A method for determining oxide inclusions in high-purity aluminum

Abstract

The present invention relates to a method for determining oxide inclusions in high-purity aluminum, the method comprising the following steps: (1) taking a rod-shaped sample from a high-purity aluminum ingot, and then performing pretreatment and ultrasonic oscillation treatment to obtain a pretreated sample; (2) dissolving the pretreated sample obtained in step (1), filtering the aluminum solution obtained after constant volume using filter paper to obtain filter paper containing oxide inclusions, and then drying the solution; weighing the filter paper after drying and the filter paper before filtration, respectively, and calculating the difference; (3) scanning and detecting the filter paper after drying obtained in step (2) to obtain the type of oxide inclusions. The method provided by the present invention can perform quantitative and qualitative analysis on oxide inclusions, has high safety, is simple to operate, and does not introduce impurities.

Description

Technical Field

[0001] The present invention relates to the field of oxide detection in nonferrous metals, and in particular to a method for determining oxide inclusions in high-purity aluminum. Background Art

[0002] High-purity aluminum thin films, the primary conductor material for integrated circuits, offer advantages such as low resistivity, ease of deposition and etching, and mature processing techniques. However, the purity of the high-purity aluminum target significantly impacts the performance of the sputtered film. Excessive inclusions in the target can easily form particles on the wafer during sputtering, leading to interconnects or short circuits. Therefore, detecting inclusions in high-purity aluminum ingots is particularly important.

[0003] Traditional chemical methods for detecting and analyzing oxide inclusions in aluminum primarily employ metallographic methods and bromine-methanol dissolution. CN 108896339A discloses a method for preparing metallographic specimens, comprising the following steps: S1. Sampling: Samples are cut at the edge and center of the sample; S2. Mounting: The colloid is slowly channeled through galvanized iron wire into a mounting mold for solidification; S3. Polishing; S4. Polishing; S5. Etching: The metallographic inspection surface is etched with an etching solution. However, when metallographic methods are applied to aluminum specimens, silicon carbide and polishing paste easily embed into the aluminum matrix during the polishing process due to its relatively soft nature, resulting in inaccurate test results.

[0004] CN 102087207A discloses a method for determining the content of oxide inclusions in aluminum and aluminum alloys using a bromine-methanol method. The determination steps include: taking a sample, cleaning and drying it; placing it in a beaker filled with methanol, and adding liquid bromine in portions; filtering the solution, and washing the filter paper with methanol; placing the filter paper with the precipitate in a crucible for ashing, adding boric acid and anhydrous sodium carbonate, melting and cooling, adding hydrochloric acid until completely dissolved, and fixing the volume; diluting with water, adding p-nitrophenol, adjusting the color to yellow with ammonia water, and then adjusting the color to just fade with hydrochloric acid, then adding ascorbic acid, then adding a buffer solution, adding an aluminum reagent, fixing the volume with water, and performing colorimetry with a standard curve.

[0005] CN 112129603A discloses a method for detecting inclusions in aluminum and aluminum alloy melts. The method includes the following steps: S1: First, a small piece of the sample is cut from the sample to be tested, cleaned, and dried; S2: The aluminum sample is dissolved in an ethanol solution; S3: The ethanol solution obtained in S2 is filtered, and the filtered impurities are melted, water and hydrochloric acid are added, and the mixture is poured into a 100ml volumetric flask; S4: A nitrophenol indicator is added to the 100ml volumetric flask and color-adjusted. Finally, the type and content of the inclusions are determined based on color comparison. The bromine-methanol dissolution method uses volatile, toxic chemicals that are harmful to the human body and inconvenient to operate.

[0006] In view of the shortcomings of the existing technology, there is an urgent need to provide a determination method that is highly safe and does not introduce impurities. Summary of the Invention

[0007] The present invention aims to provide a method for determining oxide inclusions in high-purity aluminum. By pretreating and dissolving a high-purity aluminum sample and comparing the mass change of filter paper before and after filtration, the oxide inclusions can be quantitatively analyzed. By scanning detection, the oxide inclusions can be qualitatively analyzed. The determination method is highly safe and does not introduce impurities.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for determining oxide inclusions in high-purity aluminum, the method comprising the following steps:

[0010] (1) A rod-shaped sample is taken from a high-purity aluminum ingot, and then pretreated and ultrasonically vibrated to obtain a pretreated sample;

[0011] (2) dissolving the pretreated sample obtained in step (1), filtering the aluminum solution obtained after constant volume using filter paper to obtain filter paper containing oxide inclusions, and then drying the filter paper; weighing the mass of the filter paper after the drying treatment and the mass of the filter paper before the filtration and calculating the difference;

[0012] (3) The filter paper obtained after the drying treatment in step (2) is scanned and tested to obtain the type of the oxidized inclusions.

