Effect of carbon dioxide and temperature on passive film parametersof superduplex stainless steel

Materials Research

Emandro Vieira Da Costa²  Thiago José Mesquita¹  Ariane Ferreira²  Ricardo Pereira Nogueira¹  Ivan Napoleão Bastos² 

[1] ,Rio de Janeiro State University Polytechnic Institute Nova Friburgo RJ ,Brazil

关键词: superduplex stainless steel;    electrochemical impedance;    equivalent circuit;    carbon dioxide;    heat-treatments;   

DOI  :  10.1590/S1516-14392013005000088

来源: SciELO

【 摘 要 】

Superduplex stainless steel has been frequently employed in new sites of Brazilian Pre-Salt. In these environments, chloride concentration, temperature and carbon dioxide are normally present in higher levels than those at sea water at room temperature. In these conditions, it is expected that the passive films of stainless steel also show modifications. To better understand such modifications, samples of superduplex stainless steel UNS S32750 were submitted to electrochemical impedance measurements in brine media, at two temperatures and under presence/absence of carbon dioxide. The electrochemical impedance results were initially tested using the Kramers-Kronig transform and subsequently fitted by equivalent circuit employing constant phase elements - CPE. Moreover, to quantify the effect of each factor (temperature, chloride, carbon dioxide and microstructure) on the equivalent circuit, their parameters were tested applying statistical analysis. Significant effect of carbon dioxide and temperature was found on related parameters of passive film for heat-treated samples.

【 授权许可】

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