Device for accurately measuring polarization curve of metal by forming thin liquid film on metal surface

Abstract

The invention discloses a device for forming a thin liquid film on a metal surface to accurately measure a metal polarization curve, and belongs to the technical field of metal polarization curve measurement. In a metal polarization curve measurement process, a uniform and controllable thin liquid film is difficult to form on a metal surface by a traditional method, so that the measurement precision is influenced. In order to solve the problem, the device comprises an electrolyte control unit and a thin liquid film generation unit, the electrolyte control unit comprises a solution storage tank and a peristaltic pump, and the thin liquid film generation unit comprises an atomizer, a compressed air pipeline and a sample table with an adjustable inclination angle. The peristaltic pump conveys the electrolyte to the atomizer, and atomized liquid drops generated by the atomizer reach the surface of the metal sample through the compressed air pipeline. The thickness of the thin liquid film is kept uniform and controllable through combination of inclination angle adjustment of the sample table and atomization amount adjustment of the atomizer. The device is mainly used for accurately measuring the metal polarization curve, and the accuracy and reliability of measurement can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal polarization curve measurement, and in particular relates to a device for precisely measuring the metal polarization curve by forming a thin liquid film on the metal surface. Background Technique

[0002] In the field of metal polarization curve measurement, obtaining accurate measurement results is crucial for studying the corrosion performance, electrochemical characteristics, etc. of metals. However, there are many challenges in the current measurement process, seriously affecting the accuracy and reliability of the measurement. Forming a suitable thin liquid film on the metal surface is the key prerequisite for accurately measuring the metal polarization curve. However, existing technical means are difficult to form a uniform and controllable thin liquid film on the metal surface. On the one hand, the traditional electrolyte supply method lacks precise flow control, resulting in unstable electrolyte volume reaching the metal surface. For example, common simple pouring or dropping methods cannot accurately adjust the electrolyte volume according to actual needs, causing problems of uneven thickness in the initial stage of thin liquid film formation. This is because these methods do not consider the precise requirements for electrolyte volume under different experimental conditions and only rely on empirical operations, lacking scientific quantitative control. On the other hand, in the atomization and liquid film forming links, there is a lack of an effective coordinated adjustment mechanism. In existing devices, the atomization amount of the atomizer is often fixed or has a limited adjustment range and cannot be flexibly adjusted according to the real-time state of the thin liquid film. At the same time, the sample stage usually does not have an inclination adjustment function or has extremely low adjustment accuracy. This makes it impossible to effectively control the liquid film thickness using the gravity effect when forming the thin liquid film. When the liquid film is too thick or too thin, it is difficult to quickly restore to a suitable thickness by adjusting the atomization amount and the inclination of the sample stage, thus unable to ensure that the thin liquid film maintains a uniform and controllable state throughout the measurement process. In addition, in controlling the thin liquid film thickness, traditional technologies do not establish an effective feedback adjustment system. Since the thin liquid film thickness cannot be measured accurately and in real time, it is difficult to adjust relevant parameters according to the measurement results. During the actual measurement process, experimenters are difficult to know whether the liquid film thickness meets the requirements and can only find problems after the measurement ends, resulting in a waste of a large amount of time and resources. Moreover, even if it is realized that there are problems with the liquid film thickness, there are no corresponding technical means for timely and effective adjustment, making it difficult to ensure the accuracy and repeatability of the measurement results. Once when trying to solve these problems, difficulties in technology integration and cost control were faced. To achieve precise electrolyte flow control, flexible atomization amount adjustment, and accurate sample stage inclination adjustment, multiple high-precision components need to work together. However, integrating these components into a device not only requires solving technical compatibility problems but also faces the challenge of a significant increase in cost. At the same time, developing a high-precision thin liquid film thickness measurement device and the corresponding feedback control system also requires a large amount of R & D resources and time. These difficulties have long made it impossible to effectively solve the key problem of forming a uniform and controllable thin liquid film during the metal polarization curve measurement process, seriously restricting the development of related research. Summary of the Invention

[0003] One object of the present invention is that in the measurement of the metal polarization curve, it is difficult to form a uniform and controllable thin liquid film on the metal surface by conventional methods, resulting in limited measurement accuracy. This technical solution aims to achieve the uniform control of the thin liquid film by designing a specific device structure, providing a basic condition for accurately measuring the metal polarization curve.

[0004] The prior art only realizes the preliminary generation of the thin liquid film, lacking real-time monitoring and precise control of the thickness of the thin liquid film, as well as automatic control during the measurement process. This claim solves the problems of how to accurately measure the thickness of the thin liquid film in real time, automatically adjust the device parameters according to the measurement results, start the measurement, and process the measurement data.

[0005] During the adjustment process of the thin liquid film thickness, when the thickness exceeds the preset range, there is a lack of an effective quantitative adjustment method. This claim solves the problem of how to accurately adjust the atomization amount and the inclination angle of the sample stage according to the deviation between the thin liquid film thickness and the preset value, so that the thin liquid film thickness can quickly return to the preset range.

[0006] For the adjustment of the inclination angle of the sample stage, a more specific structural design is required to ensure the accuracy and stability of the adjustment; at the same time, the electrolyte control unit also needs to be optimized. This claim solves the optimization of the sample stage inclination adjustment structure, as well as problems such as the monitoring of the electrolyte temperature and liquid level and the selection of the storage tank material, improving the overall performance of the device.

[0007] To further improve the quality of the thin liquid film and the measurement accuracy, it is necessary to accurately define the parameters of the atomized droplets, fiber optic spectrometer, and peristaltic pump. This claim solves the problem of how to make the thin liquid film more uniform and the measurement more accurate by optimizing the parameters of key components.

[0008] The prior art's method for adjusting the atomization amount is not precise enough. This claim solves the problem of how to more precisely adjust the driving power of the atomizer according to the deviation of the thin liquid film thickness, and thus more accurately control the thickness of the thin liquid film.

[0009] In terms of the dynamic balance control of the thin liquid film thickness, a more scientific adjustment method and precise adjustment range setting are required. This claim solves the problem of how to set the initial value based on a theoretical formula and achieve high-precision dynamic stability of the thin liquid film thickness through non-linear coupling adjustment.

[0010] When the conventional adjustment method cannot restore the thin liquid film thickness to normal, there is a lack of backup adjustment means. This claim solves the problem of how to start the backup adjustment mechanism to ensure that the thin liquid film thickness returns to normal in the case of continuous ineffective adjustment.

[0011] To this end, the present invention provides a device for precisely measuring the polarization curve of a metal by forming a thin liquid film on the metal surface, comprising: an electrolyte control unit including a solution storage tank and a peristaltic pump; a thin liquid film generating unit including an atomizer, a compressed air pipeline, and a sample stage with an adjustable inclination angle. The peristaltic pump transports the electrolyte in the solution storage tank to the atomizer; the atomizer atomizes the electrolyte into droplets, and transports the atomized droplets to the surface of the metal sample disposed on the sample stage through the compressed air pipeline; wherein, the sample stage has a certain inclination angle adjustment range, and the atomizer is configured with an atomization amount adjustment function; the inclination angle adjustment and the atomization amount adjustment are combined to maintain a thin liquid film with a uniform and controllable thickness in a gas-liquid equilibrium state between the thin liquid film and the mist flow.

[0012] In addition, it further includes a reference electrode and a counter electrode, which are disposed above the sample stage. Slots for inserting the reference electrode and the counter electrode are provided on the sample stage. After the sample stage is tilted, the reference electrode and the counter electrode are inserted into the slots.

[0013] Preferably, the present invention further includes a control module, which is signal-connected to the atomizer and the sample stage; a thin liquid film monitoring unit including an optical fiber spectrometer, which measures the thickness of the thin liquid film in real time and feeds it back to the control module through multi-point monitoring; when the control module receives the thin liquid film thickness data, first, it determines whether the current thin liquid film thickness is stable within the target range; if the thickness is unstable, the control module controls and adjusts the atomization amount of the atomizer and the inclination angle of the sample stage; after the thin liquid film thickness is stable, the control module sends an instruction to the electrochemical workstation to start the measurement of the metal polarization curve; the electrochemical workstation applies different potentials to the metal sample through the working electrode, reference electrode, and auxiliary electrode connected to the metal sample; during the application of the potential, the electrochemical workstation collects the current data flowing through the metal sample in real time; the collected current data is transmitted back to the control module in real time, and the control module integrates these current data with the corresponding potential data to plot the metal polarization curve under the current thin liquid film thickness and environmental conditions.

[0014] Preferably, when the thickness of the thin liquid film measured by the fiber optic spectrometer of the present invention exceeds the preset upper limit value, the control module adjusts as follows: In the control module, there is a preset corresponding relationship between different thickness differences and the degree of reduction in the atomization amount. Based on the difference between the currently measured thickness of the thin liquid film and the preset upper limit value, this corresponding relationship is searched to determine the reduction amplitude of the atomizer driving power. By adjusting the duty cycle of the electrical signal driving the atomizer, the number of droplets in the mist flow is reduced. At the same time, the control module determines the angle by which the sample stage needs to be increased according to the built-in corresponding relationship between the thickness difference and the increased angle of inclination, sends a signal to the stepper motor connected to the support structure of the sample stage, drives the stepper motor to rotate, increases the inclination angle of the sample stage, and accelerates the flow rate of the thin liquid film under the action of gravity to reduce the film thickness. When the thickness of the thin liquid film measured by the fiber optic spectrometer is lower than the preset lower limit value, the control module increases the atomizer driving power according to the built-in corresponding relationship to increase the number of droplets in the mist flow, and sends a reverse signal to the stepper motor to reduce the inclination angle of the sample stage and slow down the flow rate of the thin liquid film to increase the film thickness.

[0015] Preferably, the inclination angle adjustment of the sample stage of the present invention is achieved through the following structure: The output shaft of the stepper motor is connected to a lead screw, and a nut cooperating with the lead screw is provided at the bottom of the sample stage; One side of the sample stage is hinged to the fixed base through a rotating shaft and can rotate around this rotating shaft; The electrolyte control unit also includes a constant temperature heating plate for controlling the electrolyte temperature at 25°C to 50°C, with a temperature fluctuation degree ≤ ±1°C; It also includes a liquid level indicating sensor; The solution storage tank of the electrolyte control unit is made of acrylic material, with dimensions of length × width × height 400mm × 400mm × 200mm, and has acid and alkali resistance, weather resistance, and an E1 class formaldehyde release standard.

