Electrochemical test apparatus for microbial corrosion under stress coupling

Abstract

This invention discloses an electrochemical testing device for microbial corrosion under stress coupling. The device includes a corrosion reaction tank and a bending loading fixture. The corrosion reaction tank is inverted U-shape, with an opening in the side wall. A gasket is installed at the opening, and the gasket has a central hole. The bending loading fixture is fixed at the opening. The bending loading fixture includes a loading support, a loading rod, and a horizontally movable loading module located inside the loading support. At least one pair of rollers are fixed to the inner side of the loading support legs. One or more grooves are provided on the end face of the loading module opposite to the opening, and rollers can be accommodated within the grooves. The testing device of this invention ensures data accuracy and has the advantages of convenient disassembly, simple design, and small size.

Description

Technical Field

[0001] This invention relates to an electrochemical testing device for microbial corrosion of metallic materials, specifically a device that can test the corrosion resistance of samples under the combined action of bending stress and microbial corrosion environment. Background Technology

[0002] Acidic oil and gas fields contain large amounts of corrosive media such as H2S and CO2, leading to severe corrosion problems in surface gathering and transportation pipeline systems. Furthermore, many oil and gas fields in China face serious microbiologically influenced corrosion (MIC) hazards in their gathering and transportation pipelines. Pipeline failures caused by corrosion perforation frequently result in leaks and even explosions. Among the various microbial communities present in oil and gas gathering and transportation systems, sulfate-reducing bacteria (SRB) are the most numerous and harmful. In US oil well production, corrosion caused by sulfate-reducing bacteria accounts for over 77%, and the corrosion rate of steel can increase by approximately 15 times under the synergistic effect of sulfate-reducing bacteria.

[0003] During service, pipelines are not only exposed to corrosive media and microorganisms, but stress also significantly impacts their safe operation. Local bending deformation, in particular, creates a vulnerable point, making pipelines susceptible to corrosion. Therefore, studying the combined effects of stress and microorganisms in corrosive media on metal corrosion behavior is crucial. However, current electrochemical corrosion testing equipment rarely measures the corrosion resistance of samples under the combined effects of stress and microorganisms in corrosive media. Furthermore, the stress conditions on pipelines vary in different circumferential directions, and the deposition and adhesion characteristics of microorganisms differ at different locations within the pipeline. Therefore, it is essential to study the corrosion characteristics under the combined effects of stress and microorganisms at different locations within the pipeline.

[0004] For example, CN107727564, "Electrochemical Testing Device for Microbial Corrosion of Metals in Flow Systems," describes a device that allows microorganisms to aggregate and grow on metal surfaces, enabling real-time electrochemical measurement of microbial corrosion of metal materials in flow systems. CN109507263, "Test System for Corrosion of Grounded Metal Materials by Microorganisms," discloses a test system for testing the corrosion of grounded metal materials by microorganisms. CN104458559, "Stress-Electrochemical Corrosion Testing Device," utilizes a weight to provide constant tensile force to study stress corrosion in the presence of anaerobic bacteria at different temperatures. CN102590298, "Method for Testing the Resistance of Antibacterial Stainless Steel to Microbial Corrosion Using Electrochemical Means," specifically introduces a method for testing the resistance of antibacterial stainless steel to microbial corrosion using electrochemical means. Furthermore, existing testing devices and methods have many limitations: they are inconvenient to disassemble and perform multiple measurements; the working area of ​​the sample is manually sealed, resulting in inaccurate working area and poor parallelism; the devices are complex in design, large in size, and not easily portable. Summary of the Invention

[0005] To overcome the shortcomings of existing microbial corrosion testing devices, such as the inability to simultaneously couple the bending stress under corrosive media, the inability to simulate coupled corrosion effects in different locations of pipelines, complex device design, inaccurate sample working area, and difficulty in disassembly, this invention provides an electrochemical testing device for microbial corrosion under corrosive media and bending stress. This device can test the microbial corrosion performance of samples under bending stress, simultaneously simulate corrosion conditions at the bottom and sides, and features a simple structure, a defined sample working area, and is easy to carry and disassemble.

[0006] The technical solution adopted in this invention is as follows:

[0007] An electrochemical testing device for microbial corrosion under stress coupling includes an electrochemical workstation, a bending loading fixture a, a corrosion reaction tank, and a constant temperature chamber; the corrosion reaction tank is in the shape of an inverted "U", and the bending loading fixture a is fixed to the side wall of the corrosion reaction tank (vertically arranged).

