A device and method for automatically testing the hydrogen evolution rate of magnesium-based metal materials

Abstract

The present invention discloses a device and method for automatically testing the hydrogen evolution rate of magnesium-based metal materials. The device comprises an experimental tank, a hydrogen collector, an electric lifter, a liquid storage tank, a thermostat, a temperature and humidity sensor, a control mainboard, and a visual control system. First, the solution required for the test and the sample to be tested are respectively injected into the liquid storage tank and fixed in the sample rack, and then the experimental parameters are set in the visual control system. When the parameters in the device reach the set values, the device automatically starts, and the liquid in the liquid storage tank is injected into the experimental tank and reaches the default liquid level. The operation control system controls the electric lifter and the measuring instrument to operate in coordination to realize the automatic and continuous measurement of the hydrogen volume. The visual control system will display the test results such as the hydrogen volume and the hydrogen evolution rate in real time. The present invention can test the hydrogen evolution rate of magnesium-based metal materials for a long time, efficiently and stably, and can avoid the influence of ambient temperature on the gas volume and corrosion rate, thereby improving the accuracy of the test results.

Description

Technical Field

[0001] The invention belongs to the field of corrosion, and in particular relates to an automatic hydrogen evolution corrosion rate testing device and method, which is particularly suitable for hydrogen evolution rate testing of magnesium and its alloys and magnesium-based composite materials. Background Art

[0002] With the increasing prominence of energy issues and the increasing demand for "lightweight" in the automotive, aerospace and other fields, magnesium alloy, as the lightest structural material, is one of the ideal lightweight materials. Magnesium alloy is rich in resources, high in specific strength, environmentally friendly, and has good damping performance, electromagnetic shielding performance, biocompatibility and other characteristics. As a structural material, magnesium alloy has been partially applied in the fields of automobiles, 3C products, aerospace, energy industry and biomedical materials. The development and application of magnesium alloys will be conducive to the lightweighting of China's manufacturing, greatly promote energy conservation and emission reduction, and promote the realization of the "dual carbon" goals.

[0003] Since the electrode potential of magnesium alloy is extremely negative and the PB ratio is less than 1, the corrosion resistance of magnesium alloy is poor. The poor corrosion resistance of magnesium alloy is one of the main reasons restricting the large-scale application of magnesium alloy. The development of new corrosion-resistant magnesium alloy is a hot topic in the research of magnesium alloy today. The corrosion rate is an important indicator for evaluating the corrosion resistance of magnesium alloy. In order to achieve large-scale application of magnesium alloy, it is inevitable to use the corrosion rate under the working condition as the basis for use. Therefore, a convenient magnesium alloy corrosion rate test device is essential.

[0004] In the field of magnesium alloy corrosion research, the main methods for determining the corrosion rate of magnesium alloys are electrochemical method, weight loss method and hydrogen evolution method. The weight loss method is the mass loss of the metal before and after corrosion divided by the corrosion area and corrosion time. This method is recognized as the most reliable corrosion rate determination method in the field of metal materials. However, this method usually has a large amount of experiments, the experimental process is relatively cumbersome, and the obtained corrosion rate is the average corrosion rate of the corrosion process, which cannot reflect the change in corrosion rate. Due to the "negative difference effect" of magnesium, the test results of the electrochemical method are quite different from the actual value, and can only be used as a qualitative analysis method.

[0005] Magnesium is highly active, and its corrosion is actually a process of reacting with water to generate hydrogen:

[0006] Mg+2H2O=Mg(OH)2↓+H2↑

[0007] The hydrogen evolution method is used to determine the corrosion rate of magnesium. The hydrogen generated during the corrosion process is collected, and the hydrogen evolution rate represents the corrosion rate of magnesium, or the mass loss of magnesium is calculated based on the collected hydrogen volume, thereby converting it into a weight loss corrosion rate.

