Hydrogen permeation and hydrogen micro-printing testing device and testing method

Abstract

The invention provides a hydrogen permeation and hydrogen micro-printing testing device. The hydrogen permeation and hydrogen micro-printing testing device comprises double electrolytic tanks and a rotary clamping mechanism, wherein the double electrolytic tanks comprise a hydrogen charging electrolytic tank and a hydrogen measuring electrolytic tank; openings are formed in the opposite sides of the hydrogen charging electrolytic tank and the hydrogen measuring electrolytic tank; the rotary clamping mechanism is arranged between the hydrogen charging electrolytic tank and the hydrogen measuring electrolytic tank, and two sides of a to-be-measured sample are respectively connected with openings of the hydrogen charging electrolytic tank and the hydrogen measuring electrolytic tank in a sealing manner; the hydrogen measuring electrolytic tank is provided with a dark coating, a developing agent injection opening is formed in the side, away from an opening of the hydrogen measuring electrolytic tank, of the hydrogen measuring electrolytic tank, and the position of the developing agent injection opening is opposite to the position of the opening in the hydrogen measuring electrolytic tank. Hydrogen permeation dynamic testing and hydrogen micro-printing developing detection are sequentially carried out on the same device, so that relevance characterization from macroscopic diffusion parameters to microcosmic hydrogen distribution is realized. The method solves the problems of macroscopic and microscopic data splitting and repeated sample preparation in the prior art, and is suitable for research on hydrogen trap characteristics and hydrogen embrittlement mechanisms of hydrogen sensitive materials such as high-strength steel.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen behavior characterization in metal materials, and particularly relates to a hydrogen permeation and hydrogen microprinting testing device and a testing method. BACKGROUND

[0002] With the wide application of hydrogen energy in the fields of energy and transportation, the hydrogen embrittlement failure mechanism of metal materials in a hydrogen environment has become a research hotspot. High-strength steel and other materials are prone to absorbing hydrogen atoms during service, leading to hydrogen embrittlement failure. The diffusion behavior of hydrogen in the material and the hydrogen trap distribution are the key to studying the hydrogen embrittlement mechanism and improving the hydrogen embrittlement resistance.

[0003] The existing hydrogen behavior characterization methods mainly include two types of macroscopic diffusion testing and microscopic visualization methods. Among them, the hydrogen permeation testing can quantitatively characterize the macroscopic kinetic parameters such as hydrogen diffusion coefficient and diffusible hydrogen concentration, but cannot reveal the specific enrichment of hydrogen at the micro defects (such as grain boundaries, precipitates, dislocations); and the hydrogen microprinting technology realizes the microscopic visualization of hydrogen distribution through the developing reaction, which can directly show the enrichment characteristics of hydrogen at the trap sites, but lacks the correlation with the macroscopic diffusion parameters, and it is difficult to quantify the hydrogen trapping ability of different traps.

[0004] However, due to the independence of the two types of characterization methods, the macroscopic diffusion behavior is disconnected with the microscopic distribution results, thereby affecting the accuracy and efficiency of hydrogen behavior characterization. SUMMARY

[0005] Therefore, the application provides a hydrogen permeation and hydrogen microprinting testing device and a testing method, which can realize the detection of hydrogen permeation and hydrogen microprinting developing in the same device, thereby improving the accuracy and efficiency of hydrogen behavior characterization.

[0006] In order to solve the above problems, the application provides a hydrogen permeation and hydrogen microprinting testing device, which comprises: a double electrolytic cell for hydrogen permeation testing of a to-be-tested sample; a rotating clamping mechanism for clamping and rotating the to-be-tested sample; The double electrolytic cell comprises a hydrogen charging electrolytic cell and a hydrogen testing electrolytic cell; the opposite sides of the hydrogen charging electrolytic cell and the hydrogen testing electrolytic cell are each provided with an opening; the rotating clamping mechanism is arranged between the hydrogen charging electrolytic cell and the hydrogen testing electrolytic cell, and the two sides of the to-be-tested sample are respectively sealedly connected with the openings of the hydrogen charging electrolytic cell and the hydrogen testing electrolytic cell; The hydrogen testing electrolytic cell has a dark color coating, and the side of the hydrogen testing electrolytic cell away from the opening thereof is provided with a developing agent injection port, and the position of the developing agent injection port is opposite to the position of the opening on the hydrogen electrolytic cell; After the hydrogen permeation testing of the to-be-tested sample, the to-be-tested sample is rotated by the rotating clamping mechanism, and the developing agent is injected through the developing agent injection port to perform hydrogen microprinting testing on the to-be-tested sample.

