Apoio à seleção de materiais resistentes à corrosão por técnicas eletroquímicas

Abstract

As important fields of oil production in Brazil are maturing, more water produced will be generated by the oil industry. The water produced can be much more aggressive in terms of corrosion than sea water, presenting high levels of chloride and carbon dioxide. The water produced in addition to bringing risks in terms of corrosion our equipment, constituting common components for the environment, therefore it is necessary that this water undergoes a treatment before disposal. From this scenario, a need arises for a selection of materials that guarantee a good performance of water treatment systems produced. Although there are many studies evaluating the corrosioni resistance of stainless steels in seawater medium, the resistance of materials in produced water has not been fully investigated. An indicator of the corrosion resistance of stainless steel is the Pitting Resistance Equivalent Number (PREN), However, this parameter is only function of the composition of the alloy and does not take into consideration variations of the corrosive medium. This study investigates a correlation between some parameters obtained by electrochemical techniques and NERP. An evaluation of austenitic stainless steels 304, 316L and 904L and duplexes 2205 and 2507. Varying a concentration of chloride, CO2 and temperature. The parameters were obtained from the techniques of anodic polarization and electrochemical impedance spectroscopy. There was observed a difference in the classification of the alloys using the NERP and using as criterion electrochemical parameters.