Thiosulfate Pitting Corrosion of Stainless Steels in Paper Machine Environment

摘要

Thiosulfate pitting corrosion of austenitic stainless steels of types UNS S30403211u001e(AISI 304L) and UNS S31603 (AISI 316L), and duplex stainless steel of type UNS 211u001eS31803 (22Cr DSS) was studied in simulated paper machine environments containing 211u001echloride, sulfate and thiosulfate by cyclic polarization scans, scratch tests, 211u001eContact Electric Resistance (CER) technique and by corrosion coupon tests 211u001eperformed in a real paper machine. The formed pits and crevice corrosion were 211u001eexamined by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray 211u001eSepctroscopy (EDS). The surface films were also analyzed by Electron Spectroscopy 211u001efor Chemical Analysis (ESCA) and Secondary Ion Mass Spectrometry (SIMS).