Method and apparatus for measuring localized corrosion and other heterogeneous electrochemical processes

Abstract

An electrochemical method for measuring localized corrosion and other heterogeneous electrochemical processes is described. A multi-sensor electrode namely the wire beam electrode, integrated by coupling all its wire terminals together, is used to simulate a conventional one-piece metal electrode surface in electrochemical behavior. The working surface of the wire beam electrode is exposed to an electrolyte as a conventional one-piece electrode to allow heterogeneous electrochemical processes such as localized corrosion to occur. Electrochemical parameters at local areas of the wire beam electrode surface are detected by means of wires located at those areas. A zero resistance ammeter is inserted between each selected wire terminal and all other coupled wire terminals to measure the coupling current flowing into or out the selected wire, and thus a coupling current distribution map is produced. A high impedance voltmeter is used to measure the electrochemical potential of each temporarily uncoupled wire versus a reference electrode, and thus an electrochemical potential distribution map is produced. A polarization resistance measuring apparatus is used to measure the polarization resistance of each temporarily uncoupled wire, and thus a polarization resistance distribution map is produced. These electrochemical parameters and maps are used to determine the kinetics of heterogeneous electrochemical processes using equations described in this disclosure. This method and apparatus can be used to measure various forms of heterogeneous electrochemical processes such as localized corrosion, cathodic and anodic protection, electroplating, electro-machining, electrotyping and electrowinning.

Dependencies are inferred from the claim text.