An electrochemical noise testing system and testing method

Abstract

This specification discloses an electrochemical noise testing system and method. By providing a system including a first digital multimeter, a second digital multimeter, a weak current amplifier, a reference electrode, a working electrode, and a counter electrode, the working electrode and the counter electrode are connected to the two current input measurement terminals of the weak current amplifier; the two voltage output terminals of the weak current amplifier are connected to the two voltage input measurement terminals of the first digital multimeter; the working electrode and the reference electrode are connected to the two voltage input measurement terminals of the second digital multimeter, for synchronous potential noise measurement with the current noise measurement, thereby achieving a combination of corrosion detection and monitoring, performing full-process, multi-scale electrochemical measurement of localized corrosion processes, and achieving accurate spatial positioning of corrosion sites.

Description

Technical Field

[0001] This specification relates to the field of electrochemical technology, and in particular to an electrochemical noise testing system and testing method. Background Technology

[0002] In modern equipment environments, corrosion testing systems are transitioning towards integrated support. Conventional electrochemical noise testing methods can obtain current and potential information of the natural corrosion process of the system, accurately reflecting the changes in corrosion status over time, and are better suited for real-time corrosion detection. However, conventional electrochemical noise measurements can only obtain statistical average information of the electrodes and cannot acquire spatial information of the location of localized corrosion on the electrode surface, thus having certain limitations in corrosion measurement.

[0003] Therefore, a more accurate spatial positioning electrochemical noise testing scheme is needed. Summary of the Invention

[0004] This specification provides an electrochemical noise testing system and method to address the following technical problem: the need for a more accurate spatial positioning electrochemical noise testing scheme.

[0005] To solve the above-mentioned technical problems, one or more embodiments of this specification are implemented as follows:

[0006] In a first aspect, embodiments of this specification provide an electrochemical noise testing system, the system comprising a first digital multimeter, a second digital multimeter, a weak current amplifier, a reference electrode, a working electrode, and a counter electrode, wherein: the working electrode and the counter electrode are connected to two current input measurement terminals of the weak current amplifier; the two voltage output terminals of the weak current amplifier are connected to two voltage input measurement terminals of the first digital multimeter; and the working electrode and the reference electrode are connected to two voltage input measurement terminals of the second digital multimeter for performing potential noise measurement synchronously with the current noise measurement.

[0007] In a second aspect, embodiments of this specification provide a testing method for an electrochemical noise testing system, comprising: measuring current noise based on the output voltage of a first digital multimeter to generate a current noise curve; measuring potential noise synchronously with the current noise measurement based on the output voltage of a second digital multimeter to generate a potential noise curve; and generating real electrochemical noise data based on the current noise curve and the potential noise curve, wherein the real electrochemical noise data characterizes the local corrosion current density of multiple working electrodes to be measured; wherein the system is as described in the first aspect.

[0008] The above-described at least one technical solution adopted in one or more embodiments of this specification can achieve the following beneficial effects: by providing a system including a first digital multimeter, a second digital multimeter, a weak current amplifier, a reference electrode, a working electrode, and a counter electrode, in which: the working electrode and the counter electrode are connected to the two current input measurement terminals of the weak current amplifier; the two voltage output terminals of the weak current amplifier are connected to the two voltage input measurement terminals of the first digital multimeter; the working electrode and the reference electrode are connected to the two voltage input measurement terminals of the second digital multimeter for synchronous potential noise measurement with the current noise measurement, thereby realizing the combination of corrosion detection and monitoring, performing full-process, multi-scale electrochemical measurement of local corrosion processes, and achieving accurate spatial positioning of corrosion sites. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of an electrochemical noise testing system provided in the embodiments of this specification.

[0011] Figure 2 A schematic diagram illustrating an exemplary test result provided in an embodiment of this specification;

[0012] Figure 3 This is a schematic diagram of a test process provided in an embodiment of this specification;

[0013] Figure 4 A schematic diagram of the connection of an array electrode in a system provided in an embodiment of this specification during testing;

[0014] Figure 5 Another schematic diagram of the array electrodes in a system provided in this specification during testing;

[0015] Figure 6 This is a schematic diagram illustrating the results of a test provided in an embodiment of this specification.

