Figure 1. Optical micrograph of laser ablated,
coil coated, galvanized steel.

The Scanning Vibrating Electrode Technique (SVET) operates with a non-intrusive scanning, vibrating probe measuring and mapping the electric field generated in a plane above the surface of an electrochemically active sample. This enables the user to map and quantify local electrochemical and corrosion events in real time.

Applications of the scanning vibrating probe include: -

• Efficiencies of corrosion inhibitors
• Characterisation of grain boundaries
• Corrosion investigation of biomaterials
• Spatial distribution of pH and ionic currents
• Non-invasive measurement of bioelectric currents
• Surface Chemistry of Biomaterials

The SVP370 vibrating probe system provides increased electrical sensitivity as well as enhanced system stability. Localised corrosion events of less than 5µA/cm2 can be measured with this extremely sensitive technique.

The probe vibration is controlled by a piezoceramic displacement device allowing vibration amplitudes from 1-30 µm (perpendicular to the sample surface).

Time resolved SVET area maps

It is an ac technique, thus, high system sensitivity is achieved via a differential electrometer in conjunction with an integrated lock-in amplifier.

All system parameters, including the xyz scanning mechanism, piezo actuator, and lock-in amplifier are controlled via a PC under the user friendly Windows™ operating system.

The topology of the sample can be measured by Optical Surface Profiling technique (OSP370) and is recognized by the M370 software.  Any of the experiments that can use Height-Tracking (SVP, SKP, SECM, SDS) can use this information to move the probe relative to the topography of the sample.

The figure illustrates a SVP probe tracking a metallic surface, where the probe’s position across the surface is depicted by the curved transparent surface.

The SVP370 can now be supplied with the PG580R option to allow the user to perform localised measurements whilst controlling the potential or current applied to the sample surface. The PG580R potentiostat is controlled by the M370 software which can be purchased with all the routine electrochemistry experiments (EChem370) and corrosion techniques (ECorr370).