Electron microscopic analysis method for hydrogen distribution in nanoscale resolution metal material
By acquiring and processing electron energy loss spectra using transmission electron microscopy, the problem of nanoscale microscopic resolution of hydrogen distribution in metallic materials was solved, high spatial resolution hydrogen distribution images were obtained, and hydrogen diffusion pathways and hydrogen absorption mechanisms were revealed.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INSTITUTE OF NUCLEAR PHYSICS AND CHEMISTRY CHINA ACADEMY OF ENGINEERING PHYSICS
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-05
AI Technical Summary
Current technologies cannot achieve nanoscale micro-resolution analysis of hydrogen distribution in metallic materials, resulting in inaccurate analysis of hydrogen diffusion paths, hydrogen interface distribution characteristics, and hydrogen absorption mechanisms.
Transmission electron microscopy was used to acquire electron energy loss spectra. Data sets were obtained by pixel scanning, and zero-loss peak alignment, peak intensity normalization, plasma peak line extraction, and Gaussian smoothing were performed. Combined with grayscale imaging, hydrogen distribution images were obtained.
This study achieves nanoscale spatial resolution hydrogen distribution analysis in metallic materials, clearly showing the distribution characteristics of hydrogenated/unhydrogenated interfaces and grain boundaries, and providing important information on hydrogen diffusion pathways and hydrogen absorption mechanisms.
Smart Images
Figure CN121978135A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of transmission electron microscopy (TEM) microanalysis technology, and in particular to an electron microanalysis method for hydrogen distribution in metallic materials at nanoscale resolution. Background Technology
[0002] Metallic materials have significant applications in hydrogen storage and nuclear energy. They can absorb hydrogen to form metal hydrides for hydrogen storage, while in nuclear energy, metallic materials are susceptible to hydrogen embrittlement failure due to hydrogen permeation from the hydrogen environment. Analyzing the hydrogen distribution in metallic materials can provide crucial information on the hydrogen diffusion reaction mechanism and hydrogen distribution characteristics in hydrogen storage or nuclear energy metals. This has significant application prospects in the study of hydrogen absorption mechanisms in metallic materials and the design of hydrogen embrittlement-resistant materials.
[0003] Currently, analytical techniques for hydrogen distribution in metallic materials mainly include secondary ion mass spectrometry (SIMS), three-dimensional atom probe tomography (APT), and reflected electron energy loss spectroscopy (REELS). SIMS analyzes the sample point-by-point and layer-by-layer from the surface to the bulk phase by ion etching, with a spatial resolution typically at the hundred-nanometer level. APT, on the one hand, requires the sample to be made into a needle tip, which increases the sample preparation difficulty, and on the other hand, the tip processing accelerates the loss of hydrogen from the original hydrogen-containing metal sample, thus introducing analytical errors. REELS is mainly used for the study of surface chemistry and adsorption of solid samples, and its spatial resolution is only at the micrometer level.
[0004] Therefore, the aforementioned techniques for analyzing hydrogen distribution in metallic materials still suffer from insufficient spatial resolution and significant analytical errors introduced by tip sample preparation. Furthermore, the extremely small atomic number of hydrogen makes it difficult to achieve nanoscale microscopic resolution analysis of hydrogen distribution in metallic materials. This limits research on hydrogen diffusion paths, hydrogen interface distribution characteristics, hydrogen absorption uniformity, and hydrogen absorption mechanisms in metallic materials. Therefore, it is necessary to develop a nanoscale resolution electron microscopy method for analyzing hydrogen distribution in metallic materials to achieve nanoscale microscopic resolution analysis of hydrogen distribution in metallic materials. Summary of the Invention
[0005] The purpose of this application is to provide an electron microscopy method for analyzing hydrogen distribution in metallic materials at nanoscale resolution, aiming to solve the technical problem that the inability to accurately determine the hydrogen distribution in metallic materials leads to inaccurate analysis of hydrogen diffusion paths, hydrogen interface distribution characteristics, hydrogen absorption uniformity, or hydrogen absorption reaction mechanisms in metallic materials.
