The principle of the scanning reference electrode technique (SRET) is shown in this Demonstration. SRET is an electrochemical technique that uses a reference electrode as a probe to investigate local interface processes, including localized corrosion, galvanic corrosion, and potential distribution. The potential of the probe is a function of the relative position between the probe (electrode B) and the sample surface (electrode C).
The principal components of SRET are three electrodes:
• a fixed reference electrode A,
• a movable reference electrode B, a fine-tipped Luggin probe mounted on a position controller, and
• the substrate C.
You can control the radial distance or the separation distance of the probe B. The tip should be as close to the substrate as possible for maximum sensitivity. The closer the probe is positioned, the higher the measured signal (probe voltage from snapshot 1 to snapshot 3).