Effects of N and Mo on the electrochemical behavior of laser-alloyed stainless steels in a 3.5 wt.% NaCl solution

The electrochemical behavior of the laser-alloyed Fe-Cr-Ni-Si-N and Fe-Cr-Ni-Mo-Si-N stainless steels was studied in a 3.5 wt.% NaCl solution. Cyclic potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) measurements were performed to evaluate the corrosion resistance of the alloyed layers in deaerated 3.5 wt.% NaCl solution at pH 4. The surfaces of the samples after EIS measurements were characterized with X-ray photoelectron spectroscopy. The experimental results showed that the passivation and polarization resistance of laser-alloyed nitrogen-containing stainless steels in chloride-containing solution could be improved by co-alloying molybdenum. The electrochemical behavior in connection with the chemical states of alloying elements on the surfaces of the alloys was discussed.