[0016] Figure reference numerals: 1-Weak current amplifier, 2-First digital multimeter, 3-Second digital multimeter, 4-Working electrode, 5-Counter electrode, 6-Reference electrode, 7-Array electrode, 8-High-speed matrix switch. Detailed Implementation

[0017] This specification provides an electrochemical noise testing system and testing method through its embodiments.

[0018] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0019] like Figure 1 As shown in Figure 1, an electrochemical noise testing system provided in an embodiment of this specification is included. The system comprises a first digital multimeter, a second digital multimeter, a weak current amplifier, a reference electrode, a working electrode, and a counter electrode. In the system:

[0020] The working electrode and the counter electrode are connected to the two current input measurement terminals of the weak current amplifier;

[0021] The two voltage output terminals of the weak current amplifier are connected to the two voltage input measurement terminals of the first digital multimeter.

[0022] The working electrode and the reference electrode are connected to the two voltage input measurement terminals of the second digital multimeter for synchronous potential noise measurement with the current noise measurement.

[0023] In the simplest architecture, such as Figure 1 As shown, the aforementioned noise measurement can be achieved using only one working electrode and one counter electrode.

[0024] Optionally, the working electrodes are in an array configuration; correspondingly, the array-configured working electrodes and the counter electrode are connected to the two current input measurement terminals of the weak current amplifier via a high-speed matrix switch; the array-configured working electrodes and the reference electrode are connected to the two voltage input measurement terminals of a second digital multimeter via a high-speed matrix switch. This allows for more accurate noise testing through coupling and comparison between multiple electrodes.

[0025] In this architecture, any one of the electrodes in the array can serve as the working electrode, and the remaining electrodes can serve as the counter electrode of that working electrode after coupling; in addition, the galvanic current of any working electrode in the array can be tested, and the working electrode with the largest galvanic current can be determined as the target electrode.

[0026] Based on the aforementioned electrochemical noise testing system, the following testing methods can be performed, specifically including:

[0027] The first digital multimeter of the electrochemical noise testing system is used to perform galvanic current testing to generate galvanic current test data. The galvanic current test data characterizes the local corrosion current density of multiple working electrodes under test. Therefore, the electrode with the largest current density among the local corrosion current densities can be identified as the target electrode for electrochemical noise measurement.

[0028] The current noise is measured based on the output voltage of the first digital multimeter, and a current noise curve is generated.

[0029] Based on the output voltage of the second digital multimeter, a potential noise measurement is performed synchronously with the current noise measurement to generate a potential noise curve;

[0030] Based on the current noise curve and the potential noise curve, real electrochemical noise data is generated. The real electrochemical noise data characterizes the local corrosion behavior information of the target electrode, thereby achieving accurate spatial positioning.

[0031] Taking the electrochemical noise test of X80 pipeline steel as an example, it can be performed as follows: Initialize the two NI PXIe-4081 and NIPXI-4022 chips, including setting parameters such as the test accuracy of current noise and potential noise, noise frequency, number of noise acquisition points, number of tests, and test interval; acquire electrochemical noise based on the output of the aforementioned system; after completing the aforementioned number of tests, the test system stops acquiring electrochemical noise and plots the current noise curve and the synchronous potential noise curve; then, remove the DC drift of the original noise data, and automatically save the original electrochemical noise measurement data and the local corrosion current density after removing the DC drift according to the test time. Figure 2 As shown, Figure 2 This is a schematic diagram illustrating an exemplary test result provided in an embodiment of this specification.

[0032] Furthermore, after obtaining the target working electrode, the electrode with the highest local corrosion current density can be identified as the target electrode, and the other working electrodes can be used as counter electrodes for electrochemical noise measurement.

