Corrosion Behavior of TTS443 Ferrite Stainless Steel in NaCl or HCl Solution

The corrosion behavior especially pitting resistance of TTS443 stainless steel, in comparison with 304 stainless steel, was studied by means of polarization curves and electrochemical impedance spectroscopy(EIS), in NaCl and HCl solutions respectively. The results showed that, with the increase of mass fraction of Cl-, the pitting potential(Eb) of TTS443 stainless steel decrease first and then increase,and corrosion current(Icorr) increase first and then decrease, in12%NaCl solution, while the corrosion rate was the highest. In solutions with the same concentrati on of Cl-the corrosion rate of TTS443 stainless steel was slower than 304, but the pitting corrosion resistance is weaker. However in HCl solution, with the increase of concentration of HCl, the corrosion rate was increased, the value of Eb reduced. In solutions with the same acidity, the corrosion rate of TTS443 stainless steel was faster, and the pitting corrosion resistance was weaker rather than 304 stainless steel.