[0008] The side wall of the corrosion reaction tank is provided with an opening, and a sealing and insulating soft gasket is provided at the opening. The opening in the middle of the sealing and insulating soft gasket is matched or consistent with the opening area of ​​the corrosion reaction tank.

[0009] The bending loading fixture a includes a loading bracket a, a loading rod a, and a loading module a located inside the loading bracket a and movable left and right; wherein,

[0010] —The loading bracket a is hollow inside and has an opening on one side facing the reaction tank; there are inwardly protruding legs a on opposite sides of the opening, and at least one pair of symmetrically arranged rollers a are fixed on the inner end face of the legs a (i.e. the end face away from the opening of the reaction tank).

[0011] —The loading module a has at least one or more symmetrically arranged grooves a on its end face opposite to the opening, and the grooves a include rollers a that can be accommodated therein;

[0012] —The loading module a is connected to the loading rod a, and the loading module a can only move horizontally (without vertical displacement) as the loading rod a moves.

[0013] Furthermore, when the loading rod a rotates, it can drive the loading module a to move to the left or right.

[0014] Furthermore, the loading bracket a is fixed to the side wall of the reaction tank (the end face perpendicular to the surface of the "U"-shaped opening) by at least a pair of fastening bolts a and fastening nuts a.

[0015] Furthermore, the loading rod a and the loading module a are connected by a thread, with the loading rod a passing through the loading bracket a (right end face). In this case, the loading rod a can only rotate without any relative (left-right) displacement relative to the loading bracket a. Alternatively, one end of the loading rod a is threaded to the loading bracket a, and the other end (left end) of the loading rod a is fixedly connected to the loading module a. The loading rod a can rotate within the loading module a, but without any left-right displacement relative to the loading module a. The threaded connection is a conventional structure in this field.

[0016] Furthermore, the loading module a can adopt an internal hollow structure.

[0017] Furthermore, the matching of the openings in the sealing and insulating pad with the openings in the side planar area means that the opening areas of the two are basically equivalent or not much different.

[0018] Furthermore, the length of the rollers a on the support leg of the loading bracket a should be greater than or equal to the width of the test sample, and the spacing between the rollers on the support leg should be less than the length of the test sample. The support leg on one side of the loading bracket a can be a continuous structure or a hollow structure in the middle.

[0019] Furthermore, the loading module a has one or more rollers a (grooves a), preferably two or more. For two or more rollers a (grooves a), the distance between the outermost pair of rollers a (grooves a) should be less than the distance between the grooves a (rollers a) on the loading bracket legs. Through the rollers on the loading bracket legs and the grooves and rollers on the loading module, the loading fixture can achieve different forms of bending deformation and stress loading on the sample, such as four-point bending, three-point bending, and U-shaped bending.

[0020] Furthermore, the rollers on the legs of loading module a and loading bracket a are used to place the test sample. After the test sample is placed, one or a pair of rollers are inserted into the appropriate grooves on the loading module as needed.

[0021] Furthermore, the roller a can be made of a material with a certain rigidity and that is not easily deformed, such as glass or ceramic. Roller a is preferably cylindrical.

[0022] Furthermore, the corrosion reaction tank is shaped like an inverted "U", and a bending loading fixture b is fixedly installed on the upper surface (end face) of the inverted "U" shaped opening; at the same time, an opening is provided on the upper surface of the inverted "U" shaped opening, and the opening is at the same horizontal height as the opening on the side wall of the reaction tank; a sealing and insulating soft gasket is installed at the opening, and the shape and size of the central opening of the sealing and insulating soft gasket match the opening area of ​​the corrosion reaction tank;

[0023] The bending loading fixture b includes a loading bracket b, a loading rod b, and a loading module b located inside the loading bracket b and movable vertically; wherein,

[0024] —The loading bracket b is hollow inside and open at the top; there are inwardly protruding legs b on opposite sides of the upper opening, and at least a pair of symmetrically arranged rollers b are fixed on the inner end face of the legs b (i.e. the end face away from the opening of the reaction tank).

[0025] —The loading module b has at least one or more symmetrically arranged grooves b on its end face opposite to the opening, and the grooves b include rollers b that can be accommodated therein;

[0026] —The loading module b is connected to the loading rod b, and the loading module b can only move up and down (without horizontal displacement) as the loading rod b moves.