[0006] This application provides an electron microscopy method for analyzing hydrogen distribution in metallic materials at nanoscale resolution. The method includes: loading the sample to be tested onto a transmission electron microscope; the sample to be tested is a metallic material; selecting an electron energy loss spectral acquisition mode; and performing pixel-by-pixel scanning of the test area of the sample to obtain the original electron energy loss spectral dataset P. ijThe region to be measured is the region containing grain boundaries, phase boundaries, or void interfaces; i represents the row number of the pixel, j represents the column number of the pixel, and both i and j are positive integers greater than or equal to 1; for the electronic energy loss spectrum dataset P ij The zero-loss peaks of the electron energy loss spectrum corresponding to each pixel are zeroed out to obtain the centered electron energy loss spectrum dataset A. ij Using the plasma peak with a peak position range of 15 eV to 23 eV in the electron energy loss spectrum as the reference peak, the electron energy loss spectrum dataset A was analyzed. ij The intensity of each spectral line plasma peak was normalized to obtain the electron energy loss spectrum dataset N after peak intensity normalization. ij In the electron energy loss spectrum dataset N ij We selected plasma peak signal lines with peak positions ranging from 15 eV to 23 eV in the electron energy loss spectrum and extracted the plasma peak signal spectral line dataset E. ij ; For the plasma peak signal spectral line dataset E ij Gaussian smoothing was performed to obtain the Gaussian smoothed plasma peak signal spectral line dataset S. ij Read the plasma peak signal spectral line dataset S ij The peak position of the intermediate ion peak signal spectrum line was obtained and two-dimensional imaging was performed using grayscale imaging. The grayscale value of the image reflects the degree of hydrogen absorption, thus obtaining the microscopic information of hydrogen distribution in the transmission electron microscope image of the metallic material.
[0007] In an optional embodiment of this application, the optical path of the transmission electron microscope is set to a scanning transmission dark field imaging mode.
[0008] In an optional implementation of this application, the acquisition step size of the electron energy loss spectral acquisition mode is 1nm~50nm, and the acquisition time of the electron energy loss spectral acquisition mode for each pixel is 0.5s~2s.
[0009] In an optional embodiment of this application, before scanning and acquisition, the camera length, the aperture of the condenser lens aperture, and the aperture of the electron energy loss spectrum receiving aperture are set, the electron beam is moved into the rear lens barrel imaging filter, and the receiving aperture angle is set.
[0010] In an optional embodiment of this application, the camera length is 29.5mm to 58mm.
[0011] In an optional embodiment of this application, the aperture size of the condenser lens is 20μm~70μm.
[0012] In an optional embodiment of this application, the aperture of the electron energy loss spectrum receiving aperture is 2.5 mm.
[0013] In an optional embodiment of this application, the receiving aperture angle is 12.78 mrad to 25.12 mrad.
[0014] In an optional embodiment of this application, the thickness of the sample to be tested is 50nm~100nm.
[0015] In an optional embodiment of this application, the preparation method of the sample to be tested includes: firstly, preparing a transmission electron microscope sample with a thickness of 150nm~200nm using a focused ion beam microscope, and then reducing the thickness of the transmission electron microscope sample to 50nm~100nm using a microbeam fixed-point ion thinning system.
[0016] The beneficial effects of the electron microscopy method for analyzing hydrogen distribution in nanoscale resolution metallic materials provided in this application are as follows: The electron microscopy method for analyzing hydrogen distribution in metallic materials at nanoscale resolution provided in this application obtains high spatial resolution images of hydrogen distribution at the nanoscale by performing zero-loss peak alignment, peak intensity normalization, inductively coupled plasma (ICP) peak line extraction, ICP peak line smoothing, ICP peak position reading, and two-dimensional imaging on an electron energy loss spectrum set with nanoscale spatial resolution characteristics. The operation is simple and easy to perform, and the obtained hydrogen distribution images show clear regional boundaries, intuitively and clearly displaying the hydrogenation distribution characteristics inside the metallic material (such as the hydrogenation homogeneity of hydrogenation at hydrogenated / unhydrogenated interfaces and grain boundaries). This method overcomes the problems of insufficient spatial resolution and large analytical errors introduced by tip sample preparation in existing methods. It can provide important information on hydrogen diffusion paths, hydrogen interface distribution characteristics, hydrogen absorption homogeneity, and hydrogen absorption mechanisms in metallic materials, and has significant implications for understanding the diffusion reaction mechanism of hydrogen in metallic materials. Attached Figure Description
[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 A flowchart of the electron microscopy method for analyzing hydrogen distribution in nanoscale resolution metallic materials provided in this application.
