A sample preparation method for silicon nitride analysis using ICP-OES
By using a composite acid solution of concentrated nitric acid, hydrofluoric acid, and concentrated sulfuric acid to microwave digest silicon nitride, the problems of large reagent consumption, long time, and large deviation in the detection of elemental content in silicon nitride in the existing technology are solved, and rapid and accurate detection results are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KONFOONG MATERIALS INTERNATIONAL CO LTD
- Filing Date
- 2024-10-25
- Publication Date
- 2026-05-26
Smart Images
Figure BDA0005103140010000081 
Figure BDA0005103140010000091
Abstract
Description
Technical Field
[0001] This invention belongs to the field of analytical testing technology and relates to a sample preparation method for silicon nitride for ICP-OES analysis. Background Technology
[0002] Silicon nitride is an important structural ceramic material. It is an ultra-hard substance, inherently lubricating and wear-resistant, an atomic crystal, and exhibits oxidation resistance at high temperatures. Silicon nitride is an ultra-hard, insoluble substance with inherent lubricity and wear resistance. The proportions of various elements in silicon nitride have a significant impact on its properties.
[0003] CN118329821A discloses a method for identifying and testing the lattice oxygen content of silicon nitride materials. The method for identifying and testing the lattice oxygen content of silicon nitride materials includes: (1) introducing helium and argon into a nitrogen-oxygen analyzer as the working carrier gas and driving gas for oxygen-nitrogen testing, respectively; (2) placing silicon nitride material powder in a graphite crucible, and using a nitrogen-oxygen analyzer under a stepped power heating reaction stage, according to the set analytical parameters, determining the oxygen and nitrogen content released by the silicon nitride material powder by infrared absorption spectroscopy and thermal conductivity method, respectively.
[0004] CN118343689A discloses a high-purity silicon nitride powder and its preparation method, which uses methods such as gravimetric method, titration method, atomic absorption spectrometry, and X-ray fluorescence spectrometry to detect the carbon and oxygen content in the silicon nitride powder.
[0005] The above-mentioned method for detecting the elemental content in silicon nitride requires a large amount of reagents, takes a long time, and has significant deviations in the detection results, making it difficult to accurately analyze the content of each element in silicon nitride. Summary of the Invention
[0006] The purpose of this invention is to provide a sample preparation method for silicon nitride analysis using ICP-OES. The sample preparation method of this invention can fully dissolve silicon nitride, thereby enabling the simultaneous testing of Si and impurity elements in silicon nitride ceramic materials.
[0007] To achieve this objective, the present invention adopts the following technical solution:
[0008] In a first aspect, the present invention provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method comprising the following steps:
[0009] (1) A mixture of silicon nitride and composite acid solution is obtained;
[0010] (2) After microwave digestion of the mixture, a sample preparation solution is obtained by volume adjustment.
[0011] The composite acid solution includes concentrated nitric acid, hydrofluoric acid, and concentrated sulfuric acid.
[0012] This invention utilizes a composite acid solution of concentrated nitric acid, hydrofluoric acid, and concentrated sulfuric acid to mix with silicon nitride and then microwave digests it. This process completely dissolves the silicon nitride, enabling the simultaneous testing of Si and impurity elements in silicon nitride ceramic materials. The method is rapid, safe, efficient, requires minimal reagents, and ensures complete dissolution, meeting the testing standards for ICP-OES.
[0013] Preferably, the silicon nitride in step (1) is in powder form.
[0014] Preferably, the silicon nitride is washed and dried before mixing in step (1).
[0015] Preferably, the washing includes acid washing and ethanol washing.
[0016] Preferably, the detergent used for pickling includes dilute hydrochloric acid and / or dilute nitric acid.
