Electrochemical behaviour of duplex stainless steels in caustic environment

Corrosion Behavior of Duplex and Lean Duplex Stainless Steels in Pulp Mill

“…They studied the role of alloying elements in DSS in these environments by analyzing the polarization behavior of pure Fe, Cr, Ni and Mo, and DSS UNS S32205. The increase in corrosion rates of DSS with sulfide addition can be related to the presence of sulfur in the passive layer and the formation of metal-sulfur compounds thatare less protective than the oxide film 14 . The S32205 steel was found to be most susceptible to general corrosion and the S32304 steel had the lowest corrosion rates in a sulfide caustic environment.…”

“…The scheme of the main operation of the chemical recovery cycle is shown in Figure 1. Moreover, the white liquor is considered the most aggressive of the alkaline pulping liquors 14 . Duplex stainless steel (DSS) has been used as a material of construction in the pulp and paper industry for the past 35 years due to its excellent corrosion resistance and high mechanical strength allowing for thickness reduction in equipment.…”

“…In the pulp and paper industry, carbon steel pulp mill equipment, like digesters, storage vessels, have been showed general corrosion and stress corrosion cracking 14,[23][24][25] . Singh and Anaya evaluated the corrosion behavior of carbon steel (A 516-Gr 70), AISI 304 and 316 stainless steels, and two DSSs (UNS S32304, UNS S32205) in black liquor produced by pulping five wood species in a synthetic liquor.…”

“…The organic compounds in the black liquor were found to play a major role in steel corrosion, and the DSSs showed a high corrosion resistance in all tested black liquors 22 . Corrosion resistance of DSS in white liquor has been widely studied 14,[21][22][23] . The corrosion properties and electrochemical behavior of different DSSs (UNS S32304, UNS S32205, and UNS S32101) in high pH caustic and alkaline sulfide solutions at different temperatures were investigated by Bhattacharya and Singh 14 .…”

“…Corrosion resistance of DSS in white liquor has been widely studied 14,[21][22][23] . The corrosion properties and electrochemical behavior of different DSSs (UNS S32304, UNS S32205, and UNS S32101) in high pH caustic and alkaline sulfide solutions at different temperatures were investigated by Bhattacharya and Singh 14 . They studied the role of alloying elements in DSS in these environments by analyzing the polarization behavior of pure Fe, Cr, Ni and Mo, and DSS UNS S32205.…”