CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

Chapter 6
Fig. 6.11b: Polarization study of uncoated and TiO 2 coated 304L SS in 8 M HNO 3 [22].
Conc.
Substrate condition
E corr
mV vs Ag/AgCl
I pass
µA/cm 2
I corr
µA/cm 2
E transpass
mV vs Ag/AgCl
1 M Uncoated 250 1.1 × 10 2 10 ×10 0 1100
1 M TiO 2 coated 360 10 × 10 0 5 ×10 -1 1250
8 M Uncoated 340 1.2 × 10 3 7 ×10 1 1025
8 M TiO 2 coated 550 5 × 10 2 4 × 10 1 1075
Table. 6.4: Average value of polarization parameters for uncoated and TiO 2 coated 304L SS in 1
M and 8 M HNO 3 [22].
Decrease in passive current density in 1 M nitric acid was two orders of magnitude while
in 8 M nitric acid it was one order of magnitude from uncoated to TiO 2 coated specimens. As
compared to Ti coated specimens, the passive current density for TiO 2 coated specimens was onefifth
in 1 M nitric acid, and half in 8 M nitric acid. The increase in transpassive potential