[0016] Preferably, the particle size of the atomized droplets of the present invention < 5μm, and the atomization rate ≥ 0.15 ml / min; The measurement range of the fiber optic spectrometer is 10μm to 1000μm, the measurement accuracy ≤ 5nm, and it supports multi-point real-time monitoring; The peristaltic pump adjusts the flow rate to 0.02 - 2200 ml / min and the rotation speed to 0.1 - 600 rpm; Among them, the fiber optic spectrometer includes a fiber optic probe array, a spectral acquisition module, and a data processing module; The fiber optic probe array consists of multiple fiber optic probes evenly distributed at different positions above the sample stage, and each fiber optic probe is connected to the spectral acquisition module; The spectral acquisition module is used to collect the optical signals transmitted by each fiber optic probe and convert them into spectral data; The data processing module is connected to the spectral acquisition module, receives the spectral data, and calculates the thickness of the thin liquid film at the corresponding position of each fiber optic probe based on the spectral data; The fiber optic spectrometer simultaneously collects optical signals at multiple positions through the fiber optic probe array to achieve multi-point real-time monitoring of the thin liquid film.

[0017] Preferably, when the thickness of the thin liquid film measured by the fiber optic spectrometer exceeds the preset upper limit value, the control module performs the following operations: In the control module, there is a pre-stored correspondence between different thickness differences and the degree of atomization reduction presented in the form of a table. The thickness differences in the table are divided at intervals of 5 μm, starting from 5 μm above the preset upper limit value and up to 100 μm above the preset upper limit value, with a total of 20 intervals; the degree of atomization reduction is expressed as a percentage, starting from 5%, and for each interval of 5 μm thickness difference, the degree of atomization reduction increases by 2%. The control module obtains the difference between the currently measured thickness of the thin liquid film and the preset upper limit value, accurate to 0.1 μm, and performs linear interpolation search in the above table based on this difference to determine the corresponding degree of atomization reduction, and then determines the reduction amplitude of the atomizer drive power, with an accuracy of 0.1%. The control module adjusts the duty cycle of the electrical signal driving the atomizer through Pulse Width Modulation (PWM) technology. The frequency of the electrical signal is set to 20 kHz, and the duty cycle adjustment accuracy is 0.1%, so as to reduce the number of droplets in the mist flow and make the thickness of the thin liquid film return to the preset range.

[0018] Preferably, the inclination angle adjustment range of the sample stage of the present invention is from 0° to 60°, and the adjustable range of the atomization amount of the atomizer is 0.02 - 2200 ml / min; the device realizes the dynamic balance control of the thin liquid film thickness through the following steps: a. Based on the Nusselt theory formula, set the initial values of the inclination angle α and the atomization amount Q corresponding to the target liquid film thickness δ; b. Real-time monitor the liquid film thickness through the fiber optic spectrometer. If the measured thickness deviates from the set value, then jointly adjust the inclination angle α and the atomization amount Q to make the liquid film condensation rate and the flow rate reach equilibrium; c. Repeat step b until the liquid film thickness is stable within the set deviation range ≤ 0.5%; the adjustment of the inclination angle α and the atomization amount Q satisfies the following relationship: [specific relationship formula]. Through this non-linear coupling adjustment, overcome the hysteresis of single-parameter control and achieve high-precision dynamic stability of the liquid film thickness.

[0019] Preferably, for the device for forming a thin liquid film on the metal surface to accurately measure the metal polarization curve, the inclination angle adjustment range of the sample stage is from 0° to 60°, and the adjustable range of the atomization amount of the atomizer is 0.02 - 2200 ml / min;

[0020] The device realizes the dynamic balance control of the thin liquid film thickness through the following steps:

[0021] a. Based on the Nusselt theory formula, set the initial values of the inclination angle α and the atomization amount Q corresponding to the target liquid film thickness δ;

[0022]

[0023] where, μ L is the dynamic viscosity of the electrolyte; K LThermal conductivity of the electrolyte; Z is the coordinate along the length of the sample stage; T sat is the saturation temperature of the atomized droplets; T w is the surface temperature of the metal sample; ρ L is the mass density of the electrolyte, ρ G is the mass density of the gas in the atomization box; g is the acceleration due to gravity; h LG Latent heat of vaporization of the electrolyte;

[0024] b. Monitor the thickness of the liquid film in real time through a fiber optic spectrometer. If the measured thickness deviates from the set value, the inclination angle α and the atomization amount Q are adjusted in conjunction to achieve a balance between the liquid film condensation rate and the flow rate;

[0025] c. Repeat step b until the film thickness is stable within the set deviation range ≤ 0.5%;

[0026] The adjustment of the inclination angle α and the atomization amount Q satisfies the following relationship:

[0027]

[0028] Through this nonlinear coupling adjustment, the hysteresis of single parameter control is overcome and high-precision dynamic stability of liquid film thickness is achieved.

[0029] Preferably, the device for forming a thin liquid film on the metal surface to accurately measure the metal polarization curve is characterized in that, during the process of the control module adjusting the reduction amplitude of the atomizer driving power, if the thickness of the thin liquid film has not recovered to within the preset range after three consecutive adjustments, the control module will start the backup adjustment mechanism to reduce the flow rate of the electrolyte delivered to the atomizer by 10% of the current flow rate, and at the same time reduce the inclination angle of the sample stage by 5°, and monitor the change of the thickness of the thin liquid film in real time until the thickness of the thin liquid film returns to normal.

[0030] Preferably, the device for forming a thin liquid film on a metal surface to accurately measure a metal polarization curve is characterized in that the particle size of the atomized droplets ranges from 1 μm to 4 μm;

[0031] The nozzle is made of ceramic material and has a tapered structure. The surface of the ceramic nozzle is roughened at the nano level. The average size of the protrusions and grooves formed by the roughening treatment is between 50 and 200 nanometers.

[0032] Moreover, the reference electrode and the counter electrode are connected to the control module of the sample stage through wireless signals; when the sample stage is tilted to a preset angle, the control module activates the electrode driving unit based on the inclination sensor signal, so that the reference electrode and the counter electrode move along a preset path to contact the sample surface; after the electrode contacts the sample, the control module monitors the contact impedance in real time and dynamically adjusts the electrode pressure through closed-loop feedback until the impedance value is stable within the set threshold range; the surface of the electrode is coated with a self-healing hydrophobic coating, and the coating is deformed under pressure when the electrode contacts the sample, forming a continuous sealing interface to block the penetration of the electrolyte.

[0033] Preferably, for the device for forming a thin liquid film on the metal surface to accurately measure the metal polarization curve, when the inclination angle adjustment and the atomization amount adjustment are combinedly executed, the control module adopts a fuzzy control algorithm; this algorithm is based on fuzzy logic and takes the thickness deviation of the thin liquid film measured by the fiber optic spectrometer and the deviation change rate as input variables;

[0034] In the fuzzification stage, the thickness deviation of the thin liquid film is divided into 7 fuzzy subsets of "negative large", "negative medium", "negative small", "zero", "positive small", "positive medium", and "positive large", and the corresponding universe of discourse is [-30μm, -20μm, -10μm, 0μm, 10μm, 20μm, 30μm]; the deviation change rate of the thickness is divided into 7 fuzzy subsets of "negative large", "negative medium", "negative small", "zero", "positive small", "positive medium", and "positive large", and the corresponding universe of discourse is [-5μm / s, -3μm / s, -1μm / s, 0μm / s, 1μm / s, 3μm / s, 5μm / s];

[0035] The fuzzy rule base contains 49 fuzzy rules. For example, when the thickness deviation is "positive large" and the deviation change rate is "positive large", the fuzzy rule indicates a large reduction in the atomization amount and a large increase in the inclination angle of the sample stage; when the thickness deviation is "zero" and the deviation change rate is "zero", keep the current atomization amount and the inclination angle of the sample stage unchanged;

[0036] In the defuzzification stage, the centroid method is used to convert the output result obtained by fuzzy inference into specific atomization amount adjustment values and sample stage inclination angle adjustment values. The atomization amount adjustment accuracy is 0.01 ml / min, and the sample stage inclination angle adjustment accuracy is 0.1°.

[0037] Beneficial effects

[0038] Through the collaborative work of the electrolyte control unit and the thin liquid film generation unit, the device realizes the formation of a uniform and controllable thin liquid film on the metal surface. This lays a foundation for accurately measuring the metal polarization curve, making the measurement results more capable of reflecting the true electrochemical characteristics of the metal. Compared with traditional methods, the uniform and controllable thin liquid film reduces the measurement error caused by uneven liquid film thickness, improves the accuracy and reliability of the measurement, and helps researchers to more deeply study the corrosion, electrochemistry and other properties of metals.

[0039] After adding the control module and the thin liquid film monitoring unit, the real-time monitoring and automatic adjustment of the thin liquid film thickness are realized. The control module can adjust the atomization amount and the inclination angle of the sample stage in a timely manner according to the monitoring data, ensuring the stability of the thin liquid film thickness and creating stable conditions for measurement. At the same time, the functions of automatically starting the measurement and integrating the data to draw curves improve the measurement efficiency, reduce the errors caused by manual operation, and make the measurement process more convenient, efficient and accurate.

[0040] The precise thickness adjustment mechanism can quickly respond to the situation where the thin liquid film thickness exceeds the preset range. Through the preset corresponding relationship, the atomizer and the sample stage are accurately adjusted to ensure that the thin liquid film thickness is always within the appropriate range. This further improves the stability of the thin liquid film, reduces the influence of the liquid film thickness fluctuation on the measurement result, enhances the adaptability of the device under different working conditions, and ensures the accuracy and repeatability of the metal polarization curve measurement.

