A coating-diffusion method based on cathodic arc physical deposition (CA-PVD) is introduced for the production of titanium carbide on steel substrates. The method allowed the production of TiC layer in a temperature range of 1000-1200 degrees C in a controlled manner. The Fe-Ti compounds forming at the initial diffusion states are the source of iron in TiC. The free energy of formations indicated that Fe-Ti alloying at the interface takes place after depletion of C. The initially formed TiC layer does not grow in layer mode and kinetically hinders the reaction between carbon depleted zones in the steel. As the process proceeds, iron in the Fe-Ti compounds at the substrate diffusion layer interface is released with the carburization of titanium and carried towards the surface either by deposited fresh titanium layers or macroparticles. Macro particles played an essential role in collecting and carrying iron to the surface of the TiC layer.