An electrochemical measurement device for atmospheric corrosion of metallic materials under alternating current interference

Abstract

This invention relates to the field of metal corrosion detection technology, and discloses an electrochemical measurement device for atmospheric corrosion of metal materials under AC interference. The device includes a temperature and humidity control system, an external AC circuit, and an electrochemical testing system. The temperature and humidity control system includes a cavity, a plastic sleeve, matching test pieces, an electrochemical workstation, a constant temperature circulating water bath, an ultrasonic nebulizer, and a constant temperature water bath. The external AC circuit includes an AC power supply, an adjustable resistor, a data acquisition board, a capacitor, and an ammeter. This electrochemical measurement device for atmospheric corrosion of metal materials under AC interference can generate and control the formation and maintenance of a liquid film through the temperature and humidity control system. By setting up the external AC circuit and inductor, the AC power can be effectively separated from the electrochemical measurement device, thereby realizing the electrochemical measurement of atmospheric corrosion of metal materials under AC interference.

Description

Technical Field

[0001] This invention relates to the field of metal corrosion detection technology, specifically to an electrochemical measurement device for atmospheric corrosion of metal materials under alternating current interference. Background Technology

[0002] Electrochemical corrosion of metallic materials under alternating current (AC) occurs within an external electric field. This applied electric field is much stronger than the internal electric field in the natural polarization process, and the magnitude and direction of the AC current are constantly changing. Under the influence of this constantly changing and strong AC electric field, the electrochemical mechanism of metallic materials undergoes significant alterations. The difficulty in avoiding mutual interference between the AC current and the electrochemical testing system, coupled with the challenges in achieving and controlling the formation of thin liquid films, has hindered the development of electrochemical measurement methods for atmospheric corrosion of metallic materials under AC interference.

[0003] Atmospheric corrosion is ultimately corrosion under thin liquid films. Current research on the electrochemical properties of metals under thin liquid films mainly focuses on steady-state or dynamic liquid film conditions. Dynamic liquid films are generally achieved through alternating wet and dry processes. Research on the control of static thin liquid films mainly focuses on three aspects: liquid film formation, thickness measurement, and thickness control. The liquid film is mainly formed through three methods: wetting, evaporation, and salt deliquescence. For the thickness of thin liquid films, high-precision equipment such as Filmetrics F20-NIR (100nm-250um) is used for measurement. However, these laser instruments mostly require parameters such as the liquid refractive index, which change with the liquid composition and are difficult to obtain. Therefore, the current method for measuring liquid film thickness mainly uses a micrometer screw gauge to control an extremely fine platinum needle in conjunction with a zero-resistance ammeter for mechanical measurement. This method is simple, practical, inexpensive, and the error is within an acceptable range. Current domestic and international research on liquid film thickness control includes controlling relative humidity through saturated salt solutions to suppress liquid film evaporation. However, this method has the disadvantages of being relatively slow to control, and the saturation of salt varies at different temperatures, resulting in different relative humidity levels above the solution. This presents significant drawbacks, such as high operational difficulty and difficulty in achieving precise control. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an electrochemical measurement device for atmospheric corrosion of metallic materials under alternating current interference. This device features the ability to generate and control the formation and maintenance of a liquid film, and can effectively separate the alternating current from the electrochemical measurement device, thereby achieving the advantages of electrochemical measurement of atmospheric corrosion of metallic materials under alternating current interference and solving the problems mentioned in the background art.

[0005] This invention provides the following technical solution: an electrochemical measurement device for atmospheric corrosion of metallic materials under alternating current interference, comprising:

[0006] A temperature and humidity control system includes a cavity, a plastic sleeve, matching test pieces, an electrochemical workstation, a constant temperature circulating water bath, an ultrasonic nebulizer, and a constant temperature water bath. The plastic sleeve is located at the center of the bottom of the cavity, and the matching test pieces are located at the center of the bottom of the plastic sleeve. The matching test pieces include a PVC pipe, epoxy resin, material samples, a carbon rod, and a reference electrode. The inner cavity of the plastic sleeve is filled with an electrolyte. A thermometer and hygrometer are located on one side of the top of the cavity, and a micrometer is located at the center of the top of the cavity. A constant temperature water bath is located on one side of the cavity. A constant temperature circulating water bath is provided. The outlet of the constant temperature circulating water bath is connected to one side of the top of the inner cavity of a plastic sleeve through an outlet pipe. The bottom of the inner cavity of the plastic sleeve is connected to the constant temperature circulating water bath through a return pipe. An ultrasonic atomizer and a constant temperature water bath are provided on the other side of the cavity. A moisture pipe is provided in the inner cavity of the constant temperature water bath. One end of the moisture pipe is connected to the gas outlet of the ultrasonic atomizer. The other end of the moisture pipe passes through the side wall at the bottom of the cavity and extends into the inner cavity of the cavity. A moisture outlet is provided at the top of the other side of the inner cavity of the cavity. A moisture flow control valve is provided at the other end of the moisture pipe.

