Detection method of marine corrosion primary process

Abstract

The invention relates to a method for detecting a marine corrosion primary process, which comprises the following steps of: constructing three vacuum chambers and connecting the three vacuum chambers by using vacuum pipelines to form a detection system; ultrafast femtosecond laser with the repetition frequency being 1 kHz, the single pulse energy being 6 mJ, the pulse width being 35 fs and the central wavelength being 800 nm is generated through a pulse amplifier; one beam of 2mJ enters a vacuum chamber pipeline to be transmitted as a pulse light beam for detection in the original process of ocean corrosion, the other beam of 4mJ is transmitted outside the vacuum chamber to be used as a pump pulse light beam, and 400 nm pump pulse laser is generated through frequency doubling of a BBO crystal; the pump light beam and the detection light beam are incident on a sample of a sample mechanism in the third vacuum chamber, then the pump light beam is blocked, and only the detection light beam is incident on the sample; xUV light beams reflected from the sample are subjected to spectral dispersion and then enter a CCD detector, and the dynamic response of the sample after being excited by the pump light is monitored by measuring the transmissivity, reflectivity or absorption change of the surface of the sample.

Description

Technical Field

[0001] The present invention relates to the field of laser detection, and particularly to a method for detecting the primary process of marine corrosion. Background Art

[0002] Relative to the external environment, a smooth metal surface is usually in a thermodynamically unstable state. Once in contact with the environmental solution, a corrosion-self-healing process on the picosecond time scale occurs on the metal surface. The surface metal atoms are stripped from the substrate to form metal ions, leading to corrosion, while the formation of surface compounds and the evolution of oxides trigger the self-healing process of the metal surface. The density of the metal surface oxide and its bonding strength with the metal substrate determine the rate of the metal corrosion process. A dense oxide surface film can form an isolation zone between the metal substrate and the solution environment, alleviating or even preventing the re-corrosion of the metal, that is, the self-healing process of the metal surface.

[0003] Therefore, the prevention of the metal corrosion process and the intervention of the surface self-healing process are the keys to alleviating or even preventing the metal re-corrosion process, and also the entry points for in-depth exploration of corrosion mechanisms such as stress corrosion, pitting corrosion, hydrogen embrittlement corrosion, and crevice corrosion. A large amount of data shows that the corrosion of metals will form serious safety hazards and cause huge economic losses. Therefore, studying the changes at the solid / liquid interface during the metal corrosion-self-healing process has very important scientific significance and economic value.

[0004] However, limited by the development of research technical means, there are not many in-situ research reports on the changes at the solid / liquid interface during the metal corrosion-self-healing process at present. Common surface technology research means such as X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED), etc. need to be carried out in a high-vacuum environment, and it is very difficult to carry out in-situ experiments. For more common Raman spectroscopy, due to the need for signal enhancement, high selectivity of the research system, and low time resolution (millisecond, ms), it limits the application of this technology in the study of the changes at the solid / liquid interface during the metal corrosion-self-healing process. Femtosecond sum frequency generation spectroscopy (FS-SFG) with high spatio-temporal resolution is difficult to capture the reaction signals of the changes at the solid / liquid interface during the metal corrosion-self-healing process due to its narrow atomic pair vibration sensitivity. In recent years, ambient pressure X-ray photoelectron spectroscopy (AP-XPS), X-ray standing wave + X-ray photoelectron spectroscopy (SWAPPS), and white light X-ray absorption spectroscopy (DXAFS) have realized the in-situ detection of the changes at the solid / liquid interface process, but these methods need to rely on huge synchrotron radiation devices and it is very difficult to carry out ultrafast in-situ detection. Therefore, it is extremely urgent to develop experimental technical means that can in-situ detect the changes at the solid / liquid interface during the metal corrosion-self-healing process on an ultrafast time scale (fs).

