Comportamento eletroquímico da cisteína e do difosfonato para o aço inoxidável 304 em 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 this 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 (AP), chronoamperometry (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 confi rmed by EIS and OM. [ABSTRACT FROM AUTHOR]