[0041] The optimized inclination angle adjustment structure of the sample stage ensures the accuracy and stability of the adjustment, making the flow control of the thin liquid film under the action of gravity more precise. The electrolyte control unit adds a constant temperature heating plate, a liquid level indicating sensor, and a storage tank made of a specific material, ensuring the stability of the electrolyte temperature, the knowability of the liquid level, and the durability and environmental protection of the storage tank. These improvements enhance the overall performance of the device, provide a more stable experimental environment for measurement, and are conducive to obtaining more reliable measurement results.

[0042] The precise limitation of the parameters of the atomized droplets, the fiber optic spectrometer and the peristaltic pump improves the quality of the thin liquid film and the measurement accuracy. The droplets with small particle size and high atomization rate make the thin liquid film more uniform; the fiber optic spectrometer with high precision, wide measurement range and supporting multi-point monitoring can obtain the thin liquid film thickness information more accurately; the peristaltic pump with a wide adjustable range ensures the stable supply of the electrolyte. All these contribute to improving the accuracy and reliability of the metal polarization curve measurement.

[0043] A more precise atomization amount adjustment method can more finely control the number of droplets in the fog flow, and then more accurately adjust the thin liquid film thickness. The use of the corresponding relationship in the form of a table, the high-precision linear interpolation search, and the precise PWM adjustment technology make the adjustment accuracy higher. This effectively reduces the small fluctuations of the thin liquid film thickness, provides a more stable thin liquid film condition for accurately measuring the metal polarization curve, and improves the accuracy and reliability of the measurement.

[0044] Based on the theoretical formula, the initial value is set, and the non-linear coupling adjustment method is adopted to overcome the hysteresis of the single parameter control. The high-precision dynamic stability of the thin liquid film thickness is realized, which can quickly respond to external disturbances and maintain the stability of the liquid film thickness. This enables the accurate measurement of the metal polarization curve in a complex environment, improves the adaptability of the device and the accuracy of the measurement, and provides more reliable data support for related research.

[0045] The backup adjustment mechanism provides additional safeguards for the device. When the conventional adjustment method fails, it can promptly activate the backup plan to adjust the electrolyte flow rate and the inclination angle of the sample stage, restoring the thickness of the thin liquid film to normal. This enhances the stability and reliability of the device, avoids measurement interruption caused by adjustment failure, reduces experimental costs and time waste, and ensures the smooth progress of the measurement of the metal polarization curve. Brief Description of the Drawings

[0046] Figure 1 It is a schematic diagram of the working principle of the thin liquid film device;

[0047] Figure 2 It is a schematic diagram of the formation of the thin liquid film;

[0048] Figure 3 It is a schematic diagram of the formation and flow of the thin liquid film on a flat plate according to an embodiment of the present invention;

[0049] Figure 4 It is a schematic diagram of the stable process of the thin liquid film thickness over time according to an embodiment of the present invention;

[0050] Figure 5 It is a schematic diagram of the electrode arrangement according to an embodiment of the present invention.

[0051] Reference Signs: 1, Electrochemical workstation; 2, Thin liquid film; 3, Counter electrode; 4, Sealing groove; 5, Sample stage; 6, Lead screw; 7, Metal sample; 8, Reference electrode Detailed Description of the Embodiments

[0052] The following further elaborates on the present invention in conjunction with the accompanying drawings, enabling those skilled in the art to implement it with reference to the text of the specification.

[0053] As Figures 1 - 5As shown, according to an embodiment of the present invention, the electrolyte control unit includes a solution storage tank and a peristaltic pump. The volume of the solution storage tank can be selected as 400mm×400mm×200mm, the material can be selected as acrylic board, with a thickness of 5mm, the surface is smooth and the acid and alkali resistance performance meets the E1 standard. The peristaltic pump can be selected as the BT100-1F type of Longer Company, with a flow rate adjustment range of 0.02-2200ml / min and a rotation speed adjustment range of 0.1-600rpm. The hose of the peristaltic pump can be selected as silicone material, which is corrosion-resistant and has high flexibility. The solution storage tank is installed on the left side of the device base and is connected to the peristaltic pump through a silicone hose. The peristaltic pump is fixed on the right side of the storage tank, and the outlet pipe extends to the atomizer. The flow rate of the peristaltic pump is set through the control panel with an accuracy of 0.1ml / min, and the liquid level sensor monitors the liquid level of the storage tank in real time to trigger a low liquid level alarm. In the function test, the stability error of the peristaltic pump at different flow rates is ≤±2%, and there is no leakage in the airtightness test of the storage tank. This unit can stably supply the electrolyte, avoid experiment interruption, and improve the reliability of the device.

[0054] The thin liquid film generation unit includes an atomizer, a compressed air pipe and a sample stage with adjustable inclination. The atomizer can be selected as the NE-U17 type of Omron, with an atomization rate ≥0.15ml / min and the droplet size <5μm. The compressed air pipe can be selected as stainless steel material, with an inner diameter of 6mm and a pressure resistance ≥0.8MPa. The sample stage can be selected as aluminum alloy material, with a polished surface, an inclination adjustment range of 0°-60°, and an adjustment accuracy of 0.1°. The atomizer is installed 30cm above the sample stage and is connected to the compressed air source through a stainless steel pipe. The sample stage is hinged to the base through a rotating shaft, and the stepping motor drives the lead screw to adjust the inclination. The atomizer atomizes the electrolyte into droplets, and the compressed air blows the droplets onto the sample surface at a pressure of 0.3MPa. In the experimental verification, the droplet size of the atomized liquid is detected by a laser particle size analyzer and meets the requirements, and the deviation of the liquid film thickness uniformity at different inclinations is ≤±5%. This unit optimizes the initial distribution and flow control of the thin liquid film through uniform atomization and inclination adjustment.

[0055] The adjustment mechanism maintains a uniform and controllable thickness of the thin liquid film by combining the adjustment of the sample stage inclination angle and the atomization amount. The control module can select the Siemens S7-1200 PLC, with a preset target thickness deviation ≤ 0.5%, and an adjustment response time ≤ 3 seconds. The fiber optic spectrometer can be the Ocean Optics HR4000 type, with a measurement range of 10 - 1000 μm, an accuracy of 5 nm, and the probe array is installed 10 cm above the sample stage. The stepper motor drives the T-screw to adjust the inclination angle, with a pitch of 2 mm and an accuracy of ±0.01 mm. The control module receives the data from the fiber optic spectrometer, calculates the deviation through the PID algorithm (Kp = 0.8, Ki = 0.2, Kd = 0.1), preferentially adjusts the inclination angle, and supplements it with the adjustment of the atomization amount. In the experimental test, the simulated thickness fluctuation is ±10%, and the proportion of the steady-state error ≤ 2 μm is ≥ 95%. This mechanism realizes the high-precision dynamic stability of the liquid film thickness, reduces manual intervention, and improves the measurement automation level.

[0056] The pre-configured electrolyte is stored in the solution storage tank of the electrolyte control unit. The peristaltic pump extracts the electrolyte from the storage tank through a silicone hose, with the flow rate set at 0.02 - 2200 ml / min and the rotation speed adjustment range of 0.1 - 600 rpm. The peristaltic pump transports the electrolyte to the liquid inlet of the atomizer, and the atomizer atomizes the electrolyte into droplets with a particle size < 5 μm through ultrasonic vibration or compressed air fragmentation. The compressed air pipeline blows the atomized droplets onto the metal specimen on the surface of the sample stage at a pressure of 0.3 MPa to form an initial thin liquid film.

[0057] The sample stage adjusts the inclination angle through the stepper motor-driven screw mechanism, with an angle range of 0° - 60° and an adjustment accuracy of 0.1°. The initial inclination angle is preset to 10° - 30° according to the target liquid film thickness. After the droplets condense on the sample surface, they flow along the inclined surface under the action of gravity to form a continuous thin liquid film. The fiber optic spectrometer monitors the liquid film thickness in real time through a multi-point probe, with a measurement range of 10 - 1000 μm and an accuracy of 5 nm. If the liquid film thickness exceeds the preset range (such as the target value is 50 μm ± 0.5%), the control module triggers the adjustment mechanism.

[0058] The control module receives the thickness data from the fiber optic spectrometer and calculates the deviation using the PID algorithm. When the liquid film thickness exceeds the upper limit (such as 50.25 μm), the stepper motor increases the inclination angle of the sample stage by 5°, and at the same time reduces the driving power of the atomizer by 10% to reduce the droplet generation amount. When the thickness is lower than the lower limit (such as 49.75 μm), the stepper motor reduces the inclination angle by 3° and increases the atomizer power by 15%. The adjustment process continues until the liquid film thickness stabilizes within the target range, and then the electrochemical workstation 1 is started, a stepped potential is applied, and the current data is recorded to plot the polarization curve. Under steady state, the liquid film thickness fluctuation ≤ 2 μm, and the measurement error is reduced to 1 / 5 of the traditional method.

[0059] The silicone hose of the peristaltic pump is acid and alkali resistant to avoid the corrosion of the electrolyte; the liquid level sensor monitors the liquid volume in the storage tank and suspends the experiment when the liquid level is low. The compressed air pressure is precisely controlled by a pressure reducing valve to ensure the uniform distribution of the atomized droplets; the nozzle's tapered design reduces the collision and agglomeration of droplets. For every full rotation of the lead screw mechanism (pitch 2 mm), the inclination angle changes by 0.1°, and the pulse control accuracy of the stepper motor is ±0.01 mm. The fiber optic spectrometer scans once every 5 seconds, and the data is uploaded to the control module in real time. Multi-point monitoring avoids abnormal local thickness. The PID parameters (Kp = 0.8, Ki = 0.2, Kd = 0.1) optimize the response speed, prioritize the adjustment of the inclination angle, and fine-tune the atomization amount for assistance.

[0060] Experimental verification and effects: 1. Liquid film uniformity test: Under the conditions of an inclination angle of 20° and an atomization rate of 0.2 ml / min, 10 repeated experiments show that the standard deviation of the liquid film thickness ≤ 1.2 μm. 2. Adjustment response test: Simulating a sudden increase in the liquid film thickness by 10 μm, the system returns to the target range within 2.8 seconds, and the overshoot ≤ 3%. 3. Polarization curve comparison: Compared with the traditional immersion method, the corrosion potential error measured by the thin liquid film device is reduced to ±5 mV, and the repeatability of the current density is increased to 98%.

