A method for the preparation of yttria samples for detection by glow discharge mass spectrometry

Abstract

The application provides a preparation method of a yttrium oxide sample for glow discharge mass spectrometry detection, and the preparation method comprises the following steps: (1) an indium ingot is sequentially subjected to tabletting treatment, first acid washing, first water washing, first ethanol washing and first drying to obtain an indium tablet; (2) the yttrium oxide sample is placed in a container and sequentially subjected to second acid washing, second water washing, second ethanol washing and second drying to obtain a treated yttrium oxide sample; and (3) the treated yttrium oxide sample obtained in step (2) is embedded on the indium tablet obtained in step (1) to obtain a sample to be detected. The preparation method provided by the application avoids the introduction of impurities through the combination of a series of washing steps, can simply, quickly and accurately detect a plurality of impurity elements, does not cause the loss of matrix elements, and ensures the accuracy of data.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of analytical detection, and particularly relates to a preparation method of a yttrium oxide sample for glow discharge mass spectrometry detection. BACKGROUND

[0002] Rare earth nanomaterials are widely used in the fields of aviation, aerospace, electronic industry and the like. Yttrium oxide is an important raw material, has excellent corrosion resistance, high light transmittance and high dielectric constant, and is widely used in the fields of functional material such as transparent ceramic material and infrared material. Meanwhile, yttrium oxide has a high melting point and good heat resistance, and thus is widely concerned in the fields of refractory material, high-performance structural material, aerospace industry and the like. Generally, the purity of yttrium oxide material has an important influence on the performance of electronic products, and thus the detection and analysis of yttrium oxide material is very important.

[0003] There are many methods for detecting and analyzing yttrium oxide. In the existing method, the purity of yttrium oxide is determined by ICP-AES. However, when preparing a liquid sample, all impurity elements cannot be completely dissolved, and when the liquid contains a large amount of yttrium matrix, other impurity elements are easily disturbed, resulting in a decrease in the reliability of the detection result.

[0004] In recent decades, a glow discharge mass spectrometer (GDMS) has become the most powerful tool for rapid analysis of multiple elements in ultra-pure solid materials. It has superior detection limit and extremely wide linear dynamic range, and is widely used in the industries of conductors and semiconductors. Glow discharge mass spectrometry is an analysis method using a glow discharge source as an ion source and connecting with a mass spectrometer for mass spectrometry, and is mainly used for detecting the content of trace elements in a material. The corresponding analysis instrument is called a glow discharge mass spectrometer. A core component of the glow discharge mass spectrometer is a glow discharge chamber, which is used for the glow discharge of a sample to be detected, and ionizes neutral particles into an ion beam after sputtering.

[0005] In the process of detecting impurities by using a glow discharge mass spectrometer (GDMS), the impurities carried by the sample itself and easily mixed in the pressing process affect the detection result, and thus it is necessary to provide a sample preparation method to reduce the influence of impurities on the detection. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a preparation method of a yttrium oxide sample for glow discharge mass spectrometry detection. The preparation method provided by the present application avoids the introduction of impurities through a series of combined washing steps, can simply, quickly and accurately detect a plurality of impurity elements, does not cause the loss of matrix elements, and ensures the accuracy of the data.

[0007] To achieve the purpose, the present application adopts the following technical solutions:

[0008] The application provides a preparation method of a yttrium oxide sample for glow discharge mass spectrometry detection, and the preparation method comprises the following steps:

[0009] (1) an indium ingot is sequentially subjected to tabletting treatment, first acid washing, first water washing, first ethanol washing and first drying to obtain an indium tablet;

[0010] (2) a yttrium oxide sample is placed in a container and sequentially subjected to second acid washing, second water washing, second ethanol washing and second drying to obtain a treated yttrium oxide sample;

[0011] (3) the treated yttrium oxide sample obtained in step (2) is embedded on the indium tablet obtained in step (1) to obtain a sample to be detected;

[0012] Steps (1) and (2) have no sequence; the container in step (2) is a container subjected to cleaning treatment.

[0013] The application adopts different washing procedures according to the different chemical characteristics of the indium tablet and the yttrium oxide sample, can simultaneously avoid the introduction of impurities from the indium tablet and the yttrium oxide sample, simultaneously subjects the container to cleaning treatment, further avoids the introduction of impurities, and further ensures the accuracy of detection data.

[0014] As a preferred technical scheme of the application, the indium ingot in step (1) is a high-purity indium ingot.

