XRF (X-Ray Fluorescence) sample preparation and test method applied to inorganic non-metallic material

Abstract

The invention relates to the technical field of inorganic non-metallic material detection, in particular to an XRF sample preparation and test method applied to inorganic non-metallic materials, which comprises the following specific steps: drying an inorganic non-metallic material sample; grinding the sample by using a grinding machine, and screening by using a screen; determining the moisture content of the sample by adopting a moisture analyzer; adding magnesium oxide and boric acid into deionized water to obtain a magnesium borate compound; pouring the powder sample into the middle of a hopper, adding a magnesium borate compound at the periphery of the hopper to cover the powder, adding polytetrafluoroethylene, and pressing by using a tablet press to form a sheet sample; the magnesium oxide can react with boric acid to generate a stable compound, and the compound is more stable than single boric acid and is not easy to react with other components, so that the matrix effect caused by sample matrix difference can be reduced, the XRF analysis result is more accurate, and errors are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic non-metallic material detection, and specifically to an XRF sample preparation and testing method applied to inorganic non-metallic materials. Background Technique

[0002] Inorganic non-metallic materials, such as zirconia, have been widely used in the fields of ceramics, electronics, medicine, aerospace, etc. due to their excellent physical and chemical properties. However, the properties of these materials are often affected by their composition and microstructure. Therefore, accurate composition analysis of inorganic non-metallic materials is crucial. X-ray fluorescence spectroscopy (XRF) has been widely used in material composition analysis due to its non-destructive, fast response, and multi-element analysis capabilities. Currently, the testing of XRF mainly relies on testers to manually press sample tablets. Due to different pressing operation methods, the test results will vary. In view of this, we propose an XRF sample preparation and testing method applied to inorganic non-metallic materials. Summary of the Invention

[0003] The purpose of the present invention is to solve the above problems, standardize the operation steps, and reduce the test error, especially the error caused by the sample preparation step. This method realizes high-precision and rapid detection of the elemental composition in inorganic non-metallic solid powders through steps such as drying, grinding, screening, measuring the moisture content, and using the boric acid bottom pressing method for sample preparation.

[0004] To achieve the above purpose, the present invention provides an XRF sample preparation method applied to inorganic non-metallic materials, including the following steps:

[0005] S1.1. Place the inorganic non-metallic material sample in a drying oven for drying to remove the free water and bound water in the sample;

[0006] S1.2. Grind the dried sample with a grinder at a grinding speed of 200 - 600 rpm for a grinding time of 0.5 - 1 h, and then screen it through a sieve with a mesh size of 200 - 300 meshes;

[0007] S1.3. Use a moisture analyzer to measure the moisture content of the ground and screened sample, record the moisture content data of each sample, and control the moisture content below 20% to obtain a powder sample;

[0008] S1.4. Pour 2 g of the dried powder sample into the middle of the hopper, and use the pressing rod to flatten it so that the powder evenly covers the gasket. Add 2.5 g of magnesium borate complex to cover the powder evenly in three areas around the hopper and at the center of the hopper; at the same time, add polytetrafluoroethylene, and use a vibrating platform with a vibration frequency of 20 - 80 Hz and a vibration time of 15 - 30 min to ensure uniform mixing; use a tablet press to press the sample with a pressing pressure of 30 MPa and a holding pressure time of 1 min to form a thin film sample with a thickness of 2 - 5 mm.

[0009] Magnesium oxide can react with boric acid to form a stable complex, such as magnesium borate (MgBO2). This complex is more stable than boric acid alone and is not easily reactive with other components, which can reduce the matrix effect caused by sample matrix differences and make the XRF analysis results more accurate; by forming a stable complex, the interference caused by free boric acid can be reduced. Free boric acid may introduce unnecessary background signals in XRF analysis and affect the detection accuracy of target elements. A uniform sample can provide a more consistent fluorescence signal, thereby improving the signal-to-noise ratio of XRF analysis and making the detection results more reliable.

