2014 Volume 65 Issue 7 Pages 330-337
To develop a safe and environmentally friendly passivation treatment, the pitting resistance of Type 304 stainless steels, which were finished with different polishing methods and then passivated in H2O2 solutions under various conditions, were examined by measuring their pitting potentials in deaerated 3.5 %NaCl. Results show that pitting potentials were strongly dependent on the surface polishing conditions. A remarkable increase in pitting potential was attained on an electro-polished surface. The highest resistance to pitting was obtained on a surface treated in 3.5 %H2O2 at 25 °C for 2 h. The steels treated under this condition showed extremely high pitting potential of 1075 mV(vs. Ag/AgCl(sat. KCl)) in 3.5 %NaCl, but they showed no change in pitting potential after immersion in aerated 3.5 %NaCl for 100 d.