[0013] The present invention provides a method for determining oxide inclusions in high-purity aluminum. By pre-treating and ultrasonically oscillating the high-purity aluminum sample, impurities on the sample surface can be removed, facilitating subsequent processes. By performing a dissolution treatment to allow a chemical reaction between the sample and a reagent, and then comparing the mass change of the filter paper before and after filtration, the oxide inclusions can be quantitatively analyzed. Furthermore, by scanning detection, the oxide inclusions can be qualitatively analyzed. The determination method is highly safe, simple to operate, and does not introduce impurities.

[0014] Preferably, the diameter of the rod-shaped sample in step (1) is 9-11 mm, for example, 9 mm, 9.5 mm, 10 mm, 10.5 mm or 11 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, the length of the rod-shaped sample in step (1) is 14-16 mm, for example, 14 mm, 14.5 mm, 15 mm, 15.5 mm or 16 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] Preferably, the reagent used for the pretreatment in step (1) includes a hydrochloric acid solution.

[0017] Preferably, the hydrochloric acid solution comprises a mixed solution of pure water and hydrochloric acid with a concentration of 36-38%, for example, 36%, 37% or 38%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] Preferably, the volume ratio of pure water to hydrochloric acid is 1:(1.9-2.1), for example, it can be 1:1.9, 1:2 or 1:2.1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0019] Preferably, the pretreatment temperature in step (1) is 48-52°C, for example, 48°C, 49°C, 50°C, 51°C or 52°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the pretreatment time in step (1) is 25-35 min, for example, 25 min, 28 min, 30 min, 32 min or 35 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] The pretreatment step can effectively remove dirt and impurities on the surface of the rod-shaped sample, avoiding the introduction of impurities in subsequent processes and reducing purity; the pretreatment is carried out within a limited temperature range, which can also effectively improve the impurity removal effect.

[0022] Preferably, the ultrasonic oscillation treatment in step (1) is carried out in anhydrous ethanol.

[0023] Preferably, the time of the ultrasonic oscillation treatment in step (1) is 14-16 min, for example, it can be 14 min, 14.5 min, 15 min, 15.5 min or 16 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] The ultrasonic oscillation treatment can remove residual reagents and impurities on the surface of the rod-shaped sample, further improving the purity of the rod-shaped sample.

[0025] Preferably, the ultrasonic oscillation treatment in step (1) further includes the steps of drying and weighing.

[0026] Preferably, the reagent used for the dissolution treatment in step (2) includes a mixture of nitric acid and hydrochloric acid.

[0027] Preferably, the volume ratio of nitric acid to hydrochloric acid is 3:(1-2), for example, 3:1, 3:1.5 or 3:2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the mass volume ratio of the pretreated sample to the mixed liquid is (2-5) g:120 mL, for example, it can be 2 g:120 mL, 3 g:120 mL, 4 g:120 mL or 5 g:120 mL, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the dissolution treatment time in step (2) is 6-8 hours, for example, 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] The dissolution treatment time is within the specified range, which can allow the high-purity aluminum pretreatment sample to be completely dissolved in the mixed acid. If the time is too short, the dissolution will be incomplete, and if the time is too long, the degree of dissolution will not be further increased.

[0031] Preferably, the volume determination in step (2) is as follows: the solution obtained by the dissolution treatment is made to have a volume of 1000 mL using pure water.

[0032] Preferably, the pore size of the filter paper in step (2) is 0.2-20 μm, for example, 0.2 μm, 5 μm, 10 μm or 20 μm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] During the filtration process, filter papers with different pore sizes can be selected and filtered multiple times as needed to further separate oxide inclusions of different sizes. It should be noted that the change in mass of the filter paper before and after filtration is small compared to the mass of the filter paper. The content of oxide inclusions is measured and calculated using a precision balance, resulting in more accurate results.

[0034] Preferably, the scanning detection in step (2) is performed under a scanning electron microscope.

[0035] Preferably, the types of the oxide inclusions in step (2) include aluminum oxide and / or silicon dioxide.

[0036] The scanning detection can perform qualitative analysis of the substance and further obtain the specific types of oxide inclusions in the high-purity aluminum.