[0005] The fs-ms process during the whole corrosion process is as Figure 1As shown, the initial process of marine corrosion is accompanied by physical and chemical reactions such as the formation and breakage of chemical bonds, structural phase transitions, electron vibration rotation and transport, and multi-degree-of-freedom interactions. These processes all occur within a time scale of hundreds of femtoseconds and a spatial scale of the order of angstroms. For example, Figure 2 As shown, existing high-speed cameras, ICCD cameras, streak cameras, etc. are all unable to detect the fs stage. Therefore, there is an urgent need to design a detection method that can detect the initial process of marine corrosion in the fs stage. Summary of the Invention

[0006] The object of the present invention is to provide a detection method for the initial process of marine corrosion. Using the femtosecond pump-probe technique, a femtosecond pulsed laser beam is used as the pump laser to excite the material, and another pulsed laser beam is used as the probe light to enter the imaging or receiving device after passing through the area irradiated by the pump laser on the target material. Among them, the time when the probe light passes through the target material is later than the time when the pump light reaches the target material, which can realize the detection of ultrafast phenomena. The time resolution can reach the fs level, and it can well detect the initial process of marine corrosion.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a detection method for the initial process of marine corrosion, including the following steps: Step 1: Build three vacuum chambers and connect them with vacuum pipes to form a detection system for the initial process of marine corrosion. The minimum pressure of the vacuum chamber is 10-9 Torr. A sample mechanism for placing samples is provided in the third vacuum chamber, and a CCD detector is equipped; Step 2: Generate an ultrafast femtosecond laser with a repetition frequency of 1 kHz, a single-pulse energy of 6 mJ, a pulse width of 35 fs, and a central wavelength of 800 nm through a pulse amplifier; Step 3: Split the ultrafast femtosecond laser beam with a central wavelength of 800 nm and a pulse energy of 6 mJ. One beam of 2 mJ enters the vacuum chamber pipeline for transmission as the pulsed beam for detecting the initial process of ocean corrosion, and the other beam of 4 mJ is transmitted outside the vacuum chamber as the pump pulsed beam; the 800 nm, 2 mJ laser pulse entering the vacuum pipeline is focused into a gas chamber with a length of 40 cm filled with neon gas at a pressure of 75 Torr through a lens with a focal length of 70 cm, and high-order harmonic generation is realized by interacting with neon gas. The generated high-order harmonic wavelength is in the XUV band, and the photon energy range is 36-72 eV, and it enters the first vacuum chamber for further transmission. The generated high-order harmonic in the XUV band is used as the detection beam of the detection system for the initial process of marine corrosion. The 4 mJ pump pulsed beam transmitted outside the vacuum chamber is frequency-doubled through a BBO crystal to generate a pump pulsed laser of 400 nm, and this wavelength can produce transition resonance with the metal to be detected; Step 4: Both the pump beam and the probe beam are incident on the sample of the sample mechanism in the third vacuum chamber. After that, the pump beam is blocked, and only the probe beam is incident on the sample. Step 5: Use an aberration-corrected concave variable line-spacing grating to spectroscopically disperse the XUV beam reflected from the sample and then enter the CCD detector. At the same time, collect the reflected pump beam to prevent any stray light from reaching the CCD detector. By measuring the changes in optical properties such as transmittance, reflectance, or absorption on the sample surface, monitor the dynamic response of the sample after being excited by the pump light.

[0008] Preferably, the time when the probe light passes through the target material is later than the time when the pump light reaches the target material.

[0009] Preferably, the probe beam in the XUV band enters the second vacuum chamber from the first vacuum chamber, and the beam is focused on the sample surface of the third vacuum chamber through an annular mirror in the second vacuum chamber.

[0010] Preferably, the incident angle of the probe beam in the XUV band on the sample is 82° relative to the surface normal, and the beam size (FWHM) on the sample is 1.01 ± 0.02 mm and 0.137 ± 0.002 mm on the tangential axis and the sagittal axis, respectively.

[0011] Preferably, the 400 nm pump beam is incident on the sample at an angle of 70° relative to the sample surface normal, and the pump area is 2.43 mm 2 。

[0012] Preferably, after one detection, the sample mechanism drives the sample thereon to translate or rotate to change different detection points.

[0013] The new light source based on the ultra-intense laser can generate ultrafast XUV and X-ray pulses with a pulse length on the femtosecond scale and a brightness comparable to that of synchrotron radiation. It has the characteristics of miniaturization of the instrument, ultrashort pulses, and a wide frequency band range, and is very suitable for carrying out ultrafast in-situ detection of the change process at the solid / liquid interface. Therefore, use the ultra-intense laser to generate ultrafast XUV and X-ray pulse radiation, in-situ measure the scattering and energy-dispersive line absorption spectra of the metal corrosion interface, and in-situ detect the changes in the elemental composition, structural characteristics, and chemical properties of the metal / solution interface during the metal corrosion-self-healing process on the hundred-femtosecond time scale, and establish a process model for the formation of metal ions when metal atoms enter the solution from the metal matrix, a model for the formation of metal oxides and their attachment and growth on the metal matrix surface, and a model for the initiation and propagation of pitting corrosion during the metal matrix corrosion process.