[0027] Furthermore, the rotation of the loading rod b can drive the loading module to move up or down.

[0028] Furthermore, the loading bracket b is fixed to the plane of the inverted U-shaped opening of the reaction tank by at least a pair of fastening bolts b and fastening nuts b.

[0029] Furthermore, the loading rod b and the loading module b are connected by a thread, with the loading rod b passing through the lower end face of the loading bracket b. In this case, the loading rod b can only rotate without any relative (vertical) displacement relative to the loading bracket b. Alternatively, the lower end (lower part) of the loading rod b is threaded to the loading bracket b, and the upper end of the loading rod b is fixedly connected to the loading module b. The loading rod b can rotate within the loading module b, but without any vertical displacement relative to the loading module. The threaded connection is a conventional structure in this field.

[0030] Furthermore, the loading module b can adopt an internal hollow structure.

[0031] Furthermore, the matching of the openings in the sealing and insulating pad with the openings in the recessed flat area means that the opening areas of the two are not significantly different.

[0032] Furthermore, the length of the rollers b on the support leg b of the loading bracket should be greater than or equal to the width of the test sample, and the spacing between the rollers on the support leg should be less than the length of the test sample. One leg of the loading bracket can be a continuous structure or a hollow structure in the middle.

[0033] Furthermore, the loading module b is provided with one or more rollers b (grooves b), preferably two or more. For two or more rollers b (grooves b), the distance between the outermost pair of rollers b (grooves b) should be less than the distance between the grooves b (rollers b) on the loading bracket legs. Through the rollers provided on the loading bracket legs, as well as the grooves and rollers on the loading module, the loading fixture b can achieve different forms of bending deformation and stress loading on the sample, such as four-point bending, three-point bending, and U-shaped bending.

[0034] Furthermore, the rollers on the support legs of loading module b and loading bracket b are used to place the test sample. After the test sample is placed, one or a pair of rollers are inserted into the appropriate grooves on the loading module as needed.

[0035] Furthermore, the roller b can be made of a material with a certain rigidity and that is not easily deformed, such as glass or ceramic. The roller is preferably cylindrical.

[0036] Furthermore, the upper surface of the corrosion reaction tank has at least four openings, preferably spaced apart. Two of these openings are respectively fitted with a salt bridge and a platinum sheet, with a reference electrode connected inside the salt bridge. The salt bridge and platinum sheet should be immersed in the reaction solution of the reaction tank. The salt bridge, platinum sheet, and upper surface of the reaction tank are sealed and fixed. The other set of openings can be an air inlet and an air outlet, a chemical dosing port, and a sampling port. The air inlet (chemical dosing port) is used to introduce gases such as nitrogen, hydrogen sulfide, and carbon dioxide into the corrosion reaction tank or to add chemical solutions. The air outlet (sampling port) is used to discharge gases or take samples.

[0037] Furthermore, the salt bridge and platinum sheet should be positioned near the opening between the loaded sample and the reaction cell. The lower end of the salt bridge and platinum sheet should be at the same horizontal height as the opening on the plane of the inverted "U"-shaped opening of the reaction cell and the opening on its side surface.

[0038] Furthermore, the sealing and insulating pad can be made of elastic and waterproof materials such as silicone rubber and polyolefins.

[0039] Furthermore, the openings of the corrosion reaction tank and the sealing insulating pad are square or round, which makes it easy to determine the contact area between the sample and the reaction solution.

[0040] Furthermore, the electrochemical workstation includes an auxiliary electrode interface, a working electrode interface, and a reference electrode interface. The platinum sheet is connected to the auxiliary electrode interface of the workstation, the sample loaded in the fixture is connected to the working electrode interface of the workstation, and the reference electrode is connected to the reference electrode interface of the workstation.

[0041] Furthermore, the constant temperature chamber is used to house the corrosion reaction pool and ensure a constant temperature in the testing environment to study the corrosive effects of microorganisms on the sample at different temperatures. Small holes are provided on the side wall of the constant temperature chamber for connecting the necessary pipelines from the corrosion reaction pool to external equipment. A salt bridge connects to the reference electrode, and the platinum sheet, the sample in the loading fixture, and the reference electrode are respectively connected to the respective electrode interfaces of the electrochemical workstation.

