A tin oxide target and a method for producing the same

Abstract

The application belongs to the technical field of new materials, and discloses a preparation method of a tin oxide target material, which comprises the following steps: step 1, preparing a tin oxide precursor by using a precipitation method; step 2, calcining the tin oxide precursor under an inert atmosphere at a temperature of 300-400 DEG C to obtain tin oxide powder with a specific surface area of 35-38 m 2 / g; step 3, mixing the tin oxide powder obtained in step 2 with water and / or alcohol, and performing heat treatment on the mixture by using an autoclave to obtain tin oxide powder with a specific surface area of 30-33 m 2 / g; and step 4, placing the tin oxide powder obtained in step 3 in a mold, and performing pressure calcination on the tin oxide powder in a vacuum environment to obtain the tin oxide target material. The method adopts the precipitation method to prepare a precursor, performs pre-calcination on the precursor, and then performs solution heat treatment on the precursor, and finally prepares the target material, so that the segregation phenomenon is effectively reduced, the resistivity is reduced, the tin oxide powder rich in oxygen vacancy defects is obtained, and the tin oxide target material with low resistivity and high oxygen vacancy defects is obtained. Meanwhile, the application also provides the tin oxide target material prepared based on the method.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of new materials, in particular to a tin oxide target material and a preparation method thereof. BACKGROUND

[0002] In the prior art, the preparation of tin oxide target material generally adopts a mold pressing forming sintering method, such as CN118271082A, a preparation method of tin oxide zinc doped zirconium high-density target material, which discloses a preparation method of preparing tin oxide powder, zirconium oxide powder and zinc oxide powder into a mixed slurry, then sanding, granulating, forming, sintering to obtain a tin oxide zinc doped zirconium high-density target material, and the resistivity is 1.5 to 40 mΩ·cm.

[0003] If the resistivity is to be further reduced, the existing mold pressing forming sintering method is already quite difficult to use.

[0004] The technical problem solved by the present application is how to further reduce the resistivity. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of tin oxide target material, which adopts a precipitation method to prepare a precursor, pre-calcines the precursor and then performs solution method heat treatment, and finally prepares a target material, which effectively reduces the segregation phenomenon and in turn reduces the resistivity, obtains tin oxide powder rich in oxygen vacancy defects, and in turn obtains tin oxide target material with low resistivity and high oxygen vacancy defects.

[0006] Meanwhile, the present application also provides a tin oxide target material prepared based on the method.

[0007] To achieve the above purpose, the present application discloses:

[0008] A preparation method of tin oxide target material, comprising the following steps:

[0009] Step 1: adopting a precipitation method to prepare a tin oxide precursor;

[0010] Step 2: calcining the tin oxide precursor at 300-400℃ under an inert atmosphere to obtain tin oxide powder with a specific surface area of 35-38 m 2 / g;

[0011] Step 3: mixing the tin oxide powder obtained in step 2 with water and / or alcohol, and performing heat treatment with an autoclave to obtain tin oxide powder with a specific surface area of 30-33 m 2 / g;

[0012] Step 4: placing the tin oxide powder obtained in step 3 in a mold and performing pressure calcination under a vacuum environment to obtain a tin oxide target material.

[0013] The core innovation points of the present application are two:

[0014] 1. The method of pre-calcination before heat treatment, to obtain the specific surface area of 35-38m 2 / g of tin oxide powder, by pre-calcination can reduce segregation, reduce resistivity.

[0015] 2. By heat treatment of step 3, we found that can improve oxygen vacancy, reduce resistivity, to get rich in oxygen vacancy defects of tin oxide powder.

[0016] In the above preparation method, the specific method of step 1 is to adjust the pH value of the precursor solution containing soluble tin salt, so that the tin element is precipitated in the form of tin hydroxide, to obtain tin oxide precursor.

[0017] In the above preparation method, the concentration of tin ions in the precursor solution is 1.5mol / L-2.5mol / L;

[0018] The precursor solution also contains doped metal ions; the doped metal ions are one or more of niobium ions, tantalum ions, titanium ions, cerium ions, zirconium ions, zinc ions;

[0019] The molar ratio of tin ions to each kind of doped metal ions is 96-99.8:0.1-2.