[0014] The technical effects of the present invention are as follows: 1. The femtosecond pump-probe technique is adopted. A femtosecond pulsed laser beam is used as the pump laser to excite the material, and another pulsed laser beam is used as the probe light. After passing through the area irradiated by the pump laser on the target material, the probe light enters the imaging or receiving device. Among them, the time when the probe light passes through the target material is later than the time when the pump light reaches the target material, enabling the detection of ultrafast phenomena. The time resolution can reach the fs level, and it can well detect the initial process of marine corrosion.

[0015] 2. The irradiation of the pump beam on the sample surface causes the excitation and relaxation of microscopic particles such as electrons and phonons inside the material, and can complete the seawater attachment on the sample surface in the sample mechanism, and can better simulate the initial process of marine corrosion. Description of the Drawings

[0016] Figure 1 It is a process diagram of fs-ms during the whole corrosion process.

[0017] Figure 2 It is a schematic diagram of the time resolution of the detection means.

[0018] Figure 3 It is a diagram of the detection system.

[0019] Figure 4 It is a schematic diagram of the structure of the sample mechanism.

[0020] Figure 5 It is a schematic diagram of the structure of the drip device.

[0021] Figure 6 It is a schematic diagram of the retracting and deploying structure.

[0022] Figure 7 It is for Figure 6 The sectional view taken along B-B in

[0023] Figure 8 It is a schematic diagram of the structure of the sample-carrying device.

[0024] Figure 9 It is a schematic diagram of the sample-carrying adjustment structure.

[0025] The text annotations shown in the figure are as follows: 1. Sample box; 2. Sample loading device; 3. Sample plate; 4. Excitation interface; 5. Detection interface; 6. Detection port; 7. Dripping device; 11. Three-way joint; 12. Vacuum pump; 13. Sealing cover; 14. Dripping joint; 15. Dripping hose; 16. Dripping head; 17. Pulling rope; 18. Retracting and releasing structure; 19. Retracting and releasing mounting frame; 20. Retracting and releasing motor; 21. Retracting and releasing cylinder; 22. Retracting and releasing clamping bolt; 31. Sample support; 32. Sample loading mounting seat; 33. Waterproof cover; 34. Sample loading adjustment motor; 35. Sample loading adjustment screw rod; 36. Sample loading adjustment slide rail; 37. Sample loading adjustment movable block; 38. Sample loading adjustment seat; 39. Sample loading rotation motor; 40. Sample loading rotation seat; 41. Sample loading limit rod; 42. Sample loading screw; 43. Sample loading locking nut. Detailed implementation mode

[0026] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings. The description of this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present invention. Embodiment 1