[0007] Further, the hydrogen permeation and hydrogen microprinting test device further comprises a galvanometer and an electrochemical workstation; The hydrogen charging electrolytic cell is connected to one pole of the galvanometer through a wire; the other pole of the galvanometer is connected to the sample to be tested through a wire; The platinum electrode in the hydrogen measurement electrolytic cell is connected to the first end of the electrochemical workstation through a wire; the reference electrode in the hydrogen measurement electrolytic cell is connected to the second end of the electrochemical workstation; and the third end of the electrochemical workstation is connected to the sample to be tested through a wire.

[0008] Further, the rotating clamping mechanism comprises a base, a connecting rod, a clamp and a locking screw; one end of the connecting rod is movably connected to the base and can rotate around the connecting point, and the other end is fixedly connected to the clamp; the clamp is used for clamping the sample to be tested; the locking screw is provided in at least two groups, one group penetrates through the threaded hole of the clamp and tightly presses the edge of the sample to be tested, and the other group is arranged at the connecting part of the connecting rod and the base and is used for locking the position of the connecting rod after the connecting rod drives the clamp and the sample to be tested to rotate to the target angle.

[0009] Further, the openings on the hydrogen charging electrolytic cell and the hydrogen measurement electrolytic cell are respectively connected to the sample to be tested through sealing O-shaped rubber rings.

[0010] Further, the developer injection port is sealed by a rubber plug.

[0011] Further, the hydrogen measurement electrolytic cell is a glass beaker with a dark coating.

[0012] Further, the glass beaker has a cover, and the cover is provided with a vent hole.

[0013] In another aspect, the present application provides a hydrogen permeation and hydrogen microprinting test method, which is realized by using the hydrogen permeation and hydrogen microprinting test device according to any one of the above aspects; and the method comprises the following steps: Assembly preparation: the metal sample to be tested is clamped and fixed between the hydrogen charging electrolytic cell and the hydrogen measurement electrolytic cell by the rotating clamping mechanism; Electrolytic hydrogen charging: electrolyte is injected into the hydrogen charging electrolytic cell, and a current is applied to the hydrogen charging side of the sample to be tested, so that hydrogen ions in the electrolyte are reduced to generate hydrogen atoms on the surface of the sample to be tested and permeate into the sample; Hydrogen permeation detection: electrolyte is injected into the hydrogen measurement electrolytic cell, and a constant anode potential is applied to the hydrogen measurement side of the sample to be tested; when the hydrogen atoms permeating into the sample diffuse to the surface of the hydrogen measurement side, they are oxidized to generate hydrogen ions under the anode potential, and the anode current signal generated by the oxidation reaction is collected in real time by the electrochemical workstation, so that the hydrogen permeation test is completed; Hydrogen micro-print detection: the sample to be tested is rotated by a rotating clamping mechanism, and a developing agent is injected through a developing agent injection port to cover the detection surface of the sample to be tested, so that the hydrogen atoms on the detection surface react with the developing agent to form micro-print traces (for example, Ag particles are formed when the developing agent is AgBr); then the micro-print trace image of the detection surface is obtained by a microscopic observation device (the distribution of Ag particles is observed by a scanning electron microscope), and the hydrogen micro-print test is completed.

[0014] Further, in the step of hydrogen permeation detection, a hydrogen permeation curve is obtained to determine the hydrogen saturation state of the sample to be tested; specifically, when the hydrogen permeation current density reaches a steady state platform and the slope of the hydrogen permeation curve tends to 0, it is determined that the sample is in a saturated hydrogen charging state; and when the current continues to rise and does not reach a steady state platform, it is determined that the sample is in an unsaturated hydrogen charging state.

[0015] Further, according to the hydrogen saturation state of the sample to be tested, the sample to be tested in the saturated hydrogen charging state is sequentially subjected to hydrogen permeation detection and hydrogen micro-print detection. Then, the parallel sample is replaced, electrolytic hydrogen charging is performed to make the sample reach an unsaturated hydrogen charging state, and the sample to be tested in the unsaturated hydrogen charging state is sequentially subjected to hydrogen permeation detection and hydrogen micro-print detection.

[0016] The hydrogen permeation and hydrogen micro-print testing device and testing method provided by the application have the following beneficial effects: (1) Cross-scale data correlation is achieved: for the first time, macroscopic hydrogen permeation testing and microscopic hydrogen micro-print detection are connected on the same device, effectively solving the problem of the disconnection of macroscopic diffusion parameters and microscopic hydrogen distribution data, and providing direct experimental basis for establishing the relationship between hydrogen diffusion-hydrogen trap enrichment-hydrogen embrittlement sensitivity.

[0017] (2) The accuracy and reliability of the data are improved: the data deviation caused by the microstructure difference between samples is avoided, the developing agent directly acts on the permeation area, and the consistency of the basis for data comparison is ensured, so that the conclusion is more reliable.

[0018] (3) The experimental efficiency is significantly improved and the cost is reduced: the function switching is realized by a rotating mechanism, without the need to replace parts, the process of twice independent sample preparation and testing is combined into one, the sample preparation time and material consumption are reduced, and the research efficiency is improved.

