In-situ characterization electron microscope for material surface interface damage of multi-factor coupling corrosion

Abstract

The application provides an electron microscope for in-situ characterization of material surface and interface damage under multi-factor coupled corrosion, relates to the technical field of in-situ detection equipment, and aims at solving the technical problem that the scanning electron microscope in the prior art cannot realize the research on the damage mechanism of the material under a specific corrosion environment in-situ. The electron microscope for in-situ characterization of material surface and interface damage under multi-factor coupled corrosion comprises an electron microscope bin, a support frame, a corrosion-resistant loading table, a laser heating device and a gas needle. The corrosion-resistant loading table clamps a sample after salt spraying and applies stress to the sample. The laser heating device and the gas needle are integrated in the electron microscope bin. The sample is heated by the laser heating device, the hot salt environment under the stress state of the service of the sample is simulated, trace reaction gas is introduced to the surface of the sample through the gas needle, the test environment is closer to the actual environment, and thus the damage mechanism of the material under a specific environment is more truly revealed, thereby laying a foundation for establishing a hot, force and electrochemical multi-field coupled corrosion damage theory and a corrosion damage evaluation model.

Description

Technical Field

[0001] This invention relates to the field of in-situ testing equipment technology, specifically to an electron microscope used for in-situ characterization of material surface and interface damage in multi-factor coupled corrosion. Background Technology

[0002] Key components of major marine equipment operate under complex conditions involving high humidity, high salinity, temperature, and stress for extended periods, facing coupled corrosion damage from multiple fields including heat, force, and electrochemistry. In particular, the coupled effect of heat on force and salt in the marine atmospheric environment increases corrosion rates several times compared to single environmental factors, leading to nonlinear, unsteady, and accelerated material failure. However, current theories on multi-field coupled corrosion, especially in marine environments, are incomplete, and in-situ characterization and evaluation methods are severely lacking. This makes it difficult to accurately evaluate material corrosion behavior and elucidate its mechanisms, significantly hindering the development of high-safety service materials.

[0003] To simulate the marine atmospheric service environment, samples under controlled loads need to be placed in a thermosalinous environment, followed by X-ray diffraction analysis and morphological observation and micro-area composition testing in the same region using an electron microscope (scanning electron microscope). However, the high-vacuum environment of conventional electron microscopes is significantly different from the actual service environment of materials, leading to a discrepancy between the phenomena observed under the electron microscope and the actual situation. This is mainly because conventional electron microscopes cannot simulate the thermosalinous environment under stress conditions during material service and cannot truly reveal the damage mechanisms of materials under specific chemical environments. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide an electron microscope for in-situ characterization of material surface and interface damage in multi-factor coupled corrosion, thereby solving the technical problem that electron microscopes in the prior art cannot realize the study of damage mechanisms of materials under specific corrosion environments in situ.

[0005] To address the aforementioned technical problems, this invention provides an electron microscope for in-situ characterization of material surface and interface damage in multi-factor coupled corrosion, comprising:

[0006] Electron microscope chamber;

[0007] The support frame is located inside the electron microscope chamber;

[0008] A corrosion-resistant loading stage is mounted on a support frame and used for laterally clamping samples.

[0009] A non-contact optical heating device is located inside the electron microscope chamber and is used to heat the sample;

[0010] The gas needle is located inside the electron microscope chamber and is used to supply reaction gases to the sample.

[0011] With the above structure, the electron microscope for in-situ characterization of material surface and interface damage in multi-factor coupled corrosion of the present invention has the following advantages: the corrosion-resistant loading stage clamps the sample after salt spraying and applies stress to the sample; the non-contact optical heating device and the gas needle are integrated into the electron microscope chamber; the sample is heated by the non-contact optical heating device to simulate the thermo-salt environment under stress conditions of the sample in service; and a trace amount of reactive gas (such as oxygen) is introduced into the sample surface through the gas needle, making the test environment closer to the actual environment, thereby revealing the damage mechanism of the material under specific conditions more realistically, and laying the foundation for establishing a theory of multi-field coupled corrosion damage of thermo-mechanical and electrochemical factors and a corrosion damage assessment model.

