Distinction in Corrosion Behaviors of Duplex Stainless Steel 2205 Induced by Different Waveform Alternating Voltages Interference

Abstract

Anisotropic corrosion behaviors of duplex stainless steel induced by different waveform alternating voltage (AV) interferences have never been elucidated. The results of FeCl 3 pitting immersion tests reveal that the critical pitting temperature (CPT) of 2205 samples is decreased with the interferences of three waveform AV signals. For the AV with equal root mean square (RMS) value on electrode samples, the triangular wave induces much stronger etching on DSS 2205 than the sinusoidal and square ones. However, the sinusoidal and triangular AV interferences trigger the most severe pitting corrosion in high-temperature solution (>50°C). The weight loss induced by pitting corrosion is greater than that by strong etching on samples. Regarding the etching behavior, the austenite in the duplex phase exhibits an inferior corrosion resistance and is preferentially dissolved.