[0019] (4) The dynamic process of hydrogen trap behavior is revealed: by controlling the "saturated" and "unsaturated" hydrogen charging states, the hydrogen trapping priority and kinetic characteristics of different traps can be distinguished, which helps to understand the mechanism of hydrogen traps in the hydrogen charging process.

[0020] (5) Wide application range: The method is suitable for various metal materials, especially hydrogen embrittlement sensitive materials such as high-strength steel, and has wide application prospects in the fields of material research and development, quality evaluation and failure analysis. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. The drawings in the following description are only exemplary, and other embodiment drawings can be derived from the provided drawings without paying creative labor for those skilled in the art.

[0022] Figure 1 Schematic diagram of hydrogen permeation and hydrogen microprinting combined device for dual-function electrolytic cell reuse; Figure 2 Hydrogen permeation curve results of 0La under different hydrogen charging current densities; Figure 3 Hydrogen microprinting experimental results of 0La under 5mA / cm 2 2h of unsaturated hydrogen charging; Figure 4 Hydrogen microprinting experimental results of 0La under 5mA / cm 2 2h of saturated hydrogen charging; Figure 5 Hydrogen permeation curve results of 0La and 110La under 5mA / cm 2 Current density; Figure 6 Microstructure Ag particle distribution results of 0La and 110La under 5mA / cm 2 Current density; Figure 7 Ag particle distribution results around inclusions of 0La under 5mA / cm 2 Current density; Figure 8 Ag particle distribution results around inclusions of 110La under 5mA / cm 2 Current density; The drawings are as follows: 1-electrochemical workstation, 2-platinum electrode, 3-reference electrode, 4-vent hole, 5-cup cover, 6-rubber plug, 7-hydrogen measuring electrolytic cell, 8-set screw, 9-base, 10-current meter, 11-sample to be tested, 12-sealing O-ring, 13-clamp, 14-connecting rod. DETAILED DESCRIPTION

[0023] To further illustrate the technical means and effects taken by the present application to achieve the intended purpose, the specific implementation, structure, features, and effects according to the present application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0024] The hydrogen state has an important influence on the micro-distribution of hydrogen. In the unsaturated hydrogen charging state, hydrogen preferentially occupies part of the traps, which can be used to analyze the preferential capture sites of hydrogen. In the saturated hydrogen charging state, the hydrogen traps are fully filled, and the hydrogen distribution tends to be stable, which helps to evaluate the maximum hydrogen trapping capacity of different hydrogen traps. However, existing test systems can usually only perform single hydrogen permeation or hydrogen micro-printing experiments, and cannot achieve precise control of the hydrogen charging state and directly observe the corresponding micro-hydrogen distribution differences in the same device.

[0025] Traditional hydrogen micro-printing experiments can usually only qualitatively analyze the enrichment position of hydrogen atoms after hydrogen charging, while the hydrogen permeation-hydrogen micro-printing combined method proposed in the present application precisely determines the hydrogen penetration time and steady-state time through the hydrogen permeation curve, realizes the controllable differentiation of the unsaturated and saturated hydrogen charging states, and can systematically analyze the preferential release order of hydrogen in different traps and their maximum hydrogen trapping capacity.

[0026] In summary, the existing technology has information fragmentation between macroscopic diffusion and microscopic development, and lacks systematic characterization of the hydrogen distribution differences under different hydrogen charging states. Therefore, the development of a dual-electrolytic cell reuse system can realize the continuous detection of hydrogen permeation and hydrogen micro-printing development in the same device, and has the controllable function of distinguishing the hydrogen charging state (saturated / unsaturated), which is of great significance for accurately analyzing the hydrogen-induced failure mechanism and reducing experimental resource consumption.

[0027] Therefore, the present application proposes a combined method: the first experiment is saturated hydrogen charging and obtains the hydrogen permeation curve, at this time the hydrogen distribution tends to be stable, which can analyze the maximum hydrogen trapping capacity of different hydrogen traps. By analyzing the hydrogen permeation curve obtained in the first experiment, the hydrogen steady-state time (i.e. the time when the hydrogen traps are fully saturated, corresponding to the hydrogen permeation curve tending to be parallel to the horizontal axis) and the hydrogen penetration time (the time when hydrogen atoms first penetrate the sample and the through-current is detected on the anode side) can be determined. In the second hydrogen micro-printing experiment, the hydrogen charging time is selected to be greater than the hydrogen penetration time and less than the hydrogen steady-state time, and the unsaturated hydrogen charging is carried out, so that the preferential capture sites of hydrogen in different traps can be analyzed. The specific scheme is as follows: The present application provides a hydrogen permeation and hydrogen micro-printing test method, comprising the following steps: Step 1: Device preparation (1) Improved dual-electrolytic cell system: such as Figure 1As shown, including cathode chamber (hydrogen filling electrolytic cell, corresponding to the right side of the figure) and anode chamber (hydrogen measurement electrolytic cell 7, corresponding to the left side of the figure), the two chambers between the metal sample. Anode chamber is made of special dark coating glass to achieve light treatment and reduce hydrogen microprint development process interference by external light. The sample is fixed between the two chambers by a sealed O-ring and a clamp, ensuring gas-liquid isolation and exposing the sample to electrolyte on both sides. The cathode side is used for hydrogen production, and the anode side is used for detecting hydrogen permeation current.