[0012] As an improvement, the non-contact optical heating device is a laser heating device, which includes a laser coupler, an infrared thermometric fiber, a focusing lens assembly, a fixed-band reflector, and a total reflection mirror. The laser coupler and infrared thermometric fiber are both connected to the side wall of the electron microscope chamber. The focusing lens assembly is connected to one end of the support frame and includes a vertical section for connecting to the laser coupler and a horizontal section for connecting to the infrared thermometric fiber. The fixed-band reflector is connected inside the focusing lens assembly and located at the intersection of the extensions of the vertical and horizontal sections. The total reflection mirror is connected to the support frame and communicates with the focusing lens assembly through a channel on the support frame. The fixed-band reflector and the total reflection mirror are parallel to each other and both are angled at 45 degrees. A perforated section is provided at the bottom of the corrosion-resistant loading stage. The hollow section has a total reflection mirror located below it. With this structure, a fixed-band reflector allows infrared light to pass through while reflecting laser light. The laser light enters from the vertical section, is reflected by the fixed-band reflector and the total reflection mirror, and then shines onto the sample through the hollow section to heat the sample. Infrared light enters from the horizontal section, passes through the fixed-band reflector and is reflected by the total reflection mirror before shining onto the sample through the hollow section. The sample temperature is monitored in real time, allowing for temperature regulation. In X-ray diffraction, a two-dimensional galvanometer is typically used for heating to achieve heating at any location and higher temperature uniformity. The aforementioned laser heating device can achieve a heating state close to X-ray diffraction within the limited space of the electron microscope chamber, providing a basis for in-situ / quasi-in-situ testing in X-ray diffractometers and electron microscopes.

[0013] As an improvement, the present invention also includes a driving component and a cover plate. The cover plate has a through hole along its vertical edge. The driving component is connected to the cover plate and is used to drive the cover plate to move above the sample. A portion of the gas needle is embedded in the cover plate. The gas needle is tilted and its pinhole faces the sample. With this structure, under the bombardment of a high-energy electron beam, the high-temperature sample will generate a large number of diffuse thermal emission electrons, which will seriously interfere with the normal secondary electron signal, resulting in blurred images and reduced contrast. The cover plate, as a physical barrier, can effectively block and absorb the interfering thermal emission electrons from most areas of the sample (non-observation area), significantly improving the proportion of effective signal electrons and greatly improving the signal-to-noise ratio and clarity of electron microscopy images under high-temperature conditions, thus providing a guarantee for obtaining high-quality microstructure information.

[0014] As an improvement, the cover plate is made of high thermal conductivity copper, and the tail of the cover plate is a copper block with a first water channel connected to a liquid cooling device. With this structure, the copper block serves as a cooling structure, and water or liquid nitrogen can be introduced into the first water channel to act as a cold end of the electron microscope. This can adsorb impurities or salts that sublimate from the sample due to high temperature, preventing contamination and corrosion of the electron microscope.

[0015] As an improvement, the through-hole is a tapered hole with an upper inner diameter larger than the lower inner diameter. With this structure, the small opening at the lower end of the tapered hole can strictly limit the effective field of view of the detector, further eliminating electronic interference outside the observation area; while the large opening at the upper end provides more space for the electron beam to enter and the signal to exit, avoiding collisions with the cover plate. While effectively isolating background electronic noise, it maximizes the transmission of the observation signal, thereby obtaining high-temperature in-situ electron microscope images with better contrast and sharper details.

[0016] As an improvement, the electron microscope chamber is equipped with a motor stage, and the bottom of the support frame is equipped with a heat-insulating ceramic block. The support frame is connected to the motor stage through the heat-insulating ceramic block. The support frame is equipped with a second water channel, which is connected to a liquid cooling device. With this structure, the heat-insulating ceramic block prevents heat from being transferred to the motor stage, and the liquid cooling device can effectively remove the large amount of heat generated by laser heating, preventing the support frame and motor stage from thermal deformation or damage due to overheating.

[0017] As an improvement, the side wall of the electron microscope chamber is provided with an opening, which is connected to a slide valve for connection with the pre-extraction chamber; this structure establishes a fast and sealed sample transfer channel, which allows samples that have completed X-ray diffraction to be quickly transferred into the electron microscope chamber.