[0008] At present, the device for determining the corrosion rate of magnesium and its alloys according to the hydrogen evolution method is composed of an inverted funnel and a burette, such as a special experimental device for determining the corrosion rate of magnesium or magnesium alloys disclosed in Chinese patent CN102564932A. The device has a simple structure, low cost and is easy to use. However, there are also some shortcomings: (1) The collected hydrogen evolution volume needs to be recorded regularly by the experimenter, which is time-consuming and labor-intensive. (2) The volume of the burette is limited, and it needs to be manually replaced in time after exceeding the range, so the experimenter needs to supervise the whole process. (3) During long-term testing, it is inconvenient to record data at night. (4) The effect of temperature on the gas molar volume Vm is not considered. When calculating the weight loss rate converted from the hydrogen evolution rate, the calculation formula uses the gas molar volume of 22.4L / mol under standard conditions (0°C, 101.33kPa). According to the ideal gas equation PV = nRT, Vm = V / n = (RT) / P, under standard atmospheric pressure, the gas molar volume is proportional to the ambient temperature; when the experimental ambient temperature is 50°C, the gas molar volume is 26.5L / mol. Therefore, the experimental temperature change causes a large error in the corrosion rate test results. Therefore, when calculating the weight loss corrosion rate converted from the hydrogen evolution rate, it is necessary to consider the effect of temperature on the gas volume to make the calculation result more accurate, and the gas molar volume under standard conditions cannot be simply used. Summary of the invention

[0009] In order to solve the problems described in the background, the present invention provides an automated test device and method for hydrogen evolution rate of magnesium, magnesium alloys and magnesium-based composite materials. The device can automatically obtain experimental results in real time under a controllable environment. The specific technical solution is as follows:

[0010] A device for automatically testing the hydrogen evolution rate of magnesium-based metal materials, the device consists of four parts: an experimental cabin, an auxiliary cabin, an operation control cabin and a visual control system. The experimental cabin includes an experimental tank, one side of which is provided with a full-automatic liquid level control valve, and the bottom of the tank is provided with a plurality of sample racks for fixing the tested samples, the samples are magnesium-based metal materials; a hydrogen collector array is provided directly above the samples; the hydrogen collector is fixed on a tray; a temperature sensor and a humidity sensor are also provided in the experimental cabin; the auxiliary cabin includes a constant temperature and humidity controller and a liquid storage barrel, the liquid storage barrel is provided with a heating rod, and is connected to the experimental tank through a conduit; the operation control cabin includes a control mainboard and an electric lifter array, the electric lifter is composed of a servo motor and a retractable lifting rod, and the front end of the lifting rod is connected to the tray; the visual control system can control the coordinated operation of various parts of the device according to the set experimental parameters, and process and visualize the acquired data in real time.

[0011] Furthermore, the magnesium-based metal material includes magnesium, magnesium alloy and magnesium-based composite material.

[0012] Furthermore, a fully automatic liquid level control valve arranged on one side of the experimental tank can automatically open the valve when the liquid level in the experimental tank is lower than a set value, so that the solution is injected from the storage tank into the experimental tank through the catheter, and the valve is closed after the liquid level returns to the set height.

[0013] Furthermore, the hydrogen collector is composed of a laser rangefinder, an electromagnetic valve and a gas collecting bottle; the laser rangefinder data collection time interval can be adjusted in the range of 1 to 360 min / time, and is used to regularly measure the change in liquid level height in the gas collecting bottle caused by collecting hydrogen; the electromagnetic valve is used to control the connection and disconnection between the gas collecting bottle and the outside world; the effective volume of the gas collecting bottle is the volume between the highest liquid level scale line and the lowest liquid level scale line of the gas collecting bottle; three hydrogen collectors are grouped together, and three parallel samples are tested simultaneously to obtain the average value as the final result; there is no less than one group of hydrogen collectors, and it can be increased according to test requirements.

[0014] Furthermore, the electric lifters are arranged at both ends of the tray, and the electric lifters at both ends are linked to drive a group of hydrogen collectors to move up and down; the electric lifters are set with three gears: standby gear, working gear and liquid level reset gear, and the functions are to lift the hydrogen collector to the highest point to facilitate taking out the experimental tank for cleaning, half-immerse the hydrogen collector in the solution to facilitate collecting hydrogen, immerse the hydrogen collector in the solution of the experimental tank and open the solenoid valve to restore the liquid level in the gas collecting bottle to the highest liquid level scale line.

[0015] Furthermore, the thermostat and hygrostat have adjustment ranges of 0 to 80°C and 0 to 99% RH for the temperature and humidity in the experimental chamber respectively; the heating rod can heat the reagents in the liquid storage tank in the range of 0 to 80°C; when the temperature and humidity values ​​are set to -1 in the visual control system, the thermostat and hygrostat and the heating rods in the liquid storage tank do not work, and the actual ambient temperature experiment is adopted.