[0028] (2) Rotating clamping mechanism: including clamp 13, connecting rod 14, bearing, locking screw 8 and base (iron stand) 9, for supporting and positioning double electrolytic cell. The module is rotatably connected through the bearing structure, and is self-locked by the locking screw. When the hydrogen microprint experiment is carried out, the rotating self-locking clamp module can rotate the double electrolytic cell along the horizontal axis by 90° and keep it in vertical position, so that the development operation can be carried out on the sample observation surface.

[0029] (3) Development solution injection module: the anode chamber side is provided with a liquid injection hole, which is sealed by a rubber plug during permeation experiment. In the state of rotating and standing the double electrolytic cell, the hydrogen microprint development solution can be directly added through the liquid injection hole, and the solution can uniformly cover the sample surface to carry out the development reaction.

[0030] The openings on the hydrogen filling electrolytic cell and the hydrogen measurement electrolytic cell are connected with the sample to be tested 11 through the sealed O-ring 12. The developer injection port (i.e. liquid injection hole) is sealed by the rubber plug 6. The hydrogen measurement electrolytic cell is a glass beaker with dark coating. Step 2: sample preparation Prepare a metallographic sample suitable for hydrogen permeation test device and hydrogen microprint observation, preferably with a size of 30×30×0.8mm. The front and back sides of the sample are polished to a mirror finish by 120#, 400#, 1000# and 2000# silicon carbide sandpaper and 1μm particle size diamond polishing paste, respectively, as the hydrogen filling surface (for simulating hydrogen intrusion environment) and the observation surface (for hydrogen microprint development observation).

[0031] Step 3: solution preparation Hydrogen permeation test solution: Cathode tank: 0.1~1mol / L NaOH+0.1~0.4 g / L CH4N2S alkaline solution, for electrolytic hydrogen atom production; preferably 0.1mol / L NaOH+0.22 g / L CH4N2S; Anode tank: 0.1~1mol / L NaOH electrolyte; Hydrogen microprint development solution AgBr nuclear emulsion: The present application provides a simple method for preparing AgBr nuclear emulsion development solution: (1) Gelatin particles were soaked in room temperature deionized water for 10-30 min (preferably 30 min) to fully absorb water and swell, then heated to 40-45℃, slowly stirred until completely dissolved, forming a transparent gelatin solution (concentration 5-10 wt%).

[0032] (2) Slowly add commercially available AgBr microcrystalline powder to the preheated gelatin solution (35-45℃, preferably 40℃), stir until evenly dispersed, then add 0.5-2.0 mol / L (preferably 1.4 mol / L) NaNO2 as an inhibitor.

[0033] Fixing solution: 0.1-1.0 mol / L Na2S2O3 + 0.5-2.0 mol / L NaNO2 (preferably 0.6 mol / L Na2S2O3 and 1.4 mol / L NaNO2) (volume ratio 1:1) Step 4: Hydrogen permeation test A modified double electrolytic cell device was used for hydrogen permeation experiments. The sample was the working electrode (WE), the thin platinum sheet electrode 2 was the counter electrode (CE), and the saturated calomel electrode with a salt bridge was the reference electrode 3 (RE). The cathode tank contained an alkaline solution composed of 0.1 M NaOH and 0.22 g / L CH4N2S. The cathode current was applied to generate hydrogen at the cathode by connecting the current meter 10. During the hydrogen charging process, hydrogen atoms were driven by the hydrogen concentration gradient to diffuse from the cathode side to the anode side along the thickness direction of the sample. The anode tank on the back side of the sample contained 0.1 M NaOH solution. A constant voltage (300 mV) was applied to ionize hydrogen atoms by the electrochemical workstation 1, and the raw data were recorded in real time to obtain the hydrogen permeation curve, and thus the hydrogen diffusion coefficient and other kinetic parameters were calculated.

[0034] Step 5: Hydrogen charging state control By adjusting the hydrogen charging time, two types of state samples were prepared: (1) Saturated hydrogen charging state: The first hydrogen permeation test was performed for a long time hydrogen charging treatment, such as 1-20 mA / cm 2 The current density was continuously charged for 2 h to fully saturate the hydrogen traps. By observing and processing the hydrogen permeation curve, the H penetration time (H atoms just penetrate the sample, showing the first appearance of hydrogen permeation current) and H steady state time (i.e. hydrogen saturation state, showing that the hydrogen permeation curve tends to be parallel to the x-axis) can be obtained.

