A new methodology to study in-situ the pitting corrosion of stainless steels at high temperature and high pressure (HT/HP) was developed. This methodology allowed the real-time in-situ anodic polarization while determining the sites for pit initiation in UNS S32305 (22% Cr Duplex Stainless Steels), in chloride containing environments with additions of H2S and CO2 at high temperature and pressure. The methodology allowed measurements at two temperatures 40°C (and 582 psi) and 180°C (and 752 psi). This methodology allowed the in-situ imaging of metastable pitting as well as stable pitting under different conditions. Pitting corrosion developed in inclusions (5-10 micrometer or larger); which are mainly composed of intermetallic particles containing significant amounts of B, N, O, Mg, Al, S, Ca and C.

Subject
Scanning electron microscopy, Electric current, Materials, Cathodic current, Polishing, Anode surfaces, Pitting, Ferrite, Anodic polarization, Grain, Austenite, Inclusions, Samples
Keywords:
In-situ, Electrochemistry, DSS, Pitting, CPT, Ferrite, Austenite, Inclusions, Precursor Sites
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2012
Association for Materials Protection and Performance (AMPP)
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