The potentiostatic measurements were made using a Solartron 1287 electrochemical
interface under control of CorrWare 2 software from Scribner Associates via a
desktop computer. A potentiostatic technique was used at the open circuit potential
(OCP) to measure the anodic current spikes for 30 min, after a typically short 150-s
equilibrium period to attain the OCP with measurements being made at a frequency
of 10 Hz. The potentiostatic measurements were conducted in a Faraday cage to reduce
external electrical noise and a three-electrode electrochemical cell incorporating
a standard calomel reference electrode housed in a Luggin capillary was employed
along with two carbon rod counter electrodes. The OCP was decided upon as the
measurement potential so as to keep the corrosion behaviour as close as possible
to that of a freely corroding electrode.