This work is the study of the influence of liquid nitriding treatment on the electrochemical and mechanical behavior of two metallic materials, the titanium based alloy β-CEZ and 9S20K carbon steel. The obtained micrographs clearly showed the structural changes happened to occur during this treatment and allowed to delimit the nitrided layer. The X-ray diffraction of the treated samples permits identification of different titanium and iron nitrides formed. The Vickers microhardness tests carried out on perpendicular sections of the nitrided samples (of β-CEZ, 9S20K) showed the increase of surface hardness. Electrochemical characterisation results showed the increase in the corrosion resistance of the nitrided 9S20K steel and the decrease of the nitrided β-CEZ alloy corrosion resistance in comparison with untreated specimens. Obtained results showed that the nitriding treatment allowed improving the mechanical and electrochemical behavior of 9S20K steel, but the nitriding treatment only improved the mechanical properties of the titanium alloy and its electrochemical behavior became worse.