[0017] Preferably, the mass concentration of the dilute hydrochloric acid is 10% to 20%, for example: 10%, 12%, 15%, 18% or 20%, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0018] Preferably, the mass concentration of the dilute nitric acid is 20% to 30%, for example: 20%, 22%, 25%, 28% or 30%, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0019] Preferably, the ethanol washing time is 5 min to 15 min, for example: 5 min, 8 min, 10 min, 12 min or 15 min, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0020] Preferably, the volume ratio of concentrated nitric acid, hydrofluoric acid and concentrated sulfuric acid in the composite acid solution in step (1) is 1:(0.5~1.5):(0.5~1.5), for example: 1:0.5:1, 1:0.8:1.2, 1:1:1, 1:1.5:0.5 or 1:1.5:1.5, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0021] Preferably, the mass concentration of the concentrated nitric acid is 65% to 68%, for example: 65%, 65.5%, 66%, 67% or 68%, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0022] Preferably, the mass concentration of the hydrofluoric acid is 40% to 50%, for example: 40%, 42%, 45%, 48% or 50%, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0023] Preferably, the mass concentration of the concentrated sulfuric acid is 90% to 98%, for example: 90%, 92%, 95%, 96% or 98%, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0024] Preferably, the mass-volume ratio of silicon nitride to composite acid solution in step (1) is 10 g / L to 15 g / L, for example: 10 g / L, 11 g / L, 12 g / L, 14 g / L or 15 g / L, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0025] Preferably, the temperature of the microwave digestion process in step (2) is 220℃~230℃, for example: 220℃, 222℃, 225℃, 228℃ or 230℃, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0026] Preferably, the power of the microwave digestion process in step (2) is 300W to 500W, for example: 300W, 350W, 400W, 450W or 500W, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0027] Preferably, the microwave digestion process in step (2) takes 30 min to 90 min, for example, 30 min, 50 min, 60 min, 80 min or 90 min, etc., and is not limited to the listed values. Other unlisted values within this range are also applicable.
[0028] As a preferred embodiment of the present invention, the sample preparation method includes the following steps:
[0029] (1) After washing silicon nitride with acid and ethanol, it is mixed with a composite acid solution at a mass-volume ratio of 10 g / L to 15 g / L to obtain a mixture. The composite acid solution includes concentrated nitric acid, hydrofluoric acid and concentrated sulfuric acid in a volume ratio of 1:(0.5 to 1.5):(0.5 to 1.5).
[0030] (2) The mixture is microwave digested at a temperature of 220℃~230℃ and a power of 300W~500W for 30min~90min to obtain a clear solution. The clear solution is then diluted to a fixed volume to obtain a sample preparation solution.
[0031] Compared with the prior art, the present invention has the following beneficial effects:
[0032] (1) The sample preparation method described in this invention can fully dissolve silicon nitride, thereby enabling simultaneous testing of Si and impurity elements in silicon nitride ceramic materials.
[0033] (2) The sample preparation method described in this invention has a stable dissolution process, does not cause solution splashing, has a low component loss rate, and can improve the accuracy of the detection results.
[0034] (3) The silicon measurement deviation of the sample obtained by the silicon nitride sample preparation method for ICP-OES analysis described in this invention can be within 23.56%. By controlling the conditions and feed amount in the sample preparation process, the silicon measurement deviation of the sample can be within 1.2%, and the material deviation of impurities can be within 6.67%, or even 0. Detailed Implementation
[0035] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.
[0036] Example 1
[0037] This embodiment provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method including the following steps:
[0038] (1) After washing silicon nitride with dilute hydrochloric acid, wash it with ethanol for 10 min and dry it to obtain pretreated silicon nitride. Mix 3 mL of 68% concentrated nitric acid, 3 mL of 45% hydrofluoric acid and 3 mL of 98% concentrated sulfuric acid to obtain a composite acid solution. Take 0.1 g of pretreated silicon nitride and mix it with the composite acid solution to obtain a mixture.
[0039] (2) The mixture is microwave digested at 225°C and 400W for 60 minutes to obtain a clear solution. The clear solution is then diluted to a final volume to obtain a sample preparation solution.
