ELECTROCHEMICAL BEHAVIOUR OF AISI ۳۰۴ STAINLESS STEEL IN SULFURIC SOLUTION: EFFECTS OF ACID CONCENTRATION

The effects of H۲SO۴ concentration on the electrochemical behaviour of passive films formed on AISI ۳۰۴ stainless steel were investigated using by potentiodynamic polarization, Mott–Schottky analysis and electrochemical impedance spectroscopy (EIS). Potentiodynamic polarization indicated that the corrosion potentials were found to shift towards negative direction with an increase in solution concentration. Also, the corrosion current densities increase with an increase in solution concentration. Mott–Schottky analysis revealed that the passive films behave as n-type and p-type semiconductors at potentials below and above the flat band potential, respectively. Also, Mott– Schottky analysis indicated that the donor and acceptor densities are in the range ۱۰۲۱ cm-۳ and increased with solution concentration. EIS data showed that the equivalent circuit Rs(Qdl[Rct(RrQr)]) by two time constants is applicable.

کلیدواژه ها:

Stainless steel ، Concentration ، Potentiodynamic polarization ، Equivalent circuit ، Mott–Schottky