[0061] According to another embodiment of the present invention, the control module can select the Siemens S7-1200 PLC, which supports the Modbus communication protocol and is connected to the fiber optic spectrometer through the RS485 interface. The fiber optic spectrometer can be the Ocean Optics HR4000 type, with a measurement range of 10 - 1000 μm, an accuracy of 5 nm. The fiber optic probe array consists of 8 quartz probes, evenly distributed 10 cm above the sample stage. The probe holder can be made of aluminum alloy and is fixed to the top beam of the device. The control module receives the spectrometer data in real time, with a sampling frequency of 1 time per second. In the functional test, the standard deviation of the multi-point monitoring data ≤ 1.5 μm. The experimental object is a 304 stainless steel specimen, and the experimental method is to repeat the measurement 10 times and statistically calculate the average thickness and the fluctuation range. This design enables the real-time and precise monitoring of the thin liquid film 2 thickness, providing a data basis for subsequent adjustments.

[0062] The control module presets the target thickness deviation threshold to ±0.5% (for example, when the target value is 50μm, the threshold range is 49.75 - 50.25μm). When the measured thickness exceeds the upper limit value, the control module adjusts the driving power of the atomizer according to a preset table (for every 5μm increase in thickness difference, the atomization amount decreases by 2%), and the stepping motor synchronously increases the tilt angle of the sample stage with a step size of 0.1°. The atomizer can be the Omron NE-U17 type, and the driving power adjustment accuracy is 0.1%. The tilt angle adjustment mechanism of the sample stage uses a T-shaped lead screw with a pitch of 2mm. The stepping motor can be the Oriental Motor PKP series, and the pulse control accuracy is ±0.01mm. In the experimental verification, when the simulated thickness suddenly increases by 10μm, the system returns to the target range within 3 seconds, and the proportion of the steady-state error ≤2μm is ≥95%. This mechanism ensures the rapid stability of the liquid film thickness and reduces manual intervention.

[0063] The electrochemical workstation can be the Princeton PARSTAT 4000 type, which connects the working electrode, reference electrode (Ag / AgCl), and auxiliary electrode (platinum sheet) of the metal specimen through BNC interfaces. After the liquid film thickness is stable, the control module sends a start command, and the electrochemical workstation applies a stepped potential according to a preset program (step size 10mV, scan rate 1mV / s), collects current data in real time, and transmits it to the control module. Data integration is completed through LabVIEW software, a potential-current curve is plotted, and it is saved in CSV format. The experimental object is a copper alloy specimen. The experimental method is to compare the measurement results of the traditional immersion method and the thin liquid film device, and statistically analyze the corrosion potential error. This process realizes fully automated measurement, and the repeatability error of the polarization curve is ≤3%, improving the experimental efficiency.

[0064] Description of technical effects: 1. Improvement in monitoring accuracy: The multi-point monitoring of the fiber optic spectrometer controls the thickness fluctuation within ±1.5μm. 2. Optimization of adjustment response: The closed-loop control enables the liquid film thickness recovery time to be ≤3 seconds, and the steady-state error to be ≤2μm. 3. Increase in measurement efficiency: The automated operation of the electrochemical workstation reduces manual time consumption, and the data repeatability error is ≤3%.

[0065] According to another embodiment of the present invention, the thickness difference correspondence table preset in the control module is divided at intervals of 5μm, starting from 5μm above the preset upper limit value and ending at 100μm above the upper limit value, with a total of 20 intervals. For example, when the target thickness is 50μm, a thickness difference of 5μm corresponds to a 5% reduction in the atomization amount, and for every 5μm increase in the difference, the degree of reduction in the atomization amount increases by 2%. The control module can be the Siemens S7-1200 PLC, which supports a linear interpolation algorithm, and the difference calculation accuracy is 0.1μm. The data table is stored in the EEPROM of the PLC and can be modified through the upper computer software. In the experimental verification, when the simulated thickness deviation is 50μm, after the system adjusts according to the table, the time for the liquid film thickness to return to the target value is ≤4 seconds, and the error is ≤1.5μm. This design realizes the quantitative adjustment of the thickness deviation and improves the control accuracy.

[0066] The atomizer drive power adjustment uses Pulse Width Modulation (PWM) technology. The frequency of the electrical signal is set at 20 kHz, and the duty cycle adjustment accuracy is 0.1%. The atomizer can be the Omron NE-U17 model, with a drive power range of 10 - 100 W and a corresponding atomization rate of 0.02 - 0.25 ml / min. When the thickness difference exceeds the preset upper limit of 5 μm, the control module reduces the drive power according to the interpolation result. For example, when the difference is 10 μm, the power is reduced by 7%. The power signal is output to the atomizer through the PWM module, and the step size of the duty cycle change is 0.1%. The experimental object is an aluminum alloy specimen, and the experimental method is 10 consecutive adjustment tests. The results show that the linearity error of the atomization amount change is ≤2%. This mechanism ensures the accuracy and response speed of the atomization amount adjustment.

[0067] The adjustment of the sample stage tilt angle is achieved by driving a T-screw with a stepper motor. The screw can be made of stainless steel with a pitch of 2 mm, and the stepper motor can be the Oriental Motor PKP series, with a step angle of 1.8° and the drive pulse subdivision set to 16 subdivisions. The angle adjustment accuracy is 0.1°. When the thickness difference exceeds the upper limit of 5 μm, the control module increases the tilt angle according to the built-in relationship table. For example, when the difference is 10 μm, the tilt angle increases by 0.3°. After receiving the pulse signal, the stepper motor rotates and pushes the sample stage to rotate around the rotation axis through the screw. In the experimental verification, the repeat positioning accuracy of the tilt angle adjustment is ±0.05°, and the liquid film flow velocity is increased by 15%. This design realizes the high-precision and rapid adjustment of the tilt angle through mechanical structure optimization.

[0068] Technical effect description: 1. Adjustable quantification and controllability: The thickness difference - atomization amount correspondence table standardizes the adjustment process, with an error ≤1.5 μm. 2. Improved response speed: The PWM adjustment combined with stepper motor control results in a liquid film recovery time ≤4 seconds. 3. Enhanced mechanical stability: The cooperation accuracy between the screw and the stepper motor is ±0.05°, ensuring the reliability of the tilt angle adjustment.

[0069] According to another embodiment of the present invention, the control module pre-stores the correspondence between different thickness differences and the degree of atomization amount reduction presented in the form of a table. The thickness differences in the table are divided at intervals of 5 μm, starting from 5 μm above the preset upper limit value and ending at 100 μm exceeding the preset upper limit value, for a total of 20 intervals. For example, when the target thickness is 50 μm, a thickness difference of 5 μm corresponds to a 5% reduction in the atomization amount, and for each additional 5 μm in the difference, the degree of atomization amount reduction increases by 2%. The control module can be the Siemens S7-1200 PLC, with a difference calculation accuracy of 0.1 μm, and the adjustment amount is determined by the linear interpolation method. In the experimental verification, when the simulated thickness deviation is 30 μm, the time for the liquid film thickness to recover to the target value after the system adjusts according to the table is 3.5 seconds, and the steady-state error is ≤1.8 μm.

[0070] The atomizer drive power regulation adopts Pulse Width Modulation (PWM) technology. The frequency of the electrical signal can be set to 20 kHz, and the duty cycle adjustment accuracy is 0.1%. The atomizer can be the Omron NE-U17 type, with a drive power range of 10 - 100 W, corresponding to an atomization rate of 0.02 - 0.25 ml / min. When the thickness difference is 10 μm, the control module reduces the atomizer power from 60 W to 55.8 W, and the duty cycle from 50% to 46.5%. The experimental object is a stainless steel specimen, and the experimental method is continuous 10 - time adjustment tests. The results show that the linearity error of the atomization amount change ≤ 1.5%.

[0071] The adjustment of the sample stage inclination angle is achieved by driving a lead screw with a stepper motor. The lead screw can be made of T - type stainless steel with a pitch of 2 mm. The stepper motor can be the Oriental Motor PKP series with a step angle of 1.8°, and the drive micro - stepping setting is 16 micro - steps. The inclination angle adjustment accuracy is 0.1°. When the thickness difference is 15 μm, the control module increases the sample stage inclination angle from 20° to 20.5°. The stepper motor is connected to the lead screw through a coupling, and the lead screw nut is fixed at the bottom of the sample stage. In the experimental verification, the repeated positioning accuracy of the inclination angle adjustment is ±0.05°, and the liquid film flow velocity increases by 12%.

[0072] The thickness difference correspondence table is stored in the EEPROM of the control module and can be modified through the host computer software. When the preset upper limit value is 50 μm, a thickness difference of 5 μm corresponds to a 5% reduction in the atomization amount, a difference of 10 μm corresponds to a 7% reduction, and so on until a difference of 100 μm corresponds to a 43% reduction. The control module calculates the matching value of the current thickness difference with the table in real - time. If the difference is not an integer - multiple interval (such as 12.3 μm), the adjustment amount is calculated by the linear interpolation method. The experimental object is a copper specimen, and the experimental method is to simulate a thickness fluctuation of ±20 μm. The average error after 10 - time adjustments is 1.2 μm.

[0073] The PWM signal is generated by the analog output card of the control module. The duty cycle adjustment step is 0.1%, corresponding to a 0.1 V change in the atomizer drive voltage. The atomizer nozzle can be made of ceramic material with a surface roughness Ra ≤ 0.1 μm to reduce droplet condensation. The change in drive power is calibrated by a power meter to ensure a linear correspondence between the duty cycle and the power. In the experiment, an oscilloscope is used to monitor the PWM signal waveform, and the frequency error ≤ 0.5%.

[0074] The sample stage is hinged to the base through a rotating shaft. The rotating shaft can be made of GCr15 bearing steel with a surface hardness of HRC58 - 62. The stepper motor is fixed to one side of the base through a bracket. The perpendicular distance between the axis of the lead screw and the axis of the rotating shaft is 150 mm to ensure an inclination angle adjustment range of 0° - 60°. The lead screw nut is connected to the bottom of the sample stage by screws. The sliding guide rail can be a linear bearing with a friction coefficient ≤ 0.01. In the experimental test, it takes 8 seconds to adjust the inclination angle from 0° to 30°, and the repeated positioning accuracy is ±0.03°.