[0035] (2) Unsaturated hydrogen charging state: The subsequent hydrogen permeation test refers to the H penetration time and steady state time of the first hydrogen permeation curve, and chooses a short time hydrogen charging such as 10 min, which makes the traps not fully filled.

[0036] Step 6: Device rotation and development processing The sample after hydrogen permeation test is cleaned with deionized water and alcohol and dried with cold air. After uniform corrosion of the observation surface with 4% nitric acid alcohol, the sample is cleaned again. The double electrolytic cell is vertically placed by rotating 90° along the horizontal axis through the rotary self-locking clamp module. After rotation, the original anode side faces upward. In a darkroom environment, the sample surface is directly dripped with AgBr core emulsion for 30 min. Then, the residual developer is removed by ultrasonic washing with 0.6 mol / L Na2S2O3 and 1.4 mol / L NaNO2 fixing solution for 5 min.

[0037] Step 7: Microscopic characterization and data analysis The distribution of Ag particles after development is observed by scanning electron microscopy (SEM), and the gray value and area distribution of Ag particles around different hydrogen trap sites are counted by image analysis software, thereby indirectly representing the distribution state of hydrogen in the material. The above results are associated with the macroscopic diffusion parameters in the hydrogen permeation curve, and the hydrogen trapping capacity of different trap types can be quantitatively characterized.

[0038] Further, in the step of hydrogen permeation detection, a hydrogen permeation curve is obtained to determine the hydrogen saturation state of the sample to be tested. Specifically, when the hydrogen permeation current density reaches a steady state platform and the slope of the hydrogen permeation curve tends to 0, it is determined that the sample is in a saturated hydrogen charging state. When the current continues to rise and does not reach a steady state platform, it is determined that the sample is in an unsaturated hydrogen charging state. First, the sample is saturated with hydrogen, and the sample to be tested in the saturated hydrogen charging state is subjected to hydrogen permeation detection and hydrogen microprinting in turn. Then, the parallel sample is replaced, and electrolytic hydrogen charging is performed to make the sample reach an unsaturated hydrogen charging state. The sample to be tested in the unsaturated hydrogen charging state is subjected to hydrogen permeation detection and hydrogen microprinting in turn.

[0039] Specifically, the sample to be tested in the saturated hydrogen charging state is subjected to hydrogen permeation detection and hydrogen microprinting in turn. After hydrogen microprinting, the hydrogen microprinting result is observed and analyzed by scanning electron microscopy (SEM). Subsequently, the second unsaturated hydrogen charging is performed on the replaced parallel sample. Since the time required for saturated hydrogen charging is usually longer, and the time range for unsaturated hydrogen charging can be flexibly selected, the appropriate hydrogen charging time can be selected according to the actual needs in the unsaturated hydrogen charging experiment. Subsequently, the sample in the unsaturated hydrogen charging state is subjected to hydrogen permeation detection and hydrogen microprinting in turn, and the hydrogen microprinting result is observed and analyzed by scanning electron microscopy (SEM).

[0040] The application will be further described below in conjunction with specific examples and comparative examples.

[0041] Example 1 This example provides a method for detecting hydrogen permeation and inclusion hydrogen distribution (hydrogen microprinting) of 42CrMo steel: (1) Sample preparation and surface treatment Several 30x30mm 42CrMo non-rare-earth steel 0La samples were prepared, and due to machining precision fluctuations, the thickness ranged from 0.6 to 0.8mm. The front and back sides of the sample were polished in turn with 120#, 400#, 1000#, and 2000# silicon carbide sandpaper and mechanically polished with 1μm particle size diamond polishing paste to a mirror finish.

[0042] (2) Hydrogen permeation solution preparation The cathode hydrogen charging solution was a mixture of 0.1M NaOH and 0.22g / L CH4N2S. 3g / 3g / 2g of NaOH solid powder and 0.44g of thiourea crystals were weighed three times using an electronic balance. In the first weighing, 3g of NaOH solid powder and 0.44g of thiourea crystals were poured into a beaker containing 500ml of deionized water, and stirred with a glass rod until the NaOH was completely dissolved, then poured into a 2L volumetric flask. In the second weighing, 3g of NaOH solid powder was poured into a beaker containing 500ml of deionized water, and stirred with a glass rod until the NaOH was completely dissolved, then poured into a 2L volumetric flask. In the third weighing, 2g of NaOH solid powder was poured into a beaker containing 500ml of deionized water, and stirred with a glass rod until the NaOH was completely dissolved, then poured into a 2L volumetric flask. In the fourth weighing, 500ml of deionized water was poured into the 2L volumetric flask to make up the volume.