[0027] A detection method for the primary process of marine corrosion includes the following steps: Step 1: Build three vacuum chambers and connect them with vacuum pipelines to form a detection system for the primary process of marine corrosion, as roughly shown in Figure 3 shown. The minimum pressure of the vacuum chamber is 10-9 Torr. A sample mechanism for placing samples is provided in the third vacuum chamber, and a CCD detector is equipped; Step 2: Generate an ultrafast femtosecond laser with a repetition frequency of 1 kHz, a single pulse energy of 6 mJ, a pulse width of 35 fs, and a central wavelength of 800 nm through a pulse amplifier; Step 3: Split the ultrafast femtosecond laser beam with a central wavelength of 800 nm and a pulse energy of 6 mJ. One beam of 2 mJ enters the vacuum chamber pipeline for transmission as the pulsed beam for detection in the detection of the primary process of ocean corrosion, and the other beam of 4 mJ is transmitted outside the vacuum chamber as the pump pulse beam; the 800 nm, 2 mJ laser pulse entering the vacuum pipeline is focused into a gas chamber with a length of 40 cm filled with neon gas at a pressure of 75 Torr through a lens with a focal length of 70 cm, and interacts with neon gas to generate high-order harmonics. The generated high-order harmonic wavelength is in the XUV band, and the photon energy range is 36-72 eV, and enters the first vacuum chamber for further transmission. The generated high-order harmonics in the XUV band are used as the detection beam of the detection system for the primary process of marine corrosion. The detection beam in the XUV band enters the second vacuum chamber from the first vacuum chamber, and the beam is focused on the sample surface of the third vacuum chamber through an annular mirror in the second vacuum chamber; The 4 mJ pump pulse beam transmitted outside the vacuum chamber is frequency-doubled by a BBO crystal to generate a 400 nm pump pulse laser, and this wavelength can produce transition resonance with the metal to be detected; Step 4: Both the pump beam and the probe beam are incident on the sample of the sample mechanism in the third vacuum chamber. The time for the probe light to pass through the target material is later than the time for the pump light to reach the target material. And the incident angle of the XUV band probe beam on the sample is 82° relative to the surface normal. The beam size (FWHM) on the sample is 1.01 ± 0.02 mm and 0.137 ± 0.002 mm on the tangential axis and sagittal axis respectively; the 400 nm pump beam is incident on the sample at an angle of 70° relative to the sample surface normal, and the pump area is 2.43 mm 2 , and then the pump beam is blocked, and only the probe beam is incident on the sample; Step 5: Use an aberration-corrected concave variable line-spacing grating to spectroscopically disperse the XUV beam reflected from the sample and then enter the CCD detector. At the same time, collect the reflected pump beam to prevent any stray light from reaching the CCD detector; by measuring the changes in optical properties such as transmittance, reflectance, or absorption on the sample surface, monitor the dynamic response of the sample after being excited by the pump light. Example 2

[0028] Compared with Example 1, after one detection is completed, the sample is moved by the sample mechanism. Each time it is moved, one detection is performed, and a set of spectral data is collected, and then multi-point detection is carried out. Example 3

[0029] Compared with Example 2, during the multi-point detection process, each time detection is performed, adjust the parameters of the pump beam and the probe beam, such as wavelength, pulse width, and energy. Example 4

[0030] Compared with Example 1, the structure of the sample mechanism is specifically disclosed As Figures 4-5 shown, the sample mechanism includes a sample box 1. Inside the sample box 1, there is a sample loading device 2 for placing a sample plate 3 and a water dripping device 7. On one side of the sample box 1, there is an excitation interface 4 and a detection interface 5. The water dripping device 7 includes a communication port opened on the upper part of the sample box 1. The upper part of the communication port is connected with a three-way joint 11. The other two interfaces of the three-way joint 11 are respectively used for air extraction and water dripping. The air extraction interface is connected to a vacuum pump 12, and the water dripping interface is equipped with a plugging cover 13. On the inner upper plate of the sample box 1, there is a water dripping joint 14 that cooperates with the communication port. The water dripping joint 14 is connected with a water dripping hose 15. The lower end of the water dripping hose 15 is connected with a water dripping head 16, and the water dripping head 16 is a metal heavy tube, and the water dripping head 16 is connected with a pull rope 17. The upper end of the pull rope 17 is connected with a retracting and releasing structure 18 inside the sample box 1.

[0031] The sample box 1 is opened, the sample plate 3 is placed on the sample loading device 2, and then the sample box 1 is closed. Then, the plugging cover 13 is opened, and seawater (or a water solution with seawater corrosion properties) is dripped into the three-way joint 11 from the dripping interface. Since the dripping head 16 is a metal heavy tube, when there is no acting force on the pulling rope 17, the dripping hose 15 is in a vertical state, and the seawater will fall onto the sample plate 3 from top to bottom, putting the sample plate 3 in a state of seawater corrosion. Then, the pulling rope 17 is wound by the winding and unwinding structure 18, causing the dripping head 16 to rise. In this way, the dripping hose 15 is in an arc state. Then, the plugging cover 13 is closed again, and then the vacuum pump 12 is started to pump air into the sample box 1 from the three-way joint 11. As the vacuum pumping progresses, a vacuum environment will be formed in the sample space, pulling the dripping hose into an arc shape, which can avoid interfering with laser detection. After the seawater simulation of the above sample is completed, the detection operation of Example 1 is carried out. Example 5

[0032] Compared with Example 4, in this example, the winding and unwinding structure is specifically defined as follows Figures 7-8 As shown, the winding and unwinding structure 18 includes a winding and unwinding motor 20 installed on the upper part of the sample box 1. The winding and unwinding motor 20 is connected with a winding and unwinding cylinder 21. One end of the pulling rope 17 is fixed on the winding and unwinding cylinder 21. The winding and unwinding motor 20 is installed on the winding and unwinding mounting frame 19, and the winding and unwinding mounting frame 19 is installed on the inner wall of the sample box 1 through bolts. The rotating shaft of the winding and unwinding motor 20 is connected with the winding and unwinding cylinder 21 through a winding and unwinding clamping bolt 22.