[0037] As a preferred technical solution of the determination method provided by the present invention, the determination method comprises the following steps:

[0038] (1) A rod-shaped sample with a diameter of 9-11 mm and a length of 14-16 mm was taken from a high-purity aluminum ingot, and then pretreated at 48-52° C. for 25-35 min and ultrasonically shaken in anhydrous ethanol for 14-16 min to obtain a pretreated sample;

[0039] The reagent used for the pretreatment includes a hydrochloric acid solution; the hydrochloric acid solution includes a mixed solution of pure water and hydrochloric acid with a concentration of 36-38%; the volume ratio of the pure water to the hydrochloric acid is 1:(1.9-2.1);

[0040] (2) The pretreated sample obtained in step (1) is dissolved for 6-8 hours, and the solution obtained by the dissolution treatment is fixed to 1000 mL with pure water. The obtained aluminum solution is filtered using filter paper with a pore size of 0.2-20 μm to obtain the filter paper containing oxide inclusions, and then dried; the mass of the filter paper after the drying treatment and the mass of the filter paper before the filtration are respectively weighed and the difference is calculated;

[0041] The reagent used for the dissolution treatment includes a mixture of nitric acid and hydrochloric acid; the volume ratio of the nitric acid to the hydrochloric acid is 3:(1-2); the mass volume ratio of the pretreated sample to the mixture is (2-5) g:120 mL;

[0042] (3) The filter paper obtained after drying in step (2) is scanned and examined under a scanning electron microscope to obtain the types of the oxidized inclusions.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention provides a method for determining oxide inclusions in high-purity aluminum. By pre-treating and ultrasonically oscillating the high-purity aluminum sample, impurities on the sample surface can be removed, facilitating subsequent processes. By performing a dissolution treatment to allow a chemical reaction between the sample and a reagent, and then comparing the mass change of the filter paper before and after filtration, the oxide inclusions can be quantitatively analyzed. Furthermore, by scanning detection, the oxide inclusions can be qualitatively analyzed. The determination method is highly safe, simple to operate, and does not introduce impurities. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a backscattered electron image of the oxide inclusions provided in Example 1 of the present invention;

[0046] Figure 2 This is a surface scanning diagram of the oxide inclusion elements provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0048] Example 1

[0049] This embodiment provides a method for determining oxide inclusions in high-purity aluminum, the method comprising the following steps:

[0050] (1) A rod-shaped sample with a diameter of 10 mm and a length of 15 mm was taken from a high-purity aluminum ingot, and then pretreated at 50°C for 30 min and ultrasonically shaken in anhydrous ethanol for 15 min to obtain a pretreated sample;

[0051] The reagent used for the pretreatment is a hydrochloric acid solution; the hydrochloric acid solution is a mixed solution of pure water and 37% hydrochloric acid; the volume ratio of the pure water to the hydrochloric acid is 1:2;

[0052] (2) The pretreated sample obtained in step (1) was dissolved for 7 hours, and the solution obtained by the dissolution treatment was fixed to 1000 mL with pure water. The obtained aluminum solution was filtered using filter paper with a pore size of 10 μm to obtain filter paper containing oxide inclusions, and then dried; the mass of the filter paper after the drying treatment and the mass of the filter paper before the filtration were weighed respectively and the difference was calculated to obtain the content of oxide inclusions of 0.005%;

[0053] The reagent used for the dissolution treatment is a mixture of nitric acid and hydrochloric acid; the volume ratio of the nitric acid to the hydrochloric acid is 3:2; the mass volume ratio of the pretreated sample to the mixture is 5g:120mL;

[0054] (3) The filter paper obtained after drying in step (2) was scanned and examined under a scanning electron microscope. Figure 1 and Figure 2 As shown in Figure 2, the oxide inclusions in high-purity aluminum are mainly aluminum oxide and silicon dioxide.

[0055] Example 2

[0056] This embodiment provides a method for determining oxide inclusions in high-purity aluminum, the method comprising the following steps:

[0057] (1) A rod-shaped sample with a diameter of 9 mm and a length of 14 mm was obtained from a high-purity aluminum ingot, and then pretreated at 48°C for 35 min and ultrasonically shaken in anhydrous ethanol for 14 min to obtain a pretreated sample;

[0058] The reagent used for the pretreatment is a hydrochloric acid solution; the hydrochloric acid solution is a mixed solution of pure water and 36% hydrochloric acid; the volume ratio of the pure water to the hydrochloric acid is 1:1.9;