[0016] Furthermore, the control main board is a data collection and operation command transmission module, which is connected to the hydrogen collector, temperature and humidity sensor, constant temperature and humidity controller, heating rod and electric lifter through wires. It can obtain the measurement data of each part in real time, control the coordinated operation of each part, and transmit the measurement data to the visual control system.

[0017] Furthermore, the visual control system can issue operating instructions according to the set experimental parameters to control the coordinated operation of various parts of the entire device, and perform real-time processing and data visualization of the acquired data;

[0018] Data processing calculation formula:

[0019] V t =mV max +πr 2 (h0-h t ) (1)

[0020]

[0021] According to the ideal gas equation: PV = nRT

[0022]

[0023]

[0024] In formula (1): V t is the volume of hydrogen at test time t (ml), m is the number of liquid level resets, V max is the effective volume of the hydrogen collector (ml), r is the inner radius of the gas collecting bottle (mm), h0 is the initial liquid level (mm), h t is the liquid level height at test time t (mm);

[0025] In formula (2): P H is the hydrogen evolution rate at test time t (ml·cm -2 ·h -1 ), V H is the volume of hydrogen evolution per unit area at time t (ml·cm -2 ), t is the test time (h);

[0026] In formula (3): P w is the hydrogen evolution rate expressed by weight loss method (g·cm -2 ·h -1 ), T is the set experimental temperature (K);

[0027] In formula (4): P d is the hydrogen evolution rate expressed by the depth method (mm·y -1 ), ρ is the density of the material being measured (g·cm -3 );

[0028] The hydrogen evolution volume V can be obtained by the above formula t , hydrogen evolution rate P H , weight loss corrosion rate P w And the depth method corrosion rate P d The relationship data with the corresponding test time is then plotted to draw a visual curve graph.

[0029] A method for using the device for automatically testing the hydrogen evolution rate of magnesium-based metal materials as described above, the method specifically comprises the following steps:

[0030] (1) First, prepare the required solution and inject it into the liquid storage tank, prepare the samples to be tested, and each group of samples has 3 parallel samples. After measuring the exposed area of ​​the samples, fix the samples to be tested on the sample holder;

[0031] (2) Open the visual control system, set the experimental chamber working temperature, humidity, storage tank solution heating temperature, test time interval, total test time and material density and other parameters, and then click the start button to start the equipment. At this time, the constant temperature and humidity controller and the heating rod start working, and the temperature sensor and humidity sensor monitor the temperature and humidity in the experimental chamber in real time;

[0032] (3) After the temperature and humidity parameters reach the set value (if the parameter is set to -1, there is no need to wait), the automatic liquid level control valve opens, and the solution is injected from the storage tank into the experimental tank. After reaching the set height, the automatic liquid level control valve automatically closes. During the experiment, if the solution is lower than the set height, it can also be automatically replenished;

[0033] (4) The electric lifter is started, and the telescopic rod is extended to drive the hydrogen collector down to the liquid level reset position. At this time, the solenoid valve is opened to allow the solution to fill the gas collecting bottle. When the liquid level in the gas collecting bottle returns to the highest liquid level scale line, the solenoid valve is closed, and the electric lifter drives the hydrogen collector up to the working position. The laser rangefinder is started and reads the initial liquid level height;

[0034] (5) The laser rangefinder detects the liquid level in real time and transmits the data back to the visual control system for data processing and result display;

[0035] (6) When the laser rangefinder detects that the liquid level in the gas collecting bottle is close to the minimum liquid level scale line, the visual control system will issue instructions to repeat the actions of steps (4) and (5) to achieve the purpose of continuous long-term testing. The time for this step is controlled within 30 seconds;

[0036] (7) When the set test time is reached or the stop button is clicked manually, the laser rangefinder reads the final liquid level;

[0037] (8) Equipment start-up termination command: First, the solenoid valve of the hydrogen collector opens to discharge the solution in the gas collecting bottle, and then the electric lift drives the hydrogen collector back to the standby position, and the solenoid valve closes;

[0038] (9) The visual control system processes and displays the final data and can export the experimental results according to needs;

[0039] (10) Finally, clean the experimental equipment, dispose of the experimental waste liquid, and shut down the equipment.

