Electrochemical investigation of pickled and polished 304L stainless steel tubes

The influence of two pickling methods and mechanical polishing on polarization resistance, passive current density and break-down potential of 304L tubes was investigated by EIS and potentiodynamic measurements in 0.05 M H2SO4 + 0.05 M NaCl solution. The electrochemical cell was specially designed to separately measure outer and inner surfaces of tubes. The results demonstrated that the outer and inner surfaces of tubes could be separately evaluated by the electrochemical measurements using the cell configuration. Differences in the electrochemical behavior were observed between pickled and polished tubes, between the inner and outer surface of tubes, and between the two pickling methods.