[0010] The generated complex usually has high hardness and density, which helps to form a denser sample during the tablet pressing process, reduce the porosity of the sample, improve the physical stability of the sample, and is more likely to form a flat surface after tablet pressing, reducing the XRF signal fluctuations caused by surface unevenness.

[0011] Polytetrafluoroethylene can significantly improve the mechanical strength of the sample, making it not easy to break or crack during the tablet pressing process. It also helps to form a stronger and flatter sample surface, reducing the risk of sample damage during sample preparation and testing; polytetrafluoroethylene helps to form a smooth and flat sample surface, ensuring the consistency of the incident angle and reflection path of X-rays and improving the accuracy of detection results; and polytetrafluoroethylene has very stable chemical properties and will not react with other components in the sample, reducing the possibility of chemical interference and ensuring the reliability of detection results.

[0012] Preferably, in S1.1, the drying temperature of the drying oven is 100 - 110 °C and the drying time is 1 - 2 h.

[0013] Preferably, in S1.2, the particle size of the ground sample is less than 200 mesh.

[0014] Preferably, in S1.3, the heating temperature of the moisture analyzer is 100 - 150 °C and the heating time is 10 - 30 min.

[0015] Preferably, in S1.4, the magnesium borate complex is prepared from magnesium oxide and boric acid together.

[0016] Preferably, magnesium oxide and boric acid are stirred by a magnetic stirrer to form a uniform suspension; at room temperature, the pH value of the suspension is adjusted to 7-10 with sodium hydroxide with a concentration of 0.05-0.1M, and continuously stirred at a speed of 100-200 rpm for 0.5-1 h; then vacuum dried to remove excess moisture to obtain a magnesium borate complex.

[0017] Preferably, the stirring speed of the magnetic stirrer is 200-300 rpm, and the stirring time is 0.5-1 h.

[0018] Preferably, the vacuum drying temperature is 60-80 °C, and the drying time is 2-3 h.

[0019] On the other hand, the present invention provides an XRF test method for inorganic non-metallic materials, which is used for the thin film samples described in any one of the above, and includes the following steps:

[0020] S2.1. Use an X-ray fluorescence spectrometer to detect the thin film sample, excite the elements in the sample with X-rays to generate characteristic fluorescence, collect the fluorescence signal with a detector, and analyze to obtain the content of the elements.

[0021] Preferably, in the S2.1, the voltage of the X-ray fluorescence spectrometer is 30-50 kV, the current is 20-40 mA, and the measurement time is 100-200 s.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. In the XRF sample preparation and test method for inorganic non-metallic materials, adding magnesium oxide can react with boric acid to form a stable complex. This complex is more stable than boric acid alone and is not easy to react with other components, which can reduce the matrix effect caused by sample matrix differences, making the XRF analysis results more accurate; it can reduce the interference brought by free boric acid and affect the detection accuracy of target elements. A uniform sample can provide a more consistent fluorescence signal, thereby improving the signal-to-noise ratio of XRF analysis and making the detection results more reliable.

[0024] 2. In the XRF sample preparation and test method for inorganic non-metallic materials, adding polytetrafluoroethylene can significantly improve the mechanical strength of the sample, making it not easy to break or crack during the tablet pressing process, and also helps to form a more solid and flat sample surface, reducing the risk of sample damage during preparation and testing; and polytetrafluoroethylene has very stable chemical properties and will not react with other components in the sample, reducing the possibility of chemical interference and ensuring the reliability of the detection results. Specific embodiments

[0025] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] In the present invention, the inorganic non-metallic material is preferably zirconia.

[0027] Embodiment 1: An XRF sample preparation and testing method for inorganic non-metallic materials, comprising the following steps:

[0028] S2.1. Detect the thin film sample using an X-ray fluorescence spectrometer. The voltage of the X-ray fluorescence spectrometer is 40 kV, the current is 30 mA, and the measurement time is 100 s. The elements in the sample are excited by X-rays to generate characteristic fluorescence. The fluorescence signal is collected by a detector and the element content is analyzed by a data processing system.