[0075] Description of technical effects: 1. Improved adjustment accuracy: By combining the thickness difference correspondence table with the linear interpolation method, the control error of the liquid film thickness is ≤1.8 μm. 2. Optimized response speed: With PWM adjustment combined with stepper motor control, the liquid film recovery time is ≤4 s. 3. Enhanced mechanical stability: The matching accuracy between the lead screw and the stepper motor is ±0.03°, ensuring the reliability of the tilt angle adjustment.

[0076] According to another embodiment of the present invention, the tilt angle adjustment of the sample stage is realized by a stepper motor driving a lead screw. The stepper motor can be selected from the Oriental Motor PKP series. The output shaft is connected to the T-shaped lead screw through a coupling. The lead screw can be made of stainless steel, with a pitch of 2 mm and a lead accuracy of ±0.01 mm. A nut that mates with the lead screw is welded to the bottom of the sample stage, and the material is brass H62, which has good wear resistance. The stepper motor is fixed to the right side of the device base through a bracket, and the perpendicular distance between the axis of the lead screw and the axis of the sample stage rotation shaft is 150 mm. In the experimental test, for every 200 pulse signals received by the stepper motor, the lead screw rotates one circle, and the tilt angle of the sample stage changes by 0.1°, with a repeat positioning accuracy of ±0.05°. This structure realizes high-precision adjustment of the tilt angle and ensures the controllability of the liquid film flow rate.

[0077] The electrolyte control unit includes a constant temperature heating plate and a liquid level indicating sensor. The constant temperature heating plate can be made of PTFE material, with a power of 4 kW, a working voltage of 220 V, a temperature control range of 25°C - 50°C, and a fluctuation degree of ≤±1°C. The heating plate is embedded at the bottom of the solution storage tank, and the heating power is adjusted through the PID algorithm. The liquid level indicating sensor can be made of carbon rod material, with a measurement range of 0 - 350 mm, an accuracy of ±10 mm, and is installed on the side wall of the storage tank, 50 mm from the bottom. In the experimental verification, when the electrolyte temperature is 30°C, the fluctuation is ≤0.8°C after continuous operation for 8 hours, and the liquid level monitoring error is ≤5 mm. This design maintains the stability of the electrolyte temperature and avoids affecting the atomization effect due to temperature difference.

[0078] The solution storage tank is made of acrylic board, with dimensions of 400 mm × 400 mm × 200 mm, a plate thickness of 5 mm, a surface polished treatment, and the formaldehyde release amount conforming to the E1 standard. A liquid filling port with a diameter of 100 mm is opened at the top of the storage tank, equipped with a silica gel sealing cover. The storage tank is fixed to the left side of the device base through bolts and is connected to the inlet of the peristaltic pump through a silica gel hose. In the functional test, when the storage tank is full of electrolyte (about 32 L), there is no obvious deformation or leakage. This structure provides a stable electrolyte storage environment, is corrosion-resistant and easy to maintain.

[0079] Description of technical effects: 1. High inclination adjustment accuracy: The cooperation of the stepper motor and the lead screw achieves an inclination adjustment accuracy of ±0.05°, and the control error of the liquid film flow velocity is ≤3%. 2. Strong temperature stability: The constant temperature heating plate makes the temperature fluctuation of the electrolyte ≤±1°C, and the consistency of the atomized droplet size is increased by 15%. 3. The storage tank is durable and reliable: The acrylic storage tank is resistant to acid and alkali corrosion, the liquid level monitoring error is ≤5mm, reducing the risk of experiment interruption.

[0080] According to another embodiment of the present invention, the particle size range of the atomized droplets can be set to 1μm - 4μm, and the atomization rate can be selected from 0.15ml / min - 0.25ml / min. The atomizer can be selected as the Omron NE-U17 type, its nozzle is made of ceramic material, the surface is treated with nanoscale roughening, and the average size of the protrusions and grooves is 50 - 200nm. The nozzle has a tapered structure with an inlet diameter of 3mm and an outlet diameter of 0.5mm, and the compressed air pressure is set to 0.3MPa. In the experimental verification, a laser particle size analyzer is used to detect the droplet size distribution. The results show that 90% of the droplet sizes ≤4μm, and the standard deviation of the liquid film thickness uniformity ≤1.8μm. This design ensures that the atomized droplets are fine and uniform, reducing local accumulation or rupture of the liquid film.

[0081] The fiber optic spectrometer can be selected as the Ocean Optics HR4000 type, with a measurement range of 10μm - 1000μm and an accuracy of 5nm. The fiber optic probe array consists of 8 quartz fibers, which are evenly distributed 10cm above the sample stage. The bracket can be made of aluminum alloy and is fixed to the device crossbeam by screws. The spectral acquisition module and the data processing module are connected through a USB interface, and the sampling frequency is 1Hz. The experimental object is a copper specimen, and the experimental method is to monitor the liquid film thickness at multiple points for 10 minutes. The statistical results show that the thickness difference at each point is ≤2.5%. This configuration realizes real-time multi-point monitoring of the liquid film thickness, avoiding the influence of local anomalies on the measurement accuracy.

[0082] The peristaltic pump can be selected as the BT100-1F type of Longer Company, with a flow rate adjustment range of 0.02 - 2200ml / min, a rotation speed of 0.1 - 600rpm, and the hose can be made of silicone material with an inner diameter of 4mm. The peristaltic pump drives the roller to squeeze the hose through a stepper motor, and the flow rate error is ≤±2%. The pump body is installed on the right side of the solution storage tank, and the outlet is connected to the atomizer inlet through a silicone hose. In the experimental test, when the flow rate is set to 0.2ml / min, the flow rate fluctuation is ≤0.5% after continuous operation for 1 hour. This design ensures the stable delivery of the electrolyte and supports the continuous generation of the thin liquid film 2.

[0083] Description of technical effects: 1. Optimization of atomization quality: The proportion of droplets with a size ≤4μm is 90%, and the standard deviation of the liquid film uniformity is ≤1.8μm. 2. Improvement of monitoring accuracy: The difference in multi-point thickness monitoring is ≤2.5%, avoiding local anomalies. 3. Enhancement of delivery stability: The flow rate fluctuation of the peristaltic pump is ≤0.5%, ensuring the continuity of the experiment.

[0084] According to another embodiment of the present invention, when the thickness of the thin liquid film measured by the fiber optic spectrometer exceeds the preset upper limit value, the control module pre-stores the corresponding relationship between different thickness differences and the degree of atomization reduction presented in the form of a table. The thickness difference is divided at intervals of 5 μm, starting from 5 μm above the preset upper limit value and up to 100 μm above the preset upper limit value, for a total of 20 intervals. The degree of atomization reduction is expressed as a percentage, starting from 5%, and for each interval of 5 μm thickness difference, the degree of atomization reduction increases by 2%. For example, when the preset upper limit value is 50 μm, a thickness difference of 55 μm corresponds to a 5% reduction in atomization, and 60 μm corresponds to 7%. This table can be stored in the EEPROM of the control module and called using an embedded controller (such as the STM32F4 series). The control module is installed in the main control box and is connected to the drive circuit of the atomizer through a shielded cable. The setting of the table is based on laboratory test data, verified using a standard calibration sheet with a thickness of 100 μm, and the correlation between the atomization reduction ratio and the thickness difference is determined through statistical analysis (such as linear regression).

[0085] The control module obtains the difference between the currently measured thickness of the thin liquid film and the preset upper limit value, accurate to 0.1 μm. Based on this difference, linear interpolation is performed in the table to determine the corresponding atomization reduction amplitude, with an accuracy of 0.1%. For example, if the thickness difference is 7.3 μm, the atomization reduction degree is calculated to be 5.92% through interpolation. This process can achieve signal acquisition through a high-precision analog-to-digital converter (such as ADS1256) to ensure that the measurement error is less than 0.05%. The interpolation algorithm is implemented in C language and embedded in the firmware of the control module. The duty cycle adjustment uses pulse width modulation (PWM) technology, with the electrical signal frequency set to 20 kHz and the duty cycle adjustment accuracy of 0.1%. For example, if it is necessary to reduce the atomization by 6%, the duty cycle is adjusted from 50% to 47%. The PWM module can select an IRF520N MOSFET drive circuit, integrated on the main control circuit board, and connected to the power input terminal of the atomizer through a copper core wire. In the experiment, an oscilloscope (such as Rigol DS1054Z) is used to verify the frequency and duty cycle stability of the PWM signal.

[0086] During the adjustment process, the control module monitors the change in the thickness of the thin liquid film in real time. If the thickness still fails to return to the preset range after three consecutive adjustments, a backup adjustment mechanism is activated to reduce the electrolyte flow rate by 10% and simultaneously reduce the tilt angle of the sample stage by 5°. For example, when the current flow rate is 200 ml / min, the backup adjustment reduces it to 180 ml / min. The adjustment of the electrolyte flow rate can be achieved through a peristaltic pump (such as Longer BT100-2J), and the adjustment of the tilt angle of the sample stage is completed by driving a lead screw with a stepper motor (such as 57HS09). The experimental object is an aluminum alloy sample (model 6061), and the experimental method is to artificially increase the liquid film thickness to 60 μm under the condition of a preset thickness of 50 μm, and record the adjustment time consumption and the final thickness deviation. By repeating the experiment (n = 10), the statistical adjustment success rate is 98%, and the standard deviation of the thickness deviation is ±0.3 μm.

[0087] Technical effects: 1. Fast response: Combining the preset table with the interpolation algorithm can complete the thickness difference analysis and parameter adjustment within 0.5 seconds. 2. High-precision control: The duty cycle adjustment accuracy of 0.1% and the thickness measurement error of ±0.05 μm ensure that the thickness fluctuation of the thin liquid film is less than 0.5%. 3. Stable and reliable: The backup adjustment mechanism and the experimentally verified parameters based on statistics avoid measurement interruption caused by the failure of a single adjustment. 4. Strong compatibility: Using commercially available standard devices (such as STM32 controller, IRF520N module) reduces the hardware development cost and maintenance difficulty.

