In situ study of selective dissolution of duplex stainless steel 2205 by electrochemical scanning tunnelling microscopy

• Selective dissolution of duplex stainless steel 2205 in acidic chloride solutions was studied in situ by electrochemical scanning tunnelling microscopy (STM). In 0.05 M H2SO4 + 1 M NaCl, no appreciable active dissolution was observed by in situ STM imaging at the corrosion potential (E-corr), but at potentials higher than E-corr + 1000 mV some selective dissolution at the austenite-ferrite boundary region occurred. In 4 M H2SO4 + 1 M HCl, STM images revealed active dissolution of ferrite grains at around E-corr + 50 mV. Dissolution of austenite grains started to occur at around E-corr + 150 mV, exhibiting steps of submicron scale on the edges.

Nyckelord

duplex stainless steel

in situ

local

electrochemical scanning tunnelling microscopy

selective dissolution

single-crystal surfaces

tunneling-microscopy

pitting corrosion

localized corrosion

spectroscopy

electrodes

nitrogen

xps

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