[0042] Furthermore, the corrosion reaction tank can contain various solution media such as potassium chloride and hydrochloric acid according to the test requirements.

[0043] In this invention, the sample is bent and deformed within the fixture, and the fixture is fixed to the plane and side of the inverted "U"-shaped opening at the bottom of the corrosion reaction pool (the end face perpendicular to the surface of the "U"-shaped opening) by the fixture, so that the sample in the fixture is in close contact with the soft pad of the corrosion reaction pool and the loading stress on the sample is kept constant.

[0044] The corrosion reaction tank can be filled with culture medium inoculated with specific bacteria, according to the test requirements.

[0045] The air inlet can be used to introduce gases such as nitrogen, hydrogen sulfide, and carbon dioxide.

[0046] The dosing hole can be filled with a bactericide for specific bacteria.

[0047] The present invention also provides an electrochemical test method for microbial corrosion under stress coupling, wherein the test apparatus described above is used.

[0048] Compared with the prior art, the testing apparatus of the present invention has the following beneficial effects:

[0049] 1. This invention allows for the separate study and comparison of the effects of different magnitudes of stress applied in the horizontal and vertical directions on microbial corrosion. Furthermore, by placing fixed clamps on the surface (end face) and side face (the end face perpendicular to the surface of the inverted "U"-shaped opening of the corrosion reaction tank to load the sample, the differences in the effects of microorganisms on different planes at the same horizontal height under stress can be simulated. Simultaneously, by changing the fixed position of the side clamps, the characteristics and differences of microbial corrosion under stress coupling in different circumferential directions can be studied.

[0050] 2. This invention introduces a bolt structure into the corrosion reaction tank and the loading fixture, allowing the loading fixture to be fixed to the corresponding position in the corrosion reaction tank via fastening bolts. This facilitates loading of the loading fixture onto the reaction tank and ensures the tank is securely positioned. It also guarantees that the force applied to the sample after contact with the gasket remains constant and stable, enabling more accurate determination of the applied load value. The loading method can be manual mechanical loading or electromechanical loading using a motor and stress sensor.

[0051] 3. By using the grooves on the lower support legs of the loading bracket, the rollers installed in the grooves, the grooves on the lower end face of the loading module, and the insertable rollers, and by using the rollers made of insulating material, it can be ensured that the loading module can apply bending stress to the sample without directly contacting the sample, thereby ensuring the accuracy of the test data.

[0052] 4. To address the shortcomings of existing technologies, this invention provides an electrochemical evaluation device for microbial corrosion under bending stress, thus overcoming these deficiencies. Furthermore, the testing device of this invention eliminates the need for waterproof sealing during sample assembly, and the working area of ​​the sample does not require manual sealing each time. The working area is also precise and exhibits high parallelism. In addition, the device of this invention is easy to disassemble, portable, simple in design, and compact in size. Attached Figure Description

[0053] Figure 1 This is a front sectional view of the electrochemical test device for microbial corrosion under stress coupling according to the present invention.

[0054] Figure 2 This is a left view of the corrosion reaction tank in the device of the present invention.

[0055] Figure 3 This is a top view of the corrosion reaction tank in the device of the present invention.

[0056] Figure 4 This is a structural diagram of the bending loading fixture a.

[0057] Figure 5This is a structural diagram of the bending loading fixture b.

[0058] Figure 1-5 In the text, each number corresponds to:

[0059] 100-Electrochemical workstation a, 200-Constant temperature chamber, 300-First loading fixture, 400-Corrosion reaction tank, 500-Second loading fixture, 600-Electrochemical workstation b;

[0060] 30-Gasket a, 31-Fasting bolt a, 32-Fasting nut a, 33-Support a, 34-Groove a, 35-Loading screw a, 36-Loading bracket a, 37-Loading module a, 38-Roller a, 39-Sample a;

[0061] 50-Gasket b, 51-Fasting bolt b, 52-Fasting nut b, 53-Support b, 54-Groove b, 55-Loading screw b, 56-Loading bracket b, 57-Loading module b, 58-Roller b, 59-Sample b;

[0062] 41-Salt bridge, 42-Reference electrode, 43-Platinum sheet, 44-Side opening of corrosion reaction tank, 45-Bottom opening of corrosion reaction tank, 46-Air inlet / dosing hole, 47-Air outlet, 48-Reference electrode interface, 49-Auxiliary electrode interface. Detailed Implementation

