CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

Chapter 5
unimplanted as well as nitrogen implanted specimens did not reveal any active-passive behaviour.
After cathodic region it slowly translated into passive region followed by transpassive regime.
Potential (V) vs Ag/AgCl
1.2
1.0
0.8
0.6
0.4
0.2
304L SS
1x10 15 N + /cm 2
1x10 16 N + /cm 2
1x10 17 N + /cm 2
2.5x10 17 N + /cm 2
0.0
-0.2
10 -4 10 -2 10 0 10 2 10 4
Log I (µA/cm 2 )
Fig. 5.7: Potentiodynamic polarization of unimplanted and nitrogen implanted
304L SS in 1 M HNO 3 [21].
The quantitative values for corrosion related parameters obtained from the polarization
plots are mentioned in Table. 5.1. It is evident from Table. 5.1 that there was threefold increase in
corrosion potential (E corr ), simultaneous decrease in corrosion current density (I corr ) by two order
of magnitude, reduction in passivation current densities (I pass ) by one order, and marginal increase
in transpassive potential (E transapass ) by 10 mV vs. Ag/AgCl from unimplanted to highest dose of
nitrogen implantation. The maximum standard deviation for all the corrosion related parameters
such as E corr , I corr , I pass and E transpass mentioned in Table. 2 are within ± 15 mV vs. Ag/AgCl, ±
5×10 -3 µA/cm 2 , ± 3 µA/cm 2 , and ± 7 mV vs. Ag/AgCl, respectively [21].