Pitting and etching behaviors occurring in duplex stainless steel 2205 in the presence of alternating voltage interference

The corrosion of duplex stainless steel (DSS) 2205 induced by alternating voltage (AV) is a new degradation case and distinct behaviors of duplex phase under AV interference are still unknown. The standard FeCl3 pitting test was employed to investigate the pitting corrosion of DSS 2205 with AC interference. The results reveal the AV signal reduces the critical pitting temperature of DSS 2205. The etching behavior occurs under AV signal with high amplitudes in 30 degrees C solution. However, big pits propagate under AV interference with lower amplitudes in 40, 50 degrees C solutions. The etching and pitting are suppressed with increasing frequency in 30 and 40 degrees C solutions. The increase in frequency fails to drastically suppress the pitting corrosion in 50 degrees C solution. The solution with higher temperature (>50 degrees C) easily triggers pits on DSS 2205 samples regarding the lower amplitude AV signals and higher frequency. The cross sectional morphologies also reveal that the AV-induced pits exhibit a strong lateral-growth tendency based on the dish shape. (C) 2019 Elsevier Ltd. All rights reserved.