Using Electrochemical Impedance Spectroscopy Sinusoidal Potential Amplitude to Assess the Efficiency of Niobium Oxide Based Organic Coating in Oil Wells Produced Water

摘要

The oil industry coexists with damages caused by corrosion of materials in almost all areas of activity.Recent discoveries in Brazil of potential oil reserves at deeper waters, commonly named re-salt oillayer may represent severe conditions leading to the need in developing new materials andtechnologies that meet unfavorable prospection demands. In this context, the corrosion protectioncharacteristic of an organic coating based on niobium oxide immersed in water produced by oil wellswas evaluated. The evaluation of the coating was carried out by means of electrochemical impedancespectroscopy technique (EIS). Results showed that only with the application of high voltageamplitudes of 350 mV over the OCP it was possible to decrease dispersion in EIS data, with nodegradation or delamination of the coating. Despite this, at high voltage sinusoidal signal and raisingthe agressivity of the medium, it was observed an increase in the corrosion mechanisms leading tolower impedance module values at longer exposure time (144 days), indicating the need foroptimization of sinusoidal voltage amplitudes according with the nature, thickness and resistivity ofthe coating applied.