The experimental set-up for surface modification was similar to the system shown in Fig. 4, which
consisted of an electrolytic cell with a magnetic stirrer and a high-power unipolar pulsed DC voltage
source with a frequency of 60 Hz. The temperature of the electrolyte was maintained at 20 °C with an
immersed coiled stainless steel tube connected to a thermostatted bath using a recirculation pump.