[0059] (2) The pretreated sample obtained in step (1) was dissolved for 6 hours, and the solution obtained by the dissolution treatment was fixed to 1000 mL with pure water. The obtained aluminum solution was filtered using filter paper with a pore size of 0.2 μm to obtain filter paper containing oxide inclusions, and then dried. The mass of the filter paper after the drying treatment and the filter paper before the filtration were weighed and the difference was calculated to obtain the content of oxide inclusions of 0.0055%;

[0060] The reagent used for the dissolution treatment is a mixture of nitric acid and hydrochloric acid; the volume ratio of the nitric acid to the hydrochloric acid is 3:1; the mass volume ratio of the pretreated sample to the mixture is 3g:120mL;

[0061] (3) The filter paper obtained after drying in step (2) was scanned and examined under a scanning electron microscope, and the types of the oxide inclusions were found to be aluminum oxide and silicon dioxide.

[0062] Example 3

[0063] This embodiment provides a method for determining oxide inclusions in high-purity aluminum, the method comprising the following steps:

[0064] (1) A rod-shaped sample with a diameter of 9 mm and a length of 14 mm was obtained from a high-purity aluminum ingot, and then pretreated at 52°C for 25 min and ultrasonically shaken in anhydrous ethanol for 16 min to obtain a pretreated sample;

[0065] The reagent used for the pretreatment is a hydrochloric acid solution; the hydrochloric acid solution is a mixed solution of pure water and 38% hydrochloric acid; the volume ratio of the pure water to the hydrochloric acid is 1:2.1;

[0066] (2) The pretreated sample obtained in step (1) was dissolved for 8 h, and the solution obtained by the dissolution treatment was fixed to 1000 mL with pure water. The obtained aluminum solution was filtered using filter paper with a pore size of 20 μm to obtain filter paper containing oxide inclusions, and then dried. The mass of the filter paper after the drying treatment and the mass of the filter paper before the filtration were weighed and the difference was calculated to obtain the content of oxide inclusions of 0.0045%;

[0067] The reagent used for the dissolution treatment is a mixture of nitric acid and hydrochloric acid; the volume ratio of the nitric acid to the hydrochloric acid is 3:2; the mass volume ratio of the pretreated sample to the mixture is 2g:120mL;

[0068] (3) The filter paper obtained after drying in step (2) was scanned and examined under a scanning electron microscope, and the types of the oxide inclusions were found to be aluminum oxide and silicon dioxide.

[0069] Example 4

[0070] This embodiment provides a method for determining oxide inclusions in high-purity aluminum. The difference from Example 1 is that, except for adjusting the pretreatment temperature in step (1) to 40° C., the rest is the same as Example 1.

[0071] Since the pretreatment temperature is too low, the impurity removal effect on the surface of the rod sample is reduced, resulting in a higher content of measured oxide inclusions.

[0072] Example 5

[0073] This embodiment provides a method for determining oxide inclusions in high-purity aluminum. The difference from Example 1 is that the diameter of the rod-shaped sample in step (1) is adjusted to 11 mm and the length is adjusted to 16 mm. The rest is the same as Example 1.

[0074] As the sample size increases, the dissolution efficiency decreases, which has little effect on the measured content of oxide inclusions.

[0075] Example 6

[0076] This embodiment provides a method for determining oxide inclusions in high-purity aluminum. The difference from Example 1 is that the filtration in step (2) is: filtering is performed using filter papers with pore sizes of 20 μm, 10 μm, 5 μm, and 0.2 μm in sequence. The rest is the same as Example 1.

[0077] In this embodiment, filter papers with different pore sizes are used for multiple filtrations. Since oxide inclusions of different sizes are filtered out, the content of oxide inclusions calculated in Example 1 is higher, further improving the accuracy of the measured oxide inclusion content.

[0078] Comparative Example 1

[0079] This comparative example provides a method for determining oxide inclusions in high-purity aluminum. The difference from Example 1 is that the pretreatment described in step (1) is omitted, and the rest is the same as Example 1.

[0080] Due to the lack of pretreatment, there are more impurities on the surface of the rod sample, and the measured content of oxide inclusions is relatively high.

[0081] Comparative Example 2

[0082] This comparative example provides a method for determining oxide inclusions in high-purity aluminum. The difference from Example 1 is that the ultrasonic oscillation treatment in step (1) is replaced by a conventional ethanol cleaning treatment, and the rest is the same as Example 1.

[0083] Since the ultrasonic oscillation treatment was replaced by conventional ethanol cleaning treatment, there were reagent and impurity residues on the surface of the rod sample, and the measured content of oxide inclusions was relatively high.

