Silicon ion implantation on austenitic and ferritic stainless steels against localized aqueous corrosion

Silicon ion implantation has been used as a surface modification technique in order to improve the corrosion resistance of two stainless steels with similar passive layers but different microstructures, such as AISI 304 (austenitic) and AISI 430 (ferritic). For each steel, different doses of silicon ion implantation (1×1014, 5×1014, 1×1015 ions/cm2) at an energy of 80 keV have been tested. Theoretical simulations using the TRIM 96 computer code have been performed in order to estimate the Si implantation profiles. The corrosion resistance of the Si-implanted stainless steels was analysed using electrochemical impedance spectroscopy (EIS) in a 0.5 M NaCl solution. The surface was characterised by auger electron spectroscopy (AES). The effect of optimum doses of Si-implanted stainless steels on the corrosion behaviour is discussed.