[0040] Key technical points of the present invention:

[0041] 1. The design of the laser rangefinder in the hydrogen collector of the present invention has the function of automatically collecting the liquid level at a fixed time without manual reading; the design of the electromagnetic valve of the hydrogen collector can automatically restore the liquid level in the gas collecting bottle in cooperation with the liquid level reset gear of the electric lifter; compared with the existing technology of using a burette for manual reading, it is more automated and efficient.

[0042] 2. The constant temperature and humidity design of the present invention allows the experimental test environment to be carried out under controllable temperature and humidity conditions, and the hydrogen evolution rate of materials under different temperatures and humidities can be studied without being affected by the temperature and humidity of the external environment. The existing technologies are all open environments, which are greatly affected by the fluctuations of the temperature and humidity of the external environment, thereby affecting the accurate measurement of the hydrogen volume.

[0043] 3. The visual control software of the present invention can automatically process the data of the liquid level change over time collected by the hydrogen collector into the data of the hydrogen volume change over time according to formula (1), and calculate the hydrogen evolution corrosion rate, weight loss corrosion rate and depth method corrosion rate under the corresponding corrosion time according to formulas (2) to (4), and draw a curve chart for visual display. This process does not require human intervention.

[0044] The above technical solution of the present invention has the beneficial effect that: the present invention can carry out long-term experimental tests under constant temperature and humidity conditions, and can avoid the influence on the gas volume caused by the temperature difference between morning and evening and the seasonal temperature change. Therefore, when converting the hydrogen evolution volume rate into the magnesium weight loss rate, the influence of temperature on the gas volume is considered, and the gas molar volume at the experimental set temperature is substituted into the calculation, rather than uniformly using the gas molar volume under the standard state, so that the calculation result is more accurate; in addition, the mechanized automatic operation of the device saves manpower. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the device of the present invention;

[0046] Figure 2 for Figure 1 Section view at AA;

[0047] Figure 3 An enlarged view of the hydrogen collector in the device of the present invention;

[0048] Figure 4 Changes of hydrogen evolution volume and hydrogen evolution rate of the two materials with time.

[0049] In the figure:

[0050] 1——Experimental tank; 2——Fully automatic liquid level control valve;

[0051] 3——sample rack; 4——sample;

[0052] 5——Hydrogen collector; 5A——Laser rangefinder;

[0053] 5B——electromagnetic valve; 5C——gas collecting bottle;

[0054] 5D——highest liquid level scale line; 5E——lowest liquid level scale line;

[0055] 6——Bracket; 7——Temperature sensor;

[0056] 8——Humidity sensor; 9——Thermostat and humidity controller;

[0057] 10——Liquid storage tank; 11——Heating rod;

[0058] 12——catheter; 13——electric lifter;

[0059] 14——Control main board; 15——Visual control system. DETAILED DESCRIPTION

[0060] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the following embodiments. That is, simple equivalent changes and modifications made to the contents disclosed in the present invention should all fall within the scope of invention patent protection.

[0061] [Example 1]

[0062] The present invention is used to test the hydrogen evolution corrosion rate of an AZ31-based composite material in a 3.5wt% NaCl solution and compare it with the AZ31 matrix. Therefore, two sets of hydrogen collectors are required to collect the hydrogen generated by the AZ31 matrix and the AZ31-based composite material respectively. Figure 2 The specific implementation process is as follows:

[0063] 1. First, prepare 15 L of 3.5 wt% NaCl solution, adjust the solution pH to 7, and then inject it into the liquid storage tank (10);

[0064] 2. Prepare 3 samples of AZ31 and AZ31 composite materials, each with a size of 10mm×10mm×10mm, and use epoxy sealing to make the exposed area 1cm 2 , polished to 2000# with silicon carbide sandpaper, cleaned and dried, and then fixed the samples on the sample holder (3);

[0065] 3. Open the visual control system (15), set the experimental parameters as shown in Table 1, and click the start button to start the experiment;

[0066] Table 1 Experimental parameter settings

[0067] Test chamber temperature Humidity of test chamber Liquid storage tank temperature Sampling interval Testing time Material 1 Density Material 2 Density 20℃ 30%RH 20℃ 1h 168h <![CDATA[1.78g / cm 3 ]]> <![CDATA[1.8g / cm 3 ]]>

[0068] 4. The temperature sensor (7) and the humidity sensor (8) monitor the temperature and humidity in the experimental chamber in real time and display them on the visual control system (15). The thermostat (9) works. When the temperature and humidity in the experimental chamber and the temperature of the solution in the liquid storage tank (10) reach the set values, the fully automatic liquid level control valve (2) opens and the solution in the liquid storage tank (10) is injected into the experimental tank (1). When the liquid level in the experimental tank (1) reaches the set value, the fully automatic liquid level control valve (2) closes.