[0020] Preferably, the precursor solution also contains zinc ions and tantalum ions; the molar ratio of tin ions, zinc ions and tantalum ions is 96-99.8:0.1-2:0.1-2.

[0021] Generally speaking, zinc ions are used in tin oxide target material, the role of zinc ions is to improve the density and stability of the target material; tin oxide target material can also use tantalum ions or other metal ions such as zirconium, which further improves the performance of the target material;

[0022] When there are zinc ions in the target material, if the traditional method is used, more obvious ZnSnO3 segregation will occur, and when the pre-calcination process is used, the segregation phenomenon is obviously inhibited, and the resistivity is further reduced.

[0023] In the above preparation method, the pH value of step 1 is 7.0-7.5, and the reaction time is 1-4h; the specific surface area of the tin oxide precursor is 75-80m 2 / g.

[0024] In the above preparation method, the tin oxide precursor is washed and dried before step 2.

[0025] In the preparation method, the step 2 is specifically: calcining the tin oxide precursor at 300-400 DEG C for 10-12 hours under nitrogen atmosphere to obtain tin oxide powder with a specific surface area of 35-38 m 2 / g.

[0026] In the preparation method, in the step 3, the tin oxide powder is mixed with water and / or alcohol to obtain a mixed solution, the solid content of the mixed solution is 50wt%-60wt%, the heat treatment time is 6-8 hours, and the heat treatment temperature is 150-200 DEG C.

[0027] In the preparation method, the alcohol is ethanol or ethylene glycol, the filling degree of the autoclave is 70%-80%, and the pressure of the autoclave is 0.6-0.8 MPa.

[0028] In the preparation method, in the step 4, the pressure is increased to 10-20 MPa, the calcination temperature is 1100 DEG C-1200 DEG C, and the heating rate is 1-2 DEG C / min.

[0029] In the step 4, after the pressure is increased to the maximum pressure and the temperature is increased to the highest temperature, the pressure and temperature are maintained for 6-10 hours.

[0030] Meanwhile, the application further discloses a tin oxide target prepared by the method.

[0031] The application has at least the following beneficial effects:

[0032] The application adopts the precipitation method to prepare the precursor, pre-calcines the precursor, then performs the solution method heat treatment, and finally prepares the target, so that the segregation phenomenon is effectively reduced, the resistivity is reduced, the tin oxide powder rich in oxygen vacancy defects is obtained, and the tin oxide target with low resistivity and high oxygen vacancy defects is obtained.

[0033] More specifically, the pre-calcination method is adopted before the heat treatment, the tin oxide powder with a specific surface area of 35-38 m 2 / g is obtained, the segregation is reduced through the pre-calcination, the resistivity is reduced, the oxygen vacancy is improved through the heat treatment in the step 3, and the tin oxide powder and target rich in oxygen vacancy defects are obtained. DETAILED DESCRIPTION

[0034] The application will be clearly and completely described below by combining with the embodiments of the application, and in the description of the application, it should be noted that the specific conditions are not indicated in the embodiments, and the conventional conditions or the conditions suggested by the manufacturers are adopted. The reagents or instruments are not indicated by the manufacturers, and are all conventional products that can be purchased in the market.

[0035] Embodiment 1

[0036] (1) Mix 9.96 L of 2.0 mol / L tin nitrate solution, 0.02 L of 2.0 mol / L zinc nitrate solution and 0.02 L of 2.0 mol / L tantalum nitrate solution, adjust the pH value to 7.2 by dropping ammonia water neutralizer, and react for 4 h. After the reaction is completed, perform solid-liquid separation, wash the separated solid phase with pure water, then dry at 80°C, grind, and obtain a tin oxide precursor with a BET of 78.11 m2 / g;

[0037] (2) Calcine the tin oxide precursor obtained in step (1) at 350°C in a nitrogen atmosphere for 11 h to obtain tin oxide powder I with a BET of 36.40 m2 / g;

