Effect of Inorganic Anions on the Pitting Behaviour of Austenitic Stainless Steel 304 in H₂SO₄ Solution Containing Chloride Ion

摘要

The effect of addition of inorganic anions, silicate, periodate and permanganate on the pitting behaviorof stainless steel 304 in 0.5M H2SO4 containing 0.1M NaCl was studied using electrochemicalimpedance spectroscopy (EIS) and potentiodynamic polarization techniques. In the absence andpresence of silicate ion, the peak characteristic for the reduction of sulphate ion was clear in thepotentiodynamic polarization curve. This peak was also present in presence of low concentrations ofperiodate or permanganate but disappeared at high concentrations of both anions. This indicates thatperiodate or permanganate ions possess a great pitting inhibition at high concentrations, this was alsoconfirmed by EIS technique.