In the present study unalloyed spheroidal graphite iron was compared with a sample alloyed with copper and nickel (Cu- Ni). Samples of those materials were treated in salt bath (a composite of sodium borate, aluminum, iron-niobium and/or iron-vanadium) at 1000 °C for 2 hours. This resulted in layers of niobium carbide (NbC), vanadium carbide (VC) and ternary carbide of niobium and vanadium (NbVC2). Characterization of these layers was obtained by optical microscopy, X-ray diffraction and microhardness Vickers. The microhardness and the thickness results were statistically analyzed by the two factors variance analysis method. The efficiency of the layered surface in increasing corrosion resistance was demonstrated by submitting it to potentiodynamic polarization corrosion tests.