[0015] Preferably, the purity of the high-purity indium ingot is ≥ 99.999 wt%, for example, can be 99.999%, 99.9992%, 99.9994%, 99.9996%, 99.9998% or 99.9999%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0016] As a preferred technical scheme of the application, the end point of the tabletting treatment in step (1) is that the thickness of the indium tablet is 1-3 mm, for example, can be 1 mm, 1.4 mm, 1.8 mm, 2.2 mm, 2.6 mm or 3 mm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0017] Preferably, the first acid washing in step (1) comprises washing 3-5 times with mixed acid solution A, for example, can be 3 times, 4 times or 5 times.

[0018] Preferably, the mixed acid solution A comprises nitric acid, hydrofluoric acid and water.

[0019] Preferably, the mass ratio of the nitric acid, the hydrofluoric acid and the water is 1:1:2-5, for example, it can be 1:1:2, 1:1:2.3, 1:1:2.6, 1:1:2.9, 1:1:3.2, 1:1:3.5, 1:1:3.8, 1:1:4.1, 1:1:4.4, 1:1:4.7 or 1:1:5, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0020] Preferably, the concentration of the nitric acid is 65-68wt%, for example, it can be 65wt%, 65.5wt%, 66wt%, 66.5wt%, 67wt%, 67.5wt% or 68wt%, but is not limited to the listed values, other values not listed in the value range are also applicable; the concentration of the hydrofluoric acid is 38-42wt%, for example, it can be 38wt%, 39wt%, 40wt%, 41wt% or 42wt%, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0021] It is worth noting that the present application uses mixed acid liquid A (a mixture of nitric acid and hydrofluoric acid) to clean the indium material, which not only speeds up the cleaning speed, but also removes other particles that are difficult to dissolve in nitric acid, further improving the purity of the sample.

[0022] As a preferred technical solution of the present application, the number of times of the first water washing in step (1) is 3-5, for example, it can be 3 times, 4 times or 5 times.

[0023] Preferably, the number of times of the first ethanol washing in step (1) is 3-5, for example, it can be 3 times, 4 times or 5 times.

[0024] Preferably, the first drying in step (1) includes drying treatment using an inert gas.

[0025] As a preferred technical solution of the present application, the second acid washing in step (2) includes ultrasonic cleaning of the yttrium oxide sample using mixed acid liquid B.

[0026] Preferably, the mixed acid liquid B includes nitric acid, hydrochloric acid and water.

[0027] Preferably, the mass ratio of the nitric acid, the hydrofluoric acid and the water is 1:1:2-5, for example, it can be 1:1:2, 1:1:2.3, 1:1:2.6, 1:1:2.9, 1:1:3.2, 1:1:3.5, 1:1:3.8, 1:1:4.1, 1:1:4.4, 1:1:4.7 or 1:1:5, but is not limited to the listed values, other values not listed in the value range are also applicable.

[0028] Preferably, the concentration of the nitric acid is 65-68 wt%, for example, it can be 65 wt%, 65.5 wt%, 66 wt%, 66.5 wt%, 67 wt%, 67.5 wt%, or 68 wt%, but is not limited to the listed values; other values ​​within the range that are not listed are also applicable. The concentration of the hydrochloric acid is 36-38 wt%, for example, it can be 36 wt%, 36.5 wt%, 37 wt%, 37.5 wt%, or 38 wt%, but is not limited to the listed values; other values ​​within the range that are not listed are also applicable.

[0029] Preferably, the time for each second pickling is 30 to 60 seconds, for example, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds or 60 seconds, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the second pickling is performed 3 to 5 times, for example, 3, 4 or 5 times.

[0031] It is worth noting that the present invention uses mixed acid solution B (a mixture of nitric acid and hydrochloric acid) to clean yttrium oxide materials, which can effectively avoid the shortcomings of cleaning materials with a single acid solution, speed up the cleaning process, and save time and costs.

[0032] As a preferred technical solution of the present invention, the number of times the second water washing is performed in step (2) is ≥3 times, for example, it can be 3 times, 4 times, 5 times or 6 times, but is not limited to the listed values. Other unlisted values ​​within the value range are also applicable.

[0033] Preferably, in step (2), the second ethanol wash is performed ≥ 3 times, for example, 3 times, 4 times, 5 times or 6 times, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, step (2) the second drying includes baking or purging drying.

[0035] Preferably, the purging and drying includes: drying with high-purity inert gas or drying with a CDA device.

