Assessment of the corrosion susceptibility of 434 ferritic stainless steel in chloride-sulphate solution
No Thumbnail Available
Date
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
The corrosion polarization behaviour of 434 ferritic stainless (434ST) was studied in
1MH2SO4 at 0.25%to 2%NaCl concentration through potentiodynamic polarization techniques
and open circuit potential analysis. Results showed corrosion rate of 434ST at in 1 M H2SO4
solution at 0% NaCl concentration is 5.51 mm/y. However, at 0.25% NaCl concentration
corrosion output decreased to 1.31 mm/y due to competitive adsorption mechanism with
dissolved O2 atoms. Increment in NaCl concentration causes increase in corrosion rate till 1%
NaCl concentration at 5.97 mm/y. After 1%NaCl concentration, the corrosion of 434ST attained
threshold deterioration mechanism with values varying between 6.20 mm/y and 6.56 mm/y. Shift
in corrosion potential plot with respect to 434ST at 0% NaCl concentration indicates anodic
corrosion and passivation mechanism on the steel surface which was also proven from the anodic
Tafel slope values. Open circuit potential plots showed plots at 2% NaCl concentration showed
the least thermodynamic tendency to corrode with the strongest shift to electropositive potentials
which culminated at -0.439 V at 5400 s of observation. The plot at 0% NaCl solution exhibited
the most electronegative plot configuration by reason of the deteriorating reaction of SO4
2- on
the steel.
Keywords
TJ Mechanical engineering and machinery