[0069] 5. When the solution is injected into the experimental tank (1), the electric lifter (13) automatically starts, driving the hydrogen collector (5) to descend to the liquid level reset gear, and at the same time the solenoid valve (5B) opens, and the solution enters the gas collecting bottle (5C). After the liquid level reaches the highest liquid level scale line (5D), the solenoid valve (5B) closes, and the electric lifter (13) drives the hydrogen collector (5) to move upward and return to the working gear. At this time, the laser rangefinder (5A) starts to obtain the initial height value of the liquid level in the gas collecting bottle (5C), and the experimental timing begins;

[0070] 6. During the experiment, when the liquid level in the gas collecting bottle (5C) reaches the lowest liquid level mark (5E), the hydrogen collector (5) repeats step 5 to allow the experiment to run for a long time;

[0071] 7. After reaching the set experimental time of 168 hours, the visual control system (15) issues a stop operation command, and the laser rangefinder (5A) obtains the final liquid level and transmits the data back to the visual control system (15). Then, the solenoid valve (5B) of the hydrogen collector (5) opens to discharge the solution in the gas collecting bottle (5C), and the electric lifter (13) drives the hydrogen collector (5) back to the standby position, and the solenoid valve (5B) closes at the same time;

[0072] 8. Save the data in the visual control system (15) and export the experimental results as needed, such as Figure 4 The curves showing the change of hydrogen evolution volume and hydrogen evolution rate of the two materials over time are shown;

[0073] 9. Properly dispose of experimental waste liquid according to laboratory regulations, then clean the equipment and close the equipment for next use.

[0074] The present invention can simply, accurately and efficiently test the hydrogen evolution corrosion rate of magnesium-based materials, avoid the cumbersome process of manual recording and operation, reduce manual errors, and promote the standardization and normalization of the hydrogen evolution corrosion rate measurement of magnesium-based materials.

[0075] [Example 2]

[0076] The present invention is used to test the hydrogen evolution corrosion rate of AZ31 / 6061 layered composite materials in a simulated marine atmospheric environment solution (1g / L NaCl+0.5g / LNa2SO4+0.5g / L CaCl2), and the specific implementation process is as follows:

[0077] 1. First, prepare 10L of 1g / L NaCl+0.5g / L Na2SO4+0.5g / L CaCl2 solution, adjust the solution pH to 7, and then inject it into the liquid storage tank (10);

[0078] 2. Prepare 3 samples of AZ31 and AZ31 composite materials, each with a size of 10mm×10mm×10mm, and use epoxy sealing to make the exposed area 1cm 2 , polished to 2000# with silicon carbide sandpaper, cleaned and dried, and then fixed the samples on the sample holder (3);

[0079] 3. Open the visual control system (15), set the experimental parameters as shown in Table 2, and click the start button to start the experiment;

[0080] Table 2 Experimental parameter settings

[0081] Test chamber temperature Humidity of test chamber Liquid storage tank temperature Sampling interval Testing time Material 1 Density 40℃ 80%RH 40℃ 0.5h 72h <![CDATA[1.78g / cm 3 ]]>

[0082] 4. The temperature sensor (7) and the humidity sensor (8) monitor the temperature and humidity in the experimental chamber in real time and display them on the visual control system (15). The thermostat (9) works. When the temperature and humidity in the experimental chamber and the temperature of the solution in the liquid storage tank (10) reach the set values, the fully automatic liquid level control valve (2) opens and the solution in the liquid storage tank (10) is injected into the experimental tank (1). When the liquid level in the experimental tank (1) reaches the set value, the fully automatic liquid level control valve (2) closes.

