Testing device and method for three-electrode in-situ electrochemical hydrogen charging micro-nano mechanical test

Abstract

The invention discloses a three-electrode in-situ electrochemical hydrogen charging micro-nano mechanical test device and method, and belongs to the technical field of hydrogen energy. According to the device, overflow of hydrogen or generation of bubbles is prevented through a three-electrode system electrochemical in-situ hydrogen charging test method, and it is guaranteed that in the long-time testing process of hardness, a hydrogen diffusion coefficient, fatigue performance and the like, a sample is kept to be completely immersed in a hydrogen charging solution. According to the device, a sample placing table is connected with a container assembly, a sample is immersed in a hydrogen filling solution, and the sample is subjected to mechanical property characterization, hydrogen diffusion coefficient measurement and the like through a nanoindentation instrument. The method effectively solves the problem that in a traditional ex-situ hydrogen charging method, in the process from completion of hydrogen charging to start of a test, hydrogen in a material overflows, hydrogen bubbles are generated by in-situ hydrogen charging, and micro-nano mechanical testing is interfered. Bubbles generated during hydrogen charging can be effectively inhibited, so that the influence of the bubbles on a micro-nano mechanical test is solved.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen energy technology, specifically an experimental device and method for in-situ electrochemical hydrogen charging micro-nano mechanical testing using three electrodes. Background Technology

[0002] With the increasing depletion of fossil fuels, the development of new energy sources has become a global goal for scientists. Hydrogen energy offers advantages over other energy sources, including high efficiency, cleanliness, and abundant reserves. However, this also brings many challenges. For example, hydrogen is flammable and explosive, requiring extreme caution during storage and transportation. Furthermore, contact between hydrogen and metals can cause hydrogen embrittlement. Therefore, in the context of a hydrogen economy, high demands are placed on the hydrogen embrittlement resistance of metallic materials. Hydrogen embrittlement refers to the phenomenon where hydrogen atoms penetrate metallic materials, leading to a decrease in their toughness or load-bearing capacity, resulting in low-stress brittle fracture. This phenomenon, known as "metal plague," poses a serious threat to the safety of critical materials in aerospace, energy transportation, and chemical equipment industries.

[0003] To study the effects of hydrogen on metallic materials, it is necessary to perform a hydrogen-charging process on the metallic materials, then test their mechanical properties and observe their microstructure. Commonly used hydrogen-charging methods include aqueous solution electrolysis, gas-phase hydrogen charging, and molten salt electrolysis, among which aqueous solution electrolysis is the most widely used due to its advantages such as environmental friendliness and lower cost.

[0004] Most current research focuses on the macroscopic effects of hydrogen on metallic materials. However, with further research, the microscopic effects of hydrogen on metallic materials are becoming increasingly important, necessitating the use of precision instruments such as nanoindentation for this study.

[0005] Traditional hydrogen charging methods result in hydrogen gas escaping from the material after charging and before the start of the experiment, affecting the accuracy of the test. In-situ hydrogen charging, however, maintains a high hydrogen concentration in the metal material throughout, preventing gas escape. However, using in-situ hydrogen charging in nanoindentation testing requires consideration of the impact of hydrogen bubbles on the results. Therefore, suppressing bubble formation during the hydrogen charging process is crucial.

[0006] In summary, nanoindentation instruments can be used to study the microscopic effects of hydrogen on metallic materials. However, there is currently no experimental device that can perform nanoindentation tests while simultaneously charging with hydrogen, which poses a significant challenge to the study of the microscopic aspects. Summary of the Invention

[0007] This invention provides an in-situ constant potential electrochemical hydrogen-charged micro / nano mechanical testing device and method, which solves the problem that studying the effects of hydrogen on metallic materials is difficult in the microscopic field. It also effectively solves the problem that hydrogen combines into hydrogen gas and overflows, preventing long-term experiments. It can conduct long-term tests on metallic materials in a hydrogen environment, such as mechanical property testing, hydrogen diffusion coefficient testing, and fatigue testing, thereby further studying the effects of hydrogen on metallic materials at the microscale.