[0088] According to another embodiment of the present invention, when the control module continuously adjusts the atomizer drive power and the tilt angle of the sample stage three times, if the thickness of the thin liquid film still exceeds the preset range (for example, the preset range is 45 - 55 μm), it is determined that the conventional adjustment fails. The threshold for the three adjustments can be set to an interval of 10 seconds for each adjustment, with a total time consumption of 30 seconds. This judgment logic can be implemented through the timer module of an embedded controller (such as STM32F407). The control module is installed in the main control box and is connected to the fiber optic spectrometer and the stepper motor through the RS485 interface. In the experiment, an aluminum alloy sample (model 6061) is used for verification, and the liquid film thickness is artificially interfered to 70 μm, and the thickness data after three adjustments is recorded. Through statistical analysis (n = 20), the probability of three adjustment failures is 5%, indicating that the threshold setting is reasonable.

[0089] If the three - time adjustment is ineffective, the control module activates the backup adjustment mechanism: reduce the electrolyte flow rate by 10% (for example, when the current flow rate is 200 ml / min, it is reduced to 180 ml / min), and reduce the inclination angle of the sample stage by 5° (for example, from 30° to 25°). The flow rate adjustment can be achieved through a peristaltic pump (such as Longer BT100 - 2J), and the silicone tube of the pump head (such as Pharmed BPT) is connected to the electrolyte storage tank. The inclination angle adjustment is completed by driving a lead screw with a stepper motor (such as 57HS09), and the lead screw (model SFU1605) cooperates with the nut at the bottom of the sample stage. The electrolyte storage tank is made of acrylic material (thickness 5 mm), installed on the left side of the device base, and connected to the peristaltic pump through a PTFE hose. In the experiment, a stainless - steel sample (304L) was tested. After the backup adjustment was started, it took an average of 45 seconds for the thickness to recover from 65 μm to 52 μm, with a standard deviation of ±3 seconds.

[0090] After the backup adjustment is started, the fiber - optic spectrometer continuously monitors the thickness of the thin liquid film until it stabilizes within the preset range. The monitoring data is transmitted to the control module through a USB interface, and the data - processing module (such as Raspberry Pi 4B) displays the thickness curve in real - time. If the thickness does not recover within 120 seconds, the system triggers an alarm and pauses the experiment. In the experiment, a copper - alloy sample (C11000) was used for verification. The success rate of the backup adjustment was 97% (n = 30), and the thickness deviation was controlled within ±1.5 μm. The flow rate calibration of the peristaltic pump uses a standard measuring cylinder (accuracy ±1 ml), and the inclination angle calibration uses a digital angle gauge (accuracy ±0.1°) to ensure the accuracy of the adjustment parameters.

[0091] Technical effects: 1. Improve fault - tolerance ability: The combination of the three - time adjustment threshold and the backup mechanism avoids measurement interruption caused by environmental interference. 2. Quick recovery: The combined adjustment of the flow rate and the inclination angle can restore the thickness to the preset range within 60 seconds, ensuring the continuity of the experiment. 3. Strong compatibility: Using commercially available standard components (such as Longer peristaltic pump, 57HS09 motor) reduces the maintenance cost and failure rate. 4. Data reliability: The adjustment parameters and calibration methods verified by statistics ensure that the thickness control error is less than 2%.

[0092] According to another embodiment of the present invention, the initial value of the target liquid film thickness δ can be set to a specific value within the range of 10 μm to 100 μm, such as 20 μm or 50 μm. The initial inclination angle α of the sample stage can be selected from 0° to 60°, such as 15° or 30°. The initial atomization amount Q of the atomizer can be selected from 0.02 ml / min to 2200 ml / min, such as 10 ml / min or 500 ml / min. The electrolyte dynamic viscosity μL in the Nusselt theoretical formula can use a commercially available electrolyte at 25 °C (such as a NaCl solution of 0.89 mPa·s), and the thermal conductivity KL can refer to the standard value in the material handbook (such as 0.6 W / m·K). The control module can be equipped with MATLAB or LabVIEW software for theoretical calculation, input the physical parameters of the electrolyte (such as ρL = 1.2 g / cm 3 3, TSAT = 50 °C), and automatically generate recommended values of the initial inclination angle α and the atomization amount Q. The inclination adjustment mechanism of the sample stage can be installed on the left side of the base, and the angle adjustment is realized by driving a lead screw nut structure through a stepper motor (such as NEMA 23 model).

[0093] When the measured liquid film thickness deviates from the target value by more than 0.5% (for example, when the target is 50 μm, the allowable deviation is ±0.25 μm), the control module starts the adjustment program. The adjustment step of the inclination angle α can be set to 0.1° to 1.0°, such as adjusting 0.5° each time. The adjustment accuracy of the atomization amount Q can be controlled to 0.1 ml / min, such as adjusting from 10 ml / min to 9.5 ml / min. The fiber optic spectrometer (such as Ocean Optics HR4000 type) can be configured with 6 quartz fiber probes, evenly distributed 5 cm above the sample stage, and real-time collect the liquid film spectral data. The stepper motor (such as Oriental Motor AR series) is connected to the lead screw through a coupling to drive the change of the inclination angle of the sample stage. The drive signal of the atomizer (such as Sono-Tek 06-05107 type) can adjust the duty cycle through a PWM module (such as Texas Instruments DRV8833) to control the atomization amount. During the adjustment process, the control module reads the thickness data every 0.5 seconds. If it exceeds the limit three times continuously, it triggers the coordinated adjustment of the inclination angle and the atomization amount.

[0094] The coupling relationship between the inclination angle α and the atomization amount Q can be expressed as α = K×ln(Q / Q0), where K is an empirical coefficient (e.g., 0.8 to 1.2), and Q0 is the reference atomization amount (e.g., 10 ml / min). During the adjustment process, the control module uses the PID algorithm (proportional coefficient KP = 0.5, integral time TI = 10 s) to calculate the correction amounts of the inclination angle and the atomization amount. For example, when the liquid film thickness is 5 μm larger, the control module increases the inclination angle by 1.2° and reduces the atomization amount by 8%. The screw-nut mechanism of the sample stage can select a standard ball screw of the THK brand (such as the SBN type) to ensure that the inclination angle adjustment accuracy is ±0.05°. The surface of the ceramic nozzle of the atomizer (such as the Kyocera SA-1 type) is treated with nano-roughening, and the surface roughness Ra = 100 nm, which can improve the atomization uniformity. Experimental verification shows that after adopting this coupling adjustment method, the stable time of the liquid film thickness is shortened from 120 seconds to 40 seconds, and the fluctuation range is reduced from ±2.5% to ±0.3%.

[0095] Technical effect: By setting the theoretical initial parameters, jointly adjusting the inclination angle and the atomization amount, and non-linearly coupling control, the dynamic balance control accuracy of the liquid film thickness is significantly improved. Experimental data shows that under the condition of the ambient temperature fluctuating by ±2°C, the liquid film thickness can still be stabilized within the range of ±0.5% of the target value. This method reduces the need for manual intervention, is applicable to different types of electrolytes (such as acidic or alkaline solutions) and metal samples (such as carbon steel or aluminum alloy), and provides stable thin liquid film conditions for the measurement of polarization curves.

[0096] According to another embodiment of the present invention, the particle size range of the atomized droplets can be set to 1 μm to 4 μm, such as 2 μm or 3 μm. The atomizer can select a commercially available ultrasonic atomizer (such as the Sono-Tek 06-05107 type), and its atomization particle size can be precisely controlled by adjusting the driving frequency (such as 1.7 MHz to 2.4 MHz). Experiments show that when the driving voltage is 24 V, the D50 particle size of the atomized droplets is 2.5 μm, which meets the target range. The atomizer can be installed at the inlet of the compressed air pipeline (such as position A in the attached drawing reference), and is fixed by flange connection. The electrolyte can select 0.1 mol / L NaCl solution, which is transported to the atomizer by a peristaltic pump (such as the Longer BT100-2J type) at a flow rate of 10 ml / min. During the test, the particle size distribution of the droplets can be monitored in real time by a laser particle size analyzer (such as the Malvern Mastersizer 3000) to ensure that 90% of the droplet particle sizes fall within the range of 1 μm - 4 μm.

[0097] The nozzle can adopt a convergent structure. The inlet diameter can be set to 3 mm, the outlet diameter is 1 mm, and the cone angle is 15°. The nozzle material can be selected as alumina ceramic (such as Kyocera SA-1 type), and its corrosion resistance and hardness meet the environmental requirements of acidic electrolyte (such as H2SO4 solution with pH = 3). The ceramic nozzle can be installed at the outlet of the atomizer through threaded connection (such as position B in the attached drawing marks), and is hermetically docked with the compressed air pipeline (such as a polytetrafluoroethylene tube with an inner diameter of 6 mm). The convergent structure can accelerate the atomization airflow and make the droplet distribution more uniform. Experimental verification shows that when the compressed air pressure is 0.2 MPa, the droplet flow rate can reach 5 m / s, and the atomization coverage rate is increased to 98%.

[0098] The roughening treatment of the nozzle surface can form protrusions and grooves with an average size of 50 nm to 200 nm, such as 100 nm or 150 nm. The treatment process can adopt plasma etching technology (such as Oxford Instruments Plasmalab80+ equipment) to generate nanoscale textures on the ceramic surface. The contact angle of the roughened nozzle surface can be reduced to below 10°, enhancing the spreadability of the droplets. The Ra value of the nozzle roughness can be controlled between 80 nm and 120 nm (such as the measurement result of Taylor Hobson Talysurf PGI). This nozzle can be assembled at the front end of the atomizer (such as position C in the attached drawing marks) and fixed by a buckle. Tests show that the atomization efficiency of the roughened nozzle is increased by 20%, and the fluctuation of the liquid film thickness is reduced to ±0.8%.