[0033] In this example, the winding and unwinding structure is integrally installed on the side upper wall of the sample box 1 through the winding and unwinding mounting frame 19. Then, the pulling rope 17 is fixed to the winding and unwinding cylinder 21. Then, the winding and unwinding motor 20 drives the winding and unwinding cylinder 21 to rotate, so that the pulling rope 17 can be wound and unwound. Similarly, for the winding and unwinding structure of the present application, the winding and unwinding cylinder 21 and the output shaft of the winding and unwinding motor 20 can be disassembled by removing the winding and unwinding clamping bolt 22. Example 6

[0034] As Figures 8-9As shown in the figure, this embodiment specifically describes the structure of the sample loading device 2. The sample loading device 2 includes a sample mounting base 32 disposed in the sample box 1. A sample loading adjustment structure is provided on the sample mounting base 32. The sample plate 3 is mounted on the sample loading adjustment structure, and different parts on the sample plate 3 are coordinated with the detection laser and the excitation laser through the sample loading adjustment structure. A waterproof cover 33 is mounted on the sample mounting base 32, and the waterproof cover 33 is located below the sample plate 3 and surrounds the sample loading adjustment structure. The sample loading adjustment structure includes a sample loading adjustment motor 34. The sample loading adjustment motor 34 drives a sample loading adjustment lead screw 35. The sample loading adjustment lead screw 35 is sleeved and fitted with a sample loading adjustment movable block 37. The sample loading adjustment movable block 37 is coordinated with a sample loading adjustment slide rail 36 provided on the sample mounting base 32. A sample loading adjustment seat 38 is provided on the sample loading adjustment movable block 37. A sample loading rotation motor 39 is provided on the sample loading adjustment seat 38. The sample loading rotation motor 39 is connected to a sample loading rotation seat 40. The sample plate 3 is fixed on the sample loading rotation seat 40. A sample support 31 is mounted below the sample plate 3 by bolts. The sample support 31 is in an inverted conical shape, and the lower part of the sample support 31 is a flat plate and is located on the sample loading rotation seat 40. A sample loading screw 42 is provided at the center of the sample loading rotation seat 40. The sample loading screw 42 passes through the lower flat plate of the sample support 31, and the sample support 31 is locked on the sample loading rotation seat 40 by a sample loading lock nut 43. An annular sample loading limit groove is formed at the lower part of the sample loading rotation seat. A sample loading limit rod 41 is provided on the sample loading adjustment seat 38. The upper part of the sample loading limit rod 41 is inserted into the sample loading limit groove, and the inserted part in the sample loading limit groove is arc-shaped and is tangentially coordinated with the sample loading limit groove.

[0035] The structure of this embodiment is mainly used for multi-point detection of the sample plate, that is, to adjust the position of the sample plate, and at the same time, it can cooperate with the water dripping structure to make seawater better adhere to the sample plate. When the sample plate 3 is placed into the sample loading device, first, the sample bracket 31 is installed at the lower part of the sample plate through bolts, and then the sample bracket 31 is penetrated by the loading screw 42. The sample bracket 31 is supported by the sample loading rotating seat 40, and then the sample bracket 31 is locked on the sample loading rotating seat 40 through the sample loading locking nut 43. After the installation of the sample plate 3 is completed, when dripping water, the sample loading rotating motor 39 drives the sample loading rotating seat 40 to rotate, so as to drive the sample plate 3 to rotate. The liquid dripping on the sample plate 3 will do centrifugal motion, so that all parts of the sample plate 3 can come into contact with the liquid, and the liquid escaping is thrown out under the centrifugal action, so it is more unlikely to enter the waterproof cover; after the laser detection of one point is completed, it is necessary to change to another point for laser detection. To this end, the position of the sample plate 3 needs to be adjusted. Specifically, the sample loading adjustment motor 34 drives the sample loading adjustment screw rod 35 to move, so as to drive the sample loading rotating motor 39 to move horizontally. Then, in combination with the rotation of the sample loading rotating motor 39 driving the sample loading rotating seat 40, all positions on the sample plate can be adjusted to the positions that match the pump laser and the detection laser, realizing the detection of the initial process of marine corrosion with multi-point seawater simulation.