[0040] Example 2
[0041] This embodiment provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method including the following steps:
[0042] (1) After washing silicon nitride with dilute nitric acid, wash it with ethanol for 10 min and dry it to obtain pretreated silicon nitride. Mix 4 mL of 65% concentrated nitric acid, 2 mL of 50% hydrofluoric acid and 4 mL of 90% concentrated sulfuric acid to obtain a composite acid solution. Take 0.1 g of pretreated silicon nitride and mix it with the composite acid solution to obtain a mixture.
[0043] (2) The mixture is microwave digested at 220°C and 300W for 90 minutes to obtain a clear solution. The clear solution is then diluted to a final volume to obtain a sample preparation solution.
[0044] Example 3
[0045] This embodiment provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method including the following steps:
[0046] (1) After washing silicon nitride with dilute nitric acid, wash it with ethanol for 10 min and dry it to obtain pretreated silicon nitride. Mix 3 mL of 66% concentrated nitric acid, 4.5 mL of 40% hydrofluoric acid and 2.5 mL of 98% concentrated sulfuric acid to obtain a composite acid solution. Take 0.1 g of pretreated silicon nitride and mix it with the composite acid solution to obtain a mixture.
[0047] (2) The mixture is microwave digested at 230°C and 500W for 30 minutes to obtain a clear solution. The clear solution is then diluted to a final volume to obtain a sample preparation solution.
[0048] Example 4
[0049] This embodiment provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method including the following steps:
[0050] (1) After washing silicon nitride with dilute hydrochloric acid, wash it with ethanol for 10 min and dry it to obtain pretreated silicon nitride. Mix 5 mL of 68% concentrated nitric acid, 2 mL of 45% hydrofluoric acid and 2 mL of 98% concentrated sulfuric acid to obtain a composite acid solution. Take 0.1 g of pretreated silicon nitride and mix it with the composite acid solution to obtain a mixture.
[0051] (2) The mixture is microwave digested at 225°C and 400W for 60 minutes to obtain a clear solution. The clear solution is then diluted to a final volume to obtain a sample preparation solution.
[0052] Example 5
[0053] This embodiment provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method including the following steps:
[0054] (1) After washing silicon nitride with dilute hydrochloric acid, wash it with ethanol for 10 min and dry it to obtain pretreated silicon nitride. Mix 2 mL of 68% concentrated nitric acid, 3.5 mL of 45% hydrofluoric acid and 3.5 mL of 98% concentrated sulfuric acid to obtain a composite acid solution. Take 0.1 g of pretreated silicon nitride and mix it with the composite acid solution to obtain a mixture.
[0055] (2) The mixture is microwave digested at 225°C and 400W for 60 minutes to obtain a clear solution. The clear solution is then diluted to a final volume to obtain a sample preparation solution.
[0056] Example 6
[0057] This embodiment provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method including the following steps:
[0058] (1) After washing silicon nitride with dilute hydrochloric acid, wash it with ethanol for 10 min and dry it to obtain pretreated silicon nitride. Mix 2 mL of 68% concentrated nitric acid, 2 mL of 45% hydrofluoric acid and 2 mL of 98% concentrated sulfuric acid to obtain a composite acid solution. Take 0.1 g of pretreated silicon nitride and mix it with the composite acid solution to obtain a mixture.
[0059] (2) The mixture is microwave digested at 225°C and 400W for 60 minutes to obtain a clear solution. The clear solution is then diluted to a final volume to obtain a sample preparation solution.
[0060] Example 7
[0061] This embodiment provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method including the following steps:
[0062] (1) After washing silicon nitride with dilute hydrochloric acid, wash it with ethanol for 10 min and dry it to obtain pretreated silicon nitride. Mix 4 mL of 68% concentrated nitric acid, 4 mL of 45% hydrofluoric acid and 4 mL of 98% concentrated sulfuric acid to obtain a composite acid solution. Take 0.1 g of pretreated silicon nitride and mix it with the composite acid solution to obtain a mixture.