[0063] To make the objectives, technical solutions, and features of this invention clearer, the invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be noted that the described embodiments are only some embodiments of this invention. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0064] like Figure 1 , 2 As shown in Figure 3, the stress-coupled microbial corrosion electrochemical testing device of the present invention includes an electrochemical workstation a100, a constant temperature chamber 200, a corrosion reaction tank 400, and a bending loading fixture a300. The corrosion reaction tank 400 is in the shape of an inverted "U", with an opening 44 on its right side wall. The bending loading fixture a300 covers the opening 44 and is fixedly installed on the right side wall. A sealing insulating gasket 30 is installed in the opening 44, and the shape and size of the central opening of the sealing insulating gasket 30 match the opening 44 of the corrosion reaction tank. A fastening nut a32 passes through the corresponding opening on the side of the corrosion reaction tank 400, and the loading bracket a36 of the bending loading fixture a is fixed to the side wall of the reaction tank by a fastening bolt a31.

[0065] The bending loading fixture a300 includes a loading bracket a36, a loading screw a35, and a loading module a37 located inside the loading bracket and movable left and right. The loading bracket a36 is hollow inside and open on the left side; opposite sides of the left opening have inwardly protruding legs a33, and at least a pair of symmetrically arranged rollers a38 are fixed to the inner end face of the legs a33 (i.e., the end face away from the opening of the reaction cell). The end face of the loading module opposite to the opening has at least one or more symmetrically arranged grooves a34, and the grooves include rollers a38 that can be accommodated therein. The loading module a37 and the loading screw a35 can be connected by threads, and the loading module a37 can only move left and right (without vertical displacement) with the movement of the loading screw a35. Preferably, when the loading screw a35 rotates, it can drive the loading module a37 to move left or right. The sample a39 is fixed in the loading bracket a36 by the cylindrical rollers a38 placed in the grooves. An open gasket a30 is provided between the sample a39 and the corrosion reaction tank 400. The open gasket a30 has an opening in the middle, and the middle force-bearing part of the sample a39 contacts the corrosive solution in the corrosion reaction tank 400 through the opening. By rotating the loading screw a35, the loading module a37 of the fixture moves towards the opening of the corrosion reaction tank 400, thereby loading the sample a39.

[0066] In a preferred embodiment of the present invention, the electrochemical testing device further includes a bending loading clamp b500. An opening 45 is provided on the upper surface of the concave notch of the corrosion reaction cell, and a sealing insulating pad b50 is correspondingly provided on the opening 45. The bending loading clamp b500 is installed covering the opening 45. The sealing insulating pad has a central opening, and its shape and size match the opening of the corrosion reaction cell. A fastening nut b52 is passed through the bottom of the corrosion reaction cell 400, and the loading bracket b56 of the bending loading clamp b500 is fixed to the central bottom of the corrosion reaction cell 400 by fastening bolts b51 and fastening nut b52.

[0067] The bending loading fixture b 500 includes a loading bracket b 56, a loading screw b 55, and a loading module b 57 located inside the loading bracket and movable vertically. The loading bracket b 56 is hollow inside and open at the top; opposite sides of the upper opening have inwardly protruding legs b 53, and at least a pair of symmetrically arranged rollers b 58 are fixed to the inner end face of the legs b 53 (i.e., the end face away from the opening of the reaction tank). The end face of the loading module opposite the opening has at least one or more symmetrically arranged grooves b 54, each groove containing a roller b 58. The loading module b 57 and the loading screw b 55 can be threaded together, and the loading module b 57 can only move vertically (without horizontal displacement) with the movement of the loading screw b 55. Preferably, when the loading screw b 55 rotates, it can drive the loading module b 57 to move upward or downward. The sample b59 is fixed in the loading bracket b56 by a cylindrical roller b58 placed in a groove. An open gasket b50 is provided between the sample b59 and the corrosion reaction tank 400. The open gasket b50 has an opening in the middle, and the middle force-bearing part of the sample b59 contacts the corrosive solution in the corrosion reaction tank 400 through the opening. By rotating the loading screw b55, the loading module b57 of the fixture moves towards the opening of the corrosion reaction tank 400, thereby loading the sample b59.