[0019] Figure 2 This is a scanning transmission dark-field image of the grain boundary region of the titanium hydride electron microscope sample with complete hydrogen absorption in Example 1 of this application.
[0020] Figure 3 This is a microscopic image of the hydrogen distribution in the grain boundary region of the titanium hydride electron microscope sample that has completely absorbed hydrogen in Example 1 of this application.
[0021] Figure 4 This is a scanning transmission dark-field image of the hydrogenated / unhydrogenated interface region of the titanium hydrogenate electron microscope sample in Example 2 of this application, which did not absorb hydrogen sufficiently.
[0022] Figure 5 This is a microscopic image of the hydrogen distribution in the hydrogenated / unhydrogenated interface region of the hydrogenated titanium sample in Example 2 of this application, which did not absorb hydrogen sufficiently. Detailed Implementation
[0023] This application provides an electron microscopy method for analyzing hydrogen distribution in metallic materials at nanoscale resolution, including: The sample to be tested is loaded into the transmission electron microscope; the sample to be tested is a metallic material.
[0024] Select the electron energy loss spectral acquisition mode, and perform pixel-by-pixel scanning acquisition on the test area of the sample to obtain the raw electron energy loss spectral dataset P. ij The region to be tested is the region where the grain boundary, phase boundary, or hole interface is located; i represents the row number of the pixel and j represents the column number of the pixel, and both i and j are positive integers greater than or equal to 1.
[0025] For the electron energy loss spectrum dataset P ij The zero-loss peaks of the electron energy loss spectrum corresponding to each pixel are zeroed out to obtain the centered electron energy loss spectrum dataset A. ij .
[0026] Using the plasma peak with a peak position range of 15 eV to 23 eV in the electron energy loss spectrum as the reference peak, the electron energy loss spectrum dataset A was analyzed. ij The intensity of each spectral line plasma peak was normalized to obtain the electron energy loss spectrum dataset N after peak intensity normalization. ij .
[0027] In the electron energy loss spectrum dataset N ij We selected plasma peak signal lines with peak positions ranging from 15 eV to 23 eV in the electron energy loss spectrum and extracted the plasma peak signal spectral line dataset E. ij .
[0028] Data set E of plasma peak signal spectral lines ij Gaussian smoothing was performed to obtain the Gaussian smoothed plasma peak signal spectral line dataset S. ij .
[0029] Read the plasma peak signal spectral line dataset S ij The peak position of the intermediate ion peak signal spectrum line was obtained and two-dimensional imaging was performed using grayscale imaging. The grayscale value of the image reflects the degree of hydrogen absorption, thus obtaining the microscopic information of hydrogen distribution in the transmission electron microscope image of the metallic material.
[0030] The electron microscopy method for hydrogen distribution analysis in metallic materials with nanoscale resolution provided in this application is a method that can achieve hydrogen distribution analysis at nanoscale resolution. This method obtains a high spatial resolution image of hydrogen distribution in metallic materials at the nanoscale by performing zero-loss peak alignment, peak intensity normalization, inductively coupled plasma (ICP) peak line extraction, ICP peak line smoothing, ICP peak position reading, and two-dimensional imaging on an electron energy loss spectrum set with nanoscale spatial resolution characteristics. The operation steps are simple and easy to implement, and the obtained hydrogen distribution image has clear regional boundaries, which can intuitively and clearly show the hydrogenation distribution characteristics inside the metallic material (such as the hydrogenation uniformity of hydrogenated / unhydrogenated interfaces, grain boundaries, etc.).