[0008] The present invention adopts the following technical solution: The experimental apparatus for in-situ electrochemical hydrogen-filled micro / nano mechanical testing using three electrodes, as described in this invention, consists of two parts: a container assembly and a sample placement stage. The container assembly provides a hydrogen environment, allowing hydrogen to fully penetrate the metal material. The container assembly is filled with a hydrogen-filling solution and includes a platinum wire electrode and a calomel reference electrode in contact with the hydrogen-filling solution. The platinum wire electrode and the calomel reference electrode are electrically connected to an electrochemical workstation, and the sample is electrically connected to the electrochemical workstation. The sample placement stage is used to place the sample, with connecting wires that contact the sample with a nano-indentation needle. The sample placement stage is a rectangular plate with a special arc-shaped notch design at the edges. Two circular holes are distributed on the plate surface for bolt connection to a boss in the container assembly. All parts of the apparatus are made of acrylic polymer material.

[0009] The experimental device for in-situ electrochemical hydrogen charging micro / nano mechanical testing of the three electrodes described in this invention includes a container assembly comprising a base and a cavity; the cavity is disposed on the base, with the horizontal end face of the base being larger than the end face of the cavity; a fixing screw hole is provided at the edge of the horizontal end face of the base; a boss for fixing the placement assembly is provided inside the cavity; and a left connection port and a right connection port for fixing the platinum wire electrode and the calomel reference electrode are provided on the side wall of the cavity.

[0010] The experimental device for in-situ electrochemical hydrogen charging micro / nano mechanical testing of the three electrodes described in this invention has a left connection port for fixing a platinum wire electrode, located at the center of the cavity sidewall; a right connection port for fixing a calomel reference electrode, located on the cavity sidewall on the other side of the left connection port, and the right connection port is close to the upper edge of the cavity sidewall; the calomel reference electrode is close to the sample of the sample placement assembly.

[0011] The experimental device for in-situ electrochemical hydrogen charging micro / nano mechanical testing of the three electrodes described in this invention includes a layout assembly comprising a layout stage and fixing bolts, wherein the shape of the layout stage matches that of the boss. The layout platform is equipped with a sample stage and is evenly distributed with screw holes two; the boss is equipped with screw hole one that matches the position of screw hole two on the layout platform; screw holes one and screw hole two between the layout platform and the boss are fixed to each other by bolts; the upper horizontal surface of the layout platform is used to place the sample.

[0012] The experimental device for in-situ electrochemical hydrogen charging micro-nano mechanical testing of the three electrodes described in this invention has a non-contact arrangement between the sample placement stage and the inner wall of the container assembly cavity; the combined height of the sample placement stage, sample, and boss is lower than the height of the top horizontal plane of the cavity.

[0013] The experimental device for in-situ electrochemical hydrogen charging micro / nano mechanical testing using three electrodes described in this invention employs silicone sealant between the left connection port and the platinum wire electrode, and silicone sealant between the right connection port and the calomel reference electrode.

[0014] The experimental method and steps for the three-electrode in-situ electrochemical hydrogen-charging micro / nano mechanical testing device are as follows: Step 1: Attach the sample with the welded wire to the placement table, and then connect the placement table with the sample attached to the boss inside the cavity through the screw hole and through hole using fastening bolts.

[0015] Step 2: Insert the platinum wire electrode and the calomel reference electrode into the connection ports on the left and right sides respectively, and then seal the two connection ports with silicone.

[0016] Step 3: Secure the device to the sample stage of the nanoindentation instrument using bolts through the four holes of the square base.

[0017] Step 4: Inject the hydrogen filling solution into the cavity using a syringe, with the liquid level 2 mm below the edge of the cavity.

[0018] Step 5: Connect the wires, platinum wire electrode, and calomel reference electrode welded to the sample to the electrochemical workstation, and turn on the electrochemical workstation according to the preset current density of the experiment. Step 6: Perform the test using the probe.