[0038] (3) Add ethylene glycol to the tin oxide powder I obtained in step (2) to prepare a solution with a solid content of 55%, then add the solution to an autoclave, and make the filling degree of the autoclave 75%, the pressure in the autoclave 0.7 MPa, and perform centrifugal separation after heat treatment at 170°C for 7 h, then wash the precipitate with ethylene glycol, and dry at 80°C to obtain tin oxide powder II with a BET of 32.87 m2 / g;

[0039] (4) Put the tin oxide powder II obtained in step (3) into a mold, and then put it into a vacuum hot pressing furnace;

[0040] (5) Perform vacuumization on the vacuum hot pressing furnace, and when the vacuum degree reaches 10 Pa, heat it to 1150°C at a rate of 1.5°C / min, and simultaneously pressurize to 20 MPa, and keep the temperature and pressure for 8 h. Finally, when the temperature is less than 300°C, start depressurization, and after cooling to room temperature, take out the furnace to obtain a tin oxide target material with a relative density of 99.2%, a resistivity of 1.35 mΩ·cm, and an oxygen vacancy concentration of 7.87E+18 cm -3 .

[0041] Example 2

[0042] (1) Mix 9.8 L of 2.0 mol / L tin nitrate solution, 0.1 L of 2.0 mol / L zinc nitrate solution and 0.1 L of 2.0 mol / L tantalum nitrate solution, adjust the pH value to 7.3 by dropping ammonia water neutralizer, and react for 4 h. After the reaction is completed, perform solid-liquid separation, wash the separated solid phase with pure water, then dry at 80°C, grind, and obtain a tin oxide precursor with a BET of 77.52 m2 / g;

[0043] (2) Calcine the tin oxide precursor obtained in step (1) at 300°C in a nitrogen atmosphere for 12 h to obtain tin oxide powder I with a BET of 37.58 m2 / g;

[0044] (3) The tin oxide powder one obtained in step (2) is added into ethylene glycol to prepare a solution with a solid content of 55%, the solution is then added into an autoclave, the filling degree of the autoclave is 75%, the pressure in the autoclave is 0.7 MPa, and the obtained mixture is heated at 150°C for 8 hours, then centrifuged, and the precipitate is washed with ethylene glycol and dried at 80°C, thereby obtaining the tin oxide powder two with a BET of 34.04 m2 / g;

[0045] (4) The tin oxide powder two obtained in step (3) is loaded into a mold, and then the mold is placed into a vacuum hot pressing furnace;

[0046] (5) The vacuum hot pressing furnace is vacuumized, and then heated to 1100°C at a rate of 1.5°C / min, while the pressure is increased to 10 MPa, and the temperature and pressure are maintained for 8 hours, and then the pressure is released when the temperature is lower than 300°C, and the mold is taken out of the furnace when the temperature is lowered to room temperature, thereby obtaining the tin oxide target material with a relative density of 99.0%, a resistivity of 0.97 mΩ·cm, and an oxygen vacancy concentration of 7.14E+18 cm -3 .

[0047] Example 3

[0048] (1) 9.6 L of 2.0 mol / L tin nitrate solution, 0.2 L of 2.0 mol / L zinc nitrate solution and 0.2 L of 2.0 mol / L tantalum nitrate solution are mixed, the pH value is adjusted to 7.5 by adding ammonia water neutralizer, and the reaction is carried out for 4 hours, after the reaction is completed, the solid phase is separated by solid-liquid separation, washed with pure water, dried at 80°C, ground, and then a tin oxide precursor with a BET of 77.21 m2 / g is obtained;

[0049] (2) The tin oxide precursor obtained in step (1) is calcined at 400°C in a nitrogen atmosphere for 10 hours, thereby obtaining the tin oxide powder one with a BET of 35.38 m2 / g;

