This studyproposes by meansof analytical characterization techniques, astructural evaluation of the surfacemodification of aferrous material bythree-dimensionalion implantationplasma technology.Carbon steel substrates immerse in a gaseous atMo sphere,were surface implantedwith nitrogen ionsvia high voltage pulse discharges activated at a low-pressure range (“high vacuum”).The effect of the surface treatment on the structure, composition and morphology of the substrates was verified by microscopy and spectroscopy techniques. From the micrographs obtained by scanning electronic microscopy and the analysis elemental by energy dispersive spectroscopy the morphology and nitrogen concentration of thetreated and non-treated samples wereanalyzedand compared. As for the elemental analysis by energy dispersive spectroscopy, nitrogen concentration in the implanted substrates were detected and determinedat a relatively low amount. In regard to the X-raydiffraction results, a decrease in the intensity of the (110), (200)and (211)planes of the treated substratecompared with the reference substrate,wasobserved. Theanalysis ofphases-formation onthe surface materialperformed by Raman spectroscopy, identified mainly ferric oxy-hydroxidestypical uniform corrosion products.

In this research, the concentration-depth profiles reached by titanium and nitrogen particles, on the surface of AISI/SAE 1020 carbon steel substrates, by using of ion implantation technique, are studied. The ions are surface deposited by means of high voltage pulsed discharges and electric arc discharge under high vacuum conditions. The concentration and position distribution of the metallic and non-metallic species are obtained by simulation of the interaction of ions with the matter, stopping and ranges of ions in the matter, by the computer program transport of ions in matter. The implantation dose is calculated from the discharge data and the previously established study parameters in this work. From the simulation results, the depth profiles demonstrated that titanium and nitrogen ions may reach up to 300 Å and 600 Å and concentrations of 1.478 x 1016 ions⁄cm2 and 2.127 x 1016 ions⁄cm2, respectively. The formation of titanium microdroplets upon the surface of the substrates is identified from the micrographs obtained by the scanning electron microscopy technique; furthermore, the presence of titanium and nitrogen implanted on the surface of the substrate is verified through the elemental composition analysis by the energy dispersive spectroscopy, validating the effect of ion implantation on ferrous alloys.

Martensitic-grade stainless steels are widely used in diverse industrial and surgical applications, despite their natural tendency to suffer local and uniform corrosion when continuously exposed to aggressive operation conditions. In order to enhance their surface properties, this paper characterized the performance, in saline solutions, of AISI 420 stainless steel, which was surface-modified by three-dimensional ion implantation using electrochemical techniques. The surface of the samples was implanted with ionized nitrogen particles with an energy of 10 keV, varying the implantation time between 30 and 90 minutes. After the surface treatment, the samples were exposed to a NaCl 3% (w/w) aqueous solution for 21 days. Tafel extrapolation, linear polarization resistance, and electrochemical impedance spectroscopy tests were performed, with the purpose of quantifying the effect of the ion implantation technique against electrochemical corrosion. To establish a comparison, the same tests were also performed on non-treated samples. The results indicated an increase in the corrosion potential, polarization resistance, and a decrease in the current density of implanted samples, thus demonstrating that, by delaying corrosive activity, traditional ion implantation offers better protection against electrochemical corrosion in AISI 420 stainless steel samples implanted with nitrogen.