[0031] This method overcomes the problems of insufficient spatial resolution and large analytical errors introduced by tip sample preparation in existing methods. It can provide important information on hydrogen diffusion paths, hydrogen interface distribution characteristics, hydrogen absorption uniformity and hydrogen absorption mechanism in metallic materials. It has important implications for understanding the diffusion reaction mechanism of hydrogen in metallic materials and has important application prospects in the fields of hydrogen absorption mechanism research in metallic materials and hydrogen embrittlement resistance material design.
[0032] Figure 1 For a flowchart of the electron microscopy method for analyzing hydrogen distribution in nanoscale resolution metallic materials provided in this application, please refer to [link / reference]. Figure 1 The electron microscopy method for analyzing hydrogen distribution in nanoscale resolution metallic materials specifically includes the following steps: S10, Preparation and loading of transmission electron microscopy samples.
[0033] S11, Preparation of transmission electron microscopy samples.
[0034] In this application, the sample to be tested is a metallic material.
[0035] In some optional embodiments of this application, the thickness of the sample to be tested is 50 nm to 100 nm.
[0036] As an example, the thickness of the sample to be tested can be any one of 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm and 100nm or a range between any two.
[0037] Furthermore, in some optional embodiments of this application, the preparation method of the sample to be tested includes: firstly, preparing a transmission electron microscope sample with a thickness of 150nm~200nm using a focused ion beam microscope, and then reducing the thickness of the transmission electron microscope sample to 50nm~100nm using a microbeam fixed-point ion thinning system.
[0038] Specifically, a microbeam-based point-to-point ion thinning system is used to clean and thin both sides of the transmission electron microscope (TEM) sample until the surface of the TEM sample is clean and reaches a thickness range of 50 nm to 100 nm.
[0039] Among them, a clean transmission electron microscope (TEM) sample surface includes: no gallium ion or carbon deposits on the TEM sample surface.
[0040] As an example, the focused ion beam microscope used was the Scios 2 HiVac focused ion beam microscope from Thermofisher Scientific, USA, with an accelerating voltage of 2kV~30kV.
[0041] As an example, the microbeam localized ion thinning system adopts the NanoMill 1040 microbeam localized ion thinning system from the United States, with an ion energy of 800eV~1200eV and an ion beam current of 100μA~200μA.
[0042] S12, Loading of transmission electron microscopy sample.
[0043] The transmission electron microscope (TEM) sample is mounted on the TEM sample holder and is ready for measurement.
[0044] As an example, the transmission electron microscope used is the Themis Z double spherical aberration corrected transmission electron microscope from Thermofisher Scientific, USA. The operating voltage is 80kV~300kV, the camera length is 29.5mm~185mm, the condenser aperture is 20μm~150μm, the electron energy loss spectroscopy receiving aperture is 2.5mm~5mm, and the receiving aperture angle is 4.005mrad~50.23mrad.
[0045] S20, Transmission Electron Microscope Optical Path Setup and Analysis Area Selection.
[0046] Set the transmission electron microscope (TEM) optical path to scanning transmission dark-field imaging mode. Move the TEM sample holder to center the thin-film TEM sample in the field of view, adjust to positive focus, and select the interface region as the region of interest. The region of interest is defined as a region in the dark-field image with clearly defined boundaries, such as grain boundaries, phase boundaries, or pore interfaces.
[0047] S30: Set the electron energy loss spectrum acquisition optical path and scanning parameters to obtain the electron energy loss spectrum dataset.
[0048] S31, set up the optical path for collecting electron energy loss spectrum.
[0049] Set the camera length, condenser aperture, and electron energy loss spectrum receiving aperture. Move the electron beam into the rear lens barrel imaging filter and set the receiving aperture angle according to the camera length and electron energy loss spectrum receiving aperture.
[0050] In some optional embodiments of this application, the camera length is 29.5mm to 58mm.
[0051] As an example, the camera length can be any one of 29.5mm, 37mm, 46mm, and 58mm.
[0052] In some optional embodiments of this application, the aperture size of the condenser lens is 20μm~70μm.
[0053] As an example, the aperture size of the condenser lens can be any one of 20μm, 50μm, and 70μm.
[0054] In some optional embodiments of this application, the aperture of the electron energy loss spectrum receiving aperture is 2.5 mm.