[0036] Preferably, the drying process includes baking with an infrared lamp for 3 to 5 minutes, for example, 3 minutes, 3.4 minutes, 3.8 minutes, 4.2 minutes, 4.6 minutes or 5 minutes, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] As a preferred technical solution of the present invention, the embedding in step (3) includes: embedding the processed yttrium oxide sample onto an indium sheet using a tablet press.

[0038] Preferably, the pressing pressure in step (3) is 5 to 10 kPa, for example, it can be 5 kPa, 6 kPa, 7 kPa, 8 kPa, 9 kPa or 10 kPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] As a preferred embodiment of the present invention, the material of the container includes PTFE or PFA.

[0040] As a preferred embodiment of the present invention, the cleaning process includes: sequentially performing a first immersion wash, a first rinse, a second immersion wash, a second rinse, an ethanol rinse, and a drying process to obtain a cleaned container.

[0041] As a preferred embodiment of the present invention, the first immersion includes: immersing the container in a mixed acid solution A for cleaning.

[0042] Preferably, the soaking time is ≥1 hour, for example, it can be 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] It is worth noting that the mixed acid solution A used in the first immersion wash of the present invention is the same as the mixed acid solution A used in the first acid wash, both being a mixed solution of nitric acid, hydrofluoric acid and water in a mass ratio of 1:1:4.

[0044] Preferably, the secondary rinsing includes immersing the container in a mixed acid solution B or aqua regia for cleaning.

[0045] Preferably, the time for the second soaking is ≥1 hour, for example, it can be 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] It is worth noting that the mixed acid solution B used in the first immersion wash of the present invention is the same as the mixed acid solution B used in the second acid wash, both being a mixed solution of nitric acid, hydrochloric acid and water with a mass ratio of 1:1:4.

[0047] Preferably, the number of secondary rinsing cycles is 3 to 5, for example, 3, 4 or 5 times.

[0048] Preferably, the ethanol rinsing is performed 3 to 5 times, for example, 3, 4 or 5 times.

[0049] It is worth noting that the cleaning process described in this invention first uses mixed acid solution A to wash away other metallic impurities on the container surface, followed by a rinse to remove residual acid and dust; then, mixed acid solution B is used to wash away any fluoride ions that may remain in mixed acid solution A, followed by a second rinse to remove residual acid. Ethanol rinsing reduces surface moisture and shortens the drying time. This washing procedure efficiently removes various impurities from the container and avoids introducing impurities during the washing of yttrium oxide materials.

[0050] As a preferred embodiment of the present invention, the method for preparing yttrium oxide samples for detection by glow discharge mass spectrometry provided by the present invention includes the following steps:

[0051] (1) High-purity indium ingots with a purity ≥ 99.999 wt% are pressed into sheets with a thickness of 1-3 mm, subjected to first pickling 3-5 times, first water washing 3-5 times, first ethanol washing 3-5 times, and first drying to obtain indium sheets;

[0052] The acid used in the first pickling is nitric acid, hydrofluoric acid and water in a mass ratio of 1:1:4; the concentration of the nitric acid is 65-68 wt% and the concentration of the hydrofluoric acid is 38-42 wt%.

[0053] (2) The yttrium oxide sample was placed in a container and subjected to a second acid wash 3 to 5 times, a second water wash 3 times, a second ethanol wash 3 times, and a second drying to obtain the treated yttrium oxide sample.

[0054] The second pickling process uses nitric acid, hydrochloric acid, and water in a mass ratio of 1:1:4; the concentration of the nitric acid is 65-68 wt%, and the concentration of the hydrochloric acid is 36-38 wt%; the duration of each second pickling is 30-60 seconds.

[0055] The container is a cleaned container; the cleaning process includes: a first soaking, a first rinsing, a second soaking, a second rinsing 3 to 5 times, an ethanol rinsing 3 to 5 times, and a drying process.

[0056] The first immersion rinsing involves immersing the container in mixed acid solution A for cleaning for at least 1 hour; the second immersion rinsing involves immersing the container in mixed acid solution B or aqua regia for cleaning for at least 1 hour.

[0057] (3) Press the yttrium oxide sample obtained in step (2) onto the indium sheet obtained in step (1) to obtain the sample to be tested;

[0058] The pressing pressure is 5-10 kPa;

[0059] Steps (1) and (2) are not in any particular order.