[0083] 5. When the solution is injected into the experimental tank (1), the electric lifter (13) automatically starts, driving the hydrogen collector (5) to descend to the liquid level reset gear, and at the same time the solenoid valve (5B) opens, and the solution enters the gas collecting bottle (5C). After the liquid level reaches the highest liquid level scale line (5D), the solenoid valve (5B) closes, and the electric lifter (13) drives the hydrogen collector (5) to move upward and return to the working gear. At this time, the laser rangefinder (5A) starts to obtain the initial height value of the liquid level in the gas collecting bottle (5C), and the experimental timing begins;

[0084] 6. During the experiment, when the liquid level in the gas collecting bottle (5C) reaches the lowest liquid level mark (5E), the hydrogen collector (5) repeats step 5 to allow the experiment to run for a long time;

[0085] 7. After reaching the set experimental time of 72 hours, the visual control system (15) issues a stop operation command, and the laser rangefinder (5A) obtains the final liquid level and transmits the data back to the visual control system (15). Then, the solenoid valve (5B) of the hydrogen collector (5) opens to discharge the solution in the gas collecting bottle (5C), and the electric lifter (13) drives the hydrogen collector (5) back to the standby position, and the solenoid valve (5B) closes at the same time;

[0086] 8. Save the data in the visual control system (15) and export the experimental results as needed;

[0087] 9. Properly dispose of experimental waste liquid according to laboratory regulations, then clean the equipment and close the equipment for next use.

Claims

1. A device for automatically testing the hydrogen evolution rate of magnesium-based metal materials, characterized in that: The device consists of four parts: experimental cabin, auxiliary cabin, operation control cabin and visual control system, among which: The experimental cabin comprises an experimental tank, one side of which is provided with a fully automatic liquid level control valve, and the bottom of the tank is provided with a plurality of sample racks for fixing the tested samples, and the samples are magnesium-based metal materials; a hydrogen collector array is provided directly above the samples; the hydrogen collector is fixed on a tray; the hydrogen collector is composed of a laser rangefinder, an electromagnetic valve and a gas collecting bottle; the laser rangefinder is used to regularly measure the change in the liquid level height in the gas collecting bottle caused by collecting hydrogen, and the electromagnetic valve is used to control the connection and disconnection between the gas collecting bottle and the outside world; the effective volume of the gas collecting bottle is the volume between the highest liquid level scale line and the lowest liquid level scale line of the gas collecting bottle; a temperature sensor and a humidity sensor are also provided in the experimental cabin; The auxiliary cabin includes a thermostat and a liquid storage tank, wherein a heating rod is arranged in the liquid storage tank and is connected to a fully automatic liquid level control valve through a conduit; The operation control cabin includes an electric lifter and a control mainboard array. The electric lifter is arranged at both ends of the tray. The front end of the retractable rod is connected to the tray. The electric lifters at both ends of the tray are linked to each other, thereby driving a group of hydrogen collectors to move up and down. The electric lifter is set with three gears: standby gear, working gear and liquid level reset gear. The functions are to lift the hydrogen collector to the highest point for easy removal of the experimental tank for cleaning, to half immerse the hydrogen collector in the solution for easy collection of hydrogen, and to immerse the hydrogen collector in the solution of the experimental tank and open the solenoid valve to restore the liquid level in the gas collecting bottle to the highest liquid level scale line. The electric lifter starts, and the telescopic rod extends to drive the hydrogen collector down to the liquid level reset position. At this time, the solenoid valve opens to allow the solution to fill the gas collecting bottle. When the liquid level in the gas collecting bottle returns to the highest liquid level scale line, the solenoid valve closes, and the electric lifter drives the hydrogen collector up to the working position. The laser rangefinder starts and reads the initial liquid level height. The laser rangefinder detects the liquid level height in real time and transmits the data back to the visual control system for data processing and result display. The visual control system can control the coordinated operation of various parts of the device according to the set experimental parameters, and process and visualize the acquired data in real time; The thermostat and hygrostat have adjustment ranges of 0 to 80°C and 0 to 99% RH for the temperature and humidity in the experimental chamber respectively; the heating rod can heat the reagent in the liquid storage tank in the range of 0 to 80°C; when the above parameters are set to -1 in the visual control system, they will not work, and the experiment will be carried out using the actual ambient temperature and humidity.

2. The device for automatically testing the hydrogen evolution rate of magnesium-based metal materials according to claim 1, characterized in that: The magnesium-based metal material includes magnesium, magnesium alloys and magnesium-based composite materials.