[0029] Among them, the XRF sample preparation steps for zirconia are as follows:

[0030] S1.1. Place the zirconia material in an oven for drying. The drying temperature is 110 °C and the drying time is 2 h to remove free water and bound water in the zirconia.

[0031] S1.2. Grind the dried zirconia using a grinder. The grinding speed is 300 rpm and the grinding time is 1 h to make its particle size less than 200 mesh. The ground zirconia is screened using a 200-mesh sieve.

[0032] S1.3. Use a moisture analyzer to measure the moisture content of the ground and screened zirconia. The heating temperature of the moisture analyzer is 120 °C and the heating time is 30 min. Record the moisture content data of each sample and control the moisture content below 20%.

[0033] S1.4. Add magnesium oxide and boric acid to deionized water and stir well using a magnetic stirrer. The stirring speed is 300 rpm and the stirring time is 0.5 h until a uniform suspension is formed. Adjust the pH value of the suspension to 8 with 0.05 M sodium hydroxide at room temperature and continue to stir at a speed of 200 rpm for 0.5 h. Then carry out vacuum drying. The drying temperature is 60 °C and the drying time is 2 h to remove excess moisture and obtain a magnesium borate complex.

[0034] S1.5. Pour 2 g of the dried zirconia sample into the middle of the hopper, and use a pressing rod to flatten it so that the powder evenly covers the gasket. Add 2.5 g of the magnesium borate complex evenly to cover the powder in three areas around the hopper and at the center of the hopper. At the same time, add polytetrafluoroethylene, and use a vibration platform with a vibration frequency of 40 Hz and a vibration time of 30 min to ensure uniform mixing. Use a tablet press to press the sample with a pressing pressure of 30 MPa and a pressure holding time of 1 min to form a thin sheet sample with a thickness of 3 mm.

[0035] Example 2: An XRF sample preparation and testing method for inorganic non-metallic materials, comprising the following steps:

[0036] S2.1. Use an X-ray fluorescence spectrometer to detect the thin sheet sample. The voltage of the X-ray fluorescence spectrometer is 40 kV, the current is 30 mA, and the measurement time is 100 s. Excite the elements in the sample with X-rays to generate characteristic fluorescence, collect the fluorescence signal using a detector, and analyze the element content through a data processing system.

[0037] Among them, the XRF sample preparation steps for zirconia are as follows:

[0038] S1.1. Place the zirconia material in an oven for drying at a drying temperature of 110 °C and a drying time of 2 h to remove free water and bound water in the zirconia.

[0039] S1.2. Grind the dried zirconia using a grinder at a grinding speed of 300 rpm for 1 h to make its particle size less than 200 mesh. Screen the ground zirconia through a 200-mesh sieve.

[0040] S1.3. Use a moisture analyzer to measure the moisture content of the ground and sieved zirconia. The heating temperature of the moisture analyzer is 120 °C and the heating time is 30 min. Record the moisture content data of each sample and control the moisture content below 20%.

[0041] S1.4. Add magnesium oxide and boric acid to deionized water, and use a magnetic stirrer to stir well at a stirring speed of 300 rpm for 0.5 h until a uniform suspension is formed. Adjust the pH value of the suspension to 8 with 0.05 M sodium hydroxide at room temperature and continue stirring at a speed of 200 rpm for 0.5 h. Then carry out vacuum drying at a drying temperature of 60 °C and a drying time of 2 h to remove excess moisture to obtain the magnesium borate complex.

[0042] S1.5. Pour 2g of dried zirconium oxide sample into the middle of the hopper, flatten it with a pressure rod so that the powder is evenly spread on the gasket, and evenly add 2.5g of magnesium borate compound to the three areas outside the hopper and the center of the hopper to cover the powder; at the same time, add polytetrafluoroethylene and use a vibration platform with a vibration frequency of 40Hz and a vibration time of 30min to ensure uniform mixing; use a tablet press to press the sample with a pressure of 30MPa and a pressure holding time of 1min to form a thin sheet sample with a thickness of 5mm.