[0050] (3) The tin oxide powder one obtained in step (2) is added into ethylene glycol to prepare a solution with a solid content of 55%, the solution is then added into an autoclave, the filling degree of the autoclave is 75%, the pressure in the autoclave is 0.7 MPa, and the obtained mixture is heated at 200°C for 6 hours, then centrifuged, and the precipitate is washed with ethylene glycol and dried at 80°C, thereby obtaining the tin oxide powder two with a BET of 30.75 m2 / g;

[0051] (4) The tin oxide powder two obtained in step (3) is loaded into a mold, and then the mold is placed into a vacuum hot pressing furnace;

[0052] (5) The vacuum hot pressing furnace is vacuumized, and when the vacuum degree reaches 10 Pa, the temperature is raised to 1200°C at a rate of 1.5°C / min, and at the same time, the pressure is raised to 15 MPa, the temperature and pressure are maintained for 8 h, and finally, when the temperature is less than 300°C, the pressure is released, and after the temperature is lowered to room temperature, the furnace is discharged, and a tin oxide target with a relative density of 99.3%, an electrical resistivity of 1.14 mΩ.cm, and an oxygen vacancy concentration of 7.74E+18 cm -3 .

[0053] Example 4

[0054] (1) 9.8 L of 2.0 mol / L tin nitrate solution, 0.1 L of 2.0 mol / L zinc nitrate solution and 0.1 L of 2.0 mol / L tantalum nitrate solution are mixed, the pH value is adjusted to 7.3 by adding ammonia water neutralizer, and the reaction is carried out for 4 h. After the reaction is completed, the solid phase separated is washed with pure water, and then dried at 80°C and ground to obtain a tin oxide precursor with a BET of 77.64 m2 / g;

[0055] (2) The tin oxide precursor obtained in step (1) is calcined at 300°C in a nitrogen atmosphere for 12 h to obtain tin oxide powder I with a BET of 37.67 m2 / g;

[0056] (3) The tin oxide powder I obtained in step (2) is added to ethylene glycol to prepare a solution with a solid content of 55%, and then the solution is added to an autoclave with a filling degree of 75% and an internal pressure of 0.7 MPa. After heat treatment at 100°C for 19 h, centrifugal separation is carried out, and then the precipitate is washed with ethylene glycol, and then dried at 80°C to obtain tin oxide powder II with a BET of 34.08 m2 / g;

[0057] (4) The tin oxide powder II obtained in step (3) is loaded into a mold, and then placed in a vacuum hot pressing furnace;

[0058] (5) The vacuum hot pressing furnace is vacuumized, and when the vacuum degree reaches 10 Pa, the temperature is raised to 1200°C at a rate of 1.5°C / min, and at the same time, the pressure is raised to 15 MPa, the temperature and pressure are maintained for 8 h, and finally, when the temperature is less than 300°C, the pressure is released, and after the temperature is lowered to room temperature, the furnace is discharged, and a tin oxide target with a relative density of 99.3%, an electrical resistivity of 1.14 mΩ.cm, and an oxygen vacancy concentration of 7.74E+18 cm -3 .

[0059] Example 5

[0060] (1) 9.8 L of 2.0 mol / L tin nitrate solution, 0.1 L of 2.0 mol / L zinc nitrate solution and 0.1 L of 2.0 mol / L tantalum nitrate solution are mixed, the pH value is adjusted to 7.3 by dropping ammonia water neutralizer, and the reaction is carried out for 4 h. After the reaction is completed, the solid-liquid separation is carried out, the separated solid phase is washed with pure water, and then dried at 80°C and ground to obtain a tin oxide precursor with a BET of 77.38 m2 / g;

[0061] (2) The tin oxide precursor obtained in step (1) is calcined at 300°C in a nitrogen atmosphere for 12 h to obtain tin oxide powder I with a BET of 37.45 m2 / g;

[0062] (3) The tin oxide powder I obtained in step (2) is added into ethylene glycol to prepare a solution with a solid content of 55%, and then the solution is added into an autoclave with a filling degree of 75% and an internal pressure of 0.7 MPa. After heat treatment at 300°C for 4 h, centrifugal separation is carried out, and then the precipitate is washed with ethylene glycol and dried at 80°C to obtain tin oxide powder II with a BET of 33.84 m2 / g;