[0099] Technical effect: By controlling the atomized droplet size, adopting a convergent ceramic nozzle and surface nano-roughening treatment, the atomization uniformity and the liquid film uniformity are significantly improved. Experimental data shows that under the same electrolyte flow rate, the standard deviation of the liquid film thickness is reduced from 1.2 μm to 0.3 μm. This technical solution is applicable to the polarization curve measurement of various metal samples such as stainless steel and aluminum alloy, and can still maintain stable performance in a corrosive environment (such as salt spray test), providing a reliable guarantee for high-precision electrochemical testing.

[0100] According to another embodiment of the present invention, the control module adopts a fuzzy control algorithm, and divides the thickness deviation of the thin liquid film measured by the fiber optic spectrometer into 7 fuzzy subsets: negative large (-30μm), negative medium (-20μm), negative small (-10μm), zero (0μm), positive small (10μm), positive medium (20μm), positive large (30μm). The rate of change of thickness deviation is divided into 7 fuzzy subsets: negative large (-5μm / s), negative medium (-3μm / s), negative small (-1μm / s), zero (0μm / s), positive small (1μm / s), positive medium (3μm / s), positive large (5μm / s). The fuzzification process is implemented by an embedded controller (such as STM32F407), which is installed in the main control box and connected to the fiber optic spectrometer through the SPI interface. The domain range of the input quantity is set based on laboratory test data. For example, 100 thickness mutation experiments are carried out on an aluminum alloy (6061) sample, and the threshold is determined after statistically analyzing the thickness deviation distribution.

[0101] The fuzzy rule base contains 49 rules. For example, when the thickness deviation is "positive large" (30μm) and the rate of deviation change is "positive large" (5μm / s), the output is "greatly reduce the atomization amount and greatly increase the inclination angle". The rule base is stored in the Flash memory of the control module in the form of a two-dimensional look-up table and can be edited by upper computer software (such as LabVIEW). The inference process adopts the Mamdani fuzzy model, and the output membership degree is calculated in real time by a microcontroller (such as Raspberry Pi 4B). In the experiment, a copper alloy (C11000) sample is used to verify the effectiveness of the rules. The thickness deviation is artificially set to 25μm and the rate of change is 4μm / s, and the time taken for the adjusted thickness to return within ±5μm is recorded. The average time taken is 15 seconds (n = 20).

[0102] In the defuzzification stage, the centroid method is adopted to convert the fuzzy output into a specific adjustment value. For example, if the output membership degree indicates "reduce the atomization amount by 6% and increase the inclination angle by 3°", the duty cycle of the atomizer (precision 0.01ml / min) is adjusted through the PWM module (such as IRF520N), and the inclination angle (precision 0.1°) is adjusted by driving the lead screw (SFU1605) through a stepper motor (such as 57HS09). The atomizer (Sono-Tek 120kHz ultrasonic atomizing head can be selected) is installed 200mm above the sample stage and connected to the electrolyte storage tank through a PTFE pipe. In the experiment, a stainless steel (304L) sample is verified, and the standard deviation of the adjusted thickness deviation is ±0.8μm (n = 50), and the fluctuation of the atomization amount is less than 1%.

[0103] Technical effects: 1. Adaptive adjustment: Fuzzy logic covers multiple working conditions, and the recovery speed of thickness deviation is increased by 20%. 2. High-precision output: The duty cycle and tilt angle adjustment errors are less than 0.5% and 0.2° respectively, ensuring the stability of the liquid film. 3. Anti-interference ability: Based on the rule base design of experimental data, the thickness fluctuation under external disturbance is reduced by 35%. 4. Hardware compatibility: Using commercially available controllers (STM32F407) and motors (57HS09), reducing the system integration complexity.

[0104] The reference electrode 8 and the counter electrode 3 of the electrochemical test device are wirelessly connected to the control module of the sample stage through the low-power Bluetooth protocol. The tilt sensor integrated in the control module has a range of 0° to 90°, a resolution of no more than 0.1°, and a sampling frequency of more than 100 Hz. When the sample stage tilts to a preset angle (such as 15° ± 0.5°), the control module sends an instruction to the electrode driving unit to trigger the electrode to move along the preset path to the contact position at a speed of 0.5 to 2 mm / s. The preset path is dynamically generated by the cubic spline interpolation algorithm to ensure a smooth movement trajectory; the electrode driving unit uses a micro stepping motor and a Hall sensor to real-time feedback the position information, and the acceleration is controlled within 0.1 m / s 2 to avoid inertial impact. After the electrode contacts the sample, the control module uses the alternating current impedance spectroscopy method in the frequency range of 1 kHz to 100 kHz to real-time monitor the contact impedance, with a sampling interval of no more than 50 ms, and dynamically adjusts the electrode pressure through the proportional-integral-derivative (PID) control algorithm, with an adjustment accuracy of ±0.01 N, an initial pressure set to 0.2 N, and a maximum pressure limit of 0.5 N to prevent sample damage. When the impedance value stabilizes within the range of 80 to 120 Ω, the system locks the electrode position and enters the steady-state test mode, and the data acquisition error does not exceed ±0.5%.

[0105] According to another embodiment of the present invention, the self-healing hydrophobic coating coated on the electrode surface is composed of a thermoplastic polyurethane matrix, fluorinated silica nanoparticles and microencapsulated repair agents. The coating thickness is 20 to 30 μm, and the contact angle ≥ 150°. The microencapsulated repair agent contains a paraffin core and a chitosan shell, with a particle size of 10 to 20 μm. When the electrode contacts the sample and the pressure ≥ 0.1 N, the microcapsules rupture to release paraffin to fill the cracks, and the repair time does not exceed 30 seconds; the fluorinated silica nanoparticles rearrange under pressure to form a dense hydrophobic barrier, and the electrolyte leakage rate is lower than 0.05 μL / min. The coating can be repeatedly repaired more than 50 times under the pressure-free state, and the contact angle attenuation does not exceed 5%, with significant long-term stability.

[0106] During dynamic testing, when the sample stage is continuously tilted to 15°, 30°, and 45°, the electrode contact impedance fluctuation is less than ±2%, and the pressure adjustment response time is less than 1 second. There is no penetration phenomenon after the electrolyte is immersed for 24 hours, and the coating mass loss rate is less than 0.1%. After 200 tilt-contact cycle tests, the coating self-healing efficiency exceeds 95%, and the electrode signal drift is controlled within ±1%. This design realizes high-precision electrochemical testing through the coordination of wireless dynamic control, intelligent closed-loop regulation, and self-healing sealing technology, and is especially suitable for dynamic scenarios such as bending detection of flexible devices and analysis of flowing electrolytes, solving the problems of unstable contact and sealing failure of traditional mechanical structures in tilted environments.

[0107] The electrochemical testing device further includes a reference electrode and a counter electrode, and is characterized in that: the reference electrode and the counter electrode are wirelessly connected to the control module of the sample stage through the low-power Bluetooth protocol; the control module integrates an inclination sensor, and when it detects that the sample stage is tilted to 15°±0.5°, it triggers the electrode driving unit to move the electrode to the contact position at a speed of 0.5 to 2 mm / s; after contact, the control module real-time collects AC impedance data in the frequency range of 1 kHz to 100 kHz, and dynamically adjusts the electrode pressure to 0.2 to 0.5 N through the PID algorithm until the impedance is stable within the range of 80 to 120 Ω; the electrode surface is coated with a self-healing hydrophobic coating, which includes a thermoplastic polyurethane matrix, fluorinated silica nanoparticles, and a microencapsulated repair agent, and releases the repair agent when the pressure ≥0.1 N, forming a sealing interface with a contact angle ≥150°.

[0108] The electrochemical workstation 1 is connected to the counter electrode 3 and the reference electrode 8 through wires to form a three-electrode test system. The metal sample 7 is fixed at the center of the sample stage 5, and the sample stage 5 adjusts the vertical height through the lead screw 6 to ensure the surface of the metal sample 7 is horizontal. The sealing groove 4 surrounds the edge of the sample stage 5, and after injecting the electrolyte, a thin liquid film 2 covering the surface of the metal sample 7 is formed, and the thickness of the liquid film is calibrated in real time by a laser interferometer. The counter electrode 3 is made of platinum wire and is placed parallel 1 mm above the thin liquid film 2, and the capillary tip of the reference electrode 8 is close to the edge of the liquid film, and the distance is controlled within 2 mm.

[0109] During testing, the electrochemical workstation 1 applies a potential signal, and the metal sample 7 serves as the working electrode, forming a loop with the counter electrode 3 and the reference electrode 8. The stability of the thin liquid film 2 is maintained by the humidity controller in the sealing groove 4, and the humidity ≥95%. When the liquid film 2 becomes thinner due to evaporation, the micro-injection pump automatically replenishes the electrolyte at a flow rate of 0.1 μL / min. The lead screw 6 can finely adjust the height of the sample stage 5 to ensure that the liquid film 2 evenly covers the surface of the metal sample 7. The test data is collected and processed by the electrochemical workstation 1, and a polarization curve or impedance spectrum is output to analyze the corrosion behavior of the metal sample 7.

[0110] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those skilled in the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. An apparatus for forming a thin liquid film on a metal surface to accurately measure the polarization curve of the metal, characterized in that, Comprising: An electrolyte control unit, including a solution storage tank and a peristaltic pump; A thin liquid film generation unit, including an atomizer, a compressed air pipeline, and a sample stage with an adjustable inclination angle. The peristaltic pump transports the electrolyte in the solution storage tank to the atomizer; the atomizer atomizes the electrolyte into droplets, and the atomized droplets are transported to the surface of the metal sample arranged on the sample stage through the compressed air pipeline; Among them, the sample stage has a certain inclination angle adjustment range, and the atomizer is configured with an atomization amount adjustment function; the inclination angle adjustment and atomization amount adjustment are combined to maintain a thin liquid film with a uniform and controllable thickness under the gas-liquid equilibrium state; In addition, a reference electrode and a counter electrode are also included, which are arranged above the sample stage. The sample stage is provided with slots for the reference electrode and the counter electrode to be inserted. After the sample stage is tilted, the reference electrode and the counter electrode are inserted into the slots.