[0043] Example 3: An XRF sample preparation and testing method for inorganic non-metallic materials, comprising the following steps:

[0044] S2.1. Use an X-ray fluorescence spectrometer to detect the thin-section sample. The voltage of the X-ray fluorescence spectrometer is 40kV, the current is 30mA, and the measurement time is 100s. X-rays are used to excite the elements in the sample to produce characteristic fluorescence. The fluorescence signal is collected by a detector, and the element content is obtained through analysis by a data processing system.

[0045] Among them, the XRF sample preparation steps of zirconium oxide are as follows:

[0046] S1.1. Place the zirconium oxide material in a drying oven for drying at a temperature of 110°C for 2 hours to remove free water and bound water in the zirconium oxide;

[0047] S1.2, grind the dried zirconium oxide with a grinder at a grinding speed of 300 rpm for 1 h, so that the particle size is less than 200 mesh; sieve the ground zirconium oxide with a 200-mesh sieve;

[0048] S1.3. Use a moisture analyzer to measure the moisture content of the ground and sieved zirconium oxide. The heating temperature of the moisture analyzer is 120°C and the heating time is 30 minutes. Record the moisture content data of each sample and control the moisture content below 20%;

[0049] S1.4, adding magnesium oxide and boric acid to deionized water, stirring with a magnetic stirrer at a speed of 300 rpm for 0.5 h, until a uniform suspension is formed; adjusting the pH value of the suspension to 8 with 0.05 M sodium hydroxide at room temperature, stirring at a speed of 200 rpm for 0.5 h; then vacuum drying at a drying temperature of 60 ° C for 2 h to remove excess water to obtain a magnesium borate complex;

[0050] S1.5. Pour 2g of dried zirconium oxide sample into the middle of the hopper, flatten it with a pressure rod so that the powder is evenly spread on the gasket, and evenly add 2.5g of magnesium borate compound to the three areas outside the hopper and the center of the hopper to cover the powder; at the same time, add polytetrafluoroethylene and use a vibration platform with a vibration frequency of 40Hz and a vibration time of 30min to ensure uniform mixing; use a tablet press to press the sample with a pressure of 30MPa and a pressure holding time of 1min to form a thin sheet sample with a thickness of 2mm.

[0051] Example 4: An XRF sample preparation and testing method applied to inorganic non-metallic materials, comprising the following steps;

[0052] S2.1. Use an X-ray fluorescence spectrometer to detect the thin-section sample. The voltage of the X-ray fluorescence spectrometer is 40kV, the current is 30mA, and the measurement time is 100s. X-rays are used to excite the elements in the sample to produce characteristic fluorescence. The fluorescence signal is collected by a detector, and the element content is obtained through analysis by a data processing system.

[0053] Among them, the XRF sample preparation steps of zirconium oxide are as follows:

[0054] S1.1. Place the zirconium oxide material in a drying oven for drying at a temperature of 110°C for 2 hours to remove free water and bound water in the zirconium oxide;

[0055] S1.2, grind the dried zirconium oxide with a grinder at a grinding speed of 300 rpm for 1 h, so that the particle size is less than 200 mesh; sieve the ground zirconium oxide with a 200-mesh sieve;

[0056] S1.3. Use a moisture analyzer to measure the moisture content of the ground and sieved zirconium oxide. The heating temperature of the moisture analyzer is 120°C and the heating time is 30 minutes. Record the moisture content data of each sample and control the moisture content below 20%;

[0057] S1.4, adding magnesium oxide and boric acid to deionized water, stirring with a magnetic stirrer at a speed of 300 rpm for 0.5 h, until a uniform suspension is formed; adjusting the pH value of the suspension to 7 with 0.05 M sodium hydroxide at room temperature, stirring at a speed of 200 rpm for 0.5 h; then vacuum drying at a drying temperature of 60 ° C for 2 h to remove excess water to obtain a magnesium borate complex;

[0058] S1.5. Pour 2 g of the dried zirconia sample into the middle of the hopper, and use the pressing rod to flatten it so that the powder evenly covers the gasket. Add 2.5 g of magnesium borate complex evenly to cover the powder in three areas around the hopper and at the center of the hopper. At the same time, add polytetrafluoroethylene, and use a vibration platform with a vibration frequency of 40 Hz and a vibration time of 30 min to ensure uniform mixing. Use a tablet press to press the sample with a pressing pressure of 30 MPa and a holding pressure time of 1 min to form a thin film sample with a thickness of 2 mm.

