Constant currents for experiments in the Hull and ‘beaker’ cells
were obtained using a laboratory dc power supply from ISO-TECH
model IPS2303. The flow cell experiments were controlled with an
EG & G Potentiostat/Galvanostatmodel 263A and output datawere
recorded and analysed using EG & G Power Suite Software together
with in-house software.
Scanning electron micrographswere obtained using two instruments.
Samples from the Hull cell were analysed using a JEOL SEM
model JSM-5910 using an accelerating voltage of 15 kV. The other
samples were analysed using a Phillips Environmental SEM model
XL30 again using an accelerating voltage of 15 kV. The sampleswere
mounted at 90◦ to the beam.