[0068] The corrosion reaction tank 400 has multiple holes on its upper part: 46 - inlet / dosing port, 47 - outlet, 48 - reference electrode interface, and 49 - auxiliary electrode interface. The inlet / dosing port 46 can be used to introduce corrosive gases such as hydrogen sulfide and carbon dioxide, and to add specific bactericides; the outlet 47 is used to discharge gases introduced into the solution; the reference electrode port 48 houses the salt bridge 41 and the reference electrode 42; the auxiliary electrode port 49 houses the platinum sheet 43. The salt bridge 41 and the platinum sheet 43 are placed close to the loaded sample a 39 and the loaded sample b 59. The reference electrode 42, the platinum sheet 43, and the loaded sample a are connected to the reference electrode interface, auxiliary electrode interface, and working electrode interface of the electrochemical workstation 1, respectively. The reference electrode 42, the platinum sheet 43, and the loaded sample b are connected to the reference electrode interface, auxiliary electrode interface, and working electrode interface of the electrochemical workstation 600, respectively.

[0069] Identical loading specimens a and b are selected, meaning that the material and dimensions of both specimens are identical. The installation conditions of the specimens on the two fixtures are also identical, including the material and shape of rollers a38 and b58, and the material, opening shape, and size of the open gaskets a30 and b50. The same displacement is applied to loading screws a35 and b55, meaning the magnitude of the force on specimens a39 and b59 is identical. Under these conditions, the differences in corrosion behavior of specific metal specimens under specific stress conditions and with varying planar orientations due to microbial stress coupling can be simulated and studied.

[0070] In this invention, the reaction solution also includes microorganisms. The selected microorganisms can be sulfate-reducing bacteria (SRB), and the bacterial strains are cultured using the liquid culture medium and experimental conditions recommended by the API. Since the optimal pH for SRB growth is 7.0-7.5, the pH of the culture medium is adjusted to 7.2 using sodium hydroxide solution. Before use, the SRB culture medium is deoxygenated with nitrogen for 1 hour, and then sealed and sterilized in a high-temperature autoclave at 121°C + 15 psi for 20 minutes. The bacteria are inoculated into the culture medium in an anaerobic glove box and placed in a 38°C biochemical incubator for enrichment culture. The culture medium is added to the corrosion reaction tank 400, which is placed in a 38°C constant temperature incubator 200 during the experiment. Open circuit potential, polarization curves, and electrochemical impedance spectroscopy (EIS) data can be measured as needed for the experiment. Following the tests, samples a39 and b59 underwent timely treatment, including fixing corrosion products for macroscopic photographic observation, gold sputtering for scanning electron microscopy observation, surface bacterial concentration measurement, and pitting corrosion and depth measurement for samples a39 and b59. Based on the test results, the corrosion characteristics and differences of the samples under microbial stress coupling at different orientations can be compared.

Claims

1. An electrochemical testing device for microbial corrosion under stress coupling, the device comprising an electrochemical workstation, a bending loading fixture a, a corrosion reaction tank, and a constant temperature chamber; The corrosion reaction tank is in the shape of an inverted "U", and the bending loading fixture a is fixed to the side wall of the corrosion reaction tank; The side wall of the corrosion reaction tank is provided with an opening, and a sealing and insulating soft gasket is provided at the opening. The opening in the middle of the sealing and insulating soft gasket is matched or consistent with the opening area of ​​the corrosion reaction tank. The bending loading fixture a includes a loading bracket a, a loading rod a, and a loading module a located inside the loading bracket a and movable left and right; wherein, —The loading bracket a is hollow inside and has an opening on one side facing the reaction tank; there are inwardly protruding legs a on opposite sides of the opening, and at least one pair of symmetrically arranged rollers a are fixed on the inner end face of the legs a. —The loading module a has at least one or more symmetrically arranged grooves a on its end face opposite to the opening, and the grooves a include rollers a that can be accommodated therein; —The loading module a is connected to the loading rod a, and the loading module a can only move horizontally as the loading rod a moves; A bending loading fixture b is fixedly installed on the upper surface of the inverted "U"-shaped opening of the corrosion reaction tank; at the same time, an opening is provided on the upper surface of the inverted "U"-shaped opening, which is at the same horizontal height as the opening on the side wall of the reaction tank; a sealing and insulating soft gasket is installed at the opening, and the shape and size of the central opening of the sealing and insulating soft gasket match the opening area of ​​the corrosion reaction tank.

2. The experimental apparatus according to claim 1, characterized in that, The loading bracket a is fixed to the side wall of the reaction tank by at least one pair of fastening bolts a and fastening nuts a.