[0043] The anode electrolyte was 0.1M NaOH. 3g / 3g / 2g of NaOH solid powder was weighed three times using the same preparation method as above and poured into 500ml of deionized water to prepare 2L of 0.1M NaOH.

[0044] (3) Hydrogen microprinting solution preparation Developing solution AgBr nuclear emulsion: 1g of gelatin particles were soaked in 20ml of deionized water at room temperature for 30min to fully absorb water and swell, then heated to 40-45℃, slowly stirred until completely dissolved, forming a transparent gel solution (concentration 5-10wt%). Slowly add 1g of AgBr microcrystalline powder to the preheated gelatin solution (40℃), stir until evenly dispersed, then add 5ml of 1.4mol / L NaNO2 as an inhibitor.

[0045] Fixing solution: 20ml of 0.6mol / L Na2S2O3 and 20ml of 1.4mol / L NaNO2 (volume ratio 1:1) (4) Hydrogen permeation test and hydrogen charging state control Saturated and non-saturated hydrogen charging states were provided for hydrogen microprinting detection by adjusting the hydrogen charging time. Hydrogen permeation tests were carried out in a modified double electrolytic cell. First, the hydrogen charging current density was controlled at 5 mA / cm2 for 2 h, and data acquisition was carried out by CHI760 electrochemical workstation. A constant voltage of 300 mv was applied, and the hydrogen permeation curve was recorded in real time. Before each test, the background current density in the anode cell needs to be reduced to a stable level below 1 μA / cm 2 , and this background current should be subtracted from the measured permeation current in subsequent data analysis.

[0046] (5) Saturated hydrogen charging hydrogen microprinting development process The sample in the device was charged with a current density of 5 mA / cm 2 for 2 h, and then the rotating electrolytic cell was placed vertically at 90°. In a dark room environment, the development solution was added to the sample observation surface through the liquid injection module. After 30 min of development, the sample was taken out and placed in the fixing solution for ultrasonic washing for 5 min to remove the residual developer.

[0047] (6) Non-saturated hydrogen charging hydrogen microprinting development process Referring to the hydrogen permeation curve under the saturated hydrogen charging state, the 0La penetration time is about 520 s, and the steady-state time is about 1.5 h. This indicates that the hydrogen traps of the 0La sample are completely saturated after 2 h of hydrogen charging, while the hydrogen traps are not completely filled when the hydrogen charging time is 10 min. Therefore, the hydrogen charging current density was controlled at 5 mA / cm 2 for 10 min, and after the hydrogen charging was completed, the development solution was added to the sample observation surface through the top liquid injection module in a dark room environment. After 30 min of development, the sample was taken out and placed in the fixing solution for ultrasonic washing for 5 min to remove the residual developer.

[0048] (7) Microscopic characterization and data analysis The distribution of Ag particles around the inclusions after development was observed using a scanning electron microscope (SEM), and the results were correlated with the macroscopic diffusion parameters in the hydrogen permeation curve.

[0049] Example 2 42CrMo rare earth steel and non-rare earth steel hydrogen permeation and microstructure hydrogen distribution detection method: (1) Sample preparation and surface treatment 30×30 mm 42CrMo non-rare earth steel 0La and rare earth steel 110La samples were prepared. Due to the fluctuation of machining precision, the thickness ranged from 0.6 to 0.8 mm. The front and back sides of the sample were polished to a mirror finish by 120#, 400#, 1000#, and 2000# silicon carbide sandpaper and then mechanically polished with 1 μm particle size diamond polishing paste.

[0050] (2) Hydrogen permeation solution preparation Catholyte solution is a mixture of 0.1 M NaOH and 0.22 g / L CH4N2S. 3g / 3g / 2g NaOH solid powder and 0.44g thiourea crystal were weighed by electronic balance for three times, 3g NaOH solid powder and 0.44g thiourea crystal were poured into a beaker containing 500ml deionized water, stirred with a glass rod until the NaOH was completely dissolved, and then poured into a 2L volumetric flask. The second time, 3g NaOH solid powder was poured into a beaker containing 500ml deionized water, stirred with a glass rod until the NaOH was completely dissolved, and then poured into a 2L volumetric flask. The third time, 2g NaOH solid powder was poured into a beaker containing 500ml deionized water, stirred with a glass rod until the NaOH was completely dissolved, and then poured into a 2L volumetric flask. The fourth time, 500ml deionized water was poured into a 2L volumetric flask to constant volume.

[0051] Anolyte solution is 0.1 M NaOH. 3g / 3g / 2g NaOH solid powder was weighed by the same preparation method as above and poured into 500ml deionized water to prepare 2L 0.1 M NaOH.

[0052] (3) Hydrogen microprint solution preparation Developing solution AgBr core emulsion: 1g gelatin particles were soaked in 20ml deionized water at room temperature for 30min to fully absorb water and swell, then heated to 40-45℃, slowly stirred until completely dissolved, forming a transparent gel solution (concentration 5-10wt%). Slowly add 1g AgBr microcrystalline powder on the market in the preheated gelatin solution (40℃), stir until evenly dispersed, then add 5ml 1.4mol / L NaNO2 as inhibitor.