[0018] As an improvement, the slide gate valve is equipped with a connection structure for disengaging from the pre-extraction chamber. This structure achieves physical isolation between the electron microscope chamber and the external structure. During precise electron microscope observations, the connection can be disconnected to prevent external mechanical vibrations from interfering with electron microscope imaging, thereby obtaining clearer and more stable high-resolution images.

[0019] As an improvement, the connection structure includes a connecting plate, a fixing bolt, and a nut. The connecting plate is located on the pre-extraction chamber, the nut is located on the slide valve, and the fixing bolt passes through the connecting plate and is threadedly connected to the nut. This structure provides a simple, reliable, and low-cost detachable connection solution. The disassembly and assembly process is simple and quick, requiring no special tools.

[0020] As an improvement, the electron microscope chamber is equipped with a track located between the support frame and the slide valve. The upper end face of the support frame and the upper end face of the track are respectively provided with a first protrusion and a second protrusion, and the first protrusion and the second protrusion are coaxially arranged. The bottom end of the corrosion-resistant loading stage is provided with a groove that slides with the first protrusion and the second protrusion. With this structure, the magnetic rod in the traditional electron microscope cannot transport heavy objects. Therefore, by setting up a track to receive the corrosion-resistant loading stage after X-ray diffraction and transport it to the support frame, a basis is provided for realizing in-situ / quasi-in-situ testing in X-ray diffractometer and electron microscope. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0022] Figure 2 for Figure 1 Enlarged view of part A in the middle;

[0023] Figure 3 This is a schematic diagram of the through hole structure in this invention;

[0024] Figure 4 This is a top view of the track section in this invention;

[0025] Figure 5 This is a schematic diagram of the corrosion-resistant loading stage in this invention;

[0026] Figure 6 This is a three-dimensional structural diagram of the support frame and focusing lens assembly in this invention;

[0027] Figure 7 This is a three-dimensional structural diagram of the support frame and focusing lens assembly in this invention from another perspective.

[0028] Reference numerals: 1. Electron microscope chamber; 2. Support frame; 3. Corrosion-resistant loading stage; 4. Drive assembly; 5. Cover plate; 6. Through hole; 7. Motor stage; 8. Slide valve; 9. Track; 10. Second protrusion; 11. Groove; 12. Gas needle; 13. Laser coupler; 14. Infrared temperature measurement fiber optic cable; 15. Focusing lens assembly; 151. Vertical section; 152. Horizontal section; 16. Total reflection mirror; 17. Thermal insulation ceramic block; 18. Second water channel. Detailed Implementation

[0029] The following is a detailed description of the electron microscope for in-situ characterization of material surface and interface damage in multi-factor coupled corrosion, based on the accompanying drawings.

[0030] like Figures 1 to 7 As shown, the electron microscope used for in-situ characterization of material surface and interface damage in multi-factor coupled corrosion includes an electron microscope chamber 1, a support frame 2, a corrosion-resistant loading stage 3, a non-contact optical heating device, and a gas needle 12. The support frame 2 is located inside the electron microscope chamber 1. Specifically, the electron microscope chamber 1 is equipped with a motor stage 7, and the support frame 2 is connected to the motor stage 7. The motor stage 7 drives the support frame 2 to move and position precisely. The specific structure and working principle of the motor stage 7 are existing technologies and will not be described in detail here.

[0031] like Figure 1 and Figure 2 As shown, the corrosion-resistant loading stage 3 is mounted on the support frame 2 and is used to clamp the sample laterally. The corrosion-resistant loading stage 3 is equipped with a drive shaft with two sections of threaded sections with opposite directions of rotation. Two movable seats are threadedly connected to the drive shaft. The drive shaft is driven to rotate by a motor, so that the two movable seats clamp the sample and can apply stress to the sample.

