxide and tin hydroxide precipitates. After complete precipitation, the obtained indium hydroxide and tin hydroxide precipitates are centrifuged and washed, then spray-dried to obtain a mixed powder, which is then subjected to a heating reaction. The heating reaction process includes: holding at 500℃–600℃ for 2–8 hours, at 1000℃–1200℃ for 3–8 hours, and at 1300℃–1500℃ for 1–5 hours to obtain In4Sn3O. 12 Powder, containing the In4Sn3O 12 The powder is activated and granulated using organic acids. The process includes: activating In4Sn3O 12 After ball milling the powder in a sand mill for 6 to 10 hours, powder D is obtained. 90 A slurry with a particle size <100 nm is transferred to a stirrer, and an organic acid is added to make the acid concentration in the slurry 0.3 mol / L~1.2 mol / L. The slurry is stirred at a speed of 50 rpm~120 rpm for 2 h~8 h. Then, a binder and plasticizer are added to the slurry and stirred. Subsequently, the slurry is spray granulated to obtain granulated powder. In the indium and tin raw materials, the mass fraction of indium is 39.5%~56.8%, and the organic acid includes at least one of oxalic acid, acetic acid, citric acid, and tartaric acid. S2: The granulated powder is formed by mold under a pressure of 100MPa~180MPa. After demolding, it is cold isostatically pressed at 150MPa~220MPa for 20min~60min to obtain a green body. S3: The raw blank is heated to 600℃~800℃ at a rate of 0.5~2℃ / min and held for 2h~6h. Then, it is heated to 1300℃~1450℃ at a rate of 1~3℃ / min, while oxygen is introduced at a rate of 5L / min~30L / min, and held for 1h~5h. After the holding period, it is held at 1150℃~1300℃ for 5h~10h. Finally, it is cooled to room temperature at a rate of 1℃ / min~5℃ / min to obtain the In4Sn3O. 12 Target material.

2. The preparation method according to claim 1, characterized in that, In step S1, the concentration of the concentrated nitric acid is 50% to 65%; and / or, the concentration of the concentrated hydrochloric acid is 20% to 38%.

3. An In4Sn3O 12 The target material is characterized in that, It is prepared by the preparation method described in claim 1 or 2.

4. The In4Sn3O according to claim 3 12 The target material is characterized in that, The In4Sn3O 12 The target material has a density ≥99.2% and a resistivity ≤8×10⁻⁶. -4 Ω·cm.

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