[0007] An external AC circuit is provided, comprising an AC power supply, an adjustable resistor, a data acquisition board, a capacitor, and an ammeter. The adjustable resistor is connected to the AC power supply and the data acquisition board via wires. The ammeter is connected to the capacitor and the carbon rod via wires. The capacitor is connected to the AC power supply via wires. The carbon rod is connected to the data acquisition board via wires. The material sample is connected to the adjustable resistor via wires.

[0008] An electrochemical testing system includes an electrochemical workstation, an inductor, and two counter electrodes located in an electrolyte. The two counter electrodes and a reference electrode are connected to the electrochemical workstation via wires. The electrochemical workstation is connected to one end of the inductor, and the other end of the inductor is connected to a wire connecting a material sample.

[0009] Preferably, the portion of the humidifier tube located inside the constant temperature water bath is spiral-shaped.

[0010] Preferably, the manufacturing steps of the matching test piece are as follows: the metal material is cut into a material sample with a cross-section of 10×10mm. Except for one 10×10mm surface exposed as the working surface, the other surfaces are encapsulated in a PVC tube with epoxy resin. The back of the working surface is connected to the wire. A 1mm hole is drilled in the matching test piece. The hole is filled with saturated KCl agar. A U-shaped tube filled with saturated KCl solution is connected to the bottom of the matching test piece as a salt bridge. One end of the U-shaped tube is connected to the hole. The other end of the U-shaped tube is provided with a reference electrode. The carbon rod and the hole are symmetrically distributed on both sides of the material sample, and are also 1mm apart from the material sample.

[0011] Preferably, the electrolyte level is higher than the height of the test specimen.

[0012] Preferably, the plastic sleeve is made of thermally conductive plastic.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. This electrochemical measurement device for atmospheric corrosion of metallic materials under AC interference covers the construction method of the device and the fabrication method of the supporting test pieces. It can realize the electrochemical measurement of atmospheric corrosion of metallic materials under AC interference. The liquid film thickness can be generated and controlled to a minimum of 10 μm by adding appropriate nonionic surfactants. The magnitude of AC intensity is related to the capacitance and inductance of the AC application circuit. If the AC intensity increases, the inductance needs to be increased appropriately.

[0015] 2. This electrochemical measurement device for atmospheric corrosion of metallic materials under AC interference can generate and control the formation and maintenance of liquid film through a temperature and humidity control system. By setting up an external AC circuit and an inductor, the AC current can be effectively separated from the electrochemical measurement device, thereby realizing the electrochemical measurement of atmospheric corrosion of metallic materials under AC interference. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the device setup for the present invention;

[0017] Figure 2 This is a schematic diagram of the test specimen for the structure of this invention;

[0018] Figure 3 This is a cross-sectional schematic diagram of the test specimen used to support the structure of this invention.

