Abstract
The presence of hydrogen sulfide (H2S) in typical oilfield environments promotes hydrogen absorption and subsequent failure of high-strength steels by sulfide stress cracking (SSC). Plasma nitriding has recently been identified as a potential method to increase the resistance of the 17-4 PH to SSC, but there are still concerns about the corrosion resistance of the modified layer when it is exposed to H2S-containing environments. The aim of this study was therefore to evaluate the corrosion resistance of the 17-4 PH in typical oilfield environment. Samples were plasma nitrided at low (420° C) and high (500° C) temperatures and immersed in produced water with mixed H2S and CO2. The electrochemical data and SEM micrographs showed that there were no detrimental effects of the corrosion resistance when plasma nitriding was performed at low temperature (420° C). The enhanced resistance to localized corrosion of the nitride case obtained at this condition was attributed to the formation of a compound layer of mixed γ’–Fe4N/ε–Fe2-3N, the inner section being more corrosion resistant than the outer part.
Original language | English |
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Article number | 3273 |
Pages (from-to) | 1237-1245 |
Number of pages | 9 |
Journal | Corrosion |
Volume | 75 |
Issue number | 10 |
Publication status | Published - 5 Aug 2019 |