[0063] (4) The tin oxide powder II obtained in step (3) is loaded into a mold, and then placed into a vacuum hot pressing furnace;

[0064] (5) The vacuum hot pressing furnace is vacuumized to a vacuum degree of 10 Pa, and then heated to 1100°C at a rate of 1.5°C / min while pressurized to 10 MPa. The temperature and pressure are maintained for 8 h, and then the pressure is released when the temperature is lower than 300°C. After cooling to room temperature, the furnace is discharged to obtain a tin oxide target material with a relative density of 99.1%, a resistivity of 1.12 mΩ·cm and an oxygen vacancy concentration of 7.03E+18 cm -3 .

[0065] Comparative Example 1

[0066] (1) 9.96 L of 2.0 mol / L tin nitrate solution, 0.02 L of 2.0 mol / L zinc nitrate solution and 0.02 L of 2.0 mol / L tantalum nitrate solution are mixed, the pH value is adjusted to 7.2 by dropping ammonia water neutralizer, and the reaction is carried out for 4 h. After the reaction is completed, the solid-liquid separation is carried out, the separated solid phase is washed with pure water, and then dried at 80°C and ground to obtain a tin oxide precursor with a BET of 78.32 m2 / g;

[0067] (2) The tin oxide precursor obtained in step (1) is calcined at 350°C in a nitrogen atmosphere for 11 h to obtain tin oxide powder with a BET of 36.69 m2 / g;

[0068] (3) The tin oxide powder obtained in step (3) is loaded into a mold, and then placed into a vacuum hot pressing furnace;

[0069] (4) The vacuum hot pressing furnace is vacuumized, and after the vacuum degree reaches 10 Pa, the temperature is raised to 1150 °C at a rate of 1.5 °C / min, and at the same time, the pressure is increased to 20 MPa, and the holding time is 8 h. Finally, when the temperature is less than 300 °C, the pressure is released, and after the temperature is lowered to room temperature, the furnace is discharged, and a tin oxide target material with a relative density of 99.1%, a resistivity of 171.45 mΩ.cm, and an oxygen vacancy concentration of 4.87E+16 cm-3 is obtained.

[0070] Comparative Example 2

[0071] (1) 9.8 L of 2.0 mol / L tin nitrate solution, 0.1 L of 2.0 mol / L zinc nitrate solution, and 0.1 L of 2.0 mol / L tantalum nitrate solution are mixed, and the pH value is adjusted to 7.3 by adding ammonia water neutralizer, and the reaction is carried out for 4 h. After the reaction is completed, the solid phase is separated by solid-liquid separation, and the separated solid phase is washed with pure water, and then dried at 80 °C and ground to obtain a tin oxide precursor with a BET of 76.98 m2 / g;

[0072] (2) The tin oxide precursor obtained in step (1) is calcined at 300 °C in a nitrogen atmosphere for 12 h to obtain tin oxide powder I with a BET of 37.61 m2 / g;

[0073] (3) The tin oxide powder I obtained in step (2) is added to ethylene glycol to prepare a solution with a solid content of 55%, and then the solution is added to an autoclave with a filling degree of 75% and a pressure of 0.7 MPa. After heat treatment at 150 °C for 8 h, centrifugal separation is carried out, and then the precipitate is washed with ethylene glycol, and then dried at 80 °C to obtain tin oxide powder II with a BET of 34.56 m2 / g;

[0074] (4) The tin oxide powder II obtained in step (3) is loaded into a mold, and a target blank is obtained by cold isostatic pressing;

[0075] (5) The target blank is placed in a normal pressure sintering furnace, and the temperature is raised to 1100 °C at a rate of 1.5 °C / min, and the holding time is 8 h. Finally, after the temperature is lowered to room temperature, the furnace is discharged, and a tin oxide target material with a relative density of 91.6%, a resistivity of 1254.21 mΩ.cm, and an oxygen vacancy concentration of 7.68E+15 cm-3 is obtained.