3. The experimental apparatus according to claim 1, characterized in that, The loading rod a is connected to the loading module a by a thread, and the loading rod a passes through the loading bracket a; or, one end of the loading rod a is connected to the loading bracket a by a thread, and the other end of the loading rod a is fixedly connected to the loading module a. The loading rod a can rotate within the loading module a, but does not produce left or right displacement relative to the loading module a.

4. The experimental apparatus according to claim 1, characterized in that, The loading module a adopts an internal hollow structure.

5. The experimental apparatus according to claim 1, characterized in that, The length of the roller a set on the support leg of the loading bracket a is greater than or equal to the width of the test sample, and the spacing between the rollers on the support leg is less than the length of the test sample.

6. The experimental apparatus according to claim 1, characterized in that, The number of scroll bars a on the loading module a is set to more than one.

7. The experimental apparatus according to claim 6, characterized in that, The number of scroll bars a on the loading module a is set to two or more.

8. The test apparatus according to claim 7, characterized in that, For two or more rollers a, the distance between the outermost pair of rollers a is less than the distance between the grooves a on the loading bracket feet.

9. The experimental apparatus according to claim 1, characterized in that, The bending loading fixture b includes a loading bracket b, a loading rod b, and a loading module b located inside the loading bracket b and movable vertically; wherein, The loading bracket b is hollow inside and open at the top; there are inwardly protruding legs b on opposite sides of the upper opening, and at least one pair of symmetrically arranged rollers b are fixed to the inner end face of the legs b. The end face of the loading module b opposite to the opening has at least one or more symmetrically arranged grooves b, and the grooves b include rollers b that can be accommodated therein. The loading module b is connected to the loading rod b, and the loading module b can only move up and down as the loading rod b moves.

10. The experimental apparatus according to claim 1, characterized in that, The loading bracket b is fixed to the plane of the inverted U-shaped opening of the reaction tank by at least one pair of fastening bolts b and fastening nuts b.

11. The test apparatus according to claim 1, characterized in that, The loading rod b and the loading module b are connected by a thread, and the loading rod b passes through the loading bracket b; or, the lower part of the loading rod b is connected to the loading bracket b by a thread, and the upper end of the loading rod b is fixedly connected to the loading module b. The loading rod b can rotate within the loading module b, but does not produce vertical displacement relative to the loading module.

12. The experimental apparatus according to claim 1, characterized in that, The length of the rollers b set on the support foot of the loading bracket b is greater than or equal to the width of the test sample, and the spacing between the rollers on the support foot is less than the length of the test sample.

13. The experimental apparatus according to claim 1, characterized in that, The number of scroll bars b is set to one or more on the loading module b.

14. The test apparatus according to claim 13, characterized in that, The number of scroll bars b on the loading module b is set to two or more.

15. The test apparatus according to claim 14, characterized in that, The distance between the outermost pair of rollers b on the loading module b is less than the distance between the rollers b on the loading bracket feet.

16. The experimental apparatus according to claim 1, characterized in that, The upper surface of the corrosion reaction tank is provided with at least four openings, and the four or more openings are spaced apart on the upper surface.

17. The experimental apparatus according to claim 16, characterized in that, Two of the openings are respectively equipped with a salt bridge and a platinum sheet, with a reference electrode connected inside the salt bridge; the other set of openings are the air inlet / outlet and the drug dosing / sampling port, respectively.

18. The test apparatus according to claim 17, characterized in that, The salt bridge and platinum sheet are positioned near the opening between the loaded sample and the reaction cell; the lower ends of the salt bridge and platinum sheet are at the same horizontal height as the openings on the inverted "U"-shaped opening plane and the side surface of the reaction cell.

19. The experimental apparatus according to claim 1, characterized in that, The openings of the corrosion reaction tank and the sealing insulating pad are square or round.

20. The experimental apparatus according to claim 18, characterized in that, The electrochemical workstation includes an auxiliary electrode interface, a working electrode interface, and a reference electrode interface; the platinum sheet is connected to the auxiliary electrode interface of the workstation, the sample loaded in the fixture is connected to the working electrode interface of the workstation, and the reference electrode is connected to the reference electrode interface of the workstation.

21. The experimental apparatus according to claim 1, characterized in that, The constant temperature chamber is used to contain the corrosion reaction tank and ensure that the temperature of the test environment is constant.

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