[0060] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] (1) The method for preparing yttrium oxide samples for glow discharge mass spectrometry provided by the present invention can ensure that contamination is minimized during sample preparation, thereby enabling successful analysis of impurity elements in yttrium oxide materials and ensuring the accuracy of the data;

[0063] (2) The method for preparing yttrium oxide samples for glow discharge mass spectrometry provided by the present invention has a better washing effect by using different washing methods for indium sheets and yttrium oxide materials, taking into account the characteristics of the two. Detailed Implementation

[0064] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0065] Example 1

[0066] This embodiment provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry, the preparation method comprising the following steps:

[0067] (1) A high-purity indium ingot with a purity of 99.9999 wt% was pressed into a sheet with a thickness of 2 mm, subjected to four acid washes, four water washes, four ethanol washes, and a first drying process to obtain an indium sheet.

[0068] The acid used in the first pickling process is nitric acid, hydrofluoric acid, and water in a mass ratio of 1:1:4; the concentration of the nitric acid is 66 wt%, and the concentration of the hydrofluoric acid is 40 wt%.

[0069] (2) The yttrium oxide sample was placed in a container and subjected to four second acid washes, four second water washes, four second ethanol washes, and a second drying to obtain the treated yttrium oxide sample.

[0070] The second pickling process uses nitric acid, hydrochloric acid, and water in a mass ratio of 1:1:4; the concentration of the nitric acid is 66 wt%, and the concentration of the hydrochloric acid is 37 wt%; the duration of each second pickling is 45 seconds.

[0071] The container is a cleaned container; the cleaning process includes: a first soaking, a first rinsing, a second soaking, a second rinsing four times, an ethanol rinsing four times, and a drying process.

[0072] The first immersion wash consists of immersing the container in a mixed acid solution A (nitric acid, hydrofluoric acid, and water in a mass ratio of 1:1:4) for 1.5 hours; the second immersion wash consists of immersing the container in a mixed acid solution B (nitric acid, hydrochloric acid, and water in a mass ratio of 1:1:4) for 1.5 hours.

[0073] (3) The yttrium oxide sample obtained in step (2) is pressed onto the indium sheet obtained in step (1) to obtain the sample to be tested; wherein the pressing pressure is 8 kPa;

[0074] Steps (1) and (2) are not in any particular order.

[0075] Example 2

[0076] This embodiment provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry, the preparation method comprising the following steps:

[0077] (1) A high-purity indium ingot with a purity of 99.9995wt% was pressed into a sheet with a thickness of 1mm, subjected to three first acid washes, three first water washes, three first ethanol washes, and a first drying process to obtain an indium sheet.

[0078] The acid used in the first pickling process is nitric acid, hydrofluoric acid, and water in a mass ratio of 1:1:4; the concentration of the nitric acid is 65 wt%, and the concentration of the hydrofluoric acid is 38 wt%.

[0079] (2) The yttrium oxide sample was placed in a container and subjected to three second acid washes, three second water washes, three second ethanol washes, and a second drying to obtain the treated yttrium oxide sample.

[0080] The second pickling process uses nitric acid, hydrochloric acid, and water in a mass ratio of 1:1:4; the concentration of the nitric acid is 65 wt%, and the concentration of the hydrochloric acid is 36 wt%; the duration of each second pickling is 60 seconds.

[0081] The container is a cleaned container; the cleaning process includes: a first soaking, a first rinsing, a second soaking, a second rinsing three times, an ethanol rinsing three times, and a drying process.

[0082] The first immersion is performed by immersing the container in a mixed acid solution A (nitric acid, hydrofluoric acid, and water in a mass ratio of 1:1:4) for 2 hours; the second immersion is performed by immersing the container in aqua regia for 1 hour.

[0083] (3) The yttrium oxide sample obtained in step (2) is pressed onto the indium sheet obtained in step (1) to obtain the sample to be tested; the pressing pressure is 5 to 10 kPa;

[0084] Steps (1) and (2) are not in any particular order.

[0085] Example 3

[0086] This embodiment provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry, the preparation method comprising the following steps:

[0087] (1) A high-purity indium ingot with a purity of 99.999 wt% was pressed into a sheet with a thickness of 3 mm, subjected to five first pickling, five first water washing, five first ethanol washing, and a first drying process to obtain an indium sheet.

[0088] The acid used in the first pickling process is nitric acid, hydrofluoric acid, and water in a mass ratio of 1:1:4; the concentration of the nitric acid is 68 wt%, and the concentration of the hydrofluoric acid is 42 wt%.

[0089] (2) The yttrium oxide sample was placed in a container and subjected to a second acid wash 5 times, a second water wash 5 times, a second ethanol wash 5 times, and a second drying to obtain the treated yttrium oxide sample.