[0076] Comparative Example 3

[0077] (1) mixed 9.6 L of 2.0 mol / L tin nitrate solution, 0.2 L of 2.0 mol / L zinc nitrate solution and 0.2 L of 2.0 mol / L tantalum nitrate solution, adjusted the pH value to 7.5 by dropping ammonia water neutralizer, and reacted for 4 h. After the reaction was completed, the solid phase separated was washed with pure water, and then dried at 80°C and ground to obtain a tin oxide precursor with a BET of 77.56 m2 / g;

[0078] (2) The tin oxide precursor obtained in step (1) was calcined at 400°C in an oxygen atmosphere for 10 h to obtain tin oxide powder I with a BET of 33.35 m2 / g;

[0079] (3) The tin oxide powder I obtained in step (2) was added into ethylene glycol to prepare a solution with a solid content of 55%, and then the solution was added into an autoclave with a filling degree of 75% and an internal pressure of 0.7 MPa. After heat treatment at 200°C for 6 h, centrifugal separation was performed, and then the precipitate was washed with ethylene glycol and dried at 80°C to obtain tin oxide powder II with a BET of 28.61 m2 / g;

[0080] (4) The tin oxide powder II obtained in step (3) was loaded into a mold, and then placed in a vacuum hot pressing furnace;

[0081] (5) The vacuum hot pressing furnace was vacuumed to a vacuum degree of 10 Pa, and then heated to 1200°C at a rate of 1.5°C / min while being pressurized to 15 MPa. The temperature and pressure were maintained for 8 h, and then the pressure was released when the temperature was less than 300°C. After cooling to room temperature, the furnace was discharged to obtain a tin oxide target material with a relative density of 99.3%, a resistivity of 110.58 Ω·cm and an oxygen vacancy concentration of 3.43E+10 cm-3.

[0082] Comparative Example 4

[0083] (1) mixed 9.8 L of 2.0 mol / L tin nitrate solution, 0.1 L of 2.0 mol / L zinc nitrate solution and 0.1 L of 2.0 mol / L tantalum nitrate solution, adjusted the pH value to 7.3 by dropping ammonia water neutralizer, and reacted for 4 h. After the reaction was completed, the solid phase separated was washed with pure water, and then dried at 80°C and ground to obtain a tin oxide precursor with a BET of 77.41 m2 / g;

[0084] (2) The tin oxide precursor obtained in step (1) was calcined at 200°C in a nitrogen atmosphere for 12 h to obtain tin oxide powder I with a BET of 53.82 m2 / g;

[0085] (3) The tin oxide powder one obtained in step (2) is added into ethylene glycol to prepare a solution with a solid content of 55%, the solution is then added into an autoclave, and the filling degree of the autoclave is 75%, after heat treatment at 150°C for 8h, centrifugal separation is performed, then the precipitate is washed with ethylene glycol, and then dried at 80°C, to obtain the tin oxide powder two with a BET of 50.37 m2 / g;

[0086] (4) The tin oxide powder two obtained in step (3) is loaded into a mold, and then placed into a vacuum hot pressing furnace;

[0087] (5) The vacuum hot pressing furnace is vacuumized, and after the vacuum degree reaches 10 Pa, the temperature is raised to 1100°C at a rate of 1.5°C / min, and the pressure is increased to 10 MPa, the holding time is 8h, and finally the pressure is released when the temperature is lower than 300°C, and after the temperature is lowered to room temperature, the furnace is discharged, to obtain the tin oxide target material with a relative density of 97.9%, a resistivity of 63.9 mΩ.cm, and an oxygen vacancy concentration of 9.76E+17 cm -3

[0088] Comparative Example 5

[0089] (1) 9.8 L of 2.0 mol / L tin nitrate solution, 0.1 L of 2.0 mol / L zinc nitrate solution and 0.1 L of 2.0 mol / L tantalum nitrate solution are mixed, the pH value is adjusted to 7.3 by adding ammonia water neutralizer, and the reaction is performed for 4h, after the reaction is completed, solid-liquid separation is performed, the solid phase separated is washed with pure water, and then dried at 80°C, ground and obtained the tin oxide precursor with a BET of 77.65 m2 / g;

