Impedance spectroscopy (EIS) is used to evaluate the inhibiting performances of phenylthiourea in the corrosion of steel in 1 N sulphuric acid. The values of the percent Inhibiting Efficiency obtained by EIS agree with those obtained by solution analysis and polarization curves. To evaluate the equivalent circuit related to the corrosion process a mathematical treatment of EIS data is proposed. For a better fitting time constant dipersion is introduced. At 1 mM phenylthiourea concentration, the equivalent circuit is characterized by a Resistance (Ra) in parallel to a Capacitance (Cdl), in parallel to which there are two RC series arms, which correspond to two adsorbed intermediates, which affect the anodic process kinetics. One intermediate can deal with adsorbed hydroxyl, the other with adsorbed inhibitor molecule.
Impedance measurements on Armco iron in acid solution inhibited by S-containing additives
FRIGNANI, Alessandro;TRABANELLI, Giordano
1989
Abstract
Impedance spectroscopy (EIS) is used to evaluate the inhibiting performances of phenylthiourea in the corrosion of steel in 1 N sulphuric acid. The values of the percent Inhibiting Efficiency obtained by EIS agree with those obtained by solution analysis and polarization curves. To evaluate the equivalent circuit related to the corrosion process a mathematical treatment of EIS data is proposed. For a better fitting time constant dipersion is introduced. At 1 mM phenylthiourea concentration, the equivalent circuit is characterized by a Resistance (Ra) in parallel to a Capacitance (Cdl), in parallel to which there are two RC series arms, which correspond to two adsorbed intermediates, which affect the anodic process kinetics. One intermediate can deal with adsorbed hydroxyl, the other with adsorbed inhibitor molecule.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