[0032] like Figure 1 As shown, the side wall of the electron microscope chamber 1 has an opening, which is connected to a gate valve 8 for connecting to the pre-evacuation chamber. The pre-evacuation chamber is separated from the electron microscope chamber 1 and placed outside the electron microscope chamber 1. The gate valve 8 controls the opening and closing of the electron microscope chamber 1 and the pre-evacuation chamber. The sample that has undergone X-ray diffraction in the X-ray diffractometer is held by the corrosion-resistant loading stage 3, pre-evacuated in the pre-evacuation chamber, and then enters the electron microscope chamber 1 through the gate valve 8, providing a basis for in-situ / quasi-in-situ testing in the X-ray diffractometer and electron microscope.

[0033] Based on this, such as Figure 1 and Figure 2 As shown, the electron microscope chamber 1 is equipped with a track 9 located between the support frame 2 and the slide valve 8; Figure 4 and Figure 5 As shown, the upper surface of the support frame 2 and the upper surface of the track 9 are respectively provided with a first protrusion and a second protrusion 10, and the first protrusion and the second protrusion 10 are coaxially arranged, that is, the first protrusion is located on the extension line of the second protrusion 10. The bottom end of the corrosion-resistant loading stage 3 is provided with a groove 11 that slides with the first protrusion and the second protrusion 10. By setting the track 9 in the electron microscope chamber 1 to replace the magnetic rod in the traditional electron microscope, the corrosion-resistant loading stage 3 transferred from the pre-extraction chamber after X-ray diffraction is completed can be received, so that the sample after X-ray diffraction can be subjected to secondary electron and energy dispersive spectroscopy tests in the electron microscope.

[0034] In addition, the slide gate valve 8 is provided with a connection structure for disengaging from the pre-extraction chamber. The connection structure includes a connecting plate, a fixing bolt, and a nut. The connecting plate is located on the pre-extraction chamber, the nut is located on the slide gate valve 8, and the fixing bolt passes through the connecting plate and is threadedly connected to the nut. When performing precise electron microscopy observations, the connection structure can be used to disconnect the connection to prevent external mechanical vibrations from interfering with electron microscopy imaging, thereby obtaining clearer and more stable high-resolution images.

[0035] A non-contact optical heating device is located inside the electron microscope chamber 1 and is used to heat the sample; specifically, such as... Figure 1 and Figure 2 As shown, the non-contact optical heating device is a laser heating device, which includes a laser coupler 13, an infrared temperature measuring fiber 14, a focusing lens assembly 15, a fixed-band reflector, and a total reflection mirror 16. Both the laser coupler 13 and the infrared temperature measuring fiber 14 are connected to the side wall of the electron microscope chamber 1. Figure 6 As shown, the focusing lens assembly 15 is connected to one end of the support frame 2. The focusing lens assembly 15 includes a vertical section 151 for connecting to the laser coupler 13 and a horizontal section 152 for connecting to the infrared temperature measuring fiber optic 14. A fixed-band reflector is connected inside the focusing lens assembly 15 and is located at the intersection of the extension lines of the vertical section 151 and the horizontal section 152. A total reflection mirror 16 is connected to the support frame 2 and communicates with the focusing lens assembly 15 through a channel on the support frame 2. The fixed-band reflector and the total reflection mirror 16 are parallel to each other and are both set at a 45-degree angle. A hollow part is provided through the bottom end of the corrosion-resistant loading stage 3, and the total reflection mirror 16 is located below the hollow part.

[0036] A fixed-band reflector allows infrared light to pass through while reflecting laser light. The laser light enters from the vertical section 151, is reflected by the fixed-band reflector and the total reflection mirror 16, and then shines onto the sample through the hollow section to heat the sample. Infrared light enters from the horizontal section 152, passes through the fixed-band reflector and is reflected by the total reflection mirror 16, and then shines onto the sample through the hollow section to detect the sample temperature in real time, thereby achieving temperature regulation. In X-ray diffraction, a two-dimensional galvanometer is generally used for heating to achieve heating at any position and to have higher temperature uniformity. The laser heating device described above can achieve a heating state close to X-ray diffraction within the limited space of the electron microscope chamber 1, mainly in terms of heating position and heating temperature. This provides a basis for in-situ / quasi-in-situ testing in X-ray diffractometers and electron microscopes. The laser used in the electron microscope is a semiconductor laser, and the total reflection mirror 16 is a square shaped quartz glass, so that the shape of the light spot is the same as that of the X-ray diffraction light spot. Among them, the fixed-band reflector can be finely adjusted in the front-to-back direction, and the total reflection mirror 16 can be finely adjusted in the left-to-right direction, so as to ensure that the light spot illuminates the sample. The specific structures of the fixed-band reflector and the total reflection mirror 16 are existing technologies and will not be described in detail here.

