A STEM Examination of the Localized Corrosion Behavior of a Duplex Stainless Steel

CORROSION ◽  
1980 ◽  
Vol 36 (5) ◽  
pp. 246-251 ◽  
Author(s):  
P. E. MANNING ◽  
C. E. LYMAN ◽  
D. J. DUQUETTE
Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 529 ◽  
Author(s):  
Federica Zanotto ◽  
Vincenzo Grassi ◽  
Andrea Balbo ◽  
Fabrizio Zucchi ◽  
Cecilia Monticelli

This paper reports the effects of thermal aging between 650 and 850 °C on the localized corrosion behavior of lean duplex stainless steel (LDSS 2404). Critical pitting temperature (CPT) and double loop electrochemical potentiokinetic reactivation (DL-EPR) tests were performed. The localization of pitting attack and intergranular corrosion (IGC) attack after DL-EPR was investigated by optical (OM) and scanning electron microscopy (SEM) and by focused ion beam (FIB) coupled to SEM. Thermal aging caused the precipitation of mainly chromium nitrides at grain boundaries. Aging at 650 °C or short aging times (5 min) at 750 °C caused nitride precipitation mainly at α/α grain boundaries as a result of fast diffusion of chromium in this phase. Aging at 850 °C or aging times from 10 to 60 min at 750 °C also allowed the precipitation at the α/γ interface. Nitrides at γ/γ grain boundaries were observed rarely and only after long aging times (60 min) at 850 °C. Electrochemical tests showed that in as-received samples, pitting attack only affected the α phase. Conversely, in aged samples, pitting and IGC attack were detected close to nitrides in correspondence of α/α and α/γ grain boundaries depending on aging temperatures and times.


2015 ◽  
Vol 53 (7) ◽  
pp. 464-473 ◽  
Author(s):  
Soon-Tae Kim ◽  
In-Sung Lee ◽  
Kyeong-Ho Kong ◽  
Yong-Soo Park ◽  
Jong-Hoon Lee ◽  
...  

2014 ◽  
Vol 513-517 ◽  
pp. 189-192 ◽  
Author(s):  
John Gerald Odhiambo ◽  
Li Zhang ◽  
Tao Liu ◽  
Li Hua Dong ◽  
Yan Sheng Yin

The corrosion behavior of duplex stainless steel immersed in nutrient-rich simulated seawater without deep sea bacteria and with deep sea bacteria (Erythrobacter pelagi sp.nov) was studied. The effect of chloride ions and presence of deep sea bacteria on corrosion resistance was investigated. The occurrence of localized corrosion (Viz. pitting and crevice corrosion) was examined using visual inspection and SEM-EDX. Electrochemical impedance spectra were used to study the effects of deep sea bacteria on duplex stainless steel and inferences were made. Most significantly was the reduction of pitting resistance potential with increase in exposure time.


2021 ◽  
Vol 63 (6) ◽  
pp. 505-511
Author(s):  
Songkran Vongsilathai ◽  
Anchaleeporn Waritswat Lothongkum ◽  
Gobboon Lothongkum

Abstract A new duplex 25Cr-3Ni-7Mn-0.66 N alloy was prepared in a vacuum arc re-melting furnace and characterized by metallographic and EPMA methods. Its corrosion behavior was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and a Mott-Schottky (M-S) analysis in artificial seawater at room temperature and compared with those of super and normal commercial duplex stainless steel (SDSS and DSS). No significant difference in the open circuit potentials and pitting potentials was observed. Its passive film current density lies between those of SDSS and DSS. This was confirmed by EIS analysis. A pit attack was observed on the δ-phase for all duplex samples, because the PREN16 of the δ-phase was lower than that of the γ-phase. From the Mott-Schottky analysis, the passive films were found to be composed of bi-layer structures, a p-type semiconductor inner layer, and a n-type semiconductor outer layer. The degree of defect as well as the effect of nitrogen in passive film layer are discussed with respect to the point defect model.


CORROSION ◽  
10.5006/3746 ◽  
2021 ◽  
Author(s):  
Víctor Vargas ◽  
Apolinar Albiter-Hernandez ◽  
Marco Dominguez Aguilar ◽  
Gerardo Altamirano-Guerrero ◽  
Cuahtemoc Maldonado

The effect of weld passes and single V grove designs, on the corrosion resistance of dissimilar welds of a low alloy steel and a super-duplex stainless steel, was studied in synthetic brine. Welds were manufactured in argon by gas tungsten arc (GTA) technique and joined by a high nickel wire of super-duplex stainless steel. Samples of weld regions were characterized by composition scans, electrochemical measurements, micro-hardness and scanning electron microscopy. In X52/ER2594, a transition region (TR) of grain boundaries type II and a band of martensite were formed. The base metal of X52 underwent the highest corrosion rate and localized corrosion occurred in the heat affected zone. Interface ER2594/25Cr7Ni and 25Cr7Ni showed the presence of pitting near intermetallics.


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