(a)
(b)
(c)
Figure 7:
Potentiodynamic polarization curves of steel immersed in aerated 0.1 mol L
−1
Na
2
SO
4
solution (pH 2.5) in the presence of tannin
(
1
)
and absence of tannin
(
2
)
for (a) 1 day, (b) 3 days, and 7 days.
