Dissolution Behavior of α and γ Phases of a Duplex Stainless Steel in a Simulated Crevice Solution

Abstract

The purpose of this study is to clarify corrosion mechanism of a duplex stainless steel (DSS) through dissolution behavior of a ferritic phase and austenitic phase, respectively. A single phase specimen ([D] or [J] phase specimen) which has chemical composition of each phase of a DSS was prepared by preferential dissolution of the DSS, and dissolution behavior of each phase specimen was investigated. The [D] specimen showed a less-noble corrosion potential compared to the [J] specimen. The change of the corrosion potential of the DSS was located somewhere between those of each phase specimen. The [D] specimen showed a lessnoble active peak compared to the [J] specimen. The current density value of the DSS was located between the current values of each phase specimen. It was clearly shown that the corrosion mechanism of a DSS could be described through the dissolution behavior of single phases such as D phase and J phase.

Time-dependent in situ measurement of atmospheric corrosion rates of duplex stainless steel wires

“…33,35,36,41,42,46,47 Similar observations of selective attack on the ferrite phase have also been reported on lean DSS 2101 and 2202. 2,48,49 In lean DSS 2202, the measured corrosion depthto-area ratio was low, indicating a strong tendency for repassivation of active corrosion sites.…”

“…38 Selective dissolution of the ferrite phase may be more likely in DSS due to the lower corrosion potential of the ferrite than that of the austenite in chloride-containing environments. 36,[39][40][41][42][43] However, selective attack of the austenite may also be possible if the oxidising power of the electrolyte is sufficiently high, where the ferrite remains passive. [39][40][41][42] The extent of surface corrosion and the dissolved volume slightly increased with exposure time, as shown in Fig.…”

Characterization of 475°C Embrittlement of Duplex Stainless Steel Microstructure via Scanning Kelvin Probe Force Microscopy and Magnetic Force Microscopy

“…The pH of the solution is estimated to be around 0, which seems to result in the preferred dissolution of austenite, compared to the ferrite. 61,62 Electro-polishing at high applied voltages typically leads to homogeneous dissolution and, therefore, it is unlikely that the surface was altered. Another reason could be the slight difference in hardness of the ferrite and austenite, which can lead to proportionally higher material removal rate of the austenite during grinding and polishing due to its softer structure.…”

Double-loop electrochemical potentiokinetic reactivation behaviour of continuously cooled SUS329J4L duplex stainless steel

“…The fractured surface appearances showed ductile fracture at 1.0 K s −1 , quasi-cleavage fracture at 0.5-0.1 K s −1 and Figure 4. In the forward scanning, two current peaks, which correspond to the active dissolution from the α phase (about −0.34 V) and the γ phase (about −0.25 V) appeared [23][24][25][26]. In the active zone, both general corrosion from the entire surface and selective corrosion from grain boundaries and chromium-depleted regions might occur.…”