[0037] In addition, such as Figure 7As shown, the bottom of the support frame 2 is provided with a heat-insulating ceramic block 17. The support frame 2 is connected to the motor platform 7 through the heat-insulating ceramic block 17. The support frame 2 is provided with a second water channel 18, which is connected to a liquid cooling device. The heat-insulating ceramic block 17 prevents heat from being transferred to the motor platform 7, and the liquid cooling device can effectively remove the large amount of heat generated by laser heating, preventing the support frame 2 and the motor platform 7 from thermal deformation or damage due to overheating.

[0038] The gas needle 12 is located inside the electron microscope chamber 1 and is used to supply the sample with a reaction gas, such as oxygen.

[0039] The invention also includes a driving component 4 and a cover plate 5. The cover plate 5 has a through hole 6 along its vertical edge. The through hole 6 is a conical hole with an upper inner diameter larger than its lower inner diameter. The driving component 4 is connected to the cover plate 5 and is used to drive the cover plate 5 to move above the sample. Under the bombardment of a high-energy electron beam, the high-temperature sample will generate a large number of diffuse thermal emission electrons, which will seriously interfere with the normal secondary electron signal, resulting in blurred images and reduced contrast. The cover plate 5, as a physical barrier, can effectively block and absorb interfering thermal emission electrons from most areas of the sample (non-observation area), significantly improving the proportion of effective signal electrons and greatly improving the signal-to-noise ratio and clarity of electron microscope images under high-temperature conditions. This provides a guarantee for obtaining high-quality microstructure information. The small opening at the lower end of the conical hole can strictly limit the effective acquisition field of the detector and further eliminate electron interference outside the observation area. The large opening at the upper end provides more space for the electron beam to enter and the signal to exit, avoiding collisions with the cover plate 5. While effectively isolating background electron noise, it maximizes the transmission of the observation signal, thereby obtaining high-temperature in-situ electron microscope images with better contrast and sharper details.

[0040] A portion of the gas needle 12 is embedded in the cover plate 5. Specifically, a portion of the gas needle 12 is embedded above or below the cover plate 5, moving in and out synchronously with the cover plate 5. The gas needle 12 is tilted and its needle hole faces the sample. The gas needle 12 is connected to a pressure reducing valve and a needle valve, and has a flow control function, allowing the introduction of reaction gas as needed. The cover plate 5 is made of high thermal conductivity copper. The tail of the cover plate 5 is a copper block with a first water channel. The first water channel is connected to a liquid cooling device. The copper block serves as a cooling structure. Water or liquid nitrogen can be introduced into the first water channel, which acts as a cold end of the electron microscope. It can adsorb impurities or salts that sublimate from the sample due to high temperature, preventing contamination and corrosion of the electron microscope.

[0041] After the corrosion-resistant loading stage 3 is moved onto the support frame 2, the slide valve 8 is closed, disconnecting the electron microscope chamber 1 from the pre-evacuation chamber. At the same time, the laser heating device is turned on to maintain the original experimental temperature (the temperature during X-ray diffraction). The gas needle 12 is turned on to add a trace amount of oxygen. The electron microscope is used to collect corrosion product information in situ / quasi-situ high-temperature secondary electron and energy dispersive spectroscopy, making the test environment closer to the actual environment. This allows for a more realistic revelation of the damage mechanism of materials under specific conditions, laying the foundation for establishing a theory of corrosion damage and a corrosion damage assessment model based on the multi-field coupling of thermo-mechanical and electrochemical fields.