[0055] In some optional embodiments of this application, the receiving aperture angle is 12.78 mrad to 25.12 mrad.
[0056] As an example, the receiving aperture angle can be any one of 12.78 mrad, 16.11 mrad, 20.02 mrad, and 25.12 mrad.
[0057] S32, set the scan parameters.
[0058] In this application, the electron energy loss spectral acquisition mode is selected.
[0059] In some optional embodiments of this application, the acquisition step size of the electron energy loss spectral acquisition mode is 1nm~50nm, and the acquisition time of the electron energy loss spectral acquisition mode for the pixel is 0.5s~2s.
[0060] As an example, the acquisition step size can be any one of 1nm, 2nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm and 50nm or a range between any two; the acquisition time can be any one of 0.5s, 0.75s, 1s, 1.25s, 1.5s, 1.75s and 2s or a range between any two.
[0061] By setting the optical path and scanning parameters for electron energy loss spectroscopy acquisition as described above, nanometer-scale spatially resolved electron energy loss spectroscopy acquisition can be achieved, and the quality of spectral data can be improved.
[0062] S33, obtain the electronic energy loss spectrum dataset.
[0063] The test area of the sample is scanned pixel by pixel to acquire the raw electron energy loss spectrum dataset P. ij The region to be tested is the region where the grain boundary, phase boundary, or hole interface is located; i represents the row number of the pixel and j represents the column number of the pixel, and both i and j are positive integers greater than or equal to 1.
[0064] S40, electron energy loss spectrum centering processing.
[0065] For the electron energy loss spectrum dataset P ij The zero-loss peaks of the electron energy loss spectrum corresponding to each pixel are zeroed out to obtain the centered electron energy loss spectrum dataset A. ij .
[0066] In this application, "zeroing" means: reducing the electron energy loss spectrum dataset P ij The position of the zero-loss peak in the electron energy loss spectrum corresponding to each pixel is adjusted to 0eV.
[0067] S50, normalized peak intensity processing of electron energy loss spectrum.
[0068] Using the plasma peak with a peak position range of 15 eV to 23 eV in the electron energy loss spectrum as the reference peak, the electron energy loss spectrum dataset A was analyzed. ij The intensity of each spectral line plasma peak was normalized to obtain the electron energy loss spectrum dataset N after peak intensity normalization. ij .
[0069] Specifically, the number of pixels acquired during scanning is denoted as M. ij (i represents the row number of the pixel, j represents the column number of the pixel, and both i and j are positive integers greater than or equal to 1); using the electron energy loss spectrum dataset A ij Medium pixel M 11 Using the plasma peak intensities within the range of 15 eV to 23 eV in the electron energy loss spectrum as a benchmark, the electron energy loss spectrum dataset A was calculated. ij M for each pixel ij The ratio of the plasma peak intensity to the reference value, a ij ; The electron energy loss spectrum dataset A ij M for each pixel ij The intensity of the plasma peak in the electron energy loss spectrum divided by the corresponding a ij To ensure that the plasma peak intensities are the same, the electron energy loss spectrum dataset N after peak intensity normalization is obtained. ij .
[0070] As an example, when the peak intensity of the electron energy loss spectrum is normalized, the peak position value of the plasma peak in the electron energy loss spectrum can be any one of 15eV, 16eV, 17eV, 18eV, 19eV, 20eV, 21eV, 22eV and 23eV or a range between any two.
[0071] S60, extraction of plasma peak signal spectral lines.
[0072] In the electron energy loss spectrum dataset N ij We selected plasma peak signal lines with peak positions ranging from 15 eV to 23 eV in the electron energy loss spectrum and extracted the plasma peak signal spectral line dataset E. ij .
[0073] As an example, the plasma peak signal spectral line dataset E is extracted and obtained. ij At that time, the peak position value of the plasma in the electron energy loss spectrum can be any one of 15eV, 16eV, 17eV, 18eV, 19eV, 20eV, 21eV, 22eV and 23eV or any range between two of them.
[0074] S70, Gaussian smoothing of plasma peak signal spectral lines.
