Effect of SO42−and Cl−anionic attack on the localized corrosion resistanceand morphology of 409 ferritic stainless steel

Loto, R. T. (2019) Effect of SO42−and Cl−anionic attack on the localized corrosion resistanceand morphology of 409 ferritic stainless steel. Results in Physics, 12. pp. 738-742.

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Abstract

The corrosion polarization behaviour and optical characterization of 409 ferritic stainless steel (SS409) in 0.25 MH2SO4(at specific NaCl concentration), 0.375 M H2SO4and 0.5 M H2SO4was evaluated with potentiodynamicpolarization technique, open circuit potential measurement and optical microscopy characterization. Resultsshowed the SS409 corrosion rate is proportional to the concentration of SO42−and Cl−anions in the electrolyte.At 0.25 M H2SO4, SS409 corroded at a rate of 7.29 mm/y; addition of 0.125% NaCl accelerated the corrosion rateto 16.75 mm/y coupled with a corresponding increase in corrosion current density from 6.71 × 10−4Acm2to3.08 × 10−3Acm2. Further increase in Cl−anion concentration to 0.75% NaCl increased the corrosion rate to19.49 mm/y. At 0.25 M H2SO4the pitting current value is 1 × 10−4A, this value increased to 1.03 × 10−4Aat0.25 M H2SO4(0.125% NaCl) and 8.40 × 10−4A at 0.25 M H2SO4(0.5% NaCl). Beyond 0.5% NaCl, passivationbehavior was completely absent. Intergranular cracks, large macro-pits and numerous micro-pits were observedfor SS409 from 0.25 M H2SO4(0.75% NaCl) due to Cr depletion and dissolution of inclusions. SS409 from 0.5 MH2SO4showed the presence of deepened intergranular cracks, shallow pits and a deteriorated surface due to theaction of SO42−anions. The morphology of SS409 in 0.25 M H2SO4+ 0.125% NaCl showed slight deteriorationin addition to enlarged micro-pits

Item Type:	Article
Subjects:	T Technology > T Technology (General) T Technology > TJ Mechanical engineering and machinery
Divisions:	Faculty of Engineering, Science and Mathematics > School of Engineering Sciences
Depositing User:	Mrs Hannah Akinwumi
Date Deposited:	28 Aug 2020 14:02
Last Modified:	28 Aug 2020 14:02
URI:	http://eprints.covenantuniversity.edu.ng/id/eprint/13554

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