Scanning Micropipette Contact Method Images Corrosion Related Electrochemical Activities on Al Alloy Surface

摘要

Scanning micropipette contact method (SMCM) is powerful in mapping electrochemical activities of a surface at a high spatial resolution and revealing the surface heterogeneities. Al alloys is heterogeneous in composition resulting in different corrosion rates over the surface. By approaching the electrolyte solution filled micropipette to the sample, a micro electrochemical cell can be formed on the predefined location upon the droplet at the end of pipette touches the surface, where electrochemical measurements including polarization test and Ecorr vs time could be conducted locally. SMCM maps can clearly reveal the locations and electrochemical properties of the inclusions which agree with the SEM images and EDX analysis.