[0019] The test method of the three-electrode in-situ electrochemical hydrogen charging micro-nano mechanical testing device of the present invention includes an electrolyte in step 4 of the hydrogen charging solution.

[0020] The test method of the three-electrode in-situ electrochemical hydrogen-charging micro / nano mechanical testing device of the present invention, in step 5, the reference voltage of the saturated calomel reference electrode (9) is controlled at (E corr – 0.8) V ~ (E corr + 0.5) V, where E corr This is the corrosion potential.

[0021] Compared with the prior art, the significant advantages of this invention are: This invention has a simple structure and is easy to use. It can purge the sample with hydrogen while conducting the experiment, thereby increasing the accuracy and reliability of the experiment.

[0022] The present invention adopts a structure in which the sample laying stage and the cavity are separated, which facilitates the assembly and disassembly of the sample and the cleaning of the sample laying stage. The alternation of the two sample laying stages can make the test more convenient.

[0023] This invention is made of polymer materials, which are corrosion resistant, have a long service life, high transparency, and are easy to operate.

[0024] This invention ensures the real-time effect of hydrogen on materials through in-situ hydrogen filling, and with the positioning and mechanical property testing capabilities of the nanoindenter, it can effectively test the effect of hydrogen on metallic materials at the microscale, thereby achieving a quantitative assessment of the hydrogen embrittlement resistance of the microstructure of metallic materials.

[0025] This invention employs a three-electrode hydrogen charging method. In this three-electrode structure, the potentiostat directly monitors the true potential of the sample surface through the reference electrode. The current in the reference electrode branch is extremely small, which basically eliminates the voltage drop caused by the electrolyte resistance. Furthermore, when the local reaction becomes more intense, the three-electrode potentiostat will instantly fine-tune the output current of the platinum electrode based on the feedback from the reference electrode, which can completely suppress the generation of bubbles during hydrogen charging and eliminate the adverse effects of bubbles on the experiment. Attached Figure Description

[0026] Figure 1 This is a schematic diagram showing the assembled state of the present invention.

[0027] Figure 2 This is a schematic diagram of the container component of the present invention.

[0028] Figure 3 This is a schematic diagram of the lofting platform of the present invention.

[0029] Figure 4 This is a schematic diagram of a platinum wire electrode.

[0030] Figure 5 This is a schematic diagram of a calomel reference electrode.

[0031] Figure 6 This is a schematic diagram of the test sample.

[0032] Figure 7 Indentation load curve for Example 1 Figure 8 Example 2: CSM mode was used to obtain the change in hardness with indentation depth. Figure 9 Example 2: Nanoscale hardness difference between hydrogen-filled and non-hydrogen-filled samples Figure 10 Example 2: Peak hydrogen concentration Figure 11 Example 3: In-situ hydrogen-filled nanoindentation fatigue: Load-displacement curves of the indentation are shown below. The relationship between cycle time and maximum indentation depth Detailed Implementation

[0033] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] Combination Figures 1 to 6 A test apparatus for in-situ electrochemical hydrogen charging micro / nano mechanical testing using three electrodes, comprising a container assembly and a sample placement stage.

[0035] The container assembly provides a hydrogen-filled environment, ensuring full contact between sample 23 and hydrogen-filled liquid 5; the sample placement platform 7 is used to place and fix sample 3. Wires welded to sample 3, along with platinum wire electrode 6 and calomel reference electrode 9, are connected to electrochemical workstation 4 to achieve three-electrode hydrogen filling. The submersible pressure head 2, connected to converter 1, contacts the sample surface during operation to obtain the necessary experimental data.