[0063] (2) The mixture is microwave digested at 225°C and 400W for 60 minutes to obtain a clear solution. The clear solution is then diluted to a final volume to obtain a sample preparation solution.
[0064] Example 8
[0065] This embodiment provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method including the following steps:
[0066] (1) After washing silicon nitride with dilute hydrochloric acid, wash it with ethanol for 10 min and dry it to obtain pretreated silicon nitride. Mix 3 mL of 68% concentrated nitric acid, 3 mL of 45% hydrofluoric acid and 3 mL of 98% concentrated sulfuric acid to obtain a composite acid solution. Take 0.1 g of pretreated silicon nitride and mix it with the composite acid solution to obtain a mixture.
[0067] (2) The mixture is microwave digested at 200°C and 400W for 60 minutes to obtain a clear solution. The clear solution is then diluted to a final volume to obtain a sample preparation solution.
[0068] Comparative Example 1
[0069] This comparative example provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method comprising the following steps:
[0070] (1) Silicon nitride was washed with dilute hydrochloric acid and then washed with ethanol for 10 min and dried to obtain pretreated silicon nitride. 4.5 mL of 68% concentrated nitric acid and 4.5 mL of 45% hydrofluoric acid were mixed to obtain a composite acid solution. 0.1 g of pretreated silicon nitride was mixed with the composite acid solution to obtain a mixture.
[0071] (2) The mixture was microwave digested at 225°C and 400W, but the solution boiled and could not be sampled.
[0072] Comparative Example 2
[0073] This comparative example provides a sample preparation method for silicon nitride used in ICP-OES analysis, the sample preparation method comprising the following steps:
[0074] (1) After washing silicon nitride with dilute hydrochloric acid, wash it with ethanol for 10 min and then dry it to obtain pretreated silicon nitride. Mix 3 mL of 68% concentrated nitric acid, 3 mL of 45% hydrofluoric acid and 3 mL of 98% concentrated sulfuric acid to obtain a composite acid solution. Take 0.1 g of pretreated silicon nitride and mix it with the composite acid solution to obtain a mixture.
[0075] (2) Stir the mixture at 225°C for 60 minutes, filter to obtain a clear solution, and adjust the volume of the clear solution to obtain a sample preparation solution.
[0076] Performance testing:
[0077] The sample solutions obtained in the above examples and comparative examples were analyzed by ICP-OES, and the impurities measured included iron and aluminum. The test results are shown in Table 1. The deviation was calculated as follows: Deviation = |Actual value - Measured value| / Actual value × 100%.
[0078] Table 1
[0079]
[0080]
[0081] As can be seen from Table 1, and from Examples 1-3, the silicon measurement deviation of the sample obtained by the silicon nitride sample preparation method for ICP-OES analysis described in this invention can be within 23.56%. By controlling the conditions and feed amount in the sample preparation process, the silicon measurement deviation of the sample can be within 1.2%, and the material deviation of impurities can be within 6.67%, or even reach 0.
[0082] A comparison of Examples 1 and 4-5 shows that, in the sample preparation process of silicon nitride for ICP-OES analysis described in this invention, the volume ratio of concentrated nitric acid, hydrofluoric acid, and concentrated sulfuric acid in the composite acid solution affects the sample preparation effect. Controlling the volume ratio of concentrated nitric acid, hydrofluoric acid, and concentrated sulfuric acid in the composite acid solution to 1:(0.5~1.5):(0.5~1.5) yields better sample preparation results. If this range is exceeded, the dissolution effect will significantly decrease. Furthermore, if the proportion of concentrated sulfuric acid is too small, the temperature will be insufficient, resulting in incomplete sample dissolution.
[0083] A comparison of Examples 1 and 6-7 shows that, in the sample preparation process of silicon nitride for ICP-OES analysis, the mass-to-volume ratio of silicon nitride to the composite acid solution affects the sample preparation effect. Controlling the mass-to-volume ratio of silicon nitride to the composite acid solution at 10-15 g / L results in better sample preparation. If the amount of silicon nitride added is too high, the sample will not dissolve completely; if the amount of silicon nitride added is too low, it will lead to large data deviation and poor repeatability.
