CHEM02200704003 Nilamadhab Pandhy - Homi Bhabha National ...

Chapter 7
EC-SPM study on effect of temperature on the passive film morphology, stability and
degradation of 304L stainless steel in nitric acid medium.
The present work, and existing literatures gives qualitative and quantitative information
regarding the passive film property under in-situ condition in nitric acid medium at room
temperature condition. However, variation in temperature has major role on the passive film
properties such as nucleation and growth, formation and stability, change in donor-acceptor
density with change in activation energy, active-passive transition behaviour etc. As nucleation
and propagation of localized corrosion is related to the above mentioned properties, establishment
of a correlation between protective properties of the passive film as a function temperature is vital
in elucidating the many details of temperature effect on the corrosion behaviour of 304L SS in
nitric acid medium. EC-SPM can play a significant role in understanding the in-situ process of
nucleation and growth of passive film at different temperature condition. Morphological
investigation in association with other electrochemical, and surface analytical investigation can
bring out the “effect of temperature on the passive film and corrosion aspect of 304L stainless
steel in nitric acid medium”.
EC-SPM study of passive film of 304L stainless steel in mixed solution of nitric acid
containing oxidizing ions.
Oxidizing ions have greater influence on the corrosion resistance of austenitic stainless steel as
they shift the corrosion potential to the transpassive domain. Since corrosion potential shifts to
transpassive potential the passive film property as well as its dissolution rate also changes in the
presence oxidizing ions. Oxidizing ions also change the rate of cathodic and anodic reaction rates.
The rate of these reactions on the morphological consideration of the passive film has to be