Coupling of electrochemical techniques to study copper corrosion inhibition in 0.5molL−1 NaCl by 1-pyrrolidine dithiocarbamate

Abstract

In this work, as for the preliminary step to the protection of Al 2xxx alloys, the anticorrosion effect of environmentally friendly 1-pyrrolidine dithiocarbamate (PDTC) on Cu was investigated by combining various electrochemical methods in addition to SEM-EDS analyses and gravimetric measurements. The Cu / PDTC system was used as a model to simulate the inhibition of Cu-rich particles contained in Al 2xxx alloys. The corrosion test solution was 0.5 mol L-1 NaCl in presence of 10-4 , 10-3 , or 10-2 mol L-1 PDTC. The immersion time of the copper electrode was extended generally up to 24 hours. By EQCM measurements, a marked protective effect of PDTC was observed for the highest PDTC used, and corroborated by voltammetry and EIS measurements. The cathodic reduction under constant current allowed determining the corrosion products remaining on the copper surface in terms of electrical charge. The protective effect of PDTC was explained by the formation of highly stable compounds on the copper surface, which decreases the rate of both anodic dissolution and oxygen reduction reaction.

Effect of 1-pyrrolidine dithiocarbamate on the galvanic coupling resistance of intermetallics – Aluminum matrix during corrosion of AA 2024-T3 in a dilute NaCl

“…This result shows that during immersion at open circuit, in the solution containing PDTC, stable and adherent products form at the Cu surface in good agreement with the results obtained in 0.5 mol L À1 NaCl [38]. Fig.…”

“…Beyond 45 h of immersion, the slope Dm/Dt approaches zero. A similar behavior was observed for Cu [38] and the rise in mass was attributed to the formation of CuCl layer stabilized by PDTC leading to an interface more resistant to corrosion damages.…”

“…This element in the surface layer is evaluated to be about 18% in an atomic percentage. By analogy with the results obtained with the system Cu/PDTC in 0.5 M NaCl [38], one may suggest that even at low content of NaCl, PDTC strongly interacts with the Cu surface to stabilize the Cu I products, mainly Cu 2 O and CuCl. In the 0.5 M NaCl environment, it was found that the surface layer of Cu I products is stabilized sufficiently to strongly hinder the ORR.…”

“…This beneficial effect likely results from the interaction of PDTC with the Cu-rich particles since other studies [35][36][37] have demonstrated that the dithiols inhibit the ORR on copper in neutral chloride solutions. A more complete study of the system Cu/PDTC in a chloride solution [38] was realized to help understanding the effect of PDTC on localized corrosion inhibition of AA 2024-T3 alloy. The results obtained on copper showed that PDTC is a good mixed inhibitor for Cu in 0.5 mol L À1 NaCl.…”

Influence of 2,2′‐bipyridine on oxidative dissolution of iron monosulfide

“…The impedance parameters derived from Nyquist plots are given in Table . According to Qafsaoui et al ., in the case of redox processes, polarization resistance (the sum of R ct and R sl ), but not the charge transfer resistance, is better correlated with i corr . Polarization resistance increases from 1181 (0 mM 2,2′‐bipyridine) up to 1596 Ω (0.5 mM 2,2′‐bipyridine).…”