[0033] For example, an electrode array can be used to perform continuous electrochemical noise measurements on the aforementioned target working electrode. The specific procedure is as follows: Figure 3 As shown, Figure 3This is a schematic diagram of a joint test procedure provided in the embodiments of this specification. First, all array electrodes are coupled using a high-speed matrix switch. Then, the array electrodes are scanned for galvanic potential and galvanic current using the high-speed matrix switch to obtain the galvanic corrosion state and localized corrosion current density of the electrode under test. The working electrode with the highest localized corrosion current density in this electrode array test is selected as the target electrode. Other electrodes are coupled using the high-speed matrix switch as counter electrodes. Through high-speed switching of the matrix switch, electrochemical noise measurement is continuously performed before the next electrode array test.

[0034] For example, when using NIPXI-2535 for noise testing, the specific test procedure is as follows: 1) Connect the column channels C0 to C(n-1) of NIPXI-2535 sequentially to each electrode in the electrode array (including the working electrode and the reference electrode); 2) Initialize the NIPXI-2535, the two NIPXIe-4081s, and the NIPXI-4022 according to the user's test requirements, including setting the electrode array test parameters and the electrochemical noise test parameters; 3) Connect the column channels C0 to C(n-1) of NIPXI-2535 one by one to the first row channel R0 for measuring the galvanic current, so as to achieve coupling of all electrodes.

[0035] After coupling for the user-specified time, perform the following steps one by one on column channels C0 to C(n-1):

[0036] S101, the column channel Ci (i = 0 to n-1) is disconnected from the first row channel R0 and connected to another second row channel R1 for thermocouple current measurement via NIPXI-2535;

[0037] S102 measures the current flowing between the first row channel R0 and the second row channel R1 using NIPXIe-4081 and NIPXI-4022, which is the galvanic corrosion current of the electrode connected to the channel.

[0038] S103, the column channel Ci is disconnected from the second row channel R1 and connected to another third row channel R2 for thermocouple potential measurement via NIPXI-2535;

[0039] S104, the potential difference between the third row channel R2 and the fourth row channel R3 connected to the reference electrode is measured by another NIPXIe-4081, which is the galvanic corrosion potential of the electrode connected to the channel.

[0040] S105, by using NIPXI-2535, disconnect column channel Ci from the third row channel R2 and connect it to the first row channel R0, so that all electrodes are recoupled together;

[0041] Following steps S101 to S105 above, after measuring the galvanic corrosion current and galvanic corrosion potential of all electrodes in the electrode array, plot the planar distribution of the galvanic current and galvanic potential of the electrode array and the statistical data of the average values ​​per column, and automatically save the measurement data according to the test time; then analyze the saved galvanic corrosion current data, determine the electrode number with the largest current, and use this electrode as the target working electrode for electrochemical noise testing, and perform the following four steps one by one on each of the column channels C0 to C(n-1) of the NIPXI-2535:

[0042] S1, via NIPXI-2535, disconnects the column channel Ci connected to the target working electrode with the largest thermocouple current from the first row channel R0 and connects it to another second row channel R1 used for current noise measurement, as follows: Figure 4 As shown; S2, the current flowing between the first row channel R0 and the second row channel R1 is measured by NIPXIe-4081 and NIPXI-4022, which is the single current noise of the target electrode with the largest current under study.

[0043] S3, via NIPXI-2535, disconnect column channel Ci from the second row channel R1 and connect it to another third row channel R2 for potential measurement, as follows. Figure 5 As shown;

[0044] S4. The potential difference between the third row channel R2 and the fourth row channel R3 connected to the reference electrode is measured using another NIPXIe-4081. This difference represents the single-shot potential noise of the target electrode with the largest current under study.

[0045] exist Figure 4 and Figure 5 In the system shown, the target electrode has been selected as the working electrode with the largest galvanic current, and the other electrodes are coupled to become the counter electrodes.