[0090] (2) The tin oxide precursor obtained in step (1) is calcined at 600°C in a nitrogen atmosphere for 12h, to obtain the tin oxide powder one with a BET of 22.96 m2 / g;

[0091] (3) The tin oxide powder one obtained in step (2) is added into ethylene glycol to prepare a solution with a solid content of 55%, the solution is then added into an autoclave, and the filling degree of the autoclave is 75%, after heat treatment at 150°C for 8h, centrifugal separation is performed, then the precipitate is washed with ethylene glycol, and then dried at 80°C, to obtain the tin oxide powder two with a BET of 19.53 m2 / g;

[0092] (4) The tin oxide powder two obtained in step (3) is loaded into a mold, and then placed into a vacuum hot pressing furnace;

[0093] ​(5) The vacuum hot pressing furnace is vacuumized, and after the vacuum degree reaches 10 Pa, the temperature is raised to 1100°C at a rate of 1.5°C / min, and at the same time, the pressure is increased to 10 MPa, the holding time is 8 h, and finally, when the temperature is less than 300°C, the pressure is released, and after the temperature is lowered to room temperature, the furnace is discharged, and the relative density of the tin oxide target material is 94.6%, the resistivity is 7.04 Ω·cm, and the oxygen vacancy concentration is 6.43E+15 cm -3 .

[0094] Performance detection

[0095] The detection items include relative density, resistivity, and oxygen vacancy concentration.

[0096] The test method of the relative density is: relative density = density (drainage method) / true density (immersion method)

[0097] The test method of the resistivity is: four-probe method

[0098] The test method of the oxygen vacancy concentration is: chemical capacitance method

[0099] The detection results are shown in Table 1.

[0100] Table 1 Detection results

[0101] Case Relative density Resistivity Oxygen vacancy concentration Example 1 99.2％ 1.35 mΩ.cm 7.87E+18 cm -3 ]] Example 2 99.0％ 0.97 mΩ.cm 7.14E+18 cm -3 ]] Example 3 99.3％ 1.14 mΩ.cm 7.74E+18 cm -3 ]] Example 4 99.0％ 1.01 mΩ.cm 7.09E+18 cm -3 ]] Example 5 99.1％ 1.12 mΩ.cm 7.03E+18 cm -3 ]] Comparative Example 1 99.1％ 171.45 mΩ.cm 4.87E+16 cm -3 ]] Comparative Example 2 91.6％ 1254.21 mΩ.cm 7.68E+15 cm -3 ]] Comparative Example 3 99.3％ 110.58 Ω.cm 3.43E+10 cm -3 ]] Comparative Example 4 97.9％ 63.9 mΩ.cm 9.76E+17 cm -3 ]] Comparative Example 5 94.6％ 7.04 Ω.cm 6.43E+15 cm -3 ]]

[0102] Result analysis:

[0103] 1. It can be seen from Examples 1 to 5 that the method of pre-calcining combined with solution heat treatment can effectively reduce the resistivity and increase the oxygen vacancy. It can be seen from Examples 1 to 3 and Examples 4 and 5 that the solution heat treatment temperature has a slight effect on the oxygen vacancy concentration and the relative density, which is acceptable in process selection and product results.