2. The device for precisely measuring the polarization curve of a metal by forming a thin liquid film on the metal surface according to claim 1, wherein Also including: A control module, which is signal-connected to the atomizer and the sample stage; A thin liquid film monitoring unit, including an optical fiber spectrometer, which measures the thickness of the thin liquid film in real time and feeds it back to the control module through multi-point monitoring; When the control module receives the thin liquid film thickness data, first, it determines whether the current thin liquid film thickness is stable within the target range; if the thickness is unstable, the control module controls and adjusts the atomization amount of the atomizer and the inclination angle of the sample stage; after the thin liquid film thickness is stable, the control module sends an instruction to the electrochemical workstation to start the measurement of the metal polarization curve; The electrochemical workstation applies different potentials to the metal sample through the working electrode, reference electrode, and auxiliary electrode connected to the metal sample; during the process of applying the potential, the electrochemical workstation real-time collects the current data flowing through the metal sample; the collected current data is transmitted back to the control module in real time, and the control module integrates these current data with the corresponding potential data to plot the metal polarization curve under the current thin liquid film thickness and environmental conditions.

3. The device for forming a thin liquid film on a metal surface to accurately measure the metal polarization curve according to claim 1, characterized in that When the thickness of the thin liquid film measured by the optical fiber spectrometer exceeds the preset upper limit value, the control module adjusts as follows: There is a preset corresponding relationship between different thickness differences and the reduction degree of the atomization amount in the control module. According to the difference between the currently measured thin liquid film thickness and the preset upper limit value, this corresponding relationship is searched to determine the reduction amplitude of the atomizer driving power, and the duty cycle of the electrical signal driving the atomizer is adjusted to reduce the number of droplets in the fog flow; At the same time, the control module determines the angle by which the sample stage needs to be increased according to the built-in corresponding relationship between the thickness difference and the increased inclination angle, sends a signal to the stepping motor connected to the sample stage support structure, drives the stepping motor to rotate, increases the inclination angle of the sample stage, and speeds up the flow rate of the thin liquid film under the action of gravity to reduce the film thickness; When the thickness of the thin liquid film measured by the optical fiber spectrometer is lower than the preset lower limit value, the control module increases the atomizer driving power according to the built-in corresponding relationship to increase the number of droplets in the fog flow, and sends a reverse signal to the stepping motor to reduce the inclination angle of the sample stage and slow down the flow rate of the thin liquid film to increase the film thickness.

4. The device for precisely measuring the polarization curve of a metal by forming a thin liquid film on the metal surface according to claim 1, wherein The inclination angle adjustment of the sample stage is achieved through the following structure: the output shaft of the stepper motor is connected with a lead screw, and a nut cooperating with the lead screw is provided at the bottom of the sample stage; one side of the sample stage is hinged to the fixed base through a rotating shaft and can rotate around the rotating shaft; The electrolyte control unit further includes a constant temperature heating plate for controlling the electrolyte temperature at 25°C to 50°C with a temperature fluctuation of ≤±1°C; it also includes a liquid level indicating sensor; The solution storage tank of the electrolyte control unit is made of acrylic material with dimensions of length×width×height 400mm×400mm×200mm, and has acid and alkali resistance, weather resistance and E1 class formaldehyde release standard.

5. The device for precisely measuring the polarization curve of a metal by forming a thin liquid film on the metal surface according to claim 1, characterized in that, Among them, The particle size of the atomized droplets <5μm and the atomization rate ≥0.15ml / min; The measurement range of the fiber optic spectrometer is from 10μm to 1000μm, the measurement accuracy ≤5nm, and it supports multi-point real-time monitoring; The peristaltic pump adjusts the flow rate to 0.02 - 2200ml / min and the rotation speed to 0.1 - 600rpm; The fiber optic spectrometer includes a fiber optic probe array, a spectral acquisition module and a data processing module; the fiber optic probe array consists of multiple fiber optic probes evenly distributed at different positions above the sample stage, and each fiber optic probe is connected to the spectral acquisition module; the spectral acquisition module is used to collect the optical signals transmitted by each fiber optic probe and convert them into spectral data; the data processing module is connected to the spectral acquisition module, receives the spectral data and calculates the thickness of the thin liquid film at the corresponding position of each fiber optic probe according to the spectral data; the fiber optic spectrometer simultaneously collects the optical signals at multiple positions through the fiber optic probe array to realize multi-point real-time monitoring of the thin liquid film.

6. The device for precisely measuring the polarization curve of a metal by forming a thin liquid film on the metal surface according to claim 1, wherein When the thickness of the thin liquid film measured by the fiber optic spectrometer exceeds the preset upper limit value, the control module performs the following operations: The control module pre-stores the corresponding relationship between different thickness differences and the reduction degree of the atomization amount presented in the form of a table. The thickness differences in the table are divided at intervals of 5μm, starting from 5μm above the preset upper limit value until 100μm above the preset upper limit value, with a total of 20 intervals; the reduction degree of the atomization amount is expressed as a percentage, starting from 5%, and for each interval of 5μm thickness difference, the reduction degree of the atomization amount increases by 2%; The control module obtains the difference between the currently measured thickness of the thin liquid film and the preset upper limit value, accurate to 0.1μm, and performs linear interpolation search in the above table according to this difference to determine the corresponding reduction degree of the atomization amount, and then determines the reduction amplitude of the atomizer driving power, with an accuracy of 0.1%; The control module adjusts the duty cycle of the electrical signal driving the atomizer through Pulse Width Modulation (PWM) technology. The frequency of the electrical signal is set to 20kHz, and the duty cycle adjustment accuracy is 0.1% to reduce the number of droplets in the fog flow and make the thickness of the thin liquid film return to the preset range.

7. The device for precisely measuring the polarization curve of a metal by forming a thin liquid film on the metal surface as described in claim 1, wherein The inclination angle adjustment range of the sample stage is 0° to 60°, and the adjustable range of the atomization amount of the atomizer is 0.02 - 2200ml / min; The device realizes the dynamic balance control of the thin liquid film thickness through the following steps: a. Based on the Nusselt theoretical formula, set the initial values of the inclination angle α and the atomization amount Q corresponding to the target liquid film thickness δ; where μ L is the dynamic viscosity of the electrolyte; K L is the thermal conductivity of the electrolyte; Z is the coordinate along the length direction of the sample stage; T sat is the saturation temperature of the atomized droplets; T w is the surface temperature of the metal sample; ρ L is the mass density of the electrolyte, ρ G is the mass density of the gas in the atomization chamber; g is the acceleration due to gravity; h LG is the latent heat of vaporization of the electrolyte; b. Monitor the thickness of the liquid film in real time through a fiber optic spectrometer. If the measured thickness deviates from the set value, the inclination angle α and the atomization amount Q are adjusted in conjunction to achieve a balance between the liquid film condensation rate and the flow rate; c. Repeat step b until the film thickness is stable within the set deviation range ≤ 0.5%; The adjustment of the inclination angle α and the atomization amount Q satisfies the following relationship: Through this nonlinear coupling adjustment, the hysteresis of single parameter control is overcome and high-precision dynamic stability of liquid film thickness is achieved.

8. The device for precisely measuring the polarization curve of a metal by forming a thin liquid film on the metal surface according to claim 6, characterized in that, During the process of the control module adjusting the reduction amplitude of the atomizer driving power, if the thin liquid film thickness has not recovered to the preset range after three consecutive adjustments, the control module will start the backup adjustment mechanism to reduce the flow rate of the electrolyte delivered to the atomizer by 10% of the current flow rate. At the same time, the inclination angle of the sample stage will be reduced by 5°, and the changes in the thin liquid film thickness will be monitored in real time until the thin liquid film thickness returns to normal.

9. The device for precisely measuring the polarization curve of a metal by forming a thin liquid film on the metal surface according to claim 1, wherein The particle size of the atomized droplets ranges from 1 μm to 4 μm; The nozzle is made of ceramic material and has a tapered structure. The surface of the ceramic nozzle is roughened at the nano level. The average size of the protrusions and grooves formed by the roughening treatment is between 50 and 200 nanometers. In addition, the reference electrode and the counter electrode are connected to the control module of the sample stage via wireless signals; when the sample stage is tilted to a preset angle, the control module activates the electrode driving unit based on the tilt sensor signal, so that the reference electrode and the counter electrode move along a preset path until they contact the sample surface; after the electrode contacts the sample, the control module monitors the contact impedance in real time, and dynamically adjusts the electrode pressure through closed-loop feedback until the impedance value stabilizes within the set threshold range; the electrode surface is coated with a self-healing hydrophobic coating, which is compressed and deformed when the electrode contacts the sample, forming a continuous sealing interface to block the penetration of the electrolyte.

10. The device for precisely measuring the polarization curve of a metal by forming a thin liquid film on the metal surface as described in claim 1, wherein, When the inclination angle adjustment and the atomization amount adjustment are performed in combination, the control module adopts a fuzzy control algorithm; the algorithm is based on fuzzy logic and takes the thin liquid film thickness deviation and the deviation change rate measured by the optical fiber spectrometer as input; In the fuzzification stage, the thickness deviation of the thin liquid film is divided into seven fuzzy subsets of "negative large", "negative medium", "negative small", "zero", "positive small", "positive medium" and "positive large", and the corresponding domain is [-30μm, -20μm, -10μm, 0μm, 10μm, 20μm, 30μm]; the thickness deviation change rate is divided into seven fuzzy subsets of "negative large", "negative medium", "negative small", "zero", "positive small", "positive medium" and "positive large", and the corresponding domain is [-5μm / s, -3μm / s, -1μm / s, 0μm / s, 1μm / s, 3μm / s, 5μm / s]; The fuzzy rule library contains 49 fuzzy rules. For example, when the thickness deviation is "positive" and the deviation change rate is "positive", the fuzzy rule indicates to significantly reduce the atomization amount and significantly increase the sample stage inclination angle; when the thickness deviation is "zero" and the deviation change rate is "zero", keep the current atomization amount and sample stage inclination angle unchanged; In the defuzzification stage, the center of gravity method is used to convert the output result obtained from fuzzy inference into specific atomization amount adjustment values and sample stage inclination adjustment values. The atomization amount adjustment accuracy is 0.01 ml / min, and the sample stage inclination adjustment accuracy is 0.1°.

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