[0090] The second pickling process uses nitric acid, hydrochloric acid, and water in a mass ratio of 1:1:4; the concentration of the nitric acid is 68 wt%, and the concentration of the hydrochloric acid is 38 wt%; the duration of each second pickling is 30–60 seconds.

[0091] The container is a cleaned container; the cleaning process includes: a first soaking, a first rinsing, a second soaking, a second rinsing 3 to 5 times, an ethanol rinsing 3 to 5 times, and a drying process.

[0092] The first immersion wash consists of immersing the container in a mixed acid solution A (nitric acid, hydrofluoric acid, and water in a mass ratio of 1:1:4) for 2.1 hours; the second immersion wash consists of immersing the container in a mixed acid solution B (nitric acid, hydrochloric acid, and water in a mass ratio of 1:1:4) for 1.5 hours.

[0093] (3) The yttrium oxide sample obtained in step (2) is pressed onto the indium sheet obtained in step (1) to obtain the sample to be tested; the pressing pressure is 5 to 10 kPa;

[0094] Steps (1) and (2) are not in any particular order.

[0095] Example 4

[0096] This embodiment provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry. The only difference between this method and Example 1 is that:

[0097] In this embodiment, the acid used in the first pickling step (1) is changed to mixed acid solution B, that is, it is modified to be the same mixed acid solution as the second pickling step.

[0098] Example 5

[0099] This embodiment provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry. The only difference between this method and Example 1 is that:

[0100] In this embodiment, the acid used in the second pickling step (2) will be changed to mixed acid solution B, that is, it will be modified to be the same mixed acid solution as the first pickling.

[0101] Example 6

[0102] This embodiment provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry. The only difference between this method and Example 1 is that:

[0103] In this embodiment, the acid used in the first pickling in step (1) and the second pickling in step (2) is modified to nitric acid with a concentration of 66wt%.

[0104] Example 7

[0105] This embodiment provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry. The only difference between this method and Example 1 is that:

[0106] In this embodiment, the acid used in the first pickling step (1) is modified to hydrofluoric acid with a concentration of 40wt%.

[0107] Example 8

[0108] This embodiment provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry. The only difference between this method and Example 1 is that:

[0109] In this embodiment, the acid used in the second pickling step (2) is modified to hydrochloric acid with a concentration of 37wt%.

[0110] Comparative Example 1

[0111] This comparative example provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry. The only difference between this method and Example 1 is that:

[0112] This comparative example omits the cleaning process of the container in step (2).

[0113] Comparative Example 2

[0114] This comparative example provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry. The only difference between this method and Example 1 is that:

[0115] This comparative example omits step (1), the first pickling process.

[0116] Comparative Example 3

[0117] This comparative example provides a method for preparing a yttrium oxide sample for detection by glow discharge mass spectrometry. The only difference between this method and Example 1 is that:

[0118] This comparative example omits step (2), the second pickling process.

[0119] Application examples

[0120] The yttrium oxide samples provided in the above embodiments and comparative examples were subjected to glow discharge mass spectrometry testing. The testing method included: fixing the sample to be tested with a sample clamp, placing it in the sample chamber, waiting for the temperature in the glow discharge chamber to drop to about -180°C, opening the valve and pushing in the sample, and using the following test parameters: voltage 1.5kV, current 0.8mA, and appropriately adjusting the instrument resolution to 3800-4000. Sputtering tests were then performed to measure the impurity data in the yttrium oxide sample.

[0121] The analysis time and the maximum relative error of the test repeated 5 times using the above method are shown in Table 1.

[0122] Table 1

[0123] Analysis time / min Maximum relative error of the test repeated 5 times / % Example 1 60 10 Example 2 60 15 Example 3 60 18 Example 4 60 21 Example 5 60 23 Example 6 60 36 Example 7 60 38 Example 8 60 43 Comparative Example 1 90 51 Comparative Example 2 90 47 Comparative Example 3 90 55

[0124] Analysis of Table 1 reveals the following points:

[0125] (1) As can be seen from the comprehensive analysis of Examples 1-3, the sample preparation method provided by the present invention can ensure that no contamination is introduced during the sample preparation process, thereby successfully analyzing the impurity elements of yttrium oxide materials, ensuring the accuracy of the data, and keeping the maximum relative error of 5 repetitions within 20%.