[0104] 2. It can be seen from Example 1 and Comparative Example 1 that when the process of solution method heat treatment is not used, the resistivity is obviously increased and the oxygen vacancy concentration is significantly reduced; it can be seen from Example 2 and Comparative Example 2 that in the subsequent target material sintering process, the relative density is obviously increased and the resistivity is obviously reduced by using the vacuum pressure sintering method compared with the atmospheric pressure sintering method, and we believe that the vacuum pressure sintering method is more conducive to controlling the relative density, which is a direct factor affecting the resistivity; it can be seen from the comparison of Example 3 and Comparative Example 3 that when the precalcination atmosphere is changed to an oxygen atmosphere, the oxygen vacancy concentration is significantly reduced, and the reduction of the oxygen vacancy concentration leads to the increase of the electron material; in combination with Comparative Example 2 and Comparative Example 3, it can be seen that the influence of the relative density on the resistivity is much greater than the influence of the oxygen vacancy concentration on the resistivity; it can be seen from Comparative Example 4 and Comparative Example 5 that the precursor heating temperature is also a very critical process index, and too low temperature reduces the relative density, and too low temperature affects the oxygen vacancy concentration and the relative density; precalcination is mainly to change hydroxide into oxide, and too high temperature is easy to form zinc stannate (non-conductive) and rich oxygen will lead to excessive oxygen partial pressure, which inhibits the generation of oxygen vacancies. The increase of the oxygen vacancy concentration will lead to the decrease of the lattice constant and the volume, which is conducive to promoting carrier separation, and thus reducing the resistivity of the material.

[0105] It should be apparent to those skilled in the art that the application is not limited to the details of the foregoing illustrative examples, and that the present application can be carried out in other embodiments that are within the scope and spirit of the application. Therefore, from any point of view, the embodiments should be considered to be exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and scope of the equivalent elements of the claims.

Claims

1. A method for preparing a tin oxide target, characterized in that: The steps include: Step 1: preparing a tin oxide precursor by a precipitation method; Step 2: calcining the tin oxide precursor at 300-400°C in an inert atmosphere to obtain a tin oxide with a specific surface area of ​​35-38 m 2 / g of tin oxide powder; Step 3: Mix the tin oxide powder obtained in step 2 with water and / or alcohol, and heat-treat it in an autoclave to obtain a specific surface area of ​​30 to 33 m 2 / g of tin oxide powder; Step 4: Place the tin oxide powder obtained in step 3 in a mold and calcine it under pressure in a vacuum environment to obtain a tin oxide target.

2. The preparation method according to claim 1, characterized in that The specific method of step 1 is: adjusting the pH value of the precursor solution containing a soluble tin salt so that the tin element is precipitated in the form of tin hydroxide to obtain a tin oxide precursor.

3. The preparation method according to claim 2, characterized in that The concentration of tin ions in the precursor solution is 1.5 mol / L to 2.5 mol / L; The precursor solution further contains doping metal ions; the doping metal ions are one or more of niobium ions, tantalum ions, titanium ions, cerium ions, zirconium ions, and zinc ions; The molar ratio of the tin ions to each doping metal ion is 96-99.8:0.1-2.

4. The preparation method according to claim 2, characterized in that The pH value of step 1 is 7.0-7.5, and the reaction time is 1-4 hours; the specific surface area of ​​the tin oxide precursor is 75-80m 2 / g.

5. The preparation method according to claim 2, characterized in that Before step 2, the tin oxide precursor is washed and dried.

6. The preparation method according to claim 1, characterized in that The step 2 is specifically as follows: calcining the tin oxide precursor at 300-400° C. for 10-12 hours under a nitrogen atmosphere to obtain a tin oxide precursor having a specific surface area of ​​35-38 m 2 / g of tin oxide powder.

7. The preparation method according to claim 1, characterized in that In step 3, tin oxide powder and water and / or alcohol are mixed to obtain a mixed solution, wherein the solid content of the mixed solution is 50 wt% to 60 wt%; the heat treatment time is 6 to 8 hours; and the heat treatment temperature is 150 to 200°C.

8. The preparation method according to claim 1, characterized in that The alcohol is ethanol or ethylene glycol, the filling degree of the autoclave is 70% to 80%, and the pressure of the autoclave is 0.6 to 0.8 MPa.

9. The preparation method according to claim 1, characterized in that In step 4, the pressure is increased to 10-20 MPa; the calcination temperature is 1100° C. to 1200° C., and the heating rate is 1-2° C. / min; In the step 4, after pressurizing to the maximum pressure and heating to the highest temperature, the temperature and pressure are maintained for 6 to 10 hours.

10. A tin oxide target, characterized in that: The method is prepared by any one of claims 1 to 9.