[0059] Comparative Example 1

[0060] Adopt the method of Example 3 to remove magnesium oxide.

[0061] Comparative Example 2

[0062] Adopt the method of Example 3 to remove polytetrafluoroethylene.

[0063] Comparative Example 3

[0064] Adopt the method of Example 3 and use the traditional tablet pressing method.

[0065] Through steps such as drying, grinding, screening, measuring moisture content, using boric acid as a bottom layer, and adding magnesium oxide and polytetrafluoroethylene for tablet pressing to prepare samples, the present invention realizes high-precision and rapid detection of elemental components in inorganic non-metallic solid powders, reduces test errors. The specific test effects are as follows:

[0066] Parallel testing: Conduct multiple parallel tests on the same sample, record the results of each test, and calculate the average value and standard deviation of the multiple test results. The smaller the standard deviation, the more stable the test results; the larger the standard deviation, the greater the random error.

[0067] Table 1 Test data of inorganic non-metallic materials in Examples 1 - 4 and Comparative Examples 1 - 3

[0068] Examples / Comparative Examples Average wt. % Standard Deviation wt. % Example 1 67.0 0.2 Example 2 67.2 0.1 Example 3 67.1 0.1 Example 4 67.1 0.1 Comparative Example 1 66.2 0.4 Comparative Example 2 66.4 0.4 Comparative Example 3 65.9 0.5

[0069] It can be seen from Examples 1 - 4 that the elemental content in the inorganic non-metallic material shows a relatively high average value and a relatively low standard deviation.

[0070] It can be seen from Example 3 and Comparative Example 1 that when magnesium oxide is removed, the average value of the elemental content in the inorganic non-metallic material decreases significantly, and the standard deviation increases significantly;

[0071] The presence of magnesium oxide may shield or enhance the XRF signals of other elements, causing changes in matrix effects and resulting in altered detection sensitivities of certain elements; as an adhesive or stabilizer, magnesium oxide helps maintain the uniformity of the sample; magnesium oxide generally has good dispersibility and adhesiveness, which helps keep the sample particles evenly distributed; after removing magnesium oxide, the sample particles may agglomerate or be unevenly distributed, and the sample is more likely to break or develop cracks, affecting the accuracy of XRF analysis, leading to unstable detection results and an increase in standard deviation; the removal of magnesium oxide may cause a decrease in the sample density, resulting in changes in the X-ray penetration depth and path, affecting the detection results; although magnesium oxide itself does not introduce significant background signals, its presence can reduce the background interference of certain light elements. After removing magnesium oxide, the background signal may increase, leading to fluctuations in the detection results, a significant decrease in the average value, and a significant increase in the standard deviation.

[0072] Taking Example 3 as the optimal example and in combination with Comparative Example 2, it can be seen that when polytetrafluoroethylene is removed, the average value of the element content in the inorganic non-metallic material decreases significantly, and the standard deviation increases significantly;

[0073] Polytetrafluoroethylene has good dispersibility and adhesiveness, which can help keep the sample particles evenly distributed and also helps improve the density of the sample. After removing polytetrafluoroethylene, the sample may become loose, resulting in changes in the X-ray penetration depth and path, affecting the detection results; polytetrafluoroethylene helps form a smooth and flat sample surface. After removing polytetrafluoroethylene, the sample surface may become uneven, affecting the incident angle and reflection path of the X-ray, leading to unstable detection results and an increase in standard deviation.

