Three-electrode array local electrochemical information testing system and testing method

Abstract

The invention provides a local electrochemical information testing system of a three-electrode array, which includes a concentric three-electrode array electrically connected in sequence, a high-speed switch and an electrochemical workstation. The concentric three-electrode array includes several concentric three-electrode units, Adjacent concentric three-electrode units are separated by insulating materials; the concentric three-electrode units include annular auxiliary electrodes, solid-state reference electrodes and wire-shaped working electrodes, and the annular auxiliary electrodes and solid-state reference electrodes are both In a ring shape, the wire-shaped working electrode is located in the solid-state reference electrode, and the wire-shaped working electrode and the solid-state reference electrode are separated by an insulating material; the solid-state reference electrode is located in the ring-shaped auxiliary electrode. Using this system is more convenient to comprehensively obtain interface electrochemical information such as galvanic current, corrosion potential, corrosion current density, and electrochemical impedance spectroscopy under electrode coupling / uncoupling state. At the same time, the invention also provides a testing method of the system.

Description

technical field [0001] The invention relates to the field of electrochemical testing, in particular to a three-electrode array local electrochemical information testing system and testing method. Background technique [0002] In the electrochemical test system, it is not only necessary to study the overall information of the entire electrode surface, but also gradually expand to the characterization of local electrochemical information on the electrode surface. For example, localized corrosion of metals is closely related to the electrochemical process at the interface, and the distribution characteristics of local electrochemical parameters such as interface potential, current density, and impedance are very important for studying the distribution characteristics and mechanism of localized corrosion. Classical corrosion electrochemical methods such as cyclic voltammetry, polarization curves, electrochemical impedance spectroscopy, etc. can only obtain the electrochemical in...

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Problems solved by technology

There are certain limitations in the application conditions and obtained information of the above test methods. Only certain aspects of the electrochemical test system, such as potential, current, and impedance, can be obtained, and some of them are indirect information. Electrochemical reaction leads to the test of electrolyte electric field gradient. The current density distribution and micro-area impedance obtained respectively are not the reaction information of the substrate material. SKP is a test based on the work function of the electrode surface, and the Kelvin potential is directly measured, which is also different. Potential at the electrode / solution interface

[0004] However, in the more complex gas, liquid and solid multi-phase inhomogeneous test system, due to the solid component, it is impossible to use the micro-area electrochemical technology of scanning mobile micro-probe type such as SVET and LEIS

Conventional array electrode technology (EA) can only obtain corrosion potential and galvanic current distribution information, but cannot obtain local current, impedance and other data, and the test information is not comprehensive and rich.

Moreover, in a system with relatively large resistivity and dispersed electrolyte, the potential accuracy measured by the array electrode is also affected by the ohmic potential drop of the corrosive medium and the dispersion of the electrolyte.

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