[0053] Fixing solution: 20ml 0.6mol / L Na2S2O3 and 20ml 1.4mol / L NaNO2 (volume ratio 1:1) (4) Hydrogen permeation test Hydrogen permeation test was carried out in a modified double electrolytic cell, CHI760 electrochemical workstation was used for data acquisition, constant voltage 300mv was applied and hydrogen permeation curve was recorded in real time. Before starting the test, the background current density in the anode cell needs to be reduced to a stable level below 1μA / cm 2 , which should be subtracted from the measured permeation current in subsequent data analysis.

[0054] (5) Hydrogen microprint developing treatment After hydrogen permeation test, the sample was rinsed clean and air-dried, and then the observation surface was etched with 4% nitric acid alcohol and rinsed clean again. The rotating electrolytic cell was placed vertically 90°, and then the developing solution was added on the observation surface of the sample through the liquid injection module in a dark room environment. After 30 min of development, the sample was taken out and transferred into the fixing solution for ultrasonic rinsing for 5 min to remove the residual developing agent.

[0055] (6) Microscopic characterization and data analysis The distribution of Ag particles in the microstructure after development was observed using a scanning electron microscope (SEM), and the above results were correlated with the macroscopic diffusion parameters in the hydrogen permeation curve to quantitatively characterize the hydrogen trapping ability of different hydrogen traps.

[0056] As can be seen from Figure 2 , the 5mA / cm 2 The 0La breakthrough time under the hydrogen charging current density was about 520s, and the steady-state time was about 1.5h. Corresponding, it can be determined that the hydrogen charging for 10min is in the unsaturated hydrogen charging state, and the hydrogen charging for 2h is in the saturated hydrogen charging state.

[0057] As can be seen from Figure 3 , under the unsaturated hydrogen charging state of 10min, Ag particles were only deposited near the MnS / matrix interface, and no Ag particle enrichment was observed around the Al2O3 / matrix interface. For MnS-Al2O3 composite inclusions, Ag particles preferentially gathered on the side of the MnS component, and almost no Ag particles were deposited around the Al2O3 component. This means that the reduction reaction of Ag ions preferentially occurs near the MnS / matrix interface, indicating that the hydrogen trapping priority of MnS is higher than that of Al2O3.

[0058] As can be seen from Figure 4 , under the saturated hydrogen charging state of 2h, Ag particles can be detected at the interfaces of MnS and Al2O3. The Ag particle accumulation area of MnS is larger than that of Al2O3, which indicates that the hydrogen trapping ability of MnS may be higher than that of Al2O3.

[0059] As can be seen from Figure 5 , the hydrogen permeation curve of rare earth steel 110La is overall lagged and right-shifted compared to that of non-rare earth steel 0La, indicating that the hydrogen diffusion coefficient of rare earth steel 110La is smaller, and the diffusion of hydrogen atoms in rare earth steel is more hindered.

[0060] As can be seen from Figure 6 , in 42CrMo steel, H atoms are prone to accumulate in hydrogen trap sites such as prior austenite grain boundaries, martensite lath boundaries and inclusions As can be seen from Figure 7 and 8It can be seen that the comparison of Ag particle distribution at the inclusion / matrix interface for both 0La and 110La shows that the rare earth inclusions strongly attract the surrounding hydrogen atoms, forming a "hydrogen depleted zone". The hydrogen trapping ability of the inclusions is largely related to the size. Only large size MnS (>15 pm) shows significant silver particle enrichment at the MnS / matrix interface and can produce a similar "hydrogen depleted zone" effect, while small size MnS-Al2O3 usually only shows silver particle enrichment at local tips. In contrast, the rare earth inclusions (≤2 pm) are uniformly surrounded by silver particles, which indicates that, within the same micron size range, the rare earth inclusions are superior to MnS and Al2O3 in terms of hydrogen trapping ability.

[0061] Those skilled in the art will readily understand that the advantageous technical features of the above-mentioned modes can be freely combined, superimposed, without conflict.

