The influence of high nitrogen austenitic surface layer formation on the corrosion resistance of Fe-23Cr-2.4Mo ferritic stainless steel

In the work the corrosion resistance of ferritic- austenitic dual layer steel composed of ferritic core and nickel-free high nitrogen austenitic stainless steel (HNASS) sell, in 0.5M H2SO4solutionwas investigated and was compared with the initial ferritic and conventional 316L austenitic steels. Austenitic high nitrogen layer was produced by high temperature gas nitriding if initial ferritic steel at 1200℃ for 2 hour. Corrosion resistance was investigated by recording open circuitpotential, potentiodynamic polarization curves and electrochemical impedance spectra. Resultsshowed that HNASS steel has a high general corrosion resistance compared with the intial ferritic and conventional 316L Austenitice stainless steels which was related to the formation of the thicker protective passive film on the HNASS steel

Keywords:

ferritic- austenitic dual layer steel , nickel-free high nitrogen austenitic stainless steel , open circuit potential , potentiodynamic polarization , electrochemical impedance spectra , general corrosion resistance