Tafel Purpose

Use the Tafel technique to obtain an accurate estimate of the corrosion rate and beta constants of a metal in a solution. Cell current is measured during a slow sweep of the potential. The sweep typically is from –250 to +250 mV relative to Eoc. A fit of the data to a standard model (Butler-Volmer Model) yields an estimate of Icorr which is used to calculate a corrosion rate. The graphical output of the experiment is a plot of log(current) versus potential. Analysis of the curve can yield the following types of information:

• Corrosion potential.
• Corrosion current and corrosion rate.
• Kinetic information (β coefficients) for the anodic and cathodic reactions.