[0062] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A hydrogen permeation and hydrogen microprinting test apparatus characterized by comprising: The application relates to a hydrogen permeation and hydrogen microprinting testing device. The device comprises a double electrolytic cell for hydrogen permeation testing of a sample to be tested; and a rotating clamping mechanism for clamping and rotating the sample to be tested. The double electrolytic cell comprises a hydrogen charging electrolytic cell and a hydrogen testing electrolytic cell; the hydrogen charging electrolytic cell and the hydrogen testing electrolytic cell are provided with openings on opposite sides; the rotating clamping mechanism is arranged between the hydrogen charging electrolytic cell and the hydrogen testing electrolytic cell, and the two sides of the sample to be tested are respectively sealedly connected with the openings of the hydrogen charging electrolytic cell and the hydrogen testing electrolytic cell. The hydrogen testing electrolytic cell is provided with a dark coating, and a developer injection port is arranged on the side of the hydrogen testing electrolytic cell away from the opening, and the position of the developer injection port is opposite to the position of the opening of the hydrogen electrolytic cell. After the hydrogen permeation testing of the sample to be tested, the sample to be tested is rotated by the rotating clamping mechanism, and a developer is injected through the developer injection port to perform hydrogen microprinting testing on the sample to be tested. The hydrogen permeation and hydrogen microprinting testing device further comprises a galvanometer and an electrochemical workstation.

2. The hydrogen permeation and hydrogen microprint testing device according to claim 1, characterized in that, The hydrogen charging electrolytic cell is connected with one pole of the galvanometer through a wire; and the other pole of the galvanometer is connected with the sample to be tested through a wire. The platinum electrode in the hydrogen testing electrolytic cell is connected with the first end of the electrochemical workstation through a wire; the reference electrode in the hydrogen testing electrolytic cell is connected with the second end of the electrochemical workstation; and the third end of the electrochemical workstation is connected with the sample to be tested through a wire. The rotating clamping mechanism comprises a base, a connecting rod, a clamp and a locking screw; one end of the connecting rod is movably connected with the base and can rotate around the connecting point, and the other end is fixedly connected with the clamp; the clamp is used for clamping the sample to be tested; and the locking screw is arranged in at least two groups, one group penetrates through the threaded hole of the clamp and tightly presses the edge of the sample to be tested, and the other group is arranged at the connecting position of the connecting rod and the base and is used for locking the position of the connecting rod after the connecting rod drives the clamp and the sample to be tested to rotate to a target angle.

3. The hydrogen permeation and hydrogen microprint testing device according to claim 1, characterized by The openings on the hydrogen charging electrolytic cell and the hydrogen testing electrolytic cell are respectively connected with the sample to be tested through sealing O-shaped rubber rings.

4. The hydrogen permeation and hydrogen microprint testing device according to claim 1, characterized by The developer injection port is sealed through a rubber plug.

5. The hydrogen permeation and hydrogen microprint testing device according to claim 1, characterized by The hydrogen testing electrolytic cell is a glass beaker with a dark coating.

6. The hydrogen permeation and hydrogen microprint testing device according to claim 1, characterized by The glass beaker is provided with a cup cover, and the cup cover is provided with a vent hole.

7. The hydrogen permeation and hydrogen microprint testing device according to claim 1, characterized by The hydrogen permeation and hydrogen microprinting testing method is realized by using the hydrogen permeation and hydrogen microprinting testing device according to any one of claims 1 to 7; and the method comprises the following steps:

8. A hydrogen permeation and hydrogen microprint testing method characterized by, Assembly preparation: the metal sample to be tested is clamped and fixed between the hydrogen charging electrolytic cell and the hydrogen testing electrolytic cell through the rotating clamping mechanism; Electrolytic hydrogen charging: electrolyte is injected into the hydrogen charging electrolytic cell, and a current is applied to the hydrogen charging side of the sample to be tested, so that hydrogen ions in the electrolyte are reduced to hydrogen atoms on the surface of the sample to be tested and permeate into the sample; Hydrogen permeation detection: electrolyte is injected into the hydrogen testing electrolytic cell, and a constant anode potential is applied to the hydrogen testing side of the sample to be tested; when the hydrogen atoms permeating into the sample diffuse to the surface of the hydrogen testing side, the hydrogen atoms are oxidized to hydrogen ions under the anode potential, and an anode current signal generated by the oxidation reaction is collected in real time through the electrochemical workstation, so that the hydrogen permeation testing is completed; ​ Hydrogen micro-print detection: the sample to be tested is rotated by a rotating clamping mechanism, and a developing agent is injected through a developing agent injection port to cover the detection surface of the sample to be tested, so that hydrogen atoms on the detection surface react with the developing agent to form micro-print traces on the detection surface; then, a micro-print trace image of the detection surface is obtained by a microscopic observation device to complete the hydrogen micro-print test.

9. The hydrogen permeation and hydrogen microprint testing method according to claim 8, characterized in that, In the hydrogen permeation detection step, a hydrogen permeation curve is obtained to determine the hydrogen saturation state of the sample to be tested.

10. The hydrogen permeation and hydrogen microprint testing method according to claim 9, characterized by, According to the hydrogen saturation state of the sample to be tested, the sample to be tested in the saturated hydrogen state is sequentially subjected to hydrogen permeation detection and hydrogen micro-print detection. Then, the parallel sample is replaced, and the sample to be tested in the unsaturated hydrogen state is sequentially subjected to hydrogen permeation detection and hydrogen micro-print detection.

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