[0036] The container assembly includes a cavity 13, a square base 10, a screw hole 11 on the base, a left connection port 12, a boss 14, a right connection port 15, and a screw hole 16 on the boss. The cavity 13 is disposed on the square base 10, and none of the four ends of the cavity 13 extend beyond the square base 10. The left connection port 12 and the right connection port 15 are located at the left and right ends of the cavity 13, respectively. The left connector 12 is used to insert the platinum wire electrode 6. During hydrogen charging, the platinum wire 17 must be completely immersed in the hydrogen charging solution 5. The right connector is used to insert the calomel reference electrode 9. During hydrogen charging, the wire connected to the sample 3, the platinum wire electrode 6, and the calomel reference electrode 9 work together. In this three-electrode structure, the potentiostat directly monitors the true potential of the sample surface through the reference electrode. The current in the reference electrode branch is extremely small, which basically eliminates the voltage drop caused by the electrolyte resistance. When the local reaction tends to be intense, the three-electrode potentiostat will instantly fine-tune the output current of the platinum electrode according to the feedback from the reference electrode, thereby suppressing the generation of hydrogen charging bubbles, thus obtaining a better hydrogen charging effect and a better working environment for the nanoindentation instrument.

[0037] The screw hole 11 on the base is used to fix the square base 10 to the sample stage of the nanoindentation instrument by screws; the screw hole 16 on the boss 14 and the screw hole 19 on the sample stage are connected to fix the sample stage 7 to the container assembly.

[0038] The sample placement stage 7 is not an integral part of the container assembly, but is connected via threads 8, which facilitates sample placement and cleaning of the sample placement stage 7. The shape and dimensions of the sample placement stage 7 are consistent with those of the boss 14, and it consists of screw holes 19 and a sample stage 19. The screw holes 19 and the screw holes 16 on the boss 14 are connected by screws to fix the sample placement stage to the boss 14; the diameter of the sample stage 18 is 2-3 mm larger than the diameter of the sample 3.

[0039] The container components and the lofting platform are all made of corrosion-resistant, highly transparent, and long-lasting polymer materials.

[0040] The experimental method and steps for the three-electrode in-situ electrochemical hydrogen-charging micro / nano mechanical testing device are as follows: Step 1: Apply correction fluid to the sample stage 18 of the sample placement table after welding the wires onto the sample 3. Then, connect the sample placement table 7 with the sample attached to it to the boss 14 inside the cavity 13 through the screw hole 19 and the through hole 16 using fastening bolts. The test material is a 20 mm diameter, 2 mm thick circular 316L material; the thread 8 is M6 type. Step 2: Insert the platinum wire electrode 6 and the calomel reference electrode 9 into the left connection port 12 and the right connection port 15 of the cavity 13, respectively, and then seal the two connection ports with silicone to prevent the hydrogen filling solution 5 in the cavity 13 from flowing out and damaging the test equipment; Step 3: Fix the device to the sample stage of the nanoindentation instrument using bolts through the four screw holes 11 of the square base 10; Step 4: Inject the hydrogen-filling solution 5 into the cavity 13 using a syringe, ensuring the liquid level is 2 mm below the edge of the cavity 13. This prevents the liquid level from overflowing and affecting the use of the testing equipment. Step 5: Connect the wires welded to sample 3, platinum wire electrode 6, and calomel reference electrode 9 to the electrochemical workstation 4, and turn on the electrochemical workstation according to the preset current density; control the reference voltage of the saturated calomel reference electrode 9 between -0.8 and 1V. SCE ; Step 6: Operate the submersible head 2 to conduct the test and record the test data.

[0041] Example 1: Nanoindentation hardness and elastic modulus tests were conducted in a hydrogen environment using two 316L stainless steel samples, one hydrogen-charged and the other uncharged. The samples underwent grinding and polishing treatments: grinding with sandpaper up to 2000#; mechanical polishing with 3.5 μm and 1.0 μm polishing pastes; and then electropolishing in a water bath. The hydrogen charging solution was a mixture of 0.5 mol / L sulfuric acid and 1 g / L thiourea. The test temperature was 26℃, and the current density was 10 mA / cm². 2 .

