Nitriding of titanium by NH3 RF plasma: a study of the corrosion resistance and the mechanical properties of the protective films formed at the solid surface

The exposure of a titanium sample to an NH3 low pressure plasma leads to the formation of a nitriding layer. The products formed at the titanium surface were identified by XRD spectroscopy. The modification of the corrosion resistance characteristics of titanium due to the NH3 plasma treatment were investigated by electrochemical tests. The recorded polarization curves of the treated titanium samples were used to determine the values of the corrosion potential Ecorr. This study confirms the increasing of the corrosion resistance as a function of the time exposure and the injected electric power in the silica reactor. The plasma treatment also induces drastic changes of the titanium target in hardness.