[0074] Taking Example 3 as the optimal example and in combination with Comparative Example 3, it can be seen that using the traditional pressing method, the average value of the element content in the inorganic non-metallic material decreases significantly, and the standard deviation increases significantly;

[0075] The synergistic effect of the magnesium borate complex and polytetrafluoroethylene helps disperse the sample particles more evenly and reduce agglomeration; polytetrafluoroethylene provides additional mechanical strength, while the magnesium borate complex enhances the density of the sample. The two work together to adjust the matrix effect of the sample and reduce the background interference of certain elements. Using the traditional pressing method will cause changes in the matrix effect, resulting in changes in the fluorescence intensity of certain elements and affecting the detection results.

[0076] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and the descriptions in the specification are only preferred examples of the present invention, and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. An XRF sample preparation method applied to inorganic non-metallic materials, characterized in that It includes the following steps: S1.

1. Place the inorganic non-metallic material sample in an oven for drying to remove free water and bound water in the sample; S1.

2. Grind the dried sample with a grinder at a grinding speed of 200 - 600 rpm for a grinding time of 0.5 - 1 h, and then screen it through a sieve with a mesh size of 200 - 300 meshes; S1.

3. Use a moisture analyzer to measure the moisture content of the ground and screened sample, record the moisture content data of each sample, control the moisture content below 20%, and obtain a powder sample; S1.

4. Take 2 g of the dried powder sample and pour it into the middle of the hopper, use a pressing rod to flatten it so that the powder evenly covers the gasket, evenly add 2.5 g of magnesium borate complex to cover the powder in three areas around the hopper and the center of the hopper; at the same time, add polytetrafluoroethylene and use a vibration platform with a vibration frequency of 20 - 80 Hz and a vibration time of 15 - 30 min to ensure uniform mixing; use a tablet press to press the sample with a pressing pressure of 30 MPa and a holding pressure time of 1 min to form a thin sheet sample with a thickness of 2 - 5 mm.

2. The XRF sample preparation method applied to inorganic non-metallic materials according to claim 1, wherein, In S1.1, the drying temperature of the oven is 100 - 110 °C and the drying time is 1 - 2 h.

3. The XRF sample preparation method applied to inorganic non-metallic materials according to claim 1, characterized in that, In S1.2, the particle size of the ground sample is less than 200 meshes.

4. The XRF sample preparation method applied to inorganic non-metallic materials according to claim 1, characterized in that, In S1.3, the heating temperature of the moisture analyzer is 100 - 150 °C and the heating time is 10 - 30 min.

5. The XRF sample preparation method applied to inorganic non-metallic materials according to claim 1, characterized in that, In S1.4, the magnesium borate complex is prepared from magnesium oxide and boric acid together.

6. The XRF sample preparation method for inorganic non-metallic materials according to claim 5, wherein Magnesium oxide and boric acid are stirred by a magnetic stirrer to form a uniform suspension; at room temperature, the pH value of the suspension is adjusted to 7 - 10 with a sodium hydroxide solution with a concentration of 0.05 - 0.1 M, and continuously stirred at a speed of 100 - 200 rpm for 0.5 - 1 h; then vacuum dried to remove excess moisture to obtain the magnesium borate complex.

7. The XRF sample preparation method applied to inorganic non-metallic materials according to claim 6, characterized in that, The stirring speed of the magnetic stirrer is 200 - 300 rpm and the stirring time is 0.5 - 1 h.

8. The XRF sample preparation method applied to inorganic non-metallic materials according to claim 6, characterized in that, The vacuum drying temperature is 60 - 80 °C and the drying time is 2 - 3 h.

9. An XRF testing method for inorganic non-metallic materials, used to test the thin film samples described in any one of claims 1-8, characterized in that: The following is an XRF test method applied to inorganic non-metallic materials: S2.

1. Use an X-ray fluorescence spectrometer to detect the thin sheet sample, excite the elements in the sample with X-rays to generate characteristic fluorescence, collect the fluorescence signal with a detector, and analyze to obtain the element content.

10. The XRF test method for inorganic non-metallic materials according to claim 9, wherein In S2.1, the voltage of the X-ray fluorescence spectrometer is 30 - 50 kV, the current is 20 - 40 mA, and the measurement time is 100 - 200 s.