In this study, the new Hardion+ micro-implanter technology was used to modify surface properties of biomedical pure titanium (CP-Ti) and Ti-6Al-4V ELI alloy by implantation of nitrogen ions. This process is based on the use of an electron cyclotron resonance ion source to produce a multienergetic ion beam from multicharged ions. After implantation, surface analysis methods revealed the formation of titanium nitride (TiN) on the substrate surfaces. An increase in superficial hardness and a significant reduction of friction coefficient were observed for both materials when compared to non-implanted samples. Better corrosion resistance and a significant decrease in ion release rates were observed for N-implanted biomaterials due to the formation of the protective TiN layer on their surfaces. In vitro tests performed on human fetal osteoblasts indicated that the cytocompatibility of N-implanted CP-Ti and Ti-6Al-4V alloy was enhanced in comparison to that of the corresponding non treated samples. Consequently, Hardion+ implantation technique can provide titanium alloys with better qualities in terms of corrosion resistance, cell proliferation, adhesion and viability.

In this study, a superelastic Ni-free Ti-based biomedical alloy was treated in surface by the implantation of nitrogen ions for the first time. The N-implanted surface was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and secondary ion mass spectroscopy, and the superficial mechanical properties were evaluated by nano-indentation and by ball-on-disk tribological tests. To investigate the biocompatibility, the corrosion resistance of the N-implanted Ti alloy was evaluated in simulated body fluids (SBF) complemented by in-vitro cytocompatibility tests on human fetal osteoblasts. After implantation, surface analysis methods revealed the formation of a titanium-based nitride on the substrate surface. Consequently, an increase in superficial hardness and a significant reduction of friction coefficient were observed compared to the non-implanted sample. Also, a better corrosion resistance and a significant decrease in ion release rates have been obtained. Cell culture experiments indicated that the cytocompatibility of the N-implanted Ti alloy was superior to that of the corresponding non-treated sample. Thus, this new functional N-implanted titanium-based superelastic alloy presents the optimized properties that are required for various medical devices: superelasticity, high superficial mechanical properties, high corrosion resistance and excellent cytocompatibility.

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Friction and wear properties modification of ti-6Al-4V alloy surfaces by implantation of multicharged carbon ions, Wear,

The effect of high energy ion bombardment on ultra-thin Pt films deposited on silicon substrates was investigated. The changes caused by the bombardment were studied using a combined characterization approach, consisting of X-Ray Photoelectron Spectroscopy (XPS) and electrochemical measurements. The chemical sensitivity of XPS helped determine locally the nature of the film after bombardment, which transitions to platinum silicide, as demonstrated by a dramatic evolution of the Pt4f and valence band spectra. Cyclic voltammetry provided the average electrochemical response of the entire sample surface (1 cm 2 ) in contact with an acidic solution. This technique is particularly sensitive to the evolution of the platinum undergoing bombardment. Initially showing a typical Pt electrochemical response, the film undergoes an irreversible transformation, leading to the absence of any metallic platinum on the surface after a sufficient bombardment dose, based on the absence of electrocatalytic activity. This study highlights the complementarity of XPS and electrochemical characterization. The platinum silicide fabrication technique described here may also be of interest for electronics applications, since platinum silicide contacts are used in a variety of thin film devices.