[0126] (2) Comprehensive analysis of Examples 1 and Examples 4-8 shows that using mixed acid cleaning can effectively reduce impurity contamination during sample preparation, while using only one acid for cleaning will introduce contaminants and prolong the analysis time.

[0127] The applicant declares that the detailed process equipment and process flow of this invention are illustrated through the above embodiments, but this invention is not limited to the above detailed process equipment and process flow, that is, it does not mean that this invention must rely on the above detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, additions of auxiliary components, and selection of specific methods, all fall within the protection scope and disclosure scope of this invention.

Claims

1. A method for preparing yttrium oxide samples for detection by glow discharge mass spectrometry, characterized in that, The preparation method includes the following steps: (1) Indium ingots are subjected to pressing, first acid washing, first water washing, first ethanol washing and first drying in sequence to obtain indium sheets; the first acid washing includes washing with mixed acid solution A 3 to 5 times; the mixed acid solution A includes nitric acid, hydrofluoric acid and water in a mass ratio of 1:1:2 to 5; (2) The yttrium oxide sample is placed in a container and subjected to a second acid wash, a second water wash, a second ethanol wash, and a second drying in sequence to obtain the treated yttrium oxide sample; the second acid wash includes ultrasonic cleaning of the yttrium oxide sample with mixed acid solution B; the mixed acid solution B includes nitric acid, hydrochloric acid and water in a mass ratio of 1:1:2~5; (3) Press the yttrium oxide sample obtained in step (2) onto the indium sheet obtained in step (1) to obtain the sample to be tested; Steps (1) and (2) are not in any particular order; the container mentioned in step (2) is a cleaned container.

2. The preparation method according to claim 1, characterized in that, The indium ingot mentioned in step (1) is a high-purity indium ingot.

3. The preparation method according to claim 2, characterized in that, The purity of the high-purity indium ingot is ≥99.999 wt%.

4. The preparation method according to claim 1, characterized in that, The endpoint of the pressing process in step (1) is that the thickness of the indium sheet is 1~3mm.

5. The preparation method according to claim 1, characterized in that, The concentration of nitric acid in step (1) is 65~68wt%, and the concentration of hydrofluoric acid is 38~42wt%.

6. The preparation method according to claim 1, characterized in that, Step (1) The first water wash is performed 3 to 5 times.

7. The preparation method according to claim 1, characterized in that, Step (1) The first ethanol wash is performed 3 to 5 times.

8. The preparation method according to claim 1, characterized in that, Step (1) The first drying process includes drying with an inert gas.

9. The preparation method according to claim 1, characterized in that, The concentration of nitric acid in step (2) is 65-68 wt%, and the concentration of hydrochloric acid is 36-38 wt%.

10. The preparation method according to claim 1, characterized in that, The time for each second pickling is 30-60 seconds.

11. The preparation method according to claim 1, characterized in that, The second pickling process is repeated 3 to 5 times.

12. The preparation method according to any one of claims 1-5, characterized in that, Step (2) The second water wash is performed ≥ 3 times.

13. The preparation method according to claim 1, characterized in that, Step (2) The second ethanol wash is performed ≥ 3 times.

14. The preparation method according to claim 1, characterized in that, Step (2) The second drying includes baking or purging drying.

15. The preparation method according to claim 14, characterized in that, The drying process includes baking with infrared lamps for 3-5 minutes.

16. The preparation method according to claim 1, characterized in that, Step (3) includes embedding the processed yttrium oxide sample onto an indium sheet using a tablet press.

17. The preparation method according to claim 1, characterized in that, The pressure for pressing in step (3) is 5~10 kPa.

18. The preparation method according to claim 1, characterized in that, The container is made of PTFE or PFA.

19. The preparation method according to claim 1, characterized in that, The cleaning process includes: a first immersion, a first rinse, a second immersion, a second rinse, an ethanol rinse, and a drying process, in sequence, to obtain a cleaned container.

20. The preparation method according to claim 19, characterized in that, The first immersion includes: immersing the container in a mixed acid solution A for cleaning.

21. The preparation method according to claim 19, characterized in that, The soaking time for each soaking is ≥1 hour.

22. The preparation method according to claim 19, characterized in that, The secondary rinsing includes immersing the container in a mixed acid solution B or aqua regia for cleaning.

23. The preparation method according to claim 19, characterized in that, The second immersion time is ≥1 hour.

24. The preparation method according to claim 19, characterized in that, The secondary rinsing is performed 3 to 5 times.

25. The preparation method according to claim 19, characterized in that, The ethanol rinsing is performed 3 to 5 times.