2.1. Sample preparation
Specimens of AISI-304 stainless steel (Acesita # 2B) of
size 5.0 cm × 1.0 cm × 0.1 cm were cut and their sides were
ground to remove burrs. They were degreased with acetone,
under ultrasonic vibrations, for 10 min at room temperature.
Previously to electropolishing the specimens were
cathodically polarized (0.1 A dm−2) in 1.0 mol L−1 HNO3
for 15 min. Then, after weighing, they were immersed in
aqueous 5.0 mol L−1 H2SO4 + 2.5 mol L−1 CrO3, at different
temperatures (30 ◦C ≤ θ ≤ 55 ◦C), and anodically polarized
(20 A dm−2 ≤ i ≤ 40 A dm−2) for different times (up to
30 min); afterwards, the specimens were weighed again. A
TCA/Tectrol 30 V–5 A power supply was used to control the
applied current and the bath temperature was controlled using
a thermostat.