CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

Chapter 4
regions on the surface such as grain boundaries. Hence, the oxide boundaries slowly opened up as
potential increased showing aggressive attack around 1100 mV (Ag/AgCl) marked by arrows in
Fig. 4.9c-d.
4.2.4 X-ray photoelectron spectroscopy study
X-ray photoelectron spectroscopy analysis of the passive films formed at 1100 mV
(Ag/AgCl) in 0.1 M, 0.6 M, and 1 M nitric acid (Fig. 4.6d, 4.8d, 4.9d) along with specimens in as
polished condition are shown in Fig. 4.10-4.13. XPS results in aforementioned concentration, and
at 1100 mV are shown because characteristic change in passive film morphology was observed at
these concentrations. The results presented in Fig. 4.10-4.13 represent the high resolution spectra
of Cr2p 3/2 and O1s in as polished condition, and at concentrations of 0.1 M, 0.6 M, and 1 M nitric
acid. Binding energy shift was observed mainly for chromium (Cr2p 3/2 ) and oxygen (O1s) profiles
indicating changes in passive film composition. Figure. 4.10a-b represents the chromium, and
oxygen profile in as polished condition.
Intensity (Arbitrary units)
Cr 2P 3/2
(As polished)
Cr 0
Cr 2
O 3
582 580 578 576 574 572 570
Binding energy (eV)
Fig. 4.10a: XPS profile of Cr2p 3/2 in as polished 304L SS.