[0075] Data set E of plasma peak signal spectral lines ij Gaussian smoothing was performed to obtain the Gaussian smoothed plasma peak signal spectral line dataset S. ij .
[0076] S80, reading the peak position value of plasma peak signal spectrum and two-dimensional imaging.
[0077] Read the plasma peak signal spectral line dataset S ij The peak position of the intermediate ion peak signal spectrum line was obtained and two-dimensional imaging was performed using grayscale imaging. The grayscale value of the image reflects the degree of hydrogen absorption, thus obtaining the microscopic information of hydrogen distribution in the transmission electron microscope image of the metallic material.
[0078] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0079] Example 1 This embodiment provides an electron microscopy method for analyzing hydrogen distribution in metallic materials at nanoscale resolution. This method is used to analyze the hydrogen distribution information in the grain boundary region of a fully hydrogen-absorbed titanium hydride electron microscope sample. The specific steps are as follows: (1) Preparation and loading of transmission electron microscopy samples A thin sheet of titanium hydride with a thickness of 180 nm was prepared using a focused ion beam. During the final thinning process, argon ions were used to clean and thin both sides of the TEM sample until the surface of the TEM sample was free of gallium ions and carbon deposits and the thickness was 90 nm. The TEM sample was then mounted on the TEM sample holder.
[0080] The focusing ion beam microscope used was the Scios 2HiVac focusing ion beam microscope from Thermofisher Scientific, USA; the cleaning and thinning system used was the NanoMill 1040 microbeam site-specific ion thinning system from NanoMill, USA; and the transmission electron microscope used was the Themis Z double spherical aberration corrected transmission electron microscope from Thermofisher Scientific, USA.
[0081] (2) Optical path setup and analysis area selection for transmission electron microscopy Set the transmission electron microscope (TEM) optical path to scanning transmission dark field image mode, move the sample rod to center the thin-film TEM sample in the field of view, adjust to positive focus, and select the grain boundary region in the dark field image as the region of interest.
[0082] (3) Set up the optical path and scanning parameters for electron energy loss spectrum acquisition to obtain the electron energy loss spectrum dataset. The camera length was set to 37 mm, the aperture size of the condenser lens aperture was 50 μm, and the aperture size of the electron energy loss spectrum receiving aperture was 2.5 mm. The electron beam was moved into the imaging filter of the rear lens barrel, and the receiving aperture angle was set to 20.02 mrad according to the camera length and the aperture size of the electron energy loss spectrum receiving aperture.
[0083] Select the electron energy loss spectrum acquisition mode, set the acquisition step size to 2nm, and set the pixel acquisition time to 1s.
[0084] The test area of the sample is scanned pixel by pixel to acquire the raw electron energy loss spectrum dataset P. ij Where i represents the row number of the pixel and j represents the column number of the pixel, and both i and j are positive integers greater than or equal to 1.
[0085] (4) Electron energy loss spectrum centering processing For the original electronic energy loss spectrum dataset P ij The zero-loss peaks of the electron energy loss spectrum corresponding to each pixel are zeroed out (i.e., the peak positions are adjusted to 0 eV) to obtain the centered electron energy loss spectrum dataset A. ij .
[0086] (5) Normalization of electron energy loss spectrum peak intensity Using the plasma peak with a peak position range of 15 eV to 23 eV in the electron energy loss spectrum as the reference peak, the electron energy loss spectrum dataset A was analyzed. ij The intensity of each spectral line plasma peak was normalized to obtain the electron energy loss spectrum dataset N after peak intensity normalization. ij .
[0087] (6) Extraction of plasma peak signal lines In the electron energy loss spectrum dataset N ij We selected plasma peak signal lines with peak positions ranging from 15 eV to 23 eV in the electron energy loss spectrum and extracted the plasma peak signal spectral line dataset E. ij .
[0088] (7) Gaussian smoothing of plasma peak signal lines Data set E of plasma peak signal spectral lines ij Gaussian smoothing was performed to obtain the Gaussian smoothed plasma peak signal spectral line dataset S. ij .
