Electrochemical studies of the interface Fe/0.5 mol L(-1) H(2)SO(4) in the presence of benzotriazole and tolytriazole

The effect of benzotriazole (BTAH) and tolytriazole (TTAH) on the electrochemical behaviour of the Fe/0.5 mol L(-1) H(2)SO(4) interface at 25 degrees C was studied using cronopotentiometry, anodic and cathodic polarization curves and electrochemical impedance spectroscopy. BTAH and TTAH are inhibitors of anodic iron dissolution and the subsequent hydrogen evolution in 0.5 mol L(-1) H(2)SO(4) medium. Mass transport is an important step in the anodic process of inhibitive film formation. Electrochemical impedance spectroscopy was used to investigate the iron dissolution mechanism in the presence of the inhibitors and showed that BTAH and TTAH are adsorbed on the iron surface, thereby changing its dissolution mechanism in sulfate media. Starting from an iron dissolution model, it was possible to suggest two different mechanisms for iron dissolution in 0.5 mol L(-1) H(2)SO(4) containing BTAH or TTAH that involve a complex Fe(II)-inhibitor. (C) 2009 Elsevier B.V. All rights reserved

Study of electrochemical behavior of azoles for AISI 430 stainless steel in H(2)SO(4) 1 mol L(-1)

Corrosion is an undesirable process that occurs in metallic materials. Studied was the effect of inhibiting Benzotriazole (BTAH), Benzimidazole (BZM) and Indole in different concentrations-for the stainless steel (SS) AISI 430 in H(2)SO(4) mol The techniques employed this research were: anodic potenciostatic polarisation, electrochemical impedance spectroscopy, optical microscopy and scanning electron microscopy The curves of anodic polarisation showed that BTAH, BZM and Indol act as corrosion inhibitors for 430 SS, at concentrations of 1x10(-3) and 5x10(-4) mol L(-1) but do not inhibit corrosion for concentrations equal to or less than 1x10(-4) mol L(-1). The in-crease of the efficiency in relation to the inhibitory substances studied followed this order: Indol

Electrochemical behavior of the cistein and diphosfonate for stainless steel in media of HCl 1 mol L(-1)

Amino acids and self assembled monolayers (SAM`s) have been studied as to their inhibiting action on the corrosion of metallic materials. The objective of work is to study the electrochemical behavior of the cisteincisteine, the diphosfonate and the mixture of both in inhibiting the action of corrosion on stainless steel 304 in HCl 1 molL(-1). As the following techniques were used: open circuit potential (OCP), potenciostatic anodic polarization (A P), chronoamperomeny (CA), electrochemical impedance spectroscopy (EIS) and optical microscopy (OM). The results of CA showed that cisteine has a double effect, catalytic and inhibiting, in function of the immersion time of the metallic part in the electrolytic solution. AP curves have shown lesser current density for the system containing cisteine diphosfonate suggesting an inhibiting synergic action. These results have been confirmed by EIS and OM.