[0036] When the sample loading rotating seat 40 rotates, the sample loading limit groove opened under it is limited by the sample loading limit rod 41, ensuring that its rotation trajectory is accurate and the rotation is stable without tilting, so as to ensure that the incident angles of the pump laser and the detection laser do not change.

[0037] It should be noted that in this article, the terms "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to this process, method, article or device.

[0038] In this article, specific examples are used to elaborate on the principle and implementation mode of the present invention. The description of the above examples is only used to help understand the method and its core idea of the present invention. The above is only the preferred implementation mode of the present invention. It should be pointed out that due to the limited nature of written expression and objectively existing infinite specific structures, for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements, refinements or changes can be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, should all be regarded as the protection scope of the present invention.

Claims

1. A detection method for the initial process of marine corrosion, characterized in that It includes the following steps: Step 1: Build three vacuum chambers and connect them with vacuum pipes to form a detection system for the initial process of marine corrosion. The minimum pressure of the vacuum chambers is 10-9 Torr. A sample mechanism for placing samples is provided in the third vacuum chamber, and a CCD detector is equipped; Step 2: Generate an ultrafast femtosecond laser with a repetition frequency of 1 kHz, a single-pulse energy of 6 mJ, a pulse width of 35 fs, and a central wavelength of 800 nm through a pulse amplifier; Step 3: Split the ultrafast femtosecond laser beam with a central wavelength of 800 nm and a pulse energy of 6 mJ. One beam of 2 mJ enters the vacuum chamber pipeline for transmission as the pulsed beam for detecting the initial process of ocean corrosion. The other beam of 4 mJ is transmitted outside the vacuum chamber as the pump pulse beam; the 800 nm, 2 mJ laser pulse entering the vacuum pipeline is focused into a gas chamber with a length of 40 cm filled with neon gas at a pressure of 75 Torr through a lens with a focal length of 70 cm, and interacts with the neon gas to generate high-order harmonics. The generated high-order harmonic wavelengths are in the XUV band, and the photon energy range is 36 - 72 eV, and then enters the first vacuum chamber for continuous transmission. The generated high-order harmonics in the XUV band are used as the detection beam of the detection system for the initial process of marine corrosion. The 4 mJ pump pulse beam transmitted outside the vacuum chamber is frequency-doubled through a BBO crystal to generate a pump pulse laser with a wavelength of 400 nm, and this wavelength can produce transition resonance with the metal to be detected; Step 4: Both the pump beam and the detection beam are incident on the sample of the sample mechanism in the third vacuum chamber, and then block the pump beam, and only let the detection beam be incident on the sample; Step 5: Use an aberration-corrected concave variable line-spacing grating to perform spectral dispersion on the XUV beam reflected from the sample and then enter the CCD detector. At the same time, collect the reflected pump beam to prevent any stray light from reaching the CCD detector; monitor the dynamic response of the sample after being excited by the pump light by measuring the changes in the transmittance, reflectance, or absorption of the sample surface.

2. The detection method of the primary process of marine corrosion according to claim 1, characterized in that, The time when the detection light passes through the target material is later than the time when the pump light reaches the target material.

3. The detection method of the primary process of marine corrosion according to claim 1, characterized in that The detection beam in the XUV band enters the second vacuum chamber from the first vacuum chamber, and the beam is focused on the sample surface of the third vacuum chamber through an annular mirror in the second vacuum chamber.

4. The detection method of the primary process of marine corrosion according to claim 3, characterized in that, The incident angle of the detection beam in the XUV band on the sample with respect to the surface normal is 82°, and the beam size (FWHM) on the sample is 1.01 ± 0.02 mm and 0.137 ± 0.002 mm on the tangential axis and sagittal axis respectively.

5. A detection method for the primary process of marine corrosion according to claim 4, characterized in that, The 400 nm pump beam is incident on the sample at an angle of 70° with respect to the sample surface normal, and the pump area is 2.43 mm 2 .

6. A detection method for the primary process of marine corrosion according to claims 1-5, characterized in that, After one detection is completed, the sample mechanism drives the sample on it to translate or rotate to change different detection points.

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