Abstract
In this article, the potentiostatic passivation behavior of 2205 duplex stainless steel was investigated in oilfield-produced water with a focus on the variation of the passive layer stability with temperature. The obtained current-time transients were analyzed using wavelet transform to evaluate the passive layer deterioration at different time domains corresponding to the temperatures of 303 K, 313 K, 323 K, and 333 K (30 °C, 40 °C, 50 °C, and 60 °C). The results showed that the critical pitting temperature (CPT) of the 2205 alloy in the studied produced water was 333.2 K (60.2 °C). In addition, the optimum passivation of the material surface was obtained between 303 K and 313 K (30 °C and 40 °C). The passive layer deteriorated at about 323 K (50 °C) by penetration of chloride and subsequently entered into the transpassive region. Moreover, at 333 K (60 °C), the metastable pits converted to permanent or overlapped pits. Corrosion morphology confirmed the results obtained by wavelet analyses. In addition, microscopical studies of the alloy microstructure showed that both phases, i.e., austenite and ferrite, were attacked by corrosion, although it was more severe in ferrite.
Published Version
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