3. The device for automatically testing the hydrogen evolution rate of magnesium-based metal materials according to claim 1, characterized in that: The laser rangefinder data collection time interval can be adjusted in the range of 1 to 360 minutes per time; three hydrogen collectors are grouped together, and three parallel samples are tested simultaneously to obtain the average value as the final result; there is no less than one group of hydrogen collectors, which can be increased according to test requirements.

4. The device for automatically testing the hydrogen evolution rate of magnesium-based metal materials according to claim 1, characterized in that: The control mainboard is a data collection and operation instruction transmission module, which is connected to various parts through wires, can obtain measurement data of various parts in real time and control coordinated operation, and transmit the measurement data to the visual control system for data processing.

5. The device for automatically testing the hydrogen evolution rate of magnesium-based metal materials according to claim 1, characterized in that: The visual control system can issue operating instructions according to the set experimental parameters to control the coordinated operation of various parts of the entire device, and perform real-time processing and data visualization of the acquired data; Data processing calculation formula: In t =mV max +πr 2 (h0-h t ) (1) According to the ideal gas equation: PV = nRT In formula (1): V t is the volume of hydrogen at test time t (ml), m is the number of liquid level resets, V max is the effective volume of the hydrogen collector (ml), r is the inner radius of the gas collecting bottle (mm), h0 is the initial liquid level (mm), h t is the liquid level height at test time t (mm); In formula (2): P H is the hydrogen evolution rate (mlvcm -2 ·h -1 ), V H is the volume of hydrogen evolution per unit area at time t (ml·cm -2 ), t is the test time (h); In formula (3): P w is the hydrogen evolution rate expressed by weight loss method (g·cm -2 ·h -1 ), T is the set experimental temperature (K); In formula (4): P d is the hydrogen evolution rate expressed by the depth method (mm·y -1 ), ρ is the density of the material being measured (g·cm -3 ); The hydrogen evolution volume V can be obtained by the above formula t , hydrogen evolution rate P H , weight loss corrosion rate P w And the depth method corrosion rate P d The relationship data with the corresponding test time is then plotted to draw a visual curve graph.

6. A method for automatically testing the hydrogen evolution rate of magnesium-based metal materials based on the device according to any one of claims 1 to 5, characterized in that Follow these steps: (1) Prepare the solution and inject it into the liquid storage tank. Fix the sample to be tested on the sample holder and measure the exposed area of ​​the sample. Each group of parallel samples has 3 pieces. (2) Open the visual control system, set the experimental chamber working temperature, humidity, reservoir solution temperature, test time and sampling interval parameters, and then click Start to start the equipment. At this time, the constant temperature and humidity controller and the heating rod start working, and the temperature sensor and humidity sensor monitor the temperature and humidity in the experimental chamber in real time; (3) After the temperature and humidity parameters reach the set values, the valve of the fully automatic liquid level control valve opens, and the solution in the storage tank is injected into the experimental tank through the catheter. After reaching the set height, the valve closes. If the temperature and humidity set values ​​are -1, there is no need to wait; (4) The electric lift drives the hydrogen collector down to the liquid level reset position, at which time the solenoid valve opens to allow the solution to fill the gas collecting bottle. When the liquid level in the gas collecting bottle returns to the highest liquid level mark, the solenoid valve closes, and the lift drives the hydrogen collector up to the working position, then the laser rangefinder starts and reads the initial liquid level height value; (5) The laser rangefinder detects the change of liquid level in real time and transmits the data back to the visual control system for data processing and result display; the displayed results include but are not limited to the hydrogen evolution rate P H (ml·cm -2 ·h -1 ), magnesium corrosion rate P w (g·cm -2 ·h -1 or mm·y -1 ) and their changes over time; (6) When the laser rangefinder detects that the liquid level in the gas collecting bottle reaches the lowest liquid level scale line, the visual control system will issue an instruction to repeat the actions of steps (4) and (5) to achieve the purpose of continuous long-term testing; (7) When the set test time is reached or the stop button is clicked manually, the laser rangefinder reads the final liquid level; (8) Equipment start-up termination command: First, the solenoid valve of the hydrogen collector opens to discharge the solution in the gas collecting bottle, and then the electric lift drives the hydrogen collector back to the standby position, and the solenoid valve closes; (9) The visual control system processes and displays the final data and can export the experimental results according to needs; (10) Finally, clean the experimental equipment, dispose of the experimental waste liquid, and shut down the equipment.

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