While there is not a clear trend between Ecorr and
PANI loading in the case of LS1 and LS2 dopants, a clear decrease by
as much as −200 mV is observed when PANI–BS content increases
from 1.5% to 3%.
The differences in the current density at Ecorr clearly
demonstrate that PANI pigments reduce the general corrosion rate
for the whole period of testing (i.e., 40 days).
For BS as a dopant, a low loading of PANI, i.e., 0.5%, gives the best inhibitive properties.
An opposite trend is observed with the LS dopants, especially with PANI–LS2.
The coatings with 0.5% PANI–BS, 1.5% PANI–LS1 and 3%
PANI–LS2 all show about the same protective efficiency: the current
density at Ecorr for the steel coated with these coatings was
decreased by about two orders of magnitude as compared to the
steel coated with the paint without PANI.