[0019] In the diagram: 1. Cavity; 2. Plastic sleeve; 4. Matching test piece; 5. Counter electrode; 6. Electrochemical workstation; 8. Thermometer and hygrometer; 9. Micrometer; 10. Water outlet pipe; 11. Moisture outlet; 12. Return pipe; 13. Constant temperature circulating water bath; 14. Ultrasonic nebulizer; 15. Moisture pipe; 16. Constant temperature water bath; 17. Moisture flow control valve; 18. AC power supply; 19. Adjustable resistor; 20. Data acquisition board; 21. Capacitor; 22. Ammeter; 23. Inductor; 41. PVC pipe; 42. Epoxy resin; 43. Material sample; 44. Carbon rod; 45. Orifice; 46. U-tube; 47. Reference electrode. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figures 1 to 3An electrochemical measurement device for atmospheric corrosion of metallic materials under alternating current interference includes a temperature and humidity control system, an external AC circuit, and an electrochemical testing system. The temperature and humidity control system includes a cavity 1, a plastic sleeve 2, a matching test piece 4, an electrochemical workstation 6, a constant temperature circulating water bath 13, an ultrasonic nebulizer 14, and a constant temperature water bath 16. The plastic sleeve 2, made of thermally conductive plastic, is located in the middle of the bottom of the cavity 1. The matching test piece 4 includes a PVC pipe 41, epoxy resin 42, a material sample 43, a carbon rod 44, and a reference electrode 47. The cavity of the plastic sleeve 2 is filled with an electrolyte, the electrolyte level being higher than the height of the matching test piece 4. A thermometer and hygrometer 8 is located on one side of the top of the cavity 1, and a micrometer 9 is located in the middle of the top of the cavity 1. The micrometer 9 allows for slow adjustment of the liquid film thickness and repeated thickness measurements until the liquid film thickness reaches the predetermined value. A constant temperature circulating water bath 13 is provided on one side of the cavity 1. The outlet of the constant temperature circulating water bath 13 is connected to one side of the top of the inner cavity of the plastic sleeve 2 through the outlet pipe 10. The bottom of the inner cavity of the plastic sleeve 2 is connected to the constant temperature circulating water bath 13 through the return pipe 12. The constant temperature circulating water bath 13 and the plastic sleeve 2 are arranged to ensure the temperature of the device. An ultrasonic nebulizer 14 and a constant temperature water bath 16 are provided on the other side of the cavity 1. The inner cavity of the constant temperature water bath 16 is equipped with a humidification pipe 1. 5. The portion of the humidifier tube 15 located inside the constant temperature water bath 16 is spiral-shaped. One end of the humidifier tube 15 is connected to the gas outlet of the ultrasonic nebulizer 14, and the other end of the humidifier tube 15 passes through the side wall at the bottom of the cavity 1 and extends into the inner cavity of the cavity 1. A humidifier outlet 11 is provided at the top of the other side of the inner cavity of the cavity 1, and a humidifier flow control valve 17 is provided at the other end of the humidifier tube 15. The flow rate of the hot steam after constant temperature heating can be controlled by setting the humidifier flow control valve 17.The external AC circuit includes an AC power supply 18, an adjustable resistor 19, a data acquisition board 20, a capacitor 21, and an ammeter 22. The adjustable resistor 19 is connected to both the AC power supply 18 and the data acquisition board 20 via wires. The adjustable resistor 19 allows adjustment of the current in the AC circuit. The ammeter 22 is connected to the capacitor 21 and the carbon rod 44 via wires. The capacitor 21 is used to prevent interference from the electrochemical testing system to the AC power. The ammeter 22 is an AC ammeter used to read the current in the circuit. The capacitor 21 is connected to the AC power supply 18 via wires, and the carbon rod 44 is connected to the data acquisition board 20 via wires. The system has a 0-connection configuration. Through the settings of the data acquisition board 20, the AC waveform between the material sample 43 and the carbon rod 44 can be acquired. The material sample 43 is connected to the adjustable resistor 19 via a wire. The electrochemical testing system includes an electrochemical workstation 6, an inductor 23, and two counter electrodes 5 located in the electrolyte. The two counter electrodes 5 and the reference electrode 47 are all connected to the electrochemical workstation 6 via wires. The electrochemical workstation 6 is connected to one end of the inductor 23, and the other end of the inductor 23 is connected to the wire connecting the material sample 43. The inductor 23 is designed to prevent AC interference to the electrochemical testing system, thus ensuring the independence of the two circuits.

[0022] The steps for fabricating the matching test piece 4 are as follows: cut the metal material into a 10×10mm material sample 43. Except for exposing one 10×10mm surface as the working surface, the other surfaces are encapsulated in a PVC tube 41 with epoxy resin 42. The back of the working surface is connected to the wire. Drill a small hole 45 of about 1mm in the matching test piece 4. The small hole 45 is filled with saturated KCl agar. The bottom of the matching test piece 4 is connected to a U-shaped tube 46 filled with saturated KCl solution as a salt bridge. One end of the U-shaped tube 46 is connected to the small hole 45. The other end of the U-shaped tube 46 is provided with a reference electrode 47. The carbon rod 44 and the small hole 45 are symmetrically distributed on both sides of the material sample 43, and are also 1mm apart from the material sample 43.

[0023] Working principle: During use, the temperature and humidity control system controls the generation and maintenance of the liquid film. The thickness of the liquid film can be controlled to a minimum of 10µm by adding appropriate nonionic surfactants. The liquid film thickness is slowly adjusted by the micrometer screw gauge 9 and the thickness is measured multiple times until the liquid film thickness reaches the predetermined value. The AC waveform between the material sample 43 and the carbon rod 44 is collected by the data acquisition board 20. The corrosion degree of the test piece is measured by the electrochemical testing system.