[0084] In summary, the method for determining oxide inclusions in high-purity aluminum provided by the present invention can remove impurities on the surface of the sample by pretreating and ultrasonic oscillating the high-purity aluminum sample, which is beneficial to the subsequent process; by performing a dissolution treatment, a chemical reaction occurs between the sample and the reagent, and then comparing the mass change of the filter paper before and after filtration, the oxide inclusions can be quantitatively analyzed, and further, by scanning detection, the oxide inclusions can be qualitatively analyzed. The determination method is highly safe, simple to operate, and does not introduce impurities.

[0085] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for determining oxide inclusions in high-purity aluminum, characterized in that: The measuring method comprises the following steps: (1) A rod-shaped sample is taken from a high-purity aluminum ingot, and then pretreated and ultrasonically vibrated to obtain a pretreated sample; the reagent used for the pretreatment includes a hydrochloric acid solution; the hydrochloric acid solution includes a mixed solution of pure water and hydrochloric acid with a concentration of 36-38%; the volume ratio of the pure water to the hydrochloric acid is 1:(1.9-2.1); (2) The pretreated sample obtained in step (1) is dissolved for 6-8 hours, and the aluminum solution obtained after constant volume is filtered using filter paper to obtain filter paper containing oxide inclusions, and then dried; The mass of the filter paper after the drying treatment and the mass of the filter paper before filtration were respectively weighed and the difference was calculated; the reagent used for the dissolution treatment included a mixture of nitric acid and hydrochloric acid in a volume ratio of 3:(1-2); the mass volume ratio of the pretreated sample to the mixture was (2-5) g:120 mL; (3) The filter paper obtained after the drying treatment in step (2) is scanned and tested to obtain the types of the oxidized inclusions.

2. The measuring method according to claim 1, wherein The diameter of the rod-shaped sample in step (1) is 9-11 mm.

3. The measuring method according to claim 1, wherein The length of the rod-shaped sample in step (1) is 14-16 mm.

4. The measuring method according to claim 1, wherein The pretreatment temperature in step (1) is 48-52°C.

5. The measuring method according to claim 1, wherein The pretreatment time in step (1) is 25-35 minutes.

6. The measuring method according to claim 1, wherein The ultrasonic oscillation treatment in step (1) is carried out in anhydrous ethanol.

7. The measuring method according to claim 1, wherein The ultrasonic oscillation treatment time in step (1) is 14-16 minutes.

8. The measuring method according to claim 1, wherein The ultrasonic oscillation treatment in step (1) also includes the steps of drying and weighing.

9. The measuring method according to claim 1, wherein The volume determination in step (2) is as follows: the solution obtained by the dissolution treatment is made up to 1000 mL using pure water.

10. The measuring method according to claim 1, wherein The pore size of the filter paper in step (2) is 0.2-20 μm.

11. The measuring method according to claim 1, wherein The scanning detection in step (2) is performed under a scanning electron microscope.

12. The measuring method according to claim 1, wherein The types of the oxide inclusions in step (2) include aluminum oxide and / or silicon dioxide.

13. The measuring method according to claim 1, wherein The determination method comprises the following steps: (1) A rod-shaped sample with a diameter of 9-11 mm and a length of 14-16 mm was taken from a high-purity aluminum ingot, and then pretreated at 48-52°C for 25-35 min and ultrasonically oscillated in anhydrous ethanol for 14-16 min to obtain a pretreated sample; The reagent used for the pretreatment includes a hydrochloric acid solution; the hydrochloric acid solution includes a mixed solution of pure water and hydrochloric acid with a concentration of 36-38%; the volume ratio of the pure water to the hydrochloric acid is 1:(1.9-2.1); (2) The pretreated sample obtained in step (1) was dissolved for 6-8 hours, and the solution obtained by the dissolution treatment was fixed to 1000 mL with pure water. The obtained aluminum solution was filtered using filter paper with a pore size of 0.2-20 μm to obtain the filter paper containing oxide inclusions, and then dried; Weigh the mass of the filter paper after the drying treatment and the mass of the filter paper before filtration respectively and calculate the difference; The reagent used for the dissolution treatment includes a mixture of nitric acid and hydrochloric acid; the volume ratio of the nitric acid to the hydrochloric acid is 3:(1-2); the mass volume ratio of the pretreated sample to the mixture is (2-5) g:120 mL; (3) The filter paper obtained after drying in step (2) is scanned and inspected under a scanning electron microscope to obtain the types of the oxidized inclusions.

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