[0089] (8) Reading of peak position values of plasma peak signal spectrum and two-dimensional imaging Read the plasma peak signal spectral line dataset S ij The peak position of the intermediate ion peak signal spectrum line was obtained and two-dimensional imaging was performed using grayscale imaging. The grayscale value of the image reflects the degree of hydrogen absorption, thus obtaining the microscopic information of hydrogen distribution in the transmission electron microscope image of the metallic material.
[0090] Figure 2 The image shows a scanning transmission dark-field image of the grain boundary region of a fully hydrogen-absorbed titanium hydride electron microscopy sample, with clear grain boundaries. Figure 3 The hydrogen distribution images with electron energy loss ranging from 15 eV to 23 eV are shown. It can be seen that the hydrogen distribution images obtained by this method have nanometer-level spatial resolution. The grain boundary interfaces in the images are clear, and the hydrogen concentration distribution of the grain boundaries and the grains on both sides can be displayed intuitively and clearly. Figure 3 The results show that, except for slightly larger peak values in some grain boundary regions, the peak values of the plasma in the entire analytical region are distributed within a relatively small range of 20.79 eV to 20.96 eV, indicating that the hydrogen distribution in fully hydrogen-absorbed titanium hydride is relatively uniform, consistent with the expected results. This result provides a nanometer-resolution microscopic distribution of hydrogen elements in the grain boundary regions of fully hydrogen-absorbed titanium hydride, revealing subtle differences in hydrogen distribution between grain boundaries and within grains, which is of great significance for revealing the hydrogen interface distribution characteristics of metallic materials.
[0091] Example 2 This embodiment provides an electron microscopy method for analyzing hydrogen distribution in metallic materials at nanoscale resolution. This method is used to analyze the hydrogen distribution information in the hydrogenated / unhydrogenated interface region of a titanium hydride electron microscopy sample that has not fully absorbed hydrogen. The specific steps are basically the same as in Example 1, with the following differences: The thickness of the transmission electron microscope sample obtained in step (1) is 85 nm.
[0092] In step (4), the acquisition step size of the electron energy loss spectrum acquisition mode is 35 nm.
[0093] Figure 4 The image shows a scanning transmission dark-field image of the hydrogenated / unhydrogenated interface region of an electron microscopy sample of titanium hydride that has not fully absorbed hydrogen; the interface is clearly visible. Figure 5 The hydrogen distribution images with electron energy loss ranging from 15 eV to 23 eV are shown. It can be seen that the hydrogen distribution images obtained by this method have nanoscale spatial resolution, and the interfaces in the images are clear, which can intuitively and clearly show the hydrogen concentration distribution on both sides of the interface. Figure 5 The results show that the hydrogen distribution at the interface is highly uneven. The plasma peak values in the hydrogenated region are very high, while the peak values in the unhydrogenated region are very low and the same as those in pure titanium. The peak values at the interface are in between, indicating that the sample gradually completes hydrogenation through interfacial diffusion, which is consistent with the expected results. This result provides microscopic information on the hydrogen distribution at the hydrogenated / unhydrogenated interface in titanium hydride that has not fully absorbed hydrogen, which is of great significance for revealing the hydrogen diffusion reaction mechanism in metallic materials.
[0094] In summary, the electron microscopy method for hydrogen distribution in metallic materials with nanoscale resolution provided in this application obtains high spatial resolution images of hydrogen distribution at the nanoscale by performing zero-loss peak alignment, peak intensity normalization, inductively coupled plasma (ICP) peak line extraction, ICP peak line smoothing, ICP peak position reading, and two-dimensional imaging on an electron energy loss spectrum set with nanoscale spatial resolution characteristics. The operation steps are simple and easy to implement, and the obtained hydrogen distribution images show clear regional boundaries, which can intuitively and clearly show the hydrogenation distribution characteristics inside the metallic material (such as the hydrogenation uniformity of hydrogenation in regions such as hydrogenated / unhydrogenated interfaces and grain boundaries). This method overcomes the problems of insufficient spatial resolution and large analytical errors introduced by tip sample preparation in existing methods. It can provide important information on hydrogen diffusion paths, hydrogen interface distribution characteristics, hydrogen absorption uniformity, and hydrogen absorption mechanisms in metallic materials, and has important implications for understanding the diffusion reaction mechanism of hydrogen in metallic materials.