[0024] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for electrochemical measurement of atmospheric corrosion of a metal material under alternating current interference, characterized by: The utility model relates to a temperature and humidity control system, which comprises a cavity (1), a plastic sleeve (2), a matching test piece (4), an electrochemical workstation (6), a constant-temperature circulating water bath (13), an ultrasonic atomizer (14) and a constant-temperature water bath (16), wherein the middle part of the inner cavity bottom of the cavity (1) is provided with the plastic sleeve (2), the middle part of the inner cavity bottom of the plastic sleeve (2) is provided with the matching test piece (4), the matching test piece (4) comprises a PVC pipe (41), an epoxy resin (42), a material sample (43), a carbon rod (44) and a reference electrode (47), the inner cavity of the plastic sleeve (2) is filled with an electrolyte, one side of the inner cavity top end of the cavity (1) is provided with a temperature and humidity meter (8), the middle part of the inner cavity top end of the cavity (1) is provided with a screw micrometer (9), one side of the cavity (1) is provided with the constant-temperature circulating water bath (13), the water outlet of the constant-temperature circulating water bath (13) is connected with one side of the inner cavity top end of the plastic sleeve (2) through a water outlet pipe (10), the inner cavity bottom end of the plastic sleeve (2) is connected with the constant-temperature circulating water bath (13) through a reflux pipe (12), the other side of the cavity (1) is provided with the ultrasonic atomizer (14) and the constant-temperature water bath (16), the inner cavity of the constant-temperature water bath (16) is provided with a moisture pipe (15), one end of the moisture pipe (15) is connected with the gas outlet of the ultrasonic atomizer (14), the other end of the moisture pipe (15) penetrates through the side wall of the cavity (1) bottom end and extends into the inner cavity of the cavity (1), and the top end of the other side of the inner cavity of the cavity (1) is provided with a moisture outlet (11), and the other end of the moisture pipe (15) is provided with a moisture flow control valve (17); An external alternating current loop comprises an alternating current power supply (18), an adjustable resistor (19), a data acquisition board card (20), a capacitor (21) and an ammeter (22), the adjustable resistor (19) is connected with the alternating current power supply (18) and the data acquisition board card (20) through wires, the ammeter (22) is connected with the capacitor (21) and the carbon rod (44) through wires, the capacitor (21) is connected with the alternating current power supply (18) through a wire, the carbon rod (44) is connected with the data acquisition board card (20) through a wire, and the material sample (43) is connected with the adjustable resistor (19) through a wire; An electrochemical test system comprises an electrochemical workstation (6), an inductor (23) and two counter electrodes (5) in the electrolyte, the two counter electrodes (5) and the reference electrode (47) are connected with the electrochemical workstation (6) through wires, the electrochemical workstation (6) is connected with one end of the inductor (23), and the other end of the inductor (23) is connected with the wire connected with the material sample (43). ​ The manufacturing steps of the matched test piece (4) are as follows: cutting a metal material into a material sample (43) with a cross section of 10*10 mm, except that one 10*10 mm surface is exposed as a working surface, the rest surfaces are encapsulated in a PVC tube (41) by epoxy resin (42), wherein the back surface of the working surface is connected with a wire, a 1 mm small hole (45) is drilled on the matched test piece (4), the small hole (45) is filled with saturated KCl agar, the bottom of the matched test piece (4) is connected with a U-shaped tube (46) filled with saturated KCl solution as a salt bridge, one end of the U-shaped tube (46) is connected with the small hole (45), the other end of the U-shaped tube (46) is provided with a reference electrode (47), and carbon rods (44) are symmetrically distributed on both sides of the material sample (43) and spaced apart from the material sample (43) by 1 mm.

2. The apparatus for electrochemical measurement of atmospheric corrosion of a metal material under AC interference according to claim 1, characterized by: The part of the moisture tube (15) in the thermostatic water bath (16) is in a spiral shape.

3. The apparatus for electrochemical measurement of atmospheric corrosion of a metal material under AC interference according to claim 1, characterized in that: The liquid level of the electrolyte is higher than the height of the matched test piece (4).

4. The apparatus for electrochemical measurement of atmospheric corrosion of a metal material under AC interference according to claim 1, characterized by: The material of the plastic sleeve (2) is heat-conducting plastic.

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