[0042] Step 1: Solder the wire to the sample 3, and glue the sample 3 to the sample stage 18 of the sample stage 7; use an M6 thread 8 to connect the sample stage 7 and the boss 14 through the screw hole 19 on the sample stage 7 and the through hole 16 on the boss 14; insert the platinum wire electrode 6 and the saturated calomel reference electrode 9 into the left connection port 12 and the right connection port 15 of the cavity 13 respectively, and seal the left connection port 12 and the right connection port 15 with silicone after insertion; Step 2: Secure the assembled device to the sample stage of the nanoindentation instrument using bolts through the four screw holes 11 of the square base 10; inject the hydrogen-filled solution 5 into the cavity 13 using a syringe, ensuring the liquid level is 2 mm below the edge of the cavity 13. Connect the wires, platinum wire electrode 6, and calomel reference electrode 9 welded to the sample 3 to the electrochemical workstation 4, and turn on the electrochemical workstation according to the preset current density; set the reference voltage of the saturated calomel reference electrode to -0.8 V. SCE ; Step 3: Operate the submersible indenter 2 to conduct the test. Measure the hardness and elastic modulus of the sample using the Oliver-Pharr method. Based on the load-displacement curve obtained from the test, calculate the elastic modulus from the slope of the initial portion of the unloading curve, and calculate the hardness value from the ratio of the maximum load to the contact projection area of ​​the indentation. Compare and analyze the data from hydrogen-filled and non-hydrogen-filled samples.

[0043] The indentation load curve of the test is as follows Figure 7 Based on this, the hardness and elastic modulus of the un-hydrogenated material were calculated to be 5 GPa and 188 GPa, respectively; the hardness and elastic modulus of the in-situ hydrogen-filled material were measured to be 3.7 GPa and 166 GPa, respectively. It is evident that hydrogen weakens the hardness and elastic modulus of the material, leading to metal embrittlement.

[0044] Example 2: The hydrogen diffusion coefficient in metallic materials was determined using nanoindentation experiments. The hydrogen diffusion coefficient was tested in two experiments: one sample was treated with hydrogen purging, and the other was not. The samples underwent grinding and polishing. The process involved grinding the samples with sandpaper up to 2000#; mechanical polishing was performed using 3.5 μm and 1.0 μm polishing pastes; and the mechanically polished samples were then subjected to water bath electrolytic polishing. The hydrogen purging solution was a mixture of 0.5 mol / L sulfuric acid and 1 g / L thiourea. The test temperature was 26℃, and the current density was 4 mA / cm². 2 Two different hydrogen charging times t c =100 min, after hydrogen charging, let stand for 45 min before nanoindentation testing. Nanoindentation peak load P max = 0.5~10 mN, strain rate is 0.0025 s -1 The spacing between the indentations is set to 100 micrometers; Step 1: Solder the wire to the sample 3, and use correction fluid to stick the sample 3 to the sample stage 18 of the sample stage 7; use an M6 thread 8 to connect the sample stage 7 and the boss 14 through the screw hole 19 on the sample stage 7 and the through hole 16 on the boss 14; insert the platinum wire electrode 6 and the saturated calomel reference electrode 9 into the left connection port 12 and the right connection port 15 of the cavity 13 respectively, and seal the left connection port 12 and the right connection port 15 with silicone after insertion; Step 2: Secure the assembled device to the sample stage of the nanoindentation instrument using bolts through the four screw holes 11 of the square base 10; inject the hydrogen-filled solution 5 into the cavity 13 using a syringe, ensuring the liquid level is 2 mm below the edge of the cavity 13. Connect the wires, platinum wire electrode 6, and calomel reference electrode 9 welded to the sample 3 to the electrochemical workstation 4, and turn on the electrochemical workstation according to the preset current density; set the reference voltage of the saturated calomel reference electrode to -0.8 V. SCE ; Step 3: Perform nanoindentation tests using a Berkovich indenter. Obtain the change in hardness with indentation depth using CSM mode. The results are as follows: Figure 8 The hydrogen diffusion coefficient was determined by analyzing the relationship between hydrogen-induced hardness changes and sample surface depth, combined with the hydrogen concentration distribution. Figure 9 The maximum value of hydrogen-induced hardness change is nm, converted to the peak position of hydrogen concentration distribution The hydrogen diffusion rate (nm) can be estimated from the peak hydrogen concentration. The location of the peak hydrogen concentration was calculated using Abaqus software, and the results are as follows: Figure 10 As shown, when the hydrogen diffusion rate is set to... m 2 / s hydrogen concentration peak position and The error is only 4.3%. This is consistent with the reported hydrogen diffusion rate of austenitic stainless steel (1~3) ≤ 10 in the literature. -16 m 2 / s verifies the reliability of this method.