[0046] Repeat steps S1 to S4 of the aforementioned process, making its single execution time M (e.g., 0.5) seconds, thereby achieving electrochemical noise acquisition at 1 / M (e.g., 2Hz). After completing the set number of tests, the test system stops electrochemical noise acquisition, plots current noise and potential noise curves, removes DC drift from the original noise data, and automatically saves the original electrochemical noise measurement data and the true electrochemical noise data after removing DC drift according to the test time. The NI PXI-2535 disconnects all row and column channels, releases all hardware resources in the modular hardware test system, closes all open data files, exits the visualization software test system, and ends the test.

[0047] During testing, the electrode array test can be repeated, and the current noise measurement and potential noise measurement can be repeated periodically to update the actual electrochemical noise data and the target electrode periodically. Generally, the operations of steps S101 to S105 are repeated every 2 hours, 1 day, or 5 days to measure the galvanic current and galvanic potential. Within the interval of the electrode array test, the operations of steps S1 to S4 can be repeated continuously for electrochemical noise testing. The interval between electrode array tests and electrochemical noise tests can be set via software according to user needs, and the number of sampling points for electrochemical noise can also be set via software (generally 1024 sampling points). Through electrode array testing, the entire process of localized corrosion can be measured, and the spatiotemporal evolution law of localized corrosion behavior can be obtained.

[0048] Figure 6 The results of the electrode electrochemical noise test of the X80 pipeline steel welded joint array electrode are used to measure the galvanic current and galvanic potential. The working electrode for this measurement is the electrode with channel number 22, which is the electrode with the largest galvanic current in the previous electrode array test results.

[0049] The above embodiments are used to explain the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A testing method for an electrochemical noise testing system, applied to a system comprising a first digital multimeter, a second digital multimeter, a weak current amplifier, a reference electrode, a working electrode, and a counter electrode, wherein the working electrode and the counter electrode are connected to two current input measurement terminals of the weak current amplifier; the two voltage output terminals of the weak current amplifier are connected to two voltage input measurement terminals of the first digital multimeter; and the array-type working electrode and the counter electrode are connected to the two current input measurement terminals of the weak current amplifier via a high-speed matrix switching switch. The array-shaped working electrodes and the reference electrodes are connected to the two voltage input measurement terminals of a second digital multimeter via a high-speed matrix switch. The method includes: The current noise is measured based on the output voltage of the first digital multimeter, and a current noise curve is generated. Based on the output voltage of the second digital multimeter, a potential noise measurement is performed synchronously with the current noise measurement to generate a potential noise curve; Based on the current noise curve and the potential noise curve, real electrochemical noise data is generated, which characterizes the local corrosion current density of multiple working electrodes to be measured. The working electrode with the highest local corrosion current density is identified as the target electrode, and the other working electrodes are used as counter electrodes for electrochemical noise measurement. Specifically, the process includes: S1, disconnecting the column channel Ci connected to the working electrode with the highest galvanic current from the first row channel R0 and connecting it to another second row channel R1 for current noise measurement; S2, measuring the current flowing between the first row channel R0 and the second row channel R1, which is the single current noise of the working electrode with the highest current under study; S3, disconnecting the column channel Ci from the second row channel R1 and connecting it to another third row channel R2 for potential measurement; S4, measuring the potential difference between the third row channel R2 and the fourth row channel R3 connected to the reference electrode, which is the single potential noise of the working electrode with the highest current under study.

2. The method as described in claim 1, wherein, The working electrode with the highest local corrosion current density is identified as the target electrode, and the other working electrodes are used as counter electrodes. Electrochemical noise measurements are performed, including: All working electrodes in the array are coupled, and the coupled array of working electrodes and reference electrodes are scanned for galvanic potential and galvanic current through a high-speed matrix switching switch to obtain the galvanic corrosion state and local corrosion current density of the target electrode.

3. The method as described in claim 1, wherein, The method further includes: Steps S1 to S4 are repeated at fixed time intervals M to achieve an electrochemical noise test at a fixed frequency of 1 / M.

4. The method of claim 1, wherein, The method further includes: The current noise measurement and the potential noise measurement are repeated periodically to update the real electrochemical noise data and the target electrode periodically.

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