[0084] A comparison of Examples 1 and 8 shows that, in the sample preparation process of silicon nitride for ICP-OES analysis described in this invention, the microwave digestion temperature affects the sample preparation effect. Controlling the microwave digestion temperature at 220℃~230℃ yields better sample preparation results. If the microwave digestion temperature is too low, the sample will not dissolve completely; if it is too high, boiling may occur, making sample preparation impossible.
[0085] As can be seen from the comparison between Example 1 and Comparative Example 1, the addition of concentrated sulfuric acid to the composite acid solution in this invention can increase the microwave digestion temperature, thereby allowing silicon nitride to completely dissolve. If concentrated sulfuric acid is not added, the microwave temperature cannot reach the dissolution state. If the microwave digestion temperature is too low, the silicon nitride cannot be completely dissolved, resulting in significant deviations in the test results.
[0086] As can be seen from the comparison between Example 1 and Comparative Example 2, the conventional method uses open heating to dissolve silicon, which leads to a large amount of silicon volatilization. The microwave digestion method used in this invention is a sealed digestion method, which can retain silicon in silicon nitride to the greatest extent.
[0087] The applicant declares that 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 conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.
Claims
1. A sample preparation method for ICP-OES analysis of silicon nitride, characterized by, The sample preparation method includes the following steps: (1) A mixture is obtained by mixing silicon nitride with a composite acid solution; the composite acid solution includes concentrated nitric acid, hydrofluoric acid and concentrated sulfuric acid, the volume ratio of concentrated nitric acid, hydrofluoric acid and concentrated sulfuric acid in the composite acid solution is 1:(0.5~1.5):(0.5~1.5), the mass concentration of concentrated nitric acid is 65%~68%, the mass concentration of hydrofluoric acid is 40%~50%, and the mass concentration of concentrated sulfuric acid is 90%~98%; the mass-volume ratio of silicon nitride to composite acid solution is 10g / L~15g / L; (2) After the mixture is subjected to microwave digestion, the sample solution is obtained by volume adjustment. The temperature of the microwave digestion is 220℃~230℃.
2. The sample preparation method of claim 1, wherein The silicon nitride in step (1) is in powder form.
3. The sample preparation method as described in claim 1, characterized in that, Step (1) involves washing and drying the silicon nitride before mixing.
4. The sample preparation method as described in claim 3, characterized in that, The washing process includes acid washing and ethanol washing.
5. The sample preparation method as described in claim 4, characterized in that, The detergents used for pickling include dilute hydrochloric acid and / or dilute nitric acid.
6. The sample preparation method as described in claim 5, characterized in that, The mass concentration of the dilute hydrochloric acid is 10%~20%.
7. The sample preparation method as described in claim 5, characterized in that, The mass concentration of the dilute nitric acid is 20%~30%.
8. The sample preparation method as described in claim 4, characterized in that, The ethanol washing time is 5 min to 15 min.
9. The sample preparation method as described in claim 1, characterized in that, The power of the microwave digestion process in step (2) is 300W~500W.
10. The sample preparation method as described in claim 1, characterized in that, The microwave digestion process in step (2) takes 30 to 90 minutes.
11. The sample preparation method as described in claim 1, characterized in that, The sample preparation method includes the following steps: (1) After washing silicon nitride with acid and ethanol, it is mixed with a composite acid solution at a mass-volume ratio of 10 g / L to 15 g / L to obtain a mixture. The composite acid solution includes concentrated nitric acid, hydrofluoric acid and concentrated sulfuric acid in a volume ratio of 1:(0.5~1.5):(0.5~1.5). (2) The mixture is microwave digested at a temperature of 220℃~230℃ and a power of 300W~500W for 30min~90min to obtain a clear solution. The clear solution is then diluted to a final volume to obtain a sample preparation solution.