[0042] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiment. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. An electron microscope for in-situ characterization of material surface and interface damage in multi-factor coupled corrosion, characterized in that, include: Electron microscope chamber (1); The support frame (2) is located inside the electron microscope chamber (1); A corrosion-resistant loading stage (3) is provided on the support frame (2) and is used to hold the sample laterally; A non-contact optical heating device is installed inside the electron microscope chamber (1) and used to heat the sample; A gas needle (12) is placed inside the electron microscope chamber (1) and is used to supply reaction gas to the sample; It also includes a drive assembly (4) and a cover plate (5). The cover plate (5) has a through hole (6) along its vertical direction. The drive assembly (4) is connected to the cover plate (5) and is used to drive the cover plate (5) to move above the sample. A part of the gas needle (12) is embedded in the cover plate (5). The gas needle (12) is tilted and the needle hole of the gas needle (12) faces the sample. The cover plate (5) is made of high thermal conductivity copper material. The tail of the cover plate (5) is a copper block with a first water channel. The first water channel is connected to a liquid cooling device. The copper block serves as a cooling structure. Water or liquid nitrogen is introduced into the first water channel to adsorb impurities or salts that sublimate at high temperature at the sample end of the electron microscope, thus preventing contamination and corrosion of the electron microscope. The support frame (2) has a heat-insulating ceramic block (17) at the bottom and a second water channel (18) inside the support frame (2), which is connected to a liquid cooling device.

2. The electron microscope for in-situ characterization of material surface and interface damage for multi-factor coupled corrosion as described in claim 1, characterized in that, The non-contact optical heating device is a laser heating device, which includes a laser coupler (13), an infrared temperature measuring fiber (14), a focusing lens assembly (15), a fixed-band reflector, and a total reflection mirror (16). The laser coupler (13) and the infrared temperature measuring fiber (14) are both connected to the side wall of the electron microscope chamber (1). The focusing lens assembly (15) is connected to one end of the support frame (2). The focusing lens assembly (15) includes a vertical section (151) for connecting to the laser coupler (13) and a section for connecting to the infrared temperature measuring fiber (14). The fixed-band reflector is connected to the horizontal segment (152) and is located at the intersection of the extension line of the vertical segment (151) and the extension line of the horizontal segment (152). The total reflection mirror (16) is connected to the support frame (2) and communicates with the focusing mirror assembly (15) through the channel on the support frame (2). The fixed-band reflector and the total reflection mirror (16) are parallel to each other and are both set at a 45-degree angle. The bottom end of the corrosion-resistant loading stage (3) is provided with a hollow part, and the total reflection mirror (16) is located below the hollow part.

3. The electron microscope for in-situ characterization of material surface and interface damage for multi-factor coupled corrosion as described in claim 1, characterized in that, The through hole (6) is a tapered hole with an upper inner diameter larger than the lower inner diameter.

4. The electron microscope for in-situ characterization of material surface and interface damage for multi-factor coupled corrosion according to claim 1, characterized in that, The electron microscope chamber (1) is equipped with a motor stage (7), and the support frame (2) is connected to the motor stage (7) through the heat-insulating ceramic block (17).

5. The electron microscope for in-situ characterization of material surface and interface damage according to claim 1, characterized in that, The electron microscope chamber (1) has an opening on its side wall, and the opening is connected to a slide valve (8) for connection with the pre-extraction chamber.

6. The electron microscope for in-situ characterization of material surface and interface damage according to claim 5, characterized in that, The slide gate valve (8) is provided with a connection structure for being detachably connected to the pre-extraction chamber.

7. The electron microscope for in-situ characterization of material surface and interface damage for multi-factor coupled corrosion according to claim 6, characterized in that, The connection structure includes a connecting plate, a fixing bolt, and a nut. The connecting plate is located on the pre-extraction chamber, the nut is located on the slide valve (8), and the fixing bolt passes through the connecting plate and is threadedly connected to the nut.

8. The electron microscope for in-situ characterization of material surface and interface damage according to claim 5, characterized in that, The electron microscope chamber (1) is provided with a track (9) located between the support frame (2) and the slide valve (8). The upper end face of the support frame (2) and the upper end face of the track (9) are respectively provided with a first protrusion and a second protrusion (10), and the first protrusion and the second protrusion (10) are coaxially arranged. The bottom end of the corrosion-resistant loading stage (3) is provided with a groove (11) that slides with the first protrusion and the second protrusion (10).

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