[0045] Example 3: Fatigue test in hydrogen environment Fatigue tests in a hydrogen environment were conducted using nanoindentation. Two 316L stainless steel specimens were used as test materials; one was hydrogen-charged, and the other was not. The specimens underwent grinding and polishing treatments. The process involved grinding the specimens with sandpaper up to 2000#; mechanical polishing was performed using 3.5 μm and 1.0 μm polishing pastes; and the mechanically polished specimens were then subjected to water bath electrolytic polishing. The hydrogen charging solution was a mixture of 0.5 mol / L sulfuric acid and 1 g / L thiourea. The test temperature was 26℃, and the current density was 10 mA / cm². 2 Maximum load P max=50 mN, spacing set to 100 micrometers, number of cycles: 10 2 -10 5 Second-rate; Step 1: Solder the wire to the sample 3, and use correction fluid to stick the sample 3 to the sample stage 18 of the sample stage 7; use an M6 thread 8 to connect the sample stage 7 and the boss 14 through the screw hole 19 on the sample stage 7 and the through hole 16 on the boss 14; insert the platinum wire electrode 6 and the saturated calomel reference electrode 9 into the left connection port 12 and the right connection port 15 of the cavity 13 respectively, and seal the left connection port 12 and the right connection port 15 with silicone after insertion; Step 2: Secure the assembled device to the sample stage of the nanoindentation instrument using bolts through the four screw holes 11 of the square base 10; inject the hydrogen-filled solution 5 into the cavity 13 using a syringe, ensuring the liquid level is 2 mm below the edge of the cavity 13. Connect the wires, platinum wire electrode 6, and calomel reference electrode 9 welded to the sample 3 to the electrochemical workstation 4, and turn on the electrochemical workstation according to the preset current density; set the reference voltage of the saturated calomel reference electrode to -0.8 V. SCE ; Step 3: Perform nanoindentation tests using a Berkovich indenter. First, perform area function calibration and thermal drift correction (stabilizing to <0.05 nm / s). Then, perform a single indentation in the non-fatigue region to obtain the initial hardness H0 and elastic modulus E0. Set the triangular wave load waveform and record the load-displacement curve for each cycle. Monitor the residual depth h. res The changes in parameters such as energy dissipation with the number of cycles; the incremental residual depth This represents the displacement corresponding to the minimum load in each cycle, calculated using the following formula:

[0046] in Indicates the number of times the loop continues.

[0047] Energy dissipation This can be obtained by calculating the area enclosed by the Ph curve (the area of ​​the hysteresis loop):

[0048] in Indicates load, Indicates the depth of indentation. This can be understood as stopping the test when the tiny increment of work done by the indenter on the sample reaches a preset number of cycles or when there is a sudden change in displacement. Finally, the test data is collected and analyzed.

[0049] The results are as follows Figure 11 As shown, the maximum indentation depth gradually decreases as the cycle continues.

[0050] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An experimental setup for in-situ electrochemical hydrogen charging micro / nano mechanical testing using three electrodes, comprising an electrochemical workstation (4) and a nanoindentation instrument, characterized in that: The test apparatus includes a container assembly and a sample placement assembly; the container assembly is used to house the sample placement assembly and is filled with a hydrogen filling solution (5); the container assembly is provided with a platinum wire electrode (6) and a calomel reference electrode (9) that are in contact with the hydrogen filling solution (5). The placement assembly is used to place the sample (3). The platinum wire electrode (6) and the calomel reference electrode (9) are electrically connected to the electrochemical workstation (4), respectively. The sample (3) is electrically connected to the electrochemical workstation (4); The container assembly was tested on a nanoindentation instrument.

