CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

Chapter 4
The chromium, and oxygen profile for 304L SS passivated in 0.6 M nitric acid are shown
in Fig. 4.12a-b. The chromium profile for 304L SS passivated in 0.6 M nitric acid showed the
presence of Cr(OH) 3 peak around 577.7 eV, however the intensity was much less as compared to
Cr 2 O 3 around 576.8 eV (Fig. 4.12a). Similarly, the oxygen profile for 304L SS passivated in 0.6 M
nitric acid also showed peak for Cr(OH) 3 , but the intensity of Cr 2 O 3 peak around 531.1 eV was
much higher as compared to Cr(OH) 3 peak (Fig. 4.12b). The chromium, and oxygen profile for
304L SS passivated in 1 M nitric acid are shown in Fig. 4.13a-b. At 1 M nitric acid concentration
the peak positions for chromium and oxygen were by and large similar to that of as polished
condition. Chromium profile showed the presence of Cr 2 O 3 , and elemental chromium at their
characteristics binding energy (Fig. 4.13a). However, no detectable peak for chromium hydroxide
was observed in chromium region. The oxygen profile revealed the presence of Fe 2 O 3 , Cr 2 O 3 and
presence of Cr(OH) 3 (Fig. 4.13b) at their usual position as seen in case of as polished specimen.
Intensity (Arbitrary units)
Cr2p 3/2
(0.6 M HNO 3
)
Cr 0
Cr 2
O 3
Cr(OH) 3
580 578 576 574 572
Binding energy (eV)
Fig. 4.12a: XPS profile of Cr2p 3/2 of 304L SS passivated in 0.6 M HNO 3 .