[0095] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
Claims
1. An electron microscopy method for analyzing hydrogen distribution in metallic materials at nanoscale resolution, characterized in that, include: Load the sample to be tested into the transmission electron microscope; The sample to be tested is a metallic material; Select the electron energy loss spectral acquisition mode, and perform pixel-by-pixel scanning acquisition on the test area of the sample to obtain the original electron energy loss spectral dataset P. ij Wherein, the region to be tested is the region where the grain boundary is located, the region where the phase boundary is located, or the region where the hole interface is located; i represents the row number of the pixel, j represents the column number of the pixel, and i and j are both positive integers greater than or equal to 1; For the electron energy loss spectrum dataset P ij The zero-loss peaks of the electron energy loss spectrum corresponding to each pixel are zeroed out to obtain the centered electron energy loss spectrum dataset A. ij ; Using the plasma peak with a peak position range of 15 eV to 23 eV in the electron energy loss spectrum as the reference peak, the electron energy loss spectrum dataset A was analyzed. ij The intensity of each spectral line plasma peak was normalized to obtain the electron energy loss spectrum dataset N after peak intensity normalization. ij ; In the electron energy loss spectrum dataset N ij We selected plasma peak signal lines with peak positions ranging from 15 eV to 23 eV in the electron energy loss spectrum and extracted the plasma peak signal spectral line dataset E. ij ; For the plasma peak signal spectral line dataset E ij Gaussian smoothing was performed to obtain the Gaussian smoothed plasma peak signal spectral line dataset S. ij ; Read the plasma peak signal spectral line dataset S ij The peak position of the intermediate ion peak signal spectrum line was obtained and two-dimensional imaging was performed using grayscale imaging. The grayscale value of the image reflects the degree of hydrogen absorption, thus obtaining the microscopic information of hydrogen distribution in the transmission electron microscope image of the metallic material.
2. The electron microscopy method for hydrogen distribution in nanoscale resolution metallic materials according to claim 1, characterized in that, The optical path of the transmission electron microscope was set to scanning transmission dark field imaging mode.
3. The electron microscopy method for hydrogen distribution in nanoscale resolution metallic materials according to claim 1, characterized in that, The acquisition step size of the electron energy loss spectral acquisition mode is 1nm~50nm, and the acquisition time of the electron energy loss spectral acquisition mode for the pixel is 0.5s~2s.
4. The electron microscopy method for hydrogen distribution in nanoscale resolution metallic materials according to claim 1, characterized in that, Before performing the scanning acquisition, set the camera length, condenser aperture, and electron energy loss spectrum receiving aperture, move the electron beam into the rear lens barrel imaging filter, and set the receiving aperture angle.
5. The electron microscopy method for hydrogen distribution in nanoscale resolution metallic materials according to claim 4, characterized in that, The camera has a length of 29.5mm to 58mm.
6. The electron microscopy method for hydrogen distribution in nanoscale resolution metallic materials according to claim 4, characterized in that, The aperture size of the condenser lens is 20μm~70μm.
7. The electron microscopy method for hydrogen distribution in nanoscale resolution metallic materials according to claim 4, characterized in that, The aperture of the electron energy loss spectrum receiving aperture is 2.5 mm.
8. The electron microscopy method for hydrogen distribution in nanoscale resolution metallic materials according to claim 4, characterized in that, The receiving aperture angle is 12.78 mrad to 25.12 mrad.
9. The electron microscopy method for analyzing hydrogen distribution in nanoscale resolution metallic materials according to any one of claims 1 to 8, characterized in that, The thickness of the sample to be tested is 50nm~100nm.
10. The electron microscopy method for hydrogen distribution in nanoscale resolution metallic materials according to claim 9, characterized in that, The preparation method of the sample to be tested includes: firstly, preparing a transmission electron microscope sample with a thickness of 150nm~200nm using a focused ion beam microscope, and then reducing the thickness of the transmission electron microscope sample to 50nm~100nm using a microbeam fixed-point ion thinning system.