2. The experimental apparatus for in-situ electrochemical hydrogen charging micro / nano mechanical testing with three electrodes according to claim 1, characterized in that: The container assembly includes a base (10) and a cavity (13); A cavity (13) is provided on the base (10), and the horizontal end face of the base (10) is larger than the end face of the cavity (13); a fixing screw hole (11) is provided at the edge of the horizontal end face of the base (10). The cavity (13) is provided with a boss (14) for fixing the lofting assembly. The cavity (13) has a left connection port (12) and a right connection port (15) on its side wall for fixing the platinum wire electrode (6) and the calomel reference electrode (9).

3. The experimental apparatus for in-situ electrochemical hydrogen charging micro / nano mechanical testing with three electrodes according to claim 2, characterized in that: The left connection port (12) is used to fix the platinum wire electrode (6) and is located at the center of the side wall of the cavity (13); The right connection port (15) is used to fix the calomel reference electrode (9), and is located on the side wall of the cavity (13) on the other side of the left connection port (12), and the right connection port (15) is close to the upper edge of the side wall of the cavity (13); The calomel reference electrode (9) is close to the sample (3) of the sampling assembly.

4. The experimental apparatus for in-situ electrochemical hydrogen charging micro / nano mechanical testing with three electrodes according to claim 1 or 2, characterized in that, The lofting assembly includes a lofting table (7) and fixing bolts, wherein the shape of the lofting table (7) matches that of the boss (14); The laying-out table (7) is equipped with a sample table (18) and is evenly distributed with screw holes (19). The boss (14) is provided with a screw hole (16) that matches the position of the screw hole (19) of the lofting table (7); the screw hole (16) and the screw hole (19) between the lofting table (7) and the boss (14) are fixed to each other by bolts; The upper horizontal surface of the placement platform (7) is used to place the sample (3).

5. The experimental apparatus for in-situ electrochemical hydrogen charging micro / nano mechanical testing with three electrodes according to claim 4, characterized in that, The layout platform (7) and the inner wall of the cavity (13) of the container assembly are arranged in a non-contact manner; The combined height of the placement platform (7), the sample (3), and the boss (14) is lower than the height of the top horizontal plane of the cavity (13).

6. The experimental apparatus for in-situ electrochemical hydrogen charging micro / nano mechanical testing with three electrodes according to claim 3, characterized in that: The left connection port (12) and the platinum wire electrode (6) are sealed with silicone. The right connector (15) and the calomel reference electrode (9) are sealed with silicone.

7. A test method using the three-electrode in-situ electrochemical hydrogen charging micro / nano mechanical testing apparatus according to any one of claims 1 to 6, characterized in that, The steps are as follows: Step 1: Adhere the completed wire connection of the sample (3) to the laying platform (7) and fix the laying platform (7) to the boss (14) inside the cavity (13); Step 2: Platinum wire electrode (6) and calomel reference electrode (9) are respectively inserted into the left connection port (12) and right connection port (15) of the cavity (13), and the interface is sealed with silicone. Step 3: Install the cavity (13) onto the test platform of the nanoindentation instrument and fix it with the base (10); Step 4: Inject the electrolyte (5) into the cavity (13) while keeping the liquid level of the electrolyte (5) below the top horizontal plane of the cavity (13); Step 5: Set the test current density in the electrochemical workstation (4); Step 6: Operate the submersible indenter (2) of the nanoindentation instrument to test the sample (3) and record the test data.

8. The test method of the three-electrode in-situ electrochemical hydrogen charging micro / nano mechanical testing device according to claim 7, characterized in that, The hydrogen charging solution (5) in step 4 contains an electrolyte.

9. The test method of the three-electrode in-situ electrochemical hydrogen charging micro / nano mechanical testing device according to claim 7, characterized in that, In step 5, the reference voltage of the saturated calomel reference electrode (9) is controlled at E. corr – 0.8 V ~ E corr +0.5V, where E corr This represents the corrosion potential.

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